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Biomedical subjects

K Takeda

Publications and source records attributed to K Takeda.

At least 235 records · Page 13Linked to original sources
PubMed2000

Signal transducer and activator of transcription 6 is essential in the induction of contact hypersensitivity.

Contact hypersensitivity (CHS) is thought to be mainly associated with the activation of T helper type 1 (Th1) cells. However, there is also evidence that Th2 cells or Th2 cytokines play a role in the development of CHS. To analyze the functional contribution of Th2 cytokines interleukin (IL)-4 and IL-13, signal transducer and activator of transcription 6 (STAT6)-deficient (STAT6(-/)-) and wild-type (wt) control C57BL/6 mice were contact sensitized with 5% 2,4,6-trinitrochlorobenzene (TNCB), 0.5% 2,4-dinitrofluorobenzene, or 5% 4-ethoxyl methylene-2-phenyl-2-oxazolin-5-one, and any skin reactions were examined. Ear swelling was significantly reduced with a delayed peak response in STAT6(-/)- mice compared with wt mice.A histological analysis revealed that the infiltration of both eosinophils and neutrophils in the skin challenged after 24 h in STAT6(-/)- mice decreased substantially compared with that in wt mice. The expression of Th2 cytokines (IL-4, IL-5) in TNCB-challenged skin tissues and the supernatants from T cells stimulated by 2,4,6-trinitrobenzene sulfonate-modified spleen cells, as well as the immunoglobulin (Ig)E and IgG1 response after challenge, were also profoundly reduced in STAT6(-/)- mice, whereas the expression of interferon gamma was the same in STAT6(-/)- and wt mice after challenge. Furthermore, adoptive transfer experiments revealed that STAT6(-/)- mice induced CHS after injection of lymph node cells obtained from sensitized wt mice. Our data suggest that the STAT6 signal plays a critical role in the induction phase of CHS.

Animals↗
PubMed2000

Identification and localization of two brefeldin A-inhibited guanine nucleotide-exchange proteins for ADP-ribosylation factors in a macromolecular complex.

Two brefeldin A (BFA)-inhibited guanine nucleotide-exchange proteins for ADP-ribosylation factors, 200-kDa BIG1 and 190-kDa BIG2, were copurified from bovine brain cytosol associated with >670-kDa macromolecular complexes. When observed by immunofluorescence in HeLa S3 and HepG2 cells, endogenous BIG1 and coexpressed BIG2 were distributed in a punctate pattern throughout the cytosol, and also concentrated in the perinuclear region, where endogenous BIG1 and BIG2 each partially colocalized with Golgi-specific 58K protein and gamma-adaptin. On Western blot analysis, both BIG1 and BIG2 were clearly more abundant in the cytosol than in the microsomal fractions. After density gradient centrifugation of a microsomal fraction, BIG1 and BIG2 were recovered in the same fraction as beta-COP, a marker for Golgi membranes. When cytosol from HeLa S3 cells was subjected to gel filtration and fractions were analyzed by Western blotting, the largest percentages of both BIG1 and BIG2 were detected in fractions containing proteins with a molecular mass of >670 kDa. Western blotting using anti-peptide antibodies specific for BIG1 or BIG2 demonstrated that approximately 70% of BIG2 was immunoprecipitated along with 100% of BIG1 by the anti-BIG1 IgG, and approximately 75% of BIG1 was coprecipitated with 100% of BIG2 by the anti-BIG2 IgG. All observations were consistent with the conclusion that significant fractions of BIG1 and BIG2 exist as components of the same macromolecular complexes in bovine brain cytosol and are similarly localized in cultured cells.

ADP-Ribosylation Factors↗
PubMed2000

Force-length relationship in dogs as a measure of protective effect of imidapril on regional myocardial ischemia and reperfusion injury.

Our laboratory previously reported that the end-systolic force-length relationship of the left ventricle provides a better method of evaluating myocardial contractile properties than the left ventricular end-systolic pressure-volume relationship, because it avoids deficiencies of the latter parameter such as dependence of its slope (E(max)) on the volume intercept (V(0)). The slope (E(c)) of the left ventricular end-systolic force-length relationship represents the contractility of functioning myocardium, while its length intercept (L(0)) reflects the length of non-functioning myocardium. However, the effect of regional myocardial ischemia on these parameters, as evaluated by the force-length relationship, remains unknown. To clarify the effects of regional ischemia and angiotensin-converting enzyme inhibition on the myocardium during ischemia-reperfusion, the changes in E(c) and L(0) were determined in anesthetized open-chest dogs. (1) Control group (n=26): Before and after 15 min of complete coronary artery occlusion, as well as after 15 min of reperfusion, left ventricular pressure and volume were simultaneously recorded during inferior vena cava occlusion. The left ventricular force-length relationship was obtained from the pressure and volume of three cylindrical segments of the ventricle, and E(c) and L(0) were calculated. (2) Imidapril group (n=14): Imidaprilat (1 microg/kg/min) was continuously infused from 30 min before ischemia to the end of the experiment, and the same procedures were followed as in the control group. Fourteen out of the 26 dogs (54%) in the control group died of reperfusion-induced ventricular arrhythmias, while only two of the 14 dogs (14%) in the imidapril group did so (P<0.05). In the control group, E(c) was increased during ischemia and remained at the same level after reperfusion. However, E(c) was not altered in the imidapril group. Although L(0) was increased during ischemia and decreased after reperfusion in both groups, the percent increase of L(0) in the imidapril group was significantly smaller than in the control group (8% vs. 32%, P<0.05). With the improvement of these indices, the bradykinin concentration of coronary venous blood increased in the imidapril group (P<0.01). These findings suggest that regional myocardial ischemia increased the average contractility of overall functioning myocardium despite the increased non-functioning myocardium. Moreover, imidapril has a cardioprotective effect against ischemia-reperfusion injury by decreasing infarct size, and through the antiarrhythmic effect and the reversal of increased overall contractility.

Adrenergic beta-Antagonists↗
PubMed2000

Cloning and characterization of a novel adaptor protein, CIN85, that interacts with c-Cbl.

The c-Cbl protooncogene product is a prominent substrate of protein tyrosine kinases and is rapidly tyrosine-phosphorylated upon stimulation of a wide variety of cell-surface receptors. We have identified a novel c-Cbl-interacting protein termed CIN85 with a molecular mass of 85 kDa which shows similarity to adaptor proteins, CMS and CD2AP. CIN85 mRNA is expressed ubiquitously in normal human tissues and cancer cell lines analyzed. CIN85 was basally associated with c-Cbl. For interaction of CIN85 with c-Cbl, the second SH3 domain of CIN85 was shown to serve as a central player. The CIN85-c-Cbl association was enhanced shortly after stimulation of 293 cells with epidermal growth factor (EGF) and gradually diminished to a basal level, which correlated with a tyrosine phosphorylation level of c-Cbl. Our results suggest that CIN85 may play a specific role in the EGF receptor-mediated signaling cascade via its interaction with c-Cbl.

Adaptor Proteins, Signal Transducing↗
PubMed2000

CD27-mediated activation of murine NK cells.

CD27, a member of the TNF receptor superfamily, has been implicated in T cell activation, T cell development, and T cell-dependent Ab production by B cells. In the present study we examined the expression and function of CD27 on murine NK cells. Murine NK cells constitutively expressed CD27 on their surface. Stimulation with immobilized anti-CD27 mAb or murine CD27 ligand (CD70) transfectans solely could induce proliferation and IFN-gamma production of freshly isolated NK cells and enhanced the proliferation and IFN-gamma production of anti-NK1.1-sutimulated NK cells. Although NK cell cytotoxicity was not triggered by anti-CD27 mAb or against CD70 transfectants, prestimulation via CD27 enhanced the cytotoxic activity of NK cells in an IFN-gamma-dependent manner. These results suggest that CD27-mediated activation may be involved in the NK cell-mediated innate immunity against virus-infected or transformed cells expressing CD70.

Adjuvants, Immunologic↗
PubMed2000

Direct in vitro evidence and in vivo analysis of the antiangiogenesis effects of interleukin 12.

As an antitumor agent, interleukin-12 (IL-12) has been revealed to be a key regulator of the immune response, particularly that involving CTL and natural killer (NK) cells. We report herein the antiangiogenesis effect of IL-12 on human as well as murine tumors in NK-depleted severe-combined immunodeficient mice using fibroblasts genetically engineered to secrete this cytokine. Although the in vitro growth of tumor cells was not affected by the presence of IL-12, coinoculation of IL-12-secreting fibroblasts strongly inhibited tumor growth in immunodeficient mice. The neovascularization surrounding the tumor was remarkably inhibited in the area in which the IL-12-secreting fibroblasts were implanted, resulting in the suppression of tumor growth. Lectin staining in tumor sample sections also showed a significant reduction in the number of vessels. The RNA expression of IFN-gamma and its inducible antiangiogenic chemokine IFN gamma-inducible protein 10 was stimulated in endothelial cells cultured with IL-12. It was also found that IL-12 down-regulated the expression of the endothelial cell mitogens vascular endothelial growth factor and basic fibroblast growth factor. The antitumor effects of IL-12 were accompanied by interesting histological changes consisting of a high degree of keratinization and apoptosis and a decrease in the proliferation rate of human tumors and extensive necrosis in the murine ones.

3T3 Cells↗
PubMed2000

Similarities in function and gene structure of cytohesin-4 and cytohesin-1, guanine nucleotide-exchange proteins for ADP-ribosylation factors.

Activation of ADP-ribosylation factors (ARFs), approximately 20-kDa GTPases that are inactive in the GDP-bound form, depends on guanine nucleotide-exchange proteins (GEPs) to accelerate GTP binding. A novel ARF GEP, designated cytohesin-4, was cloned from a human brain cDNA library. Deduced amino acid sequence of the 47-kDa protein contains the same structural components present in cytohesin -1, -2, and -3, including an approximately 200-amino acid Sec7 domain with an approximately 100-residue pleckstrin homology domain near the C terminus. The Sec7 domain sequence is 77% identical to those of other cytohesins. Structures of the cytohesin-4 and cytohesin-1 genes were remarkably similar, except for an extra 3-base pair (GAG) exon present in cytohesin-1. Two mRNAs with and without the 3-base pair sequence were found in brain in different ratios for cytohesin-1, -2, and -3 but not cytohesin-4. Recombinant cytohesin-4 stimulated guanosine 5'-3-O-(thio)triphosphate binding by human ARF1 and ARF5 but not ARF6. Like other cytohesins and unlike the approximately 200-kDa ARF GEPs, it was not inhibited by brefeldin A. A cytohesin-4 mRNA of approximately 3.7 kilobases, abundant in leukocytes, was not detected in most tissues. Among separated populations of blood cells, approximately 90% of CD33(+) (monocytes), 80% of CD2(+) (NK/T), and 10-20% of CD19(+) (B) cells contained cytohesin-4 mRNA by in situ hybridization. Thus, in gene structure and brefeldin A-insensitive GEP activity, cytohesin-4 resembles other cytohesins, but its tissue distribution differs considerably, consistent with a different specific function.

ADP-Ribosylation Factors↗
PubMed2000

Critical contribution of OX40 ligand to T helper cell type 2 differentiation in experimental leishmaniasis.

Infection of inbred mouse strains with Leishmania major is a well characterized model for analysis of T helper (Th)1 and Th2 cell development in vivo. In this study, to address the role of costimulatory molecules CD27, CD30, 4-1BB, and OX40, which belong to the tumor necrosis factor receptor superfamily, in the development of Th1 and Th2 cells in vivo, we administered monoclonal antibody (mAb) against their ligands, CD70, CD30 ligand (L), 4-1BBL, and OX40L, to mice infected with L. major. Whereas anti-CD70, anti-CD30L, and anti-4-1BBL mAb exhibited no effect in either susceptible BALB/c or resistant C57BL/6 mice, the administration of anti-OX40L mAb abrogated progressive disease in BALB/c mice. Flow cytometric analysis indicated that OX40 was expressed on CD4(+) T cells and OX40L was expressed on CD11c(+) dendritic cells in the popliteal lymph nodes of L. major-infected BALB/c mice. In vitro stimulation of these CD4(+) T cells showed that anti-OX40L mAb treatment resulted in substantially reduced production of Th2 cytokines. Moreover, this change in cytokine levels was associated with reduced levels of anti-L. major immunoglobulin (Ig)G1 and serum IgE. These results indicate that anti-OX40L mAb abrogated progressive leishmaniasis in BALB/c mice by suppressing the development of Th2 responses, substantiating a critical role of OX40-OX40L interaction in Th2 development in vivo.

4-1BB Ligand↗
PubMed2000

Pulmonary hypertension associated with pulmonary occlusive vasculopathy after allogeneic bone marrow transplantation.

BACKGROUND: Pulmonary vasculature abnormalities, including pulmonary veno-occlusive disease, have been demonstrated in marrow allograft recipients. However, it is often difficult to make a correct diagnosis of pulmonary lesions. METHODS: An open lung biopsy was performed on a patient who developed severe pulmonary hypertension after bone marrow transplantation for T-cell lymphoma. RESULTS: An open lung biopsy specimen demonstrated pulmonary arterial occlusion due to intimal fibrosis and veno-occlusion. The most striking alteration was partial to complete occlusion of the small arteries by fibrous proliferation of the intima. CONCLUSION: High-dose preparative chemotherapy and radiation before transplantation are thought to have contributed to the development of vasculopathy in this patient, because arterial occlusion by intimal fibrosis and atypical veno-occlusion are often associated with lung injury due to chemoradiation. An open lung biopsy is essential for diagnosing pulmonary vascular disease presenting signs compatible with posttransplantation pulmonary hypertension.

Adult↗
PubMed2000

Ser298 of MITF, a mutation site in Waardenburg syndrome type 2, is a phosphorylation site with functional significance.

MITF (microphthalmia-associated transcription factor) is a basic-helix-loop-helix-leucine zipper (bHLHZip) factor which regulates expression of tyrosinase and other melanocytic genes via a CATGTG promoter sequence, and is involved in melanocyte differentiation. Mutations of MITF in mice or humans with Waardenburg syndrome type 2 (WS2) often severely disrupt the bHLHZip domain, suggesting the importance of this structure. Here, we show that Ser298, which locates downstream of the bHLHZip and was previously found to be mutated in individuals with WS2, plays an important role in MITF function. Glycogen synthase kinase 3 (GSK3) was found to phosphorylate Ser298 in vitro, thereby enhancing the binding of MITF to the tyrosinase promoter. The same serine was found to be phosphorylated in vivo, and expression of dominant-negative GSK3beta selectively suppressed the ability of MITF to transactivate the tyrosinase promoter. Moreover, mutation of Ser298, as found in a WS2 family, disabled phos-phorylation of MITF by GSK3beta and impaired MITF function. These findings suggest that the Ser298 is important for MITF function and is phosphorylated probably by GSK3beta.

Amino Acid Substitution↗
PubMed2000

Nonmuscle myosin II localizes to the Z-lines and intercalated discs of cardiac muscle and to the Z-lines of skeletal muscle.

To understand the role of nonmuscle myosin II in cardiac and skeletal muscle, we used a number of polyclonal antibodies, three detecting nonmuscle myosin heavy chain II-B (NMHC II-B) and two detecting NMHC II-A, to examine the localization of these two proteins in fresh-frozen, acetone-fixed sections of normal human and mouse hearts and human skeletal muscles. Results were similar in both species and were confirmed by examination of fresh-frozen sections of human hearts subjected to no fixation or to treatment with either 4% p-formaldehyde or 50% glycerol. NMHC II-B was diffusely distributed in the cytoplasm of cardiac myocytes during development, but after birth it was localized to the Z-lines and intercalated discs. Dual labeling showed almost complete colocalization of NMHC II-B with alpha-actinin. Whereas endothelial cells, smooth muscle cells and fibroblasts showed strong immunoreactivity for NMHC II-A and NMHC II-B, cardiac myocytes only showed reactivity for the latter. The Z-lines of human skeletal muscle cells, in contrast to those of cardiac myocytes, gave positive reactions for both NMHC II-A and NMHC II-B. The presence of a motor protein in the Z-lines and intercalated discs raises the possibility that these structures may play a more dynamic role in the contraction/relaxation mechanism of cardiac and skeletal muscle than has been previously suspected.

Actinin↗
PubMed2000

Activation of hepatic NKT cells and subsequent liver injury following administration of alpha-galactosylceramide.

It has been established that alpha-galactosylceramide (alpha-GalCer), a glycolipid, is recognized by natural killer T (NKT) cells together with the monomorphic MHC-like antigen, CD1d, in mice and humans. In this study, we examined how NKT cells are modulated by in vivo administration of alpha-GalCer in mice. When 2 microg (or more)/mouse of alpha(-GalCer was injected i.p., the majority of NKT cells disappeared in the liver and spleen, possibly undergoing apoptosis, on day 1. At this time, NKT cytotoxicity seen in liver lymphocytes also disappeared. In parallel with this numerical and functional change of NKT cells, there was always concomitant hepatocyte damage, as shown by histology and elevated levels of transaminases. Subsequently, the number and function of NKT cells continued to increase from day 3 to day 7. The response seen in hepatic (and splenic) NKT cells did not occur in thymic NKT cells. All these phenomena induced in the liver did not appear in NKT-deficient mice such as beta2-microglobulin(-/-) and CD1d(-/-) mice. These results shed further light on the in vivo interaction between NKT cells and alpha-GalCer in mice.

Aging↗
PubMed2000

RAR and RXR expression by Kupffer cells.

Retinoids are known to modulate macrophage differentiation, proliferation, and function including cytokine gene expression. However, signaling of retinoic acid (RA), a biologically active metabolite of vitamin A, in Kupffer cells has not been characterized. This study reports mRNA expression by rat Kupffer cells of RA receptor (RAR) and retinoid X receptor (RXR) subtypes and their binding activities to the RA responsive element (RARE) or retinoid X responsive element (RXRE). Total RNA and nuclear proteins were extracted from Kupffer cells immediately following isolation from livers of normal male Wistar rats. Competitive PCR demonstrated relative mRNA expression of RAR and RXR subtypes in the order of beta>alpha>gamma for and alpha>beta>gamma, respectively. It also demonstrated that the RXR alpha and beta mRNA levels were 5- to 10-fold higher in Kupffer cells than in hepatic stellate cells while RAR mRNA expression was shown to be similar for all the subtypes in both cell types. Gel mobility shift assays of nuclear extracts with labeled RARE and RXRE probes showed distinct binding activities for both responsive elements, which were effectively displaced with cold probes in excess but not with an unrelated oligonucleotide. A supershift assay with an antibody against RARalpha or RXRalpha has confirmed the contribution of both receptors to RARE binding and that of the RXRalpha to RXRE binding activity. These results represent the first demonstration of RA signaling at the nuclear level in Kupffer cells.

Animals↗
PubMed2000

Expression of perlecan proteoglycan in the infarct zone of mouse myocardial infarction.

Perlecan, a basal lamina proteoglycan, has been shown to interact with other extracellular matrix (ECM) components, especially type IV collagen, and is thus involved in ECM formation. Perlecan has also been postulated to promote growth factor-receptor interactions, including the binding of basic fibroblast growth factor (bFGF) to its receptor, and to enhance mitogenesis and angiogenesis. To test our hypothesis that perlecan is increased in the myocardial infarct zone, we examined perlecan expression after experimentally induced myocardial infarction in BALb/c mice by the methods of in situ hybridization, Northern blotting, and immunohistochemistry. In situ hybridization revealed mRNA signals for perlecan in the infarct marginal zone on day 2 and in the infarct interior zone around infarct granulation tissue on day 7. On day 14 the signals were observed at the center point of the infarct. The signals were detected in spindle-shaped mesenchymal cells (fibroblasts and myofibroblasts). Some surviving myocytes in the infarct marginal zone also showed positive signals. The sequential changes in the perlecan mRNA signal distribution paralleled those for type IV collagen mRNA. Northern blotting demonstrated increased expression of perlecan consistent with the observations of in situ hybridization. Immunopositive staining for perlecan was observed in the infarct zone around granulation tissue on day 7 and in the entire infarct zone on days 14-28. Immunostaining for bFGF was localized surrounding the infarct granulation tissue on day 7 and overlapped with perlecan immunostaining. The present results demonstrated the expression of perlecan by spindle-shaped mesenchymal cells (fibroblasts and myofibroblasts) and some surviving myocytes in the myocardial infarct, indicating the contribution of perlecan to the pathological course of myocardial infarction.

Animals↗
PubMed2000

The role of Stat3 in apoptosis and mammary gland involution. Conditional deletion of Stat3.

STATs (signal transducer and activator of transcription) are a family of latent transcription factors which are activated in response to a variety of cytokines and growth factors. This family of signalling molecules have been implicated in growth, differentiation, survival and apoptosis. In this article, we will review work which highlights the role of individual STAT factors in mammary gland and demonstrate the value of genetically modified mice in defining the function of STAT3. Involution of the mouse mammary gland is characterised by extensive apoptosis of the epithelial cells and the activation of STAT3. STATs 3 and 5 have reciprocal patterns of activation throughout a mammary developmental cycle suggesting that STAT5 may be a survival factor and STAT3 a death factor for differentiated mammary epithelium. To clarify the role of STAT3 in mammary epithelial apoptosis, we have generated a conditional knockout using the lox/Cre recombination system. Mammary glands from crosses of transgenic mice expressing Cre recombinase under the control of the beta-lactoglobulin milk protein gene promoter with mice harbouring one floxed STAT3 allele and one null STAT3 allele, showed a decrease in epithelial apoptosis and a dramatic delay of the involution process upon forced weaning. This was accompanied by precocious activation of STAT1 and increases in p53 and p21 levels--these may act as a compensatory mechanism for initiating the eventual involution which occurs in STAT3 null mammary glands. This demonstrates for the first time the importance of STAT factors in signalling the initiation of physiological apoptosis in vivo and highlights the utility of the lox/Cre system for addressing the function of genes, which have an embryonic lethal phenotype, specifically in mammary gland.

Animals↗
PubMed2000

Hepatoid adenocarcinoma of the gallbladder.

We describe here a rare case of hepatoid adenocarcinoma (HAC) of the gallbladder without the production of alpha-fetoprotein (AFP). A 77-year-old man was referred to our division with complaints of general fatigue, loss of appetite, and loss of body weight. A preoperative diagnosis of advanced gallbladder cancer was made, and cholecystectomy with combined resection of two liver subsegments (S4a + S5) and lymph node dissection were performed. Microscopically, the tumor was mainly composed of characteristic cells featuring eosinophilic cytoplasm, enlarged nuclei, and prominent nucleoi, arranged in nests or proliferated in a trabecular pattern. These features were highly suggestive of HAC of the gallbladder, and the tumor cells were negative for AFP immunohistochemical staining. The patient is doing well and has survived for 15 months postoperatively without any recurrence.

Adenocarcinoma↗
PubMed2000

Nationwide epidemiological survey of chronic pancreatitis in Japan.

The aim of this study was to estimate the number of patients treated for chronic pancreatitis in 1994 in Japan and to explore the clinico-epidemiological features of chronic pancreatitis. Two surveys were conducted. Stratified random sampling was used to select departments in which patients with chronic pancreatitis were treated, and two different questionnaires were administered to obtain relevant information. From the first survey, the total number of patients treated for chronic pancreatitis in Japan in the year 1994 was estimated as 32,000 (95% confidence interval, 25,000-39,000). Clinico-epidemiological features, based on the 2,523 patients reported from the second survey, were subsequently clarified. The sex ratio (male/female) of the patients was 3.5. Alcoholic pancreatitis was the most common type in males (68.5%), and idiopathic pancreatitis in females (69.6%). Compared with the findings in the last survey in 1985, the proportion of patients with alcoholic pancreatitis has decreased slightly, from 58.7% to 55.5%, while that of idiopathic chronic pancreatitis has increased in both males and females. Patients diagnosed by advanced techniques such as computed tomography (CT) and endoscopic retrograde cholangiopancreatography (ERCP) accounted for 68.1% of the total. The number of patients with chronic pancreatitis treated in 1994 in Japan, was estimated as 32,000, with an overall prevalence rate of 45.4 per 100,000 population in males and 12.4 per 100,000 population in females.

Adolescent↗