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At least 1,693 records · Page 94Linked to original sources
PubMed1985

Watery diarrhea-hypokalemia-achlorhydria syndrome and carcinoma of the esophagus.

The watery diarrhea-hypokalemia-achlorhydria syndrome associated with ectopic secretion of vasoactive intestinal peptide has only been conclusively documented with tumors originating in the pancreas or sympathetic chain. We report here the case of a 50-yr-old woman who developed this syndrome 3 wk after an apparently effective course of radiotherapy for an obstructing, mixed-cell carcinoma of the esophagus. High concentrations of vasoactive intestinal peptide were found in plasma (100-200 pmol/L; normal less than 20 pmol/L) and in the metastatic skin nodules (750 pmol/g) that later developed and that contained one of the two cell types from the original tumor. Stool volumes reached a plateau of 15-20 L/day, and potassium requirements were greater than 1000 mmol/day. Symptoms failed to respond to any of the regimens previously described as effective in this syndrome. After 14 wk of massive fecal fluid and electrolyte losses, symptoms resolved dramatically with the first dose of 5-fluorouracil. Plasma vasoactive intestinal peptide concentration returned to normal, where it remained despite subsequent evidence of renewed tumor spread. This case illustrates the unpredictability of the response of this syndrome to medical treatment, and suggests that vasoactive intestinal peptide secretion may occur in a wider range of tumors than has so far been described.

Achlorhydria↗
PubMed1997

Small intestinal bacterial overgrowth in the symptomatic elderly.

OBJECTIVE: 1) To determine the prevalence of small intestinal overgrowth with colonic-type bacteria in symptomatic elderly subjects, particularly those without important "clues" such as clinically apparent predisposition or vitamin B12 deficiency, and 2) to investigate defense mechanisms such as gastric acidity, small intestinal motility, and luminal IgA in this setting. METHODS: Fifty-two symptomatic subjects without vitamin B12 deficiency or clinically apparent predisposition to bacterial overgrowth or disturbed mucosal immunity, including 22 subjects > or = 75 yr old, underwent culture of small intestinal luminal secretions. Indicator paper was used to measure fasting gastric pH. The presence of bacteria of confirmed nonsalivary origin in small intestinal secretions served as an index of small intestinal dysmotility. Small intestinal luminal IgA concentrations were measured by radial immunodiffusion. RESULTS: Small intestinal overgrowth with colonic-type flora was not present in any subject investigated for dyspepsia, irrespective of age. In subjects with chronic diarrhea, anorexia, or nausea, overgrowth with colonic-type flora (Enterobacteriaceae) was present in 0/12 (0%), 1/10 (10.0%), and 9/14 (64.3%) subjects aged < 50 yr, 50-74 yr, and > or = 75 yr, respectively. Enterobacteriaceae were not concurrently recovered from saliva of any subject > or = 75 yr old with small intestinal overgrowth with these bacteria. Fasting hypochlorhydria was present in only 1/9 (11.1%) such subjects. Luminal IgA concentrations were significantly greater in subjects > or = 75 yr old with bacterial overgrowth than in culture-negative subjects (p < or = 0.003). CONCLUSIONS: Small intestinal overgrowth with colonic-type bacterial should be considered in subjects > or = 75 yr old with chronic diarrhea, anorexia, or nausea, even in the absence of clues such as clinically apparent predisposition or vitamin B12 deficiency. Small intestinal dysmotility, rather than fasting hypochlorhydria or mucosal immunosenescence, probably is responsible for the prevalence of bacterial overgrowth in this group.

Aged↗
PubMed1989

Evidence that vasoactive intestinal peptide induces ductular secretion of bile in humans.

The effect of intravenously administered vasoactive intestinal polypeptide on bile secretion was studied in 11 patients with complete biliary drainage. After infusion of vasoactive intestinal polypeptide, bile volume increased by 65%. In the 2 patients investigated, the output of bicarbonate increased by approximately 250% and the concentration by 50%-70%. Vasoactive intestinal polypeptide thus caused a bicarbonate-rich choleresis. The output of biliary lipids was not affected by infusion of vasoactive intestinal polypeptide, whereas the concentration decreased by approximately 40%. The canalicular bile flow, measured by the clearance of [14C]erythritol, was not affected by infusion of vasoactive intestinal polypeptide. The choleretic effect of vasoactive intestinal polypeptide thus seems to occur only at the ductular level. The ductular bile flow was calculated to be stimulated threefold to fourfold.

Bicarbonates↗
PubMed1990

Vasoactive intestinal peptide (VIP) and peptide histidine methionine (PHM) in human eccrine sweat glands: demonstration of innervation, specific binding sites and presence in secretions.

Vasoactive intestinal peptide (VIP) and peptide histidine methionine (PHM) immunoreactivities have been detected in alcohol extracts of human axillary skin using sensitive and specific radioimmunoassays. VIP immunoreactivity (7.63 + 2.33 pmol/g, x + SE, n = 9) was more abundant than PHM immunoreactivity (3.86 + 0.56 pmol/g, x + SE, n = 9). Immunocytochemistry of sections of skin revealed a network of VIP/PHM immunoreactive nerve fibres around the perimeter of eccrine but not apocrine sweat glands. In vitro autoradiography of skin sections using 125I-labelled VIP and PHM, demonstrated binding sites on the membranes of eccrine gland secretory cells. The binding of each radiolabelled ligand was eliminated by the presence of a large molar excess of appropriate cold peptide but was unaffected when incubated with related peptide, indicating the presence of specific binding sites for both VIP and PHM. Radioimmunoassay of Sep-pak concentrated human sweat identified the presence of both VIP immunoreactivity (30.6 pmol/l) and PHM immunoreactivity (43.4 pmol/l). Reverse-phase HPLC analysis of axillary skin extracts and sweat, followed by radioimmunoassay of fractions, identified single resolved peaks of VIP and PHM immunoreactivity with identical retention times to synthetic standards. Eccrine sweat glands in human axillary skin have VIP and PHM peptidergic innervation and possess specific binding sites for each peptide which are both secreted to the surface of the skin.

Binding Sites↗
PubMed2005

Lack of guanylyl cyclase C, the receptor for Escherichia coli heat-stable enterotoxin, results in reduced polyp formation and increased apoptosis in the multiple intestinal neoplasia (Min) mouse model.

Guanylyl cyclase C (GC-C), a transmembrane receptor for bacterial heat-stable enterotoxin and the mammalian peptides guanylin and uroguanylin, mediates intestinal ion secretion and affects intestinal cell growth via cyclic GMP signaling. In intestinal tumors, GC-C expression is maintained while guanylin and uroguanylin expression is lost, suggesting a role for GC-C activation in tumor formation or growth. We show by in situ hybridization that GC-C expression is retained in adenomas from multiple intestinal neoplasia (Apc(Min/+)) mice. In order to determine the in vivo role of GC-C in intestinal tumorigenesis, we generated Apc(Min/+) mice homozygous for a targeted deletion of the gene encoding GC-C and hypothesized that these mice would have increased tumor multiplicity and size compared to wild-type Apc(Min/+) mice on the same genetic background. In contrast, the absence of GC-C resulted in a reduction of median polyp number by 55%. There was no change in the median diameter of polyps, suggesting no effect on tumor growth. Somatic loss of the wild-type Apc allele, an initiating event in intestinal tumorigenesis, also occurred in polyps from GC-C-deficient Apc(Min/+) mice. We have found increased levels of apoptosis as well as increased caspase-3 and caspase-7 gene expression in the intestines of GC-C-deficient Apc(Min/+) mice compared with Apc(Min/+) mice. We propose that these alterations are a possible compensatory mechanism by which loss of GC-C signaling also affects tumorigenesis.

Animals↗
PubMed1992

Regulation of secretion by vasoactive intestinal peptide in isolated perfused rat submandibular glands.

The isolated, perfused gland was used to examine the regulation of saliva volume and protein content by vasoactive intestinal peptide (VIP). In the absence of other secretagogues, VIP produced a modest, sustained saliva flow with a biphasic dose-response curve in which saliva volume was greatest at 1 nM VIP (28.5 +/- 3.8 microliters in the first 5 min, n = 4) but reduced at lower and higher concentrations. The protein concentration in saliva released in response to VIP (0.86 +/- 0.13 micrograms/microliters) was substantially higher than with 30 nM acetylcholine (0.06 +/- 0.02 micrograms/microliters) or 1 nM substance P (0.30 +/- 0.05 micrograms/microliters). During the first 5 min of stimulation, VIP and substance P were synergistic in terms of volume and protein content whereas inclusion of VIP did not increase acetylcholine-stimulated flow in the first 5 min but produced a higher sustained flow over the next hour. After stimulation with acetylcholine, subsequent addition of VIP transiently enhanced saliva volume and protein content in a monophasic, dose-dependent manner with effects at 1 pM VIP and higher. The responses were different for VIP compared with other cAMP-mobilizing agents and the involvement of multiple VIP receptor subtypes was suggested from experiments in which a VIP antagonist blocked the VIP enhancement of saliva volume but not the increase in protein.

Acetylcholine↗
PubMed1984

Cleavage of two yolk proteins from a precursor in Caenorhabditis elegans.

Four yolk proteins have been identified previously in the nematode Caenorhabditis elegans. However, only two of these proteins ( yp170A and yp170B ) are found among the products of in vitro translation of nematode RNA. The other two yolk proteins ( yp115 and yp88 ) are apparently cleaved from a precursor polypeptide of approximately 180,000 Mr. This precursor has been identified as an in vitro translation product and as a metabolically unstable polypeptide in vivo. It is bound by immunoglobulin G (IgG) specific for yp115 and by IgG specific for yp88 . The immunoadsorbed material yields the same pattern of fragments on partial digestion with Staphylococcus aureus V8 protease regardless of whether anti- yp115 or anti- yp88 IgG is used in the adsorption. Like the yp170 polypeptides, the yp115 / yp88 precursor is synthesized by the intestine and secreted intact. The precursor is evidently cleaved to yield yp115 and yp88 after secretion from the intestine but independent of the presence of the gonad. Thus, cleavage probably occurs in the body cavity of the nematode.

Animals↗
PubMed1996

Secretion of human intestinal angiotensin-converting enzyme and its association with the differentiation state of intestinal cells.

Human angiotensin I-converting enzyme (ACE) exists in intestinal epithelial cells as a membrane-bound (ACEm) and secretory glycoprotein (ACEsec). The electrophoretic mobilities of ACEsec and ACEm on SDS/polyacrylamide gels are similar; the N-deglycosylated ACEsec and ACEm, in contrast, display slight differences in their apparent molecular masses, indicating that the carbohydrate contents of ACEsec and ACEm are different. Moreover, ACEsec is solely N-glycosylated whereas ACEm is N- and O-glycosylated, assessed by lectin binding studies. Spontaneous release of ACEsec is achieved by incubation of brush border membranes at 37 degrees C. Aprotinin, leupeptin and EDTA partly inhibit the generation of ACEsec, strongly suggesting that ACEsec is generated from ACEm by proteolytic cleavage. The expression levels of ACEsec in the intestine may be associated with the differentiation state of mucosal cells. Thus ACEsec is more abundant than ACEm in immature non-epithelial crypt cells of patients with coeliac disease. Well-differentiated epithelial cells, by contrast, contain predominantly ACEm. The variations in the proportions of cleaved ACEsec in differentiated and non-differentiated cells may be due to varying levels of the cleaving protease. Alternatively, because epithelial cell differentiation is accompanied by alterations in the levels of oligosaccharyltransferases, the results suggest a critical role for the glycosylation pattern of ACEm in its susceptibility to the putative cleaving protease.

Aprotinin↗
PubMed1985

Investigation of drug absorption from the gastrointestinal tract of man. IV. Influence of food and digestive secretions on metoprolol jejunal absorption.

The influence of nutrients and digestive secretions on the intestinal absorption and bioavailability of the beta-adrenoceptor antagonist, metoprolol, was investigated in an isolated segment of jejunum using an intestinal perfusion technique. Two solutions containing metoprolol, one with, and one without nutrients, were perfused into the jejunum with an occluding balloon inflated or deflated. Jejunal fluid, blood and urine samples were then collected for drug or metabolite estimation. In the segment studied, metoprolol absorption from the nutrient solution was four times that observed during perfusion of the saline solution. Bile salts did not enhance drug absorption. Both in the presence and absence of nutrients, a linear relationship was observed between the computed cumulative amount of drug absorbed from the gastrointestinal tract and the resulting plasma concentration at each sampling time, indicating that first-pass loss was not saturated. This result was also reflected in the similarity of the AUC:dose ratios, and in the lack of effect of nutrients on the metabolism of the drug.

Adult↗
PubMed2003

Effects of nonpathogenic bacteria on cytokine secretion by human intestinal mucosa.

OBJECTIVE: The human intestine harbors a complex microbial ecosystem, and the mucosa is the interface between the immune system and the luminal environment. The aim of this study was to elucidate whether host-bacteria interactions influence mucosal cytokine production. METHODS: Macroscopically normal colonic specimens were obtained at surgery from eight patients with neoplasm, and inflamed ileal specimens were obtained from two patients with Crohn's disease. Mucosal explants were cultured for 24 h with either nonpathogenic Escherichia coli ECOR-26, Lactobacillus casei DN-114 001, L. casei DN-114 056, L. casei ATCC-334, or Lactobacillus bulgaricus LB-10. Each study included blank wells with no bacteria. Tissue and bacteria viability were confirmed by LDH release and culture. Concentration of tumor necrosis factor (TNF)alpha, transforming growth factor beta1, interleukin (IL)-8, and IL-10 was measured in supernatants. In parallel experiments, neutralizing anti-TNFalpha antibody was added to the culture. RESULTS: Co-culture of mucosa with bacteria did not modify LDH release. Co-culture with L. casei strains significantly reduced TNFalpha release, whereas E. coli increased it. These effects were observed both in normal and inflamed mucosa. In combination studies, L. casei DN-114 001 prevented TNFalpha stimulation by E. coli. L. casei DN-114 001 also reduced IL-8 release via a TNFalpha-independent pathway. L. casei DN-114 056 or E. coli increased IL-10 release in the presence of neutralizing anti-TNFalpha. CONCLUSIONS: Nonpathogenic bacteria interact with human intestinal mucosa and can induce changes in cytokine production that are strain specific.

Aged↗
PubMed1988

The effects of feeding pelleted diets made from either coarsely or finely ground hay on phosphorus balance and on the partition of phosphorus excretion between urine and faeces in the sheep.

Mature sheep fitted with rumen and duodenal cannulae were fed pelleted diets made from hay that had been either coarsely or finely ground. The diets were supplemented with phosphorus and the effects on salivary phosphorus secretion, net intestinal phosphorus absorption and the route of excretion were examined. Changing the particle size of the diet had no effect on overall phosphorus balance but did affect the route of excretion with urine levels being higher and faecal levels lower in periods when the more finely ground diet was fed. This increase in urine excretion was not due to differences in phosphorus intake nor could it be attributed to increased net phosphorus absorption from the intestine. Salivary phosphorus secretion was, however, lower when the more finely ground diet was fed and it would appear that this change in the balance between that absorbed relative to its secretion back into the gut was the major factor contributing to the increased phosphorus excretion in the urine. The significance of these findings in relation to the high levels of phosphorus normally found in the urine of sheep fed concentrate diets compared to those fed roughage diets is discussed.

Animal Feed↗