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Biomedical subjects

D G Gall

Publications and source records attributed to D G Gall.

At least 127 records · Page 7Linked to original sources
PubMed1978

A rapid, sensitive method for accurate analysis of individual bile acids in biological fluids by high performance thin-layer chromatography and densitometry.

1. A rapid new micromethod for quantitative analysis of individual bile acids in duodenal juice by high performance thin-layer chromatography (HPTLC) and densitometry is described and evaluated by comparison with standard TLC and spectrophotometry. 2. Advantages of HPTLC over TLC include more rapid separation, better resolution and more sensitive detection (5 - 10 fold), without the need for prior extraction. Densitometry provides simple, direct and rapid quantitation. 3. The method is accurate and reliable over a range of bile acid concentrations. In the 0.5 mM range, recovery was greater than 89%, and coefficients of variation for within-day analysis were 2 - 12% and for between-day analysis were 6 - 18% for the individual bile acids. Twenty analyses can be performed by one worker in a single day. 4. We conclude that the method offers several advantages over most currently described techniques, is suitable for routine use and is deserving of wider application.

Bile Acids and Salts↗
PubMed1978

Reye's syndrome: preservation of mitochondrial enzymes in brain and muscle compared with liver.

The activities of five mitochondrial enzymes tested in liver from patients with Reye's syndrome were measured. Citrate synthase, glutamic dehydrogenase, succinic dehydrogenase, pyruvate carboxylase, and pyruvate dehydrogenase were all outside of the range shown by control samples and well below them in activity. The activity of two extramitochondrial enzymes, glucose-6-phosphatase, which is a microsomal enzyme, and fructose-1,6-diphosphatase, which is a soluble enzyme, were in the normal range in samples from Reye's syndrome patients. In both muscle and brain the activities of the mitochondrial enzyme, citrate synthase, glutamic dehydrogenase, and succinic dehydrogenase were all within the control range. Pyruvate dehydrogenase was found to be normal in muscle from these patients.

Brain↗
PubMed1978

Familial enteropathy: a syndrome of protracted diarrhea from birth, failure to thrive, and hypoplastic villus atrophy.

We have studied 5 infants with persistent severe diarrhea from birth and marked abnormalities of absorption associated with failure to thrive leading to death in 4 infants. Three had siblings who died and a sibling of a 4th is ill at present, all with a similar illness; 2 were the products of consanguinous marriages. Exhaustive investigation failed to identify a recognized disease entity in any patient. Steatorrhea, sugar malabsorption, dehydration, and acidosis were severe in all patients, whatever the diet fed. Total parenteral nutrition was used, but excessive stool water and electrolyte losses persisted even when nothing was fed by mouth. There was no evidence of a hematological or consistent immunological defect in any infant and no abnormalities of intestinal hormones were noted. In the duodenal mucosa of all infants we saw similar abnormalities characterized by villus atrophy, crypt hypoplasia without an increase in mitoses or inflammatory cell infiltrate in the lamina propria and in villus enterocytes absence of a brush border, increase in lysosome-like inclusions, and autophagocytosis. In 3 infants studied by marker perfusion of the proximal jejunum we found abnormal glucose absorption and a blunted response of Na+ absorption to actively transported nonelectrolytes; in 2 there was net secretion of Na+ and H2O in the basal state. Our patients evidently suffered from a congenital enteropathy which caused profound defects in their capacity to assimilate nutrients. The similar structural lesion seen in the small intestinal epithelium of all of our cases undoubtedly contributed to their compromised intestinal function, but the pathogenesis of this disorder, if indeed it is a single disease, remains obscure.

Acidosis↗
PubMed1977

Human rotavirus enteritis induced in conventional piglets. Intestinal structure and transport.

To better understand the pathogenesis of infantile viral gastroenteritis, we studied Na+ and Cl- fluxes in vitro in short-circuited jejunal epithelium from 8-10-day-old piglets after infection with a standard dose of human rotavirus given via nasogastric tube. 11 infected piglets, all of whom became ill, were compared with 9 uninfected, healthy litter-mates. When killed 72 h after infection, intestinal villi were shorter and crypts deeper (P less than 0.025) in duodenum, upper jejunum, and mid-small intestine, but not ileum in infected piglets. Virus antigen was seen by fluorescence microscopy in occasional jejunal villus tip cells in only four infected piglets and no controls at 72 h. Net Na+ and Cl- fluxes did not differ from noninfected litter-mate controls under basal conditions, but response to glucose was blunted in infected piglets (P less than 0.001). Theophylline stimulated net Cl- secretion in both infected and control animals, and cyclic AMP concentration in isolated jejunal villus enterocytes did not differ significantly. In isolated jejunal villus enterocytes of infected piglets, thymidine kinase activity increased (P less than 0.001), and sucrase activity decreased (P less than 0.001). We conclude that in this invasive enteritis caused by a major human viral pathogen, glucose-coupled Na+ transport is impaired in the jejunum at a time when the villus epithelium shows enzyme characteristics of crypt epithelium, and when little or no virus is present. These findings are identical to those occurring in an invasive coronavirus enteritis of piglets but differ markedly from those seen with enterotoxigenic diarrhea.

Animals↗
PubMed1977

Deficient activity of hepatic pyruvate dehydrogenase and pyruvate carboxylase in Reye's syndrome.

The activity of certain hepatic enzymes involved in carbohydrate metabolism was measured in postmortem samples from six cases of Reye's syndrome. The activities of the two exclusively extramitochondrial enzymes, glucose-6-phosphatase and fructose-1,6-diphosphatase, were all within the normal range. Activities of pyruvate carboxylase and pyruvate dehydrogenase, both of which are exclusively mitochondrial enzymes, were below levels, shown by control tissue in every case, the average being 21.7% of the lowest control value for pyruvate carboxylase and 11.6% of that for pyruvate dehydrogenase. Impaired pyruvate metabolism appears to be another feature in Reye's syndrome.

Adolescent↗
PubMed1977

Catecholamine and octopamine concentrations in brains of patients with Reye syndrome.

Dopamine, norepinephrine, and octopamine levels were estimated in regions of brains obtained postmortem from children who died with Reye syndrome and from age-matched controls. Hypothalamic norepinephrine levels were greatly decreased (to 30 percent of control, p less than 0.02) and octopamine levels were increased (to 700 percent of control, p less than 0.01). Levodopa had little effect on the physiologic condition of the patients. However, CNS dopamine and homovanillic concentrations were not elevated by levodopa, indicating that in the present cases levodopa was not metabolized to its catecholamine products. The findings indicate that the encephalopathy of Reye syndrome (as in other types of hepatic coma) may be linked to the presence of false transmitters in the brain and that levodopa is a rational therapy if administered before irreversible CNS changes occur.

Brain Chemistry↗
PubMed1977

Na+ transport in jejunal crypt cells.

As enterocytes migrate from crypts to villi they differentiate and mature. To examine the effect of epithelial differentiation on ion transport we studied 22Na+ efflux and (Na+--K+)-adenosine triphosphatase activity in suspensions of epithelial cells selectively isolated from different regions of the villus to compare crypt cells with villous tip cells. Enterocytes were isolated from rat jejunum by a dilation-vibration technique. Thymidine kinase, sucrase, and alkaline phosphatase activities were measured as markers of specific cell populations. Compared to villous cells, cells from the crypt region demonstrated lower (Na"--K+)-adenosine triphosphatase activity, lower total and passive Na+ efflux rate constants, and failure of Na+ transport to respond to an actively transported nonelectrolyte.

Adenosine Triphosphatases↗
PubMed1977

Acrodermatitis enteropathica, zinc, and the Paneth cell. A case report with family studies.

An infant with acrodermatitis enteropathica was studied before and after starting zinc therapy. Clinical recovery was rapid, and the plasma zinc, serum and mucosal alkaline phosphatase activities returned to normal. Light microscopy of small intestinal biopsies showed normal mucosa. Electron microscopy of the Paneth cells initially revealed abnormal inclusion bodies which disappeared during therapy, suggesting that the abnormality is secondary to zinc deficiency, and not a primary defect. These abnormal inclusions may represent altered secretory granules and a proliferation of lysosomes. We were unable to define the heterozygous state biochemically or histologically.

Acrodermatitis↗
PubMed1977

Transmissible gastroenteritis: sodium transport and the intestinal epithelium during the course of viral enteritis.

Sodium transport, mucosal structure, and epithelial enzymes were studied in piglets killed 10, 25, 40, 72, or 144 hr after infection with a standard dose of transmissible gastroenteritis virus. Glucose-stimulated Na transport measured in short-circuited jejunal epithelium and suspensions of villous enterocytes became progressively more abnormal during the first 40 hr, but recovered completely by 144 hr. As Na transport deteriorated, jejunal mucosal villi shortened and crypts deepened; cells isolated from the villi became more crypt-like in their enzyme profile, with high levels of thymidine kinase and low levels of sucrase activity 40 hr after infection. At 40 hr, when diarrhea is severe, little if any virus has been found in the epithelium. Our data suggest that the relatively undifferentiated crypt type enterocytes on the villi constitute an important determinant of altered Na transport and diarrhea in this invasive viral enteritis.

Animals↗
PubMed1976

Sodium ion transport in isolated intestinal epithelial cells. II. Comparison of the effect of actively transported sugars on sodium ion efflux in cells isolated from jejunum and ileum.

Na+ transport studies in intestinal epithelial cells indicate that enterocytes from different regions of the small intestine differ in their response to actively transported sugars. 1. Compared with sugar-free medium total Na+ efflux rate constants from isolated rat jejunal cells were significantly increased when medium contained actively transported sugars, glucose and galactose, but not when medium contained fructose. 2 In contrast total Na+ efflux rate constants from isolated rat ileal cells did not respond to actively transported sugars, glucose and galactose. 3. Similar results for the effect of actively transported sugars on Na+ ellux were obtained for isolated rabbit jejunal and ileal epithelial cells. 4. Passive Na+ efflux rate constants for isolated jejunal and ileal enterocytes are not significantly different, indicating similiar permeability characteristics.

Animals↗
PubMed1976

Viral gastroenteritis: recent progress, remaining problems.

Infants and young children are particularly susceptible to a recently identified viral enteritis which is highly contagious and seems both common and universal. In this disease, virus invades the upper intestinal epithelium, causing acute diarrhoea with early fever and vomiting. We studied a similar disease in pigs, infecting three-week-old animals with transmissible gastroenteritis virus (TGE), which also invades the upper intestinal epithelium. In this model, diarrhoea is massive 16-40 hours after infection, when stools contain increased electrolytes but no excess of sugar. In the jejunum of intact pigs at the 40-hour stage we found altered Na+ and water flux, decreased mucosal activities of disaccharidases and Na+, K+-ATPase, but normal adenylate cyclase activity. At the same stage the response of Na+ flux to glucose was blunted in jejunal epithelium studied in Ussing short-circuit chambers and in suspensions of villous cells; Cl- flux responded normally to theophylline, and thymidine kinase and sucrase activities of cells isolated from jejunal villi were similar to those found in crypt cells. Probably by 40 hours after infection most virus has been shed from the mucosa. Viral diarrhoea clearly differs from enterotoxigenic diarrhoea. Consideration of its pathogenesis must take into account the dynamic nature of the mucosal epithelium and the factors governing differentiation of enterocytes as they migrate from crypt to villus. Sufficient information is available now to characterize one specific and apparently prevalent viral enteritis in man and to identify additional viral enteritides. There is hope that preventative therapy can be developed. Our understanding of the mechanisms of viral diarrhoea is limited, but the availability of an animal model and the promise of others makes us optimistic that these deficiencies can be remedied. Greater understanding of the pathogenesis of viral diarrhoea should better the active therapy of affected infants and children.

Animals↗
PubMed1976

Transmissible gastroenteritis. Mucosal ion transport in acute viral enteritis.

Ion transport in the jejunal mucosa of 14-to 16-day-old piglets with severe diarrhea 40 hr after infection with transmissible gastroenteritis (TGE) virus was studied. In infected pigs Na+ transport failed to respond normally to glucose when studied either in Ussing short-circuited chambers or in suspensions of enterocytes isolated selectively from jejunal villi. Theophylline, 10mM, added to the chambers produced the same brisk electrical responses and increments in net Cl- secretion in tissue from both infected and control groups. A defect in glucose-stimulated Na+ absorption in the acute stage of a viral enteritis has been identified which probably contributes to the impaired lumen-to-extracellular fluid flux of Na+ found previously in the jejunum of intact TGE-infected pigs. The mechanisms causing diarrhea in this invasive viral enteritis differ from those causing toxigenic diarrhea.

Acute Disease↗
PubMed1975

Acute liver disease and encephalopathy mimicking Reye syndrome. A report of three cases.

Three patients are described whose clinical presentation suggested Reye syndrome, and in whom the initial laboratory investigations supported the diagnosis. The subsequent clinical and biochemical evolution of the illness differed from that of Reye syndrome. The liver biopsy of each patient revealed changes in centrilobular hepatocytes rather than the diffuse small droplet fatty change characteristic of Reye syndrome. In each of them normal liver functions were regained. The findings in these patients suggest that a firm diagnosis of Reye syndrome cannot be made without histologic examination of the liver.

Acute Disease↗