Gastric juice control

Fix, J. A., and Leppert, P. S., Erodible poly(ortho ester) drug delivery systems In vitro erosion in canine and USP-stimulated gastric juice, J. Control. Rel., 4, 87-95, 1986. 

Carbonate anhydrase (carbonic anhydrase, EC 4.2.1.1) catalyzes the reversible interconversion of C02 and HCO3 (see Sect. 3.7.3). The enzyme is found in erythrocytes, and in kidney and gastric juices where it contributes to the control of the acid-base balance. The esterase activity of carbonic anhydrase is probably due to the similarity between its active site and that of the zinc proteases. A possible physiological role of the esterase activity of this enzyme remains to be established. 

The human body has a number of different pH environments. For example, blood plasma has a rigorously controlled pH of 7.4 (see Box 4.9), the gastric juice is usually strongly acidic (pH from about 1 to 7), and urine can vary from about 4.8 to 7.5. It is possible to predict the qualitative effect of pH changes on the distribution of weakly acidic and basic dmgs, especially in relation to gastric absorption and renal excretion ... 

This vitamin is not synthesized in animals, but rather it results from the bacterial or fungal fermentation in the rumen, after which it is absorbed and concentrated during metabolism. Among the known vitamins, this exclusive microbial synthesis is of great interest. One of the major results of vitamin Bn deficiency is pernicious anemia. This disease, however, usually does not result from a dietary deficiency of the vitamin, but rather by an absence of a glycoprotein ( gastric intrinsic factor ) in the gastric juices that facilitates absorption of the vitamin in the intestine. Control of the diseases hence is either by injection of Bn or by oral administration of the intrinsic factor, with or without the vitamin injection. 

The volume of the collected gastric juice is measured. Acid concentration is measured by titration against 100 mm NaOH to an endpoint of pH 7. Total acid output (mmol H+/3 h) is calculated and percent inhibition of the treated rat group is calculated against the control group. Using various doses, dose-response curves can... 

Some time ago we determined total dissolved mucin and its fractions during fasting and after alcohol test meals, histamine injection, and i.v. insulin in gastric juices of 60 patients with peptic ulcer and 106 controls with various gastric disorders (G30), In each of the 841 gastric specimens, the total dissolved mucin and its two fractions (mucoprotein and... 

Fig. 22. Optical density of the diphenylamine reaction in the gastric juice in various gastric diseases and in normal controls.

Ishimori in our laboratory injected Ii -labeled albumin i.v. into more than 20 patients vrith various gastric disease and controls to ascertain the passage of labeled albumin into the gastric juice at various time intervals after injection, extending up to 7 days. Methods used for... 

Another antibody was experimentally produced in rabbits by injecting pepsin (G5). It was detected by the Ouchterlony technique and precipitation reactions, and may have some clinical significance in producing atrophy of chief cells. Repeated injection of this immune serum into rats also caused decrease in the volume of gastric juice, with lower concentrations of acid and pepsin. The controls injected with antibodies to egg albumin, nonspecific globulins, and saline did not show similar changes (see Fig. ). 

All dogs were tested for precipitation reactions with injected gastric juice. Results demonstrated appearance of the precipitant approximately 6 months after the start of injections in only 1 control, but in as many as 14 of 20 sera of dogs injected with gastric juice. Precipitation reactions performed with coated gastric mucosal extracts yielded 14 of 19 positive tests in dogs treated with gastric juice, but in only 1 of 7 controls (H13). 

G74. Gullberg, R., Electrophoretic fractionation of B j-binders in gastric juice from patients with pernicious anemia and from controls. Proc. Soc. Exptl. Biol. Med. 105, 62-66 (1960). 

Zinc acetate (Galzin, Gate Pharmaceutical Co), developed for the treatment of Wilson s disease (4), has been used in maintenance therapy of adult and pediatric disease, but it also has efficacy in the treatment of pregnant women and presymptomatic patients from the start. It also has value as adjunctive therapy for the initial treatment of symptomatic patients. Its mechanism of action involves induction of intestinal cell metaUothionein, which blocks copper absorption from the intestinal tract. Negative copper balance is caused by blockade not only of absorption of food copper but by blockade of reabsorption of the considerable amount of endogenously secreted copper in saliva, gastric juice, and intestinal secretions. It is therefore effective in controlling copper concentrations and toxicity in Wilson s disease. 

If you maintain a tropical-fish aquarium similar to the one shown in Figure 19-22, you know that the pH of the water must be kept relatively constant if the fish are to survive. Control of pH is important in your body, too. The pH of your blood must be maintained at an average of 7.4. A potentially fatal problem will develop if the pH rises or falls as much as 0.3 pH unit. The gastric juices in your stomach must have a pH between 1.6 and 1.8 to promote digestion of certain foods. How does your body maintain pH values within such narrow Umits ft does so by producing buffers. 

---