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Biomedical subjects

T Sone

Publications and source records attributed to T Sone.

At least 199 records · Page 11Linked to original sources

[Reversible ischemic myocardial damage: clinical observation using two-dimensional echocardiography].

Acute myocardial ischemia followed by protracted asynergy and subsequent resolution was defined as reversible ischemic myocardial damage. The purpose of this study was to confirm the existence of this entity and to illustrate the clinical features. The subjects consisted of 26 patients with typical acute myocardial ischemia who satisfied the above definition, and serial changes in left ventricular wall motion were observed by two-dimensional echocardiography. The left ventricle was divided into 11 segments and the movement was scored according to the dynamic behavior of each segment by five points ranging from normal (0) to dyskinesis (4), and evaluated semiquantitatively using the total score sum as the total asynergy score. Compared to the initial value, this score decreased to 57% after one week, 38% in two weeks, 22% in three weeks and 17% in four weeks. The asynergy persisted 23.7 +/- 13.5 days and ranged from two days to three months. The peak CPK ranged from 32 to 561 IU (mean 212 +/- 157 IU). Coronary arteriography revealed undisturbed flow of the responsible artery in both acute and chronic phases including four cases of successful PTCR. Comparison of the electrocardiographic changes and asynergy showed that diminished R wave amplitude, ST segment elevation and inverted T waves are frequently associated with persistence of asynergy, extensive asynergy can even occur in cases without a diminished R wave or abnormal Q wave and when asynergy resolves, ST segments tend to return to the baseline, but T wave inversion commonly persists. A transient Q wave was observed in 38% of the patients examined. The electrocardiogram became normal in an average of 111.3 +/- 75 days. In conclusion, there is a subgroup of reversible asynergy among cases of unstable angina pectoris or subendocardial infarction. The mechanism for this may be myocardial "stunning" following transient transmural ischemia. Recognition of this fact seems very important in the diagnosis and treatment of acute myocardial ischemia.

Adult↗

Cd2+-induced synthesis of metallothionein in HeLa cells.

HeLa cells synthesize metallothioneins in response to Cd2+. The kinetics of thionein (apoprotein of metallothionein) synthesis was studied by pulse-labelling the cells with [35S]cysteine and measuring relative amounts of the labelled thioneins separated by electrophoresis. Thionein synthesis rapidly increases in the first 6-8 h after exposure to 0.5 micrograms of Cd2+/ml, and begins to decrease in a few hours after reaching the maximum. However, the rate of synthesis never returns to the basal value at least in 30 h after Cd2+ exposure; instead, the second increase in thionein synthesis occurs at 16-18 h. A possible regulatory mechanism of thionein synthesis is discussed from these results, together with the data on intracellular accumulation and subcellular distribution of 109Cd2+. The initial increase of thionein synthesis is accompanied by an increase of mRNA coding for thioneins (MT-mRNA). The induction of MT-mRNA is sensitive to Actinomycin D, but not to cycloheximide, suggesting transcriptional regulation without any mediating protein synthesis. Two thionein isomers are coded for by mRNA molecules of almost the same size, which is similar to that of hepatic MT-mRNA of mouse and rat.

Cadmium↗

Induction of metallothionein synthesis in cultured cells derived from rabbit kidney.

Metallothionein (MT) synthesis in rabbit kidney-derived RK-13 cells was studied. In response to Cd2+, RK-13 cells synthesized proteins closely similar in chromatographic and electrophoretic behaviors to the liver MTs induced in Cd2+-injected rabbit. These proteins were specifically immunoprecipitated by anti-mouse liver MT-II serum. The rate of RK-13 thionein (apoprotein of MT) synthesis rapidly increased after exposure to 1 microgram/ml of Cd2+, and reached the maximum in 7 h. The dose-response curve for the synthesis was biphasic; a sharp increase up to 0.5 microgram/ml and a slower increase at higher concentrations. RK-13 cells retained kidney-specific properties in terms of responsiveness of thionein synthesis to inducers; The MTs were inducible also by Zn2+ and probably by Hg2+, but not by dexamethasone. This system would therefore be a useful model in vitro for studying the regulation of MT synthesis in kidney cells.

Animals↗

The usefulness of bone-marrow scintigraphy in the detection of bone metastasis from prostatic cancer.

We used a combination of bone and bone-marrow scintigraphy to study 25 patients with prostatic cancer. Of the 18 cases whose 99mTc-methylene diphosphonate (MDP) bone scans showed hot spots in the lower lumbar region of the spine and/or the pelvic bone, 8 had normal bone-marrow scintigrams. These 8 patients were subsequently shown to have senile, degenerative changes of the spine. On the other hand, in 9 of the 10 patients whose bone-marrow scintigrams showed accumulation defects, follow-up study and characteristic X-ray findings confirmed the presence of metastases. In all 6 cases with extensive bone metastases shown by 99mTc-MDP bone scintigraphy, 99mTc-sulphur-colloid bone-marrow scintigraphy showed multiple accumulation defects. In conclusion, bone-marrow scintigraphy was found to be useful in distinguishing metastatic lesions from benign degenerative changes in the cases with suspected bone involvement, as well as in evaluating equivocal lesions in the pelvis.

Aged↗

A case of synovial sarcoma with bone metastasis identified by bone marrow scintigraphy.

In a patient with synovial sarcoma, routine bone survey showed no abnormality, while bone marrow scintigraphy with Tc-99m sulfur colloid revealed a defect in the fifth lumbar vertebra. At surgery, tumorous invasion was noted in the fifth lumbar vertebra and the surrounding tissues. It was suggested that the bone marrow scintigraphy was particularly useful in the detection of tumorous invasion into the bone marrow at the early stage before the destruction of skeletal tissue.

Adolescent↗

p-Nitrophenyl vinyl ether, a novel substrate for the assay of cytochrome P-450 dependent olefinic epoxidation in hepatic microsomes.

p-Nitrophenyl vinyl ether (NPVE) was metabolized to p-nitrophenol and glycolaldehyde via an epoxide by rat hepatic microsomes. The cofactor requirement and effects of monooxygenase inhibitors indicated that the oxidative metabolism of NPVE was mediated by microsomal cytochrome P-450. Epoxide hydrolase plays a minor role, because a strong epoxide hydrolase inhibitor, 3,3,3-trichloropropene oxide, showed a weak inhibitory effect on the p-nitrophenol formation. The epoxy intermediate is so labile that the hydrolysis of the epoxide proceeds mostly nonenzymically even at a neutral pH. Induction experiments suggested that NPVE was susceptible to a wide varieties of cytochrome P-450 species. Thus, a convenient and sensitive method for the assay of olefinic epoxidase activity in hepatic microsomes was developed with NPVE as a substrate.

Animals↗

Problems of artificial pacemaker therapy.

Four hundred and sixty-seven cases with implantation of an artificial pacemaker were studied. The postoperative survival rate was 63% for 15 years. Seventy-two percent of type III patients of the sick sinus syndrome were free from postoperative thromboembolism and the lowest of the three types of the sick sinus syndrome. Comparing postoperative physical activity, cardiothoracic ratio and exercise tolerance time, physiological pacing was superior to ventricular pacing in hemodynamic effects and clinical symptoms. In a hundred cases of physiological pacing, complications and problems of physiological pacing were discussed. Atrial sensing failure and over-sensing were observed in seven and two cases respectively. A low amplitude of atrial potential and use of unipolar atrial leads were considered to be the main causes of these complications. Bipolar lead should be used as the atrial lead to avoid such complications, because the atrial potential by bipolar leads is not less than that by unipolar leads. Atrial sensing may be more sensitive without electromagnetic interference. The fixed A-V delay time whenever the atrium is sensed or paced, often results in a ventricular fusion beat and hemodynamic change on every beat, according to the interval of atrial and ventricular contractions. The A-V delay time should be changed in accordance with atrial sensing or pacing.

Cardiac Pacing, Artificial↗