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Biomedical subjects

H Yamauchi

Publications and source records attributed to H Yamauchi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Levels of interleukin-18 and its binding inhibitors in the blood circulation of patients with adult-onset Still's disease.

OBJECTIVE: Interleukin-18 (IL-18) is a proinflammatory cytokine that is involved in immunologically mediated tissue damage, but its bioactivity is regulated in vivo by its soluble decoy receptor, IL-18 binding protein (IL-18BP). This study was undertaken to determine levels of IL-18 and IL-18 binding inhibition in the blood of patients with adult-onset Still's disease (ASD). METHODS: Serum concentrations of IL-18 in ASD patients were compared by enzyme-linked immunosorbent assay (ELISA) with those in patients with other systemic rheumatic diseases and healthy controls. The biologically active mature protein of IL-18 was detected by Western blot analysis with anti-IL-18 antibody and its induction of interferon-gamma (IFNgamma) secretion from IL-18-responding human myelomonocytic KG-1 cells. The inhibitory activity on IL-18 binding to its receptor was determined by 125I-IL-18 binding inhibition assay using the Chinese hamster ovary cell line transfected with a murine IL-18 receptor (CHO-K1/mIL-18R). RESULTS: Concentrations of serum IL-18 were extremely elevated in patients with active ASD compared with those in patients with rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, polymyositis/dermatomyositis, Sjogren's syndrome, or healthy individuals. Levels of IL-18 were found to correlate with serum ferritin values and disease severity in ASD. Western blot analysis revealed that serum samples from patients with active ASD contained an 18-kd polypeptide of IL-18, corresponding in size to the mature form. Accordingly, the samples were able to induce IFNgamma secretion from KG-1 cells, which was largely abolished by neutralizing anti-IL-18 antibody. However, the level of IL-18 bioactivity was more than 10-fold weaker than the concentration of IL-18 protein measured by ELISA. Serum samples from patients with active ASD showed an inhibitory effect on the binding of 125I-IL-18 to CHO-K1/mIL-18R cells, and this activity was associated with elevation of IL-18. CONCLUSION: These data indicate that systemic overproduction of IL-18 may be closely related to the pathogenesis of ASD, despite the restriction on its inflammatory activity by IL-18 binding inhibitors such as IL-18BP. The disease activity appears to be determined on the basis of the relative levels of IL-18 and its specific inhibitors.

Adult↗
PubMed2001

Characterization of a novel gene, sperm-tail-associated protein (Stap), in mouse post-meiotic testicular germ cells.

During mammalian spermatogenesis, many specific molecules show the dynamics of expression and elimination, corresponding with the morphological differentiation of germ cells. We have isolated a novel cDNA designated F77 from mouse testis by cDNA subtractive hybridization between normal and sterile mice, using the C57BL/6 congenic strain for the hybrid sterilityhyphen;3 lpar;Hsthyphen;3rpar; allele from Mus spretus. The full-length F77 mRNA was 3.4 kb and showed significant nonmatching with entries in the databases. F77 was mapped at a proximal position between D8Mit212 and D8Mit138 on mouse chromosome 8, in which no corresponding genes related to its nucleotide sequence were found. F77 mRNA was not detected in any other organs except the testis of adult fertile mice. F77 protein was only seen in normal adult testis and epididymis. In contrast to normal C57BL/6 mice, F77 mRNA and protein were not seen in germ cell-deficient Kit(W)/Kit(Wv) mice. By in situ hybridization, F77 mRNA was detected mainly at round spermatids in the sexually mature testis, and immunohistochemical analysis revealed that F77 protein was located at the tail of elongated spermatids. We are proposing the name, sperm-tail-associated protein (Stap), for the gene encoding F77 cDNA. Mol. Reprod. Dev. 59: 350-358, 2001.

Amino Acid Sequence↗
PubMed2001

The Role of c-erbB-2 as a predictive factor in breast cancer.

Most women diagnosed with primary invasive breast cancer are potential candidates to receive adjuvant systemic treatment. Tumor markers that predict the likelihood of response to therapy might help select optimal treatment for individual patients. Of these, c-erbB-2 is the most promising marker. In the past 15 years, over 200 reports related to c-erbB-2 and breast cancer have been published. However, its clinical role remains unclear. c-erbB-2 might serve as either a pure prognostic factor, with no association with therapy, or as a predictive factor of benefit from specific types of systemic treatments. A recent overview suggested that c-erbB-2 is only a weak prognostic factor. A review of the literature suggests that c-erbB-2 overexpression might predict for relative, but not absolute, resistance to endocrine therapy in estrogen receptor-positive women. When adjuvant chemotherapy is indicated, c-erbB-2 positive patients may receive more benefit from anthracycline-containing regimens than alkylating agents. However, if anthracyclines are contraindicated, women with c-erbB-2 positive tumor do derive benefit from alkylating agents. Importantly, c-erbB-2 status appears critical for selecting patients who should receive trastuzumab. Well-designed prospective randomized clinical trials or formal meta-analysis will help to establish the predictive role of c-erbB-2.

Antibodies, Monoclonal↗
PubMed2001

Expression of the Gfi-1 gene in HTLV-1-transformed T cells.

Human T-cell leukemia virus type I (HTLV-I) is the causative agent of adult T-cell leukemia/lymphoma (ATLL) and immortalizes human T cells interleukin-2 (IL-2)-dependently in vitro. Protracted culture of HTLV-I-infected T cells enables them to grow IL-2-independently. Although acquisition of IL-2-independent growth has been correlated with activation of signal transducers and activators of transcription (STATs), the precise mechanism of IL-2-independent growth is unknown. We found that expression of the Gfi-1 (growth factor independence-1) gene was elevated in most HTLV-I-transformed IL-2-independent cell lines but in few HTLV-I-infected IL-2-dependent cell lines. We also found elevated expression of Gfi-1 in fresh leukemic cells of ATLL patients. Although expression of Gfi-1 is correlated with activation of STAT3, induction of the dominant negative form of STAT3 in the HUT102 cell line does not alter the level of Gfi-1 expression. Furthermore, MT2 cells treated with Gfi-1 antisense oligonucleotide had reduced [3H]thymidine uptake compared with MT2 cells treated with Gfi-1 sense oligonucleotide. These findings indicate that Gfi-1 activation is involved in the IL-2-independent growth of HTLV-I-transformed T cells in vitro and in the development of ATLL in vivo, but is not induced by STAT activation.

Adult↗
PubMed2001

The platelet-sparing effect of paclitaxel is not related to changes in the pharmacokinetics of carboplatin.

PURPOSE: To determine whether the platelet-sparing effect of paclitaxel is related to changes in pharmacology of carboplatin. METHODS: A group of 32 patients with epithelial ovarian cancer were treated with intraperitoneal (i.p.) carboplatin-based chemotherapy with carboplatin alone or in combination with cyclophosphamide or paclitaxel, and the relationship between the pharmacology of serum platinum and thrombocytopenia was examined. The target AUC of i.p. carboplatin was 6.5 mg min/ml. Cyclophosphamide was administered intravenously at 400 mg/m2 after i.p. carboplatin and paclitaxel at 175 mg/m2 was given before i.p. carboplatin. RESULTS: Ten patients received i.p. carboplatin alone, 10 received cyclophosphamide and 12 received paclitaxel. The ages of the patients, body surface area, serum creatinine, platelet count before chemotherapy, and the total dose of carboplatin in each patient were similar in all groups. The measured AUC, Cmax, T 1/2, and MRT were similar in these groups. The nadir platelet counts were significantly higher (P = 0.0018) in patients treated with i.p. carboplatin with paclitaxel (12.1 +/- 4.3 x 10(4)/mm3) compared with carboplatin alone (5.2 +/- 3.3 x 10(4)/mm3) or with cyclophosphamide (5.2 +/- 4.8 x 10(4)/mm3). The percentage decrease in platelet counts was significantly lower (62.5 +/- 18.2%) in patients treated with paclitaxel than in the other two groups (81.5 +/- 12.6% carboplatin alone, 88.7 +/- 7.9% with cyclophosphamide). CONCLUSION: The addition of paclitaxel or cyclophosphamide to i.p. carboplatin did not alter the pharmacology of serum platinum. Thrombocytopenia was significantly less in patients treated with carboplatin in combination with paclitaxel. The platelet-sparing effect of paclitaxel is not related to changes in the pharmacology of carboplatin.

Age Factors↗
PubMed2001

Japanese spotted fever associated with multiorgan failure.

A 49-year-old man was admitted to our hospital, with a diagnosis of multiple organ failure, on June 10, 2000. Physical examination revealed high fever, generalized maculopapular erythema, and an eschar on his lower leg. Laboratory findings revealed severe renal and liver dysfunction, disseminated intravascular coagulation (DIC), and markedly elevated soluble interleukin 2-receptor (sIL2-R) level (>10 000 U/ml). Administration of minocycline was started immediately, with a diagnosis of rickettsial infection. Simultaneously, anti-thrombin III and heparin were started to treat the DIC, and hemodialysis was also initiated. However, the day after admission, his consciousness level lapsed, to the level of coma, and blood pressure was less than 60 mmHg, indicating shock. Therefore, 500 mg of methylprednisolone was administered once; as a result, rapid pyretolysis and improvement of consciousness disturbance were achieved. Laboratory data indicative of inflammation gradually improved after a few days. Hemodialysis was required ten times. During the recovery period, the level of specific IgM antibody against Rickettsia japonica increased to x2560, and he was diagnosed as having Japanese spotted fever. On July 11, he was discharged without sequelae. The course in our patient was very severe, and treatment with minocycline alone may have resulted in a fatal outcome. The level of sIL2-R, which is produced by activated lymphocytes, was markedly increased. Therefore, markedly elevated lymphocyte activation and hypercytokinemia may have been present on admission. The short-term steroid therapy may have been effective in inhibiting the excessive activation of lymphocytes in the critical stage. In the severe form of Japanese spotted fever with organ failure, combination therapy with minocycline and short-term steroids may be very useful.

Anti-Bacterial Agents↗
PubMed2001

Reduction in recalcitrant pulmonary hypertension after operation for atrial septal defect.

We present the case of a patient with atrial septal defect and severe pulmonary hypertension with pulmonary artery peak pressure greater than 110 mm Hg. Open lung biopsy was done prior to the corrective operation, and pathological findings in the small pulmonary arteries included "musculoelastosis" and complete occlusion of 70% of these small arteries and arterioles. The atrial septal defect was closed, and long-term oral prostacyclin therapy was initiated. Pulmonary artery peak pressure decreased to 65 mm Hg 2 years after the operation. This case demonstrates that in a patient with 70% complete occlusion of small pulmonary arteries and arterioles resulting from "musculoelastosis," not only is surgical intervention possible but also pulmonary artery pressure decreases in the long term after operation.

Adult↗
PubMed2001

Two novel insect defensins from larvae of the cupreous chafer, Anomala cuprea: purification, amino acid sequences and antibacterial activity.

A humoral immune response in larvae of the coleopteran insect, Anomala cuprea has been examined for exploring the molecular basis of host-pathogen interactions. The antibacterial activity against the Gram-positive strain, Micrococcus luteus was detected at a low level in absence of injection. The activity increased strikingly in the hemolymph of the larvae challenged with Escherichia coli, showing the fluctuating profile through a time course, which consists of the static induction phase, the production phase rising to a maximum level, and the reduction phase extending over a long duration. Two peptides were purified and characterized by reverse-phase HPLC, Edman degradation and mass spectrometry. They were isoforms, composed of similar sequences with two amino acid substitutions in 43 residues, and novel members of the insect defensins, cysteine-rich antibacterial peptides. Anomala defensins A and B showed potent activity against Gram-positive bacteria, with slight differences in activity against a few strains of tested bacteria. Anomala defensin B was active at high concentration of 40 microM against the Gram-negative strain, Xenorhabdus japonicus, a pathogen toward the host, A. cuprea larvae.

Amino Acid Sequence↗
PubMed2001

Interferon gamma induction in human melanoma cell/allogeneic leukocyte co-cultures is enhanced by interleukin 18 but drug resistant melanoma cells are poorer inducers of IFN-gamma.

Human melanoma Colo 679 cells were made resistant to doxorubicin (adriamycin, ADM) by continuous exposure to ascending concentrations of the drug and Colo/ADM80; a variant which grew continuously in the presence of 80 ng/ml of ADM was thus established. Human peripheral blood mononuclear cells (PBMC) produced interferon gamma (IFN-gamma) when cultured with mitomycin C (MMC)-treated parental Colo 679 cells. The synthesis of IFN-gamma was synergistically enhanced by adding interleukin-18 (IL-18) and this was IL-12-dependent because a neutralizing antibody against IL-12 almost completely inhibited IFN-gamma production while control antibodies (Abs) were inactive. The cellular sources of IFN-gamma were found to be B cells, CD8+ T cells and CD4+ T cells as revealed by flow cytometry after double staining for surface antigens and staining for intracellular IFN-gamma. Interestingly, the resistant cell line induced much less IFN-gamma production than the parental cell line under the same co-culture conditions; however, IL-18 could still enhance the production of IFN-gamma. In conclusion, our study shows that acquired resistance to anti-cancer agents can also reduce immune responses to cancer cells. However, the immunostimulatory cytokine IL-18 could still enhance IFN-gamma production in drug resistant tumor cell-PBMC cultures indicating that such immunostimulatory agents could still be beneficial in immunotherapy for patients with recurrent drug resistant tumors.

Coculture Techniques↗
PubMed2001

Engagement of the CrkL adaptor in interferon alpha signalling in BCR-ABL-expressing cells.

Interferon alpha (IFNalpha) has significant clinical activity in the treatment of patients with chronic myelogenous leukaemia (CML), but the mechanisms of its selective efficacy in the treatment of the disease are unknown. The CrkL adaptor protein interacts directly with the BCR-ABL fusion protein that causes the malignant transformation and is constitutively phosphorylated in BCR-ABL-expressing cells. In the present study, we provide evidence that CrkL was engaged in IFNalpha-signalling in the CML-derived KT-1 cell line, which expresses BCR-ABL and is sensitive to the growth inhibitory effects of IFNalpha. CrkL is constitutively associated with BCR-ABL in these cells and treatment with IFNalpha had no effect on the BCR-ABL/CrkL interaction. After IFNalpha stimulation, CrkL associated with Stat5, which also underwent phosphorylation in an IFNalpha-dependent manner. The interaction of CrkL with Stat5 was facilitated by the function of both the SH2 and the N-terminus SH3 domains of CrkL. The resulting CrkL-Stat5 complex translocated to the nucleus and could be detected in gel shift assays using elements derived from either the beta-casein promoter or the promoter of the PML gene, an IFNalpha-inducible gene that mediates growth inhibitory responses. In addition to its interaction with Stat5, CrkL interacts with C3G in KT-1 cells and such an interaction regulates the downstream activation of the small GTPase Rap1, which also mediates inhibition of cell proliferation. Thus, despite its engagement by BCR-ABL in CML-derived cells, CrkL mediates activation of downstream signalling pathways in response to the activated type I IFN receptor and such signals may contribute to the generation of the anti-proliferative effects of IFNalpha in CML.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Intestinal tissue oxygenation and tumor necrosis factor-alpha release during systemic blood flow changes in pigs with left ventricular assist devices.

We previously demonstrated that tumor necrosis factor-alpha (TNF-alpha) increased following a reduction in systemic blood flow to 60% or less of the original cardiac output using a left ventricular assist device (LVAD). The aim of this study was to investigate the effect of reducing systemic blood flow on tissue oxygenation in the gastrointestinal tract (GIT) and the consequences of this on TNF-alpha release. LVADs were implanted in 9 pigs. The aorta was clamped, and thus the LVAD flow represented the entire systemic blood flow. Plasma TNF-alpha of the superior mesenteric vein was measured at baseline and during systemic blood flow changes. Simultaneously, pH, lactate, oxygen delivery index (DO(2)I), oxygen consumption index (VO(2)I), and oxygen extraction (O(2)ER) in the GIT were measured. The pH decreased and the lactate level increased significantly (p < 0.05) at a systemic blood flow of 50% or less. The VO(2)I was positively correlated with DO(2)I. The O(2)ER increased significantly (p < 0.05) with reductions in systemic blood flow to 30% or less. There was a significant (p < 0.01) correlation between TNF-alpha and O(2)ER at levels higher than 55%. These data demonstrate that the GIT oxygenation is inadequate with a reduction in systemic blood flow to 50% and that GIT oxygenation becomes critical at a reduction of 30%. During LVAD weaning, careful attention must be given to the GIT. The pH and lactate may be good markers of the adequacy of tissue oxygenation in the GIT.

Animals↗
PubMed2001

Effect of variation in systemic blood flow on plasma TNF-alpha in a pig model with left ventricular assist device.

Tumor necrosis factor-alpha (TNF-alpha) release has been implicated in a sepsis-like syndrome following cardiopulmonary bypass (CPB). This also may be important in patients who have had a left ventricular assist device (LVAD) implanted. This report investigates the effect of reducing systemic blood flow on hemodynamic response, mixed venous oxygen saturation (SvO(2)), and the release of TNF-alpha. LVADs were implanted in 9 pigs. The aorta was clamped, and thus the LVAD flow represented the entire systemic blood flow. Plasma TNF-alpha in the femoral artery (FA) and superior mesenteric vein (SMV) was measured at baseline and following systemic blood flow changes. Simultaneously, hemodynamic parameters and oxygen saturation in the pulmonary artery (SvO(2)) were measured. Following reductions in systemic blood flow, plasma TNF-alpha increased gradually to a maximum level at a systemic blood flow of 20%. There was no significant difference between TNF-alpha levels in the SMV and the FA. There was a significant (p < 0.05) correlation between cardiac index, stroke volume index, and TNF-alpha. The SvO(2) decreased significantly (p < 0.05) at a systemic blood flow of 30 and 20%. A rise in TNF-alpha occurred when the SvO(2) was less than 75%. The data demonstrate that a reduction in systemic blood flow causes an increase in plasma TNF-alpha. This can lead to the development of a sepsis-like syndrome in a group of patients who already are hemodynamically compromised. While weaning short-term LVAD support, rapid diminution of the cardiac output and the pump flow must be avoided.

Analysis of Variance↗
PubMed2001

Will accident reports filed in hospitals in Japan be used in the future as evidence in malpractice lawsuits?

A major drawback of submission of so-called incident reports for medical institutions is that such reports may be able to be obtained on request by patients and to be used as evidence in malpractice lawsuits. In Japan, there are no established rules concerning the use of accident reports in medical lawsuits. More debate is needed for voluntary report systems to become established in medical institutions throughout Japan.

Disclosure↗