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Effect of broad and narrow spectrum fluorescent light on blood constituents
Insights
Phototherapy using blue light reduces riboflavin and can cause hemolysis in infants, indicating broader biological effects beyond bilirubin reduction. These photochemical effects suggest light penetrates deeper than the skin.
Area of Science:
- Biochemistry
- Neonatal Medicine
- Photochemistry
Background:
- Phototherapy is a standard treatment for hyperbilirubinemia in infants.
- Blue fluorescent light is commonly used for phototherapy.
- Potential side effects of phototherapy require further investigation.
Purpose of the Study:
- To determine the effects of broad and narrow spectrum blue light on riboflavin, G-6-PD activity, and plasma amino acids in infants.
- To investigate the biological impacts of phototherapy beyond its primary function.
Main Methods:
- Measurement of whole blood riboflavin levels.
- Assay of erythrocyte glucose-6-phosphate dehydrogenase (G-6-PD) activity.
- Analysis of plasma amino acid concentrations in infants undergoing phototherapy.
Main Results:
- Both broad and narrow spectrum blue light reduced riboflavin levels.
- Some infants exhibited G-6-PD activity loss and subsequent hemolysis (in vivo and in vitro).
- A reduction in plasma amino acids was observed under broad spectrum light, but not narrow spectrum light.
Conclusions:
- Phototherapy with fluorescent light sources induces significant biological effects beyond hyperbilirubinemia reduction.
- The observed hemolysis may be linked to indirect effects of riboflavin reduction, not direct enzyme impact.
- Phototherapy light penetrates beyond superficial skin layers, causing photochemical effects.
Abstract:
Riboflavin in whole blood, G-6-PD activity in erythrocytes and amino acids in plasma of infants irradiated by broad and narrow spectrum blue fluorescent light were determined. Riboflavin was reduced by both types of light. Loss of G-6-PD activity during phototherapy with subsequent hemolysis was observed in some infants under each type of light source, both in vivo and in vitro. This phenomenon may be related to the indirect effect of riboflavin reduction and not to a direct effect upon the enzyme. The reduction of the plasma concentration of some amino acids observed under broad spectrum irradiation but not under pure blue light may not be of significance, but is of concern. These data indicate that all fluorescent light sources in current use for phototherapy produce biologic effects of importance beside the primary purpose of the treatment to reduce hyperbilirubinemia. It is apparent from the results of these studies that phototherapy light penetrates more deeply than the superficial skin to exert photochemical effects.