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Biomedical subjects

M Murase

Publications and source records attributed to M Murase.

At least 37 records · Page 2Linked to original sources
PubMed1999

Characterization of CD4+ CD8alphaalpha+ and CD4-CD8alphaalpha+ intestinal intraepithelial lymphocytes in rats.

Intestinal intraepithelial lymphocytes (i-IEL) of aged rats comprise CD4+CD8alphaalpha+ and CD4-CD8alphaalpha+ T cells expressing TCR alphabeta. In the present study, we compared characteristics between CD4+CD8alphaalpha+ and CD4-CD8alphaalpha+ i-IEL, which were purified by a cell sorter from the i-IEL of 6-month-old Lewis rats. Most of the CD4+CD8alphaalpha+ i-IEL were of the CD44(hlgh) phenotype, while CD4-CD8alphabeta+ i-IEL were CD44(low). Vbeta usage in the CD4-CD8alphaalpha+ i-IEL was much diversified, while CD4+CD8alphaalpha+ i-IEL showed a skewed Vbeta repertoire. The CD4+CD8alphaalpha+ i-IEL but not the CD4-CD8alphaalpha+ i-IEL proliferated in response to syngeneic spleen cells, which was partially inhibited by addition of anti-MHC class I mAb. The CD4+CD8alphaalpha+ i-IEL produced IFN-gamma and IL-2 but no IL-4 or transforming growth factor (TGF)-beta in response to syngeneic spleen cells, while CD4-CD8alphaalpha+ i-IEL produced abundant levels of TGF-beta but no IL-2, IFN-gamma or IL-4. CD4+CD8alphaalpha+ i-IEL proliferated in response to exogenous IL-2 but not to IL-15, while CD4-CD8alphaalpha+ i-IEL could respond to IL-15 as well as IL-2. These results suggest that a significant fraction of CD4+CD8alphaalpha+ i-IEL belongs to Th1-type T cells capable of responding to self-MHC class I, while CD4-CD8alphaalpha+ i-IEL are a unique population with a diversified Vbeta repertoire that respond to IL-15 in rats.

Aging↗
PubMed1999

[In vitro antibacterial activities of carbapenems against clinical isolates].

Antibacterial activities of four carbapenems, imipenem, panipenem, meropenem, and biapenem, were determined using 353 strains belonging to 18 bacterial species which were isolated from clinical materials at Ehime University Hospital. The MIC values of these carbapenems against MRSA were widely distributed between 0.1 and 100 micrograms/ml, and MIC90 values of these 4 carbapenems were 25-50 micrograms/ml. Any of these carbapenems prevented the bacterial growth of enterobacteriaceae of 8 bacterial species excluding S. macrescens at concentrations of 1 microgram/ml or less. The MIC values against P. aeruginosa showed relatively wide distribution, being 0.39-25 micrograms/ml for imipenem, 0.2-25 micrograms/ml for panipenem, 0.1-12.5 micrograms/ml for meropenem, and 0.2-12.5 micrograms/ml for biapenem. From those results, it was confirmed that any of the carbapenems tested had a wide antibacterial spectrum and strong antibacterial activities.

Bacteria↗
PubMed1998

[Coronary artery bypass grafting in cases with poor left ventricular function].

From January 1987 through June 1992, 18 patients with poor left ventricular function (left ventricular ejection fraction [LVEF] less than 0.3) underwent elective isolated primary coronary artery bypass surgery. The mean age was 56.4 years (range, 46 to 72 years), and 15 were males and 3 were females. Mean pre-operative LVEF measured by ventriculography was 0.26 +/- 0.03 (range, 0.19 to 0.30). Sixteen patients (88.9%) had a prior myocardial infarction and 9 (50%) had a history of congestive heart failure. Complete revascularization was the goal for all patients, and the mean number of bypass grafts was 3.0 +/- 0.8 per patient. The left anterior descending coronary artery (LAD) was revascularized in all patients. There were no operative deaths. Post-operative LVEF improved significantly from 0.26 +/- 0.03 to 0.42 +/- 0.11 (p = 0.0002), and the regional left ventricular wall motion improved in the diaphragmatic and posterobasal regions (p < 0.01). The patency of the grafts was 93.9% in all, and 100% for LAD. The mean follow-up period was 77 months, and the overall actuarial survival rate was 88.9% at 10 years. During follow-up periods, two patients died of congestive heart failure (CHF), and two required three rehospitalizations because of CHF. The overall cardiac event free rate was 75.8% at 10 years. In patients with poor left ventricular function, surgical revascularization can be performed safely, but congestive heart failure sometimes occurs during follow-up periods and may be the cause of death. Therefore alternate forms of therapy such as cardiac transplantation and/or TMLR should be considered in selected patients.

Aged↗
PubMed1998

Improved efficiency of energy transfer to external work in chronic cardiomyoplasty based on the pressure-volume relationship.

OBJECTIVE: Cardiomyoplasty is a surgical procedure to support the failing heart, in which a burst-stimulated latissimus dorsi muscle flap is transposed and wrapped around the ventricles. The effect of dynamic cardiac compression, implemented as cardiomyoplasty, on left ventricular performance remains controversial; the mechanism by which clinical symptoms are improved remains unclear. To investigate the mechanism for improvement of patients' symptoms, it is important to evaluate the effects of cardiomyoplasty on left ventricular energetics and on left ventricular systolic and diastolic function. We therefore evaluated the efficiency of energy transfer from the native pressure-volume area to external work under conditions of 1:3 skeletal muscle burst pacing in an animal model with chronic heart failure. METHODS: In seven Merino-Wether sheep, cardiomyoplasty was performed after stable heart failure was induced by staged coronary embolizations (ejection fraction < 35%). Hemodynamic assessment including the assessment of the pressure-volume relationship was performed 8 weeks after cardiomyoplasty when the latissimus dorsi muscle was fully trained. Instantaneous left ventricular pressure and volume were measured with a catheter-tipped manometer and a conductance catheter during steady-state conditions and after a transient inferior vena cava occlusion. The effect of dynamic cardiac compression on left ventricular systolic function was assessed by comparing pre-assisted and assisted beats and on diastolic function by comparing assisted and post-assisted beats. RESULT: The slope of the end-systolic pressure-volume relationship decreased by 30.5% +/- 27.8% (p = 0.02) during assisted beats. However, left ventricular pump performance improved by increasing stroke volume and external work by 35.9% +/- 36.0% (p = 0.03) and 9.7% +/- 6.8% (p = 0.03), respectively, resulting in a reduction of the volume intercept. As a result, the end-systolic pressure-volume relationship shifted to the left. The efficiency of energy transfer from the native pressure-volume area to the overall external work improved by 7.6% +/- 8.2% (p = 0.04). Cardiomyoplasty did not affect the time constant of left ventricular isovolumic pressure decline or the maximal rate of pressure decay, which suggested that cardiomyoplasty did not affect left ventricular relaxation. CONCLUSIONS: Dynamic cardiac compression in the form of cardiomyoplasty enhanced left ventricular pump performance without interrupting left ventricular filling. The ratio of energy transfer from the native pressure-volume area to the overall external work suggests a myocardial oxygen-sparing effect of cardiomyoplasty.

Animals↗
PubMed1998

Everting closure for interrupted aortic arch, ventricular septal defect, and severe subaortic stenosis.

Interrupted aortic arch with ventricular septal defect in the neonate is sometimes complicated by severe subaortic stenosis from posterior deviation of the infundibular septum. We have developed a novel approach to the treatment of this condition. The infundibular septum is penetrated from the right-ventricular side to the left-ventricular outflow tract. It is compressed with patch fixation. The lower margin of the infundibular septum is everted. Three consecutive neonates were treated. The smallest diameters of the left-ventricular outflow tract were 3,4, and 2.5 mm. All patients survived the operation and were discharged from the hospital. They remained well 2 to 7 years after the repair and were in normal sinus rhythm without a left bundle branch block or any significant pressure gradient between the upper and lower extremities. Follow-up two-dimensional and Doppler echocardiography demonstrated no residual shunt, no left-ventricular outflow-tract pressure gradient, and no aortic regurgitation. This technique provides effective widening of the left-ventricular outflow tract, and is more safely and easily performed than conventional methods.

Aorta↗
PubMed1998

Study of rapidity and quality for the VITEK susceptibility cards with 45 wells.

VITEK 45 wells Card was evaluated. Recent clinical isolates of gram-positive cocci (107) and gram-negative bacilli (179) were antimicrobial susceptibility testing by VITEK system in comparison with MIC-2000 system. The antimicrobial susceptibility results were available within of 8 h for gram-positive cocci without a part of MRSA. Enterobac-teriaceae were available within of 8 h and Pseudomonas aeruginosa were from 8 to 11 h. The antimicrobial susceptibility data had disagreement of 60% with EM, 46% with CLDM for Enterococcus faecium, 50% with CMZ for Citrobacter freundii, and 71% with CTM for Morganella morganii, whereas it was satisfactory agreement of 97.5% for gram-positive cocci and 98.2% for gram-negative bacilli. In using this procedure it was possible to provide accurate and rapid results of anti-microbial susceptibility tests for all organisms.

Enterobacteriaceae↗
PubMed1998

Hemofiltration removes bradykinin generated in the priming blood in cardiopulmonary bypass during circulation.

After induction of hemofiltration for the hemic prime of a cardiopulmonary bypass, the initial drop in blood pressure disappears, and postoperative edema rarely occurs. We have suspected that bradykinin, a strong vasodilator generated through the activation of factor XII, prekallikrein, and high molecular weight kininogen was removed by ultrafiltration. We examined the changes in the activities of plasma-factor XII, prekallikrein, high molecular weight kininogen and in the levels of bradykinin in the priming blood using red cell concentrates before and after hemofiltration, and evaluated the effectiveness of hemofiltration. Ten circuits were used, and ten sets of blood samples were collected from red cell concentrates, the priming blood before hemofiltration, after hemofiltration, and the filtrate. During circulation in the circuit, factor XII, prekallikrein and high molecular weight kininogen were completely consumed and a large amount of bradykinin was generated, but it was filtered well by ultrafiltration. Factor XII, prekallikrein and high molecular weight kininogen could be activated through the dilution of red cell concentrates during the priming and contact with the circuits. Because bradykinin is the most potent vasodilator, increasing microvascular permeability and relating to several other inflammatory mediators, the removal of bradykinin generated from factor XII, prekallikrein and high molecular weight kininogen is very significant in the prevention of non-specific inflammatory reactions during and after open-heart surgery.

Bradykinin↗
PubMed1998

A case successfully treated by conservative management for mediastinitis and infected composite graft due to methicillin-resistant coagulase negative staphylococcus.

A 72 year-old man underwent a Bentall procedure for aortic regurgitation secondary to annulo-aortic ectasia and ascending aortic aneurysm. On the 11th postoperative day, the C-reactive protein (CRP) level and white blood cell (WBC) count rose. Echocardiography and a computed tomographic scan showed the appearance of pericardial effusion. A diagnosis of mediastinitis and composite graft infection was made, and mediastinal drainage and irrigation were performed. Methicillin-resistant coagulase negative staphylococcus (MRCNS) was identified as the causative organism. Vancomycin, arbekacin and minocycline were used intravenously. Additionally, a continuous mediastinal irrigation was performed through the chest tubes. CRP level and WBC count were gradually reduced to normal range. He has now been free from signs of infection for more than 3 years. Because MRCNS is considered less virulent than methicillin-resistant Staphylococcus aureus, mediastinitis and composite graft infection due to MRCNS might be treatable by such conservative therapy even in patients with prosthetic implants. Since MRCNS often becomes ubiquitous, preventing infections by strict attention to asepsis is important.

Aged↗
PubMed1998

[Lipid peroxide and antioxidants in the elderly].

Aging is associated with changes in physical characteristics and decline of many physiological functions. The aging process have been described by various theories, in particular the free radical theory of aging has received widespread attention. It has been accepted that the oxidative stress or damage induced by free radicals is related to aging. In this study, we determined the serum concentration of lipid peroxide and antioxidant as biomarker for aging. Healthy subjects were classified into 3 groups, elderly (65-), middle-aged (40-64) and young group (20-39). Findings in the elderly were as follows: 1. Lipid peroxides in the elderly group were significantly higher than those in the young group. 2. Preventive antioxidant concentrations of superoxide dismutase, glutathione peroxidase and albumin were lower than those in the young group, but ceruloplasmin values increased and catalase activity was unchanged. 3. The total antioxidant capacity of serum was slightly decreased. 4. Superoxide generation by neutrophils while resting was significantly higher in the young group.

Adult↗
PubMed1998

[A feature of hematological findings in myelodysplastic syndromes].

Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis in one or more hematopoietic lines with abnormal morphology and peripheral blood cytopenia. Primary MDS are more common in elderly patients and rare in children and young adults. The diagnosis of MDS in patients with unexplained cytopenias requires careful morphologic evaluation of both the peripheral blood and bone marrow cells. To examine which abnormalities detected by routine examination suggest MDS, we analyzed the hematological findings of peripheral blood in seventy-six cases of MDS. Anemia (> 60%), leukopenia (> 40%), thrombocytopenia (> 70%) as well as blast (> 40%) were often found. The prevalence of MDS was relatively high in patients with morphological abnormalities such as elliptocyte, dacryocyte, erythroblast, pseudo-Pelger-Huet anomaly, decreased secondary granules and giant platelets. Careful attention should be paid to these findings especially elderly patients, since these may provide clues to the diagnosis of MDS.

Adult↗
PubMed1997

Blood concentrations of G-CSF and myelopoiesis in patients undergoing aortocoronary bypass surgery.

The pattern of changes in leukocyte counts and the blood concentration of G-CSF were observed in 15 patients undergoing aortocoronary bypass surgery. Myelopoietic function was assessed by examining the myelogram and performing flow cytometry to identify human leukocyte differentiation antigens on bone marrow aspirates obtained from the sternum when opening and closing the sternotomy. The blood concentration of G-CSF increased gradually after removal of the aortic cross clamp and peaked on the first postoperative day (232 +/- 98 ngml). The white blood cell count also increased during the operation and peaked on the second postoperative day, demonstrating a threefold increase (15,800 +/- 2700). Granulocytes represented most of the increase, while lymphocytes and monocytes showed no significant changes. The myelogram showed that the percentages of myeloblasts, promyelocytes, and metamyelocytes did not change; however, the percentage of myelocytes increased significantly during surgery (14.0 +/- 2.5% vs. 17.3 +/- 3.5%, p < 0.05). The number of mature myelocytes (LFA-1 beta and Leu-15 positive) decreased significantly (p < 0.01 and p < 0.05) during surgery. With the two-color method, the ratio of immature myelocytes (MCS-2 negative and Leu-15 negative) increased significantly (p < 0.01). The ratio of myeloblasts (Leu-11 and HLA-DR positive) and the ratio of stem cells (CD 34 and MY-9 positive) did not increase significantly during the operation. G-CSF concentrations increase substantially during aortocoronary bypass surgery and may be responsible for the rise in granulocyte and total leukocyte counts, as well as for the increase in immature myelocytes seen on bone marrow examination.

Aged↗
PubMed1997

Treatment of empyema by transposition of contralateral lower trapezius flap.

We report the successful treatment of bronchopleural fistula and empyema using transposition of a contralateral lower trapezius musclocutaneous flap, which provided immediate obliteration of the middle-back empyema cavity. This technique is easy to perform without any intraoperative change of position and with little postoperative impairment of the back and shoulder movement.

Bronchial Fistula↗
PubMed1997

Body temperature influences regional tissue blood flow during retrograde cerebral perfusion.

OBJECTIVE: This study compared the cerebral microcirculation during retrograde cerebral perfusion with that during antegrade cardiopulmonary bypass under normothermic and hypothermic conditions. METHODS: Brain tissue blood flow was measured with the hydrogen-clearance and colored microsphere (15 and 50 microns) methods during antegrade cardiopulmonary bypass and retrograde cerebral perfusion. Measurements were performed during normothermia (37 degrees C), moderate hypothermia (28 degrees C) and deep hypothermia (20 degrees C) in groups of mongrel dogs (n = 8). RESULTS: During antegrade cardiopulmonary bypass, the microsphere method showed a significant decrease in cerebral blood flow as body temperature decreased (40.1 +/- 20.8 ml/min/100 gm at 37 degrees C, 16.2 +/- 18.0 ml/min/100 gm at 20 degrees C with 50 microns microspheres) At 20 degrees C, the cerebral blood flow measured with the 15 microns microspheres was significantly lower than that assessed with the hydrogen-clearance method (11.3 +/- 7.0 vs 24.8 +/- 7.0 ml/min/100 gm). During retrograde cerebral perfusion, the microsphere method also showed a significant decrease in cerebral blood flow with cooling. At 37 degrees C, the cerebral blood flow measured with the 15 microns microspheres (0.8 +/- 0.7 ml/min/100 gm) was significantly lower than that assessed with the hydrogen-clearance method (10.1 +/- 3.5 ml/min/100 gm). At both 28 degrees and 20 degrees C, the hydrogen-clearance method showed significantly higher cerebral blood flow (10.1 +/- 5.8 and 8.2 +/- 3.7 ml/min/100 gm) than did the 50 microns microspheres (1.8 +/- 0.6 and 1.0 +/- 0.8 ml/min/100 gm) and 15 microns microspheres (0.23 +/- 0.14 and 0.18 +/- 0.15 ml/min/100 gm). CONCLUSION: (1) Cerebral blood flow that shunts to capillaries is increased during antegrade cardiopulmonary bypass under deep hypothermia. (2) During retrograde perfusion, the majority of the blood flow shunts away from brain capillaries, even under normothermic conditions, and blood flow through large venoarterial shunts increases as body temperature decreases. Although the cerebral microcirculation during retrograde perfusion is decreased, retrograde perfusion provides some degree of oxygenation to the body.

Animals↗
PubMed1997

Dynamic cardiac compression improves contractile efficiency of the heart.

The effect of dynamic cardiac compression on left ventricular contractile efficiency was assessed in terms of the pressure-volume relationship and myocardial oxygen consumption. In 11 excised cross-circulated dog hearts, the ventricle was directly compressed during systole (dynamic cardiac compression). Measurements for pressure-volume area (a measure of total mechanical energy), external work, and myocardial oxygen consumption were done before and during dynamic cardiac compression. Dynamic cardiac compression increased pressure-volume area by 28% +/- 17% (mean plus or minus the standard deviation) and external work by 24% +/- 20% (p = 0.0000185 and 0.0000212, respectively) at given end-diastolic and stroke volumes without affecting myocardial oxygen consumption. As a result, the oxygen cost of pressure-volume area, that is, the slope of the myocardial oxygen consumption-pressure-volume area relationship, significantly decreased by 16% +/- 13% (p = 0.0000135) whereas the pressure-volume area-independent myocardial oxygen consumption was unchanged. Then, contractile efficiency, that is, the reciprocal of the slope of the myocardial oxygen consumption-pressure-volume area relationship in joules significantly improved from 45% +/- 8% to 53% +/- 13% (p = 0.0000437). When the native myocardial oxygen consumption-pressure-volume area relationship was assessed by subtracting the dynamic cardiac compression pressure applied to the heart, the slope of the myocardial oxygen comsumption-pressure-volume area relationship returned to the control level. This indicates that the contractile efficiency of the native heart was not affected by dynamic cardiac compression. We conclude that dynamic cardiac compression enhances left ventricular pump function by improving the contractile efficiency of the overall heart leaving the energetics of the native heart unchanged.

Animals↗
PubMed1997

Role of tyrosine specific phosphorylation of cellular proteins, especially EGF receptor and p125FAK in human lung cancer cells.

To clarify the role of tyrosine phosphorylation of cellular proteins in human lung cancer cells, phosphotyrosine (PTYR)-containing proteins in lung cancer cell lines and in paired tissues resected from cancerous and normal lungs were studied by immunoblotting with an anti-PTYR antibody. We found that the profiles of protein phosphorylation were very similar among those cell lines which had different histological features. The major PTYR-containing proteins (180-190 KDa, 120-130 KD, and 95-100 KDa) were detected in lung cancer cell lines. The expression of EGF receptor (EGF-r) (p185) and o-erb B2 protein, and tyrosine phosphorylation of p125FAK were examined in cancerous lung tissues and normal lung tissues. In surgical specimens, approximately half of the samples of lung cancer tissues showed clear elevation of tyrosine phosphorylation. In these cancerous tissues, no clear amplification of EGF-r and c-erb B2 protein expression was observed. However, elevation of tyrosine phosphorylation of p125FAK was observed in cancerous lung tissues but not in normal lung tissues, and its phosphorylation was closely correlated with the nodal involvement of cancer and disease-free survival time. These results suggested that the intracellular signaling pathway via tyrosine phosphorylation plays a role in the generation and immortalization of lung cancer, and assessment of tyrosine phosphorylation of cellular proteins. especially p125FAK, may be available clinically as a prognostic factor.

Adult↗