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Biomedical subjects

T Nakabayashi

Publications and source records attributed to T Nakabayashi.

At least 145 records · Page 8Linked to original sources
PubMed1985

Acid ATPase from chicken liver lysosomes. II. Presence of metal ion-activated enzyme.

Metal ion-activated acid ATPase was present in chicken liver lysosomes. The enzyme catalyzed the hydrolysis of nucleoside tri-, di-, and monophosphates and cleaved the phosphodiester linkage. Among the substrates studied, ATP was hydrolyzed at the highest rate at pH 5.4. The enzyme activity was stimulated 3.5 approximately 7.5-fold by divalent cations such as Ca2+, Mg2+, and Zn2+, but inhibited by EDTA or Hg2+.

Adenosine Triphosphatases↗
PubMed1985

Comparative studies on surface antigenicity of Trypanosoma cruzi trypomastigotes from infected mouse blood and infected L-cell cultures.

Differences in the antigenicities of surface components of blood-form trypomastigotes and trypomastigotes derived from L-cell cultures were studied by agglutination and indirect immunofluorescent tests on living parasites using various antisera from rabbits and mice. Antisera from rabbits immunized with L-cell-derived trypomastigotes and antisera obtained from rabbits infected with L-cell-derived trypomastigotes showed similar titers in both the agglutination and immunofluorescent test. Moreover, both antisera exhibited higher titers against trypomastigotes derived from L-cell cultures than against blood-form trypomastigotes. No detectable agglutination titer against either blood-form or L-cell-derived trypomastigotes was observed with sera from (a) mice infected with blood-form trypomastigotes after previous immunization with blood-form trypomastigotes, (b) mice infected with blood-form trypomastigotes and then treated with Lampit, or (c) mice infected with slightly less virulent trypomastigotes from L-cells. However, detectable and almost equal titers were observed with sera from (a), (b) and (c) in indirect immunofluorescent tests. Mouse sera also exhibited higher titers against trypomastigotes derived from L-cells than against the blood-form type. However, mouse sera showed more pronounced differences than rabbit sera. These results suggest that there may be two types of trypomastigotes in infected animals and that the surface components of blood-form trypomastigotes have lower antigenicity.

Agglutination Tests↗
PubMed1984

Acetylcholinesterase release from mammalian erythrocytes by phosphatidylinositol-specific phospholipase C of Bacillus thuringiensis and characterization of the released enzyme.

The mode of acetylcholinesterase release from mammalian erythrocyte membranes by the action of phosphatidylinositol(PI)-specific phospholipase C of Bacillus thuringiensis was studied. As regards intact erythrocytes, a larger amount of acetylcholinesterase was released from sheep or bovine erythrocytes than from horse erythrocytes. From horse erythrocyte ghosts, acetylcholinesterase was more easily released than from intact cells. Bovine erythrocyte acetylcholinesterase released by PI-specific phospholipase C was purified by column chromatography on DEAE-cellulose, affinity gel and Sepharose 6B, to a homogeneous state, as indicated by polyacrylamide gel electrophoresis, with a recovery of 39%. Also, bovine erythrocyte acetylcholinesterase was solubilized by Triton X-100 and partially purified. The properties of these acetylcholinesterase preparations obtained by the action of PI-specific phospholipase C and/or Triton X-100 were studied in detail. On elution from the Sepharose 6B column, Triton X-100-solubilized acetylcholinesterase was eluted at the void volume while the enzyme obtained by further treatment with PI-specific phospholipase C was eluted in the region corresponding to M.W. 250,000. Furthermore, the heat stability of acetylcholinesterase purified after solubilization with PI-specific phospholipase C was higher than that of the Triton X-100-solubilized acetylcholinesterase. The close association and direct interaction of PI with acetylcholinesterase in the erythrocyte membrane was suggested by the above results.

Acetylcholinesterase↗
PubMed1984

Release of alkaline phosphodiesterase I from rat kidney plasma membrane produced by the phosphatidylinositol-specific phospholipase C of Bacillus thuringiensis.

The release of plasma-membrane-bound enzymes by phosphatidylinositol-specific phospholipase C obtained from Bacillus thuringiensis was investigated. Among the ectoenzymes of plasma membrane tested, alkaline phosphodiesterase I was released markedly from rat kidney cortex slices, in addition to alkaline phosphatase and 5'-nucleotidase. Other membrane-bound enzymes; alanine aminopeptidase, leucine aminopeptidase, dipeptidyl peptidase, leucine aminopeptidase, dipeptidyl peptidase IV, esterase and gamma-glutamyl transpeptidase could not be liberated from the treated slices. Alkaline phosphodiesterase I was released linearly from rat kidney slices with the concentration of phosphatidylinositol-specific phospholipase C, but little enzyme was released from rat liver slices. Alkaline phosphodiesterase I separated from kidney tissue with n-butanol still retained phosphatidylinositol and was transformed into a lower molecular weight form by phosphatidylinositol-specific phospholipase C. This suggests an important function for phosphatidylinositol in the binding of alkaline phosphodiesterase I to the plasma membrane of rat kidney cells. The alkaline phosphodiesterase I released from rat kidney had a molecular weight of about 240,000 and an isoelectric point (pI) of 5.4. The enzyme hydrolyzed the phosphodiester linkage of p-nitrophenyl-thymidine 5'-monophosphate at pH 8.9 and had a Km value of 0.3 mM. The enzyme was activated by Mg2+ and Ca2+, but was inhibited by EDTA. Strong inhibition took place on the addition of adenosine 5'-phosphosulfate or the nucleotide pyrophosphates, i.e., UDP-galactose and alpha, beta-methylene ATP.

Animals↗
PubMed1984

Method for ejecting cestodes: duodenal tube injection of gastrografin.

Most of the conventional anthelmintics for cestodiasis are known to destroy the worm body. The risk of cysticercosis and recurrence of cestodiasis will be avoided only if tapeworms are ejected with intact bodies and scoleces . Two cases with Diphyllobothrium latum and two with Taenia saginata were treated by administration of 200-300 ml of Gastrografin through a duodenal tube. The worm bodies were confirmed by fluoroscopy, and the expelled worms were alive and had intact scoleces . No adverse effects were noted in the patients during or after the treatment.

Adult↗
PubMed1984

Phosphatidylinositol-hydrolyzing enzymes in chicken liver cells.

Phosphatidylinositol-hydrolyzing activities were found in mitochondrial, lysosomal, microsomal, and cytosol fractions of chicken liver. At least two different activities were detected; cytosolic activiti(es) was maximally exhibited around pH 6.0, activated by Ca2+, and inhibited by EDTA; whereas lysosomal activiti(es) had a optimal pH 5.0, being unaffected by Ca2+ or EDTA.

Animals↗
PubMed1984

Delayed secondary immune response in mice immunized with Toxoplasma antigens and its effect for protection against Toxoplasma gondii.

Primary immune response by mice immunized with Toxoplasma peritoneal exudate (PE) was produced slowly at a low level. To induce high Toxoplasma antibodies, mice should be boostered after the primary immune response reached the peak in 4 weeks or later. Immunization of mice with PE alone in 4 weeks could suppress the growth of Toxoplasma but could not accomplish protection. Two of 9 mice immunized with PE in complete Freund's adjuvant (CFA), and 16 of 27 mice immunized with PE containing Toxoplasma ( ToxoPE ) in CFA were protected against a challenge of 1 X 10(3) Toxoplasma, RH strain. The mice surviving to the challenge showed complete protection against a rechallenge of higher dose, 1 X 10(6) RH strain. Their ascites were very high in LA titer and would be a great source for obtaining high titer antibodies to Toxoplasma without contamination of host serum components. Biological characters of Toxoplasma, RH strain, in chronic infection of mice are discussed.

Animals↗
PubMed1983

Complete purification of phosphatidylinositol-specific phospholipase C from a strain of Bacillus thuringiensis.

A phosphatidylinositol-specific phospholipase C was purified from the culture broth of Bacillus thuringiensis IAM 12077 to a homogeneous state as revealed by polyacrylamide gel electrophoresis. The specific activity of the purified enzyme was 559 units/mg and recovery of the enzyme activity was 31%. Molecular and physiological properties of the purified enzyme, including molecular weight (22,000), isoelectric point (pI = 4.9) and its ectoenzyme-releasing activity, were studied in comparison with those other known enzymes of bacterial origin.

Bacillus thuringiensis↗
PubMed1983

Electron microscopic observations on alterations in cultured Plasmodium falciparum and infected erythrocytes after treatment with cyclic AMP in vitro.

The fine structure of Plasmodium falciparum treated with cyclic AMP in vitro was studied. Cyclic AMP stimulated the appearance of membranous structures in P. falciparum-infected erythrocytes. Two types of membranous structures originating from the host cell were observed: multilaminate membranous structures and multistranded layer-like membranous structures. The multilaminate structures may play a role in gametocytogenesis and the maturation of the gametocyte. The multilaminate structures were either free in the cytoplasm of infected erythrocytes or present in association with the parasitophorous vacuole membrane surrounding immature gametocytes. These structures may originate from the erythrocyte plasma membrane and the parasitophorous vacuole membrane. Other notable findings in P. falciparum treated with cyclic AMP included the presence of loop-like membrane structures protruding from the plasma membrane of the parasite and termination of some plasma membranes of the parasite in dense granular structures.

Cell Membrane↗
PubMed1983

Improved method for separation on CM-cellulose of the trypomastigote form of Trypanosoma cruzi from forms grown in fibroblast cell cultures.

Trypomastigotes grown in fibroblast cell (L-cell) culture were more effectively and more rapidly separated from other cells on a CM-cellulose column with culture medium (MEM with 10% calf serum) for elution instead of phosphate-saline-glucose buffer (PSG). This effective separation was shown to be due to the presence of serum. Trypomastigotes weakly adhered to CM-cellulose resin by the tip of the body (mainly the flagellar tip) when they were suspended with CM-cellulose resin in PSG. Serum seemed to disturb the adhesion of trypomastigotes to the resin, but not the adhesion of amastigotes and fibroblast cells. Therefore, only trypomastigotes were rapidly eluted from a CM-cellulose column in the presence of serum.

Animals↗
PubMed1983

Studies on the surface component of Trypanosoma cruzi amastigotes: determination of the specific antigen and characterization by enzyme treatment and electronmicroscopy.

A specific antigen to amastigotes of Trypanosoma cruzi was found by immunodiffusion. It was one of the predominant antigens against anti-amastigote serum and also against infected rabbit serum. This specific antigen was mainly eluted in the first peak from a Sephadex G-200 column and moved slowly on immunoelectrophoresis. It was shown to be present on the surface of amastigotes using antiserum to the specific precipitin line between the first fraction of amastigote antigen from the Sephadex G-200 column and the anti-amastigote serum. The surface component of amastigotes was found to be rich in carbohydrate by histochemical electronmicroscopy. The component was also shown to be susceptible to pronase and hyaluronidase, but resistant to trypsin, chondroitinase ABC and neuraminidase, by investigating the sensitivity to the lytic effect of fresh serum from unimmunized rabbits after enzyme treatment. The relation between the specific antigen and the surface component was discussed.

Animals↗
PubMed1983

Comparative studies on trypomastigotes of Trypanosoma cruzi from infected mouse blood and infected fibroblast cell (L-cell) culture.

The resistance to phagocytosis by macrophages and the penetration into fibroblast cells of blood form trypomastigotes of Trypanosoma cruzi were compared with those of trypomastigotes grown in fibroblast cell culture. On incubation for 24 h, blood form trypomastigotes were almost completely resistant to phagocytosis, but about 40% of the trypomastigotes from cell culture were phagocytized. On longer incubation, the resistance of both forms of trypomastigotes decreased gradually. The penetrating ability of blood form trypomastigotes was much lower than that of trypomastigotes from cell culture. Infection of mice with blood form trypomastigotes resulted in less proliferation of parasites in the liver and spleen than that with trypomastigotes from cell culture. From these results, the existence of two functionally different forms of trypomastigotes in infected mice and in infected fibroblast cell culture, respectively, is discussed.

Animals↗
PubMed1982

[Experience with high-dose methotrexate therapy for malignant solid tumors].

Thirteen patients with malignant solid tumors, mainly osteogenic sarcomas, were treated by high-dose MTX therapy, 50-400 mg/kg, in a total of 72 cycles. It has been proved that this therapy was relatively safe provided careful clinical surveillance were assured. Of 8 patients with osteogenic sarcomas, 6 had no metastatic lesions on the chest X-rays before this therapy: three were alive without any evidence of disease for 18-25 months after high-dose MTX therapy. In some cases of other malignant solid tumors, particularly intracranial tumors, clinical efficacy was observed. Dose-time relationships, etc. should further be studied for more therapeutic efficacies of high-dose MTX therapy.

Adolescent↗
PubMed1981

Protective reaction against malaria infection in mice sensitized with Frozen-thawed toxoplasma tachyzoites.

Mice sensitized with frozen-thawed Toxoplasma antigen emulsified in Freund's Incomplete Adjuvant (FIA) showed high resistance against Plasmodium berghei infection, but not in mice sensitized with paraformaldehyde-fixed. Toxoplasma or saline plus FIA. However, mice which survived from malaria infection did not show any protective reaction against the RH strain inoculation. Furthermore, an immune interferon activity was detected in the supernatant of the spleen cells collected from the mice sensitized with frozen-thawed Toxoplasma and cultured with the specific antigen, however, no Toxoplasma growth inhibitory factor (Toxo-GIF) was found in the same supernatant of lymphokines. From these results, it is suggested strongly that frozen-thawed Toxoplasma antigen could confer nonspecific resistance in mice against Plasmodium infection.

Animals↗