Characterization of microbial consortia that reductively dechlorinate 4-chlorophenol and transform phenol to benzoate enriched from estuarine sediment of Lake Shinji.

Monochlorophenols were degraded to benzoate via phenol by the initial dechlorination and the subsequent conversion of phenol to benzoate in anaerobic sediment samples of estuarine Lake Shinji under methanogenic conditions. To characterize bacteria that dechlorinate 4-chlorophenol and transform phenol to benzoate, we analyzed the microbial community structure of the enrichment culture with each 4-chlorophenol and phenol by the limiting dilution method with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) of 16S rRNA gene. After serial dilution of the culture, the 4-chlorophenol-dechlorinating culture consisted of two dominant bacteria, one of which was most homologous with Dehalobacter sp. In the enriched culture with phenol, minor band homologous with Cryptanaerobacter phenolicass corresponded to the transformation activity.

Formation and characterization of planar lipid bilayer membranes from synthetic phytanyl-chained glycolipids.

The formability, current-voltage characteristics and stability of the planar lipid bilayer membranes from the synthetic phytanyl-chained glycolipids, 1, 3-di-O-phytanyl-2-O-(beta-glycosyl)glycerols (Glc(Phyt)(2), Mal(N)(Phyt)(2)) were studied. The single bilayer membranes were successfully formed from the glycolipid bearing a maltotriosyl group (Mal(3)(Phyt)(2)) by the folding method among the synthetic glycolipids examined. The membrane conductance of Mal(3)(Phyt)(2) bilayers in 100 mM KCl solution was significantly lower than that of natural phospholipid, soybean phospholipids (SBPL) bilayers, and comparable to that of 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) bilayers. From the permeation measurements of lipophilic ions through Mal(3)(Phyt)(2) and DPhPC bilayers, it could be presumed that the carbonyl groups in glycerol backbone of the lipid molecule are not necessarily required for the total dipole potential barrier against cations in Mal(3)(Phyt)(2) bilayer. The stability of Mal(3)(Phyt)(2) bilayers against long-term standing and external electric field change was rather high, compared with SBPL bilayers. Furthermore, a preliminary experiment over the functional incorporation of membrane proteins was demonstrated employing the channel proteins derived from octopus retina microvilli vesicles. The channel proteins were functionally incorporated into Mal(3)(Phyt)(2) bilayers in the presence of a negatively charged glycolipid. From these observations, synthetic phytanyl-chained glycolipid bilayers are promising materials for reconstitution and transport studies of membrane proteins.

Muscarinic receptor stimulation by carbachol improves functional recovery in isolated, blood perfused rabbit heart.

OBJECTIVE: The aim was to test whether, besides adenosine A1 receptors, other receptors coupled to the "inhibitory" GTP binding protein Gi confer protection against ischaemic and reperfusion injury. METHODS: Isolated hearts were Langendorff perfused at 37 degrees C with blood and were divided into five groups, all subjected to 45 min zero flow normothermic ischaemia, followed by 1 h reperfusion. Group 1 consisted of control untreated hearts (n = 5). Group 2 consisted of hearts treated with the muscarinic agonist carbachol (CCh, 10 microM; n = 5). In group 3 (CCh+atropine, n = 5) 5 microM atropine was given as well as CCh. Groups 1, 2, and 3 were paced at 3 Hz except during ischaemia. Groups 4 (n = 5) and 5 (n = 6) were similar to groups 1 and 2, except that pacing was continued throughout ischaemia. RESULTS: In group 1, left ventricular end diastolic pressure increased during ischaemia, from 7.2(SEM 1.2) mm Hg to 57(5.6) mm Hg, and remained increased during reperfusion, whereas in group 2, it increased moderately during ischaemia, from 9.2(0.9) mm Hg to 21.6(4.9) mm Hg and returned to preischaemic levels during reperfusion. In hearts paced during ischaemia, contracture developed faster than in unpaced hearts, but CCh still delayed contracture. Postischaemic recovery of isovolumetric left ventricular pressure or its first derivative (dP/dt) and reactive hyperaemia were significantly greater in CCh treated hearts [left ventricular pressure = 69.8(4.9)% of preischaemic value after 60 min reperfusion] than in control hearts [29.3(6.8)%]. Recovery of left ventricular pressure and dP/dt was worsened by pacing, but CCh still improved this recovery [left ventricular pressure = 13.1(8.4)% in control, 46.7(5.3)% in CCh treated hearts]. The CCh effect could be prevented by atropine. ATP breakdown and lactate accumulation during the first minute of ischaemia were lower in non-paced CCh treated hearts than in controls. ATP recovered better at the end of reperfusion in both non-paced [7.1(0.72) mumol.g-1] and paced [4.4(0.77) mumol.g-1] CCh treated hearts, as compared with non-paced [1.8(0.58) mumol.g-1] and paced [1.2(0.39) mumol.g-1] control hearts. In paced hearts, less creatine kinase and lactate dehydrogenase were released in the CCh treated group throughout the reperfusion phase. CONCLUSIONS: Carbachol improves functional recovery and confers cellular protection, and this protection depends mainly but not entirely on its bradycardic effect.

Oxidative damage in selenium deficient hearts on perfusion with adriamycin: protective role of glutathione peroxidase system.

The protective effects of the glutathione peroxidase system against functional damage induced by perfusion of isolated hearts with adriamycin, an anthracycline antibiotic, were studied. We used selenium deficient rats, in which cardiac glutathione peroxidase activity was only 3% of control rats. Both contractile tension and coronary flow decreased during perfusion with the antibiotic. The degree of decline was significantly greater in the selenium deficient hearts than in the control hearts. The increase in malondialdehyde, a product of lipid peroxidation, induced by adriamycin perfusion was more evident in selenium deficient hearts, though the level of reduced glutathione was well maintained. Isolated mitochondrial function also decreased after aerobic adriamycin perfusion and the decrease was greater in selenium deficient rats. These observations indirectly suggest that the decrease in cardiac function induced by adriamycin is protected by the glutathione peroxidase system and that the decrease may be due, at least in part, to damage to the mitochondria caused by oxygen radicals generated by adriamycin.

A new model of cerebral microthrombosis in rats and the neuroprotective effect of a Rho-kinase inhibitor.

BACKGROUND AND PURPOSE: The aim of this study was to develop a new model of stroke based on endothelial damage and thrombotic occlusion in a perforating artery, leading to small cerebral infarcts and neurological deficits in rats. Moreover, the neuroprotective efficacy of fasudil, a rho-kinase inhibitor, was investigated in this model. METHODS: Fifty-six male Sprague-Dawley rats were used in the present study. Rats were anesthetized with sodium pentobarbital, and 100 microg of sodium laurate was injected into the left internal carotid artery on days 1 and 3. The thrombus induction and consequent of ischemic brain damage were examined by histopathological analyses and neurological deficit scoring in a posture reflex test. To investigate the neuroprotective effects of fasudil, 1 or 10 mg/kg was administered intraperitoneally 5 minutes after the first injection of sodium laurate and once daily thereafter on the following 2 days. RESULTS: One hour after the injection of sodium laurate, microscopic examination of phosphotungstic acid hematoxylin-stained sections (n=5) revealed that microthrombi containing fibrin strands obstructed the perforating arteries in the ipsilateral hemisphere. Under a transmission electron microscope (n=6), endothelial cells appeared exfoliated and the vascular lumen was obstructed by a thrombus composed of degranulated platelets, fibrin, leukocytes, and erythrocytes. No evidence of endothelial cell damage or thrombus could be found in the ipsilateral side of the pial artery (middle cerebral artery). Twenty-four hours after the second injection of sodium laurate (day 4), 13 of 15 rats (86.6%) showed mild to severe neurological deficits. Multiple small cerebral infarcts were observed in the hippocampus, cortex, and thalamus. Treatment with fasudil (1 and 10 mg/kg, n=15 each) resulted in a significant improvement in neurological deficits. Fasudil also significantly reduced the area of cerebral infarction. CONCLUSIONS: We present a new model of stroke in rats, in which the perforating arteries are selectively occluded by microthrombi. This model is useful to investigate the pathophysiology and treatment of small cerebral infarction, which is caused by perforating arterial occlusive diseases such as lacunar infarcts. Fasudil may be beneficial in the treatment of acute ischemic stroke.

Antianginal effects of hydroxyfasudil, a Rho-kinase inhibitor, in a canine model of effort angina.

1. The effects of Rho-kinase inhibitor, fasudil, and of a more specific Rho-kinase inhibitor, hydroxyfasudil, on pacing-induced myocardial ischaemia were determined in anaesthetized open-chest dogs. 2. The dogs were subjected to left anterior descending coronary artery (LAD) stenosis producing a sufficient ischaemia as measured by ST-segment depression on electrocardiograms only when the hearts were paced 60 beats min(-1) above the baseline. After a recovery (nonpacing) period, drugs or saline were infused intravenously over 30 min. The animals were again subjected to 5 min of pacing 25 min after the initiation of the treatment. 3. Hydroxyfasudil (0.1 and 0.3 mg kg(-1)) and fasudil (0.3 mg kg(-1)) suppressed the ST-segment depression. Hydroxyfasudil and fasudil also increased the regional blood flow of the LAD perfused endomyocardium region in the canine model of effort angina. 4. To determine the flow profile for hydroxyfasudil in dogs, blood flow in three vascular beds was measured. Hydroxyfasudil (0.3 mg kg(-1) for 30 min) significantly increased coronary blood flow and vertebral blood flow, without significantly changing the femoral blood flow. 5. Hydroxyfasudil had no inotropic or chronotropic effect on the isolated hearts of guinea-pigs. Hydroxyfasudil (2 mg kg(-1) for 20 min) did not affect the PR or QTc interval in anaesthetized dogs. 6. Inhibition of Rho-kinase appears to protect myocardium subjected to pacing-induced ischaemia through the increase in the regional myocardial blood flow. Hydroxyfasudil may be categorized as a novel type of anti-anginal drug, without any inotropic or chronotropic effects.

The myocardial recovery mode after cold storage for transplantation with Collins' solution and cardioplegic solution. A functional and metabolic study in the rat heart.

Mechanisms and kinetics of the effects of the ionic composition of two different storage solutions, an intracellular type and an extracellular type, were analyzed by examining the myocardial functional and metabolic recovery processes during the early reperfusion periods after 3 hours of cold storage using an isolated perfused working rat heart model. The hearts were stored either in our own cardioplegic solution (group 1) or in Collins' solution (group 2) for 3 hours at 4 degrees C and were then reperfused. The electromechanical activity in group 1 was elevated, as indicated by a higher incidence of ventricular fibrillation at 5 minutes of reperfusion (group 1: 5/6; group 2: 0/5; p < 0.05). The coronary flow rate in group 2 was significantly lower, at least for the first 15 minutes after reperfusion, than that of group 1, suggesting the possible existence of vasoconstriction in group 2. Although myocardial oxygen uptake during this period was smaller in group 2, the recovery of myocardial high-energy phosphate levels was better and creatine kinase leakage was less in group 2. The recovery of aortic flow after 30 minutes of reperfusion was significantly better in group 2 (group 1, 59.1 +/- 5.8%; group 2, 71.7 +/- 6.0%; p < 0.01), although the early recovery was somewhat worse in group 2. These data suggest that the heart stored in an intracellular-type solution, compared with one stored in an extracellular-type solution, recovers in an electromechanically suppressed fashion during the early reperfusion phase, associated with a better metabolic recovery and a slower but larger functional recovery. The disadvantage of the intracellular-type solution, however, may be its effect on the increase of coronary vascular resistance during the early reperfusion period.

Collins' solution for cold storage of the heart for transplantation must be reversed with cardioplegic solution before reperfusion. A functional and metabolic study in the rat heart.

The following hypotheses were tested using an isolated perfused working rat heart model: (1) Collins' solution for cold storage of the heart is harmful for the heart during reperfusion; (2) a "reverse" of the intracellular-type Collins' solution with an extracellular-type cardioplegic solution before reperfusion is able to prevent this disadvantage of Collins' solution. The following two major groups (I and II) and five subgroups (-a to -e) in each group were prepared. In group I (reversed group); the hearts were initially stored in Collins' solution but were reversed by a 1-minute flush with cardioplegic solution followed by storage in cardioplegic solution for the last 1 to 180 minutes of the total 3-hour storage, that is, groups I-a (reversed for 1 minute), I-b (10 minutes), I-c (30 minutes), I-d (90 minutes), and I-e (180 minutes). In group II (nonreversed control group); the hearts were stored in Collins' solution throughout 3 hours and were also divided into five subgroups of groups II-a, II-b, II-c, II-d, and II-e in which only a 1-minute flush with Collins' solution was performed at the point corresponding to group I. The coronary flow in any of group II showed a marked decrease during the early reperfusion period. In group I, however, the coronary flow increased significantly in proportion to the duration of the reversing phase. The recovery of the aortic flow and the cardiac output in group I showed a bell-shaped pattern in relation to the duration of the reversing phase, reaching their peak values when reversed for 30 minutes (group I-c). The prolonged reverse (180 minutes) resulted in a deterioration of functional recovery associated with a poorer preservation of high-energy phosphates and a larger enzyme leakage. These results suggest that the beneficial effects of intracellular-type Collins' solution for cold storage of the heart were further improved by reversing Collins' solution with the extracellular-type cardioplegic solution for the last 30 minutes of the 3-hour cold storage because the disadvantageous vasoconstriction due to Collins' solution during reperfusion was successfully prevented by the replacement of intravascular and extravascular Collins' solution with cardioplegic solution before the reperfusion.

Effects of left heart bypass on right ventricular performance. Evaluation of the right ventricular end-systolic and end-diastolic pressure-volume relation in the in situ normal canine heart.

Although left heart bypass has gained popularity as a powerful technique to assist the severely failed left heart, apparent right heart failure has often developed during the bypass procedure. We investigated whether the coexisting right heart failure is attributable to the left heart bypass in 16 open-chest dogs. We evaluated the effects of left heart bypass on the right ventricular systolic properties by the slope of the end-systolic pressure-volume relation and its effects on the diastolic properties by chamber compliance. Overall right ventricular performance was assessed by the end-diastolic pressure versus cardiac output relationship. The left heart bypass decreased the slope slightly when the assisted flow ratio exceeded 75% (-14% +/- 8% at the assisted flow ratio of 100%, p less than 0.02) and thus had a deleterious influence on right ventricular performance. The left heart bypass, on the other hand, had a counteracting beneficial influence on right ventricular performance through the increase in chamber compliance (38% +/- 5%, p less than 0.01) and the decrease in pulmonary arterial input resistance (-15% +/- 12%, p less than 0.01). The net effect of the left heart bypass was the increase in cardiac output (20% +/- 2%, p less than 0.05) for any given right ventricular end-diastolic pressure. We conclude that in normal hearts the left heart bypass augments right ventricular performance. We ascribe these beneficial effects to diastolic ventricular interdependence and afterload unloading.

A new method of retrograde cardioplegic administration. Right ventricular protection by right atrial perfusion cooling.

Retrograde administration of cardioplegic solution via the right atrium with continuous cooling of the right ventricular cavity (right atrial perfusion cooling) was assessed for its protective effect in 12 dogs with occlusion of the right coronary artery subjected to global ischemia for 60 minutes. After an initial administration of 4 degrees C crystalloid cardioplegic solution by antegrade aortic perfusion, myocardial protection was established either by right atrial perfusion cooling (group I; n = 6) or by antegrade aortic perfusion alone (group II; n = 6). The right ventricular temperature was approximately 15 degrees C in group I and 20 degrees C in group II. After ischemia for 60 minutes, the adenosine triphosphate content of the right ventricular free wall was significantly higher in group I than in group II (24.4 +/- 1.45 versus 13.8 +/- 2.34 mumol/gm dry weight, p less than 0.05). The percent recovery of right ventricular contractility, which was evaluated by end-systolic pressure-volume relationships, was significantly better in group I at each reperfusion period (30 minutes: 130.0% +/- 9.6% versus 86.1% +/- 11.8%, p less than 0.05; 60 minutes: 159.6% +/- 12.9% versus 96.5% +/- 20.1%, p less than 0.05). Postischemic right ventricular stiffness (reciprocal value of compliance) increased in group II compared with group I, although the difference was not statistically significant. There were no major differences in percent recovery of the left ventricular end-systolic pressure-volume relationships between the two groups. The evidence suggests that the right atrial perfusion cooling method produces excellent right ventricular protection.

Simplified Manouguian's aortic annular enlargement for aortic valve replacement.

A simplified Manouguian's aortic annular enlargement for aortic valve replacement with prosthetic valve was performed in a patient with severe aortic stenosis and mild regurgitation by preserving both the anterior mitral leaflet and the left atrial roof intact. This method minimized the operative risk by avoiding injury to the mitral valve, while inserting a possibly two-size-larger prosthetic valve. The inserted prosthetic valve was positioned parallel to the original aortic valve. Moreover, the incision from the top of the commissure between the noncoronary cusp and left coronary cusp through the interventricular fibrous trigone appears to be easily extended into the exact center of the anterior mitral leaflet if further enlargement is required.

Left ventricular-coronary sinus shunt through a septal aneurysm after mitral valve re-replacement.

We describe a case in which a left ventricular-coronary sinus communication through a dissecting ventricular septal aneurysm developed after a redo mitral valve replacement. The outlet orifice of the communication was located in the side wall of the ostium of the coronary sinus. Both the communication and the aneurysm were successfully dealt with by performing a right atriotomy and by opening the aneurysm from its outlet orifice.

Postoperative cardiac rhythms with superior-septal approach and lateral approach to the mitral valve.

BACKGROUND: The superior-septal approach provides an excellent view of the mitral valve and therefore has received considerable interest. However, the safety of this approach is controversial because it requires division of the sinus node artery in most cases. METHODS: Postoperative cardiac rhythms were analyzed in 152 consecutive patients who underwent mitral valve procedures between January 1992 and February 1995 with a conventional right lateral left atriotomy (group 1, n = 69) or the superior-septal approach (group 2, n = 83). Follow-up ranged from 2 to 38 months, and the mean follow-up was 16.1 months in group 1 and 13.8 months in group 2. RESULTS: The mortality rate was similar in the two groups (1.4% in group 1 and 1.2% in group 2), and the causes of death were not related to the left atriotomy. At discharge, 96% of the patients in group 1 who were in sinus rhythm preoperatively and 78% of those in group 2 remained in sinus rhythm. At the last follow-up, 88% of these patients in group 1 and 83% in group 2 remained in sinus rhythm. Among the patients in atrial fibrillation or junctional rhythm before operation, 12% in group 1 and 11% in group 2 had regained sinus rhythm at the last follow-up. There were no significant differences in these values. CONCLUSIONS: Although the incidence of dysrhythmias was higher with the superior-septal approach in the early postoperative period, this approach provides an excellent operative view of the mitral valve and similar results in terms of late postoperative cardiac rhythms as the right lateral left atriotomy.

Comparative study of cell saver and ultrafiltration nontransfusion in cardiac surgery.

Hemoconcentration for the establishment of no-donor blood transfusion in open heart surgery was assessed in regard to both the saving of protein and platelets and the exclusion of free hemoglobin. Two different types of hemoconcentrator were compared: the ultrafilter (group I, 6 patients) and the Cell Saver (group II, 6 patients). The total serum protein level, expressed as the percent recovery of the preoperative value, after hemoconcentration was significantly higher in group I (group I versus group II: total serum protein, 118% versus 87% [p less than 0.05]; fibrinogen, 77% versus 50% [p less than 0.01]; immunoglobulin, 83% versus 60% [p less than 0.01]). The platelets also seemed to be well preserved after hemoconcentration in group I. Although the exclusion of free hemoglobin from plasma was inferior in group I compared with group II, the postoperative plasma free hemoglobin level did not increase in group I. We conclude that use of the Cell Saver in nontransfusion cardiopulmonary bypass might cause a severe depletion of various proteins and that the ultrafilter is both safer and more useful if employed routinely.

Thrombolytic efficacy of a modified tissue-type plasminogen activator, SUN9216, in the rat middle cerebral artery thrombosis model.

We have developed a model whereby the middle cerebral artery in an experimental animal can be occluded by a photochemical reaction between rose bengal and green light. This causes endothelial injury followed by platelet adhesion, aggregation and formation of a platelet-rich thrombus at the site of the photochemical reaction. SUN9216, a modified tissue-type plasminogen activator, is a new thrombolytic agent which consists of the fibrin kringle 1 domain of plasminogen and the two kringles, the serine protease domains of the native tissue-type plasminogen activator. The mannose glycosylation site on the kringle 1 of tissue-type plasminogen activator is modified to yield a compound with a longer half-life in the blood than native tissue-type plasminogen activator. We evaluated the thrombolytic effects of recombinant tissue-type plasminogen activator and SUN9216 in the thrombotically occluded rat middle cerebral artery. SUN9216 was administered by continuous infusion or as a single bolus injection 30 min after the middle cerebral artery had been occluded by a thrombus. Both SUN9216 and recombinant tissue-type plasminogen activator caused reopening of the middle cerebral artery by thrombolysis. The efficacy of SUN9216 was higher than that of recombinant tissue-type plasminogen activator. Further, the area of ischaemic cerebral damage caused by the middle cerebral artery occlusion was significantly (P < 0.05) reduced by SUN9216, but in this respect, recombinant tissue-type plasminogen activator was ineffective.

Effect of dietary docosahexaenoic acid in the rat middle cerebral artery thrombosis model.

We investigated the effect of dietary docosahexaenoic acid (DHA) supplementation on the thrombolytic efficacy of recombinant tissue-type plasminogen activator (rt-PA), platelet aggregability, serum cholesterol and phospholipids. Male Wistar rats (6 weeks old) received dietary DHA supplementation (300 mg/kg per day) for 8 weeks. The rat middle cerebral artery (MCA) was occluded by a thrombus induced by photochemical reaction between rose bengal and green light which cause endothelial damage followed by platelet adhesion, aggregation and formation of a platelet and fibrin-rich thrombus at the site of photochemical reaction. The MCA blood flow was monitored using a laser Doppler flowmeter. rt-PA was administered 30 min after the middle cerebral artery had been occluded by a thrombus. This regimen produced a significant (P < 0.05) decrease in serum free-cholesterol and phospholipids levels, inhibited platelet aggregation ex-vivo induced by collagen in whole blood (P < 0.05), reduced thromboxane (TX) B2 formation (P < 0.01) in whole blood and prolonged the time for thrombotic MCA occlusion (P < 0.01) as compared with values obtained from animals on standard diet. Further, dietary DHA enhanced thrombolytic efficacy of rt-PA and reduced the size of ischaemic cerebral lesions. Our findings suggest that dietary DHA produces antithrombotic effects via metabolic conversion to non-atherogenic and non-platelet stimulant metabolites.

Thromboxane A2 synthetase inhibitor failed to ameliorate the arterial narrowing during the chronic phase of cerebral vasospasm.

To determine the pathogenetic mechanism underlying the maintenance of arterial narrowing during the chronic phase of cerebral vasospasm caused by subarachnoid hemorrhage (SAH), we examined the effect of ozagrel, a thromboxane A2 (TXA2) synthetase inhibitor, on chronic vasospasm in a canine two-hemorrhage model in comparison with that of fasudil, an inhibitor of protein kinases. The magnitude of the vasospasm was determined angiographically. On SAH day 7, a vasospasm was observed in every dog. Intraarterial or intravenous administration of ozagrel (3 mg/kg/30 min) did not reverse the vasospasm but tended to increase bleeding. In contrast, intraarterial administration of fasudil (3 mg/kg/30 min) significantly reversed the vasospasm. These findings suggest that: 1) TXA2 does not participate in the maintenance of chronic vasospasm after SAH; and 2) the protein kinases, particularly myosin-light chain kinase and protein kinase C, are involved in the pathogenesis of arterial narrowing during the chronic phase of cerebral vasospasm.

Observation of everyday hand-washing behavior of Japanese, and effects of antibacterial soap.

People wash their hands only for a short time outside the home and when preparing meals at home. This may not be sufficient for those who prepare meals because of possible secondary contamination from food. Although washing with a placebo soap for a short period (lathering 3 s and rinsing 8 s) cleansed from hands about 95% of the total coliforms transferred from ground meat, an antibacterial soap further reduced the coliform count significantly (p < 0.01). To effectively avoid secondary contamination, it is recommended that people should more frequently wash their hands, using an antibacterial soap on the areas that have been in contact with raw meat, poultry, seafood, eggs, vegetables and other foods.

Risk stratification analysis of operative mortality in heart and thoracic aorta surgery: comparison between Parsonnet and EuroSCORE additive model.

OBJECTIVE: Our purpose was to compare the performance of risk stratification model between Parsonnet and European System for Cardiac Operative Risk Evaluation (EuroSCORE) in our patient database. METHODS: From August 1994 to December 2000, 803 consecutive patients have undergone heart and thoracic aorta surgery using cardiopulmonary bypass and scored according to Parsonnet and EuroSCORE algorithm. The population was divided into five clinically relevant risk categories. We compared correlation of predicted mortality and observed mortality between these two models. Score validity was assessed by calculating the area under the receiver operating characteristic (ROC) curve. RESULTS: Overall hospital mortality was 4.5%. In Parsonnet model, predicted mortality was 2.4% for 0-4% risk, 6.7% for 5-9% risk, 12% for 10-14% risk, 17% for 15-19% risk, 25% for 20% plus risk, and 10.4% for overall patients. Observed mortality was 2.4, 0.4, 5.9, 8.7, 11, and 4.5%, respectively. The thoracic aorta and valve cohort indicated poor correlation between predicted and observed mortality compared to coronary cohort. In the EuroSCORE model, predicted mortality was 1.4% for 0-2% risk, 4.0% for 3-5% risk, 6.7% for 6-8% risk, 9.7% for 9-11% risk, 13% for 12% plus risk, and 5.3% for overall patients. Actual mortality was 0, 1.5, 6.8, 11, 21, and 4.5%, respectively. Each of the thoracic aorta, valve, and coronary cohort indicated good correlation between predicted and observed mortality. Areas under the ROC curves were 0.72 in Parsonnet and 0.82 in EuroSCORE. CONCLUSIONS: The EuroSCORE additive model yielded good predictive value for hospital mortality of Japanese patients undergoing not only cardiac but also thoracic aortic surgery.

Biodegradation of alkyltrimethylammonium salts in activated sludge.

Trimethylamine, dimethylamine and methylamine (actually existing as a salt form in the culture medium) were identified as the intermediates of alkyltrimethylammonium salts in activated sludge obtained from a municipal sewage treatment plant. It was considered that the quaternary ammonium salts with long alkyl chains were degraded to tertiary amine by N-dealkylation at the first stage of the biodegradation pathway. The tertiary amine formed in this pathway rapidly disappeared. In the activated sludge, biodegradabilities based on biochemical oxygen consumption and dissolved organic matter were 7.2-53.7% and 97.4-100%, respectively. These results and the disappearance of intermediates as described above indicate that long chain alkyltrimethylammonium salts are ultimately biodegradable.