Resistance of insulin to insulinase. A genetic discriminant in diabetes mellitus.
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Biomedical subjects
Publications and source records attributed to C C Roy.
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Although immaturity of the liver and synthesis of monohydroxy bile acids have been implicated as pathogenic factors in neonatal cholestasis, there is no direct evidence to show that these bile acids induce cholestasis in the newborn. In the present investigation, we compared the effects of lithocholic acid (LCA) injection on bile flow in suckling (2-week-old) and adult (12-week-old) guinea pigs. Bile flow was not modified by LCA in 2-week-old animals, but it was reduced by 50 to 80% in the adults, the decrease being dose-dependent. In the newborn, the injected LCA was mainly secreted in bile (greater than 90%), while in the adults it was distributed between the liver and bile. The percentage of biliary bile acids (as determined by gas-liquid chromatography) in the two groups was similar before and after LCA injection. Morphologic lesions characteristic of LCA-induced cholestasis were observed only in the adult guinea pigs. This study demonstrates that the newborn guinea pig is less susceptible to cholestasis induced by 90 to 180 mumoles per kg body weight of lithocholate and that, in the neonatal liver, there is no defect in the transport of this bile acid from blood to bile.
A child with cryptogenic cirrhosis underwent a third session of elective sclerotherapy. Endoscopic therapy consisted of intravascular injection of ethanolamine oleate in varices newly developed at the midesophagus level. Irreversible paraplegia was documented within 8 hr postoperatively. Two years later she eventually died from gastrointestinal bleeding. Autopsy findings were compatible with an infarct of the spinal cord secondary to an occlusion of the anterior spinal artery. Various hypotheses which might explain the passage of the sclerosing material from the esophagus to the anterior spinal artery include: arterial occlusion secondary to venous thrombosis and spinal cord necrosis, accidental injection in an intercostal artery or azygous vein through the esophageal wall, the presence of a congenital arteriovenous fistula or the opening of arteriovenous shunt. Paravasal injection of dilute sclerosing agent might protect against this unusual but dramatic complication.
The effect of sulfation of common bile acids on the formation of bile was investigated in male rats by infusing them with the sulfate esters of cholic, chenodeoxycholic, deoxycholic, lithocholic or dehydrocholic acid in four step-wise, increasing doses. Each dose was infused for 30 min and bile collected every 10 min. Control studies were performed by using either albumin solution (the bile acid carrier) or corresponding nonsulfated bile acids at concentrations similar to those of the sulfated products. The secretion of sulfated bile acids was slower and less than that of nonsulfated bile acids, demonstrating transport maximum kinetics rather than the secretory rate maximum characteristic of nonsulfated bile acids. Sulfation significantly increased bile salt-independent bile flow and the choleretic potency of the bile acids tested. With the exception of deoxycholic acid, which had a slight stimulatory effect, bile acid sulfation generally prevented a rise in bile acid-dependent phospholipid and cholesterol secretion. In fact, it reduced biliary phospholipid and cholesterol secretion associated with the secretion of endogenous bile acids. These data are in agreement with the physicochemical properties of sulfated bile acids. They indicate that sulfation prevents the cholestatic action of nonsulfated bile acids, perhaps by increasing bile flow via a high choleretic potential and/or by stimulating bile acid-independent bile flow. The effect of sulfated bile acids on the secretion of biliary phospholipids may protect the canalicular membrane from the detergent properties of bile acids and may thus block the cholestasis which results from high, nonsulfated bile acid concentrations.
Autoimmune enteropathy (AIE) is an entity reported primarily in infancy, resulting in intractable diarrhea and associated with small bowel villous atrophy and the presence of circulating anti-enterocyte (AEA) antibodies. It is a multisystem disorder with a response, in many cases, to immunosuppressive therapy.
The nutritional management of intractable diarrhea and short bowel syndrome remains a challenging problem. The advantage of continuous nasogastric infusion is undisputed, but what to feed remains in question, and no studies, to these authors' knowledge, have yet compared two widely used specially designed protein hydrolysate formulas. A randomized crossover trial of two periods of 7 days was carried out with Alfare and Pregestimil administered by a constant infusion pump in six malnourished infants aged 1-13 months. Two had intractable diarrhea, and four the short bowel syndrome. Identical quantities of calories were administered during the two periods. There was good tolerance for both formulas and satisfactory weight gain. Despite compositional differences related to osmolality, the source of the hydrolysates and their profile, and the qualitative pattern of the carbohydrates, no difference was observed with regard to stool weight, Na+ and K+ losses, and the enteral absorption of fat, carbohydrate-derived energy, and total energy. The percent absorption of nitrogen was somewhat higher (p less than 0.01) with Pregestimil (83.8 +/- 2.7) than with Alfare (77.3 +/- 3.4), but nitrogen retention was unaffected. Energy absorption was the same on both formulas, but maldigested or malabsorbed carbohydrates accounted for 63% of total energy loss during Alfare feeding and 72% during the week of Pregestimil. These data call for studies with protein hydrolysate formulas reformulated with a lower concentration of carbohydrates and a higher one of fat.
Ten pediatric patients, aged 8.5-19 years, with active symptomatic Crohn's disease, received a three-week period of continuous elemental enteral alimentation with no other form of treatment. All patients in this study were selected according to the following criteria, which were applied consecutively: (1) newly diagnosed patients with no previous treatment for Crohn's disease, (2) disease activity index over 200, and (3) no complication requiring surgery. All patients experienced a clinical remission and improved their immunologic and nutritional status during the elemental enteral alimentation. The mean disease activity index for the whole group was 307.0 +/- 23.6 (range: 203 to 413) before and 69.2 +/- 11.4 (range: 15 to 114) after the feeding period. Significant increases in body weight, triceps skinfold, mid-arm circumference, serum transferrin and mean percentage of T lymphocytes were also observed. Following cessation of enteral alimentation, a small declining dose of prednisone was used during a one-year follow-up period. Eight of the ten patients were still in clinical remission three months after the feeding period and their nutritional status had continued to improve during that period of time.
It has been suggested that the quantity of amino acids perfused is a pathogenetic factor in total parenteral nutrition (TPN)-associated hepatotoxicity. However, the effect of the qualitative pattern of amino acid solutions has not been studied. Rats on parenteral nutrition for 5 days received 10.2 g of dextrose and 3.4 g of amino acids daily. Bile flow (microliter/min/g liver protein) after administration of Vamin was 16.2 +/- 0.8, which was similar to that in controls given chow and dextrose iv, but it was significantly higher (p less than 0.001) than those on Travasol (12.3 +/- 0.8). The decrease in bile flow was not related to the large concentrations of alanine and glycine present in Travasol. However, the addition to Travasol of serine present only in Vamin increased bile flow significantly. Bile acid secretion rate, biliary lipid constituents, calcium, sodium, and glucose showed little change. In contrast, alpha-amino nitrogen was increased (p less than 0.05) in Vamin-perfused animals. Steatosis was noted in only a few animals in the Travasol group, and was not associated with an increase in the triglycerides content of the liver. Glycogen and protein content of the livers did not differ. The data show that the composition of amino acid solutions may be a determinant of TPN-induced cholestasis and suggest that the presence of methyl donor amino acids may have a protective effect.
A decrease in the formation/secretion of bile has been well documented in animals on total parenteral nutrition (TPN). Either an excess or an imbalance of amino acids (AA) has been most often implicated. In view of recent work showing that taurine promotes bile flow, bile acid secretion, and protects against hepatotoxic bile acids, the effect of adding taurine (15 mg/dL) to an AA solution was examined in guinea pigs on TPN for 3 days. The TPN-taurine group had a larger bile flow than the group without taurine and had bile acid secretory rates (BASR) similar to those of controls who were on saline by central catheter and had free access to food. Bile composition showed an increase in the secondary bile acid, 7-ketolithocholate and a concomitant decrease in chenodeoxycholate (CDC) in both experimental groups. Taurine led to a reversal of the usual predominance of glycine over taurine conjugated bile acids as well as to increases in HCO3 in cholesterol secretion. In response to a challenge with a large load of CDC, the TPN-taurine animals increased their BASR beyond those observed in the two other groups. These observations suggest that the addition of taurine to TPN solutions could play a role in the prevention of altered biliary function associated with AA solutions.
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