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Biomedical subjects

T Ishida

Publications and source records attributed to T Ishida.

At least 181 records · Page 10Linked to original sources
PubMed2000

TNF-alpha stimulation of MCP-1 expression is mediated by the Akt/PKB signal transduction pathway in vascular endothelial cells.

MCP-1 is expressed in a variety of cell types including vascular endothelial cells following induction by different stimuli such as tumor necrosis factor (TNF)-alpha. Although TNF-alpha stimulates MCP-1 expression and secretion, the mechanism by which TNF-alpha stimulates expression of the MCP-1 gene is not known. In this study, we examine the involvement of the phosphatidylinositol-3-OH kinase (PI3-kinase)-Akt/PKB pathway. Exposure of human umbilical vein endothelial cells (HUVECs) to TNF-alpha elicited the rapid phosphorylation of Akt/PKB. In HUVECs, wortmannin, a PI3-kinase inhibitor, inhibits TNF-alpha-mediated MCP-1 secretion at a dose-dependent manner. Constitutively active form of Akt/PKB induces transcription of the MCP-1 gene, and cotransfection of dominant negative Akt/PKB suppressed the activation of the MCP-1 promoter induced by TNF-alpha. These findings show that Akt/PKB participates in the TNF-alpha induction of MCP-1 gene transcription in endothelial cells.

Androstadienes↗
PubMed2000

Biodistribution of liposomes and C3 fragments associated with liposomes: evaluation of their relationship.

The biodistribution of liposomes with two different kind phospholipids (hydrogenated egg phosphatidylcholine and egg phosphatidylcholine) plus cholesterol (CHOL) were investigated after intravenous administration to rats. Elimination of liposomes from blood circulation was affected by the lipid composition. It appeared that the inclusion of CHOL in liposomes accelerates the rate of liposome uptake by liver, resulting in rapid elimination of liposomes. The amount of C3 fragments bound to liposomes was quantitatively determined to assess the contribution of the complement system to liposome accumulation into organs and liposome destabilization in vivo and in vitro. The amount of bound C3 fragments was directly proportional to CHOL content, and the amount was also proportional to the CLh, CLs as well as CLrel. This relationship suggests that the complement system is responsible for the elimination of liposomes from blood circulation, presumably as a consequence of opsonization by C3 fragments and assembly of membrane attack complex (MAC) onto liposomes. In addition, substitution of cholesteryl methyl ether into the liposome formulation for CHOL significantly diminished not only the binding of C3 fragments but also the CLh, CLs and CLrel, resulting in increased mean resident time (MRT) of the liposomes. This result suggests that the hydroxyl-group on CHOL is a binding site for C3 fragments on the liposomes and that CHOL in a liposome formulation promotes the accumulation of liposomes into the liver and spleen, probably due to their uptake by phagocytic cells, and impairs the stability of the liposomes in blood circulation, via a mechanism involving the complement system.

Animals↗
PubMed2000

Suppression of carbonic anhydrase III in rat liver by a dioxin-related toxic compound, coplanar polychlorinated biphenyl, 3, 3',4,4',5-pentachlorobiphenyl.

A coplanar polychlorinated biphenyl, 3,3',4,4',5-pentachlorobiphenyl (PenCB), significantly suppresses the expression of rat liver carbonic anhydrase III (CAIII), an enzyme which has recently been suggested to prevent from H(2)O(2)-inducible apoptosis. Marked changes in the CAIII levels of liver cytosol were observed in rats following doses of PenCB ranging from 0.5 to 25 mg/kg body weight and maximum suppression was observed at a dose of 10 mg/kg. Northern analysis revealed that the level of CAIII mRNA in rat liver was dramatically reduced by PenCB treatment while only weak suppression was observed in pair-fed controls. Two AU-rich elements, considered as a destabilizing signal of mRNA, were found in the 3'-untranslated region of CAIII sequenced after reverse transcription-PCR and 3'-rapid amplification of the cDNA end. Dramatic decrease of CAIII in rat liver by PenCB could account for the suppression of the defense system for oxidative stress.

3' Untranslated Regions↗
PubMed2000

Regulated expression of endothelial cell-derived lipase.

A lipoprotein lipase-like gene was recently cloned from endothelial cells. In vitro functional experiments have suggested that this endothelial-derived lipase (EDL) has phospholipase activity, and preliminary in vivo studies have suggested a role in the regulation of high-density lipoprotein metabolism. To investigate local control of lipase activity and lipid metabolism in the blood vessel wall, we have examined the regulation of EDL expression in cultured human umbilical vein and coronary artery endothelial cells. EDL mRNA levels were upregulated in both cell types by inflammatory cytokines implicated in vascular disease etiology, including TNF-alpha and IL-1beta. In addition, both fluid shear stress and cyclic stretch were found to increase the EDL mRNA levels in these cultured cells. This highly regulated expression of EDL in vascular endothelial cells suggests that this recently identified lipase is intricately involved in modulating vessel wall lipid metabolism and may play a role in vascular diseases such as atherosclerosis.

Arteriosclerosis↗
PubMed2000

Bacterial cellulose production by Acetobacter xylinum in a 50-L internal-loop airlift reactor.

Bacterial cellulose (BC) production was realized in a batch cultivation of Acetobacter xylinum subsp. sucrofermentans BPR2001 in a 50-L internal-loop airlift reactor. When the bacterium was cultivated with air supply, 3.8 g/L of BC was produced after 67 hours. When oxygen-enriched gas was supplied, the concentration of BC was doubled and the production rate of BC was 0.116 g/L. h, which was two times higher than that of air-supplied culture and comparable to that in a mechanically agitated stirred-tank fermentor. Bacterial cellulose produced by the airlift reactor formed a unique ellipse pellet (BC pellet), different from the fibrous form which was produced in an agitated stirred-tank fermentor. The BC-pellet suspension was demonstrated to have a higher volumetric oxygen transfer coefficient than the fibrous BC suspension in a 50-L internal-loop airlift reactor. The mixing time of BC-pellet suspension in the airlift reactor was also shorter than that in water.

Air↗
PubMed2000

Ectopic p16(ink4) expression enhances CPT-11-induced apoptosis through increased delay in S-phase progression in human non-small-cell-lung-cancer cells.

A tumor-suppressor gene, p16(INK4), which is deleted or mutated in tumors, regulates cell-cycle progression through a G(1)-S restriction point by inhibiting CDK4(CDK6)/cyclin-D-mediated phosphorylation of pRb. We have found that ectopic p16(INK4) expression increased cellular sensitivity of human non-small-cell-lung-cancer (NSCLC) A549 cells to a selective growth-inhibitory effect induced by the topoisomerase-I inhibitor 11, 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxy camptothecin (CPT-11) in vitro. In this study, we observed enhanced apoptosis characterized by DNA fragmentation in A549 cells transfected with p16(INK4) cDNA (A549/p16-1) and treated with CPT-11. This apoptosis was suppressed by the inhibitor of interleukin-1beta-converting enzyme (ICE/caspase-1) or ICE-like proteases, Z-Asp-CH2-DCB, as determined by DNA fragmentation and proteolytic cleavage of poly(ADP-ribose) polymerase, a natural substrate for CPP32/caspase-3. In A549/p16-1 cells, cytosolic peptidase activities that cleaved Z-DEVD-7-amino-4-trifluoromethylcoumarin increased during CPT-11-induced apoptosis and were suppressed by a highly specific caspase-3 and caspase-3-like inhibitor, Z-DEVD-fluoromethylketone. These findings indicate that p16(INK) is positively involved in the activation pathway of the caspase-3 induced by CPT-11. The increased delay in S-phase progression and subsequent induction of apoptosis were observed in CPT-11-treated A549/p16-1 cells on the basis of DNA histograms. Specific down-regulation of the cyclin-A protein level in A549/p16-1 cells was observed after CPT-11-treatment, whereas cyclin B, cdk2, and cdc2 protein levels were unaffected. These results suggest that ectopic p16(INK4) expression inappropriately decreases cyclin A and thereby terminates CPT-11-induced G(2)/M accumulation, which is followed by increased apoptosis in p16(INK4)-expressing A549 cells.

Antineoplastic Agents, Phytogenic↗
PubMed2000

Interleukin 18 and interleukin 1beta production is decreased in HIV type 1-seropositive hemophiliacs but not in HIV type 1-seropositive nonhemophiliacs.

In Japan, the proportion of hemophiliacs infected with human immunodeficiency virus type 1 (HIV-1) is 40%, whereas more than 90% are infected with hepatitis C virus (HCV). To evaluate the immunological status of hemophiliacs infected with HIV-1, we investigated the pattern of cytokine production in peripheral blood mononuclear cells (PBMCs) of HIV-1-seropositive and -seronegative hemophiliacs, HIV-1-seropositive non-hemophiliacs, and healthy individuals. The production of IL-18 and IL-1beta from PBMCs stimulated with Staphylococcus aureus Cowan strain 1 (SAC) in the HIV-1-seropositive hemophiliacs was significantly decreased in comparison with the other groups. On the other hand, IL-12 production in both HIV-1-seropositive groups was significantly lower than in HIV-1-seronegative groups. TNF-alpha and IL-6 production was similar among the four groups. In contrast, plasma levels of TGF-beta1 were increased in HIV-1-seropositive hemophiliacs, HIV-1-seropositive nonhemophiliacs, and HIV-1-seronegative hemophiliacs, with the highest levels being in HIV-1-seropositive hemophiliacs, suggesting that coinfection with HIV-1 and HCV increases the level of plasma TGF-beta in HIV-1-seropositive hemophiliacs. Treatment of PBMCs from healthy individuals with TGF-beta1 inhibited IL-18 and IL-1beta production without affecting IL-6, IL-10, or TNF-alpha production. Suppression of the expression of caspase 1 mRNA, which is known to be an IL-1beta-converting enzyme and which also cleaves the precursor of IL-18, was observed in the SAC-stimulated PBMCs from healthy individuals after treatment with TGF-beta1 and in the SAC-stimulated PBMCs from HIV-1-seropositive hemophiliacs, suggesting that the decreased production of IL-18 and IL-1beta in HIV-1-seropositive hemophiliacs may be related to the downregulation of caspase 1 mRNA induced by high levels of TGF-beta1 in plasma.

Adolescent↗
PubMed2000

Resistance to endotoxin shock in transgenic mice overexpressing endothelial nitric oxide synthase.

BACKGROUND: Nitric oxide (NO) plays a central role in the pathogenesis of septic shock. However, the role of the NO produced by endothelial NO synthase (eNOS) in septic shock is still unclear. We examined the effect of chronic eNOS overexpression and the role of eNOS-derived NO in lipopolysaccharide (LPS)-induced septic shock using eNOS transgenic (Tg) mice. METHODS AND RESULTS: LPS was intraperitoneally injected into Tg and control mice. No differences existed in the peak plasma nitrate and nitrate levels induced by LPS between the 2 genotypes. In LPS-treated control mice, blood pressure progressively declined and reached 60% of basal levels (from 97+/-3 to 59+/-3 mm Hg) 24 hours after LPS injection. In contrast, the blood pressure of LPS-treated Tg mice fell only 15% from basal levels (from 84+/-4 to 71+/-4 mm Hg) after the first 6 hours and, thereafter, it remained at this level. LPS-induced increases in the expression of the mRNA of both vascular cell adhesion molecule-1 and intracellular adhesion molecule-1 in the lungs were significantly lower in Tg mice than in control mice. LPS-induced pulmonary leukocyte infiltration and increases in lung water content were also significantly attenuated in Tg mice. Histological examination revealed that lung injury after LPS injection was milder in Tg mice. Furthermore, Tg mice exhibited enhanced survival from LPS-induced septic shock compared with control mice. CONCLUSIONS: Chronic eNOS overexpression in the endothelium of mice resulted in resistance to LPS-induced hypotension, lung injury, and death. These effects are associated with the reduced vascular reactivity to NO and the reduced anti-inflammatory effects of NO.

Animals↗
PubMed2000

A novel cryptic exon in intron 2 of the human dystrophin gene evolved from an intron by acquiring consensus sequences for splicing at different stages of anthropoid evolution.

The dystrophin gene, which is mutated in Duchenne muscular dystrophy, is thus the largest human gene. A full spectrum of splicing of the dystrophin transcript has not been elucidated yet, though more than 10 alternative splicings have been identified in the 5' region of the dystrophin gene. In this study, two novel dystrophin transcripts containing a 140-nucleotide insertion precisely between exons 2 and 8 or between exons 2 and 18 were identified in skeletal muscle. The genomic region corresponding to and surrounding this 140-nucleotide sequence was sequenced to reveal that the insertion possessed a branch point and both acceptor and donor splice site consensus sequences perfectly. Therefore, the 140-bp insertion sequence was considered to be a novel exon. The novel exon was mapped to intron 2 and was designated exon 2a. Reverse-transcription PCR screening for transcripts containing exon 2a in 12 human tissues revealed its presence in 3 of them, including skeletal muscle. Phylogenetic studies disclosed that exon 2a evolved from intron DNA by the progressive acquisition of nucleotide substitutions in ancestral hominoids.

Animals↗
PubMed2000

Amphipathic structure of theonellapeptolide-Id, a hydrophobic tridecapeptide lactone from the Okinawa marine sponge Theonella swinhoei.

Theonellapeptolide-Id (TNLP), a cyclic tridecapeptide lactone, was crystallized from dimethylformamide-water solution. In the asymmetric unit, two peptide molecules were combined with solvent molecules, and the total molecular weight was over 3000 Dalton. The crystal structure including solvent molecules was finally determined at 0.80 A resolution using synchrotron radiation. The conformations of two independent molecules were similar to each other and were also similar to the previously reported structure (Doi, Ishida, Kobayashi, Deschamps and Flippen-Anderson, 1999, Acta Crystallogr Sect C, 55, 796-798). About 13 hydrated water molecules were found at disordered 19 sites; they were located at a certain region to avoid contact with aliphatic side-chains of peptolide in the crystal. The spatial disposition of the solvent molecules and peptides subsequently caused the formation of the amphipathic layer.

Animals↗
PubMed2000

Requirement of activation of the extracellular signal-regulated kinase cascade in myocardial cell hypertrophy.

The signal transduction mechanisms mediating hypertrophic responses in myocardial cells (MCs) remain uncertain. We investigated the role of the extracellular signal-regulated kinase (ERK) cascade in myocardial cell hypertrophy by the strategy of using the adenovirus-mediated overexpression of mitogen-activated protein kinase (MAPK)/ERK kinase (MEK), which is the upstream activator of ERK. We generated recombinant adenoviruses expressing constitutively active MEK1 (MEK1 EE) and dominant negative MEK1 (MEK1 DN). Overexpression of MEK1 EE in MCs activated ERK1/2 and subsequently induced atrial natriuretic peptide (ANP) mRNA expression. In addition, MEK1 EE overexpression resulted in an increase in cell size and sarcomeric reorganization. In contrast, overexpression of MEK1 DN in MCs inhibited endothelin-1 (ET-1)-, phenylephrine (PE)-, leukemia inhibitory factor (LIF)-, isoproterenol (ISP)-, and mechanical stretch-induced ERK activation and ANP mRNA expression. MEK1 DN overexpression inhibited ET-1-, PE-, LIF-, and ISP-induced increases in cell size and sarcomeric reorganization. Consistent with the observed effects on cellular morphology, overexpression of MEK1 EE resulted in an increase in amino acid incorporation, while overexpression of MEK1 DN inhibited ET-1-, PE-, LIF-, ISP-, and mechanical stretch-induced increases in amino acid incorporation. These results indicate that the ERK cascade plays an important role in the signaling pathway leading to the development of myocardial cell hypertrophy.

Adenoviridae↗
PubMed2000

Resting 123I-BMIPP scintigraphy for detection of organic coronary stenosis and therapeutic outcome in patients with chest pain.

PURPOSE: Resting 123I-BMIPP scintigraphy can detect coronary artery disease based on persistent abnormality of myocardial fatty acid metabolism after transient ischemia. The present study aimed to determine the value of resting 123I-BMIPP scintigraphy in diagnosing coronary artery disease and predicting the therapeutic outcome in patients with chest pain symptom. METHOD: Five hospitals participated in this study, and scintigraphic and angiographic studies were performed in 104 patients without myocardial infarction. Twenty of them had non-coronary artery disease (chest pain syndrome), 26 had stable effort angina, 35 had unstable angina with organic coronary lesions, and 23 had vasospastic angina without significant organic stenosis. RESULTS: Overall sensitivity for diagnosing angina pectoris (stable, unstable and vasospastic) was 45%, and overall specificity for excluding non-coronary artery disease was 80%. The incidence of positive 123I-BMIPP was 54% among patients with organic coronary stenosis (50% in stable angina and 61% in unstable angina with organic stenosis), but it was low (22%) in vasospastic angina without organic stenosis. Patients with advanced coronary stenosis and multi-vessel disease were found to have a higher incidence of positive 123I-BMIPP. A positive 123I-BMIPP result was correlated with a higher rate of subsequent intervention therapy (catheter intervention or CABG) than a negative result (48% versus 27%, p = 0.03 at one month; and 63% versus 35%, p = 0.008 at one year). CONCLUSION: Resting 123I-BMIPP scintigraphy was valuable in detecting advanced coronary lesions in angina patients associated with a high incidence of subsequent intervention therapy.

Aged↗
PubMed2000

Immunohistochemical expression of the CD44 variant 6 in colorectal adenocarcinoma.

The CD44 variant 6 (CD44 v6) has been postulated to be involved in both carcinogenesis and tumor progression. In the present study, CD44 v6 was stained immunohistochemically in 63 colorectal cancer tissues to assess significance of CD44 v6 in the carcinogenesis and progression of colorectal carcinoma. None of the normal colonocytes showed an expression of CD44 v6. CD44 v6 expression was very strong in 24, moderate in 13, and negative in 26 tumor tissues. A negative or moderate expression of CD44 v6 was significantly associated with a larger tumor size (P < 0.05) and invasion through the bowel wall (P < 0.01). There was no correlation between the expression of CD44 v6 and gross type, histologic differentiation, lymph node involvement, liver metastasis, and clinical stage of the disease. The present study showed that the expression of CD44 v6 was characteristic of neoplastic changes in the colonocytes and that a diminished expression of CD44 v6 was associated with the penetration of colorectal cancer through the bowel wall, but not with either lymph node or distant metastasis.

Adenocarcinoma↗
PubMed2000

Differentially expressed mRNAs in androgen-independent but not androgen-dependent Shionogi carcinoma.

UNLABELLED: Recently, a new and highly effective method termed suppressive subtractive hybridization (SSH) has been introduced to clone differentially expressed mRNAs. Genes expressed in androgen-independent but not in androgen-dependent tumors, and vice versa, are obviously significant to delineate the mechanisms of androgen dependency/independency of these tumors. Mouse mammary cancer (Shionogi carcinoma-115) has been extensively used to analyze the mechanism of androgen-dependent cancer growth. METHODS: We cloned androgen-independent and androgen-dependent Shionogi carcinoma-115 specific mRNAs by the SSH method. Cloned sequences were compared with known sequences using NCBI BLAST across the Internet. Two clones were positive for cDNA insert when androgen-independent cDNA was used as tester cDNA, while no clones were positive using the androgen-dependent tester cDNA. One of the former was mouse protein kinase C beta-II while the other was a new DNA sequence. Mouse protein kinase C beta-II mRNA and the new mRNA were shown to be differentially expressed by RT-PCR analysis in androgen-independent but not androgen-dependent Shionogi carcinoma. Two mRNA species differentially expressed in androgen-independent but not androgen-dependent Shionogi carcinoma were cloned by the SSH method. The significance of these mRNAs for androgen-dependency/independency of Shionogi carcinoma should be explained in future studies.

Androgens↗
PubMed2000

Elevation of anti-cytokeratin 18 antibody and circulating cytokeratin 18: anti-cytokeratin 18 antibody immune complexes in sera of patients with idiopathic pulmonary fibrosis.

In this study, we hypothesize that anti-cytokeratin 18 (CK18) antibody and CK18:anti-CK18 immune complex increase in sera in patients with idiopathic pulmonary fibrosis (IPF). To prove the existence of anti-CK18 antibodies in patients' sera, bovine CK18 was stained with patients' sera using a Western blotting. In patients with IPF, anti-CK18 antibodies were clearly demonstrated in sera by Western blotting. Then, we tried to establish an enzyme-linked immunosorbent assay (ELISA) to quantify anti-CK18 antibodies and CK18:anti-CK18 immune complexes in sera of patients with IPF. Levels of anti-human CK18 antibodies in sera of patients with IPF (0.81 +/- 0.31, mean +/- SD) measured by ELISA were significantly high compared with that of normal volunteers (0.45 +/- 0.06, p < 0.01). In addition, levels of CK18:anti-CK18 antibody complexes in patients' sera (0.64 +/- 0.35, man +/- SD) significantly increased compared with those of normal subjects (0.40 +/- 0.10, p < 0.01). These results suggest that anti-CK18 antibody and its immune complex may have played a role in the process of lung injury in IPF.

Adult↗
PubMed2000

Keratin 14 immunoreactive cells in pleomorphic adenomas and adenoid cystic carcinomas of salivary glands.

Our recent study of developing myoepithelial cells (MECs) in rat salivary glands demonstrated that developing MECs begin to express alpha-smooth muscle actin (alphaSMA) first and, thereafter, keratin 14. Therefore, it is unlikely that duct basal cells expressing keratin 14 alone are immature or undifferentiated MECs. In this study we carried out immunohistochemistry of pleomorphic adenomas and adenoid cystic carcinomas including normal salivary glands using monoclonal antibodies to keratin 14, smooth muscle proteins and keratin 19. The smooth muscle proteins examined included alphaSMA, h-caldesmon and h1-calponin; h1-calponin was observed in keratinocytes and nerve fibers, indicating that the protein is not specific to smooth muscle, whereas alphaSMA and h-caldesmon turned out to be highly specific markers for smooth muscle cells in normal tissues. In normal glands, MECs were positive for both keratin 14 and smooth muscle proteins (alphaSMA and h-caldesmon). Non-MEC cells were essentially devoid of smooth muscle proteins. Non-MEC duct basal cells expressed keratin 14 with or without keratin 19, and luminal cells keratin 19 with or without keratin 14. This suggests that the keratin 14-positive, smooth muscle proteins-negative duct basal cells are luminal cell progenitors. Luminal cells in tubular structures of both tumors were positive for keratin 19 with or without keratin 14. Nonluminal peripheral cells of pleomorphic adenomas were mostly positive for keratin 14, and a small fraction of them expressed smooth muscle proteins. Conversely, peripheral cells of adenoid cystic carcinomas were mostly positive for smooth muscle proteins, and some of them expressed keratin 14. These results strongly suggest (1) that the luminal cell progenitors transform into major constituents of pleomorphic adenoma cells with keratin 14 but not smooth muscle proteins, and (2) that the peripheral cells of adenoid cystic carcinoma are derived from undifferentiated MECs. Solid structures of pleomorphic adenomas were formed by proliferation of the peripheral cells. MECs were observed only occasionally in the periphery. Solid and cribriform structures of adenoid cystic carcinomas were formed by proliferation of the luminal cells. MECs were observed in the periphery and around the pseudocyst.

Actins↗
PubMed2000

Non-traumatic osteonecrosis of the femoral head treated with transtrochanteric anterior rotational osteotomy combined with vascularized iliac bone grafting.

A 49-year-old Japanese man who had non-traumatic osteonecrosis of the femoral head with a wide necrotic lesion received transtrochanteric anterior rotational osteotomy combined with vascularized iliac bone grafting. After the bone graft (6 x 1.5 cm) was collected, the femoral head was anteriorly rotated by 90 degrees. A bone tunnel of 1.2 cm in diameter was prepared on the necrotic lesion adjacent to the intact area from the anterior part of the femoral neck to inside the femoral head. The bone graft was trimmed to the size of this bone tunnel, and inserted up to immediately below the articular surface. In the monitoring using T1-weighted magnetic resonance imaging (MRI), the low signal-intensity area between the bone graft and intact area had disappeared, and a high signal-intensity area on the weight-bearing portion of the femoral head had extended. With modifications on the insertion point of the bone graft, transtrochanteric anterior rotational osteotomy combined with vascularized iliac bone graft would be a useful means to preserve the femoral head in large non-traumatic osteonecrosis of the femoral head.

Bone Transplantation↗