Search PubMed⌕ Search

Biomedical subjects

N Yoshioka

Publications and source records attributed to N Yoshioka.

148 records · Page 9Linked to original sources
PubMedDate not supplied

Promoting effect of monosodium aspartate, but not glycine, on renal pelvis and urinary bladder carcinogenesis in rat induced by N-butyl-N-(4-hydroxybutyl)nitrosamine.

Although the incidences were relatively low, hyperplasias of the renal pelvis and the urinary bladder have been observed in Fischer-344 (F-344) rats after both sodium aspartate and glycine treatments in long-term 2-yr bioassays. In the present study, the effects of these amino acids on development of N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN)-initiated urinary lesions were investigated in male and female F-344/DuCrj rats. F-344 rats of both sexes, 6 wk old at the commencement, were given 0.05% BBN for 4 wk and then treated with one of the amino acids at a level of 5.0% in the drinking water for the following 36 wk. Proliferative lesions in the renal pelvis often associated with necrosis and mineralization were increased in the group treated with BBN followed by sodium aspartate, but not by glycine, in both sexes. The same group demonstrated higher incidences of urinary bladder tumors with increased urinary pH and sodium concentration and decreased creatinine and uric acid, but not accompanying crystallization. These results showed a clear promoting effect of sodium aspartate for urinary carcinogenesis in rats. The mechanisms of the effect on the renal pelvis and urinary bladder might be different.

Animals↗
PubMedDate not supplied

Physical characteristics of dose calibrator.

Physical characteristics of a dose calibrator CRC-30BC (Capintec, Mt. Vernon, N.Y.) was studied in the present study. We performed repeated measurements of the radioactive sample, changing its position in the well, its volume, and its radioactivity. In terms of the vertical dependence, the highest activity was obtained 7-8 cm from the bottom of the well. For axial dependence, the lowest activity was obtained at the center of the well. The sample volume, which ranged from 1 ml to 4 ml, did not have a substantial effect on the reading of the radioactivity. As long as the center of the sample remained positioned at the appropriate point in the well, the calibrator responded proportionally to the true radioactivity, which ranged from 4.625 MBq (0.125 mCi) to 592 MBq (16 mCi). The radioactive value on the dose calibrator was reliable enough to employ in quantitative evaluation when attention was paid to the position of the radioactive source.

Calibration↗
PubMedDate not supplied

Effect of recirculation of 99mTc-Sn colloid in estimating mean transit time of soft-tissue vascular anomalies by direct puncture scintigraphy: a simulation analysis.

We have reported direct puncture scintigraphy, a novel method to estimate mean transit time (MTT) of soft-tissue vascular anomaly. In the examination, 99mTc-Sn colloid is infused percutaneously into the lesion, and MTT is calculated using the time-activity curve for the lesion. Recirculation of 99mTc-Sn colloid is neglected in computing MTT, and this may cause error. The aim of this study was to assess this error by simulation analysis. Data simulating direct puncture scintigraphy were produced for lesions with various blood volumes and various blood flows, considering recirculation and blood clearance of 99mTc-Sn colloid, and MTT was estimated by the same method used in the patient examination. Although MTT was overestimated in large lesions with intermediate or long MTT, the error was small except in extremely large lesions. It was suggested that recirculation of 99mTc-Sn colloid does not cause a serious problem in the clinical use of direct puncture scintigraphy.

Arteriovenous Malformations↗