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Biomedical subjects

Kazuto Komatsu

Publications and source records attributed to Kazuto Komatsu.

8 recordsLinked to original sources

Pathological effects of neoadjuvant hormonal therapy help predict progression of prostate cancer after radical prostatectomy.

BACKGROUND: It is not clear whether pathological changes following neoadjuvant hormonal therapy (NHT) prior to radical prostatectomy have any value as predictors of progression in prostate cancer. METHODS: We conducted a study of 100 patients with prostate cancer who underwent radical prostatectomy following NHT. We used the Japanese general rule as the criterion to assess the biochemical recurrence rate and pathological changes after NHT. RESULTS: In terms of preoperative risk factors, the probability of recurrence was significantly higher for patients with more than 20 ng/mL of pretreatment serum prostate-specific antigen (PSA) and/or a Gleason score of 7 or higher for biopsy specimens. We defined these pretreatment findings as high-risk factors. Among 65 patients with high-risk factors, patients with a post-NHT pathological effect of grade 3 according to the Japanese general rule showed no recurrence, whereas patients with a grade 0 had a poor prognosis. Patients with a PSA nadir 0.5 ng/mL or less tended to have a better prognosis. CONCLUSION: Despite preoperative high-risk factors, patients showing good pathological effects after NHT tend to have a favorable prognosis after radical prostatectomy. Therefore; assessment of the pathological effects of NHT using the Japanese general rule as the criterion proved to be useful for the prediction of biochemical recurrence.

Aged↗

Effects of adenosine triphosphate dependent potassium channel opener on bladder overactivity in rats with cerebral infarction.

PURPOSE: We evaluated the effect of the adenosine triphosphate dependent K channel opener KRN2391 (N-cyano-N' -(2-nitroxyethyl)-3-pyridinecarboximidamide methanesulfonate) (Kirin Brewery Co., Gunma, Japan) on bladder overactivity induced by middle cerebral artery occlusion. MATERIALS AND METHODS: At 7 days after implantation of a bladder catheter in male Sprague-Dawley rats a cannula for intracerebroventricular administration was implanted and the left middle cerebral artery was occluded with 4-zero monofilament nylon thread. At 22 hours after the induction of cerebral ischemia saline was infused into the bladder at a constant rate (200 microl. per minute) and a cystometrogram was obtained with the rat in the conscious state. KRN2391 (5 microl.) was administered in intracerebroventricular fashion at graded doses (0.15 to 15 microg.). RESULTS: Bladder capacity in conscious rats was significantly reduced after left middle cerebral artery occlusion. Intracerebroventricular administration of KRN2391 significantly increased bladder capacity in cerebral infarcted but not in sham operated rats. CONCLUSIONS: These results show that a adenosine triphosphate dependent K channel opener may be useful for neurogenic bladder overactivity after cerebral infarction via action on the central nervous system.

Animals↗

Case of mediastinal seminoma with testicular microlithiasis.

Testicular microlithiasis is a rare condition in which calcified concretions fill the lumina of the seminiferous tubules. We report the case of a 19-year-old Japanese man with mediastinal seminoma, normal testicular physical findings and bilateral testicular microlithiasis seen on ultrasonography. Testicular needle biopsy demonstrated multiple laminated calcifications within the seminiferous tubules without any signals of a viable germ cell tumor. To our knowledge, this is only the sixth reported case of extragonadal germ cell tumor with testicular microlithiasis.

Adult↗

High-dose chemotherapy with peripheral blood stem cell transplantation for advanced testicular cancer.

BACKGROUND: The aim of this study was to investigate the efficacy and safety of high-dose chemotherapy (HDCT) for the treatment of patients with advanced testicular cancer. METHODS: Fourteen patients were treated with high-dose carboplatin, etoposide and cyclophosphamide (with or without THP-adriamycin) followed by peripheral blood stem cell transplantation. The treatment was used for two refractory cases, a second relapse, and for consolidation after the first relapse in one case each. It was also used for nine cases as part of the first-line treatment following primary conventional-dose chemotherapy, and for one case as the first salvage for a late recurrent tumor of teratoma with malignant transformation. RESULTS: The first two patients who received intensive pretreatment with cisplatin-based chemotherapy did not respond to HDCT. The two patients who were treated with HDCT as the first or second salvage therapy achieved successful outcomes. The results for the subsequent nine patients (consisting of two with stage IIIC, five with IIIB2, one with IIB, and one extragonadal seminoma) were two progressive disease, three no change and four partial remission. Only three are alive with NED following salvage surgery. Finally, a case of teratoma with malignant transformation did not respond well to two cycles of HDCT. There were no marked adverse reactions except one episode of severe neutropenic colitis. CONCLUSIONS: The results demonstrated the limited efficacy of HDCT even in cases with a good to intermediate risk rating according to classification by the International Germ Cell Cancer Collaborative Group. Because treatment for relapse after HDCT is extremely difficult, new HDCT regimens consisting of drugs that are not used in induction chemotherapy need to be established.

Adolescent↗

Overactive bladder--experimental aspects.

Supra-pontine lesions resulting from neurological disorders such as vascular disease, Parkinson's disease, or Alzheimer type senile dementia lead to an increase in bladder activity. This is due in part to the removal at the cortical inhibitory control of the micturition center in the brain stem - i.e. the pontine micturition center (PMC) - and in part to facilitation of excitatory control. These inhibitory or excitatory controls consist of several neurotransmitter systems, including glutamate, dopamine, gamma-aminobutyric acid (GABA), and acetylcholine. Bladder overactivity caused by cerebral infarction is mediated by upregulation of N-methyl-D-aspartate (NMDA) glutamatergic and D2 dopaminergic excitatory mechanisms, and by downregulation of NMDA glutamatergic and Ml muscarinic inhibitory mechanisms in the brain. Bladder overactivity associated with Parkinson's disease is reportedly induced by a loss of input to the D1 dopaminergic receptor. Furthermore, bladder overactivity caused by Alzheimer type dementia is thought to be mediated by downregulation of M1 muscarinic inhibitory mechanisms. Development of bladder overactivity following cerebral infarction is mediated by activation of the NMDA receptor and accompanied by an increase in c-fos, zif268 and COX-2 mRNA expression in the dorsal pontine tegmentum.

Animals↗

Contribution of cerebral nitric oxide to bladder overactivity after cerebral infarction in rats.

PURPOSE: We investigated the contribution of cerebral nitric oxide to neurogenic voiding dysfunction after cerebral infarction. MATERIALS AND METHODS: The left mid cerebral artery in female Sprague-Dawley rats was occluded with 4-zero monofilament nylon thread. Bladder activity was monitored during infusion cystometrography. Time or dose dependent effects of intracerebral ventricular administration of the nonselective nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), were investigated in conscious, sham operated and cerebral infarcted rats. The selective neuronal nitric oxide synthase inhibitor 1-(2-trifluoromethylphenyl) imidazole was also administered to determine the participation of nitric oxide synthase subtypes. Cross-sectional infarct area was measured and infarct volume was calculated 12 hours after mid cerebral artery occlusion. RESULTS: Bladder capacity was reduced by 54% 30 minutes after mid cerebral artery occlusion. L-NAME significantly increased bladder capacity in a dose and time dependent manner in cerebral infarcted rats but had no effect on sham operated rats. L-NAME (50 microg./kg.) administered 3 or 5 hours after occlusion significantly increased bladder capacity. This effect of L-NAME was reversed by injecting 250 microg. L-arginine per rat, which alone did not produce any significant change in bladder capacity in cerebral infarcted rats. Administration of 1-(2-trifluoromethylphenyl) imidazole also significantly increased bladder capacity in these rats. On the other hand, 5 microg. of the nitric oxide donor FK-409 per rat reduced bladder capacity for 10 to 15 minutes. None of the drugs affected infarct volume. CONCLUSIONS: These results indicate that supraspinal nitric oxide has an important role in bladder overactivity after cerebral infarction but it does not affect normal micturition in rats. This finding suggests a central mechanism sensitive to nitric oxide for bladder overactivity after cerebral infarction.

Animals↗

A causative factor of copulatory disorder in rats following social stress.

PURPOSE: We investigated the causative role of testosterone in copulatory disorder and the expression of c-fos messenger (m)RNA in the medial preoptic area in rats after social stress. MATERIALS AND METHODS: To generate copulatory disorder rats in the experimental defeated group were attacked by residents for 10 minutes daily for 7 consecutive days (social stress). We then investigated the effect of repeat defeat on the frequency of mounting behavior and plasma testosterone levels. The effects of testosterone replacement and/or apomorphine (100 microg./kg. subcutaneously), a dopamine receptor agonist, on the frequency of mounting behavior were also studied. After experiencing social stress the brain area within the medial preoptic area was removed for analysis of c-fos and androgen receptor mRNA expression. Real-time reverse transcription-polymerase chain reaction was done to analyze gene expression. RESULTS: Rats in the defeated group showed a reduced frequency of mounting behavior and a decrease in plasma testosterone levels compared with values in control rats (p <0.01). After testosterone replacement the frequency of mounting behavior became significantly higher than that of socially stressed rat (p <0.05) but did not achieve control levels. The frequency of mounting behavior by socially stressed rats after apomorphine treatment was significantly higher than that of vehicle treated rats (p <0.05) but the frequency produced by the combination of testosterone replacement and apomorphine injection did not achieve control levels. After the social stress experience c-fos mRNA expression was significantly increased compared with that in control rats (p <0.05). The expression of androgen receptor mRNA was not affected by social stress. Testosterone replacement significantly reduced the expression of c-fos mRNA in the medial preoptic area (p <0.05). CONCLUSIONS: Our results indicate that a reduction in plasma testosterone may have a causative role in copulatory disorder induced by social stress. Changes in c-fos mRNA expression in the medial preoptic area correlated with copulatory disorder and, thus, they are suitable for monitoring that disorder.

Animals↗