糖尿病氧化应激的研究进展及其与糖尿病肾病的关系

多种因素参与了糖尿病中的氧化应激损伤，糖尿病肾病的发生发展与氧化应激密切相关，他丁类药物、血管紧张素转换酶抑制剂和血管紧张素Ⅱ受体拮抗剂均有抗氧化效应进而能延缓糖尿病肾病的发生发展。     

缬沙坦与苯那普利治疗慢性肾衰竭临床观察

血管紧张素Ⅱ受体(AT1型)拮抗剂(angiotensinⅡreceptor antagonist,ARA)是一种新型降压药，它对于慢性肾衰竭伴高血压患者的降压作用及肾脏保护作用，临床报道不多。血管紧张素转换酶抑制剂(angiotensin convertin enzyme inhibitor,ACEI)有降压和保护肾脏作用已有定论，我们应用血管紧张素Ⅱ受体拮抗剂缬沙坦(商品名代文)与ACEI类药物苯那普利(商品名洛汀新)进行对比，观察治疗前后血压、尿蛋白和肾功能的变化，了解血管紧张素Ⅱ受体拮抗剂的降压作用及肾功能保护作用。     

血管紧张素Ⅱ与红系造血

血管紧张素Ⅱ是肾素血管紧张素系统(RAS)的一种主要活性物质，血管紧张素转换酶抑制剂及血管紧张素Ⅱ受体拮抗剂在调节机体血压、改善微循环方面具有重要作用。近年来，许多学者发现血管紧张素Ⅱ促进红系造血，而其受体拮抗剂抑制红系造血。探讨其机制将对红系造血以及肾性贫血的治疗有广阔的前景。     

阻断血管紧张素Ⅱ与肾脏保护

在进行性肾脏损害过程中血管紧张素Ⅱ升高是重要致病因素之一，血管紧张素转换酶抑制剂和血管紧张素Ⅱ的Ⅰ型受体拮抗剂在不同水平抑制血管紧张素Ⅱ的作用。本文对比了二者肾脏保护作用机制的异同及已有的动物实验和临床研究     

阻断血管紧张素Ⅱ与肾脏保护

在进行性肾脏过程中血管紧张素Ⅱ升高是重要致病因素之一，血管紧张素转换酶抑制剂和血管紧张素的Ⅱ的Ｉ型受体拮抗剂在不同水平抑制血管紧张素Ⅱ的作用。本文对比了二者肾脏保护作用机制的异同及已有的动物实验和临床研究。     

血管紧张素Ⅱ与红系造血

血管紧张素Ⅱ是肾素血管紧张素系统 (RAS)的一种主要活性物质 ,血管紧张素转换酶抑制剂及血管紧张素Ⅱ受体拮抗剂在调节机体血压、改善微循环方面具有重要作用。近年来 ,许多学者发现血管紧张素Ⅱ促进红系造血 ,而其受体拮抗剂抑制红系造血。探讨其机制将对红系造血以及肾性贫血的治疗有广阔的前景     

小剂量维生素D受体激活剂(骨化三醇)对血液透析患者血管紧张素Ⅱ和微炎症的影响

目的 探讨小剂量维生素D受体激活剂(骨化三醇)对血液透析患者血压、血管紧张素Ⅱ和微炎症的影响.方法 20例血液透析患者应用骨化三醇(0.25μg/d)治疗,分别于用药前、用药4、8周观察患者收缩压、舒张压、血浆血管紧张素Ⅱ、超敏C反应蛋白和白细胞介素6水平.结果 治疗4周后,患者收缩压与治疗前比较差异有统计学意义(P＜0.05)；治疗4周后,患者血浆血管紧张素Ⅱ水平与治疗前比较差异有统计学意义(P＜0.05)；治疗8周后,患者血浆超敏C反应蛋白水平与治疗前比较差异有统计学意义(P＜0.01)；治疗4、8周后,患者血浆白细胞介素6水平与治疗前比较差异有统计学意义(P＜0.01).结论 小剂量维生素D受体激活剂(骨化三醇)对维持性血液透析患者可以明显降血压、抑制血管紧张素Ⅱ和抗炎症作用.     

连续性血液透析滤过联合腹水浓缩回输治疗肝肾综合征的研究

目的探讨连续性血液透析滤过联合腹水浓缩回输治疗肝肾综合征的疗效。方法选取27例肝肾综合征并大量腹水患者,采用连续性血液透析滤过联合腹水浓缩回输治疗,比较治疗前、后患者的体质量、腹围、尿量、血浆内皮素1、血浆血管紧张素Ⅱ、清蛋白、血肌酐、尿素氮、血碳酸氢根以及患者的精神、饮食等一般情况变化。结果采用联机连续性血液透析滤过联合腹水浓缩回输治疗后,患者血肌酐、尿素氮、血浆内皮素1及血浆血管紧张素Ⅱ明显下降,酸中毒和低钠血症得到纠正,清蛋白升高,体质量、腰围明显缩小,尿量增加。结论该疗法可降低肝肾综合征并发症,提高生存率。     

血管紧张素Ⅱ与胰岛素抵抗

胰岛素抵抗是多种疾病如2型糖尿病、多囊卵巢综合征等发病的关键环节。研究显示，使用血管紧张素转换酶抑制剂（ACEI）或血管紧张素Ⅱ受体拮抗剂（AT1RA）阻断血管紧张素Ⅱ（AngⅡ）的效应可以改善胰岛素敏感性，降低新发糖尿病的发生率。我们就AngⅡ与胰岛素抵抗的相关基础及临床研究作一综述。     

不同血液净化治疗方法对终末期肾病难治性高血压患者的临床观察

目的 不同血液净化方法治疗维持性血液透析患者难治性高血压的疗效观察.方法 60例终未期肾病难治性高血压患者按随机数字表法分为血液透析组,血液透析联合血液透析滤过组,血液透析联合血液灌流组,每组15例患者.血液透析联合血液透析滤过再联合血液灌流组,观察治疗前及治疗16周后所有患者血压变化及肾素、血管紧张素Ⅱ、全段甲状旁腺激素的水平变化.结果 各组患者治疗后血压及肾素、血管紧张素Ⅱ、全段甲状旁腺激素水平与治疗前比较差异有统计学意义(P＜0.05),而治疗组中血液透析联合血液透析滤过再联合血液灌流组与血液透析联合血液灌流组、血液透析联合血液透析滤过组治疗后比较,血压变化及肾素、血管紧张素Ⅱ、全段甲状旁腺激素水平与治疗前比较差异有统计学意义(P＜0.05).结论 在维持血液透析的治疗基础上联合应用血液透析滤过及血液灌流能有效的控制终未期肾病难治性高血压.     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

A Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.