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Biomedical subjects

A Miyoshi

Publications and source records attributed to A Miyoshi.

At least 109 records · Page 6Linked to original sources
PubMed1982

Cysteamine-induced inhibition of acid neutralization and the increase in hydrogen ion back-diffusion in duodenal mucosa.

To investigate the possible impairment of defensive mechanisms in cysteamine-induced duodenal ulceration, the effect of cysteamine on the neutralization of acid by the duodenum and the back-diffusion of hydrogen ions into the duodenal mucosa has been studied. The results obtained were as follows. (1) The intraduodenal pH started to decrease between 3 and 4 hr after cysteamine injection. (2) By perfusion of the duodenal loop excluding the opening of bile and pancreatic ducts, the amount of hydrogen ions (H+) neutralized was found to be significantly lower in cysteamine-treated animals than in the controls. (3) the back-diffusion of luminal H+ into the duodenal mucosa, estimated by measuring the H+ disappearance from the test solution including 100 mM HCl, was significantly increased by cysteamine. From these findings, it has been concluded that cysteamine reduces the resistance of duodenal mucosa to acid coming from the stomach.

Animals↗
PubMed1982

Electrophysiological effects of disopyramide phosphate in patients with sinus node dysfunction.

The electrophysiological effects of intravenous administration of disopyramide (1.5 mg/kg) were studied in 26 patients with sinus node dysfunction (SND). Disopyramide shortened spontaneous cycle length (SCL) in 12 patients and lengthened it in 4. Maximum sinus node recovery time (max SRT) was prolonged in 9 patients and shortened in 6. Estimated sinoatrial conduction time (SACT) was prolonged in 4 and shortened in 4 out of 10 patients in whom this measurement was possible. However, these changes were not statistically significant. Neither were there any significant changes in PA and AH intervals nor refractory periods of the AV node. HV intervals and refractory periods of the atrium at matched cycle length were significantly lengthened. Atrial echo beats and atrial premature beats disappeared in 7 of 12 patients treated with disopyramide. In all of these 7 patients atrial refractory period were increased. Thus, the disappearance of atrial echo beats and atrial premature beats was thought to be due to a prolonged atrial refractoriness. In 4 patients who had supraventricular arrhythmias without having either marked prolongation of max SRT or episodes of syncope, disopyramide was administered orally for a long term, during which these arrhythmias and symptoms disappeared and sinus rate increased. These results suggest that disopyramide is useful in patients with SND and supraventricular arrhythmias.

Arrhythmias, Cardiac↗
PubMed1981

Cyclic nucleotide response to acid-secreting stimuli in guinea pig gastric mucosa in vitro.

To investigate the mechanism of intracellular transmission of three representative stimuli for gastric acid secretion, the dose-response relations of cyclic nucleotides accompanied by acid secretion stimulated by histamine, pentagastrin and bethanechol were comparatively studied using an in vitro preparation of guinea pig gastric mucosa surviving with a constant potential difference and acid secretion sensitive to amytal. The following results were obtained. (1) Both histamine- and pentagastrin-stimulated acid secretion accompanied a significant increase in cyclic AMP contents in the gastric mucosa and in the serosal solution without any increase in cyclic GMP. However, the ratio of the increase in acid secretion to that in cAMP content was significantly greater with pentagastrin than with histamine, indicating that pentagastrin exerts its acid-secreting stimulus with less increase in cyclic AMP. (2) Stimulation with bethanechol resulted in a significant increase in the mucosal cyclic GMP content without any change in cyclic AMP. From these findings, it has been concluded that the above three stimuli were transmitted differently in the target cells, presenting evidence against the common final mediator theory of histamine for gastric acid secretion.

Animals↗
PubMed1981

Serum lipids and lipoproteins in patients with gallstone (relationship between serum lipids and types of stones in roentgenograms and sectional views).

Serum lipids and lipoproteins of gallstone patients were analyzed and compared with lithogenesity of bile and type of stones by roentgenographic and cross-sectional views. Incidences of hypercholesterolemia and triglyceridemia were higher in patients with radiolucent gallstones than with radiopaque stones. Furthermore, an incidence of hypertriglyceridemia was higher in patients with radiolucent solitary stones than with radiolucent multiple stones. The degrees of hyperlipidemia were moderate. Lipoprotein disc electrophoresis of sera of hyperlipidemic patients revealed type IIa, IIb or IV. More solitary and less multiple stones were seen in the hyperlipoproteinemic patients than normolipoproteinemic. Multiple stones with normolipoproteinemia were more accompanied by unsaturated bile (lithogenic index less than 1.0) than those with hyperlipoproteinemia and solitary stones with hyperlipoproteinemia or without. Solitary stones obtained surgically from normolipoproteinemic patients were pure cholesterol, combination or mixed stones, while multiple stones not including pure cholesterol and combination stones with pure cholesterol in the center. Solitary stones in hyperlipoproteinemic patients proved mostly either pure cholesterol or combination stones with pure cholesterol ins the center, while multiple stones containing all types of stones inclusive of a small number of other miscellaneous stones except cholesterol stones. Collectively more mixed and other miscellaneous stones except cholesterol stones, and less pure cholesterol and combination stones with pure cholesterol in the center were shown in normolipidemic patients, and vice versa in hyperlipoproteinemic patients. These results suggested serum lipids and lipoproteins being closely related to the initial precipitation, aggregation of cholesterol crystals and development of cholesterol gallstones through lipid metabolism of the whole body.

Adolescent↗
PubMed1981

The increase in putrescine content in the gastric mucosa of rats with ulcerations induced by restraint-immersion stress.

By means of high-performance liquid-chromatography, the putrescine, spermidine and histamine contents in the gastric mucosa were examined during the course of ulceration in rats by the restraint-immersion stress. (1) The putrescine content increased progressively during the course of ulceration with the continuing stress whereas after being released from the stress the content decreased gradually to a significantly lower level than that immediately after 12 hours of the stress. (2) The spermidine content in the gastric mucosa was unchanged during the course of ulceration with continuing stress nor after being released from the stress. (3) The mucosal histamine content decreased significantly after 4 hours under the continuing stress. (3) Extensive histological examination revealed the appearance of regenerating epithelium 36 hours after being released from the stress whereas no such finding was seen before that period. From the above findings, it has been speculated that the increase in the gastric mucosal putrescine content during the course of ulceration induced by restraint-immersion stress is probably due to the stimulated adrenal function by the stress, independently of the regeneration of gastric mucosa.

Animals↗
PubMed1981

Antral gastrin and somatostatin concentrations in peptic ulcer patients.

As an attempt to approach the pathogenesis of peptic ulcer disease, antral gastrin and somatostatin concentrations were studied in normal subjects, patients with duodenal ulcer and gastric ulcer. In the patients with peptic ulcer, antral somatostatin concentrations were significantly lower than those in normal subjects. In non-ulcer subjects, including normal subjects and patients with atrophic gastritis, antral somatostatin concentrations were correlated inversely with the degree of antral gastritis, while in the patients with peptic ulcer, especially in duodenal ulcer, they were low, irrespective of histological picture of antral mucosa. In the patients with duodenal ulcer, low antral somatostatin concentrations with high antral gastrin/somatostatin ratio may cause increased serum gastrin levels and increased gastric acid secretion. From the above findings, it has been concluded that low antral somatostatin levels may be related to the pathogenesis of duodenal ulcer disease.

Adult↗
PubMed1981

Molecular sieve in rat tubular basement membrane as revealed by negative staining.

Rat tubuli were isolated both by the method of Krisko and by a modified method of Cook and Pickering; renal tubular basement membrane (TBM) was isolated by sonic disruption and by the method of Carlson. Using electron microscopy after negative staining, TBM of rat kidney isolated under these different conditions was shown to be a fine meshwork. Strands of the meshwork were interwoven, apparently enclosing pores to make up whole basement membrane. These findings are compared with our previous observation that glomerular and alveolar basement membranes were made up of a similarly fine meshwork.

Albumins↗