Biomedical subjects

Osamu Tokuyama

Publications and source records attributed to Osamu Tokuyama.

7 recordsLinked to original sources

PubMed2006

Insulin-lowering agents inhibit synthesis of testosterone in ovaries of DHEA-induced PCOS rats.

BACKGROUND: Insulin-lowering agents are reported to be useful in treating polycystic ovary syndrome (PCOS) anovulation. It has been suggested that lower insulin levels secondarily affect ovarian tissue, although the direct mechanism of action has not yet been verified. Here we investigated if these agents directly affect the ovary. METHODS: Thirty female Wister rats were studied. Six control rats were injected subcutaneously with 0.2 ml sesame oil, while 24 rats used as PCOS models were injected subcutaneously with dehydroepiandrosterone (DHEA) and divided into four groups. Six rats were injected with only DHEA, while the remaining 18 rats received metformin, pioglitazone or troglitazone. The ovaries were immunohistochemically stained with anti- testosterone and anti-17beta-HSD antibodies, and then evaluated for morphological changes. RESULTS: In the DHEA administration group, the number of atretic follicles significantly increased compared to that of control rats. The insulin-lowering agents did not improve the multicystic appearance. Serum testosterone concentrations significantly increased with DHEA administration, but the increase was inhibited by oral administration of insulin-lowering agents. Testosterone deposits in ovarian tissue were also reduced by feeding rats insulin-lowering agents. CONCLUSION: Insulin-lowering agents affected ovarian tissue by inhibiting testosterone biosynthesis in vivo.

17-Hydroxysteroid Dehydrogenases↗

PubMed2005

[A case of complex endometrial hyperplasia with atypia treated by microwave endometrial ablation].

Complex endometrial hyperplasia with atypia (CEHA) often precedes an endometrial carcinoma. A nulli-gradiva woman at high risk due to various complications underwent microwave endometrial ablation (MEA) at a frequency of 2.45 GHz for treatment of CEHA as an alternative to hysterectomy. The endometrium near the internal orifice was conserved to avoid hematometra. Endometrial biopsy specimen from the neighborhood of the internal orifice did not show any signs of endometrial hyperplasia postoperatively. Two years after the operation, endometrial biopsy revealed recurrence. The second MEA was performed. MRI one month after the second operation revealed that the uterine lining was completely replaced by avascular area without signs of regrowing endometrium or endocevix. Eighteen months have passed without recurrence.

Catheter Ablation↗

PubMed2003

Using a vortex mixer for testicular sperm collection.

OBJECTIVE: To evaluate 2 methods of processing testicular tissue for the retrieval of viable sperm from men with nonobstructive azoospermia. STUDY DESIGN: Fresh testicular tissue was obtained from nonobstructive azoospermia patients using a biopsy needle. The specimens were divided into 2 fractions. All specimens were minced and immersed in human tubal fluid (HTF). The first fraction was filtered through a nylon filter and incubated for 3 hours. The supernatant was centrifuged, resuspended in HTF and analyzed. The second fraction was immediately vortexed for 5 minutes and filtered through a nylon filter. The supernatant was centrifuged, resuspended in HTF and analyzed. RESULTS: Spermatozoa were obtained in 13 of 24 cases (54.2%) using the vortex method and in 5 of 24 cases (20.8%) with the nylon filter method. CONCLUSION: The vortex mixing method may be a better option than the conventional method for processing testicular tissue for sperm collection.

Adult↗

PubMed2003

Expression and distribution of cyclooxygenase-2 in human ovary during follicular development.

Prostaglandins play important roles for oocyte maturation and follicular rupture. Cyclooxygenase-2 (COX-2), an inducible isoform of a prostaglandin metabolic enzyme, is essential for the timed production of prostaglandins in the ovary. The aim of the present study is to examine expression and distribution of COX-2 in human ovarian follicles at each of the maturation stages. Immunohistochemical staining shows that COX-2 is expressed in the granulosa cell layer of secondary and developing follicles, but is not detected in primary and Graafian follicles. Western blotting analysis revealed the existence of COX-2 in periovulatory follicular fluid at a mean concentration of 5.6 +/- 0.6 ng/ml. COX-2 might begin to be produced at the secondary follicle stage, and once a follicle reaches the Graafian follicle stage, the production of this enzyme is stopped. After exposure to luteinizing hormone (LH) surge, follicles might resume production of COX-2, and this is secreted into the follicular fluid.

Adult↗

PubMed2002

Asymptomatic pelvic Castleman disease in an infertile woman: case report.

Castleman disease is defined as angiofollicular benign lymph node hyperplasia usually found in the mediastinum. Pelvic lymph node involvement is very rare. We now report a case of asymptomatic intrapelvic Castleman disease found by chance in an infertile woman. Transvaginal ultrasonography is very useful in diagnosing the disease. After 7 years of follow-up, the patient is free from recurrence.

Adult↗

PubMed2002

Vascular endothelial growth factor concentrations in follicular fluid obtained from IVF-ET patients: a comparison of hMG, clomiphene citrate, and natural cycle.

PURPOSE: Evaluation of vascular endothelial growth factor (VEGF) concentrations of follicular fluid (FF) in accordance with an ovarian stimulation protocol and ovarian response. METHODS: The subjects of this study were 38 patients undergoing IVF-ET in our hospital. They were divided into three groups according to ovarian stimulation protocols; Group 1: hMG cycles (n = 19), Group 2: clomiphene citrate cycles (n = 10), Group 3: natural cycles (n = 9). They reclassified into three groups according to the number of oocytes harvested. VEGF concentration was measured in FF, employing ELISAs. RESULTS: Group 1 shows lower VEGF concentrations in FF than Group 2 or Group 3. Excluding high responders from Group 1, no difference was found among these three groups. As for the reclassified groups, group of highest number of oocytes havested showed lowest VEGF concentrations in FF. CONCLUSIONS: VEGF concentrations in FF might negatively correlate with the number of follicles, irrespective of the ovulation induction protocol.

Adult↗

PubMed2002

Promotion of human blastocyst formation by red cell hemolysate.

Recently, blastocyst transfer has been increasingly performed to improve the implantation rate achieved by in vitro fertilization and embryo transfer. This has created the need for new culture methods to improve in vitro blastulation. Culture with erythrocyte hemolysate promotes the development of early mouse embryos due to an antioxidant effect. The present study investigated whether erythrocyte hemolysate could also promote blastulation of human embryos. Eighty surplus embryos were obtained from 15 patients who gave informed consent. These embryos were cultured for 2 to 7 days after oocyte retrieval in medium with or without erythrocyte hemolysate. Blastocyst formation was observed in 53% and 28% of the embryos grown in hemolysate-supplemented and control cultures, respectively. The blastulation rate was significantly higher in hemolysate-supplemented culture than in control group (p = 0.02). These results suggest that culture medium supplemented with erythrocyte hemolysate may promote the blastulation of human embryos.

Adult↗