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Biomedical subjects

S Ohtani

Publications and source records attributed to S Ohtani.

At least 181 records · Page 10Linked to original sources
PubMed1981

Experimental allergic encephalomyelitis induced by basic protein with synthetic adjuvant in comparison with Freund's complete adjuvant. Role of antibodies in correlation with the clinicopathological features.

Experimental allergic encephalomyelitis (EAE) was induced in guinea pigs with bovine myelin basic protein (BP) with adjuvant of either synthetic muramyl dipeptide (Mdp) or Mycobacterium tuberculosis (Tbc). The following results were obtained: (1) The body temperature of the animals was studied serially after sensitization and its elevation was shown to be an early sign of EAE. (2) Several animals developed the clinical and histological signs of hyperacute EAE. (3) An optimal combined dosage of BP and adjuvant was found for induction of clinical EAE and for the the production of complement fixing (CF) antibodies. (4) Little passive hemagglutinating (PH) antibody was produced by single immunization. These results displayed no essential difference in EAE induced by either adjuvant. (5) Detectable PH antibodies developed later in addition to CF antibodies in a few animals immunized with Tbc adjuvant. These animals were skin-tested to BP, and had recovered from body weight loss or limb weakness. The results suggest that humoral antibodies play a role in modifying the disease process, even if they are not essential in production of EAE.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1981

Kinetic properties of bovine pineal tryptophan-5-monooxygenase activated by an endogenous activating substance.

We previously reported that an endogenous activating substance different from bovine serum albumin, phospholipids and heparin, exists in the extract from bovine pineal glands and that this substance interacts with tryptophan-5-monooxygenase under reducing conditions with sulfhydryl reagents, to stimulate monooxygenase activity. The present paper reports that the activating substance is of peptide nature; that it is sensitive to trypsin-digestion; and that it does not change the apparent Km's for substrates, L-tryptophan and oxygen, and coenzyme, reduced biopterin or DMPH4; but that it increases the Vmax 1.5- to 2.3-fold. These results suggest that an activating protein, present in some particles of the cell structure, activates tryptophan-5-monooxygenase under the regulation of a sulfhydryl compound. The apparent Km's for reduced biopterin and DMPH4 were 77.2 microM and 294 microM, respectively. The apparent Km's for L-tryptophan and oxygen with reduced biopterin were 15.0 microM and 4.7%, respectively; with DMPH4, they were 11.0 microM and 8.5%, respectively. Significant inhibition of both L-tryptophan and oxygen was observed with reduced biopterin, but not with DMPH4 (at the tested concentrations of up to 0.5 mM and 20%, respectively).

Animals↗
PubMed1981

Experimental allergic encephalomyelitis (EAE) in two inbred guinea pigs. II. Strain differences in susceptibility to passive transfer of EAE.

Two inbred strains of guinea pigs, Strain 13 and JY-1, were compared with regard to their susceptibility to the elicitation of experimental allergic encephalomyelitis (EAE) by passively transferred sensitized lymph node cells. Recipient guinea pigs were injected with more than 2 X 10(8) of viable lymph node cells from donors that had been immunized for the elicitation of EAE 8 days prior to the cell transfer. 1) Clinical course of EAE in all adult guinea pigs passively transferred with adult and juvenile sensitized lymph node cells was acute. 2) Sensitized cells required for successful passive transfer of EAE was less in JY-1 guinea pigs than in Strain 13 guinea pigs. 3) The sensitized cells from juvenile Strain 13 guinea pigs were less competent to transfer EAE than the adult ones whereas in JY-1 guinea pigs the juvenile cells were as effective as the adult ones.

Age Factors↗
PubMed1980

On the base-stacking in the 5'-terminal cap structure of mRNA: a fluorescence study.

The fluorescence at 370 nm of the 7-methylguanosine residue (m7G) is found to be quenched when the base residue is involved in a stacking interaction with the adenosine residue in the cap structure m7G5' pppA of an eukaryotic mRNA. On the basis of the observed degree of quenching, the amounts of the stacked and unstacked forms in the cap structure have been determined at various temperatures and pH's. It has been found that at pH 6.2 effective enthalpy and entropy in the unstacked leads to stacked change are delta H degrees = 4.4 +/- 0.1 kcal/mole and delta S degrees = - 14.3 +/- 0.2 e.u., respectively. The pka value for the m7G residue is found to be 7.7 at 10 degrees C and 7.3 at 30 degrees C. The stacked structure seems to be less favourable in the deprotonated form that occurs in the higher pH solution. A similar analysis of some other cap structures indicates that the stacked form in m7G5' pppN structure is favourable if N is a purine nucleoside or a 2'-O-methylpyrimidine nucleoside but not for an unmethylated pyrimidine nucleoside.

Adenosine↗
PubMed1980

Experimental allergic encephalomyelitis (EAE) in two inbred guinea pigs: 1. Strain differences in developing chronic relapsing form of EAE.

Two inbred strains of guinea pig (Strain 13 and JY-1) were compared with regard to their reactivity to the central nervous tissue emulsion in complete Freund's adjuvant as the challenge for elicitation of EAE. The susceptibilities to EAE sensitization of adult guinea pigs were almost equal between the two strains, while those of young animals were different. The young Strain 13 guinea pigs are liable to develop chronic relapsing form of EAE, the incidence is 100% in 4--5 weeks guinea pigs and 60% in 6 weeks. On the contrary young JY-1 guinea pigs were as susceptible as adults. They developed typical acute EAE, which was usually fatal. Central nervous system of acute and chronic EAE guinea pigs of two strains was examined by the indirect immunofluorescent technique for the detection of lymphocytes. Most of the positive lymphocytes were detected in the perivascular space and some were detected in the parenchyma of the brain.

Animals↗
PubMed1979

Some characteristics of persistent rabies virus infection in cell cultures.

Fixed rabies virus strain M512 was shown to propagate in BHK cell cultures without interfering with cell growth. Virus specific antigen was detected in the cytoplasm of cells by immunofluorescence technique. A small amount of virus was detected in the supernatant fluid throughout a series of subcultures. The infectivity of the intracellular virus was not affected by the addition of antirabies serum in culture fluid through the extracellular spread of virus was inhibited at the 40th transfer of the infected BHK Cells suggesting the establishment of the persistent M512 infection. Ninety five percent or more cells after cloning from persistently infected cells possessed viral antigen. Based on cytopathic effect, BHK-M512 cells were resistant to superinfection with the homologous virus but were susceptible to the heterologous virus. Interferon was not detected in BHK-M512 cell cultures. The serially passaged BHK-M512 virus gradually decreased the virulence for mice after 40th subculture.

Animals↗
PubMed1978

Ultrastructural localization of rabies virus antigens in infected trigeminal ganglion of hamsters.

The trigeminal ganglion of hamsters infected with CVS strain of rabies virus was investigated by electron microscopy with peroxidase-labeled antibody. Major localization of virus antigens were the following three types of structures; rabies virion, cytoplasmic inclusion, and ribosomal granules consisting of Nissl body. Rabies virions in neurons were mostly found within the cluster of such ribosome-rich regions suggesting a close relationship between the two in the synthesis of virus antigen. The cytoplasmic inclusion appeared to be derived from ribosomal or allied particles with virus-specific antigens. The significance of results obtained is briefly discussed.

Animals↗