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Biomedical subjects

M Ishihara

Publications and source records attributed to M Ishihara.

At least 217 records · Page 12Linked to original sources
PubMed1993

Myocardial SPECT and left ventricular performance study using a single Tc-99m teboroxime injection. Comparison with thallium-201 myocardial SPECT.

Myocardial SPECT using teboroxime was compared to thallium SPECT in 26 patients undergoing cardiac catheterization. Agreement between thallium SPECT and teboroxime SPECT for the identification of myocardial segments was 209/235 (89%). A significant correlation was found in 15 patients between the left ventricular ejection fraction by teboroxime first-pass study and the ejection fraction by contrast ventriculography. In nine patients with myocardial infarction and/or multivessel coronary artery disease, the ejection fraction revealed a mean decrease from 0.52 at rest to 0.46 at exercise. Teboroxime makes it possible to perform an exercise first-pass study of left ventricular ejection fraction followed by myocardial perfusion imaging.

Adult↗
PubMed1993

Impaired coronary flow reserve immediately after coronary angioplasty in patients with acute myocardial infarction.

OBJECTIVE: To examine coronary flow reserve immediately after emergency coronary angioplasty in patients with acute myocardial infarction. DESIGN: A 3 F coronary Doppler catheter was used to measure coronary blood flow velocity in the infarct artery and in the non-infarct artery. Maximal hyperaemia was produced by 10 mg of intracoronary papaverine and coronary flow reserve was calculated. PATIENTS: 11 patients with acute myocardial infarction undergoing both emergency coronary angioplasty (4.7 (3.6) h after the onset of chest pain (mean (SD))) and at follow up catheterisation 16 (4) days after angioplasty. SETTING: Hiroshima City Hospital. RESULTS: There was no stenosis of > or = 50% in the coronary artery of interest. Immediately after coronary angioplasty the mean (1 SD) coronary flow reserve of the infarct artery was significantly less than that of the non-infarct artery (1.4 (0.4) v 2.8 (0.8), p < 0.001). At follow up catheterisation the coronary flow reserve of the infarct artery increased almost to the value of the non-infarct artery (2.8 (1.2) v 3.1 (0.8) p = NS). CONCLUSION: The coronary flow reserve in the infarct region was severely impaired immediately after reperfusion, even with a widely patent infarct artery. This could restrict the beneficial effects of reperfusion therapy, especially when there is a severe residual stenosis.

Adult↗
PubMed1993

Impaired immunity in obesity: suppressed but reversible lymphocyte responsiveness.

Although obese people have been reported to have a higher incidence of infections and some types of cancer, the immunocompetence of obese subjects remains poorly understood. To investigate whether obesity affects immunity, we studied obese subjects (BMI > 30 kg/m2) whose health was uncomplicated by any other disorder, including hyperglycemia. We compared mitogen-induced blastogenic response of peripheral blood lymphocytes in 34 obese subjects (mean +/- s.e. BMI: 38.4 +/- 2.0 kg/m2) and 35 non-obese controls (BMI: 21.3 +/- 0.4 kg/m2) who were matched for age and sex. The effects of weight reduction were also evaluated in 19 obese persons (BMI: 36.4 +/- 1.8 kg/m2) on a very low calorie diet. Mean (+/- s.e.) intracellular incorporation of [3H]-thymidine, on stimulation of T lymphocytes with either phytohaemagglutinin (PHA) or concanavalin A (Con A), and B lymphocytes with pokeweed mitogen, was significantly diminished in obese subjects compared to non-obese controls (47552 +/- 6917 vs. 83720 +/- 6252 cpm, P < 0.001; 30301 +/- 6018 vs. 45942 +/- 3723 cpm, P < 0.05; 13669 +/- 2971 vs. 23735 +/- 2048 cpm, P < 0.01, respectively). After weight reduction (BMI: 27.8 +/- 1.2 kg/m2), the mean T lymphocyte responses to PHA and Con A were increased significantly vs. baseline (98404 +/- 2444 vs. 50337 +/- 9516 cpm, P < 0.05 and 69523 +/- 15480 vs. 36695 +/- 8006 cpm, P < 0.05, respectively). Depressed blastogenesis of B lymphocytes was also augmented but was not statistically significant. The results suggest that obese subjects have underlying immune impairment in responsiveness of lymphocytes and that these impairments are reversible with adequate weight reduction.

Adult↗
PubMed1992

Selection of COS cell mutants defective in the biosynthesis of heparan sulfate proteoglycan.

A simple procedure using human basic fibroblast growth factor (FGF) was utilized for the selection of COS cell mutants with defects in the biosynthesis or expression of heparan sulfate proteoglycan (HSPG). Our approach was based on the strong binding affinity exhibited by COS cells to human basic FGF that had been adsorbed to plastic dishes. Cell binding to basic FGF could be inhibited by heparin and heparan sulfate (HS), but not by chondroitin sulfate, dermatan sulfate, keratan sulfate, or hyaluronic acid, suggesting that the cell binding involved an interaction between basic FGF and cell surface heparin-like molecules. COS cells were treated with ethyl methanesulfonate and four stable mutants were subsequently isolated that did not bind strongly to basic FGF adsorbed to plastic. These mutants cell lines (CM-2, CM-8, CM-9, and CM-15) exhibited significantly reduced 35SO4 incorporation into HS (40-70% depending on the cellular pool analyzed). In one of these cell lines, CM-15, the incorporation of [6-3H]glucosamine into HS was unaltered, suggesting that the extent of oligosaccharide polymerization was equivalent to that observed for the wild-type cells. Structural analysis revealed that N-sulfated glucosamine residues were present much less frequently in HS derived from these cells as compared with that derived from wild-type cells. Furthermore, CM-15 was found to be three-fold deficient in HS N-sulfotransferase activity, but contained wild-type levels of HS O-sulfotransferase activities.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Protein kinase C-dependent and -independent actions of a potent protein kinase C inhibitor, staurosporine.

12-O-Tetradecanoylphorbol 13-acetate (TPA), an activator of protein kinase C (PKC), induced ornithine decarboxylase (ODC) in primary cultured mouse epidermal cells. Staurosporine, a potent protein kinase C inhibitor, also induced ODC activity. Both TPA- and staurosporine-caused ODC inductions were markedly suppressed in the PKC-down-regulated cells. Another PKC inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), inhibited both TPA- and staurosporine-caused ODC inductions. H-7 by itself never induced ODC activity. Under our experimental conditions, staurosporine induced no detectable phosphorylation of endogenous proteins. TPA induced a translocation of PKC from cytosol to membrane whereas an optimal concentration of staurosporine to induce ODC did not induce an obvious translocation of PKC. Indomethacin, a cyclooxygenase inhibitor, inhibited staurosporine-caused ODC induction, but not TPA-caused ODC induction. Staurosporine induced specific morphological changes of epidermal cells both in normal and in PKC-down-regulated cells. These results indicate that staurosporine induces ODC activity in a PKC-dependent manner and morphological changes possibly through a PKC-independent mechanism. The mechanism of ODC induction caused by staurosporine may be in some way different from that caused by TPA.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

The binding specificity of normal and variant rat Kupffer cell (lectin) receptors expressed in COS cells.

A receptor uniquely found on the surface of rat Kupffer cells was shown previously to bind oligosaccharides terminating in galactose, N-acetylgalactosamine, and fucose. To analyze further the binding specificity of the receptor, receptor-mediated adhesion of transfected COS cells to immobilized glycolipids of known structure was measured. The glycolipid Gb4Cer (GalNAc beta 1-3Gal alpha 1-4Gal beta 1-4Glc beta 1Cer) was the best ligand. Gb5Cer (GalNAc alpha 1-3GalNAc beta 1-3Gal alpha 1-4Gal beta 1-4Glc beta 1Cer) and LacCer (Gal beta 1-4Glc beta 1Cer) bound more weakly (five times less than Gb4Cer) and Gb3Cer (Gal alpha 1-4Gal beta 1-4Glc beta 1Cer), and g3Cer(GalNAc beta 1-4Gal beta 1-4Glc beta 1Cer) bound even more weakly (60 times less than Gb4Cer). Gangliosides did not support adhesion of transfected cells. The adhesion of COS cells transfected with plasmids encoding variants of the receptor was also examined. In each variant, either tryptophan 498 or 523, which are conserved in most C-type lectins, was replaced by one of several amino acids. Variants that retained binding activity had the same specificity as the normal receptor. Differences between variants were noted, however, in maximal levels of adhesion and these differences correlated with altered expression of the receptor variants in COS cells.

Acetylgalactosamine↗
PubMed1992

A cell-based assay for evaluating the interaction of heparin-like molecules and basic fibroblast growth factor.

A simple panning procedure that allows for the evaluation of interactions between various heparin-like molecules and basic FGF has been developed. This assay measures the ability of compounds to inhibit the interaction of transfected human lymphoblastoid cells, UC 729-6 (UC cells), expressing hamster syndecan and basic FGF-coated plastic plates. The transfected cells bind rapidly to basic FGF-coated plates while the control cells do not bind well. Binding of the transfected cells to basic FGF was inhibited by heparin and heparin sulfate (HS), but not by chondroitin sulfate, dermatan sulfate, keratan sulfate, and hyaluronic acid. There was little inhibition of binding by chemically modified heparin such as completely desulfated, N-acetylated heparin, completely desulfated, N-sulfated heparin, and N-desulfated, N-acetylated heparin. These results suggested that both the N-sulfate and O-sulfate groups of heparin are required for binding to basic FGF. In addition, inhibition by oligosaccharides derived from depolymerized heparin increased with fragment size; partial inhibition was observed with oligosaccharides as small as hexamers. The biochemical basis for the binding of transfected cells to basic FGF was established by showing a significant increase of 35SO4 incorporation into HS. In particular, the level of 35SO4-HS in the trypsin-releasable (cell surface) pool increased fivefold. This increase was accounted for by demonstration of the presence of HS on immunoprecipitated syndecan from the transfected cells.

Animals↗
PubMed1992

Comparison of thallium-201 and technetium-99m teboroxime myocardial single photon emission tomography with coronary arteriography.

Myocardial single photon emission tomography (SPET) using technetium-99m teboroxime (teboroxime) was studied and the results compared with those of thallium-201(thallium) SPET and coronary arteriography in 19 patients. Resting teboroxime SPET was performed initially. Two hours later, exercise teboroxime SPET was performed. Exercise ergometer tests for both teboroxime and thallium were carried out in a supine position. The levels of exercise achieved for both tests were similar. Agreement for the identification of myocardial segments between thallium SPET and teboroxime SPET was 147/171(86%) (NS). When a significant stenosis was defined as greater than or equal to 75% or greater than or equal to 50%, agreement between two radiopharmaceuticals for the detection of diseased vessels was 89% (NS, k = 0.601) or 88% (NS, k = 0.713), respectively. In only 2/19 cases were inferior and posterior segments (3/171) difficult to interpret in teboroxime SPET due to hepatic activity. Thus, teboroxime SPET with a short data acquisition time resulted in a rapid completion for each study and had a good correlation with thallium SPET.

Adult↗
PubMed1992

Effects of intraaortic balloon pumping on coronary hemodynamics after coronary angioplasty in patients with acute myocardial infarction.

It has been reported that intraaortic balloon pumping can prevent reocclusion after coronary angioplasty for acute myocardial infarction. The speculated mechanism has been the production of markedly enhanced diastolic coronary perfusion pressure; however, most studies have reported that intraaortic balloon pumping has little effect on coronary blood flow. To assess the effectiveness of this procedure, we studied 12 patients with acute anterior myocardial infarction who were undergoing coronary angioplasty and intraaortic balloon pumping. After successful angioplasty, coronary blood flow velocity was measured with a coronary Doppler catheter before and during intraaortic balloon pumping. Although mean coronary blood flow velocity was unchanged, intraaortic balloon pumping increased peak coronary blood flow velocity from 34.6 +/- 5.0 cm/sec (mean +/- SEM) to 46.7 +/- 5.8 cm/sec (p < 0.005). Such an increase in peak coronary blood flow velocity seemed to be a mechanism by which intraaortic balloon pumping could prevent reocclusion after coronary angioplasty for acute myocardial infarction.

Angioplasty, Balloon, Coronary↗
PubMed1992

Necrotic colitis associated with Entamoeba histolytica infection in a cat.

A 3-year-old Persian cat developed bloody diarrhoea. On histological examination, a marked necrotic colitis with a large number of invading protozoan parasites was observed. The protozoan was identified as Entamoeba histolytica by light and electron microscopy. This is the first report describing spontaneous amoebiasis in cats.

Animals↗
PubMed1992

Monoclonal anti-melanoma antibodies IKH-1 and IKH-2 which work on formalin-fixed, paraffin embedded tissues: characterization, clinical trials and comparative studies with HMB-45.

Mouse monoclonal antibodies (MoAbs), IKH-1 and IKH-2, were produced against cloned human melanoma cells, KHm-6, which were cultured with 12-O-tetradecanoylphorbol-13-acetate (TPA) and processed by formalin fixation and alcohol dehydration (FFAD). According to the biochemical analysis, antigenic substances which reacted with IKH-1 were 34.0-60.0 kDa glycoproteins, and those which reacted with IKH-2 were 33.5, 34.5 and 36.0 kDa glycoproteins. Immunoelectron microscopy revealed that reaction products of IKH-1 were seen in some membranous vesicles, premelanosomes and cell membrane of TPA-treated KHm-6 cells, while IKH-2 recognized only premelanosomal structures. Immunohistochemical tests revealed that IKH-1 and IKH-2 have a high sensitivity (94.0% and 85.0%, respectively) to formalin-fixed, paraffin-embedded (FFPE) tissue sections of malignant melanomas. IKH-1 had a high specificity and IKH-2 and 100% specificity to FFPE tissue sections of melanocytic lesions.

Animals↗
PubMed1992

Increase of serum somatomedin C in hyperthyroid patients with pregnancy.

In thyrotoxic women with pregnancy, serum somatomedin C (SmC) concentration was markedly elevated (mean +/- SD 13.57 +/- 4.66 U/ml) compared to thyrotoxic women without pregnancy (1.24 +/- 1.09 U/ml), non-pregnant euthyroid women previously treated for hyperthyroidism (0.87 +/- 0.30 U/ml), normal subjects with pregnancy (6.08 +/- 3.36 U/ml) and pregnant euthyroid women previously treated for hyperthyroidism (5.98 +/- 1.52 U/ml). Since SmC/growth hormone ratio was significantly more in thyrotoxic pregnant women than in normal pregnant women and euthyroid pregnant women previously treated for hyperthyroidism, and since human placental lactogen (HPL), human chorionic gonadotropin (HCG) and prolactin (PRL) do not crossreact with SmC antibody, it is suggested that excess thyroid hormone during pregnancy results in excessive hepatic somatomedin C production.

Adult↗
PubMed1992

Cytokeratin polypeptide profile of Merkel cells in human fetal and adult skin: difference of expression of cytokeratins in epidermal and dermal Merkel cells.

The origin of Merkel cells is uncertain, although current evidence by immunohistochemical keratin marker studies favors an epidermal derivation. We studied the expression of keratin species in Merkel cells of human fetus and adult using 19 anti-keratin antibodies. Epidermal and dermal Merkel cells contained not only simple epithelium-type but also some stratified epithelium-type keratins. Interestingly, expression of some keratins was different between epidermal and dermal Merkel cells, for example, AN3 (50, 58 kD) and CKB1 (50 kD) recognized epidermal Merkel cells, but not dermal Merkel cells. These results suggest that surrounding keratinocytes influence the expression of cytokeratins in Merkel cells or that dermal Merkel cells undergo a modification from keratin-producing epidermal Merkel cells to a more neural cell type by the association with nerve endings in the upper dermis. On the other hand, certain cytokeratin polypeptides recognizable with Ks19.1 (40 kD), CK5 (45 kD), and CAM5.2 (52.5 kD) were expressed in both epidermal and dermal Merkel cells. The expression of simple epithelium-type keratins in Merkel cells remained even after the epidermal basal cells gradually lost their expression.

Adult↗
PubMed1992

Centrifugal lipodystrophy of the face mimicking progressive lipodystrophy.

We report a Japanese boy with centrifugal lipodystrophy. The initial lesion developed on the forehead as an area of erythema which showed centrifugal spread and central fading to leave a residual depression. Three years later, similar erythematous lesions appeared on the cheeks, and he developed a cadaverous appearance. A central depression on the upper trunk was surrounded by an erythematous border and there was right cervical lymphadenopathy. Histological examination revealed inflammatory changes in the subcutaneous fat. Although this patient showed the characteristics of both centrifugal and progressive lipodystrophy (partial lipodystrophy), we consider that he has centrifugal lipodystrophy of the face because of the overall features of the lesions.

Facial Dermatoses↗