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Biomedical subjects

N Amemiya

Publications and source records attributed to N Amemiya.

24 records · Page 2Linked to original sources
PubMed1989

Functional activity of protein S determined with use of protein C activated by venom activator.

A new screening procedure, an easy and specific assay for determining functional Protein S activity, has been developed, with use of Protein C activated by venom activator (Protac). Purified Protein C (100% amidolytic activity) was activated by venom activator (6 units/mL). To a mixture of 100 microL of Protein S-deficient plasma, 20 microL of sample plasma, 100 microL of cephalin (Actin), and 20 microL of activated Protein C we added 100 microL of 25 mmol/L CaCl2 solution and measured the clotting time with a KC 10 coagulometer. The functional Protein S activity correlated well with the concentrations of Protein S antigen measured by enzyme immunoassay and the Laurell rocket technique (r = 0.810 and 0.850, respectively) in normal subjects, patients with myocardial infarction undergoing warfarin therapy, and patients with liver cirrhosis.

Glycoproteins↗
PubMed1988

Amidolytic kinetic assay of protein C by selective spectrophotometry in a centrifugal analyzer.

This rapid, simple amidolytic assay of protein C activity in whole plasma involves activation by protein C activator from the venom of Agkistrodon contortrix contortrix (Protac) and use of a Cobas Fara spectrophotometer programmed for kinetic assay. Plasma is incubated with activator venom in the presence or absence of antibody to human protein C in the instrument, chromogenic substrate (S-2366) is added, and the absorbance is measured at 405 nm. The difference between the absorbance of the sample plasma with and without antibody to human protein C correlated well with protein C antigen as assayed by enzyme-linked immunosorbent assay (ELISA) and the Laurell rocket technique in normal subjects, patients being treated with warfarin, and patients with liver cirrhosis or disseminated intravascular coagulation. Our mean value for protein C in normal subjects is 115.9 (SD 16.7)% for amidolytic activity, 103.0 (SD 17.4)% for ELISA, and 97.2 (SD 18.1)% for the rocket technique. The high value for normal subjects presumably includes some nonspecific amidolytic activity activated by the activator venom, as indicated by measurable activity in immuno-depleted protein C-deficient plasma. Within-run and between-run CVs were less than 5% at low, normal, and high concentrations of protein C amidolytic activity.

Centrifugation↗
PubMed1988

[Effects of chronic oral administration of ketanserin and trichlormethiazide on blood pressure in stroke-prone spontaneously hypertensive rats].

The present study was undertaken to elucidate the effects of ketanserin and trichlormethiazide on blood pressure in stroke-prone spontaneously hypertensive rats (SHRSP). Oral ketanserin and trichlormethiazide were administered to separate groups for 4 weeks. Combined ketanserin and trichlormethiazide was also administered and the effects observed. 1) In both ketanserin and trichlormethiazide administered groups, significant antihypertensive actions were observed as compared with the non-treated SHRSP. 2) In the ketanserin administered group, a significant increase in water drinking activity was observed, accompanied with an increased urinary volume. 3) In the trichlormethiazide administered group, urinary sodium excretion decreased significantly, accompanied with an increased urinary norepinephrine excretion. 4) Combined administration of ketanserin and trichlormethiazide enhanced the decreases in blood pressure which were produced by single administration of either ketanserin or trichlormethiazide. Moreover, both the increasing tendency in the urinary sodium excretion and the decreasing tendency in the urinary norepinephrine excretion occurred after the combined administration in SHRSP. These findings suggest that ketanserin produces an antihypertensive effect and may act prophylactically for thiazide-induced renal impairment in SHRSP.

Administration, Oral↗