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Biomedical subjects

K Ohashi

Publications and source records attributed to K Ohashi.

At least 541 records · Page 30Linked to original sources
PubMed1986

Monoclonal antibody to chicken fetal antigen on Marek's disease lymphoblastoid cell line MDCC-MSB1.

A monoclonal antibody (2H3) to chicken fetal antigen (CFA) expressed on the cell surface of the Marek's disease lymphoblastoid cell line MDCC-MSB1 was generated. 2H3 reacted specifically with various cells from chicken embryos, especially with fetal red blood cells, fetal bursa-derived lymphocytes, fetal liver cells, and embryo fibroblasts but not with fetal peripheral blood lymphocytes. 2H3 reacted also with all lymphoblastoid cell line cells tested: Marek's disease, avian leukosis, and reticuloendotheliosis line cells. On the basis of 2H3 specificity, CFA detected by 2H3 seemed to be similar to chicken fetal red blood cell antigen previously reported, but not to chicken alpha-fetoprotein. A transient increase of reactivities with 2H3 was observed in lymphocytes prepared from thymus, spleen, and bursa of chickens inoculated with Marek's disease virus or herpesvirus of turkeys from 7 to 21 days postinoculation. The average percentage of CFA-positive cells in lymphoid cells from Marek's disease virus-infected chickens at the peaks was higher than that of the cells in Marek's disease tumor cells from 146- and 156-day-old chickens in the field. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting analysis revealed that the monoclonal 2H3 is recognized a Mr 50,000 oncodevelopmental cell surface antigen present on MDCC-MSB1 cells. The possible differences between CFA detected by 2H3 and chicken fetal red blood cell antigen expressed on normal chicken fetal erythrocytes are discussed.

Animals↗
PubMed1985

Characterization of an enzyme which catalyzes isomerization and epimerization of D-erythrose 4-phosphate.

The enzyme which catalyzes the conversion of D-erythrose 4-phosphate to D-erythrulose 4-phosphate and D-threose 4-phosphate has been purified to homogeneity from a crude extract of beef liver. Analysis of the purified enzyme by Sephadex G-100 gel filtration and sodium dodecyl sulfate/polyacrylamide gel electrophoresis revealed it to be a dimer of relative molecular mass 43 000. From the gas chromatography/mas spectrometry analyses of the enzymatic reaction products, it appeared that about 90% of the total amount of tetrose 4-phosphate was present as D-erythrulose 4-phosphate after equilibration. The purified enzyme, which is tentatively called 'erythrose-4-phosphate isomerase' had no significant isomerase activities on D-glyceraldehyde 3-phosphate, D-ribose 5-phosphate, D-glucose 6-phosphate and D-fructose 6-phosphate, but a strong D-ribulose-5-phosphate 3-epimerase activity was co-purified with the erythrose-4-phosphate isomerase activity through every step in the isolation. Both the erythrose-4-phosphate isomerase and D-ribulose-5-phosphate 3-epimerase activities were inactivated at the same rate at the elevated temperature, and also inhibited to the same extent by various inhibitors. It is likely, that both activities are catalyzed by the single enzyme protein.

Animals↗
PubMed1985

The quaternary structure and activity of newly purified fatty acid synthetase from the Harderian gland of guinea-pig.

Fatty acid synthetase was isolated from the Harderian gland of guinea-pig. The fatty acids synthesized by the purified enzyme were analyzed by mass fragmentography. The purified enzyme had an inherent capacity to utilize methylmalonyl-CoA and synthesize methyl-branched fatty acids. Physicochemical studies indicated that an active enzyme was a dimer, consisted of two subunits of Mr = 2.5 X 10(5). The negatively stained enzyme had an electron micrographic image of an ellipsoidal contour with a continuous middle cleft along the major axis. The major and minor axes were approximately equal to 220 and 150 A, respectively. In a dimer, the subunit had a rod-like structure about 220 A long and 50 A wide. The enzyme was inactivated and dissociated into subunits by incubation at 0 degree C. The inactivated enzyme was fully reactivated by raising the temperature of the solution. The relationship between the quaternary structure of the enzyme and the occurrence of enzymatic activity was studied by high-performance liquid chromatography. Neither active monomers nor inactive dimers were found in inactivation and reactivation processes. The initial velocity of reactivation was proportional to the enzyme concentration over a concentration range of 160-800 micrograms/ml, indicating that the rate-determining step in the reactivation reaction was unimolecular.

Amino Acids↗
PubMed1985

Sclerotic changes around the endolymphatic sac in human temporal bones.

We used light microscopy to study 87 human temporal bones (from 47 cases) with no known otological disorders, and found that certain cases had sclerotic changes around the endolymphatic duct and sac. Changes included fibrosis, hyalinization, psammoma formation, and thickened vascular walls. The findings were subjected to statistical analysis, which indicated that most of the changes could be positively correlated with increases in age.

Adolescent↗
PubMed1985

Ontogeny of the transplantation immunity of mice for rejecting ascitic allogeneic tumors.

Ontogeny of the murine transplantation immunity for rejecting ascitic allogeneic tumors (chemically-induced RG lymphoma and L1210 leukemia) as a model of in vivo cytotoxic T cell immunity was studied. Challenge by 10(6) to 10(7) allogeneic tumor cells per 20 g body weight (b.w.) of the mouse was fatal to 1-3 day-old mice, whereas 7-30 day-old mice rejected the tumor. In newborn mice however some yet undetermined mechanism worked to temporally depress the initial tumor growth. Injection of low (10(6) cells per 20 g b.w.) to moderate (10(7)) doses of semiallogeneic spleen cells into newborn mice prepared for second set rejection of the tumor carrying the same alloantigens as the spleen cells, although injection of high dose (3 X 10(8)) cells reduced the tumor rejecting immunity. This second set rejection occurred even against the allogeneic tumor inoculated as early as 3 days old, if the mice had been primed with the alloantigens at birth. It appears therefore that newborn and early suckling mice are protected from tumor invasion by cytotoxic immunity more powerfully than expected from earlier in vitro works.

Age Factors↗
PubMed1985

Connectin filaments link thick filaments and Z lines in frog skeletal muscle as revealed by immunoelectron microscopy.

In an earlier study connectin, an elastic protein of striated muscle, was found to be associated with "gap filaments" originating from the thick filaments in the myofibril, but it was not clear whether it extends to Z lines or not (Maruyama, K., H. Sawada, S. Kimura, K. Ohashi, H. Higuchi, and Y. Umazume, 1984, J. Cell Biol., 99:1391-1397). In the present immunoelectron microscopic study using polyclonal antibodies against native connectin, we have concluded that the connectin structures are directly linked to Z lines from the thick (myosin) filaments in myofibrils of skinned fibers of frog skeletal muscle. There were five distinct antibody-binding stripes in each half of the A band and two stripes in the A-I junction region. Deposits of antibodies were recognized in I bands and Z lines. We suggest that connectin filaments run alongside the thick filaments, starting from a region approximately 0.15 micron from the center of the A band.

Animals↗
PubMed1985

Assay of fatty acid synthetase by mass fragmentography using [13C]malonyl-CoA.

A new assay method for fatty acid synthetase using mass fragmentography was described. [2-13C]Malonyl-CoA was chemically synthesized from [2-13C]malonic acid and used as a substrate. The newly synthesized fatty acids were quantitated with a GC-MS instrument after methyl esterification. Monitoring of molecular ions of the newly synthesized fatty acids enabled us to determine the absolute amounts with heptadecanoic acid as an internal standard. Multiple products (14 : 0, 16 : 0, and 18 : 0) were measured individually. Using this technique, we obtained information about production profiles such as that of chain length against incubation temperature and about malonyl-CoA decarboxylation activity in enzyme preparations, and we also confirmed the presence of malonyl-CoA decarboxylation activity even in purified fatty acid synthetase from guinea pig Harderian gland. Compared with the conventional assay methods (spectrophotometric and radioisotopic), this method was more reliable and useful.

Acetyl Coenzyme A↗
PubMed1985

I-protein is localized at the junctional region of A-bands and I-bands of chicken fresh myofibrils.

FITC-labeled antibodies raised against chicken myofibrillar I-protein stained chicken myofibrils, which were fixed with formalin immediately after being cut from the sacrificed chicken breast muscle, at the junctional region of A-bands and I-bands. On the other hand, the antibodies stained the glycerinated myofibrils at the region around Z-bands. Aged glycerinated myofibrils stored in a cold room became stained with the same antibodies at the M-line and the A-band region except for the H-zone and the Z-band. I-Protein, which was originally localized at the A-I junctions, moved to the region around Z-bands and A-bands during the process of preparing myofibrils, paralleling the deterioration of myofibrils. Although I-protein is easily released from its original position, it is not a cytoplasmic protein of muscle but an intrinsic myofibrillar component, because immunoblotting tests showed that I-protein is contained in the myofibrillar fraction and not in the muscular cytoplasmic fraction.

Animals↗
PubMed1985

Isolation and biological activities of limulus anticoagulant (anti-LPS factor) which interacts with lipopolysaccharide (LPS).

Exposure of limulus hemocytes to bacterial endotoxins (lipopolysaccharide, LPS) results in the activation of the intracellular clotting system, consisting of several protein components. During the separation of these components, a potent anticoagulant, named anti-LPS factor, which inhibits the endotoxin-mediated activation of the coagulation cascade, was found in hemocytes from both Tachypleus tridentatus and Limulus polyphemus (Tanaka, S., et al. (1982) Biochem. Biophys. Res. Commun. 105, 717-723). The principle isolated from the Tachypleus hemocyte lysate by column chromatographies on dextran sulfate-Sepharose CL-6B and Sephadex G-50 under sterile conditions was a simple basic protein with an apparent molecular weight of 15,000. It consisted of a single chain polypeptide containing a total of 128 amino acids. The COOH-terminal end was presumed to be histidine, but no NH2-terminal end reactive to phenylisothiocyanate was detected. The isolated anti-LPS factor specifically inhibited the endotoxin-mediated activation of factor C, which has recently been identified as an LPS-sensitive serine protease zymogen in the hemocytes. This inhibition appeared to be due to the binding of anti-LPS factor with LPS. Moreover, anti-LPS factor had an antibacterial effect on the growth of Gram-negative bacteria (Salmonella minnesota R595 and 1114W) but not on that of Gram-positive bacteria (Staphylococcus aureus 209P). These biological activities of the isolated anti-LPS factor suggest an important role in cellular defence of limulus against microbial invasion.

Amino Acids↗
PubMed1985

Statoconia displacement in squirrel monkey ears.

When findings in squirrel monkey temporal bones after streptomycin sulfate intoxication were compared with those after application of intense linear acceleration, the dislocated utricular statoconia were more frequently found around the cupula of the crista ampullaris posterior in the latter group, whereas statoconia were rather widely disseminated within three semicircular canals (cupula, ampulla, and duct) after streptomycin intoxication. This difference is most probably due to the fact that, in the linear acceleration group, normal statoconia were instantaneously dislodged in a block (or forming a large-sized mass) and thereafter moved in the gravity direction, whereas in the streptomycin group, degenerated statoconia formed smaller groups and were more freely disseminated. In the endolymphatic sac, dislocated statoconia were readily phagocytosed by the epithelium of the intermediate portion and rugous portion (and transitory portion). The incidence of phagocytosis was found more in the streptomycin group, compared to the linear acceleration group.

Acceleration↗
PubMed1985

[Tissue polypeptide antigen as a tumor marker for gynecologic malignancies].

Tissue polypeptide antigen (TPA) was measured by radioimmunoassay in sera from 413 patients with various gynecologic tumors. The distribution of positive values (greater than 102 U/l) in the patients with gynecologic malignancies was such that the percentage of patients with elevated values appeared to increase with advancing stages of disease. Among the cervical cancer patients, elevated TPA values were observed in 11% of preinvasive, 35% of stage I and 67% of advanced cases. Similarly, the TPA values were elevated in 35% of the endometrial cancer patients. Among the patients with ovarian malignancies, serum TPA was elevated in 33% of borderline, 47% of stage I and 86% of advanced cases. However, serum TPA was elevated in 21% of patients with uterine myomas and in 12% of those with ovarian benign tumors. The serial measurements of TPA in sera of the patients with gynecologic malignancies showed that serum TPA levels correlated with the effect of treatment and the clinical courses. The present observations demonstrate that the lack of tumor specificity of TPA limits its diagnostic value in gynecologic malignancies but that serial measurements of this antigen appear to be useful for monitoring of patients.

Adult↗
PubMed1984

Anti-LPS factor in the horseshoe crab, Tachypleus tridentatus. Its hemolytic activity on the red blood cell sensitized with lipopolysaccharide.

Anti-LPS factor, which inhibits the endotoxin mediated coagulation system in the horseshoe crab, Tachypleus tridentatus, was found to lyse red blood cells sensitized with gram-negative bacterial LPS, but not to lyse unsensitized cells. This hemolysis occurred even at 0 degree C and was completed within 1 min. The binding of anti-LPS factor to LPS must be essential for the hemolysis, because free LPS inhibited the hemolytic action of anti-LPS factor.

Animals↗
PubMed1984

Enzymatic isomerization and epimerization of D-erythrose 4-phosphate and its quantitative analysis by gas chromatography/mass spectrometry.

An enzyme preparation from beef liver catalyzed the isomerization and epimerization of D-erythrose 4-phosphate to D-erythrulose 4-phosphate and D-threose 4-phosphate. The presence of D-erythrulose 4-phosphate and D-threose 4-phosphate was demonstrated by several analytical methods. After dephosphorylation, the presence of D-erythrulose and D-threose was confirmed by thin-layer chromatography, gas-liquid chromatography and an enzymatic method depending upon D-erythrulose reductase. The enzymatic products were also identified and simultaneously quantitated by a new procedure using gas chromatography/mass spectrometry. Each of three tetroses was distinguished by the combination of the reduction with sodium borodeuteride and the determination of relative intensities of the ion pairs m/z 379 and 380 of sugar tetritol trifluoroacetate. By gas chromatography/mass spectrometry, we observed that D-threose 4-phosphate was also converted into D-erythrulose 4-phosphate and D-erythrose 4-phosphate. At the equilibrium, about 90% of the tetrose 4-phosphate existed in the form of D-erythrulose 4-phosphate. On the basis of gas chromatography/mass spectrometric evidence together with gas chromatographic and thin-layer chromatographic patterns, it is suggested that the single enzyme of the beef liver catalyzed both reactions of isomerization and epimerization of aldotetrose 4-phosphate.

Animals↗