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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Application of Artificial Gel Antibodies for the Detection and Quantification of Proteins in Biological Fluids

Ghasemzadeh, Nasim January 2010 (has links)
The molecular-imprinting method has previously been used for the synthesis of artificial gel antibodies, highly selective for various proteins. In present study, we have synthesized artificial gel antibodies against haemoglobin, albumin and different forms of growth hormone with the aim to develop a simple and rapid procedure to measure the concentration of these protein biomarkers in samples of clinical interest.  A spectrophotometric method was developed to design a standard curve in the form of a straight line, whereby the true absorption (not the recorded “apparent” absorption) was plotted against a known protein concentration. The procedure, applied to quantitative analysis of albumin in human plasma and cerebrospinal fluid (CSF) from patients with ALS, indicated that  the concentration of this protein was significantly enhanced in CSF from patients with amyotrophic lateral sclerosis (ALS), compared to control samples. A low level of albumin was observed in plasma from ALS patients compared to controls. Additionally, free zone electrophoresis was employed to detect human growth hormone (GH) activity in hormone preparations purified from human pituitaries. We have successfully synthesized antibodies capable of discriminating between dimeric and monomeric GH in samples of clinical origin. To quantify these proteins a calibration curve has been designed, i.e. a plot of the electrophoretic mobility of the complex GH/gel antibody against the protein concentration in the sample, for instance serum or CSF. This method was also employed for qualitative and quantitative determinations of Somatropin, a non-glycosylated GH and glycosylated-GH in a body liquid. Our results indicate that by this technique one can “fish out” with high accuracy various proteins from both body fluids containing a great number of other proteins. It might well apply also to biomarker proteins for other diseases.
2

Cytochrome P450 Enzymes in Bile Acid Biosynthesis and Fatty Acid Metabolism : Studies on Members of the Porcine CYP4A and CYP8B Subfamilies

Lundell, Kerstin January 2003 (has links)
<p>The present investigation is devoted to studies on porcine members of the cytochrome P450 4A (CYP4A) and CYP8B1 subfamilies, which are involved in bile acid biosynthesis and fatty acid metabolism. </p><p>Hyocholic acid is considered to fulfil the requirements for trihydroxy bile acids in the domestic pig (Sus scrofa) in the absence of cholic acid. Hyocholic acid is a 6α-hydroxylated product of chenodeoxycholic acid and the enzyme catalyzing the 6α-hydroxylation was cloned and found to be an atypical member of the CYP4A subfamily. The primary structure of this porcine enzyme, designated CYP4A21, shows about 75% overall sequence identity to members of the CYP4A subfamily expressed in rabbit and man. Divergent amino acids in a “signature sequence” in the active site of all hitherto known CYP4A fatty acid hydroxylases, were found to be important determinants for the 6α-hydroxylase activity of CYP4A21. </p><p>Two homologous CYP4A fatty acid hydroxylases, designated CYP4A24 and CYP4A25, expressed in pig liver and kidney were cloned. These two cDNAs encode proteins of 504 amino acids similar to CYP4A21. The overall identity between CYP4A24 and CYP4A25 is 97% compared to 94% identity to CYP4A21. Whereas CYP4A21 clearly deviates regarding structural features and catalytic activity it is more difficult to establish whether CYP4A24 and CYP4A25 are distinct enzymes or allelic variants of a single enzyme. </p><p>Cloning of the CYP4A21 gene showed a conserved organization compared to CYP4A genes in other species. A segment of the CYP4A24 gene was also cloned and comparison with the CYP4A21 gene revealed an extensive sequence identity also within introns as well as within the proximal promoter regions. This indicates that CYP4A21 and CYP4A fatty acid hydroxylases have a common origin and evolved by gene duplication. The CYP4A21 and CYP4A fatty acid hydroxylases, however, show distinct patterns of expression.</p><p>The key enzyme in cholic acid biosynthesis, CYP8B1, was markedly expressed in fetal pig liver compared to livers from young pigs. The opposite was shown for the expression of CYP4A21. An apparently conserved pig CYP8B1 gene was cloned and was intronless, similar to CYP8B1 genes from other species. The pig gene encoded a protein of 501 amino acids with 81% identity to CYP8B1 expressed in rabbit and man. Unlike other CYP8B1 genes, the pig promoter lacked a TATA-box. This might offer one explanation for the unusual expression pattern, which appears to be restricted to pig fetal life.</p>
3

Expression of Genes Encoding for Drug Metabolism in the Small Intestine

Lindell, Monica January 2003 (has links)
<p>This investigation focused on the mRNA expression of drug metabolising Cytochromes P-450 (CYP) and UDP-glucuronosyltransferases (UGT) and the transport protein P-glycoprotein (Pgp) in the small intestine of humans and rats.</p><p>The mRNA expression of the investigated genes in the human small intestine (duodenum) varies between individuals giving each one of us personal profile. In general, the most dominant forms are Pgp, CYPs 2C9, 2D6, 3A4, and UGTs 1A1, 1A10, 2B7. However, which of these is the highest expressed one varies between individuals.</p><p>The correlation in expression between some CYP forms and UGT forms respectively is relatively high, which indicates that they have some regulatory mechanisms in common. It was also shown that the mRNA expression of both CYPs and UGTs may be affected by endogenous and exogenous factors. Sex and ethnic background, affected the mRNA expression of CYP2A6 and 2E1 respectively. Commonly used drugs such as acetylsalicylicacid (ASA) and omeprazole (omep) affect CYP2A6, CYP2E1 (ASA) and CYP3A4, UGT1A4 (omep). The expression of UGT1A4 is also affected by smoking. All these factors are commonly used and can therefore lead to important drug-drug interactions.</p><p>It was also shown that the human small intestinal CYP mRNA expression pattern differs from that found in the rat. The rat CYP expression is rather constant between the different individuals, and the main rat intestinal forms are CYP1A1, CYP2C, CYP2D6 and CYP3A1. The expression is the same for females and males and no difference can be seen between the different segments of the rat small intestine. As metabolic studies have often been done with rat liver we compared the mRNA expression in the two organs. We found that the mRNA expression of 1A1 was absent in the liver and that the CYP2B1, CYP2Cs, CYP2D1 and Pgp all had a stronger mRNA expression in the small intestine compared to the liver. It is therefore important to realise that results from metabolic studies on liver may not be directly extrapolated to the small intestine.</p><p>Artemisinin is an orally used drug in multidrug treatment of malaria in Southeast Asia. It has been suggested that artemisinin can induce drug metabolism and therefore be involved in drug-drug interactions. This study shows that artemisinin induces mainly the CYP2B via nuclear receptor CAR.</p>
4

Cytochrome P450 Enzymes in Bile Acid Biosynthesis and Fatty Acid Metabolism : Studies on Members of the Porcine CYP4A and CYP8B Subfamilies

Lundell, Kerstin January 2003 (has links)
The present investigation is devoted to studies on porcine members of the cytochrome P450 4A (CYP4A) and CYP8B1 subfamilies, which are involved in bile acid biosynthesis and fatty acid metabolism. Hyocholic acid is considered to fulfil the requirements for trihydroxy bile acids in the domestic pig (Sus scrofa) in the absence of cholic acid. Hyocholic acid is a 6α-hydroxylated product of chenodeoxycholic acid and the enzyme catalyzing the 6α-hydroxylation was cloned and found to be an atypical member of the CYP4A subfamily. The primary structure of this porcine enzyme, designated CYP4A21, shows about 75% overall sequence identity to members of the CYP4A subfamily expressed in rabbit and man. Divergent amino acids in a “signature sequence” in the active site of all hitherto known CYP4A fatty acid hydroxylases, were found to be important determinants for the 6α-hydroxylase activity of CYP4A21. Two homologous CYP4A fatty acid hydroxylases, designated CYP4A24 and CYP4A25, expressed in pig liver and kidney were cloned. These two cDNAs encode proteins of 504 amino acids similar to CYP4A21. The overall identity between CYP4A24 and CYP4A25 is 97% compared to 94% identity to CYP4A21. Whereas CYP4A21 clearly deviates regarding structural features and catalytic activity it is more difficult to establish whether CYP4A24 and CYP4A25 are distinct enzymes or allelic variants of a single enzyme. Cloning of the CYP4A21 gene showed a conserved organization compared to CYP4A genes in other species. A segment of the CYP4A24 gene was also cloned and comparison with the CYP4A21 gene revealed an extensive sequence identity also within introns as well as within the proximal promoter regions. This indicates that CYP4A21 and CYP4A fatty acid hydroxylases have a common origin and evolved by gene duplication. The CYP4A21 and CYP4A fatty acid hydroxylases, however, show distinct patterns of expression. The key enzyme in cholic acid biosynthesis, CYP8B1, was markedly expressed in fetal pig liver compared to livers from young pigs. The opposite was shown for the expression of CYP4A21. An apparently conserved pig CYP8B1 gene was cloned and was intronless, similar to CYP8B1 genes from other species. The pig gene encoded a protein of 501 amino acids with 81% identity to CYP8B1 expressed in rabbit and man. Unlike other CYP8B1 genes, the pig promoter lacked a TATA-box. This might offer one explanation for the unusual expression pattern, which appears to be restricted to pig fetal life.
5

Expression of Genes Encoding for Drug Metabolism in the Small Intestine

Lindell, Monica January 2003 (has links)
This investigation focused on the mRNA expression of drug metabolising Cytochromes P-450 (CYP) and UDP-glucuronosyltransferases (UGT) and the transport protein P-glycoprotein (Pgp) in the small intestine of humans and rats. The mRNA expression of the investigated genes in the human small intestine (duodenum) varies between individuals giving each one of us personal profile. In general, the most dominant forms are Pgp, CYPs 2C9, 2D6, 3A4, and UGTs 1A1, 1A10, 2B7. However, which of these is the highest expressed one varies between individuals. The correlation in expression between some CYP forms and UGT forms respectively is relatively high, which indicates that they have some regulatory mechanisms in common. It was also shown that the mRNA expression of both CYPs and UGTs may be affected by endogenous and exogenous factors. Sex and ethnic background, affected the mRNA expression of CYP2A6 and 2E1 respectively. Commonly used drugs such as acetylsalicylicacid (ASA) and omeprazole (omep) affect CYP2A6, CYP2E1 (ASA) and CYP3A4, UGT1A4 (omep). The expression of UGT1A4 is also affected by smoking. All these factors are commonly used and can therefore lead to important drug-drug interactions. It was also shown that the human small intestinal CYP mRNA expression pattern differs from that found in the rat. The rat CYP expression is rather constant between the different individuals, and the main rat intestinal forms are CYP1A1, CYP2C, CYP2D6 and CYP3A1. The expression is the same for females and males and no difference can be seen between the different segments of the rat small intestine. As metabolic studies have often been done with rat liver we compared the mRNA expression in the two organs. We found that the mRNA expression of 1A1 was absent in the liver and that the CYP2B1, CYP2Cs, CYP2D1 and Pgp all had a stronger mRNA expression in the small intestine compared to the liver. It is therefore important to realise that results from metabolic studies on liver may not be directly extrapolated to the small intestine. Artemisinin is an orally used drug in multidrug treatment of malaria in Southeast Asia. It has been suggested that artemisinin can induce drug metabolism and therefore be involved in drug-drug interactions. This study shows that artemisinin induces mainly the CYP2B via nuclear receptor CAR.
6

The Multifunctional HnRNP A1 Protein in the Regulation of the <i>Cyp2a5</i> Gene : Connecting Transcriptional and Posttranscriptional Processes

Glisovic, Tina January 2003 (has links)
<p>The mouse xenobiotic-inducible <i>Cyp2a5</i> gene is both transcriptionally and posttranscriptionally regulated. One of the most potent <i>Cyp2a5</i> inducers, the hepatotoxin pyrazole, increases the CYP2A5 mRNA half-life. The induction is accomplished through the interaction of a pyrazole-inducible protein with a 71 nt long, putative hairpin-loop region in the 3' UTR of the CYP2A5 mRNA.</p><p>The aims of this thesis have been to identify the pyrazole-inducible protein, to investigate its role in the <i>Cyp2a5</i> expression and the significance of the 71 nt hairpin-loop region for the <i>Cyp2a5</i> expression, and to examine a possible coupling between transcriptional and posttranscriptional processes in <i>Cyp2a5</i> expression.</p><p>The pyrazole-inducible protein was identified as the heterogeneous nuclear ribonucleoprotein (hnRNP) A1. Studies performed in mouse primary hepatocytes overexpressing hnRNP A1, and in mouse erythroleukemia derived cells lacking hnRNP A1, revealed that the 71 nt region in the 3' UTR of the CYP2A5 mRNA is essential for <i>Cyp2a5</i> expression.</p><p>The hnRNP A1 is a multifunctional nucleocytoplasmic shuttling protein, with the ability to bind both RNA and DNA. These properties make it an interesting candidate mediating a coupling between nuclear and cytoplasmic gene regulatory events, which was investigated for the <i>Cyp2a5</i>. In conditions of cellular stress hnRNP A1 translocates from the nucleus to the cytoplasm. The accumulation of cytoplasmic hnRNP A1 after RNA polymerase II transcription inhibition, resulted in an increased binding of hnRNP A1 to the CYP2A5 mRNA, parallel with a stabilization of the CYP2A5 mRNA.</p><p>Treating primary mouse hepatocytes with phenobarbital (PB), a <i>Cyp2a5</i> transcriptional inducer, resulted in a mainly nuclear localization of the hnRNP A1. Electrophoretic mobility shift assays with nuclear extracts from control or PB-treated mice, revealed that hnRNP A1 interacts with two regions in the <i>Cyp2a5</i> proximal promoter, and that the interaction to one of the regions was stimulated by PB treatment.</p><p>In conclusion, the change in hnRNP A1 subcellular localization after transcriptional inhibition or activation, together with the effects on the interaction of hnRNP A1 with the CYP2A5 mRNA and <i>Cyp2a5</i> promoter, suggest that hnRNP A1 could couple the nuclear and cytoplasmic events of the <i>Cyp2a5</i> expression.</p><p>The presented studies are the first showing involvement of an hnRNP protein in the regulation of a <i>Cyp</i> gene. Moreover, it is the first time an interconnected transcriptional and posttranscriptional regulation has been suggested for a member of the <i>Cyp</i> gene family.</p>
7

The Multifunctional HnRNP A1 Protein in the Regulation of the Cyp2a5 Gene : Connecting Transcriptional and Posttranscriptional Processes

Glisovic, Tina January 2003 (has links)
The mouse xenobiotic-inducible Cyp2a5 gene is both transcriptionally and posttranscriptionally regulated. One of the most potent Cyp2a5 inducers, the hepatotoxin pyrazole, increases the CYP2A5 mRNA half-life. The induction is accomplished through the interaction of a pyrazole-inducible protein with a 71 nt long, putative hairpin-loop region in the 3' UTR of the CYP2A5 mRNA. The aims of this thesis have been to identify the pyrazole-inducible protein, to investigate its role in the Cyp2a5 expression and the significance of the 71 nt hairpin-loop region for the Cyp2a5 expression, and to examine a possible coupling between transcriptional and posttranscriptional processes in Cyp2a5 expression. The pyrazole-inducible protein was identified as the heterogeneous nuclear ribonucleoprotein (hnRNP) A1. Studies performed in mouse primary hepatocytes overexpressing hnRNP A1, and in mouse erythroleukemia derived cells lacking hnRNP A1, revealed that the 71 nt region in the 3' UTR of the CYP2A5 mRNA is essential for Cyp2a5 expression. The hnRNP A1 is a multifunctional nucleocytoplasmic shuttling protein, with the ability to bind both RNA and DNA. These properties make it an interesting candidate mediating a coupling between nuclear and cytoplasmic gene regulatory events, which was investigated for the Cyp2a5. In conditions of cellular stress hnRNP A1 translocates from the nucleus to the cytoplasm. The accumulation of cytoplasmic hnRNP A1 after RNA polymerase II transcription inhibition, resulted in an increased binding of hnRNP A1 to the CYP2A5 mRNA, parallel with a stabilization of the CYP2A5 mRNA. Treating primary mouse hepatocytes with phenobarbital (PB), a Cyp2a5 transcriptional inducer, resulted in a mainly nuclear localization of the hnRNP A1. Electrophoretic mobility shift assays with nuclear extracts from control or PB-treated mice, revealed that hnRNP A1 interacts with two regions in the Cyp2a5 proximal promoter, and that the interaction to one of the regions was stimulated by PB treatment. In conclusion, the change in hnRNP A1 subcellular localization after transcriptional inhibition or activation, together with the effects on the interaction of hnRNP A1 with the CYP2A5 mRNA and Cyp2a5 promoter, suggest that hnRNP A1 could couple the nuclear and cytoplasmic events of the Cyp2a5 expression. The presented studies are the first showing involvement of an hnRNP protein in the regulation of a Cyp gene. Moreover, it is the first time an interconnected transcriptional and posttranscriptional regulation has been suggested for a member of the Cyp gene family.
8

Hormonal Regulation of the Human CYP27A1 and CYP7B1 Genes

Tang, Wanjin January 2007 (has links)
<p>CYP27A1 and CYP7B1 are widely expressed in various human tissues and are two key enzymes involved in the pathways for conversion of cholesterol to bile acids. Also, CYP27A1 is involved in bioactivation of vitamin D3 and CYP7B1 plays a role in 7alpha-hydroxylation of dehydroepiandrosterone and other steroids. Both enzymes have been reported to be relevant to prostate cell proliferation. The current study examines the hormonal regulation of CYP27A1 and CYP7B1.</p><p>CYP7B1 was shown to be regulated by estrogens and androgens in human embryonic kidney HEK293 and prostate cancer LNCaP cells. Quantitation of CYP7B1 mRNA in adult and fetal human tissues showed markedly higher CYP7B1 mRNA levels in fetal tissues compared with the corresponding adult ones, except in the liver. This indicates a tissue-specific, developmental regulation of CYP7B1 and suggests an important function for this enzyme in fetal life. CYP7B1 regulation by estrogens may be of importance in fetal development and in other processes where CYP7B1 is involved, including cholesterol homeostasis, cellular proliferation, and CNS function. The regulation of CYP7B1 by sex hormones also suggests an important role for CYP7B1 in balancing prostate hormone levels in human cells. </p><p>Results show that CYP27A1 can be regulated by dexamethasone, growth hormone, IGF-1, PMA, estrogens and androgens in liver-derived HepG2 cells. Dexamethasone, growth hormone and IGF-1 stimulated the promoter and endogenous activity of CYP27A1, whereas thyroid hormones and PMA inhibited CYP27A1. The regulatory effects of estrogens and androgens are different depending on the cell types. Thus, the results imply that human CYP27A1 gene is a target for estrogens and androgens, and the expression of CYP27A1 may be affected by endogenous sex hormones and pharmacological compounds with estrogenic or androgenic effects. </p><p>The mechanism for the dexamethasone-induced effect on the human CYP27A1 promoter was examined. A GRE was identified important for GR-mediated regulation of CYP27A1 transcriptional activity. </p>
9

Hormonal Regulation of the Human CYP27A1 and CYP7B1 Genes

Tang, Wanjin January 2007 (has links)
CYP27A1 and CYP7B1 are widely expressed in various human tissues and are two key enzymes involved in the pathways for conversion of cholesterol to bile acids. Also, CYP27A1 is involved in bioactivation of vitamin D3 and CYP7B1 plays a role in 7alpha-hydroxylation of dehydroepiandrosterone and other steroids. Both enzymes have been reported to be relevant to prostate cell proliferation. The current study examines the hormonal regulation of CYP27A1 and CYP7B1. CYP7B1 was shown to be regulated by estrogens and androgens in human embryonic kidney HEK293 and prostate cancer LNCaP cells. Quantitation of CYP7B1 mRNA in adult and fetal human tissues showed markedly higher CYP7B1 mRNA levels in fetal tissues compared with the corresponding adult ones, except in the liver. This indicates a tissue-specific, developmental regulation of CYP7B1 and suggests an important function for this enzyme in fetal life. CYP7B1 regulation by estrogens may be of importance in fetal development and in other processes where CYP7B1 is involved, including cholesterol homeostasis, cellular proliferation, and CNS function. The regulation of CYP7B1 by sex hormones also suggests an important role for CYP7B1 in balancing prostate hormone levels in human cells. Results show that CYP27A1 can be regulated by dexamethasone, growth hormone, IGF-1, PMA, estrogens and androgens in liver-derived HepG2 cells. Dexamethasone, growth hormone and IGF-1 stimulated the promoter and endogenous activity of CYP27A1, whereas thyroid hormones and PMA inhibited CYP27A1. The regulatory effects of estrogens and androgens are different depending on the cell types. Thus, the results imply that human CYP27A1 gene is a target for estrogens and androgens, and the expression of CYP27A1 may be affected by endogenous sex hormones and pharmacological compounds with estrogenic or androgenic effects. The mechanism for the dexamethasone-induced effect on the human CYP27A1 promoter was examined. A GRE was identified important for GR-mediated regulation of CYP27A1 transcriptional activity.
10

Post-Transcriptional Regulation of the Murine Inducible Nitric Oxide Synthase Gene

Söderberg, Malin January 2005 (has links)
<p>Large amounts of nitric oxide (NO) are produced by the inducible nitric oxide synthase (iNOS) upon inflammatory stimuli. NO is a multifaceted molecule, which may have beneficial effects as an antimicrobial agent in the immune defense, or cytotoxic effects in chronic inflammations, manifested as e.g. arthritis and asthma. Understanding the mode of regulation of the iNOS gene is a prerequisite for developing intervention strategies in various pathological conditions where detrimental effects of NO need to be prevented.</p><p>Transcriptional processes of the iNOS gene regulation are well described, while post-transcriptional events have not been studied in detail. The aim of the present thesis was to investigate post-transcriptional regulatory mechanisms involving the 3’untranslated region (UTR) of the murine iNOS mRNA.</p><p>Inflammation-dependent RNA-protein interactions with the iNOS mRNA 3’UTR were characterized by RNA gel shift analysis and UV cross-linking. <i>Trans</i>-acting factors interacting with the 3’UTR were detected in mouse liver and macrophages and identified as heterogeneous nuclear ribonucleoproteins (hnRNP) I and L. Western blot revealed that reduced hnRNPI levels are responsible for the decreased interaction of hnRNPI with iNOS 3’UTR upon induction in inflammatory conditions. This decrease was reversed by the glucocorticoid dexamethasone, concomitant with decreased iNOS mRNA levels and stability. Introduction of the iNOS 3’UTR into a luciferase reporter gene reduced its expression in macrophages. Upon deletions of the binding sites for hnRNPI and hnRNPL, the luciferase expression was recovered. In addition, inflammatory stimuli increased the luciferase activity of the construct with the full-length 3’UTR, while only weak effects of the stimuli were seen on the deletion constructs.</p><p>In conclusion, the results suggest that binding of hnRNPI and hnRNPL to the iNOS mRNA 3’UTR promotes degradation of the transcript. Induction of iNOS by inflammatory stimuli dissociates the RNA-protein complex, yielding a more stable mRNA. In addition, post-transcriptional down-regulation of the iNOS gene by the anti-inflammatory glucocorticoid dexamethasone, seems to involve hnRNPI.</p>

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