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Biomedical subjects

H Takeuchi

Publications and source records attributed to H Takeuchi.

At least 901 records · Page 50Linked to original sources

[Choreito and Shakuyakukanzoto: their effects on facilitating the voiding of stones in the urinary tract].

We treated 30 patients having 37 urinary calculi in all, with " Choreito " (5 g/day) and " Shakuyakukanzoto " (5 g/day) to study whether these medicines hastened spontaneous calculus excretion. Within 2 months, 91% of the small calculi (5 X 5 mm and smaller), and 33% of the medium-sized (6 X 10 mm and below) were excreted. These results were similar to those obtained with conventional conservative treatment, and suggest that this therapy will be useful.

Adult↗

Dopaminergic terminal excitability following arrival of the nerve impulse: the influence of amphetamine and haloperidol.

Variations in the excitability of the axons and terminal fields of dopaminergic neurons of the substantia nigra were examined as a function of time following the nerve impulse in urethane-anesthetized, immobilized rats. Excitability was measured by determining the threshold, defined as the minimum current required to consistently activate dopaminergic neurons antidromically. Threshold currents were maximal immediately following the action potential and declined exponentially to a plateau. The interval during which threshold current declined, the phasic period, was significantly longer for stimulation of neostriatal terminal fields as contrasted to stimulation of axons along the medial forebrain bundle. A positive correlation was observed between antidromic response latency and the duration of this phasic period for both sites of stimulation, an observation consistent with the view that the site of initiation of the antidromic action potential is of smaller diameter in the neostriatum than in the medial forebrain bundle Amphetamine, which promotes dopamine release and/or re-uptake blockade, reduced dopaminergic terminal excitability in the neostriatum at all intervals examined. This effect increased at successively shorter intervals during the phasic portion of the excitability curve. Haloperidol, a dopamine antagonist, increased the excitability of dopaminergic terminal fields, an effect which was also more marked earlier in the phasic interval. Neither amphetamine nor haloperidol had a significant effect on the excitability of dopaminergic axons in the medial forebrain bundle. Variations in dopaminergic terminal excitability after impulse arrival, and the effects of amphetamine and haloperidol on this phenomenon suggest that terminal excitability is determined by events related to arrival of the nerve impulse including activation of presynaptic 'autoreceptors' by dopamine released from the synaptic ending.

Amphetamine↗

Rhabdomyosarcoma-induced hypercalcemia in a nude mouse.

Hypercalcemia in nude mice with a rhabdomyosarcoma transplanted from a hypercalcemic patient is reported. The tumor had been transplanted to nude mice from a 15-year-old girl with hypercalcemia which appeared as the rhabdomyosarcoma developed and metastasized to the peritoneal and pleural cavities. The tumor was successfully transplanted to nude mice, which presented an elevated serum calcium level. No remarkable elevation of serum parathyroid hormone or 1 alpha, 25-dihydroxyvitamin D was found in the mouse with rhabdomyosarcoma. Injection of indomethacin restored the elevated serum calcium level to the normal range. The prostaglandin E2 level was approximately 15 times higher in the tumor-bearing mouse serum than in the control mouse serum. These data indicate that hypercalcemia in this patient can be ascribed to prostaglandin E2 produced by the rhabdomyosarcoma.

Animals↗

Treatment of infected urinary stones in rats by a new hydroxamic acid, "N-(pivaloyl)glycinohydroxamic acid.

The effectiveness of a new urease inhibitor, N-(pivaloyl)glycinohydroxamic acid, in the treatment of infected urinary stones was investigated. The hydroxamic acid markedly inhibited and alkalinisation of urine and stone formation when it was administered orally to rats with urinary tract infection caused by Proteus mirabilis; its inhibitory effect was potentiated by concomitant treatment with Cephalexin. This compound may become a useful medicine for the treatment of struvite stones.

Animals↗

Effects of N-beta-phenylpropionyl-L-tyrosine and its derivatives on the excitability of an identifiable giant neuron of Achatina fulica férussac.

1. Previously the authors demonstrated the inhibitory effects of the two aromatic amino acid derivatives, N-beta-phenylpropionyl-L-Tyr (critical concentration (c.c.), 3 x 10(-7) - 10(-6) M) and N-beta-phenylpropionyl-L-Trp (c.c., 10(-6) M) on the excitability of an identifiable giant neuron, TAN (tonically autoactive neuron), of Achatina fulica Férussac. The effects of the derivatives of the two inhibitory compounds on the same neuron are examined in the present study. 2. N-beta-Cyclohexylpropionyl-L-Tyr (c.c., 3 x 10(-8) - 10(-7) M) and N-beta-cyclohexylpropionyl-L-Trp (c.c., 10(-6) M) had marked inhibitory effects, whereas N-beta-p-methyl-phenylpropionyl-L-Tyr had none. 3. N-gamma-Phenylbutyroyl-L-Tyr and N-phenylacetyl-L-Tyr, in which the chain length of the phenyl group is different, had no effect. 4. N-beta-Phenylpropionyl-N-methyl-L-Tyr, in which the imino group of the peptide bond is methylated, had no effect. 5. N-beta-Phenylpropionyl-L-Tyr (c.c., 3 x 10(-7) - 10(-6) M) and N-beta-phenylpropionyl-L-Tyr methylester (c.c. 1-3 x 10(-6) M) had marked inhibitory effects, suggesting that their carbonyl group acts as a proton acceptor. 6. N-beta-Phenylpropionyl-L-p-hydroxyphenylglycine, in which the chain length of the hydrogen binding group is shorter, had no effect. 7. N-beta-Phenylpropionyl-L-3,4-dihydroxy-Phe (c.c., 3 x 10(-6) M), N-beta-phenylpropionyl-L-3-nitro-Tyr (c.c., 3 x 10(-5) M) and N-beta-phenylpropionyl-L-p-amino-Phe (c.c., 3 x 10(-5) - 10(-4) M) had inhibitory effects, weaker than that of N-beta-phenylpropionyl-L-Tyr. N-beta-Phenylpropionyl-L-p-chloro-Phe and N-beta-phenylpropionyl-L-p-nitro-Phe showed the same effect only at high concentrations.

Animals↗