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Biomedical subjects

Y Imamura

Publications and source records attributed to Y Imamura.

At least 433 records · Page 24Linked to original sources
PubMed1983

Activation and molecular weight changes of human plasma inactive renin by proteolytic enzymes.

By treating human plasma with trypsin (1 mg/ml), 3 different peaks of renin activity were detected by a gel filtration on Ultrogel AcA 44. The molecular weights of these activated renins were estimated to be 47,000, 45,000 and 43,000 daltons, respectively. 2) The molecular weight of human plasma active renin partially purified was 43,000 daltons. After treatment with neuraminidase, the molecular weight decreased to 38,000 daltons. 3) When the partially purified plasma inactive renin, which was completely separated from active renin, was activated by trypsin, chymotrypsin, plasmin, pepsin and renin, the activated renins had different molecular weights. The highest molecular weight form (47,000-48,000) was trypsin-activated or plasmin-activated renin and the lowest molecular weight form (38,000) was renin-activated renin. 4) These results suggest that cleavage of the specific site in peptide bond of plasma inactive renin by various proteolytic enzymes results in different molecular weights of activated renins. Plasma active renin free from sialic acid is very similar to kidney renin.

Chromatography, Gel↗
PubMed1982

[Uterine response to estrogen in the rat of hypothyroidism].

Hypothyroidism has been believed to affect the female reproductive system, but relatively few studies have been made on the direct effects of the thyroid hormone on the uterus, and the results have been conflicting. In the present paper, thymidine kinase (TK) and progesterone receptor (PrgR) in cytosol were assayed in the rat to study the uterine response to estrogen. Furthermore, this uterine response to estrogen was compared between hypothyroid and euthyroid rats. Hypothyroidism was induced by surgical operation performed at 21 days of age. Immature rats: Estradiol (E2) was injected on day 26. No significant difference in increases of uterine wet weight, TK and PrgR was noted between hypothyroid and euthyroid rats 30 h after E2 injection. Adult rats: Ovariectomy was added at 21 days or 65 days of age. E2 was injected on day 70. No significant difference in increases of uterine wet weight, TK and PrgR was noted between hypothyroid and euthyroid rats 24 h or 48 h after E2 injection. These results suggest that hypothyroidism may have no direct effects on such uterine responses to estrogen as wet weight, TK and PrgR.

Animals↗
PubMed1982

[Estrogen receptors of the rat uterus during pregnancy and lactation].

Uterine estrogen receptors (ER) of the rat during pregnancy and postpartal lactation were assayed. Both the cytoplasmic and nuclear ER were determined by the controlled pore glass (CPG) method as previously described in detail. The cytoplasmic ER level slightly decreased as pregnancy advanced and then increased remarkably during postpartal lactation, with a tendency to decrease at 5 weeks of lactation when the estrous cycle could have recurred despite the nursing behavior of the rats. On the other hand, no remarkable difference in nuclear ER was noted during pregnancy and lactation. A high concentration of plasma progesterone could have reduced the translocation of the cytoplasmic ER to the nucleus and the replenishment of the cytoplasmic ER, despite a high concentration of plasma estrogen during pregnancy. In order to keep an environment of a high plasma concentration of estrogen similar to that of pregnancy, a long-acting estrogen (estradiol dipropionate) was injected in to the proestrous rats. The cytoplasmic ER rapidly translocated to the nucleus, followed by a prolonged maintenance of a low cytoplasmic and a high nuclear ER level until 7 days, with a gradual replenishment of the cytoplasmic Er and a gradual decline of the nuclear ER thereafter. A translocation of the cytoplasmic Er to the nucleus, similarly seen in the hysterectonized-adult rats treated with estradiol, was noted in the rats injected with estradiol at 3 weeks of lactation. In general, low estrogen and high prolactin may be held in plasma during lactation. These results indicate that the fluctuation of uterine ER simply depends on the plasma level of estrogen during pregnancy and postpartal lactation in rats.

Animals↗
PubMed1982

Plasma lipids and lipoproteins in Japanese male patients with coronary artery disease and in their relatives.

Plasma cholesterol (CH), triglyceride (TG) and high density lipoprotein cholesterol (HDL-C) were measured in 92 consecutive Japanese male subjects undergoing diagnostic coronary cineangiography. Sixty-nine of them were classified as having coronary artery disease (CAD), the remaining 23 subjects were classified as having normal coronary arteries (NCA). The CAD group had significantly lower HDL-C and higher TG levels than the NCA group. However, there was no significant difference in plasma CH between the two groups. First-degree relatives of the CAD patients were also investigated. The male blood relatives of the CAD patients also had significantly lower HDL-C and higher TG levels than the non-blood male relatives and healthy control males. The female blood relatives, however, showed no significant differences from the non-blood female relatives and the healthy control females in plasma CH, TG and HDL-C levels. These results suggest that low HDL-C and hypertriglyceridemia are the prevalent coronary risk factors, rather than hypercholesterolemia, in a population with a low fat intake such as the Japanese, and that these lipid abnormalities are related to sex and genetic factors.

Adult↗