The DOI matches its Crossref record; 232 of the 232 references it cites were found in a registry or an index; 1 of the 246 sources its claims cite were checked for support.
Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions†
Open accessAbstract
The survey focuses on recent aspects of photochemical reactions to cellular DNA that are implicated through the predominant formation of mostly bipyrimidine photoproducts in deleterious effects of human exposure to sunlight. Recent developments in analytical methods have allowed accurate and quantitative measurements of the main DNA photoproducts in cells and human skin. Highly mutagenic CC and CT bipyrimidine photoproducts, including cyclobutane pyrimidine dimers and pyrimidine (6‐4) pyrimidone photoproducts (6‐4PPs) are generated in low yields with respect to TT and TC photoproducts. Another striking finding deals with the formation of Dewar valence isomers, the third class of bipyrimidine photoproducts that is accounted for by UVA‐mediated isomerization of initially UVB generated 6‐4PPs. Cyclobutadithymine (T<>T) has been unambiguously shown to be involved in the genotoxicity of UVA radiation. Thus, T<>T is formed in UVA‐irradiated cellular DNA according to a direct excitation mechanism with a higher efficiency than oxidatively generated DNA damage that arises mostly through the Type II photosensitization mechanism. C<>C and C<>T are repaired at rates intermediate between those of T<>T and 6‐4TT. Evidence has been also provided for the occurrence of photosensitized reactions mediated by exogenous agents that act either in an independent way or through photodynamic effects.
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In the paper
“It is now well documented that DNA is the main critical cellular macromolecule for determining the carcinogenic effects of solar radiation (7)(8)(9).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > INTRODUCTION
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In the paper
“Overall cumulated dose is a good predictor of induction of squamous cell carcinoma and lip cancers (1).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > INTRODUCTION
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In the paper
“In contrast, basal cell carcinoma and malignant melanoma incidence appears to be mostly related to intermittent exposure to solar light during childhood and adolescence (1), although the situation for melanoma appears to be more complex (2).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > INTRODUCTION
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In the paper
“Occupational and recreational exposure of humans to UVB and UVA radiations present in sunlight represents a major environmental risk factor for the development of skin cancers.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > INTRODUCTION
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In the paper
“Another early relevant finding dealt with the isolation of a second thymine dimeric photoproduct in UVC-irradiated thymidylyl-(3¢-5¢)-thymidine (TpT) (25) that has been identified as a pyrimidine (6-4) pyrimidone photoproduct (6-4PP) (26,27).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > INTRODUCTION
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In the paper
“with the observation of UVB-induced C fi T transition and CC fi TT mutations at bipyrimidine sites in p53 genes of skin tumors (8,15).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > INTRODUCTION
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“T< >T has been shown later to be the predominant DNA photoproduct induced in cellular DNA upon UVB and solar irradiation (22).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > INTRODUCTION
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- Not checked yetcites [22] source
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In the paper
“DNA damage induced by UVB radiation is dominated by bipyrimidine photoproducts (22).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVB-induced CPDs and 6-4PPs
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- Not checked yetcites [22] source
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In the paper
“The formation of oxidation products, more specifically 8-oxodGuo, is also induced in cellular DNA upon exposure to UVB radiation however in a low yield that is 2-3 orders of magnitude lower than that of either CPDs or 6-4PPs (32).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVB-induced CPDs and 6-4PPs
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- Not checked yetcites [32] source
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In the paper
“The formation of these photoproducts results from the presence of a pyrimidone moiety in 6-4PPs that may absorb photons with a maximal efficiency around 320 nm.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Main properties of the photoproducts.
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In the paper
“As a result, exposure of ds DNA and cells to either simulated sunlight (SSL), a combination of UVA and UVB, or sequential exposure to UVB and UVA leads to the photoisomerization of a large fraction of 6-4PPs into DEWs (54-56).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Main properties of the photoproducts.
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In the paper
“In contrast, the reaction is much more efficient when the C5-C6 double bond is saturated as is the case in CPDs and for the 5¢-end bases of 6-4PPs and DEWs (57).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Main properties of the photoproducts.
What the sources say
- Not checked yetcites [57] source
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“A first example is given by the photoinduced conversion of 6-4PPs into a third class of dimeric photoproducts (Fig. 1) known as the DEWs (50).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Main properties of the photoproducts.
What the sources say
- Not checked yetcites [50] source
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In the paper
“Although interstrand photoproducts can be obtained under very specific conditions within isolated DNA (46), the biologically relevant CPDs involve adjacent bases.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVB-induced CPDs and 6-4PPs
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- Not checked yetcites [46] source
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In the paper
“The 6-4PP rearrangement to Dewar valence isomers in ds DNA can be triggered by UVB radiation with however a low efficiency that requires exposure to biologically irrelevant high doses (53).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Main properties of the photoproducts.
What the sources say
- Not checked yetcites [53] source
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“Recently, it was shown that the efficiency of the reaction can be modulated in cells by processes such as stalling of RNA polymerase at CPD sites during transcription (58).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Main properties of the photoproducts.
What the sources say
- Not checked yetcites [58] source
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The four main possible CPDs that correspond to the TT, CT, TC and CC bipyrimidine sequences have been isolated in both naked and cellular DNA.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVB-induced CPDs and 6-4PPs
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In the paper
“Therefore, the CPD that is exclusively generated exhibits a cis-syn stereochemistry.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVB-induced CPDs and 6-4PPs
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“However, it may be mentioned that transfection of cells and mice with photolyases that specifically remove either CPDs or 6-4PPs indicated that the former types of lesions are responsible for the vast majority of mutagenic events induced by UV irradiation (47,48).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVB-induced CPDs and 6-4PPs
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In the paper
“HPLC-ESI-MS ⁄ MS measurement also revealed that the four CPDs were not repaired with the same rate, being enzymatically removed in the following increasing order of efficiency: T< >T < T<>C < C<>C C<>T (49).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVB-induced CPDs and 6-4PPs
What the sources say
- Not checked yetcites [49] source
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“The first class consists of the well-known CPDs that arise from a [2+2] cycloaddition reaction between the C5-C6 double bonds of two pyrimidines.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVB-induced CPDs and 6-4PPs
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In the paper
“A second major reaction that concerns the three types of bipyrimidine dimers is a hydrolytic process that converts 5,6dihydrocytosine moieties into 5,6-dihydrouracil residues.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Main properties of the photoproducts.
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In the paper
“This reaction takes place in a few picoseconds as shown by recent time-resolved measurement in single-stranded DNA (45).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVB-induced CPDs and 6-4PPs
What the sources say
- Not checked yetcites [45] source
plaindirect- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“6-4PPs are produced by a [2+2] cycloaddition between the C5-C6 double bond of the 5¢-end base and the C4 carbonyl group of a 3¢-end thymine, the so-called Paterno`-Bu¨chi reaction.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVB-induced CPDs and 6-4PPs
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In the paper
“A similar CPD distribution was observed upon exposure to SSL that consists at the most 5% UVB in UVA (54).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
What the sources say
- Not checked yetcites [54] source
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“The corresponding 6-4PPs were detected only in small amounts in isolated DNA exposed to rather large doses of UVB.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“For example, HPLC-ESI-MS ⁄ MS analysis showed that UVB irradiation of mammalian cells (53,54,56,60) and human skin (61) induces T<>T as the most frequent photoproduct.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
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plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“The values reported range between 3 and 5 (53,55,59).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
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In the paper
“In terms of absolute yields of lesions, calibrated immunoassays, electrophoretic analysis and chromatographic measurements lead to values ranging between 0.2 and 0.5 per 10 6 bases per J m )2 upon exposure of cultured cells to UVB (55,61,62).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“Interestingly, immunohistochemical analyses have shown that, for UV radiation sources with wavelengths higher than 300 nm, the frequency of CPDs and 6-4PPs remains constant in all the layers of the epidermis 63-65.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
What the sources say
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“The corresponding 6-4TT is produced in a 10-fold lower yield.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
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In the paper
“Interestingly, the sites of high photoreactivity were also found to be mutational hotspots.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
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In the paper
“In fact, UVA radiation has been shown since the 1970s, first in bacteria (29) and then in mammalian cells (32,55,(80)(81)(82)(83)(84) and human skin (61,65,(85)(86)(87), to be also able to induce CPDs.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-induced CPDs
What the sources say
- Not checked yetcites [29] source
- Not checked yetcites [32] source
- Not checked yetcites [55] source
- Not checked yetcites [80] source
- Not checked yetcites [81] source
- Not checked yetcites [82] source
- Not checked yetcites [83] source
- Not checked yetcites [84] source
- Not checked yetcites [61] source
- Not checked yetcites [65] source
boosteddirect- Asserted: passes — The authors put it forward as true.
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In the paper
“Structural parameters have also to be taken into account, such as the nucleosome positioning that modulates the photoreactivity and therefore the ratio formation between 6-4PPs and CPDs (69).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
What the sources say
- Not checked yetcites [69] source
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“It was shown for instance that the frequency of CPDs was not the same at all sites in a gene like p53, with ratios varying for more than 10 between the less and the most damaged ones (47).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
What the sources say
- Not checked yetcites [47] source
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“The yield of pyrimidine dimers in skin is also strongly modulated by the phototype-dark skin accumulating lower amounts of lesions than fair ones (66,67).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
boostedcorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“It was found that most mutations were C fi T transitions at bipyrimidine sites (11,90,91), in fact the mutational hallmark of UV-induced CPDs.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-induced CPDs
What the sources say
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“It is now well documented that UVA irradiation gives rise to CPDs in both cultured cells and human skin.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-induced CPDs
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In the paper
“As a striking information, the yield of CPDs was found to be larger than that of oxidatively generated lesions such as 8-oxoGua (32,46,61,88) that were long thought to be the hallmark of UVA genotoxicity, as further discussed below.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-induced CPDs
What the sources say
boosted- Asserted: passes — The authors put it forward as true.
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In the paper
“The ratio between the yields of CPDs and 8-oxoGua is around 5, slightly depending on the cell type.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-induced CPDs
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“Although tiny amounts of 6-4PPs have been detected by immunological assays (55), neither the formation of this class of damage nor of DEWs has been observed using more specific chromatographic techniques, even at high doses of UVA (46,61,88).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-induced CPDs
What the sources say
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“There is however an exception for melanocytes where a CPD ⁄ 8-oxoGua ratio 1.4 reflects the occurrence of a larger oxidative stress (89).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-induced CPDs
What the sources say
- Not checked yetcites [89] source
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“Interestingly, chromatographic measurements showed that, in calf thymus DNA triplet transfer photosensitization using ketone compounds leads to the predominant formation of T< >T (90%) together with lower amounts of T< >C and C< >T as observed in UVA-irradiated cells (54,93).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-induced CPDs
What the sources say
- Not checked yetcites [54] source
- Not checked yetcites [93]
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“Comparative experiments showed that the yields of UVA-induced CPDs were similar in isolated and cellular DNA (55,96,97).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-induced CPDs
What the sources say
plain- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This suggests that endogenous sensitizers play at best a minor role in the formation of these photoproducts.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-induced CPDs
hedged- Asserted: passes — The authors put it forward as true.
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In the paper
“The UVA-mediated oxidation reactions to cellular DNA have suggested to be initiated by the interaction of incident long UV wavelength radiation with endogenous chromophores (7,22,34).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > The diversity of DNA photo-oxidation mechanisms
What the sources say
- Not checked yetcites [7]
- Not checked yetcites [22] source
- Not checked yetcites [34]
hedgeddirect- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“A common photosensitized pathway involves the production of singlet oxygen ( 1 O 2 ) according to the so-called Type II photosensitization pathway that results from energy transfer from the triplet excited sensitizer to molecular oxygen.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > The diversity of DNA photo-oxidation mechanisms
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In the paper
“Although this working hypothesis has been under investigation for many years, the exact nature of the involved natural photosensitizers remains unclear (98).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > The diversity of DNA photo-oxidation mechanisms
What the sources say
- Not checked yetcites [98] source
plain- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“It was found in DNA that guanine is the main target of one-electron oxidation reactions mediated by Type I photosensitization as the purine base exhibits by far the lowest ionization potential among DNA components (Fig. 5).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > The diversity of DNA photo-oxidation mechanisms
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Altogether, it seems now most likely that UVA-induced CPDs arise from a direct photoreaction.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-induced CPDs
hedgedconditional- Asserted: passes — The authors put it forward as true.
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None of the sources cited for this claim have been checked yet.
In the paper
“The distribution of oxidatively generated damage involving Type I photosensitization has been shown to be modulated, leading to an enhanced guanine specificity by the occurrence of charge transfer within DNA (104,105).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > The diversity of DNA photo-oxidation mechanisms
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“It was found that, oxidized purine bases and most likely 8-oxoGua, are the main UVA-induced oxidation products in UVA-irradiated cells (32,54,115).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-mediated oxidatively generated DNA damage in cells
What the sources say
hedgeddirect- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Therefore, detection of 8-oxoGua that is strongly indicative of occurrence of oxidative degradation reactions in DNA is however poorly informative in terms of the mechanisms involved.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-mediated oxidatively generated DNA damage in cells
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In the paper
“5-Hydroxymethyluracil (HmUra) and 5-formyluracil (ForUra) have also been characterized as the main • OH-mediated methyl oxidation products of thymine (109).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > •)
What the sources say
- Not checked yetcites [109] source
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“It may be added that • OH efficiently reacts with the 2-deoxyribose moieties by hydrogen abstraction according to several pathways that lead in most cases to the formation of DNA strand breaks (109).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > •)
What the sources say
- Not checked yetcites [109] source
hedgeddirect- Asserted: passes — The authors put it forward as true.
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In the paper
“O 2 •) may be also released in large amounts by mitochondria in cells in response to UVA irradiation (106).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > •)
What the sources say
- Not checked yetcites [106]
hedgedconditional- Asserted: passes — The authors put it forward as true.
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In the paper
“It is also well documented that • OH is able to react with pyrimidine bases at the C5-C6 double bond, leading to the formation of 5,6-dihydroxy-5,6-dihydrothymine (ThyGl) and 5,6-dihydroxy-5,6-dihydrocytosine (109).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > •)
What the sources say
- Not checked yetcites [109] source
boosteddirect- Asserted: passes — The authors put it forward as true.
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None of the sources cited for this claim have been checked yet.
In the paper
“A much more common biomarker of oxidatively generated damage to DNA is 8-oxoGua that has been found to be generated in significant yields upon exposure of cultured cells (85,112,113) and skin (61) to UVA radiation.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-mediated oxidatively generated DNA damage in cells
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“It was recently confirmed that UVA radiation, in contrast to earlier suggestions, is not able to generate double strand breaks (114).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-mediated oxidatively generated DNA damage in cells
What the sources say
- Not checked yetcites [114] source
boosted- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The reaction of • OH with purine bases leads to the transient formation of the C8-hydroxylated radical that gives rise to 8-oxoGua and FapyGua together with related adenine degradation products including 8-oxo-7,8-dihydroadenine (8-oxoAde) and 4,6-diamino-5-formamidopyrimidine (FapyAde), however, in much lower yields.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > •)
plaindirect- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“It was shown using the comet assay and the alkaline elution analysis that UVA irradiation of cells gave rise to the formation of alkali-labile sites, mostly strand breaks.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-mediated oxidatively generated DNA damage in cells
plaindirect- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“As mentioned above, 8-oxoGua that is a ubiquitous biomarker of oxidative DNA degradation reactions may be produced by 1 O 2 , one-electron oxidation and • OH.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-mediated oxidatively generated DNA damage in cells
hedgedconditional- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The level of oxidized pyrimidines is less than half of that of strand breaks.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-mediated oxidatively generated DNA damage in cells
plain- Asserted: passes — The authors put it forward as true.
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None of the sources cited for this claim have been checked yet.
In the paper
“A few photosensitizers including anthraquinone (137), benzophenone (138), 1,4-dimethyl-2-naphthoquinone (139) and riboflavin (140) are able to abstract one electron from adenine and pyrimidine bases in addition to guanine.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > SENSITIZED REACTIONS TO UVA RADIATION BY EXOGENOUS COMPOUNDS
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“However, the final DNA degradation products are predominantly generated at guanine”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > SENSITIZED REACTIONS TO UVA RADIATION BY EXOGENOUS COMPOUNDS
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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In the paper
“The predominant CPD photoproduct of the latter photosensitized reactions was found to be cis-syn T<>T, in agreement with the fact that thymine exhibits the lowest triplet energy (E T ) among nucleobases (148).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Triplet energy transfer
What the sources say
- Not checked yetcites [148] source
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“It was thus concluded that UVA formation of oxidatively generated damage to cellular DNA was mostly rationalized in terms of predominant implication of 1 O 2 with a minor contribution of • OH (25% in the case of 8-oxoGua).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-mediated oxidatively generated DNA damage in cells
What the sources say
- Not checked yetcites [115] source
boosteddirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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None of the sources cited for this claim have been checked yet.
In the paper
“In that respect guanine (135) is the major target of one-electron oxidation reactions of most Type I photosensitizers (136).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > SENSITIZED REACTIONS TO UVA RADIATION BY EXOGENOUS COMPOUNDS
What the sources say
- Not checked yetcites [135] source
- Not checked yetcites [136]
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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None of the sources cited for this claim have been checked yet.
In the paper
“This was recently illustrated for melanocytes that are more susceptible than other cell types to UVA-induced oxidatively generated damage to DNA both as isolated cells (89,116) and in pigmented mice (117).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-mediated oxidatively generated DNA damage in cells
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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None of the sources cited for this claim have been checked yet.
In the paper
“There is an abundant literature on the TTET-mediated formation of CPDs in ds DNA by several photosensitizers, including acetone (142), acetophenone (54,142), benzophenone (54,143), carprofen (144), fenofibric acid (143), fluoroquinolones (92,93,145), ketoprofen (143) and three pyridopsoralen derivatives (146,147).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Triplet energy transfer
What the sources say
boosteddirect- Asserted: passes — The authors put it forward as true.
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In the paper
“This does not only apply to isolated DNA as similar results were obtained in human cells exposed to highintensity nanosecond UVC pulses (128).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > IONIZATION OF NUCLEOBASES BY HIGH-INTENSITY UVC LASER PULSES
What the sources say
- Not checked yetcites [128] source
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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In the paper
“The predominant CPD photoproduct of the latter photosensitized reactions was found to be cis-syn T<>T, in agreement with the fact that thymine exhibits the lowest triplet energy (E T ) among nucleobases (148).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Triplet energy transfer
What the sources say
- Not checked yetcites [148] source
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“Similar observations were made following exposure of isolated genomic DNA exposed to high-intensity UVC pulsed radiation that operate on nucleobases through biphotonic ionization (127).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > IONIZATION OF NUCLEOBASES BY HIGH-INTENSITY UVC LASER PULSES
What the sources say
- Not checked yetcites [127] source
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“It was recently found using several fluoroquinolones exhibiting E T values within the energy range 253-273 kJ mol )1 that triplet energy of thymine in ds DNA was 267 kJ mol )1 (113).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Triplet energy transfer
What the sources say
- Not checked yetcites [113] source
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“The decrease by about 43 kJ mol )1 of the thymine E T value with respect to that of the isolated base was suggested to result from the occurrence of p-stacking and base pairing in DNA (92).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Triplet energy transfer
What the sources say
- Not checked yetcites [92] source
hedgedconditional- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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In the paper
“The efficiency of formation of T< >T that was assessed using the accurate HPLC-ESI-MS ⁄ MS method was found to decrease in the following order: enoxacin > norfloxacin > lomefloxacin (93).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Triplet energy transfer
What the sources say
- Not checked yetcites [93]
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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None of the sources cited for this claim have been checked yet.
In the paper
“Several examples of UVA-sensitized formation of CPDs by fluoroquinolones in the DNA of isolated cells (93,149,150) and mouse skin (151) are available.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Triplet energy transfer
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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In the paper
“Thus, UVA-excited lomefloxacin has been found to generate in human keratinocytes CPDs that were revealed as T4 endonuclease V-sensitive sites (149).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Triplet energy transfer
What the sources say
- Not checked yetcites [149] source
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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In the paper
“It was found that in most cases TTET was the predominant mechanism of photosensitized damage to DNA over the formation of 8-oxodGuo and DNA strand breaks.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Triplet energy transfer
What the sources say
- Not checked yetcites [93]
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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In the paper
“CPDs were also detected by immunoassay in the DNA of fibroblasts, keratinocytes and Caucasian melanocytes upon lomefloxacin photosensitization (150).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Triplet energy transfer
What the sources say
- Not checked yetcites [150] source
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“Carprofen, a nonsteroidal antiinflammatory drug, is also able to UVA sensitize the formation of CPDs in the DNA of human keratinocyte (HaCaT) cell lines as inferred from immunofluorescence detection and application of a modified version of the alkaline comet assay involving the use of T4 endonuclease V (152).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Triplet energy transfer
What the sources say
- Not checked yetcites [152] source
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“It may be emphasized that the photosensitized formation of CPDs by fluoroquinolones and carprofen in either cells or skin implies that the photosensitizers are located in the close vicinity of nuclear DNA in order to allow efficient TETT.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Triplet energy transfer
hedgeddirect- Asserted: passes — The authors put it forward as true.
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In the paper
“The method is sensitive enough to detect each of the two diastereomers that are formed with a yield of about 1 lesion per 10 4 base pairs in cellular DNA (166).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
- Not checked yetcites [166] source
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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In the paper
“Almost simultaneously, a HPLC fluorescence method has been reported for the measurement of the two cis-syn diastereomers of the furanside monoadducts of 3-carbethoxypsoralen (3-CPs) to thymidine in the DNA of S. cerevisiae and Chinese hamster V79 cells treated with monofunctional 3-CPs plus UVA radiation (166).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
- Not checked yetcites [166] source
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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None of the sources cited for this claim have been checked yet.
In the paper
“Essentially, the formation of two types of monoadducts as pairs of diastereomers through the implication of either the 4¢,5¢-double bond of the furan moiety or the 3,4-ethylenic bond of the pyrone ring has been reported.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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None of the sources cited for this claim have been checked yet.
In the paper
“While pyrone-side monoadducts to thymine are not photoreactive, UVA excitation of furan-side monoadducts may lead to the formation of harmful DNA interstrand cross-links (ICLs) through cycloaddition to opposite thymine at 5¢-TpA-3¢ sequences (Fig. 7) that are the preferential sites of photoreactions of most psoralen derivatives (35,(161)(162)(163).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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None of the sources cited for this claim have been checked yet.
In the paper
“While pyrone-side monoadducts to thymine are not photoreactive, UVA excitation of furan-side monoadducts may lead to the formation of harmful DNA interstrand cross-links (ICLs) through cycloaddition to opposite thymine at 5¢-TpA-3¢ sequences (Fig. 7) that are the preferential sites of photoreactions of most psoralen derivatives (35,(161)(162)(163).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This appears to be the most sensitive method available so far for monitoring the formation of psoralen-DNA biadducts and assessing their subsequent repair.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
None of the sources cited for this claim have been checked yet.
In the paper
“While pyrone-side monoadducts to thymine are not photoreactive, UVA excitation of furan-side monoadducts may lead to the formation of harmful DNA interstrand cross-links (ICLs) through cycloaddition to opposite thymine at 5¢-TpA-3¢ sequences (Fig. 7) that are the preferential sites of photoreactions of most psoralen derivatives (35,(161)(162)(163).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“Recently, a modified version of the alkaline comet assay that includes a postlysis c-irradiation step with a dose of 9 Gy has been designed for measuring DNA ICLs induced in HaCat cells upon treatment with 8-MOP plus UVA radiation (164).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
- Not checked yetcites [164] source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“The first individual measurement of biadducts and furan-and pyroneside mono adducts formed by photoreaction of 8-MOP with thymine in the DNA of Saccharomyces cerevisiae yeast cells has been achieved using a lipophilic Sephadex LH-20 column (165).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
- Not checked yetcites [165]
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
None of the sources cited for this claim have been checked yet.
In the paper
“The same remark applies to the detection of 8-oxoGua and Fpg-sensitive sites in cellular DNA upon UVA sensitization by methylene blue (182) and riboflavin (183), respectively.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“Therefore, ICLs induced by UVA activation of 8-MOP in the DNA of human skin melanoma cells were detected as tetranucleotides with a threshold sensitivity close to 1 ICL per 10 6 normal nucleosides.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
- Not checked yetcites [169] source
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“This has been recently overcome by the use of the versatile, specific and accurate electrospray ionization tandem mass spectrometry (ESI-MS ⁄ MS) technique in association with HPLC following nuclease P1 digestion of DNA (169).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
- Not checked yetcites [169] source
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“Further support for the predominant formation of 8-oxoGua among the DNA damage induced by UVA-excited rufloxacin UVA was provided by the enhanced frequency of GC>TA transversions in yeast after fluoroquinolone photosensitization (181).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
- Not checked yetcites [181] source
boosteddirect- Asserted: passes — The authors put it forward as true.
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In the paper
“It may be added that the two cis-syn diastereomers of 5-MOP to the furan-side to thymidine has been also measured in the DNA of S. cerevisiae using the same approach (168).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
- Not checked yetcites [168] source
hedged- Asserted: passes — The authors put it forward as true.
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None of the sources cited for this claim have been checked yet.
In the paper
“It was found that furan-and pyrone-side monoadducts of both 8-MOP and S59, a recently developed psoralen derivative for pathogen inactivation in blood products (171,172), are formed upon UVA irradiation in a much lower yield (close to 1%) than ICLs.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
plaindirect- Asserted: passes — The authors put it forward as true.
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None of the sources cited for this claim have been checked yet.
In the paper
“Formation of 8-oxoGua was observed in the DNA of cells photosensitized by norfloxacin (93) and rufloxacin (179,180).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“However, one of the main limitations of the fluorescence detection is that only furan-side monoadducts to pyrimidine bases can be measured.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“A much higher photoreactivity of S59, up to 2 orders of magnitude, with respect to 8-MOP was inferred from the measured levels of monoadducts and ICLs.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
- Not checked yetcites [170] source
hedgeddirect- Asserted: passes — The authors put it forward as true.
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In the paper
“A complementary analytical tool for monitoring the distribution of psoralen mono-and bi-adducts to pyrimidine bases in duplex oligodeoxynucleotides that involves the association of liquid chromatography with either UV ⁄ ESI-MS or IR multiphoton dissociation mass spectrometry has recently become available (173).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
- Not checked yetcites [173] source
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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None of the sources cited for this claim have been checked yet.
In the paper
“Fluorescent light-excited zinc meta N-methylpyridylporphyrin has been shown to induce oxidatively generated damage to DNA of human colon carcinoma LS174T cells, tentatively assigned as 8-oxoGua (184) on the basis of somewhat questionable immunodetection (185).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
hedgeddirect- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“It was not possible, however, in the above photochemical studies to assess the relative contribution of Type I and Type II mechanisms of DNA oxidation, likely to mostly involve 1 O 2 , as no specific one-electron oxidation decomposition guanine products such as FapyGua or Oz were measured.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
hedged- Asserted: passes — The authors put it forward as true.
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In the paper
“Support for the implication of • OH in the UVA activation of nanocrystalline TiO 2 was provided by atomic force microscopy (AFM) measurements showing a marked decrease in the stiffness of phototreated human skin fibroblasts (201).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
- Not checked yetcites [201] source
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“This that was partly prevented by the presence of metal chelators such as dipyridyl and neocuprine is suggestive of the predominant role of • OH in TiO 2 -sensitized formation of DNA damage to UVB.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
- Not checked yetcites [203] source
hedgedconditional- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“However, the lack of increase in the level of strand breaks and Endo III-sensitive sites would argue in favor of a significant contribution of 1 O 2 in the TiO 2 -photosensitized generation of oxidatively generated damage rather than of • OH.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
hedgedconditional- Asserted: passes — The authors put it forward as true.
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In the paper
“One may also quote a recent study in which preincubation of S. cerevisiae cells with normal size TiO 2 (>100 nm) led to an increase in mutation frequencies in both wild-type and 8oxoguanine DNA N-glycosylase strains upon UVB irradiation (203).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
- Not checked yetcites [203] source
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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In the paper
“Sunlight illumination of MRC-5 fibroblasts preincubated with TiO 2 was found to generate DNA strand breaks and ⁄ or alkali-labile sites as inferred from alkaline single-cell gel electrophoresis (199).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
- Not checked yetcites [199] source
hedgeddirect- Asserted: passes — The authors put it forward as true.
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In the paper
“Using alkaline comet analysis the anatase form of TiO 2 was shown to exhibit a higher photocatalytic ability than rutile to induce DNA damage in human bronchial epithelial cells (200).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
- Not checked yetcites [200] source
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“In agreement with quantum chemical calculations, it was found that the singlet excited state of the base was converted efficiently by very fast intersystem crossing into the triplet manifold.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [210] source
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“However, the formation yields of stable single oxidation products, including G S02 , G S03 and 8-oxoGua (206) in 6-TG containing isolated and cellular DNA are not available so far.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [206] source
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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None of the sources cited for this claim have been checked yet.
In the paper
“The formation of two other main classes of 6-TG-photosensitized photoproducts, including DPCs and DNA ICLs, was also observed in model compounds and CCRF-CEM leukemia cells (214,215).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
plaindirect- Asserted: passes — The authors put it forward as true.
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None of the sources cited for this claim have been checked yet.
In the paper
“An indication for the induction of the deleterious effects triggered by UVA activation of thiopurines was provided indirectly by the observed inhibition of transcription (207) and abrogation of cell-cycle checkpoints (208) in cultured human cells treated with thiopurine and UVA radiation through the generation of DNA damage.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
hedgeddirect- Asserted: passes — The authors put it forward as true.
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None of the sources cited for this claim have been checked yet.
In the paper
“However, a significant increase in the incidence of skin squamous carcinoma has been shown to be associated with long-term use of thiopurines in relation to solar radiation exposure, particularly in transplant patient recipients (204,206).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [204]
- Not checked yetcites [206] source
boostedcorrelational- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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None of the sources cited for this claim have been checked yet.
In the paper
“The main DNA oxidation products arise from 1 O 2 oxidation of the thiol function of 6-TG; they were characterized as stable guanine 6-sulphinate (G S02 ) and guanine 6-sulfonate (G S03 ) through initial transient guanine 6-sulphenate (G SO ) (212,213).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“The high triplet quantum yield value (F T = 0.8 ± 0.2) is likely to favor energy transfer to O 2 and therefore the generation of 1 O 2 (210).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [210] source
hedgedconditional- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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In the paper
“The quantum yields of 1 O 2 generation by UVA-excited 6-TG and related ribonucleosides that were almost simultaneously determined by time-resolution luminescence measurements at 1270 nm were found to vary within the 0.40-0.58range (211).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [211] source
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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In the paper
“Evidence was recently provided for the incorporation of 6-TG in mitochondrial DNA of HCT116 human cells (224).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [224] source
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Similarly, the 6-TG photosensitized formation of ICLs in cellular DNA could be also accounted for the covalent bond formation between opposite cytosine to Gua •+ as observed upon exposure DNA duplexes to high-intensity UVC nano-second pulses.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
hedgedconditional- Asserted: passes — The authors put it forward as true.
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None of the sources cited for this claim have been checked yet.
In the paper
“This leads to a high phototoxicity of the cells upon UVA-irradiation.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
plaindirect- Asserted: passes — The authors put it forward as true.
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None of the sources cited for this claim have been checked yet.
In the paper
“Other independent proofs that support the covalent attachment of nucleophilic amino acids to Gua •+ upon one-electron oxidation of oligonucleotides mediated by a Type I photosensitizer, the flash quench technique or biphotonic ionization, are available (219-222).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“A detailed model study of the formation of DPC has shown that the central lysine of KKK peptide was able to undergo highly efficient covalent attachment through its free e-amino group to one-electron oxidation guanine intermediate of the TGT trinucleotide (111) (Fig. 5).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [111] source
boosteddirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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None of the sources cited for this claim have been checked yet.
In the paper
“An alternative mechanism for the 6-TG-photosensitized formation of DPCs has been recently proposed (216) on the basis of the welldocumented reactivity of Gua •+ , the predominant oneelectron DNA oxidation transient radical formed, with relevant biological nucleophiles (111,134,136,217).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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None of the sources cited for this claim have been checked yet.
In the paper
“This was rationalized in terms of oxygenindependent formation of DNA photoproducts including an expected S5 thietane derivative, a 6-4PP analogue (227), through photocycloaddition with vicinal thymine and putative ICLs (228) that however remain to be characterized.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
hedgeddirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“Attempts to search for an increase in the level of 8-oxoGua in cellular S4Thy DNA were unsuccessful despite the fact that S4Thy is an efficient generator of 1O2 upon UVA irradiation (229).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [229] source
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Major progress in the measurement of DNA photoproducts in isolated cells and human skin exposed to either UVB, UVA and simulated solar radiation has been accomplished during the last decade.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > CONCLUSIONS
plain- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This is complemented by a better understanding of the photochemical pathways involved in the formation of DNA photoproducts in irradiated cells, mostly as the result of the availability of comprehensive mechanisms from detailed model studies.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > CONCLUSIONS
plaindirect- Asserted: passes — The authors put it forward as true.
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- Probably not a substantial claim. 7
- It may state two separate claims as one. 43
- The quote only partly states this claim. 1
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“Nanoparticles (ca 100 nm or smaller) of titanium dioxide (TiO 2 ), a white pigment, are widely used for various industrial purposes, including the design of sun blockers and other cosmetic products (187,188).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
- Partly supportedcites [187] sourceExperimental — accuracy not yet measured
The Titanium Dioxide section says TiO2 nanoparticles are used in cosmetic sunscreens and calls that use one of the most widely used early nanotechnology applications. It does not establish widespread use in other cosmetic products; its reference to TiO2 as a white pigment in cosmetics concerns the larger, micronized form, not nanoparticles. No page number is available in our copy. (LLM, conf=0.87)
- Not checked yetcites [188] source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
- Partly supported
None of the sources cited for this claim have been checked yet.
In the paper
“Other earlier striking findings concerning UVAinduced DNA photoproducts dealt with the identification of cyclobutane pyrimidine dimers (CPDs) (29,30) and oxidatively generated damage (30)(31)(32), including 8-oxo-7,8-dihydro-2¢deoxyguanosine (8-oxodGuo) (31) in cellular DNA.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > INTRODUCTION
What the sources say
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Another indirect evidence for the implication of photoinduced damage to DNA in carcinogenicity is provided by the high incidence of skin tumors in most of the complementation groups A-G of xeroderma pigmentosum patients (17,18) who suffer from deficiencies in nucleotide excision repair (19).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > INTRODUCTION
What the sources say
plaincorrelational- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Other photoproducts such as cytosine hydrates (41,42) or adenine-containing dimers (43,44) have been isolated in model systems but their yields are 2 orders of magnitude lower than that of bipyrimidine photoproducts in double-stranded (ds) DNA.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVB-induced CPDs and 6-4PPs
What the sources say
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The half reaction time is in the range of a few hours for isolated photoproducts and slightly less in ds DNA.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Main properties of the photoproducts.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“This reaction in DNA is mediated via singlet excited state as shown by the complete absence of formation of 6-4PPs upon photosensitized triplet state energy transfer.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVB-induced CPDs and 6-4PPs
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“and by the fact that 6-4PPs, although highly mutagenic, are efficiently removed by repair systems.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVB-induced CPDs and 6-4PPs
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Surprisingly, it was also reported that the 6-4TT lacking the internal phosphodiester bond is not able to undergo photorearrangement into the related Dewar valence isomer upon white light irradiation, suggesting that the DNA backbone could favor the photoisomerization of 6-4PPs.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Main properties of the photoproducts.
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“In contrast, CT and CC sites are much less susceptible to UVB-mediated reactions that lead mostly to the formation of CPDs.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“The yield of bipyrimidine photoproducts is much lower in skin than in cells, although the distribution of photoproducts is similar (61).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
What the sources say
- Not checked yetcites [61] source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In contrast, the frequency of 6-4PPs decreases and DEWs can be detected in significant amounts while they are not present when cells are only exposed to UVB (Fig. 2).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The TC sequences also show fair reactivity with both T< >C and 6-4TC being produced in similar yields.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Sequencing techniques showed that methylated CpG sites were more prone to photoproduct formation (72) and were mutational hotspots, likely as the result of deamination (73).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
What the sources say
- Not checked yetcites [72]
- Not checked yetcites [73] source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Evidence has also been provided for the enhanced efficiency of photoreactions in telomeres (70) with the possible formation of interstrand lesions in the quadruplex region (71).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Distribution of photoproducts in DNA.
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“The latter intermediate quantitatively rearranges within ds DNA into 8-hydroxyperoxyguanine (39,99) that is further reduced into 8-oxoGua (Fig. 5), the exclusive 1 O 2 oxidation product (39,100,101).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > The diversity of DNA photo-oxidation mechanisms
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“However, it is now established that 1 O 2 has no ability to cleave the DNA backbone and that earlier observations concerning formation of DNA nicks would be explained by the occurrence of secondary oxidation of 8-oxoGua that is about 100-fold more reactive than guanine toward 1 O 2 .”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > The diversity of DNA photo-oxidation mechanisms
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“It may be added, although being a much lower process than in the UVC and UVB ranges, that absorption of UVA photons by DNA is a well-documented fact (94) that was recently shown to be driven by the stacking of bases in the double helix (95,96).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-induced CPDs
What the sources say
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Indeed, neither UVB nor UVA photons provide enough energy to directly enable one-electron oxidation of DNA bases, although the double-stranded structure lowers the ionization potentials of the nucleobases.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-INDUCED OXIDATION REACTIONS (ENDOGENOUS PHOTOSENSITIZERS)
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
In the paper
“The singlet excited states arising from initial UVA photon absorption that are characterized by a marked charge transfer state appear to be quite different from those induced by UVB irradiation (95).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-induced CPDs
What the sources say
- Not checked yetcites [95] source
hedgedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“While bipyrimidine photoproducts are produced by direct excitation of the DNA bases, the formation of oxidatively generated lesions including 8-oxoGua obeys indirect photosensitized mechanisms (Fig. 4).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-INDUCED OXIDATION REACTIONS (ENDOGENOUS PHOTOSENSITIZERS)
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The unique target among DNA components is guanine that is converted into a 4,8-endoperoxide through 1 O 2mediated-Diels Alder [4+2] photocycloaddition reaction.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > The diversity of DNA photo-oxidation mechanisms
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“A second possible DNA photosensitization pathway involves one-electron oxidation by excited chromophores, also known as the Type I photosensitization mechanism.The efficiency of this reaction is driven by the oxidation potential of the photosensitizers that preferentially act on guanine.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > The diversity of DNA photo-oxidation mechanisms
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
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It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“In the case of UVA, • OH results from the fate of far less reactive O 2”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Hydroxyl radical-mediated DNA damage.
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
The quote only partly states this claim.
In the paper
“Interestingly, it was shown that UVA leads to the release of iron from ferritin, therefore potentiating emergence of Fenton reactions (107).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > •)
What the sources say
- Not checked yetcites [107] source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The second most frequent UVA-induced DNA oxidatively generated lesions are strand breaks that are formed in an approximately three-time lower yield than oxidized purines.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-mediated oxidatively generated DNA damage in cells
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Subsequently, O 2 •) can be converted by spontaneous or more likely by superoxide dismutase-driven dismutation into hydrogen peroxide (H 2 O 2 ).The latter species is the direct precursor of • OH upon reaction with reduced transition metal ions such as Fe 2+ or Cu + in a chemical process known as the Fenton reaction.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > •)
hedgeddirect- Asserted: passes — The authors put it forward as true.
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- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Upon loss of an electron, guanine is converted into a radical cation (Gua •+ ) that may undergo hydration with subsequent conversion to reducing the 8-hydroxy-7,8-dihydroguanyl radical.The latter transient radical is subsequently converted to 8-oxoGua and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua) by competitive one-electron oxidation and one-electron reduction, respectively.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > The diversity of DNA photo-oxidation mechanisms
What the sources say
- Not checked yetcites [103] source
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“As already mentioned, DNA only absorbs slightly in the lower part of the UVA range of solar radiation up to 340 nm, leading mostly to the formation of cis-syn T<>T through delocalization of excited state transients on several nucleobases (95,96).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > SENSITIZED REACTIONS TO UVA RADIATION BY EXOGENOUS COMPOUNDS
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Therefore, an increase in laser pulse intensity is accompanied with a decrease in the quantum yield of CPDs and 6-4PPs.In contrast, the level of 8-oxoGua, the main DNA oxidation product, and of other oxidized bases including 8-oxoAde, ThyGl, 5-HmUra and 5-FoUra increases (128).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > IONIZATION OF NUCLEOBASES BY HIGH-INTENSITY UVC LASER PULSES
What the sources say
- Not checked yetcites [128] source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Exposure of cells to low linear energy transfer ionizing radiation like X-or c-rays that act mostly through the production of • OH gives rise to strand breaks and oxidized bases in a 1.3:1 ratio while the formation yields of purine and pyrimidine oxidation products are similar.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > UVA-mediated oxidatively generated DNA damage in cells
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Furocoumarins including bifunctional 8-methoxypsoralen (8-MOP) and 5-methoxypsoralen (5-MOP) are still used in the so-called ''psoralen plus UVA (PUVA)'' therapy of rather frequent hyperproliferative skin diseases, including psoriasis and vitiligo (153-155).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
None of the sources cited for this claim have been checked yet.
In the paper
“Major mechanistic insights into the mechanisms of [2+2] photocycloaddition of furocoumarin derivatives to the 5,6-double bond of thymidine, the major target of these oxygen-independent photoreactions, have been gained from extensive model studies (35,(161)(162)(163).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Other applications of psoralen derivatives deal with the photopheresis of cutaneous T-cell lymphoma (156-158) and the photoinactivation of pathogens in plasma and platelet components (159,160).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
In the paper
“The repair rate of ICLs that is rather slow, requiring at least 24 h to be completed, was found to decrease with an increase in the concentration of 8-MOP (164).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
- Not checked yetcites [164] source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“The fast disappearance in the postincubation repair period of the two diastereomers with a half-life of about 90 min would suggest implication of the base excision repair pathway for their enzymatic removal.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Photocyloaddition reactions of psoralen derivatives
What the sources say
- Not checked yetcites [167] source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Among fluoroquinolones (for recent reviews, see Lhiaubet ), lomefloxacin and, to a lesser extent, enoxacin act as predominant Type I photosensitizers whereas ofloxacin and norfloxacin react with DNA mainly through 1 O 2 oxidation (93).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
- Not checked yetcites [93]
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“It was subsequently confirmed that ofloxacin oxidized predominantly DNA mostly through the Type II mechanism (177) as also shown for norfloxacin (178).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“UVA-excited TiO 2 has been shown to generate 1 O 2 (189), O 2) and also highly reactive • OH either through reduction of surface hydroxyl group by valence bond holes (190) or by Fenton type reactions (191).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“• OH has been also proposed to explain the increased level of oxidatively generated damage to DNA measured as Fpgsensitive sites in the DNA of UVA-irradiated goldfish skin GFSk-S1 cells pretreated with TiO 2 nanoparticles (202).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
- Not checked yetcites [202] source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
None of the sources cited for this claim have been checked yet.
In the paper
“Thiopurines including azathioprine, 6-mercaptopurine and 6thioguanine (6-TG) are widely used in cancer therapy, for the treatment of inflammatory disorders and as immunosuppressants (204,205).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [204]
- Not checked yetcites [205] source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Cationic 5,10,15,20-tetrakis (N-methyl-4-pyridyl)-21H,23H-porphyrin that is mostly localized in the nuclei of human leukemia HL-60 cells as inferred from confocal fluorescence microscopy is able to UVA sensitize the formation of 8-oxoGua through predominant Type II photosensitization mechanisms (186).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
- Not checked yetcites [186] source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“In contrast, protoporphyrin IX derived from 5-aminolevulinic acid and whose preferential localization was observed in the cytoplasm was found to generate only small amounts of 8-oxoGua upon UVA illumination (186).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
- Not checked yetcites [186] source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Photoexcited TiO 2 exhibits strong bactericidal activity (191)(192)(193)(194) and genotoxicity (195)(196)(197)(198) on various cells as mostly the result of oxidative stress.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidation reactions mediated by photosensitizers
What the sources say
boosteddirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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It may state two separate claims as one.
In the paper
“This is explained by the metabolization and incorporation of thiopurines into DNA as 6-thio-2¢-deoxyguanosine, an efficient endogenous Type I and Type II photosensitizer absorbing in the UVA range with a maximum at 342 nm (209).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [209] source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Some of the proposed structures of DPCs formed between oligonucleotides and short peptides involve covalent binding of highly reactive 6-TG with cysteine residues through the generation of a disulfide (214).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [214] source
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Free peptide amino groups were also suggested to participate in the 6-TG-mediated formation of DPCs.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [214] source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
None of the sources cited for this claim have been checked yet.
In the paper
“4-Thiothymine (S4Thy), a thymine analog absorbing in the UVA range with a maximum centered around 340 nm is able to efficiently incorporate into the DNA of dividing cells (225,226).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“However, the DPCs that were generated in cellular DNA were resistant to reduction treatment in contrast to those formed in model studies (214), ruling out the possible structures that were discussed above.”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [214] source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“In addition to water that was found initially to efficiently react with Gua •+ (218), several amino acids bearing a nucleophilic group, including lysine, arginine and serine were shown to covalent bind to the C8 of guanine (111,216).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“This was found to lead to the generation of ROS upon UVA irradiation with subsequent formation of DNA oxidation products that is accompanied by a loss of mitochondrial function (224).”
§ Photoinduced Damage to Cellular DNA: Direct and Photosensitized Reactions † > Oxidatively generated and complex DNA lesions induced by UVA activation of thiopurines
What the sources say
- Not checked yetcites [224] source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper relies on this without support.
Mechanisms of DNA photoproduct formation derived from model studies apply to cellular DNA.
“Major mechanistic insights into the mechanisms of [2+2] photocycloaddition of furocoumarin derivatives to the 5,6-double bond of thymidine, the major target of these oxygen-independent photoreactions, have been gained from extensive model studies (35,(161)(162)(163).”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In the citing paper
“6-4PPs are formed by one covalent bond between the 5'-end C6 and the 3'-end C4 carbon atoms of adjacent pyrimidines via charge-transfer states, and oxetane and azetidine rearrangements (unstable intermediates) occur when the 3'-end is T or C, respectively [31,32].”
From Sunlight damage to cellular DNA: focus on oxidatively generated lesions (2017) · cites this paper as [32]
In the citing paper
“solar UV is a potent environmental human carcinogen (10–12).”
From Hypochlorous Acid: From Innate Immune Factor and Environmental Toxicant to Chemopreventive Agent Targeting Solar UV-Induced Skin Cancer (2022) · cites this paper as [12]
Citations
Cites
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Photochemotherapy of Psoriasis with Oral Methoxsalen and Longwave Ultraviolet Light
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Direct and indirect effects of UV radiation on DNA and its components
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Self-citationUltraviolet radiation-mediated damage to cellular DNA
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Self-citationA review of human carcinogens--part D: radiation
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- Kochevar I. E., Bioorganic Photochemistry: Photochemistry and the Nucleic Acids, 273
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Cited by
Sorted by citations
DNA Base Damage by Reactive Oxygen Species, Oxidizing Agents, and UV Radiation
Cadet, J., & Wagner, J. R. (2013) · Cold Spring Harbor Perspectives in Biology · doi:10.1101/cshperspect.a012559 · Cited by 903
Self-citationFormation of UV-induced DNA damage contributing to skin cancer development
Cadet, J., & Douki, T. (2018) · Photochemical & Photobiological Sciences · doi:10.1039/c7pp00395a · Cited by 435
Self-citationSunlight damage to cellular DNA: focus on oxidatively generated lesions
Schuch, A. P., Moreno, N. C., Schuch, N. J., Menck, C. F. M., & Garcia, C. C. M. (2017) · Free Radical Biology and Medicine · doi:10.1016/j.freeradbiomed.2017.01.029 · Cited by 436
Oxidatively Generated Damage to Cellular DNA by UVB and UVA Radiation ,
Cadet, J., Douki, T., & Ravanat, J. (2015) · Photochemistry and Photobiology · doi:10.1111/php.12368 · Cited by 355
Self-citationEarly Events of DNA Photodamage
Schreier, W. J., Gilch, P., & Zinth, W. (2015) · Annual Review of Physical Chemistry · doi:10.1146/annurev-physchem-040214-121821 · Cited by 221
Metadata
- Authors
- Cadet, J., Mouret, S., Ravanat, J., & Douki, T.
- Affiliations
- Université Joseph Fourier (FR)
- Corresponding author
- Cadet, Jean
- Douki, Thierry
- Venue
- Photochemistry and Photobiology
- Publisher
- Wiley
- Published
- 2012-08-30
- Volume
- 88
- Issue
- 5
- Pages
- 1048-1065
- ISSN
- 0031-8655 (ISSN-L)
- 1751-1097
- OpenAlex
- W2090287369
- Semantic Scholar
- 85d02c35f95a00966e70c7fb04d83874dd606a9e
- Cited by
- 300
- References
- 232
- Citations by year
- 2026: 9 · 2025: 13 · 2024: 20 · 2023: 11 · 2022: 19 · 2021: 22 · 2020: 20 · 2019: 17 · 2018: 23 · 2017: 28 · 2016: 34 · 2015: 16 · 2014: 42 · 2013: 25 · 2012: 1
- FWCI
- 2.45
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Photochemistry and Photobiology (publishedVersion)
- PubMed (publishedVersion)
- HAL (submittedVersion)
- Topics
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › DNA Repair Mechanisms
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Cancer Research › Carcinogens and Genotoxicity Assessment
- Health Sciences › Medicine › Dermatology › Skin Protection and Aging
- Keywords
- photoinduced DNA damage, cyclobutane pyrimidine dimers, UVA, UV-B radiation, photodynamic effect, DNA repair, photodamaged skin, mutagenicity
- MeSH terms
- Animals, DNA, DNA Damage, DNA Repair, Cricetinae, Humans, Oxidation-Reduction, Pyrimidine Dimers, Skin, Sunlight, Ultraviolet Rays, Keratinocytes, CHO Cells, Photosensitizing Agents
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
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