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Biomedical subjects

S Takasugi

Publications and source records attributed to S Takasugi.

72 records · Page 4Linked to original sources
PubMed1978

Theoretical analysis of T-wave polarity based on a model of cardiac electrical activity.

The effect of the gradient of transmembrane action potential duration through the ventricular wall on T-wave polarity and QRS-T angle was investigated using a mathematical model of the electrical activity of the heart which incorporates the characteristic electrophysiological properties of the left ventricular wall. Two models, a rectangular solid model and a concave model, were constructed to simulate a part of the left ventricular wall. The ventricular gradient was defined as a linear decrease (beta msec/cm) of the action potential duration from the endocardium to epicardium. The theoretically-obtained relationship between the QRS-T angle and the ventricular gradient revealed that the transmural gradient (beta) was 10--40 msec/cm when the QRS-T angle was within the normal range. The positive T wave was obtained at the observation point which would correspond to the precordial lead when the transmural gradient was more than 30 msec/cm. The amplitude of the simulated T-wave increased with the ventricular gradient. Thus, our mathematical models can provide the quantitative relationship between the transmural ventricular gradient and T-wave polarity and are compatible with further simulation study for various pathological conditions.

Action Potentials↗
PubMed1977

Prediction of the effect of corticosteroid on idiopathic nephrotic syndrome based on a discriminant function.

For the purpose of discriminating between cases of nephrotic syndrome with and without corticosteroid effect, a linear discriminant function was applied in attempt to predict the effect of corticosteroid by the use of a computer. The parameters used were 15-min values of the PSP test, urinary protein, serum cholesterol, renal biospy findings, the number of red cells in the urinary sediment and immunoglobulin clearance ratio. The rate of correct prediction using the function with immunoglobulin clearance ratio was 87.0 %.

Adolescent↗
PubMed1977

[The influence of stimulation of the glossopharyngeal nerve on the gastric inhibitory and excitatory motor reflexes (author's transl)].

The influence of electrical stimulation of central cut end of the glossopharyngeal nerve on the vagal inhibitory and excitatory reflexes of gastric movements were investigated. Frogs and bullfrogs were employed in all experiments under urethan anaesthesia and also immobilized with 1% solution of d-tubocurarine chloride. Bilateral splanchnic nerves were previously severd, and so the stomach was innervated through the vagus nerves only. 1. The vago-vagal inhibitory reflex of gastric movements was depressed or abolished during the maintenance of stimulation of the glossopharyngeal nerve. But, the vago-vagal excitatory reflex of gastric movements was augmented in the one example and in the other example it was depressed during the glossopharyngeal stimulation. 2. The labyrintho-vagal excitatory reflex of gastric movements was excited during the maintenance of stimulation of the glossopharyngeal nerve.

Afferent Pathways↗
PubMed1975

Assessment of biological age by multiple regression analysis.

In order to generate a reference value of aging, estimation of chronological age of healthy subjects was made by multiple regression analysis. It was shown that the estimated ages of hypertensive subjects by the formula used were significantly higher than their chronological ages. It was further observed that parameters representing various ability of movements might yield an alternative regression formula and that the accuracy in age estimation was improved with application of a second-order regression formula.

Accommodation, Ocular↗
PubMedDate not supplied

Cartilage and labrum degeneration in the dysplastic hip generally originates in the anterosuperior weight-bearing area: an arthroscopic observation.

To clarify the intra-articular pathology of dysplastic osteoarthritis, we conducted 120 hip arthroscopies. Hips were classified radiologically into four stages: 41 prearthritic stage, 42 early-stage, 34 advanced-stage, and 3 end-stage. As the radiological stage progressed, articular cartilage degeneration became more extensive and severe. In the prearthritic and early stages, cartilage degeneration generally originated in the anterosuperior portion of the weight-bearing area of the femoral head and acetabulum. Cartilage degeneration of the acetabulum usually preceded that of the femoral head. Most detaching tears of the acetabular labrum originated in the anterosuperior area, too. In conclusion, cartilage and labrum degeneration in the dysplastic hip generally originates in the anterosuperior portion of weight-bearing area.

Acetabulum↗
PubMedDate not supplied

Chronological changes in spontaneous intracerebral hematoma--an experimental and clinical study.

A model of intracerebral hematoma that closely resembles the state in humans after spontaneous intracerebral hematoma was developed. Sequential changes in experimental intracerebral hematomas were compared with the in vivo findings in spontaneous intracerebral hemorrhage. The clinical series consisted of 28 patients with spontaneous intracerebral hemorrhage observed by CT during their natural course from 1976 through 1978. The experimental series consisted of 26 adult mongrel dogs with intracerebral hematoma near the basal ganglia studied by CT and histological examinations. In neither the clinical nor the experimental series was the time of decrease in density beginning in the periphery of the hematoma or the first appearance of ring enhancement and its concentric concentration toward the center of the hematoma affected by the size of the hematoma. In the experimental series, the tissue reaction near the periphery of the intracerebral hematoma showed constant processes: First, a necrotic layer appeared; this was then replaced by immature connective tissue with newly formed vessels and argentophilic fibers, and finally the immature layer was gradually transformed into mature connective tissue with collagenous fibers. Ring enhancement was accompanied by the appearance of immature connective tissue and capillaries. This process of change was also unrelated to the size of the hematoma. The following correlations were suggested from the chronological observation of CT images and the histological appearance: 1) acute stage - homogeneous high density extending to the periphery, appearance of the necrotic layer; 2) subacute stage - decreased density spreading from the periphery and formation of ring enhancement, appearance of immature connective tissue with argentophilic fibers; 3) chronic stage - concentric concentration of ring enhancement and development of mature connective tissue with collagenous fibers.

Animals↗