Comparing oxygen transfer performance between three membrane oxygenators: effect of temperature changes during cardiopulmonary bypass

Recently, a new oxygenator (Dideco 903 [D903], Dideco, Mirandola, Italy) has been introduced to the perfusion community, and we set about testing its oxygen transfer performance and then comparing it to two other models. This evaluation was based on the comparison between oxygen transfer slope, gas phase arterial oxygen gradients, degree of blood shunting, maximum oxygen transfer, and diffusing capacity calculated for each membrane. Sixty patients were randomized into three groups of oxygenators (Dideco 703 [D703], Dideco; D903; and Quadrox, Jostra Medizintechnik AG, Hirrlingen, Germany) including 40/20 M/F of 68.6 +/- 11.3 years old, with a body weight of 71.5 +/- 12.1 kg, a body surface area (BSA) of 1.84 +/- 0.3 m(2), and a theoretical blood flow rate (index 2.4 times BSA) of 4.4 +/- 0.7 L/min. The maximum oxygen transfer (VO(2)) values were 313 mL O(2)/min (D703), 579 mL O(2)/min (D903), and 400 mL O(2)/min (Quadrox), with the D903 being the most superior (P < 0.05). Oxygen (O(2)) gradients were 320 mm Hg (D703), 235 mm Hg (D903), and 247 mm Hg (Quadrox), meaning D903 and Quadrox are more efficient versus the D703 (P < 0.05). Shunt fraction (Qs/Qt) and diffusing capacity (DmO(2)) were comparable (P = ns). Diffusing capacity values indexed to BSA (DmO(2)/m(2)) were 0.15 mL O(2)/min/mm Hg/m(2) (D703), 0.2 mL O(2)/min/mm Hg/m(2) (D903), and 0.18 mL O(2)/min/mm Hg/m(2) (Quadrox) with D903 outperforming D703 (P < 0.0005). During hypothermia (32.0 +/- 0.3 degrees C), there was a lower absolute and relative VO(2 )for all three oxygenators (P = ns). The O(2) gradients, DmO(2) and DmO(2)/m(2), were significantly lower for all oxygenators (P < 0.01). Also, Qs/Qt significantly rose for all oxygenators (P < 0.01). The oxygen transfer curve is characteristic to each oxygenator type and represents a tool to quantify oxygenator performance. Using this parameter, we demonstrated significant differences among commercially available oxygenators. However, all three oxygenators are considered to meet the oxygen needs of the patients.     

Nafamostat mesilate reduces blood cell adhesion to cardiopulmonary bypass circuits: an in-vitro study

Nafamostat mesilate (FUT-175) is a protease inhibitor, working as an inactivator of coagulation, fibrinolysis and platelet aggregation. Although FUT-175 directly blocks contact factors in coagulation, it also may decrease activation of humoral cascade systems when used in cardiopulmonary bypass circuits. We performed an in vitro study using fresh human blood in the following cardiopulmonary bypass circuits: standard circuit (C), biosurfaced circuit (B) and standard circuit containing FUT-175 (F). Each circuit was primed with 500 ml of electrolyte solution and 500 ml of fresh blood. Cardiopulmonary bypass was performed using a roller pump for four hours in two sets of each circuit configuration. Platelet factors (platelet count and beta-thromboglobulin), coagulation factors (thrombin-antithrombin III complex and fibrinopeptide A), fibrinolysis factors (alpha 2-plasmin inhibitor complex and alpha 2-plasmin inhibitor), complement factors (C3a, C4a), free hemoglobin, and granulocyte elastase were measured at the beginning and end of the study. Hemocytograms were measured concurrently. The FUT-175 group showed significantly lower levels of the measured indices than the biosurfaced group in thrombin-antithrombin III complex (7.4 +/- 2.1 vs. 54.9 +/- 38.1 ng/ml), fibrinopeptide A (7.2 +/- 2.0 vs. 20.2 +/- 14.6 ng/ml), beta-thromboglobulin (1940 +/- 250 vs. 2438 +/- 314 ng/ml) and free hemoglobin (25.2 +/- 14.3 vs. 73.8 +/- 18.4 mg/dl). There were no significant differences between Group F and Group B in platelet count, C3a, C4a and granulocyte elastase, although these indices were significantly lower in Groups F and B when compared to Group C.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evidence of a threshold value of glycated hemoglobin to improve the course of renal function in type 2 diabetes with typical diabetic glomerulopathy.

We recently observed that the course of glomerular filtration rate (GFR) rapidly declines in a subgroup of Type 2 diabetic patients (D) with abnormalities of albumin excretion rate (AER) and typical diabetic nephropathy, despite tight blood pressure control. The aim of this study was to evaluate whether amelioration of blood glucose control, using insulin, improves the course of GFR. GFR decay was measured by spline modeling analysis of the plasma clearance rate of 51CR-EDTA, assessed every 6 months. We identified two groups of D using morphometric analysis of renal biopsy, who had values of glomerular basement membrane (GBM) and fractional mesangial volume (Vv mes/glom) respectively below (Group A: 38) or above (Group B: 50) the mean+2SD of values found in 27 kidney donors (GBM: 389 nm; Vv mes/glom: 0.25), as previously described in detail. Median AER was similar at base line in the 2 groups (109 microg/min, 29-1950, in Group A, 113 microg/min, 37-1845, in Group B; n.s.). Conventional metabolic therapy (sulphonylureas and/or biguanides) was used both in Group A and B during a 3 year follow-up period (Period 1). Group B was further divided in two subgroups with body mass index below (Group B, a) and above (Group B, b) the value of 30 kg/m2. Mean +/- SD HbA1c was 8.2 +/- 1.6% in Group A, 8.3 +/- 1.7% in Group B (a) (n.s.) and 9.1 +/- 1.7% in Group B (b) (n.s.). Tight blood pressure control was achieved and maintained using angiotensin converting enzyme inhibitors and/or beta blockers and/or calcium antagonists and/or thiazides. The mean arterial blood pressure (MAP) was 92 +/- 3 mmHg in Group A and 91 +/- 4 mmHg in Group B (n.s.). GFR decay was significantly greater in Group B than in Group A (Group A vs B: +1.21 +/- 0.71 vs -5.86 +/- 1.61 ml/min/1.73 m2/year). Median AER significantly rose in Group B (177 microg/min, p<0.05 vs base line) but not in Group A (134 microg/min, n.s.) during the third year of follow-up. Groups A and B were then followed over 4.1 years (range 3.1-4.4) (Period 2) maintaining the above described antihypertensive regimen, resulting in MAP values similar to those described during Period 1. Group A patients were treated with the same conventional glycemic control during Period 2. Group B (a) was conversely treated with intensive insulin therapy to achieve a HbA1c value below 7.5% (3 daily injections of regular and 1 or 2 daily injections of intermediate acting insulin associated with metformin 500 mg twice daily in 64% of the patients). Group B (b) patients were only treated by metformin (850 mg thrice daily) to achieve a HbA1c value below 7.5%. HbA1c decreased below the 7.5% target value in Group B (a) (7.0 +/- 1.6%, p<0.01 vs Period 1), but not in Group B (b) (8.0 +/- 1.6%, p<0.05 vs Period 1) and in Group A (8.3 +/- 1.7%, n.s. vs Period 1). The GFR decay of Group B, a during Period 2 was lower than that during Period 1 (Period 1 vs Period 2: -5.9 +/- 1.8 vs -1.8 +/- 0.7 ml/min/1.73 m2/year, p<0.01). GFR decay during Period 2 was similar to that observed during Period 1 in Group A (Period 1 vs Period 2: +1.21 +/- 0.71 vs +0.7 +/- 0.6 ml/min/1.73 ml/year, n.s.) and in Group B (b) (Period 1 vs Period 2: -4.4 +/- 0.71 vs -4.2 +/- 0.6 ml/min/1.73 m2/year, n.s.). Median AER did not significantly change in the fourth year of Period 2 , either in Group A or B (Group A vs B: 141 vs 152 microg/min, n.s.). In conclusion, our findings seem to suggest that amelioration of blood glucose control is attained both by insulin and metformin intensive treatment, but only insulin decreases and maintains HbA1c levels below 7.5%. These pattens of HbA1c appear to be a threshold value in order to significantly blunt GFR decay in a subgroup of Type 2 diabetic patients with typical diabetic glomerular lesions, who are less responsive to tight blood pressure control alone. Conversely, the cohort of patients with less severe diabetic glomerulopathy steadily show constant GFR patterns, despite similar abnormalities of albumin excretion rate, and HbA1c average values above 7.5%.     

Sevoflurane improves the neuroendocrine stress response during laparoscopic pelvic surgery

PURPOSE: Stress response to surgery is modulated by several factors, including magnitude of the injury, type of procedure (e.g., laparoscopy vs laparotomy) and type of anesthesia. Our purpose was to compare intra- and postoperative hormonal changes during isoflurane vs sevoflurane anesthesia, in a clinical model of well defined operative stress (laparoscopic pelvic surgery). METHOD: In this prospective randomized clinical study, 20 women requiring laparoscopic pelvic surgery for benign ovarian cysts received either a standard isoflurane plus fentanyl (Group A) or sevoflurane plus fentanyl anesthesia (Group B). Blood samples were collected preoperatively, 30 min after the beginning of surgery, at the end of surgery after extubation, and two and four hours after the end of surgery. Intra- and postoperative plasma levels of norepinephrine, epinephrine, adrenocorticotropic hormone (ACTH), cortisol, growth hormone (GH) and prolactin (PRL) were measured. RESULTS: Catecholamine levels and postoperative pain were similar in both groups. Nonetheless, in comparison to Group A, Group B showed a significant decrease of ACTH, cortisol and GH levels (A vs B at the end of surgery: ACTH 160 +/- 45 vs 100 +/- 40 pg.mL(-1); cortisol 45 +/- 8 vs 23 +/- 7 microg.dL(-1); GH 3 +/- 2 vs 0.8 +/- 0.4 ng.mL(-1); P < 0.001 for all), but enhanced PRL levels (A vs B, at 30 min after the beginning of surgery: 139 +/- 54 vs 185 +/- 22 ng.mL(-1); at the end of surgery: 100 +/- 27 vs 141 +/- 45 ng.mL(-1); P < 0.001 for both). CONCLUSIONS: In the clinical setting of low stress laparoscopic surgery, the type of volatile anesthetic significantly affected the stress response; the changes associated with sevoflurane suggested a more favourable metabolic and immune response compared to isoflurane.     

Effects of escharotomy as abdominal decompression on cardiopulmonary function and visceral perfusion in abdominal compartment syndrome with burn patients

BACKGROUND: Abdominal compartment syndrome (ACS) can become fatal; however, it has rarely been described as a complication of burn injury. This study clarified the physiologic results of abdominal decompression (AD) for ACS in patients with burn injury in detail. METHODS: Extensively burned patients admitted to our burn unit between January 2003 and February 2004 were prospectively monitored by pulmonary artery catheter. Physiologic parameters from the catheter, blood gas analysis, intrabladder pressure as a parameter of intra-abdominal pressure (IAP), peak inspiratory pressure, and urine output (UO) were compared before and after escharotomy as AD in patients with ACS. RESULTS: Eight of 36 patients who had sustained more than 30% total body surface area burn developed ACS requiring AD in 18.3 +/- 4.9 hours. AD significantly decreased IAP (52 +/- 9 cm H2O vs. 26 +/- 7 cm H2O), peak inspiratory pressure (53 +/- 13 cm H2O vs. 35 +/- 6 cm H2O), heart rate, and Paco2, and increased cardiac index (1.6 +/- 0.7 L/min/m2 vs. 2.5 +/- 0.9 L/min/m2), abdominal perfusion pressure (50 +/- 11 mm Hg vs. 72 +/- 17 mm Hg), UO (0.45 +/- 0.46 mL/h/kg vs. 2.0 +/- 2.1 mL/h/kg), and oxygen delivery index (290 +/- 195 mL/m2/min vs. 455 +/- 218 mL/m2/min). Impaired oxygen consumption index increased (86 +/- 43 mL/m2/min vs. 153 +/- 58 mL/m2/min) after AD. CONCLUSION: In patients with severe burn injury, elevated IAP makes pulmonary artery wedge pressure and UO unreliable indices of preload or intravascular volume, and decreases abdominal perfusion in the resuscitation period. AD in these patients significantly improves the ventilation, hemodynamic parameters, and oxygen metabolism.     

Effect of desmopressin acetate on hemorrhage without identifiable cause in coronary bypass patients.

After early hopeful reports, the ability of desmopressin acetate (DDAVP) to substantially reduce post surgical hemorrhage has been questioned. A total of 74 elective coronary bypass patients (Group A) receiving DDAVP (0.3 micrograms/kg) who, in the opinion of the operating surgeon, did not achieve adequate hemostasis after protamine neutralization of heparin were studied. They were compared with 91 age- and sex-matched controls (Group B). Before surgery there was no difference in hematocrit (40.8% vs. 40.3%); bleeding time (5.3 vs. 4.9 sec); platelet count (267 +/- 8 vs. 309 +/- 13 X 10(3)/mm3); fibrinogen (363 vs. 361 mg/dl); or activated clotting time (ACT) (168 +/- 4 vs. 163 +/- 3 sec). Both groups had the same number of grafts (3.3/pt), use of the mammary artery (72%), and average bypass time (124 min). There were also no differences in postbypass ACT (142 +/- 3 vs. 135 +/- 2 sec); platelet count (97 +/- 10 vs. 120 +/- 24 X 10(3)/mm3); and fibrinogen (157 +/- 35 vs. 207 +/- 40 mg/dl). However, postoperative hemorrhage was strikingly different: 1306 +/- 89 vs. 896 +/- 33 ml (P less than .0001). Fifteen patients in Group A bled more than 1.5 liters compared with 4 in Group B. Red cell transfusion rates were 1.23 +/- 0.26 for Group A and 0.35 +/- 0.8 for Group B (P less than 0.005). Sixteen Group A patients received additional blood products (plasma and platelets). The hemorrhage difference remained significant even when these patients were excluded (1098 +/- 57 vs. 896 +/- 34, P less than 0.003). Three Group A patients were re-explored without a bleeding source located.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of bloodless pump prime on cerebral oxygenation in paediatric patients

BACKGROUND: In paediatric patients, crystalloid prime for cardiopulmonary bypass (CPB) causes further haemodilution in comparison with blood-containing prime. Thus it may affect the cerebral oxygen supply/demand balance. The purpose of the study was to compare the effect of bloodless pump prime with that of blood-containing prime on cerebral oxygenation in children. METHODS: Thirty-six paediatric patients scheduled for elective repair of atrial or ventricular septal defect were enrolled. In Group C (n = 18), the CPB circuit was primed only with crystalloid. In Group B (n = 18), red blood cells were added to achieve a haematocrit (Hct) of 20% during CPB. The regional cerebral oxygen saturation (rSO(2)) value measured by near-infrared spectroscopy was compared between the two groups. RESULTS: In both groups, rSO(2) decreased below baseline at the start of CPB and during rewarming (P < 0.001, for both groups during each period). At the start of CPB, haemodilution was greater in Group C than in Group B (Hct 16.1 +/- 0.7% vs. 20.7 +/- 0.5%; P < 0.01), and there was a greater reduction in rSO(2) in Group C (49.0 +/- 5.4% vs. 59.2 +/- 7.0%; P < 0.01). During rewarming, rSO(2) was significantly lower in Group C than in Group B (57.8 +/- 5.3% vs. 62.8 +/- 6.2%; P < 0.01). CONCLUSIONS: In paediatric patients, the haemodilution associated with crystalloid priming causes a greater reduction in rSO(2) than with blood-containing prime at the starting period of CPB and the rewarming period.     

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.     

General anaesthesia combined with bilateral paravertebral blockade (T5-6) vs. general anaesthesia for laparoscopic cholecystectomy: a prospective, randomized clinical trial

BACKGROUND AND OBJECTIVE: The efficiency of bilateral paravertebral blockade combined with general anaesthesia (active) vs. general anaesthesia alone (control) in reducing postoperative pain following laparoscopic cholecystectomy was evaluated using a prospective randomized study design. METHODS: Patients were randomly assigned to either group. Nerve-stimulator guided paravertebral blockade at the T5-6 level was performed with a local anaesthetic mixture (0.30 mL kg(-1)). Twenty millilitres of the mixture contained lidocaine 2% 6 mL; lidocaine 2% 6 mL with epinephrine 1/200 000; bupivacaine 0.5% 5 mL; fentanyl 1 mL (50 microg mL(-1)) and clonidine 2 mL (150 microg mL(-1)). Postoperative pain and consumption of opioids were assessed during the first 72 h. RESULTS: Two-times 30 patients were analysed. Patient characteristics data, and pre- and peroperative variables were similar in both groups. Mean pain scores visual analogue scale were significantly less with active compared with control (P < 0.05) at 6h (1.56 +/- 1.58 vs. 4.78 +/- 1.67), at 12 h (1.52 +/- 1.58 vs. 3.81 +/- 1.63), at 24 h (1.16 +/- 1.34 vs. 2.71 +/- 1.50), at 36h (0.68 +/- 1.02 vs. 2.29 +/- 1.41), at 48h (0.60 +/- 1.04 vs. 1.61 +/- 1.33) and at 72 h (0.40 +/- 0.86 vs. 1.19 +/- 1.16). The number of patients consuming supplemental analgesics was significantly less (P < 0.05) with active compared with control, at 6 h (6 vs. 29), at 12 h (2 vs. 26), at 24 h (1 vs. 23) and at 36 h (2 vs. 15). More patients were free from nausea (P < 0.05) with active compared with control at 6 h (23 vs. 9) and at 12 h (29 vs. 19). CONCLUSION: When used as a complement to general anaesthesia, bilateral nerve-stimulator guided paravertebral blockade with lidocaine, bupivacaine, fentanyl and clonidine may improve postoperative pain relief.     

Pharmacokinetics and pharmacodynamics of ropivacaine 2 mg/mL, 5 mg/mL, or 7.5 mg/mL after ilioinguinal blockade for inguinal hernia repair in adults

The aim of our study was to evaluate the pharmacokinetics and pharmacodynamics of ropivacaine in ilioinguinal-iliohypogastric blocks (IIB). After ethics committee approval and informed consent, 80 male adults scheduled for inguinal hernia repair were enrolled and randomized into four groups. After induction of general anesthesia, an IIB was performed double blinded in Groups 1, 2, and 3 with 0.25 mL/kg ropivacaine 2 mg/mL, 5 mg/mL, or 7.5 mg/mL and with saline in the Control group. Plasma concentration of ropivacaine was determined in venous blood using reversed-phase high-performance liquid chromatography. IIB with ropivacaine resulted in peak plasma concentrations of 0.3+/-0.15 microg/mL (Group 1) (mean +/- SD), 0.75+/-0.45 microg/mL (Group 2), or 1.57+/-0.82 microg/mL (Group 3). These concentrations occurred after 30 (15-60) min, median (range), 30 (10-60) min, and 45 (15-60) min, in the respective groups. Three of 19 patients in Group 1, 6 of 18 in Group 2, and 5 of 20 in Group 3 did not need any additional analgesics within 24 h postoperatively, but all 20 control patients did. Time to the first demand for analgesia was significantly shorter in the Control group (median 0.3 h [range 0-2.8]) compared with 1.5 h (0.5-24 h), 2 h (0.5-24 h), and 2 h (1.0-24 h) in Groups 1, 2, and 3, respectively. Three patients in Group 3 had a postoperative motor block of the femoral nerve. In conclusion, a ropivacaine dose of 0.25 mL/kg of 5 mg/mL seems adequate for IIB accompanying general anesthesia for postoperative pain relief. However, the pharmacokinetic results obtained suggest that even larger doses (0.25 mL/kg of 7.5 mg/mL ropivacaine) for IIB do not result in plasma concentrations in a toxic range. IMPLICATIONS: Ropivacaine, a new local anesthetic, proved to be effective for pain relief after hernia repair in ilioinguinal blocks accompanying general anesthesia. Plasma concentrations peaked after 30-45 min, and were within safe limits after application of 0.25 mL/kg of 2, 5, or 7.5 mg/mL ropivacaine.     

Cardiopulmonary bypass does not alter canine enflurane requirements.

This study determined the effect of cardiopulmonary bypass (CPB) on canine enflurane minimum alveolar concentration (MAC). Fourteen dogs were anesthetized with enflurane in N2O and O2, and after tracheal intubation, the N2O was discontinued. Femoral arterial and pulmonary arterial catheters were placed, and MAC was determined with the tail-clamp method. CPB was initiated via the femoral artery-vein route, with additional venous return obtained from an external jugular vein. Partial CPB was used in the first 10 dogs. In 4 dogs, a membrane oxygenator (group 1) was used, and in the next 6 dogs a bubble oxygenator (group 2) was used. In 4 additional dogs (group 3), using bubble oxygenators, total CPB was achieved by occlusion of the pulmonary artery via a left thoracotomy. The CPB circuit was primed with Ringer's lactate, and circuit blood flows were 70-125 ml.kg-1.min-1, with mean arterial pressures maintained at 50-110 mmHg. MAC was determined again after termination of CPB. In 10 dogs, MAC was also measured during CPB. In 5 dogs MAC was measured after administration of protamine. MAC in all 14 dogs did not change (2.2 +/- 0.3 vs. 2.3 +/- 0.3). MAC remained constant in group 1 (2.4 +/- 0.3 vs. 2.3 +/- 0.4), group 2 (2.2 +/- 0.2 vs. 2.3 +/- 0.3), and group 3 (2.2 +/- 0.1 vs. 2.3 +/- 0.1). Similarly, MAC was unchanged during CPB (2.2 +/- 0.2 vs. 2.2 +/- 0.2) and after protamine (2.3 +/- 0.2 vs. 2.2 +/- 0.3). Temperature was 38.3 +/- 1.2 prebypass and 37.9 +/- 0.9 postbypass.(ABSTRACT TRUNCATED AT 250 WORDS)     

碱性成纤维细胞生长因子转染对半月板纤维软骨细胞增殖、细胞周期及胶原合成影响的研究

目的探索携带碱性成纤维细胞生长因子(bas ic fibrob last grow th factor,bFGF)基因的重组慢病毒载体转染半月板纤维软骨细胞的效能,观察半月板纤维软骨细胞对bFGF基因转染的反应。方法将从1只3月龄新西兰大白兔分离培养的第1代半月板纤维软骨细胞分为实验组(A组)、对照组(B组)和空白组(C组),3组细胞分别以2×104个/孔接种于24孔培养板。细胞生长至60%融合时,A组与克隆有bFGF基因的重组慢病毒载体悬液共培养,B组与不携带任何基因的慢病毒悬液共培养,C组未接受外加处理。共培养48 h后检测3组的细胞周期、胶原合成能力、培养液中bFGF的表达及不同时间各组细胞的细胞增殖能力的变化。结果共培养48 h后在A组测出bFGF浓度为870±60 pg/m l,而B、C组培养液中未能检测出bFGF的表达;共培养6 d后,M TT法检测,A组吸光度(A)值0.427±0.037与B组0.320±0.042和C组0.308±0.034比较差异有统计学意义(P<0.01)。A组细胞周期较B、C组缩短,A组细胞G1期,S期和G2/M期的时间分别为16.28、12.60和11.04 h;而B、C组分别为23.61、16.90和21.33 h及21.56、19.80和21.41 h;A组与B、C组比较差异有统计学意义(P<0.05)。A组细胞每分衰变数(7 281.69±805.50)高于B组(5 916.40±698.11)和C组(5 883.57±922.63),比较差异有统计学意义(P<0.05)。结论借助慢病毒载体能有效实现bFGF基因在半月板纤维软骨细胞的转染;bFGF基因转染能促进半月板纤维软骨细胞的增殖和胶原合成能力。     

Increased in-vitro incubation time of endothelial cells on fibronectin-treated ePTFE increases cell retention in blood flow

Endothelial cell (EC) seeding is postulated as a mechanism of improving patency of small calibre vascular grafts. However, the majority of seeded cells are lost within hours following restoration of blood flow. We postulated that incubating EC in-vitro on a graft will improve adherence and resistance to the sheer stresses of pulsatile blood flow. Fibronectin-treated ePTFE (5 cm x 4 mm ID) seeded with Indium-111-labelled autologous canine EC (1.5 x 10(5) cells/cm2) were incubated for four different time periods; 90 min, 24 h, 72 h and 6 days. Incubated grafts were subjected to blood flow of 75 ml/min for 6 h, in a canine ex-vivo arteriovenous shunt circuit. EC retention during perfusion was studied by measuring gamma activity emitted by the grafts. Cell morphology of non-perfused control groups and perfused groups was compared using scanning electron microscopy (SEM). SEM of control grafts showed progressive EC spreading on the ePTFE surface for up to 72 h incubation. Gamma activity was significantly higher at 6 h perfusion in grafts incubated for 72 h (82 +/- 4%) and 24 h (63 +/- 6%) vs. 90 min (34 +/- 13%, p less than 0.05), and between grafts incubated for 72 h vs. 6 days (55 +/- 7%, p less than 0.05). Perfused grafts incubated for 72 h showed unaltered EC morphology on SEM, few cells remained on 90 min incubated grafts. We conclude that incubating EC on fibronectin-treated ePTFE for 72 h in-vitro after seeding improves cell retention during blood flow.     

IL-6 and IL-8 levels after cardiopulmonary bypass are not affected by surface coating

BACKGROUND.:Contact of blood with the surfaces of the cardiopulmonary bypass (CPB) circuit has been implicated as a cause of the inflammatory response. We undertook a prospective randomized trial of 200 pediatric patients, all with a calculated total bypass flow of less than 2.3 L/min (< 0.96 L/m2/min). METHODS: Patients were randomly assigned to 1 of 4 CPB groups: (1) Nonheparin-bonded circuit with no albumin preprime; (2) Nonheparin-bonded circuit with albumin preprime; (3) Heparin-bonded circuit with no albumin preprime; (4) Heparin-bonded circuit with albumin preprime. Measurements of cytokines, (interleukin [IL]-6, IL-8) and blood cell counts were made prebypass and 6 and 24 hours after institution of cardiopulmonary bypass. RESULTS: Analysis of variance showed no significant difference in any of the clinical or biochemical characteristics of the 4 groups. The interaction between heparin-bonded oxygenators and albumin preprime was not significant. No important differences in IL-6 or IL-8 concentrations were noted after CPB using either heparin or nonheparin-bonded oxygenators with albumin or albumin free preprime using two-way analysis of variance. CONCLUSIONS: Albumin preprime and heparin-bonding do not attenuate the inflammatory response component attributable to the concentration of these markers.     

Increased transcapillary escape rate of albumin in nondiabetic men in response to hyperinsulinemia

Diabetic patients manifest increased vascular permeability. To determine whether insulin per se might increase vascular permeability, five nondiabetic men were studied by the hyperinsulinemic-euglycemic clamp technique. Each subject received a 0.72-nmol/kg body wt i.v. insulin bolus, followed by a 72-pmol.kg-1.min-1 insulin infusion for 4 h. Euglycemia was maintained by the Biostator glucose controller. At 7 h of study, 10 microCi i.v. 125I-labeled albumin was injected as bolus dose. Frequent blood samples were drawn during the next 70 min for determination of the transcapillary escape rate (TER) of albumin. Subjects returned 1-2 wk later for a control study, during which 0.45% saline was infused at a rate identical to the dextrose and insulin infusion rates during the hyperinsulinemic clamp. The mean +/- SE serum insulin levels during the hyperinsulinemic clamp and saline infusion were 9786 +/- 126 and 46 +/- 4 pM, respectively, whereas serum glucose during the two sessions was similar (5.0 +/- 0.2 vs. 4.8 +/- 0.1 mM, NS). Identical fluid volumes were infused during the two sessions (1767 +/- 197 ml/7 h), and urine outputs did not differ significantly (1615 +/- 309 vs. 1035 +/- 248 ml/7 h). The TER of albumin was greater in all five men after hyperinsulinemia than after saline infusion (18.3 +/- 2.7 vs. -2.8 +/- 2.3%/h, P = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

In vivo evaluation of a phosphorylcholine coated cardiopulmonary bypass circuit

A complete phosphorylcholine coated cardiopulmonary bypass circuit, including the Dideco D901 oxygenator, was tested for gas transfer, blood path resistance, and biocompatibility in a standardized setting. Blood compatibility was tested by measuring complement and platelet activation. Three dogs (mean body weight 28 +/- 3 kg) were placed on cardiopulmonary bypass at a flow rate of 600 mL/min during 6 hours. The animals were weaned from cardiopulmonary bypass and sacrificed electively after 7 days. Oxygen and carbon dioxide transfer were 26.6 +/- 2.4 mL/min and 33.0 +/- 1.9 mL/min, respectively. Mean pressure drop across the oxygenator was 52.6 +/- 0.2 mmHg. The respective baseline values for thromboxane B2, prostaglandin E2 and platelet factor 4 were 1817 +/- 283 pg/mL, 12783 +/- 2109 pg/mL, and 0.35 +/- 0.08 IU/mL. Thromboxane B2 and prostaglandin E2 increased slightly to 2881 +/- 868 pg/mL and 18083 +/- 3144 pg/mL at 30 minutes of bypass, whereas platelet factor 4 values remained stable curing the procedure. Concentrations of complement split products C5a were only mildly increased. After use scanning electron microscopy was performed on the inner housing, heat exchanger, and outer surface of the hollow fibers. No thrombi nor organized cellular deposits were found on any of the components. Phosphorylcholine coating of CPB seems to be very promising regarding platelet activation and complement activation.     

Gas-exchange function of a preprimed pediatric oxygenator stored for one year for emergency cardiopulmonary bypass

To save priming time and perform more rapid initiation of emergency cardiopulmonary bypass for acute cardiopulmonary failure, an extracorporeal circuit with a hollow-fiber oxygenator (EL-2000 for pediatric use; Kurary Co. Ltd., Osaka, Japan) was preprimed, and the gas-exchange function was evaluated after 1 year of storage. EL-2000 has a dense polyolefin membrane with a surface area of 0.3 m2. When the bypass flow rates were 250, 500, 1,000, and 1,500 ml/min with 100% oxygen at the same flow rate as the bypass blood flow (namely, V/Q = 1) to the oxygenator, oxygen transport rates of the stored oxygenator were 19.6 +/- 0.3, 38.3 +/- 0.41, 64.4 +/- 0.9, and 76.4 +/- 2.7 ml/min (n = 5, mean +/- SD), respectively. PCO2 differences between pre- and postoxygenator blood (delta PCO2) were 18.6 +/- 1.4, 12.0 +/- 1.6, and 4.4 +/- 1.2 mm Hg at V/Q = 1 and the same bypass blood flow rates, respectively, excluding 1,500 ml/min, the data for which were excluded because of preparatory failure. PCO2 removal indices (defined as the ratio of delta PCO2 to PCO2 in preoxygenator blood) were 0.45 +/- 0.03, 0.29 +/- 0.12, and 0.10 +/- 0.03, respectively. Though the evaluation was done using only a single oxygenator, we feel strongly that the gas-exchange function of the preprimed dense-membrane hollow fiber oxygenator will be preserved even after 1 year of storage.     

Effects of exogenous endothelin-1 application on liver perfusion in native and transplanted porcine livers

PURPOSE: This study was designed to assess and differentiate the impact of progressivly increasing portal venous endothelin-1 (ET) plasma concentrations on hepatic micro- and macroperfusion of native porcine livers (Group A) and liver grafts after experimental transplantation (Group B). METHODS: A standardized gradual increment in systemic ET plasma concentration (0-58 pg/ml) was induced by continuous ET-1 infusion into the portal vein in both groups (A: n = 10, B: n = 10). Control animals received only saline (n = 5, each group). Hepatic microcirculation (HMC) was quantified by thermodiffusion electrodes, hepatic artery flow (HAF), and portal venous flow (PVF) by Doppler flowmetry. RESULTS: No changes in ET or perfusion parameters were observed in controls. The mean ET level after orthotopic liver transplantation (OLT) in Group B was elevated (baseline: 3.8 +/- 2.4 pg/ml) compared with Group A (2.8 +/- 1.9 pg/ml). With rising ET levels HAF decreased progressively in Group A from 205 +/- 97 (baseline) to 160 +/- 72 ml/min, and in Group B from 161 +/- 87 to 146 +/- 68 ml/min. PVF decreased in Group A from 722 +/- 253 to 370 +/- 198 ml/min, and in Group B from 846 +/- 263 to 417 +/- 203 ml/min. Baseline HMC in Group A was 86 +/- 15 and decreased significantly to 29 +/- 9 ml/100 g/min, and baseline MC in Group B was 90 +/- 22 and decreased to 44 +/- 32 ml/100 g/min. No significant alteration in systemic circulation was noted at the ET concentrations investigated. CONCLUSIONS: Significant impairment of hepatic micro- and macrocirculation was detected after induction of systemic ET levels above 9.4 pg/ml both in native and in transplanted livers. Disturbance of HMC was caused predominantly by reduction of portal venous flow, while the effect of ET on HAF was less pronounced. Characteristics of flow impairment in transplanted and native livers were analogous after short cold ischemic graft storage (6 h).     

Beneficial effect of intrarenal verapamil in human acute renal failure

Cellular Ca2+ influx during the reperfusion period after an ischemic insult has been proposed to be a crucial pathogenetic factor in the development of experimental acute renal failure (ARF). The present study, therefore, examined the potential beneficial effect of intrarenal verapamil, a calcium entry blocking agent, on ARF in patients. Twelve patients were enrolled in the study. Six ARF patients (experimental group)--ARF caused by malaria (4 patients) and leptospirosis (2 patients)--had a catheter placed in their renal artery; verapamil was infused at 100 micrograms/min for 3 h and intravenous furosemide, 0.8 mg/kg/h x 24 h was also administered. Another six ARF patients (control group)--ARF caused by malaria (5 patients) and leptospirosis (1 patient)--were treated with intravenous furosemide alone. Baseline renal function was comparable in both groups; GFR (3.16 +/- 3.24 vs 0.7 +/- 1.5 mL/min, NS), serum creatinine (Scr), (9.1 +/- 2.1 vs 11.3 +/- 2.2 mg/dL, NS), and urine volume (V) (41.79 +/- 4.77 vs 34.54 +/- 13.52 mL/h, NS), were comparable in the experimental and control groups. Twenty-four hours posttreatment, the increment of GFR (9.66 +/- 4.25 vs 1.32 +/- 0.50 mL/min, P less than .02) and V (181.8 +/- 61.7 vs 79 +/- 18 mL/h, P less than .04), were significantly greater in the experimental group as compared to the control group. The course of ARF was also shorter in the experimental group (6.5 +/- 2.1 vs 13 +/- 1.1 days, P less than .05), who also required less dialysis. Thus, combination of a renal arterial infusion of verapamil and intravenous furosemide significantly improves the renal function in tropical ARF as compared to intravenous furosemide alone.     

Prognosis of malaria associated severe acute renal failure in children

Between January and December 1996, we observed 64 children (mean age 8.3 years range 4.2 to 11.2 years) who required dialysis for severe acute renal failure secondary to Falciparum Malaria. All received anti malarial therapy and other supportive therapy as well as peritoneal dialysis. Out of these 28 died (43.8%). The children who died (Group I) compared to those who survived (Group II) differed significantly in age (mean +/- SD) (7.2 +/- 1.3 years vs. 9.2 +/- 2.1 years P < 0.05), plasma creatinine at presentation (645 +/- 104 mumol/L vs. 438 +/- 87 mumol/L P < 0.05), plasma bilirubin (2.1 +/- 0.3 mg/dL vs. 1.2 +/- 0.2 mg/dL P > 0.02) systolic BP (50 +/- 11 mmHg vs. 90 +/- 12 mmHg P0 < 0.01), diastolic BP (20 +/- 4 mmHg vs. 60 +/- 9 mmHg P < .01) .Hb level 5.3 +/- 0.4 g/dL vs. 8 +/- 1.3 gm/dL P < .02), time from diagnosis to referral (5.3 +/- 1.3 days vs. 8.9 +/- 2.1 days P < .05) and urine output (200 +/- 49 mL/24 h vs. 600 mL +/- 131 mL P < .01). There was no significant difference in gender, alanine transaminase (ALT) level, degree of fever, plasma Na or plasma K. Diarrhea was present in 29% of the children who died and in only 11% of those who survived (P > 0.05) and splenomegaly was found in 3% and 18% respectively (PO > .05).