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Biomedical subjects

Y Yoshimura

Publications and source records attributed to Y Yoshimura.

At least 487 records · Page 27Linked to original sources
PubMed1988

Effects of prostacyclin on ovulation and microvasculature of the in vitro perfused rabbit ovary.

Prostacyclin (prostaglandin I2) methyl ester at 0.1, 1, or 10 micrograms/ml was added to the perfusate of one rabbit ovary every 2 hours for the first 10 hours of perfusion. The contralateral ovary was perfused with medium alone. Prostacyclin methyl ester at 1 and 10 micrograms/ml induced ovulation in the absence of gonadotropin, with ovulatory efficiencies of 26.7% +/- 3.8% and 46.5% +/- 5.0%, respectively. Most ovulated ova (77.4%) did not progress beyond the germinal vesicle stage, and there was no significant degeneration of ovulated ova or follicular oocytes. Examination of the follicular microvasculature 5 hours after exposure to prostacyclin revealed marked vessel dilatation and filling defects at the apex. By 7 hours after prostacyclin exposure, the intrafollicular space contained extravasated resin, reflecting increased vascular permeability. The vascular changes paralleled those previously observed in gonadotropin-induced ovulation. These results indicate that prostacyclin acting locally alters the vascular integrity of the follicle wall and facilitates follicle rupture.

Animals↗
PubMed1988

Scintigraphic evaluation of the salivary glands in patients with Sjögren's syndrome.

The clinical value of salivary gland scintigraphy (RI-sialography) was studied in 11 cases with definite Sjögren's syndrome. Time-activity curves which were obtained from computer-assisted analysis of RI-sialography were classified into 4 types (N:normal type, M:median type, F:flat type, S:sloped type), and the efficacy of scintigraphy in evaluating salivary gland function and the relationship between time-activity curves and other diagnostic methods are discussed. Flattened time-activity curves such as F- or S-type were more often seen in submandibular glands than in parotid glands. Flattened curves were not seen in the early stage of the inflammatory process; conversely, when we found a flattened curve, it suggested a wide destruction of the salivary gland tissues. Correlation between time-activity curve and sialography showed 90.9%, and correlation between time-activity curve and histopathological change in the minor salivary gland of the lower lip also showed 90.9%.

Adult↗
PubMed1988

Squamous cell carcinoma antigen in the serum of oromaxillary cancer.

Squamous cell carcinoma (SCC) antigen levels in sera and several tissues were estimated in patients with oral and maxillary cancer. The normal value of serum SCC antigen level was 1.7 ng/ml in this experiment, and 43.3% of squamous cell carcinoma was positively higher than 1.7 ng/ml as a whole, including cases of carcinoma in situ and of recurrence and metastasis in the oral region. In relation to the clinical staging of tumors, 20.0% in stage I, 14.3% in stage II, 42.9% in stage III, and 77.8% in stage IV were positive for SCC antigen. In the group with definite regional lymph node metastases, 80% of patients revealed a higher value than the normal cut-off value. Patients with recurrent SCC demonstrated elevated SCC antigen values in sera except 1 case with an early condition of recurrence. Serum SCC antigen also presented good responses to various cancer treatments. The measurement of SCC antigen does not appear to be useful for the detection of early stage oral and maxillary SCC; however, for detection of recurrence and for lymphatic and/or remote metastases in the follow-up period, it would appear that SCC antigen level would be some value.

Adult↗
PubMed1988

ADP-ribosylation of bradykinin and effects on its biological activities.

We investigated the ADP-ribosylation of bradykinin by hen liver nuclear ADP-ribosyltransferase. Two Arg residues of the peptide were modified by this enzyme. Arg1 was preferentially modified as compared to Arg9; the Vmax/Km for Arg1 was 3 times higher than that for Arg9. These results were given support by data observed in experiments with des-Arg1 and des-Arg9 bradykinin; the Vmax/Km for des-Arg9 bradykinin was 3 times that for des-Arg1 bradykinin. ADP-ribosylation suppressed the biological activity of bradykinin, as related to both binding and contractile activities. The extent of ADP-ribosylation-induced suppression of both activities was higher in the case of the modification of Arg1 than that of Arg9. In view of the observation of ADP-ribosyltransferase activity in skeletal, cardiac, and smooth muscles (Soman, G. et al. (1984) Biochem. Biophys. Res. Commun. 120, 973-980; Shimoyama, M. et al. (1987) in The 8th International Symposium on ADP-Ribosylation, Texas, abstract p. 13), bradykinin functioning in the contraction of smooth muscle may be modified in this way in vivo.

ADP Ribose Transferases↗
PubMed1988

Quantitative light microscopic analysis of corpus luteum growth during pseudopregnancy in the rabbit.

We employed stereological methods at the light-microscope level to examine the mechanism by which corpora lutea (CL) grow during the course of pseudopregnancy in the rabbit. Corpus luteum volume per ovary, the absolute volume of luteal cells per CL, individual luteal cell volume, the number of luteal and endothelial cells per CL, and capillary surface area per CL were examined in rabbits at Days 1, 4, 7, 11, and 18 of pseudopregnancy. Total CL volume increased from 3.7 +/- 0.1 microliter to 30.3 +/- 0.5 microliter over Days 1 to 11 and thereafter decreased to 15.2 +/- 1.1 microliter by Day 18. Stereological analyses showed that the increases in CL volume from Day 1 to Day 11 were due primarily to increases in the volume of individual luteal cells (from 2.6 +/- 0.2 pl on Day 1 to 23.5 +/- 1.7 pl on Day 11, 1 pl = (10 mu)3; r = 0.96), and that the decrease in CL volume after Day 11 resulted largely from a decrease in luteal cell volume (to 12.8 +/- 1.5 pl). In contrast, no change was seen in the number of luteal cells per CL (range 9.1 x 10(5)-12.5 x 10(5)). These data show that CL growth and subsequent regression during pseudopregnancy result primarily from changes in the volume of individual luteal cells, and not from changes in the number of luteal cells. These data support the hypothesis that modulation of progesterone production during pseudopregnancy is due to changes in individual luteal cell volume and not to changes in cell number.

Animals↗
PubMed1988

Progesterone secretion by corpora lutea of the isolated perfused rabbit ovary during pseudopregnancy.

An ovarian in vitro perfusion method was adapted to examine rabbit corpus luteum (CL) function during pseudopregnancy. Ovaries were perfused in vitro with tissue culture Medium 199 with or without 3% bovine serum albumin (BSA). Samples were obtained from both arterial and venous cannulae, allowing rates of progesterone secretion to be determined. Two perfusion methods were compared: a closed system in which perfusion medium continuously recirculated through the tissue, and an open system in which the ovarian vein cannula was left outside the perfusion chamber. The addition of 3% BSA was found to prevent edema and distortion of the interstitial space, and to result in increased progesterone secretion. With the closed perfusion system, the progesterone secretion rate measured over the 6-h perfusion was significantly higher on Day 11 than on Day 1 of pseudopregnancy and had declined significantly on Day 18. There was no difference in secretion rates whether the perfusion system was open or closed, and the results obtained with both systems closely approximated in vivo progesterone secretion rates. Measurements of CL tissue progesterone content before and after in vitro perfusion indicated that the changes in progesterone secretion seen during pseudopregnancy resulted from differences in the synthesis and secretion of progesterone and not from leakage of progesterone already present in the CL prior to perfusion. Taken together, these results indicate that the modified in vitro perfused rabbit ovary preparation described herein is an appropriate model to examine progesterone secretion by ovaries bearing CL.

Animals↗
PubMed1988

Treatment of polycystic ovarian disease by inducing ovulation with pulsatile subcutaneous administration of human menopausal gonadotrophin associated with luteinizing hormone-releasing hormone analogue.

Treatment with a combination of luteinizing hormone-releasing analogue (GnRHa, Buserelin) and pulsatile administration of hMG (Group I) were used to induce ovulation in nine patients with polycystic ovary syndrome (PCO). The same patients were also treated with pulsatile hMG administration alone (Group II). Ovulation was observed in all twelve treatment cycles in Group I, and there were two pregnancies. In Group II, ovulation occurred in 22 of 26 treatment cycles. Ovarian hyperstimulation occurred in one cycle of Group I and in 5 of 26 cycles of Group II. The total dose per cycle of hMG to induce ovulation in Group I was significantly lower than that needed when only pulsatile hMG administration was used. In response to Buserelin administration, the concentrations of serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) increased transiently and then declined to the normal range observed in the early follicular phase. The concentrations of FSH increased in response to hMG administration, resulting in a normal LH/FSH ratio. The present data demonstrated that pulsatile subcutaneous administration of hMG in addition to Buserelin was effective in inducing follicular maturation and ovulation in patients with PCO with a lower incidence of serious side-effects.

Adult↗
PubMed1988

An appropriate model for congenital hypothyroidism in the rat induced by neonatal treatment with propylthiouracil and surgical thyroidectomy: studies on learning ability and biochemical parameters.

Hypothyroidism was induced in rats by treatment with propylthiouracil through the mother's milk throughout the suckling period followed by surgical thyroidectomy without use of radioiodine. The growth of these animals was considerably retarded and their light-dark discriminative operant learning ability was also significantly decreased. Replacement therapy with thyroxine to maintain its normal serum concentration was effective for continuing normal growth and development of learning ability. Therefore, these hypothyroid rats are a useful model of congenital hypothyroidism. Biochemical studies showed that the inhibition of cerebral Na,K-ATPase and succinic dehydrogenase activities detected in early postnatal life in these hypothyroid rats was transient and that normal activities of these enzymes were later regained in adult rats. However, the activity of 2',3'-cyclic nucleotide 3'-phosphohydrolase and the brain myelin remained low throughout life unless thyroxine was administered. Though a critical correlation between biochemical parameters and learning ability is still uncertain, these results suggest that the formation of myelin in the neonatal period is at least dependent on thyroid hormone and would play an important role in mental development.

Animals↗
PubMed1988

The effects of bradykinin on ovulation and prostaglandin production by the perfused rabbit ovary.

Involvement of the vasoactive peptide bradykinin (BK) in ovulation, oocyte maturation, and prostaglandin (PG) production was assessed using an in vitro perfused rabbit ovary preparation. In the first experiment, BK at a concentration of 0.033, 0.33, or 3.3 micrograms/ml was added to the perfusate of one ovary at hourly intervals for the first 10 h of perfusion. The contralateral control ovary was treated with medium alone parallel to the experimental ovary. Ovaries were perfused for a total of 12 h. BK induced ovulation in the absence of gonadotropin in a dose-related fashion, but did not induce maturation of ovulated ova or follicular oocytes. BK significantly stimulated PG production at all concentrations tested, but the effect was not dose related. Prostacyclin, as reflected by the concentration of 6-keto-PGF1 alpha in the perfusate, was the major PG produced. Smaller quantities of PGE2 and PGF2 alpha were present in the perfusate. After a single injection of BK (3.3 micrograms/ml), 6-keto-PGF1 alpha and PGF2 alpha production increased within 15 min and reached a maximum at 60-90 min. PGE2 did not change significantly over this time period. The addition of 1 microgram/ml indomethacin to the perfusate completely inhibited BK-stimulated PG production. However, indomethacin did not significantly affect the ovulatory efficiency of BK-treated ovaries. Neither BK nor indomethacin induced any degenerative changes in ovulated ova or follicular oocytes. The addition of a BK antagonist at 1 microgram/ml every 30 min to the perfusate resulted in an effective blockade of hCG-induced ovulation. These results suggest that BK is involved in the process of follicle rupture, but BK may induce ovulation by a mechanism(s) other than through PG stimulation.

6-Ketoprostaglandin F1 alpha↗
PubMed1988

The effects of oxygen toxicity on the pregnant rat using an apparatus designed to measure oxygen consumption method.

To evaluate the effects of oxygen toxicity in the pregnant rat at high and low concentrations of oxygen, an oxygen-consumption apparatus was devised to measure the consumption of oxygen continuously over long periods. Oxygen consumption, partial oxygen pressure on the skin (tcPo2), and lipid peroxide levels in the serum were measured. There was a close correlation between oxygen consumption and body weight of rats that weighed between 150 g and 450 g. Oxygen consumption during the later stages of pregnancy increased by 1.8 ml/day, an increase of 8%. Oxygen consumption by rats during parturition increased markedly for up to 1 h and then reached and remained at a plateau value until the end of delivery. Exposure of pregnant rats to low concentrations of oxygen resulted in a marked depression in oxygen consumption and tcPo2 during the exposure time. A significant increase in the lipid peroxide level in serum was observed in the mother rat after birth and in the newborn offspring of pregnant rats exposed to 16% oxygen for 3 h.

Animals↗
PubMed1988

Effects of gonadotrophins, steroid hormones, and epidermal growth factor on the in vitro proliferation of chicken granulosa cells.

Effects of gonadotrophins, steroid hormones, and epidermal growth factor (EGF) on the in vitro proliferation of granulosa cells obtained from the second largest follicles of laying hens were examined. It was observed that follicle-stimulating hormone and luteinizing hormone as well as EGF significantly promoted proliferation of these cells, unlike estradiol and progesterone. These results suggest that gonadotrophins as well as certain growth factors may be involved in proliferation of chicken granulosa cells.

Animals↗
PubMed1988

NMR studies of chromomycins, olivomycins, and their derivatives.

Detailed studies on the 13C and 1H NMR spectra of chromomycins A2 and A3, olivomycins A and B, and their derivatives clarified the assignment of many signals which had been unassigned or erroneously reported in the literatures. The revised assignments for chromomycin A3 and olivomycin A include the assignment of a key 13C signal used to discuss the saccharide linkage in question. Structure analyses based on the revised assignments support the alpha,1----3-bond between components of the disaccharide moiety in the molecules. Some general information useful for structure analysis of saccharides is also reported.

Chromomycins↗
PubMed1988

Effect of the exposure of intrafollicular oocytes to clomiphene citrate on pregnancy outcome in the rabbit.

This study was designed to determine if exposure of rabbit intrafollicular oocytes to clomiphene citrate (CC) affects pregnancy outcome after in vitro ovulation, in vitro fertilization (IVF), and embryo transfer (ET). Ovaries were perfused in the presence or absence of CC (10(-5) M) and estradiol (E2, 100 ng/ml). Human chorionic gonadotropin (hCG, 50 IU) was added to the perfusate of all ovaries. In vitro ovulated ova were retrieved, inseminated, and transferred to host rabbits. Neither CC nor CC + E2 significantly affected hCG-induced ovulation or fertilization. CC significantly reduced (P less than 0.025) percentage of ovulated ova resulting in offspring. Addition of E2 significantly (P less than 0.05) reversed the reduction in offspring associated with CC alone. These results may be due to the antiestrogenic effects of CC on the intrafollicular oocyte, which compromises postfertilization development.

Animals↗