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Featured researches published by Chikara Ohyama.


International Journal of Cancer | 2001

Glycolipid composition in bladder tumor: a crucial role of GM3 ganglioside in tumor invasion.

Sadafumi Kawamura; Chikara Ohyama; Ryuji Watanabe; Makoto Satoh; Seiichi Saito; Senji Hoshi; Shinsei Gasa; Seiichi Orikasa

Glycolipids were extracted from primary bladder tumors of 14 patients and 2 normal counterparts. Their expression pattern was assessed by thin‐layer chromatography (TLC). The most remarkable change was massive accumulation of GM3 in superficial bladder tumors compared with invasive tumors. This change was also confirmed by immunohistochemistry using anti‐GM3 monoclonal antibody. The activities of glycosyltransferases responsible for GM3 synthesis (GM3 synthase, Gb3 synthase and GD3 synthase) were consistent with upregulated expression of GM3 in superficial tumors. It was suggested that the marked GM3 accumulation in superficial tumors was caused not only by upregulated GM3 synthase but also by downregulated activities of Gb3 and GD3 synthase. Histopathologic examination revealed an inverse correlation of the amount of GM3 expressed with invasive potential. Exogenously supplemented GM3 suppressed invasion potential in human bladder tumor cell lines (T‐24, KK‐47). These results indicate that the amount of GM3 expressed may serve as an indicator of the invasion potential of bladder tumor. Furthermore, new antiinvasion therapeutics may be possible by administration of GM3.


Cancer | 2002

Sialosyl-Lex expression defines invasive and metastatic properties of bladder carcinoma

Kenji Numahata; Makoto Satoh; Kazuko Handa; Seiichi Saito; Chikara Ohyama; Akihiro Ito; Toshiko Takahashi; Senji Hoshi; Seiichi Orikasa; Sen-itiroh Hakomori

Two types of transitional bladder carcinoma have been distinguished based on macroscopic morphology: type A papillary carcinomas, with papillomatous surface outgrowth without infiltration into muscular layer, and type B nodular carcinomas, with a nonpapillomatous surface appearance, most of which display infiltrative growth through muscular layer, and some of which display lymphatic or blood‐borne metastasis. However, there is no specific predictor at early stages for later invasive and metastatic clinical outcome of patients with type B tumors.


The Journal of Urology | 1991

High energy underwater shock wave treatment on implanted urinary bladder cancer in rabbits

Senji Hoshi; Seiichi Orikasa; Masaaki Kuwahara; Ken-Ichi Suzuki; Kazuyuki Yoshikawa; Seiichi Saitoh; Chikara Ohyama; Makoto Satoh; Sadafumi Kawamura; Masato Nose

The effects of focused high energy shock waves (SW) on the implanted urinary bladder cancer in rabbits were examined. The bladder cancer was exposed to 2000 to 8000 shots of focused SW under ultrasound guidance. Although only focal necrosis of the tumor was seen in the one day SW exposure, wider and deeper tumor necrosis was observed in the tumors following serial SW (2000 to 6000 shots, for two to three days). Eight to 10 day serial SW exposure (6000 to 8000 shots) decreased the tumor growth in comparison with that of the control. Lung metastases examined by periodic chest X-ray after SW treatment revealed that SW did not promote lung metastases. Pathological findings were also in accord with the X-ray examinations. Polyclonal antibody type 4 collagen was used for immunohistochemical staining of vascular wall in bladder cancer. Vascular wall destruction, not found in spontaneous necrotic tumor, were clearly visible in SW induced necrotic area. SW induces vascular damage in the tumor, which may be the primary cause promoting the tumor necrosis.


The Journal of Urology | 2002

Lymphatic Mapping and Gamma Probe Guided Laparoscopic Biopsy of Sentinel Lymph Node in Patients With Clinical Stage I Testicular Tumor

Chikara Ohyama; Yutaka Chiba; Tetsuro Yamazaki; Mareyuki Endoh; Senji Hoshi; Yoichi Arai

PURPOSEnWe attempted to detect lymphatic drainage and sentinel lymph node with radioactive tracer in patients with testicular tumor. We then tried to determine if sentinel lymph node biopsy with gamma probe guided laparoscopic procedure was feasible as a staging tool for patients with clinical stage I testicular tumor.nnnMATERIALS AND METHODSnTechnetium-labeled phytate was injected around the tumor in 15 consecutive patients with clinical stage I testicular tumor. Lymphatic drainage and sentinel lymph nodes were imaged by a gamma camera. Localization of the sentinel lymph node was confirmed with a handheld gamma probe. After we confirmed that sentinel lymph nodes were detected in the initial 10 patients, gamma probe guided laparoscopic sentinel lymph node biopsy was performed after routine orchiectomy in the next 4. To confirm whether the radioactive node was really a sentinel lymph node the final patient in this series underwent laparoscopic retroperitoneal lymph node dissection with a unilateral template.nnnRESULTSnSentinel lymph nodes were detected in all patients by lymphoscintigraphy and handheld gamma probe, and each node varied. Right tumors in sentinel lymph node were detected at the inter-aortocaval, paracaval or common iliac region. Para-aortic lymph nodes were detected as sentinel lymph node in cases of left tumor. In the 4 patients who underwent gamma probe navigated laparoscopic procedure sentinel lymph nodes were easily detected and safely removed for pathological examination. In the last patient who underwent laparoscopic lymph node dissection micrometastasis was found only at the sentinel lymph node.nnnCONCLUSIONSnSentinel lymph node can be detected by lymphoscintigraphy and handheld gamma probe. Gamma probe guided laparoscopic biopsy of sentinel lymph node is technically possible. These techniques may have a role in the management of clinical stage I testicular tumor but further trials are required for establishment of the concept of sentinel lymph node in testicular tumor.


International Journal of Urology | 2000

Significance of simultaneous determination of serum human chorionic gonadotropin (hCG) and hCG-beta in testicular tumor patients.

Senji Hoshi; Ken-Ichi Suzuki; Shigeto Ishidoya; Chikara Ohyama; Makoto Sato; Takashige Namima; Seiichi Saito; Seiichi Orikasa

Background : Simultaneous determinations of human chorionic gonadotropin hormone (hCG) and hCG‐β frequently produce discrepancies, that is when hCG or hCG‐β is normal, the other is elevated. Accordingly, we examined the significance of simultaneous determination of serum hCG and hCG‐β in testicular tumors.


International Journal of Urology | 2002

Adrenal metastasis from renal cell carcinoma: Significance of adrenalectomy

Akihiro Ito; Makoto Satoh; Chikara Ohyama; Seiichi Saito; Ichiro Shintaku; Osamu Nakano; Hiroshi Aoki; Senji Hoshi; Seiichi Orikasa

Background : The present study examined adrenal metastasis resulting from renal cell carcinoma (RCC), with the aim of assessing the need for routine ipsilateral adrenalectomy during radical nephrectomy.


International Journal of Urology | 2002

Bilateral testicular tumors: A report of nine cases with long-term follow-up

Chikara Ohyama; Atsushi Kyan; Makoto Satoh; Seiichi Saito; Yosuke Nishimura; Yoshitada Imai; Katsuhiko Oikawa; Jun Yokoyama; Ken-ichi Suzuki; Mutsuo Takeuchi; Senji Hoshi; Seiichi Orikasa

Background : The incidence and clinical features of bilateral germ cell testicular tumor (GCTT) in the Japanese population are not fully characterized. We examined the incidence, clinical features, management and outcome, sexual status, hormonal environment, implication of androgen replacement, and human leukocyte antigen (HLA) typing of bilateral GCTT.


Urologia Internationalis | 1992

Glycolipid expression in prostatic tissue and analysis of the antigen recognized by antiprostatic monoclonal antibody APG1

Makoto Satoh; Yasuo Fukushi; Sadafumi Kawamura; Chikara Ohyama; Seiichi Saito; Seiichi Orikasa; Edward Nudleman; Sen-itiroh Hakamori

The expression patterns of glycolipid from prostatic hyperplasia, prostatic cancer and normal prostate tissue were observed. A further analysis of antigen recognized by mouse monoclonal antibody APG1, which was gained by immunizing glycolipids extracted from human prostate cancer, was also performed. In cancer tissue, both of the lactosyl and globoside series glycolipids were found to be generally reduced, although in the ganglioside series, GM3 and GD3 were not reduced and only the glycolipids with longer chains than GD2 were found to be reduced. These results indicated that the inhibition of sugar chain elongation, but not sialylation, was the main synthetic change occurring with carcinogenesis of the human prostate. APG1 reacted with only two bands near GM2 and GD2 of the ganglioside fraction on a thin-layer chromatography plate, but it did not react with any of the known gangliosides of the ganglioside series including GM2 and GD2. Histochemically, APG1 showed intense reaction only in frozen tissue sections of human prostate, and the reactivity decreased with the increasing grade of cancer. Therefore, this antigen was considered to be a prostate-specific and differentiated antigen reacting with nonganglioseries gangliosides.


Japanese Journal of Cancer Research | 1990

The Effect of High‐energy Underwater Shock Waves on Implanted Urinary Bladder Cancer in Rabbits

Senji Hoshi; Seiichi Orikasa; Masaaki Kuwahara; Kazuyuki Yoshikawa; Chikara Ohyama; Makoto Satoh; Sadafumi Kawamura; Masato Nose

We have examined the effects of high‐energy shock waves (HESW) on implanted urinary bladder cancer in rabbits. The bladder cancer was exposed to 2000 to 6000 shots of focused HESW under ultrasound guidance. Although only focal necrosis of the tumor was seen in the one‐day HESW exposure (2000 shots), wider and deeper necrosis was observed in the tumors following serial HESW (4000 or 6000 shots; 2 or 3 days). These results indicate that serial HESW exposure has destructive effects on implanted bladder cancer in rabbits.


International Journal of Urology | 2001

Adenocarcinoma arising from the prostatic duct mimicking transitional cell carcinoma

Chikara Ohyama; Shunichi Takyu; Kazuyuki Yoshikawa; Hiroyoshi Suzuki; Fumiaki Tezuka; Akiyuki Hasuda; Yasuo Inaba; Senji Hoshi; Seiichi Orikasa

Abstract A 71‐year‐old man was first diagnosed with primary transitional cell carcinoma of the prostate with a skip lesion on the distal urethra. The patient received three courses of intra‐arterial chemotherapy of cisplatin (CDDP) and pirarubicin (THP‐ADM) followed by a radical prostatectomy. Histopathologic examination of the prostatectomy specimen revealed adenocarcinoma invasion along the prostatic duct extending to the peripheral acini, which was diagnosed as ductal adenocarcinoma. The clinical and histopathologic features of this case are entirely different from usual adenocarcinomas of the prostate. This rare histopathologic feature should be recognized as ‘ductal carcinoma of the prostate’, to distinguish it from papillary adenocarcinoma or adenocarcinoma with endometrioid features. The patient has had no sign of recurrence 14 months after the operation. CDDP‐based chemotherapy followed by radical prostatectomy may be one of the promising therapeutic modalities for this rare entity.

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Seiichi Saito

University of the Ryukyus

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