Biomedical subjects
Publications and source records attributed to H Murakami.
A new method for estimating the activity of a mouse by means of the photoswitch is contrived. This device can follow the activity with high fidelity and notable sensitivity, as compared with the conventional method.
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1,3,5-trichloro-2-(4-nitrophenoxy)benzene (CNP), a widely used herbicide in Japan, has been identified in environmental biota for the first time. CNP was isolated from mussel collected in Tokyo bay and confirmed by GC-MS, IR and UV spectra. The level of CNP in the mussel sample was approximately 1 ppm on wet basis.
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Effect of methionine-, leucine-enkephalin (met-, leu-enkephalin) and substance P on the transmission in mouse vas deferens was studied. Both met- and leu-enkephalin inhibited electrically induced contraction of vas deferens at 10(-8)-10(7) M, met-enkephalin being 1.4 times more active than leu-enkephalin. Nalorphine (10(-6) M) antagonized these effects. Substance P (10(-9)-10(-7) M) had no effect on the contraction. Met- and leu-enkephalin (10(-7)-10(-5) M) decreased the high potassium induced [3H]-norepinephrine release from vas deferens, while substance P (10(-6) M) significantly increased it. Nalorphine (10(-5) M) reversed the inhibitory effect of met-enkephalin. These results indicate that these peptides modify the transmission of sympathetic nerve in mouse vas deferens.
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Influences of verapamil, X-537A, A-23187 and cyclic-AMP on the release of [3H]-5-HT taken up into rat brain slices, were examined. Incubation with 40 mM KCl induced tritium release which was dependent on the presence of Ca2+. Verapamil, which blocks Ca2+ influx in excitable tissues, decreased potassium-induced release of 5-HT. Tritium release induced by ionophore X-537A was not dependent on extracellular Ca2+ while that induced by A-23187 required Ca2+. Cyclic-AMP, dibutyryl cyclic-AMP and theophylline did not significantly stimulate 5-HT release either in the presence or absence of Ca2+.
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The action of two types of ascorbate-related reductones on nucleic acids was investigated by comparison with that of ascorbic acid (AsA). Amino reductone (ScA) and thiol reductone (MHC) caused strandscissions in nucleic acids. This was confirmed by the fact that reductones lowered the viscosity of DNA solution and shifted the peaks of DNA and RNA to the low molecular side in centrifugal profile. Cu2+ strengthened their action as in the case of enediol reductones. The braking activity of thiol reductone is relatively wesk compared with those of amino and enediol reductones. The preferential degradation of spurinic acid was caused with amino and thiol reductones, suggesting that pyrimidine clusters in nucleic acids were susceptible to breakage.
The behavioral preference of mice for various ambient temperatures was investigated while the mice were housed in a wire mesh cage. The animals exhibited a significant avoidance of ambient temperatures of 22 degree C and lower, especially when they were in an inactive period. This result suggested that temperatures a little higher than those conventionally adopted might be appropriate for rearing mice in wire mesh cages.
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Lofepramine, (N-methyl-N-[4-chlorobenzoylmethyl]-3-[10,11-dihydro-5H-dibenz(b,f)-azepin-5-yl]-propylamine hydrochloride), is a new antidepressant with low toxicity and no peripheral anticholinergic activity. Its effect on 5-hydroxytryptamine (5-HT) and noradrenaline uptake into rat brain monoaminergic neurons was studied and compared with that of other antidepressants, particularly with that of imipramine and desipramine. Lofepramine inhibited both 5-HT and noradrenaline uptake into synaptosomal fractions in vitro but was 4 times more potent in inhibiting noradrenaline than 5-HT uptake, indicating the effect resembles that of desipramine. Noradrenaline uptake was also preferentially inhibited in synaptosomes from brain of rats treated previously with lofepramine or desipramine (i.p.). Pretreatment with SKF 525A (i.p.) did not diminish the effect of lofepramine, but rather potentiated it. Therefore it is suggested that the formation of desipramine is not necessary for lofepramine to exhibit, the effect on amine uptake in vivo. Both lofepramine and desipramine inhibited intraventricular noradrenaline uptake into synaptosomes without any effect on 5-HT uptake. These results suggest that lofepramine is qualitatively similar to desipramine with respect to preferential inhibition of noradrenaline uptake into central noradrenergic neurons.
Experiments were conducted with eight female mice on the avoidance of heat stress over the ambient temperature range from 25 to 34 degrees C. Significant avoidance behavior of the animals was observed at Ta = 30 degrees C, becoming more noticeable as the ambient temperature was raised. When exposed to heat, the animals showed peaks of avoidance during the second half of the dark period. This result seemed closely related to the spontaneous activity pattern of mice which reached a maximum between 1800 and 2000 at each experimental temperature. In this experiment, mice were more apt to choose a comfortable place during their inactive period than during their active period. This hypothesis on the relation between mice's heat avoidance and spontaneous activity was supported by the results of an additional experiment conducted in a cold environment of Ta = 18 degrees C.
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Some laboratory examinations were made with clindamycin-2-phosphate (CLDM-2-phos.). The drug was applied clinically to several otorhinolaryngological infections and the good results were obtained as follows. 1) Observing by biophotometer, the growth of Staphbylococcus aureus FDA 209P was inhibited well by the serum (diluted 10-fold) 30 minutes, 1, 2, 4 hours after 300 mg of CLDM-2-PHOS. were injected intramuscularly. 2) Serum concentration was determined by thin-layer method with Sarcina lutea ATCC 9341 as the test organism. The peak of serum level was obtained at 1 hour after a single intramuscular injection of 5 mg/kg or 10 mg/kg dosis of CLDM-2-phosphate. The peak of blood concentration was 5.4 mug/ml, 5.6 mug/ml respectively. 3) CLDM-2-phosphate concentration in tissues was estimated one hour after intramuscular injection of CLDM-2-Phosphate. The concentrations in blood and palatine tonsilla were 5.0 mug/ml and 2.9 mug/ml respectively after the intramuscular injection of 10 mg/kg. The concentrations in blood and mucous membrane of maxillar sinusitis were 4.1 mug/ml and 2.5 mug/ml respectively after the intramuscular injection of 10 mg/kg. 4) CLDM-2-phosphate was administered by intramuscular injection into 30 cases with various infections in otorhinolaryngological field. The clinical results were excellent in 22 cases (73.3%), effective in 3 cases (10.0%) and ineffective in 5 cases (16.7%). The effectiveness was 83.3%. 5) No side effects were observed in 30 cases.
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