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Biomedical subjects

T Ohno

Publications and source records attributed to T Ohno.

At least 577 records · Page 32Linked to original sources
PubMed1990

Comparative studies on FcR (FcRII, FcRIII, and FcR alpha) functions of murine B cells.

Distribution of FcR II, FcRIII, and FcR alpha on murine splenic B cells was examined by using FITC-labeled heat-aggregated IgG of each subclass and IgA. Almost 60 to 80% of B cells expressed both FcRII and FcRIII. However, FcR alpha was expressed on only a small proportion (6%) of B cells that co-expressed FcRII. By inhibition assays with the use of cold IgG of each subclass and IgA in addition to anti-FcRII mAb (2.4G2), it was found that IgG1, IgG2a, and IgG2b utilized the same receptor (FcRII), whereas IgG3 and IgA bound only to their unique receptors, FcRIII and FcR alpha, respectively. Immune complexes IC prepared by IgG1, IgG2a, IgG2b, and IgA anti-TNP mAb with TNP-coupled SRBC inhibited the polyclonal Ig secretion and proliferative responses of B cells stimulated with either IL-4 or LPS. The inhibition of B cell activation was associated with the blockade of the membrane depolarization. Moreover, IC prepared by these antibodies caused production of suppressive B cell factor (SBF) as is the case with rabbit IgG antibody to SRBC, and SBF thus prepared regulated antibody responses in an isotype-nonspecific manner. In contrast, no inhibition for these responses or production of SBF was attained by the IC of IgG3 antibody. We concluded that FcRII and FcR alpha mediates a suppressive signal for B cells by acting on the initial step of activation, whereas FcRIII lacks this activity.

Animals↗
PubMed1990

Characterization of prolidase I and II from erythrocytes of a control, a patient with prolidase deficiency and her mother.

Prolidase I (EC 3.4.13.9) was purified to homogeneity from the erythrocytes of a normal human (control) and the patient's mother, and prolidase II from erythrocytes of a control and the patient's mother, and prolidase from the patient's erythrocytes was also highly purified. The various properties of the patient's prolidase were compared to those of prolidase from a control and the patient's mother. Prolidase I from a control and the patient's mother had a molecular weight of about 112,000, and was composed of two subunits with an identical molecular weight of 56,000. The Km values for Gly-Pro of the control's and the patient's mother's prolidase I were 2.90 +/- 0.22 and 2.88 +/- 0.27 mM, but the Vmax values for Gly-Pro of the mother's enzyme was reduced about 30% compared to that of control enzymes (mother: 6.02 units/mg protein, control: 22.21 units/mg protein). Isoionic points of these enzymes by chromatofocusing were pH 4.6 approximately 4.7. Prolidase II from the control and the patient's mother, and the patient's prolidase had a molecular weight of about 185,000, and was composed of two subunits with an identical molecular weight of 95,000. The Km and Vmax values for various substrates of prolidase II from a control and the patient's mother, and the patient's prolidase were almost the same.

Chromatography, Gel↗
PubMed1990

Tumor growth inhibitory activity of a lymphocyte blastogenesis inhibitory factor.

A lymphocyte blastogenesis inhibitory factor (LBIF) has been characterized as an immunoregulatory molecule, especially on the T-lymphocyte proliferation. Using fast protein liquid chromatography-purified LBIF, we examined the effect of LBIF on the proliferation of various 18 tumor cell lines in vitro in comparison with those of interferon-alpha, interferon-gamma, tumor necrosis factor-alpha, transforming growth factor-beta 1, or interleukin 1 alpha/beta. We showed here that LBIF strongly inhibited the proliferation of various tumor cell lines irrespective of cell lineage or species. LBIF was effective on a wider spectrum of tumor cell lines than other cytokines tested here. The inhibition resulted from cytotoxic or cytostatic effects, depending on individual characteristics of tumor cell lines. Five cell lines showed insensitivity against LBIF activity, suggesting a plausible involvement of LBIF receptor molecules to transduce LBIF signals. These results suggest that LBIF may play important roles in regulating cell growth.

Adjuvants, Immunologic↗
PubMed1990

Abnormal behavior of gamma-committed B lymphocytes probed by a lymphocyte blastogenesis inhibitory factor in autoimmune MRL mice.

Recently, we have characterized a lymphocyte blastogenesis inhibitory factor (LBIF) which was purified from the culture supernatant of a human histiocytic lymphoma U-937 (Sugimura, K. et al., Eur. J. Immunol. 1989. 19: 1357). In this study, we investigated the effect of LBIF on the antibody production of autoimmune MRL mice in vitro. We demonstrated here that (a) LBIF inhibited the IgM, IgG and IgA antibody responses of lipopolysaccharide (LPS)-stimulated spleen cells of normal BALB/c mice, (b) in the case of old autoimmune MRL/Mp-lpr/lpr (MRL/l) and MRL/Mp-(+)/+ mice, however, LBIF inhibited IgM and IgA but not IgG responses of LPS-stimulated spleen cells, (c) the antibody production of all IgG subclasses, IgG3, IgG1, IgG2b and IgG2a, was not sensitive to LBIF inhibitory activity in these autoimmune mice, (d) in young MRL mice (3-5-week-old MRL/l), which were phenotypically normal, LPS-induced antibody production of all isotypes (IgM, IgG and IgA) was strongly inhibited by LBIF as shown in normal BALB/c mice and (e) in the case of 7-week-old MRL/l the insensitivity to LBIF was concomitant with the appearance of gamma + B lymphocytes. Thus, by employing LBIF as a probe, this study showed a correlation between the pathogenesis of MRL autoimmune disease and the lack of LBIF sensitivity of hyperactive B lymphocytes and suggested that the intrinsic abnormality of autoimmune MRL B lymphocytes might be confined to gamma- but not mu- or alpha-committed B cells.

Animals↗
PubMed1990

N-nitrosamines in gastric juice of patients with gastric ulcer before and during treatment with histamine H2-receptor antagonists.

The clinical implications of N-nitrosamines (NAs) were studied by analyzing their concentration in the gastric juice of 72 healthy subjects and 279 patients with gastric ulcer before and during treatment with histamine H2-receptor antagonists. NAs were measured by combined gas chromatography and thermal energy analyzer. The detection ratios of N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) in the patients were 35.3% and 34.6%, respectively, which were significantly higher than the corresponding values in healthy subjects (19.4% and 16.7%, P less than 0.01). Analysis among the patients showed that this trend was mainly due to higher values in patients who were given histamine H2-receptor antagonists, as their detection ratios increased to 40.2% (NDMA) and 39.9% (NDEA). Patients without histamine H2-receptor antagonists showed moderate increases of detection ratios (NDMA; 24.2% NDEA; 22.6%) compared with healthy controls. The differences in these values between those receiving and not receiving histamine H2-receptor antagonists were statistically significant (P less than 0.01). The maximum concentrations of NDMA and NDEA were 7.9 and 9.8 ng/ml in patients, and 1.2 and 1.3 ng/ml in healthy subjects (the difference between the 2 groups P less than 0.02). These results indicated that patients with gastric ulcer had higher detection ratios and concentrations of NDMA and NDEA in gastric juice and that, while significant increases occurred during treatment with histamine H2-receptor antagonists, the extent of increase was below toxic or experimental carcinogenic levels.

Adult↗
PubMed1990

N-nitrosamines in the stomach with special reference to in vitro formation, and kinetics after intragastric or intravenous administration in rats.

To study the implications of nitrosation in the stomach, the formation of N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) from nitrite and secondary amines was examined in vitro under conditions simulating gastric juice. Kinetics of NDMA were investigated after intragastric or intravenous administration of 0.2 mg/kg of NDMA in rats. NDMA and NDEA were measured using combined gas chromatography and thermal energy analyzer. Nitrite levels in human gastric juice were less than 10 micrograms/ml. Optimal pH for nitrosation was between 2.0 to 3.5. Nitrosamine formation reached maximum concentration at 3 to 6 hours. The maximum ratios of nitrosation were 0.15 and 0.11% in NDMA/nitrite and NDEA/nitrite, respectively. In the kinetic study, the highest blood levels of NDMA were observed at 5 min, reaching 174 +/- 40 and 374 +/- 40 ng/ml after administration into the stomach and duodenum, respectively. Then they decreased exponentially and were not detectable after 4 hours. Tissue levels of NDMA in the liver, spleen, kidney, lung and brain showed 70% of the blood levels. Urinary excretion of intravenously administered NDMA during the first 4 hours was less than 0.2%. These results supported the hypothesis that nitrosation occurred in gastric juice under optimal conditions, and indicated that nitrite levels were the limiting factor for nitrosation. Quick disappearance from the gastrointestinal tract suggested that the pathologic implication of nitrosamines formed in the stomach could be important for other organs.

Animals↗
PubMed1990

Nucleolar organizer regions in rat urinary bladder tumors induced by N-butyl-N-(4-hydroxybutyl)nitrosamine.

The number of nucleolar organizer regions (NORs) stained by the one-step silver colloid method was measured in preneoplastic and neoplastic bladder lesions induced by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in rats. Male ACI/N rats, 6 weeks of age, were given 0.05% BBN in drinking water for 5, 8, 12, 18 and 30 weeks to induce preneoplastic and neoplastic transitional cell lesions. The mean numbers of silver-stained NORs (AgNORs) in such lesions were as follows: untreated transitional epithelium (n = 6), 1.26 +/- 0.09; transitional cell epithelium outside focal lesions (n = 10), 1.75 +/- 0.10; simple hyperplasia (n = 10), 2.01 +/- 0.15; papillary or nodular (PN) hyperplasia (n = 10), 2.15 +/- 0.19; transitional cell papilloma (n = 5), 2.37 +/- 0.12; transitional cell carcinoma (n = 5), 3.52 +/- 0.23. Thus, the mean number of AgNORs showed a step-wise increase from untreated and treated, histologically normal transitional epithelium through simple hyperplasia and PN hyperplasia to transitional cell papilloma and carcinoma. These results suggest that the mean number of AgNORs may reflect the proliferative nature of bladder lesions induced by BBN, as reported in preneoplastic and neoplastic lesions in other organs. PN hyperplasias were classified into two types based upon the mean number of AgNORs, indicating that they include reversible and irreversible changes in contrast with simple hyperplasia which is reversible change.

Animals↗
PubMed1990

A lymphocyte blastogenesis inhibitory factor (LBIF) reversibly arrests a human melanoma cell line, A375, at G1 and G2 phases of cell cycle.

A lymphocyte blastogenesis inhibitory factor, LBIF, has been found in the culture supernatant of a human macrophage-like cell line, U937. The factor has been purified by fast protein liquid chromatography. Partial amino acid sequencing analysis showed that LBIF was a novel immunoregulatory factor. Recent study has demonstrated that LBIF possesses a remarkable tumor growth inhibitory activity. In this study, the cell growth inhibitory activity of LBIF was characterized on the proliferation of a human melanoma cell line A375 in vitro. LBIF strongly inhibits the proliferation of A375 cells. The inhibitory activity was cytostatic and reversible by Day 5 although the lethal effect became apparent at Day 7. Cell cycle analysis by flow cytometry showed that LBIF arrested A375 cells at both G1 and G2/M phases. Mitotic index analysis indicated that A375 cells were arrested in G1 and G2 phases. LBIF function was not attributed to the elevation of intracytoplasmic cyclic-AMP levels. Thus, these results suggest that LBIF plays an important role in controlling cell cycle and there is a similarity between the mechanisms of G1 and G2 arrests in eukaryotic cell proliferation. LBIF-induced reversible cell-cycle arrest of A375 cells can be a useful system to analyze the signal transduction for cell proliferation and cell-cycle arrest.

Cell Division↗
PubMed1990

Genetic heterogeneity in blast crisis of chronic myelocytic leukemia.

Fourteen patients with lymphoid and mixed blast crisis (BC) of chronic myelocytic leukemia were studied by immunophenotyping and genotyping. Rearrangements of immunoglobulin heavy chain (IgH), T-cell receptor (TcR) gamma and TcR beta genes were detected in all 14, in nine and in four patients, respectively. Interestingly, more than two rearranged bands of IgH gene in three lymphoid BC and two rearranged bands with germ line band in 1 biphenotypic BC indicated the genetic heterogeneity of the blasts. Some blastic transformations are thought to occur at a more immature stage of hematopoietic differentiation than that indicated by the phenotype and genotype of BC cells.

Antigens, Differentiation↗
PubMed1990

Elevated argininosuccinate synthetase activity in adult T leukemia cell lines.

Argininosuccinate synthetase (ASS) is a ATP-dependent and rate-limiting enzyme of the urea cycle which catalyzes L-citrulline to L-arginine in combination with argininosuccinate lyase (ASL). We demonstrate here that (a) human normal T and B lymphocytes did not express ASS activity, (b) however, three adult T leukemia (ATL) cell lines tested here exhibited significant elevation of ASS activity, and (c) ASL activity remained relatively constant in normal lymphocytes and various leukemia cell lines. These results suggest that the ASS expression of peripheral blood lymphocytes is of value as a diagnostic marker of leukemia including ATL. The implication of these results is discussed.

Arginine↗
PubMed1990

Levels of total cyanide and NaCl in surface waters adjacent to road salt storage facilities.

Concentrations of Na, Cl and total cyanide (simple+complex forms of cyanide) in surface waters adjacent to uncovered, outdoor sand-salt storage facilities were monitored for the calendar year 1988. Runoff of deicing salt from these unprotected sand-salt piles resulted in Cl concentrations up to 13,500 mg liter(-1) in surrounding surface waters indicating substantial leaching of road salt from sand-salt storage lots. The use of sodium hexacyanoferrate (II) as an anti-caking agent in road salt resulted in up to 200 microg liter(-1) total cyanide (CN) in surface waters adjacent to sand-salt piles. Concentrations of Na and Cl were highest during the summer months whereas the concentrations of total CN were highest during the autumn months. The observed concentrations of total CN were less than the calculated maximum concentrations based on total CN content of pure road salt indicating that sodium hexacyanoferrate(II) was being adsorbed during overland flow onto soils and/or sediments of the wetlands. A laboratory adsorption study using five soils and a road salt solution showed that the soils adsorbed from 25 to 83% of the sodium hexacyanoferrate(II) present in the soil-road salt suspensions. The percentage of sodium hexacyanoferrate(II) adsorbed on soils increased with decreasing soil pH.

Journal Article↗
PubMed1990

A mouse monoclonal antibody reactive preferentially with human IgM lambda.

In analyzing mouse monoclonal antibodies (mAb) against a human IgM kappa paraprotein, we found an unusual mAb (LP4; gamma 2b kappa isotype) that reacted in an enzyme linked immunosorbent assay with all 5 IgM lambda but not with 8 IgM kappa or other myelomas. Neither isolated mu heavy nor lambda light chains were reactive with LP4 mAb. By immunofluorescence, LP4 mAb identified approximately 30% of IgM+ B cells and approximately 40% of mitogen-stimulated, IgM+ plasma cells from 4-7 normal blood samples. All LP4+ cells were IgM+. Biosynthetic analysis of the plasma cells revealed that LP4 mAb recognized most IgM lambda and a very minor proportion of IgM kappa molecules. This mAb provides a useful marker for the analysis of pre-B and B cell differentiation.

Animals↗
PubMed1990

Inhibitory effect of sinigrin and indole-3-carbinol on diethylnitrosamine-induced hepatocarcinogenesis in male ACI/N rats.

The modifying effects of sinigrin (Sin) and indole-3-carbinol (I3C) on the hepatocarcinogenesis induced by diethylnitrosamine (DEN) were investigated in male ACI/N rats. Rats were divided into six groups: group 1 was given DEN (40 p.p.m.) in the drinking water for 5 weeks, starting at 7 weeks of age; group 2 was treated with DEN and diet containing 1200 p.p.m. Sin; group 3 received DEN and diet containing 1000 p.p.m. I3C; group 4 was given Sin diet alone; group 5 was given I3C diet alone; and group 6 served as controls. The diet containing Sin or I3C was fed to the rats starting at 6 weeks of age until 1 week after the carcinogen exposure. At termination of the experiment (week 29), the incidences of iron-excluding altered foci (11.22 +/- 3.22/cm2) and liver cell tumors (6/12, 50%) and the tumor multiplicity (0.9/rat) in rats of group 2 were significantly smaller than those of group 1 (foci incidence, 48.33 +/- 6.34/cm2, tumor incidence, 10/10, 100%; multiplicity, 9.5/rat) (P less than 0.02). Similarly, the incidence of iron-excluding hepatocellular foci (17.65 +/- 4.67/cm2) and tumor multiplicity (2.4/rat) with a slight reduction of tumor incidence (9/12, 75%) in rats of group 3 were significantly lower than those of group 1 (P less than 0.001). There were no liver cell neoplasms in rats of groups 4, 5 and 6. Thus, Sin and I3C inhibited the hepatocarcinogenesis induced by DEN when they were administered concurrently with the carcinogen.

Animals↗
PubMed1990

Inherited hyperactivation of L-arginine synthesis in gamma + B lymphocytes of systemic autoimmune MRL mice.

The hyperactivation of B lymphocytes of MRL mice, which are an animal model for human systemic lupus erythematosus (SLE), is characterized as the preferential propagation of gamma + B lymphocytes and IgG overproduction followed by aging. Little is known about the molecular mechanisms, although the involvement of cytokines has been extensively investigated. Here we now show that gamma-committed B lymphocytes selectively exhibit a highly elevated L-citrulline metabolism while mu or alpha-committed B lymphocytes show a normal level in autoimmune MRL mice. L-Arginine proportionally supports the lymphocyte proliferation and antibody production in a concentration-dependent fashion (approximately 100 microM). However, normal murine lymphocytes show an extremely low activity of citrulline metabolism, which converts L-citrulline to L-arginine. Thus, these results suggest that the overexpression of elevated citrulline metabolism is associated with gamma chain expression, and this elevation may enable gamma-committed B lymphocytes to preferentially propagate and overproduce IgG compared with mu or alpha-committed B lymphocytes.

Animals↗
PubMed1990

Analyses of ornithine decarboxylase antizyme mRNA with a cDNA cloned from rat liver.

Ornithine decarboxylase antizyme is a unique inhibitory protein induced by polyamines and involved in the regulation of ornithine decarboxylase. A cDNA was isolated from a rat liver cDNA library by the screening with monoclonal antibodies to rat liver antizyme as probes. The expression products of the cDNA in bacterial systems inhibited rat ornithine decarboxylase activity in a manner characteristic of antizyme and rabbit antisera raised against its direct expression product reacted to rat liver antizyme, confirming the authenticity of the cDNA. On RNA blot analysis with the cDNA probe, an antizyme mRNA band of 1.3 kb was detected in rat tissues. Antizyme mRNA did not increase upon administration of putrescine, an inducer of antizyme, and its half-life after actinomycin D treatment was as long as 12 h in rat liver, suggesting that antizyme mRNA is constitutively expressed and antizyme synthesis is regulated at the translational level. Similar-sized mRNAs hybridizable to the cDNA were also found in various mammalian and non-mammalian vertebrate tissues under physiological conditions. In addition, chicken and frog antizymes showed immunocrossreactivity with rat antizyme. The ubiquitous presence and the evolutionally conserved structure of antizyme in vertebrate tissues suggest that it has an important function.

Animals↗
PubMed1990

Estimation of right ventricular pressure by 201Tl scintigraphy in paediatric cardiac disease.

To estimate right ventricular overload in paediatric cardiac disease, 201Tl scintigraphy was used to quantify right ventricular uptake. Six methods for calculating the 201Tl right-to-left ventricular uptake ratio (TRL) were compared, based on the location of regions of interest (ROIs), use of total count or mean count density, and the ROI-based method or profile method. When the TRL was compared with the right-to-left ventricular peak systolic pressure ratio (RVP/LVP), the mean count density method using entire right and left ventricular ROIs seemed to be appropriate, considering its simplicity, reproducibility and regression line. The linear regression line was RVP/LVP = 1.15 x TRL - 0.13 (n = 15, P = -0.0001), and RVP(mm Hg) = 162 x TRL - 33 (n = 15, P = 0.0001). In four patients with pulmonary stenosis, the changes of TRL were in good agreement with the right ventricular pressure changes after percutaneous balloon valvuloplasty. Thus, evaluation of thallium scintigraphy using this quantitative method can be a simple and effective way to evaluate patients with right ventricular pressure overloading.

Adolescent↗