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Featured researches published by Yusaku Okada.


The Journal of Urology | 1996

Urinary Calculi as a Late Complication of the Indiana Continent Urinary Diversion: Comparison with the Kock Pouch Procedure

Akito Terai; Tomohiro Ueda; Yoshiyuki Kakehi; Toshiro Terachi; Yoichi Arai; Yusaku Okada; Osamu Yoshida

PURPOSE Although urinary calculi have been frequent late complications of the Kock continent urinary diversion, they have not been regarded as significant problems in patients with the Indiana pouch because of the lack of foreign material present. However, stones developed in a significant percentage of our patients with an Indiana pouch. We investigated the characteristics of stone formation in patients with the Indiana pouch and compared them to those with a Kock pouch. MATERIALS AND METHODS Detailed clinical courses regarding stone formation were reviewed in 72 patients with a Kock pouch and 54 with an Indiana pouch who had a minimum followup of 12 months. RESULTS Stones developed in 7 of 54 patients (12.9%) with an Indiana pouch compared to 31 of 72 (43.1%) with a Kock pouch. The incidence gradually increased with longer followup but it was lower in the Indiana than in the Kock pouch group (5-year stone-free rate 84% versus 66%, respectively). Although the stones consisted principally of a mixture of struvite, carbonate apatite and ammonium hydrogen urate, variable amounts of calcium oxalate were identified in 50% of the Indiana pouch calculi. CONCLUSIONS Not only urinary infections but also metabolic factors were considered to be involved in stone formation within the Indiana pouch. However, the substantially higher rate of stone formation in our Kock and Indiana pouch groups than has been reported in the United States suggested that no or infrequent pouch irrigations in our patients were important risk factors for urinary calculi.


The Journal of Urology | 1996

Psychosocial Aspects in Long-Term Survivors of Testicular Cancer

Yoichi Arai; Mutsushi Kawakita; Hida S; Toshiro Terachi; Yusaku Okada; Osamu Yoshida

PURPOSE We assessed the psychosocial well-being in cured testicular cancer patients who had undergone chemotherapy with or without retroperitoneal lymph node dissection, radiotherapy or surveillance therapy. MATERIALS AND METHODS The sample consisted of 83 cured testicular cancer patients of whom 34 had undergone cisplatin-based combination chemotherapy with or without retroperitoneal lymph node dissection (chemotherapy group), 42 had received infradiaphragmatic radiotherapy (radiotherapy group) and 7 had received surveillance therapy (surveillance group). The questionnaire reported demographic data, psychosocial well-being, working ability, satisfaction with life, relationships, and general health and fitness. RESULTS For questions dealing with psychological distress there were no differences among the groups. However, a significant number of patients in all groups reported greater feelings of anxiety about health and future since treatment. Working ability was significantly better in the chemotherapy and radiotherapy groups than in the surveillance group (p < 0.05 and p < 0.01, respectively). Interestingly, the patients who received the most extensive treatment (chemotherapy plus retroperitoneal lymph node dissection) reported the best working ability. Using the satisfaction with life scale, patients in the chemotherapy and radiotherapy groups showed significantly higher scores than those in the surveillance group (p < 0.05). The majority of the patients reported no significant change in long-term relationships with family, friends and spouse. CONCLUSIONS The development of psychosocial problems during long-term adjustment seems to be low regardless of treatment received. Although a significant number of patients reported a higher incidence of anxiety and depression since the illness, the overall attitude was positive toward life. With regard to treatment type, patients in the chemotherapy and radiotherapy groups had better working ability and greater satisfaction with life than the surveillance group.


The Journal of Urology | 1995

Effect of Urinary Intestinal Diversion on Urinary Risk Factors for Urolithiasis

Akito Terai; Yoichi Arai; Mutsushi Kawakita; Yusaku Okada; Osamu Yoshida

We investigated the effect of urinary intestinal diversion on risk factors for calcium urolithiasis, such as calcium, phosphate, magnesium, uric acid, oxalate and citrate, in 3 groups of patients (Kock pouch, Indiana pouch and ileal conduit). Mean urinary volume was not significantly different among the 3 groups. Mean serum creatinine and 24-hour creatinine clearance in the continent reservoir group were better than in the ileal conduit group. Mean urinary excretion of calcium, phosphate and magnesium was significantly greater in the continent reservoir group than in the ileal conduit group. Although calcium excretion had a positive correlation with 24-hour creatinine clearance, calcium excretion per ml. per minute creatinine clearance still showed a significant difference. Increased calcium excretion is considered to reflect metabolic disturbances resulting from reabsorption of urinary solutes through the intestinal segments. Overall, there was no significant difference in the urinary parameters between the Kock and Indiana pouch groups. While mean urinary oxalate and citrate were within the normal range in all 3 groups, more than a third of the patients in each group were hypocitraturic (less than 100 mg. per day). In none of the 3 groups did the levels of urinary calcium, phosphate and magnesium, as well as other urinary risk parameters show any correlation with the duration of diversion. In summary, our study indicated that the continent urinary reservoir causes a long-term increase in urinary excretion of calcium, phosphate and magnesium. These urinary metabolic alterations might promote the formation of calcium urolithiasis as well as infectious stones. The degree of metabolic alterations may be greater with a continent reservoir than with an ileal conduit.


The Journal of Urology | 1993

Long-term followup of the Kock and Indiana pouch procedures.

Yoichi Arai; Mutsushi Kawakita; Toshiro Terachi; Oishi K; Yusaku Okada; Hideo Takeuchi; Osamu Yoshida

Between 1984 and 1991, 115 consecutive patients underwent cutaneous continent urinary diversion comprising 76 Kock and 39 Indiana pouch procedures. The 2 different forms of achieving continent urinary diversion were subsequently compared in a long-term followup that evaluated complications, including pouch function and the need for revisions. In the Kock pouch group there were 14 (18.4%) early postoperative complications (3 months), which required 4 subsequent reoperations (5.3%). The Indiana pouch group had a similar incidence of early complications (17.9%) but there were no reservoir related problems. The long-term study group comprised 68 Kock and 37 Indiana pouch patients who were observed for 12 months or longer (mean followup 53 and 34 months, respectively). Of 9 efferent nipple valve malfunctions observed in the Kock pouch group 5 required surgical revision. Of 16 complications related to afferent limb function 15 were caused by the use of polyester fiber fabric for the anchoring collar and 8 of these 15 complications required surgical revision. The first 2 Indiana pouch patients had pouch deformities due to incomplete detubularization of the cecum that required surgical repair. Overall, surgical revisions, including minor repairs, were performed on 15 Kock pouch patients (22.1%) and 4 Indiana pouch patients (10.8%). Both forms of the procedure preserved continence to a satisfactory degree. Urinary tract stones developed in 18 patients (26.5%) from the Kock pouch group, usually on the exposed staples or the eroded, nonabsorbable collar used to construct the nipple valves. Stone formation was rare (5.4%) in the Indiana pouch group. The incidence of ureteral implantation stricture was low in both procedures. There was no significant difference in the incidence of bacteriuria between the 2 methods of urinary diversion. These data demonstrate that the Kock pouch and Indiana pouch procedures can be accomplished with the same early postoperative complication rate. Our 8-year experience showed a high incidence of Kock afferent nipple valve malfunction. However, most of these malfunctions were due to the use of a nonabsorbable collar and can be avoided. When taking this into account, therefore, it can be concluded that the Indiana pouch functions as well as the Kock pouch with roughly the same incidence of late complications and the same reoperation rate but with a lower incidence of stone formation.


Cancer | 1997

Expression of platelet‐derived endothelial cell growth factor in bladder carcinoma

Youichi Mizutani; Yusaku Okada; Osamu Yoshida

Angiogenesis is a prerequisite to cancer growth and metastasis and is induced by a variety of angiogenic factors, including platelet‐derived endothelial cell growth factor (PDECGF). The authors investigated the expression of PDECGF in 58 initial primary bladder carcinomas.


The Journal of Urology | 1996

Bone Demineralization Following Urinary Intestinal Diversion Assessed by Urinary Pyridinium Cross-Links and Dual Energy X-Ray Absorptiometry

Mutsushi Kawakita; Yoichi Arai; Chohei Shigeno; Akito Terai; Yusaku Okada; Hideo Takeuchi; Junji Konishi; Osamu Yoshida

PURPOSE We investigated the acid-base balance and bone mineral status in patients with 3 types of urinary intestinal diversion. MATERIALS AND METHODS Of 46 men with urinary intestinal diversions 20 had a Kock pouch, 15 had an Indiana pouch and 11 had an ileal conduit. Acid-base balance was assessed by arterial blood gas analysis. Bone mineral status was measured by urinary pyridinium cross-links and dual energy x-ray absorptiometry. In addition, urinary deoxypyridinoline was measured in 79 patients. RESULTS Of the 46 patients 7 (15%) with the Kock pouch (1), Indiana pouch (5) and ileal conduit (1) had metabolic acidosis associated with significantly lower bone mineral densities (p < 0.05) and higher urinary pyridinium cross-links (p < 0.005) than did those with normal acid-base status. No difference was found in metabolic acidosis and bone demineralization among the 3 groups. Additionally, in 79 patients urinary deoxypyridinoline reached the highest level immediately postoperatively and then gradually decreased to the stable level within 1 or 2 years. CONCLUSIONS Metabolic acidosis following urinary intestinal diversion results in bone demineralization. The types of diversion did not cause differences in metabolic acidosis and bone resorption. Bone has a major role in buffering acid overload in the early postoperative period.


International Journal of Urology | 1997

QUALITY OF LIFE SURVEY OF URINARY DIVERSION PATIENTS : COMPARISON OF CONTINENT URINARY DIVERSION VERSUS ILEAL CONDUIT

Yusaku Okada; Oishi K; Yasumasa Shichiri; Yoshiyuki Kakehi; Akikazu Hamaguchi; Tadao Tomoyoshi; Osamu Yoshida

Background Continent urinary reservoirs (CUR) have become one of the major options for patients requiring urinary diversion to improve their quality of life (QOL). To assess whether CUR enhanced postoperative QOL, we surveyed patients with CUR and ileal conduit (IC) using a questionnaire sent by mail.


The Journal of Urology | 1992

Papillary Adenocarcinoma in a Seminal Vesicle Cyst Associated with Ipsilateral Renal Agenesis: A Case Report

Yusaku Okada; Hirosato Tanaka; Hideo Takeuchi; Osamu Yoshida

Cysts and tumors of the seminal vesicle are uncommon, and their coexistence is extremely rare. We report a case of multiple papillary tumors inside a seminal vesicle cyst associated with ipsilateral renal agenesis in a 17-year-old man. Surgical excision of the cyst and tumors was performed without any morbidity and histology revealed well differentiated papillary adenocarcinoma.


The Journal of Urology | 1997

Strong Correlation of Basement Membrane Degradation With P53 Inactivation and/or MDM2 Overexpression in Superficial Urothelial Carcinomas

Enver Özdemir; Yoshiyuki Kakehi; Hiroshi G. Okuno; Tomonori Habuchi; Yusaku Okada; Osamu Yoshida

PURPOSES We investigated the relationships between the degradation of basement membrane underlying superficial urothelial carcinomas, including carcinoma in situ and the functional p53 loss caused by inactivation of p53 and the overexpression of mdm2 oncoprotein. MATERIALS AND METHODS Nuclear accumulations of p53 and mdm2 were examined immunohistochemically for 60 transitional cell carcinomas (primary lesions) and 13 accompanying (concomitant) carcinoma in situ lesions. Degradation of the basement membrane was defined as the reduction or total loss of type IV collagen expression. Whether there was up-regulation of MMP-1, MMP-2, and MMP-9 was analyzed immunohistochemically. RESULTS The frequency of the degradation of basement membrane underlying grade 1 pTa tumors was 0%, grade 2-3 pTa tumors 57.1%, and primary CIS lesions 83.3%. Nuclear over-accumulation of p53 was found in 48.3% and of mdm2 in 23.3% of the primary tumors. In pTa-pT1 carcinomas, nuclear staining of p53, mdm2, or both was highly correlated with degradation of the basement membrane underlying carcinomas (p = 0.00002). In the CIS lesions, the association of p53 nuclear staining with the destruction of type IV collagen expression was of borderline significance (p = 0.03). When mdm2 overexpression was considered as a molecular abnormality together with p53 inactivation, the correlation with the degradation of the basement membrane was highly significant (p = 0.00006). Moreover, the functional p53 loss was strongly associated with the up-regulation of matrix metalloproteinases (MMPs) (p = 0.0005). This finding was well correlated with the strong association of basement membrane degradation with up-regulation of MMPs (p = 0.000004). CONCLUSIONS Degradation of basement membranes underlying superficial carcinomas or CIS of the urothelium was significantly related to p53 inactivation, mdm2 overexpression, or both. The expression status of mdm2 should provide better information about the progression of superficial urothelial carcinomas than the status of p53 alone.


International Journal of Urology | 1996

Intracorporeal Lithotripsy with the Swiss Lithoclast

Akito Terai; Hideo Takeuchi; Toshiro Terachi; Mutsushi Kawakita; Yusaku Okada; Hiroshi Yoshida; Yoshiaki Isokawa; Yoji Taki; Osamu Yoshida

Background: In addition to currently available modalities of intracorporeal lithotripsy (ultrasonic, electrohydraulic, and laser), a new ballistic lithotriptor known as the Swiss Lithoclast has recently gained attention. This study reports our experience with the Swiss Lithoclast in the endoscopic management of urinary calculi.

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Osamu Yoshida

Shiga University of Medical Science

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Youichi Mizutani

Kyoto Prefectural University of Medicine

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