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Biomedical subjects

T Okabe

Publications and source records attributed to T Okabe.

At least 523 records · Page 29Linked to original sources
PubMed1978

Antigenic properties of a cell line from human prostate carcinoma (EB 33).

Evidence for tumor-specific transplantation antigens of human prostate carcinoma was gained by others from in vivo sensitization. The fact that these antigens have not been detected by in vitro methods prompted us to investigate whether EB 33 cells, originated from a human prostate carcinoma by one of us (F.H.S.), expressed these antigens. Using 3-M potassium chloride extracts of EB 33 cells for immunization of New Zealand white rabbits, we obtained xenogeneic antibodies. Further analysis of their specificity was achieved by indirect immunofluorescence and by measurement of their cytotoxicity in a [51Cr]-release test. Xenogeneic antibodies were cytotoxic for EB 33 cells. However, the extent of cell lysis depended on the passage number of EB 33 target cells, thus reflecting an alteration of the antigenicity of the EB 33 cell population during culture. Formation of nonspecific antibodies could be absorbed with HeLa cells. As HLA were not detectable on EB 33 cells, results obtained from absorption experiments with homogenates of normal and malignant prostate tissue may argue for organ-specific and tumor-related transplantation antigens on EB 33 cells.

Antibodies, Neoplasm↗
PubMed1977

3-Halo-5,7-dimethylpyrazolo [1,5-a]pyrimidines, a nonbenzodiazepinoid class of antianxiety agents devoid of potentiation of central nervous system depressant effects of ethanol or barbiturates.

Forty derivatives (1-40) of pyrazolo[1,5-a]pyrimidine were synthesized and evaluated for antianxiety properties via gross behavioral observations in rats. Five of these compounds, including 5,7-dimethylpyrazolo[1,5-a]pyrimidine (6) and the 3-fluoro (7), 3-chloro (8), 3-bromo (9), and 3-iodo (10) derivatives, were selected for advanced evaluation. Although 6 and 7 had marginal activity, 8-10 had an anxiolytic effect in animals comparable to the clinically useful benzodiazepines, diazepam, and chlorodiazepoxide. Comparison with chlorpromazine indicated that 6-10 are probably not antipsychotic agents. These compounds also lacked activity in anticonvulsant and analgesic tests. Acute toxicity data (mouse, ip and po) indicated that 8-10 had excellent therapeutic ratios, although 10 was more poorly absorbed than 8 and 9. Further demonstration of anxiolytic efficacy was obtained by comparing the effects of 8 and 9 with the benzodiazepines in modifying provoked aggression in monkeys, rats (muricide), and fighting mice. The most remarkable observation, however, was that 8 and 9 had no effect, at the anxiolytic threshold, in potentiating the CNS depressant effects of ethanol or sodium barbital (po) in treated mice. In contrast, diazepam and chlorodiazepoxide potentiated this drug interaction effect at minimal anxiolytic doses.

Aggression↗
PubMed1977

Analysis of Asgar-Mahler reaction zone in Dispersalloy amalgam by electron diffraction.

Selected area reflection electron diffraction has been used to determine the phases present in the reaction zones surrounding the Ag-Cu eutectic dispersant in Dispersalloy amalgam. The experiments were carried out on two kinds of specimens, (1) Dispersalloy amalgam and (2) Dispersalloy amalgam using 30, 50, 75, and 100% more mercury than found in commercially available capsules. The results show that the reaction zones in the specimens of the present investigation consist of Cu6Sn5 and Ag2Hg3. These diffraction data confirm the presence of the phases in the reaction zone which are suggested by the elemental analysis obtained by Mahler and his associates using an electron probe. Moreover, the strong intensity of the eta-Cu6Sn5 diffraction rings suggests a composition which is predominantly Cu6Sn5, again, in agreement with the electron probe data.

Chemical Phenomena↗
PubMed1977

Diffusion of mercury in HgSn8 (gamma2 phase).

The tracer diffusion coefficients of mercury in a Sn-Hg alloy (Sn 82.6 and Hg 17.4 wt.%; HgSn8 (gamma2 phase)2.6 and Hg 17.4 wt.%; HgSn8 [gamma2 phase]) were measured by the residual activity method at temperatures ranging from 35.5 to 95 degrees C. The Arrhenius equation for the mercury tracer was found to be Dv=2.10 X 10(-3) exp (-8.96 X 10(3)/RT) cm2/sec. The diffusivity of mercury in the three phases, the gamma (Ag3Sn), gamma1 (Ag2Hg3) and gamma2 (HgSn8) phase, that coexist in silver-tin dental amalgam have now been determined. Mercury diffuses fastest in gamma2 phase and slowest in gamma phase.

Dental Amalgam↗
PubMed1977

Demonstration of granulopoietic factor(s) in the plasma of nude mice transplanted with a human lung cancer and in the tumor tissue.

A human lung cancer (OTUK-tumor) was transplanted serially to nude mice, which invariably developed a marked neutrophilia. In order to analyze this phenomenon, in vitro agar culture studies were carried out. A three- to fourfold increase of colony-forming units in culture was observed in the femurs of these nude mice. Moreover, the plasma of nude mice bearing this tumor, as well as the tumor extract, had a significantly higher colony-stimulating activity on mouse bone marrow cells than appropriate controls. This activity had the property to stimulate granulocyte and/or mixed cell type colonies rather than mononuclear cells. This activity was also demonstrated, in a dose-dependent way, on normal human bone marrow cells. These findings indicated that the OTUK-tumor produced human granulopoietic colony-stimulating activity, which may have stimulated granulopoiesis in vivo as well.

Animals↗
PubMed1977

Immunoglobulin M associated with secretory component and immunoglobulin A deficiency in bovine colostrum.

Immunoglobulin (Ig) M purified from bovine colostrum was examined by an immunodiffusion analysis with antisecretory IgA serum and was found to be associated with a secretory component. Some of the combined proteins were dissociated if treated with 5 M guanidine-HCl and others were not. Another immunodiffusion analysis of 23 specimens of colostrum led to the finding that certain colostrums were deficient in IgA, even though they contained IgG and IgM.

Animals↗
PubMed1976

Novel heterocyclic nitrofurfural hydrazones. In vivo antirypanosomal activity.

Hydrazine derivatives of several pyrazolo[1,5-alpha]pyrimidines (A), pyrazolo[1,5-alpha]-1,3,5-triazines (B), s-triazolo[1,5-alpha]pyrimidines (C), and imidazo[1,2-alpha]pyrimidines (D) were synthesized and condensed with 5-nitrofurfural in order to obtain the corresponding nitrofurfural hydrazones of each heterocycle (1d-14d). Each compound was screened for in vitro activity against Trypanosoma cruzi. The compounds were then tested in vivo against experimental infections of T. cruzi in laboratory (C3H/He strain) mice. An interesting structure-activity relationship was uncovered, revealing that 5-methyl-7-(5-nitrofurfurylidenehydrazino)pyrazolo[1,5-alpha]pyrimidine (2d) greatly increased the mean survival time (IMST) of mice with terminal infections. Subtle alterations in the structure of 2d, such as the substitution of a 5-hydrogen for the 5-methyl group (1d) or the substitution of the 3-hydrogen by the water-soluble 3-sulfonic acid (3d) or 3-sodium sulfonate (4d), resulted in a drastic loss of in vivo and in vitro activity.

Animals↗
PubMed1976

Synthesis and antimicrobial activity of some novel heterocycles. Azolo-as-triazines.

A general method for the preparation of substituted azolo-as-triazines is reported. The various alpha-aminoazoles (3-aminopyrazole, 3-amino-s-triazole, 5-amino-v-triazole, 2-aminoimidazole, 4(5)-aminoimidazole, and their substituted derivatives) were diazotized and coupled with active methylene reagents (beta-diketones, beta-keto esters, beta-keto acids, ethyl cyanoacetate and malononitrile) to afford intermediates which were then cyclized in methanol, acetic acid, or benzene. The cyclized products were the corresponding pyrazolo[2,3-c]- (2), s-triazolo[2,3-c]- (3), imidazo[3,4-c]- (4), v-triazolo[1,2-c]- (5), and imidazo[3,4-c]-as-triazines (6) with substituents such as amino, alkyl (or hydrogen), ester, ketone, or nitrile, depending on the methylene reagent used. Of the 28 compounds synthesized (representative of the five heterocycles) six, with various substituents, exhibited specific in vitro antimicrobial activity. Compounds 2b and 2d inhibited the gram-negative bacterium Pseudomonas, 3a, and 5a inhibited the gram-positive Staphylococcus, 2h inhibited the dermatophyte Trichophyton, and 2c inhibited the yeast Candida in the MIC (minimum inhibitory concentration) range of 0.40-0.16 mumol/ml.

Anti-Bacterial Agents↗
PubMed1976

Opsonic activity and O-agglutinins against Escherichia coli in bovine colostrum.

Anticolibacillus antibody activity was examined in 16 samples of bovine colostrum by O-agglutination test with 6 serotypes of Escherichia coli, and its correlation with the manifestation of diarrhea was analyzed for newborn calves fed these colostrums. The 4 colostrums fed to newborn calves having diarrhea within a few days after birth had significantly lower agglutinin titers for all the serotypes tested than did the other colostrums. Other newborn calves fed on the remaining 12 colostrums did not manifest clinical signs of enteric disorders. The agglutinin spectrum against the E coli serotypes was similar between colostrum samples from the same stockfarm, but variable among the farms from which the colostrum had been collected. The agglutinin activity was sensitive to 2-mercaptoethanol and was found mainly in the macroglobulin fraction of gel filtration, indicating that the activity was due to antibodies of the immunoglobulin M type. This was evidenced directly by the agglutination test of purified immunoglobulins. Opsonic activity of colostrum and immunoglobulins purified therefrom was estimated by the rate of decrease in the number of viable E coli injected into mouse peritoneal cavity. The results indicated that the opsonic activity in colostrum was also attributed mainly to immunoglobulin M antibodies, although the contribution of immunoglobulin A and G antibodies was not ruled out. A part of the opsonic activity in colostrum seemed due to heat-labile component(s) as well.

Agglutinins↗
PubMed1975

Auger analysis of surface films on Ag3Sn.

The surface properties of Ag3Sn are important in the amalgamation process so that mechanical abrasion is generally necessary to get a satisfactory amalgam. Therefore, the present study was undertaken to characterize the surface of Ag3Sn after several types of surfaces treatments. Homogeneous polycrystalline rods of Ag3Sn were prepared in vacuo from high purity (99.99%) Ag and Sn. Specimens were sliced from these rods and prepared as follows: (1) mechanically polished, (2) polished as in (1) and allowed to sit in air for three days and (3) polished as in (1) and electrolytically etched. Each of these specimens was examined by Auger electron spectroscopy. The results showed that after mechanical abrasion the surface film was primarily oxide and the Ag to Sn ratio was lower than the bulk composition, indicating preferential oxidation of Sn. After sitting in air sulfur was also present on the surface and the Ag to Sn ratio was greater than that immediately after polishing, indicating the formation of Ag2S. After electrolytic etching some oxide was still present, but only a trace of sulfide was found. However, the Ag to Sn ratio was greater than that for mechanically polished specimens, indicating preferential dissolution of Sn. Therefore, it is seen that the surface preparation of Ag3Sn has a marked effect on Ag and Sn concentrations and the nature of films at the surface.

Dental Alloys↗
PubMed1975

Amalgamation reaction on mercury-plated dental alloy (Ag3Sn).

The reaction between liquid mercury and Ag3Sn was studied at room temperature using a new type of specimen; i.e. bulk Ag3Sn electroplated with mercury. The surface morphology of the specimen and the phases formed on the Ag3Sn substrate were investigated by various techniques including optical microscopy, electron (scanning) microscopy, electron microprobe analysis, and electron diffraction. It was found that the mode of formation and type of crystalline phase appearing on the Ag3Sn specimen depended on the amount of mercury available. When the amount of mercury exceeded a certain quantity (about 1 mg/cm2) only the gamma1 and gamma2 phases were formed. On the other hand, when the amount of mercury was reduced below a certain low value (less than 0.3 mg/cm2), another silver-mercury phase, beta1, formed as tiny "liquid-like" drops. The experimental technique employed in the present investigation has proved to be an excellent method for studying the reaction between liquid mercury and metal specimens. This new procedure may be employed to evaluate the amalgamation ability of potential new alloy systems.

Chemical Precipitation↗
PubMed1975

Growth kinetics of gamma 2 crystals on mercury-plated Ag3Sn.

Previous work has shown that needles of gamma 2 crystals form when mercury is plated on the surface of an Ag3Sn specimen. In the present study, the growth kinetics of gamma 2 needles were investigated from room temperature to 50 degrees C for varying amounts of plated mercury. Straight-line relationships between crystal length and the square root of the time of growth showed that the growth rate is diffusion controlled. The growth rate increased with temperature up to 40 degrees C but decreased at higher temperatures. Further, as the temperature was increased, fewer gamma 2 crystals formed and their growth length decreased. This demonstrates that a number of competing factors are involved in the growth process at high temperatures.

Crystallization↗
PubMed1975

A new protein with a particular thermoprecipitability in bovine milk.

A new protein with a particular thermoprecipitability was isolated from bovine milk and tentatively termed milk pyroglobulin. The protein which was soluble at a relatively cold temperature was precipitated by raising the temperature to a certain degree depending on the concentration of the protein. The precipitate disappeared on recooling. This protein had the electrophoretic mobility of gamma globulin but did not carry either antigenic specificities of immunoglobulins or of free secretory component. The molecular weight was estimated to be approximately 60,000 in thin-layer gel filtration on Sephadex G-200 superfine gel, but the protein appeared to be convertible to molecules with a lower molecular weight of approximately 20,000 in the presence of bovine serum albumin. The presence of the albumin inhibited the thermoprecipitation as did alpha-lactalbumin but not IgG immunoglobulin from bovine colostrum. In SDS-polyacrylamide gel electrophoresis, the protein was separated into two components having a molecular weight of 19,000 and 10,000, respectively. Both components were thermoprecipitable and carried identical antigenic determinants.

Animals↗