scispace - formally typeset
Search or ask a question
Author

Claude C. Roy

Bio: Claude C. Roy is an academic researcher from Université de Montréal. The author has contributed to research in topics: Cystic fibrosis & Bile acid. The author has an hindex of 40, co-authored 122 publications receiving 6627 citations. Previous affiliations of Claude C. Roy include University of Colorado Boulder & Columbia University.


Papers
More filters
Journal ArticleDOI
TL;DR: This one-step direct transesterification procedure carried out in methanol-benzene 4:1 with acetyl chloride is superior to currently used methods not onlyBecause of its simplicity and speed, but also because of its added precision.

2,315 citations

Journal ArticleDOI
TL;DR: Prebiotics seem to be largely mediated by SCFA, but evidence from human studies remains inconsistent, and the food industry is making a leap of faith in their efforts to commercialize prebiotics and exploit potential health benefits.
Abstract: The concept of colonic health has become a major target for the development of functional foods such as probiotics, prebiotics, and synbiotics. These bioactive agents have a profound effect on the composition of the microflora, as well as on the physiology of the colon, and display distinct health benefits. Dietary carbohydrates escaping digestion/absorption in the small bowel and prebiotics undergo fermentation in the colon and give rise to short-chain fatty acids (SCFA). As the main anions of the colon and the major source of energy for colonocytes, SCFA are rapidly absorbed by nonionic diffusion mostly but also by active transport mediated by a sodium-coupled transporter, thereby fostering the absorption of sodium and water. SCFA in general and butyrate in particular enhance the growth of lactobacilli and bifidobacteria and play a central role on the physiology and metabolism of the colon. The effect of prebiotics on cell proliferation, differentiation, apoptosis, mucin production, immune function, mineral absorption, lipid metabolism, and gastrointestinal (GI) peptides has been well documented experimentally. These effects seem to be largely mediated by SCFA, but evidence from human studies remains inconsistent. The food industry is making a leap of faith in their efforts to commercialize prebiotics and exploit potential health benefits. The future lies with the design of studies to further explore basic mechanisms, and gene expression in particular, but emphasis should be placed on human intervention trials.

364 citations

Journal ArticleDOI
TL;DR: The data suggest that chylomicrons, which vastly exceed the size of typical COPII vesicles, are selectively recruited by the COPII machinery for transport through the secretory pathways of the cell.
Abstract: Dietary fat is an important source of nutrition. Here we identify eight mutations in SARA2 that are associated with three severe disorders of fat malabsorption. The Sar1 family of proteins initiates the intracellular transport of proteins in COPII (coat protein)-coated vesicles. Our data suggest that chylomicrons, which vastly exceed the size of typical COPII vesicles, are selectively recruited by the COPII machinery for transport through the secretory pathways of the cell.

364 citations

Journal ArticleDOI
TL;DR: Preparative steps led to the detection of a single peak that on spectral analysis was identified as pure MDA-TBA, and this procedure offers several advantages in terms of specificity, recovery, and reproducibility.

166 citations

Journal ArticleDOI
TL;DR: The specificity of the methylation reaction for NEFA without hydrolysis of other classes of plasma lipids was substantiated with appropriate standards and this one-step specific methylation procedure is superior to currently used methods.

162 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: This review summarizes the role of SCFAs in host energy metabolism, starting from the production by the gut microbiota to the uptake by the host and ending with the effects on host metabolism.

3,040 citations

Journal ArticleDOI
TL;DR: Findings show that in the context of a dietary pattern that includes high fat consumption, BCAA contributes to development of obesity-associated insulin resistance.

2,611 citations

Journal ArticleDOI
23 Jan 2004-Cell
TL;DR: Genetic and biochemical analyses of the secretory pathway have produced a detailed picture of the molecular mechanisms involved in selective cargo transport between organelles, including Vesicle budding and cargo selection, which depend on a machinery that includes the SNARE proteins.

1,713 citations

Journal ArticleDOI
TL;DR: The specific RET codon mutation correlates with the MEN2 syndromic variant, the age of onset of M TC, and the aggressiveness of MTC; consequently, that mutation should guide major management decisions, such as whether and when to perform thyroidectomy.
Abstract: This is a consensus statement from an international group, mostly of clinical endocrinologists. MEN1 and MEN2 are hereditary cancer syndromes. The commonest tumors secrete PTH or gastrin in MEN1, and calcitonin or catecholamines in MEN2. Management strategies improved after the discoveries of their genes. MEN1 has no clear syndromic variants. Tumor monitoring in MEN1 carriers includes biochemical tests yearly and imaging tests less often. Neck surgery includes subtotal or total parathyroidectomy, parathyroid cryopreservation, and thymectomy. Proton pump inhibitors or somatostatin analogs are the main management for oversecretion of entero-pancreatic hormones, except insulin. The roles for surgery of most entero-pancreatic tumors present several controversies: exclusion of most operations on gastrinomas and indications for surgery on other tumors. Each MEN1 family probably has an inactivating MEN1 germline mutation. Testing for a germline MEN1 mutation gives useful information, but rarely mandates an intervention. The most distinctive MEN2 variants are MEN2A, MEN2B, and familial medullary thyroid cancer (MTC). They vary in aggressiveness of MTC and spectrum of disturbed organs. Mortality in MEN2 is greater from MTC than from pheochromocytoma. Thyroidectomy, during childhood if possible, is the goal in all MEN2 carriers to prevent or cure MTC. Each MEN2 index case probably has an activating germline RET mutation. RET testing has replaced calcitonin testing to diagnose the MEN2 carrier state. The specific RET codon mutation correlates with the MEN2 syndromic variant, the age of onset of MTC, and the aggressiveness of MTC; consequently, that mutation should guide major management decisions, such as whether and when to perform thyroidectomy.

1,685 citations

Journal ArticleDOI
01 Jul 2009-Diabetes
TL;DR: Dietary supplementation of butyrate can prevent and treat diet-induced insulin resistance in mouse and the mechanism ofbutyrate action is related to promotion of energy expenditure and induction of mitochondria function.
Abstract: OBJECTIVE We examined the role of butyric acid, a short-chain fatty acid formed by fermentation in the large intestine, in the regulation of insulin sensitivity in mice fed a high-fat diet. RESEARCH DESIGN AND METHODS In dietary-obese C57BL/6J mice, sodium butyrate was administrated through diet supplementation at 5% wt/wt in the high-fat diet. Insulin sensitivity was examined with insulin tolerance testing and homeostasis model assessment for insulin resistance. Energy metabolism was monitored in a metabolic chamber. Mitochondrial function was investigated in brown adipocytes and skeletal muscle in the mice. RESULTS On the high-fat diet, supplementation of butyrate prevented development of insulin resistance and obesity in C57BL/6 mice. Fasting blood glucose, fasting insulin, and insulin tolerance were all preserved in the treated mice. Body fat content was maintained at 10% without a reduction in food intake. Adaptive thermogenesis and fatty acid oxidation were enhanced. An increase in mitochondrial function and biogenesis was observed in skeletal muscle and brown fat. The type I fiber was enriched in skeletal muscle. Peroxisome proliferator–activated receptor-γ coactivator-1α expression was elevated at mRNA and protein levels. AMP kinase and p38 activities were elevated. In the obese mice, supplementation of butyrate led to an increase in insulin sensitivity and a reduction in adiposity. CONCLUSIONS Dietary supplementation of butyrate can prevent and treat diet-induced insulin resistance in mouse. The mechanism of butyrate action is related to promotion of energy expenditure and induction of mitochondria function.

1,593 citations