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Biomedical subjects

M Muratsugu

Publications and source records attributed to M Muratsugu.

17 recordsLinked to original sources
PubMed1992

Detection of antistreptolysin O antibody: application of an initial rate method of latex piezoelectric immunoassay.

Latex plezoelectric immunoassay (LPEIA) is a new latex immunoassay using a plezoelectric quartz crystal (Kurosawa et al. Chem. Pharm. Bull. 1990, 38, 1117). This assay requires no immobilization of antigen or antibody on an electrode surface of a plezoelectric crystal, while the immobilization is indispensable for ordinary immunoassays using a plezoelectric crystal as a microbalance. The present paper improves a previous method (end-point analysis) by introducing the initial rate method using a batch cell; reduction of assay volume (1.2 mL) and shortening of assay time (2-3 min) were achieved. This assay was applied to the detection of antistreptolysin O antibody (ASO) in serum. The frequency change was proportional to the ASO concentration up to 1040 IU mL-1, and the method has good sensitivity for actual clinical application. The volume of serum required for the assay was 0.02 mL. Twenty-four clinical specimens were analyzed with this LPEIA, and the values obtained were compared with those obtained with a turbidimetric latex agglutination method. The correlation coefficient between these values was 0.950 (P < 0.01).

Agglutination↗
PubMed1992

Plasma-polymerized allylamine film used as a new solid phase in immunoradiometric assay (IRMA): effect of antibody (F(ab')2 fragment) concentration on dose response in two-site IRMA.

Allylamine (ALAM) film was plasma-polymerized on a flat glass (referred to as ALAM(GLA): GLA refers to a flat glass plate) for use as a solid phase in two-site immunoradiometric assay (two-site IRMA). Adsorption of F(ab')2 anti-human immunoglobulin G [formula: see text] to ALAM(GLA) was larger than adsorption on a polyvinyl chloride plate (referred to as PVC). Contrary to the expectation that the dose response for human IgG (hIgG) on ALAM (GLA) was better than that on PVC, the dose responses on both solid phases were the same. This phenomenon was independent of molecular size of the antigen (Ag) (hIgG or Fc fragment of hIg G (hIgG-Fc)) and also the reaction with protein A (pA). Because direct measurements of binding with 125I-labeled hIgG (hIgG*) or hIgG-Fc (hIgG-Fc*) showed no difference between ALAM(GLA) and PVC, the phenomenon was not due to the second step in the system of two-site IRMA (an Ag--Ab reaction (Ab refers to antibody)). These results indicated that the phenomenon was due to the first step (the adsorption of [formula: see text] to a solid phase). When the concentration of [formula: see text] immobilized on the solid phases was lowered, a significant increase in the dose response was observed for ALAM(GLA).

Adsorption↗
PubMed1991

Electrophoretic mobility of cefodizime-treated Staphylococcus aureus and chemiluminescence of human polymorphonuclear leucocytes.

The electrophoretic mobility of Staphylococcus aureus 209P treated with cefodizime or cefotiam was examined by microscopic electrophoresis, and the production of oxygen-derived radicals by human polymorphonuclear leucocytes (PMN) was measured by a luminol-chemiluminescence assay. S. aureus cells moved from the negative to the positive electrode. Treatment with more than 0.039 mg/L (1/256 MIC) cefodizime or 0.313 mg/L (1/4 MIC) cefotiam significantly reduced the mean mobility compared with the untreated bacterial cells. The decrease of the electrophoretic mobility of antibiotic treated bacteria indicated the decrease of the negative charge of the cell surface. Chemiluminescence of PMN when stimulated by S. aureus treated with more than 0.156 mg/L cefodizime (1/64 MIC) or 1.25 mg/L cefotiam (MIC) increased significantly compared with the untreated cells. These results suggested that the antibiotics caused a decrease of negative charge density on the cell surface of S. aureus, followed by an increase of phagocytic activity of PMN for S. aureus. Furthermore, cefodizime showed this effect even at the low drug-concentration which did not influence the growth of the bacteria cells.

Cefotaxime↗
PubMed1988

Effects of lead on sialic acid content and survival of rat erythrocytes.

The anemia frequently observed in lead poisoning is thought to result from a shortening of erythrocyte survival in combination with inhibition of hemoglobin synthesis. However, the exact mechanism by which lead shortens erythrocyte survival remains unclear. In the present study, the effects of lead, injected intraperitoneally, on sialic acid content and survival of rat erythrocytes were investigated in order to study the relationship between them. As indices of lead exposure, hemoglobin (Hb) levels, hematocrits (Ht) and blood lead (blood Pb) levels in the injected rats were also examined. Exposure to lead significantly decreased the sialic acid content of the erythrocyte membrane. The decreases in sialic acid content were evident to some extent below a blood Pb level of 100 micrograms/100 ml and generally present at a level of 100 micrograms/100 ml and higher. In the rats exposed to lead a significant negative correlation was found between sialic acid content and the logarithm of blood Pb level. A shortening of erythrocyte survival was also observed in the rats exposed to lead.

Animals↗
PubMed1988

A 3,3',5-triiodothyronine autoantibody (IgG, lambda) in a case of Hashimoto's thyroiditis.

A 19-year-old Japanese woman with Hashimoto's thyroiditis appeared to be hypothyroid by clinical and laboratory criteria. However, the serum levels of total T3 and free T3 as measured by solid-phase radioimmunoassay were not compatible with the clinical features and other laboratory data, therefore the presence of serum T3 autoantibodies was suspected. Gel filtration analysis (Sephacryl S-300) of acid-treated serum trace-labeled with 125I-T3 revealed binding to high and intermediate molecular fractions, indicating that the T3 binding autoantibody may have been IgM and IgG. The antibody, however, was identified as IgG class and lambda type by immunoprecipitation and immunoelectrophoresis/autoradiography. The T3 binding autoantibody did not show antigenic cross-reactivity with T4 as far as we know from experiments. The affinity and the binding capacity of the antibody for T3 were estimated 6.4 X 10(6) l/mol and 9.1 X 10(-9) mol/l, respectively.

Adult↗
PubMed1986

Effect of lead on electrophoretic mobility of rat erythrocytes.

Lead often affects the erythrocyte membrane. The relationship between the changes in erythrocyte membrane and the anemia caused by lead is still unclear. Initially, the effect of lead injected intraperitoneally on the electrophoretic mobility of rat erythrocytes was investigated in order to study the relationship between them. As indices of lead exposure, hemoglobin (Hb) levels, hematocrits (Ht), delta-aminolevulinic acid dehydratase (ALA-D) activities and blood lead (blood Pb) levels in the injected rats were also examined. Exposure to lead significantly decreased the mobility of rat erythrocytes. The changes in mobility seemed to be less sensitive than those in ALA-D activity, however, the decreases in mobility were simultaneous with or prior to those in Hb level and Ht. The decreases in mobility were evident to some extent below a blood Pb level of 100 micrograms/100 ml and generally present at a level of 100 micrograms/100 ml and over. In the rats exposed to lead a significant negative correlation was found between the mobilities and the logarithms of blood Pb level.

Animals↗
PubMed1982

Evaluation of fluorescence polarization immunoassay for serum thyroxine determination.

We have evaluated a fluorescence polarization immunoassay for thyroxine (T4) using the polarization analyzer IBF-129. Fluorescence polarization could be measured within 20 to 23 seconds after addition of fluorescein labeled thyroxine. The method exhibited excellent specificity and acceptable accuracy. The average intra- and inter-assay coefficients of variation were 4.8 and 12.3%, resepectively. The fluorescence polarization immunoassay was compared with a radioimmunoassay (RIA) using 96 clinical serum samples and gave a linear regression equation: y = 0.92 x + 12.5, with a correlation coefficient of r = 0.866 (P less than 0.001).

Fluorescence Polarization↗
PubMed1979

Membrane potential of mitochondria measured with an electrode sensitive to tetraphenyl phosphonium and relationship between proton electrochemical potential and phosphorylation potential in steady state.

The membrane potential of mitochondria was estimated from the accumulation of tetraphenyl phosphonium (TPP+), which was determined with the TPP+-selective electrode developed in the present study. The preparation and some operational parameters of the electrode were described. The kinetics for uptake by mitochondria of TPP+ and DDA+ (dibenzyldimethyl ammonium) were analyzed, and it was found that TPP+ permeated the mitochondrial membrane about 15 times faster than DDA+. The final amounts of accumulation of TPP+ and DDA+ by mitochondria were approximately equal. For the state-4 mitochondria, the membrane potential was about 180 mV (interior negative). Simultaneous measurements of TPP+-uptake and oxygen consumption showed that the transition between states 3 and 4 was detectable by use of the TPP+-electrode. After the TPP+-electrode showed that state-4 was reached, the extra-mitochondrial phosphorylation potential was measured. The difference in pH across the membrane was measured from the distribution of permeant anion, acetate, so as to calculate the proton electrochemical potential. The ratio of extra-mitochondrial phosphorylation potential to proton electro-chemical potential, n was close to 3. This value of n was also found to be 3 when ATP was hydrolyzed under the condition that the respiratory chain was arrested. The implication that n = 3 was discussed.

Adenosine Diphosphate↗
PubMed1977

Selective electrode for dibenzyl dimethyl ammonium cation as indicator of the membrane potential in biological systems.

The electrode sensitive to dibenzyl dimethyl ammonium (DDA+), which is considered to be an indicator of the membrane potential, was constructed by using tetraphenyl borone (TPB-) embedded in dichloroethane. Rapid and Nernstian responses were exhibited against DDA+ solutions ranging between 10(-2) and 3 - 10(-6) M in concentration. High selectivity for DDA+ was observed in the presence of various inorganis salts, ADP, ATP, oxidizable substrates and sugars. The electrode developed here was used to measure the DDA+ uptake in Streptococcus faecalis and the results agreed with those reported by Harold, F.M. and Papineau, D. ((1972) J. Membrane Biol. 8, 27-44 and 45-62). While they determined the DDA+ concentration in the medium by measuring the absorbance of the filtrate treated with the ion-exchangers, the electrode can measure directly the DDA+ concentration in the bacterial suspension without any any pretreatment. It was also shown that the electrode can measure the DDA+ uptake in mitochondria during energization.

Animals↗