Hirofumi Kamiya

Kato Ladies Clinic, Edo, Tōkyō, Japan

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Publications (5)14.61 Total impact

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    ABSTRACT: Polycystic ovary syndrome (PCOS) is a heterogeneous group of disorders that occur fairly commonly in women of reproductive age and are characterized by a variety of clinical manifestations, including insulin resistance that is independent of obesity. Recent studies suggest that altered adipocytokine gene expression is closely associated with insulin resistance and that single nucleotide polymorphisms (SNPs) modulate the expression and/or function of these genes, thereby affecting insulin sensitivity. With that in mind, we investigated whether SNPs at position −420 of the resistin gene (RETN) and/or −11377 of the adiponectin gene (ADIPOQ) modulate the susceptibility to PCOS. We evaluated the genotypes of 117 women with PCOS and 380 healthy fertile controls and measured the index of insulin resistance and hormonal profiles in the PCOS women. The RETN−420G/G homozygous variant genotype occurred significantly more frequently among the PCOS group than among the control group (15.4% vs. 8.4%, p = 0.035). PCOS women with the RETN−420G/G genotype also showed significantly higher BMIs and greater insulin resistance than those with RETN−420 C/C or C/G genotypes. The ADIPOQ SNP at −11377 showed no association with PCOS. We conclude that the RETN G/G at −420 genotype is associated with PCOS in Japanese women.
    Gynecological Endocrinology 09/2009; 25(8):498-503. · 1.30 Impact Factor
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    ABSTRACT: To report a rare case of spontaneous ovarian hyperstimulation syndrome (OHSS) associated with spontaneous pregnancy and a FSH-secreting pituitary adenoma. Case report. University hospital. A 32-year-old woman with spontaneous OHSS. Transsphenoidal resection of the tumor. Regression of the symptoms of OHSS and hyperestrogenemia. At presentation, the patient's ovaries were markedly enlarged and massive ascites was seen. Her serum E(2) level was markedly elevated, but her LH level was low, and FSH was within the normal range. In addition, her TSH level was normal, and hCG was appropriate for the date of pregnancy. Subsequently, the patient developed massive thrombophlebitis in her right internal jugular and subclavian veins. Termination of the pregnancy ameliorated the accumulation of ascites, but ovarian enlargement and hyperestrogenemia persisted. No mutations of the FSH receptor, LH receptor, or aromatase genes were detected, but magnetic resonance imaging (MRI) of the head revealed a pituitary adenoma. After transsphenoidal resection of the tumor, the patient got better. A gonadotropin-secreting adenoma caused ovarian hyperstimulation (ovarian enlargement and hyperestrogenemia). In addition, spontaneous pregnancy and intrinsic hCG increased vascular permeability, which complicated the patient's disease.
    Fertility and sterility 05/2009; 92(1):390.e1-3. · 3.97 Impact Factor
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    ABSTRACT: The aim of this study is to understand the relationship between polycystic ovary syndrome (PCOS), altered hormonal characteristics and insulin resistance in female-to-male (FTM) transsexual patients. We studied 69 Japanese FTM cases, aged 17-47 years, who were seen in the Gender Identity Disorder Clinic of Sapporo Medical University Hospital between December 2003 and May 2006. The subjects had never received hormonal treatment or sex re-assignment surgery. Prior to treatment, they received physical examinations entailing measurement of anthropometric, metabolic and endocrine parameters, after which we compared the values obtained according to the presence or absence of PCOS and/or obesity. Insulin resistance was determined using the homeostasis model assessment of insulin resistance (HOMA-IR). Of the 69 participating FTM cases, 40 (58.0%) were found to have PCOS. Of the 49 for whom HOMA-IR was calculated, 15 (30.6%) also showed insulin resistance, whereas of the 59 for whom adiponectin was measured, 18 (30.5%) showed hypoadiponectinaemia. Of 69 for whom androgens were measured, 29 (39.1%) showed hyperandrogenaemia. Insulin resistance was associated with obesity but not with PCOS. In contrast, hyperandrogenaemia was associated with both PCOS and obesity. FTM transsexual patients have a high prevalence of PCOS and hyperandrogenaemia.
    Human Reproduction 05/2007; 22(4):1011-6. · 4.67 Impact Factor
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    ABSTRACT: Matrix metalloproteinases (MMP) are capable of degrading a variety of extracellular matrix (ECM) proteins and are also involved in the processing of a number of bioactive molecules. Our findings indicate that the functions of MMP in the ovary and uterus are organ-specific and time-dependently vary during the reproductive cycle. Prolactin induces structural luteolysis indicated by loss of luteal weight, protein and DNA within 36 h after pretreatment with ergot alkaloid. MMP activation appears crucial for the selective depletion of protein during luteal involution, which entails loss of ECM accompanied by apoptosis. During GnRHagonist-induced luteolysis, this response was also associated with marked increases in MMP-2, which degraded collagen type IV, and MT1-MMP, which in addition to activating MMP-2 also degrades collagen type I, III and V. We also found that the level of MT1-MMP and MMP-2 expression in the human CL is greater during the late luteal phase than during either the early mid luteal phases or during gestation, respectively. That dehydroepiandrosterone (DHEA) treatment caused the formation of cysts from antral follicles in the ovaries of immature rats while depressing MMP-2 collagenolytic activity and enhancing lysyl oxidase expression highlights the importance of collagen degradation in the process of ovulation and suggests that changes in the activities of these enzymes play a key role in ovarian cystogenesis in polycystic ovary syndrome patients. Furthermore, immunohistochemical analyses showed that MT1-MMP and FasL co-localize with TdT-mediated dUTP-biotin nick end-labeling (TUNEL)-positive apoptotic granulosa cells in rats treated with DHEA, that the Fas/FasL/Caspase-8 (death receptor-dependent) pathway is pivotal for follicular atresia and that increased levels of MT1-MMP likely play an important role in tissue remodeling during follicular atresia. After parturition, the uterus undergoes involution, a conspicuous feature characterized by a rapid reduction in the collagen content mediated by degradation of extracellular collagen bundles. Our findings strongly suggest that MT1-MMP, MMP-2 and MMP-9 are each time-dependently regulated and play important roles in tissue remodeling during postpartum uterine involution. (Reprod Med Biol 2006; 5: 235–243)
    Reproductive Medicine and Biology 11/2006; 5(4):235 - 243.
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    ABSTRACT: An approach consisting of elective cryopreservation of all embryos has been proposed for patients at risk of ovarian hyperstimulation syndrome (OHSS). Although elective cryopreservation can prevent pregnancy-induced late OHSS, it cannot prevent early OHSS. Early OHSS is reported to have been complicated with thromboembolism. The study was carried out to assess the efficacy with which the continued administration of GnRH agonist for 1 week after 5000 IU of hCG injection could prevent early OHSS. This study employed an open controlled clinical trial at three centres for treatment of infertility in Sapporo. A total of 138 patients at risk of OHSS during IVF-embryo transfer from January 1, 1998 to December 31, 1999, were assigned in turn either to a group with elective cryopreservation of all pronucleate embryos (n = 68) or to one with continuation of GnRH agonist administration for 1 week after hCG injection following elective cryopreservation (n = 70). Subsequently, they were transferred in hormone replacement cycles. The development of severe OHSS (ascites, haemoconcentration) was compared between the two groups. A total of 10% of patients developed severe OHSS necessitating hospitalization because of a marked increase in ascites in the upper abdomen and the haemoconcentration in the elective cryopreservation alone group. On the other hand, none developed severe OHSS in the GnRH agonist continuation group. In our study, continuation of GnRH agonist for 1 week after hCG injection prevented severe early OHSS following elective cryopreservation of all embryos. This treatment is safe and cost-beneficial, and should be performed promptly for patients at risk of OHSS.
    Human Reproduction 11/2002; 17(10):2548-51. · 4.67 Impact Factor