Gastric juice, ions

Sucralfate (A) contains numerous aluminum hydroxide residues. However, it is not an antacid because it fails to lower the overall acidity of gastric juice. After oral intake, sucralfate molecules undergo cross-linking in gastric juice, forming a paste that adheres to mucosal defects and exposed deeper layers. Here sucralfate intercepts H+. Protected from acid, and also from pepsin, trypsin, and bile acids, the mucosal defect can heal more rapidly. Sucralfate is taken on an empty stomach (1 h before meals and at bedtime). It is well tolerated however, released AP+ions can cause constipation. 

Action on the CNS depends directly on the dose of administered drug, and can be manifested as fatigue, anxiety, tremors, and even convulsions in relatively high doses. Theophylline acts on the cardiovascular system by displaying positive ionotropic and chronotropic effects on the heart, which, can likely be linked to the elevated influx of calcium ions by modulated cyclic adenosine monophosphate and its action on specific cardiac phosphodiesterases. In the gastrointestinal system, methylxanthines simultaneously stimulate secretion of both gastric juice and digestive enzymes. 

Mechanism of Action An Hj-blocker that inhibits histamine action at histaminej receptors of gastric parietal cells. Therapeutic Effect Inhibits gastric acid secretion when fasting, at night, or when stimulated by food, caffeine, or insulin. Reduces volume and hydrogen ion concentration of gastric juice. 

A clinical sample (whole blood, serum, plasma, urine, gastric juice, bile fluid, sweat, etc.) differs from any other analytical sample because of the presence of heterogeneous organic (e.g., proteins) and organic or inorganic components (e.g., urea or sodium ion), sample changes in time (owing to, e.g., denaturation of proteins, escape of C02) and small sample size (even a few tens of microliters). 

Sodium, potassium and chloride are the primary dietary ions that influence the electrolytic balance and acid-base status, and the proper dietary balance of sodium, potassium and chloride is necessary for growth, bone development, eggshell quality and AA utilization. Potassium is the third most abundant mineral in the body after calcium and phosphorus, and is the most abundant mineral in muscle tissue. It is involved in electrolyte balance and neuromuscular function. The content of potassium in poultry diets is usually adequate. Chloride is present in gastric juice and chlorine is part of the HC1 molecule which assists in the breakdown of feed in the proventriculus. Sodium is essential for nerve membrane stimulation and ionic transport across cell membranes. Signs of sodium, potassium or chloride deficiency include reduced appetite, poor growth, dehydration and increased mortality. 

Accumulation of osmotically-active chloride (which is required to maintain electroneutrahty with hydrogen ions) in the canaliculi generates an osmotic gradient that results in outward diffusion of water the resulting gastric juice is about 155 mM HCl and 15 mM KCl, with a small amount of NaCl. The highly acidic enviromnent causes denaturation of proteins, making them susceptible to proteolysis by pepsin (which is itself acid-stable). 

About 70% of the body is composed of water. Fluids such as blood, gastric juices in the stomach, and urine are largely water with dissolved ions such as Na and K. Vitamin A is insoluble in these fluids. There are also fat cells composed of organic compounds having C-C and C-H bonds. Vitamin A is soluble in this organic environment, and thus it is readily stored in these fat cells, particularly in the fiver. 

CHLORIDE An important anion (negative ion) in the maintenance of fluid and electrolyte balance an important component of gastric juice. 

C16. Chosy, J. J., and Schilling, R. F, Intrinsic factor studies. VII. The use of ion exchange diromatography, gel filtration, and ultrafiltration to purify the intrinsic factor of human gastric juice.. Lab. Clin. Med. 61, 907-916 (1963). 

R3. Richmond, V., and Caputto, R., Studies on the large molecular components of gastric juice chromatography on ion-exchange resins. Am. ]. Physiol. 179, 664-665 (1954). Abstr. 

A potassium chloride co-transporter must be closely related to the H /K -ATPase during proton secretion. Potassium and chloride ions move across the apical membrane together with secreted protons Figure 4.1) [15-17]. Potassiiun is recycled while hydrochloric acid of the gastric juice is formed by chloride ions together with the secreted protons. Stimulation of gastric acid secretion across the apical membrane may predominantly reflect the activation or insertion of an active potassium chloride co-transporter rather than direct activation of HVK -ATPase [1]. 

The pH of gastric juice is about 1.5. Assuming that the pH inside the cells of the gastric mucosa is 6.8, calculate the amount of energy required to secrete a mole of H ions. Assume T = 37 C. 

Inorganic nutrients lost in the urine represent nutrients that must be consumed in the diet to maintain nutrient balance. The metal ions that are secreted in gastric juices and intestinal juices are not necessarily lost from the body. They are efficiently reabsorbed by the intestinal tract. Vomiting, however, leads to loss of both gastric and intestinal juices. Diarrhea leads to loss of intestinal juices. 

Ion Intra- cellular Plasma Glo- merular filtrate s Urine Gastric juice Small intestiiul juice Secretory diarthea Sweaf ... 

Gastric juice contains a mixture of water, inorganic ions, hydrochloric acid, pepsinogens, mucus, various polypeptides, and the intrinsic factor. Pepsinogens are precursors of the proteolytic enzymes, pepsins. They are readily converted into the corresponding pepsins by either acid or pepsin itself. Conversion... 

The common ion effect, which is not limited to chloride ions, can result in a reduction of the solubility in gastric juice and may reduce drug absorption. It is possible to determine whether the effect is likely to occur by comparing the intrinsic dissolution rate (IDR) or solubility of the drug in distilled water and in sodium chloride solution, 1.2% w/v. 

One way to temporarily reduce the H" ion concentration in the stomach is to take an antacid. The major function of antacids is to neutralize excess HCl in gastric juice. The table on p. 634 lists the active ingredients of some popular antacids. The reactions by which these antacids neutralize stomach acid are as follows ... 

Dimethyinitrosamine, (CH3)2N20, is a carcinogenic (cancer-causing) substance that may be formed in foods, beverages, or gastric Juices from the reaction of nitrite ion (used as a food preservative) with other substances. 

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