不同时期抽出聚丙烯酰胺水凝胶丙烯酰胺单体含量的检测

目的探讨聚丙烯酰胺水凝胶注入动物及人体后,在体内环境作用下,经过一段时间,是否有丙烯酰胺单体释放出来.方法在不同时期从注射处抽出或取出标本,进行高压液相色谱仪外标法检测.结果小香猪半年以上标本1份,1年以上标本3份.兔6～8个月标本6份.人体乳房内抽出标本22例人26份.检测结果均＜3.6×10-6,未高出注射前标准样品检测的数值.结论初步提供在近期内未发现丙烯酰胺单体析出的结果.     

聚丙烯酰胺水凝胶中丙烯酰胺单体提取及HPLC测定

目的：建立聚丙烯酰胺水凝胶（PAMG）中丙烯酰胺（AM）单体提取及检测的高效液相色谱（HPLC）分析方法。方法：用水做提取剂对PAMG中的AM进行提取，采用Oasis HLB 6cc和Varian Bond Elut—Accucat固相萃取柱对样品进行纯化，以HPLC测定其含量.结果：未植入人体PAMG中AM含量为0．2～0．8μg／ml，从人体中取出PAMG中AM含量均低于最小检出限0．05μg／m1。结论：本方法适用于PAMG中AM单体含量的检测，具有操作简单、灵敏、准确等优点。     

奥美定注入小香猪体内后生殖毒性的观察

目的 观察奥美定注入小香猪体内后的生殖毒性。方法 注入奥美定后观察小香猪母代及子代的生长、健康情况，抽出奥美定检测丙烯酰胺单体含量以及抽血查染色体及微核试验观察。结果 6只母代小香猪健康，2只与公猪交配，4个月及5个月后生出9只及4只子代小猪，健康情况亦良好。在半年及1年后分别抽出奥美定检测丙烯酰胺单体没有增加，共检测9只小香猪的染色体包括母代及子代，均未发现数目畸变及结构畸变，微核试验有细微的变化，并初步反映出与用药量大小呈正相关，但超量注射的一只动物(18.5ml/kg)变化的千分值仍在正常范围内。结论 从目前几项观察与检测指标看，实验量奥美定注入小香猪体内尚不具生殖遗传毒性。     

奥美定中丙烯酰胺单体含量的分析

目的　探讨奥美定的配制材料注入兔体内 1年 ,丙烯酰胺单体含量的变化。方法　将 4只日本大耳兔分为A(2只 )、B(2只 )两组 ,A组以 10ml/kg奥美定的配制材料注入大耳兔体内 ,B组以 2ml/kg奥美定的配制材料注入大耳兔体内 ,至 12个月时取出 ,用高效液相色谱法分析丙烯酰胺单体含量。结果　奥美定中丙烯酰胺单体含量 <1.10× 10 -6g/ g ,而注入兔体内后取出的奥美定的配制材料中丙烯酰胺单体含量为 1.18× 10 -5～ 4 .88× 10 -5g/ g。结论　注入大耳兔体内的奥美定 12个月时丙烯酰胺单体含量较未注入的奥美定有所升高 ,但仍低于或接近国外同类材料中丙烯酰胺单体含量 ,因此是安全无毒性的     

奥美定中丙烯酰胺单体含量的分析

目的探讨奥美定的配制材料注入兔体内1年,丙烯酰胺单体含量的变化.方法将4只日本大耳兔分为A(2只)、B(2只)两组,A组以10 ml/kg奥美定的配制材料注入大耳兔体内,B组以2 ml/kg奥美定的配制材料注入大耳兔体内,至12个月时取出,用高效液相色谱法分析丙烯酰胺单体含量.结果奥美定中丙烯酰胺单体含量＜1.10×10-6 g/g,而注入兔体内后取出的奥美定的配制材料中丙烯酰胺单体含量为1.18×10-5～4.88×10-5 g/g.结论注入大耳兔体内的奥美定12个月时丙烯酰胺单体含量较未注入的奥美定有所升高,但仍低于或接近国外同类材料中丙烯酰胺单体含量,因此是安全无毒性的.     

奥美定注入小香猪体内后生殖毒性的观察

目的　观察奥美定注入小香猪体内后的生殖毒性。方法　注入奥美定后观察小香猪母代及子代的生长、健康情况 ,抽出奥美定检测丙烯酰胺单体含量以及抽血查染色体及微核试验观察。结果　 6只母代小香猪健康 ,2只与公猪交配 ,4个月及 5个月后生出 9只及 4只子代小猪 ,健康情况亦良好。在半年及 1年后分别抽出奥美定检测丙烯酰胺单体没有增加 ,共检测 9只小香猪的染色体包括母代及子代 ,均未发现数目畸变及结构畸变 ,微核试验有细微的变化 ,并初步反映出与用药量大小呈正相关 ,但超量注射的一只动物 (18.5ml/kg)变化的千分值仍在正常范围内。结论　从目前几项观察与检测指标看 ,实验量奥美定注入小香猪体内尚不具生殖遗传毒性     

奥美定注入小香猪体内后生殖毒性的观察

目的观察奥美定注入小香猪体内后的生殖毒性.方法注入奥美定后观察小香猪母代及子代的生长、健康情况,抽出奥美定检测丙烯酰胺单体含量以及抽血查染色体及微核试验观察.结果 6只母代小香猪健康,2只与公猪交配,4个月及5个月后生出9只及4只子代小猪,健康情况亦良好.在半年及1年后分别抽出奥美定检测丙烯酰胺单体没有增加,共检测9只小香猪的染色体包括母代及子代,均未发现数目畸变及结构畸变,微核试验有细微的变化,并初步反映出与用药量大小呈正相关,但超量注射的一只动物(18.5?ml/kg)变化的千分值仍在正常范围内.结论从目前几项观察与检测指标看,实验量奥美定注入小香猪体内尚不具生殖遗传毒性.     

丙烯酰胺单体的细胞毒性研究

目的　研究不同浓度丙烯酰胺单体在聚丙烯酰胺水凝胶中残留量的细胞毒性。方法　将不同浓度丙烯酰胺单体溶液加入到细胞培养液中培养细胞 ,通过对细胞生长和增殖的影响来评价其对细胞的潜在毒性作用。结果　丙烯酰胺单体浓度小于 1 .0 0× 1 0 - 8g/ml,无毒性 ;浓度为 1 .0 0× 1 0 - 7～ 2 .50× 1 0 - 4g/ml,轻微毒性 ;浓度大于8.33× 1 0 - 4g/ml,有明显的细胞毒性及较强的细胞毒性。结论　聚丙烯酰胺水凝胶中丙烯酰胺单体残留量最好控制在 1 .0 0× 1 0 - 7g/ml以下较为安全     

聚丙烯酰胺水凝胶注射隆乳取除术157例分析

目的探讨聚丙烯酰胺水凝胶（polyacrylamide hydrogel,PAHG）注射隆乳术后并发症分析与处理策略。方法对157例行PAHG注射隆乳术后因并发症受术者的病历资料进行回顾性分析。术前所有受术者均行MRI检查,其中23例行注射物三维重建,71例行血清丙烯酰胺单体检测,23例行PAHG中和12例行PAHG周围组织中丙烯酰胺单体含量检测,7例于PAHG清除后即时置入硅胶乳房假体。结果MRI三维重建可直观、详细地显示注射物的位置、范围、层次及完整性。7例血清、5例PAHG和3例周围组织中检测出丙烯酰胺单体。131例受术者术后效果满意。所有受术者随访3～6个月,乳房触诊均未发现硬结。7例即时置入硅胶乳房假体者乳房外形及手感良好。结论术前首选MRI检查,条件允许时可进一步行三维重建。就目前检测手段尚无PAHG在体内分解为丙烯酰胺单体的有力证据。取除手术应在直视下尽量清除注射物及周围包膜和变性组织,切忌盲视下抽吸。在受术者有强烈要求、肌肉保存完整和无炎症的的前提下,可考虑即时行硅胶乳房假体置入重建乳房形态。     

聚丙烯酰胺水凝胶注射美容的临床与组织学评估

目的　探讨聚丙烯酰胺水凝胶注射后并发症的临床与组织学特点。方法　对 1998年至 2 0 0 3年接诊的 5 2例在外院注射了聚丙烯酰胺水凝胶 ,并引起并发症患者的临床资料进行了总结与组织学研究。为了便于比较 ,另选 12例 1988年～ 1994年期间接受液态硅胶注射的患者取出的组织病理切片与之对照研究。结果　聚丙烯酰胺水凝胶注射后并发症以局部硬结最多见 ,而且多发生在注射后 1～ 2年左右时间里。人体组织对注射的聚丙烯酰胺水凝胶的反应为多核异物巨细胞增生 ,并形成肉芽肿。与液态硅胶比较 ,注射的聚丙烯酰胺水凝胶引起组织的淋巴细胞反应弱 ,材料周围的纤维包膜较薄。机体内长期存留的聚丙烯酰胺水凝胶可能会引起局部组织变性反应。结论　聚丙烯酰胺水凝胶作为软组织填充剂的安全性需要进一步研究。     

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.     

A comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.