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Biomedical subjects

S Miyake

Publications and source records attributed to S Miyake.

At least 163 records · Page 9Linked to original sources
PubMed1995

Immune responsiveness to inhaled antigens: local antibody production in the respiratory tract in health and lung diseases.

The pulmonary defence mechanism in summer type hypersensitivity pneumonitis induced by Trichosporon cutaneum was investigated. We have studied the antibody response to fungal antigens in sera and bronchoalveolar lavage (BAL) fluids from patients with summer type hypersensitivity pneumonitis, bird fancier's lung, interstitial pneumonia associated with collagen vascular disease (INT-PNE), and from normal volunteers. Antigens extracted from fungi frequently isolated from home environments were used in ELISA to detect IgG and IgA antibodies in sera and BAL fluids. The results of the present study show that antibody titre in the respiratory tract to a variety of fungi from home environments is modulated by ongoing pulmonary inflammation, and that antibody production against inhaled antigens is altered by pulmonary inflammation resulting from diverse pathogenesis. This study concludes that the preexisting pulmonary inflammatory disease alters antibody production in the respiratory tract in response to inhaled fungi, and that the type of alteration depends in part on the etiology of the preexisting disease.

Aerosols↗
PubMed1995

Influence of task demand characteristics on workload and performance.

Two experiments are reported that examined the influence of variation in task demand on performance and workload. The first experiment considered how the manipulation of prior level of task demand affected subsequent workload and performance. The second experiment examined the effects on performance and workload of increments in the level of task demand. Results from the first study indicated that prior level of imposed task difficulty did affect response in a manner consistent with a scaling of workload in relation to previous task conditions. The second study demonstrated the primacy of absolute demand level over increments in that demand as influencing operator response. Overall, our results indicate that workload and performance are sensitive to multiple characteristics of the task and not instantaneous demand level alone. These findings are important in explaining why association and dissociation occur between task demand, operator efficiency, and perceived workload in differing performance contexts. The importance of these findings for the aviation psychologist in assessing pilot and operator workload is articulated.

Adult↗
PubMed1995

Phosphatidylinositol-3 kinase in fission yeast: a possible role in stress responses.

A DNA fragment coding for a part of a putative phosphatidylinositol 3 kinase was cloned from Schizosaccharomyces pombe by cross-hybridization with Saccharomyces cerevisiae VPS34 gene, a yeast homologue of mammalian PI-3 kinase. The clone contained an open reading frame of 797 amino acids but lacked the initiation codon, ATG. The predicted amino acid sequence was homologous to those of S. cerevisiae VPS34 and mammalian PI-3 kinase genes. Disruption of the gene resulted in extremely low levels of PI-3-P and higher levels of PI-4-P, supporting the idea that the gene codes for the PI-3 kinase of S. pombe. The disruptants harbored large vacuoles and were sensitive to stresses such as high temperature or high concentration of monovalent and divalent cations.

Amino Acid Sequence↗
PubMed1995

[Evaluation of anastomosis between intrahepatic or extrahepatic vessels by intra-arterial digital subtraction angiography using carbon dioxide].

Carbon dioxide (CO2) intraarterial subtraction angiography (IADSA) was performed in 31 patients with various hepatobiliary diseases. The injection sites of CO2 were proper hepatic artery (10/31; group A), segmental hepatic artery (18/31; group B), and peripheral inferior phrenic artery (3/31; group C), respectively. In group A, only the third order branches of the portal venous system were visualized anterogradely in 8 of 10 patients. In group B, the microcatheter was placed coaxially through a 5 French guiding catheter at the main arterial supply of the tumor in 7 patients and at the peripheral segmental branch of the hepatic artery in 11 patients. The portal venous system was visualized retrogradely in all of the patients regardless of the injection site. The injected CO2 may flow back into the portal vein through the anastomosis known as the peribiliary or periportal plexus. In group C, not only the portal vein but also the pulmonary artery or pericardial vein were visualized by this method. CO2-IADSA was useful to image the minute communications between the various vessels, which have been not hitherto visualized by iodinated contrast medium.

Adult↗
PubMed1995

[Relationship between regional flow reserve supplied by the great saphenous vein graft and regional left ventricular wall motion: a Doppler guide wire study].

The relationship between regional flow reserve supplied by a great saphenous vein graft and myocardial infarction and anterior wall motion assessed by left ventriculography was studied in 28 patients with no stenosis in the great saphenous vein graft and the peripheral site of the recipient left anterior descending coronary arteries. The proximal segment to the anastomosis was totally or subtotally occluded. The resting graft blood flow velocity was measured using a Doppler guide wire, then 0.56 mg/kg of dipyridamole was injected for 4 minutes intravenously and the resultant increase in graft blood flow velocity was recorded. The regional flow reserve of the anterior wall supplied by great saphenous vein grafts in 11 patients with anterior myocardial infarction (MI group) was significantly lower than that in 17 patients without myocardial infarction (non-MI group) (1.5 +/- 0.3 vs 2.6 +/- 0.7, p < 0.01). The flow reserve supplied by great saphenous vein grafts in 11 patients with normal anterior wall motion was 2.8 +/- 0.7, 10 with hypokinesis 1.9 +/- 0.3, and with akinesis 1.3 +/- 0.3. Reduced anterior wall motion induced a significant decrease in the flow reserve of the anterior wall supplied by the great saphenous vein graft (p < 0.01). The anterior wall motion score of four segments assessed by left ventriculography showed a significant correlation with the flow reserve of the anterior wall supplied by the great saphenous vein graft (y = -0.24 x + 3.7, r = 0.75, p < 0.001). The results show infarcted myocardium was an important influence on coronary flow reserve.

Adult↗
PubMed1995

[Sisters with early onset hereditary dentatorubral-pallidoluysian atrophy of childhood--DNA analysis and clinicopathological findings].

Two sisters were presented, 16 years old and 12 years old, who showed similar clinical courses. They had had mental retardation since early childhood, and then ataxia began. They suffered from astatic and tonic seizures from early school age, which gradually evolved to intractable epilepsies. Spasticity progressed, and they deteriorated both physically and mentally. They revealed photo-sensitivity; convulsions were induced by the flickering of light. They were attacked by myoclonic seizures as well as choreoathetosis, and became bedridden by the latter part of the elementary school age. There were no fruitful results of any kind from the laboratory examinations for metabolic disorders. EEG showed that the epileptic seizure discharges were induced by photic stimulation; there were frequent 3-4 Hz diffuse spike-and-wave short bursts during waking and sleep periods. MRI findings of the elder sister at the age of 16 revealed remarkable diffuse brain atrophy. Gene analysis showed abnormally enlarged DNA fragments localized on the short arm of chromosome 12. This meant expanded CAG trinucleotide repeats. The younger sister died at the age of 12 years. Autopsy findings revealed degeneration of both dentatorubral and pallidoluysian pathways. There were especially remarkable gliosis and neuronal cell loss in the outer segment of globus pallidus, and moderate neuronal cell loss and typical grumose degeneration in the dentate nucleus. The diagnosis of juvenile-type hereditary dentatorubral-pallidoluysian atrophy was compatible with the pathologic findings. This diagnosis will be made possible before death through the understanding of the clinical symptoms and molecular genetics.

Adolescent↗
PubMed1994

Point mutations and allelic deletion of tumor suppressor gene DCC in human esophageal squamous cell carcinomas and their relation to metastasis.

Since tumor suppressor gene DCC exhibits amino acid sequence homology to the neural cell adhesion molecule, there is a possibility that DCC might be related to tumor metastasis. In the present study, we examined 51 cases of primary esophageal carcinomas with regard to point mutations and loss of the DCC gene. We detected point mutations in two cases by screening using polymerase chain reaction-single strand conformation polymorphism analysis. When we determined the sequences, one case with lymph node metastasis showed an ATG (Met) to ACG (Thr) missense mutation in codon 168. Another case showed a CGA (Arg) to GGA (Gly) mutation in codon 201, which might be a polymorphic change, and two other mutations resulting in no amino acid change. We also examined loss of heterozygosity of the DCC gene. Forty-four of the 51 cases (86%) were informative, and among them 10 cases (23%) showed allelic deletion. The further away the lymph node metastasis was from the primary tumor, the higher the frequency of allelic deletions became. We also found allelic deletions in moderately and poorly differentiated squamous cell carcinomas but not in well differentiated ones. These results indicate that alterations of the DCC gene are related to the degree of lymph node metastasis and the degree of differentiation.

Alleles↗
PubMed1994

Mapping of a transcription element critical for expression of the fibroblast growth factor receptor 1 gene.

The fibroblast growth factor receptor 1 (FGFR1) gene has no TATA or CCAAT-elements. To examine its mechanism of expression, we characterized the transcription element of this gene. The basal promoter element was mapped to the 5'-flanking region from -89 to -43. The DNase I protection assay and gel shift analysis revealed that a nuclear protein extracted from FGFR1-expressing cells (NIH3T3 and SC-3), but not from FGFR1-nonexpressing cells (P3U1), could bind to the nucleotide sequence from -62 to -42. The molecular weight of this protein was approximately 100 kDa by Southwestern analysis. In addition, both the promoter activity and the nuclear protein binding activity were markedly impaired by the substitution of two bases within this footprint site. Interestingly, this footprint site appeared to lack the consensus sequence of the currently reported transcription factors. These results indicate that the 5'-flanking region from -62 to -42 plays a pivotal role in FGFR1 gene expression.

3T3 Cells↗
PubMed1994

Primary directional coronary atherectomy for acute myocardial infarction.

The effectiveness of primary coronary angioplasty for acute myocardial infarction (AMI) is now widely recognized. However, the reocclusion rate is as high as 10%. Directional coronary atherectomy (DCA), now used widely in the treatment of stable and unstable angina pectoris, has not been recommended as the primary reperfusion therapy for AMI. This report describes the first preliminary study of primary DCA for AMI without any antecedent thrombolytic therapy or balloon coronary angioplasty. Five patients received primary DCA. The initial results were very good, but further study is necessary to determine the efficacy, particularly the long-term results, of primary DCA in the treatment of AMI.

Atherectomy, Coronary↗
PubMed1994

Identification of collagen and laminin receptor integrins on murine T lymphocytes.

In this study we investigated the receptors by which murine lymphocytes bind to collagen and laminin. To identify the collagen and laminin receptors, we generated three monoclonal antibodies, two of which (HM alpha 1 and HM alpha 2) could inhibit adhesion of activated T cells to collagen and laminin and one of which (HM alpha 6) could inhibit that to laminin. Biochemical studies showed that the antigens recognized by HM alpha 1, HM alpha 2, and HM alpha 6 are the mouse homologues of human VLA-1, VLA-2, and VLA-6, respectively. Finally, we demonstrated that both VLA-1 and VLA-2 contribute to the functional interaction between collagen and activated T cells, since HM alpha 1 and HM alpha 2 specifically inhibited collagen-induced TNF secretion from activated T cells. These results indicate that VLA-1 and VLA-2 play an important role in regulating adhesion and cytokine production of activated T cells.

Animals↗
PubMed1994

Acquisition of color opponent representation by a three-layered neural network model.

This paper discusses color representation in the visual system by analysis of a three-layered neural network model. The model incorporates physiological knowledge of color representation at the sensor level (broad-band trichromatic representation by cones) and the higher level (narrow-band color representation by color-coded cells in V4). We trained the model to perform a mapping between these color representations by the back propagation algorithm and analyzed the acquired characteristics of the hidden units. It turned out that the hidden units learned characteristics similar to those of the color opponent cells found in the visual system. It was concluded that the R-G and Y-B color opponent representations reflect the efficiency of the color representation in the visual system from investigations on the efficiency of color representation in the hidden layer and on the capability of the color recognition task of the model.

Color Perception↗
PubMed1994

Plasma thrombomodulin as a marker of vascular injuries in collagen vascular diseases.

Thrombomodulin, a thrombin receptor on the vascular endothelial cell surface, is released into circulating blood. The plasma concentrations in patients with collagen vascular diseases, including systemic lupus erythematosus (SLE), rheumatoid arthritis, juvenile rheumatoid arthritis, Sjögren's syndrome, systemic sclerosis, polymyositis and/or dermatomyositis (PM/DM), Behçet's disease, and Wegener's granulomatosis, were measured and compared with those of healthy persons. The mean plasma thrombomodulin concentrations in patients with juvenile rheumatoid arthritis, systemic sclerosis, PM/DM, Wegener's granulomatosis, and active states of SLE, rheumatoid arthritis, and Beçhet's disease were significantly higher than those in the control group. Patients with Wegener's granulomatosis showed the highest mean value. The mean values in patients with inactive states of the diseases and Sjögren's syndrome were not significantly different from the values in the control group. In cases of juvenile rheumatoid arthritis, systemic sclerosis, PM/DM, and Wegener's granulomatosis, patients with active interstitial pneumonitis or extensive pulmonary lesions frequently showed higher values of plasma thrombomodulin than those without overt pulmonary involvement. Elevated plasma thrombomodulin values were decreased along with amelioration of the diseases by treatment. These results may indicate that plasma thrombomodulin measurement may be helpful for evaluating vascular injury in patients with collagen diseases.

Adult↗
PubMed1994

Effects of RS-2135, a novel class I antiarrhythmic agent, on sustained ventricular tachycardia after coronary embolization in conscious dogs.

To assess the ability of RS-2135, a novel class I antiarrhythmic agent to suppress ischemia-induced ventricular arrhythmias, we produced myocardial infarction (MI) by introducing a glass bead into the coronary artery of the dog (bead model). Ventricular arrhythmias after coronary embolization were as severe and long-lasting as those that occur after two-stage coronary artery ligation as described by Harris. RS-2135 (1.25 and 2.5 mg/kg intravenously, i.v.) suppressed sustained ventricular tachycardia (SVT) 24 h after coronary embolization in the bead model. The antiarrhythmic effects of i.v. administration of RS-2135 were more potent and more long-lasting than those of lidocaine (5 and 10 mg/kg i.v.), mexiletine (5 and 10 mg/kg i.v.), disopyramide (2.5 and 5 mg/kg i.v.), and flecainide (2.5 and 5 mg/kg i.v.). The antiarrhythmic effects of oral (p.o.) administration of RS-2135 were evaluated 48 h after coronary embolization. RS-2135 (10 mg/kg p.o.) was equipotent to flecainide (10 mg/kg p.o.) and twice as potent as disopyramide (20 mg/kg p.o.) and mexiletine (20 mg/kg p.o.). Onset of antiarrhythmic effects after p.o. RS-2135 was slower than that of other drugs. These data suggest that the bead model is as useful as the Harris model for evaluation of the antiarrhythmic potential of chemicals and that RS-2135, either i.v. or p.o., is effective against SVT after acute MI.

Administration, Oral↗
PubMed1994

Focal hepatocellular necrosis and portal lymphocytic infiltration of the liver in chronic alcoholics: histopathological study of 40 liver biopsies.

Forty liver biopsies of hepatitis B surface antigen negative chronic alcoholics were histologically studied to assess the influence of hepatitis C virus (HCV)-infection. A moderate degree of focal hepatocellular necrosis and/or portal lymphocytic infiltration (FHN-PLI) was observed in 28% of the specimens, being especially prevalent in advanced cases of fibrosis and cirrhosis, and significantly correlated with HCV-infection. Eleven of these cases were examined in detail: HCV-infection was detected in eight and lymphocytic infiltration was apparent in the portal area, accompanied by formation of lymph follicles. The FHN-PLI was ascribed to alcoholic hepatitis in two HCV-negative cases and was concluded to be of unknown etiology in the remaining one HCV-negative case. This study thus indicated that over two-thirds of cases of chronic hepatitis in alcoholics can be attributed to HCV-infection, with the remainder being at least partly related to alcoholic hepatitis. The prevalence of alcohol-induced chronic hepatitis based on immunopathological findings was unclear, but was probably less frequent than previously reported.

Adult↗
PubMed1994

Increment of CD8S6F1 cells in synovial fluid from patients with rheumatoid arthritis.

OBJECTIVE: To investigate the role of CD8 cell subsets in the pathogenesis of rheumatoid arthritis (RA) and the phenotypes of T cells adherent or non-adherent to the target cells (endothelial cells and synovial cells) pre-treated with IL-1 beta. METHODS: The expression of S6F1 on CD8 cells and that of an activation marker on CD8 cells and CD8 cell subsets was evaluated in specimens of peripheral blood and synovial fluid obtained from 15 patients with RA and 10 with osteoarthritis (OA) using a two- or three-colour immunofluorescence method for analysis. RESULTS: The percentage of CD8S6F1 cells among CD8 cells in synovial fluid was significantly greater than that of peripheral blood. Synovial fluid from RA patients had a greater percentage of CD8S6F1 cells compared with either peripheral blood of matched patients or synovial fluid of OA patients. The percentage of CD8HLA-DR cells in synovial fluid was markedly greater than that in paired samples of peripheral blood in patients with RA. In the CD8S6F1 cells from both groups of patients, synovial fluid showed an increased percentage of HLA-DR cells compared with peripheral blood. Similar results were observed in CD8 cells lacking S6F1 expression (CD8S6F1-) from both groups of patients. There was no significant difference in the percentage of HLA-DR cells between CD8S6F1 and CD8S6F1- cell populations in peripheral blood. In contrast with peripheral blood, in synovial fluid of RA patients the percentage of HLA-DR cells in the CD8S6F1 cell population was markedly greater than that in the CD8S6F1- population. However, the percentage of HLA-DR cells in both cell populations was similar in synovial fluid of OA patients. In both the endothelial and the synovial cell adhesion assays, the percentage of CD8S6F1 among CD8 cells and the mean fluorescence intensity of S6F1 antigen on CD8S6F1 cells were significantly greater in the adherent T cell population than that in the non-adherent T cell population. CONCLUSION: These results suggest that increased expression of S6F1 antigen and the increased percentage of HLA-DR cells on CD8 cells in synovial fluid may be responsible for the migration of these cells into inflamed synovial tissues, and for cellular interactions between these cells and synovial cells or the extracellular matrix.

Adult↗