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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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Study of thiol addition to biliverdine, the synthesis of labelled bilirubine
Felklová, Veronika ; Lešetický, Ladislav (advisor) ; Smrček, Stanislav (referee)
Biliverdin and bilirubin are bile pigments which are degradation products of heme. Biliverdin (BV) is greenish-blue pigment and is reduction product of tetrapyrrolic core of heme by influence of the hemoxygenase (HO). The final product of this degradation is yellowish-brown pigment bilirubin (BR) which forms from BV thanks to the biliverdinreduktase (BVR). Normal and slightly raised level of bilirubin in plasma has cytoprotective effects whereas high levels are cytotoxic often. In severe unconjugated hyperbilirubinemia cases (newborn children) unconjugated bilirubin (UCB) accumulates in central nervous system (CNS) and causes bilirubin-induced neurologic dysfunction (BIND). Unfortunately there is a limitation for finding UCB pathophysiology caused by difficult determination of UCB content and distribution in tissues and biological fluids. So the main purpose of this thesis is to find and integrate isolated methods which will serve as the basis of finding bilirubin distribution. This progress would have a significant effect on studies of bilirubin neurotoxicity on newborn children. This method is based on radioactive labeling of UCB. Preferentially atom C 10 used for binding suitable functional group (thiols) because conformation of indicated bilirubin shouldn't change in this position. And then the...
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Gilbert Syndrome.
Šimáková, Eva ; Kuklík, Miloslav (advisor) ; Kovář, Jan (referee)
This thesis focuses on finding a possible link between genotype typical for Gilberts syndrome and specific diseases. It nvestigates a possible protective effect of the 7TA allele. It explains the origin, symptoms, pathology of this syndrome and its consequences for clinical medicine. Possible protective effect of this polymorphic mutation including reduced incidence of vascular diseases (myocardial infarction, stroke, atherosclerosis, etc.). is discussed. Reduced oxidative stress in hyperbilirubinaemia can be the mechanism behind. The work was carried out in the co-operation with the GENVIA laborator.
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Inherited Disorders of Bilirubin Metabolism
Šlachtová, Lenka ; Martásek, Pavel (advisor) ; Baxová, Alice (referee)
Inherited disorders of bilirubin metabolism - hereditary hyperbilirubinemias - are metabolic disorders manifested in early childhood. Unconjugated hyperbilirubinemias result from the defect of the enzyme uridine diphosphoglucuronosyltransferase (UGT1A1). UGT1A1 mediates the conjugation of bilirubin with glucuronid acid in hepatocytes and its elimination to water soluble compound. In the next step of bilirubin degradation the transport of conjugated bilirubin from hepatocyte into the bile occure. It is caused by the ATP dependent transporters ABCC2, ATP1B1 and OATP1B3. Mutations in the genes coding the bilirubin transporters results in conjugated hyperbilirubinemia Dubin-Johnson or Rotor syndrome. This study is focused on unconjugated hyperbilirubinemia in adolescents including the non-typical manifestations and the defects of ABCC2 transporter and their phenotype in humans.
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Bilirubin secretory pathway and its disorders.
Sticová, Eva ; Jirsa, Milan (advisor) ; Bronský, Jiří (referee) ; Jirásek, Tomáš (referee)
Identification and functional characterization of numerous transport systems at the sinusoidal and canalicular membrane of hepatocytes have significantly expanded our understanding of bilirubin metabolism and contributed to elucidation of molecular basis of hereditary jaundice. Moreover, dysregulation of hepatobiliary transport systems could explain jaundice in many acquired liver disorders. This thesis is focused on the new aspects of bilirubin handling in hepatocytes based on elucidation of the molecular basis of Rotor syndrome. The first study is focused on the antioxidative properties of bilirubin in liver tissue in a model of obstructive cholestasis. In the second part of the thesis we present several novel mutations in ABCC2, the gene associated with Dubin-Johnson syndrome, identified in patients selected for the Rotor locus mapping study. In the key third study concerned with Rotor syndrome we demonstrated that biallelic inactivating mutations causing complete absence of transport proteins OATP1B1 and OATP1B3 result in disruption of hepatic reuptake of bilirubin, which is the molecular basis of Rotor-type jaundice. These results indicate that apart from secretion of conjugated bilirubin into bile, a significant fraction of bilirubin glucuronide is secreted via MRP3 into sinusoidal blood and...
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Antiproliferative effects of heme catabolic pathway's products
Koníčková, Renata ; Vítek, Libor (advisor) ; Haluzík, Martin (referee) ; Farghali, Hassan (referee)
Presented work is focused on heme metabolism with the main interest in bile pigments. Recent data indicate that bilirubin is not only a waste product of the heme catabolic pathway, but also emphasize its important biological impacts, including possible antiproliferative effects. Until today metabolism of bilirubin has not been completely elucidated, which has prevented detailed evaluation of its potential anticancer action. The aim of this study was to clarify some aspects of heme catabolism with respect for antiproliferative properties of its products. Based on the fact that bilirubin potently affects carcinogenesis of the intestine, we initially investigated not properly known bilirubin metabolism by intestinal bacteria. We studied bilirubin neurotoxic effects in hyperbilirubinemic Gunn rats - its distribution in the brain tissue and its degradation during pathological conditions, such as severe newborn jaundice or Crigler-Najjar syndrome. Possible approaches to improve the treatment of severe unconjugated hyperbilirubinemias, combination of the phototherapy and human albumin administration were also investigated. The main reason of these studies was the fact that mechanisms of neurotoxic effects of bilirubin are predominantly identical with those, by which bilirubin inhibits cancer cells growth....
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Antioxidant and antiinflammatory effects of bilirubin.
Valášková, Petra ; Muchová, Lucie (advisor) ; Martínková, Markéta (referee) ; Dvořák, Karel (referee)
For a long time, bilirubin (BR) has been considered a waste molecule with potential toxic effects especially on the central nervous system. Later, it was found that BR exhibited cytoprotective effects and mildly elevated BR levels showed antioxidant, anti-inflammatory and immunomodulatory properties, however, exact mechanisms of the anti-inflammatory actions of BR have not been fully understood yet. The main aim of this study was to assess the protective effects of BR using experimental in vivo and in vitro models in relation to inflammation and oxidative stress. Partial goal was to establish validated analytical method for determination of BR and lumirubin. Gunn and heterozygous rats were treated with lipopolysaccharide (LPS, 6 mg/kg, IP) or vehicle (saline). After 12 hours, blood and organs were collected for analyses of inflammatory and hepatic injury markers. Primary rat hepatocytes were treated with BR and TNF-α, HepG2 and SH-SY5Y cell lines were treated with BR and chenodeoxycholic acid. LPS-treated Gunn rats had a significantly decreased inflammatory response and hepatic injury compared to LPS- treated normobilirubinemic controls. We found different profile of leukocytes subsets and decreased systemic mRNA expressions and concentrations of IL-6, TNF-α, IL-1β and IL-10 in Gunn rats. Hepatic mRNA...
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The nursing care of newborns with Hyperbilirubinaemia
KUCHAŘOVÁ, Petra
This thesis is focused on the nursing care of newborns with neonatal jaundice. Given the focus of the work, the theoretical part describes the newborn, bilirubin, neonatal jaundice, its diagnosis, treatment, nursing care during hospitalization and neonatal care after discharge to home care. The research was conducted with nurses or midwives in the neonatal wards during the months of March and April 2018. A qualitative method was used to conduct the research section. The data collection was conducted through semi-structured interviews. The interviews were conducted after prior arrangement and with the approval of the head nurses. The interview contained 12 open questions. Data analysis was performed by hand coding, also called the pencil and paper method. Responses by individual respondents were identified by codes that were then categorized under different subcategories. As a supplementary method of research, observation was used. It contained 8 open questions and an observation sheet, all of which were done after prior agreement and consent of the mothers of newborns. One goal was set for this thesis: to map the nursing care of newborns with neonatal jaundice. Based on this goal, a research question focused on how midwives and pediatric nurses care for newborns with neonatal jaundice. The research showed that all respondents have an overview of the issue, and that the information they have is subsequently carried out into practice. The results of this research can serve as informative material for midwives and nurses who want to improve their care of newborns with neonatal jaundice, or who are currently preparing to work in this profession.
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Antiproliferative effects of heme catabolic pathway's products
Koníčková, Renata ; Vítek, Libor (advisor) ; Haluzík, Martin (referee) ; Farghali, Hassan (referee)
Presented work is focused on heme metabolism with the main interest in bile pigments. Recent data indicate that bilirubin is not only a waste product of the heme catabolic pathway, but also emphasize its important biological impacts, including possible antiproliferative effects. Until today metabolism of bilirubin has not been completely elucidated, which has prevented detailed evaluation of its potential anticancer action. The aim of this study was to clarify some aspects of heme catabolism with respect for antiproliferative properties of its products. Based on the fact that bilirubin potently affects carcinogenesis of the intestine, we initially investigated not properly known bilirubin metabolism by intestinal bacteria. We studied bilirubin neurotoxic effects in hyperbilirubinemic Gunn rats - its distribution in the brain tissue and its degradation during pathological conditions, such as severe newborn jaundice or Crigler-Najjar syndrome. Possible approaches to improve the treatment of severe unconjugated hyperbilirubinemias, combination of the phototherapy and human albumin administration were also investigated. The main reason of these studies was the fact that mechanisms of neurotoxic effects of bilirubin are predominantly identical with those, by which bilirubin inhibits cancer cells growth....
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