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Dive into the research topics where Tadahiro Isoyama is active.

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Featured researches published by Tadahiro Isoyama.


Cancer Research | 2005

HYAL1 Hyaluronidase in Prostate Cancer: A Tumor Promoter and Suppressor

Vinata B. Lokeshwar; Wolfgang H. Cerwinka; Tadahiro Isoyama; Bal L. Lokeshwar

Hyaluronidases degrade hyaluronic acid, which promotes metastasis. HYAL1 type hyaluronidase is an independent prognostic indicator of prostate cancer progression and a biomarker for bladder cancer. However, it is controversial whether hyaluronidase (e.g., HYAL1) functions as a tumor promoter or as a suppressor. We stably transfected prostate cancer cells, DU145 and PC-3 ML, with HYAL1-sense (HYAL1-S), HYAL1-antisense (HYAL1-AS), or vector DNA. HYAL1-AS transfectants were not generated for PC-3 ML because it expresses little HYAL1. HYAL1-S transfectants produced < or = 42 milliunits (moderate overproducers) or > or = 80 milliunits hyaluronidase activity (high producers). HYAL1-AS transfectants produced <10% hyaluronidase activity when compared with vector transfectants (18-24 milliunits). Both blocking HYAL1 expression and high HYAL1 production resulted in a 4- to 5-fold decrease in prostate cancer cell proliferation. HYAL1-AS transfectants had a G2-M block due to decreased cyclin B1, cdc25c, and cdc2/p34 expression and cdc2/p34 kinase activity. High HYAL1 producers had a 3-fold increase in apoptotic activity and mitochondrial depolarization when compared with vector transfectants and expressed activated proapoptotic protein WOX1. Blocking HYAL1 expression inhibited tumor growth by 4- to 7-fold, whereas high HYAL1 producing transfectants either did not form tumors (DU145) or grew 3.5-fold slower (PC-3 ML). Whereas vector and moderate HYAL1 producers generated muscle and blood vessel infiltrating tumors, HYAL1-AS tumors were benign and contained smaller capillaries. Specimens of high HYAL1 producers were 99% free of tumor cells. This study shows that, depending on the concentration, HYAL1 functions as a tumor promoter and as a suppressor and provides a basis for anti-hyaluronidase and high-hyaluronidase treatments for cancer.


Urological Research | 1999

Postmeiotic modifications of spermatogenic cells are accompanied by inhibition of telomerase activity.

Yasuhisa Yamamoto; Nikolaos Sofikitis; Koji Ono; Takayuki Kaki; Tadahiro Isoyama; Nobuo Suzuki; Ikuo Miyagawa

Abstract We investigated whether testicular telomerase activity is due to telomerase expression in all cells or expression in a limited number of cells. Telomerase activity was assayed in highly purified fractions of spermatogonia cells plus primary spermatocytes, secondary spermatocytes plus round spermatids, secondary spermatocytes plus spermatids plus spermatozoa, round spermatids, or spermatozoa prepared from healthy or cryptorchid animals. Telomerase activity was additionally assayed in testicular tissue of prepubertal animals and animals with Sertoli cell only pathophysiology. Telomerase activity was detected in fractions containing primary spermatocytes and/or secondary spermatocytes and/or spermatids. Fractions enriched in round spermatids were positive for telomerase activity. In contrast, spermatozoa or Sertoli cell fractions were negative for telomerase activity. Using the relative telomerase activity assay and the sensitive quantitative telomerase assay to quantify telomerase activity, we showed that induction of cryptorchidism does not result in quantitative alterations in testicular tissue telomerase activity. In addition, elimination of round spermatids does not lead to significant alterations in testicular tissue telomerase activity. The present results suggest that the male gamete telomerase activity is inhibited during spermiogenesis. Furthermore, it appears that spermatogonia/primary spermatocytes are the main sources of telomerase activity in the testis.


Urologic Oncology-seminars and Original Investigations | 2013

The significant immunological characteristics of peripheral blood neutrophil-to-lymphocyte ratio and Fas ligand expression incidence in nephrectomized tumor in late recurrence from renal cell carcinoma

Takehiro Sejima; Hideto Iwamoto; Shuichi Morizane; Nobuyuki Hinata; Akihisa Yao; Tadahiro Isoyama; Motoaki Saito; Atsushi Takenaka

OBJECTIVE In order to characterize the significance of immune system function in patients with advanced renal cell carcinoma (RCC), we investigated the interactive relationships among the following parameters: metastatic characteristics, expression of Fas ligand (FasL) in nephrectomized specimens, immunological parameters, and patients prognosis. MATERIALS AND METHODS Thirty-five patients with advanced RCC were stratified into 3 groups according to the characteristics of metastasis timing, at first presentation (mFP), within 5 years of nephrectomy (early-recurrence), after 5 years (late-recurrence). Immunological parameters [hemoglobin, lymphocyte count, neutrophil/lymphocyte ratio (NLR), serum albumin, Eastern Cooperative Oncology Group (ECOG) performance status (PS), and Charlson Comorbidity Index], FasL expression in RCC, and patient prognosis from occurrence of metastasis were compared among the groups. Thirty-five patients were also stratified into 2 groups according to FasL positivity and individual parameters. Patients prognosis and the remaining immunological parameters were compared between groups. RESULTS The NLRs of the late-recurrence group were significantly lower than those of the mFP (P = 0.0004) and early-recurrence (P = 0.013) groups. The FasL mRNA positivity of the late-recurrence group was significantly lower than those of the mFP (P = 0.001) and early-recurrence (P = 0.0277) groups. The prognosis of the late-recurrence group was significantly better than that of the early-recurrence group (P = 0.0255). NLRs were significantly lower in the FasL-negative group than in the -positive group (P = 0.0182). The cause-specific survival rates of the ECOG PS 0 group were significantly higher than that of the ECOG PS > 0 group (P < 0.0001). CONCLUSIONS Our results suggest the associations of the prognosis in advanced RCC with peripheral blood NLR and FasL expression in nephrectomized tumor. The characteristics of lower values of NLR and FasL expression positivity in late-recurrence compared with other metastatic timings suggest strong host immune activity, and may imply relatively long survival. On the other hand, elucidation of the patients general condition obtained not only by chemical data but also by ECOG PS is crucial in the management of patients with advanced RCC.


International Journal of Urology | 2014

Prognostic impact of preoperative hematological disorders and a risk stratification model in bladder cancer patients treated with radical cystectomy.

Takehiro Sejima; Shuichi Morizane; Akihisa Yao; Tadahiro Isoyama; Motoaki Saito; Takashi Amisaki; Tsutomu Koumi; Atsushi Takenaka

The present study investigated prognostic indicators, including clinicopathological and preoperative hematological factors, and developed a prognostic factor‐based risk stratification model in bladder cancer patients treated with radical cystectomy.


Urologia Internationalis | 2012

Fas expression in renal cell carcinoma accurately predicts patient survival after radical nephrectomy.

Takehiro Sejima; Shuichi Morizane; Nobuyuki Hinata; Akihisa Yao; Tadahiro Isoyama; Motoaki Saito; Atsushi Takenaka

Objectives: To investigate Fas, Fas ligand (FasL) and Bcl-2 expression, which are considered to be important apoptotic regulatory factors in renal cell carcinomas (RCCs). Patients and Methods: mRNA quantification and immunohistochemistry allowed for the determination of the expression of these three factors in surgically resected tumors from 82 patients with RCC. The correlation of protein and gene expression with more than 10 years of survival data following nephrectomy (along with clinical and pathologic parameters) was analyzed using uni- and multivariate statistical models. Results: A significantly poorer outcome was observed in patients with tumors expressing high levels of Fas mRNA in the multivariate analysis (p = 0.0002). In addition, patient survival was significantly worse in FasL mRNA-positive tumor cases when compared with FasL mRNA-negative cases (p = 0.0345). Ten cases relapsed more than 5 years after nephrectomy. Among them, the tumors of 8 cases (80%) did not express FasL mRNA. Analysis of Bcl-2 did not show statistical significance of Bcl-2 expression as a prognostic indicator. Conclusions: The data suggest that pronounced Fas expression is a surrogate biomarker of active cancer cell proliferation. Given the FasL tumor counterattack theory, FasL overexpression in RCC may be one of the host immune deficiencies, consequently leading to poor prognosis.


The Journal of Urology | 2012

Detailed Histological Investigation of the Female Urethra: Application to Radical Cystectomy

Nobuyuki Hinata; Gen Murakami; Shin-ichi Abe; Masashi Honda; Tadahiro Isoyama; Takehiro Sejima; Atsushi Takenaka

PURPOSE We histologically examined the urethral anatomy to assess whether the surgical procedure for radical cystectomy should be modified in females. MATERIALS AND METHODS Anatomical and histological studies were performed on 20 adult female cadavers. Semiserial sections were processed for histological examination and immunohistochemistry. To assess the clinical value of the antegrade approach we examined blood loss and function in 12 consecutive patients who underwent radical cystectomy by this approach. RESULTS Vaginal wall smooth muscle contributed to urethral wall formation, in addition to a thin layer of proper urethral smooth muscle, particularly when the bladder detrusor was poorly developed or degenerated. The middle urethra was attached tightly to the vaginal smooth muscles with abundant veins running at the interface. The urethral sphincter and its inferoposterior continuation (urethrovaginal sphincter) were embedded in the elastic fiber rich perineal membrane. The membrane was U shaped, wrapping around the anterior aspect of the middle urethra and extending posterior along the distal vagina to end at the lateral extension of the perineal body near the external anal sphincter. Mean estimated blood loss was 965 ml. Of patients who received a neobladder hypercontinence was observed in 14.3% and 57.1% achieved continence. CONCLUSIONS There is topographical variation in the anatomy of tissues surrounding the female urethra. Care should be taken when dissecting the tissues dorsal or lateral to the urethra. The antegrade approach is useful since the urethra can be dissected under direct vision and traction can be applied to these structures.


Central European Journal of Urology 1\/2010 | 2014

Hydronephrosis after retroperitoneal laparoscopic dismembered Anderson-Hynes pyeloplasty in adult patients with ureteropelvic junction obstruction: A longitudinal analysis

Tadahiro Isoyama; Hideto Iwamoto; Seiya Inoue; Shuichi Morizane; Nobuyuki Hinata; Akihisa Yao; Masashi Honda; Takehiro Sejima; Atsushi Takenaka

Objective We evaluated the improvement of hydronephrosis longitudinally after laparoscopic dismembered Anderson–Hynes pyeloplasty in adult patients with ureteropelvic junction obstruction. Material and methods Sixteen patients underwent laparoscopic pyeloplasty at our institution between January 2006 and June 2012. Hydronephrosis was assessed by ultrasound and intravenous pyelography at 3, 6, 12, 18, and 24 months after pyeloplasty. Results The mean follow–up time was 24 months. Preoperative hydronephrosis was diagnosed as grade 2 and grade 3 in 8 patients each. Postoperative improvement of the hydronephrosis by one grade was observed in 56%, 73%, 67%, 50%, and 40% of patients at 3, 6, 12, 18, and 24 months, respectively. Improvement of the hydronephrosis by two grades was observed in 6%, 27%, 33%, 50%, and 60% of patients at 3, 6, 12, 18, and 24 months, respectively. In 5 of 12 patients (42%), hydronephrosis was still improving even after 12 months postoperatively. Conclusions Adult patients demonstrate relatively rapid improvements in the degree of hydronephrosis after laparoscopic pyeloplasty and continue to improve for a long time.


International Journal of Urology | 2013

Dry box training with three-dimensional vision for the assistant surgeon in robot-assisted urological surgery

Nobuyuki Hinata; Hideto Iwamoto; Shuichi Morizane; Katsuya Hikita; Akihisa Yao; Kuniyasu Muraoka; Masashi Honda; Tadahiro Isoyama; Takehiro Sejima; Atsushi Takenaka

We analyzed whether three‐dimensional vision, practice or previous laparoscopic experience improves the surgical performance of the bedside assistant during robot‐assisted surgery. Six experienced laparoscopic surgeons and 15 novices carried out three skills drills imitating an assistants maneuvers in robot‐assisted surgery, and times for completing the tasks were recorded. Both the novice and experienced groups showed significantly shorter manipulation times for each drill with three‐dimensional vision compared with two‐dimensional or glassless three‐dimensional vision. The experienced group showed significantly shorter manipulation times than the novice group for all types of vision. A significant improvement was observed 14 out of 18 times in the novice group, but only one out of 18 times in the experienced group. We can conclude that the use of three‐dimensional visualization facilitates the performance of the assistant surgeon, especially if a novice, during robot‐assisted surgery. Laparoscopic experience also improves the performance, whereas training is beneficial for novice assistant surgeons before carrying out actual operations.


Central European Journal of Urology 1\/2010 | 2013

Low pre-operative levels of serum albumin predict lymph node metastases and ultimately correlate with a biochemical recurrence of prostate cancer in radical prostatectomy patients

Takehiro Sejima; Hideto Iwamoto; Toshihiko Masago; Shuichi Morizane; Akihisa Yao; Tadahiro Isoyama; Hiroyuki Kadowaki; Atsushi Takenaka

Introduction To date, only few studies focusing on the issue of host general and immune activity have been performed in localized prostate cancer (PCa). The aim of this study was to elucidate potent non tumor–related biomarkers that express aggressiveness of PCa treated by radical prostatectomy (RP). Materials and methods Data from 179 patients who underwent RP were analyzed. The correlations between various kinds of non tumor–related factors in addition to tumor–related factors and biochemical recurrence (BCR) were analyzed. The correlations between pre–, intra– and post–operative factors were also analyzed. Results Thirty–two cases (17.9%) had a BCR. The factors found to be significantly predictive of BCR using a Cox–proportional hazard model were the pre–operative serum prostate specific antigen (PSA) level and the existence of pathological lymph node metastasis (LNM). A low pre–operative serum albumin level (<4.0 g/dl) was significantly correlated with BCR univariately. Logistic regression analysis revealed that a low pre–operative serum albumin level, an American Society of Anesthesiologists (ASA) score above class 2, and a Gleason score above 8 in the biopsy specimens were significantly predictive of pathological LNM. Conclusions Tumor–related characteristics are more important for predicting BCR. However, our results suggest that low pre–operative serum albumin level may indicate extensive disease of clinically localized PCa and may ultimately be correlated with BCR. Although multiple reasons may account for the significance of the serum albumin level, it is noteworthy that delayed diagnostic and therapeutic procedures in comorbid patients with low serum albumin levels may lead to PCa progression.


International Journal of Urology | 2003

Alteration of apoptotic regulatory molecules expression during carcinogenesis and tumor progression of renal cell carcinoma

Takehiro Sejima; Tadahiro Isoyama; Ikuo Miyagawa

Background: In order to characterize the alteration of apoptotic regulatory molecule expressions during carcinogenesis and tumor progression of renal cell carcinoma (RCC), we compared the expressions between tumor and normal tissues, and evaluated the relationships between expressions in tumors with pathological and clinical characteristics.

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