Munekazu Naito

Tokyo Medical University, Edo, Tōkyō, Japan

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Publications (69)140.03 Total impact

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    ABSTRACT: Testicular cell transplantation has generally been performed by using immune-deficient recipient mice to investigate the biology of spermatogonial stem cells (SSCs), the production of transgenic animals, and restoration of fertility. Recently, we demonstrated that rat spermatogenesis can occur in the seminiferous tubules of immune-competent recipient mice via pretreatment with busulfan (Myleran, 1, 4-butanediol methanesulfonate, 40 mg/kg) after transplantation of rat SSCs. However, considering the immunosuppressive effect of busulfan, there is a possibility that busulfan itself causes immune suppression in immune-competent recipient mice. The aim of this study was to determine the effects of busulfan on the immune system and spermatogenesis in immune-competent recipient mice. The results showed that at 60 days after busulfan treatment, just the same time as the transplantation, the recovery could be seen in the immune system including cell counts and functions of T and B lymphocytes in the spleen, but the spermatogenesis was more compromised. This study demonstrated that after busulfan pretreatment the immune system in immune-competent recipient mice had recovered by the time that rat spermatogenesis could occur in the murine testis. It became clear that xenogenic spermatogenesis can be tolerated in seminiferous tubules in the testes of immune-competent mice.
    Anatomical Science International 11/2014; · 0.63 Impact Factor
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    ABSTRACT: Experimental autoimmune orchitis is a useful model for studying testicular inflammation and germ/immune cell interactions. Th17 cells and their hallmark cytokine IL17A were reported to be involved in the development of autoimmune orchitis. The aim of the present work is to investigate the pathogenic role of IL17A in rat testis. In vitro experiments were performed in order to analyze effects of IL17A on Sertoli cell tight junctions. The addition of IL17A to normal rat Sertoli cell cultures induced a significant decline in transepithelial electrical resistance and a reduction of occludin expression and redistribution of occludin and claudin 11, altering the Sertoli cell tight junction barrier. Intratesticular injection of 1 μg of recombinant rat IL17A to Sprague-Dawley rats induced increased blood-testis barrier permeability, as shown by the presence of biotin tracer in the seminiferous tubule adluminal compartment, and delocalization of occludin and claudin 11. Results showed that IL17A induced focal inflammatory cell infiltration in the interstitium and germ cell sloughing in adjacent seminiferous tubules. Moreover, an increase in TUNEL+ apoptotic germ cells was also observed. Inflammatory ED1+ macrophages were the main population infiltrating the interstitium following IL17A injection. This correlated with an increase in mRNA expression of the monocyte chemoattractant protein Ccl2, its receptor Ccr2 and the vascular cell adhesion molecule Vcam1. Overall results suggest a relevant role of IL17A in the development of testicular inflammation, facilitating the recruitment of immune cells to the testicular interstitium and inducing impairment of blood-testis barrier function.
    Cell and Tissue Research 09/2014; · 3.68 Impact Factor
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    ABSTRACT: Scimitar syndrome is a rare anomaly involving a pulmonary vein flowing into the inferior vena cava (scimitar vein) and is commonly associated with lung hypoplasia wherein a scimitar vein drains the entire lung. We report a rare case of a scimitar vein draining only the right inferior lobe found in a 77-year-old male cadaver. In this case, no hypoplastic lung or abnormal lobulation were observed. The scimitar vein drained the inferior lobe of the right lung after piercing the diaphragm and draining into the inferior vena cava. The remaining two right pulmonary veins, draining the superior and middle lobes, terminated into the left atrium. To the best of our knowledge, this is the first report of a scimitar vein during gross anatomical dissection in an adult cadaver. In adults, scimitar veins are often benign, incidental findings, and little is known about them. The present case of a scimitar vein partially draining the lung without lung hypoplasia offers important insights into the formative processes of the pulmonary venous system.
    Anatomical science international. 03/2014;
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    ABSTRACT: Diethylstilbestrol (DES), an endocrine-disrupting chemical, is an infamous artificial estrogenic compound. Although neonatal exposure to DES has been shown to result in inflammation of the male reproductive system, it has not, to our knowledge, been reported to induce testicular inflammation. Here we report that neonatal exposure to DES caused granulomatous orchitis with spermatogenic disturbance in 4 of 17 ICR male mice at 12 weeks of age. In the animals with spermatogenic disturbance, we observed either seminiferous tubules containing only cells with Sertoli cell features (likely Sertoli cell syndrome), or tubule cells in maturation arrest that contained only spermatogonia and/or spermatocytes. Following neonatal DES exposure, 5-week-old mice exhibited inflammation in cauda epididymis; by 8 weeks, the inflammation had spread to all segments of epididymis but not the testis; by 12 weeks, inflammation of the epididymis was observed in all mice. These data indicated that cauda epididymis has increased sensitivity to neonatal DES exposure compared to other segments of epididymis and testis. The data also implied that neonatal DES exposure-induced inflammation in cauda epididymis extended gradually to the testis via corpus and caput during development.
    Anatomical science international. 01/2014;
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    ABSTRACT: The testis is an organ with immune privilege. The comprehensive blood-testis barrier formed by Sertoli cells protects autoimmunogenic spermatozoa and spermatids from attack by the body's immune system. The interleukin (IL)-6/IL-12 family cytokines IL-12 (p35/p40), IL-23 (p19/p40), IL-27 (p28/Epstein-Barr virus-induced gene 3 [EBI3]), and IL-35 (p35/EBI3) play critical roles in the regulation of various immune responses, but their roles in testicular immune privilege are not well understood. In the present study, we investigated whether these cytokines are expressed in the testes and whether they function in the testicular immune privilege by using mice deficient in their subunits. Expression of EBI3 was markedly increased at both mRNA and protein levels in the testes of 10- or 12-week-old wild-type mice as compared with levels in 2-week-old mice, whereas the mRNA expression of p40 was markedly decreased and that of p35 was conserved between these two groups. Lack of EBI3, p35, and IL-12 receptor β2 caused enhanced infiltration of lymphocytes into the testicular interstitium, with increased interferon-γ expression in the testes and autoantibody production against mainly acrosomal regions of spermatids. Spermatogenic disturbance was more frequently observed in the seminiferous tubules, especially when surrounded by infiltrating lymphocytes, of these deficient mice than in those of wild-type mice. In particular, p35-deficient mice showed the most severe spermatogenic disturbance. Immunohistochemical analyses revealed that endothelial cells and peritubular cells in the interstitium were highly positive for p35 at both ages, and CD163+ resident macrophages positive for p35 and EBI3, possibly producing IL-35, were also detected in the interstitium of 12-week-old mice but not those of 2-week-old mice. These results suggest that p35 helps in maintaining the testicular immune privilege, in part in an IL-35-dependent manner.
    PLoS ONE 01/2014; 9(4):e96120. · 3.53 Impact Factor
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    ABSTRACT: Colostomy is conventional treatment for anal dysfunction. Recently, a few trials of anorectal transplantation in animals have been published as a potential alternative to colostomies; however, further development of this technique is required. In this study, we utilized a canine model of anorectal transplantation, evaluated the patency of our microsurgical anastomoses, and assessed the perfusion of the transplanted anus. We designed a canine anorectal transplantation model, wherein anorectal autotransplantation was performed in four healthy beagle dogs by anastomoses of the lower rectum, the bilateral pudendal arteries (PAs) and veins (PVs), and pudendal nerves (PNs). Postoperative graft perfusion was measured by indocyanine green (ICG) angiography and histological examination. The length of the anorectal graft including perianal skin, anal sphincter muscle, bilateral PAs, PVs, and PNs was 4.9 ± 0.3 cm. All diameters of the PAs, PVs, and PNs were large enough to be microscopically anastomosed. Both ICG angiography and histological examination demonstrated good graft perfusion, except for one case that lead to venous congestion. These results show that anastomosis of the bilateral PAs, PVs, and PNs is required for anorectal transplantation. This is the first successful report of canine anorectal autotransplantation.
    Scientific reports. 01/2014; 4:6312.
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    ABSTRACT: Exposure to di-(2-ethylhexyl) phthalate (DEHP) has been reported to induce spermatogenic disturbance through oxidant stress and affect the immune system as an adjuvant. However, the effect of DEHP on the testicular immune microenvironment has not yet been investigated. In the present study, we examined the testicular immune microenvironment after exposure to doses of DEHP, previously identified as no-observed-adverse-effect levels. Adult male mice were administered food containing 0%, 0.01% or 0.1% DEHP and then testes were analyzed. The results showed that a slight but significant spermatogenic disturbance appeared in the 0.1% DEHP group but not in the 0.01% DEHP group at 8 weeks. It was also demonstrated that lymphocytes and F4/80- and MHC class II- positive cells were significantly increased with the elevation of IL-10 and IFN-γ mRNA expressions in the testes of not only the 0.1% DEHP group but also the 0.01% DEHP group at 8 weeks. Histochemical analyses involving horseradish peroxidase (HRP) as a tracer showed that a little blood-borne HRP had infiltrated into the lumen of a few seminiferous tubules beyond the blood-testis-barrier in both the 0.1% and 0.01% DEHP groups at 8 weeks. This indicates that a dose of DEHP that has little effects on spermatogenesis can change the testicular immune microenvironment with functional damage of the blood-testis barrier.
    Journal of Reproduction and Development 07/2013; · 1.76 Impact Factor
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    ABSTRACT: The aim of this study was to identify the characteristics of serum autoantibodies in experimental autoimmune orchitis (EAO) induced by immunization with syngeneic testicular germ cells (TGC) alone in mice. The serum autoantibodies were analyzed by enzyme-linked immunosorbent assay (ELISA), Western blotting, and immunohistochemical staining. Serum autoantibody titers against TGC and epididymal spermatozoa (ES) gradually increased with the development of EAO. At the initial stage of EAO, serum autoantibodies reacted with only a few antigens of TGC and ES, while in the later stage, the reactions with various antigens of TGC and ES occurred. However, the autoantibodies were specific to the testis and epididymis but not to other organs. These results indicate that titers and kinds of autoantibodies in TGC-immunized mice increase with EAO development and they are specific to TGC and ES.
    American Journal Of Reproductive Immunology 07/2013; · 3.32 Impact Factor
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    ABSTRACT: There are many reports on variations in the inferior vena cava (IVC), particularly double IVC (DIVC) and left IVC (LIVC). However, no systematic report has recorded iliac vein (IV) flow patterns in the DIVC and LIVC. In this study, we examined IV flow patterns in both DIVC and LIVC observed during gross anatomy courses conducted for medical students and in previously reported cases. During the gross anatomy courses, three cases of DIVC and one case of LIVC were found in 618 cadavers. The IV flow pattern from these four cases and all other previously reported cases can be classified into one of the following three types according to the vein into which the internal iliac vein drained: the ipsilateral external IV; confluence of the ipsilateral external IV and IVC; and the communicating vein, which connects the IVC and the contralateral IVC or its iliac branch. This classification, which is based on the internal IV course, is considered to be useful because IV variations have the potential to cause clinical problems during related retroperitoneal surgery, venous interventional radiology, and diagnostic procedures for pelvic cancer.
    Anatomical science international. 05/2013;
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    ABSTRACT: Experimental autoimmune orchitis (EAO), comprising a breakdown of the testicular immune privilege, is one of the models of immunological male infertility. EAO is characterised by CD4 + T-cell-dependent lymphocytic inflammation and augmented delayed-type hypersensitivity (DTH) against testicular antigens. We previously established an EAO model in mice by immunisation with viable syngeneic testicular germ cells (TGC) alone. However, the sequential change of DTH during development of this EAO has not been analysed yet. In this study, the DTH response during TGC-induced EAO was investigated by the injection of syngeneic TGC protein into the ears of mice. The results showed that a significant DTH response was observed on injection of 20 μg TGC protein, but not on that of 0.2 or 2 μg TGC protein. Also, the level of the DTH response to 20 μg TGC protein was highly relevant to the pathology of EAO development. These results indicate that the DTH response on injection of 20 μg TGC protein into the ears of mice is effective for predicting the pathology of EAO development.
    Andrologia 05/2013; · 1.55 Impact Factor
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    ABSTRACT: Neonatal estrogen treatment (NET) induces morphological changes in male reproductive organs. NET with β-estradiol 17-cypionate is reported to induce inflammation with stromal-epithelial abnormalities in the prostate and seminal vesicles in post-pubertal mice. The aim of this study was to investigate the histopathology of the testis, ductuli efferentes, epididymis, and vas deferens in mice after NET with β-estradiol 17-cypionate. No morphological changes in these organs were observed until 4 weeks after NET. However, some inflammatory cells were found in epididymis and vas deferens 6 weeks after NET. Eight weeks after NET, inflammatory cells spread to the ductuli efferentes and inflammation was severe from 6 to 12 weeks after NET. Inflammatory cells were never seen in the whole testis, but cystic dilatation of the rete testes with spermatogenic disturbance was found around the mediastinum testis. Many inflammatory cells emigrated into the lumen of the epididymis, resulting in complete absence of spermatozoa in the vas deferens. Most of the inflammatory cells penetrating into the epithelial layers of epididymal ducts were neutrophils. These results indicate that in post-pubertal mice, NET with β-estradiol 17-cypionate induces inflammation in the ductuli efferentes, epididymis, and vas deferens, but not in the testis, provoking obstructive azoospermia.
    Medical Molecular Morphology 03/2013; · 1.17 Impact Factor
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    ABSTRACT: Although bilateral megaureters are not an infrequent occurrence in the urinary tract, bilateral megaureters associated with bilateral renal pelvis dilatation and a giant urinary bladder appear to be rare. In this paper, a cadaver case of an adult Japanese male with bilateral megaureters is described. In addition to describing and illustrating this case, the anatomy and etiology of these anomalous structures is discussed with a brief review of the literature.
    Anatomical science international. 02/2013;
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    ABSTRACT: Lymphangiogenesis occurs in various organs under inflammatory conditions. Recently, it was demonstrated that activated macrophages play an important role in the process of lymphangiogenesis. However, lymphangiogenesis during testicular inflammation has not yet been studied. Here, we investigated lymphangiogenesis in experimental autoimmune orchitis, a immunologic male infertility model, in mice. Histological changes were observed using immunohistochemical staining with the monoclonal antibodies against F4/80 (mature macrophage marker), lymph vessel endothelium HA-receptor 1 (LYVE-1) (lymphatic endothelial cells marker) and CD31 (endothelial cells marker). The expression of angiogenesis and lymphangiogenesis factors, such as vascular endothelial growth factor (VEGF)-A, VEGF-C, VEGF-D and TNF-α, which are secreted by activated macrophages, were examined using real-time RT-PCR. The results showed that lymphangiogenesis occurred along the undersurface of the tunica albuginea but not into the interstitium proper between the seminiferous tubules (STs) during the orchitis. It was noted that some F4/80-positive macrophages expressed LYVE-1 at the undersurface of the tunica albuginea and also in the testicular interstitium proper. RT-PCR analysis revealed that the expressions of VEGF-A, VEGF-D and TNF-α were significantly increased but that of VEGF-C remained unchanged in the inflammatory testes. This study suggests that testicular macrophages are involved in the specific lymphangiogenesis in the chronic inflammation.
    Andrology 01/2013; 1(1):147-54. · 3.37 Impact Factor
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    ABSTRACT: Anorectal transplantation is a method for patients who have lost their anorectal function or suffer from congenital anorectal dysfunction to recover this function, and this has been investigated in experimental animal models using pigs, dogs, and rats. In this study, we performed an examination of anorectal transplantation in human cadavers to investigate whether this procedure could be performed in patients. A 77-year-old woman cadaver 1 was used as the donor and a 98-year-old woman cadaver 2 was used as the recipient. Initially, abdominoperineal excision of the anus and rectum (the Miles' operation) was performed on the recipient. Next, an anorectal graft containing the pudendal nerve (PN), pudendal artery (PA), pudendal vein (PV), inferior mesenteric artery (IMA), and inferior mesenteric vein (IMV) was harvested from the donor. The donor graft was transplanted into the recipient by intestinal anastomosis and microneurovascular anastomoses orthotopically. The diameters of the PN (right/left), IMA, and IMV were 2.5 mm/2.5 mm, 2.0 mm, and 1.5 mm, respectively, in cadaver 1, and 2.0 mm/2.0 mm, 2.0 mm, and 2.0 mm, respectively, in cadaver 2. The length of the PN, PA, PV, IMA, and IMV in the graft was sufficient to allow proper anastomosis. This preliminary study indicated that human anorectal transplantation was possible anatomically and technically. We anticipate our study will aid in the potential future application of this procedure to human patients.
    PLoS ONE 01/2013; 8(7):e68977. · 3.53 Impact Factor
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    ABSTRACT: Experimental autoimmune orchitis (EAO) is a model of immunologic male infertility and pathologically characterized by lymphocytic inflammation, which causes breakdown of the testicular immune privilege with spermatogenic disturbance. Generally, murine EAO is induced by immunization with testicular homogenate (TH) from the testes of donor mice + complete Freund's adjuvant (CFA) + Bordetella pertussigens (BP), and it has been considered that treatment with these two adjuvants is required to enhance the immune response against testicular antigens. However, there remains a possibility that CFA and BP may affect autoimmune responses against the testicular antigens without TH. In the present study, we examined this possibility using real-time RT-PCR, Western blotting and immunohistochemical staining. The results demonstrated that immunization with TH in combination with CFA and BP evoked more severe EAO than that with only TH. Real-time RT-PCR analyses revealed that Fas mRNA expression in TH+CFA+BP-induced EAO was significantly higher than that in TH-induced EAO. Interestingly, IL-6 mRNA expression dramatically increased in TH+CFA+BP-induced EAO; however, no apparent change in IL-6 mRNA expression occurred in TH-induced EAO. It was also noted that treatment with CFA and BP alone augmented autoimmune reactions against some testicular autoantigens. These results indicates that these adjuvants are helpful in evoking severe EAO, and treatment with the adjuvants alone can evoke autoimmune reactions against some testicular autoantigens despite the use of no TH.
    Journal of Reproduction and Development 12/2012; · 1.76 Impact Factor
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    ABSTRACT: Clinically, 60-75% of male infertility cases are categorized as idiopathic spermatogenic disturbance. In previous studies of this condition, lymphocytic infiltration and immune deposits were present in several testis biopsy specimens, indicating that inflammatory or immunological factors contribute to the occurrence of the lesions. However, there is currently little evidence regarding immunological infertility in men. Previously, we established an immunological infertility model, experimental autoimmune orchitis (EAO), that can be induced in mice by two subcutaneous injections of viable syngeneic testicular germ cells without the use of any adjuvant. In this EAO model, lymphocytes surround the tubuli recti and then induce spermatogenic disturbance. In addition, after the active inflammation stage of this model, the seminiferous epithelium is damaged irreversibly, resembling the histopathology of human male idiopathic spermatogenic disturbance. In the majority of patients with testicular autoimmunity, there is a chronic and asymptomatic development of the inflammatory reaction. Therefore, this disease is very difficult to diagnose at the ongoing stage, and it is possible that the histopathology of idiopathic spermatogenic disturbance in the clinic is reported at the post-active inflammation stage of autoimmune orchitis. In this review, the histopathology of EAO before and after inflammation is discussed, comparing it with human orchitis.
    Medical Molecular Morphology 12/2012; 45(4):185-9. · 1.17 Impact Factor
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    ABSTRACT: We previously established an immunological infertility model, experimental autoimmune orchitis (EAO), which can be induced by two subcutaneous injections of viable syngeneic testicular germ cells on days 0 and 14 in mice without using any adjuvant. In this EAO model, CD4+ T-cell-dependent lymphocytic infiltration and immune deposits were found with spermatogenic disturbance on day 120. However, the late stage of EAO (= postactive inflammation stage on day 365) has not yet been investigated. Therefore, we investigated the histopathological characteristics of the late stage. The results revealed that the lymphocytic infiltration finally resolved; however, the seminiferous epithelium persistently showed maturation arrest and the Sertoli cell-only feature. In the seminiferous tubules showing maturation arrest, both proliferation and apoptosis of germ cells had occurred simultaneously. It was also noted that there were deposits of immunoglobulin G and the third component of complement on the thickened basement membrane of seminiferous tubules in the late stage of EAO. These results indicate that histopathology after active inflammation in EAO comprises persistent damage to the seminiferous epithelium and may resemble the histopathology of "idiopathic disturbance of spermatogenesis" in man.
    Medical Molecular Morphology 12/2012; 45(1):35-44. · 1.17 Impact Factor
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    ABSTRACT: A rare case of multiple renal arteries was found in a 78-year-old female cadaver undergoing routine dissection. The characteristic findings in the cadaver included the presence of four right and four left renal arteries with one common trunk (a total of nine renal arteries). This variation may represent an immature form of complicated development of the renal arteries.
    Anatomical science international. 11/2012;
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    ABSTRACT: The authors describe three anatomic variations, circumaortic, retroaortic left renal vein, and retropelvic tributary of the renal vein, in Japanese cadavers. The incidences and the clinical significances of these variations are discussed with a detailed review of the literature. The median incidences of circumaortic left renal vein (CLRV) were 7.0 % in cadavers examined and 1.8 % in clinical subjects examined. The detection of CLRV in CT/MDCT or angiography was relatively difficult compared with that by cadaver dissection. The median incidences of retroaortic left renal vein (RLRV) were 1.7 % in cadavers examined and 2.2 % in clinical subjects examined. The detection of RLRV was lower in operations, and relatively easy by ultrasonography. The incidence of retropelvic tributary of the renal vein ranged from 30.0 to 46.4 %, which is very frequent. Moreover, the incidences of communicating veins between the left renal vein and retroperitoneal veins ranged from 30.0 to 84.2 % in cadaver dissections and from 34.0 to 75.8 % in clinical reports.
    Anatomia Clinica 04/2012; 34(9):799-804. · 0.93 Impact Factor
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    ABSTRACT: Experimental autoimmune orchitis (EAO) is characterized by T cell-dependent lymphocytic inflammation and seminiferous tubule damage, which can result in the death of germ cells. The aim of the present study is to investigate the roles of the Fas/Fas-L and Bax/Bcl-2 systems in the death of germ cells in mice with EAO that is induced by immunization with syngeneic testicular germ cells (TGC). The results using real-time reverse transcription-polymerase chain reaction and immunostaining show that many terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining germ cells were present in seminiferous tubules during the active inflammation stage, and these cells were persistently observed in the seminiferous epithelium until the postactive inflammation stage. Intratesticular mRNA expression levels of both Fas and Bax were increased during the active inflammation stage and were dramatically decreased during the post-active inflammation stage. In contrast, the intratesticular mRNA expression levels of both Fas-L and Bcl-2 did not show significant changes during the active inflammation stage but showed extreme increases during the post-active inflammation stage. Immunohistochemically, some Fas- and Bax-positive germ cells were detected during the active inflammation stage, but these were hardly found during the post-active inflammation stage. In contrast, some Fas-L- and Bcl-2-positive germ cells were found during the active inflammation stage, and many of these were also observed during the post-active inflammation stage. These results indicate that germ cell death during TGC-induced EAO is mediated by the Fas/Fas-L and Bax/Bcl-2 systems during the active inflammation stage but not during the post-active inflammation stage.
    Journal of Andrology 03/2012; 33(5):824-31. · 3.37 Impact Factor

Publication Stats

294 Citations
140.03 Total Impact Points


  • 2005–2014
    • Tokyo Medical University
      • • Department of Anatomy
      • • Department of Biochemistry
      Edo, Tōkyō, Japan
  • 2012–2013
    • The University of Tokyo
      • Faculty & Graduate School of Medicine
      Tōkyō, Japan
    • Kanazawa University
      • Department of Functional Anatomy
      Kanazawa, Ishikawa, Japan
  • 2010–2012
    • Chiba University
      • Graduate School of Medicine
      Tiba, Chiba, Japan