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At least 19 recordsLinked to original sources

PubMed1991

A new method of separation and quantitation of mucus glycoprotein in rat gastric mucus gel layer and its application to mucus secretion induced by 16,16-dimethyl PGE2.

A method was established for recovering the mucus gel layer of rat gastric mucosa without damage to underlying surface epithelium. The mucus gel was solubilized by stirring the gastric mucosa in a solution of N-acetylcysteine (NAC), a mucolytic agent. Optimal mucus gel solubilization was possible by treatment with 2% NAC for 5 minutes at room temperature. Mucus glycoprotein was quantitatively extracted and measured from the mucus gel sample obtained by the NAC treatment. This treatment caused no damage to surface epithelial cells, as observed by a light microscope. Besides NAC, pronase solution was also adequate for solubilizing the mucus gel layer without any damage to the surface epithelium. However, extraction and measurement of mucus glycoprotein from the pronase-treated mucus gel sample was not possible due to contamination by high molecular hexose-containing substances which were eluted along with the mucus glycoprotein from the column of Bio-Gel A-1.5m. This NAC method was used to examine changes in mucus glycoprotein content in the mucus gel at one hour following the oral administration of 16,16-dimethyl prostaglandin E2. A significant increase in mucus glycoprotein of the gel was brought about by the prostaglandin treatment. Thus, the present method was suitable for estimating the amount of mucus secreted in to the mucus gel layer.

Animals↗

PubMed1992

Mucin-like high molecular mass protein fractions from total pig gallbladder bile mucus, pig gallbladder wall mucus, and total human gallbladder bile mucus.

Native mucin-like complexes were obtained from both pig gallbladder bile and pig gallbladder wall mucus by precipitation, centrifugation, and gel permeation chromatography. Crude preparations by either dialysis (native mucus from bile, and native gallbladder wall mucus) or by precipitation (crude total bile mucus, and lipomucoid) were purified by gel permeation chromatography on Sephacryl S-300HR and Sephacryl S-500HR (Pharmacia). The elution profiles obtained with a reversibly denaturing and detergent-containing eluent showed the same pattern for all samples, although the amounts of the four main fractions differed somewhat. The excluded fraction with the highest carbohydrate portion had an apparent M(r) > 10(7). This fraction and the following included lipomucoid (in physiological solution tightly bound to fraction I), and an eluent-insoluble mucus portion from all samples were characterized by determination of the protein concentration, carbohydrates, sialic acids, and lipids, using standard methods. Sugar analysis was performed by gas-liquid chromatography. Human gallbladder bile was subjected to the same procedures of mucus precipitation and separation. Human gallbladder bile mucus showed identical behaviour to that of pig gallbladder bile mucus, and showed a very similar elution pattern in gel chromatography.

Animals↗

PubMed1993

Molecular fractionation of gastric mucus component by high-performance liquid chromatography: application to pig gastric mucus in vitro and to human gastric mucus collected by aspiration during gastric endoscopy.

The glycoprotein molecular composition of antral and fundic adherent mucus has been studied by high-performance liquid chromatography on a silica gel column. Preliminary assays with pig gastric mucus allowed us to demonstrate the reproducibility of the method. The mucolytic activity of pepsin on this mucus demonstrates its ability to detect degradation of its glycoprotein components. This method was applied to control the state of pig antral mucosa that has previously been used in an in vitro antacid evaluation procedure, and also study human fundic and antral mucus collected by aspiration from normal and diseased stomachs during upper gastrointestinal endoscopy. Different elution profiles were obtained with these samples, depending on the presence of non-degraded or degraded mucus or due to the lack of mucus on the mucosa.

Adult↗

PubMed2001

Presence of IgM in cutaneous mucus, but not in gut mucus of Atlantic salmon, Salmo salar. Serum IgM is rapidly degraded when added to gut mucus.

In the first part of this study, cutaneous mucus of Atlantic salmon (Salmo salar) was shown to contain IgM, i.e. molecules composed of approximately 72 and 27 kDa subunits and reactive with polyclonal antisera and monoclonal antibodies made against serum IgM. Attempts to detect IgM-like molecules in gut mucus were negative, indicating the IgM is present, at best, in very small amounts. The degradation of serum IgM in mucosal secretions was examined in the second part of this study. Purified IgM from serum was rapidly digested in gut mucus at 4 degrees C. Intermediate 58, 52, 38, 35, 33 and 18 kDa breakdown fragments appeared when analysed in immunoblots. The transient fragments were further degraded to small fragments. HPLC analysis showed that only half of the added serum IgM was intact after 30 min of digestion, and after 4 h intact IgM could not be detected. Serum IgM was not degraded in cutaneous mucus, even after 17 h of incubation.

Animals↗

PubMed1988

Movement of Entamoeba histolytica trophozoites in rat cecum and colon intact mucus blankets and harvested mucus gels.

Entamoeba histolytica trophozoites were centrifuged into mucus gels harvested from in vivo loops of rat cecum and proximal colon. Frank ameba movement was not detected in the colonic mucus, but attenuated motility was measured in the cecal mucus. The harvested rat cecal mucus had significantly lower apparent viscosity and neutral glycoprotein concentration values than the colonic mucus. A shape factor method was developed to assess the motility of amebae in mucus gels and intact mucus blankets. Shape factor data obtained from harvested mucus gel and intact mucus blanket experiments indicated that such mucus severely attenuated trophozoite movement with the attenuation being greater with colonic than with cecal mucus. Entamoeba trophozoites are known to be able to generate a pseudopod force of 3.3 x 10(-6) Newtons. Latex microspheres of the size range of Entamoeba trophozoites were forced through cecal and colonic mucus gels under gravity. Colonic mucus gels could withstand a force of 3.3 x 10(-6) Newtons while cecal mucus could not, suggesting that the ameba movement that was observed in cecal mucus involved mechanical penetration of the mucus by the ameba pseudopodia and did not require prior gel dissolution by Entamoeba enzymes.

Animals↗

PubMed1986

Misoprostol-induced increases in adherent gastric mucus thickness and luminal mucus output.

Gastroduodenal mucus can be separated into two phases: insoluble mucus gel adherent to the mucosal surface, and luminal mucus, which is removed by washing out the lumen. The adherent mucus gel is part of the mucosal protective barrier to acid and pepsin in the gastric juice. Luminal mucus, which is mobile, probably does not significantly protect against gastric juice, but functions as a lubricant, protecting the adherent mucus layer and underlying mucosa from mechanical damage. Adherent mucus is observed on the mucosal surface as a thin, continuous, gelatinous layer of variable thickness, about 50-450 microns (median, 180 microns) in man and 10-230 microns (median 80 microns) in the rat. Thickness of this adherent mucus layer in the rat stomach is increased significantly (up to threefold) following topical administration of misoprostol in vivo 1 hr before measurement. Simultaneous increases are observed in the content of luminal mucus following misoprostol administration. Seventy percent of maximum response is observed within 5 min of topical prostaglandin administration, compatible with the release of preformed mucus. Such prostaglandin-stimulated increases in mucus thickness will improve the protective capacity of the adherent mucus gel. The thickness of the adherent mucus layer is not changed following topical exposure, in vivo 1 hr before measurement, to exogenous mucosal-damaging agents (eg, ethanol, indomethacin and taurocholate. However, since such damaging agents permeate the mucus gel, it appears to offer little initial protection to the underlying epithelium. The mucus barrier primarily guards against the natural aggressors acid and pepsin, protecting the epithelium and its repair following acute mucosal damage.

Alprostadil↗

PubMed1985

Properties of gastric and duodenal mucus: effect of proteolysis, disulfide reduction, bile, acid, ethanol, and hypertonicity on mucus gel structure.

Small deformation oscillatory rheologic measurements have been used to investigate the structure of human and pig gastric mucus and pig duodenal mucus. All three secretions had viscoelastic properties characteristic of water-insoluble, viscoelastic gels. Mucus will flow and anneal if damaged, due to the making and breaking of its elastic structure, the measured lifetime of which was 10-120 min. Mucus reconstituted by concentration of the purified glycoprotein (pig gastric and duodenal mucus) had the same viscoelastic properties as the fresh mucus, giving evidence that the glycoprotein alone will reproduce the rheologic characteristics of the mucus. The structure of fresh mucus gel was unaffected by prolonged exposure to the following mucosal damaging agents: undiluted pig bile, 20 mM sodium taurocholate or 20 mM sodium glycocholate (all at pH 2, 6, and 8), HCl at pH 1, 2 M NaCl, and ethanol less than 40% (vol/vol). Higher concentrations of ethanol greater than 40% (vol/vol), caused dehydration and denaturation of mucus. Proteolysis by pepsin and other enzymes resulted in solubilization of the mucus gel with a complete change in the properties from an "elastic" gel to those of a "viscous" liquid. A similar collapse of mucus gel structure was observed after reduction of disulfide bonds in 0.2 M mercaptoethanol, but only after incubation for at least 50 min. This study demonstrates the stability of mucus to several mucosal damaging agents. It is proposed in vivo that although adherent gastroduodenal mucus allows penetration of these agents to the underlying mucosa, it can remain in situ and continue to protect against acid (with HCO3-) and pepsin, thus minimizing mucosal damage and maximizing repair.

Animals↗

PubMed1984

Mucus glycoprotein structure, gel formation and gastrointestinal mucus function.

Gastrointestinal mucus occurs as a water-insoluble gel adherent to the mucosal surfaces and as a viscous, mobile solution in the lumen. The adherent gastroduodenal mucus gel is part of the mucosal defence against acid (with HCO3-), pepsin (diffusion barrier) and mechanical damage. Rheological studies show that gastrointestinal mucus is a weak, viscoelastic gel. The size and physical properties of the isolated component glycoproteins depend critically on the methods used to obtain them. A glycoprotein preparation of Mr approximately 2 X 10(6), which possesses the gel-forming properties of the native mucus, is considered to represent the secreted covalent entity in pig gastric and small intestinal mucus. These glycoproteins have a polymeric structure of subunits joined by disulphide bridges between non-glycosylated regions of their protein cores. Glycoprotein polymerization, essential for gel formation, is deficient in gastric mucus in peptic ulcer disease. In vivo, adherent mucus gel forms a thin but continuous cover of variable thickness (rat 5-500 microns) over the gastroduodenal mucosa. Luminal pepsin rapidly dissolves this mucus cover and its continuity is maintained by fresh mucus secretion. Bile, HCl, 2 M-NaCl and ethanol (less than 40%) do not destroy mucus gel structure. Prostaglandins and carbachol increase mucus thickness, affording better protection, but it is thought that continuity of the protective mucus cover is the critical factor in its protective functions.

Animals↗

PubMed1988

Cholera enterotoxin-induced mucus secretion and increase in the mucus blanket of the rabbit ileum in vivo.

The in vivo rabbit ileum was used to study the relationship of cholera enterotoxin-induced water and electrolyte secretion and mucus secretion and to determine whether the enterotoxin influenced the intestinal mucus blanket. In experiments in which luminal fluid viscosity was used to assess mucus secretion, it was found that while cholera enterotoxin induced a sustained secretion of water and electrolytes, the toxin-induced mucus hypersecretion was short lived (3 to 5 h) and subsequent exposure of the mucosa to cholera enterotoxin or prostaglandin E1 did not stimulate mucus secretion further. Dibutyryl cyclic AMP and theophylline caused a modest mucus secretion in ileal loops which differed from that of cholera enterotoxin in both magnitude and in the fact that the mucus secretion occurred 2 to 3 h after the onset of water and electrolyte secretion. An oral replacement solution was used in the ileum to reduce the enterotoxin-induced loss of water and electrolytes into the lumen. While such a solution slowed the appearance of acidic glycoprotein in the intestinal lumen, it did not change the amount of glycoprotein secreted over a 7-h period, suggesting that toxin-induced mucus secretion was not simply due to a flushing action of the experimentally caused diarrhea. To assess mucus blanket thickness, neutral glycoprotein was recovered from the blanket of rabbit ileal loops 7 h after exposure to cholera enterotoxin and the thickness of the mucus blanket was measured directly 4 and 18 h after toxin exposure. Both methods indicated that even though cholera enterotoxin-induced mucus hypersecretion had subsided and there was histological evidence of goblet cell mucin depletion, there was a sustained increase in mucus blanket thickness that was detectable for at least 18 h after mucosal enterotoxin exposure.

Animals↗

PubMed1999

The chemotactic response of Vibrio anguillarum to fish intestinal mucus is mediated by a combination of multiple mucus components.

Chemotactic motility has previously been shown to be essential for the virulence of Vibrio anguillarum in waterborne infections of fish. To investigate the mechanisms by which chemotaxis may function during infection, mucus was isolated from the intestinal and skin epithelial surfaces of rainbow trout. Chemotaxis assays revealed that V. anguillarum swims towards both types of mucus, with a higher chemotactic response being observed for intestinal mucus. Work was performed to examine the basis, in terms of mucus composition, of this chemotactic response. Intestinal mucus was analyzed by using chromatographic and mass spectrometric techniques, and the compounds identified were tested in a chemotaxis assay to determine the attractants present. A number of mucus-associated components, in particular, amino acids and carbohydrates, acted as chemoattractants for V. anguillarum. Importantly, only upon combination of these attractants into a single mixture were levels of chemotactic activity similar to those of intestinal mucus generated. A comparative analysis of skin mucus revealed its free amino acid and carbohydrate content to be considerably lower than that of the more chemotactically active intestinal mucus. To study whether host specificity exists in relation to vibrio chemotaxis towards mucus, comparisons with a human Vibrio pathogen were made. A cheR mutant of a Vibrio cholerae El Tor strain was constructed, and it was found that V. cholerae and V. anguillarum exhibit a chemotactic response to mucus from several animal sources in addition to that from the human jejunum and fish epithelium, respectively.

Animals↗

PubMed1991

Cervical mucus score and in vitro sperm mucus interaction in spontaneous and clomiphene citrate cycles.

OBJECTIVE: Assessment of the effects of clomiphene citrate (CC) on cervical mucus score and in vitro sperm mucus interaction. DESIGN: Prospective study of cervical mucus score and in vitro sperm mucus interaction in a spontaneous cycle followed by a CC cycle to compare paired data. SETTING: Tertiary institutional infertility clinic. PATIENTS, PARTICIPANTS: Twenty-two couples with primary unexplained infertility were studied in both cycles. INTERVENTIONS: Clomiphene citrate (150 mg) on days 5 to 9 in CC cycles. MAIN OUTCOME MEASURES: Cervical mucus score and sperm-mucus penetration test score. RESULTS: Mean cervical mucus score in spontaneous cycles was 9.3 (95% confidence interval [CI] 8.4 to 10.2) and in CC cycles 5.6 (95% CI 4.6 to 6.6), P less than 0.0001. Sperm-mucus penetration test score in spontaneous cycles was 11.4 (95% CI 7.6 to 15.2) and in CC cycles 3.9 (95% CI 1.17 to 6.63), P less than 0.01. CONCLUSIONS: Clomiphene citrate has an adverse effect on both cervical mucus score and sperm-mucus penetration.

Adult↗

PubMedDate not supplied

Methods for studying respiratory mucus and mucus clearance.

We describe some basic procedures for studying the properties of mucus. These techniques can be applied in both clinical and physiological studies to improve the understanding of the mechanisms related to epithelial defense in health and disease. Mucus collection--A major difficulty is the lack of simple and noninvasive methods for collecting normal mucus in sufficient quantity for later analysis. Physical properties of mucus--A. Rheology: Mucus exhibits both solid and liquid properties and the important factor governing the actual behavior is time. The magnetic microrheometer provides an elegant method for measuring rheological properties of microsamples. B. Adhesivity: It characterizes the forces of attraction between an adherent surface and an adhesive system and can be calculated by measuring the contact angle between a mucus drop and a surface. Mucus Transport--A. Mucus transport by cilia: Mucus is primarily cleared by the continuous ciliary beating, which can be studied using techniques such as the frog palate preparation as well as direct measurement, i.e., in situ mucus clearance. B. Cough clearance: It is essential for elimination of secretions in diseases leading to hypersecretory states. The cough machine simulates the flow-time profile of human coughing. Transepithelial potential difference--A potential difference exists between the epithelial surface and the submucosa and is the net result of the activity of the ion-transport system of the pulmonary epithelium. The potential can be measured using appropriate microelectrodes. Quantitative morphology--Methods may be used to characterize the epithelial surface condition that continuously changes during aggressive conditions.

Animals↗

PubMed1995

Adaptive cytoprotection in cultured rat gastric mucus-producing cells. Role of mucus and prostaglandin synthesis.

In cultured gastric mucosal cells, we investigated whether: (1) adaptive cytoprotection was associated with stimulation of endogenous prostaglandin synthesis; (2) prostaglandins given exogenously were cytoprotective against ethanol-induced gastric mucosal cell damage; and (3) a relationship existed between cytoprotection and mucus release. Cytolysis was quantified by measuring 51Cr release from prelabeled cells. Mucus release was determined by measurement of [3H]glucosamine release. Concentrations of ethanol > 12% caused cell damage and increased 51Cr release dose dependently. Pretreatment with low concentrations of ethanol (0.5-1.5%) decreased ethanol-induced 51Cr release, but also decreased prostaglandin E2 synthesis. Prostaglandin E2 and 16,16-dimethyl prostaglandin E2 given exogenously were cytoprotective against ethanol-induced gastric mucosal cell damage. Treatment with low concentrations of ethanol (1.5%) increased mucus release from cultured gastric mucosal cells. However, prostaglandin E2 and 16,16-dimethyl prostaglandin E2 did not affect mucus release. We conclude that in cultured gastric mucus-producing cells: (1) adaptive cytoprotection occurs without stimulation of endogenous prostaglandin synthesis but with increase in mucus release; and (2) exogenous prostaglandins are cytoprotective against ethanol-induced gastric mucosal cell damage without stimulating mucus release in vitro. We postulate that adaptive cytoprotection in cultured gastric mucus-producing cells is not mediated by prostaglandin, but by mucus released in response to a mild irritant.

16,16-Dimethylprostaglandin E2↗

PubMed1989

Physico-chemical characteristics of mucus glycoproteins and lipids of the human oral mucosal mucus coat in relation to caries susceptibility.

Mucus coat was isolated from oral epithelial surfaces of caries-resistant and caries-susceptible subjects, analysed for content and composition of lipids and mucus glycoproteins, and evaluated for physico-chemical characteristics. The mucus coat from caries-resistant subjects had a protein content similar to that of the caries-susceptible group but a higher content of carbohydrate and a lower content of lipids and covalently bound fatty acid. The carbohydrate component was mainly mucus glycoprotein, which accounted for 28.4% of the dry weight of caries-resistant mucus and 25.3% of caries-susceptible mucus. By chromatographic analysis on Bio-Gel A-50, both types of preparations had high (Mr approximately 2000 kdalton) and low (Mr approximately 300 kdalton) molecular-weight mucus glycoproteins. In the caries-susceptible mucus coat these two glycoproteins were in similar proportions, whereas the low molecular-weight glycoprotein predominated in caries-resistant mucus. In both preparations, the high molecular-weight glycoprotein was characterized by a high content of carbohydrates, associated lipids and covalently bound fatty acids, whereas the low molecular-weight glycoprotein was richer in protein and contained lesser amounts of associated and covalently bound lipids. Although the low molecular-weight glycoprotein showed only minor compositional differences with caries status, the high molecular-weight glycoprotein of the caries-resistant group had a 2.5 times lower content of covalently bound fatty acid, a 1.3 times lower content of associated lipids and contained 1.2 times more sulphate and sialic acid then that of the caries-susceptible group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1997

Induction of airway mucus production By T helper 2 (Th2) cells: a critical role for interleukin 4 in cell recruitment but not mucus production.

Airway inflammation is believed to stimulate mucus production in asthmatic patients. Increased mucus secretion is an important clinical symptom and contributes to airway obstruction in asthma. Activated CD4 Th1 and Th2 cells have both been identified in airway biopsies of asthmatics but their role in mucus production is not clear. Using CD4 T cells from mice transgenic for the OVA-specific TCR, we studied the role of Th1 and Th2 cells in airway inflammation and mucus production. Airway inflammation induced by Th2 cells was comprised of eosinophils and lymphocytes; features found in asthmatic patients. Additionally, there was a marked increase in mucus production in mice that received Th2 cells and inhaled OVA, but not in mice that received Th1 cells. However, OVA-specific Th2 cells from IL-4-deficient mice were not recruited to the lung and did not induce mucus production. When this defect in homing was overcome by administration of TNF-alpha, IL-4 -/- Th2 cells induced mucus as effectively as IL-4 +/+ Th2 cells. These studies establish a role for Th2 cells in mucus production and dissect the effector functions of IL-4 in these processes. These data suggest that IL-4 is crucial for Th2 cell recruitment to the lung and for induction of inflammation, but has no direct role in mucus production.

Adoptive Transfer↗

PubMed1996

Comparative study of the effect of human cervical mucus and a cervical mucus substitute, Healonid, on capacitation and the acrosome reaction of human spermatozoa in vitro.

The present study was designed to investigate the effect of human cervical mucus on capacitation and the acrosome reaction of human spermatozoa and compare its effect to that of a cervical mucus substitute, sodium hyaluronate (Healonid). Spermatozoa from donors of proven fertility were isolated from semen using cervical mucus, Healonid or a direct swim-up (acting as the control). Sperm capacitation and the acrosome reaction were monitored by the chlortetracycline assay. In the mucus-treated group, there was a significantly higher percentage of capacitated spermatozoa, but a low incidence of spontaneous and A23187-induced acrosome reactions compared to the control. The use of Healonid during sperm isolation mimicked the effect of mucus relatively successfully. Since mucus and Healonid show very little chemical similarity, this finding would imply that cervical mucus exerts a physical effect during its interaction with spermatozoa, although a chemical effect cannot be completely dismissed. In conclusion, this study confirms early reports describing the ability of cervical mucus to capacitate spermatozoa but at the same time conserve sperm function. The finding that Healonid exerts an almost identical effect on spermatozoa would lend support to its use as a cervical mucus substitute during in-vitro fertility assessments and research studies.

Acrosome↗

PubMed1984

Comparison of the in vitro sperm penetration test using human cervical mucus and bovine estrus cervical mucus with the postcoital test.

The objective of this study was to determine how well bovine estrus cervical mucus could be substituted for human cervical mucus in the in vitro sperm penetration test (SPT) and how well the SPT compares with the postcoital test (PCT). The subjects were couples chosen at random from our infertility clinic population. The complete infertility evaluation of these couples included a PCT performed at the time of anticipated ovulation. Human cervical mucus quality was assessed using a scoring system which evaluated amount, spinnbarkeit, ferning, viscosity, and cellularity. SPT's were performed in flat capillary tubes filled with cervical mucus and exposed to semen samples for 90 minutes. Thirty-five couples had SPT's performed with wife's mucus and bovine mucus. Test results showed that PCT results correlated significantly with the SPT (P 0.02) but r was low (r = 0.37). The cervical mucus score correlated well with the SPT (P 0.001, r = 0.52) but less well with the PCT (P 0.03, r = .30). It is concluded that the SPT performed with either wife's mucus or bovine mucus is not an adequate substitute for the PCT but provides complementary information.

Animals↗

PubMed1980

Sperm penetration into cervical mucus in vitro. II. Human spermatozoa in bovine mucus.

Human spermatozoa pentrate estrous bovine cervical mucus readily in vitro and maintain good motility and viability for a number of hours. They show pronounced unidirectional motion in mucus that has been aligned linearly. Data from tube preparations indicate that human spermatozoa from a given ejaculate travel more rapidly in estrous bovine mucus than in human midcyle mucus. They are prevented from penetrating luteal phase bovine mucus. The results are discussed in relation to a model of the molecular structure of cervical mucus, derived from laser light-scattering spectroscopy. In addition, it is suggested that bovine cervical mucus could be developed as a possible substitute for human cervical mucus in cases of infertility due to deficient endogenous mucus.

Animals↗