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Biomedical subjects

T Ishida

Publications and source records attributed to T Ishida.

At least 127 records · Page 7Linked to original sources
PubMed2001

Tissue-engineered vascular autograft: inferior vena cava replacement in a dog model.

Tissue-engineered vascular autografts (TEVAs) were made by seeding 4-6 x 10(6) of mixed cells obtained from femoral veins of mongrel dogs onto tube-shaped biodegradable polymer scaffolds composed of a polyglycolid acid (PGA) nonwoven fabric sheet and a copolymer of L-lactide and caprolactone (n = 4). After 7 days, the inferior vena cavas (IVCs) of the same dogs were replaced with TEVAs. After 3, 4, 5, and 6 months, angiographies were performed, and the dogs were sacrificed. The implanted TEVAs were examined both grossly and immunohistologically. The implanted TEVAs showed no evidence of stenosis or dilatation. No thrombus was found inside the TEVAs, even without any anticoagulation therapy. Remnants of the polymer scaffolds were not observed in all specimens, and the overall gross appearance similar to that of native IVCs. Immunohistological staining revealed the presence of factor VIII positive nucleated cells at the luminal surface of the TEVAs. In addition, lesions were observed where alpha-smooth muscle actin and desmin positive cells existed. Implanted TEVAs contained a sufficient amount of extracellular matrix, and showed neither occlusion nor aneurysmal formation. In addition, endothelial cells were found to line the luminal surface of each TEVA. These results strongly suggest that "ideal" venous grafts with antithrombogenicity can be produced.

Animals↗
PubMed2001

Expression of carcinoembryonic antigen in peripheral- or central-located small cell lung cancer: its clinical significance.

BACKGROUND: Small cell lung cancer (SCLC) has a higher percentage of hilar masses than other histological types of lung cancer. The primary site is usually adjacent to the hilum, but we often observe primary sites in the peripheral lung field. In this study, our objectives were to elucidate whether peripheral-located small cell lung cancer (PSCLC) is an independent entity and whether it differs clinically from central-located small cell lung cancer (CSCLC). METHODS: We reviewed the clinical and pathological features of 52 patients treated at Kagawa Medical University Hospital between 1987 and 1996 with a diagnosis of SCLC. We defined CSCLC as a tumor whose primary site is located in the segmental bronchi or more proximally and PSCLC as a tumor located distal to the subsegmental bronchi. Twenty-one PSCLC patients and 31 CSCLC patients were identified. Kaplan-Meier survival curves were constructed and comparisons were made between PSCLC and CSCLC by the log-rank test. The carcinoembryonic antigen (CEA) level was also evaluated in each group. RESULTS: Although the percentage of limited disease (LD) in the patients with PSCLC was higher than that in the patients with CSCLC, the 3-year survival rate of PSCLC tended to be worse than that of CSCLC (9% for patients with PSCLC and 29% for those with CSCLC). Survival curves of patients with PSCLC also tended to be worse than those of patients with CSCLC, not only in the limited disease group but also in the extensive disease (ED) group. In addition, the mean CEA value in patients with PSCLC was higher than that in patients with CSCLC (p < 0.001), whereas the neuron specific enolase (NSE) level was not significantly different between PSCLC and CSCLC. The median survival of patients with pretherapeutic CEA titers of > or =5 ng/ml was significantly shorter than that in patients with CEA levels <5 ng/ml. CONCLUSION: These findings suggest that the survival of SCLC patients with a high CEA level was significantly shorter than that of patients with a low CEA level. In addition, CEA levels in PSCLC patients were significantly higher than those in CSCLC patients. However, the survivals of LD or ED patients with PSCLC and CSCLC were not statistically different.

Adenocarcinoma↗
PubMed2001

Purification and characterization of homo- and hetero-dimeric acetate kinases from the sulfate-reducing bacterium Desulfovibrio vulgaris.

Two distinct forms of acetate kinase were purified to homogeneity from a sulfate-reducing bacterium Desulfovibrio vulgaris Miyazaki F. The enzymes were separated from the soluble fraction of the cells on anion exchange columns. One acetate kinase (AK-I) was a homodimer (alpha(S)(2)) and the other (AK-II) was a heterodimer (alpha(S)alpha(L)). On SDS-PAGE, alpha(L) and alpha(S) subunits migrated as bands of 49.3 and 47.8 kDa, respectively, but they had an identical N-terminal amino acid sequence. A rapid HPLC method was developed to directly measure ADP and ATP in assay mixtures. Initial velocity data for AK-I and AK-II were collected by this method and analyzed based on a random sequential mechanism, assuming rapid equilibrium for the substrate binding steps. All kinetic parameters for both the forward acetyl phosphate formation and the reverse ATP formation catalyzed by AK-I and AK-II were successfully determined. The two enzymes showed similar kinetic properties in Mg(2+) requirement, pH-dependence and magnitude of kinetic parameters. These results suggest that two forms of acetate kinase are produced to finely regulate the enzyme function by post-translational modifications of a primary gene product in Desulfovibrio vulgaris.

Acetate Kinase↗
PubMed2001

Binding diversity of a noncovalent-type low-molecular-weight serine protease inhibitor and function of a catalytic water molecule: X-ray crystal structure of PKSI-527--inhibited trypsin.

PKSI-527 is a noncovalent-type low-molecular-weight inhibitor. The X-ray crystal structure of the trypsin-PKSI-527 complex revealed a binding mode (Form II) different from the previously reported one (Form I) [Nakamura, M. et al. (1995) Biochem. Biophys. Res. Commun. 213, 583--587]. In contrast to the previous case, the electron density of the inhibitor revealed the whole structure clearly. Each structural part of the inhibitor in Forms I and II was differently located at the active site, although the modes of binding of the terminal amino group to the Asp189 carboxyl group were similar. This binding diversity, which is a characteristic of the noncovalent-type low-molecular-weight inhibitor, provides a suitable example for estimating the possible mechanism toward the enzymatic inhibition, together with the structural basis necessary for a specific inhibitor. The mode of binding in Form II reflects the inhibitor-specific situation and is in contrast with the substrate-mimetic binding mode for Form I. Based on the generally accepted catalytic mechanism for serine protease, we propose that a water molecule located at the catalytic site plays an important role in blocking the catalytic function of the reactive Ser193 OH group.

Animals↗
PubMed2001

Frontal gel chromatographic analysis of the interaction of a protein with self-associating ligands: aberrant saturation in the binding of flavins to bovine serum albumin.

Frontal gel chromatography is an accurate method to obtain the total free ligand concentration of a protein-ligand mixture in which ligands self-associate. The average number of bound ligands per protein molecule is obtained as a function of the total free ligand concentration. The method was applied to the interaction of bovine serum albumin with self-associating flavins. The binding curves for FMN and FAD leveled off at about 0.7 and 0.5, respectively. These data were simulated well by a binding model where flavins undergo isodesmic indefinite self-association and the monomer alone binds to a single binding site of albumin. The isodesmic association constants of FMN and FAD were (1.7 +/- 0.1) x 10(2) and (2.2 +/- 0.3) x 10(2) M(-1), respectively. The binding constants of the monomer of FMN and FAD were (7.6 +/- 0.2) x 10(2) and (3.5 +/- 0.2) x 10(2) M(-1), respectively. FMN competitively inhibited the binding of FAD to albumin. The affinity to flavins was in the following order at pH 5.8: lumiflavin, FMN, riboflavin, and FAD. The SH modification and the binding of palmitate did not affect the FMN binding to bovine albumin at pH 5.8. As pH increased from 5.8 to 9.0, the affinity to FMN of bovine albumin decreased 3-fold, whereas that of human albumin increased about 80-fold. The present study clearly showed how isodesmic self-association of a ligand can cause apparent saturation of the interaction of a protein with the ligand at levels lower than 1.

Animals↗
PubMed2001

Efficacy of intrathecal liposomal fasudil for experimental cerebral vasospasm after subarachnoid hemorrhage.

OBJECTIVE: To investigate the safety and efficacy of liposomal fasudil in a sustained-release form for the prevention of cerebral vasospasm after subarachnoid hemorrhage (SAH). METHODS: Eighteen rats were divided into three groups, each of which received 2.5 mg/kg of liposomal fasudil, 5 mg/kg of liposomal fasudil, or drug-free liposomes after SAH. Next, experimental SAH was induced in 15 dogs by injection of autologous arterial blood into the cisterna magna twice after baseline vertebral angiography. In six dogs, 0.94 mg/kg of liposomal fasudil was injected into the cisterna magna (treatment group). In four dogs, drug-free liposomes were similarly injected (placebo group), and the remaining five dogs were not treated with liposomal injection after SAH (control group). Angiography was repeated on Day 7, and cerebrospinal fluid was collected before the dogs were killed. RESULTS: A high dose of liposomal fasudil caused no significant changes in mean arterial blood pressure and did not induce seizures during the observation period. Gross and microscopic examination of the brains revealed no abnormalities, but severe vasospasm was noted in the rat basilar artery, mainly in the group treated with drug-free liposomes. Likewise, in the canine placebo and control groups, significant vasospasm occurred in the basilar artery on Day 7. In the treatment group, vasospasm in the basilar artery was significantly ameliorated (P < 0.01). In vivo, 90% of fasudil was released from liposomes in the cerebrospinal fluid. CONCLUSION: A single injection of intrathecal liposomal fasudil is safe and effective for the prevention of vasospasm in experimental SAH.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2001

Structural studies on C-amidated amino acids and peptides: structures of hydrochloride salts of C-amidated Ile, Val, Thr, Ser, Met, Trp, Gln and Arg, and comparison with their C-unamidated counterparts.

To elucidate the structural features of amino acids caused by the C-terminal alpha-amidation, the crystal structures of HCl salts of C-terminal amidated Ile, Val, Thr, Ser, Met, Trp, Gln and Arg were analysed and compared with those of their C-terminal free acids. The bonding parameter of the amide group was little affected by the different chemical properties of the side chains. As for the molecular packing patterns, some structural differences were observed by the C-amidation. The Calpha-H...O hydrogen bonds and carbonyl-carbonyl interactions were more strengthened by the salt formation with HCl in C-amides than C-acids. Furthermore, there is a clear difference between the interaction patterns with Cl ions. In most C-amide crystals, Cl ions are bifurcately hydrogen-bonded to two neighbouring amide NH(2) groups and the parallel layers of the C-amides and Cl ions are alternatively formed. In the case of the carboxyl OH in C-acid crystals, however, the direct hydrogen bond with the Cl ion is not always observed and is largely dependent on the crystal packing environment. This suggests the superior hydrogen-bonding ability of NH...Cl(-) compared with OH...Cl(-). The difference in hydrogen-bonding ability between the amide and carboxyl groups is considered, based on the spatial dispositions of the hydrogen-bonding polar atoms/groups.

Amides↗
PubMed2001

Age changes in plasma IGF-1 concentration in free-ranging Japanese macaques (Macaca fuscata).

To obtain fundamental data on the endocrine background for the wild Japanese macaque (Macaca fuscata) growth profiles, we have measured plasma insulin-like growth factor 1 (IGF-1) concentrations of free-ranging and open-enclosed Japanese macaques from five different regions in their habitat. General features of the IGF-1 levels in those troops were: 1) an age-dependent increase in the young macaques and 2) distinctively higher values among several adult females. The age changes in IGF-1 levels during the adolescent period in the free-ranging Japanese macaques were similar to those in the caged Japanese macaques.

Aging↗
PubMed2001

Non-specific interstitial pneumonia as pulmonary involvement of systemic sclerosis.

The pathological features of lung disease in nine patients with systemic sclerosis (SSc) were evaluated. The patients comprised one man and eight women, with a median age of 58 years. SSc was diagnosed according to the criteria of the American Rheumatism Association. In all patients, high resolution computed radiographic scanning of the lungs (HRCT) was performed, and apparent honeycomb formation was seen in four patients. Pathologically, four patients were diagnosed with usual interstitial pneumonia (UIP), three with non-specific interstitial pneumonia (NSIP) group II, one NSIP group II-III, and one NSIP group II with diffuse alveolar damage. HRCT showed no apparent honeycomb formations in patients diagnosed with NSIP. This is the first report describing NSIP as a pulmonary complication of SSc.

Adult↗
PubMed2001

A rare case of bronchial glomus tumor.

A 48-year-old man was admitted because of bloody sputum in whom a chest computed tomography (CT) scan and fiberoptic bronchoscopy demonstrated a polypoid tumor in the left main bronchus. The tumor was surgically resected, and the pathological and immunohistochemical findings led to diagnosis of the tumor as a bronchial glomus tumor.

Biopsy, Needle↗
PubMed2001

Mucins and immune reactions to mucins in ulcerative colitis.

Ulcerative colitis (UC) is an inflammatory bowel disease of undetermined etiology. Mucins, mainly produced by goblet cells, protect colon cells from various kinds of stress. Alteration in the quality or quantity of mucins may be the cause of the disease. Another possible cause is immune reactions to colonic cells. Anti-MUC1 antibodies were detected in the sera of patients with UC. Antibodies would destroy the colonic cells through antibody-dependent cell-mediated cytotoxicity. We reviewed the significance of mucins as well as humoral and cellular immunity in the pathogenesis of UC.

Antibodies↗
PubMed2001

MUC1 mucin core protein binds to the domain 1 of ICAM-1.

BACKGROUND: MUC1 is aberrantly expressed on a variety of epithelial tumors. We have reported that MUC1 plays important roles in separation from primary site, invasion into the stromal tissue, and protection from immune responses. The aim of this study is to determine the precise binding of MUC1 to intercellular adhesion molecule 1 (ICAM-1) that accelerates the cancer metastasis. METHODS: A cell aggregation assay between MUC1 cDNA transfectants and ICAM-1 expressing cells was employed. An anti-MUC1 antibody, anti-ICAM-1 antibody or synthetic peptide of MUC1 core protein was added to the assay to inhibit the cell aggregation. RESULTS: MUC1 transfectants showed a significantly higher aggregation rate compared to the control cells. This aggregation was further enhanced by the inhibition of O-glycan biosynthesis. It was inhibited by either an anti-MUC1 antibody recognizing the tandem repeat domain of MUC1 core protein or an anti-ICAM-1 antibody identifying domain 1. It was also inhibited by a synthetic MUC1 peptide of 40 amino acids corresponding to two tandem repeats. CONCLUSIONS: The results revealed that a tandem repeat domain of MUC1 mucin core protein binds to domain 1 of ICAM-1, suggesting a potential role of MUC1- ICAM-1 interaction in the metastasis of epithelial tumors.

Animals↗
PubMed2001

Growth hormone prevents Fas-induced apoptosis in lymphocytes through modulation of Bcl-2 and caspase-3.

OBJECTIVE: Growth hormone (GH) has been reported to have a potent effect on the immune system. However, the detailed mechanism of the effect of GH on the immune system has not yet been clarified. This study was designed to investigate the nature of this mechanism. METHODS: In the present study, we investigated the effects of GH on the susceptibility of both human CEM/C7 lymphocytes and human IM-9 lymphocytes to Fas-induced apoptosis. RESULTS: Both cell lines expressed GH receptor mRNA. GH rescued Fas-induced suppression of [(3)H]-thymidine incorporation into each cell line. GH prevented Fas-induced apoptosis in each cell line without changing Fas antigen expression. We next investigated the mechanisms of the prevention of Fas-induced apoptosis, by focusing on intracellular molecules related to the apoptotic signal. Bcl-2 expression was increased by GH treatment in both CEM/C7 and IM-9 lymphocytes. GH also downregulated caspase-3 expression and inhibited activation of caspase-3 in both cell lines. CONCLUSION: These findings suggest that GH regulates the human immune system through inhibition of Fas-induced apoptosis in activated T and B lymphocytes.

Antibodies, Monoclonal↗
PubMed2001

Phosphatidylinositol 3-OH kinase-Akt/protein kinase B pathway mediates Gas6 induction of scavenger receptor a in immortalized human vascular smooth muscle cell line.

The growth arrest-specific gene 6 encodes a secreted protein, Gas6, which was originally identified as the ligand of a receptor, Axl, with tyrosine kinase activity. The class A scavenger receptor (SRA) mediates lipid uptake into cells, leading to the formation of foam cells, an important step in atherogenesis. Although Gas6 induces SRA expression, the underlying mechanism is not clear. In this report, we show that the Gas6-induced expression of SRA was mediated by the phosphatidylinositol 3-OH kinase (PI3-kinase)-serine/threonine kinase (Akt/protein kinase B [PKB]) pathway involving Akt phosphorylation. This pathway was activated by exposure to Gas6. Furthermore, the effect of Gas6 was abrogated by wortmannin, a specific inhibitor of PI3-kinase. We also demonstrated that the constitutively active form of Akt enhanced activity of the SRA promoter but that the dominant-negative mutant of Akt completely abolished the expression of SRA after treatment with Gas6. These results show that the PI3-kinase-Akt/PKB pathway participates in Gas6-induced SRA expression and suggests that the activation of Akt/PKB plays an important role in Gas6-induced atherosclerosis and foam cell formation in human vascular smooth muscle cells.

Androstadienes↗
PubMed2001

The CUP-SHAPED COTYLEDON1 gene of Arabidopsis regulates shoot apical meristem formation.

In higher plants, molecular mechanisms regulating shoot apical meristem (SAM) formation and organ separation are largely unknown. The CUC1 (CUP-SHAPED COTYLEDON1) and CUC2 are functionally redundant genes that are involved in these processes. We cloned the CUC1 gene by a map-based approach, and found that it encodes a NAC-domain protein highly homologous to CUC2. CUC1 mRNA was detected in the presumptive SAM during embryogenesis, and at the boundaries between floral organ primordia. Surprisingly, overexpression of CUC1 was sufficient to induce adventitious shoots on the adaxial surface of cotyledons. Expression analyses in the overexpressor and in loss-of-function mutants suggest that CUC1 acts upstream of the SHOOT MERISTEMLESS gene.

Amino Acid Sequence↗
PubMed2001

Antidiabetic activity of the rhizoma of Anemarrhena asphodeloides and active components, mangiferin and its glucoside.

The antidiabetic activity of the rhizoma of Anemarrhena asphodeloides was investigated in KK-Ay mice, an animal model of genetic type 2 diabetes. The water extract of the rhizoma (AA) (90 mg/kg) reduced blood glucose levels from 570 +/- 29 to 401 +/- 59 mg/dl 7 h after oral administration (p<0.05) and also tended to reduce serum insulin levels in KK-Ay mice. AA-treated KK-Ay mice had significantly reduced blood glucose levels in an insulin tolerance test. Based on these results, the antidiabetic mechanism of AA may be due to decreased insulin resistance. In addition, the active components of AA were confirmed to be mangiferin and its glucoside.

Animals↗