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Dive into the research topics where Genya Nishikawa is active.

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Featured researches published by Genya Nishikawa.


International Journal of Antimicrobial Agents | 2013

Prostatic penetration of meropenem in humans, and dosage considerations for prostatitis based on a site-specific pharmacokinetic/pharmacodynamic evaluation

Genya Nishikawa; Kazuro Ikawa; Kogenta Nakamura; Yoshiaki Yamada; Kenji Zennami; Kenji Mitsui; Masahiro Narushima; Kayo Ikeda; Norifumi Morikawa; Makoto Sumitomo

The aims of this study were to investigate the penetration of meropenem (MER) into human prostate tissue and to assess MER regimens for prostatitis by performing a site-specific pharmacokinetic/pharmacodynamic evaluation. Patients with prostatic hypertrophy (n=49) prophylactically received a 0.5-h infusion of MER (250 mg or 500 mg) before transurethral resection of the prostate. MER concentrations in plasma (0.5-5h) and prostate tissue (0.5-1.5h) were measured chromatographically. Concentration data were analysed pharmacokinetically with a three-compartment model and were used to estimate the drug exposure time above the minimum inhibitory concentration for bacteria (T>MIC, % of 24h) in prostate tissue, an indicator for antibacterial effects at the site of action. The prostate tissue/plasma ratio was 16.6% for the maximum drug concentration and 17.7% for the area under the drug concentration-time curve, irrespective of the dose. Against MIC distributions for clinical isolates of Escherichia coli, Klebsiella spp. and Proteus spp., 500 mg once daily achieved a >90% probability of attaining the bacteriostatic target (20% T>MIC) in prostate tissue, and 500 mg twice daily achieved a >90% probability of attaining the bactericidal target (40% T>MIC) in prostate tissue. However, against the Pseudomonas aeruginosa isolates, none of the tested regimens achieved a >90% probability of attaining the bacteriostatic or bactericidal targets.


Oncology Reports | 2011

Lactate dehydrogenase, Gleason score and HER-2 overexpression are significant prognostic factors for M1b prostate cancer

Yoshiaki Yamada; Kogenta Nakamura; Shigeyuki Aoki; Motoi Tobiume; Kenji Zennami; Yoshiharu Kato; Genya Nishikawa; Takahiko Yoshizawa; Youko Itoh; Akiko Nakaoka; Eri Yoshida; Tomoe Uchiyama; Nobuaki Honda

It has not been elucidated whether certain types of M1b prostate cancer (M1b PC) are associated with a poor outcome. The present study retrospectively identified predictive factors related to the outcome of M1b PC. The subjects were 104 patients who attended our hospital and received a diagnosis of M1b PC. The observation period ranged from 4 to 122 months (median, 43 months). The parameters investigated were: T classification, N classification, Gleason score (GS), pretreatment prostate-specific antigen (PSA) level, extent of disease (EOD) grade, alkaline phosphatase (ALP), lactate dehydrogenase (LDH), calcium, and hemoglobin (Hb) levels, platelet count, and the status of HER-2 overexpression as determined with a Hercep Test(TM) Kit using initial needle biopsy specimens for diagnosis. Log-rank test and Cox univariate analysis identified the following factors with statistically significant differences: pretreatment PSA ≥ 192, N1, GS ≥ 8, EOD grade 3+4, high LDH, high ALP, low Hb, and HER-2 overexpression. Multivariate Cox proportional hazard analysis identified the factors GS ≥ 8, high LDH, and HER-2 overexpression with significant differences. The hazard ratio was 5.962, 2.465, and 2.907, respectively, and the probability value was P=0.0218, P=0.0207 and P=0.0090, respectively. When the subjects with GS ≥ 8, high LDH, and HER-2 over-expression were classified as the high-risk group, the 5-year cause-specific survival rate was 51.2, 29.6, and 20.0%, respectively. The present study showed that M1b PC patients with GS ≥ 8, high LDH, and HER-2 overexpression have a very poor outcome and thus, should be treated as a high-risk group requiring close follow-up.


Journal of Chemotherapy | 2012

Determination of doripenem penetration into human prostate tissue and assessment of dosing regimens for prostatitis based on site-specific pharmacokinetic–pharmacodynamic evaluation

Kogenta Nakamura; Kazuro Ikawa; Yoshiaki Yamada; Maki Arakawa; Kenji Zennami; Genya Nishikawa; Kayo Ikeda; Norifumi Morikawa; Nobuaki Honda

Abstract Prostatic hypertrophy patients prophylactically received a 0·5-hour infusion of doripenem (250 or 500 mg) before transurethral resection of the prostate. Doripenem concentrations in plasma and prostate tissue were measured chromatographically, and analysed pharmacokinetically using a three-compartment model. The approved doripenem regimens were assessed based on the time above the minimum inhibitory concentration for bacteria (T>MIC, % of 24 hours), an indicator for antibacterial effects, at the prostate. The prostate tissue/plasma ratios were 17·3% for the maximum drug concentration and 18·7% for the area under the drug concentration–time curve, and they were irrespective of the dose. Against Escherichia coli and Klebsiella species isolates, 500 mg once daily achieved a >90% probability of attaining the bacteriostatic target (20% T>MIC) in prostate tissue, and 500 mg twice daily achieved a >90% probability of attaining the bactericidal target (40% T>MIC) in prostate tissue.


Journal of Medical Case Reports | 2011

Inflammatory pseudotumors of the kidney and the lung presenting as immunoglobulin G4-related disease: a case report

Genya Nishikawa; Kogenta Nakamura; Yoshiaki Yamada; Takahiko Yoshizawa; Yoshiharu Kato; Remi Katsuda; Kenji Zennami; Motoi Tobiume; Shigeyuki Aoki; Tomohiro Taki; Nobuaki Honda

IntroductionIt has been reported that immunoglobulin G4-related systemic disease can spread to nearly every organ, and often presents as an inflammatory mass or masses at those sites. In the kidney, this disease is often diagnosed after a radical or partial nephrectomy following the discovery of an inflammatory mass which is often suspected to be a malignant tumor. Here, we present a rare case of inflammatory pseudotumors of the kidney and the lung presenting as immunoglobulin G4-related disease, which were diagnosed by computed tomography-guided biopsies.Case presentationA 54-year-old Japanese man was referred to our hospital with suspected bilateral renal cancer, multiple lung metastases and autoimmune pancreatitis. His serum immunoglobulin G4 level was high. We used computed tomography-guided biopsies and histopathological examinations of the biopsied specimens to diagnose the tumors as immunoglobulin G4-related bilateral renal and lung inflammatory pseudotumors. Our patient was treated with oral prednisolone, and after one month of treatment, contrast-enhanced computed tomography demonstrated a general improvement, as noted by a reduction in size of the masses.ConclusionRenal masses that are formed due to immunoglobulin G4-related disease require comprehensive diagnosis to prevent unnecessary surgical resections from being performed. Further consideration should be paid to immunoglobulin G4-related diseases in the future.


BMC Urology | 2010

A rare case of metastatic renal carcinoid

Yoshiharu Kato; Kogenta Nakamura; Yoshiaki Yamada; Genya Nishikawa; Takahiko Yoshizawa; Kenji Zennnami; Remi Katsuda; Motoi Tobiume; Shigeyuki Aoki; Tomohiro Taki; Nobuaki Honda

BackgroundCarcinoid is an endocrine cell tumor with low-grade atypia, which is generally a low-grade malignant cancer with a good prognosis. Metastatic renal carcinoid is even rarer than primary carcinoids.Case presentationWe present our experience of a patient with metastatic renal carcinoid from the gastrointestinal tract.ConclusionsThe carcinoid tumor of the kidney in our patient, who had a history of liver metastasis from rectal carcinoid, was considered metastatic based on the pathological findings.


The Prostate | 2011

Significant prognostic factor of immunohistochemical HER-2 expression using initial prostate biopsy specimens with M1b prostate cancer.

Motoi Tobiume; Yoshiaki Yamada; Kogenta Nakamura; Shigeyuki Aoki; Kenji Zennami; Yoshiharu Kato; Genya Nishikawa; Toyoharu Yokoi; Nobuaki Honda

We examined whether human epidermal growth factor‐2(HER‐2) overexpression could be a useful marker of outcome after hormone therapy in patients with M1b prostate cancer (PC).


BMC Urology | 2011

Treatment of upper urinary tract stones with extracorporeal shock wave lithotripsy (ESWL) Sonolith vision

Kogenta Nakamura; Motoi Tobiume; Masahiro Narushima; Takahiko Yoshizawa; Genya Nishikawa; Yoshiharu Kato; Remi Katsuda; Kenji Zennami; Shigeyuki Aoki; Yoshiaki Yamada; Nobuaki Honda; Makoto Sumitomo

BackgroundThe aim was to retrospectively assess the results of treatment of upper urinary tract stones with the Sonolith vision manufactured by EDAP, and purchased in 2004.MethodsThe subjects were 226 Japanese patients who underwent extracorporeal shock wave lithotripsy (ESWL) alone as an initial treatment and could be followed up for at least 3 months, selected from 277 candidate patients who underwent this therapy between 2004 and 2006. Treatment effect was evaluated by kidney, ureter, and bladder X-ray or renal ultrasonography at 1 and 3 months after treatment. A stone-free status or status of stone fragmentation to 4 mm or smaller was considered to indicate effective treatment.ResultsAt 3 months after treatment, the stone-free rate was 69.4% and the efficacy rate was 77.4% for renal stones, while these rates were 91.5 and 93.3%, respectively for ureteral stones. Assessment of treatment effect classified by the location of stones revealed a stone-free rate of 94.6% and an efficacy rate of 94.6% for lower ureteral stones (4.0 mm or smaller, 1 subject; 4.1-10.0 mm, 31 subjects; 10.1-20.0 mm, 5 subjects: number of treatment sessions, 1 or 2 sessions [mean: 1.03 sessions]). Complications of this therapy included renal subcapsular hematoma and pyelonephritis in 1 case each.ConclusionsESWL with the Sonolith vision manufactured by EDAP produced a treatment effect equivalent to those achieved with other models of ESWL equipment. ESWL seems to be an effective first-line treatment also in patients who have lower ureteral stones 10 mm or larger but do not wish to undergo TUL, if measures such as suitable positioning of the patient during treatment are taken.


International Journal of Urology | 2016

Optimal method for measuring tumor extent in needle biopsy specimens to identify small-volume prostate cancer.

Keishi Kajikawa; Kent Kanao; Ikuo Kobayashi; Genya Nishikawa; Takahiko Yoshizawa; Yoshiharu Kato; Masahito Watanabe; Kenji Zennami; Kogenta Nakamura; Makoto Sumitomo

To compare various methods for measuring tumor extent in prostate biopsy specimens to identify small‐volume prostate cancer.


International Journal of Urology | 2018

Impact of a novel biopsy instrument with a 25‐mm side‐notch needle on the detection of prostate cancer in transrectal biopsy

Kent Kanao; Keishi Kajikawa; Ikuo Kobayashi; Shingo Morinaga; Hiroyuki Muramatsu; Genya Nishikawa; Masahito Watanabe; Kenji Zennami; Kogenta Nakamura; Makoto Sumitomo

To evaluate the impact of a novel biopsy instrument that extends the length of the side‐notch on the detection of prostate cancer in transrectal needle biopsy.


The Journal of Urology | 2017

MP43-14 UTILITY OF A NOVEL BIOPSY INSTRUMENT WITH LONG SIDE-NOTCH NEEDLE IN THE SELECTION OF PATIENTS FOR ACTIVE SURVEILLANCE

Kent Kanao; Keishi Kajikawa; Ikuo Kobayashi; Hiroyuki Muramatsu; Shingo Morinaga; Hiroshi Saiki; Genya Nishikawa; Yoshiharu Kato; Masahito Watanabe; Kogenta Nakamura; Makoto Sumitomo

Fig 1). After adjustment for confounders, the difference in bRFS between groups was no longer significant (HR 1⁄4 0.77; 95% CI, 0.41 to 1.46). CONCLUSIONS: AS patients that are reclassified to grade group 2 and above have a higher bRFS after surgery as compared to those undergoing IRP with similar grade disease. These differences are likely due to selection criteria for AS. Our findings help inform patient decisions regarding the risk of entering an AS program.

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Yoshiharu Kato

Aichi Medical University

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Ikuo Kobayashi

Aichi Medical University

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Kenji Zennami

Aichi Medical University

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Kent Kanao

Aichi Medical University

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