Biomedical subjects

R Yamada

Publications and source records attributed to R Yamada.

525 records · Page 30Linked to original sources

PubMedDate not supplied

Pharmacokinetics and radiosensitizing effect of PR-350.

PURPOSE: The in vivo pharmacokinetics and sensitizing effects of PR-350, a newly developed, highly water-soluble radiosensitizer were examined. MATERIALS AND METHODS: C3H/HeJ mice bearing SCC-VII tumor cells were used in the experiments. Results were compared with those of PR-28 and SR-2508. RESULTS: The intratumoral concentration of PR-350 reached the maximum value of 77.7 mg/kg 20 min after intravenous injection. The concentration in the brain was below the detection limit. The enhancement ratios of PR-350 calculated using the growth delay method were 0.9 for PR-350 at 50 mg/kg and 1.4 for PR-350 at 100 mg/kg, compared with 1.4 for SR-2508 at 100 mg/kg and 1.0 for PR-28 at 100 mg/kg. CONCLUSION: PR-350 and SR-2508 revealed similar sensitizing effects. The side effects of PR-350 are expected to be equal to or less than those of SR-2508. PR-350 seems to be a promising radiosensitizer.

Animals↗

PubMedDate not supplied

Development of variable dose X-ray fluoroscopic system--aimed at reduction of X-ray exposure during interventional radiologic procedure.

Recent advancement in IVR by the catheterization technique has raised the problem of increased X-ray exposure dose. To minimize this problem, we developed an X-ray fluoroscopy system with which the operator can select the X-ray dose according to the required image quality. The optical system features an optical iris that adjusts the amount of light input to the camera tube (the optical iris is usually fixed). If a rough fluoroscopic image with low S/N is acceptable, the optical iris is opened and the fluoroscopic dose is automatically reduced. This reduces exposure dose to 30-60% of the conventional dose.

Angiography↗

PubMedDate not supplied

Three-dimensional power Doppler sonography of tumor vascularity.

PURPOSE: To assess the clinical value of three-dimensional (3D) power Doppler imaging of intratumoral blood flow. MATERIALS AND METHODS: Two hepatocellular carcinomas (HCC), one renal cell carcinoma, one hepatic focal nodular hyperplasia (FNH), and one iliac bone metastasis of HCC were used. Images were collected by power mode using the GE-Yokogawa LOGIQ 700. Power Doppler images were recorded on S-VHS videotape and fed into a workstation. Flow information was then extracted, and 3D images were constructed by surface rendering. RESULTS: Preparation of 3D images could be accomplished in one minute after feeding flow information into the workstation. Intratumoral vascular structure could be easily evaluated. This 3D imaging was useful for the differential diagnosis of hepatic tumors, especially HCC and FNH, which were confirmed in 3D imaging to have distinctly different intratumoral vascular structures. CONCLUSION: 3D imaging of intratumoral blood flow was possible by 3D processing of the power Doppler images. 3D power Doppler imaging is expected to be helpful for the differential diagnosis of tumors.

Bone Neoplasms↗