Orogastric Administration Research Articles

Estimation of glomerular filtration rate in conscious dogs following a bolus of creatinine

The renal clearance of creatinine was measured following orogastric administration in conscious dogs. Values of creatinine clearance were compared with simultaneously determined values of inulin clearance, when urine volume, glomerular filtration rate and volume status were acutely altered by a variety of experimental manoeuvres. At urine volumes greater than 20 microliters X min-1 X kg-1, creatinine clearance was not significantly different from inulin clearance. At low urine volumes there was some evidence of creatinine reabsorption. It is concluded that the bolus creatinine technique provides reliable estimates of glomerular filtration rate and is particularly applicable to long-term studies in conscious dogs.

Renal handling of potassium in dogs with chronic renal insufficiency

The dynamics of potassium excretion were examined in normal dogs and dogs with chronic renal insufficiency of at least 4 weeks' duration (remnant model). All animals, in balance on diets providing 15, 50, or 100 mEq of potassium and 100 mEq of sodium, were challenged with 50 mEq of potassium chloride. Immediately thereafter, hourly clearances were obtained for 5 hours. Irrespective of dietary potassium, mean fasting serum potassium and urinary potassium excretion (UKV) were similar in normal and remnant dogs with mean GFR's of 57 +/- 3 and 16 +/- 3 ml/min, respectively. After orogastric administration of 50 mEq potassium, serum potassium rose significantly more in remnant (2.2 to 2.5 mEq/liter) than in normal (0.9 to 1.2 mEq/liter) groups (P less than 0.001). Conversely, UKV increased significantly less, 70 to 96 vs. 151 to 194 micro Eq/min, respectively (P less than 0.001). In 5 hours, normal animals excreted 61 to 67% of the load, but remnant dogs only 30 to 37% (P less than 0.001). In all groups, UKV correlated directly with serum potassium concentration. But this relationship was markedly attenuated in the remnant groups (P less than 0.001) and independent of dietary potassium. In contrast, the same slope describes the relationship between UKV/GRF and serum potassium for all, normal and remnant, animals. The blunted kaliuresis occurred despite the more severe hyperkalemia in remnant than in normal dogs; it was not associated with significant changes in acid-base, diuresis, natriuresis, serum glucose, insulin, and glucagon concentrations and occurred despite prolonged hyperaldosteronism. The results demonstrate a severe limitation of the remnant kidney's ability to rapidly excrete a potassium load. Changes in serum potassium, or a consequence thereof, are important for the urinary excretion of potassium following its acute administration.

Etiology of tetracycline-associated pseudomembranous colitis in hamsters.

Tetracyclines were implicated in the 1950s in induction of protracted diarrhea and pseudomembranous colitis. Because the pathogenetic mechanism of these illnesses has been questioned recently, we studied tetracycline in hamster models of antibiotic-associated colitis. Orogastric administration of tetracycline caused diarrhea and death, with evidence of hemorrhagic typhlitis. Filtrates of cecal contents were toxic when inoculated into normal hamsters and cell culture monolayers, and toxicity was neutralized with Clostridium sordellii antitoxin. Tetracycline-resistant C. difficile was cultured from stools of these hamsters, but Staphylococcus aureus was not isolated. The value of tetracycline for treatment or prevention of clindamycin-induced colitis in hamsters was also studied, and it was found that daily orogastric administration of tetracycline was poorly protective against clindamycin-induced colitis.

Progestagens in Mares' Milk

The presence of hormones and hormone-like substances in milk was described more than 50 years ago, with further important studies being performed in the late 1950s and early 1960s. Although many methodological problems still remain unsolved, progress in this area has been possible because of the development of new methods for hormone determination. Because milk is heterogenous, different substances can interfere with various determinations; thus, many of the results, especially quantitatively, are affected. This chapter focuses on several aspects of hormones in milk. Specifically, it discusses (1) their presence in various species, (2) factors influencing their presence and concentration in milk, (3) their effect on the gastrointestinal tract after orogastric administration in developing mammals, (4) the absorption of those hormones present in milk from the gastrointestinal (GI) tract of immature mammals, and (5) the known low proteolytic activity of the GI tract of the newborn. Higher permeability for the macromolecules enhances the possibility of biological activity of various milk-borne hormones, including those of peptide character.

Site and characteristics of electrolyte loss and effect of intraluminal glucose in experimental canine cholera.

The site and characteristics of gastrointestinal electrolyte loss were investigated in eight dogs with experimental cholera induced by orogastric administration of 6-hr broth cultures of Vibrio cholerae, strain Ogawa 395. In these animals, all electrolyte losses originated in the small bowel, predominantly from the jejunum and ileum. The bicarbonate concentration of the small bowel fluid showed a progressive increase from duodenum, where it was less than that of plasma, to the terminal ileum, where it was significantly greater than that of simultaneously obtained plasma. Studies of the responses of chronic Thiry-Vella jejunal loops (five dogs) and chronic Thiry-Vella ileal loops (five dogs) to intraluminal challenge by cholera exotoxin demonstrated that all loops exhibited isotonic electrolyte loss for a 14-18 hr period after challenge. The bicarbonate concentration of fluid produced by exotoxin-challenged jejunal loops was not significantly different from that of plasma, whereas the ileal loops produced fluid with a bicarbonate concentration approximately three times that of plasma. The effect of intraluminal glucose on the response of canine gut to cholera exotoxin was investigated by perfusion studies in 12 dogs with chronic Thiry-Vella fistulae. Intraluminal glucose significantly enhanced isotonic fluid absorption in both jejunal and ileal loops. The net effects of glucose on isotonic fluid absorption were equal before and after intraluminal administration of crude cholera exotoxin. These data suggest that cholera exotoxin causes gut electrolyte loss by a mechanism independent of that by which glucose enhances sodium absorption.

Toxicity of the Mucigogue, Eugenol, Administered By Stomach Tube to Dogs

Summary A toxicity study is reported in which dogs were given intragastric instillations of eugenol emulsions, in order to determine the toxic reactions to this compound and the order of magnitude of safe dosage. In general, body temperature was slightly depressed, pulse rate increased, and respiratory rate was unaffected. Vomiting occurred only occasionally at a dosage level of about 2.5 gm./10 kg. body weight, but at the highest dosage employed (approximately 5 gm./10 kg.), its incidence was 65%. Marked motor dysfunction, primarily of the hind limbs, was observed only at this maximum dosage in half of the experiments. Death occurred only after the highest dosage of eugenol in 2 of the 4 dogs used for the 6 experiments at this level. Thus, it would appear that a dosage of about 0.2 gm./kg. (100 ml. of 2% emulsion) is safe for experiments in dogs requiring orogastric administration of eugenol emulsion. Repeated administration at this dosage level (10 doses over a 3-week period) gave no indication of a cumulative effect.