Masatsugu Iwamura
Kitasato University
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Featured researches published by Masatsugu Iwamura.
Urology | 1999
Toyoaki Uchida; Makoto Ohori; Shigehiro Soh; Takefumi Sato; Masatsugu Iwamura; Teruaki Ao; Ken Koshiba
OBJECTIVES Transurethral resection of the prostate (TURP) has become the primary method to relieve bladder outlet obstruction for patients with benign prostatic hyperplasia (BPH). Data from 3861 consecutive patients with BPH who underwent TURP from 1971 to 1996 at our hospital were retrospectively analyzed. METHODS The patients were classified into two groups comprising 1930 patients who underwent TURP from 1971 to 1985 (early group) and 1931 patients who underwent TURP from 1985 to 1996 (late group). Risk factors associated with blood transfusions and perioperative complications were analyzed in these patients. RESULTS Mortality, morbidity, and blood transfusions were noted in 5 (0.1 %), 516 (13.4%), and 507 (13.1%) patients, respectively. The blood transfusion and morbidity rates decreased over the 25-year period (P <0.001, chi-square test for trends), which was reflected in a decrease in these rates in the late group (6.1% and 9.5%, respectively) compared with those of the early group (20.2% and 17.2%, respectively). Postoperative bleeding and morbidity were closely related to prostatic gland size and operating time. The most significant differences for the risk of a blood transfusion were related to resection time, the amount of tissue resected, age, and the decade (1970s, 1980s, or 1990s) in which the surgery was performed (P <0.0005), whereas resection time was significantly correlated with morbidity (P <0.0005). As risk factors for each complication, the time of surgical resection, the decade of surgery, and the amount of tissue resected directly correlated with the incidence of extravasation and hemostatic procedures (P < or =0.003), whereas the incidence of postoperative epididymitis positively correlated with a preoperative vasectomy and a closed drainage system (P <0.0005). CONCLUSIONS Since the 1970s, the rates of blood transfusions and morbidity have decreased for patients undergoing TURP. Advances in techniques, instrumentation, and surgical and perioperative management, including anesthesia, have made TURP a relatively safe procedure, and it remains an effective means for treating patients with BPH.
Journal of Histochemistry and Cytochemistry | 1994
Masatsugu Iwamura; Per-Anders Abrahamsson; Cynthia M. Benning; Abraham T.K. Cockett; P. A. Di Sant'agnese
We used microwave (MW) oven heat treatment to unmask human androgen receptor (AR) immunostaining in formalin-fixed, paraffin-embedded tissue. Prostate tissue was used as an AR-positive control. Tissue sections were boiled in citrate buffer in a conventional MW oven for 30 min, followed by immunostaining with a validated murine monoclonal antibody (MAb), F39.4.1, raised against a peptide included in the N-terminal domain of the 100 KD human AR. AR immunostaining was localized to the nuclei of prostate secretory epithelial cells but was weak or absent in basal cells and of variable intensity in the stromal cells. Slides exposed to less than 10 min of MW heat treatment or none at all manifested no AR immunoreactivity. Tissue morphology was well preserved. Immunohistochemical determination of AR status in a wide variety of human tissues was consistent with that previously reported by others using frozen sections. MW heat treatment of tissue samples in an excellent method of localizing AR antigenicity, enabling immunohistochemical evaluation of AR status in formalin-fixed, paraffin-embedded material.
Urology | 1998
Toyoaki Uchida; Masatoshi Muramoto; Hisataka Kyunou; Masatsugu Iwamura; Shin Egawa; Ken Koshiba
OBJECTIVES To preliminarily summarize the clinical outcomes of the transrectal high-intensity focused ultrasound procedure using the prototype Sonablate (HIFU1) and the new Sonablate-200 (HIFU2) for treating symptomatic benign prostatic hyperplasia. METHODS We treated 35 and 22 patients with HIFU1 and HIFU2, respectively. Preoperative and postoperative evaluations were made using the International Prostate Symptom Score (IPSS), quality of life (QOL) data, and the results of uroflowmetry and transrectal ultrasound, and any complications were noted. RESULTS IPSS and QOL scores showed significant improvement after using both HIFU1 and HIFU2 at 3, 6, and 12 months, postoperatively (P < 0.0001 to < 0.01; Wilcoxon signed-ranks test). Maximum flow rate (8.9 to 15.5 mL/s, P < 0.001) and prostatic volume (32.2 to 22.8 mL, P < 0.01) were significantly improved at 12 months postoperatively in patients who underwent HIFU2 treatment but not in patients who underwent HIFU1. Two hematospermia and one gross hematuria in patients treated with HIFU1 and one epididymitis in a patient treated with HIFU2 were seen but no severe complications were noted. CONCLUSIONS Focused ultrasound is an effective new technology by which tissue can be destroyed at a site distant from the source of energy without damaging surrounding tissue. The clinical efficacy of HIFU2 was superior to that of the prototype HIFU1.
Urology | 2002
Akira Irie; Masatsugu Iwamura; Kazuomi Kadowaki; Asako Ohkawa; Toyoaki Uchida; Shiro Baba
OBJECTIVES To evaluate the therapeutic efficacy of bacille Calmette-Guérin (BCG) for carcinoma in situ (CIS) of the urothelium involving the upper urinary tract when the vaccine was administered by way of the bladder using vesicoureteral reflux created by a double-pigtail (DP) catheter. METHODS Thirteen upper urinary tracts of 9 patients with cytologically diagnosed CIS, with concomitant bladder CIS in 4, were treated by intravesical BCG instillation. A DP catheter was placed retrogradely, and the appearance of vesicoureteral reflux was confirmed by cystography. BCG (1 to 2 mg/mL) in a volume sufficient to fill the renal caliceal system was administered into the bladder weekly for 6 weeks. The mean follow-up was 36 months (range 8 to 97). RESULTS The voided urine cytology turned negative in all 9 patients at a mean of 86 days after the first administration of BCG. The voided urine cytology returned positive afterward in 3 patients, and positive cytology in the upper urinary tract was confirmed in 1 of 13 treated urinary tracts, which were successfully treated by another course of BCG therapy with the DP catheter. Minor adverse effects related to BCG and the DP catheter were seen in 5 patients. CONCLUSIONS BCG therapy for the CIS involving the upper urinary tract using a DP catheter might have the potential to be an effective procedure preserving renal units and could be adopted not only as an imperative, but also as an elective, treatment option.
Cancer | 1999
Masatsugu Iwamura; Weicheng Wu; Masatoshi Muramoto; Makoto Ohori; Shin Egawa; Toyoaki Uchida; Shiro Baba
Parathyroid hormone‐related protein (PTHrP) has been shown to be the principal cause of humoral hypercalcemia associated with renal cell carcinoma (RCC). Recent studies have demonstrated that the amino‐terminal region of PTHrP has growth factor‐like activities, suggesting it may play a role in the development of RCC. In this study, expression of the carboxy‐terminal region of PTHrP was assessed immunohistochemically and its significance in predicting the prognosis of RCC was studied.
Urology | 2008
Kazumasa Matsumoto; Takefumi Satoh; Akira Irie; Junichiro Ishii; Sadahito Kuwao; Masatsugu Iwamura; Shiro Baba
OBJECTIVES Tissue-specific expression is of key importance in gene therapy and can be achieved by using tissue-specific promoters to drive therapeutic gene expression. The uroplakin (UP) promoter is a powerful tool for bladder cancer gene therapy, but the role of UP protein in the bladder remains unknown. This study aimed to detect UP III expression in transitional cell carcinoma (TCC) of the bladder and to determine whether the role of UP III heterogeneity is associated with predicting disease recurrence and patient survival. METHODS Immunohistochemical staining for UP III was carried out in 92 archival radical cystectomy and 38 normal specimens and correlated with pathologic features and clinical outcomes. RESULTS UP III expression was significantly decreased in bladder cancer tissues compared with normal controls (P <0.0001). Loss of UP III expression was associated with high-grade, muscle-invasive cancer, lymphovascular invasion (P <0.01), and decreased cancer-specific survival at a median follow-up of 25.3 months (P = 0.04). When adjusted for the effects of standard pathologic features, only lymph node metastases were associated with bladder cancer progression (P = 0.01) and mortality (P = 0.04). CONCLUSIONS Loss of UP III expression is associated with established markers of biologically aggressive bladder cancer such as lymphovascular invasion, pathologic stage, and grade. UP III expression has limited prognostic value in patients with bladder TCC, but gene therapy viral vectors driven by the UP promoter would drive therapeutic gene expression in high-UP-expressing TCC cells, but not in aggressive low-UP-expressing TCC cells.
Cancer | 2009
Takefumi Satoh; Masaki Kimura; Kazumasa Matsumoto; Ken-ichi Tabata; Hiroshi Okusa; Hideharu Bessho; Masatsugu Iwamura; Hiromichi Ishiyama; Kazushige Hayakawa; Shiro Baba
Androgen‐deprivation therapy (ADT) decreases bone mineral density (BMD) and increases fracture risk in patients with prostate carcinoma. The authors investigated the effectiveness of a single infusion of zoledronic acid initiated subsequent to ADT on BMD with hormone‐naive prostate carcinoma.
International Journal of Urology | 2007
Kazumasa Matsumoto; Akira Irie; Takefumi Satoh; Miyoko Okazaki; Masatsugu Iwamura; Shiro Baba
Objectives: We report that a combination of gemcitabine and paclitaxel will effectively treat patients with advanced urothelial carcinoma (UC) who have been previously treated with methotrexate, vinblastine, adriamycin, and cisplatin (MVAC). The objective of this study was to assess the tumor responses, toxicity, and overall survival of these patients as second‐line treatment.
International Journal of Urology | 1995
Toyoaki Uchida; Eiji Yokoyama; Masatsugu Iwamura; Ken Koshiba; Akito Terai; Toshiro Terachi; Kenji Ohishi; Osamu Yoshida
Background:
Pulmonary Medicine | 2012
Ken-ichi Tabata; Yuzuru Niibe; Takefumi Satoh; Hideyasu Tsumura; Masaomi Ikeda; Satoru Minamida; Tetsuo Fujita; Daisuke Ishii; Masatsugu Iwamura; Kazushige Hayakawa; Shiro Baba
Purpose. To retrospectively evaluate the clinical significance of radiotherapy for oligometastases of bone in prostate cancer (PCa). Methods and Materials. Between 2003 and 2008, 35 PCa patients with oligometastases of bone were treated with radiotherapy. Results. The median radiotherapy dose was 40 Gy. The 3-year overall survival rates for all patients, for patients that received a radiotherapy dose of ≥40 Gy (n = 21) and for those that received <40 Gy (n = 14), were 77.2%, 90.5%, and 50.0%, respectively. Fourteen out of 16 patients (87.5%) who had pain were improved 1 month after radiotherapy. The median duration of pain relief was 12 months. Pathological fracture and spinal cord compression (SCC) were not seen at the treated sites but developed at nonirradiated sites in three patients (8.6%) and in one patient (2.8%), respectively. Although the high-dose group (≥40 Gy) achieved better survival than the low-dose group (<40 Gy), it was not independent prognostic factor in multivariable analysis. Conclusions. Radiotherapy of bone oligometastases in PCa was effective for long-term pain relief. Pathological fracture and SCC were not seen at the treated sites. A larger clinical trial is warranted to study the actual benefit following radiotherapy for oligometastases of bone in PCa.