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PubMed1989

Effect of antiulcer agents on the physicochemical properties of gastric mucus.

Although the mechanism of gastric mucosal protection is multicomponential, the initial brunt of luminal insult falls on the layer of mucus weakening its physicochemical characteristics and is intimately associated with gastric disease. Hence, the agents capable of strengthening the qualities of mucus gel, associated with its protective function, are becoming increasingly popular in peptic ulcer therapy. Evaluation of the efficacy of these types of drugs requires delineation of their direct effect on the mucus layer constituents, from those evoked in the chemical composition of mucus as a result of prolonged drug administration. Studies with mucus layer strengthening agents indicate that such drugs as sucralfate and De-Nol interact tenaciously with the mucus gel and in essence seal the underlying mucosal surface from the noxious luminal contents. These drugs and other new antiulcer agents like sofalcone, geranylgeranylacetone and stable prostaglandin analogs are also capable of enhancing mucus gel viscosity and its hydrogen ion impedance ability. Furthermore, the majority of these drugs exert an inhibitory effect on peptic degradation of gastric mucus, and the colloidal bismuth preparation (De-Nol) is also capable of prolongation of the luminal availability of epidermal growth factor. The data on gastric mucus gel, following prolonged administration, show that these drugs enhance the lipid content of the mucus gel, and increase both the mucus coat dimension and the proportion of the high molecular weight form of its mucin component. These changes result in the improvement of viscoelastic, permselective and hydrophobic properties of gastric mucus. Hence, continuity of the function of mucus layer perimeter of mucosal defense is maintained.

Anti-Ulcer Agents↗
PubMed2002

[Effect of different nutritional routes on the intestinal mucus barrier in scalded rats].

OBJECTIVE: To observe the effect of different nutritional routes of giving nutrition on the intestinal mucus barrier in severely scalded rats. METHODS: Wistar rats inflicted with 30% TBSA III degree scalding on the back were employed as the model and were randomly divided into 3 groups, i.e. control (C), parenteral nutrition (PN) and enteral nutrition (EN) groups. The rats in PN and EN groups were supplied with equal amount of nitrogen and calories and with equal volume of nutrition solution. The dynamic changes in the thickness of intestinal mucus layer and the contents of protein, hexose and acetylneuraminate in the mucus were examined. RESULTS: When compared with those in C group, the intestinal mucus layer became thinner and the contents of protein, hexose and acetylneuraminate in the mucus in both PN and EN groups decreased evidently after scalding. When compared between two nutritional groups, the thickness of intestinal mucus layer and the contents of the hexose and acetylneuraminate in the mucus in EN were much thicker and higher than those in PN group, while the mucus protein content exhibited no obvious difference between PN and EN groups. CONCLUSION: It was suggested that intestinal goblet cell synthesized and secreted less mucus after scalding in rats resulting in thinning of intestinal mucus layer and the change in mucus components. When compared with those in PN group, less injury to the intestinal goblet cells occurred and the intestinal mucus synthesis was less affected in EN group, and the components of intestinal mucus were maintained stable.

Animals↗
PubMed1982

Influence of osmolality, short chain fatty acids and deoxycholic acid on mucus secretion in the rat colon.

Mucus secretion into the rat colon has been measured in situ using a single perfusion technique. Protein, sialic acid and hexose concentrations in the perfusion solution were found to give reliable estimates of mucus output if samples were homogenized prior to analysis. Mucus output as indicated by an increase in the concentration of mucus constituents was higher when the solution was hypotonic (270 mosm . kg-1) or hypertonic (370 mosm . kg-1) than when isotonic solutions (320 mosm . kg-1) were used. The proportion of hexoses and sialic acid to protein was 23 and 14% at low, 23 and 11% at high osmolality, and 21 and 13% when isotonic solutions were used. Deoxycholic acid (DCA, 4 mmol . 1(-1)) increased the net secretion of mucus constituents 3 fold, whereas short chain fatty acids (SCFA) had no effect. Mucus composition during all treatments did not change significantly, even when stimulated with DCA. When mucus was released from the epithelial surface by previous perfusion with a DCA containing solution, net water and SCFA absorption rates and mucus output were significantly lowered for 2 to 3 h. However, no correlation between mucus secretion and SCFA absorption was found, indicating that a role for mucus as a diffusion barrier to SCFA is unlikely. Mucus output, which indicates the amount of mucus released from the epithelial surface, probably depends on the direction of net water movement, which follows the osmotic gradient between colon lumen and blood.

Animals↗
PubMed1994

The effect of neutrophil protenase enzymes on the release of mucus from feline and human airway cultures.

Neutrophils may be central in the pathogenesis of several airway diseases. The effect of two neutrophil products upon mucus release from feline and human airways was examined in vitro. Neutrophil elastase (HNE) and cathepsin G (HCG) were equipotent in stimulating mucus release from feline trachea. A potential mechanism of the mucus release was studied by exposure to HNE and various inhibitors of serine proteases or eicosanoid metabolism. Coincubation with the serine protease inhibitor, chloromethylketone, completely blocked HNE-stimulated mucus release. The putative selective cyclooxygenase inhibitor, ibuprofen, did not alter HNE-stimulated mucus release. The phospholipase A2 inhibitor, bromophenacyl bromide, and various lipoxygenase inhibitors blocked HNE-stimulated mucus release by 30-40%. The effect of HNE upon mucus release from human upper and lower airways was also examined. HNE stimulated greater mucus release from human bronchi than from nasal mucosa. The cellular source of the mucus was investigated in feline trachea and human upper airway by quantitation of mucus using enzyme assays for a specific mucous cell marker (monoclonal antibody 7F-10). HNE stimulated the release of 7F-10 detectable mucus, and after coincubation with chloromethylketone this stimulation was blocked. These data demonstrate that neutrophil products may alter airway mucus secretion and that altered eicosanoid metabolism may partially mediate these effects. Additionally, the lower airways appear more responsive to HNE than upper airways.

Animals↗
PubMedDate not supplied

Analysis of pre-ovulatory changes in cervical mucus hydration and sperm penetrability.

Changes in cervical mucus occur during the proliferative phase of the menstrual cycle and are known to correlate with receptivity to sperm and to the endocrine milieu. Prior studies, however, have often lacked biological incisiveness and technical objectivity and precision. This study analyzed daily changes in mucus water content (hydration) prior to the LH surge (LH+0) in normal women, in relation to daily levels of serum LH, FSH, estradiol and progesterone, and to daily tests of sperm penetration of the mucus. Cervical mucus was studied for 12 cycles in 10 ovulating women. Three to ten mucus specimens were collected per cycle, over the days LH-8 to LH+0. Each specimen was subjected to measurement of both water content (hydration) and penetration by spermatozoa from fresh specimens of normal human semen. For the latter, a new microscale assay was developed and applied, which was amenable to very small volumes of mucus. The new technique determines objective measures of both the numbers of penetrating sperm (motile and non-motile) and the distance penetrated by the forward most vanguard sperm. In these experiments, variations in semen quality were controlled by performing a companion penetration assay in an artificial 1.5% polyacrylamide gel. The patterns of change in mucus hydration varied quantitatively among women, with preovulatory baseline levels ranging from 93.8-96.5%. All normal cycles (as defined by endocrine profiles) displayed a significant increase in hydration over a one-day period occurring 3-4 days before the LH peak. The magnitude of this shift varied among women between 2 and 3% (absolute hydration), a distinction well within the precision of the hydration assay. This quantum increase in hydration was more pronounced than the corresponding increase in serum estradiol on the same day. The change in mucus hydration, and the associated increase in sperm penetrability, were more consistent among cycles than the changes in reproductive hormones. There was a strong but non-linear correlation between mucus hydration and sperm penetrability. Once the value of hydration rose above approximately 97.5%, there was a substantial increase in penetrability. This 'cut-off point' in sperm penetrability was in the middle of the range of hydration values (across women) which preceded the quantum jump in hydration-which, itself, preceded the surge of LH. Hydration began to increase approximately 2 days before measurable increases in sperm penetration of the mucus in vitro. These results demonstrate that mucus hydration may be a valuable marker of the approach to ovulation and delineation of the fertile period. They also provide new methods for assessing sperm penetration into both large peri-ovulatory and very small samples of collected mucus.

Body Water↗
PubMed1998

The influence of intestinal mucus components on the diffusion of drugs.

PURPOSE: Mucus, a potential diffusional barrier to drug absorption, is a complex mixture of mucin and other components. The objective of this study was to investigate the composition of native pig intestinal mucus (PIM) and the influence of identified mucus components on drug diffusion. METHODS: The mucus components were separated by CsCl-density gradient centrifugation and further analyzed. The self-diffusion coefficients of mannitol, metoprolol, propranolol, hydrocortisone, and testosterone, ranging in lipophilicity from logK = -3.1 to logK = 3.3, were determined, using a small scale tracer technique. The diffusion of drugs in PIM, in solutions or dispersions of individual mucus components, and in an artificial mucus model (MLPD) reconstituted from the major mucus components mucin, lipids, protein, and DNA was compared. RESULTS: The dry weight of pig intestinal mucus contained (%, w/w); mucin (5%), lipids (37%), proteins (39%), DNA (6%), and unidentified materials. The most commonly occurring lipids were free fatty acids, cholesterol, and phospholipids while the most common protein was serum albumin. In PIM, but not in the purified pig gastric mucin (PPGM) solution, the diffusion of the lipophilic drugs metoprolol, propranolol, hydrocortisone, and testosterone was reduced compared to that of the hydrophilic drug mannitol. The diffusion of the lipophilic drugs was also significantly reduced in a dispersion of identified mucus lipids compared to that of mannitol. The diffusion in MLPD was similar to that in PIM for mannitol, propranolol, hydrocortisone, and testosterone, but somewhat lower for metoprolol. CONCLUSIONS: Lipids, rather than mucin glycoproteins, are a major component which contributes to reduced diffusion of drugs in native intestinal mucus. The results suggest that reconstituted artificial mucus models are interesting alternatives to native mucus models.

Animals↗
PubMed1993

Piglet ileal mucus contains protein and glycolipid (galactosylceramide) receptors specific for Escherichia coli K88 fimbriae.

The aim of this study was to characterize the Escherichia coli K88-specific receptors in mucus from the small intestines of 35-day-old piglets with the isogenic strains E. coli K-12(pMK005) (K88+) and E. coli K-12(pMK002) (K88-). These strains differed only in that the latter one cannot produce intact K88 fimbriae because of a deletion in the gene coding for the major fimbrial subunit. Adhesion was studied by incubating 3H-labeled bacteria with crude mucus, pronase-treated whole mucus, mucus fractionated by gel filtration, delipidated mucus, or extracted lipids immobilized in microtiter wells. In addition, E. coli strains were tested for adhesion to glycolipids extracted from mucus by overlaying glycolipid chromatograms with 125I-labeled bacteria. The recently reported finding that K88 fimbriae bind to glycoproteins in mucus from the piglet small intestine was confirmed in two ways. Pronase treatment of immobilized mucus reduced adhesion by 82%, and adhesion to delipidated mucus was 14 times greater for the K88+ than for the K88- strain. E. coli K88+ adhered to several of the fractions collected after gel filtration of crude mucus, including the void volume (M(r), > 250,000). Receptor activity specific for the K88 fimbriae was demonstrated in the lipids extracted from mucus, as the neutral lipids contained six times as much receptor activity as the acidic lipid fraction. Specificity was confirmed by demonstrating that adhesion to the total lipids could be inhibited by pretreatment of the immobilized lipids with K88 fimbriae. Relative to K-12 (K88-), the K-12 (K88+) bacterial cells bound more avidly to galactosylceramide when the neutral lipids were separated on thin-layer chromatography plates. No adhesion to lipids in the acidic fraction separated on thin-layer plates was detected. Relative to adhesion of K-12 (K88-), adhesion of K-12 (K88+) to commercially available galactosylceramide immobilized in microtiter wells confirmed the results with the thin-layer plates. It can be concluded that 35-day-old piglet mucus contains both protein and glycolipid receptors specific for K88 fimbriae, the latter being galactosylceramide.

Animals↗
PubMed1996

Activation of Shiga-like toxins by mouse and human intestinal mucus correlates with virulence of enterohemorrhagic Escherichia coli O91:H21 isolates in orally infected, streptomycin-treated mice.

The enterohemorrhagic Escherichia coli (EHEC) O91:H21 isolates B2F1 and H414-36/89 are virulent in an orally infected streptomycin-treated mouse model. Previous studies demonstrated that B2F1 and H414-36/89 grow to high levels in mucus isolated from mouse small intestine and colon and that growth in small-intestine mucus is related to virulence. We measured the levels of Shiga-like toxins (SLTs) SLT-IIvha and SLT-IIvhb produced by B2F1 after growth in Luria-Bertani (LB) broth supplemented with mouse intestinal mucus by assaying the cytotoxicity of culture supernatants on Vero cells. Culture supernatants from B2F1 grown in mouse intestinal mucus, but not EHEC strains that produce SLT-II or SLT-IIc, were approximately 35- to 350-fold more toxic for Vero cells than supernatants from B2F1 grown in LB broth. This increased toxicity was not reflected by a concomitant increase in SLT antigen content. Furthermore, when culture supernatants from B2F1 or K-12 strains carrying plasmids encoding SLTs cloned from H414-36/89 or purified SLT-IIvhb from B2F1 were incubated with mouse intestinal mucus, the samples exhibited greater cytotoxicity than when they were incubated with N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) buffer alone. These toxin preparations also showed increased cytotoxicity after incubation with human colonic mucus. In contrast, culture supernatants from LB-grown EHEC isolates that produced SLT-I, SLT-II, SLT-IIc or SLT-IIe did not show increased cytotoxicity after incubation with mouse or human intestinal mucus. The A subunits of purified SLT-II and SLT-IIvhb that had been treated with mouse intestinal mucus or trypsin were cleaved to A1 fragments by the mucus, but trypsin-mediated cleavage, unlike treatment with mouse intestinal mucus, did not result in increased Vero cell cytotoxicity activity. This finding implies that the increased cytotoxicity of SLT-IIvhb detected after incubation with mucus is probably not due to cleavage of the A subunit into the A1 and A2 fragments. Taken together, these results indicate that mouse or human intestinal mucus directly activates SLT-II-related toxins from B2F1 and H414-36/89 and suggest that toxin activation may explain the low 50% lethal doses of B2F1 and H414-36/89 in streptomycin-treated mice.

Animals↗
PubMedDate not supplied

Airway mucus in recurrent airway obstruction--short-term response to environmental challenge.

Mucus accumulation and neutrophilic inflammation in the airways are hallmarks of heaves. Endoscopically visible mucus accumulations, however, have not been studied during exposure to dusty hay and allergens (ie, environmental challenge). We hypothesized that (1) heaves-affected horses have increased mucus accumulation compared with controls, (2) mucus accumulations increase in heaves-affected horses during environmental challenge, and (3) environmental challenge also induces neutrophilic inflammation and mucus accumulation in control horses. Mucus accumulation was graded endoscopically (mucus grades [MGs] 1-5), and airway inflammation was evaluated by bronchoalveolar lavage fluid (BALF) cytology before (0 hours) and during (6, 24, 48 hours) environmental challenge. Large amounts of mucus (MG 4-5) were specific for heaves-affected horses in this study. Variation among controls was considerable, however, and intermediate grades (MG 2-3) were nonspecific, showing complete overlap between the 2 groups. Median mucus accumulations (25th, 75th percentiles) increased in heaves-affected horses from MG 2.5 (1.5, 3.5) at baseline to MG 3.5 (2.0, 4.0), 4.0 (3.0, 4.0), and 4.0 (4.0, 4.0) at 6, 24, and 48 hours, respectively. MG values did not increase in controls--overall MG 1.0 (1.0, 2.0)--even though controls also showed a moderate increase of BALF neutrophils. Mucus accumulations before and especially after exposure to dust and allergens are increased in heaves-affected horses compared with controls. Healthy controls show considerable variability in mucus accumulation but, despite an influx of neutrophils into the airways, no increase of mucus accumulation after exposure to hay dust.

Airway Obstruction↗
PubMed1986

The role of mucus in the protection of the gastroduodenal mucosa.

There is good evidence that the adherent mucus plays an important role in the protection of gastroduodenal mucosa from the endogenous aggressors acid and pepsin. Adherent mucus provides a stable unstirred layer which supports surface neutralization of acid by mucosal bicarbonate output and acts as a permeability barrier to luminal pepsin. The adherent mucus layer is continuous. True thickness of the mucus layer and its continuity can only be observed on unfixed sections of mucosa, since histological fixatives and preparation for electron microscopy can cause dehydration and shrinkage of the mucus gel. The structure of adherent gastric mucus is deficient in patients with peptic ulcer disease because of decreased polymerization of the component glycoproteins. This impairment of the mucus barrier is associated with raised amounts of pepsin 1, which digests the mucus layer more aggressively than the major pepsin, pepsin 3, under conditions that pertain both in the stomach (pH 2) and duodenum (pH 4-5). Adherent mucus does not appear to offer much protection against exogenous damaging agents, e.g. alcohol and aspirin. These agents permeate the mucus barrier, damaging the underlying epithelium. The subsequent epithelial repair process is protected by a gelatinous coat over ten times thicker and distinct from the normal adherent mucus layer. Our recent studies show this gelatinous coat to be primarily a fibrin-based gel with mucus and necrotic cells.

Animals↗
PubMed1989

Mucus hypersecretion and viscoelasticity changes in cigarette-smoking dogs.

Chronic cigarette smoke exposure is well known to cause mucus hypersecretion in experimental animals, but the alterations in mucus rheology have not been described. We studied mucus hypersecretion and viscoelasticity changes in nine tracheostomized beagle dogs exposed to cigarette smoke. The dogs were trained to stand quietly in a harness, and smoke was delivered via a cuffed tracheostomy tube. A 35-cm3 bolus was introduced to the inspiratory line each 20 s, using unfiltered 70-mm cigarettes (20 mg tar, 1.2 mg nicotine). Each dog smoked 10 cigarettes per day over 2.5 h, 5 days per week. Two dogs were exposed for 6 months; 7 dogs were exposed for 10 months. Five dogs served as sham-smoking controls. Mucus was collected twice weekly without drugs by resting a cytology brush on the lower trachea for 2-5 min. The rheological properties of the mucus samples were determined by magnetic rheometry, which yields elasticity and viscosity as a function of frequency. The mucus was also weighed, and the galactose content was determined by phenolsulfuric acid assay. The mucus collection rate served as an index of tracheal mucus flux, and the galactose assay as a marker of mucous glycoprotein content. The tracheal mucus linear velocity (TMV) was determined periodically under xylazine analgesia by observing charcoal particle transport bronchoscopically. Eight of 9 smoking dogs developed mucus hypersecretion (flux greater than 2 X control) versus 1 of 5 controls (p less than .01). TMV did not change significantly in 10 months of exposure. In the first 2-4 months of smoking, the elasticity and viscosity of the mucus both decreased (mean at 4 months = 42% control, p less than .001), as did the galactose content (mean at 4 months = 48% control, p less than .01). At this stage, according to model studies, the mucus should have been more easily clearable by ciliary action. After 6 months, the viscoelasticity returned toward the initial control level, while the galactose content remained low, suggesting an alteration in the nature of the mucous glycoprotein.

Animals↗
PubMed1999

Th2-induced airway mucus production is dependent on IL-4Ralpha, but not on eosinophils.

Mucus hyperproduction in asthma results from airway inflammation and contributes to clinical symptoms, airway obstruction, and mortality. In human asthmatics and in animal models, excess mucus production correlates with airway eosinophilia. We previously described a system in which TCR transgenic CD4 Th2 cells generated in vitro were transferred into recipient mice and activated in the respiratory tract with inhaled Ag. Th2 cells stimulated airway eosinophilia and a marked increase in mucus production, while mice that received Th1 cells exhibited airway inflammation without eosinophilia or mucus. Mucus could be induced by IL-4-/- Th2 cells at comparable levels to mucus induced by IL-4+/+ Th2 cells. In the current studies we dissect further the mechanisms of Th2-induced mucus production. When IL-4-/- Th2 cells are transferred into IL-4Ralpha-/- mice, mucus is not induced, and BAL eosinophilia is absent. These data suggest that in the absence of IL-4, IL-13 may be critical for Th2-induced mucus production and eosinophilia. To determine whether eosinophils are important in mucus production, IL-5-/- Th2 cells were transferred into IL-5-/- recipients. Eosinophilia was abolished, yet mucus staining in the epithelium persisted. These studies show definitively that IL-5, eosinophils, or mast cells are not essential, but signaling through IL-4Ralpha is critically important in Th2 cell stimulation of mucus production.

Administration, Inhalation↗
PubMed1992

Role of the physiochemical properties of mucus in the protection of the respiratory epithelium.

The respiratory mucus is a very complex biological material, which possesses both flow and deformation rheological properties, characterized by non-linear and time-dependent viscoelasticity and physical properties of adhesiveness and wettability. Viscosity and elasticity are directly involved in the transport capacity of mucus, whereas wettability and adhesiveness contribute to the optimal interface properties between the mucus and the epithelial surface. Optimal conditions for the protective and lubricant properties of respiratory mucus are represented by high wettability, and adhesiveness high enough not to induce flow of mucus in the respiratory bronchioles under gravity but low enough to mobilize mucus by airflow during coughing. An intermediate viscoelasticity is also required for an optimal mucociliary transport. Different biochemical constituents such as glycoproteins, proteins, proteoglycans and lipids are involved in the gel properties of respiratory mucus. During bronchial infection and particularly in cystic fibrosis, the loss of water and the increase in macromolecules result in a marked increase in viscosity and adhesiveness responsible for the mucus transport impairment. The various lipids present in mucus contribute differently to the physicochemical properties. Surface-active phospholipids, such as phosphatidylcholine and phosphatidylglycerol improve the wettability of mucus, whereas neutral lipids and glycosphyngolipids contribute to the hyperviscosity of mucus during infection. Phospholipids and associated mucins are also implicated in the interaction between bacteria and epithelial cells. Therefore, the respiratory mucus needs appropriate physicochemical properties for the protection, hydration and lubrication of the underlying airway epithelium.

Adhesiveness↗
PubMed1993

Ferret tracheal mucus rheology, clearability and volume following administration of substance P or methacholine.

We studied the effects of substances P administration on tracheal mucus viscoelasticity, water content, clearability and secretion rate. Six neutered adult male ferrets (weight 1.1-1.5 kg) were studied, on four occasions each. They were anaesthetized with ketamine and xylazine, and intubated shallowly. Control mucus (pre- and post-Ringer instillation) was compared with the mucus obtained following instillation of 200 microliters of 10(-6), 10(-5), and 10(-4) M substance P (SP), and 10(-4) M methacholine chloride as a reference. Tracheal mucus was collected by inserting a soft-bristled cytology brush to the level of the carina, and leaving it in contact with the mucosa for 30 min. After withdrawing the brush, the adherent mucus was quickly scraped off and layered with paraffin oil to prevent evaporation. The mucus was analysed for viscoelasticity by magnetic rheometry and solids content by evaporation to dryness. Mucus transportability was assessed by comparison with model gels, and also by means of the frog palate assay, which indicates how well mucus is cleared by normal ciliary action. There was a dose-related increase in mucus volume, and a dose-related decrease in mucus viscosity and elasticity, with substance P administration. Mucus transportability increased with both substance P and methacholine. The effects of 10(-4) SP and methacholine were comparable in terms of viscoelasticity and volume; with both methacholine and SP, there appeared to be an additive effect. The mucus solids content did not correlate with the viscoelastic changes for SP administration, whereas it did for methacholine. These observations suggest that the hypersecretion induced by these two agents might involve different pathways.

Analysis of Variance↗
PubMed1993

Distearoyl phosphatidylglycerol liposomes improve surface and transport properties of CF mucus.

We have previously shown that a decreased level of phosphatidylglycerol in cystic fibrosis (CF) respiratory mucus is partly responsible for its marked adhesiveness and stickiness, which impair mucus transport, and that distearoyl phosphatidylglycerol (DSPG) was the most efficient form of phosphatidylglycerol in the enhancement of respiratory mucus clearance. The aim of our study was to analyse the effect of distearoyl phosphatidylglycerol liposomes on the transport by cough and cilia of cystic fibrosis respiratory mucus. The surface and transport properties of mucus were measured: 1) on native cystic fibrosis mucus; 2) on cystic fibrosis mucus complemented with DSPG liposomes at a non-cytotoxic concentration; and 3) on cystic fibrosis mucus complemented with water. The work of adhesion of cystic fibrosis mucus was significantly decreased by DSPG liposomes, but not by water. For mucociliary transport, the cystic fibrosis mucus was transported at a higher rate with DSPG liposomes and water compared to native cystic fibrosis mucus. The cough clearance of cystic fibrosis respiratory mucus was significantly improved in the presence of DSPG and water, but the effect was more pronounced with DSPG liposomes than with water. We conclude that the use of DSPG liposomes as a lubricating agent proves to be an interesting therapeutic approach for improving the cough and mucociliary transport in cystic fibrosis patients.

Animals↗
PubMed1991

Interactions between Yersinia enterocolitica and rabbit ileal mucus: growth, adhesion, penetration, and subsequent changes in surface hydrophobicity and ability to adhere to ileal brush border membrane vesicles.

Interactions between Yersinia enterocolitica and rabbit ileal mucus were examined. Strains carrying the Yersinia virulence plasmid, pYV, adhered to crude mucus but not to intestinal luminal contents that had been immobilized on polystyrene. Using an Y. enterocolitica O:9 mutant in which the yadA gene (formerly called yopA), encoding the high-molecular-weight outer membrane protein YadA (formerly called protein P1 or Yop1), had been inactivated and an Escherichia coli strain carrying the cloned yadA gene, we demonstrated that the ability to adhere to mucus correlated closely to expression of YadA. Thereafter, we evaluated possible consequences of binding between pYV-carrying Y. enterocolitica O:3 strains and constituents in the mucus layer. pYV-carrying strains were able to multiply at a high rate in mucus but not in luminal contents, and the ability to adhere to mucus could therefore facilitate bacterial colonization of the mucosa. However, we also showed in vitro that mucus acted as a barrier for a mucus-adherent, pYV-carrying Y. enterocolitica strain. Furthermore, penetration through, or preincubation with, mucus reduced subsequent adhesion of the pYV-carrying strain to brush border membrane vesicles without simultaneously causing bacterial aggregation. Preincubation with mucus also changed the bacterial surface of the same strain from hydrophobic to hydrophilic. Immunoglobulins present in mucus did not seem to be of importance for our observations. Interaction of Y. enterocolitica with intestinal mucus may thus reflect a host defense mechanism that reduces the pYV-mediated adhesion to the epithelial cell membrane, possibly by rendering the bacteria less hydrophobic.

Animals↗
PubMed1998

Timing of onset of contraceptive effectiveness in Norplant implant users. Part I. Changes in cervical mucus.

OBJECTIVE: To provide scientific data regarding the changes in cervical mucus within the first hours to days after Norplant implant insertion and to estimate when the cervical mucus is hostile enough to suggest a contraceptive effect. DESIGN: Multicenter, clinical descriptive study. SETTING: Family planning clinics. PATIENT(S): Forty-two women who were between days 8 and 13 of their menstrual cycle and who had requested Norplant implants were admitted to the study. INTERVENTION(S): Cervical mucus and blood samples were obtained. MAIN OUTCOME MEASURE(S): Cervical mucus scores, sperm penetration distances, and serum levels of progesterone, estradiol, and levonorgestrel. RESULT(S): The median cervical mucus score observed at baseline was 6 ("fair"), indicating that the mucus was already somewhat hostile before insertion of the Norplant implants. The median scores declined to 5 at 12 and 24 hours and continued to decrease through day 7 to 2 ("poor"), a score that is judged as hostile to sperm penetration. Overall, 73% of all subjects had a poor cervical mucus score by 3 days after insertion; at 7 days after insertion, 90% exhibited poor mucus and none had a good score. There was a substantial drop in the overall median distance traveled by the vanguard sperm after 12 hours for each cervical mucus score grouping. The distance traveled decreased rapidly between 12 and 24 hours to < 0.5 cm in subjects with fair and poor mucus, and by day 3, 91% of the subjects exhibited poor sperm penetration. CONCLUSION(S): On the basis of our findings, deterioration of the quality of the cervical mucus and sperm penetration is evident by 24 hours after insertion, although not to a level that would suggest adequate protection until 72 hours after insertion. Therefore, we are confident in recommending that backup methods of contraception (e.g, condoms) need not be used for more than 3 days after insertion, even when the implants are inserted close to ovulation. These findings provide policy makers, clinic managers, and clinicians with important information about how they can improve client access to Norplant implants.

Adult↗
PubMed1983

An evaluation of teaching cervical mucus symptoms to ovulating infertile women.

Women (n = 113) with ovulatory menstrual cycles but complaining of infertility were instructed in the observation and charting of cervical mucus symptoms. At the completion of 3 teaching cycles, 80 subjects (70.8%) had successfully charted at least one cycle with an ovulatory mucus pattern (10 subjects became pregnant). Sixty-two (54.9%) of the women continued for a further 3 cycles of investigation during which, around the time of ovulation, an assessment was made of the mucus at the cervix. On the basis of this assessment subjects were classified as either Group 1: charting ovulatory mucus symptoms with 'fertile type' mucus observed at the cervix - 48 subjects (10 became pregnant); Group 2A: charting uninterpretable mucus symptoms but 'fertile type' mucus observed at the cervix - 8 subjects; or, Group 2B: charting uninterpretable mucus symptoms and mucus of poor quality observed at the cervix - 6 subjects. The study shows that infertile ovulating women can be taught to observe and chart their mucus symptoms. Such charting is useful in identifying the fertile period of the cycle for timing of intercourse and for timing of postcoital tests and cervical assessment. It is also useful in identifying the small number of women (5.3%) with an apparent deficiency in mucus production. Whether the 20 subjects (17.7%) who became pregnant were assisted in this objective by their charting of symptoms is unclear.

Body Temperature↗