Urinary Thymidine Dimer as a Marker of Total Body Burden of UV-Inflicted DNA Damage in Humans

DOI: 10.1158/1055-9965.EPI-05-0164 Published December 2005

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Figure 1.
³²P-HPLC chromatogram of thymine dimer (T = T). A, 10 fmol of T = T standard after photoreversion to parental dinucleotide followed by ³²P-postlabeling (³²pTpT). B, 10 fmol of T = T postlabeled directly without photoreversion. C, urine sample collected before solarium tanning. D. Urine sample collected 1 day after tanning (peak contains 4.3 fmol of ³²pTpT).
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Figure 2.
Kinetic of urinary thymine dimer (T = T) excretion after UV irradiation as mean values (± SD) for 10 persons during 20 to 30 minutes of solarium use. Time 0 represents the T = T level in samples taken just before the tanning session. The data for each day are expressed as a percentage of the total amount of T = T and compared statistically (t test) with day 3 (*, P < 0.05; **, P < 0.01; ***, P < 0.001).
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Figure 3.
Cumulative thymine dimer (T = T) levels after UV irradiation for the six volunteers who were followed up to 11 days. Time 0 represents the T = T level in samples taken just before the tanning session.

Table 1.

Amounts of urinary thymine dimer (T = T) after UV irradiation in a solarium and the rates for its excretion

Volunteer	Sex	Dose (J/m²)	Amount of T = T*, (nmol)	Amount of T = T (pmol per m² body surface area per J/m²)	50% excretion time^† (hours)
1	F	383	3.6	5.8	69
2	F	256	3.3	9.0	62
3	F	124	1.9	9.3	70
4	F	256	3.4	7.4	65
5	F	383	2.4	3.6	70
6	F	383	2.9	4.6	55
7	M	383	5.5	7.2	75
8	M	192	2.9	6.6	71
9	F	383	2.0	3.5	64
10	M	383	1.6	2.0	76

↵* Total amount of T = T for 5 days assuming an average excretion of 160 μmol creatinine per kg body weight per day for women and 200 μmol for men (10).
↵† The 50% excretion time was calculated from the excretion rate during the first 5 days following UV irradiation.

Table 2.

Relative amounts of urinary thymine dimer excreted for 5 days following different UV sessions in a solarium

NOTE: The data for session A were taken from the fourth column of Table 1 (volunteer 8 participated only in session A and was therefore not included). For session B, the exposure time was 50% of that in session A. For session C, the upper part of the solarium was covered resulting in 50% of the body being exposed. Sessions A and B were repeated once.