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Biomedical subjects

T Oda

Publications and source records attributed to T Oda.

At least 883 records · Page 49Linked to original sources
PubMed1978

Absence of C-type virus production in human leukemic B cell, T cell and null cell lines.

Electron microscope observation of cultured human leukemic B cell, T cell and null cell lines and reverse transcriptase assay of the culture supernatants were all negative for the presence of C-type virus. Bat cell line, which propagates primate C-type viruses well, was cocultivated with the human leukemic cell lines, in the hope of amplification of virus if present. Three weeks after mixed culture, the culture supernatants were again examined for reverse transcriptase activity and the cells were tested for syncytia formation by cocultivation with rat XC, human KC and RSb cell lines. All these tests, except for the positive control using a simian sarcoma virus, were negative, suggesting that no C-type was produced from these human leukemic cell lines.

B-Lymphocytes↗
PubMed1978

Protein synthesis by rat transplantable yolk sac tumor and its relation to the cytosol levels of translatable messenger RNA's.

alpha-Fetoprotein (AFP) was shown to be the major secretory protein produced in vitro by normal rat yolk sacs. While not so active, AFP production was also detected in the transplantable tumors derived from normal yolk sacs. The major secretory protein synthesized by the tumor cells had a molecular weight of 40,000 and was reactive with an anti-rat albumin antibody. The functional messenger RNA's coding for these proteins were quantitated by translation in a cell-free system derived from wheat germ followed by specific immunoprecipitation of the newly synthesized peptides. The overall template activity of the RNA prepared from the normal yolk sacs and yolk sac tumor cells was virtually identical. The cytosol RNA prepared from the normal yolk sacs was approximately 12 times more active than that from the tumor cells in directing the synthesis of AFP. The presence of the cytosol RNA prepared from the tumor cells was required for the synthesis of proteins immunoprecipitable with the antialbumin antibody. These results suggest that the changes in AFP and albumin synthesis can be accounted for by a corresponding change in the levels of functional messenger RNA's coding for these proteins.

Animals↗
PubMed1978

Susceptibility of human cultured cells to Mason-Pfizer monkey virus.

Mason-Pfizer monkey virus (M-PMV), originally isolated from mammary carcinoma of a rhesus monkey, is infectious to various human cells in tissue culture. Human epithelioid cells (HeLa and HEp-2), fibroblastic cells (embryonic cells as well as virus-transformed embryonic RSb cells), and glial cells (KC) have all been infected with M-PMV. Electron microscope studies have shown that all infected cells produce progeny virus. The titer of infectious M-PMV in cultures of HeLa and HEp-2 cells assayed by KC syncytium formation was 10(1) syncytium-forming unit (SFU) per 0.2 ml. The titers for whole human embryonic cells (HEC), human embryonic lung cells (HEL), and embryonic skin Detroit-551 cells were 10(4) SFU/0.2 ml for each, and 10(3) SFU/0.2 ml for RSb and KC cells.

Animals↗
PubMed1977

Differential effects of heparin on replicative DNA synthesis and unscheduled DNA synthesis.

The effect of heparin on DNA synthesis was compared between replicative DNA synthesis and unscheduled DNA synthesis. Replicative DNA synthesis in permeable cells or nuclei prepared from rapidly growing mouse ascites sarcoma cells was inhibited by heparin. Unscheduled DNA synthesis in nuclei isolated from normal rat liver or from mouse ascites sarcoma cells in stationary phase was stimulated by heparin at low concentrations but inhibited by high heparin concentrations. DNA polymerase activity assayed with activated calf thymus DNA and DNA polymerase alpha purified partially from mouse ascites sarcoma cells was inhibited with either calf thymus histones or heparin. DNA synthesis inhibited with histones was partially reactivated by heparin. Replicative DNA synthesis in permeable cells was inhibited by adding histones to the assay mixture, and the inhibited DNA synthesis was partially reactivated by low concentrations of heparin. These results indicated that the replicated sites (or replication machinery) in permeable cells or nuclei were largely unrestricted by histones and that heparin inhibition of replicative DNA synthesis was due to the direct inhibitory interaction of heparin with some essential component(s), such as DNA polymerase, of replication machinery.

Animals↗
PubMed1977

New phenotypes of serum alpha1-antitrypsin in Japanese detected by gel slab isoelectric focusing.

The phenotype distribution and gene frequencies of serum alpha1-antitrypsin in 856 healthy blood donors in Tokyo were examined by gel slab isoelectric focusing (pH 4--6). The allele of the common subtype variant Pi M2 was present with a frequency of 0.1099 in Japanese. A study of 23 twin pairs and their parents was in agreement with the hypothesis of autosomal codominant inheritance of Pi M subtypes. Other rare variant alleles, Pi MF, Pi MS, Pi MN, Pi mv, Pi MX, Pi MZ were found in very low frequencies. The total concentration of serum alpha1-antitrypsin was compared among three different phenotypic groups (M1, M1M2, M2). Statistically significant quantitative differences were found among these three groups (P less than 0.01).

Alleles↗
PubMed1977

DNA synthesis in detergent-treated mouse ascites sarcoma cells.

Mouse ascites sarcoma cells (SR-C3H/He cells) were made permeable to nucleoside triphosphates by treatment with nonionic detergents in a nearly isotonic condition. The permeable cells synthesized DNA in the presence of the four deoxyribonucleoside triphosphates, ATP, Mg2+, and the proper ionic environment. The optimum detergent concentration for DNA synthesis was 0.015--0.020% with Triton X-100, 0.020% with Nonidet P-40, and about 0.0025% with Brij 58. Higher concentrations of detergents were rather inhibitory to DNA synthesis. DNA synthesis in Triton-permeabilized cells was thought to be replicative, and the activity in the optimum conditions was much higher than that measured in hypotonic permeable cells or in isolated nuclei. These studies show the potential usefulness of detergent treatment for examining DNA replication in mammalian cells in vitro.

Animals↗
PubMed1977

Alkaline phosphatase isoenzyme in intestinal metaplasia of the stomach.

To investigate the relationship of intestinal metaplasia of the stomach and gastric carcinoma, isoenzymatic analysis of alkaline phosphatase (ALP) of the intestinal metaplasia was studied. Purified human intestinal ALP, and anti-human intestinal ALP antibody were used, and mucosa ALP of the other segments of human gastro-intestinal tract was studied simultaneously. Radioimmunoassay technique, and immunofluorescent staining using anti-human intestinal ALP antibody, were applied to the stomach resected for gastric carcinoma or peptic ulcer, ALP extracted from the mucosa of intestinal metaplasia, and from the mucosa of the other segments of human gastro-intestinal tract, was identical with intestinal ALP in its enzymological and immunological properties.

Alkaline Phosphatase↗
PubMed1977

Hepatitis B e antigen and infectivity of hepatitis B virus.

For confirmation of the difference in the infectivity of hepatitis B surface antigen (HBS Ag)-positive serum according to differences in the e antigen system, four chimpanzees were inoculated with serum positive for hepatitis B e antigen (HBe Ag), and three chimpanzees were inoculated with serum positive for antibody to HBe Ag (anti-HBe). Since the infectivity titrations are not yet completed, the end infectivity titer of each serum is not known. All four chimpanzees given injections of 10(-1), 10(-4), or 10(-8) dilutions of HBe Ag-positive serum developed hepatitis B virus infection, whereas the one chimpanzee injected with undiluted anti-HBe-positive serum became infected, and other chimpanzees injected with diluted anti-HBe-positive sera did not. As judged from the length of the incubation period before appearance of HBS Ag in blood, there seemed to be a remarkable difference in infectivity between the HBe Ag-positive serum and the anti-HBe-positive serum; the former serum was 10(8) times more infectious than the latter.

Animals↗
PubMed1977

RNA synthesis in mitochondria isolated from rat liver.

Mitochondrial RNA (mtRNA) was synthesized from purine and pyrimidine nucleosides in coupling with oxidative phosphorylation using isolated mitochondria. The in vivo synthesized mtRNA was adenine-uracil rich and sedimented at about 20 S by sucrose density gradient centrifugation. A major part of the newly synthesized mtRNA was shown to be poly (A)-containing RNA by the resistance to the digestion with pancreatic RNase and RNase T1 and the affinity to poly (U)-Sepharose columns or Millipore filters.

Animals↗
PubMed1977

Studies on human KC cell syncytia formation induced by Mason-Pfizer monkey virus.

Human KC cell monolayer inoculated with concentraten Mason-Pfizer monkey virus (MPMV) showed syncytia formation within an hour. The cell fusion was blocked by the treatment of the MPMV with neutralizing antiserum. Treatment of the MPVM with beta-propiolactone resulted in the loss of infectivity although KC cell fusion ability of the virus still remained. KC cells inoculated with unconcentrated MPMV showed no cell fusion even after several transfers, although a chronic MPMV infection was established. The virus-producing KC cells were refractory to fusion by MPMV. Human embryonic lung cells (HEL) were infected by serially diluted MPMV harvested from virus-producing culture, transferred twice, then cultivated together with KC cells for syncytia formation to examine the end point dilution titer of the virus. HEL infected by 10(-4)-diluted MPMV still induced syncytia formation by cocultivation with KC cells.

Animals↗
PubMed1977

Thermal denaturation and template activities of reconstituted DNA-histone complexes.

Reconstituted complexes of DNA with histone were prepared by salt-and-urea step gradient dialysis. The DNA was complexed with histone H1, with the combination of the other four histones H2A, H2B, H3 and H4, and with whole histones. These DNA-histone complexes were purified by Bio-Gel column chromatography, and the weight ratio of histone-to-DNA was determined in each complex. The thermal denaturation profile and nuclease digestion pattern of DNA-histone H2A, H2B, H3 and H4 complex were compatible with those of the polynucleosome structure of chromatin. The template activities for transcription were compared in these DNA-histone complexes by separately measuring initiation reaction and chain elongation. The binding of histone H1 to DNA strongly inhibited the initiation, while the binding of the combination of the other four histones to DNA partially inhibited the initiation and chain elongation. The binding characteristics are discussed with regard to the role of histone H1 and the other four histones in chromatin structure and template activity.

Animals↗