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Biomedical subjects

M Tamura

Publications and source records attributed to M Tamura.

At least 775 records · Page 43Linked to original sources
PubMed1988

Purification and characterization of specific endogenous ouabainlike substance from bovine adrenal.

Endogenous inhibitors of Na, K-ATPase have been implicated in the pathogenesis of salt-induced hypertension. Despite an intensive search, the inhibitor(s) have long remained elusive. We have been able to purify such an inhibitor from methanol extracts of bovine adrenal glands by multiple steps of high-performance liquid chromatography (HPLC). This compound showed striking similarity to the cardiac glycoside ouabain in its dose dependency in the inhibition of Na, K-ATPase and Na-pump activity, competitive binding to the ouabain-binding site, and dependence of these effects on K+ concentration. These results indicate that vertebrate animals contain a regulator of Na, K-ATPase.

Adrenal Glands↗
PubMed1988

Cell-mediated immunity to virus causing haemorrhagic fever with renal syndrome: generation of cytotoxic T lymphocytes.

Cytotoxic T lymphocytes (CTLs) were generated when spleen cells from mice infected with viruses causing haemorrhagic fever with renal syndrome were stimulated in vitro with syngeneic cells infected with viruses. These cytotoxic effector cells, with Lyt2+ L3T4- markers on their surface, demonstrated H-2 restriction. CTLs induced by Hantaan virus (76-118 strain) or Seoul virus (B-1 strain) showed cross-reactivity with infected target cells. Hantaan virus infection induced a higher CTLs response than Seoul virus infection, although the antibody responses to these two viruses and the replication of the two virus strains in athymic nude mice were not significantly different. Viral antigen detected with a monoclonal antibody reacting with nucleocapsid antigen was observed mainly in the cytoplasm of macrophages infected with Hantaan virus, but in the nucleus of cells infected with Seoul virus. The major viral antigens recognized by CTLs are discussed on the basis of these findings.

Animals↗
PubMed1988

Quantitative analysis of hemoglobin oxygenation state of rat brain in situ by near-infrared spectrophotometry.

The light in the near-infrared region (700-900 nm) was illuminated on the rat head, and absorption spectra were measured with the transmitted light under various conditions. The absorbance changes less than 780 nm were attributable to hemoglobin in the brain tissue, whereas those greater than 780 nm were associated with both hemoglobin and cytochrome oxidase. The changes of oxy- and total (oxy- plus deoxy-) hemoglobin content in the rat head could be monitored quantitatively by expressions of delta A700--1.20 delta A730 and delta A700--1.52 delta A730, respectively. The oxyhemoglobin content in the tissue was decreased as the O2 tension in inspired gas was lowered. At 10% O2 approximately 50% of hemoglobin was deoxygenated. The total hemoglobin content was increased under anoxic conditions. Inhalation of 5% CO2 and intravenous injection of a Ca2+ blocker nicardipine increased the O2 saturation of hemoglobin in the brain. These conclusions were confirmed by measuring the difference absorption spectra in the near-infrared region.

Animals↗
PubMed1988

Recurrence of subacute thyroiditis over 10 years after the first attack in three cases.

We saw a total of 4 episodes of the recurrence of subacute thyroiditis in 3 patients out of 222. The recurrent episodes were similar to the first episodes of subacute thyroiditis. The titers of various viral antibodies were not increased significantly during the clinical course of the recurrence. Regarding the HLA typing, A26, B35 and C3 were positive in all 3 patients. The association between the occurrence of subacute thyroiditis and the presence of HLA-B35 and C3 has hitherto been reported, although the association of HLA-A26 with recurrent type of subacute thyroiditis was observed and described for the first time in this report. It is suggested that HLA-A26 may somehow be related to the predisposition to the recurrence of subacute thyroiditis which developed after more than 10 years.

Adult↗
PubMed1988

A case of arrhythmogenic right ventricular dysplasia with prominent late potential.

A case of arrhythmogenic right ventricular dysplasia with frequent episodes of ventricular tachycardia (VT) in a 57-year-old man is reported. His electrocardiogram showed a normal axis and inverted T waves in V1-V3 during sinus rhythm and a left bundle branch block pattern during VT. The VT could be terminated by either intravenous administration of lidocaine or procainamide or by cardioversion. Echocardiogram and right ventriculography showed reduced wall motion of the apex and infundibulum of the dilated right ventricle. No evidence of ischemic heart disease was found by left ventriculography, coronary arteriography and RI scintigraphy. A prominent late potential following the QRS complex was recorded by averaging and magnifying the surface electrocardiogram. The combination of oral mexiletine and disopyramide partially suppressed the VT attacks and relieved the subjective symptoms, however the late potential remained almost unchanged.

Cardiac Pacing, Artificial↗
PubMed1988

[Treatment of delayed brain injury after pituitary irradiation].

Treatment for delayed brain injury after pituitary irradiation is discussed. Six cases with delayed brain injury were treated with a combination of dexamethasone or betamethasone, with heparin, glycerol, dextran 40 and some vasodilators. Two cases with temporal lobe syndrome were treated in the early stages of brain injury for a period of over 12 months were almost completely cured, another two cases with chiasma syndrome were treated in the relatively late stages, showed a partial improvement. One case which was irradiated 120 GY during 13 years did not improve. The final case treated with steroids for a short period also resulted in failure and the patient underwent an operation for the removal of the necrotic mass three years after the radiotherapy. Steroid therapy started in the early stages of brain injury after irradiation for over the 12 months is thought to be effective. Heparin therapy was also effective in one out of three cases, but in one of the cases subarachnoid hemorrhage from a traumatic aneurysm occurred during the therapy. In an acute phase, showing edematous change of the injured brain, the administration of glycerol is also thought to be useful. But the effectiveness of the other medicines containing some vasodilators was obscure or doubtful. We propose the following: (1) A meticulous observation is essential for the patients who received high doses of irradiation to diagnose brain injury in the early reversible stage. (2) Steroids should be given immediately in this reversible stage of brain injury before the irreversible "necrosis" occurs. (3) Steroids should be maintained for a long period over 12 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1988

[Radiation therapy of intracranial germ cell tumors].

The results of radiation therapy in 31 patients with intracranial germ cell tumors have been analyzed. The five-year survival rates were 70.1% for germinomas and 38.1% for teratomas. Three patients with germinoma have since died of spinal seeding. The prophylactic irradiation of the spinal canal has been found effective in protecting spinal seeding, since no relapse of germinoma has been observed in cases that received entire neuraxis irradiation, whereas teratomas and marker (AFP, HCG) positive tumors did not respond favorably to radiation therapy, and the cause of death in these patients has been local failure. Long-term survivors over 3 years after radiation therapy have been determined as having a good quality of life.

Adolescent↗