Search PubMed⌕ Search

Biomedical subjects

M Miyata

Publications and source records attributed to M Miyata.

At least 595 records · Page 33Linked to original sources
PubMed1980

An appraisal of radical pancreatoduodenectomy based on glucagon secretion.

In an attempt to elucidate changes in endocrine functions of the pancreas associated with radical pancreatectomy for periampullary cancer, plasma levels of insulin (IRI) and pancreatic glucagon (IRG) were measured during arginine infusion in ten patients with periampullary cancer both before and after pancreatoduodenectomy. The response of plasma IRI to arginine which was impaired before the surgery showed further impairment after the surgery. This finding is consistent with the previous results obtained in such patients by oral glucose tolerance testing. Also, the response of plasma IRG was subnormal preoperatively and was found to be impaired postoperatively. Both maximum and integrated secretion of IRG during arginine infusion decreased after the surgery in all instances. From these findings, it is concluded that pancreatoduodenectomy aggravates the already disordered pancreatic endocrine functions, as indicated by arginine infusion in patients with periampullary cancer.

Adult↗
PubMed1980

A simple method for orthotopic liver transplantation in the rat. Cuff technique for three vascular anastomoses.

A simple method for orthotopic liver transplantation in the rat is described in detail. A cuff technique was applied to all anastomoses of the supra- and infrahepatic venae cavae and the portal vein. It simplified and shortened the implantation of the graft as well as eliminating the need for microvascular suture technique. In the last series of 20 transplants, the survival rate was 85% after 1 week and 55% after 2 months with normal hepatocellular function.

Animals↗
PubMed1980

Release of vasoactive intestinal peptide by distention of the proximal stomach in dogs.

The effect of transient proximal gastric distention was studied in six conscious dogs previously submitted to antrectomy and Billroth I anastomosis (and in which the intragastric pH was not altered), and in five anaesthetised dogs prepared with an innervated acute fundic pouch in which the pouch lumen was acidified with 0.15 M hydrochloric acid. Levels of vasoactive intestinal peptide (VIP) in portal and peripheral plasma were measured by radioimmunoassay. In conscious antrectomised dogs, distention of the proximal stomach to volumes of 250 and 500 ml evoked a significant rise of portal VIP concentration, with a maximal variation of 32.7 +/- 4.4 to 67.7 +/- 14.8 pg ml-1, which was hardly reflected in systemic blood. In the anaesthetised dogs, transient distention of the acute fundic pouch with 0.15 M hydrochloric acid under a pressure of 40 cm of water elicited a significant rise of portal VIP from 36.2 +/- 8.9 to 59.8 +/- 12.4 pg ml-1 (P < 0.05) without any significant variation of the peptide concentration in peripheral plasma. These results indicate that vasoactive intestinal peptide is released under transient proximal gastric distention in dogs, and that this response is not solely dependent upon the acid secretory effect of distention in this species.

Animals↗
PubMed1980

Immunoreactive somatostatin and vasoactive intestinal peptide in the digestive tract of cats.

Somatostatin and vasoactive intestinal peptide were measured by radioimmunoassay in acetic acid extracts of tissue samples from the digestive tracts of seven adult cats. The concentration of immunoreactive somatostatin in antral mucosa (2926 +/- 978 pmol/g wet weight, mean +/- SE) was far above the concentrations in the head of the pancreas (442 +/- 94), distal duodenum (377 +/- 91), and ileum (355 +/- 48). Large amounts of immunoreactive vasoactive intestinal peptide were recovered from both mucosal and muscular layers of gastrointestinal tract; the highest values were observed in the muscular layer of the cecum (579 +/- 82 pmol/g) and the mucosa of the right colon (564 +/- 244). The mucosal/muscular layer ratio of vasoactive intestinal peptide concentrations increased caudally from 0.20 in the esophagus to over 1 in the ileum and colon. Upon gel filtration on G-50 Sephadex, somatostatin in the antrum, duodenum, and pancreas were eluted as a predominant peak in the volume of the tetradecapeptide, but somatostatin from the ileum and cecum was associated with a major faster component. Vasoactive intestinal peptide in the muscular layer of gastrointestinal tract and in mucosa of antrum and duodenum consisted essentially of a single form, which coeluted with the purified porcine peptide; a slower component was detected in the mucosa of the ileum and cecum. These reults indicate molecular heterogeneity of both immunoreactive somatostatin amd vasoactive intestinal peptide in the digestive tract of cats, and suggest that the variable ratio of the different molecular forms of each peptide along the gastrointestinal tract may reflect regional specificity of biologic effects and metabolism.

Animals↗
PubMed1980

Effects of test meal, intragastric nutrients, and intraduodenal bile on plasma concentrations of immunoreactive somatostatin and vasoactive intestinal peptide in dogs.

Specific radioimmunoassay were used to measure somatostatin and vasoactive peptide in portal and peripheral plasma from conscious dogs prepared with indwelling portal catheters. In six animals with intact stomachs, a test meal induced a significant rise of portal and peripheral somatostatin, while the significant response of vasoactive intestinal peptide in portal plasma was not reflected in peripheral blood. Similar somatostatin and vasoactive intestinal peptide responses were observed in six dogs previously submitted to antrectomy and Billroth I anastomosis, when given the same test meal, while the gastrin response was 20% of the response in the intact dogs (P < 0.01). The effects of intragastric instillation of 300 ml dextrose, casein hydrolysate, and Intralipid, adjusted to 300 mosmol/kg and pH 7.0, were studied in six dogs with intact stomachs. Casein and Intralipid induced significant increases of somatostatin in portal and peripheral plasma, while VIP increased after Intralipid only, both in portal and peripheral blood. Dextrose resulted in no significant variation of either peptide in portal or in systemic plasma. Intraduodenal infusion of isotonic bile induced a significant release of somatostatin, both in portal and peripheral plasma, but no significant vasoactive intestinal peptide response. These results indicate that several factors can evoke a significant release of somatostatin in dogs, and that the variations of the peptide concentration in portal plasma are reflected in peripheral blood. Among the factors tested, only intragastric fat evoked a vasoactive intestinal peptide response that could be measured in peripheral blood.

Animals↗
PubMed1980

[Deuterium oxide (D2O)--a protective factor for cellular stabilization in hypothermic preservation of the liver? (author's transl)].

Rat livers were preserved by ischemic hypothermic storage in extra- or intracellular type solutions for 24 h. A substitution of 85% of the tissue water by deuterium oxide (D2O) resulted in increased glycolytic energy production, better maintenance of the energy potential of the cells but a higher AMP loss, and a reduction of edema formation. Preservation using "retrograde oxygen persufflation" (ROP) resulted in optimal maintenance of the metabolic state which could be further influenced positively by D2O in the total nucleotide content.

Animals↗
PubMed1980

Hormonal (gastrin, secretin, cholecystokinin) and secretory effects of bombesin and duodenal acidification in dogs.

We have studied the influences of duodenal acidification on the effects of bombesin on gastric and pancreatic secretion and on blood levels of gastrin, secretin, and cholecystokinin (CCK) in six conscious dogs with chronic gastric and pancreatic fistulas. Duodenal acidification suppressed bombesin-stimulated gastric acid output (from 20.1 +/- 4.2 to 8.2 +/- 1.9 mEq/120 min) and gastrin release (from an integrated 2-hour output of 16.0 +/- 1.2 to 11.1 +/- 1.1 ng-min/ml). On the other hand, duodenal acidification augmented bombesin-stimulated secretion of pancreatic bicarbonate (from 0.75 +/- 0.12 to 7.81 +/- 2.0 mEq/120 min) and protein (from 0.57 +/- 0.10 to 1.00 +/- 0.18 gm/120 min). Blood levels of CCK (but not of secretin) were increased with bombesin alone, whereas blood levels of secretin (but not CCK) were increased by duodenal acidification alone. Bombesin plus duodenal acidification resulted in increase of both CCK and secretin. This increase of secretin may be responsible, in part, for suppression of both gastric acid output and gastrin release, as well as for increases in pancreatic secretion of bicarbonate and protein.

Animals↗
PubMed1979

Retroperitoneal hemangiopericytoma associated with hypoglycemia: report of a case.

A 34-year-old woman had episodes of hypoglycemic attack 8 years after a surgical resection of a retroperitoneal hemangiopericytoma. In spite of normal levels of serum IRI, insulin radioreceptor assay demonstrated high level of plasma ILA (insulin like activity). The patient underwent resection of a recurrent retroperitoneal tumor with metastatic lesions of the liver. Postoperatively, ILA level in plasma by insulin radioreceptor assay decreased, and hypoglycemic attacks disappeared. Therefore, this associated hypoglycemia was presumed to be not caused by excess glucose consumption by the tumor, not by excess secretion of IRI by the tumor, but caused by the presence of high level of ILA related to the tumor.

Adult↗
PubMed1979

Change in oscillatory potential by thioridazine.

Toxic effects on the retina by oral administration of thioridazine was investigated by electroretinography (ERG) using male Wistar rats. An obvious reduction followed by a disappearance in the O2 component of the oscillatory potentials of the ERG was seen in a dose-dependent manner. The minimum dosage given to produce the above change was 3 mg/kg/day for 7 days' administration. This change seemed to be permanent, whereas a and b waves as well as other oscillatory potentials, e.g., O1, O3, were normal throughout the experiment. The significance of the data is discussed.

Action Potentials↗
PubMed1979

[Hypothermic storage under aerobic conditions--the effect of different flushing solutions on kidney functional recovery].

Canine kidneys (n = 17) were flushed with COLLINS (C2), SACKS II, LAMBOTTE (KMgS), ROSS (hypertonic citrate), or RINGER glucose-mannitol solution following a 30-min period of normothermic ischemia. After 24 h hypothermic preservation with retrograde oxygen persufflation (ROP) and autotransplantation, the immediate functional recovery was determined using inulin and PAH clearance methods and compared with the normal contralateral kidney. While a good functional recovery was found in the COLLINS group, significantly exceeding results from hypothermic ischemic storage preservation, in experiments using other flush solutions ROP preservation resulted in only a small immediate function. Thus the experiments indicate that COLLINS solution C2 is the optimal flush solution for ROP preservation.

Aerobiosis↗
PubMed1978

Relationship between extracellular enzymes and cell growth during the cell cycle of the fission yeast Schizosaccharomyces pombe: acid phosphatase.

By using the intact cells of the fission yeast Schizosaccharomyces pombe, the activity of acid phosphatase (EC 3.1.3.2) was compared through the cell cycle with the growth in cell length as a measure of cell growth. The cells of a growing asynchronous culture increased exponentially in number and in total enzyme activity, but remained constant in average length and in specific activity, In a synchronous culture prepared by selection or by induction, the specific activity was periodic in parallel with the increase in average cell length. When hydroxyurea was added to an asynchronous or a synchronous culture by selection, both specific and total activity followed the same continuous pattern as the growth in cell length after the stoppage of cell division. When oversized cells produced by a hydroxyurea pulse treatment to the culture previously syndronized by selection were transferred to a poor medium, they divided synchronously but could hardly grow in the total cell length. In this experimental situation, the total enzyme activity also scarcely increased through three division cycles. These results suggested that the increase in acid phosphatase in dependent on cell elongation.

Acid Phosphatase↗