Search PubMed⌕ Search

Biomedical subjects

R Sakai

Publications and source records attributed to R Sakai.

At least 199 records · Page 11Linked to original sources
PubMed1981

Carbohydrate-binding activity of concanavalin A containing various numbers of calcium and manganese ions.

After treatment with EDTA, fragment-free concanavalin A (Con A), F3, was fractionated into three major fractions, f1, f2, and f3, by CM-cellulose chromatography. Fully metallized fragment-free Con A, F3M, was prepared by incubation of F3 with excess metal ions and also fractionated into f1M, f2M, and f3M by the same method as for F3. The Con A preparations obtained were analyzed for metal content by atomic absorption spectrophotometry and for number of carbohydrate-binding sites by ultraviolet absorbance change on binding of p-nitrophenyl alpha-D-mannopyranoside (PNP . Man) to Con A. Both f1 (Ca: 0.2, Mn: 0.1) and f1M (Ca: 0.4, Mn: 0.2) had less than 0.6 carbohydrate-binding sites per tetramer of Con A. f2 (Ca: 2.1, Mn: 0.9) and f2M (Ca: 2.1, Mn: 1.9) had 1.9 and 1.8 carbohydrate-binding sites, respectively. f3 (Ca: 4.1, Mn: 2.1) and f3M (Ca: 3.8, Mn: 4.0) had 4.1 and 4.2 carbohydrate-binding sites, respectively. Carbohydrate-binding sites of Con A were in a stoichiometric relation to bound Ca2+. The molar absorptivity change at 317 nm was 2 X 10(3) M-1 . cm-1. Precipitation activity of the above Con A preparations towards glycogen was also estimated using glycogen labeled covalently with Remazolbrilliant Blue R. The precipitation activity of Con A as well as PNP . Man-binding was strongly affected by the number of bound Ca2+. A slight contribution by Mn2+ was also detected in the precipitation activity.

Binding Sites↗
PubMed1981

Circulating immune complexes in pediatric renal allograft rejection.

Previous reports on the generation and nephritogenic capacity of post-transplant circulating immune complexes (CICs) are conflicting. To assess the pathogenicity of CICs in acute rejection (AR), 784 CIC determinations were performed on 392 serum samples from 27 pediatric renal allograft recipients using the C1q-solid phase assay (C1q-SPA) and the Raji cell radioimmunoassay (Raji-RIA). Serum samples from transplant recipients not undergoing rejection episodes and from normal subjects served as controls. Of the 784 CIC determinations, 723 (92.3%) were negative in both assays. CICs were present at some point post-transplant in eight (19.6%) recipients. Correlation of CIC levels with allograft rejection was found in only two patients with CIC levels responding to antirejection therapy; however, statistical analysis of data by chi 2 analysis failed to reveal a significant correlation of CICs with AR episodes. Allograft histology in three recipients demonstrated characteristic signs of AR. Immunofluorescent studies did not reveal significant deposition of immunoglobulin or complement. Sucrose density gradient ultracentrifugation studies confirmed the immune complex nature of materials reactive with the CIC assays. There was no immunological evidence supporting antithymocyte globulin (ATG) as an immunogen in patients demonstrating CICs post-transplant. CICs do not appear to be an important mediator of AR. Statistical analysis of data using the chi 2 test failed to reveal a positive correlation of CIC levels with AR or ultimate allograft outcome.

Antigen-Antibody Complex↗
PubMed1981

[Development of an automatic reporting system for radioimmunoassay test (author's transl)].

The system consists of a conventional RIA total system with a desk-top computer system, and a filing and reporting system of the RIA data with a flexible disk and a printer. Patient's identification is registered in the computer at the time of reception to RIA test. Their identifications are, reception date, name of RIA test, patient name, age, sex, doctor's name, name of clinical department, in- or out-patient, number of samples and it's sampling time, examination date of assay and comments included normal value. These data are recorded to a flexible disk sheet, and are combined with RIA examination data, when data process of radioimmunoassay finished. Result of the RIA test is automatically printed by the printer. Printed parameters are results of examination with standard deviation, and above described patient identifications. If necessary, time activity curves of the density are plotted too. Accurate and automatically reporting system has been applied to the routine RIA test.

Computers↗
PubMed1980

Cardiotonic effect of phthalazinol (EG-626) in the isolated guinea pig by myocardium: mechanical and electrophysiological study.

EG-626, 7-ethoxycarbonyl-6, 8-dimethyl-4-hydroxymethyl-1 (2H)-phthalazinone, was found to be a considerably potent cardiotonic agent. It produced both the positive chronotropic and inotropic actions in the guinea pig heart muscle. Positive inotropic action of isoproterenol was potentiated by EG-626 at the concentration which did not produce a substantial positive inotropic action by itself. Cardiac action potential was not modified by EG-626 at concentrations sufficient to produce positive inotropic actions. EG-626 has a strong activity to produce slow responses in the depolarized myocardium, indicating that it can increase the density of the slow channels. The possibility was shown that the increase in the density of the slow channel may play an important role in the positive inotropic action of EG-626. The increase in the intracellular cyclic AMP due to the phosphodiesterase inhibition is tentatively most likely to be the cause of the EG-626 induced in the density of the slow channels.

Adrenergic alpha-Agonists↗
PubMed1980

A study on hemodialysis leukopenia using various dialyzers.

Hemodialysis leukopenia was studied using various dialyzers and membranes. We found that dialyzers with cellulosic membranes caused marked leukopenia, but in recently developed non cellulosic membranes, its occurrence was significantly less. Additionally, our results showed a newly developed cellulose acetate membrane to correlate well with the non cellulose membranes regarding leukopenia, in spite of it being a derivative of cellulose. The extent of white blood cell decrease seemed to correlate inversely with an increase in the ultrafiltration rate per membrane area of dialyzer. The relationship between leukopenia and hypoxemia was examined also. The results of this investigation are included, however, we feel that more research is necessary before any conclusions can be made.

Cellulose↗