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Biomedical subjects

C C Roy

Publications and source records attributed to C C Roy.

At least 91 records · Page 5Linked to original sources
PubMed1984

Lithocholic acid-cholesterol interactions in rat liver plasma membrane fractions.

This study was designed to elucidate the steps involved in the incorporation of lithocholic acid and the increase in cholesterol in liver plasma membranes after lithocholic acid injection. In vitro, cholesterol incorporation or binding to liver plasma membrane fractions enriched in bile canalicular structures occurred only when cholesterol was added simultaneously with lithocholic acid. The addition of cholic acid did not prevent the incorporation or binding of lithocholic acid and of cholesterol. However, when cholic acid was incubated with membranes already containing lithocholic acid and cholesterol, the ratio of cholesterol to lithocholic acid increased from 2 to more than 3 via a reduction of lithocholic acid. The binding of lithocholic acid and cholesterol to membranes rose 5-fold in the presence of cytosolic proteins. By electron microscopy the canalicular membrane structures with a high cholesterol content exhibited few microvilli, and their lumen appeared to have collapsed. These data suggest that simultaneous interaction of lithocholic acid and cholesterol, and not prior incorporation or binding of lithocholic acid to the membrane, may be a prerequisite to cholesterol accumulation in the membrane.

Animals↗
PubMed1984

Improved recovery of fatty acid through direct transesterification without prior extraction or purification.

Methods currently in use for the quantitative measurement of fatty acids by gas-liquid chromatography after transesterification are usually lengthy and cumbersome. The technique described is a one-step reaction that is carried out in the same tube and bypasses all the extraction and purification steps. Recoveries of fatty acid and triglyceride standards (C6:0 to C24:1) were better than 96%. When the direct transesterification method was compared to the Folch extraction procedure, increases of fatty acid concentration of 11.4% and 15.8% were observed in human milk and adipose tissue, respectively. The method appears to be particularly advantageous for the recovery of the highly volatile medium chain triglycerides and there is no need to add an antioxidant to protect unsaturated lipids.

Adipose Tissue↗
PubMed1984

The composition of preterm milk in relation to the degree of prematurity.

Fifty-one samples of 24-h milk collections obtained during the 1st month of lactation from mothers who delivered after gestations of 26 to 31 wk (VPT) contained higher concentrations of nitrogen (297 +/- 11 mg/dl), total fatty acids (4.46 +/- 0.17 g/dl), percentage medium chain fatty acids (10.8 +/- 0.7), and energy (78.3 +/- 2.0 kcal/dl) than either or both those from 32 to 36 wk (PT) and term (T) gestations. PT collections did not differ from T milk with regard to nitrogen (250 +/- 13 versus 259 +/- 13), total fatty acids (3.94 +/- 0.20 versus 3.20 +/- 0.30), percentage medium chain fatty acids (9.1 +/- 0.5 versus 8.1 +/- 0.7) and energy (69.0 +/- 2.7 versus 66.6 +/- 2.4). Although postpartum age (5 to 10 versus 11 to 30 days) did not change the nutrient and energy content of VPT, PT, and T collections, it is only in 11 to 30 day VPT milk that nitrogen and energy content became higher (p less than 0.05) than either or both PT and T milk. We conclude that the differences in macronutrient composition of PT milk are limited to VPT milk and the data from repeated milk collections in the same mother (28 wk) suggest that there is considerable variability in its composition.

Amino Acids↗
PubMed1983

Taurine prevents cholestasis induced by lithocholic acid sulfate in guinea pigs.

The hypothesis that the amino acid used for the conjugation of sulfolithocholate (S-LCA) is a critical determinant of its cholestatic potential was tested in the guinea pig which conjugates 90% of its bile acids with glycine. Twelve groups of animals were used to study the effect of taurine feeding at a concentration of 0.5% in the drinking water for periods of 1, 3, and 5 days before an iv injection of 18 mumol/100 g body weight of S-LCA. Bile flow was monitored in 30-min aliquots over a 3-h period and the bile acid secretion as well as the glycine/taurine ratio of conjugated bile acids were determined. At the end of the various time periods, the livers were examined by light and electron microscopy. Within 3 days after taurine administration there was an increase in bile flow and a reversal of the glycine/taurine ratio with taurine conjugates becoming predominant. Liver morphology was unchanged except for a slight accumulation of lipids after 5 days of taurine feeding. In animals who were not pretreated with taurine, S-LCA injection led to a progressive decrease in bile flow such, that it was reduced to less than 20% at the end of the 3-h collection. S-LCA was conjugated almost exclusively with glycine. In contrast, in the groups fed taurine for 1, 3, and 5 days before the S-LCA injection, bile flow was comparable to that of the groups fed taurine alone. The S-LCA recovered in bile was to a large extent conjugated with taurine. S-LCA animals pretreated with taurine did not exhibit any liver cell changes while the group which had not received taurine before the S-LCA injection showed numerous cytoplasmic vacuoles with normal bile canaliculi. These data show that increasing the availability of taurine through dietary means may exert a protective effect against cholestasis induced by monohydroxy bile acids.

Animals↗
PubMed1983

Effect of diversion of pancreatic secretions on biliary lipids and bile salt kinetics in the rat.

The hypothesis that the absence of pancreatic secretions from the lumen of the intestinal tract could alter the secretion rate of biliary lipids and the kinetics of bile salts was tested in rats with a pancreatic fistula fed intragastrically either a high or a low fat liquid diet over a 4-day period. In animals with external derivation of all pancreatic secretions who were given the high fat diet, stools were pale and bulky, the basal synthesis rate of bile acids was almost twice that of controls, and there was an increase in the secretion rate of cholesterol and phospholipids calculated from the first 2 h of bile collection. On the low fat diet, there was no change in basal bile salt synthesis, but the pool was larger and the secretion rate of bile acids and phospholipids was increased. A study of the quantitative relationship between the excretion rate of phospholipids and of cholesterol to that of bile acids following complete biliary diversion revealed a disproportionately large output of cholesterol at low bile acid flow rates under both diets in rats with a pancreatic fistula. These data suggest that experimental pancreatic insufficiency leads to alterations of the secretion rate of biliary lipids and to uncoupling of the close relationship between bile acids and cholesterol.

Animals↗
PubMed1983

Relapsing pancreatitis in association with Crohn's disease.

Two adolescent girls, aged 15 and 18, in whom the diagnosis of Crohn's ileocolitis had been made 6 months and 3 years previously, developed acute pancreatitis with relapses of varying duration and severity. The younger patient's condition progressed to chronic relapsing pancreatitis with intractable pain despite partial pancreatectomy. The other has had recurrent acute attacks but has been well between bouts. No duodenal involvement could be found in the two cases and there was no evidence to implicate drugs as a factor responsible for this rare association between pancreatitis and Crohn's disease.

Acute Disease↗
PubMed1982

Influence of cultural and environmental factors on breast-feeding.

A study was undertaken at hôpital Sainte-Justine, Montreal, to determine the factors that influence the choice of feeding method for infants and the duration of breast-feeding. The factors that most clearly distinguished the mothers who breast-fed were lifestyle, education and conditioning to the parental role; those who nursed successfully for a long time were well motivated, well educated, supported by their family, especially the husband, and the La Leche League, and were of an economic status such that it was not necessary for them to return to work soon after delivery. Although the breast-fed babies were more fussy, they were healthier and received fewer drugs.

Bottle Feeding↗
PubMed1982

Hepatobiliary disease in cystic fibrosis: a survey of current issues and concepts.

The incidence of hepatobiliary complications of cystic fibrosis (CF) has been increasing in parallel with the rate of survival. Detection of hepatic involvement remains a problem, as liver function tests, serum bile acid determinations, and ultrasonography do not permit an early diagnosis. The pathogenesis of cholelithiasis has been elucidated in the past few years. However, the mechanism leading to the pathognomonic CF lesion, focal biliary cirrhosis, is still unknown. There are indications that mucus plugging may be the ancestral lesion and the triggering factor. The possibility that correction of the abnormalities of bile acid metabolism could slow the progress or prevent CF cirrhosis is discussed in light of recent experimental data.

Adolescent↗
PubMed1981

Severe familial cholestasis in North American Indian children: a clinical model of microfilament dysfunction?

Studies of 14 North American Indian children with a familial type of severe neonatal cholestasis are described. Jaundice occurred during the neonatal period in 9 children, but disappeared before the end of the 1st yr. Progressive liver damage was documented by the persistence of high levels of alkaline phosphatase, moderate elevation of transaminases, and severe pruritus. Serum bile acids were constantly elevated (3.0-119.5 microgram/ml). Early portal hypertension and variceal bleeding necessitated portal-systemic shunts in 7 children. By light microscopy, the early stage was characterized by hepatitis with giant-cell transformation and biliary stasis. Later on, portal fibrosis became evident and was followed by cirrhosis. By electron microscopy bile canaliculi appeared slightly dilated with preservation or only partial loss of microvilli. They were surrounded by a prominent pericanalicular filamentous web. Immunofluorescence studies indicated the presence of action-containing microfilaments. This group of children might represent a human model of microfilament dysfunction-induced cholestasis.

Actins↗