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Biomedical subjects

J E Varhaug

Publications and source records attributed to J E Varhaug.

At least 73 records · Page 4Linked to original sources
PubMed1987

Gastric epithelial restitution at low luminal pH during influence of pentagastrin or cimetidine in the cat.

This study examines restitution of the gastric surface epithelium at luminal pH 1 after damage to the gastric mucosa by instillation of 2 M NaCl for 10 min. After mucosal damage, potential difference decreased to zero and H+ back-diffusion increased. Gastric blood flow increased after exposure to 2 M NaCl, irrespective of the secretory state of mucosa. Neither pentagastrin nor cimetidine showed any protective effect against mucosal damage produced by 2 M NaCl. Ninety minutes after mucosal exposure to 2 M NaCl there was an almost complete restitution of the gastric surface epithelium in pentagastrin-stimulated and cimetidine-treated animals, whereas about 15% of the gastric surface still showed damage in animals in which acid secretion was not interfered with. These findings show that restitution of the surface epithelium, in vivo, is a rapid and resistant process even at a very low luminal pH. The secretory state of mucosa may have some influence on this process.

Animals↗
PubMed1987

Regional blood flow and acid secretion associated with damage and restitution of the gastric surface epithelium in cats.

The gastric mucosa of anesthetized cats was exposed to 2 M NaCl for 10 min. After returning to gastric perfusion with 150 mM NaCl and pH 7.40, with and without pentagastrin stimulation, transmucosal potential difference decreased to zero and then gradually increased to approximately half the original value during the following 90 min. H+ secretion decreased and remained close to zero after exposure to 2 M NaCl in nonstimulated cats, whereas pentagastrin-stimulated secretion gradually increased to nearly half the preexposure level. Mucosal blood flow increased, and the vascular resistance decreased in the posterior wall of the stomach corresponding to epithelial damage, as observed by light microscopy after 15 min. Blood flow during pentagastrin stimulation was initially high in fundus and corpus and did not increase further after exposure to 2 M NaCl, but showed similar changes as without pentagastrin in the antrum. Epithelial restitution occurred within 90 min during both nonstimulated conditions and pentagastrin stimulation. In control animals subjected to 150 mM NaCl there were no changes in transmucosal potential difference, H+ secretion, or blood flow throughout the experiment and epithelial damage was not found. In conclusion, damage caused by 2 M NaCl to the gastric surface epithelium was associated with decreased acid secretion and increased mucosal blood flow. These factors may contribute to creating favorable conditions for the epithelial restitution, indicated by restoration of transmucosal potential difference and observed by light microscopy.

Animals↗
PubMed1984

Gastric blood flow determination: intramural distribution and arteriovenous shunting of microspheres.

Total and regional gastric blood flows were measured in 23 anesthetized cats by labeled 10-micron (range 8-12 microns) and 15-micron (range 12-20 microns) microspheres. Total blood flow correlated closely with the gastric venous outflow. Flow estimates by 10-microns spheres were 2.95% lower than simultaneous 15-micron estimates. Approximately 2% of the 10-micron spheres and 0.1% of the 15-micron spheres were shunted through the gastric vasculature. The diameter distribution of 6,245 embolized spheres, measured by microscopy, corresponded to that of the injectate, except for a lack of the smallest spheres. Within the mucosa, the 10-microns spheres predominantly lodged in the glandular layer, whereas larger spheres gradually lodged more basally; 50% of the 15-microns population appeared in the lamina propria below the gland bases. Vasodilation did not alter the intramucosal distribution. Spheres in the subglandular lamina propria represented blood flow mainly to the glandular layer. It is therefore essential for reliable estimation of blood flow to the glandular layer of the mucosa that the lamina propria is completely included in the specimens. The submucosa contained only 0.5% of the 10-microns and 2.2% of the 15-micron embolized spheres. Spheres of 10.5-17 microns in diameter are considered the most suitable for determination of gastric blood flow.

Animals↗
PubMed1983

Regional gastric blood flow and acid secretion during histamine H2 receptor blockade in cats.

Experiments were performed in anesthetized cats. Tissue blood flow and cardiac output were measured by means of labeled microspheres. Cimetidine did not affect gastric blood flow at basal conditions. Pentagastrin stimulation more than doubled corpus-fundus mucosal blood flow (MBF). Cimetidine reduced pentagastrin-stimulated corpus-fundus MBF and acid output towards basal level. Recovery of acid secretion after inhibition by a bolus dose of cimetidine occurred without a corresponding restoration of MBF. Neither pentagastrin nor cimetidine significantly altered antrum MBF or muscularis blood flow. The study demonstrates that cimetidine reduces the ratio between pentagastrin-stimulated acid secretion and corpus-fundus MBF by lowering secretion considerably more than the corresponding MBF.

Animals↗
PubMed1982

Immunological characterization of mononuclear cells in thyroid gland and blood in Graves' disease, multinodular goiter and papillary carcinoma.

Mononuclear cell infiltrates in thyroid gland tissue sections from patients with drug-treated Graves' disease (n = 5), non-toxic nodular goiter (n = 12) and papillary carcinoma (n = 5) were characterized by immunological membrane receptors. T lymphocytes were identified using 2-aminoethylisothiouronium bromide hydrobromide (AET)-treated sheep erythrocytes (E) (E-AET). E sensitized with rabbit IgM antibodies (A) and human complement (C) (EAC) were used to detect receptors for C3b (B lymphocytes and monocytes) or C3d (B lymphocytes). E sensitized with rabbit IgG antibodies were used to detect receptors for the Fc portion of IgG (FcR; lymphocytes and monocytes). The results indicate that T and B lymphocytes infiltrate the thyroid gland in Graves' disease as well as in nodular goiter. T lymphocytes seemed to predominate in both disorders. In thyroid papillary carcinoma the number of B and T lymphocytes was negligible. However, EA absorbed strongly to sections from 3 of the 5 tumors studied, indicating the presence of FcR on tumor cells or infiltrating host cells. The percentage of active and total T lymphocytes in peripheral blood from the patients with drug-treated Graves' disease was markedly reduced (9 +/- 5 and 28 +/- 11%, controls 22 +/- 9 and 68 +/- 11%; p less than 0.01 and less than 0.001). In patients with nodular goiter the percentage of total T lymphocytes was slightly, but significantly decreased (p less than 0.05). We suggest that the marked decrease in blood T lymphocytes observed in Graves' disease might be caused by the drug therapy. In nodular goiter the predominance of T lymphocyte infiltration together with a slight decrease in blood T lymphocytes suggest that autoimmune mechanisms are involved in the pathogenesis.

Adult↗
PubMed1981

Effects of hemorrhagic shock on gastric blood flow and acid secretion in cats.

Anesthetized cats were cannulated and successively bled to arterial pressures of 100, 75 and 50 mmHg. The pressure was maintained at each level for 20 min. One group of animals was given 16 mu . kg-1 . h-1 of pentagastrin and another group 2 mg . kg-1 . h-1 of cimetidine throughout the experiment. Blood flow was determined by means of the microsphere distribution technique using spheres 14 +/- 1 micrometer in diameter. At each pressure level 15 min sample of gastric juice were collected. Twenty ml of saline was instilled into the stomach and withdrawn together with the gastric juice. Adenosine triphosphate (ATP) content and enzymatic activity (LD, ASAT) of the gastric mucosa and blood pH, pCO2 were determined at 140 and at 50 mmHg. In both pentagastrin and cimetidine treated cats gastric mucosal blood flow decreased and the vascular resistance increased markedly when the pressure was lowered by bleeding from 140 to 100 mmHg. On further bleeding to 50 mmHg only slight additional flow reduction occurred and the vascular resistance remained constant. Under shock blood flow was higher and the resistance lower in pentagastrin than in cimetidine treated animals. In pentagastrin treated animals a parallel decrease in acid secretion and mucosal blood flow occurred under shock. Cimetidine inhibited acid secretion both at normal blood pressure and under shock. The ATP content of the mucosa did not decrease, no morphological changes of the mucosa occurred and there was no leakage of cellular enzymes during the period of hypotension.

Adenosine Triphosphate↗
PubMed1980

Changes in gastric mucosal morphology, capillary permeability and blood flow during the first 3 days of acute gastritis in cats.

In the present investigation gastric morphology, blood flow, vascular permeability and water content were studied in cat stomachs with acetic acid-induced gastritis at different time intervals up to 3 days after induction of gastritis. The morphological changes including mucosal erosions, edema and hemorrhage showed normalization within 3 days. The mucosa and muscularis blood flow remained essentially unchanged compared with pre-gastritis values and with the control group. Gastritis was associated with leakage of circulating albumin into the stomach wall most pronounced 4 h after the induction of gastritis. The water content was high at 4 and 24 h after induction of gastritis with almost normalization at 3 days. The morphologaical characteristics of our model are very similar to those observed in man. Leakage of circulating albumin into the gastric wall seems to be the best parameter for quantifaication of the inflammatory changes found in acute gastritis, while blood flow seems to be a less important parameter.

Acute Disease↗
PubMed1980

The effect of intragastric pressure on gastric blood flow after partial devascularization of the stomach in cats.

The influence of intragastric pressure (IGP) on gastric blood flow was studied in cats with regional ischemia due to partial gastric devascularization, and in sham-operated cats. IGP was controlled by intragastric installation of saline. Blood flow was determined by means of the microsphere distribution technique. Increment of IGP reduced mucosal and muscularis blood flow in all areas of the stomach, both in sham-operated and devascularized cats. In areas with reduced mucosal blood flow due to devascularization, blood flow became further reduced by IGP to an extremely low flow level. The present results are pertinent to the pathogenesis of early lesser curvature ulcer or necrosis sometimes ll areas of the stomach, both in sham-operated and devascularized cats. In areas with reduced mucosal blood flow due to devascularization, blood flow became further reduced by IGP to an extremely low flow level. The present results are pertinent to the pathogenesis of early lesser curvature ulcer or necrosis sometimes ll areas of the stomach, both in sham-operated and devascularized cats. In areas with reduced mucosal blood flow due to devascularization, blood flow became further reduced by IGP to an extremely low flow level. The present results are pertinent to the pathogenesis of early lesser curvature ulcer or necrosis sometimes occurring after proximal gastric vagotomy in man.

Animals↗
PubMed1979

Effect of partial gastric devascularization on mucosal blood flow and acid secretion in cats.

Partial devascularization of the stomach was performed in cats anesthetized with pentobarbital. The devascularization included all blood vessels along the greater curvature and two of the main branches of the left gastric artery. Gastric mucosal blood flow and cardiac output were determined by means of the microsphere distribution technique. The acid (H+) output from the 30th to the 60th min of pentagastrin stimulation was used as the 'acid response value'. Blood flow and acid secretion were determined before and approximately 2 h after devascularization or sham operation. A marked decrease in acid secretion and mucosal blood flow of the corpus/fundus occurred after devascularization. A high degree of correlation was found between the decrease in acid secretion and the decrease in mucosal blood flow caused by the devascularization. The regression coefficient of acid secretion on mucosal blood flow did not change significantly after devascularization.

Animals↗
PubMed1979

Reduced mucosal blood flow and acid secretion related to accelerated healing of gastric ulcer in rats after omentectomy including partial gastric devascularization.

Gastric ulcers were produced in rats by local application of acetic acid to the serosal surface of the stomach. In half of the animals the greater omentum was excised just before the application of acid. Gastric mucosal blood flow was estimated by means of the (14C)-aniline clearance technique. Gastric acid secretion was determined under basal conditions and under pentagastrin stimulation. Removal of the greater omentum resulted in accelerated healing of the gastric ulcers. Maximal acid output and mucosal blood flow were found to be decreased in omentectomized animals 24 h after ulcer induction. 3 weeks later the secretion and blood flow in omentectomized animals did not differ significantly from the values of the control animals. The accelerated ulcer healing in omentectomized animals is assumed to be due to decreased acid secretion resulting from decreased mucosal blood flow following partial devascularization of the stomach.

Animals↗