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Biomedical subjects

S Goto

Publications and source records attributed to S Goto.

At least 955 records · Page 53Linked to original sources
PubMed1985

Immune reactivity of allogeneically pregnant mice to paternal MHC antigens on fetal and placental cells assessed by second set rejection of ascites tumor cells.

In vivo immunogenicity of fetus- and placenta-derived cells as well as the immune reactivity of pregnant mice to fetal cells were examined for graft rejecting response (GRR). Systemic administration of small numbers of fetal cells but not placental cells from allogeneically pregnant mice (10(6) cells per mouse) or adult allogeneic spleen cells (10(4) cells) sensitized mice for second-set rejection of an ascitic tumor bearing paternal major histocompatibility complex (MHC) antigens. Despite this fact and the known positive humoral response, pregnant and parous mice are not even minimally sensitized with fetal MHC antigens for GRR transplacentally. Nevertheless, any pregnancy-related systemically active control, which would selectively prevent the mother from being sensitized for GRR by limiting numbers of semi-allogeneic fetal cells, was not demonstrable in either allogeneically or syngeneically pregnant mice. Irrespective of pregnancy, mice did not, however, respond to repeated administration of very small numbers of allogeneic spleen cells (5 X 10(2) cells per mouse) for graft rejection. These findings support the notion that deviation of maternal immunity to fetal antigens away from harmful GRR is mediated principally by local mechanisms which inhibit fetal cells from gaining access to the mother for GRR, and additionally by the innate inability of mice to respond to very small numbers of allogeneic cells that might escape past the local maternal-fetal barrier.

Animals↗
PubMed1985

Effects of rifampicin and phenobarbital on the fate of isoniazid and hydrazine in vivo in rats.

After the intraperitoneal (i.p.) administration of isoniazid (INH) to male Wistar rats, the liver and plasma levels of hydrazine (Hz) and acetylhydrazine (AcHz), which are hazardous metabolites of INH and well known as mutagens, carcinogens and hepatotoxins, were determined by gas chromatography-mass spectrometry (GC-MS). The levels of Hz in rifampicin (RMP)- or phenobarbital (PB)-pretreated groups were lower than those in the control group, while the amount of AcHz was scarcely altered. In each of the pretreated groups a pronounced increase in the oxidative elimination rate of Hz was observed. These results are of important toxicological significance in INH therapy with RMP, since an active intermediate of Hz seems to be a hepatotoxin.

Acetylation↗
PubMed1985

Accumulation of heat-labile elongation factor 2 in the liver of mice and rats.

Age-related changes of polypeptide chain elongation factor 2 (EF-2) in mouse and rat livers were investigated. The percentage of heat-labile components in EF-2 was 5 to 10% in young animals and 15 to 45% in old ones. These results and other findings (Takahashi et al., in press) support the idea that decrease in translational activity in old animals is due, in part, to alterations of protein components of the translational system.

Aging↗
PubMed1985

Histochemical acetylcholinesterase activity in the mucosa of the resected bowel in Hirschsprung's disease. An analysis of 30 cases.

Resected bowels from 30 patients with Hirschsprung's disease were consecutively investigated as to the length of the aganglionic segment and the extent of the increased mucosal acetylcholinesterase (AChE) activity. The latter was not always in accord with the length of aganglionic segment. The increased AChE activity not only did not reach the normal ganglionic segment proximally, but, in almost all cases also extended for less than 5 cm from the distal end of the resected bowels. In two cases with the ultra-short type of segment and in four with the short type of segment increased mucosal AChE activity extended for a short length only into the normal bowel segment. The more advanced the patient's age at the time of operation, and the more intense the AChE activity in rectal suction biopsy, the more proximal was the extent of increased AChE activity. Proximal extension of the mucosal AChE activity showed no clear relationship to the creation of a colostomy or to the occurrence of preoperative enterocolitis.

Acetylcholinesterase↗
PubMed1985

In-vitro and in-vivo activities of a novel cephamycin MT-141 against the Bacteroides fragilis group in comparison with six cephem antibiotics.

MT-141 inhibited 90% of the clinical isolates of Bacteroides fragilis at 3.13 mg/l, whereas six reference cephem antibiotics inhibited them at 12.5- greater than 100 mg/l. MT-141 was stable to the Bacteroides beta-lactamases, but the stability alone could not explain the potent activity of MT-141 against the other Bacteroides spp., which produced only small amounts of beta-lactamase, but were resistant to other cephem antibiotics. MT-141 exhibited a higher killing rate and more potent in-vivo efficacy than the reference cephem antibiotics against Bact. fragilis No. 36 combined with Escherichia coli No. 29. In conclusion, the in-vitro and in-vivo anti-bacteroides activities of MT-141 ranked first among those of the cephem antibiotics compared.

Animals↗
PubMed1985

Dephosphorylation of microtubule-associated protein 2, tau factor, and tubulin by calcineurin.

Calcineurin dephosphorylated microtubule-associated protein 2 (MAP2) and tau factor phosphorylated by cyclic AMP-dependent and Ca2+, calmodulin-dependent protein kinases from the brain. Tubulin, only phosphorylated by the Ca2+, calmodulin-dependent protein kinase, served as substrate for calcineurin. The concentrations of calmodulin required to give half-maximal activation of calcineurin were 21 and 16 nM with MAP2 and tau factor as substrates, respectively. The Km and Vmax values were in ranges of 1-3 microM and 0.4-1.7 mumol/mg/min, respectively, for MAP2 and tau factor. The Km value for tubulin was in a similar range, but the Vmax value was lower. The peptide map analysis revealed that calcineurin dephosphorylated MAP2 and tau factor universally, but not in a site-specific manner. The autophosphorylated Ca2+, calmodulin-dependent protein kinase was not dephosphorylated by calcineurin. These results suggest that calcineurin plays an important role in the functions of microtubules via dephosphorylation.

Animals↗
PubMed1985

Ca2+, calmodulin-dependent regulation of microtubule formation via phosphorylation of microtubule-associated protein 2, tau factor, and tubulin, and comparison with the cyclic AMP-dependent phosphorylation.

Isolated microtubule-associated protein 2 (MAP2), tau factor, and tubulin were phosphorylated by a purified Ca2+, calmodulin-dependent protein kinase (640K enzyme) from rat brain. The phosphorylation of MAP2 and tau factor separately induced the inhibition of microtubule assembly, in accordance with the degree. Tubulin phosphorylation by the 640K enzyme induced the inhibition of microtubule assembly, whereas the effect of tubulin phosphorylation by the catalytic subunit was undetectable. The effects of tubulin and MAPs phosphorylation on microtubule assembly were greater than that of either tubulin or MAPs phosphorylation. Because MAP2, tau factor, and tubulin were also phosphorylated by the catalytic subunit of type-II cyclic AMP-dependent protein kinase from rat brain, the kinetic properties and phosphorylation sites were compared. The amount of phosphate incorporated into each microtubule protein was three to five times higher by the 640K enzyme than by the catalytic subunit. The Km values of the 640K enzyme for microtubule proteins were four to 24 times lower than those of the catalytic subunit. The peptide mapping analysis showed that the 640K enzyme and the catalytic subunit incorporated phosphate into different sites on MAP2, tau factor, and tubulin. Investigation of phosphoamino acids revealed that only the seryl residue was phosphorylated by the catalytic subunit, whereas both seryl and threonyl residues were phosphorylated by the 640K enzyme. These data suggest that the Ca2+, calmodulin system via phosphorylation of MAP2, tau factor, and tubulin by the 640K enzyme is more effective than the cyclic AMP system on the regulation of microtubule assembly.

Animals↗
PubMed1985

Reduction of antigen-induced contraction of sensitized guinea-pig tracheal smooth muscle in vitro by calmodulin inhibitors.

The effect of two calmodulin inhibitors, 1-[bis(p-chlorophenyl)methyl]-3-[2,4-dichloro-beta-(2,4-dichlorobenzylox y) phenethyl]imidazolinium chloride (R 24571) and chlorpromazine (CPZ) on antigen-induced contraction of guinea-pig tracheal smooth muscle was studied. Ketotifen, an anti-allergic compound, was used as a comparative drug. Contraction of sensitized guinea-pig trachea induced by antigen challenge was reduced by all three agents. The two calmodulin inhibitors effected relaxation of contraction of guinea-pig trachea induced by histamine and leukotriene D4 (LTD4). Ketotifen relaxed histamine-induced contraction, but hardly affected LTD4-induced tone. Contrary to chemical mediator induced tone, all examined agents had no effect on resting tone. These three agents shifted histamine- and LTD4-induced concentration-contraction curves to the right. They produced a downward displacement of the maximum, without a parallel shift in histamine- and LTD4-induced concentration-contraction curves. The two calmodulin inhibitors did not affect the antigen-induced release of histamine and SRS-A from sensitized guinea-pig lung tissue. Ketotifen slightly inhibited the release of histamine. These results suggest that R 24571 and CPZ, calmodulin inhibitors, reduced an antigen-induced contraction of sensitized guinea-pig trachea in vitro mainly by affecting the contractility of tracheal smooth muscle by chemical mediators but not by interfering with the release of mediators.

Animals↗
PubMed1985

Pharmacological characterization of mouse ear PCA.

Effects of some antiallergic agents on homologous passive cutaneous anaphylaxis (PCA) in mouse ear were investigated by means of assessing the amount of extravasated dye. Antihistamines (chlorpheniramine and diphenhydramine) and antiserotonins (methysergide and cyproheptadine) suppressed mouse ear PCA significantly. In contrast, an antagonist of slow reacting substance of anaphylaxis (SRS-A) (FPL 55712) and an inhibitor of SRS-A synthesis (AA-861) did not suppress the reaction. beta-Adrenergic stimulants (isoproterenol and salbutamol) and theophylline, which elevate cyclic AMP (cAMP) levels, also suppressed mouse ear PCA significantly. The antiallergic agents, N(3',4'-dimethoxycinnamoyl)anthranilic acid(N-5') and ketotifen suppressed mouse ear PCA significantly, but disodium cromoglycate (DSCG) failed to suppress the reaction.

Albuterol↗
PubMed1985

Product inhibition of aminopyrine N-demethylation in isolated hepatocytes.

The product inhibition of aminopyrine (AM) N-demethylation by 4-monomethylaminoantipyrine (MAA) was examined in vitro in preparations of isolated rat hepatocytes using gas chromatograph-mass spectrometer (GC-MS). The kinetic study for AM N-demethylation, which was determined by MAA formation, was studied at concentrations from 0.2 to 4.0 mM with or without various concentrations of D3-MAA. D3-MAA inhibited AM N-demethylation non-competitively at concentrations of 0.2 to 1.0 mM of AM (Ki = 0.81 mM), though it did competitively at concentrations of 1.0 to 4.0 mM of AM (Ki = 0.81 mM). From the present observation, it was suggested that the inhibition type of AM N-demethylation by D3-MAA was dependent on the substrate (AM) concentration.

Aminopyrine↗
PubMed1985

Preparation and biopharmaceutical evaluation of microcapsules of ampicillin.

Microencapsulation of ampicillin, an orally administered antibiotic, with different viscosity grades of ethyl cellulose was studied. The preparation of microcapsules was done as follows; the mixture of ethyl cellulose-CH2Cl2-ampicillin was dispersed in purified water containing 0.5% (w/w) sodium lauryl benzenesulfonate, and then CH2Cl2 was dried out by elevating the temperature. The dissolution curves for the release of ampicillin from microcapsules prepared using the four different viscosity grades of ethyl cellulose were quite different. The release of ampicillin increased with decreasing ethyl cellulose viscosity. The evaluation of prepared microcapsules was made using gastric-emptying-controlled rabbits. The plasma concentration of ampicillin obtained by the administration of microcapsules showed a significant sustained-release pattern. The area under the plasma concentration curve (AUC) of ampicillin obtained after a single oral administration of microcapsules prepared using 10 cps ethyl cellulose was 1.8 times greater than that obtained after double oral administration of powder. This fact will be caused by the delaying of gastric-emptying, intestinal-transit and dissolution of ampicillin there. It was confirmed that a large number of microcapsules still remained in the stomach and each microcapsules still contained ampicillin at 24 h after dosing from the experiment using gastric-emptying-controlled rabbits.

Ampicillin↗
PubMed1985

Displacing effects of chenodeoxycholic acid, ursodeoxycholic acid and sulfadimethoxine on plasma protein binding of tolbutamide.

The interactions between chenodeoxycholic acid (CDCA) or ursodeoxycholic acid (UDCA) and tolbutamide including its displacement from plasma protein binding sites were investigated pharmacokinetically. An increasing concentration of unbound tolbutamide was observed in the in vitro experiment, conducted by equilibrium dialysis method at 30 degrees C after the addition of CDCA and UDCA to human serum albumin (HSA), bovine serum albumin (BSA) and rabbit plasma containing tolbutamide. Small changes in total plasma concentration of tolbutamide were noted after high dose (0.167 mg/kg/min) intravenous infusion of CDCA to rabbits receiving a constant intravenous infusion of tolbutamide, but, such an observation was not obtained with low dose (0.083 mg/kg/min) of CDCA or with either high or low dose of UDCA. These results seem to indicate the displacement of high doses of CDCA. The coadministration of sulfadimethoxine which not only displaces tolbutamide from binding sites but also inhibits its metabolism was investigated. A different plasma pattern was obtained under the same intravenous infusion conditions, as compared with the plasma pattern resulting from tolbutamide-CDCA or UDCA combination.

Animals↗
PubMed1985

Immunoglobulin E antibody production against house dust mite, Dermatophagoides farinae, in mice.

Immunoglobulin E (IgE) antibody production against Dermatophagoides farinae extract (mite antigen) was studied in female BALB/c mice. When mice were immunized with mite antigen and aluminium hydroxide gel (alum) intraperitoneally at intervals of 30 d, good primary, secondary and tertiary IgE antibody responses were observed. In the absence of adjuvant, a subcutaneous injection of mite antigen failed to induce the primary IgE antibody response. However, good IgE antibody responses were observed after the secondary immunization given 30 d after the primary immunization. Furthermore, 5 weekly injections of mite antigen alone also induced the IgE antibody production. Intranasal administrations of mite antigen alone also induced the IgE antibody production in mice. Two exposures to mite antigen, intranasally, were sufficient for eliciting low IgE antibody production. The response was significantly potentiated by the administration of islet-activating protein obtained from culture fluids of Bordetella pertussis. These results indicate that the intranasal administration of mite antigen is very effective for eliciting the IgE antibody production.

Adjuvants, Immunologic↗
PubMed1985

The results of microbial mutation test for forty-three industrial chemicals.

The mutagenicity of 43 industrial chemicals in Salmonella typhimurium (TA98, TA100, TA1535, TA1537, and TA1538) and Escherichia coli (WP2uvrA) was examined. The output of these chemicals in Japan is more than a million kilograms per year. The mutation test was carried out under the condition of absence and presence of rat microsomal activation. Two chemicals, hexamethylenetetramine and 4,4'-methylenediphenyldiisocyanate, showed mutagenic activity in S. typhimurium TA98 and TA100 by metabolic activation. Hexamethylenetetramine also showed mutagenic activity in TA98 without microsomal activation. No mutagenic activity was observed in the 41 chemicals including 4 volatile and gaseous compounds.

Cyanates↗