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Biomedical subjects

K Shimada

Publications and source records attributed to K Shimada.

At least 595 records · Page 33Linked to original sources
PubMed1996

Molecular characterization of a novel cancer cell line established from human carcinoma in pleomorphic adenoma (CaPA-4).

A cultured cell line (CaPA-4), derived from an undifferentiated carcinoma in a pleomorphic adenoma of the submandibular gland, was established through xenografted tumors in nude mice. Geneticin treatment eliminated surrounding mouse fibroblasts and yielded enriched tumor cells at an early stage of cell passage. In vitro, the line grew in a cobblestone pattern, revealing its epithelial origin. Chromosomal analysis by Giemsabanding confirmed its human origin, while electron microscopic examination showed its squamous-cell characteristics. CaPA-4 cells stained positive for the c-myc and Ha-ras antibodies. Molecular analysis showed over-expression of both c-myc and Ha-ras mRNA, with point mutation of p53 at codon 248 and of Ha-ras at codon 61. Amplification and rearrangement of the Ha-ras gene were observed; however, no loss of heterozygosity (LOH) of the p53 gene was detected by Southern blotting. This sequence of cancer-related gene activation may represent the malignant transformation from benign pleomorphic adenoma. This report describes the establishment and molecular characterization of this novel cell line from carcinoma in pleomorphic adenoma exhibiting squamous-cell differentiation. This could represent a useful model for investigating the cause of malignant transformation from human salivary-gland mixed tumors.

Adenoma, Pleomorphic↗
PubMed1996

An aggressive therapeutic approach to carcinoma of the body and tail of the pancreas.

BACKGROUND: Prognosis of patients with adenocarcinoma of the pancreatic body and tail is extremely poor. Anatomically, this part of the pancreas is thin, and cancerous invasion to the retropancreatic structures occurs easily. The majority of patients have residual tumor in the retroperitoneal tissues after conventional distal pancreatectomy. METHODS: Between 1962 and 1979, 10 patients with carcinoma of the pancreatic body underwent simple distal pancreatectomy. Between 1980 and 1990, 22 patients including 7 with distant metastasis underwent a more aggressive approach intended to achieve longer survival: distal pancreatectomy with extended dissection of the lymph nodes and adjacent structures, especially into the retropancreatic space. After 1984, intraoperative ŕadiation (IORT) by electron beam and chemotherapy by hepatic infusion plus systemic injection of mitomycin C (MMC) were added for 7 patients without distant metastasis. RESULTS: The 10 patients who underwent pancreatectomy between 1962 and 1979 all died within 20 months after their operations. Conversely, the patients treated with an aggressive approach between 1980 and 1990 survived longer; the 5-year survival rate for 15 patients without distant metastasis was 29%, though the 7 patients with distant metastasis died within 10 months of their operations. There were 4 long term survivors (> or = 5 years); 3 of whom received IORT and chemotherapy with MMC. Invasion to the retropancreatic soft tissues was present in 95% of the resected specimens from the 22 patients. However, invasion to the surgical margin at the posterior surface of the resected specimen was present in only 36% after extended resection of the retropancreatic structures. CONCLUSIONS: Survival improved for this disease after distal pancreatectomy with extended dissection, especially of the retropancreatic structures, adjuvant IORT, and chemotherapy had been performed.

Adenocarcinoma↗
PubMed1996

Shortcut of the photosynthetic electron transfer in a mutant lacking the reaction center-bound cytochrome subunit by gene disruption in a purple bacterium, Rubrivivax gelatinosus.

A mutant lacking the reaction center-bound cytochrome subunit was constructed in a purple photosynthetic bacterium, Rubrivivax gelatinosus IL144, by inactivation of the cytochrome gene. Photosynthetic growth of the C244 mutant strain occurred at approximately half the rate of the wild-type strain. Although mutagenesis resulted in a greatly reduced amount of membrane-bound cytochromes c, illumination induced cyclic electron transfer and the generation of membrane potential in the mutant as observed in the wild-type strain. These findings are consistent with previous observations that the cytochrome subunit is absent in the reaction center complex in some species of purple bacteria and that the biochemical removal of the subunit did not significantly affect the in vitro electron transfer from the soluble cytochrome c to the photosynthetic reaction center. These results suggest that the cytochrome subunit in purple bacteria is not essential for photosynthetic electron transfer and growth, even in those species generally containing the subunit.

Ascorbic Acid↗
PubMed1996

Rat endothelin-converting enzyme-1 forms a dimer through Cys412 with a similar catalytic mechanism and a distinct substrate binding mechanism compared with neutral endopeptidase-24.11.

Endothelin-converting enzyme-1 (ECE-1) is involved in the conversion of big endothelins (big ETs) into endothelins (ETs) and shows sequence similarity with neutral endopeptidase-24.11 (NEP). Unlike NEP, ECE-1 exists as a disulphide-linked dimer. Here we reveal that Cys412 is solely responsible for the dimerization of rat ECE-1. The C412S mutant enzyme, which existed as a monomer, showed no difference in glycosylation level, subcellular localization of clustering structure formation, but showed a higher K(m) and lower kcat for big ET-1 compared with the wild-type enzyme. These results indicate that dimerization of ECE-1 is preferential for effective conversion of big ETs into ETs. In addition, complete loss of activity in the mutants E592Q, E651Q and H716Q confirmed that these residues are responsible for catalytic activity, zinc binding and stabilization of the intermediate during the transition state respectively. In contrast, the catalytic properties of mutant enzymes containing a substitution at Arg129 or Glu752 were not markedly different from those of the wild-type enzyme, suggesting that these residues play only a minor role, if any, in substrate binding, in contrast with their role in NEP.

Amino Acid Sequence↗
PubMed1996

Ischemic stroke and the gene for angiotensin-converting enzyme in Japanese hypertensives.

BACKGROUND: The ACE insertion/deletion (I/D) polymorphism is reported to be associated with myocardial infarction in both whites and Japanese. However, there have been no reports on the association of this polymorphism with stroke in each race. Furthermore, there are some racial differences in the demographics of cardiovascular disease. In Japanese, stroke (especially that which occurs in preexisting hypertension) is more common and coronary artery disease much less common than in whites. We propose that the ACE I/D polymorphism might be associated with hypertensive cerebrovascular disease in Japanese. METHODS AND RESULTS: To study the association between the ACE I/D polymorphism and hypertensive cerebrovascular disease, we identified the ACE I/D genotype in 228 hypertensive and 104 normotensive Japanese subjects. Compared with its frequency (0.31) in the 90 hypertensives without lacunae detected by magnetic resonance imaging, the ACE*D allele frequency was significantly higher (0.47; P<.001) in the 138 hypertensives with silent or clinically overt ischemic stroke, whereas there was no significant difference between its frequency in hypertensives without lacunae and in 104 normotensive control subjects (0.34). The positive association between the ACE I/D genotype and ischemic stroke in hypertensive patients was independent of other risk factors. CONCLUSIONS: We found a positive association between the ACE*D allele and ischemic stroke in Japanese hypertensives in our study. The ACE*D allele may be an independent risk factor for the development of cerebrovascular disease in hypertensive patients.

Adult↗
PubMed1996

Human monocyte-endothelial cell interaction induces synthesis of granulocyte-macrophage colony-stimulating factor.

BACKGROUND: Adhesion of monocytes to the endothelium is an initial step in the early stages of atherosclerosis and inflammation. Granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates a range of functional activities of monocytes, including regulation of monocyte adhesion and induction of cytokine production. We investigated in this study whether CM-CSF synthesis was induced by the direct cell-to-cell interaction between human monocytes and human umbilical vein endothelial cells (ECs). METHODS AND RESULTS: The expressions of GM-CSF mRNA and protein were analyzed by Northern blotting and ELISA, respectively. Coculture of monocytes and ECs induced the high levels of GM-CSF mRNA expression, whereas culture of ECs or monocytes alone or coculture of neutrophils with ECs induced no GM-CSF mRNA expression. A large amount of GM-CSF was secreted into the supernatant upon coculture of monocytes with ECs. The supernatant from the coculture markedly stimulated 02- release in neutrophils, and this effect was significantly inhibited by anti-GM-CSF antibody (Ab). Immunohistochemistry and in situ hybridization revealed that GM-CSF protein and mRNA were clearly detectable in both ECs and monocytes adhered to ECs but not in nonadherent monocytes. The GM-CSF production by the coculture was markedly inhibited by genistein and partially inhibited by Abs against interleukin-1 and tumor necrosis factor-alpha. CONCLUSIONS: The present results indicate that GM-CSF is produced by direct interaction between monocytes and ECs and suggest that GM-CSF produced locally by monocyte-EC adhesive interaction plays an important role in the pathogenesis of atherosclerosis and inflammation by modulating monocyte/macrophage functions in vivo.

Adult↗
PubMed1996

Effects of aspirin on status of thrombin generation in atrial fibrillation.

Aspirin 330/mg/day suppressed platelet function in patients with atrial fibrillation, although it did not affect the increased coagulation activity in these patients. Findings support the premise that anticoagulant therapy is more appropriate than aspirin for the prevention of systemic embolism in patients with atrial fibrillation.

Aged↗
PubMed1996

Dipyridamole enhances interleukin-1beta-stimulated nitric oxide production by cultured rat vascular smooth muscle cells.

We examined whether dipyridamole affected interleukin-1beta-stimulated nitric oxide (NO) production by cultured rat vascular smooth muscle cells. Interleukin-1beta stimulated the production of nitrite and nitrate, stable metabolites of NO, in a dose- and time-dependent manner in vascular smooth muscle cells. Dipyridamole (1-100 mu M) enhanced interleukin-1beta-induced nitrite production in a dose- and time-dependent manner. The mRNA expression of inducible NO synthase was up-regulated by dipyridamole (0.3-10 mu M) treatment in a dose-dependent manner. Both 8-bromo-guanosine 3',5'-cyclic monophosphate (8-bromo-cGMP) and dibutyryl adenosine 3',5'-cyclic monophosphate (db-cAMP) enhanced the nitrite production in the presence of interleukin-1beta. Dipyridamole up-regulated the effect of both 8-bromo-cGMP and db-cAMP on the interleukin-1beta-induced nitrite production. Dipyridamole increased the intracellular cAMP content in the presence of interleukin-1beta (10 ng/ml), but did not affect the intracellular cGMP content. 8R*,9S*,11S*-(-)-9-hydroxy-9-n-hexyloxy-8-methyl-2,3,9,10- tetrahydro-8,11-epoxy-1H,8H,11H-2,7b,11a-triazadibenzo-(a,g)-cy cloocta ++-(c,d,e)-trinden-1-one (KT 5720), a selective inhibitor of cAMP-dependent protein kinase, abolished the enhancement of interleukin-1beta-induced nitrite production by dipyridamole, whereas 8R*,9S*,11S*-(-)-9-methoxy-carbamyl-8-methyl-2,3,9,10-tetrahydro-8,11-ep oxy-1H,8H,11H-2,7b,11a-trizadibenzo-(a,g)-cyclo-octa-(c,d,e)-tr inden-1-one (KT 5823), an inhibitor of cGMP-dependent protein kinase, did not attenuate the enhancement. Furthermore, Rolipram and 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (Ro-20-1724), cAMP-specific phosphodiesterase type IV inhibitors, augmented the interleukin-1beta-induced nitrite production. We concluded that dipyridamole enhanced the interleukin-1beta-induced NO production via an increase in intracellular cAMP content in cultured rat vascular smooth muscle cells.

Animals↗
PubMed1996

Whole saliva dried on filter paper or diagnosis of HIV-1 infection by detection of antibody IgG to HIV-1 with ultrasensitive enzyme immunoassay using recombinant reverse transcriptase as antigen.

Whole saliva samples collected from HIV-1 seropositive subjects by simple spitting without using any devices were dried on filter paper strips, from which filter paper discs of 3-mm diameter were punched out. The eluates of the discs were subjected to the immune complex transfer enzyme immunoassay for antibody IgG to HIV-1 using recombinant reverse transcriptase of HIV-1 as antigen and a two-site enzyme immunoassay for whole IgG. The signals for antibody IgG to HIV-1 and the amounts of whole IgG obtained with one disc per assay tube were 126-290% of those obtained with 1 microliter of whole saliva samples, provided that filter paper strips were treated with nonspecific rabbit serum prior to drying whole saliva samples and that filter paper discs were tested within a few days after drying whole saliva samples. From these results, diagnosis of HIV-1 infection was indicated to be possible with whole saliva samples dried on filter papers, since the diagnosis was previously shown to be possible with 1 microliter of whole saliva samples. The test for HIV-1 infection with whole saliva samples dried on filter papers was suggested to be useful for various purposes.

Acquired Immunodeficiency Syndrome↗
PubMed1996

An epitope on Ki antigen recognized by autoantibodies from lupus patients shows homology with the SV40 large T antigen nuclear localization signal.

OBJECTIVE: Epitopes on Ki antigen were analyzed using synthetic peptides, including KILT, a 16-mer peptide with an amino acid sequence homologous to the SV40 large T antigen nuclear localization signal (SV40 T NLS). METHODS: In addition to KILT, 4 synthetic peptides, all potential epitopes on Ki antigen according to computer analysis, were prepared and tested for reactivity with 49 anti-Ki-positive lupus sera by enzyme-linked immunosorbent assay. RESULTS: Eighteen sera reacted with KILT, but not with other peptides. The reaction of anit-Ki sera with KILT was specifically inhibited by recombinant Ki antigen. Eight of 49 anti-Ki sera reacted with a 7-mer synthetic peptide of SV40 T NLS, and the reaction was specifically inhibited by KILT. CONCLUSION: The 16-mer Ki peptide containing the sequence homologous to the SV40 T NLS is one of the antigenic epitopes recognized by anti-Ki antibodies in lupus sera.

Amino Acid Sequence↗
PubMed1996

Regulation of ICAM-1 expression by inflammatory cytokines in rat mesangial cells.

We investigated the regulation of intercellular adhesion molecule 1 (ICAM-1) expression by the inflammatory cytokines interleukin 1 beta (IL-1), IL-6 and IL-8 in rat mesangial cells by enzyme-linked immunosorbent assay, flow cytometry and Northern blot analyses. ICAM-1 expression on mesangial cells was stimulated significantly by IL-1 beta, but not by IL-6 nor IL-8, in a dose-dependent manner. Levels of ICAM-1 mRNA were very low in unstimulated mesangial cells, while its expression was markedly induced by exposure to IL-1 beta for 3 h. IL-6 and IL-8 showed no effect on ICAM-1 mRNA accumulation. These results demonstrate that IL-1 beta, but not IL-6 nor IL-8, induces ICAM-1 mRNA and protein accumulation in rat mesangial cells.

Animals↗
PubMed1996

Nitric oxide attenuates adhesion molecule expression in human endothelial cells.

Leukocyte adhesion to vascular endothelium is a crucial step in the early stages of atherosclerosis, which may be mediated by the interaction of adhesion molecules expressed on the surfaces of both cell types. In this study, we investigated the effects of nitric oxide (NO) on the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in human umbilical vein endothelial cells (HUVECs). ICAM-1 and VCAM-1 protein and mRNA expression were determined by cellular ELISA and Northern blot analysis, respectively. Both ICAM-1 and VCAM-1 expression were increased markedly by interleukin-1 beta (IL-1 beta). This IL-1 beta-mediated induction of ICAM-1 and VCAM-1 expression was significantly inhibited in the presence of a NO donor 3-morpholino-sydnonimine (SIN-1) in a dose-dependent manner. The inhibitory effect of SIN-1 was abolished in the presence of a NO scavenger haemoglobin, while addition of 8-bromo-cGMP showed no significant effect on IL-1 beta-induced ICAM-1 or VCAM-1 expression. Northern blot analysis showed that IL-1 beta markedly increased ICAM-1 and VCAM-1 mRNA expression, while SIN-1 decreased the accumulation of these transcripts induced by IL-1 beta. These results suggest that NO could prevent the focal adhesion and accumulation of leukocytes through the inhibition of ICAM-1 and VCAM-1 expression in endothelial cells.

Cell Adhesion↗