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Biomedical subjects

R Honda

Publications and source records attributed to R Honda.

At least 145 records · Page 8Linked to original sources
PubMed1978

Control of lower-esophageal-sphincter contractile activity by motilin in conscious dogs.

The effect of synthetic motilin on contractile activity in the lower esophageal sphincter (LES) and the stomach has been studied in 5 healthy dogs by means of chronically implanted strain gage force transducers. Motilin produced strong contractions in the LES and the stomach simultaneously after intravenous doses ranging from 0.3 to 2.7 microgram/kg hr, which were similar to the naturally occurring interdigestive contractions in the LES and the stomach. However, these contractions could be induced only in the interdigestive state; infusion of motilin into dogs in the digestive state brought about no significant effect on either the LES or the stomach. Motilin-induced contractions in the LES and the stomach were instantly abolished by ingestion of food. It is considered that the contractions induced by motilin are identical with the naturally occurring interdigestive contractions in the LES and these contractions are the most orad component of the interdigestive cyclic recurring caudad-moving bands of strong contractions in the dogs.

Animals↗
PubMed1977

An extraluminal force transducer for recording contractile activity of the gastrointestinal smooth muscle in the conscious dogs: its construction and implantation.

An extraluminal strain-gauge force transducer has been developed for recording contractile activity of the gastrointestinal smooth muscle. The details of its construction and implantation were described. The transducer unit allows for continuous long-term recordings (more the 5 months) from conscious experimental animals. It could be constructed in any laboratory and easily implanted in animals if it is done in aseptic technique. Since it is sutured onto the outside of the gut, it does not interfere passage of the contents. The only disadvantages are that it only measures muscle contractions and it is hard to determine movements of intraluminal contents especially in the digestive state.

Animals↗
PubMed1977

[The motility of the lower esophageal sphincter (author's transl)].

Changes in lower esophageal sphincter (LES) motility have been mainly studied by intraluminal manometry. However, it is not suitable for continuous measurement of LES pressure. With extraluminal force transducers developed and constracted in our laboratory, we measured changes in contractile activity of the LES. Three anesthetized mongrel dogs were used for preliminary experiment. A transducer was sutured on the serosal surface of the LES immediately inferior to the phrenoesophageal membrane. A catheter with a side hole was simultaneously passed into the stomach through a mouth so that the side hole was anchored at the highest pressure zone of the gastroesophageal junction. It was found that dose-related changes in motor activity of the LES to pentagastrin were obtained by both methods. This result indicate changes obtained by transducers represent those in intraluminal pressure measured manometory. Transducers were chronically implanted on the LES and the gastric body and antrum to record changes in contractile activity in conscious state. It was found that a group of contractions lasting for 25 +/- 2.5 min occurred at regular intervals of quiescence until next meal. Furthermore, these motor increase precisely coincided with the interdigestive contractions of the stomach.

Animals↗
PubMed1976

Motilin-induced mechanical activity in the canine alimentary tract.

Gastrointestinal contractile activity from the lower esophageal sphincter to the terminal ileum in the conscious dogs was continuously recorded on a multi-channel polygraph for several weeks by means of chronically implanted strain gage force transducers. It was found that the 24-hour gastrointestinal motor activity consisted of the two different major patterns; the digestive and interdigestive patterns. The interdigestive motor activity was characterized by a cyclic recurring, caudad-moving band of strong contractions interrupted by long lasting motor quiescence. When one band of strong contractions reached the distal ileum, another developed in the LES, stomach and duodenum again and propagated in a caudad-direction. Such recycling episodes repeatedly occurred until the next meal. After ingestion of food, gastrointestinal motor activity was continous and such characteristic interdigestive patterns were not observed. Synthetic motilin, 0.1-2.7 mug/kg/hr, was assayed for its motor stimulating activity in the both states. In the digestive state, an i.v. infusion of motlin had no influence upon the motor activity even if the dose was increased up to 6.0 mug/kg/hr. On the other hand, when motilin was infused during the interdigestive state, it induced a pattern precisely like the naturally-occurring interdigestive contractions. Not only the naturally-occurring contractions but also motilin-induced contractions were strongly inhibited by the ingestion of food or an i.v. infusion of pentagastrin (0.2-1.8 mug/kg/hr). Duodenal acidification (0.1 N HC1, 3-16 ml/kg/hr) in the interdigestive state disturbed or inhibited the regular cycle of the natural contractions but was counteracted by exogenous i.v. infusion of motilin. These findings strongly suggest the view that the interdigestive gastrointestinal motor activity is at least in part regulated by circulating motilin concentration in the blood, however, its cyclic recurring, caudad propagating mechanism may be controlled in part by the nervous system. Motilin is the only substance known to be active during the interdigestive state and therefore may be called the interdigestive hormone.

Animals↗
PubMed1975

The negative feedback mechanism of gastric acid secretion: Significance of acid in the gastric juice in man and dog.

As reported previously, gastrin-stimulated gastric secretion in the dog and in man was suppressed by an intravenous infusion of secretin, These results, both in the dog and in man, also were obtained by introduction of acid into the duodenum, which indicated that both endogenous and exogenous secretion inhibit gastrin-stimulated gastric secretion at the oxyntic cell level. Feeding a test meal in man gave rise to an increase of plasma gastrin, reaching a peak of 120 pg. per milliliter at 15 minutes after feeding and remaining above control level for 2 to 3 hours. Is was found that plasma gastrin was suppressed greatly during the intravenous infusion of pure secretin. In animal experiments endogenous gastrin release produced by irrigation of the antral pouch also inhibited both endogenous and exogenous secretin. These results indicate that secretin inhibits gastrin release at the G-cell level in the antrum. On the other hand, it also was observed that endogenous gastrin release ceased when the pH of the perfusate dropped below 2.5. The following conclusions are drawn from the above findings. (1) Gastrin release is suppressed primarily by direct contact of acid with the antrum. The feedback mechanism in this case operates intraluminally in the stomach. (2) The low pH content of the stomach stimulates the release of secretin from the duodenum. The secretin released in this way not only inhibits gastric acid secretion at the oxyntic cell secretin released in this way not only inhibits gastric acid secretion at the oxyntic cell secretin released of gastrin at the G-cell level in the antrum. The level but also blocks the release of gastrin at the G-cell level in the antrum. The feedback mechanism brought about by acid of gastric origin occurs through the general circulation.

Animals↗
PubMedDate not supplied

The renal handling of calcium and phosphorus in environmental cadmium-exposed subjects with renal dysfunction.

Clearance methods were used to clarify the renal handling of calcium (Ca) and phosphorus (P) in a population with renal dysfunction induced by exposure to environmental cadmium (Cd). Seventy-six Cd-exposed subjects (32 men and 44 women) and 36 non-exposed subjects (18 men and 18 women) took part in this study. Fractional excretion of P was higher in the Cd-exposed subjects than in the non-exposed subjects, while that of Ca was equal to that of the non-exposed subjects. The urinary excretion rates of Ca and P tended to be lower in the Cd-exposed subjects than in the non-exposed subjects. The urinary excretion rate of Ca was closely related to creatinine clearance, while that of P was related to creatinine clearance and the percentage tubular reabsorption of phosphorus. It is thought that in Cd-induced renal dysfunction the urinary excretion of Ca depends on glomerular function, and no increased excretion of urinary Ca was observed by these clearance methods. It is also clarified that the parallelism in the urinary excretion of Ca and Na persists in Cd-exposed subjects with renal dysfunction.

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