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Biomedical subjects

J G Banwell

Publications and source records attributed to J G Banwell.

18 recordsLinked to original sources
PubMed1992

Pyostomatitis vegetans and primary sclerosing cholangitis: markers of inflammatory bowel disease.

The case of a 34-year-old woman with both pyostomatitis vegetans and primary sclerosing cholangitis is reported and the literature reviewed. Pyostomatitis vegetans is a rare disorder characterized by friable pustules on the buccal mucosa and often peripheral blood eosinophilia. In this review, the frequent association of pyostomatitis vegetans with inflammatory bowel disease as well as the potential for pyostomatitis vegetans to present with sclerosing cholangitis and liver disease before any other manifestations of inflammatory bowel disease is discussed. Patients with pyostomatitis vegetans may need long-term care for gastroenterological disease in addition to treatment for oral lesions.

Adult↗
PubMed1990

Worldwide impact of oral rehydration therapy.

Oral rehydration therapy (ORT) has had a dramatic global impact. The worldwide consequences of this therapy are discussed in four categories: (1) adoption of ORT as the primary therapy for acute dehydrating diarrhea; (2) establishment of national ORT programs; (3) scientific knowledge gained from studies into intestinal absorption of oral rehydration solutions; and (4) implications of ORT for the next decade. The Diarrheal Disease Control Program has been assigned a high priority by the World Health Organization. It now includes 99% of the population of the developing world, although it is not uniformly implemented. Because knowledge of how to use ORT parallels implementation, it is hoped that expanded training of community health workers will increase implementation. In addition, specific indications for ORT need further study and refinement so that community health workers may learn to distinguish between diarrheal episodes that require such therapy and those that do not. Better scientific understanding of intestinal absorption of ORT fluids has led to the development of new formulations that enhance absorption of nutrients and repletion of electrolytes. The optimal composition of such revised solutions has yet to be established. In addition to these improvements in utilization, distribution, education, and application of ORT, other measures to reduce the morbidity and mortality from diarrhea can be expected in the areas of better infant feeding practices, improved sanitation, management of persistent diarrhea, targeted therapy for particular groups of infants at high risk, and immunization.

Diarrhea↗
PubMed1989

Intestinal sphingolipid excretion associated with feeding of phytohemagglutinin lectin (Phaseolus vulgaris) to germ-free and conventional rats.

Intestinal sphingolipids of feces of germ-free and conventional rats were analyzed during the pair feeding of a complete defined diet containing phytohemagglutinin lectin (PHA) from red kidney beans (Phaseolus vulgaris) as 1% dietary protein in comparison to casein fed controls. Phytohemagglutinin in the diet increased the total fecal excretion of sphingomyelins (18-fold for germ-free and 20-fold for conventional rats), of non-acid glycosphingolipids (3.5-fold for germ-free and 9-fold for conventional rats) and also of the gangliosides (2.5-fold) for the germ-free rats compared to controls. For germ-free rats the increase of non-acid glycolipids was ascribed to an effect of the lectin strictly on the small intestinal mucosa, while for conventional rats an effect was seen also on the large intestinal mucosa. Increase of fecal gangliosides of germ-free rats was due mainly to an increased excretion of N-acetylneuraminosyl-lactosylceramide, a ganglioside species restricted to epithelial cells of duodenum, of upper jejunum and of large intestines. The effects on glycolipid excretion observed in germ-free rats and the rather similar effects seen in conventional animals suggested that the influence of dietary PHA was due directly to effects elicited by PHA binding to the enterocyte brush border membrane and not to secondary effects induced by increase in the luminal microflora.

Animals↗
PubMed1988

Bacteria-lectin interactions in phytohemagglutinin-induced bacterial overgrowth of the small intestine.

The mechanism of phytohemagglutinin-induced bacterial overgrowth of the small bowel in the rat was studied. Interaction of the lectin with bacterial isolates selected at random from those that comprised the major population of the overgrowth was determined. In both bacterial agglutination assays and glycocalyx stabilization, no specific association between lectin and bacteria was seen. In three independent binding assays phytohemagglutinin was not found to increase bacterial adherence to washed intestinal mucosa. Phytohemagglutinin would not appear to act, therefore, as a direct ligand to mediate bacterial adherence or to modify the mucosal surface to increase bacterial adherence.

Agglutination Tests↗
PubMed1988

Bacterial overgrowth by indigenous microflora in the phytohemagglutinin-fed rat.

Phytohemagglutinin lectin (PHA) derived from red kidney bean (Phaseolus vulgaris) causes bacterial and protozoal colonization of the rat small intestine. To provide additional insights into this phenomenon we have studied the time course and population dynamics of microbial colonization of the major aerobe--facultative anaerobe groups which characterize this microflora. Compared with controls, PHA caused proliferation of a consistent adherent microbial flora in the jejunum (P less than 0.01). The predominant bacteria identified were Escherichia coli. a Streptococcal sp., and Lactobacillus. Escherichia coli isolates expressed no predominant serotype or fimbriae; none elaborated heat-labile or heat-stable toxin. Both E. coli and Streptococcal sp. populations increased within 24 h of PHA feeding and were sustained during further exposure to PHA (P less than 0.05). On reversion to a control diet, coliform counts fell progressively within 24-48 h and continued to decline, whereas gram-positive rod and coccus flora became the more prominent colonizers through days 1 to 4 of the reversion.

Animals↗
PubMed1986

Phytohemagglutinin from red kidney bean (Phaseolus vulgaris) inhibits sodium and chloride absorption in the rabbit ileum.

Phytohemagglutinin (PHA), derived from red kidney bean (Phaseolus vulgaris), can induce malabsorption and diarrhea when fed to rats. In this study, we determined the effect of PHA on ion transport in the rabbit ileum in vitro. Compared with control tissues, PHA (1 mg/ml) added to the mucosal solution increased short-circuit current (1.1 +/- 0.2 microEq/cm2 X h, p less than 0.001), decreased net Na (-1.0 +/- 0.5 microEq/cm2 X h, p less than 0.02) and Cl (-1.2 +/- 0.6 microEq/cm2 X h, p less than 0.025) absorption, and decreased tissue conductance (-1.8 +/- 0.5 mS/cm2, p less than 0.001). Serosal addition of PHA had no effect on the short-circuit current or tissue conductance. Mucosal PHA did not increase mucosal levels of cyclic adenosine monophosphate or cyclic guanosine monophosphate. Removal of serosal calcium did not affect the increase in short-circuit current induced by mucosal PHA. Utilizing fluorescent microscopy, rhodamine-labeled PHA was found to bind to the luminal border of villus cells, but not to crypt cells, in the ileum. In the descending rabbit colon, PHA did not affect either the short-circuit current or conductance, and rhodaminated PHA did not bind to the epithelial surface. Using the increase in short-circuit current as an indicator of absorption, PHA did not affect Na-coupled glucose or amino acid absorption in the ileum. This study suggests that dietary lectins may play a role in regulating intestinal fluid and electrolyte transport.

Animals↗
PubMed1985

Effects of vegetable diets on nitrogen metabolism in cirrhotic subjects.

This study compared the effect of a vegetable diet with an animal protein diet on various aspects of nitrogen metabolism to identify what components of the vegetable diet might be causing beneficial therapeutic effects in hepatic encephalopathy. Vegetable diets contained 4.5-fold greater amounts of fiber (56 +/- 3 g/day) and reduced amounts of methionine, tyrosine, and tryptophan. In 6 stable cirrhotic subjects without encephalopathy, vegetable diets caused a significant reduction in the urea production rate from 106 +/- 5 to 89 +/- 5 mg X kg-1 X 24 h-1 of urea nitrogen. This was mainly accounted for by a fall in urinary urea output. Vegetable diets also caused a fall in total urinary nitrogen, which was accounted for by the fall in urea nitrogen, and a comparable increase in fecal nitrogen from 12 +/- 2 to 28 +/- 5 mg X kg-1 X 24 h-1. The fecal bacterial fraction contained 63% of the increase in stool nitrogen. Most plasma amino acids, including methionine, tyrosine, phenylalanine, as well as total and free tryptophan, were unchanged. The effect of vegetable diets on nitrogen metabolism can be mainly accounted for by the increased intake of dietary fiber and increased incorporation and elimination of nitrogen in fecal bacteria.

Aged↗
PubMed1979

Environmental contaminants and intestinal function.

THE ENVIRONMENTAL CONTAMINANTS WHICH HAVE THEIR MAJOR EFFECTS ON THE SMALL INTESTINE MAY BE CLASSIFIED INTO FIVE MAJOR CATEGORIES: (1) bacterial, viral, and parasitic agents, (2) food and plant substances, (3) environmental and industrial products, (4) pharmaceutical agents, and (5) toxic agents whose metabolic effects are dependent on interreaction with intestinal bacterial flora, other physical agents (detergents), human intestinal enzyme deficiency states, and the nutritional state of the host.Bacterial, viral, and parasitic agents are the most important of all such agents, being responsible for significant mortality and morbidity in association with diarrheal diseases of adults and children. Several plant substances ingested as foods have unique effects on the small bowel as well as from contaminants such as fungi on poorly preserved grains and cereals. Environmental and industrial products, in spite of their widespread prevalence in industrial societies as contaminants, are less important unless unexpectedly intense exposure occurs to the intestinal tract. Pharmaceutical agents of several types interreact with the small bowel mucosa causing impairment of transport processes for fluid and electrolytes, amino acid, lipid and sugars as well as vitamins. These interreactions may be dependent on bacterial metabolic activity, association with detergents, mucosal enzyme deficiency state (disaccharidases), and the state of nutrition of the subject.

Bacteria↗
PubMed1978

Purification of tritium-labeled cholera toxin.

Cholera toxin was labeled with tritium by the Wilzbach technique, and highly purified radiolabeled toxin was obtained by Sephadex column chromatography and disc gel electrophoresis. 3H-labeled cholera toxin retained its biological activity and chemical stability and had a specific activity of 405.9 muCi/mumol. The methods utilized in extraction and purification of 3H-labeled toxin may be advantageous for preparation of other biologically active radiolabeled proteins.

Cholera Toxin↗
PubMed1978

Hookworm.

Explore the source record for details and available documents.

Ancylostomatoidea↗
PubMed1978

Identification of the dietary lectin, wheat germ agglutinin, in human intestinal contents.

Plant lectins are known to have potent biological actions of normal and malignant cells. High concentrations of these lectins are present in many types of high residue diets. The specific binding of wheat germ agglutinin, a dietary plant lectin, to N-acetylglucosamine was used as the basis for purification of this lectin by biospecific chitin affinity chromatography. Subsequently, methods were developed for the extraction, purification, and identification of wheat germ agglutinin from fecal samples. Biologically intact wheat germ agglutinin was detected in ileostomy effluent and fecal collections from human subjects consuming a diet containing wheat germ. These studies demonstrate that wheat germ agglutinin can traverse the human small intestine intact. It is feasible that orally ingested wheat germ agglutinin and other plant lectins which interact with a wide variety of cell membranes may alter intestinal epithelial or bacterial cell function in the human bowel.

Feces↗
PubMed1978

Small intestinal epithelial renewal in the Syrian hamster exposed to cholera enterotoxin.

Epithelial renewal of the small intestine was measured in the Syrian hamster utilizing tritiated thymidine by standard autoradiographic and a scintillation counting technique. Scintillation counting of intestinal replicates proved to be as accurate as standard autoradiography. Average mucosal cell turnover was 71 +/- 3.0 hr in jejunum and 79 +/- 4.2 hr in ileum. Scintillation counting was utilized to study the effect of a maximum cholera enterotoxic secretory stimulus on small intestinal mucosal cell turnover. No significant change in epithelial cell migration occurred during cholera enterotoxin (CT)-induced fluid and electrolyte secretion. The rate of decline in radioactivity as a measure of cell turnover in CT-exposed animals was no different from controls. Epithelial cell proliferation 1 to 42 hr after CT exposure showed no difference from controls. Intestinal fluid and electrolyte secretion persisted for 24 hr after CT exposure. It is concluded that (1) the small intestinal epithelial cell migration was unaltered by this metabolic secretory stimulus, and (2) the data are consistent with the concept that epithelial migration after CT exposure was one factor, although not necessarily the major determinant of the progressive decline in intestinal secretory activity.

Animals↗
PubMed1976

The Syrian hamster: a reproducible model for studying changes in intestinal fluid secretion in response to enterotoxin challenge.

Syrian hamsters respond in a predictable and reproducible manner to intragastric administration of purified cholera enterotoxin by intraluminal accumulation of fluid in the small bowel, cecum, and proximal colon. In the majority of animals this process is self limiting, and recovery occurs with full reabsorption of intestinal fluid by 30 to 35 h. The secretory response to 75 mug of cholera toxin has been defined, and the model was utilized to study the inhibitory effects of indomethacin, polymyxin B sulfate, glucose electrolyte solutions, and colchicine. These studies demonstrate its potential usefulness as a convenient and inexpensive technique for evaluation of pharmacological agents that might inhibit intestinal fluid secretion.

Animals↗
PubMed1975

Comparison of secretory and histological effects of shigella and cholera enterotoxins in rabbit jejunum.

The purpose of this study was to compare the actions of shigella toxin and cholera toxin to determine if mucosal damage is a prerequisite for shigella toxin-induced secretion. The secretory response to maximal doses of cholera toxin and shigella toxin were compared. The maximal rate of secretion and the electrolyte and protein concentration of the intestinal fluid were similar for both toxins. On the other hand, the time of onset after exposure to the toxin was 105 min for shigella toxin and 15 to 30 min for cholera toxin. In addition, cholera toxin-induced secretion was associated with depletion of goblet cell mucus, whereas no change was seen in association with the response to shigella toxin. Other than goblet cell depletion, there were no histological differences between loops secreting in response to cholera toxin and to shigella toxin. Finally, the secretory effect of the toxins are not additive. These studies suggest that, in spite of apparent differences in the patterns of secretory response to the two toxins, they may share a rate-limiting step in the secretory process.

Animals↗
PubMedDate not supplied

Pathophysiology of diarrheal disorders.

Travelers' diarrhea is only mild or moderate in the majority of cases. Consequently, severe fluid and electrolyte losses are encountered only rarely. Secretory, osmotic, and inflammatory processes in the intestine result in increased losses of fluid and electrolytes due to diarrhea. Disorders of intestinal motor activity, coupled with fluid secretion, may also have a role in causing an increase in the frequency of bowel movements. Several systemic symptoms, such as malaise, fatigue, anorexia, nausea, and fever, are commonly associated with diarrhea and contribute to significant morbidity, which is often sufficient to compromise effective participation in a vacation or business trip. Several putative mechanisms for the systemic symptoms associated with travelers' diarrhea are discussed in light of recent understanding of the enteric nervous system, intestinal neuropeptides and hormones, and other inflammatory mediators released from the bowel wall during enteric infections.

Biological Transport, Active↗