Does intensive phototherapy produce hemolysis in newborns of 35 or more weeks gestation?

Maisels, M. Jeffrey; Kring, Elizabeth

doi:10.1038/sj.jp.7211552

Cited by 11 publications

(2 citation statements)

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“…Other in vitro studies have demonstrated cellular consequences of phototherapy, specifi cally, the ability to modify cellular DNA with the potential of mutagenic or carcinogenic changes [30][31][32] . In contrast, in vivo studies of healthy, term neonates exposed to phototherapy administered under clinical conditions, have not demonstrated evidence of hemolysis or lipid peroxidation [27,[33][34][35][36][37] . Apparent discrepancies between these in vitro and in vivo studies may be attributable, in part, to the unreliability of hematological indices as indicators of hemolysis in newborns, because of overlap in parameters between hemolytic and non-hemo- [38] .…”

Section: Discussionmentioning

confidence: 99%

Phototherapy and Photo-Oxidation in Premature Neonates

et al. 2005

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Objective: The potential for photo-oxidation during phototherapy in premature neonates was assessed by measuring parameters reflective of photo-oxidation. Methods: Blood was sampled from premature neonates prior to, and after 4 and 24 h of phototherapy, respectively. Total plasma bilirubin (TPB), blood carboxyhemoglobin corrected for inspired carbon monoxide (COHbc) (a sensitive index of heme catabolism), blood thiobarbituric acid reacting substances (TBARS) (a measure of lipid peroxidation), and plasma protein carbonyls (representative of protein oxidation) were determined. Study measurements were compared with baseline values both for the entire study group, and also individually for subgroups < and ≧1.5 kg birthweight, respectively. The percentage difference (%δ) between baseline and the 24-hour measurement was calculated for each parameter. Results: Forty-one premature neonates (mean [± SD] gestational age 30.5 ± 2.7 weeks and birthweight 1,499 ± 448 g) were studied. Mean TPB values decreased from a baseline of 9.1 ± 2.3 to one of 7.2 ± 2.8 mg/dl, p < 0.01, during the first 24 h of phototherapy. For the entire patient sample, neither COHbc, TBARS or protein carbonyl values increased significantly over baseline measurements: COHbc: 0.90 ± 0.26% vs. 0.92 ± 0.32%; TBARS: 19.0 ± 5.6 vs. 18.0 ± 4.5 nmol/ml, and protein carbonyls 7.73 ± 3.78 vs. 7.63 ± 3.56 U/ml (baseline and 24-hour samples only are shown in the abstract). Similarly, for the entire group, %δ (mean, interquartile range) were not significantly different between COHbc [–3.77 (–15.89–17.65)%], TBARS [–7.47 (–17.37–7.38)%], and protein carbonyls [–1.47 (–28.51–43.48)%], respectively. For subgroup analysis of neonates < or ≧ 1.5 kg birthweight, respectively, no significant increases in COHbc, TBARS or protein carbonyls were documented. A significant increase in %δ for COHbc in the <1.5 kg birthweight subgroup compared with those ≧1.5 kg, possibly indicative of hemolysis, was not matched by similar changes in %δ for TBARS or protein carbonyls, and may therefore not be a result of photo-oxidation. Conclusions: Except for changes in %δ in COHbc alone and in the smallest babies only, overall, short term phototherapy in premature infants was effective in reducing TPB concentrations without associated evidence reflective of photo-oxidation.

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Section: Discussionmentioning

confidence: 99%

Phototherapy and Photo-Oxidation in Premature Neonates

et al. 2005

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“…However, rash extrapolations from in vitro studies to real life have previously muddied the waters of bilirubin metabolism and led, for example, to suggestions that photodegradation of bilirubin is the most important pathway in phototherapy and that photohemolysis might be a significant adverse effect of the treatment, suggestions now thought to be incorrect. 44,45 It seems to have gone unnoticed that bilirubin has the characteristics of a promiscuous inhibitor. [46][47][48] Promiscuous inhibitors are compounds that lead to false-positive results in the high-throughput screening of potential drugs in vitro.…”

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confidence: 99%