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Biomedical subjects

K Ota

Publications and source records attributed to K Ota.

At least 793 records · Page 44Linked to original sources
PubMed1976

Duration of diestrous period and secretion of progestins during prolonged lactation in the rat.

The duration of the diestrous period in vaginal smears and the levels of progestins in ovarian venous blood were investigated in rats whose lactation period was prolonged by replacing pups at appropriate intervals. In prolonged lactating rats, the first diestrous period after the pospartum ovulation (21.7 +/- 0.8 days) was similar to that occurring in normal lactating rats. Subsequently proestrous or estrous vaginal smears reappeared at intervals during prolonged lactation. A total of 19 rats were studied during this period of prolonged lactation and 44 diestrous periods were observed. Forty-eight % of these periods ranged in length from 11 to 16 days (mean of 12.7). Very short diestrous periods lasting less than 3 days were observed 25% of the time. Diestrous periods lasting more than 17 days were observed only infrequently (7%). Progesterone concentration in the ovarian vein during the 2nd diestrous period reached a peak 4 days after the 1st estrus and the level was maintained until 11 days after the 1st estrus. The level of 20alpha-hydroxypregn-4-en-3-one remained fairly constant throughout the 2nd diestrous period.

Animals↗
PubMed1976

Is hollow fibre occlusion due to maldistribution of blood?

Blood flow has been shown to be very slow in the central portion of a capillary bundle where intracapillary clotting mainly occurs. It is concluded that extremely uneven blood distribution is a causative factor in intracapillary clot formation in the HFAK examined.

Blood Coagulation↗
PubMed1976

The influence of hyperbaric oxygenation on rat testes.

Using Wistar stain male rats, it has been shown that 2 atmospheric pressures associated with oxygen saturation, together or singly for 90 minutes daily for successive 46 days, resulted in no significant change on the ratio of testes to body weight. No significant change was observed in the incorporation of 3H-thymidine into testes and pituitary glands between the pressure-treated groups and the control group.

Animals↗
PubMed1975

The basis of the alkalophilic property of a species of bacillus.

An alkalophilic bacterium belonging to the genus Bacillus was isolated from an indigo ball. The bacterium exhibited a maximum growth rate at pH 10-0 TO 10-5. The incorporation of 14C-labelled amino acids or [14C]uracil, uptake of 14C-labelled alpha-amino isobutyric acid into the bacterium and oxygen consumption of the bacterium with amino acids as substrates were all maximum at pH 9-0 to 10-5. The uptake of [U-14C]glucose into the organism and oxygen consumption with carbohydrates, on the other hand, showed little variation of rate in the pH 8 to 10 region. The oxygen consumption of intact bacteria or protoplasts in culture medium was maximum at pH 10. The membrane of the bacterium oxidized NADH maximally at pH 7-5, and ATPase bound to the membrane exhibited maximum activity at pH 7.L-Lactate, L-alanine and malate dehydrogenases in the soluble fraction exhibited maximum activities at pH 7-4 to 8-4. The alkalophilic property of the bacterium may be due to the behaviour of the membrane towards charged substances admitted into the organisms.

Adenosine Triphosphatases↗
PubMed1975

Suppression of progesterone secretion in lactating rats by administration of ergocornine and the effect of prolactin replacement.

In order to assess the stimulatory effect of prolactin on the secretion of progesterone from corpora lutea in lactating rats, ergocornine meleate (ECO; 1 mg/day), an inhibitor of prolactin secretion, was administered subcutaneously on days 6 and 7 of lactation in primiparous rats. By day 8 of lactation, the concentration of progesterone in ovarian venous blood fell to a undetectable level in the ECO-treated animals, while the concentration in the control animals was very high at this stage of lactation. The level of 20-alpha-hydroxypregn-4-en-3-one was significantly higher on day 8 of lactation in ECO-treated than in control rats. Lactational dioestrus was interrupted by treatment with ECO and vaginal oestrus appeared 3-4 days after the start of treatment. Administration of ECO caused deleterious depression of milk production and of food intake of mother rats. In the pair-fed control animals, lactation continued almost normally throughout the experimental period. Prolactin (1 mg/day) administered simultaneously with ECO increased progesterone to levels even higher than those in control rats and restored 20-alpha-hydroxypregn-4-en-3-oen levels to those of the controls. The effect of the drug on milk production was alleviated. The results strongly suggest that prolactin is the most important factor in maintaining the function of corpora lutea in the lactating rats.

20-alpha-Dihydroprogesterone↗