Search PubMed⌕ Search

Biomedical subjects

A Usui

Publications and source records attributed to A Usui.

At least 55 records · Page 3Linked to original sources
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

Early experience of retrograde cerebral perfusion.

Since 1990, retrograde cerebral perfusion has been applied in aortic arch surgery in the Nagoya University group to protect the brain. This study reviews the group's early clinical results, and especially of neurological outcome in patients undergoing aortic arch surgery via mid sternotomy by using retrograde cerebral perfusion only via the superior vena cava. Seventy-three cases (47 men, 26 women; mean age 62.3 (range 26-82 years)) participated in the study. True aneurysm was diagnosed in 17 cases and aortic dissection in 56. Emergency operations were performed in 49 cases (67%). The proximal aortic arch was replaced in 38 cases, the total aortic arch in 21, the distal arch in six, and the aortic root in two. Mean (s.d.) retrograde cerebral perfusion duration was 55(23) (range 12-115) min and superior vena cava flow rate 350(143) ml/min. Excluding four cases of early surgical death, a total of 10 patients (14.5%) showed neurological dysfunction. Symptoms were coma in eight cases and motor paralysis in two. Three of these 10 cases were recovered without symptoms and six died. The early mortality rate was 19.2%. Significant differences in retrograde cerebral perfusion duration (49(20) versus 83(18) minutes, P < 0.001), superior vena cava pressure (23.2(7.2) versus 28.2(7.4) mmHg, P = 0.046), and preoperative cardiac arrest P < 0.05) were evident between groups with and without neurological dysfunction. There were no neurological dysfunctions in patients undergoing retrograde cerebral perfusion for < 60 minutes at under 30 mmHg of superior vena cava pressure. In conclusion, retrograde cerebral perfusion may be used to extend the duration of safe cerebral circulatory arrest.

Aortic Dissection↗
PubMed1997

Blood cardioplegia infusion using a recirculation type circuit generates bradykinin in significant amounts during open heart surgery.

The single pass type (SP) of blood cardioplegia is commonly used in North America during open heart surgery. However the recirculation type (RC) of blood cardioplegia is still widely used in other areas including Japan. Infusion blood cardioplegia using the latter technique often decreases the perfusion pressure. To determine the cause for this, blood levels of bradykinin (BK) were measured in cardiopulmonary bypass (CPB) and the 2 types of blood cardioplegic circuits. As the BK levels in the RC cardioplegia (>3,000 pg/ml) rose, the perfusion pressure decreased abruptly with the increase of the BK levels in the CPB circuit. With SP cardioplegia, the BK level was not increased either during cardioplegia (p < 0.009) or CPB (p < 0.009), and the perfusion pressure was not decreased (p < 0.02). We concluded that the SP circuit is superior to the RC one because of the lesser production of BK and thus lesser fluctuation of perfusion pressure.

Aged↗
PubMed1997

A clinical study for the durability of oxygenators on cardiopulmonary support.

Cardiopulmonary support (CPS) requires durability of the oxygenator. The life span of the oxygenator is affected by various clinical factors, including patient condition, perfusion condition, and equipment usage. Predictors for the durability of oxygenators were evaluated clinically in this study. Thirty-two patients, who had undergone CPS during the last 3 years in our institute were assigned to this study. Fifty oxygenators had been used (Capiox SX in 19, CB Maxima in 23, and AL-6000 in 8). Significant predictors for the durability of oxygenators were evaluated by nonparametric survival analysis and proportional hazards regression analysis. Univariate regression analysis revealed 6 significant predictors for the life span of oxygenators. These were the oxygenator type, type of centrifugal pump, acidosis with blood pH less than 7.35, base excess less than -5, blood glutamic-oxaloacetic transaminase (GOT) levels greater than 1,000 IU, and blood lactate dehydrogenase (LDH) levels greater than 3,000 IU. After multivariate analysis, there remained only 2 significant predictors. An oxygenator used with a noncoated CPS system (Capiox SX with Capiox EBS) proved to have a significantly shorter life span than one used with a heparin-coated system (CB Maxima or AL-6000 with CB BP-80) (hazards ratio, 3.588, p = 0.0065). Patient conditions, which revealed acidosis with less than -5 of base excess, significantly shortened the life of the oxygenator (hazards ratio, 3.595, p = 0.0188).

Adult↗
PubMed1997

Clinical study of totally roller pumpless cardiopulmonary bypass system.

We have developed a low negative pressure vacuum suction system in which cardiotomy suction is performed by the negative pressure of the venous reservoir controlled by a vacuum controller. We have employed this vacuum suction system with a centrifugal pump as a totally roller pumpless cardiopulmonary bypass (CPB) system. In this study, the clinical availability and hemocompatibility of our totally roller pumpless CPB system were evaluated by a randomized prospective study. Thirty patients undergoing aortocoronary bypass grafting were assigned to the study. Data from seventeen patients treated with a totally roller pumpless CPB system were compared with data from 13 treated with a conventional roller pump CPB system. Totally roller pumpless CPB reduces hemolysis, showing lower plasma free hemoglobin levels (81.8 +/- 25.0 versus 42.0 +/- 16.3 at 30 min after CPB initiation, p < 0.05), higher plasma haptoglobin levels (37.8 +/- 36.6 versus 77.2 +/- 31.3 at 120 min after CPB, p < 0.05), and lower blood lactate dehydrogenase (LDH) levels (1391 +/- 497 versus 972 +/- 187, p < 0.01) than those of CPB with a roller pump suction with no significant difference between platelet counts. Arterial blood oxygen tension after using a totally roller pumpless CPB system was slightly better than that with a roller pump (396 +/- 48 versus 437 +/- 43, p = 0.069); however, there was no significant difference in intubation times between groups. A totally roller pumpless CPB system provides sufficient biocompatibility for the blood to reduce hemolysis significantly and simplifies and miniaturizes the entire CPB system to achieve good visuality and handling for control as well.

Aged↗
PubMed1997

[Long-term late results of pericardiectomy for constrictive pericarditis].

Twenty-four cases of the constrictive pericarditis were operated on pericardiectomy from 1966 to 1990. One case died because of massive bleeding, LOS, and respiratory failure immediately after the operation. A long-term follow up study was performed up to 27 years (mean 13.1 years) in other cases. Ten cases died during the follow up period (cardiac: 6, non cardiac: 4). Five cases of the cardiac deaths had major complications: tabes dorsalis, chronic respiratory failure, pacemaker implantation, mitral regurgitation, emergency operation at high age (78 years old). The survival rates of 5, 10, and 15 years were 85%, 67%, and 58.2%, respectively (Kaplan-Meier). All of survival cases are now in NYHA I or II class in satisfactory. We concluded that pericardiectomy is a very effective treatment for constrictive pericarditis but a more careful follow up is required especially in cases complicated with other major problems because cardiac function is not so recovered as normal level after surgery due probably to readhesion and fibrotic changes of the myocardium.

Adult↗
PubMed1996

Emergency aortic arch replacement in a patient with idiopathic thrombocytopenic purpura.

We herein report the case of a 56-year-old man with idiopathic thrombocytopenic purpura who required an emergency aortic arch replacement. Intraoperatively, hemostasis was achieved using platelet transfusions. Postoperatively, the use of high-dose gamma-globulin therapy was able to maintain an adequate platelet count and good hemostasis.

Aortic Dissection↗
PubMed1996

Early clinical results of retrograde cerebral perfusion for aortic arch operations in Japan.

BACKGROUND: In Japan, retrograde cerebral perfusion (RCP) has been used for protection of the brain since 1986. The techniques vary by institution, and thus the optimum perfusion conditions have not yet been established. METHODS: A survey of 49 institutions was performed to investigate the early results of RCP in Japan. There were 228 patients collected, 46 (20.2%) of whom sustained brain complications. Twenty-seven patients had permanent and 19, temporary neurologic dysfunction. There were 31 early deaths (13.6%) and an additional 14 hospital deaths (6.1%). Significant predictors of brain complications and mortality were evaluated by univariate analysis and multivariate analysis using stepwise logistic regression. RESULTS: By multivariate analysis, preoperative cardiac arrest (odds ratio 8.901, p = 0.0004) and RCP duration longer than 60 minutes (odds ratio 3.234, p = 0.0352) were significant predictors of permanent neurologic dysfunction. Preoperative hemodynamic compromise (odds ratio 6.150, p = 0.0070), presence of preoperative neurologic symptoms (odds ratio 7.155, p = 0.0283), and left thoracotomy (odds ratio 2.37, p = 0.0335) were significant predictors of early death. Duration of RCP was the single RCP-related factor predictive of a brain complication (odds ratio 1.025 per minute, p < 0.0001). The incidence of permanent neurologic dysfunction was less than 10% when the RCP time was shorter than 60 minutes but increased abruptly when the RCP time exceeded 100 minutes, and it remained approximately 15% between 60 and 99 minutes. CONCLUSIONS: Less than 60 minutes of RCP can be tolerated with minimal risk of brain complication. Retrograde cerebral perfusion is one method of cerebral protection during circulatory arrest. This method is not the complete answer for brain protection, but, given specific guidelines, it may help prolong the safe time of circulatory arrest.

Aorta, Thoracic↗
PubMed1996

Nafamostat mesilate reduces blood-foreign surface reactions similar to biocompatible materials.

BACKGROUND: Nafamostat mesilate (FUT-175) is a synthetic serine protease inhibitor that inactivates coagulation, fibrinolysis, and platelet aggregation. Nafamostat mesilate may suppress the blood-foreign surface reaction similar to biocompatible materials by blocking factor XIIa. METHODS: We performed an in vitro study of cardiopulmonary bypass (CPB) with fresh human blood among the following three groups: standard CPB sets (C), biocompatible CPB sets (B), and standard CPB sets with FUT-175 (10 mg/L) (F). A clinical study using these same CPB groups also was performed in 45 patients undergoing aortocoronary bypass operations (15 patients each). We injected FUT-175 at 40 mg/h during CPB. RESULTS: In the in vitro study, both groups B and F showed significantly lower levels of coagulation factors, thrombin-antithrombin III complex, fibrinopeptide A, beta-thromboglobulin, complement C3a, granulocyte elastase, and free hemoglobin than group C at the conclusion of the study. Thrombin-antithrombin III complex and free hemoglobin in group F also were lower than in group B. The platelet count remained at a higher level in group F than in the other groups. Separation of bradykinin was suppressed most significantly in group F. In the clinical study, group F also showed significantly lower levels of alpha 2-plasmin inhibitor plasmin complex and C3a than both groups C and B. There were minimal levels of free hemoglobin in group F. CONCLUSIONS: Nafamostat mesilate may contribute major beneficial effects toward conservation of blood during CPB and prevention of coagulopathy after CPB.

Benzamidines↗
PubMed1996

Case report: hepatic adenoma with bone marrow metaplasia in a patient with glycogen storage disease type 1a.

A 34 year old man with glycogen storage disease type 1a had two hepatic tumours since 18 years of age. They had continued to grow until he was 24 years old, but showed no further growth since then. He underwent a right hepatic trisegmentectomy with caudate lobectomy under veno-venous bypass. The tumour in the posterior segment showed nodule-within-nodule appearance. Histologically, the inner adenoma with dysplasia, bone marrow metaplasia and lymphocytic infiltration was separated by a fibrous band from the outer adenoma of usual histology.

Adenoma↗
PubMed1996

[Usefulness of bladder auto-augmentation in neurogenic bladder: a case report].

A 41-year-old male with myelomenigocele underwent a bladder auto-augmentation and endoscopic collagen injections. He has been performing self intermittent catheterization for 10 years but urinary incontinence remained unchanged. Furthermore, he suffered from recurrent pyelonephritis due to the left vesicoureteral reflux. A preoperative fluoroscopic urodynamic study showed a poorly compliant bladder with the maximal bladder capacity of 200 ml at 60 cmH2O. The left vesicoureteral reflux was observed at 10 cmH2O. The low compliant bladder was treated with the bladder autoaugmentation and the left vesicoureteral reflux was treated with the endoscopic subureteral injection of collagen 5 months after the previous operation. A fluoroscopic urodynamic study 6 months postoperatively showed the increase of the maximal bladder capacity of 300 ml at 18 cmH2O and the reflux disappeared completely. The endoscopic periurethral injections of collagen improved his persisting urinary incontinence. In patient with neurogenic bladder having a lot of clinical problems, bladder auto-augmentation is less invasive and offers many advantages over enterocystoplasy.

Adult↗
PubMed1996

Collagen injection for intrinsic sphincteric deficiency in men.

PURPOSE: We evaluated the efficacy of collagen injections in the treatment of male urinary incontinence due to intrinsic sphincteric deficiency. MATERIALS AND METHODS: A total of 88 men (mean age 68 years) with mild to severe intrinsic sphincter deficiency underwent a mean of 3.5 transurethral injections of collagen (mean total volume injected 25 ml.). Patients were subdivided into 2 groups based on use of more than 3 or 3 or fewer pads per day. Patient age, pad use before treatment, duration of leakage, number of injections, volume of collagen used and etiology of incontinence were compared for the 2 groups. RESULTS: Of the patients 42 became nearly completely dry, 19 had substantial improvement but still required 1 to 3 pads per day, 14 consistently used fewer pads but still more than 3 per day and 13 showed no improvement. Most injections were performed with the patient under local anesthesia and no significant morbidity occurred. CONCLUSIONS: In select patients collagen injections appear to be effective, easy to deliver and safe. Pretreatment incontinence severity, concomitant detrusor abnormalities and etiology of intrinsic sphincteric deficiency other than radical retropubic prostatectomy were associated with a worse response to collagen therapy.

Aged↗
PubMed1995

Mitral valve replacement via right thoracotomy after coronary arterial grafting.

Mitral valve replacement was performed through a right thoracotomy using femorofemoral bypass under profound systemic hypothermia in a 62-year-old man who had undergone coronary artery bypass grafting using both internal thoracic arteries. The right thoracotomy approach minimizes the risk of injury to the arterial grafts, and deep hypothermia obviates the need to interrupt the grafts to administer cardioplegia. This technique provides excellent exposure of the mitral valve while minimizing the operative risk.

Bioprosthesis↗
PubMed1995

Regional cerebral tissue blood flow measured by the colored microsphere method during retrograde cerebral perfusion.

Brain tissue blood flow was measured precisely by the colored microsphere method during retrograde cerebral perfusion in 10 normothermic mongrel dogs. The average tissue blood flow rates to the cerebral cortex, cerebral medulla, brain stem, cerebellum, and spinal cord during retrograde cerebral perfusion at 25 mm Hg of external jugular venous pressure were 10.5 +/- 10.3, 4.2 +/- 4.6, 11.1 +/- 9.8, 12.3 +/- 8.6, and 9.1 +/- 5.8 ml/min per 100 gm, respectively. The brain was perfused wholly by retrograde cerebral perfusion without lateralization. Total cerebral blood flow was calculated as the sum total rates of blood flow to each area. Total cerebral blood flow during retrograde cerebral perfusion at 25 mm Hg was 7.8 +/- 4.4 ml/min, which represented 3.5% +/- 1.9% of whole body blood flow and one third of the total cerebral blood flow (28.0 +/- 4.2 ml/min) during cardiopulmonary bypass at a flow rate of 1000 ml/min. Oxygen consumption and carbon dioxide elimination by the total cerebrum during retrograde cerebral perfusion at 25 mm Hg were 0.54 +/- 0.23 ml/min and 34 +/- 15 mumol/min, respectively, or 8.6% +/- 3.6% and 7.0% +/- 3.1% of the corresponding whole body value and represented about one third of that measured during cardiopulmonary bypass (1.21 +/- 0.39 ml/min and 96 +/- 15 mumol/min). Total cerebral blood flow, total cerebral oxygen consumption, and carbon dioxide elimination increased as the external jugular venous pressure increased from 15 to 25 mm Hg; however, no further increase occurred once the external jugular venous pressure exceeded 25 mm Hg.

Animals↗
PubMed1995

Conspicuous growth of intravenously inoculated Staphylococcus aureus in subcutaneously established Ehrlich ascites tumor tissue of mice.

Intratumoral growth of Staphylococcus aureus was compared with the intrarenal growth, to examine the usefulness of the method as a marker of its pathogenicity. When 5 x 10(7) CFU/mouse of three derivatives from S. aureus Cowan I with different intrarenal growth were intravenously injected into Ehrlich tumor-bearing mice, they lodged in the tumor tissue at approximately 10(3) CFU/0.1 g by 30 min after infection, and grew in the range of 10(6) CFU/0.1 g to 10(8) CFU/0.1 g by day 4, regardless of their intrarenal growth capacity. In contrast, S. saprophyticus lodged in both tissues to the same degree as S. aureus, but did not grow at all. The time course of the staphylococcal growth was different between tumor tissue and kidney, suggesting differences in the local responses against S. aureus.

Animals↗
PubMed1995

Auxiliary method for clonal identification of Staphylococcus aureus by protein band pattern of released proteins on SDS-polyacrylamide gel.

A supportive method for clonal identification of Staphylococcus aureus strains was devised. Culture supernatant obtained by cellophane surface culture was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) without performing any concentration procedure prior to electrophoresis. The combined use of cellophane surface culture and SDS-PAGE was convenient for determining whether the strains belonged to the same clone or not when conducted in conjunction with other tests for bacteriological characterization.

Bacterial Proteins↗
PubMed1995

Subcutaneous growth of Staphylococcus aureus concomitantly inoculated with Ehrlich ascites tumor cells.

Intratumoral growth of Staphylococcus aureus Cowan I-derived AP332 was examined by subcutaneous inoculation of cocci in doses ranging from 18 to 1.8 x 10(5) CFU with Ehrlich ascites tumor cells. Inoculation of 18 CFU AP332 resulted in staphylococcal growth in one of five mice, and the proportion of mice established intratumoral infection increased with the initial inocula. Six other strains of S. aureus also grew in the tumor tissue, and none of the three strains of coagulase-negative staphylococci grew at all. Ethanol-killed tumor cells did not promote staphylococcal growth as vigorously as the live tumor cells, especially when the initial inoculum of AP332 was smaller than 10(4) CFU.

Abscess↗