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Biomedical subjects

H Maeda

Publications and source records attributed to H Maeda.

At least 1,405 records · Page 78Linked to original sources
PubMed1978

Assay of an antitumor protein, neocarzinostatin, and its antibody by fluorescence polarization.

I evaluated use of the fluorescence polarization technique to measure neocarzinostatin, a proteinaceous antitumor antibiotic, and its antibody, in serum. The antigen (neocarzinostatin), labeled with fluorescein isothiocyanate, was allowed to interact with its antibody in a cuvet, in the instrument, yielding an increase in the fluorescence polarization value. Antibody content was determined in the presence of a definite amount of the labeled antigen, fluorescence polarization values increasing in parallel with each addition of antibody. Antigen content was determined with a known amount of antibody, which reacted at first with an unknown amount of antigen in samples, followed by addition of a definite amount of the labeled antigen (competition). I used the method to determine a pharmacokinetic parameter, the apparent volume of distribution for neocarzinostatin in rabbits, using drug-injected rabbit sera. I evaluated precision, accuracy, and reproducibility, using various samples or possible interfering substances such as bilirubin and hemoglobin, and also compared results for antigen with those by single radial immunodiffusion assay. The present assay is fast (less than 2 min), sensitive (less than 10 nmol/liter can be detected), and simple (there is no separation step before readout of the results).

Animals↗
PubMed1978

Experimental and clinical studies on the formation of antibodies to neocarzinostatin, a new protein antibiotic.

The injection of clinical doses of neocarzinostatin (NCS) in guinea pigs did not result in antibody formation as judged by immunoelectrosyneresis, micro-Ouchterlony agar diffusion, fluorescence polarization, and passive cutaneous anaphylaxis reaction. This confirmed previous work on passive hemagglutination and passive cutaneous anaphylaxis reaction in a heterocytotropic system in guinea pigs. Forty-eight serum samples from 28 patients who were previously treated with NCS alone (8--161 mg) for a period of 8-85 days did not show any sign of antibody formation as revealed by immunoelectrosyneresis, micro-Ouchterlony agar diffusion, and fluorescence polarization techniques. In a homocytotropic system, the passive cutaneous anaphylaxis reaction was carried out with sera of sensitized guinea pigs and test guinea pigs which revealed that no IgE and IgA antibody to NCS was present in the sensitized sera. Those patients with bladder cancer who did not respond to NCS therapy or exhibit any side effects even after 21 mg were found to have proteolytic activity in their sera which degraded NCS very rapidly as revealed by the fluorescence polarization technique.

Anaphylaxis↗
PubMed1977

A simple colorimetric method for determination of serum triglycerides with lipoprotein lipase and glycerol dehydrogenase.

A simplified enzymic procedure to determine accurately serum triglycerides is described. Serum triglycerides are hydrolyzed completely to free fatty acids and glycerol by lipoprotein lipase from Pseudomonas fluorescens. The released glycerol is oxidized with glycerol dehydrogenase from Erwinia aroideae in the presence of NAD+, were the reduction of the enzyme-linked NAD+ is coupled to the reduction of nitro blue tetrazolium as a chromogenic indicator with phenazine methosulfate serving as an intermediate electron carrier of NADH. The absorbance at 570 nm is measured. The method requies only 20 microliter of serum and a 10-min incubation and is rapid and simple. The present method offers the measurement of a high concentration of triglyceride up to 1000 mg/dl serum. The results obtained by the present method show good correlation with those obtained by the glycerol kinase method (correlation coefficient, 0.989) or the acetylacetone method (correlation coefficient, 0.979). These results suggest that the proposed method will be utilized as a method or routine clinical test.

Colorimetry↗
PubMed1977

Kinetics of binding of oligosaccharides to a homogeneous pneumococcal antibody: dependence on antigen chain length suggests a labile intermediate complex.

Temperature-jump experiments were performed with di-, tetra-, and hexasaccharides derived from type III pneumococcal polysaccharide using a homogeneous corresponding antibody IgG 45-394. A decrease in stability of the oligosaccharide-antibody complexes with decreasing chain length was observed and entirely reflected in the decrease of the association rate constants which were 1.7 X 10(4) M-1 s-1 for the di-, 3.7 X 10(5) M-1 s-1 for the tetra-, and 1.1 X 10(6) M-1 s-1 for the hexasaccharide at 23 degrees C. The dissociation rate constants for all oligomers were about 12 s-1. This marked chain-length dependence of the association rate constants as well as their low values are unexpected for a single binding step. A mechanism is proposed which consists of a fast formation of a labile oligosaccharide-antibody precomplex followed by a slow isomerization step which is induced by the oligosaccharide ligands but which is chain-length independent.

Antibodies, Bacterial↗
PubMed1977

Preparation of N6-[N-(6-aminohexyl) carbamoyl]-adenine nucleotides and their application to coenzymically active immobilized ADP and ATP, and affinity adsorbents.

Reaction of ADP with hexamethylene diisocyanate in hexamethylphosphoramide followed by treatment in an acidic medium afforded three new adenine nucleotide analogues, N6-[N-(6-aminohexyl)carbamoyl]-ADP, N6-[N-(6-aminohexyl)carbamoyl]-ATP, and N6-[N-(6-aminohexyl)carbamoyl]-AMP in yields of 13%, 12% and 17%, respectively. The occurrence of the ATP analogue may be interpreted in terms of the equilibrium, 2ADP = ATP + AMP. Coenzymic activities of the ADP analogue against acetate kinase and pyruvate kinase were 82% and 20%, respectively, relative to ADP and those of the ATP analogue against hexokinase and glycerokinase were 63% and 87%, respectively, relative to ATP. These analogues were bound to CNBr-activated soluble dextran through their terminal amino group to give an immobilized ADP and an immobilized ATP, each of which was recycled in a system comprising acetate kinase and hexokinase, and when placed in a membrane reactor together with the enzymes, functioned as an immobilized coenzyme continuously yielding glucose 6-phosphate. A series of chemically defined affinity adsorbents were obtained by coupling these analogues to CNBr-activated Sepharose, and were used to separate the enzymes in a mixture of hexokinase, pyruvate kinase, phosphoglycerate kinase, lactate dehydrogenase, and alcohol dehydrogenase.

Adenine Nucleotides↗
PubMed1977

Fenestration of the middle cerebral artery.

Three cases of angiographically demonstrated fenestration of the middle cerebral artery are reported. The incidence of demonstration of fenestration of the middle cerebral artery by angiography is 0.26%. Its clinical significance is discussed briefly.

Adult↗
PubMed1977

Spontaneous deamidation of a protein antibiotic, neocarzinostatin, at weakly acidic pH. Conversion to a homologous inactive preneocarzinostatin due to change of asparagine 83 to aspartic acid 83 accompanied by conformational and biological alterations.

The amide content of neocarzinostatin (NCS), an antitumor protein, has been determined by analysing asparagine and glutamine in the Pronase-aminopeptidase M digests of tetra-S-carboxymethyl-NCS and carboxyl-modified NCS (modified with a water-soluble carbodiimide and [14C]glycine methyl ester). Preneocarzinostatin (PRE) was separated and purified from a crude NCS preparation by CM-cellulose column chromatography. PRE was found to contain one mole less asparagine than NCS, and asparagine was deamidated to aspartic acid in PRE. A time-dependent conversion of NCS to PRE at pH 3.2 at 4 degrees or in 0.1 M acetic acid at 26 degrees was studied in two ways; first, by quantitative determination of NCS and PRE by CM-cellulose column chromatography and second, by following the release of free NH3 during dialysis in an air-tight container. Within experimental error, PRE was indistinguishable from NCS in amino acid content after acid hydrolysis, as well as in apparent molecular weight as determined by SDS-disc gel electrophoresis (10% acrylamide), and N- and C-terminal amino acid residues. Both NCS and PRE shared a common antigenicity as determined by Ouchterlony's agar diffusion method. Only a slight difference between the two in electrophoresis on a cellulose acetate membrane and on a peptide map of the tryptic digest was demonstrated. PRE, however, was completely devoid of biological activity. In addition to the chromatographic difference, a conformational difference was observed by CD spectroscopy, namely, an apparently looser structure of PRE was indicated by the shallowness of the trough in the 240-265 nm region. This interpretation was supported by the finding that digestions by Pronase were more extensive with PRE than with NCS. These results indicate an important role of the single asparagine residue (Asn 83) of NCS in the biological activity, which is evidently governed by the conformation.

Amino Acids↗
PubMed1977

Mechanism of accumulation of the antitumor protein antibiotic neocarzinostatin in bladder tissue: intravenous administration, urinary excretion, and absorption into bladder tissue.

Some aspects of the absorption, distribution, and excretion of neocarzinostatin (NCS), a proteinous antitumor antibiotic, were studied in rabbits. NCS was given intravenously (i.v.) via the auricular vein, or [(14)C]NCS was instilled directly into the cavity of the bladder by tubing. In both groups, ureterostomy was performed, so that the drug excreted in the urine did not pass through the bladder. The results showed extremely rapid renal clearance; namely, two-thirds of the total recovered was excreted in the first 5 min. It was also shown that drug infused into the bladder cavity could be recovered in urine from the ureterostomized ureter. Also, the level of biological activity of NCS in bladder tissues after i.v. administration is significantly lower when ureterostomy is performed. Thus, evidence is presented for the absorption of NCS into bladder tissue from the lumen of the bladder. The high levels of NCS in bladder tissue are due to this effect as well as to accumulation via the iliac artery. These data should encourage further trials of NCS in bladder cancer. A study of urine containing NCS derived from i.v. administration showed an increase in antibacterial activity upon incubation, followed by a decrease. These effects are probably due to proteolysis, as shown by the appearance of a low-molecular-weight fragment and by the absence of such an increase in the presence of inhibitors of proteolysis.

Animals↗
PubMed1977

Mycobacterial antigens relating to experimental pulmonary cavity formation.

Lipid-protein mixtures were obtained from 2 strains of mycobacteria, and their cavity-forming activities were examined in rabbit lungs. The mixtures were separated into lipid and protein fractions by gel filtration on Sephadex LH-20 column. Neither lipid nor protein fraction alone had cavity-forming activity; however, restoration of the cavity-forming activity was observed by recombining the fractions. The activity was also reconstructed by combining the protein fraction with cell walls of bacille Calmette-Guérin. The protein fraction from Mycobacterium phlei was further separated into 2 fragments. The larger molecular fragment with a molecular weight of 10,000 daltons consisted of 60% protein and 40% carbohydrate and had cavity-forming activity in combination with the cell walls. The roles of lipid and protein of mycobacteria in cavity formation are discussed.

Animals↗