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Biomedical subjects

Y Misawa

Publications and source records attributed to Y Misawa.

At least 73 records · Page 4Linked to original sources
PubMed1998

Effect of replacing a high linoleate oil with a low linoleate, high alpha-linolenate oil, as compared with supplementing EPA or DHA, on reducing lipid mediator production in rat polymorphonuclear leukocytes.

The fatty acid composition of rat polymorphonuclear leukocytes (PMN) was modified by diets supplemented with a high linoleate (LA) safflower oil (76% LA), mixtures of eicosapentaenoate (EPA) and safflower oil (EPA(20) containing 20% EPA and 61% LA, EPA(40) containing 40% EPA and 46% LA), mixtures of docosahexaenoate (DHA) and safflower oil (DHA(20) containing 20% DHA and 61% LA, DHA(40) containing 40% DHA and 46% LA) or a high alpha-linolenate (alpha-LNA) perilla oil (57% alpha-LNA and 13% LA), and then lipid mediator production in casein-induced peritoneal PMN were compared. EPA and DHA were relatively ineffective in reducing platelet-activating factor (PAF) production; a statistically significant reduction was observed only in the DHA(40) group. In contrast, perilla oil reduced PAF production by 50% as compared with safflower oil. Arachidonate (AA) in the PAF precursor, 1-alkyl-2-acyl-glycerophosphocholine, was roughly correlated with PAF production, but EPA and DHA in the precursor lipid were relatively unrelated. On the other hand, both PGE2 and LTB4 production correlated positively with AA and negatively with EPA and DHA in PMN phospholipids; EPA tended to be somewhat more effective than DHA in reducing PGE2 and LTB4 formation; the activity of perilla oil was no less than EPA(20). Thus, replacing safflower oil with perilla oil was no less effective than supplementing safflower oil with EPA or DHA (at 40% of total fatty acids) in reducing lipid mediator production in rat PMN.

Animals↗
PubMed1998

Effect of dietary docosahexaenoic acid on in vitro thermogenesis and fatty acid compositions of brown adipose tissue.

Brown adipose tissue (BAT) is a major organ of nonshivering thermogenesis during cold acclimation, overfeeding, and nonthermal restraint stress. An increased unsaturation of fatty acids of membrane phospholipid in BAT has been shown to be closely associated with an enhanced function of this tissue as reported in other tissues. In the previous study, we found that among fatty acids detected, the n-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) in BAT phospholipid is the only fatty acid that altered concomitantly with a change in the in vitro thermogenic capacity for nonshivering thermogenesis of BAT from cold acclimated and restrained rats. To examine the effect of dietary DHA on fatty acid composition of phospholipid and in vitro BAT thermogenic activity, rats were fed a standard diet supplemented with purified DHA for 4 or 16 weeks. Dietary DHA for 4 or 16 weeks increased DHA level in BAT phospholipid, and it also decreased arachidonic acid. The unsaturation index increased and remained unchanged under DHA feeding for 4 and 16 weeks, respectively. In vitro thermogenic activity of BAT remained unchanged and decreased under dietary DHA for 4 and 16 weeks, respectively. These findings indicate that dietary DHA could increase DHA level in phospholipid of BAT, but it could not improve in vitro BAT thermogenic response.

Acclimatization↗
PubMed1998

Evaluation of platelet damage in two different centrifugal pumps based on measurements of alpha-granule packing proteins.

Mechanical trauma caused by centrifugal pumps is usually evaluated in terms of hemolysis. However, platelet damage caused by centrifugal pumps has not been studied well. We evaluated platelet damage in 2 different centrifugal pumps, the Medtronic BioMedicus BP-80 and the Terumo Capiox, in vitro and compared the results in terms of hemolysis. To evaluate platelet damage, the rate of increase (RI) for beta-thromboglobulin (beta-TG) and platelet factor-4 (PF-4) were measured by enzyme immunoassay. RI was defined as follows: RI for beta-TG is deltabeta-TG/deltaN and RI for PF-4 is deltaPF-4/deltaN where deltabeta-TG is the increase in beta-TG, deltaPF-4 is the increase in PF-4, and deltaN is the increase of the passing number, which is defined in the following equation: N = Qt/V (t, time; V, priming volume; Q, flow rate). Each pump was tested in a mock circuit for 3 h under a flow rate of 5 L/min and a pressure head of 100 mm Hg using fresh human heparinized blood (n = 5). For comparison, the normalized index of hemolysis (NIH) values were calculated for both pumps. The NIH values did not indicate a significant difference between the Capiox and the BP-80 pumps (Capiox vs. BP-80, 0.0021 +/- 0.0004 vs. 0.0034 +/- 0.0007, NS). However, the RI values for beta-TG and PF-4 in the Capiox were significantly lower than in the BP-80 (beta-TG, 0.198 +/- 0.047 vs. 0.376 +/- 0.049; PF-4, 0.080 +/- 0.014 vs. 0.268 +/- 0.043, p < 0.05). In conclusion, although there was no significant difference between the 2 pumps in terms of hemolysis, the Capiox centrifugal pump induced less platelet damage than the BP-80. The results suggest that measurements of RI for beta-TG and PF-4 are more sensitive parameters than NIH values for evaluating blood cell damage.

Blood Platelets↗
PubMed1997

Platelet damage caused by the centrifugal pump: in vitro evaluation by measuring the release of alpha-granule packing proteins.

Platelets are more vulnerable to damage than erythrocytes because platelets are easily activated by contact with extracorporeal circuits and by exposure to shear forces. However, the degree of platelet damage caused by centrifugal pumps is unclear. To evaluate platelet damage in different pumping conditions, the rates of increase for specific proteins in platelet alpha-granules, beta-thromboglobulin (beta-TG), and platelet factor 4 (PF-4) were measured in both in vitro simulated left ventricular assist device (LVAD) and cardiopulmonary bypass (CPB) conditions and compared with the erythrocyte trauma. A flow of 5.0 L/min with deltaP of 100 mm Hg for LVAD (low pressure head condition) and a flow of 5.0 L/min with deltaP of 350 mm Hg for CPB (high pressure head condition) were investigated. Each condition was tested 4 times for 3 h in a mock circuit with a Capiox (Terumo, Tokyo, Japan) centrifugal pump using fresh human blood. Blood was sampled at 1 h intervals, measuring plasma free hemoglobin (fHb), beta-TG, and PF-4. To evaluate the degree of damage, the rates of increase of fHb, beta-TG, and PF-4 were calculated for each condition as deltafHb/deltaN, deltabeta-TG/deltaN, and deltaPF-4/deltaN where deltafHb is the increase in plasma free hemoglobin, deltabeta-TG is the increase in beta-TG, deltaPF-4 is the increase in PF-4, and deltaN is the increase in the passing number. The passing number is defined in the following equation: N = Qt/V where t is the time, V is the priming volume, and Q is the flow rate. There was no significant difference between the 2 conditions (low pressure head condition versus high pressure head condition) in the rate of increase of fHb (0.0035+/-0.0004 vs. 0.0034+/-0.0010 g/100 L, NS). Contrary to this, the rates of increase for specific proteins in platelet alpha-granules in the high pressure head condition demonstrated a significantly higher rate of increase than in the low pressure head condition. The mean rate of increase for beta-TG in the low pressure head condition was 0.22+/-0.03 ng/ml and in the high pressure head condition was 0.51+/-0.05 ng/ml (p < 0.05). The rate of increase for PF-4 in the low pressure head condition was 0.11+/-0.02 ng/ml and in the high pressure head condition was 0.30+/-0.06 ng/ml (p < 0.05). These results suggest that measurements of beta-TG and PF-4 may be more sensitive parameters than hemolysis for evaluating blood cell trauma and that platelets are more vulnerable to mechanical damage by a centrifugal pump than erythrocytes.

Blood Platelets↗
PubMed1997

Pannus resection through the tilting disc prosthesis: successful treatment preserving the prosthesis.

A 59-year-old woman was admitted to our hospital because of heart failure. In 1988, she underwent aortic valve replacement with an Omnicarbon valve and mitral valve replacement with a bioprosthetic valve. She was doing well until July in 1996 when she developed heart failure. Echocardiography revealed massive mitral valve regurgitation, and cinefluoroscopy showed implanted Omnicarbon valve dysfunction with a leaflet opening angle of 35 degrees. At reoperation, it was revealed that pannus formation prevented the valve from functioning well. The pannus was resected through the major orifice, and the leaflet was rotated toward the right anterolateral orientation. The worn bioprosthetic valve was replaced with a mechanical one. Postoperative cinefluoroscopy of the rotated Ominicarbon valve showed the opening angle to be 61 degrees.

Aortic Valve↗
PubMed1997

Unilateral pulmonary edema in a patient with ischemic heart failure.

A 72-year-old woman with a history of anterolateral myocardial infarction was in severe respiratory distress with frothy sputum production. Electrocardiogram and echocardiogram detected evidence of ischemic change due to anterolateral myocardial injury. Chest roentogenogram showed unilateral, right side pulmonary edema with a clear left lung field. Mechanical ventilation and diuretic administration contributed to her recovery from heart failure and pulmonary edema. Computed tomographic scan showed no abnormality of the bilateral lung fields or pulmonary vasculature; however, pulmonary perfusion scan and pulmonary angiography revealed reduced blood perfusion in the entire left lung field. Although we have no histological evidence, some pulmonary parenchymal change on the left side might have been the cause of unilateral pulmonary edema in this case. In conclusion, a woman with ischemic heart failure developed unilateral pulmonary edema on the right side, showing reduced blood perfusion on the left side.

Aged↗
PubMed1997

[Rapid ventricular pacing in dogs--the natural history and pathology].

Six dogs were rapidly paced for 4 weeks with a VVI pacemaker, and observed for 4 to 6 weeks after cessation of rapid pacing. Echocardiographic study revealed congestive heart failure at the end of rapid pacing associated with enlarged left ventricles and reduced left ventricular ejection fraction. Four weeks after cessation of rapid pacing, the left ventricular cavity and ejection fraction improved, but did not return to the normal pre-paced values. Six weeks after the cessation, cardiac function recovered, and pathological study of the resected hearts demonstrated normal myocardium without fibrotic or ischemic changes.

Animals↗
PubMed1997

[Repair of ischemic cardiac rupture and perioperative management with mechanical circulatory assist].

Fifteen cases with ischemic cardiac rupture were reviewed. Three cases with subacute free wall rupture of the left ventricle, ten with ventricular septal perforation, and one with both ventricular septal perforation and blow-out type free wall rupture were included in this study. Six patients required mechanical circulatory assist such as IABP (Intra-Aortic Balloon Pumping) and/or V-A bypass before operation. Four patients underwent an emergent operation after establishment of the circulatory assist and two patients had an urgent operation 5 and 10 days after the establishment respectively. Another patient underwent repair of cardiac rupture following manual cardiopulmonary resuscitation. Thus, preoperative mechanical circulatory assist was initiated in seven patients. Eight patients who were not supported by any preoperative mechanical circulatory assist underwent an emergent operation. At operation, infarcted free wall myocardium was resected and repaired with or without a patch, and ventricular septal perforation was repaired with a heterogeneous patch. The seven patients with preoperative mechanical circulatory assist and a patient without it required postoperative mechanical circulatory assist because of intractable heart failure. Six patients with perioperative circulatory assist, however, could not get recovery from their impaired cardiac function, and one died from infective mediastinitis after being weaned from IABP and V-A bypass with PCPS (Percutaneous CardioPulmonary Support). Seven patients who did not have perioperative mechanical circulatory assist uneventfully recovered but one. We concluded that mechanical circulatory assist can give a chance of survival to a patient with far advanced heart failure following ischemic cardiac rupture, and that a prompt and definite diagnosis and a prompt surgical repair are inevitable to get better clinical results.

Aged↗
PubMed1997

[Postoperative inflammatory responses to gelatin- and collagen-impregnated Dacron grafts and changes of endotoxin].

Between June, 1993 and January, 1995 a gelatin-sealed knitted Dacron (Gelseal) (g-G0, n = 7) and a collagen-sealed knitted Dacron graft (Hemashield) (g-H0, n = 8) were randomly implanted to 15 patients (pts) for replacement of thoracic aorta. We evaluated postoperative inflammatory responses and levels of Toxicolor and Endospecy which are the measurements of endotoxin. Five pts in g-G0 and 3 pts in g-H0 showed that a body temperature (BT) were above 37.5 degrees C on the 7th postoperative day (POD). In three of them (2 in g-G0 and 1 in g-H0), BT above 37.5 degrees C continued until POD 14 due to the bacterial infection. The other causes of elevation of BT were pleural effusion (2), pericardial effusion (1) and unknown origin (2). Patients without evidence of infection (n = 12) were divided into 2 groups (g-G: pts with Gelseal, n = 5, g-H: pts with Hemashield, n = 7). On POD3, postoperative BT in g-H was significantly higher than in g-G. And, on POD7, BT in g-G rose up more than in g-H. However, on POD14, BT decreased to the normal range in both groups. The values of WBC in g-G were slightly higher than in g-H and they became normal after POD7 in both groups. The levels of CRP in g-H were higher than in g-G after POD3 and in both groups they were still high on POD14. In terms of endotoxin., Toxicolor was already above the normal range from POD1 and decreased to the normal range after POD14. However, the level of Endospecy kept within normal range. In conclusion, Toxicolor-reactive substance elevates by using Gelseal and Hemashield. Its substance is not endotoxin. It would not be appropriate to consider that endotoxin is an origin of fever between POD7 and 14.

Aortic Aneurysm, Thoracic↗
PubMed1997

Pathologic findings of latissimus dorsi muscle graft in dynamic cardiomyoplasty: clinical implications.

BACKGROUND: We hypothesize that the integrity of the latissimus dorsi muscle graft used to wrap the heart may affect the clinical outcome of patients undergoing dynamic cardiomyoplasty. METHODS: By correlating the pathologic findings with their clinical course in five patients who died 1 month to 6 years after dynamic cardiomyoplasty operation, we sought to discern findings that might shed light on the pathophysiology of cardiomyoplasty. RESULTS: Of the two patients who had a limited clinical response, one had an atrophic, edematous latissimus dorsi muscle with fatty infiltration resulting from cardiac cachexia, and the other had insufficient length of latissimus dorsi muscle to cover a large heart. The remaining patients responded well clinically without signs of pump failure and died at various intervals, mostly of arrhythmias. Autopsy findings included the following: (1) one patient with ischemic cardiomyopathy as the underlying disease had development of rich vascularity in the interface between the muscle wrap and the epicardium; whereas in four others with idiopathic cardiomyopathy, such evidence of collateralization was far less evident. (2) There was a variation in the skeletal muscle transformation achieved, with the fraction type I fatigue-resistant fiber in the muscle wrap ranging from 60% to 100%, in spite of the identical transformation protocol used. Such variation is believed to be genetically based. (3) In one patient, the skeletal muscle was paced to contract at 30 to 50 times/minute (2:1 ratio) for more than 5 years. Nevertheless, the pathologic specimen of the muscle wrap showed only minimal interstitial fibrosis. (4) Relatively thin muscle wrap around the heart found at autopsy could be atrophy but most likely was related to muscle transformation, which is known to reduce muscle mass and increase capillary density. (5) All skeletal muscle grafts showed geometric conformation to the shape of the epicardium and grossly looked as if they were an additional layer of the ventricular wall. Such conformation may facilitate the modulation of the ventricular remodelling process in the failing heart, as has been described both in clinical and experimental studies. CONCLUSIONS: Our findings are consistent with and support a number of mechanisms proposed for cardiomyoplasty. Thus preservation of latissimus dorsi muscle graft integrity may be important in the success of dynamic cardiomyoplasty.

Adult↗
PubMed1996

CD43 expression in a B cell lymphoma, WEHI 231, reduces susceptibility to G1 arrest and extends survival in culture upon serum depletion.

CD43 is a major surface sialoprotein on hemopoietic cells, whose extracellular domain is heavily O-glycosylated. The functional role of CD43 in the hemopoietic system is not fully understood; however, it has been suggested that CD43 may have a role in cell-cell repulsion and in modifying T cell proliferation and activation. CD43 is expressed in immature B cells in the bone marrow, but not by peripheral B cells, except for B-1 B cells and plasma cells. To analyze the biological effect of CD43 in B-lineage cells, we transfected mouse CD43 cDNA into a CD43- B cell lymphoma, WEHI 231, and the growth and survival in culture were compared to those of a parental cell line, human CD8 transfectants, and CD43- revertants established from CD43+ clones. We observed that CD43 expression supported cell growth in culture upon serum reduction, whereas growth of CD43- cell lines was barely detected under this condition. CD43- cell lines accumulated in G1 phase of the cell cycle, and the numbers of viable cells were greatly reduced during culture upon serum depletion, whereas expression of CD43 reduced the susceptibility to G1 arrest and temporarily retarded the apoptotic process, which, in turn, resulted in an increase and maintenance of the number of viable cells in culture. The results suggest that CD43 may have some role in the survival and expansion of B-lineage cells. The biological effect of CD43 was initiated without stimulation by cross-linking and was significantly impaired by replacement of the extracellular domain by the human CD8 extracellular domain. The basis of these regulatory processes is discussed.

Animals↗
PubMed1996

Successful coronary artery bypass grafting for a patient with myelodysplastic syndrome: report of a case.

We report herein the case of a 61-year-old man with myelodysplastic syndrome causing pancytopenia who underwent successful coronary artery bypass grafting (CABG). Preoperatively, his hemoglobin (Hb) value was 10.4 g/dl while receiving transfusions of 1 or 2 units of red blood cells (RBC) every 2 weeks, his white blood cell (WBC) count was 8200/microliter with injections of 100 micrograms granulocyte colony-stimulating factor (G-SCF) every 5 days, and his platelet count was 4.5 x 10(4)/ microliter without platelet transfusion. From the time the pancytopenia was diagnosed in his peripheral blood, he had received a total of 104 units of RBC and 472 units of platelets, following which he developed an antiplatelet antibody, not for a platelet-specific antigen, but for an HLA antigen. Thus, HLA-matched platelets were prepared to prevent bleeding caused by thrombocytopenia, and the WBC count was elevated preoperatively by G-CSF injections. Thereafter, CABG was performed on three vessels. The HLA-matched platelets were transfused as the patient was weaned from the extracorporeal circulation. As a result of these preparations, we were able to protect the patient against bleeding and infection.

Antibodies↗
PubMed1996

[Retrograde aortic dissection during cardiopulmonary bypass a case report successfully treated by contralateral femoral cannulation].

Retrograde aortic dissection is the most critical complication associated with femoral perfusion. It may be related to the trauma of femoral cannulation per se or to the jet of retrograde perfusion. We report the successful repair of a retrograde aortic dissection by composite graft replacement of the dissected ascending aorta using contralateral femoral cannulation. A 66-year-old man presented with aortic regurgitation due to annuloaortic ectasia. At the operation, the right common femoral artery was cannulated, and cardiopulmonary bypass was initiated. Within a few minutes after beginning the bypass, we recognized a retrograde dissection showing a tense bluish bulge in the ascending aorta. Bleeding was detected from the dissected aortic root beside the right coronary ostium. The bypass was interrupted, and contralateral femoral cannulation was performed immediately to re-establish the bypass. Composite graft replacement of the aortic root and ascending aorta was successfully performed under hypothermic circulatory arrest using additional retrograde cerebral perfusion. Pathological findings of the aortic wall revealed cystic medionecrosis. When a retrograde aortic dissection occurs, it is essential to establish antegrade flow. If it is impossible to cannulate at the ascending aorta for any reason, a contralateral femoral cannulation can be used successfully to re-establish the cardiopulmonary bypass because of the easy access.

Aged↗
PubMed1995

Optimizing "delay period" for burst stimulation in dynamic cardiomyoplasty.

Hemodynamic evidence of systolic assist after dynamic cardiomyoplasty remains inconsistent. One of the relevant factors may be how the burst stimulator is programmed. In 3 patients who underwent cardiomyoplasty for idiopathic dilated cardiomyopathy, we examined the modes used to determine the delay period between the R-wave sensing and the onset of burst stimulation during cardiac systole. These modes include the fixed time mode, the valve-synchronized mode, and the flow-optimized mode. The rationale for choosing these modes and the benefits conferred by each are discussed.

Aged↗
PubMed1994

Interleukin 6 gene transcripts are expressed in human atherosclerotic lesions.

Factors controlling the proliferation of vascular smooth muscle cells (SMC) are thought to be key elements in the progression of atherosclerosis. We have previously shown that interleukin 6 (IL-6) stimulates the growth of SMC in vitro and that IL-6 gene transcripts are expressed in atherosclerotic lesions of genetically hyperlipidemic rabbits. To understand the involvement of IL-6 in the development of human atherosclerosis, we investigated IL-6 mRNA expression in atherosclerotic arteries from patients undergoing surgical vascularization, utilizing reverse transcription polymerase chain reaction (RT-PCR) and in situ hybridization analyses. In RT-PCR analysis, the atherosclerotic arteries showed 10- to 40-fold levels of IL-6 mRNA expression over the non-atherosclerotic artery. In in situ hybridization analysis, IL-6 gene transcripts were observed in the thickened intimal layer of atherosclerotic lesions. These results strongly suggest the involvement of IL-6 in the development of human atherosclerosis.

Actins↗