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Biomedical subjects

K Aihara

Publications and source records attributed to K Aihara.

At least 109 records · Page 6Linked to original sources
PubMed1984

Zinc, copper, manganese, and selenium metabolism in thyroid disease.

This study was designed to evaluate trace metal metabolism in adults with thyroid diseases. Erythrocyte zinc values were significantly lower than normal in hyperthyroidism and higher in hypothyroidism. A significantly higher than normal urinary excretion of zinc was observed in hyperthyroidism. The mean concentrations of plasma and erythrocyte copper were significantly above normal in hyperthyroidism. Plasma selenium levels were significantly lower than normal in hyperthyroidism. No statistically significant difference was found in plasma zinc, erythrocyte manganese, or urine copper values between patients with thyroid diseases and healthy controls. The erythrocyte manganese content correlated well with thyroxine and triiodothyronine levels. Plasma prealbumin and retinol-binding protein correlated well with the erythrocyte zinc content but not with plasma zinc levels. There was no correlation between erythrocyte superoxide dismutase activity and erythrocyte copper or zinc concentrations. The results of this study suggest that the metabolism of zinc, copper, manganese, and selenium is abnormal in thyroid diseases.

Adolescent↗
PubMed1984

Effect of zinc ion on human chorionic gonadotropin-stimulated in vitro production of cyclic AMP and testosterone by rat testis.

This study explores the effects of several divalent metal ions on the in vitro production of cyclic AMP, cyclic GMP, and testosterone by rat testicular tissue and on the amount of binding of [125I]human chorionic gonadotropin (hCG) in the testis. Zn2+ at concentrations of 10(-6) to 10(-4) M enhanced the hCG-stimulated production of cyclic AMP and testosterone, but only in the presence of Ca2+ X [125I]hCG binding to rat testicular tissue was not affected by Zn2+ X Cu2+, Ni2+, Co2+, and Mn2+ did not increase cyclic AMP or testosterone production in concentrations of 10(-7) to 10(-3) M and even inhibited them at a high concentration (10(-2) M). Cyclic GMP production was not affected by these divalent ions. These results suggest that Zn2+ may play an important role in rat testicular steroidogenesis.

Animals↗
PubMed1984

A new bronchofiberscope for the study of diseases of very peripheral airways.

A new device, the BF-1.8T, has been designed to go through the 2.6 mm channel of the conventional fiberoptic bronchoscope (Olympus BF type ITR). It measures 1.8 mm in outer diameter; it has a visual angle of 75 degrees, a range of observation of 3 to 30 mm, an effective length of 950 mm, and a total length of 1120 mm. The tip can extend from the wedge of the outside endoscope by up to 180 mm, providing safe manipulation by the examiner. The results of four cases were briefly presented out of nearly 100 so far examined in our hospital. Selective alveolobronchography (SAB) was simultaneously performed because SAB could be done easily and the results were complementary to the direct observation which was obtained with the BF-1.8T. These data were also correlated with the results of transbronchial lung biopsies.

Adult↗
PubMed1983

Two stable steady states in the Hodgkin-Huxley axons.

Two stable steady states were found in the numerical solution of the Hodgkin-Huxley equations for the intact squid axon bathed in potassium-rich sea water with an externally applied inward current. Under the conditions the two stable steady-states exist, the Hodgkin-Huxley equations have a complex bifurcation structure including, in addition to the two stable steady-states, a stable limit cycle, two unstable equilibrium points, and one asymptotically stable equilibrium point. It was also concluded that two stable steady states can appear in the Hodgkin-Huxley axons when the leak current is comparable to the currents through the Na and K channels.

Animals↗
PubMed1983

[General pharmacological actions of traxanox sodium. II. Effects on the cardiovascular system].

The effects of traxanox, an anti-allergic drug, on the cardiovascular system were studied in both anesthetized dogs and cats and in isolated heart preparations from guinea-pigs. In anesthetized dogs, a very small dose of traxanox (0.01 mg/kg, i.v.) had no effect, but 0.1--30 mg/kg caused an increase in respiratory rate, hypotension, bradycardia, a transient decrease followed by an increase in renal blood flow, and a decrease in femoral blood flow. These effects were abolished by vagal block, indicating they are mediated via vagal afferents. In contrast, oral administration of traxanox (100 mg/kg) had no effect on the blood pressure or heart rate of anesthetized dogs. In anesthetized cats, traxanox (3 and 30 mg/kg, i.v.) caused a slight increase in blood pressure, but showed no effect on respiratory rate and heart rate. Both traxanox and theophylline (10(-4)M) caused increases in the beat rate of the atria and the contractile force of the papillary muscle in isolated preparations from guinea-pigs, and they potentiated the positive chronotropic and inotropic responses induced by isoproterenol. On the other hand, in anesthetized and vagotomized dogs, traxanox (3 and 10 mg/kg, i.v.) affected neither the left ventricular contractile force nor the hypotension and positive inotropic and chronotropic responses produced by isoproterenol. Administration of theophylline alone (3 and 10 mg/kg, i.v.) caused hypotension and increases in contractile force and heart rate, but it did not enhance the responses produced by isoproterenol. At doses of 1 and 10 mg/kg (i.v.), traxanox had little effect on either pressor or chronotropic responses to norepinephrine, epinephrine, DMPP and stellate cardiac nerve stimulation. The same doses of traxanox slightly reduced the depressor and chronotropic responses to isoproterenol, acetylcholine and vagus nerve stimulation. These findings suggest that traxanox had no effect on the cardiovascular systems of the animals studied in the dose range (1--5 mg/kg, p.o.) showing anti-allergic activity.

Anesthesia↗
PubMed1982

Force-velocity relationship of expiratory muscles in normal subjects.

We examined the force-velocity relationship of the respiratory muscles in normal subjects under nearly isotonic conditions, taking into consideration the pleural pressure (Ppl) changes during maximum forced expirations (MFE). We used an electromagnetic valve (EMV) to select the Ppl value at the onset of mouth flow; and both a pressure reservoir and a variable resistance to control the Ppl changes after the opening of the EMV during MFE. To simulate isotonic conditions and to obtain the shortening velocity of the contractile element (CE), we mathematically corrected the velocity of the series elastic component (SEC), using a modified version of Hill's equation. Although the maximum tension at total lung capacity (TLC) [1,156 +/- 215 (SD) g/cm] was larger than that at functional residual capacity (FRC) (782 +/- 97 g/cm) there was no significant difference in the maximum shortening velocity, 3.4 +/- 1.0 and 3.2 +/- 0.8 circumference/s at TLC and FRC, respectively. The mean values of k (slope) for the SEC at TLC and FRC were 19 +/- 4 and 18 +/- 5 circumference-1, respectively, and they were not significantly different. We concluded that the force-velocity relationship of the expiratory muscles exhibited the same mechanical properties as that of the other skeletal muscles.

Adult↗
PubMed1982

New model of a synthetic adjuvant, N-acetylmuramyl-L-alanyl-D-isoglutamine- induced arthritis: clinical and histologic studies in athymic nude and euthymic rats.

A synthetic adjuvant, N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP), induced severe polyarthritis in euthymic rnu/+ rats. The rnu/+ rats were the most susceptible to MDP-induced arthritis among various rat strains tested, whereas congenitally athymic nude rats (rnu/rnu), males or females, did not develop the disease. This disease was clinically and histologically indistinguishable from classic adjuvant-induced arthritis in terms of clinical course, clinical signs, and histologic features such as (1) an initial acute exudative reaction observed primarily in stroma of the synovial membrane, periarticular tissue, about the tendons, tendon sheath, along the periosteum, between muscle bundles and in the subcutaneous tissue; (2) hypertrophy of the synovial villi, hyperplasia of the synovial lining cells; (3) the very active periosteal new bone formation; and (4) granulation tissue growth either in the articular tissues or in liver, lymph nodes, and capsule of the spleen. Thus, it is postulated that MDP-induced arthritis is basically the same disease as classic adjuvant-induced arthritis. The thymus may play an important role in promoting the development of the disease, possibly through some immune mechanisms to undetermined antigen(s). We believe that nonimmune mechanisms may also be involved in some part of acute and chronic inflammatory reactions to MDP molecules. This new model of MDP-induced arthritis will be a very useful tool to elucidate the underlying mechanisms of adjuvant-induced arthritis.

Acetylmuramyl-Alanyl-Isoglutamine↗