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Biomedical subjects

K Taniguchi

Publications and source records attributed to K Taniguchi.

At least 865 records · Page 48Linked to original sources
PubMed1984

Studies on the activity of Obioactin with acetylspiramycin on mice infected with Toxoplasma gondii.

In acutely infected mice, acetylspiramycin (ASPM) administered in combination with Obioactin , or sulfamethoxypyrazine ( SMPZ ), prevented Toxoplasma organisms from encysting in the brain and heart tissues. When administered alone, ASPM prevented these organisms from encysting in the heart but not in the brain. All the regimens used failed to reduce the bulk of parasites in the brain and heart tissues of chronically infected mice. Treatment with an ASPM- Obioactin combination, however, brought about the most remarkable reduction, or 52.4%, of the cyst count in the brain of all the methods of treatment applied. Light and electron microscopy of the mice with chronic Toxoplasma infection revealed no changes in the brain or heart tissue of the ASPM- Obioactin treated mice and degenerative changes in the cyst wall and bradyzoites and a remarkable increase of microglias with cysts in the brain in some of these mice.

Animals↗
PubMed1983

Outbreak of infantile gastroenteritis due to type 40 adenovirus.

Genetic and antigenic characterisation was performed on a strain of adenovirus (EAd) isolated from an outbreak of gastroenteritis which occurred in an orphanage in the City of Sapporo, in the room housing the eldest children, who ranged in age from 14 to 22 months. 7 of the 11 children housed in that room had diarrhoea between July 11 and July 22, 1982. All 7 shed adenoviruses detectable by electron microscopy in their stools. Immune electron microscopy showed that all patients as well as the healthy contacts sharing the room underwent seroconversion to EAd. There was no homology, or very slight homology, between DNA of EAd and those of adenoviruses belonging to subgroups A to E. Antigenically EAd was closely related to type 40 adenovirus, so far the sole member of the newly identified subgroup F. This outbreak of gastroenteritis is the first in which the causative agent has been identified as being a member of subgroup F adenoviruses.

Adenoviridae Infections↗
PubMed1983

Differences in thymus dependency among the alloreactive T-cell subpopulations in their development: graft-versus-host reaction appears to be mediated by delayed-type hypersensitivity of tuberculin type.

The effects of thymectomy at various times after birth, 1 and 7 days (Tx-1, Tx-7), on delayed footpad reactions, cell-mediated cytotoxicity (CMC), production of migration inhibitory factor (MIF), and graft-versus-host reactions (GVHR) against allogeneic antigens were determined by experiments with 8-week-old mice. Delayed footpad reactions were detected in Tx-1 mice, but CMC, production of MIF, and the ability to raise GVHR were not detected in such mice. CMC was detected in Tx-7 mice. However, the ability to raise GVHR and to produce MIF was abolished by thymectomy at 7 days after birth. These results suggest that the effector mechanism to mount a GVHR might be mediated by delayed-type hypersensitivity of tuberculin type rather than CMC to host antigens.

Age Factors↗
PubMed1983

Stopped flow measurement of conformational change induced by phosphorylation in (Na+,K+)-ATPase modified with N-[p-(2-benzimidazolyl)phenyl]maleimide.

The addition of ATP to (Na+,K+)-ATPase (EC 3.6.1.3) of pig kidney modified with N-[p-(2-benzimidazolyl)phenyl]maleimide induced three different modes of fluorescence change: positive, biphasic, and negative, which were observed, respectively, in the presence of Mg2+ with 16 or 160, 320 or 640, and 1500 mM Na+. At 16-320 mM Na+, the extent of positive change was almost saturated at 0.4 microM ATP, but the rate of the change was significantly accelerated by much higher concentrations of ATP. In the presence of 640 mM Na+, the change showed an initial small decrease in fluorescence (t 1/2 = 15 ms), followed by an increase (t 1/2 = 145 ms). The amount of phosphoenzyme increased rapidly and gave a steady level (t 1/2 = 38 ms) after the addition of ATP to give 12.2 microM. Comparison of the relative fluorescence intensity and the amount of phosphoenzyme at a given time permitted modeling the amount of ADP-sensitive phosphoenzyme and K+-sensitive phosphoenzyme present. A simulation gave a good fit to the smoothed data. These data show directly that ATP is hydrolyzed through ADP-sensitive phosphoenzyme and K+-sensitive phosphoenzyme in the presence of Mg2+ and Na+.

Animals↗
PubMed1983

Arachidonate 5-lipoxygenase of guinea pig peritoneal polymorphonuclear leukocytes. Activation by adenosine 5'-triphosphate.

Arachidonate 5-lipoxygenase was isolated from guinea pig peritoneal polymorphonuclear leukocytes, and partially purified from a high speed supernatant of a homogenate. 5-Hydroperoxy-6,8,11,14-eicosatetraenoic acid was a predominant reaction product. The enzyme reaction required specifically calcium ion (20 microM for half-maximal activity), and other divalent cations such as magnesium and cobalt were ineffective. The calcium-dependent 5-lipoxygenase reaction was stimulated by several nucleotides, most prominently by ATP in the order of 1 mM. 5,8,11,14,17-Eicosapentaenoic acid as substrate was as active as arachidonic acid, and was oxygenated at the C-5 position.

Adenosine Triphosphate↗
PubMed1983

Human plasma alpha 1- and alpha 2-thiol proteinase inhibitors strongly inhibit Ca-activated neutral protease from muscle.

Human plasma alpha 1- and alpha 2-thiol proteinase inhibitors (alpha 1,2TPIs) inhibited purified Ca-activated neutral protease (CANP) most strongly among a number of thiol proteinases tested. When CANP was added to plasma, it was also inhibited by alpha 2-macroglobulin (alpha 2M). At low CANP concentrations, CANP was bound mainly to alpha 1,2TPIs; and after saturation of alpha 1,2TPIs the additional CANP was bound to alpha 2M. These data suggested that a probable role of alpha 1,2TPIs is to neutralize the proteolytic activity of the CANP derived from the tissues in collaboration with alpha 2M.

Animals↗
PubMed1983

Thymus-dependent increases in splenic T-cell population by indomethacin.

After administration of indomethacin, an inhibitor of prostaglandin synthesis, the number of splenic T cells increased in normal mice but not in adult-thymectomized or athymic nude mice. The enlarged T-cell population consisted mainly of Lyt-1+2+ cells. This thymus-dependent increase in T-cell population augmented in vivo antibody response to sheep erythrocytes, a T-dependent antigen. The increased T-cell population also included suppressor cells that were eliminated by treatment with anti-Lyt-2 antibody plus complement. These results suggest that increased T cells in the spleen were recruited from the thymus by an indomethacin-mediated mechanism and participated in immune responses as regulator cells.

Animals↗
PubMed1983

Development of immunity against Listeria monocytogenes in athymic nude versus neonatally thymectomized mice.

The thymus requirement for the development of immunological responsiveness was determined by estimation of immune responses raised to Listeria monocytogenes in athymic nude, neonatally thymectomized, and sham-operated mice at 6 weeks of age. Not only sham-operated mice, but also neonatally thymectomized mice could completely eliminate the bacteria from the spleen and liver, while athymic nude mice could not eliminate them and showed a persistent form of infection. A strong delayed footpad reaction and acquired cellular resistance could be raised in neonatally thymectomized mice just as well as in sham-operated mice, but not in athymic nude mice. The delayed footpad reaction could be induced in neonatally thymectomized mice without an accompanying ability to inhibit macrophage migration. These results suggest that T cells responsible for immunity against listerial infection require the presence of the thymus for only a very short period in their development.

Animals↗
PubMed1983

Monoclonal antibodies reactive with different sites of N and H antigenic particles of poliovirus.

We established three hybridomas (designated 2A12, 4C4 and 6H8) secreting monoclonal antibodies which react with N and H(heated) antigenic particles of poliovirus type 1 (Mahoney strain). One of these monoclonal antibodies, 4C4, had virus-neutralizing activity, while the other two were non-neutralizing. A solid-phase radioimmunoassay and a neutralization test indicated that the specificity of the neutralizing monoclonal antibody 4C4 was the same as that of the monospecific antibody HN31, previously prepared by us by absorbing poliovirus antiserum with an equine serum inhibitor-resistant mutant (M-HN31) of poliovirus. Furthermore, by means of immune electron microscopy, it was revealed that the combining site of the 4C4 neutralizing monoclonal antibody is on or around vertices of the N and H antigenic particles, while the other two monoclonal antibodies are directed to the entire surface of the antigens.

Antibodies, Monoclonal↗
PubMed1983

Differentiation and maturation of thy-1 negative bone marrow cells. I. Effects of the thymus and radioresistant helper functions on the maturation of precursor cells specific for heterologous erythrocytes.

The effects of adult thymectomy (ATx) and preimmunization on the differentiation of cells responsible for delayed footpad reaction (DFR), plaque forming cells (PFC) and cell mediated lympholysis (CML) were examined in lethally irradiated and thy-1 negative bone marrow cell reconstituted C57BL/6 recipients. ATx reduced the degrees of immune responses in irradiated and reconstituted mice. When the recipients had been preimmunized, all of DFR, PFC and CML became detectable even in irradiated and reconstituted ATx mice. Preimmunization also evoked early maturation of precursor cells for CML. Therefore, it was suggested that radioresistant helper effects, presumably in the presence of antigens, could promote the differentiation and maturation of T cell precursors in bone marrow in the absence of the thymus. We also demonstrated differences in restoration periods of such responses after lethal irradiation and reconstitution. One or two weeks following irradiation and reconstitution, DFR was first detectable. On the other hand, the generation of PFC was detected later than 2 weeks after bone marrow cell reconstitution, and it took over 4 weeks for thy-1 negative bone marrow cells to raise CML. T cells responsible for DFR may have lower dependency on the thymus than those for PFC and CML.

Allergy and Immunology↗
PubMed1983

The mechanism of reduction of cell-mediated cytotoxicity in neonatally thymectomized mice.

The effect of neonatal thymectomy at various times after birth (Tx-1, Tx-7) on effector and suppressor T cells responsible for cell-mediated cytotoxicity (CMC) for allogenic antigens was determined. Following in-vitro primary mixed lymphocyte cultures, in the absence of T-cell growth factor (TCGF), alloreactive CMC was not detected in spleen cells of Tx-1 mice, but was detected in spleen cells of Tx-7 mice at as high levels as in those of sham-operated mice. However, in the presence of TCGF, as much alloreactive CMC was detected in spleen cells of Tx-1 mice as in those of Tx-7 mice. Furthermore, TCGF production was not detected in spleen cells of Tx-1 mice but was detected in those of Tx-7 mice. In in-vivo experiments, inhibition of allogeneic tumour growth and CMC in spleen cells showed the same pattern as in in-vitro experiments. These results support the concept that the reduction of CMC in Tx-1 mice might be due to a defect in helper function (TCGF-producing capacity) rather than to a defect in cytotoxic T lymphocytes and/or cytotoxic T lymphocyte precursors. Alloreactive suppressor T cells could not be induced in spleen cells of Tx-1 mice but were induced in spleen cells of Tx-7 mice. Therefore, it was suggested that alloreactive suppressor T cells require the presence of the thymus for 7 days after birth in their development.

Animals↗
PubMed1983

Enzyme immunoassay of HBeAg employing beta-D-galactosidase.

An enzyme-linked immunosorbent assay (ELISA) system for hepatitis B e antigen (HBeAg) was developed employing beta-D-galactosidase conjugated with antibody to HBeAg (anti-HBe) and using m-maleimidobenzoyl-N-hydroxysuccinimide ester as the coupling reagent. The experimental conditions for quantitative assay of HBeAg were determined. The presence of rheumatoid factor in test sera did not affect the results. This assay system is more sensitive than the micro-Ouchterlony method and as sensitive as radioimmunoassay. The use of beta-D-galactosidase for ELISA in the field of virology is recommended.

Galactosidases↗