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Biomedical subjects

S Oka

Publications and source records attributed to S Oka.

At least 469 records · Page 26Linked to original sources
PubMed1983

Biorheological aspect in relation to endoendothelial fibrin lining.

In connection with the findings of Copley et al. on the reduction of the apparent viscosity of blood, plasma and serum in contact with fibrin, a theoretical analysis of a Newtonian flow through a fibrin-coated tube was developed, taking into account the electric double layer between the fibrin layer and blood. the Gouy-Chapman model for the diffuse double layer was introduced instead of the Helmholtz model. It is shown that the reduction of the apparent viscosity is governed by an "electric double layer parameter" a, which is proportional to the term sigma'zeta/R. zeta is the zeta potential, R is the radius of the tube, and sigma' is the positive surface charge density corresponding to the fixed negative density on the fibrin layer.

Blood Viscosity↗
PubMed1983

Purification and characterization of an alpha-mannosidase of sea-squirt.

An alpha-mannosidase was isolated from the extract of acetone powder of CHCl3-treated internal organs of the sea-squirt, Styela plicata. The enzyme was purified 4,110-fold in 11% yield. The preparation was fairly homogeneous on disc and SDS-polyacrylamide gel electrophoreses and Sephadex G-200 chromatography. The enzyme had an estimated molecular weight of 275,000 by gel chromatography and 70,000 by SDS-polyacrylamide gel electrophoresis, and was therefore considered to be a tetramer. The optimum pH for the enzyme activity was 3.4 but the stable pH range was from 4 to 6. The isoelectric point was 5.0. The enzyme was activated by Zn2+ but inhibited by Cu2+, Fe2+, Hg2+, and EDTA. The isolated enzyme released mannose not only from stem bromelin glycopeptide and ovalbumin glycopeptide but also from yeast mannan.

Animals↗
PubMed1983

Physical theory of some interface phenomena in hemorheology.

The following four subjects are discussed theoretically from a physical standpoint: (1) the effect of the wall of a capillary viscometer on the apparent viscosity of blood; (2) the effect of electric charge on capillary flow; (3) the electric aspect of platelet adhesion and aggregation; and (4) multiphase polymeric materials as antithrombogenic materials. Copley and Scott Blair found a remarkable decrease in the apparent viscosities of blood, plasma, and serum in a fibrin-coated glass tube as compared with those in a glass tube without fibrin-coating. It is shown that the phenomenon cannot be explained by the existence of an electric double layer unless the zeta potential is positive. It is suggested that a reduction of the apparent viscosity of blood may be explained by a slight increase in the thickness of a plasma layer. It is shown that the existence of a slight gap between red cells and the capillary wall due to an electrostatic repulsion will remarkably lower the capillary flow resistance. An electric aspect of endothelial injury is discussed in relation to the adhesion of platelets to the injured endothelium. Platelet aggregation is discussed in accordance with the theory of Verwey and Overbeek , and a possible mechanism of thrombus formation due to a turbulent motion of blood is suggested. The significance of a multiphase polymeric material for an antithrombogenic surface is emphasized. It is suggested that sufficiently large conformational change of macromolecules will be favorable to antithrombogenicity of a polymeric material.

Blood Coagulation↗
PubMed1983

A note on a theoretical study of erythrocyte sedimentation.

An entire settling curve for whole blood is derived theoretically based upon Chien's expression for the viscosity of whole blood at hematocrits in excess of 40%. This problem was already studied by Puccini et al. in 1977. The aim of this note lies in correcting a mistake found in their treatment of a differential equation. The functional form of the entire settling curve differs, of course, from that obtained by them. It is shown that the settling curve is governed by only two parameters. The comparison of our theoretical formula with experimental data is left for our future task. It is suggested that the meniscus will be curved in close neighborhood of the glass wall due to the fluid mechanical influence of the wall. The effect of the aggregation of red cells will also be taken into account in future.

Animals↗
PubMed1983

[Experimental and clinical evaluation of a new cephamycin antibiotic, cefotetan, in pediatrics].

A series of studies was performed on the use of cefotetan (CTT) in the field of pediatrics. The results that were obtained are described below. The minimum inhibitory concentrations (MICs) of CTT against strains of E. coli and K. oxytoca that were recently isolated from child patients were found to mostly be 0.78 micrograms/ml or less. Even strains that were highly resistant to the action of ABPC were sensitive to CTT. CTT was administered to pediatric patients by intravenous drip infusion or by one shot intravenous injection, and then the concentration of the drug in the serum was monitored. The same procedures and dosages were employed for CFX and CMZ. In comparison with these 2 antibiotics, CTT showed a higher peak concentration in the serum, and it was retained in the blood for a longer time. The half-life of the CTT serum concentration was 2 hours or more in most of the subjects. When CTT was administered in a dosage of 10 mg/kg by intravenous drip infusion, the drug could still be detected in the serum as long as 12 hours later in some cases. Repeated intravenous drip infusion administration of CTT was not found to result in any accumulation of this antibiotic in the serum. During the 8-hour period following intravenous injection of CTT, about 50 to 80% of the administered dose was found to be excreted in the urine in its active form. During the acute phase of meningitis, intravenously injected (one shot) CTT was found to be transferred to the cerebrospinal fluid in a concentration that was sufficient to kill those bacteria that were sensitive to the action of this antibiotic. It was proven that, following the intravenous injection of CTT, the concentration of this drug in the feces was sufficient to inhibit the growth of Salmonella, Campylobacter, etc. CTT was administered by intravenous drip infusion as therapy to a total of 37 child patients diagnosed as having acute infections; these infections consisted mainly of upper and lower respiratory tract infections, urinary tract infections, intestinal tract infections and suppurative diseases. The dosage of CTT used in the treatment of these diseases ranged almost from 20 to 40 mg/kg/day, given as 2 doses per day (at intervals of 10-12 hours). The efficacy rate of this therapeutic regimen was 97%.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗
PubMed1983

[Evaluation of cefpiramide, a new cephem parenteral preparation developed in Japan, in pediatrics].

Fundamental and clinical studies of cefpiramide (CPM), a newly developed cephem antibiotic with a broad spectrum, were performed and the following results were obtained. The serum levels of CPM after the intravenous injection or the drip infusion of CPM at dose of 10.0 approximately 46.7 mg/kg reached the peak of 75.8 approximately 274.0 micrograms/ml at 30 approximately 60 minutes after infusion and were 3.9 approximately 55.1 micrograms/ml at 8 hours after the infusion. Half-life of CPM in the blood was between 2.4 and 7.0 hours. The excretion rates of CPM into urine up to 24 hours after the infusion were 5.7 approximately 20.4%. Twenty-five patients with acute respiratory tract infection (RTI, 15 cases), urinary tract infection (UTI, 8 cases), cellulitis (1 case) and salmonellosis (1 case) were treated with CPM. The treatment by intravenous injection or drip infusion of 22 approximately 55 mg/kg/day (40 approximately 50 mg/kg/day) for mean 6 days resulted in 100% of good response in 15 cases of RTI and in 88% of good response in 8 cases of UTI. S. aureus, H. influenzae, E. coli, Proteus, Klebsiella and Salmonella group B were isolated from the culture of sputum or urine in the patients, and they were all eradicated by the treatment with CPM. No side effects were observed except eosinophilia in 1 case and the elevation of GOT and GPT in 1 case.

Adolescent↗
PubMed1982

Malignant hyperpyrexia and Duchenne muscular dystrophy: A case report.

We report a patient with Duchenne muscular dystrophy who developed malignant hyperpyrexia during general anaesthesia. During anaesthesia bradycardia was followed by ventricular fibrillation, on which ventricular flutter supervened and a body temperature rise of 0.6 degrees C for 15 minutes, myoglobinuria and elevation of CPK level were observed. The caffeine sensitivity test of biopsied muscle fibers revealed an increase in sensitivity, although there was no sign of muscle rigidity during or after anaesthesia. Diagnosis of Duchenne muscular dystrophy was first established after the development of malignant hyperpyrexia in the present case as well as in previously reported cases. Determination of serum CPK is very important before general anaesthesia.

Adenosine Triphosphatases↗
PubMed1982

The properties of two sea-squirt antigens.

The accuracy of radioimmunoassay (RIA) has been much improved for sea-squirt antigen Gi-x, which is considered to be of higher molecular weight than antigen Ei-M, by using radiolabeled Gi-x as a tracer. Gel chromatography monitored by the improved RIA revealed a wide distribution of molecular weight of Gi-x type antigens, in contrast to Ei-M. However, since a considerable portion of the anti-genic activity gave a single peak in gel chromatography with Sepharose 6B, the substance in the peak fractions was isolated as a fairly homogeneous preparation and referred to as Gi-rep. Gi-rep showed distinct characteristics of Gi-x type antigens and was clearly discriminated from Ei-M by radioimmunometry in vitro. The in vitro observation also suggested that Gi-rep and Ei-M carried a common antigenic determinant (type alpha), but that Ei-M also carried a specific determinant (type beta). The weight-average molecular weights were 1.1 x 10(5) for Gi-rep and 2.3 x 10(4) for Ei-M. Both preparations consisted of acidic glycoproteins with considerable amounts of sulfate and phosphate.

Animals↗
PubMed1982

Immunogenic properties of two types of sea-squirt antigens.

Two antisera were prepared in rabbits against substantially purified preparations of sea-squirt antigens, Gi-rep and Ei-M, which were apparently discriminated from each other in antigenic behavior in radioimmunoassay experiments. Radioimmunometric analysis of the interaction between the two anti-sea-squirt sera and the two antigens revealed that Gi-rep induced in rabbit only one type of antibody (type A) which reacted with Gi-rep and Ei-M in common, while Ei-M induced not only type A antibody having the common reactivity but also another antibody (type B) which was strictly specific to Ei-M. This observation supported the preceding suggestion that Gi-rep and Ei-M carried a common antigenic determinant (type alpha) but that Ei-M had an additional determinant (type beta) specific to Ei-M. In this connection, in view of the similarity of type A antibody in specificity to the blocking antibody induced in asthmatic patients with sea-squirt allergy on hyposensitization therapy with these antigen preparations, it was suggested that the presumed allergenic substance in sea-squirt also carries the type alpha determinant.

Animals↗
PubMed1982

Purification and characterization of a beta-N-acetylhexosaminidase of sea-squirt.

A beta-N-acetylhexosaminidase [EC 3.2.1.30] was isolated from internal organs of the sea-squirt, Styela plicata. The enzyme was purified 1,560-fold in 5% yield. The preparation was fairly homogeneous as examined by disc and SDS polyacrylamide gel electrophoresis and Sephadex G-200 chromatography. The molecular weight of the enzyme was estimated to be 132,000 by gel chromatography and 66,000 by SDS polyacrylamide gel electrophoresis. Therefore, this beta-N-acetylhexosaminidase was considered to be a dimer. The optimum pH for activity was 4.0 but the enzyme was stable in the pH range from 5 to 6. The isoelectric point was 4.99. This enzyme was inhibited by Fe2+, Hg2+, Ag+, and PCMB but not by acetate. The isolated enzyme hydrolyzed both p-nitrophenyl-N-acetyl-beta-D-glucosaminide and p-nitrophenyl-N-acetyl-beta-D-galactosaminide. The hydrolysis rate of p-nitrophenyl-N-acetyl-beta-D-galactosaminide was 43% of that of p-nitrophenyl-N-acetyl-beta-D-glucosaminide. The enzyme liberated N-acetylhexosamine from asialodegalactosyl ovomucoid glycopeptide, asialodegalactosyl fetuin glycopeptide and the fragment of hyaluronic acid prepared by hyaluronidase treatment.

Acetylglucosaminidase↗
PubMed1982

[Fundamental and clinical studies in pediatric field on ceftizoxime (author's transl)].

Fundamental and clinical studies in the pediatric field on ceftizoxime were carried out, and the following results were obtained. 1. In 4 children age from 3 years to 5 years, the serum concentrations and urinary excretion of ceftizoxime in a dose of 20 mg/kg by intravenous drip infusion over 60 minutes were measured. The peak serum levels were 22.0--84.0 microgram/ml (mean 45.0 microgram/ml) at the end of infusion. The mean serum levels after the end of infusion were 16.9 microgram/ml at 30 minutes, 12.1 microgram/ml at 1 hour, 6.2 microgram/ml at 2 hours, 1.6 microgram/ml at 4 hours and 0.6 microgram/ml at 6 hours, with mean serum half-life (T 1/2) of 1.03 hours, mean urinary recovery rate was 64.9% up to 6 hours. 2. Concentrations of the drug in the cerebrospinal fluid in 1 patient with purulent meningitis at 30 minutes after an intravenous drip infusion of about 33.3 mg/kg were 0.2 to 1.5 microgram/ml, which were 8 to 60 times higher than the MICs of the causative organisms. 3. Ceftizoxime was administered to 38 children with pneumonia, bronchitis, Salmonella enteritis, purulent meningitis, etc. in the daily dose of 44--200 mg/kg for 3--19 days. Clinical response was excellent in 24, good in 12, poor in 1 and unknown in 1. The drug was proved to be very effective in 1 case of purulent meningitis due to H. influenzae. As for side effect, eruption was observed in only 1 case.

Adolescent↗