Abstract
Conventional cytogenetic techniques have failed to detect chromosome breakage in infants due to phototherapy. Sister chromatid exchange (SCE) analysis now permits a more sensitive examination of the impact of bilirubin plus light on human chromosomes. In vitro exposure of adult lymphocytes to 20 mg/dl bilirubin, 2 × 105 J/m2 white fluorescent light, or to both resulted in 16.6, 17.8, or 17.0 SCE/cell, respectively; levels not significantly greater than the control of 17.2 SCE/cell (54-61 cells per value, all cultures 1% DMSO). In vivo response was examined in a double-blind study of 9 premature infants, 5 undergoing phototherapy (35 ± 8.4h) and 4 controls matched for wt. (1531 ± 375g), age (30-35 wks. gestation) and serum bilirubin (7.5 ± 1.7 mg/dl). The pre- and post-treatment SCE frequencies in the treated group (8.2 - 11.7 and 7.1 - 10.7/cell, approx. 20 cells examined per infant) did not differ significantly either between themselves or from parallel measurements on controls (9.0 - 11.7 and 7.7 - 11.6/cell), and chromosomal breakage was negligible in all cases. Our results differ from those of a differently designed study (Lancet 2: 1084, 1977) which observed increased SCE frequency due to phototherapy. Interindividual variations in SCE in our study were significant, and infant SCE frequencies were significantly lower than those typical for untreated adult cells (15.5 ± 0.2/cell). Our present data provide evidence that phototherapy does not demonstrably alter SCE frequency in premature infants.
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Schwartz, A., Cole, F., Fiedorek, F. et al. 1022 PHOTOTHERAPY DOES NOT INCREASE THE SISTER CHROMATID EXCHANGE FREQUENCY IN PREMATURE INFANTS. Pediatr Res 12 (Suppl 4), 534 (1978). https://doi.org/10.1203/00006450-197804001-01028
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DOI: https://doi.org/10.1203/00006450-197804001-01028