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Biomedical subjects

A Usui

Publications and source records attributed to A Usui.

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

Ubiquinone redox cycle as a cellular antioxidant defense system.

Ubiquinone (UQ) reductase responsible for reduction of non-mitochondrial UQ was investigated in rats toward demonstrating an antioxidant role of UQ. In the liver, most of cellular UQ-10 reductase activity was attributable to a novel NADPH-UQ reductase in cytosol. The enzyme was not inhibited by dicumarol and rotenone, and had a Km of 19 microM for NADPH and 307 microM for NADH at the optimum pH 7.4. The enzyme was purified 300-fold to apparent homogeneity from the liver cytosol by an affinity chromatographic method. The purified enzyme reduced UQ-10 in lecithin liposomes, and protected the liposomes from lipid peroxidation. Furthermore, supplementation of rats with UQ-10 was observed to increase the enzyme level in their livers without affecting levels of other antioxidant factors. The observations suggested that cytosolic NADPH-UQ reductase is responsible for cellular UQ redox cycle as an endogenous antioxidant.

Animals↗
PubMed1999

Protective effect of nisoldipine on myocardial ischemia during coronary bypass surgery.

BACKGROUND: Nisoldipine, a calcium antagonist, was assessed for myocardial protection and the prevention of reperfusion injury in patients undergoing CABG. METHODS: Of the 34 subjects undergoing CABG in this study, 20 were given nisoldipine orally at 10 mg/day for 2 weeks before surgery (N group) and the other 14 untreated controls (C group). Myocardial protection was conducted via ante-grade cold blood cardioplegia at 20-minute intervals. RESULTS: Myocardial blood flow was significantly higher in the N group (67.8 +/- 21.8 ml/100 g vs. 47.2 +/- 14.4 ml/100 g, p < 0.05) after cardiopulmonary bypass. Serum interleukin-6 levels were significantly lower in the N group 1 hour after reperfusion (116 +/- 58 vs. 409 +/- 362 pg/ml, p < 0.05), as were serum lactate dehydrogenase levels immediately after surgery (888 +/- 268 vs. 1350 +/- 486 IU/L, p < 0.05). The N Group showed a better left ventricle stroke work index 6 hours after surgery (43 +/- 8 vs. 36 +/- 9 g.m/m2). Dopamine dosage in the N group on postoperative day 1 was lower than in controls (5.3 +/- 1.9 vs. 3.0 +/- 2.4 micrograms/kg/min). CONCLUSIONS: Preoperative nisoldipine treatment increased blood flow in the postischemic myocardium and prevented myocardial damage and reperfusion injury to some extent.

Administration, Oral↗
PubMed1999

Protective effects of ONO-5046*Na, a specific neutrophil elastase inhibitor, on postperfusion lung injury.

BACKGROUND: Polymorphonuclear neutrophil elastase might contribute to postperfusion lung injury, so we evaluated the protective effect of ONO-5046*Na, a specific inhibitor of polymorphonuclear neutrophil elastase, against such an injury. METHODS: The study was done using 8 mongrel dogs that received ONO-5046*Na (15 mg/kg per hour) (group O) and 8 control dogs (group C), all of which had 1 hour of partial bypass and 5 hours of observation. RESULTS: The respiratory index showed no significant changes in group O, but increased significant in group C (1.4+/-2.0 versus 5.1+/-4.7, p = 0.0047). Pulmonary extravascular water volume increased markedly in group C but only slightly in group O (group C 20.6+/-8.7, group O 11.2+/- 2.7 mL/kg; p = 0.0005). Blood concentrations of polymorphonuclear neutrophil elastase and interleukin-6 showed more than a tenfold increase in group C (PMN elastase, group C 12.9+/-12.8, group O 2.4+/-1.3 ng/mL; IL-b, group C 11.0+/-9.3, group O 2.9+/-3.8 pg/mL; p < 0.05) but were only slightly higher in group O. Histologic examination revealed interstitial and intraalveolar edema in group C, but group O was virtually normal. CONCLUSIONS: ONO-5046*Na inhibits polymorphonuclear neutrophil elastase and maintains better pulmonary function, so it should reduce postperfusion lung injury.

Animals↗
PubMed1999

Comparative clinical study between retrograde cerebral perfusion and selective cerebral perfusion in surgery for acute type A aortic dissection.

OBJECTIVE: Selection of a brain protection method is a primary concern for aortic arch surgery. We performed a retrospective study to compare the respective advantages and disadvantages of retrograde cerebral perfusion (RCP) and selective cerebral perfusion (SCP) in patients who underwent surgery for acute type A aortic dissection. METHODS: The study reviewed 166 patients who underwent surgery at Nagoya University or its eight branch hospitals between January 1990 and August 1996. There were 91 patients who received SCP and 75 patients who underwent RCP. Results for these two groups were compared. RESULTS: There were no significant differences in age, gender, Marfan syndrome rate, DeBakey classification, or emergency operation rate. Rates of various preoperative complications were similar except for aortic valve regurgitation. Arch replacement was performed more often in SCP than in RCP patients (49% vs. 27%, P = 0.0028). There were no significant differences between groups in cardiac ischemic time or visceral organ ischemic time. However, RCP group showed shorter cardio-pulmonary bypass time (297+/-99 vs. 269+/-112 min, P = 0.013) and lower the lowest core temperature (21.6+/-3.1 degrees C vs. 18.7+/-2.1 degrees C, P = 0.0001). SCP duration was longer than RCP duration (103+/-56 vs. 54+/-24 min, P < 0.0001). Despite these differences, RCP patients were not significantly different from SCP patients with regard to any postoperative complication, neurological dysfunction (16 vs. 19%), or operative mortality (all deaths within the hospitalization; 24 vs. 21%). Regarding neurologic dysfunction, there were six cases of coma, six of motor paralysis, two of paraplegia and one of visual loss among SCP patients, and eight cases of coma, three of motor paralysis, and three of convulsion in the RCP group. The incidence of motor paralysis was higher in the SCP group, while the incidence of coma was higher in the RCP group. CONCLUSIONS: RCP can be performed without clamping or cannulation of the cervical arteries, which is an advantage in reducing the chances of arterial injury or cerebral embolization. RCP is comparable to SCP in terms of clinical outcome.

Acute Disease↗
PubMed1999

Implantation of an endovascular covered stent-graft for distal aortic arch aneurysm via midsternotomy under pigtail catheter guidance.

We implanted an endovascular covered stent-graft for distal aortic arch aneurysm involving the left subclavian artery in 12 cases. A stent-graft was delivered just below the aneurysm via aortotomy with direct vision using a 12 F delivery sheath under guidance of a pigtail catheter placed via the groin artery. The proximal anastomosis of the stent-graft was performed with inclusion technique, and the aortotomy was then closed with it. This technique reduces operative damage by eliminating distal anastomosis and should reduce operative mortality and morbidity.

Adult↗
PubMed1999

Validity of sleep log compared with actigraphic sleep-wake state II.

Twenty-five young people (Y group), three elderly people and seven people with various sleep disorders (SD group) kept a sleep log for 2-7 days, and their wrist-activity was monitored simultaneously. The sensitivity and specificity of the sleep log, and the ratio of agreement between the sleep log and actigraphic sleep-wake state were calculated. The sensitivity and specificity in Y group were 87.93+/-6.49% and 96.51+/-2.37%, respectively. The sensitivity in SD group was significantly lower than in Y group. Even in Y group one-hour agreement ratios dropped during the sleep onset period.

Adult↗
PubMed1999

Heparin coating extends the durability of oxygenators used for cardiopulmonary support.

Acomparative study was performed between a noncoated and heparin-coated cardiopulmonary support (CPS) systems with the same design and structure (Terumo Corporation, Capiox-SX series) to evaluate whether or not heparin coating extends oxygenator service life. Fifty patients underwent CPS from January 1993 until December 1997, and 54 oxygenators (Capiox-SX series) were used. There were 35 noncoated oxygenators (Group NC) and 19 heparin-coated ones (Group HC). Significant predictors for the durability of oxygenators were evaluated by a nonparametric survival analysis and a proportional hazards regression analysis. Thirteen of 35 Capiox-SX and only 2 of 19 Capiox SX-HP revealed gas transfer failure and had to be exchanged. The average life span of the Capiox-SX and Capiox-SX-HP were calculated to be 78.6 +/- 16.8 and 168 +/- 15.4 h, respectively. Group HP showed significantly longer durability than Group NC (p = 0.0017), although there were differences of perfusion index and platelet counts between the 2 groups. Heparin coating of the CPS system remained one of the 2 significant predictors (hazards ratio 8. 871, p = 0.0449) to determine the durability of oxygenators by increasing stepwise multivariate proportional hazards regression analysis, along with anemia with less than 8 g/dl hemoglobin (hazards ratio 9.438, p = 0.0173). Heparin coating of the CPS system assures improved durability because heparin-coated oxygenators have a longer service life than noncoated ones.

Anemia↗
PubMed1999

Effects of proximal ventricular septal pacing on hemodynamics and ventricular activation.

Recently the use of alternate site pacing to improve cardiac function in patients with bradyarrhythmias has increased. In the present study, hemodynamics of right ventricular septal pacing were studied in seven dogs. A bipolar screw-in lead and endocardial lead were placed in the proximal right ventricular septum and right ventricular apex, respectively. The right ventricle was paced from each site. A conductance catheter and Millar catheter were inserted into the left ventricle to determine the left ventricular pressure and the pressure-volume loop. Cardiac output was measured using the thermodilution method. In five of the seven dogs, ventricular activation was documented by isochronal epicardial activation mapping during each pacing mode. Mean arterial pressure and cardiac output during septal pacing were significantly higher than during apical pacing (110 +/- 17 mmHg vs 100 +/- 18 mmHg; 1.00 +/- 0.39 L/min vs 0.89 +/- 0.33 L/min). The positive dp/dt during septal pacing was significantly higher than during apical pacing (2137 +/- 535 mmHg/s vs 1911 +/- 404 mmHg/s). End-systolic elastance during septal pacing was significantly higher compared to apical pacing (13.1 +/- 0.3 mmHg/mL vs 8.9 +/- 4.0 mmHg/mL). The ventricular activation time during septal pacing was significantly shorter than during apical pacing. The epicardial maps generated during septal pacing were similar to those from atrial pacing. We conclude that hemodynamics and interventricular conduction are less disturbed by proximal right ventricular septal pacing than apical pacing in dogs with normal hearts.

Animals↗
PubMed1999

[Usefulness of urethral descent for evaluating the type of female stress urinary incontinence].

BACKGROUND: To select suitable treatment for stress urinary incontinence (SUI), both urethral function and urethral mobility must be assessed. Abdominal leak point pressure (ALPP) is considered to be useful to evaluate urethral function, and radiographic findings are effective to evaluate urethral mobility. However no adequate methods to measure urethral mobility with videourodynamics study (VUDS) exist. We measured the downward movement of the membranous urethra at the same time as ALPP was measured on VUDS, and examined whether or not the urethral descent on VUDS is useful to evaluate urethral mobility. METHODS: The subjects were 28 women with over grade II SUI (according to McGuire's grading) who underwent bead chain cystography and VUDS. As a classical index of urethral mobility, we measured the change of posterior urethrovesical angle (PUVA) and vesical neck descent during Valsalva maneuver on bead chain cystography. The videourodynamic urethral catheter had a radiographic marker that permitted the identification of the location of the urethral pressure sensing aperture. The catheter was fixed at the position where the urethral pressure aperture reached the point of highest pressure. The urethral descent was defined as the downward movement of the urethral marker during Valsalva maneuver while measuring ALPP. According to the urethral descent the patients were classified as follows: 1) hyper-mobile group; urethral descent was over 5 mm. 2) non-mobile group: urethral descent was under 5 mm. The severity of SUI was evaluated with 1 hr. pad weighting test, ALPP and maximum urethral pressure. RESULTS: The urethral descent was significantly related to vesical neck descent and PUVA change. In the non-mobile group (11 cases), ALPP was significantly lower, and urine loss on the pad weighting test was significantly greater than that in the hyper-mobile group (17 cases). The non-mobile group exhibited more severe incontinence than the hyper-mobile group. When the patients were classified according to Blaivas's classification, all patients in type III and 2 in type I were in the non-mobile group. These 2 type I patients had low ALPP (40 cm. water and 70 cm. water) and a history of radical hysterectomy. Therefore these patients were diagnosed with ISD due to the fixed urethra. CONCLUSIONS: Urethral descent is an useful index of urethral mobility. In the non-mobile group, the pathophysiological cause of SUI was not urethral hypermobility but ISD, and it was diagnosed as type III SUI without urethral mobility. We consider that urethral descent assesses urethral mobility more accurately than vesical neck descent, and that urethral descent is a valuable parameter on VUDS.

Adult↗
PubMed1999

Valvulotomy of calcified aortic valves using the neodymium: yttrium-aluminum-garnet (Nd:YAG) laser.

The neodymium: yttrium-aluminum-garnet (Nd:YAG, wavelength; 1064 nm) laser knife was used for valvulotomy of severely calcified aortic valves in 12 patients. The fibrous layer enveloping the calcium deposits was peeled off the valvular annulus and the native valvular leaflet. The underlying calcium deposits were then resected. The average aortic cross-clamp time was 69 +/- 21 minutes. The cardiopulmonary bypass time averaged 118 +/- 32 minutes. All of the patients were discharged from the hospital without complications. Laser valvulotomy can be used to resect severely calcified aortic valves without mechanical crushing, reducing the risk of embolization.

Aged↗
PubMed1998

A heat shock-related protein, p20, plays an inhibitory role in platelet activation.

Some low molecular mass heat shock proteins (HSPs) appear to act as molecular chaperones, but their exact physiological roles have not been fully elucidated. We reported previously that a 20-kDa protein (p20), which is classified as a low molecular mass HSP, is present at high levels in skeletal and smooth muscles. In the present study, we investigated a physiological role of p20 on platelet function in vitro and ex vivo. p20 inhibited platelet aggregation using human platelets dose-dependently induced by botrocetin. On the other hand, HSP27, the other type of low molecular mass HSP, did not affect platelet aggregation. When p20 (300 microg/kg) was injected intravenously as a bolus in hamsters, platelet aggregation ex vivo induced by botrocetin was also significantly inhibited. In order to further investigate the inhibitory effect by p20 on platelet activation, we performed platelet aggregation induced by thrombin or ADP using human platelets. p20 markedly prevented platelet aggregation induced by thrombin, but not ADP. These findings suggest that p20 can act intercellularly to regulate platelet functions. Our results may provide the basis for a novel defensive system to thrombus formation.

Adenosine Diphosphate↗
PubMed1998

[A case of aortic prosthetic valve endocarditis with aortic root aneurysm].

A 72-year-old male who underwent patch closure of atrial septal defect and aortic valve replacement (AVR) 10 years ago was diagnosed as aortic prosthetic valve endocarditis for recurrent fever, coexisting paravalvular leakage and aortic root aneurysm by transthoracic and transesophageal echocardiography. Operative findings showed mechanical prosthesis was dehiscenced in part and limited subannular aneurysm that was healed macroscopically. The hole of the aneurysm was closed by direct suture. Re-AVR, mitral valve replacement and tricuspid annuloplasty for complicating mitral valve stenosis and regurgitation and tricuspid valve regurgitation was performed. The patient is now doing well for one year after the reoperation.

Aged↗
PubMed1998

Vena cava occlusion with balloon to control blood pressure during deployment of transluminally placed endovascular graft.

Transluminally placed endovascular graft (TPEG) replacement has been applied to treat various aortic diseases. At the moment of deployment, TPEG receives a pressure pulse force to shove it distally, which possibly results in misplacement. Moreover, deploying the TPEG in the aorta increases cardiac afterload, which may damage myocardial function. To avoid these risks, we developed a new technique to control blood pressure by almost complete venous return occlusion. Two occlusion balloon catheters are inserted into the superior and inferior vena cava via the femoral vein. TPEG is deployed at the proper position during inflation of the vena cava balloon to maintain a blood pressure as low as 60 mm Hg by cardiac preload blockage. We, thus far, have not experienced even a trivial sequela with this technique.

Aortic Diseases↗
PubMed1998

Inhibitory effect of bacterial attachment on candidal growth due to adherence with mannose-sensitive pili.

A bacterial strain with affinity to Candida albicans was successfully obtained from a natural environment. An uncovered Petri dish containing a suspension of heat-killed C. albicans cells was allowed to stand in a laboratory for several days. Some bacteria which had adhered to the candidal cells were tested for their ability to agglutinate the cells. A bacterial strain, designated later as CAB-1, was found to agglutinate candidal cells through bridging by mannose-sensitive pili. CAB-1 showed similar bacteriological characteristics to those of Citrobacter freundii by ID test. The adherence of CAB-1 to candidal cell was precisely presented by scanning electron microscopy. The inhibitory effect of CAB-1 attachment to candidal cells on the growth of Candida was also preliminarily confirmed.

Agglutination↗
PubMed1998

Validity of sleep log compared with actigraphic sleep-wake state.

Seven women and 11 men, mean age 30.1 years, kept a sleep log for 5-7 days, and their wrist activity was monitored each minute. Sleep-wake state in the sleep log and actigraphic sleep-wake state were compared, and the sensitivity and specificity of the sleep log were calculated for each subject. The ratio of agreement between these two parameters was computed for each subject. The sensitivity and specificity of the sleep log were 72.73-97.56% (mean 86.71%) and 92.85-99.68% (mean 97.04%), respectively. The agreement ratio was 87.30-97.85% (93.48%), but 1-h agreement ratios from midnight dropped during the sleep onset period.

Activity Cycles↗
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↗