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Biomedical subjects

H Hatano

Publications and source records attributed to H Hatano.

At least 127 records · Page 7Linked to original sources
PubMed1977

Capability of complement fixation of pemphigus antibodies in vitro.

The capability of complement fixation of pemphigus antibodies was tested using combined in vitro complement immunofluorescent (IF) staining methods. Three sera out of 25 serum samples from 22 pemphigus patients revealed positive reactions, while all other sera gave negative results. Specificity control tests confirmed the positive reactions to be specific for complement staining. Complement fixing pemphigus antibodies were titrated lower than corresponding IgG antibodies and were demonstrable only in the extensive stage of the disease. Thus, the present work supplied evidence that pemphigus antibodies fix complement in vitro. However, the discrepancy still remains between the in vivo deposition of complement in most cases of pemphigus and in vitro capability of complement fixation in only few cases. More investigations should be needed to explain the exact role of complement in pemphigus acantholysis.

Antibodies↗
PubMed1977

Electron spin resonance studies on the lipoxygenase reaction by spin trapping and spin labelling methods.

The rate of oxygenation and that of trapping linoleic acid free radicals in the lipoxygenase [EC 1.13.11.12] reaction were measured in the presence of linoleic acid, oxygen, and nitrosobenzene at various concentrations, with a Clark oxygen electrode and ESR spectroscopy. The results were interpreted under the assumption that the free radical of linoleic acid, an intermediate of the lipoxygenase reaction, reacts competitively with oxygen or nitrosobenzene. The oxidation of the iron in the active site of lipoxygenase caused by the spin label reagent, 2-(10-carboxydecyl)-2-hexyl-4,4-dimethyl-3-oxazolidinyloxyl, was also observed by ESR- and fluorescence-spectroscopy.

Electron Spin Resonance Spectroscopy↗
PubMed1977

[Use of clindamycin-2-phosphate in ophthalmology (author's transl)].

Clindamycin-2-phosphate was studied to evaluate its possible use in ophthalmology. 1. Sensitivity of organisms isolated from human clinical materials: Of 44 staphylococcal strains in vitro studied 13 were highly sensitive to 0.1 mug/ml and 28 were resistant to 100 mug/ml or more of clindamycin-2-phosphate. 2. In experiments with rabbits, clindamycin-2-phosphate showed superior penetration into the ocular tissues after intravenous injection than after intramuscular injection. 3. Clindamycin-2-phosphate was administered intramuscularly at the dose of 300 mg to 6 healthy volunteers. The blood concentrations of 6 cases averaged 3.2 mug/ml after 1 hour, and 0.8 mug/ml after 6 hours. 4. Fourteen patients with extraocular infection were treated with daily intramuscular administration of 300 mg of clindamycin-2-phosphate. All of them improved by the treatment, and no side effect was observed.

Adult↗
PubMed1976

Studies of short-lived radicals in the gamma-irradiated aqueous solution of uridine-5'-monophosphate by the spin-trapping method and the liquid chromatography.

An aerated aqueous solution of uridine-5'-monophosphate was gamma-irradiated with 2-methyl-2-nitrosopropane as a spin-trapping reagent. Liquid chromatography was applied to separate the stable nitroxide radicals in the irradiated solution. The radicals were detected by U.V. and e.s.r. spectrometry. The e.s.r. detection showed four peaks in the chromatogram. The orcinol method for detection of the residual sugar moieties was applied before and after reduction of the base to determine the existence of the 5,6-double bond for the molecules in each fraction. From the combined results of the e.s.r. and orcinol methods, the short-lived radicals which were trapped by 2-methyl-2-nitrosopropane were identified as radicals of N-1 and C-6 positions of the base moiety and t-butyl radical which was the radiolytic product of the trapping reagent.

Chromatography, Liquid↗
PubMed1976

Electron paramagnetic resonance studies on spin-labelling of pepsin: effects of temperature, pH and urea on its conformation.

Pepsin was spin-labelled with N-(1-oxyl-2,2,6,6-tetramethyl-4-piperidyl) bromoacetamide, possibly at the active site, at a beta-catboxyl group of a reactive aspartic acid. The spectrum of the spin-labelled pepsin showed that the spin probe was strongly immobilized (correlation time is greater than or equal to 10(-8) sec). Spin-labelled pepsin was thermally denatured at various temperatures and electron paramagnetic resonance (e.p.r.) spectra were taken at various times. Rates of denaturation estimated from the e.p.r. spectra at various temperatures showed that the enthalpy and entropy of thermal denaturation of spin-labelled pepsin at pH 3.5 were 48.0+/-4.9 kcal/mole and 214.7+/-14.5 e.u. respectively. Addition of conc. NaOH or 1 M acetate buffer at pH 6.0 sharpened e.p.r. spectra of the spin-labelled pepsin, indicating that the spin probe became mobilized by alkaline denaturation. Addition of urea caused unfolding of the protein which increased with the urea concentration, although only slight transition of conformational changes was observed in the e.p.r. spectra.

Electron Spin Resonance Spectroscopy↗
PubMed1976

Atigenic similarity between Ceratocystis species and Sporothrix schenckii as observed by immunofluorescence.

Antigenic properties of Sporothrix schenckiii and 2 species of Ceratocystis (C. stenoceras and C. ulmi) were compared by indirect immunofluorescent staining technique. Both species of Ceratocystis and 2 strains of S. schenckii reacted equally well with the unabsorbed antisera against 2 strains of S. schenckii, indicating that these three species share common antigen. The absorption experiments showed that only S. schencki human strain demonstrated a unique antigen. These results support the hypothesis of Ceratocystis-Sporothrix complex in the point that both species have one major common antigen.

Antigens, Fungal↗
PubMed1975

Peptide hydrogen exchange rates in Streptomyces subtilisin inhibitor.

The exchange reaction of the peptide NH protons of a microbial protease inhibitor (Streptomyces subtilisin inhibitor) with deuterium atoms in 2H2O (p2H 6.8) has been studied by proton magnetic resonance in the temperature range 56-71 degrees C. Both slowly and rapidly exchanging processes have been observed. The number of slowly exchanging protons is estimated to be 25 +/- 2 per subunit of the protein molecule. The decay of the slowly exchanging proton signals follows a single time-exponential function at each temperature. The observed first-order rate constants have been analyzed to give the denaturated fraction of the protein as a function of temperature with a consequent enthalpy (56 kcal/mol) and an entropy (137 cal/degree per mol) of denaturation. The results indicate the high conformational stability of this protein against heat denaturation.

Bacterial Proteins↗
PubMed1975

Modification of isoleucine-16 acetylated delta-chymotrypsin.

Activation of acetylated chymotrypsinogen with trypsin leads to catalytically active acetylated delta-chymotrypsin containing NH2-terminal isoleucine. The importance of the cationic terminus to the control of the active conformation of acetylated delta-chymotrypsin has been demonstrated (Oppenheimer, H. L., Labouesse, B., and Hess, G. P. (1966) J. Biol. Chem. 241, 2720). Later studies appeared to suggest that the modification of isoleucine-16 of delta-chymotrypsin is not accompanied by the loss of catalytic activity as measured by the hydrolysis of N-acetyl-L-tyrosine ethyl ester (Agarwal, S. P., Martin, C. J., Blair, T. T., and Marini, M.A. (1971)Biochem. Biophys. Res. Commun. 43, 510; Blair, T. T., Marini, M. A., Agarwal, S. P., and Martin, C. J. (1971) FEBS Lett. 1486) or by the loss of active site content (Ghelis, C., Garel, J. R., and Labouesse, J. (1970) Biochemistry 9, 3902). In the present studies, controlled acetylation of the terminal alpha-aminogroup of acetylated delta-chymotrypsin with acetic anhydride led to a progressive loss of active sites of the enzyme. Determination of the catalytic and kinetic properties of the modified enzyme with the specific ester substrate N-acetyl-L-tyrosine ethyl ester or the nonspecific substrates p-nitrophenyl acetate and cinnamyol imidazole gave nearly identical results. With N-acetyl-L-tyrosine ethyl ester as substrate, the Km (app) values for acetylated delta-chymotrypsin (1.0 plus or minus 0.1 mM) and the modified enzyme (0.67 plus or minus 0.05 mM) are nearly identical and the kcat value is reduced to about 25% in the latter enzyme species. This value correlates well with about 20% of the active sites in this enzyme as measured by the rapid initial liberation of p-nitrophenol. With p-nitrophenyl acetate as substrate, the acylation rate constants (0.13 plus or minus 0.04 s(-1) at pH 6.0, 25 degrees, in 3.3% acetonitrile) and the deacylation rate constants (0.01 s(-1) at pH 8.5, 25 degrees, in 3.3% acetonitrile) are identical for the acetyl isoleucine-16 and the isoleucine-16 enzymes. Furthermore, the residual enzyme activity could be correlated well with the residual NH2-terminal isoleucine content and with the moles of [1--14C]acetyl groups incorporated per mol of the enzyme. The activity associated with the modified enzyme can be attributed to the enzyme species in which isoleucine-16 of acetylated delta-chymotrypsin is not acetylated. These data are in general agreement with the studies of Ghelis et al. (1970) but are in disagreement with the results of Blair et al. (1971) and of Agarwal et al. (1971) and confirm the hypothesis that the final conformation of acetylated delta-chymotrypsin containing an acetylated NH2 terminus is catalytically inactive and resembles acetylated zymogen in many of its physical properties.

Acetates↗