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Lai Kit Ching Jan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 121-141). / Abstracts in English and Chinese. / Abstract --- p.i / 摘要 --- p.iv / Acknowledgements --- p.vi / List of abbreviations --- p.vii / List of figures --- p.ix / Table of contents --- p.xi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- "The structure, function and regulation of growth hormone" --- p.1 / Chapter 1.2 --- Historical perspective of growth hormone secretagogues --- p.5 / Chapter 1.3 --- Ghrelin and growth hormone secretagogue receptor --- p.7 / Chapter 1.4 --- Calcium signalling of growth hormone secretagogues --- p.12 / Chapter 1.5 --- Pancreas and functions of exocrine pancreas --- p.15 / Chapter 1.6 --- Regulation of exocrine pancreatic function --- p.22 / Chapter 1.7 --- Functions of ghrelin in pancreas --- p.32 / Chapter 1.8 --- Aims of study --- p.34 / Chapter Chapter 2 --- Materials and methods --- p.35 / Chapter 2.1 --- Experimental animal and cell line models --- p.35 / Chapter 2.1.1 --- Rat model --- p.35 / Chapter 2.1.2 --- Isolation of pancreatic lobules and acinar cells --- p.35 / Chapter 2.1.3 --- Omeprazole-induced gastric acid inhibition --- p.36 / Chapter 2.1.4 --- Cerulein-induced acute pancreatitis --- p.37 / Chapter 2.1.5 --- Starvation rat model --- p.37 / Chapter 2.1.6 --- AR42J cell line --- p.38 / Chapter 2.2 --- Reverse transcriptase-polymerase chain reaction --- p.39 / Chapter 2.2.1 --- Total RNA extraction and quantification --- p.39 / Chapter 2.2.2 --- Reverse transcription --- p.40 / Chapter 2.2.3 --- Polymerase chain reaction --- p.40 / Chapter 2.2.4 --- Gel electrophoresis --- p.41 / Chapter 2.2.5 --- Optimization of semi-quantitative RT-PCR --- p.42 / Chapter 2.3 --- Western blot analysis --- p.43 / Chapter 2.3.1 --- Extraction of total protein and quantification --- p.43 / Chapter 2.3.2 --- Sodium Dodecyl-sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE) --- p.43 / Chapter 2.3.3 --- Tricine Sodium Dodecyl-sulphate Polyacrylamide Gel Electrophoresis (Tricine-SDS-PAGE) --- p.44 / Chapter 2.3.4 --- Electroblotting and immunodetection of proteins --- p.45 / Chapter 2.4 --- Immunocytochemistry --- p.47 / Chapter 2.4.1 --- Preparation of isolated acinar cells for paraffin sections --- p.47 / Chapter 2.4.2 --- Preparation of AR42J cells slices --- p.47 / Chapter 2.4.3 --- Immunofluorescent double staining --- p.47 / Chapter 2.5 --- Functional studies of digestive enzyme secretion from pancreatic isolated acini and lobules --- p.49 / Chapter 2.5.1 --- Incubation of pancreatic isolated acini and lobules with different peptides --- p.49 / Chapter 2.5.2 --- Quantification of protein content --- p.50 / Chapter 2.5.3 --- Measurement of a-amylase secretion by α-amylase assay --- p.50 / Chapter 2.6 --- Spectrofluorimetric measurement --- p.52 / Chapter 2.6.1 --- Incubation of AR42J cells with Fluo-4/AM --- p.52 / Chapter 2.6.2 --- Pretreatment of antagonist or blockers and Ca2+-free treatment --- p.52 / Chapter 2.6.3 --- Calcium mobilization assay --- p.53 / Chapter 2.7 --- Statistics and data analysis --- p.54

Exocrine pancreatic insufficiency (EPI) is a major complication of cystic fibrosis. Conventional treatment involves the replacement of pancreatic enzymes and intake of a low fat diet. However, contrary to previous therapeutic strategies, a high fat diet may be beneficial in EPI patients. The present study investigated the effects of dietary supplementation with Creon 10 000 a pancreatic enzyme preparation, in conjunction with a high-fat diet, on growth performance, digestibility and absorption of fat in a pig model of EPI by the surgical ligation of the pancreatic duct in 6 male pigs (Swedish Landrace X Yorkshire X Hampshire). Following surgery, and for the duration of the experimental period, pigs were fed a high fat diet (twice daily). The experimental period lasted for 15 days during which blood, urine and faecal samples were collected. In the last 7 days of the experimental period (days 8-14), Creon 10 000 was included in the high fat meals. Urine and faecal samples were analysed for dry matter, crude protein and fat content. Plasma was used to assess the lipaemic index and the plasma lipid profiles. Treatment with Creon 10 000 significantly increased body mass (P = 0.016) and the digestibility of dry matter, crude protein as well as the co-efficient of fat absorption were also significantly improved following treatment (P<0.05). Creon 10 000 improved the lipaemic index values and significant changes in plasma free fatty acid and triglyceride concentrations were observed but not in cholesterol or high and low density lipoproteins. This study supports previous reports that the administration of pancreatic enzyme preparations together with a high fat meal is a beneficial strategy for the nutritional management of EPI.

Poly- and perfluoroalkyl substances (PFAS) are a class of bioaccumulative toxicants used in numerous industrial and commercial products. Perfluorooctanesulfonic acid (PFOS) alters pancreatic organogenesis during development, and perfluorohexanesulfonic acid (PFHxS) has been suggested as a replacement for PFOS due to its shorter carbon chain, but they are often found together in surfactants, such as legacy aqueous film-forming foam. This study investigates how developmental exposures to a PFAS mixture (PFHxS + PFOS) impact the developing exocrine pancreas. Zebrafish embryos (Tg(ptf1a:GFP)) were exposed to 0.01% DMSO, or 8, 16, 32 μM PFHxS alone, 16 μM PFOS alone, and 8, 16, and 32 μM PFHxS plus 16 μM PFOS. Embryos underwent refreshing exposures (3 hours post fertilization (hpf) - 96 hpf) or static exposures (3, 24, 48, or 72 hpf - 96 hpf) and then live imaging to quantify the truncated exocrine pancreas phenotype that occurred, and at what point in development it became apparent. PFAS mixtures significantly impacted growth parameters and exocrine pancreas length. The truncated pancreas phenotype was seen most often in the 16 μM PFHxS + 16 μM PFOS treatment group, so this concentration was used for subsequent experiments. Time lapse imaging (58 - 72 hpf, 80 - 96 hpf) and cellular proliferation assays (3 - 96 hpf) were used to ascertain the cause of the truncated phenotype as an issue of cellular migration or proliferation within the pancreas. Cell migration and proliferation were decreased in response to toxicant exposure. This study offers insights to how developmental exposures to toxicants may impact the pancreas.

Ce travail scientifique a abordé la problématique de la communication cellulaire entre le pancréas exocrine et endocrine dans la mucoviscidose. La contribution des infections pulmonaires chroniques et des traitements immunosuppresseurs sur la dégénerescence pancréatique a été aussi étudiée. Les résultats obtenus ont montré que le LPS disséminé par des infections récurrentes peut cibler les cellules pancréatiques exocrines, en conduisant à la formation des microparticules membranaires qui sont nuisibles pour la survie et le fonctionnement des cellules endocrines. Dans cette communication intercellulaire, la protéine CFTR est un médiateur essentiel de la sévérité des signaux délivrés par les microparticules et de la réponse cellulaire à l'inflammation du pancréas, en participant à l'équilibre de la sécrétion d'insuline des cellules endocrines. En outre, les données ont mis en évidence que l'administration prolongée d’immunosuppresseurs chez les patients greffés pourrait différemment induire l'apoptose de manière dépendante de la mitochondrie, cela en favorisant l'entrée des cellules en sénescence prématurée, un état métabolique du dysfonctionnement cellulaire. / This scientific work tackled the issue of the communication between exocrine and endocrine pancreas in cystic fibrosis. Also, the contribution of recurrent lung infections and immunosuppressive therapy to the pancreatic cell degenerescence was studied in vitro. Results obtained showed that disseminated LPS released by recurrent infections could target pancreatic exocrine cells, leading to the formation of membrane microparticles that are deleterious for endocrine cell survival and function. In this intercellular cross-talk, CFTR is a critical mediator for the severity of the MP-delivered signals and for the pancreatic cell response to inflammation, also participating to the balance of insulin secretion of endocrine cells. Furthermore, data evidenced that long-term administration of immunosuppressive drugs in grafted patients may differently induce apoptosis in a mitochondrial-dependent fashion, possibly favoring cells to enter premature senescence, which is a metabolic state of cellular dysfunction.

No description available.

Thesis (MSc)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: Please refer to fulltext for abstract / AFRIKAANSE OPSOMMING: Sien asb volteks vir opsomming

Thesis (MSc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Bontebok, Damaliscus pygargus pygargus, formerly classified as D. dorcas dorcas, are territorial animals with interdigital glands between the toes of the forelegs. Males regularly defecate on dung heaps, on which they often lie, to communicate with other members of their species. They also communicate by means of visual displays, scent marking and occasionally with scraping or pawing of dung heaps. It is assumed that scent marking with the interdigital secretion serves to define territories frequented by these antelope. These glands secrete a complex mixture of volatile and non-volatile compounds and the volatile compounds in the secretion serve as a chemical signal for other bontebok. It has been suggested that the interdigital secretion is not produced in its final composition by the interdigital gland alone, but that microbial activity is responsible for many of the compounds present in the secretion. In general, many compounds can be attributed to the by-products of microbial hydrolysis of triglycerides, a common characteristic of sebum. It is well documented that micro-organisms inhabit the deep recesses of sebaceous glands and the presence of micro-organisms has been found to be consistent in all antelope exocrine glandular areas. This study involved the chemical characterisation of the volatile metabolites produced in vitro by micro-organisms from the interdigital cavity of the bontebok. Various comparative studies were made, one of which was comparison of the metabolites produced by the individual microbial species as well as the total community of bacteria incubated in different media. A comparison of the compounds identified in the interdigital secretion and the metabolites produced by the micro-organisms in the different media was also made. The volatile metabolite extracts of the individual bacterial species and of the total community were chemically characterised by low-resolution gas chromatography-mass spectroscopy. Classes of compounds identified from the volatile metabolite extracts include: • Acids - Aliphatic (saturated and unsaturated) • Alcohols - Aliphatic (saturated and unsaturated) • Aldehydes - Aliphatic (saturated and unsaturated) • Aromatic compounds • Ketones - Aliphatic (saturated and unsaturated) • Pyrazines • Dimethyldisulphide • Squalene and cholesterol Several qualitative differences were found between the compounds identified in the volatile metabolite extracts of the micro-organisms when incubated in tryptic soy broth (TSB) and minimal salt medium (MSM). In particular, when the microbes were incubated in TSB medium a number of pyrazines were found that were not present when utilising MSM as a medium. Additional qualitative differences were found between the compounds identified in the metabolite extracts of the individual bacterial species and the total community of bacteria, when incubated in both TSB and MSM media. A comparison of the interdigital secretion and the metabolite extracts of the microbial communities incubated in TSB and MSM revealed that many compounds produced in MSM corresponded to the compounds identified in the interdigital secretion. These corresponding compounds were found to be saturated and unsaturated acids, aldehydes and squalene. Furthermore, there was only one corresponding compound in the case of TSB as medium. / AFRIKAANSE OPSOMMING: Die bontebok, Damaliscus pygargus pygargus, voorheen geklassifiseer as D. dorcas dorcas, is 'n territoriale dier met interdigitale kliere tussen die kloutjies van die voorpote. Ramme ontlas gereeld op mishope, waarop hulle dikwels lê, om met ander lede van die spesie te kommunikeer. Hulle kommunikeer ook deur middel van visuele seine, reukmerking en soms deur mishope met die voorpote te kap of te skraap. Reukmerking met die interdigitale afskeiding dien klaarblyklik om gebiede wat deur hierdie diere bewoon word, af te baken. Die interdigitale kliere skei 'n komplekse mengsel van vlugtige en nie-vlugtige verbindings af en die vlugtige verbindings dien as chemiese sein vir ander bontebokke. Die vermoede bestaan dat die interdigitale klier nie alleen verantwoordelik is vir die finale samestelling van die interdigitale afskeiding nie, maar dat mikrobiese aktiwiteit bydra tot die produksie van baie van die verbindings wat in die afskeiding aanwesig is. Sekere verbindings kan in die algemeen toegeskryf word aan die vorming van die neweprodukte van mikrobiese hidrolise van trigliseriede, 'n algemene eienskap van sebum. Dit is bekend dat die diep holtes van vetkliere 'n goeie teelaarde is vir mikroorganismes en daar is gevind dat mikroorganismes feitlik deurgaans voorkom in alle anteloop eksokriene klierareas. Hierdie studie behels die chemiese karakterisering van die vlugtige metaboliete wat in vitro deur mikroorganismes van die interdigitale klierholte van die bontebok geproduseer word. Verskeie vergelykende studies is uitgevoer waarvan een die vergelyking was van die metaboliete wat deur die individuele mikrobiese spesies sowel as die totale gemeenskap van bakterieë geproduseer word tydens inkubasie in verskillende media. Vergelyking van die verbindings wat in die interdigitale afskeiding geïdentifiseer is met die metaboliete wat in verskillende media geproduseer is, het ook deel van die studie uitgemaak. Die vlugtige metaboliet ekstrakte van die individuele bakteriese spesies en van die totale gemeenskap is chemies gekarakteriseer deur middel van laeresolusie gaschromatografie-massaspektrometrie. Die volgende groepe verbindings is onder andere in die vlugtige metaboliet ekstrakte geïdentifiseer: • Sure - Alifaties (versadig en onversadig) • Alkohole - Alifaties (versadig en onversadig) • Aldehiede - Alifaties (versadig en onversadig) • Aromatiese verbindings • Ketone - Alifaties (versadig en onversadig) • Pirasiene • Dimetieldisulfied • Skwaleen en cholesterol Verskeie kwalitatiewe verskille is gevind tussen die verbindings wat geïdentifiseer is in die vlugtige metaboliet ekstrakte van die mikroorganismes onderskeidelik in TSB medium en MSM geïnkubeer. Opvallend was byvoorbeeld die voorkoms van pirasiene in gevalle waar mikroorganismes in TSB medium geïnkubeer is, terwyl hierdie groep verbindings afwesig was wanneer MSM gebruik is. Onderlinge kwalitatiewe verskille is ook gevind tussen die verbindings wat geïdentifiseer is in die metaboliet ekstrakte van die individuele bakteriese spesies en die totale gemeenskap van bakterieë, wanneer in TSB medium sowel as in MSM geïnkubeer is. Vergelyking van die verbindings in die interdigitale afskeiding en in die metaboliet ekstrakte van die mikrobiese gemeenskappe, het getoon dat 'n aantal verbindings wat in MSM geproduseer is, ooreenstem met verbindings wat in die interdigitale afskeiding geïdentifiseer is. Daar is gevind dat hierdie verbindings versadigde en onversadigde sure en aldehiede en skwaleen is. Met TSB as medium was daar slegs een ooreenstemmende verbinding.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.