Biomedical subjects
S Sugiki
Publications and source records attributed to S Sugiki.
[MR diffusion-weighted imaging of cerebral infarction].
MR diffusion-weighted imaging was performed to investigate changes in water diffusion in patients with cerebral infarction, and diffusion-weighted images (DWI) were compared with T2-weighted images (T2WI). Acute and subacute infarcts were seen as areas of high intensity on DWI and showed lower apparent diffusion coefficients (ADCs), while chronic infarcts showed a relative increase in ADCs. The relative ADC increased progressively over time, becoming renormalized at 3 to 4 weeks, and was elevated in the chronic state. On DWI, infarcts as small as 5 to 6 mm in diameter and lesions adjacent to the ventricular or subarachnoid space could be readily identified. DWI was useful for distinguishing acute lesions from chronic lesions in patients with multiple cerebral infarction, and provided valuable pathophysiologic information on the course of ischemic stroke evolution.
Pharmacokinetics of human activated protein C. 1st communication: plasma concentration and excretion of a lyophilized purified human activated protein C after intravenous administration in the mouse and the rabbit.
Pharmacokinetic studies of human activated protein C (CAS 42617-41-4, APC) were investigated in mice and rabbits with 125I-labeled compound. Plasma levels of APC were determined by three different assays: total radioactivity, APC antigenicity determined by sandwich enzyme-linked immunosorbent assay (ELISA), and the amidolytic activity which was performed by immunologically captured APC. APC concentration obtained from these assays were shown to be correlated well at early times post-dose. After intravenous administration, total radioactivity in the plasma declined tri-exponentially, but antigenicity and amidolytic activity in the plasma declined biexponentially. Plasma AUC increased proportionally with the dose, and the total body clearance and t1/2 did not change significantly. In addition, no significant difference was observed between the pharmacokinetics in male and female mice. In rabbit study, the profiles of times vs APC concentration in the plasma was similar to those in mice after single bolus injection. The plasma concentrations of APC during and after infusion in rabbits were also determined. APC concentration increased during infusion and reached almost steady state at the end of infusion. The profiles of the APC concentration in benzamidine citrate plasma corresponded to the simulated curves which were characterized by the parameters obtained from the single bolus experiment. Plasma disposition profiles of the protein were studied with high performance gel chromatography method. The radioactivity in the unchanged APC was observed at 15 min after administration. At 1 h, most of the radioactivity was observed in larger molecule fraction than the intact APC. These results corresponded to the decrease of amidolytic activity in the plasma.(ABSTRACT TRUNCATED AT 250 WORDS)
[Detection of cortical infarcts in brain MR imaging: feasibility of short-TR-T2-weighted imaging using a fast spin echo sequence].
MRI of the brain using a fast SE sequence is often performed with a TR above 5000 msec, so there is a tendency for the signal of CSF to become too high. However, when cerebral atrophy is marked, small lesions of the brain parenchyma can be hard to detect. Therefore, we examined short-TR-T2-weighted images using a fast spin echo sequence. The 58 subjects included 33 men and 25 women, and cortical infarction was detected in five of them. On the short-TR-T2WI sequences, the infarct lesions were imaged as areas of higher signal intensity than cerebrospinal fluid, the signal of which was reduced. In cortical infarction cases, fluid-attenuated inversion recovery (FLAIR) images can detect the lesion more easily, but FLAIR sequences cannot be obtained with all MR equipment. Short-TR-T2WI, which readily yields images comparable to those of FLAIR, is an useful method.