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Biomedical subjects

H Kodama

Publications and source records attributed to H Kodama.

At least 433 records · Page 24Linked to original sources
PubMed1990

Isolation and characterization of rainbow trout C-reactive protein.

An acute phase serum component, C-reactive protein (CRP), was isolated from the sera of rainbow trout (Salmo gairdneri). The isolation was based on its calcium-dependent binding affinity for pneumococcal C-polysaccharide (CPS) according to the isolation procedure of human C-reactive protein. In SDS-PAGE, the nonreduced CRP showed two subunits with molecular weights of 43,700 and 26,600, respectively, at a molar ratio of 1:1. The reduced CRP showed a single subunit of 26,600. The molecular weight of the native protein was estimated as 66,000 by native gradient PAGE and 81,400 by sedimentation equilibrium analysis using ultracentrifugation. The antigenic determinant on CPS-reactive site was destroyed by periodate oxidation, indicating that rainbow trout CRP is a glycoprotein. CRP levels in rainbow trout serum measured by the CPS-ELISA procedure showed that the rainbow trout CRP could behave as an acute phase reactant, following experimental infection with the fish pathogen Vibrio anguillarum.

Amino Acids↗
PubMed1990

Characterization of fibroblast-derived prolidase. The presence of two forms of prolidase.

Crude enzyme solutions of prolidase were extracted from cultured human skin fibroblasts derived from control and prolidase-deficient sisters. Two forms of prolidases (prolidase-I and II) were partially purified by high performance liquid chromatography equipped with an ion exchange column. On gel filtration, the relative molecular weights of prolidase-I and II were estimated to be MW = 105,000 and 151,000, respectively. The substrate specificity of partially purified prolidase-I and II in control fibroblasts was estimated against Gly-Pro, Ala-Pro, Met-Pro. Each form of prolidase differed in its substrate specificity. In prolidase-deficient sisters, the elder with typical clinical manifestations and the younger with only slight clinical manifestations, the activity of prolidase-I was absent. However, the activity of prolidase-II was sufficiently present in both sisters. The substrate specificity of prolidase-II in the patients was similar to that of control. No difference in substrate specificity was found between these two patients.

Adolescent↗
PubMed1990

Evaluation of pathogenicity and protective efficacy of serotype 2 Marek's disease virus from birds belonging to genus Gallus in Japan.

The new cloned serotype 2 Marek's disease viruses (MDV) of ML-6, ML-9, and ML-22 strains were inoculated in specific-pathogen-free (SPF) chicks to evaluate the pathogenicity and protective efficacy. Chicks inoculated or contact-infected with ML strains showed no gross and histological lesions in lymphoid organs, sciatic plexuses and other visceral organs during 10 weeks of observation periods, indicating that the viruses were non-pathogenic. Moreover, the viruses were found to be spread horizontally among chicks by demonstrating the presence of viremia in contacted chicks at 2 weeks-old. Chicks vaccinated with ML-6 at one day-old were protected against subsequent challenge by inoculation with virulent MDV strain of Md/5 at 4 or 7 days old or by contact infection at 7 days old with chickens previously inoculated with the same strain.

Animals↗
PubMed1990

Immunosuppressive effect of infectious pancreatic necrosis virus on rainbow trout (Oncorhynchus mykiss).

The infectivity of infectious pancreatic necrosis virus (IPNV) for rainbow trout (Oncorhynchus mykiss) mononuclear leukocyte subpopulations was investigated to determine the mechanisms of immunosuppression caused by the virus. IPNV was recovered from nylon wool-adherent, surface immunoglobulin (Ig)-positive leukocytes of head kidney, spleen and peripheral blood collected from virus-inoculated fish with higher titers than non-adherent, Ig-negative cells. Non-adherent cell population showed mitogenic response to phytohemagglutinin and concanavalin A but not to lipopolysaccharide. Conversely, the responses of adherent cells to these mitogens were weak. Mitogenic response and non-specific cytotoxicity of head kidney leukocytes significantly decreased by the inoculation of fish with the virus. These results suggest that the suppression of immune responses is involved in the establishment of carrier state in fish after infection with IPNV.

Animals↗
PubMed1990

Production and characterization of monoclonal antibodies against chicken lymphocyte surface antigens.

A panel of monoclonal antibodies (mAbs) with specificity for chicken lymphocyte surface antigens was established and characterized based on their reactivities against chicken lymphoid cells and tumor cell lines on flow cytometry. Three mAbs (7-3G-2, 7-2E-8, and JB-2) reacted preferentially with thymocytes, however, none of them reacted with Marek's disease derived T lymphoblastoid cell lines. Four mAbs (6-27A-1, 4-5C-5, Lc-4, and Lc-6) reacted with spleen cells and peripheral blood leukocytes as well as thymocytes. All seven mAbs reacted with chicken embryonic thymocytes from day 12 of embryonic life onward. All mAbs showed no reactivity against bursal lymphocytes.

Animals↗
PubMed1990

Identification of virus-specific antigens in cultured cells infected with Marek's disease virus serotype 2 and CVI-988 strain.

For the identification of serotype-specific antigens of Marek's disease virus (MDV) serotype 1 (MDV1) or serotype 2 (MDV2), a total of 24 hybridoma clones, secreting monoclonal antibodies (MAbs) against CVI-988 (MDV1) or HPRS-24 (MDV2) strain, were established and characterized by immunofluorescence assay, virus neutralization and immunoprecipitation analysis. Based upon the molecular weights (mol. wt.) of the immunoprecipitated polypeptides, the MAbs were subdivided into 7 groups. Among them, two groups of MAbs reacted with antigens that have not been reported, were identified. MAbs belonging to the first group reacted with CVI-988- and MDV2-specific antigens with mol. wt. ranging from 29 K to 34 K (29/34 K). This antigen was not found in cells infected with Md/5 and JM strains of MDV1, and the results of kinetic analysis of antigen expression showed this antigen appeared to be related to late membrane antigens. MAbs belonging to the second group immunoprecipitated MDV2-specific antigens with mol. wt. of 37 K, 33 K and 31 K from HPRS-24-infected cells or with those of 37 K, 34 K and 31 K from SB-1(MDV2)-infected cells, and these antigens appeared to be related to early antigens. MAbs belonging to the other 5 groups included those which recognized similar antigens reported previously or the antigens characterized insufficiently in this study.

Animals↗
PubMed1990

Conformation and properties of hammerhead-type RNA enzymes.

We designed a hammerhead-type RNA enzyme system which consists of three ribooligonucleotide strands (1-3), synthesized these oligomers and their analogues, and examined conformation and properties of the RNA complexes. Imino proton NMR spectra of the complexes were measured and the signals were assigned by comparison with the spectra of some model duplexes. Examination of a complex containing a G----I mutation (Y = I) revealed that the 2-amino group of the third guanosine residue in the loop 1 (L1) plays an important role for maintaining both the activity and loop conformation.

Base Sequence↗
PubMed1990

[A case of thoracoabdominal aortic aneurysm ruptured into the right extrapleural cavity].

A 63-year-old man of thoracoabdominal aortic aneurysm was transferred to our department. Thoracic and abdominal enhanced CT scan revealed a Crawford's type I A thoracoabdominal aortic aneurysm ruptured into the right extrapleural and retroperitoneal spaces. Without any more additional examination, graft replacement and reconstruction of a lower intercostal artery were performed with an aid of femoro-femoral bypass. Although the postoperative course was complicated by hypertension, hypoventilation and liver dysfunction, the patient recovered from the operation and 10 months later he is leading an almost normal life. Since emergency operation of thoracoabdominal aneurysm is the most courageous challenge because of the difficulties of exposure and visceral organ protection against ischemic, there have been only nine cases with successful surgery in Japan. Now we actively reconstruct lower intercostal and lumbar arteries to prevent spinal cord ischemia without ESCP monitoring in emergency cases.

Aorta, Abdominal↗
PubMed1990

Characterization of two monoclonal antibodies which recognize different subpopulations of chicken T lymphocytes.

Distribution among peripheral T lymphocyte subpopulations and biochemical properties of the chicken lymphocyte surface antigens defined by monoclonal antibodies (mAbs) Lc-4 and Lc-6 were examined. Two-color immunofluorescence analysis revealed that Lc-4 and Lc-6 antigens were expressed on mutually exclusive subpopulations of peripheral T lymphocytes but not on B lymphocytes. Lc-4 mAb precipitated a polypeptide with apparent molecular mass of 35 and 65 kilodalton under reducing and non-reducing conditions, respectively. These results indicated that the antigen recognized with Lc-4 was closely similar in tissue distribution and biochemical property to mammalian CD8 antigen.

Animals↗
PubMed1989

Enzyme inhibition by dipeptides containing 2,3-methanophenylalanine, a sterically constrained amino acid.

Both isomers of (E)-2,3-methanophenylalanine (delta EPhe), a sterically restricted amino acid, were incorporated into peptides in order to examine their possible enzyme inhibitory activity. Both (2R,3S)- and (2S,3R)- delta EPhe-Phe(or Leu)-OMe were found to inhibit effectively the hydrolysis of Ac-Tyr-OEt by chymotrypsin in a competitive manner. The ester groups of these dipeptides were quite resistant to chymotrypsin hydrolysis, and the delta EPhe-Phe peptide bond was also entirely stable. The inhibition constant (Ki) of the most potent dipeptide of H-(2R,3S)-delta EPhe-Phe-OMe was 0.16 mM at 25 degrees C. The inhibitory action of delta Phe-containing peptides was found to depend on the configuration of the delta Phe residue. The electrophilic nature of the cyclopropane ring which is conjugated with both the phenyl ring and the ester carbonyl group appears to be relevant to the inhibitory activity. Fully irreversible inactivation of chymotrypsin was achieved by its incubation with H-(2R,3S)- delta EPhe-Leu-OMe. An enzyme carboxylate group is thought to be responsible for nucleophilic attack on the cyclopropane ring leading to irreversible inactivation.

Chemical Phenomena↗
PubMed1989

Interleukin 7 production and function in stromal cell-dependent B cell development.

The role of IL-7 in the stromal cell-dependent B cell development was investigated using two stromal cell clones, ST2 and PA6; the former supports B lymphopoiesis while the latter can not. We demonstrate here that: (a) the ability of the stromal cell clone to produce IL-7 correlates well with the stromal cell activity to support B lymphopoiesis; (b) IL-7 production by ST2 is inducible rather than constitutive; (c) the IL-7-dependent B cell itself is a potent inducer of IL-7 production by ST2; (d) addition of rIL-7 to the PA6 layer renders this in vitro environment B lymphopoietic; and (e) the differentiation from early B progenitor to pre-B cell requires both IL-7 and other stromal cell molecule(s) yet to be identified.

Animals↗
PubMed1989

Dimeric substance P analogue shows a highly potent activity of the in vivo salivary secretion in the rat.

We have synthesized a dimeric analogue of substance P (SP) COOH-terminal nonapeptide fragment (D-SP-(3-11] and examined the in vivo and in vitro biological activities in the submaxillary gland of the rat. The dimer elicited an enhanced biological response as compared with receptor binding, showing 2.4-fold more potent receptor affinity than its monomer and 75-fold more potent in vivo salivary secretion activity.

Animals↗
PubMed1989

Binding characteristics of a series of dimeric tripeptide enkephalins for delta opiate receptors in rat brain and NG108-15 cells.

The N-terminal tripeptide enkephalin analogue, Tyr-D-Ala-Gly, was dimerized at the C-terminus systematically with a series of alpha,omega-diaminoalkanes, NH2-(CH2)n-NH2 (n = 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, and 22). The binding affinities of dimers for delta opiate receptors in rat brain were evaluated and compared with those for delta receptors in NG108-15 cells. Although the monomeric tripeptide amide was almost inactive, dimers showed a dramatic increase in binding affinity (8-900 times). The enhancement of affinity was apparently related to the number of methylene chains in the crosslinking spacer moiety, and it was maximal at n = 14-18 in the rat brain. In NG cells the activity increased progressively from n = 2 to n = 22 without reaching any apparent peak. These results suggest that delta receptors in rat brain and NG cells may have slight structural differences.

Animals↗
PubMed1989

Serological and genetical relationships of three herpesvirus strains from salmonid fish.

Serological and genetical relationships of three salmonid herpesviruses [strain H-83, OO-7812 strain of Oncorhynchus masou virus (OMV) and Herpesvirus salmonis] were investigated. Although the serological relationships of these viruses were not distinctly demonstrated by cross-neutralization test, cross enzyme-linked immunosorbent assay revealed that strain H-83 and OMV appeared to be serologically more closely related to each other than to H. salmonis. Strain H-83 was genetically similar to OMV but distinct from H. salmonis by restriction endonuclease cleavage analysis and DNA-DNA hybridization test. These results indicated that strain H-83 should be classified under the same group as OMV, and H. salmonis belong to another group of salmonid herpesviruses.

Animals↗