Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Yasushi Miyagawa is active.

Publication


Featured researches published by Yasushi Miyagawa.


Journal of Clinical Investigation | 2005

Transplantation of spermatogonial stem cells isolated from leukemic mice restores fertility without inducing leukemia

Kazutoshi Fujita; Hiroshi Ohta; Akira Tsujimura; Tetsuya Takao; Yasushi Miyagawa; Shingo Takada; Kiyomi Matsumiya; Teruhiko Wakayama; Akihiko Okuyama

More than 70% of patients survive childhood leukemia, but chemotherapy and radiation therapy cause irreversible impairment of spermatogenesis. Although autotransplantation of germ cells holds promise for restoring fertility, contamination by leukemic cells may induce relapse. In this study, we isolated germ cells from leukemic mice by FACS sorting. The cell population in the high forward-scatter and low side-scatter regions of dissociated testicular cells from leukemic mice were analyzed by staining for MHC class I heavy chain (H-2K b / H-2D b ) and for CD45. Cells that did not stain positively for H-2K b /H-2D b and CD45 were sorted as the germ cell-enriched fraction. The sorted germ cell-enriched fractions were transplanted into the testes of recipient mice exposed to alkylating agents. Transplanted germ cells colonized, and recipient mice survived. Normal progeny were produced by intracytoplasmic injection of sperm obtained from recipient testes. When unsorted germ cells from leukemic mice were transplanted into recipient testes, all recipient mice developed leukemia. The successful birth of offspring from recipient mice without transmission of leukemia to the recipients indicates the potential ofautotransplantation of germ cells sorted by FACS to treat infertility secondary to anticancer treatment for childhood leukemia.


Cancer Research | 2006

Isolation of Germ Cells from Leukemia and Lymphoma Cells in a Human In vitro Model: Potential Clinical Application for Restoring Human Fertility after Anticancer Therapy

Kazutoshi Fujita; Akira Tsujimura; Yasushi Miyagawa; Hiroshi Kiuchi; Yasuhiro Matsuoka; Tetsuya Takao; Shingo Takada; Norio Nonomura; Akihiko Okuyama

More than 70% of patients survive childhood cancer, but chemotherapy and radiation therapy may cause irreversible impairment of spermatogenesis. To treat infertility secondary to anticancer treatment for childhood cancer, we have developed a procedure to isolate germ cells from leukemic mice by fluorescence-activated cell sorting with two surface markers, and transplantation of isolated germ cells successfully restored fertility without inducing leukemia. In the present study, we analyzed human germ cells and human malignant cells, including five leukemia cell lines and three lymphoma cell lines, by fluorescence-activated cell sorting with antibodies against MHC class I and CD45. Testicular specimens were obtained from a patient who underwent surgery for testicular rupture. In the high forward scatter and low side scatter region, no malignant cells were found in the MHC class I-negative and CD45-negative fraction (the germ cell fraction), with the exception of K562 cells. A total of 39.2% of the germ cells were found in the germ cell fraction. A total of 1.45% of K562 cells were found in the germ cell fraction. Treatment with IFNγ induced the expression of MHC class I on K562 cells but not on germ cells and made it possible to isolate germ cells from K562 cells. In conclusion, we isolated human germ cells from malignant cells with two surface markers after treatment with IFNγ. Immunophenotyping for each patient will be necessary before isolation and induction of surface marker will be clinically applicable. (Cancer Res 2006; 66(23): 11166-71)


Biology of Reproduction | 2001

Testosterone Suppresses Spermatogenesis in Juvenile Spermatogonial Depletion (jsd ) Mice

Akira Tohda; Kiyomi Matsumiya; Yuko Tadokoro; Kentaro Yomogida; Yasushi Miyagawa; Kayoko Dohmae; Akihiko Okuyama; Yoshitake Nishimune

Abstract Male juvenile spermatogonial depletion (jsd/jsd) mice are sterile because of a failure of spermatogonial differentiation. We have previously reported the recovery of spermatogonial differentiation by suppressing the levels of gonadotropins and testosterone with Nal-Glu, a GnRH antagonist. To determine whether suppression of testosterone or the gonadotropins was responsible for spermatogenic recovery, we examined the effect of supplementation of LH or FSH along with Nal-Glu treatment. Systemic administration of flutamide, an androgen receptor antagonist, was also examined. LH supplementation elevated both serum and intratesticular testosterone levels and suppressed the recovery of spermatogonial differentiation in a dose-dependent manner. Supplementation with FSH did not affect either testosterone levels or spermatogonial differentiation. Furthermore, the mice treated with flutamide showed some recovery of spermatogonial differentiation. The overall findings revealed that testosterone action mediated by androgen receptors suppressed the spermatogonial differentiation in jsd/jsd mice and suggested that spermatogonial differentiation in the jsd mutant is highly sensitive to testosterone suppression.


BJUI | 2009

Increased vascular endothelial growth factor expression in patients with bladder pain syndrome/interstitial cystitis: its association with pain severity and glomerulations

Hiroshi Kiuchi; Akira Tsujimura; Tetsuya Takao; Keisuke Yamamoto; Jiro Nakayama; Yasushi Miyagawa; Norio Nonomura; Masami Takeyama; Akihiko Okuyama

To determine the angiogenic profiles in the bladder of patients with bladder pain syndrome (BPS)/interstitial cystitis (IC), and to evaluate the relationship between these profiles and associated clinical features including pelvic pain and glomerulations.


International Journal of Impotence Research | 2005

Comparative study on evaluation methods for serum testosterone level for PADAM diagnosis

Akira Tsujimura; Kiyomi Matsumiya; Yasushi Miyagawa; Tetsuya Takao; Kazutoshi Fujita; Shingo Takada; Minoru Koga; A Iwasa; Masami Takeyama; Akihiko Okuyama

The International Society for the Study of the Aging Male (ISSAM) recommends that a diagnosis be based on a patients total testosterone (TT), calculated free testosterone (cFT), or calculated bioavailable testosterone (cBT) for partial androgen deficiency of the aging male (PADAM). The purpose of this study was to confirm whether hypogonadism of patients with PADAM is related to symptoms and clarify which criteria of testosterone recommended by ISSAM is suitable for Japanese patients. A total of 90 patients with PADAM symptoms were included in this study. Endocrinologic profiles were reviewed as appropriate, and PADAM symptoms were judged by means of several questionnaires. Laboratory values and symptoms were compared between patients with and without hypogonadism. Even when any criterion of testosterone was used for diagnosis of hypogonadism, AMS (total and subscales), IIEF-5, or SDS scores of PADAM symptoms did not differ significantly between patients classified as having and not having hypogonadism. No other endocrinologic variables than testosterone differed significantly between them, either. PADAM symptoms are not related to testosterone level and it is still obscure whether ISSAMs criterion can be adopted for Japanese patients with PADAM. Other pathology needs to be addressed for evaluation and diagnosis of PADAM in Japan.


NeuroImage | 2007

Differential brain processing of audiovisual sexual stimuli in men: comparative positron emission tomography study of the initiation and maintenance of penile erection during sexual arousal.

Yasushi Miyagawa; Akira Tsujimura; Kazutoshi Fujita; Yasuhiro Matsuoka; Tohru Takahashi; Tetsuya Takao; Shingo Takada; Kiyomi Matsumiya; Yasuhiro Osaki; Masashi Takasawa; Naohiko Oku; Jun Hatazawa; Shigeo Kaneko; Akihiko Okuyama

The human male psychosexual cycle consists of four phases: excitation, plateau, orgasm, and resolution. Identification of the specific neural substrates of each phase may provide information regarding the brains pathophysiology of sexual dysfunction. We previously analyzed regional cerebral blood flow (rCBF) with H(2)15O-positron emission tomography (PET) during the excitation phase (initiation of penile erection) induced by audiovisual sexual stimuli (AVSS) and identified activation of the cerebellar vermis, the bilateral extrastriate cortex, and right orbitofrontal cortex, suggesting a role of cognition/emotion in the excitement phase. In the present study, we analyzed rCBF of the same six healthy volunteers during the plateau phase (maintenance of penile erection) induced by AVSS and compared the results with those of the excitation phase. Penile rigidity was monitored in real time with RigiScan Plus during PET scanning. Images were analyzed by statistical parametric mapping (SPM) software, and rCBF in the amygdala, hypothalamus, anterior cingulate, and insula was measured. During the plateau phase, primary subcortical activation was noted in the right ventral putamen, indicating motivational factors in the sexual response via the limbic reward circuit. A significant increase in rCBF in the left hypothalamus was also observed during the plateau phase. The right anterior cingulate and left insula were specifically activated during the excitation phase but not during the plateau phase. These results indicate a significant role of the ventral putamen and the hypothalamus in the plateau phase and confirm that paralimbic and limbic components of the human brain differentially coordinate the sexual response in a psychosexual phase-dependent manner.


The Journal of Urology | 2006

Salvage Microdissection Testicular Sperm Extraction After Failed Conventional Testicular Sperm Extraction in Patients With Nonobstructive Azoospermia

Akira Tsujimura; Yasushi Miyagawa; Tetsuya Takao; Shingo Takada; Minoru Koga; Masami Takeyama; Kiyomi Matsumiya; Fujioka H; Akihiko Okuyama

PURPOSE TESE is considered the best procedure for identifying a tubule for spermatozoa retrieval. This technique improves the SRR to around 50%. However, it has been unclear whether it is useful in patients in whom conventional TESE has failed. We compared the outcome of microdissection TESE in patients in whom conventional TESE failed to that in patients who did not undergo conventional TESE. We also evaluated relations between the outcome of salvage microdissection TESE and the characteristics of previous conventional TESE. MATERIALS AND METHODS A total of 46 patients with nonobstructive azoospermia in whom salvage microdissection TESE was performed after failed conventional TESE were included. Patient characteristics and the SRR were compared between these patients and 134 in whom conventional TESE had not been performed previously. The previous TESE procedure, testicular histology and interval between TESEs were also evaluated. RESULTS Patient characteristics did not differ significantly between the groups. The microdissection TESE SRR also did not differ significantly between the groups (45.7% vs 44.0%). The possibility of successful spermatozoa retrieval by salvage microdissection TESE remained regardless of the previous failure of any other TESE procedure and regardless of testicular histology. The salvage microdissection TESE SRR was not related to the interval between TESEs. CONCLUSIONS Because salvage microdissection TESE is effective in patients in whom conventional TESE has failed, this option should be made available to them with the understanding that extended followup after salvage microdissection TESE is necessary due to the risk of hypogonadism.


Journal of Andrology | 2009

Single-nucleotide polymorphisms of the PRDM9 (MEISETZ) gene in patients with nonobstructive azoospermia.

Shinji Irie; Akira Tsujimura; Yasushi Miyagawa; Tomohiro Ueda; Yasuhiro Matsuoka; Yasuhisa Matsui; Akihiko Okuyama; Yoshitake Nishimune; Hiromitsu Tanaka

To investigate the possible association between variations in the PRDM9 (MEISETZ) gene and impaired spermatogenesis in humans, we screened for mutations in the human PRDM9 gene using DNA from 217 sterile male patients and 162 proven fertile male volunteers. Two single-nucleotide polymorphisms (SNPs), 17353G>T (Gly433Val) and 18109C>G (Thr685Arg), were identified, as well as an intronic SNP, 15549G>T. These SNPs were identified in the heterozygous state in separate patients who demonstrated azoospermia. Neither variant was identified in fertile subjects. Our results suggest that mutations in PRDM9 may cause idiopathic infertility in human males.


The Journal of Sexual Medicine | 2011

Vardenafil and Resveratrol Synergistically Enhance the Nitric Oxide/Cyclic Guanosine Monophosphate Pathway in Corpus Cavernosal Smooth Muscle Cells and Its Therapeutic Potential for Erectile Dysfunction in the Streptozotocin‐Induced Diabetic Rat: Preliminary Findings

Shinichiro Fukuhara; Akira Tsujimura; Hidenobu Okuda; Keisuke Yamamoto; Tetsuya Takao; Yasushi Miyagawa; Norio Nonomura; Akihiko Okuyama

INTRODUCTION Phosphodiesterase type 5 (PDE5) inhibitors are very effective agents for erectile dysfunction; however, specific patient populations are hard to treat. The efficacy of PDE5 inhibitors is limited because a minimum amount of nitric oxide (NO) is necessary. Resveratrol, a plant polyphenol, is reported to activate endothelial NO synthase (eNOS) through activation of sirtuin 1. We previously reported that human corpus cavernosal smooth muscle cells (CCSMCs) express eNOS and synthesize cyclic guanosine monophosphate (cGMP) via the NO/cGMP pathway. AIM To investigate the ability of resveratrol and/or vardenafil to increase cGMP in an in vitro model using CCSMCs and to improve erectile function in an in vivo rat model of streptozotocin (STZ)-induced diabetes. METHODS CCSMCs were treated with resveratrol and/or vardenafil. Twenty male Sprague-Dawley rats were randomly divided into five groups (N = 4 in each group): age-matched controls, diabetic controls, and diabetic rats treated with resveratrol, vardenafil, or both in combination for the last 4 weeks of an 8-week period of diabetes induction. MAIN OUTCOME MEASURES Intracellular cGMP measurement, intracovernous pressure (ICP)/mean arterial pressure (MAP) ratio, and smooth muscle/collagen ratio. RESULTS Intracellular cGMP level was elevated by resveratrol treatment in CCSMCs. The combination treatment of resveratrol and vardenafil had a synergistic effect. Diabetic rats showed impairment of erectile function. Treatment with either resveratrol or vardenafil improved ICP/MAP ratio, and combination therapy with resveratrol and vardenafil had a synergistic effect in improvement of ICP/MAP. CONCLUSIONS Treatment with either resveratrol or vardenafil elevated cGMP level in CCSMCs and improved erectile function in STZ-induced diabetic rats. Furthermore, a synergistic effect was observed in vitro and in vivo. Resveratrol or combination therapy of resveratrol and vardenafil can improve erectile function in which NO release is impaired, although further study is needed to confirm the results.


The Journal of Urology | 2009

Sesquiterpene Lactone Parthenolide Ameliorates Bladder Inflammation and Bladder Overactivity in Cyclophosphamide Induced Rat Cystitis Model by Inhibiting Nuclear Factor-κB Phosphorylation

Hiroshi Kiuchi; Tetsuya Takao; Keisuke Yamamoto; Jiro Nakayama; Yasushi Miyagawa; Akira Tsujimura; Norio Nonomura; Akihiko Okuyama

PURPOSE Cyclophosphamide (Sigma) is associated with urological complications, including irritative voiding symptoms and hemorrhagic cystitis. Evidence suggests that tumor necrosis factor-alpha (R&D Systems), interleukin-1beta and cyclooxygenase-2 are directly involved in the pathogenesis of cyclophosphamide induced cystitis and these molecules depend on transcription factor NF-kappaB for maximal secretion. Additionally, sesquiterpene lactone parthenolide has been shown to be a potent nuclear factor-kappaB inhibitor. We hypothesized that enhanced nuclear factor-kappaB activity contributes to cyclophosphamide induced cystitis and, therefore, it may be an attractive target for preventing cyclophosphamide cystitis. We determined whether parthenolide could be used as a preventive agent for hemorrhagic cystitis and bladder overactivity. Moreover, we determined the molecular mechanisms of parthenolide on the inhibitory action of nuclear factor-kappaB in inflammatory human benign urothelial cells. MATERIALS AND METHODS Rats were pretreated with parthenolide or vehicle solution and administered cyclophosphamide. Histological analysis and cystometry were performed 24 hours after cyclophosphamide administration. Human urothelial cells were pretreated with parthenolide and stimulated with tumor necrosis factor-alpha. Western blotting and immunofluorescence were performed to determine activation of the cyclooxygenase-2 and nuclear factor-kappaB pathway. RESULTS Parthenolide pretreatment inhibited bladder inflammation as well as bladder overactivity and it was also associated with nuclear factor-kappaB activation in the bladder. Parthenolide dose dependently suppressed tumor necrosis factor-alpha induced cyclooxygenase-2 expression and prevented nuclear factor-kappaB phosphorylation as well as nuclear factor-kappaB nuclear translocation and IkappaBalpha phosphorylation/degradation. CONCLUSIONS Nuclear factor-kappaB may have a crucial role in the pathogenesis of cyclophosphamide induced cystitis models. Parthenolide ameliorates bladder inflammation and bladder overactivity, and it might be a promising agent for preventing cyclophosphamide induced complications.

Collaboration


Dive into the Yasushi Miyagawa's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Hiromitsu Tanaka

Nagasaki International University

View shared research outputs
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge