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Featured researches published by Osamu Yoshida.


Hypertension | 1993

High sensitivity to salt in kininogen-deficient brown Norway Katholiek rats.

Masataka Majima; Osamu Yoshida; Harue Mihara; Takeshi Muto; Susumu Mizogami; Yoshikazu Kuribayashi; Makoto Katori; Sachiko Oh-ishi

Brown Norway Katholiek rats, which have very low levels of plasma kininogens, excreted a much smaller amount of kinin in the urine than normal rats of the same strain. The systolic blood pressure of 7-week-old kininogen-deficient rats fed low (0.3%) NaCl diets (131 +/- 4 mm Hg, n = 12) was not different from that in normal rats. Two percent NaCl diets given from 7 weeks of age for 4 weeks caused rapid increases in blood pressure (167 +/- 4 mm Hg, n = 12, 9 weeks old) in deficient rats, although the same diets induced no blood pressure increase in normal rats. Urinary excretion of active kallikrein and prokallikrein remained constant in both rat groups throughout NaCl loading. During this period, the deficient rats secreted less urine (9 weeks old, P < .05) and less urinary sodium (11 weeks old, P < .05). Serum levels of sodium in deficient rats were higher (P < .05) than in normal rats at 9 weeks of age. Intracellular concentrations of sodium in the erythrocytes of deficient rats were higher (P < .05) than in normal rats throughout NaCl loading. Subcutaneous infusion of bovine low molecular weight kininogen with an osmotic pump in NaCl-loaded deficient rats induced a reduction (P < .01) in blood pressure and increases (P < .05) in urine volume and urinary sodium and kinin levels. By contrast, subcutaneous infusion of the bradykinin antagonist Hoe 140 or of aprotinin in NaCl-loaded normal rats induced a hypertensive response. This antagonist treatment reduced urine volume and urinary sodium. These results indicate that the lack of kinin generation observed in the kininogen-deficient rats was related through sodium retention to the hypertensive response to NaCl loading.


Hypertension | 2008

Nifedipine Improves Endothelial Function: Role of Endothelial Progenitor Cells

Tomonori Sugiura; Takahisa Kondo; Yasuko Kureishi-Bando; Yasushi Numaguchi; Osamu Yoshida; Yasuaki Dohi; Genjiro Kimura; Ryuzo Ueda; Ton J. Rabelink; Toyoaki Murohara

Nifedipine has been shown to improve endothelial function. Recent studies have indicated that endothelial function is correlated with the number of circulating endothelial progenitor cells (EPCs), but it is unclear whether nifedipine affects the number and function of EPCs. The aims of this study were to determine the effects of nifedipine on the number and function of EPCs and to investigate the relationship between improvement of endothelial function and EPC numbers in patients with hypertension. Stage 1 hypertensive men (n=37) were randomly divided into the nifedipine group and the control untreated group. The nifedipine group was administered slow-release nifedipine (20 mg) once daily. At baseline and after 4 weeks, flow-mediated dilation, blood pressure, biochemical data, and number of circulating CD34+CD133+ progenitor cells and EPCs were measured. The direct effects of nifedipine on EPC number and function were assessed in vitro. In the nifedipine group, flow-mediated dilation and the numbers of circulating CD34+CD133+ progenitor cells and EPCs were increased, along with a decrease of serum malondialdehyde low-density lipoprotein. The improvement of flow-mediated dilation by nifedipine was correlated with the increase of circulating CD34+CD133+ progenitor cells. Nifedipine also improved angiogenesis-related functions of EPCs (differentiation, migration, and resistance to oxidative stress) in vitro. Thus, nifedipine improved endothelial function and EPC function in stage 1 hypertensive subjects. The latter action may be mediated by reduction of oxidative stress and suppression of EPC apoptosis. These results demonstrate that nifedipine preserves endothelial integrity in patients with hypertension, at least partly, by enhancing EPC numbers and activity.


European Urology | 2000

Clinical Significance of Nonpalpable Prostate Cancer with Favorable Biopsy Features in Japanese Men

Yoshiyuki Kakehi; Toshiyuki Kamoto; Osamu Ogawa; Tetsuro Kato; Ken-ichi Tobisu; Koichiro Akakura; Shin Egawa; Michiyuki Usami; Osamu Maeda; Yoichi Arai; Yoshiteru Sumiyoshi; Yoriaki Kamiryo; Osamu Yoshida

Objective: To assess the clinical significance of nonpalpable localized prostate cancers with relatively favorable six sextant biopsy features in Japanese men.Patients and Methods: 136 nonpalpable prostate cancers of which biopsy features confined to (1) a Gleason score of 6 or less, (2) one or two positive cores per six sextant cores, and (3) 50% or less involvement of any positive core were collected. The Gleason score, tumor extension, and cancer volume were compared with preoperative serum PSA and PSA density for the patients who underwent radical prostatectomy. PSA doubling time was measured for the patients who were treated expectantly.Results: Treatments chosen for 136 patients with favorable biopsy features were radical prostatectomy alone for 48 and with preoperative androgen deprivation for 30, radiation to the prostate for 12, androgen deprivation therapy for 21, and watchful waiting for 25. Of 48 patients who underwent radical prostatectomy without androgen deprivation therapy, 25% had nonorgan–confined cancers. Seven cancers (14.6%) were Gleason score of 7, but no cancers were 8 or greater. Among 42 prostatectomy specimens for which cancer volume was measured, 22 (52.4%) had cancer volume >0.5 cm3. Pretreatment serum PSA levels were correlated neither with the Gleason score, tumor extension nor cancer volume. There was only one nonorgan–confined cancer in the 23 cancers for which PSA density was <0.2 ng/ml/g. The ability of PSA density to predict cancer volume <0.5 cm3 was 0.61 using a cut–off of 0.2 ng/ml/g. Of the 25 patients treated expectantly, the PSA doubling time was less than 2 years for 3 patients, while it was stable or fluctuated for 13.Conclusions: Tumor extension can be predicted based on PSA density in nonpalpable prostate cancer with favorable biopsy features, but predictability of cancer volume based on PSA or PSA density is not satisfactorily high. New parameters or biomarkers that complement needle biopsy findings are needed to predict clinical significance of T1c prostate cancer with favorable biopsy features.


Archive | 1992

Method for controlling current of ac servomotor

Souichi Arita; Tetsuro Kato; Osamu Yoshida; 哲朗 加藤; 修 吉田; 創一 有田


Jikken dobutsu. Experimental animals | 1990

Changes in progesterone levels in pregnancy block caused by the proximity of a strange male and by the injection of PMSG.

Sen-ichi Furudate; Osamu Yoshida; Takeshi Nakano


/data/revues/00028703/v149i1/S0002870304005009/ | 2011

The angiotensin II receptor blocker candesartan cilexetil reduces neointima proliferation after coronary stent implantation : A prospective randomized study under intravascular ultrasound guidance

Osamu Yoshida; Haruo Hirayama; Mamoru Nanasato; Toshiya Watanabe; Toyoaki Murohara


Circulation | 2008

Abstract 859: Nifedipine Improves Endothelial Function in Patinets with Hypertension: Role of Endothelial Progenitor Cells

Tomonori Sugiura; Takahisa Kondo; Yasuko Bando; Yasushi Numaguchi; Osamu Yoshida; Yasuaki Dohi; Genjiro Kimura; Toyoaki Murohara


Japanese Circulation Journal-english Edition | 2007

PE-371 Pitavastatin Ameliorates Impaired Endothelial Function in Chronic Smokers by Reducing Oxidative Stress(Smoking, The 71st Annual Scientific Meeting of the Japanese Circulation Society)

Osamu Yoshida; Takahisa Kondo; Tomonori Sugiura; Kenji Okumura; Toyoaki Murohara


Archive | 1999

CONCISE COMMUNICATIONS Virulence Characteristics of Escherichia coli in Acute Bacterial Prostatitis

Kenji Mitsumori; Akito Terai; Shingo Yamamoto; Satoshi Ishitoya; Osamu Yoshida


泌尿器科紀要 | 1996

前立腺肥大症に対する5α還元酵素阻害剤フィナステリド(MK906)の長期投与効果

Osamu Yoshida; Oishi K; Yusaku Okada; Youichi Mizutani; Yoshinori Itokawa; Tomoyoshi T; Okada K; Yosuke Komatz; Tadashi Matsuda; Hideo Takeuchi

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Koichiro Akakura

National Institute of Radiological Sciences

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