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Biomedical subjects

T Morishita

Publications and source records attributed to T Morishita.

At least 19 recordsLinked to original sources
PubMed1992

Effects of islet amyloid polypeptide (amylin) and calcitonin gene-related peptide (CGRP) on glucose metabolism in the rat.

In this study, we compared the effects of islet amyloid polypeptide (IAPP) and calcitonin gene-related peptide (CGRP) on glucose metabolism both in vivo and in vitro in the rat. Intravenous injection of rat CGRP caused a significant increase in plasma glucose concentration with a simultaneous increase in plasma insulin levels, whereas neither IAPP-NH2 nor IAPP-COOH had any effect. Moreover, intravenous infusion of CGRP decreased tolerance to intragastric administration of glucose (O-GTT) without altering plasma insulin levels, but again IAPPs had no effect. On the other hand, 125I-[Tyr0]rat CGRP specifically bound to the liver plasma membrane, and not only CGRP but also IAPP-NH2 dose-dependently displaced the specific binding of 125I-[Tyr0] CGRP, whereas IAPP-COOH had no effect. Conversely, CGRP as well as IAPP-NH2 but not IAPP-COOH evoked dose-dependent activation of adenylate cyclase in the membranes, and these effects were significantly inhibited by a CGRP receptor antagonist, human CGRP-I(8-37). However, neither CGRP nor IAPP-NH2 had any effect on glucose production in rat isolated hepatocytes. These results suggest that (1) IAPP-NH2 but not IAPP-COOH induces adenylate cyclase activation via CGRP receptors on rat liver plasma membranes, and (2) CGRP might not involve its action on the liver in the changes of glucose metabolism.

Amyloid↗
PubMed1992

Regional differences of phospholipase A2 activity in the rabbit oviductal epithelium.

To evaluate the biosynthesis of prostaglandins in the oviducts, phospholipase A2 (EC 3.1.1.4) activities were first measured in the epithelial cells obtained from rabbit oviducts. At least four kinds of phospholipase A2 (PLA2) activities with respect to calcium dependency and pH requirement were observed. There were two calcium-dependent, pH optima of 7.5 and 8.5 activities, and two calcium-independent, pH optima of 4.0 and 8.0 activities. One of those activities, a calcium-dependent and alkaline active PLA2 activity of the epithelial cells was then compared between the ampullary portion and the isthmic portion of the oviducts. The activity was significantly higher in the ampullary epithelium than in the isthmic epithelium (223.2 +/- 57.2 or 103.8 +/- 32.3 pmol/min/mg, p < 0.05). These results support the idea that the production of prostaglandins, which is dependent upon the activity of the arachidonate cascades, was higher in the ampullary portion of oviduct than that in the isthmic portion. The PLA2 activity of the ampullary epithelium may thus play an important role in the regulation of smooth muscle contractility and ciliary movement.

Animals↗
PubMed1992

[Rapid diagnosis of influenza infection by PCR method--detection of influenza virus HA gene in throat swab].

We studied the detection of the HA gene of human influenza viruses in throat swabs obtained from the outbreaks of influenza in school children utilizing the polymerase chain reaction (PCR) method. Sensitivity and specificity of the PCR method was compared to conventional virus isolation using MDCK cells. Three pairs of primers for PCR in detecting the HA genes of AH1, AH3, and B influenza viruses showed both subtype and type specificity. The dilution experiments showed that influenza viruses, as few as 1.1-3.5 plaque-forming units per 50 microliters, were sufficient for the detection of HA genes by PCR method and the detection rate by PCR method was 2-3 fold higher than that by conventional method. Our results showed that the PCR method was a fast, sensitive and reliable method for the diagnosis of influenza infections.

Base Sequence↗
PubMed1992

[Evaluation of myocardial disorders in patients with dilated cardiomyopathy and left ventricular eccentric hypertrophy--by 201Tl myocardial SPECT].

201Tl myocardial SPECT was performed in cases of dilated cardiomyopathy and valvular heart disease with left ventricular eccentric hypertrophy, and the two groups were compared from the standpoint of the mechanism of onset of myocardial disorders. Significant coefficients of correlation were seen between the Tl score and LVDd (r = 0.792, r = 0.785) and Tl score and LVEF (r = -0.634, r = -0.555) in both dilated cardiomyopathy and valvular heart disease. In cases of valvular heart disease, significant correlation coefficients (r = -0.756, r = -0.720) between LVDd and r-WR (relative-washout rate), and Tl score and r-WR were observed, but no such correlation was seen in dilated cardiomyopathy. In valvular heart disease, a decrease in myocardial perfusion associated with enlargement of the left ventricle appeared, while in dilated cardiomyopathy, there was a marked decrease in LVEF in proportion to the thallium defect. Therefore, it was assumed that left ventricular wall disorders occur due to myocardial metabolic disorders and coronary microcirculation disorders.

Adult↗
PubMed1992

[Pulmonary thromboembolism associated with myelodysplastic syndrome].

We present a 65-year-old female with myelodysplastic syndrome (MDS) who has attended our O.P.D. since 1983. In early December, 1990, dyspnea on effort developed which then progressed to dyspnea at rest at the end of December. She was admitted on January 8 with orthopnea. Chest X-ray films revealed loss of vascular shadows of the right lung. Blood gas analysis showed hypoxemia and hypocapnemia. Abnormalities in the coagulation-fibrinolytic system (increased TAT (thrombin-anti-thrombin III complex) and alpha 2-PIC (plasmin inhibitor complex)), possibly due to MDS, were detected. The diagnosis of pulmonary thromboembolism was made by pulmonary perfusion scintigram and pulmonary arteriography. After commencement of anticoagulation therapy on January 15, the subjective symptoms, blood gas analysis, pulmonary scintigram, and disorders of the coagulation-fibrinolytic system improved. The patient was discharged on March 5, 1991. The present case of myelodysplastic syndrome was associated with abnormalities of the coagulation-fibrinolytic system and was complicated by pulmonary thromboembolism.

Aged↗
PubMed1991

Receptors for gastrin on gastric carcinoid tumor membrane of Mastomys natalensis.

Specific binding sites for human gastrin I (gastrin) were identified in a crude membrane preparation from the gastric carcinoid tumor of Mastomys (Praomys) natalensis. The binding of 125I-gastrin to the carcinoid tumor membrane was saturable, and Scatchard analysis of the data revealed a single class of binding site with a dissociation constant of 139.2 pM and a maximal binding capacity of 23.5 fmol/mg protein. Gastrin and CCK8 equipotently and dose-dependently displaced the binding of 125I-gastrin to the membrane. GTP but not ATP decreased 125I-gastrin binding to the membrane, and removal of Mg2+ attenuated this inhibitory action of GTP. The GTP-induced reduction of 125I-gastrin binding was found to be due to a decrease in binding affinity without a change in binding capacity. These results clearly indicate the presence of specific binding sites for gastrin, probably coupled to guanine nucleotide-binding protein, in the carcinoid tumor membrane of Mastomys, and suggest that gastrin has possible biological actions on these tumors.

Adenosine Triphosphate↗
PubMed1991

Involvement of superoxide anion and platelet-activating factor in increased tissue-type plasminogen activator during rat gastric microvascular damages.

The role of tissue-type plasminogen activator (t-PA) was investigated in the gastric ulcer formation induced by microvascular derangement. The rat stomach was exposed and repeated electrical stimuli (irritation) were applied on the small arterial wall close to the lesser curvature to induce mucosal ischemia followed by hyperemia. The t-PA activity in the regional blood of the stomach was significantly elevated as early as 5 min after the irritation. Immunohistochemical study using anti-t-PA monoclonal antibody revealed that t-PA was detectable in the endothelial cells of capillaries and collecting venules, suggesting the involvement of endothelium-mediated fibrinolytic activity in the irritation-induced ulcer formation. Pretreatment of SOD or allopurinol significantly attenuated the irritation-induced t-PA activation, suggesting that the t-PA activity was modulated by xanthine oxidase-associated superoxide anions. CV-6209, a selective antagonist of platelet-activating factor (PAF), also prevented the activation of t-PA as well as ulcer formation, providing a concept that PAF may be associated with the local fibrinolytic activation which may cause hemorrhagic changes in the gastric mucosal microvasculature. The present study supports the hypothesis that increased t-PA activity may reflect the microvascular endothelial damages caused by vasomotor derangement and suggests that oxygen-derived free radicals may participate in the regulation of endothelium-derived fibrinolytic activities in the mucosal microvasculature.

Animals↗
PubMed1991

A large outbreak of gastroenteritis associated with a small round structured virus among schoolchildren and teachers in Japan.

In March 1989 a large outbreak of acute gastroenteritis occurred simultaneously among schoolchildren and teachers at nine elementary schools in Toyota City, Japan. Illness was observed in 3236 (41.5%) of 7801 schoolchildren and 117 (39.4%) of 297 teachers. The main clinical symptoms were diarrhoea, vomiting, nausea and abdominal pain. Gastroenteritis was significantly associated with the consumption of school lunch served by one particular lunch preparation centre. One food handler at the centre suffered from gastroenteritis during the outbreak. Small round structured virus (SRSV) was detected in 4 of 8 stool specimens from sick persons. The school lunch contaminated by the infected food handler is the most probable source of this outbreak due to SRSV.

Abdominal Pain↗
PubMed1991

A dominant interfering mutation (CYR3) of the Saccharomyces cerevisiae RAS2 gene.

The dominant cyclic AMP-requiring mutation CYR3 had been previously reported as a mutation in the regulatory subunit of cyclic AMP-dependent protein kinase. However, recharacterization revealed that the CYR3 mutation was a nonconditional dominant lethal mutation and was a missense allele of RAS2 which results from the substitution of aspartic acid for glycine at amino acid 22.

Fungal Proteins↗
PubMed1991

Genetic and molecular analyses of the SUP201 gene: a tRNA(3Arg) nonsense suppressor of yeast cyrl-2.

The temperature-sensitive cyr1-2 mutant in Saccharomyces cerevisiae produces low levels of adenylate cyclase and cyclic AMP at 25 degrees C and is unable to synthesize repressible acid phosphatase at 25 degrees C. Suppressor mutants of cyr1-2 were isolated by detecting acid phosphatase activity. One of the dominant suppressor mutations isolated was designated SUP201 and characterized. The SUP201 mutant gene was isolated from a gene library made from cyr1-2 SUP201 mutant DNA. Nucleotide sequence analysis of the cloned SUP201 gene revealed that the SUP201 gene was a mutated tRNA gene flanking GCN4, which worked as a UGA suppressor.

Base Sequence↗
PubMed1991

Effect of intestinal microflora on digestible energy and fiber digestion in chickens fed a high-fiber diet.

The effect of intestinal microflora on digestible energy (DE) value and fiber digestion was studied in single-comb White Leghorn chickens fed a low-fiber diet (experiment 1) or a high-fiber diet with low or adequate metabolizable energy (ME) value (experiment 2). Fecal energy excretion was calculated from the difference between total energy excretion in urinary and fecal droppings and urinary energy excretion, which was estimated from the energy values for individual urinary nitrogenous compounds extracted with Li2CO3. When the birds were fed the low-fiber diet, no differences in growth, DE, or ME were observed between germ-free and conventional environments. Of birds fed the high-fiber diet, growth of those in the conventional environment was similar to that of the birds in the germ-free environment at the adequate ME value, whereas birds in the conventional environment grew faster than the birds in the germ-free environment at the low ME value. Changes in observed dietary ME values of the high-fiber diets, being higher in birds in the conventional environment than in birds in the germ-free environment (experiment 2), were almost entirely accounted for by those in dietary DE values, most of which was contributed by crude fiber digestion. It was concluded, therefore, that by means of fiber digestion, the intestinal microflora may benefit the host bird by supplying extra energy, which would result in growth promotion, particularly when the bird is deficient in energy.

Animals↗
PubMed1991

[Left ventricular wall damage as an indicator for valve replacement in patients with volume overload: a radionuclide study].

Using Tl-201 myocardial single photon emission computed tomography (SPECT), we tried to utilize the Tl-defects to determine the timing for aortic or mitral valve replacement in cases with chronic aortic (AR) or mitral regurgitation (MR), or both. Examinations including echocardiography and angiography were performed to evaluate left ventricular dilatation. Subjects consisted of 80 patients, including 22 with AR, 26 with MR, 17 with AR+MR, and 15 post-operative cases. The Tl-scores (sum of the grade of Tl-defects) correlated well with T wave abnormalities (V5) and NYHA functional class. The scores also correlated with left ventricular end-diastolic dimension (LVDd) and LV ejection fraction (LVEF), indicating that the LV wall defect progressed as the LV dimension increased with the increase in the volume load. Exercise Tl-201 myocardial SPECT revealed redistribution at an early stage of valvular regurgitation, indicating the development of LV wall damage in cases of LV enlargement due to regurgitation. Valve replacement caused a decrease in LVDd, with mild improvement in the Tl-score. We concluded that, in addition to the T wave changes and the echocardiographic measurements, Tl-201 myocardial SPECT should be included in the criteria for valve replacement.

Aortic Valve Insufficiency↗
PubMed1991

[Evaluation of myocardial blood flow and cardiac functional change in acromegaly].

We studied 201Tl myocardial scintigraphy and 99mTc-HSA gated blood pool scan to evaluate the influence of growth hormone on myocardial blood flow and hemodynamics in 16 patients with acromegalies. Contraction properties were almost within normal limit, but cardiac output was in high output state, because left ventricular ejection fraction (LVEF), right ventricular ejection fraction (RVEF) and cardiac output were 47.8 +/- 17.1%, 37.3 +/- 14.9%, and 6.4 +/- 1.7 L/min, respectively. Otherwise, 201Tl myocardial images revealed 62.5% no redistributed hypoperfusion, 18.8% redistributed hypoperfusion, 56.3% myocardial hypertrophy and 25.0% left ventricular enlargement. These data suggested the high incidence of acromegalic cardiomyopathy due to primary or secondary growth hormone effect.

Acromegaly↗
PubMed1990

Evaluation of viral myocarditis in children by radionuclide method.

Evaluation of viral myocarditis is essential for the clinician to assess the prognosis. In this study, Tl-201 myocardial scintigraphy and Tc-99m gated cardiac blood pool scan were performed in 16 patients with myocarditis diagnosed by clinical symptoms and laboratory findings and these nuclear medicine techniques were followed up for 5 years. Exercise Tl-201 scintigraphy using a bicycle ergometer was performed in 8 patients by SPECT imaging. There were mild to severe persistent defects found in all cases (100%), but pressure rate products showed normal response. The Tl-201 defect ratio improved gradually, but did not change significantly. In the resting Tl-201 image one of 16 patients showed severe multifocal defects. LVEF increased significantly from 1 year to 5 years after onset, while RVEF measured by gated blood pool scans showed slight increases 3 years to 5 years after diagnosis. It was concluded that myocardial perfusion improved only incompletely. Cardiac function (LVEF and RVEF) improved gradually, and pressure rate products were normal. Myocarditis should therefore be followed up in order to assess the prognosis; moreover, the relationship of myocarditis to dilated cardiomyopathy needs to be further studied.

Child↗