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Biomedical subjects

K Eguchi

Publications and source records attributed to K Eguchi.

At least 253 records · Page 14Linked to original sources
PubMed1997

Sequencing of cDNA clones that encode bovine ferritin H and L chains.

The molecular weight of the liver-type subunit (L) of bovine ferritin is much larger than that of the heart-type subunit (H) as determined by SDS-PAGE (L, 20.5 kDa; H, 18.4 kDa). The migration of these two subunits on SDS-PAGE gels, relative to each other, is opposite to that reported for ferritin L and H subunits in other mammalian species (L, 19 kDa; H, 21 kDa). To determine the cause of this anomaly, full-length cDNA clones of the bovine L and H chains were isolated from a bovine spleen gamma gt11 cDNA library and sequenced. The amino acid sequences of the L and H chains of bovine ferritin, deduced from their cDNA sequences, contained open reading frames coding for 174 and 180 amino acid residues with calculated molecular weights of 19,856 and 20,920 Da, respectively. The deduced amino acid sequence of the L chain shows 86%, 84%, 87%, 83% and 83% homology with the amino acid sequences of horse, human, rabbit, rat and mouse L chains, respectively. The H chain displays a higher homology with the human, rat and mouse H chains (91%, 92% and 93%, respectively). In addition, the bovine L chain did not contain the extra octapeptide present in rodent L chains, and bovine, L and H chains did not react with concanavalin A. The bovine L and H chains expressed using a baculovirus expression system showed almost the same mobilities as those of bovine spleen ferritin, respectively, by SDS-PAGE. These results suggest that the much slower mobility of the bovine L chain compared with other mammalian L chains on SDS-PAGE cannot be attributed to insertion(s) of amino acid(s) or peptide(s) into the L chain, to the deletion(s) of them of it or to the addition of carbohydrate chains(s) but may result from significant differences in the binding affinity of SDS for bovine ferritin L chains.

Amino Acid Sequence↗
PubMed1997

Expression of epithelial cadherin and cavernous sinus invasion in human pituitary adenomas.

Pituitary adenomas generally are regarded as benign tumors, although some invade the cavernous sinus and recur. We examined the epithelial cadherin (E-CD) expression in 30 pituitary adenomas (6 with cavernous sinus invasion and 24 without). Immunoreactivity of E-CD were found in all pituitary adenomas but they were very various. The presence of an association between E-CD expression and cavernous sinus invasion was assessed. There were no significant differences in E-CD expression between invasive and noninvasive adenomas. These results suggest that E-CD expression is not associated with cavernous sinus invasion in pituitary adenomas.

Adenoma↗
PubMed1997

Granulocyte colony-stimulating factor receptor expression on human transitional cell carcinoma of the bladder.

Receptors for granulocyte colony-stimulating factor (G-CSFRs) have been confirmed on the cell surfaces of several non-haematopoietic cell types, including bladder cancer cells. This observation has naturally led to the hypothesis that the expression of G-CSFR on these cells may enhance their growth by G-CSF. In this study, the expression of G-CSFR was determined in both established human bladder cancer cell lines and primary bladder cancers. We studied five different human bladder cancer cell lines (KU-1, KU-7, T-24, NBT-2 and KK) and 26 newly diagnosed bladder tumours. G-CSFR mRNA expressions on cultured cell lines were determined using the reverse transcriptase polymerase chain reaction (RT-PCR) method. Furthermore, the G-CSFR binding experiments on the cultured cell lines were conducted using the Na(125)I-labelled G-CSF ligand-binding assay method. Moreover, the G-CSFR mRNA expressions on primary bladder tumour specimens were assessed using the in situ RT-PCR method. Three out of the five cultured cell lines (KU-1, NBT-2 and KK) exhibited G-CSFR mRNA signals when the RT-PCR method was used. The G-CSFR binding experiments showed an equilibrium dissociation constant (K[d]) of 490 pM for KU-1, 340 pM for NBT-2 and 103 pM for KK cells. With in situ RT-PCR, the tumour cells of 6 out of 26 primary bladder tumour specimens (23.1%) presented positive G-CSFR mRNA signals. Thus, in this study, G-CSFR expression was frequently observed on bladder cancer cells. Therefore, the clinical use of G-CSF for patients with bladder cancer should be selected with great care.

Carcinoma, Transitional Cell↗
PubMed1997

Phase I study of sequentially administered topoisomerase I inhibitor (irinotecan) and topoisomerase II inhibitor (etoposide) for metastatic non-small-cell lung cancer.

We conducted a phase I study of irinotecan (CPT-11) and etoposide (VP-16) given sequentially to untreated patients with metastatic non-small-cell lung cancer. Arm A: CPT-11 was given over 90 min on days 1-3 and VP-16 was given over 60 min on days 4-6. Arm B: VP-16 was given on days 1-3 and CPT-11 on days 4-6. G-CSF was given to all patients daily on days 7-17. Twenty-seven patients were entered randomly at the two arms. The major dose-limiting toxicities in arms A and B were granulocytopenia and diarrhoea. Transient elevations of transaminases and bilirubin were observed in both arms. The degree of the toxicities did not differ between the two arms. The maximum tolerated doses (MTDs) were 60 mg m-2 CPT-11 and 60 mg m-2 VP-16 in both arms. Of the 13 patients who received more than two cycles, two out of five achieved partial response (PR) at the first level of arm A and one out of four achieved PR at the second level of arm B. We conclude that these schedules of sequential CPT-11 and VP-16 administration were inappropriate because of severe toxicities.

Adult↗
PubMed1997

Modulation of Fas-mediated apoptosis of human thyroid epithelial cells by IgG from patients with Graves' disease (GD) and idiopathic myxoedema.

The expression of two autoimmune thyroid diseases. GD and idiopathic myxoedema, is associated with antibodies to the thyroid-stimulating hormone (TSH) receptor. Thyroid stimulating antibodies (TSAb) in GD are TSH agonists and cause hyperthyroidism as well as goitre, whereas thyroid stimulation blocking antibodies (TSBAb) in idiopathic myxoedema are TSH antagonists and cause hypothyroidism and thyroid atrophy. We investigated the effect of antibodies to TSH receptor on Fas-mediated apoptosis of thyroid epithelial cells (thyrocytes). Human IgG was isolated from healthy donors, patients with GD and idiopathic myxoedema. Human thyrocytes were obtained from surgical specimens. Thyrocytes were cultured in the presence or absence of human IgG with or without interferon-gamma (IFN-gamma) or IL-1beta for a specified time. After incubation, we examined the level of cAMP in cultured supernatants and both Fas and Bcl-2 expression on thyrocytes. In addition, we examined anti-Fas-mediated apoptosis of thyrocytes. Fas expression on thyrocytes was significantly down-regulated by Graves' IgG and TSH, although idiopathic myxoedema IgG did not affect Fas expression on thyrocytes. Idiopathic myxoedema IgG abrogated the effect of TSH on both cAMP production and inhibition of Fas expression on thyrocytes. Treatment of thyrocytes with IL-1beta or IFN-gamma caused a marked augmentation of Fas expression on thyrocytes. The increase of Fas expression of thyrocytes induced by IL-1beta or IFN-gamma was significantly suppressed in the presence of TSH or Graves' IgG. Anti-Fas-induced apoptosis of thyrocytes was observed in thyrocytes treated with IL-1beta or IFN-gamma, but was markedly inhibited in the presence of TSH or Graves' IgG. Furthermore, idiopathic myxoedema IgG abrogated most of the inhibitory effect of TSH on Fas-mediated apoptosis of thyrocytes treated with IL-1beta or IFN-gamma. Bcl-2 expression of thyrocytes did not change after stimulation with TSH, Graves' IgG, idiopathic myxoedema IgG, IL-1beta or IFN-gamma. These results suggest that TSAb found in Graves' patients may be potentially involved in the development of goitre by inhibition of Fas-mediated apoptosis of thyrocytes. In addition, TSBAb inhibit the action of TSH and increase the sensitivity toward Fas-mediated apoptosis of thyrocytes, inducing thyroid atrophy seen in patients with idiopathic myxoedema.

Apoptosis↗
PubMed1997

Effects of rapamycin on apoptosis of rheumatoid synovial cells.

In the present study, we investigated the effects of an immunosuppressant, rapamycin, on bcl-2 expression and the susceptibility of human rheumatoid synovial fibroblasts to Fas-mediated apoptosis. Rapamycin treatment down-regulated bcl-2 expression on rheumatoid synovial cells in a dose-dependent manner. In contrast, Fas antigen expression was not influenced by rapamycin treatment. Rapamycin treatment also enhanced the susceptibility of rheumatoid synovial cells to anti-Fas monoclonal antibody-mediated apoptosis. Our results suggest that rapamycin augments the sensitivity of rheumatoid synovial fibroblasts to apoptosis by down-regulating bcl-2 expression. This pharmacological alteration of sensitivity to apoptosis in the rheumatoid synovium may represent a new therapeutic approach for rheumatoid arthritis.

Adult↗
PubMed1997

Inhibitory effects of interleukin-10 on synovial cells of rheumatoid arthritis.

This paper describes the immunoregulatory effects of interleukin-10 (IL-10) on synovial cells in vitro. Synovial cells were cultured with IL-10 in the presence or absence of various cytokines. Following incubation, the costimulatory molecule expression on synovial cells and cytokine production in culture supernatants were analysed by an indirect immunofluorescence method and enzyme-linked immunosorbent assay, respectively. We also examined the effect of IL-10 on the function of synovial cells as antigen-presenting cells (APC). Synovial cells spontaneously express several kinds of costimulatory molecule and produce various kinds of cytokines. Stimulation of synovial cells with interferon-gamma (IFN-gamma), IL-1 beta, or 12-O-tetradecanoyl phorbol 13-acetate (TPA) markedly enhanced the expression of costimulatory molecules and cytokine production of these cells. Both spontaneous and up-regulated costimulatory molecule expression and cytokine production were significantly suppressed by the addition of IL-10. Autologous T-cell proliferation was stimulated by purified protein derivative (PPD) in IFN-gamma-treated synovial cells and treatment of these synovial cells with IL-10 also suppressed T-cell proliferation. Our results suggest that IL-10 has an inhibitory effect on synovial cells and is an important immunoregulatory component of the cytokine network in rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1997

Sensitivity of rat cortical neurons in distinguishing taste qualities by individual and correlative activities.

To examine the possibility that different taste qualities are represented by the correlative activity of cortical gustatory neurons, we made simultaneous recordings of neuron pairs during application of four basic tastes into the oral cavity of anesthetized rats and the following observations were made: (i) in 30 of 67 pairs of taste responsive neurons, peaks (troughs in a few cases) were produced in the cross-correlograms (CCs) during stimulation with some tastants; (ii) the correlative discharges occupied 6-8% of the total spikes discharged by individual neurons during taste stimulation and occurred, in a considerable number of cases, even during stimulation with tastants to which one or both of the component neurons of a pair were apparently non-responding (often sucrose and quinine); (iii) the number of tastants to which a neuron pair responded with a significant correlative activity was often greater than the number of tastants to which the component neurons of the same pair responded with significant changes in discharge rate; (iv) there was no significant difference between the correlative (formation of peaks or troughs in the CC) and individual (change in discharge rate of individual neurons) ways of coding in the sensitivity to distinguish between two taste qualities ranked to be adjacent on the basis of the number of spikes composing the response; and (v) the peaks or troughs appearing in two CCs during stimulations with two kinds of tastants were compared with regard to overlapping of their delay ranges and widths. The spikes in the non-overlapping portion of each peak (suppressed spike number in the case of troughs) are supposed to be able to contribute to two-taste discrimination: the correlated discharges occurring with a delay time that corresponds to the overlapping portion can in no way be judged differently, but the spikes falling in the non-overlapping portion may contribute to the differentiation. The ratio of the non-overlapping portion to the entire peak (or trough) was 0.35 on average. It is concluded that temporal coding of taste qualities seems to operate effectively in the gustatory cortex.

Animals↗
PubMed1997

High prevalence of Sjögren's syndrome in patients with HTLV-I associated myelopathy.

OBJECTIVE: A high seroprevalence of HTLV-I in female Sjögren's syndrome (SS) patients has been reported in Nagasaki, Japan, an area that is heavily endemic for HTLV-I infection. Salivary IgA class antibodies to HTLV-I were common among HTLV-I seropositive patients with SS. This study was undertaken to elucidate the pathogenesis of SS caused by HTLV-I infection. METHODS: The clinical features and histological findings of SS and the prevalence of serum autoantibodies in 10 patients with HTLV-I associated myelopathy (HAM) who were consecutively admitted into Nagasaki University School of Medicine, were compared with those of 20 HTLV-I seropositive and 20 HTLV-I seronegative patients with SS. RESULTS: Ocular and oral manifestations of SS were commonly detected in HAM patients. These patients also had extraglandular manifestations including recurrent uveitis, arthropathy, interstitial pneumonitis, Raynaud's phenomenon, and inflammatory bowel disease. All patients with HAM histologically showed a mononuclear cell infiltration in the labial salivary glands. Six of 10 patients had a mononuclear cell infiltration with a focus score of 1 or greater. According to the preliminary criteria for SS proposed by the European Community, definitive SS was diagnosed in six patients and probable SS in two patients. Serum gamma globulin and IgG values were increased in HAM patients. Patients with HAM had lower prevalence of rheumatoid factor, antinuclear antibody, and anti-SS-A (Ro) antibody than those of HTLV-I seropositive and HTLV-I seronegative SS patients. However, there was no significant difference in the prevalence of these antibodies among HAM patients with definitive SS, HTLV-I seropositive and HTLV-I seronegative SS patients. The CD3+CD4+ T cells preferentially infiltrated into the salivary glands in HAM patients as well as the salivary glands of patients with HTLV-I seropositive and seronegative patients. It seems probable that peripheral blood mononuclear cells from HAM patients preferentially infiltrated into the salivary glands, and that these cells produced the autoantibodies as well as anti-HTLV-I antibody. CONCLUSION: The results strongly support the idea that HTLV-I is involved in the pathogenesis of the disease in a subset of patients with SS in endemic areas.

Adult↗
PubMed1997

Fas and Fas ligand interaction is necessary for human osteoblast apoptosis.

We investigated the cellular and humoral interactions between peripheral blood mononuclear cells (PBMCs) and human osteoblasts, leading to apoptosis of osteoblasts. Human osteoblastic cell line MG63 and human primary osteoblast-like cells obtained from biopsy specimens were used in this study. PBMCs were isolated from healthy donors and cultured with or without stimulation by recombinant interleukin-2 followed by 12-o-tetradecanoylphorbol 13-acetate with ionomycin. Fas was functionally expressed on MG63 and primary osteoblast-like cells. Activated PBMCs expressed Fas ligand (FasL) strongly on their surface and killed MG63 and primary osteoblast-like cells. Cultured supernatants of activated PBMCs also induced apoptotic cell death of MG63 and primary osteoblast-like cells. In contrast, both unstimulated PBMCs and cultured supernatants of unstimulated PBMCs did not induce apoptosis of these cells. Furthermore, the cytotoxic effect and induction of apoptosis against MG63 and primary osteoblast-like cells by activated PBMCs and cultured supernatants were inhibited significantly by human Fas chimeric protein. Our data showed that human osteoblasts expressed Fas fuctionally and both membrane-type and soluble form FasL from activated PBMCs induced apoptosis of these cells, providing the one possible mechanism of bone loss in inflammatory diseases such as rheumatoid arthritis.

Antigens, Surface↗
PubMed1997

Signal transduction of granulocyte macrophage-colony stimulating factor in a human endothelium-derived cell line.

Granulocyte macrophage-colony stimulating factor (GM-CSF) regulates the growth and differentiation of hematopoietic cells and is also involved in angiogenesis. The induction of protein tyrosine phosphorylation is critical for cytokines and growth factor-mediated signal transduction. The protein tyrosine kinase (PTK), JAK2 is involved in signaling through a number of cytokine receptors, including GM-CSF receptors. In the present study, we investigated the effect of GM-CSF on the cell cycle and protein tyrosine phosphorylation in a human endothelial cell-derived cell line, EA.hy 926 cells. GM-CSF induced the cell cycle progression and tyrosine phosphorylation of cellular proteins including JAK2 kinase in EA.hy 926 cells. Herbimycin A, a PTK inhibitor, completely blocked the GM-CSF-induced cell cycle progression, protein tyrosine phosphorylation and JAK2 kinase activation in EA.hy 926 cells. Our results demonstrate that protein tyrosine phosphorylation and JAK2 kinase activation are closely related to the GM-CSF-mediated signal transduction and growth in vascular endothelial cells, and suggest the efficacy of herbimycin A in controlling angiogenesis.

Benzoquinones↗
PubMed1997

Heightened transmigrating activity of CD4-positive T cells through reconstituted basement membrane in patients with human T-lymphotropic virus type I-associated myelopathy.

We investigated the transmigrating activity of peripheral blood T cells of patients with human T-lymphotropic virus type I-associated myelopathy (HAM) through reconstituted basement membrane. The transmigrating activity of CD4+ T cells of HAM patients was increased significantly in comparison to that of anti-HTLV-I-seropositive carriers and HTLV-I-seronegative controls. However, the migrating activity of CD8+ T cells was not significantly different in HAM patients and controls. The activity of aminopeptidase-N in peripheral blood T cells of HAM patients also was increased significantly, as compared to that of controls. In addition, HTLV-I proviral load in transmigrating CD4+ T cells of HAM patients was increased significantly (two- to eight-fold), compared to that in nontransmigrating CD4+ cells. By contrast, no significant difference in HTLV-I proviral load was found between transmigrating and nontransmigrating CD4+ cells of HTLV-I-seropositive carriers, although copy numbers of HTLV-I proviral load were very low in them. The heightened transmigrating activity of CD4+ cells from HAM patients through reconstituted basement membrane is based on the increased activity of aminopeptidase-N. Collectively, these findings suggest that HTLV-I-infected CD4+ T cells play an important role in the early stage of the pathogenesis of HAM.

Adult↗
PubMed1997

Premature fat deposition in the salivary glands associated with Sjögren syndrome: MR and CT evidence.

PURPOSE: To investigate abnormal fat deposition in the major salivary glands associated with Sjögren syndrome. METHODS: We analyzed the fat deposition in the parotid and submandibular glands of 33 patients with Sjögren syndrome by using short-inversion-time inversion recovery (STIR) and fat-saturation MR sequences and CT values. RESULTS: All three in vivo techniques substantially confirmed premature deposition of fat in the major salivary glands in association with Sjögren syndrome. Furthermore, this change was characteristic of Sjögren syndrome, and the severity of fat deposition correlated well with the impaired rates of salivary flow in these patients. CONCLUSION: Monitoring of fat deposition might be useful for diagnosing Sjögren syndrome and assessing its progress in patients whose clinical and serologic findings are suggestive of the disease.

Adult↗
PubMed1997

Serum levels of pro-gastrin-releasing peptide for follow-up of patients with small cell lung cancer.

To assess the clinical usefulness of serum pro-gastrin-releasing peptide (Pro-GRP) as a tumor marker for small cell lung carcinoma (SCLC), we measured serum levels of Pro-GRP with a newly developed ELISA and measured serum levels of neuron-specific enolase (NSE) in 44 patients with untreated SCLC and 77 patients with untreated non-SCLC. We prospectively measured serum levels of Pro-GRP and NSE in SCLC patients after initial treatment until relapse. The sensitivity (70%) and specificity (91%) of Pro-GRP were similar to those of NSE (70 and 86%). Thirty-nine % of patients who had a partial response still had elevated serum levels of Pro-GRP at the time of restaging after initial treatment. In follow-up study, 94% of patients had elevated serum levels of Pro-GRP again at the time of relapse, whereas 37% of patients showed elevated levels of NSE. Levels of Pro-GRP increased a median of 35 (-95 to 151) days before clinical evidence of relapse was detected with successive physical examinations and imaging studies, whereas levels of NSE increased 20 (-85 to 124) days after relapse was detected (P < 0.05). Pro-GRP was helpful as a diagnostic aid and a marker for therapeutic effect and relapse in patients with SCLC, supplemented to serum NSE.

Adult↗
PubMed1996

Correlated discharges of two neurons in rat gustatory cortex during gustatory stimulation.

During application of tastants into the oral cavity correlated activities were observed in 27 of 64 neuron pairs recorded simultaneously in the gustatory cortex of anesthetized rats. The mean frequency of correlated discharges as assessed from the size of the peak appearing in the cross-correlogram was lower (0.2-0.33 spikes/s) and the mean width of the peaks was wider (8 ms) as compared to those reported in the gustatory relay stations in the brainstem. In a few cases troughs were formed or peaks appeared with a long delay.

Animals↗
PubMed1996

Fas antigen expression on synovial cells was down-regulated by interleukin 1 beta.

Recent reports revealed that Fas antigen is functionally expressed on human synovial cells and apoptosis can be induced in these cells by anti-Fas antibody. We examined the effect of interleukin 1 beta (IL-1 beta) on Fas antigen-mediated apoptosis on human synovial cells in vitro. Using flowcytometric analysis, IL-1 beta inhibited Fas antigen expression on synovial cells in a dose-dependent fashion. No significant difference of Fas antigen gene expression between IL-1 beta-treated and untreated synovial cells was observed by RT-PCR analysis, suggesting that the inhibitory effect of Fas antigen expression by IL-1 beta is at posttranscriptional level. Apoptosis of synovial cells was easily induced by treatment of these cells with anti-Fas antibody. In contrast, pretreatment of synovial cells with IL-1 beta protected these cells against Fas antigen-mediated apoptosis. The expression of bcl-2 on synovial cells, known to interfere with the apoptotic process mediated by the Fas antigen, was not influenced by IL-1 beta. Our results suggest that IL-1 beta inhibits Fas antigen-mediated apoptosis of synovial cells and may perpetuate the hyperplasia of the synovium in patients with rheumatoid arthritis.

Apoptosis↗