Search results for "Cytochrome"
showing 10 items of 607 documents
Genetic signature consistent with selection against the CYP3A4*1B allele in non-African populations.
2005
Cytochrome P450 3A enzymes (CYP3A) play a major role in the metabolism of steroid hormones, drugs and other chemicals, including many carcinogens. The individually variable CYP3A expression, which remains mostly unexplained, has been suggested to affect clinical phenotypes. We investigated the CYP3A locus in five ethnic groups. The degree of linkage disequilibrium (LD) differed among ethnic groups, but the most common alleles of the conserved LD regions were remarkably similar. Non-African haplotypes are few; for example, only four haplotypes account for 80% of common European Caucasian alleles. Large LD blocks of high frequencies were suggestive of selection. Accordingly, European Caucasia…
Pharmacogenetic Study of ABCB1 and CYP3A5 Genes During the First Year Following Heart Transplantation Regarding Tacrolimus or Cyclosporine Levels
2011
Pharmacogenetics explains part of the interindividual variability in drug responses. Many published works about the effects of single nucleotide polymorphisms (SNPs) on immunosuppressive drug blood levels present contradictory results. We evaluated the SNPs in ABCB1 (glycoprotein P) and CYP3A5 (metabolic enzyme) genes, seeking correlate them with tacrolimus or cyclosporine levels during the first year after heart transplantation. One blood sample was obtained from each of 41 patients: 26 treated with cyclosporine and 15 with tacrolimus. We characterize the SNPs rs1045642, 1128503, 2032582, 2235013, 2235033, 2229109, 3213619, 9282564 in ABCB1 and rs10264272, 776746 in CYP3A5 genes using the …
Molecular phylogeny of the extinct cave lion Panthera leo spelaea.
2004
To reconstruct the phylogenetic position of the extinct cave lion (Panthera leo spelaea), we sequenced 1 kb of the mitochondrial cytochrome b gene from two Pleistocene cave lion DNA samples (47 and 32 ky B.P.). Phylogenetic analysis shows that the ancient sequences form a clade that is most closely related to the extant lions from Africa and Asia; at the same time, cave lions appear to be highly distinct from their living relatives. Our data show that these cave lion sequences represent lineages that were isolated from lions in Africa and Asia since their dispersal over Europe about 600 ky B.P., as they are not found among our sample of extant populations. The cave lion lineages presented h…
Purification of hydroperoxide lyase from green bell pepper (Capsicum annuum L.) fruits for the generation of C6-aldehydes in vitro.
2002
The aim of this work was to compare the efficiency of different extracts of hydroperoxide lyase from green bell peppers in producing aldehydes: a crude extract, a chloroplastic fraction, and a purified enzyme were investigated. From a crude extract, the HPO lyase was purified by ion-exchange chromatography with a 22.3-fold increase in purification factor. Analysis by SDS-PAGE electrophoresis under denaturating conditions showed only one protein with a molecular weight of 55 kDa, whereas size-exclusion chromatography indicated a molecular weight of 170 kDa. A maximum of 7500 mg of aldehydes per g of protein was obtained with the purified enzyme within 20 min of bioconversion compared to 392 …
Transcriptomic Analyses Reveal 2 and 4 Family Members of Cytochromes P450 (CYP) Involved in LPS Inflammatory Response in Pharynx of Ciona robusta
2021
Cytochromes P450 (CYP) are enzymes responsible for the biotransformation of most endogenous and exogenous agents. The expression of each CYP is influenced by a unique combination of mechanisms and factors including genetic polymorphisms, induction by xenobiotics, and regulation by cytokines and hormones. In recent years, Ciona robusta, one of the closest living relatives of vertebrates, has become a model in various fields of biology, in particular for studying inflammatory response. Using an in vivo LPS exposure strategy, next-generation sequencing (NGS) and qRT-PCR combined with bioinformatics and in silico analyses, compared whole pharynx transcripts from naïve and LPS-exposed C. robusta…
Editorial: proton pump inhibitor use in cirrhosis—a piece of the puzzle
2021
No abstract available
Cellular Oxygen Concentration
1976
At low oxygen levels the intracellular or intramitochondrial concentration of molecular oxygen together with the amount of reduced cytochrome oxydase determines the rate of oxygen utilization. Below the so-called “critical oxygen concentration”, i.e. the value, at which a drop in the rate of oxygen uptake has its first evidence, the kinetic is described by the oxygen affinity (Km) of the respiratory chain, i.e. the concentration value for half maximal rate of oxygen uptake.
Potentiation of the antitumor effects of both selective cyclooxygenase-1 and cyclooxygenase-2 inhibitors in human hepatic cancer cells by inhibition …
2007
The molecular mechanisms behind the anti-neoplastic effects of non-steroidal anti-inflammatory drugs (NSAIDs) are not completely understood and cannot be explained by the inhibition of the cyclooxygenase (COX) enzymes COX-1 and COX-2 alone. We previously reported that both the selective COX-1 inhibitor SC-560 and the selective COX-2 inhibitor CAY10404 exhibit anti-tumor effects in human hepatoma cells. NSAID inhibitors have many COX-independent actions and, among others, the mitogen-activated protein kinase (MAPK) pathways are targets for NSAIDs. Here, we examined the role of MEK/ERK1/2 signaling in the anti-neoplastic effects of both selective COX-1 and COX-2 inhibitors in two human hepato…
Down-regulation of human CYP3A4 by the inflammatory signal interleukin-6: molecular mechanism and transcription factors involved.
2002
The hepatic drug-metabolizing cytochrome P-450 (CYP) enzymes are down-regulated during inflammation. In vitro studies with hepatocytes have shown that the cytokines released during inflammatory responses are largely responsible for this CYP repression. However, the signaling pathways and the cytokine-activated factors involved remain to be properly identified. Our research has focused on the negative regulation of CYP3A4 (the major drug-metabolizing human CYP) by interleukin 6 (IL-6) (the principal regulator of the hepatic acute-phase response). CYP3A4 down-regulation by IL-6 requires activation of the glycoprotein receptor gp130; however, it does not proceed through the JAK/STAT pathway, a…
Effect of oxidative stress on UDP-glucuronosyltransferases in rat astrocytes.
2012
WOS:000309170300003; International audience; The present work reports data regarding effects of an induced oxidative stress on the mainly expressed isoforms of UDP-glucuronosyltransferases (UGTs) in the brain. UGT1A6 and UGT1A7 expression and enzymatic activities toward the 1-naphthol were analyzed in rat cultured astrocytes following the exposure for 48 h to redox-cycling xenobiotic compounds such as quinones and bipyridinium ions. The expression of NADPH:cytochrome P450 reductase and NAD(P)H:quinone oxidoreductase 1 (NQO1) was also investigated. Oxidative stress induced significant deleterious changes in astrocyte morphology, decreased cell viability and inhibited catalytic function of UG…