Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0847097 (acidity)
 15,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glycoproteins were isolated in the contents of two sinus mucoceles by ionic exchange and gel filtration chromatography. These glycoproteins are of the mucin-type and characterized by their richness in carbohydrate, a low amino acid content with a strong proportion of hydroxy amino acids. However, they differ largely by their peptide axis, the length of the carbohydrate chain and their acidity, which is in relation with the presence of sialic acid residue and of sulfate groups. The least acidic mucins are the richest in sialic acid residue and in threonine but have the shortest carbohydrate chains while the most acidic are rich in sulfate, richer in serine and have longer carbohydrate chains. The wall of these two mucoceles has only one type of cell capable of synthetizing the glycoproteins: the epithelium goblet cells revealed by the PAS and the alcian blue at different pH. Glandular formations have never been found in the chorion.
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PMID:[Study of mucins of two sinus mucoceles (author's transl)]. 49 95

The localization of neutral mucin and acidic mucins in both control and fasted rat gastric fundic mucosa were examined by microscopic and electron microscopic histochemical methods. By Carnoy's fixation, the surface mucous coat of the control rat gastric fundic mucosa was found to be composed of alternating layers of acidic mucins and neutral mucin, indicating the synchronous and cyclic secretions of them. In many gastric pits of the fundic glands, the acidic mucins were found to spring out from the deep foveolar regions like volcanoes. This phenomenon may suggest that the acidic mucins play a fundamental role in protecting the pit cells against HCl during its passage, and the layers of neutral mucin and acidic mucins in the surface coat is the safeguard against the HCl and digestive enzymes in the gastric lumen. In the fasting rat gastric fundic mucosa, the acidity and the amount of the gastric juice were markedly decreased, indicating the suppressed secretions of mucins and HCl. The decreased production of sulfomucin was directly demonstrated by 35SO4-autoradiography. Many mucous neck cells existing in close association with the parietal cells were ballooned due to accumulation of alcian blue (AB)-positive but high iron-diamine (HID)-negative sialomucin, which was not demonstrable in the control. The secretory granules of sialomucin contained in the ballooned mucous neck cells were positively stained ultrastructurally with cacodylate-ferric colloid to stain acid mucopolysaccharides.
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PMID:Importance of acidic mucin secretions by foveolar and mucous neck cells of rat fundic mucosa as the defence mechanisms against HCl as revealed by fasting. 138 Aug 50

Intragastric glucose prevents acute stress-induced gastric mucosal injury in the restrained rat. Because increased gastric contractions contribute to mucosal injury in this model and because parenteral glucose infusions have been shown to suppress gastric contractility, we hypothesized that centrally mediated responses to hyperglycemia might contribute to the cytoprotective effect of intragastric glucose. We compared intragastric and intravenous 25% glucose with saline infusions during cold restraint and measured their impact on gastric lesions, serum glucose levels, gastric residual volume (an indirect indicator of net gastric contractility), acidity, and mucin concentration. We found that both intravenous and intragastric glucose infusions increased serum glucose to over 500 mg/dl after 4 hr of stress. Intragastric glucose increased residual volume and gastric pH, as well as decreased gastric mucosal injury, but intravenous glucose had no effects on gastric function. We found that none of the potentially protective effects of intragastric glucose are mediated by central responses to hyperglycemia, and likewise that intravenous glucose has no effect on gastric mucosal injury.
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PMID:Effects of intragastric and intravenous glucose on restraint model of stress ulceration. 147 35

Histochemical properties of mucosubstances in normal mucosa and neoplasms of 100 operated cases with colonic carcinoma were investigated by using several new methods, such as paradoxical concanavalin A (con A) staining and modified PAS reactions for sialic acids. Acidity of goblet cell-type mucin (GCM) of the normal mucosa varied with the depth of the crypt, as well as with different segments of the large intestine, whereas surface coat-type mucin (SCM) mainly consisted of sulfomucin throughout the large intestine. In addition, the PAS reactivity revealing the presence of O-acetylated sialic acid and the labile class III con A reactivity were demonstrated as hallmarks characterizing the colonic GCM. In carcinoma tissues, sialomucin was more abundant than in the normal mucosa. Goblet-type tumor cells were found in 59 cases. Moreover, O-acetylated sialic acid and the labile class III con A reactivity persisted in GCM of the goblet-type tumor cells. GCM of the adjacent mucosa of the neoplasms showed a decrease in sulfomucin in 95 cases and a marked increase in the labile class III con A reactivity in 97 cases, while the histochemical properties of SCM in this region remained unchanged.
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PMID:Mucosubstance histochemistry of the normal mucosa and epithelial neoplasms of the large intestine. 241 Nov 6

50 carcinoid tumors of different locations in the gastrointestinal and respiratory tracts were examined histochemically for mucin production. Isolated discrete aggregates of mucosubstances were identified in a large number of cases (46% of all carcinoid tumors, ranging from 53 to 36% in different organ locations). Acidity and composition of mucosubstances (sulfomucin vs. sialomucin contents) in carcinoids were not different from those described in their corresponding locations. These data support numerous other observations that point to a common stem cell precursor for both enterochromaffin and mucus-secreting epithelial cells in gastrointestinal and respiratory tract mucosal membranes. A shared endodermal derivation is favored over a separate neuroectodermal origin for the chromaffin cell system.
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PMID:Carcinoid tumors with focal mucin production. 264 Aug 95

The comparison of distribution of glycopeptides of sputa from patients suffering from various chronic hypersecretions has already shown an increased acidity with a decreased proportion of neutral glycopeptides in the respiratory secretions of patients suffering from cystic fibrosis, as compared to those of patients with chronic bronchitis. In order to find out whether this decrease is specific to cystic fibrosis mucins or whether it is due to a degradation of mucus by Pseudomonas aeruginosa, which infects most of the sputa from patients with this disease, mucus glycopeptides from patients with different chronic bronchial disorders, infected by Pseudomonas or not, were prepared and fractionated by ion-exchange chromatography. The neutral fraction, which has never been studied in detail, was gel-filtered, and provided two fractions, one containing true mucin glycopeptides and the other containing a mixture of peptides and glycopeptides with a lower molecular mass. In the Pseudomonas-infected samples, the true mucin glycopeptide fraction was greatly diminished as compared to this same fraction in non-Pseudomonas-infected samples; this was not specific to cystic fibrosis secretions. In contrast, the glycopeptide fraction with a lower molecular mass was greatly increased in all the Pseudomonas-infected samples. Polyacrylamide gel electrophoresis of this second fraction showed unique glycopeptide bands between 40-50 kDa in the Pseudomonas-infected samples, regardless of the origin of the samples. These bands were revealed by an antibody directed against whole cystic fibrosis mucin. Infected chronic bronchitis sputa and cystic fibrosis samples without P. aeruginosa did not show these bands. These studies therefore suggest that there are P. aeruginosa-associated changes in mucins which may result from degradation of mucins.
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PMID:Evidence for the in vivo degradation of human respiratory mucins during Pseudomonas aeruginosa infection. 275 44

Ulcer formation after pylorus ligation was assessed in control, testosterone treated and castrated male rats after cimetidine treatment. The stomach was studied for incidence of ulcers and its contents analysed for pH, volume, total acidity, free acidity, pepsin and mucin activity. Testosterone and cimetidine when used alone protected from ulceration while when used in combination the degree of protection was decreased. Castration per se ead no effect on ulcer index but potentiated cimetidine induced gastric ulcer protection.
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PMID:Relevance of male hormonal status with antiulcer effect of cimetidine in pylorus ligated rats. 345 Jun 32

In human saliva, two different mucin populations can be distinguished, viz., high-molecular-weight mucins (MG1, mol. wt > 1 x 10(6)) and low-molecular-weight mucins (MG2, mol. wt approximately 125 kD). The carbohydrate moiety of MG1 displays a wide spectrum of oligosaccharide structures, varying in composition, length, branching, and acidity. The biological significance of the heterogeneity in carbohydrate structures of mucins is unclear. The present investigation focused on the question whether MG1, because of its diverse carbohydrate side-chain population, can bind to a large variety of oral micro-organisms. A replica plate technique, in combination with immunochemical detection with monoclonal antibodies against MG1, was used to screen in vivo human oral microflora for the presence of micro-organisms which could bind the high-molecular-weight salivary mucin MG1. Binding to purified MG1 was established for Hemophilus (para)influenzae species, whereas other species, including Streptococcus and Staphylococcus, were negative. MG1 binding to Hemophilus parainfluenzae could be abolished by protease treatment of MG1. In contrast, periodate acid treatment, partial deglycosylation, or addition of monosaccharides did not affect MG1 binding to H. parainfluenzae, indicating that MG1 carbohydrate side-chains were not directly involved in the binding. The binding was pH-dependent, showing an increase when the pH was lowered from 8.0 to 4.0. These data indicate that MG1 can be bound in a selective manner by Hemophilus spp. and suggest that the 'naked' unglycosylated polypeptide moiety of MG1 is involved in its binding to Hemophilus parainfluenzae.
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PMID:Binding of human high-molecular-weight salivary mucins (MG1) to Hemophilus parainfluenzae. 787 29

Pig gastric mucins were isolated from the surface epithelium of the cardiac region, corpus and antrum using density-gradient centrifugation after extraction in 6 M guanidinium chloride. In CsCl/0.5 M guanidinium chloride, mucins solubilized from the cardiac region appeared as a broad unimodal band at 1.52 g/ml whereas those from the corpus and antrum occurred as high- and low-density populations at 1.50 and 1.45 g/ml respectively. High-iron diamine reacted more strongly with the cardiac mucins and the high-density populations from corpus and antrum than with the two low-density ones. In keeping with this, approx. 60% of the oligosaccharides from the former mucins and 20% from the latter contained sulphate. All surface epithelial cells of the cardiac region stained with high-iron diamine, whereas in the corpus only the epithelium in the bottom of the pits reacted, suggesting that the high-density population from this region originates from these cells. Mucins from all regions were composed of subunits, each containing highly glycosylated domains. The mucins from the cardiac region were larger than those from the corpus and antrum, and reduced subunits as well as high-molecular-mass glycopeptides from the cardiac mucins were larger than the corresponding fragments from the other regions. Ion-exchange HPLC showed that reduced subunits from the cardiac mucins and the high-density populations from the corpus and antrum were more 'acidic' than reduced subunits from the two low-density ones. All mucins contained a 'neutral'fraction, in particular those from the antrum. Pig gastric mucus thus contains a number of distinctly different mucin populations varying in buoyant density, size, 'acidity', glycosylation, sulphation and tissue origin.
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PMID:Mucus glycoproteins from pig gastric mucosa: identification ofdifferent mucin populations from the surface epithelium. 930 44

The biosynthesis of sulfated mucin in gastric tissue was investigated in cold-stress and indomethacin (CSI)-induced gastric ulcer models. To examine the synthesis of gastric sulfated mucin, [35S]H2SO4 (sulfate) incorporation into gastric mucin was measured. The treatment of CSI inhibited the incorporation of [35S]sulfate after 2 hr. The gastric acid hypersecretion or the formation of severe ulcer was observed at 1 or 4 hr after the CSI-treatment, respectively. Pibutidine hydrochloride (IT-066), a novel H2-receptor antagonist, (0.3 mg/kg, s.c.) inhibited the formation of ulcer and reversed the inhibition of mucin sulfation by the CSI-treatment, whereas atropine sulfate, a muscarinic receptor antagonist, (1.0 mg/kg, s.c.) did not inhibit the development of ulcer nor decrease in the mucin sulfation at 6 hr after the CSI-treatment. IT-066 inhibited the total acid output (T.A.O.) due to the reduction of the acidity in the gastric juice, whereas atropine inhibited the T.A.O. due to that of the volume. These results indicated that a different mode of action between IT-066 and atropine on gastric acid secretion influences their actions in the incorporation of [35S]sulfate and the formation of ulcer in the CSI-treated rat. Therefore, it is considered that the reduction of biosynthesis of gastric sulfated mucin following acid hypersecretion may be responsible for the formation of gastric ulcer.
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PMID:Effect of cold-stress and indomethacin on the biosynthesis of gastric sulfated mucin in rats. 946 26


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