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Biomedical subjects

Y Niho

Publications and source records attributed to Y Niho.

At least 217 records · Page 12Linked to original sources
PubMed1995

Urinary C4 excretion in systemic lupus erythematosus.

The fourth component of complement (C4) in urine was measured in 19 patients with systemic lupus erythematosus (SLE). Urinary C4 was detectable in all SLE patients using an enzyme linked immunosorbent assay. In 11 of 13 patients whose urinary C4 was serially measured, a decrease of urinary C4 was found in parallel with a decrease of disease activity of SLE. In the remaining 2 patients, the amount of C4 increased preceding a flare-up of the disease. The measurement of urinary C4 may be useful in evaluating the disease activity of SLE in individual patients and sometimes in predicting the flare-up of the disease. The specific hemolytic activity of excreted C4 and Western blotting analysis showed that urinary C4 consisted mainly of degraded fragments of C4. In two cases, camostat, a serine protease inhibitor, rapidly decreased the urinary C4 excretion, suggesting that the complement activation occurred in the glomerulus in lupus nephritis.

Adolescent↗
PubMed1995

Protective effect of granulocyte colony-stimulating factor against T-cell-meditated lethal shock triggered by superantigens.

The bacterial superantigens (SAg), toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxin B (SEB), are powerful T-cell stimulators, triggering systemic release of lymphokines causing lethal shock in D-galactosamine (D-Gal)-sensitized mice. We show that pretreatment with recombinant human granulocyte colony-stimulating factor (rhG-CSF) protects mice against T-cell-mediated SAg-shock. In mice challenged with D-Gal/TSST-1, lethal shock was caused within 30 hours. In contrast, animals pretreated with two consecutive subcutaneous injections of 2 micrograms rhG-CSF with a 12-hour time interval showed only marginal signs of illness and no lethality after challenge with D-Gal/TSST-1. Mice treated with 5 micrograms rhG-CSF either 12 or 6 hours in advance also survived otherwise lethal doses of D-Gal/TSST-1. The protective effects of rhG-CSF pretreatment was also evident against lethal doses of D-Gal/SEB challenge and this protection was accompanied by suppression of systemic interleukin-2. However, rhG-CSF affected neither the proliferative responses of SAg-reactive T cells in vivo or in vitro nor their interleukin-2 production in vitro, implying that rhG-CSF may indirectly interfere with cytokine synthesis in T cells but not with T-cell-SAg binding itself. These results represent another beneficial effect of rhG-CSF as an anti-inflammatory agent against T-cell-mediated toxicity triggered by SAg.

Animals↗
PubMed1995

Functional expression of Fas antigen (CD95) on hematopoietic progenitor cells.

We investigated the expression of an apoptosis-associated antigen (Fas) (CD95) on hematopoietic progenitor cells in the presence or absence of interferon-gamma (IFN-gamma) and/or tumor necrosis factor-alpha (TNF-alpha). CD34+ cells freshly isolated from bone marrow did not express Fas. However, IFN-gamma and/or TNF-alpha induced the expression of both the mRNA of Fas and Fas itself in a dose-dependent fashion on the surface of CD34+ cells after 48 hours of serum-free culture. IFN-gamma and TNF-alpha had a synergistic effect on the induction of Fas, when both cytokines were added to the culture. The TNF-alpha-induced Fas expression is mediated by p55 TNF-alpha receptor. CD34+ cells cultured in medium alone or with stem cell factor (SCF) showed some slight expression of Fas. When anti-Fas antibody (IgM) was added to CD34+ cells after the induction of Fas expression, CD34+ cells underwent apoptosis, as shown by a decrease in the number of viable cells, morphologic changes, the induction of DNA fragmentation, and a decrease in the number of colony-forming cells (CFC) including colony-forming unit granulocytes/macrophages (CFU-GM) and burst-forming unit erythroids (BFU-E). These observations indicate that IFN-gamma and/or TNF-alpha, well known as negative hematopoietic regulators, induce functional Fas on hematopoietic progenitor cells. The suppression of hematopoiesis by negative hematopoietic regulators may be mediated in part by Fas induction.

Antigens, Surface↗
PubMed1995

Inhibition of cis-diamminedichloroplatinum (II)-induced DNA interstrand cross-link removal by 7-ethyl-10-hydroxy-camptothecin in HST-1 human squamous-carcinoma cells.

The combination of cis-diamminedichloroplatinum(II) (CDDP) and 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin (CPT-11), a topoisomerase-I inhibitor, has been shown to be synergistic in vitro and clinically active against several human cancers refractory to chemotherapy. To elucidate the mechanism of the synergistic cytotoxicity of CDDP and 7-ethyl-10-hydroxycamptothecin (SN-38), an active metabolite of CPT-11, we studied the interaction of these agents using an HST-1 human squamous-carcinoma cell line. Cells were exposed to the IC50 concentration of SN-38 (5.0 ng/ml) for 1 hr and various concentrations of CDDP for 1 hr in several different treatment schedules. SN-38 augmented the anti-tumor activity of CDDP in all schedules, with maximal synergy observed with simultaneous administration. Evaluation of the kinetics of the removal of DNA interstrand cross-links, measured by alkaline elution, showed significant reduction of this removal in the cells exposed to SN-38 and CDDP, as compared with the cells exposed to CDDP alone. No differences, however, were found in the initially attained level of DNA interstrand cross-links induced by CDDP between these cells. Moreover, the intracellular accumulation of platinum measured by atomic-absorption spectrophotometry, was virtually identical between these cells. These results indicate that SN-38 can modulate the removal of platinum-DNA adducts, thereby potentiating the cytotoxicity of CDDP, suggesting a critical role for topoisomerase I in the repair of DNA interstrand cross-links.

Antineoplastic Agents, Phytogenic↗
PubMed1995

HLA DRB4 0101-restricted immunodominant T cell autoepitope of pyruvate dehydrogenase complex in primary biliary cirrhosis: evidence of molecular mimicry in human autoimmune diseases.

We established six T cell clones specific for pyruvate dehydrogenase complex (PDC)-E2 peptides from four different patients with primary biliary cirrhosis using 33 different peptides of 17-20 amino acid residues corresponding to human PDC-E2 as stimulating antigens. The minimal T cell epitopes of these six T cell clones were all mapped to the same region of the PDC-E2 peptide 163-176 (GDLLAEIETDKATI), which corresponds to the inner lipoyl domain of PDC-E2. The HLA restriction molecules for this epitope were all identified as HLA DRB4 0101. The common essential amino acids of this epitope for these T cell clones were E, D, and K at positions 170, 172, and 173, respectively; other crucial amino acids for this epitope differed in each T cell clone. In addition, the alanine-substituted peptides at positions 170 and 173, but not 172, inhibited the proliferation of all T cell clones induced by the original peptide of human PDC-E2 163-176, indicating that amino acid D at position 172 is a critical MHC-binding site for all T cell clones tested. Interestingly, all T cell clones reacted to PDC-E2 peptide 36-49 (GDLIAEVETDKATV), which corresponds to the outer lipoyl domain of human PDC-E2. Furthermore, one T cell clone cross-reacted with exogenous antigens such as Escherichia coli PDC-E2 peptide 31-44/134-147/235-248 (EQSLITVEGDKASM), which has an EXDK sequence. This is a definite demonstration of the presence of molecular mimicry at the T cell clonal level in human autoimmune diseases. It is also considered possible to design peptide-specific immunotherapy based on the findings of T cell autoepitopes in primary biliary cirrhosis.

Adult↗
PubMed1995

Direct tumorigenic conversion of human gallbladder carcinoma cells by v-src but not by activated c-H-ras oncogene.

The roles of activated ras and src oncogene products in the acquisition of fully neoplastic phenotype by human gallbladder adenocarcinoma cells were investigated by co-transfecting non-tumorigenic HAG-I human gallbladder carcinoma cells with the pSV2neo plasmid and a plasmid carrying either activated c-H-ras or v-src oncogene. G418-resistant clones were isolated and assessed for the acquisition of anchorage-independent growth potential. Neither the 10 established clones transfected with pSV2neo alone nor the 17 clones transfected with activated c-H-ras, including 4 clones expressing the mutated p21H-ras protein, could form colonies in soft agar. By contrast, out of 10 clones transfected with v-src, 2 formed colonies in soft agar and produced tumors in athymic nude mice, the resulting progressive neoplasms being poorly differentiated adenocarcinomas. These tumorigenic clones were shown to have v-src DNA and mRNA levels with p60v-src protein, but there were no significant chromosomal alterations following tumorigenic conversion. Moreover, herbimycin A, a selective src-kinase inhibitor, markedly reduced clonogenic growth of these cells in soft agar rather than monolayer growth, suggesting that anchorage-independent growth of the v-src-transformed HAG-I cells might be driven directly by p60v-src kinase activity. Taken together, our data suggest that the fully neoplastic conversion of HAG-I cells depends on src-related tyrosine-kinase activity, but not solely on the function mediated by activated ras, thus providing evidence of an src-related signaling pathway for the acquisition of tumorigenic potential by human gallbladder adenocarcinoma cells.

Adenocarcinoma↗
PubMed1995

A peptide-based human T cell leukemia virus type I vaccine containing T and B cell epitopes that induces high titers of neutralizing antibodies.

We have recently identified the principal linear neutralizing B cell epitopes of human T cell leukemia virus type I (HTLV-I) on the envelope protein gp46, amino acids (aa) 187-199, by using a number of human mAbs. We therefore propose that this region would be a good candidate for a peptide-based HTLV-I vaccine. To develop a peptide-based vaccine that can induce a high titer of neutralizing Abs against HTLV-I, we first synthesized peptides of various lengths containing aa187-199. Because the addition of gp46 aa181-186 or aa200-210 to either the N-terminus or C-terminus of SP187-199 did not alter the antigenicity of the principal neutralizing determinant, we prepared two peptide-based vaccines, MAP181-203 and MAP181-210, by conjugating SP181-203 and SP181-210 with a branched polylysine oligomer. In rabbits, X4 to X8 and X8 to X64 titers of the neutralizing Abs were induced by immunization with MAP181-203 and MAP181-210, respectively. Furthermore, high titers of neutralizing Abs (X40 to X320) were elicited in five different strains of rats by immunization with MAP181-210. We also identified the major T cell epitope on gp46 aa194-210 in various strains of rats immunized with MAP181-210. Furthermore, the peripheral T lymphocytes obtained from the majority of HTLV-I-infected patients including HTLV-I-associated myelopathy/tropical spastic paraparesis, adult T cell leukemia/lymphoma, and healthy carriers, proliferated in response to the peptides containing aa194-210. These results indicated that MAP181-210 contains a T cell helper epitope on aa194-210 not only in rats and rabbits, but also in humans with various HLA haplotypes. It is therefore possible that MAP181-210 could become one of the candidates for a peptide-based HTLV-I vaccine for human use.

Amino Acid Sequence↗
PubMed1995

Interleukin-10 selectively inhibits osteoclastogenesis by inhibiting differentiation of osteoclast progenitors into preosteoclast-like cells in rat bone marrow culture system.

Recombinant human interleukin-10 (hIL-10) inhibited the formation of osteoclast-like multinucleated cells in rat whole bone marrow cultures. The effect of hIL-10 on the process of osteoclast formation was further examined, since the process of osteoclast formation includes the proliferation and the differentiation of osteoclast progenitors into mononuclear preosteoclasts and the fusion of preosteoclasts into multinucleated osteoclasts. In the nonadherent bone marrow cell culture system, which was free of stromal cells and formed preosteoclast-like cells, hIL-10 significantly inhibited the formation of preosteoclast-like cells even at a very low concentration (0.5 U/ml). The strong inhibition appeared even after treatment with hIL-10 for only the first 24 h of the culture. However, hIL-10 did not affect the fusion process of preosteoclast-like cells to form osteoclast-like multinucleated cells in the rat coculture system of preosteoclast-like cells with primary osteoblasts. Furthermore, hIL-10 completely inhibited the colony formation induced by granulocyte macrophage colony-stimulating factor (GM-CSF). These findings suggest that the inhibition of osteoclastogenesis by hIL-10 started at the early stage of the differentiation of osteoclast progenitors to preosteoclasts.

Animals↗
PubMed1995

High incidence of a polymorphic variant of erythrocyte membrane protein, Band 3-Memphis, on a western Japanese island.

Band 3 is the major membrane protein of erythrocytes, which binds membrane skeletal proteins, glycolytic enzymes, and hemoglobin and transports various kinds of anions. Band 3-Memphis is a variant of Band 3, the amino terminal fragment of which depicts a slow electrophoretic mobility on sodium dodecyl sulfate-polyacrylamide gel. The frequency of Band 3-Memphis varies among populations, with a higher frequency among the Japanese. We investigated the frequency of Band 3-Memphis in a western Japanese island which is relatively isolated from the main islands, finding that the frequency of Band 3-Memphis of the inhabitants of this island is significantly higher than the frequency of the Japanese based on the survey in Kyushu Island. This indicates that there may be differences of population in the frequency of Band 3-Memphis in Japan and that Band 3-Memphis may be a good marker to genetically differentiate each population.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1995

Analysis of c-kit expression of human erythroleukemia cell line, HEL: clonal variation and relationship with erythroid and megakaryocytic phenotype.

The proto-oncogene c-kit encodes the receptor for a stem cell factor. We examined HEL, a human erythroleukemia cell line, in order to clarify the correlation between the c-kit receptor (KR) expression and lineage-specific phenotype. Although HEL cells are known to express KR, we found two relatively distinct HEL cell populations in terms of KR expression. We then subcloned HEL cell lines with clone sorting on the basis of KR expression and compared their various characteristics. The highly KR-expressing subline, HEL-P1, expressed a high level of glycophorin A (GPA), a known erythroid lineage marker. HEL-N1, in which most of the cells were KR-negative, showed a higher megakaryocytic lineage marker CD41b expression than HEL-P1. However, the expression of granulomonocytic lineage markers were not significantly different between the two subclones. Cell growth rate and cell cycle analysis also did not detect significant differences between the sublines. HEL-P1 cells gradually lost their KR expression in serum-containing culture, while the percentage of KR-positive HEL-N1 cells increased in serum-free culture. These observations indicate that KR expression was associated with the synchronous expression of GPA and inversely correlated with CD41b, and reversible transitions between KR-positive cells and KR-negative cells exist. We suggest that KR plays an important part in commitment of erythroid and megakaryocytic precursor cells.

Antigens, CD↗
PubMed1995

Effects of Bestatin on hematopoiesis in long-term human bone marrow cultures.

The effects of Bestatin (Ubenimex, UBX) on normal hematopoiesis were investigated using long-term bone marrow cultures (LTBMC) to determine whether it might enhance hematopoiesis over a long period, as well as induce the release of cytokines. LTBMC were inoculated with 0.1 or 1.0 microgram/ml of UBX at the onset of culture and was added at each weekly medium change. The cellularity and the content of the progenitors in nonadherent layer were examined each week for 5 weeks; those from the adherent layer were examined at week 5. The number of the nucleated mature cells and that of the myeloid progenitors from the nonadherent layer increased significantly (approximately two-fold) following treatment with UBX vs controls. The total number of colonies and the number of myeloid progenitors, but not that of erythroid progenitors, from the adherent layer increased significantly (about 1.5-fold) following treatment with 1.0 microgram/ml UBX. The level of interleukin-6 (IL-6) in the culture supernatants was significantly increased one day after the addition of 1.0 microgram/ml UBX. Findings indicate that UBX stimulated both the production of mature cells and myeloid progenitors on normal hematopoiesis in LTBMC. This was mediated by an indirect action via IL-6 production.

Aminopeptidases↗
PubMed1995

Allogeneic peripheral blood stem cell transplantation for treatment of induction failure in a patient with Philadelphia chromosome-positive acute lymphoblastic leukemia.

We report a successful case of allogeneic peripheral blood stem cell transplantation (PBSCT) for the treatment of primary induction failure in acute lymphoblastic leukemia (ALL). The patient was a 46-year-old male with Ph-positive ALL and failed to achieve complete remission (CR). His HLA genotypically identical brother refused to donate bone marrow. Instead, PBSCs were collected by apheresis from the brother after administration of G-CSF at a dose of 10 micrograms/kg. For allogeneic PBSCT, the patient was conditioned with marrow ablative chemotherapy and received the PBSC harvest containing 7.8 x 10(4)/kg of CFU-GM, 1.8 x 10(6)/kg of CD34-positive cells and 2.7 x 10(8)/kg of T lymphocytes. After transplant, the neutrophil count exceeded 0.5 x 10(9)/l on day 16 and the platelet count exceeded 20 x 10(9)/l on day 22. CR was confirmed with tri-lineage engraftment in bone marrow samples on days 28 and 49; disappearance of the Ph-chromosome was documented. Sustained engraftment was also confirmed cytogenetically using a variable number of tandem repeat (VNTR) markers. Acute graft-vs.-host disease did not develop with conventional prophylaxis of methotrexate and cyclosporine. However, on day 85 the patient developed leukemia relapse and died on day 97. This clinical trial suggests that allogeneic PBSCT may be an alternative to allogeneic bone marrow transplantation in some limited situations.

Hematopoietic Stem Cell Transplantation↗
PubMed1995

Establishment and structural analysis of human mAb to the E2 component of the 2-oxoglutarate dehydrogenase complex generated from a patient with primary biliary cirrhosis.

We established one Epstein-Barr virus-transformed B cell hybrid clone producing human mAb of the IgG class to the 2-oxoglutarate dehydrogenase complex (OGDC) for the first time from the peripheral B lymphocytes of a patient with primary biliary cirrhosis (PBC). This mAb, designated mAbM37GO37, specifically bound to OGDC and its dissociation constant with OGDC was calculated to be 3.70 x 10(-10) mol/l. mAbM37GO37 stained murine stomach/kidney cryostat sections in a typical immunofluorescence pattern of antimitochondrial antibody (AMA). Western blotting analysis revealed that mAbM37GO37 reacted with an E2 component of OGDC but not with other components of OGDC nor pyruvate dehydrogenase complex (PDC). Furthermore, mAbM37GO37 completely inhibited the enzymatic activity of OGDC. In order to determine the structure and genetic origin of anti-OGDC autoantibody, we cloned and sequenced the Ig heavy and light chain variable regions of mAbM37GO37. This mAb used the VHIII family member, V3-7, and the V kappa IV family member. The amino acid difference between the expressed V genes of this mAb and respective putative germline genes was concentrated within the complementarity determining regions (CDR) rather than the framework regions (FR). The R:S mutation ratio was high in the CDR and low in the FR. These features suggested that the immune response to OGDC is similar to that to exogenous antigen, and that the heavy and light chain variable regions of the anti-OGDC antibody undergo somatic hypermutation through antigen-driven clonal selection. This human mAb to OGDC, which was established for the first time from a patient with PBC and characterized at the molecular level, would be a valuable tool to study the B cell autoepitopes of OGDC, to clone as yet undetermined full length cDNA encoding OGDC and to dissect the autoimmune response to mitochondrial antigens in PBC.

Adult↗
PubMed1995

High serum levels of granulocyte-macrophage colony-stimulating factor in patients with liver cirrhosis and granulocytopenia.

Leucopenia is often observed in patients with liver cirrhosis. We measured levels of serum granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients with liver cirrhosis by a sensitive enzyme linked immunosorbent assay. Eight out of 22 patients with liver cirrhosis had detectable serum GM-CSF (range, 55 to 245 pg/ml:mean, 135 pg/ml). Serum GM-CSF was detected in all patients with a granulocyte count below 2.0 x 10(9)/l, but in only one patient with a granulocyte count above 2.0 x 10(9)/l. Haemoglobin concentration, platelet count, serum albumin, total bilirubin and aminotransferase levels did not correlate with serum GM-CSF levels. These findings may reflect a feedback mechanism between the number of circulating granulocytes and serum GM-CSF levels in patients with cirrhosis.

Adult↗
PubMed1995

Effects of ajmaline on non-sodium ionic currents in guinea pig ventricular myocytes.

The lack of currently available data stimulated us to investigate the electrophysiological effects of ajmaline, a classical class Ia antiarrhythmic agent, on various currents responsible for the action potential plateau and repolarization phases. The whole cell patch clamp recording technique was applied to guinea pig ventricular myocytes. Ajmaline suppressed the Ca2+ current (Ica) in a dose-dependent manner (Kd = 1.2 x 10(-5) M) without affecting the steady-state inactivation kinetics and the voltage dependency of the current-voltage relationship. Ajmaline inhibited the inward portion of the inward rectifying K+ current (IKl). Ajmaline decreased the delayed rectifier K+ current (IK) without altering the activation or deactivation time courses. All these inhibitory effects of ajmaline prolonged the action potential duration in a dose dependent manner. The inhibitory actions of ajmaline on the action potential upstroke and various currents responsible for the plateau and repolarization may contribute to the observed suppression of depolarization-induced abnormal automaticities by this agent.

Action Potentials↗
PubMed1995

Coronary dilating effects of intracoronary nicorandil. Comparison with isosorbide dinitrate.

Although nicorandil, N-(2-hydroxyethyl) nicotinamide dinitrate, is a nitrate ester, its cardiovascular action differs from that of nitrate compounds in several aspects. In this quantitative angiographic study, the acute coronary dilating effect of intracoronary nicorandil (0.25, 0.50, 1.0 mg) was compared with that of isosorbide dinitrate (ISDN; 1.0 mg) in 46 patients with or without ischemic heart disease (IHD). Dose-dependent right coronary dilating action was observed by intracoronary administration of nicorandil without any adverse effects. The same degree of right coronary dilation was achieved by the intracoronary application of equivalent doses of ISDN. We conclude that intracoronary administration of nicorandil is beneficial for the supportive treatment of IHD during coronary artery investigation and intervention without the risk of severe systemic hypotension.

Angina Pectoris↗