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Biomedical subjects

M Takeuchi

Publications and source records attributed to M Takeuchi.

At least 901 records · Page 50Linked to original sources
PubMed1984

A new method for inducing copious drinking and the accompanying stimulation on the pars intermedia of the mouse pituitary gland.

A new method for causing excessive liquid intake was developed as the condition opposite to dehydration, and the effect of this copious drinking for 2, 4 and 6 days on the pars intermedia of the hypophysis was evaluated by quantitative electron microscopy in mice. Free access to 5% glucose solution and concurrent food deprivation resulted in the development of polydipsic mice. Drinking volume was 18.9 +/- 1.1 ml/10 g BW on day 2, 20.8 +/- 1.2 on day 4 and 24.1 +/- 1.3 on day 6, respectively, while remaining at 2.2 +/- 0.2 ml/10g BW in the control. Copious drinking was found to elicit secretory activity of the pars intermedia cells. The cytoplasmic volume percentage of rough endoplasmic reticulum (rER) and the numerical density of Golgi granules increased significantly on day 2 reaching a peak on day 4. Contrarily, secretory granules decreased in number, indicating that the granule release exceeded the activated granule formation. The rise in the activity of the gland was followed by a slight fall after 6 days, which was probably due to a malnutritional condition by food deprivation. Neither 20% glucose drinking nor food deprivation for 4 days enhanced the pars intermedia cells. Thus, excessive water intake seems to be a plausible reason for stimulating secretory activity in cells of the pars intermedia of the hypophysis in mice.

Animals↗
PubMed1984

[Chronic toxicity study of AC-1370 sodium, an antibiotics, intravenously administered in rats].

A study on chronic toxicity of AC-1370 sodium (AC) in addition to recovery from its toxicity, was carried out using the rat. AC was administered to the rat through the tail vein in doses of 30, 100, 300 and 1000 mg/kg body weight/day, with the periods for administration and recovery being 26 and 13 weeks, respectively. The results obtained from the present study were as follows. In each group, neither death case nor fatal damage was observed throughout the whole process. In the group of 1000 mg/kg, the below findings were observed in one or both sexes: suppression in increase of body weight, increases in drunk amount of water, urinary volume and urinary excretions of electrolytes, degeneration in renal tubules and several correlated changes, tendency of anemia, changes in serum biochemical tests, and changes in each organ weight. In the group of 300 mg/kg, the above findings were observed slightly in comparison to the group of 1000 mg/kg. In the groups of 100 and 30 mg/kg, any changes suggesting the damages were not observed. In the recovery test, the group of 1000 mg/kg was found to be incompletely restored from the damages, with the partially residual damages being shown. In contrast, the group of 300 mg/kg showed to be almost restored from the damages. These results denotes that the maximal non-toxic dose of AC in this study is 100 mg/kg/day in long-term administration.

Animals↗
PubMed1984

[Effects of intravenous administration of ranitidine hydrochloride on the fertility of the male and female rats].

The effects of ranitidine hydrochloride, a histamine H2-receptor antagonist, on the reproductivity of male and female rats of Crj:CD (SD) strain and the development of their fetuses were examined. Ranitidine hydrochloride was intravenously administered once daily at dose levels of 5, 15 and 40 mg/kg in base weight respectively, to males from 60 days before mating until the completion of mating, and to females from 14 days before mating up to day 7 of gestation. All pregnant females were killed on day 20 of gestation and their fetuses were examined morphologically. Tachypnea, prone position and transient tremor were observed for a short period of time directly after an intravenous administration of ranitidine in the dose of 40 mg/kg, which were probably induced by a rapid fall in blood pressure. There was a significant decrease in the weight of spleen in males of 15 and 40 mg/kg groups. Treatment with ranitidine hydrochloride did not have any influence on mating performances and pregnancy at all dose levels. In observation of the fetuses, there was no influence of ranitidine hydrochloride administration on fetal growth and development. A few external, skeletal and visceral malformations were seen sporadically in each group, and 19 cases of dwarf fetuses were observed in 2 dams of 40 mg/kg group, but these changes were not attributable to administration of the drug. These results indicated that ranitidine hydrochloride intravenously administered to males and females before mating and to pregnant females in early stages of gestation had no toxic effects on reproductivity in either sex at the dose of 40 mg/kg/day or less.

Abnormalities, Drug-Induced↗
PubMed1984

[Effects of intravenous administration of ranitidine hydrochloride to the pregnant rat in organogenesis period].

The effects of ranitidine hydrochloride, a histamine H2-receptor antagonist, on development and general behavior of F1 generation of Crj: CD (SD) rats were examined. Ranitidine hydrochloride was intravenously administered once daily from day 7 to 17 of gestation at dose levels of 5, 15 and 40 mg/kg in base weight respectively. Two-thirds of females were killed on day 20 of gestation to examine the development of fetuses, the remaining females were allowed to litter naturally and the postnatal development of the offsprings was observed. Tachypnea, prone position and transient tremor were observed for approximately 15 from 30 seconds directly after an intravenous administration of ranitidine hydrochloride in the dose of 40 mg/kg, which were probably induced by a rapid fall in blood pressure. During the gestation period, there occurred a slight depression of the maternal body weight gain in the ranitidine-treated groups. At the stage of lactation, the body weights of dams showed slightly lower levels than control and their liver weights of dams were also inclined to decrease in 15 and 40 mg/kg groups. In the observation of the fetuses, there were no significant differences between the control and ranitidine-treated groups concerning fetal growth and development, external, skeletal and internal anomalies in fetuses. In delivery and postpartum observation, no influence of ranitidine administration was observed on the litter size, mortality rate of F1 pups. There was a tendency towards decrease in body weight in males of the ranitidine-treated groups. But no significant changes were observed in general behavior, postnatal development, various functions such as reflex response, learning and reproductive performances of F1 generation. Therefore, it was concluded that ranitidine hydrochloride had no effects on fetal and postnatal development, general behavior and various functions of F1 generation at the dose of 40 mg/kg/day or less.

Abnormalities, Drug-Induced↗
PubMed1984

[Effects of intravenous administration of ranitidine hydrochloride to the female rat in perinatal and postnatal periods].

The effects of ranitidine hydrochloride, a histamine H2-receptor antagonist, on delivery, lactation, postnatal development of F1 generation of Crj:CD (SD) rats were examined. Ranitidine hydrochloride was intravenously administered once daily from day 17 of gestation to day 21 after delivery at dose levels of 5, 15 and 40 mg/kg in base weight respectively. All females were allowed to litter naturally, and postnatal development of offsprings was observed. Tachypnea, prone position and transient tremor were observed for approximately one minute directly after an intravenous administration of ranitidine in the dose of 40 mg/kg, which were probably induced by a rapid fall in blood pressure. In delivery and postpartum observation, there occurred no influence of the ranitidine administration on maternal body weight, delivery and lactation. In studies on general behavior of F1 rats, no abnormal changes were observed on postnatal development and various functions such as reflex response and learning. Ranitidine treatment did not affect reproductive performances of F1 generation. A slight inhibition in body weight gain and a slight decrease in average weight of liver were observed in F1 females of 40 mg/kg group, but no other influence attributable to the ranitidine administration was observed on the general state and development of offsprings. In necropsy of offsprings, hydronephrosis, transitional epithelial carcinoma, kinky tail, unilateral absence of testis and epididymis were observed in one case of ranitidine-treated groups. But they were not attributable to administration of ranitidine. In summary, it was concluded that ranitidine hydrochloride had no effects on delivery and lactation of dams, and also on viability, development and various functions of F1 generation at the dose of 40 mg/kg/day or less.

Animals↗
PubMed1984

[A study of neonatal behavioral characteristics: The relationship between Brazelton Neonatal Behavioral Assessment Scale and infant-perception by nurses].

The purpose of this study was to measure the behavioral characteristics of neonates and to investigate the relationship between these characteristics and infant-perception by adults (nurse). Brazelton Neonatal Behavioral Assessment Scale (BNBAS) were administered to 45 neonates three or four days after birth. Nurses were required to assess the perception of the neonates who received BNBAS during two to five days after birth. The main findings were as follows: A factor analysis was performed on the behavioral items of BNBAS, and six factors corresponding to Osofsky's factors (1977) were extracted. As for the behavioral items, there was no significant sex differences. Some of BNBAS factors related to the infant-perception by nurses.

Female↗
PubMed1984

Valiolamine, a new alpha-glucosidase inhibiting aminocyclitol produced by Streptomyces hygroscopicus.

Valiolamine, a new aminocyclitol has been isolated from the fermentation broth of Streptomyces hygroscopicus subsp. limoneus and its structure has been determined to be (1(OH),2,4,5/1,3)-5-amino-1-C-(hydroxymethyl)-1,2,3,4-cyclohexanetetr ol. Valiolamine has more potent alpha-glucosidase inhibitory activity against porcine intestinal sucrase, maltase and isomaltase than valienamine, validamine and hydroxyvalidamine which were reported as building blocks of validamycins and microbial oligosaccharide alpha-glucosidase inhibitors. In addition, valienamine, validamine and hydroxyvalidamine have been isolated from the fermentation broth.

Chemical Phenomena↗
PubMed1984

An in vitro screening method for antitumor and/or antitumorigenic substances involving the transformation of chick embryo fibroblasts infected with Rous sarcoma virus.

An efficient in vitro screening method for antitumor and/or antitumorigenic substances was established. The method is based on determining inhibitory effect of a compound on an RSV-induced tumorigenic process and the growth of the established tumor cells in a single assay system in the presence of normal cells. These effects were determined by inhibition of focus formation in a culture of chick embryo fibroblasts, while the nonspecific cytotoxic effect was determined by inhibition of the protein content of the same culture. The efficiency of this method in screening drugs was confirmed by testing various clinical and preclinical compounds.

Animals↗
PubMed1984

Microbial degradation of validamycin A by Flavobacterium saccharophilum. Enzymatic cleavage of C-N linkage in validoxylamine A.

The enzymatic cleavage of C-N linkage in the degradation of validamycin A by Flavobacterium saccharophilum was examined using N-p-nitrophenyl derivatives of validamine and valienamine as synthetic model substrates for validoxylamine A. Incubation of N-p-nitrophenylvalidamine with the membrane fraction from the organism led to formation of N-p-nitrophenyl-3-ketovalidamine, and succeeding cleavage of C-N linkage. As the products of the cleavage step, one was identified as p-nitroaniline and another keto compound could not be purified enough because of its instability. However, on the basis of its hydrogenation products, the structure of the keto compound could be established as 5D-(5/6)-5-C-(hydroxy-methyl)-2,6-dihydroxy-2-cyclohexen-1-one. The same experiment was carried out with N-p-nitrophenylvalienamine. In this case, N-p-nitrophenyl-3-ketovalienamine could be isolated as an intermediate but the desired keto compound from the cleavage step could not be isolated because of its instability. The participation of two enzymes, that is, a dehydrogenase and a C-N lyase on the cleavage of C-N linkage was assured, and moreover, the analysis of its products, together with those of the previous studies allow us to propose a degradation pathway of validamycin A by Flavobacterium saccharophilum.

Flavobacterium↗