Biomedical subjects
Publications and source records attributed to T Okada.
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The uptake of catecholamines (CAs) into crude mitochondria preparations (P2 fractions) and vesicle preparations from rat hypothalamus and striatum were compared in terms of the inhibition by thymoleptics and other drugs. Thymoleptics preferentially inhibited the uptake of CAs into hypothalamic P2 fractions, while ATPase inhibitors preferentially inhibited the uptake of dopamine into striatal P2 fractions. When the preparation obtained from rats pretreated with reserpine was used, the preferential inhibition of hypothalamic uptake by thymoleptics was entirely abolished. When P2 fractions from both regions were incubated with 10(-6) M 14C-imipramine, the intrasynaptosomal distribution of labeled imipramine revealed its affinity not only to the synaptosomal membrane, but also to the synaptic vesicles. Accumulated 3H-norepinephrine (NE) could be released by a hypoosomotic shock from striatal P2 fractions, but not from hypothalamic P2 fractions. The ATP-Mg2+-dependent uptake of 3H-NE into the synaptic vesicles from rat brain stem was inhibited by desipramine. These results indicate that the inhibition of CA uptake by thymoleptics in the hypothalamus is predominantly due to the inhibition at the synpatic vesicle, while in the striatum the uptake at the synaptosomal membrane is predominantly inhibited.
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Serum and plasma samples concentrated 8 to 10 times with polyethylene glycol (PEG) having a molecular weight of 6,000 were examined by micro-Ouchterlony (MO) analysis with a view to increasing the detection sensitivity for HBe antigen (HBeAg), one of the hepatitis B virus associated antigens, and HBe antibody (HBeAb). The subjects of this investigation consisted of 82 symptom-free HBsAg carriers and 59 patients with B hepatitis. HBeAg was detected in 22 (26.8%) and HBeAb in 43 (52.4%) of 82 asymptomatic HBsAg carriers, and 17 (20.7%) were negative for both HBeAg and HBeAb. The corresponding values for the liver disease patients were 7 (11.9%), 16 (22.1%) and 36 (61.0%). Histologically, the rate of detection for HBeAg was higher in the cases of a mild disturbance.
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1. The times of appearance and the concentrations of noradrenaline and adrenaline were determined fluorimetrically in the gut of the embryonic and developing chick. 2. In the duodenum and jejunum, noradrenaline was detected in embryos on the 12th day of incubation. The concentration continued to increase throughout the embryonic stage and attained a maximum within 3 days of hatching. Afterwards, it decreased to about one-third of the peak level. No adrenaline was detectable in most stages of development. 3. In the rectum, noradrenaline was detected in embryos on the 12th day of incubation; both noradrenaline and adrenaline were invariably found on the 15th day of incubation. The concentrations of both amines fluctuated after hatching, but the amount of adrenaline was always approximately 40% of the amount of noradrenaline, except in the adult.
1 The rectum isolated from the fowl was perfused with Tyrode solution via the caudal mesenteric artery. Noradrenaline and adrenaline were biologically or fluorimetrically assayed in perfusates collected before and during stimulation of Remak's nerve or of the periarterial nerves.2 Perfusates collected during nerve stimulation relaxed the chick rectum and rat stomach strips which served as assay tissues. This effect was attributed to the action of noradrenaline or adrenaline released from adrenergic nerve endings which appeared in the perfusates.3 Perfusates obtained during stimulation (30 Hz for 60 s) of Remak's nerve contained both noradrenaline and adrenaline when measured fluorimetrically. The mean output per stimulus train was 0.8 +/- 0.2 ng/g wet wt. tissue for noradrenaline and 1.7 +/- 0.2 ng/g wet wt. tissue for adrenaline (n = 7). Perfusates obtained during stimulation (30 Hz for 60 s) of the periarterial nerves contained noradrenaline in a concentration of 1.6 +/- 0.3 ng/g wet wt. tissue per stimulus train, but almost no adrenaline (n = 7).4 Neither stimulation of Remak's nerve nor the periarterial nerves liberated catecholamines when the rectum was perfused with Tyrode solution containing low Ca(2+) (0.1 mM) and high Mg(2+) (10 mM).5 Infusion of high potassium solution (50 mM) increased markedly the output of noradrenaline and adrenaline.6 Adrenaline as well as noradrenaline may function as the adrenergic neurotransmitter in the rectum of the fowl.
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Tension-length, load-velocity and tension-extension relations were studied in the taenia coli muscle of the guinea pig weighing 0.25--0.5 kg at 36--37 degrees C. The muscle was relaxed by 10(-6) g/ml adrenaline and stimulated by a strong AC field. The tension-length diagram was far wider than that of the skeletal muscle and sufficient tension was generated at longer lengths than 1.8 Lm, where Lm is the optimal length at which the maximum tension, Fm, is generated. The developed force per unit cross-sectional area was almost unchanged between 1.2--2.0 Lm. Average of the maximum forces was 2.2 kg/cm2. Load-velocity curves obtained at various isometric forces at Lm coincided with each other, if the velocity was plotted against the relative force. All curves can be expressed by a single force-load-velocity equation, (P+A)(v+b)=b(F+A), A=(F/Fm)a, where P is the load, F the isometric force, v the velocity, a and b are constants. The maximum velocity per unit muscle length was constant, irrespective of the muscle length. The compliance of the series elastic component, that is, the slope of the tension-extension curve, did not depend on the isometric force but decreased with decreasing muscle length. The internal lengthening of the series elastic component by the full isometric tension was about 3% of the muscle length at Lm.