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Biomedical subjects

S Ohno

Publications and source records attributed to S Ohno.

At least 631 records · Page 35Linked to original sources
PubMed1992

Ultrastructural study of the glomerular slit diaphragm in fresh unfixed kidneys by a quick-freezing method.

In normal kidneys fixed by perfusion with tannic acid and glutaraldehyde, glomerular slit diaphragms have been reported to consist of highly ordered and isoporous substructures with a zipper-like configuration. We have re-evaluated the ultrastructure of fixed or unfixed glomeruli using quick-freezing and deep-etching (QF-DE) and freeze-substitution (QF-FS) methods. In the fixed slit diaphragms, zipper-like substructures were often observed by the QF-DE method. In contrast, in fresh unfixed glomeruli the slit diaphragms mainly consisted of non-porous substructures. The slit diaphragms were more widely opened in the fixed glomeruli, as examined by the QF-FS method. These results suggest that the foot processes shrink during tissue preparation by conventional methods with chemical fixatives, and that the broadening of slit diaphragms and zipper-like substructures are formed by the pulling apart of adjacent foot processes due to shrinkage.

Animals↗
PubMed1992

Three-dimensional study of epithelioid cells by a quick-freezing and deep-etching method in muramyl dipeptide-induced granulomas.

The three-dimensional ultrastructure of epithelioid cells was studied by the quick-freezing and deep-etching (QF-DE), as well as the freeze-substitution (QF-FS) methods. The granulomas were induced in rats by injecting muramyl dipeptide (MDP) into the hind footpads. At 3 weeks after the injection, the footpads were perfused with a fixative, excised, and quickly frozen to prepare the replica membranes. Some unfixed footpads were also quickly frozen and freeze-substituted. Dense networks of intermediate filaments, connected with the nuclei, mitochondria and other vesicular cell organelles, were observed throughout the cytoplasm of epithelioid cells by the QF-DE method. A few actin filaments were located in filopodia and just beneath the cell membranes. Interdigitation of the cell membranes between adjacent cells was clearly demonstrated by the QF-FS method and clathrin-coated pits were identified at the base of interdigitating filopodia. In addition, the exact moment of fusion between endosomes and lysosomes was ascertained by the same method. These results suggest that the cytoskeletal organization of epithelioid cells resembles that of epithelial cells rather than actively motile macrophages.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1992

Ontogeny of testicular steroid dehydrogenase enzymes in pig (3 alpha/beta-, 20 alpha- and 20 beta-): evidence for two forms of 3 alpha/beta-hydroxysteroid dehydrogenase.

Three enzymatic activities (3 alpha/beta-hydroxysteroid dehydrogenase, 20 beta- and 20 alpha-hydroxysteroid dehydrogenases) were measured in testes of pigs as a function of age. Earlier studies reported a highly purified 20 beta-hydroxysteroid dehydrogenase from neonatal pig testes that also showed strong 3 alpha/beta-hydroxysteroid dehydrogenase activity [Ohno et al., J. Steroid Biochem. Molec. Biol. 38 (1991) 787-794]. We report here that neonatal pigs testis is rich in 3 alpha/beta- and 20 beta-hydroxysteroid dehydrogenase activities, both of which fall to low levels (measured as specific activity) at 60 days. Thereafter the activity of 3 alpha/beta-reduction rises to high levels whereas 20 beta-reduction remains low. Activity of 20 alpha-reduction is of intermediate level in the neonate, falls to a nadir at 60 days and rises to high levels in the mature animal. Western blots of cytosolic proteins show that the bifunctional enzyme (3 alpha/beta-plus 20 beta-hydroxysteroid dehydrogenase) is high in neonatal testes and falls to low levels at maturity. It is proposed that the neonatal testis possesses the bifunctional enzyme which is replaced by a second enzyme at maturity, that is a 3 alpha/beta-hydroxysteroid dehydrogenase without 20 beta-reductase activity. The possible functional significance of these changes is considered.

20-Hydroxysteroid Dehydrogenases↗
PubMed1992

3 alpha-hydroxysteroid dehydrogenase activity catalyzed by purified pig adrenal 20 alpha-hydroxysteroid dehydrogenase.

In earlier studies, two distinct molecules, 20 alpha-HSD-I and 20 alpha-HSD-II, responsible for 20 alpha-HSD activity of pig adrenal cytosol were purified to homogeneity and characterized [S. Nakajin et al., J. Steroid Biochem. 33 (1989) 1181-1189]. We report here that the purified 20 alpha-HSD-I, which mainly catalyzes the reduction of 17 alpha-hydroxyprogesterone to 17 alpha,20 alpha-dihydroxy-4-pregnen-3-one, catalyzes 3 alpha-hydroxysteroid oxidoreductase activity for 5 alpha (or 5 beta)-androstanes (C19), 5 alpha (or 5 beta)-pregnanes (C21) in the presence of NADPH as the preferred cofactor. The purified enzyme has a preference for the 5 alpha (or 5 beta)-androstane substrates rather than 5 alpha (or 5 beta)-pregnane substrates, and the 5 beta-isomers rather than 5 alpha-isomers, respectively. Kinetic constants in the reduction for 5 alpha-androstanedione (Km; 3.3 microM, Vmax; 69.7 nmol/min/mg) and 5 beta-androstanedione (Km; 7.7 microM, Vmax; 135.7 nmol/min/mg) were demonstrated for comparison with those for 17 alpha-hydroxyprogesterone (Km; 26.2 microM, Vmax; 1.3 nmol/min/mg) which is a substrate for 20 alpha-HSD activity. Regarding oxidation, the apparent Km and Vmax values for 3 alpha-hydroxy-5 alpha-androstan-17-one were 1.7 microM and 43.2 nmol/min/mg, and 1.2 microM and 32.1 nmol/min/mg for 3 alpha-hydroxy-5 beta-androstan-17-one, respectively. 20 alpha-HSD activity in the reduction of 17 alpha-hydroxyprogesterone catalyzed by the purified enzyme was inhibited competitively by addition of 5 alpha-DHT with a Ki value of 2.0 microM. Furthermore, 17 alpha-hydroxyprogesterone inhibited competitively 3 alpha-HSD activity with a Ki value of 150 microM.

20-Hydroxysteroid Dehydrogenases↗
PubMed1992

Antibody response to oral streptococci in Behçet's disease.

The serum antibody titers against oral streptococci were studied by enzyme-linked immunosorbent assay (ELISA) both in patients with Behçet's disease (BD) and control groups. The patients with BD showed significantly higher antibody titers to S. sanguis strains 113-20, 114-23, and 118-1 which were isolated from patients with BD, in comparison with control groups. Also, the reactions of high-titered sera to the crude cell wall and soluble (or membrane) fractions of the 113-20 strain were observed by western blot test. The sera of the patients with BD demonstrated strong bands of approximately 36 kDa, 82 kDa, and 87 kDa in the crude cell wall fractions, and many bands of 80 kDa to 150 kDa in the membrane fractions, indicating that these proteins are the ones leading the high antibody titers to this bacterium in the sera of patients with BD.

Antibodies, Bacterial↗
PubMed1992

Association of HLA-B51 and lack of association of class II alleles with Behçet's disease.

Eighty-one Behcet's disease patients have been studied for HLA association by HLA-DRB1, -DQA1, -DQB1 and -DPB1 genotyping with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique and for NcoI RFLP in the tumor-necrosis factor (TNF beta) gene by Southern hybridization in addition to serological typing. In serological typing, the frequency of HLA-B51 was significantly increased in the patients. In PCR genotyping, there was a significant increase in the HLA-DRB1*0802, DQA1*0301 and DQB1*0303 alleles, whereas the frequencies of DRB1*1502, DQA1*0103, DQA1*0101, DQB1*0601 and DQB1*0501 showed a significant decrease in the patients. No significant difference was observed in any HLA-DPB1 alleles. Among them, B51 was found to be a genetic marker most strongly associated with Behcet's disease (p less than 0.00005, chi 2 = 46.47, pc[corrected p] less than 0.005). The positive and negative associations of class II alleles with the disease can be explained by linkage disequilibrium with B51, and do not reach statistical significance by the corrected p-value test. In NcoI RFLP typing in the TNF beta gene, 250 kb centromeric of the HLA-B gene, the frequency of a 5.5 kb fragment was considerably decreased in the patients when compared to the controls, although the decrease was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1992

A new member of the protein kinase C family, nPKC theta, predominantly expressed in skeletal muscle.

A new protein kinase C (PKC)-related cDNA with unique tissue distribution has been isolated and characterized. This cDNA encodes a protein, nPKC theta, which consists of 707 amino acid residues and showed the highest sequence similarity to nPKC delta (67.0% in total). nPKC theta has a zinc-finger-like cysteine-rich sequence (C1 region) and a protein kinase domain sequence (C3 region), both of which are common in all PKC family members. However, nPKC theta lacks a putative Ca2+ binding region (C2 region) that is seen only in the conventional PKC subfamily (cPKC alpha, -beta I, -beta II, and -gamma) but not in the novel PKC subfamily (nPKC delta, -epsilon, -zeta, and -eta). Northern (RNA) blot analyses revealed that the mRNA for nPKC theta is expressed predominantly in skeletal muscle. Furthermore, nPKC theta mRNA is the most abundantly expressed PKC isoform in skeletal muscle among the nine PKC family members. nPKC theta expressed in COS1 cells serves as a phorbol ester receptor. By the use of an antipeptide antibody specific to the D2-D3 region of the nPKC theta sequence, nPKC theta was recognized as a 79-kDa protein upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis in mouse skeletal muscle extract and also in an extract from COS1 cells transfected with an nPKC theta cDNA expression plasmid. Autophosphorylation of immunoprecipitated nPKC theta was observed; it was enhanced by phosphatidylserine and 12-O-tetradecanoylphorbol-13-acetate but attenuated by the addition of Ca2+. These results clearly demonstrate that nPKC theta should be considered a member of the PKC family of proteins that play crucial roles in the signal transduction pathway.

Amino Acid Sequence↗
PubMed1992

Hyperthermo-radiosensitivity of esophageal cancer cells with high DNA ploidy in vitro.

The in vitro sensitivity to hyperthermia and radiation of esophageal cancer cells obtained from 50 patients was assayed by using the in vitro succinate dehydrogenase inhibition test, and the findings were correlated with data on DNA analysis. The DNA distribution patterns were grouped into types I, II, III and IV, according to the frequency of aneuploid cell populations. Esophageal cancer cells of high ploidy (type IV) had a lower sensitivity to radiation, however, a greater sensitivity to hyperthermia as compared to cells of low ploidy (type II). The sensitivity to hyperthermia was determined as positive in 2 of 8 for type II, in 7 of 25 for type III, and in 9 of 17 for type IV. In contrast, the positive sensitivity rates to radiation in type II, III, and IV were 25.0, 8.0, and 5.9%, respectively. When cells were exposed to combination of radiation with hyperthermia, the positive sensitivity rates increased in all groups (50.0, 44.0 and 70.6% in type II, III, and IV, respectively). There was a significant correlation between mean DNA values and the SD activities following exposure to heat treatment or radiation. These data, describing that cancer cells of high ploidy might have greater sensitivity to hyperthermia compared to radiation, indicate the clinical benefits of hyperthermia in cases of esophageal carcinoma, especially for patients with high DNA ploidy.

Adult↗
PubMed1992

Immune deposits in the glomerular extracellular matrix detected by the quick-freezing and deep-etching method.

Chronic serum sickness nephritis was induced in rats by sensitization with egg albumin. The glomeruli were then examined by the quick-freezing and deep-etching method with immunohistochemical identification of immune complex deposits on replica membranes. In control rats, the glomerular basement membrane showed a three-layered structure. The middle layer was composed of a compact meshwork of fine fibrils that was connected to adjacent endothelial and epithelial cells by perpendicular fibrils in the inner and outer layers. The mesangial matrix contained a similar but looser meshwork structure. In the nephritic rats, small granular deposits were observed within the meshwork, distorting its fine structure. Larger nodular aggregates extended continuously from the middle layer to the epithelial side. Disruption of the connecting fibrils overlying these larger aggregates was noted. The deposits were stained by antiegg albumin or antirat IgG antibodies. Gold particles immunostaining for the sensitizing antigen were also localized within the deposits. These findings suggest that the deposition of immune complexes occurs in the fibrillary meshworks of the mesangium and lamina densa in this experimental model, with the resultant distortion of their meshwork structures and the formation of nodular aggregates.

Animals↗
PubMed1992

Antigen presentation by Toxoplasma-infected cells: antigen entry through cell membrane fusion.

The antigen presentation of cells infected by Toxoplasma gondii (T.g.) for MHC class-I-restricted cytotoxic T cells (CTL) was blocked by treating the T.g.-infected cells with the fungal antibiotic brefeldin A. Electron microscopic analysis of T.g.-infected murine and human-antigen-presenting cells (APC) prepared by the combination of quick-freezing with the deep-etching or freeze-substitution methods revealed that the outer membrane of T.g. fused with some parts of the vacuolar membranes of APC to build up channel-like structures. Work station and cytofluorometry studies detected 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF) in cells infected by BCECF-labeled T.g., which strongly suggested the direct entry into cells of BCECF derived from T.g. These findings provide evidence that T.g. antigens enter the cytoplasm of APC through cell membrane fusion of T.g. and T.g.-infected APC, and that T.g.-infected APC present T.g. antigen for MHC class-I-restricted CTL through the endogenous pathway of antigen presentation.

Animals↗
PubMed1992

Requirements of follicle structure for thyroid hormone synthesis; cytoskeletons and iodine metabolism in polarized monolayer cells on collagen gel and in double layered, follicle-forming cells.

Thyroid cells take up iodine and synthesize thyroid hormones. Thyroid cell polarity plays an important role in the uptake of iodine. However, we do not know whether polarity itself is enough for thyroid hormone synthesis or whether follicle structure is required for it. Using polarized monolayer porcine thyroid cells, cultured on collagen-coated filters, and double layered, follicle-forming cells, we analyzed the relationships of iodine metabolism and cell polarity (and follicle formation). We demonstrated that follicle structure was required for thyroid hormone synthesis. A quick-freezing and deep-etching method revealed the three-dimensional ultrastructures of cytoskeletons in the thyroid cells. On the collagen gel, the thyroid cells are reorganized into polarized monolayer cells; the basal cell membranes are in contact with the collagen gel and the apical ones face the culture medium. Actin microfilaments predominate under the apical cell membranes and intermediate filaments in the basal cytoplasm. The arrangement of these cytoskeletons determines the polarity of the cells. When the cells are cultured as double layers, follicle structures are reconstructed between the two monolayers. When apical cell membranes are in contact with other apical ones or when the cells are cultured as double layers, the cells are reorganized into follicles; the basal cell membranes are in contact with the collagen gel, and the apical ones face the follicle cavities. Actin microfilaments predominate at the apical cell membranes and intermediate filaments in the basal cytoplasm. Polarized thyroid cells transport iodine from the basal compartments to the apical ones, but cannot organify iodine into thyroid hormones. However, follicle-forming cells, cultured as double layers, take up iodine and organify it into thyroid hormones. Polarity is important for iodine uptake, and follicle structure is required for thyroid hormone synthesis.

Animals↗
PubMed1992

A Ca(2+)-independent protein kinase C, nPKC eta: its structure, distribution and possible function.

Protein kinase C consists of a protein family which can be classified into two major groups: Ca(2+)-dependent conventional protein kinase C and Ca(2+)-independent novel protein kinase C (nPKC). Among eight known members of protein kinase C family, we found that nPKC eta (eta) isolated from cDNA library of mouse skin, is most abundant in epithelial tissues including skin and epithelia of digestive and respiratory tracts. These data suggest potential role of this isoform in growth, differentiation and carcinogenesis of epithelial tissues.

Animals↗
PubMed1992

Pericholangitis with ulcerative colitis following autoimmune hepatitis over 12 years.

A 35-year-old woman was diagnosed as autoimmune hepatitis 12 years ago by abnormal findings of liver tests including lupus erythematosus (LE) cell phenomenon and liver biopsy. She was admitted in May 1990 with a history of lower gastrointestinal bleeding. Colonoscopy with biopsy and barium enema revealed chronic ulcerative colitis along the entire colon. Since liver tests did not respond well to prednisolone treatment, liver biopsy was again performed and it revealed periductal inflammation with small duct proliferation, a finding compatible with pericholangitis. We herein report this patient who was initially diagnosed as autoimmune hepatitis and thereafter found to be pericholangitis associated with ulcerative colitis.

Adult↗
PubMed1992

Human leukocyte antigen serologic and DNA typing of Behçet's disease and its primary association with B51.

Ninety Japanese patients with Behçet's disease (BD) were typed for human leukocyte antigen (HLA)-DRB1, -DQA1-, -DQB1, and -DPB1 alleles by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and for HLA-A, -B, -C, -DR, and -DQ antigens by conventional serologic typing. Serologic HLA typing showed a remarkably significant increase of HLA-B51 and a significant decrease of HLA-DQw1 in the patients with BD, especially those with ocular lesions including complete type, as compared with the control group (for B51, chi-squared = 46.75, P corrected < 0.001, relative risk [RR] = 7.9; for DQw1, chi-squared = 12.10, P corrected < 0.01, RR = 0.4). By PCR-RFLP genotyping, no significant difference was revealed in any class II alleles between the patient and the control groups in the corrected P value test, but P value analysis showed the significantly high frequency of DRB1*0802 and the significantly low frequencies of DQA1*0103, DQB1*0601, and DQB1*0501. No significant difference was observed in any DPB1 alleles by either P value analysis. These results indicated that the primary and primordial gene(s) responsible for the susceptibility to BD, especially related to ocular lesions, were not located in the HLA class II gene region but were in or very close to the HLA-B locus in the class I region. They also suggested the possibility that BD was a symptom complex associated with some independent diseases.

Alleles↗
PubMed1992

Role of protein kinase C in the modulation of multidrug resistance: expression of the atypical gamma isoform of protein kinase C does not confer increased resistance to doxorubicin.

Cross-resistance to anticancer drugs, termed multidrug resistance (MDR), is functionally associated with the expression of a plasma membrane, energy-dependent, drug efflux pump termed P-glycoprotein (PGP), the product of the mdr1 gene. We have shown previously that MCF-7 breast carcinoma cells transfected with the human mdr1 gene (BC-19 cells) exhibit greater MDR when stably transfected with protein kinase C alpha (PKC alpha). We now demonstrate that transfection of BC-19 cells with the gamma isoform of PKC (BC-19/PKC gamma cells), which is not normally present in BC-19 cells, does not confer increased resistance to doxorubicin, despite a 19-fold increase in PKC activity. All of the increased PKC activity is accounted for by PKC gamma and it is rapidly down-regulated by phorbol dibutyrate, within 15 min of treatment. Endogenous PKC alpha and PKC epsilon activities are not affected by phorbol dibutyrate. The cytotoxicity of doxorubicin was similar in BC-19/neo or BC-19/PKC gamma cells after either 2-hr or continuous drug exposure, and co-treatment with phorbol dibutyrate increased resistance to doxorubicin 4-fold in both cell lines. Phosphorylation of PGP was similar in both cell lines and drug accumulation was not affected by overexpression of PKC gamma. These results demonstrate that transfection of PGP-expressing cells with an atypical isoform of PKC does not confer increased MDR, and they suggest that the regulation of PGP is phenotype specific with respect to the isoform of PKC.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

[Immunogenetic and molecular genetic studies on ocular diseases].

The immunogenetic mechanisms of various ocular diseases were investigated utilizing recently developed molecular biological and molecular genetic techniques. It was revealed that HLA-B 51 was closely associated with Behçet's disease. Investigation of genetic polymorphism of TNF-beta (tumor necrosis factor-beta) showed that 95% of Behçet's disease patients had the 10.5 kbp Nco I fragment. It was therefore concluded that the gene of susceptibility to Behçet's disease is located between HLA-B and TNF-beta loci on the short arm of chromosome 6. Similar studies of HLA-DNA typing in Harada's disease frequently seen in Japan showed that frequencies of HLA-DRB1 * 0405, HLA-DQA1 * 0301 and HLA-DQB1 * 0401 were significantly increased in patients compared with normal controls. These data suggested that those who have serine at position 57 of HLA-DR, glutamic acid at position 70 and aspertic acid at position 71 of HLA-DQ respond to certain unknown agents significantly more than those without them, thus leading to the development of Harada's disease. The same HLA association was observed between Harada's disease and sympathetic ophthalmia, and the immunogenetic mechanism was thought to be similar in both diseases. Recent immunogenetic and molecular genetic investigations on various ocular diseases have shed new light not only on the genetic individual susceptibility and biased racial differences, but also on the diagnosis of the ocular diseases, reclassification of disease entities according to HLA associations, and judgement of disease prognosis. Further progress of molecular medicine may make it possible to treat various intractable ocular diseases by gene therapy in the near future.

Amino Acid Sequence↗
PubMed1992

[A case of isoniazid (INH)-induced pneumonitis].

A 58-year-old man was referred for the evaluation of a lung nodule on chest X-ray. On admission, chest X-ray showed a solitary nodule with cavitation in the left lung field. Histological examination revealed epithelioid cell granulomas and the diagnosis of pulmonary tuberculosis was made. He was treated with INH, ethambutol (EB), and rifampicin (RFP). On the 16th day of treatment, he developed dry cough and high fever. On the 20th day, dyspnea developed and PaO2 was decreased to 38.2 Torr. Chest X-ray showed new widespread infiltrates in both lung fields and bilateral pleural effusions. The size of the cavitary lesion was decreased. Transbronchial biopsy specimen showed slight interstitial thickening, lymphocyte infiltration, and multiple granulomas. Drug lymphocyte stimulation test was positive only with INH (230%). INH-induced pneumonitis was highly suspected. All drugs was discontinued and hydrocortisone 2400 mg daily was started. He soon became afebrile, and dyspnea and dry cough resolved. Chest X-ray film showed resolution of infiltrative shadows. He was subsequently successfully treated with streptomycin, EB, and RFP without any adverse effects. To our knowledge, this is the sixth reported case of INH-induced pneumonitis.

Alveolitis, Extrinsic Allergic↗