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At least 19 recordsLinked to original sources
PubMed1979

Human cervical mucus. V. Oral contraceptives and mucus rheologic properties.

Mucus viscoelasticity on individual samples obtained from patients using combination oral contraceptives was quantitated by microrheometry. These results, in conjunction with mucus chemical characterization, indicate that combination oral contraceptive use eliminates the cyclic variations in mucus chemical, physicochemical, and rheologic properties associated with the ovulatory menstrual cycle. A correlation was demonstrated between the mucus elastic modulus and mucus nondialyzable dry weight, and the mucins produced during oral contraceptive therapy were shown to be similar to those recovered from ovulatory donors. Differences in mucus properties were noted when donors using estrogenic contraceptives were contrasted with those using androgenic contraceptives. On the basis of established relationships between sperm penetrability and mucus solids content, it was concluded that the use of contraceptives, as examined in this study, provided a secondary degree of fertility control at the cervical level.

Cervix Mucus↗
PubMed1977

Immunoglobulins, proteinase inhibitors, albumin, and lysozyme in human cervical mucus. I. Communication: hormonal profiles and cervical mucus changes--methods and results.

The serum levels of luteinizing hormone (LH), estradiol-17beta, and progesterone were determined simultaneously with the concentrations of immunoglobulin (Ig) G, IgA, C'3, alpha1-antitrypsin, inter-alpha-trypsin inhibitor, alpha1x-antichymotrypsin, albumin, and lysozyme in cervical mucus during nine ovulatory cycles. Spinnbarkeit and ferning were also assessed, and the basal body temperature was measured and recorded during these cycles. The profiles were synchronized according to the LH peak. The midcycle period, characterized by the rapid increase and decline of estrogen and the beginning rise of progesterone, shows a prounced minimum of immunoglobulins, C'3, proteinase inhibitors, albumin, and lysozyme in cervical mucus, which is known to be most receptive to sperm penetration at this time. Although the variation of cervical mucus values is considerable during the early proliferative and the luteal phases, the midcycle values appear to be constantly low, showing slight differences among the profiles of the different parameters. The statistical evaluation and the assessment of the significance of parameters for ovulation detection and the assessment of the fertile period as well as the correlation of these parameters with basal body temperature will be the subject of the second communication of this series.

Adult↗
PubMed1975

Results of in vitro sperm penetration tests in cervical mucus in the normal cycle and in mucus under the influence of the contraceptive pill.

Women who are either menstruating normally or taking a combined or sequential preparation for hormonal contraception were examined at intervals of 2 days with reference to the day of the cycle. The parameter studied was the in-vitro penetrability of the cervical mucus for sperms. Whilst the combined preparation completely blocked the cervical canal for the spermatozoa, the distance travelled by the spermatozoa under the influence of the sequential preparation was approximately the same as in the normal cycle. This study of the depth of penetration of the spermatozoa in relation to the hormonal situation was prompted not by contraceptive but rather by epidemiological considerations of cervical carcinoma.

Cervix Mucus↗
PubMed1979

Mechanisms of mucus release in exposed canine gastric mucosa.

Mucus release was studied in the exposed gastric mucosa of anesthetized fasted dogs using scanning and transmission microscopy as well as histochemical and autoradiographic techniques. Under unstimulated conditions, the gastric epithelium was composed of both nonsecreting and mucus-secreting epithelial cells, with the former being predominant. Nonsecreting cells were characterized by an intact apical mucus package of granules and a continuous plasma membrane. The secreting mucus cell population was found in the foveolar (pit region) as well as interfoveolar areas. Three mechanisms of mucus release were observed: (a) exocytosis, (b) apical expulsion, and (c) cell exfoliation. Evidence for exocytosis was found in all mucus cells, especially in the sulfated glycoprotein-rich foveolar cells. Exocytosis involved only a few granules at a time; this mode of secretion is likely slow and continuous. In contrast, apical expulsion resulted in an explosive release of the entire apical mucus package followed by in situ degeneration of the cell itself. This occurred in the oldest cells forming mucosal crests in the interfoveolar area, whose mucus predominantly stains for neutral glycoproteins. Cell exfoliation, in which the entire cell was extruded into the lumen, was rarely observed and may provide, in addition to apical expulsion, a second mechanism to rid the mucosa of senescent epithelial cells. Mucus secretion is a complex function of the gastric epithelium. The mechanism of secretion and the histochemically defined type of mucus secreted are variables which are dependent on the age of the cell, its position on the foveolae, and the microenvironment within the gastric lumen. The mucus-containing surface and pit cells of gastric epithelium have been described morphologically and ultrastructurally in a number of studies. These cells are highly differentiated, forming a layer which is dynamic and responsive to conditions present in the gastric lumen. Mucus cells arise from multipotent progenitor cells which differentiate in the course of migration up the gastric pits and are involved in the complex macromolecular synthesis of glycoproteins. Although mucus release occurs throughout cell life, very little attention has been given to the cellular ultrastructural changes that deal with mucus secretion. As a result, the mucus-containing surface and pit cells have been described primarily in terms of their nonsecreting functional state. Exceptions to this are a few transmission and scanning electron microscopy studies which describe loss of intact mucus granules, cell extrusion, and in situ degeneration. These previous ultrastructural studies describe cellular patterns, in both normal and injured mucosa, which we fell are related to mucus release. Because of a paucity of knowledge concerning the normal mechanisms of mucus secretion, it was the purpose of this study to define the ultrastructural changes which result in and accompany the production of mucus in canine gastric epithelium.

Animals↗
PubMed2026

Physical, chemical, and structural properties of human gastric organoid-derived mucus.

The gastric mucus layer protects the epithelium from gastric acid and ingested pathogens. However, studies of human gastric mucus have been limited due to poor accessibility of native human mucus and the abundance of contaminants in these samples. Here, we explored the potential of human gastric organoids as models for mucus production. Immunofluorescence staining confirmed that the organoids produced mucus containing MUC5AC and MUC6. The luminal mucus had viscoelastic properties similar to those of native human gastric mucus, as determined by particle tracking microrheology. To collect organoid-produced gastric mucus, termed bioengineered gastric mucus (BGM), organoids were cultured as monolayers at the air-liquid interface (ALI), and apically secreted mucus was harvested and analyzed by MUC5AC ELISA, proteomics, cryo-field emission scanning electron microscopy (CryoFE-SE), and rheometry. BGM contained high-molecular weight molecules also found in native gastric mucus. Proteomic analysis confirmed that BGM contained MUC5AC, MUC6, MUC1, and other stomach-specific molecules such as pepsin C, trefoil factor 2, and gastrokine. CryoFE-SE showed that both BGM and native mucus had a porous structure and a characteristic honeycomb scaffold. However, the viscosity of the BGM was generally lower than that of native human gastric mucus, and BGM failed to exhibit gelation at low pH. Collectively, these findings demonstrate the potential as well as some limitations of BGM as an accessible model system for human gastric mucus.NEW & NOTEWORTHY We demonstrate the structural and functional similarities of organoid-derived gastric mucus and native mucus collected from human patients. The bioengineered gastric mucus mimics its native counterpart in its proteomic profile and physical architecture. This work highlights the translational potential of organoid-derived mucus for functional investigations of the human gastric mucus layer.

Humans↗
PubMed1992

Affinity for porcine respiratory tract mucus is found in some isolates of Actinobacillus pleuropneumoniae.

The ability of 17 Actinobacillus pleuropneumoniae isolates representing serotypes 1, 2, 5, and 7, to adhere in vitro to porcine respiratory tract mucus was examined. Adherence of bacteria to crude mucus preparations was evaluated by use of a dot-blot assay and an enzyme immunoassay. Seventy per cent (12/17) of the isolates of A. pleuropneumoniae had affinity, to various degrees, for porcine respiratory tract mucus. No relationship was found between affinity for respiratory mucus and serotype, haemagglutination, lipopolysaccharide (LPS) profiles, or adherence to porcine tracheal rings. However, a correlation was found between affinity for respiratory mucus and capsular material thickness; heavily encapsulated isolated showed no or less affinity for mucus than isolates with a thinner layer of capsular material. Moreover, two encapsulated isolates showed less affinity for mucus than their acapsulated variant. Finally, the affinity of A. pleuropneumoniae for respiratory mucus was heat- and proteinase-K-resistant. Our data suggest that capsular material of A. pleuropneumoniae could mask a surface component, possibly LPS, which has affinity for porcine respiratory mucus.

Actinobacillus Infections↗
PubMed1992

Role of mucus in mucosal protection through ethanol and pepsin damage models.

Gastrointestinal mucus is considered an important part of the mucosal defence mechanism against endogenous aggressors such as acid and pepsin. The mucus gel layer, adherent to the mucosal surface creates a diffusion barrier to luminal pepsin, thus protecting the underlying epithelium from the digestion by pepsin. The mucolytic pepsin will, however, digest the mucus at its luminal surface, but that lost is normally balanced by secretion of new mucus. This dynamic balance is disrupted when the mucus is exposed to excess pepsin, which causes focal haemorrhagic damage by progressively hydrolyzing the adherent mucus. The adherent mucus gel layer cannot contribute to the protection against exogen damaging agents such as ethanol and nonsteroidal anti-inflammatory drugs, as these compounds easily penetrate the mucus barrier causing, at high concentration, epithelial exfoliation. This study describes the basic properties and characteristics of gastric mucus and compares the pepsin-induced damage with the ethanol damage model.

Animals↗
PubMed1979

Effect of pentobarbital anesthesia on rheology and transport of canine tracheal mucus.

Tracheal mucus samples were collected from six tracheostomized dogs before and after induction of pentobarbital anesthesia. The dynamic mechanical properties of the mucus were determined by the magnetic microrheometer technique. In 15 experiments, the mean value of elasticity at 1 rad/s rose from 67 dyn/cm2 before anesthesia to 212 dyn/cm2 in the period 15-90 min after induction. At the same time, mean viscosity at 1 rad/s rose from 24 to 79 P. The mucociliary transportability of some of the mucus samples was assayed by means of in vitro frog palate technique. In 10 experiments, the relative transport rate for dog tracheal mucus went from 98% of frog palate control befor anesthesia to 79% during pentobarbital anesthesia. A negative relationship between from palate transport rate and mucus elasticity was found. A negative correlation between transport and mucus viscosity at constant elasticity was also discovered. Finally, the mucus collection rate was reduced by a factor of about 8 during anesthesia, suggesting a reduction in the average depth of mucus.

Animals↗
PubMed1992

Effect of rebamipide on mucus secretion by endogenous prostaglandin-independent mechanism in rat gastric mucosa.

The effect of rebamipide (2-(4-chlorobenzoylamino)-3-[2 (1H)-quinolinon-4-yl]-propionic acid, OPC-12759, CAS 11911-87-6), an anti-ulcer agent developed to enhance defensive factors in the gastric mucosa, on gastric mucus secretion was studied by a newly developed biochemical method to measure the gastric mucus glycoprotein content in rats. 1 h after intraperitoneal administration, rebamipide did not produce a significant change in the intramucosal mucus contents (surface mucosal layer and deep mucosal layers of corpus and antral regions) but significantly increased the content of soluble mucus, which recovered from the gastric contents, to about 160% of the control value. Since rebamipide has been shown to increase the biosynthesis of prostaglandins, indometacin was administered to the rats prior to rebamipide administration to examine whether the increase in prostaglandin biosynthesis contributes to the rebamipide-induced increase in gastric mucus secretion. The increase in the soluble mucus was not altered by the pretreatment with indometacin, thus indicating that rebamipide per se has a potential to increase the gastric mucus secretion by a mechanism that is not mediated by the endogenous prostaglandins. The effect of rebamipide on the gastric mucus secretion might contribute to heal and to prevent the recurrence of peptic ulcer diseases as well as to maintain the homeostasis of the gastric mucosa.

Alanine↗
PubMed1977

Human cervical mucus. I. Rheologic characteristics.

The viscoelastic properties of human cervical mucus were subjected to detailed characterization by microrheometry. An introduced to the range of parameters that can be measured and the sensitivity of microroheometry to variations in mucus viscoelasticity was presented, along with an interpretation of results obtained by this approach. Fresh cervical mucus samples were shown to be rheologically heterogeneous, reflecting compositional differences in situ. Mucas viscoelasticity was stable for several hours when samples were stored at ambient temperature in the microrheometer sample holder. Mucus viscoelasticity was strongly dependent upon nondialyzable solids (NDS) concentration. In order to eliminate (NDS) as a variable in comparative studies of mucus, procedures were developed for reconstitution of mucus at identical (NDS) or for normalization of viscoelasticity data derived from fresh samples to 2.5% NDS. The validity of this approach was then examined by applying these procedures to mucus collected during the follicular, ovulatory, and luteal phases of the normal menstrual cycle.

Animals↗
PubMed1992

A separating method for quantifying mucus glycoprotein localized in the different layer of rat gastric mucosa.

A method was devised for separating rat gastric mucosa into three layers each containing a different mucin species. The mucus gel (first layer) was removed by stirring the gastric mucosa in a solution of phosphate-buffered saline containing 2% N-acetylcysteine. The surface mucosa (second layer), rich in surface mucus cells, was then separated from the deep mucosa (third layer) containing mucus neck cells, by scraping with forceps. The effectiveness of this method was confirmed by light microscopical observation after GOCTS-PCS (dual staining by the galactose oxidase-cold thionin Schiff method and paradoxical concanavalin A method) and AB-PAS staining (dual staining with alcian blue and the periodic acid Schiff method). The fixed specimen of scraped mucus and cell debris was rich in AB-PAS and GOCTS positive mucus, but was hardly stained by PCS, indicating mucus derived from surface mucus cells to have been efficiently recovered from this preparation. The residual mucosa could be stained by PCS but hardly at all by AB-PAS or GOCTS. The lyophilized powder specimens obtained from the three different layers of rat gastric mucosa were used to extract and quantify mucus glycoprotein (mucin). This was done to examine changes in mucin content in the three layers of gastric mucosa one hour following the oral administration of 20% ethanol or 0.35 N hydrochloric acid, both mild irritants. Mucin content was noted to significantly increase in the first layer but hardly at all in the second layer. In the third layer, it decreased significantly by 0.35 N hydrochloric acid, but changed only slightly by 20% ethanol administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1977

Human cervical mucus. III. Isolation and characterization of rheologically active mucin.

Several common mucolytic agents were screened for their ability to solubilize cervical mucus without incurring irreversible losses in mucus viscoelasticity. Sodium thiocyanate was selected on the basis of its effectiveness and handling convenience, and solubilized mucus was fractionated by gel filtration on Sepharose columns. The excluded mucin fraction was characterized by a high neutral hexose to protein ratio and contained all of the elasticity of thiocyanate-treated whole mucus. The concentration of mucin in individual mucus samples collected throughout the ovulatory menstrual cycle was determined from column elution profiles. An increased relative amount of mucin was associated with samples collected during the ovulatory phase of the cycle, and a strong correlation was obtained when the percentage of mucin in individual samples was plotted against their respective storage moduli. These results indicate that the cyclic fluctuations in mucus viscoelasticity seen previously at constant concentrations of nondialyzable solids can be attributed to variations in mucin concentration. Evidence was also obtained, however, for compositional differences in mucus derived from different patients.

Cervix Mucus↗