Mucus alteration

Precellular solute ionization dictates membrane permeability dependence on mucosal pH. Therefore, lumenal or cellular events that affect mucosal microclimate pH may alter the membrane transport of ionizable solutes. The mucosal microclimate pH is defined by a region in the neighborhood of the mucosal membrane in which pH is lower than in the lumenal fluid. This is the result of proton secretion by the enterocytes, for which outward diffusion is slowed by intestinal mucus. (In fact, mucosal secretion of any ion coupled with mucus-restricted diffusion will provide an ionic microclimate.) Important differences in solute transport between experimental systems may be due to differences in intestinal ions and mucus secretion. It might be anticipated that microclimate pH effects would be less pronounced in epithelial cell culture (devoid of goblet cells) transport studies than in whole intestinal tissue. 

Therefore, the unresolved question remains of whether chronic, recurring inflammation is the result of a persistent infection with a specific pathogen, an exaggerated exposure to resident normal luminal bacteria products because of increased intestinal permeability or alteration of mucus composition, or an abnormally aggressive immune response to luminal components. 

Alterations in mucosal defense induced by HP or NSAIDs are the most important cofactors in peptic ulcer formation. Mucosal defense and repair mechanisms include mucus and bicarbonate secretion, intrinsic epithelial cell defense, and mucosal blood flow. Maintenance of mucosal integrity and repair is mediated by endogenous prostaglandin production. 

A particular pulmonary irritant may alter air or mucus flow, and this in turn is one of the factors determining the local tissue dosage of the irritant. Such positive or negative feedback effects should also be incorporated into a dynamic model. 

The efficiency of mucociliary transport depends on the force of kinociUary motion and the viscosity of bronchial mucus. Both factors can be altered pathologically (e.g., in smoker s cough, bronchitis) or can be adversely affected by drugs (atropine, antihistamines). 

The third condition, late respiratory systemic syndrome, is characterized by cough, mucus production, occasional wheezing, and systemic symptoms of malaise, chills, fever, and aching muscles and joints, occurring 4—12 hours alter exposure. This syndrome also has been termed TMA flu and clinically resembles hypersensitivity pneumonitis with visible chest X-ray infiltrates. High levels of IgG serum antibody and total serum antibody directed against trimellityl-human protein conjugates accompany the syndrome, and a latent period of exposure before the onset of symptoms is typical. 

Combination OCs - Combination OCs inhibit ovulation by suppressing the gonadotropins, FSH, and LH. Additionally, alterations in the genital tract, including cervical mucus (which inhibits sperm penetration) and the endometrium (which reduces the likelihood of implantation), may contribute to contraceptive effectiveness. 

These combined contraceptives seem to function by inducing feedback inhibition of gonadotrophin secretion which, in turn, inhibits the process of ovulation (Chapter 8). They also induce alterations in the endometrial tissue that may prevent implantation. Furthermore, the progestogen promotes thickening of the cervical mucus, which renders it less hospitable to sperm cells. This combination of effects is quite effective in preventing pregnancy. 

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