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Analysis of bilirubin's relevant photoproducts and their biological significance in the issue of neonatal jaundice
Křepelka, David ; Kozlík, Petr (advisor) ; Zelenka, Jaroslav (referee)
Neonatal jaundice occurs in almost 60% of full-term and 80% of premature babies, where a slightly increased concentration of bilirubin protects against oxidative stress just after birth. When a specific bilirubin level is exceeded in serum (usually above 340 µmol·l-1 ), bilirubin-could induce kernicterus. These negative states are prevented by blue-green light phototherapy (420-510 nm), which converts bilirubin into more polar photoproducts that are more easily excreted via bile and/or urine. Published data have shown that newborns with indicated phototherapy may develop clinical problems later in life (higher incidence of e.g. asthma, allergies, type 1 diabetes was observed at a later age). A possible reason for the occurrence of these diseases is the specific biological activity of photoproducts. This study aims to purify an unknown photoproduct (band P), formed after 8 hours of irradiation of a bilirubin solution with blue light, and to establish a quantitative analytical method for its measurement in relevant matrices. This product was isolated and separated by a thin layer and subsequent column flash chromatography. In the next part, an LC-MS/MS method was developed for quantification of band P. Finally, urine, plasma, and feces samples collected from 15 newborns before and after phototherapy...
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