Publications by authors named "Jean Morisset"

This review article has primary objective to summarize pancreatic research which has been done in our laboratory since 1965, the first year of the author's registration in the Ph.D. program at the University of Sherbrooke (Canada).

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This review article has for major main objectives to give an overlook of the major physiological effects of somatostatin on different organs. It will cover first the general aspect of the hormone, its cDNA and its protein maturation process, as well as its characterization in various organs. This aspect will be followed by the factors involved in the control of its secretion, its intracellular mode of action, and its general action on physiological processes.

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This review article has 4 major objectives to follow pancreatic physiology development more than close to 70 years of intensive and productive basic research. At first, the review will focus on secretion of the pancreatic enzymes with (1) the controls involved, (2) the interrelations existing between secretion and synthesis of these enzymes, (3) the enzymes' adaptation to the constituents of the diet, and (4) whether secretion of the different enzymes is parallel or nonparallel. Second, growth and regeneration of the pancreatic gland will be looked at in relation to the factors involved and the target cells implicated.

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Background & Aims: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in combination with cytopathology is the optimal method for diagnosis and staging of pancreatic ductal adenocarcinoma (PDAC) and other pancreatic lesions. Its clinical utility, however, can be limited by high rates of indeterminate or false-negative results. We aimed to develop and validate a microRNA (miRNA)-based test to improve preoperative detection of PDAC.

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Background: Physiology of the exocrine pancreas has been well studied in domestic and in laboratory animals as well as in humans. However, it remains quite unknown in wildlife mammals. Roe deer and cattle (including calf) belong to different families but have a common ancestor.

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Bone morphogenetic protein (BMP) signaling within the gastrointestinal tract is complex. BMP ligands and their receptors are expressed in both epithelial and mesenchymal compartments, suggesting bidirectional signaling between these two entities. Despite an increasing interest in BMP signaling in gut physiology and pathologies, the distinct contribution of BMP signaling in the epithelium vs.

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With the exclusive presence of the pancreatic CCK-2 receptors on the pancreatic delta cells of six different species, this study was undertaken to determine the role of cholecystokinin and gastrin on growth of these somatostatin (SS) cells. For this study, the SS-RIN-14B cells were used in culture and their growth was evaluated by cell counting. Results.

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Objectives: This study evaluated the role played by cholecystokinin (CCK) receptors' occupation in the control of somatostatin (SS) secretion in RIN-14B cells.

Methods: The presence of the CCK receptors 1 and 2 was confirmed by immunofluorescence, and SS secretion was evaluated by enzyme-linked immunosorbent assay.

Results: By immunofluorescence, 95% of the cell population was composed of SS cells bearing both CCK-R subtypes with 5% of beta cells (data not shown).

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The negative control of pancreatic exocrine secretion in man occurs during the interdigestive and postprandial periods of the digestive cycle. The physiological mechanisms involved include negative feedback mechanisms, well described and accepted in animals, and controlled by the cholecystokinin- and secretin-releasing factors of pancreatic and duodenal origin, along with the active pancreatic proteases present in the upper gut. The presence of these factors and their efficacy in humans, however, have their supporters and detractors, with a possibility for reconciliation among opponents.

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We interview Dr. Jean Morisset, an internationally recognized leader in the field of pancreatic physiology. His work on the regulation of pancreatic secretion by hormones and the parasympathetic nervous system has been fundamental to the understanding of pancreatic adaptation to diet in normal as well as pathological conditions.

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Objective: To measure concentrations and activities of major digestive enzymes in healthy equine pancreatic tissue.

Animals: 7 adult horses with normal pancreatic tissues.

Procedures: Small pieces of pancreatic tissue were collected immediately after euthanasia, immersed in liquid nitrogen, and maintained at -80 degrees C until analyzed.

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A differential allele-specific accumulation of kappa-casein mRNA that is not linked to the kappa-casein protein variants is described in Holstein cows. Actually, cows genotyped kappa-casein AB were a mixed population. For the first group of kappa-casein AB cows, allele A-specific kappa-casein mRNA contents within mammary epithelial cells were lower than the allele B-specific ones (cows LH), suggesting that the allele A-specific kappa-casein gene was expressed with lower efficiency in mRNA.

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The objectives of this review are to summarize, analyse and discuss the roles played by the CCK receptor subtypes and their agonists on pancreatic enzyme secretion, pancreas growth and regeneration, define the receptors specific target cells and evaluate the role of gastrin in pancreatic pathologies including cancer. In rodents, it is clear that the CCKARs present on pancreatic acinar cells play a major role in enzyme secretion. In large mammals, CCK does not seem to be the final mediator of enzyme release.

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This study was undertaken to show that rat purified islets can be used as a reliable tool to study some aspects of human islet's physiology related to CCKR occupation. Therefore, isolated foetal, adult human and rat islets were compared for (1) CCKR subtypes mRNA and protein expression and somatostatin (SS) mRNA and (2) co-localization of these receptors with insulin, glucagon and SS. Finally, rat islets were tested for their responsiveness to stimulation.

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The cholecystokinin B receptor (CCK(B)R) is localized on pancreatic endocrine somatostatin delta-cells. Pancreatic somatostatin content was increased in diabetic rats. The mechanisms involved in this phenomenon are unknown, and we believe insulin is involved.

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This study was undertaken to clarify the controversy in the literature about pancreatic localization of the cholecystokinin (CCK) CCK(A) and CCK(B) receptors. With antibodies used by other investigators, we first established their specificity by Western blotting, indirect immunofluorescence, and confocal microscopy with each antibody's peptide antigen. Co-localization assays between the CCK receptors and the pancreatic hormones insulin, glucagon, and somatostatin revealed that the CCK(A) RAbs 1122 and R1-2 recognized insulin and glucagon cells in rat, pig, and human pancreas but not in the somatostatin cells.

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Neutrophil homeostasis was investigated in two mouse lines, AIRmax and AIRmin, genetically selected for high or low acute inflammatory response (AIR) and compared with unselected BALB/c mice. Mature neutrophil phenotype and functions appeared similar in the three mouse lines. However, an unprecedented phenotype was revealed in AIRmax animals characterized by a high neutrophil production in bone marrow (BM), a high number of neutrophils in blood, a high concentration of chemotactic agents in acrylamide-induced inflammatory exudates, and an increased resistance of locally infiltrated neutrophils to spontaneous apoptosis.

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This study was undertaken to confirm the presence of CCK receptor subtypes in calf pancreas and establish their cellular localization. Using specific antibodies against CCKA and CCKB receptors, somatostatin, glucagon and insulin, we were able to confirm by Western blot the presence of both CCK receptor protein subtypes in the calf pancreas as a 80-85-kDa CCKA receptor and 40-45-kDa CCKB receptor. By immunofluorescence, the CCKB receptor colocalizes with the islets' somatostatin delta cells, confirming what was previously shown in other species, as well as on ductal cells.

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The aim of this study was to evaluate pancreatic juice secretion of calves in the first postnatal days, and determine a potential involvement of cholecystokinin (CCK) and intestinal CCK receptor in its regulation. Nine neonatal Friesian calves (five controls and four treated intraduodenally with FK480, a CCK-A receptor antagonist) were surgically fitted with a pancreatic duct catheter and a duodenal cannula before the first colostrum feeding. Collections of pancreatic juice and duodenal luminal pressure recordings were started early after recovery from anaesthesia and continued for 6 days.

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