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Yoichi Arai

Publications and source records attributed to Yoichi Arai.

118 records · Page 7Linked to original sources
PubMed2002

The natural history of simple renal cysts.

PURPOSE: Although simple renal cysts are common in older patients, little is known concerning their natural history. We examined the natural history of renal cysts by investigating the prevalence and sequential changes in their size and number in individuals. MATERIALS AND METHODS: We collected data on 14,314 individuals who participated in a multiphasic health screening program at our institute in 1999. An ultrasound renal cyst prevalence survey was performed. As a longitudinal study, 45 patients with renal cysts were followed a mean of 6 years from January 1993 to December 1999. RESULTS: In the prevalence survey 1,700 individuals (11.9%) had at least 1 renal cyst on ultrasound. The ratio of men-to-women with cysts was 2:1. The prevalence of renal cysts increased more than 7-fold with age from 5.1% in the fourth to 36.1% in the eighth decade of life. Our longitudinal study revealed that the majority of cysts increased in size and number. The average increase in size and the rate of enlargement were 2.82 mm. and 6.3% yearly, respectively. Cysts in patients younger than 50 years grew more rapidly than those in patients 50 years old and older, at a rate of 3.94 and 1.84 mm. yearly, respectively (p = 0.010). Multiloculated cysts progressed more rapidly than simple cysts (6.93 versus 2.18 mm. yearly, p <0.0001). CONCLUSIONS: The prevalence of renal cysts increases with age and shows a remarkable difference in incidence by sex. Renal cysts progress in size and number, and appear to grow more rapidly in younger patients. The natural history of multiloculated cysts may be distinct from that of simple cysts and warrants further investigation.

Adolescent↗
PubMed2002

[Testicular sperm extraction for non-obstructive azoospermia: results with conventional and microsurgical techniques].

Testicular sperm extraction (TESE) was performed on patients with non-obstructive azoospermia using the conventional or microdissection technique. First, conventional TESE was attempted on all patients. If the sperm was retrieved successfully, the TESE procedure was terminated. Microdissection TESE was indicated only for patients for whom the conventional sperm retrieval was unsuccessful. Sperm was successfully retrieved with conventional TESE from four (24%) of 17 patients with non-obstructive azoospermia. The remaining 13 patients underwent microdissection TESE and sperm was successfully retrieved from four of them. Application of the microdissection technique resulted in an improvement in sperm retrieval rates from 24% with conventional TESE to 48% when combined with the microdissection technique. None of the patients showed any acute or chronic complications after TESE. Intracytoplasmic sperm injection (ICSI) was performed on five of the eight patients with successful sperm retrieval and the partner of four of these patients became pregnant and progressed to delivery. These results indicate the usefulness of microdissection for improving the sperm retrieval rate in men with non-obstructive azoospermia.

Adult↗
PubMed2002

[Low-dose cisplatin and UFT for hormone refractory prostate cancer].

OBJECTIVES: Biochemical modulation (BM) was initially used to enhance the effect of 5-fluorouracil (5-FU) by modulating its pharmacological action with the addition of other drugs. BM with low-dose cisplatin and 5-FU or UFT has been examined in cases of advanced gastric or pancreas cancer and 30 to 40% response rates have been reported. In the present study, the effect of BM on hormone refractory prostate cancer (HRPC) patients was examined. METHODS: BM consisting of 5 mg/body of cisplatin 3 times per week and 300-450 mg of UFT/day was given to 30 HRPC patients (median and range of age: 66 and 52-72, respectively). The ECOG performance status was 0 to 1. Gleason score was 7 in 8 patients, 8 in 10 patients and 9 in 12 patients, respectively. The metastatic site was bone in 29 patients (extent of disease on bone scan [EOD] grade 1: 10, 2: 10, 3: 8, 4: 1), lymph node in 8 and liver in 1. RESULTS: Among the 29 patients assessable for bone metastasis, 5 (17%) obtained marked improvement on bone scan. One was EOD grade 4 (super bone scan) and 4 were EOD grade 1-3. Eight (28%) were stable and 16 (55%) progressed on bone scan. Among 8 patients with lymph node metastasis, 4 (50%) showed partial response and 4 (50%) progression. One patient with liver metastasis showed complete response. Fourteen (47%) out of 30 patients showed a PSA decline of 50% or greater. Their median response duration was 8 months (range; 2 to 44 months). Among the 25 patients assessable for bone pain, 7 (28%) improved, 12 (48%) remained stable and 6 (24%) progressed. A side effect of Grade II anemia was seen in one patient. CONCLUSION: BM is effective in almost half of hormone refractory prostate cancer patients.

Adenocarcinoma↗
PubMed2002

[Laminectomy for spinal cord compression occurring in hormone refractory prostate cancer].

In many cases of advanced prostate cancer, bone metastasis frequently occurs. Androgen deprivation therapy is very effective for these cases, but this therapy would result in failure, and symptomatic metastasis would develop. Approximately eighty percent of cases with bone metastasis showed epidural metastasis. When these lesions enlarge, spinal cord compression (SCC) occurs in five to ten percent of cases. Many urologist would choose an adequate modality for this problem, based on the prognosis and/or general status of each patient. In this article we overview laminectomy for SCC and present our experience.

Aged↗
PubMedDate not supplied

Clinical significance of ST3Gal IV expression in human renal cell carcinoma.

Alteration of sialyltransferase expression has been implicated in carcinogenesis. Out of sialyltransferases cloned to date, we focused on ST3Gal IV expression in human renal cell carcinoma (RCC). Levels of ST3Gal IV mRNA were examined in human RCC in comparison with non-tumor kidney. ST3Gal IV cDNA obtained by polymerase chain reaction from cDNA library of human RCC cell line ACHN was identical to STZ in nucleotide sequence. Northern blot analysis was performed for 24 non-tumor kidney and 25 primary RCC tissues, and 5 metastases. ST3Gal IV mRNA level was decreased in 16 cases of 22 primary RCC tissues compared to 21 non-tumor kidney tissues. The mRNA level was low in 4 and equivocal in one, of 5 metastases. The 6 cases that possessed almost the same levels of ST3Gal IV mRNA in primary tumor tissues as those in non-tumor kidneys showed favorable prognoses, as assessed by Kaplan-Meier curve. These results indicate that down-regulation of ST3Gal IV mRNA may be one of the factors associated with the malignant progression of human RCC.

Adult↗
PubMedDate not supplied

Immunostaining of stage-specific embryonic antigen-4 in intratubular germ cell neoplasia unclassified and in testicular germ-cell tumors.

Stage-specific embryonic antigen-4 (SSEA-4) is expressed in testicular germ-cell tumors (GCT) according to studies using thin-layer chromatography (TLC) immunostaining. To further understand the relationship between SSEA-4 and the histogenesis of testicular GCT, we examined the expression of SSEA-4 in 43 samples of testicular GCT either by immunohistochemical staining or by TLC immunostaining. Immunohistochemical staining detected SSEA-4 in spermatogonia from the non-tumor parts of the testis and in all of 8 samples of intratubular germ cell neoplasia unclassified (IGCNU). Immunohistochemical staining was SSEA-4 positive in all 9 seminomas, and in one yolk sac tumor and in 5 embryonal carcinomas among 9 non-seminomas. Immunostaining with TLC showed that SSEA-4 was retained in 15 of 16 seminomas and in 4 of 8 non-seminomas. These results demonstrate an antigenic link between spermatogonia, IGCNU, and testicular GCT. We suggest that SSEA-4 is associated with the histogenesis of testicular GCT.

Adult↗