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Biomedical subjects

T Miyauchi

Publications and source records attributed to T Miyauchi.

At least 217 records · Page 12Linked to original sources
PubMed1989

Characteristics of pressor response to endothelin in spontaneously hypertensive and Wistar-Kyoto rats.

Endothelin, an endothelium-derived vasoconstrictor peptide, and angiotensin II were intravenously injected into the femoral vein of normotensive Wistar-Kyoto (WKY) rats that had been anesthetized with urethane. Blood pressure and heart rate were recorded from a cannula inserted into the carotid artery. All experiments were carried out after treatment with adrenergic and cholinergic antagonists. Endothelin showed a potent, dose-dependent pressor action. The dose-response relations for the increase in blood pressure of rats receiving endothelin were comparable with those of rats receiving angiotensin II. However, endothelin showed far more long-lasting effects. Endothelin-induced responses consisted of three phases: a rapid and transient depressor phase and then two phases of pressor (transient and long-lasting) response. Nicardipine (0.1 mg/kg), a dihydropyridine Ca2+ channel blocker, markedly attenuated the slow phase of the pressor response but only slightly attenuated the rapid one. The pressor action of endothelin was not inhibited by continuous infusions of saralasin, which almost abolished the angiotensin II-induced pressor response. Endothelin-induced pressor response was also not attenuated by indomethacin, a prostaglandin synthesis inhibitor. These data provide evidence that endothelin produces a unique, potent, and long-lasting pressor response, which appears to be in part related to the activation of Ca2+ channels. In 12-week-old spontaneously hypertensive rats (SHR), the maximal pressor response to endothelin was slightly but significantly greater than that in age-matched WKY rats, but the dose dependency of the response was approximately consistent with that in WKY rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1989

Pressor response to endothelin in guinea pigs.

Endothelin (ET), an endothelium-derived vasoconstrictor peptide, was injected into the jugular vein (i.v.) of guinea pigs anesthetized with urethane. Blood pressure was measured from a cannula inserted into the carotid artery. All experiments were carried out after treatment with adrenergic and cholinergic antagonists. ET showed a potent, dose-dependent pressor action in guinea pigs. However, the initial, transient depressor response which is observed in rats was not produced in guinea pigs. Nicardipine (0.1 mg/kg), a dihydropyridine Ca2+-channel blocker, significantly inhibited the ET-induced pressor response. These results suggest that ET causes a potent pressor response, which appears to be related to the activation of Ca2+ channels.

Animals↗
PubMed1989

Differential effects of pentobarbital and cocaine on punished and nonpunished responding.

Similar rates of punished and nonpunished responding, maintained with equated rates of reinforcement, were established in pairs of rats. One subject of each pair was exposed to a random-ratio schedule of food presentation. The interreinforcement intervals for this subject comprised the intervals of a random-interval schedule of reinforcement for the other (yoked) rat. The random-ratio schedule maintained rates of responding higher than those maintained by the same rate of reinforcement schedule according to the yoked random-interval contingency. A random-ratio schedule of electric foot shock added to the random-ratio schedule of food presentation suppressed rates of responding such that similar rates of responding were observed in rats of both groups. Pentobarbital (3.0 to 17.0 mg/kg) increased punished responding at doses that had little effect on or decreased nonpunished responding, whereas cocaine (5.6 to 30 mg/kg) increased nonpunished responding at doses that decreased or did not alter punished responding. Qualitatively different effects of pharmacological agents on punished and nonpunished responding can be obtained using procedures that generate similar rates and temporal patterns of punished and nonpunished responding. The effects of pentobarbital and cocaine on responding can be determined by factors other than simply the baseline rate of responding.

Animals↗
PubMed1989

[Usefulness of bone imaging in diagnosis of sternocostoclavicular hyperostosis].

Sternocostoclavicular hyperostosis (SCCH) is a rare disease that is characterized by hyperostosis and soft tissue ossification between the clavicles and the anterior part of the upper ribs. There have been few published reports of 99mTc-MDP bone imaging findings in this disease. Thirty-three patients who were suspected to have SCCH were studied with 99mTc-MDP bone imaging. Bone images were abnormal in 31 (94%) of 33 patients. Chest radiographs were available in 30 patients, but negative in 14 (46%) of them. Bone imaging revealed also radionuclide accumulations in other bones such as the vertebrae, femur or sacroiliac joints in ten (14 sites) of 33 cases. Bone scintigraphy was useful in the diagnosis of sternoclavicular hyperostosis.

Adult↗
PubMed1989

[Results of the treatment of carcinoma of the renal pelvis and ureter].

Twenty-one patients with renal pelvic carcinoma and eighteen patients with ureteral carcinoma were treated with surgical therapy. In 14 of the 39 patients, we performed nephroureterectomy with a bladder cuff (NUpB), nephroureterectomy with total cystectomy (NUtB) in 12, nephrectomy with partial ureteric resection (NpU) in 8 and others in 5. Following surgery, 8 had recurrences and metastasis and 21 died with carcinoma and 10 survived without evidence of disease. The 5-year survival rate of the patients with renal pelvis carcinoma is 33.5% and 52.0% in ureteral carcinoma.

Adult↗
PubMed1989

[A multimodal treatment of prostatic carcinoma and the 5-year survival rate].

One hundred and twenty-nine patients with prostatic carcinoma were treated in our hospital. They were between 49 and 88 (average, 70.3) years old and histological diagnosis was adenocarcinoma in all 129 patients; 42 had well differentiated, 55 moderately differentiated, 31 had poorly differentiated carcinomas, and one undeterminated type. Twenty two patients had stage A carcinoma, 18 stage B, 14 stage C and 75 stage D. As the therapeutic principle no castration was done, radiation therapy was delivered to cases with carcinoma more advanced than stage B in combination with estrogen or alone, and antimetabolites were given to some patients. Cryosurgical procedure to prostate was adjunctively used in patients with dysuria. Since 1986, total prostatectomy was carried out in patients with stage B disease and younger than 60 years old, and total combined resection of the urinary bladder and prostate was performed in patients with more advanced than stage C disease. Etoposide was given to patients with recurrent or metastatic lesions. Twenty-two of the 124 patients who did not receive castration surgery were categorized in stage A, 17 in stage B, 14 in stage C, and 71 in stage D. The 5-year survival rate in each stage group was 100%. 56.2%, 70.0%, and 28.8%, respectively, and the statistical difference between stage A and B, and between stage C and D was respectively significant. The relative 5-year survival rate among the total patient group, 71 patients in stage D, 40 patients in stage D treated with hormone therapy, and 15 patients in stage D treated with radiation therapy was 44.5, 28.7, 18.4 and 36.1%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1989

Involvement of calcitonin gene-related peptide in the positive chronotropic and inotropic effects of piperine and development of cross-tachyphylaxis between piperine and capsaicin in the isolated rat atria.

Piperine as well as capsaicin showed positive chronotropic and inotropic effects in the isolated spontaneously beating right atria and electrically driven left atria of rats, respectively. The responses to piperine were not affected by the presence of the antagonists to norepinephrine, acetylcholine, histamine and serotonin. However, once the tissue was pretreated with piperine or capsaicin, the response to subsequent application of piperine was reduced significantly. Both positive chronotropic and inotropic effects of capsaicin were also attenuated after the tissue was treated with piperine or capsaicin. Thus, not only a tachyphylaxis to either piperine or capsaicin itself but also a cross-tachyphylaxis between piperine and capsaicin developed. Nonadrenergic noncholinergic calcitonin gene-related peptide (CGRP)-like immunoreactive nerves were distributed in the muscle layers of both atria. CGRP-like immunoreactivity was depleted considerably by treatment of the tissue with piperine or capsaicin. When endogenous CGRP was depleted, although the positive chronotropic and inotropic effects of piperine and capsaicin were abolished, the effects of CGRP and isoproterenol were not affected. These results indicate that both piperine and capsaicin cause positive chronotropic and inotropic responses by releasing CGRP from nonadrenergic noncholinergic nerves, and that the development of cross-tachyphylaxis between piperine and capsaicin is due to the depletion of endogenous CGRP.

Alkaloids↗
PubMed1989

[EEG background activity in patients with dementia of the Alzheimer type--with special reference to analysis by t-statistic significance probability mapping (SPM) in Alzheimer's disease and senile dementia].

EEG power amplitude and power ratio data obtained from 15 (3 men and 12 women) patients with Alzheimer's disease (AD) and 8 (2 men and 6 women) with senile dementia of Alzheimer type (SDAT) were compared with similar data from 40 age- and sex-matched normal controls. Compared with the healthy controls, both patient groups demonstrated increased EEG background slowing, and it indicated more slower in AD than in SDAT. Moreover, both groups showed characteristic findings respectively on EEG topography and t-statistic significance probability mapping (SPM). The differences between AD and their controls indicated high slowing with reductions in alpha 2, beta 1 and beta 2 activity. The SPMs of power ratio in theta and alpha 2 bands showed most prominent significance in the right posterior-temporal region and delta and beta bands did in the frontal region. Severe AD indicated only frontal delta slowing compared to mild AD. The differences between SDAT and their controls indicated only mild slowing in delta and theta bands. The SPM of power amplitude showed occipital slowing, whereas the SPM of power ratio showed the slowing in the frontal region. Judging from both topographic findings, these were considered to denote diffuse slow tendency. In summary, these results presumed that in AD, cortical damages followed by EEG slowing with reductions of alpha 2 and beta bands originated rapidly and thereafter developed subcortical (non-specific area in thalamus) changes with frontal delta activity on SPM. On the other hand, in SDAT, diffuse cortico-subcortical damages with diffuse slowing on EEG topography were caused gradually.

Adult↗
PubMed1988

Effects of piperine on calcitonin gene-related peptide (CGRP)-containing nerves in the isolated rat atria.

Piperine, a major pungent agent of black peppers, induced both positive chronotropic and inotropic responses in the isolated atria of rats. These responses were not blocked by various antagonists but exhibited rapid tachyphylaxis. After exposure to piperine in vitro, endogenous calcitonin gene-related peptide (CGRP) was profoundly depleted from intracardiac nerves. These results suggest that piperine releases endogenous CGRP from intracardiac non-adrenergic non-cholinergic nerves and that released CGRP exerts positive chronotropic and inotropic effects.

Alkaloids↗
PubMed1988

Positive inotropic effects and receptors of calcitonin gene-related peptide (CGRP) in porcine ventricular muscles.

Calcitonin gene-related peptide (CGRP) in porcine ventricular muscles. positive inotropic effects in the isolated, electrically driven false tendon of the porcine heart. Specific CGRP-binding sites were present in solubilized membrane fractions; the dissociation constant (Kd) and the maximum binding (Bmax) were 50.4 pM and 180 fmol/mg protein, respectively. SDS-PAGE analysis of CGRP-binding sites revealed the molecular mass of 70 K and 120 K. Few CGRP-like immunoreactive nerves were present in the ventricular muscle layer. These results indicate that CGRP activates specific receptor sites on the ventricular muscles and causes positive inotropic responses. CGRP receptors in ventricles are likely to be activated by circulating CGRP.

Animals↗
PubMed1988

Specific effects of punishment on biogenic monoamine turnover in discrete rat brain regions.

Specific effects of punishment on the turnover rates of norepinephrine, dopamine and serotonin (5-HT) in brain regions were investigated in rats exposed to punishment. Two yoked controls were also used in an attempt to separate the non-specific effects of response rate, reinforcement density and direct effects of punisher (foot shock). Punished and unpunished littermate rats had similar response rates, and the reinforcement density was almost identical for both groups. A third group (yoked-shock rats) received food and shock independent of responding whenever these were given to the punished rats. When compared to the unpunished rats, changes in the monoamine turnover rates resulting from the punishment were similar to the effects of yoked-shock with respect to the direction of action in most cases (13 out of 17 changes). These changes may be related to non-specific effects of the shock. Four changes by the punishment were determined to be specific effects of the punishment since the yoked-shock had no effect or changed the turnover to the opposite direction. Among these, increase in 5-HT turnover rate in the frontal cortex (greater than 7-fold) was the largest change. These results and reported effects of drugs which act on serotonergic systems on the punished behavior suggest that the increase in 5-HT neuronal activity in the frontal cortex is involved in the behavioral suppression induced by the punishment.

Animals↗
PubMed1988

Specific effects of punishment on amino acids turnover in discrete rat brain regions.

Specific effects of punishment on the turnover rates of aspartate (Asp), glutamate (Glu) and gamma-aminobutyric acid (GABA) in 14 brain regions were investigated in rats exposed to punishment. Two yoked controls were also used in an attempt to separate the nonspecific effects of response rate, reinforcement density and direct effects of punisher (foot shock). Punished and unpunished littermate rats had similar response rates, and the reinforcement density was almost identical for both groups. A third group (yoked-shock rats) received food and shock independent of responding whenever these were given to the punished rats. When compared to the unpunished rats, the punishment increased the turnover rates of the three amino acids in all brain regions examined except GABA turnover in the caudate-putamen and preoptic-diagonal band. The majority of these changes by the punishment were similar to the effects of the yoked-shock (yoked-shock versus unpunished), although the magnitude of increase by the punishment was mostly larger than that by the yoked-shock. Six changes by the punishment (increase in the turnover rates of Asp in the thalamus, Glu in the hypothalamus and GABA in the cingulate cortex, entorhinal-subicular cortex, dentate gyrus and hypothalamus) appeared to be the specific effects of punishment since the yoked-shock did not affect these parameters. These results suggest that the punishment caused a hyperexcitation of the amino acidergic neurons in the limbic systems, particularly those in Papez's circuit.

Amino Acids↗
PubMed1988

Tyrosine protein kinases in membrane fractions from rat cerebral cortex.

Specific activities of tyrosine tubulin kinase in the particulate fractions from rat cerebellum, medulla oblongata, hypothalamus, striatum, midbrain, and cerebral cortex ranged within 30% of each other and more than 3 times higher than those in the soluble fractions. In the cerebral cortex, tyrosine protein kinase activity toward tubulin and tyrosine-glutamate (1:4) copolymers was mainly distributed in the plasma membrane and the microsome fractions. The kinase activity in cerebral cortex particulate fractions was quantitatively solubilized and separated into two peaks, kinase I and kinase II, by Sephacryl S-300 gel filtration in the presence of 0.2% Nonidet P-40 and 0.2 M NaCl. Kinases I and II were each resolved into 5 active peaks (I-1----5 and II-1----5) by casein-Sepharose column chromatography. The molecular weights of these kinases were estimated from the s20,w values to be 59,000-65,000. The Km values of II-1----5 for tubulin were nearly 10 times higher than those of I-1----5. However, the Km values of the two groups of kinases for tyrosine-glutamate copolymers were not so significantly different. About 60% of the copolymers kinase activity in I-3, I-4, II-3, and II-4 was immunoprecipitable with a saturating amount of monoclonal antibody against pp60c-src. Incubation of the immunoprecipitates with ATP resulted in the autophosphorylation of a 60 kDa protein in I-3 and I-4, and a 52 kDa protein in II-3 and II-4. Immunoblotting also indicated I-3 and I-4 as 60 kDa bands and II-3 and II-4 as 52 kDa bands on SDS-polyacrylamide gels.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Positron emission tomography in three cases of Lennox-Gastaut syndrome.

The true responsible lesion of Lennox-Gastaut syndrome was not adequately elucidated. Three cases of this syndrome were investigated by using Positron Emission Tomography (PET). PET revealed the differences in the left and right sides, especially the hypometabolism from the frontal to temporal regions. With this finding we supposed that the L-G syndrome implies one type of partial epilepsy caused by damage in parts of the temporal or frontal lobe.

Adult↗
PubMed1988

[Malignant melanoma of the penis associated with von Recklinghausen's neurofibromatosis: report of a case].

A 69-year-old male patient visited our clinic with complaints of dysuria and bleeding at the glans of penis on May 2, 1985. At the first presentation the tumor mass with necrotic and hemorrhagic character was localized around the urethral orifice and the entire glans of penis had a hard consistency. Moreover, numerous soft cutaneous nodules ranging from a small bean to a hen's egg in size spread over the total body surface. The nodules varied in property from even in height on the skin surface, half-spherical, and pedunculated. His family history was not contributory as far as neurofibromatosis was concerned. On May 15, the glans of penis was amputated and histological diagnosis was malignant melanoma with marked vascular and neural permeation. Review of the literature showed that our patient is the third case of malignant melanoma associated with neurofibromatosis in Japan.

Aged↗
PubMed1987

Cathepsin E from rat neutrophils: its properties and possible relations to cathepsin D-like and cathepsin E-like acid proteinases.

An extract of rat neutrophils was found to contain a high hemoglobin-hydrolyzing activity at pH 3.2, about 70% of which does not cross-react with anti-rat liver cathepsin D antibody. A neutrophil non-cathepsin D acid proteinase was successfully isolated from cathepsin D and characterized in comparison with the properties of rat liver cathepsin D. The neutrophil enzyme differed from cathepsin D in chromatographic and electrophoretic behaviors as well as immunological cross-reactivity, and its molecular weight was estimated to be 98,000 by gel filtration on Toyopearl HW 55. These findings strongly suggest that the neutrophil enzyme could be classified as cathepsin E. The enzyme, now designated rat cathepsin E, had an optimal pH at 3.0-3.2, preferred hemoglobin to albumin as substrate, and was markedly resistant to urea denaturation. Rat cathepsins D and E cleaved the insulin B-chain at six and eight sites, respectively; five sites were common for both enzymes. Possible relations among cathepsin E and cathepsin D-like or E-like acid proteinases reported so far were discussed.

Amino Acid Sequence↗