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Biomedical subjects

T Oshima

Publications and source records attributed to T Oshima.

At least 505 records · Page 28Linked to original sources
PubMed1984

Interrelationship of eosinophilia and IgE antibody production to larval ES antigen in Toxocara canis infected mice.

In order to elucidate the relationship between eosinophilia and IgE antibody production in parasitic infection, the degree of eosinophilia and IgE antibody levels to larval ES antigen of Toxocara canis were investigated in eight inbred strains of mice after infection with T. canis. Eosinophilia was far higher in degree in SJL mice than in the other inbred strains. However, IgE antibody levels to larval ES antigen in SJL mice were the lowest among those inbred strains. Similarly, the degree of eosinophilia in AKR mice was slightly higher than those in the other strains except SJL mice, but IgE antibody levels to larval ES antigen in AKR mice was as low as that in SJL mice. Consequently, high responders for eosinophilia were not always high responders for IgE antibody production to larval ES antigen. Inheritance of the two traits, marked eosinophilia and poor IgE antibody production to larval ES antigen in T. canis infected SJL mice, were investigated using F1 hybrid and back-cross mice. The former was regulated by more than one gene, while the latter was a recessive trait. The degree of eosinophilia after infection showed no relationship with the total numbers of larvae recovered from T. canis infected inbred mice.

Animals↗
PubMed1984

Mating type control in Saccharomyces cerevisiae: a frameshift mutation at the common DNA sequence, X, of the HML alpha locus.

A mutation defective in the homothallic switching of mating type alleles, designated hml alpha-2, has previously been characterized. The mutation occurred in a cell having the HO MATa HML alpha HMRa genotype, and the mutant culture consisted of ca. 10% a mating type cells, 90% nonmater cells of haploid cell size, and 0.1% sporogenous diploid cells. Genetic analyses revealed that nonmater haploid cells have a defect in the alpha 2 cistron at the MAT locus. This defect was probably caused by transposition of a cassette originating from the hml alpha-2 allele by the process of the homothallic mating type switch. That the MAT locus of the nonmater cells is occupied by a DNA fragment indistinguishable from the Y alpha sequence in electrophoretic mobility was demonstrated by Southern hybridization of the EcoRI-HindIII fragment encoding the MAT locus with a cloned HML alpha gene as the probe. The hml alpha-2 mutation was revealed to be a one-base-pair deletion at the ninth base pair in the X region from the X and Y boundary of the HML locus. This mutation gave rise to a shift in the open reading frame of the alpha 2 cistron. A molecular mechanism for the mating type switch associated with the occurrence of sporogenous diploid cells in the mutant culture is discussed.

Alleles↗
PubMed1984

An atrial peptide is a potent renal vasodilator substance.

Renal intra-arterial administration of rat atrial extracts elicits a concentration dependent renal vasodilation (independent of prostaglandin or dopamine release) in anesthetized rats. The atrial extracts do not alter skeletal musculature (hindlimb) vascular resistance or systemic arterial blood pressure. The high molecular weight peptide fraction of atrial extracts obtained by gel filtration, reduces renal resistance intra-arterially only after proteolytic activation (in vitro) or following intravenous (i.e., systemic in vivo activation) administration. The low molecular weight peptide fraction of the atrial extract which is active intra-arterially as a renal vasodilator has been further purified to yield two major peptides. The 21 amino acid peptide, designated atriopeptin I, was previously demonstrated to be natriuretic and to relax intestinal but not vascular smooth muscle strips. This peptide exerted little or no intra-arterial effect on renal resistance. The 23 amino acid peptide (the phenylalanine-arginine C terminal extension of atriopeptin I), designated atriopeptin II, was natriuretic and spasmolytic (in vitro) on both intestinal and vascular strips and was a potent renal vasodilator in vivo. Thus, the renal vasodilator activity present in cardiac atrial extracts appears to derive from a proteolytic process which selectively generates the 23 amino acid peptide, atriopeptin II. Further cleavage with the loss of phenylalanine-arginine C-terminal, as occurs with atriopeptin I, markedly suppresses the renal vasodilation.

Animals↗
PubMed1984

Pharmacological manipulation of canine cyclooxygenase and thromboxane synthetase in vivo: differential renal and platelet recovery rates.

Aspirin (acetylsalicylic acid) was chronically infused i.v. into dogs at a low dose (0.1 mg/kg/hr) using a surgically implanted Alzet osmotic pump. The time course for inhibition of cyclooxygenase and for its recovery after removal of the pump were followed in washed platelet preparations and in kidney medulla microsomes using [14C]arachidonic acid metabolism. Chronic acetylsalicylic acid infusion inhibited platelet cyclooxygenase 60% after 1 day of treatment and 95% after 3 days. Recovery of platelet arachidonate metabolism after removal of the osmotic pump was very rapid (T 1/2 = 0.9 days). Renal cyclooxygenase was also completely inhibited after 3 days but showed a slower recovery rate (T 1/2 = 2.8 days). Therefore, canine platelets, unlike human platelets, recover more rapidly from acetylsalicylic acid inhibition than do the kidneys. We have also established a whole blood method to study the effective time course of thromboxane synthetase inhibitors. The relative potencies for inhibiting platelet thromboxane synthetase after i.v. bolus administration of the agents studied was OKY-1581 greater than OKY-046 = dazoxiben much greater than Ro 22-7878. The effective half-life of OKY-1581, OKY-046 and dazoxiben was 2 hr while the half-life of Ro 22-7878 was 0.5 hr.

Animals↗
PubMed1984

[Renovascular hypertension with a solitary kidney associated with retrocaval ureter: a case report].

A case of renovascular hypertension in a patient with a congenitally solitary kidney associated with retrocaval ureter is reported. Aortorenal bypass with autogenous saphenous vein graft and concomitant mobilization of the ureter by division and reanastomosis of the inferior vena cava were performed. Pathogenesis of the stenotic lesion of the renal artery was fibromuscular dysplasia. Postoperative improvement of hypertension was not so good as expected. Soon after administration of nifedipine (20mg/day) was started, blood pressure decreased down to 130/80mmHg and had been well controlled. Problems regarding renovascular hypertension with a solitary kidney and surgical treatment of retrocaval ureter are discussed.

Adult↗
PubMed1983

Effects of long-term blockade of angiotensin converting enzyme with captopril on blood pressure and aortic prolyl hydroxylase activity in spontaneously hypertensive rats.

In order to determine if long-term treatment with captopril affects vascular collagen biosynthesis we administered the agent at a dose of 30 or 100 mg/kg/day p.o. for 6 weeks to spontaneously hypertensive rats. At the 6th week of captopril treatment the aorta was excised and the activity of prolyl hydroxylase, the rate-limiting enzyme of collagen biosynthesis, was measured. Vascular enzyme activity was decreased by 7.0% and 34.6% in the low- and high-dose groups, respectively. A single oral administration of captopril, on the other hand, did not decrease the enzyme activity in the aorta. Furthermore, captopril had no direct inhibitory effect on the enzyme activity in vitro. These findings suggest that the decrease in vascular prolyl hydroxylase activity resulted from a sustained decrease in blood pressure.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1983

The nucleotide sequence of the yeast PHO5 gene: a putative precursor of repressible acid phosphatase contains a signal peptide.

The nucleotide sequence of the PHO5 gene of the yeast, Saccharomyces cerevisiae, which encodes repressible acid phosphatase (APase) was determined. Comparison of N-terminal amino acid sequence deduced from the nucleotide sequence with that of the purified repressible APase revealed the existence of a putative signal peptide in the precursor protein. The signal peptide was shown to contain 17 amino acid residues and its structural features were quite similar to those of higher eukaryotic and prokaryotic signal peptides. The nucleotide sequence of 5' and 3' noncoding flanking regions of the PHO5 gene are also discussed.

Acid Phosphatase↗
PubMed1983

Expression in Escherichia coli of chemically synthesized gene for the human immune interferon.

A 454 base pair fragment of double stranded DNA consisting of a gene for a human immune interferon (hIFN-gamma), initiation and termination signals plus appropriate restriction endonuclease sites, was totally synthesized. The synthesis involved preparation of 62 oligodeoxyribonucleotides by rapid, solid phase procedures, and enzymatic ligation of the oligonucleotides. This synthetic gene was expressed in E. coli under the control of the lac UV5 promoter. The product has antiviral activity which was acid labile and completely neutralized by antiserum to hIFN-gamma but not by antiserum to hIFN-alpha or hIFN-beta. Molecular weight of hIFN-gamma produced by E. coli was estimated to be about 32,000 and 17,000 by gel filtration and SDS-polyacrylamide gel electrophoresis respectively.

Amino Acid Sequence↗
PubMed1983

Separation and comparison of 2-thioribothymidine-containing transfer ribonucleic acid and the ribothymidine-containing counterpart from cells of Thermus thermophilus HB 8.

For the extreme thermophile Thermus thermophilus HB 8, a positive correlation was observed among the growth temperatures of the cells, the melting temperature, and the 2-thioribothymidine (s2T) content of tRNA extracted from cells grown at various temperatures [Watanabe, K., Shinma, M., Oshima, T., & Nishimura, S. (1976) Biochem. Biophys. Res. Commun. 72, 1137-1144]. On the basis of these observations, studies were carried out from which the following results were obtained. (1) Both RNase T1 and U2 digestions of tRNA gave only four fragments containing s2T or T: s2T psi CGp, s2T psi CAp, T psi CGp, and T psi CAp. For the different growth temperatures, the ratio of the content of s2T psi CGp plus s2T psi CAp to that of T psi CGp plus T psi CAp was almost the same as that of the s2Tp to Tp content reported previously. (2) The midpoint of the s2T-specific circular dichroism spectral change induced by heat was constant for all tRNAs extracted from cells grown at various temperatures, suggesting that the s2T-containing tRNAs melt at about the same temperature, which is independent of the growth temperature of cells. (3) s2T-containing tRNA was separated from the T-containing counterpart quantitatively by a specific modification of s2T with bromoaceto-2,4-dinitroanilide followed by BD-cellulose column chromatography. The molar ratio of the s2T- and T-containing tRNAs was also similar to that of s2Tp to Tp as mentioned above. These results demonstrate that T. thermophilus cells have both s2T- and T-containing tRNAs, whose relative content is controlled by the growth temperature. This phenomenon may be necessary to enable the thermophile to adapt to higher temperatures.

RNA, Transfer↗
PubMed1983

Trapping of large numbers of larvae in the livers of Toxocara canis-reinfected mice.

Congenitally athymic nude mice (BALB/c-nu/nu) and BALB/c-nu/+ were infected with 500 embryonated Toxocara canis eggs. Six weeks later they were reinfected with the same number of eggs. The liver and other organs were examined for numbers of 2nd-stage larvae at 2, 4, and 6 weeks after reinfection. Far more larvae were trapped in the liver after reinfection than after the primary infection but fewer were found in the livers of BALB/c-nu/nu than in BALB/c-nu/+ mice.

Animals↗
PubMed1983

Homocaldopentamine: a new naturally occurring pentaamine.

A new pentaamine was extracted from an extreme thermophile, Thermus thermophilus strain HB8, and its chemical structure was determined to be 1,16-diamino-4,8,12-triazahexadecane (see structure 1). A trivial name, homocaldopentamine, was proposed for the new naturally occurring polyamine.

Polyamines↗
PubMed1983

Activation of complement in C-reactive protein positive sera by phosphorylcholine-bearing component isolated from parasite extract.

Phosphorylcholine-bearing component levels in extracts of various parasites were determined by a capillary precipitin test using anti-phosphorylcholine Ig A myeloma protein. TEPC-15. Phosphorylcholine was demonstrated as a structural component not only in nematodes but also in trematodes and cestodes. The phosphorylcholine-bearing component was isolated from an extract of Toxocara canis larvae using a TEPC-15-Sepharose 4B column. The component reacted with C-reactive protein in sera to form one precipitin line in immunoelectrophoresis. The component provided two Brilliant Coomassie Blue positive bands in SDS-polyacrylamide gel electrophoresis. It reacted with C-reactive protein to activate complement in serum.

Animals↗
PubMed1983

Heterogeneity in mucolipidosis II (I-cell disease).

Normalization of multiple deficiency of intracellular lysosomal hydrolases in I-cell disease (ICD) fibroblasts by sucrose loading has been reported (Kato et al. (1982) J. Biol. Chem. 257, 7814). Further studies revealed that the effects of sucrose on the induction of hydrolases in seven ICD strains examined in this study were characteristic in each strain. The results may indicate that ICD strains can be classified into subgroups by the degree of enzymic induction. Moreover, this speculation seems to be supported by the normalization of electrophoretic patterns of beta-hexosaminidase in ICD fibroblasts after sucrose loading.

Ammonium Chloride↗