20%长链脂肪乳剂对脑室注射局麻药引起的氨基酸神经递质失衡的影响

目的探讨20%长链脂肪乳剂对脑室注射局麻药引起的氨基酸神经递质失衡的影响。方法选择30只健康成年雄性SD大鼠,随机分为两组:正常组(C组,n=10)和局麻药中毒组(L组,n=20)。L组按处理不同分为对照组(S组,n=10)和脂肪乳治疗组(I组,n=10)。L组大鼠经右侧侧脑室以50μl/min速度注入0.75%左旋布比卡因,脑电出现惊厥波时持续输注20%长链脂肪乳剂0.25ml·kg-1·min-1(I组)或生理盐水(S组),C组大鼠不予任何处理,持续监测三组大鼠EEG、ECG和SpO2。观察三组大鼠惊厥持续时间、左旋布比卡因惊厥阈值及建模后24h死亡率,同时检测脑脊液中神经递质谷氨酸(Glu)和γ-氨基丁酸(GABA)浓度以及海马区N-甲基-D-天冬氨酸受体1(NMDAR1)的表达,计算Glu和GABA浓度比值,并分析Glu与NMDAR1表达的相关性。结果 S组大鼠惊厥持续时间明显长于,建模后24h死亡率明显高于,惊厥阈值明显低于I组(P0.05)。S组和I组大鼠脑脊液Glu与GABA浓度、Glu/GABA及海马区NMDAR1的表达均明显高于C组(P0.05),S组大鼠脑脊液Glu浓度、Glu/GABA及海马区NMDAR1的表达均明显高于I组(P0.05),脑脊液中Glu含量与NMDAR1呈正相关(r=0.884,P0.01)。结论静脉输注20%长链脂肪乳剂可通过有效改善局麻药引起的脑内Glu和GABA失衡而发挥抗中枢神经毒性作用。     

静脉麻醉药抑制利多卡因致大鼠惊厥作用的比较

目的比较静脉麻醉药丙泊酚、依托咪酯、咪达唑仑及硫喷妥钠拮抗利多卡因致大鼠惊厥的作用。方法雄性Wistar大鼠36只,体重(250±20)g,随机均分为六组:空白对照组(C组)、利多卡因组(L组:利多卡因4mg·kg-1·min-1)、利多卡因+丙泊酚组(P组:利多卡因+丙泊酚12.5mg/kg)、利多卡因+依托咪酯组(E组:利多卡因+依托咪酯1.85mg/kg)、利多卡因+咪达唑仑组(M组:利多卡因+咪达唑仑0.65mg/kg)和利多卡因+硫喷妥钠组(T组:利多卡因+硫喷妥钠30.85mg/kg),惊厥后2h处死大鼠,取出脑组织分离双侧海马,一侧用于检测c-fos阳性细胞蛋白的表达。另一侧用于测定一氧化氮(NO)含量及一氧化氮合酶(NOS)活性。结果除C组外,其它五组大鼠均出现了惊厥,给予静脉麻醉药抑制惊厥,五组惊厥持续时间差异无统计学意义。L、P、E、M和T组c-fos阳性细胞表达、NO含量和NOS活性显著高于C组(P<0.05);P、E、M和T组c-fos阳性细胞表达、NO含量及NOS活性均显著降低于L组(P<0.05);M、T组c-fos阳性细胞表达、NO含量及NOS活性显著低于P、E组(P<0.05)。结论静脉麻醉药咪达唑仑、丙泊酚、依托咪酯及硫喷妥钠均可有效抑制利多卡因致惊厥作用,其中咪达唑仑与硫喷妥钠效果更显著。     

不同剂量右美托咪定预注对利多卡因神经毒性的影响

目的 比较不同剂量右美托咪定(dexmedetomidine,Dex)预注对利多卡因致白兔中枢神经毒性的影响及可能机制. 方法 将40只新西兰白兔按随机数字表法分为4组(A、B、C、D组),每组10只:A组通过颈内静脉泵入含Dex 10 μg/kg的生理盐水8 ml,10 min后以4 mg· kg-1· min-1泵入利多卡因直到出现惊厥;B组泵入含Dex 5 μg/kg的生理盐水8 ml,同法泵入利多卡因;C组泵入等量生理盐水,同法泵入利多卡因;D组只泵入生理盐水8 ml.于白兔惊厥时抽血测利多卡因浓度,记录利多卡因剂量及发生惊厥时间,测脑组织天冬氨酸(aspartate,Asp)、谷氨酸(glutamic acid,Glu)、甘氨酸(glycine,Gly)、γ-氨基丁酸(γ-aminobutyric acid,GABA)的含量. 结果 产生中枢神经毒性所需利多卡因剂量、利多卡因血药浓度及发生惊厥时间,A组[分别为:(240±48) mg,(6.4±0.8)μg/kg,(822±122)s]、B组[分别为:(230±51) mg,(6.3±0.5)μg/kg,(802±114)s]较C组[分别为:(137±37) mg,(5.4±0.6) μg/kg,(510±76)s]明显增加,差异有统计学意义(P＜0.05);Asp、Glu、Gly、GABA的含量,A组[分别为:(3.5±1.0)、(4.0±1.9)、(10.1±1.9)、(16.5±2.2) μmol/g]、B组[分别为:(3.7±0.8)、(4.2±1.9)、(11.4±2.2)、(17.4±2.4) mol/g]、C组[分别为:(4.7±1.0)、(6.8±1.9)、(13.7±1.9)、(20.9±3.4) μmol/g]明显高于D组[分别为:(1.5±0.8)、(2.4±1.2)、(4.7±1.6)、(5.7±2.8) μmol/g],差异有统计学意义(P＜0.05),而C组又明显高于A、B组(P＜0.05). 结论 预注Dex可以延缓利多卡因致惊厥反应的发生,增加利多卡因神经毒性的阈值,对中枢神经有一定的保护作用.     

氯胺酮对脂多糖诱导下人脐静脉内皮细胞活化的影响

目的 观察氯胺酮和N-甲基-D-天门冬氨酸(NMDA)受体非竞争性拮抗剂MK-801对脂多糖(LPS)刺激下人脐静脉内皮细胞(HUVECs)胞间粘附分子-1(ICAM-1)表达及核因子-kappa B(NF-kB)易位表达的影响。方法 采用Jaffe方法培养的HUVECs随机分为10组:对照组(C组,RPMI-1640),LPS组(L组,LPS1μg/ml),氯胺酮组(K组,依浓度不同分为KⅠ、KⅡ、KⅢ、KⅣ亚组,即氯胺酮12.5、25.0、100、300μmol/L LPS1μg/ml),MK-801组(M组,依浓度不同分为MⅠ、MⅡ、MⅢ、MⅣ亚组,即MK-801 1.25、2.50、10、30μmol/L LPS1μg/ml)。在37℃、5％CO_2中孵育18h后,用流式细胞仪检测ICAM-1的表达阳性率。NF-kB易位表达的测定分组处理同上,在LPS1μg/ml刺激2h后,用免疫组化(SP)方法测定内皮细胞中NF-kB p65亚基的表达。结果 KⅡ、KⅢ、KⅣ亚组可抑制LPS作用下HUVECs表面ICAM-1的表达和细胞内部NF-kB的易位表达(P<0.05),且两者的变化呈正相关(r=0.985,P<0.01)。M组各亚组对LPS作用后HUVECs表面ICAM-1的表达和NF-kB的易位表达无明显影响(P>0.05)。结论 氯胺酮对炎症反应中内皮细胞的活化具有抑制作用,但并非通过NMDA受体途径。     

MK-801对梗阻性黄疸大鼠中枢神经抗氧化应激系统的影响

目的探讨MK-801对梗阻性黄疸大鼠中枢神经抗氧化应激系统的影响。方法 20只大鼠随机均分为假手术组、对照组、MK-801低剂量组和MK-801高剂量组4组,后3组为梗阻性黄疸模型组。MK-801低剂量组和MK-801高剂量于梗阻性黄疸模型建模术后第2天起分别腹腔注射0.025 mg/(kg·d)和0.25 mg/(kg·d)的MK-801,共10 d;假手术组和对照组则以等容量生理盐水同时点注射。4组大鼠于术后3 d采尾部静脉血检查直接胆红素(DBIL)和总胆汁酸(TBA)以确定模型制作是否成功,术后10 d处死大鼠并取大脑皮质按试剂盒要求行丙二醛(MDA)、过氧化氢酶(CAT)、总超氧化物歧化酶(T-SOD)及总抗氧化能力(T-AOC)含量或活性测定。结果1建模术后3 d,对照组、MK-801低剂量组和MK-801高剂量组大鼠的DBIL和TBA水平明显升高,且出现全身皮肤黄染,提示梗阻性黄疸模型建模成功。2对照组、MK-801低剂量组和MK-801高剂量组的MDA含量均明显高于假手术组(P0.05),MK-801低剂量组和MK-801高剂量组MDA含量则明显低于对照组(P0.05),MK-801低剂量组和MK-801高剂量组间MDA含量的差异无统计学意义(P0.05)。3对照组CAT活性低于假手术组(P0.05),MK-801低剂量组和MK-801高剂量组的CAT活性明显高于假手术组及对照组(P0.05),MK-801低剂量组和MK-801高剂量组之间CAT活性差异无统计学意义(P0.05)。4对照组T-SOD活性明显低于假手术组(P0.05),MK-801低剂量组T-SOD活性则明显高于对照组(P0.05),MK-801高剂量组T-SOD活性高于对照组但低于MK-801低剂量组(P0.05)。5对照组、MK-801低剂量组和MK-801高剂量组的T-AOC明显高于假手术组(P0.05)。MK-801低剂量组和MK-801高剂量组的T-AOC又明显高于对照组(P0.05),但MK-801低剂量组和MK-801高剂量组间T-AOC的差异无统计学意义(P0.05)。结论梗阻性黄疸时机体中枢神经系统存在氧化应激反应,机体通过增加CAT等抗氧化应激损伤酶类的表达使抗氧化应激损伤能力增强。MK-801使梗阻性黄疸所致大鼠中枢神经系统氧化应激损伤过程中脂质过氧化程度降低,并可提高SOD及CAT的活性及机体总抗氧化应激能力;高剂量的MK-801与低剂量的MK-801相比其效果并未明显增加,反而使T-SOD活性比低剂量组降低。具体机理需要进一步研究。     

低浓度利多卡因对大鼠海马CA1区缺氧神经元持续钠电流的影响

目的观察低浓度利多卡因对大鼠海马CA1区缺氧神经元持续钠电流的影响,探讨其对缺血脑损伤保护作用的机制。方法酶消化法急性分离SD大鼠海马CA1区锥体细胞,随机分为7 组(n=10):缺氧组(C组)、利多卡因1μmol·L-1组(L1组)、3μmol·L-1组(L2组)、6μmol·L-1组(L3组)、10 μmol·L-1组(L4组)、20μmol·L-1组(L5组)、30μmol·L-1组(L6组)。以全细胞膜片钳技术记录各组缺氧前持续钠电流的基础值后,C组以无糖缺氧灌流液、L1-6组以含有不同浓度利多卡因的无糖缺氧灌流液在20 s内快速置换灌流液,建立体外神经元缺氧模型。记录缺氧5 min时各组神经元的持续钠电流。结果与基础值比较,各组神经元在缺氧5 min时持续钠电流均增大(P<0.01)。在缺氧5 min 时,L1-6组持续钠电流均低于C组,L2-6组均低于L1组,L3-6组均低于L2组,L4-6组均低于L3组(P< 0.01)。结论低浓度利多卡因能抑制大鼠海马CA1区神经元缺氧引起的持续钠电流增加,该作用在10 μmol·L-1时达到最大。     

利多卡因对脂多糖诱导的巨噬细胞高迁移率族蛋白B1 mRNA表达的影响

目的 观察利多卡因对脂多糖(LPS)诱导的大鼠腹腔巨噬细胞高迁移率族蛋白B1(HMGB1) mRNA表达的影响.方法 取雄性Wistar大鼠腹腔巨噬细胞,置6孔细胞培养板中培养3～5 d后,分为四组:脂多糖组(LPS组),LPS刺激浓度为100 ng/ml;LI组,于LPS刺激前30 min给予利多卡因(终浓度为20 μg/m1)预处理;L2组,于LPS刺激后30 min给予同等剂量的利多卡因处理;L3组分别于LPS刺激后30 min、6、12、18 h给予同等剂量的利多卡因处理.LPS刺激24 h后收取细胞,采用RT-PCR检测细胞HMGB1 mRNA的表达.结果 与LPS组比较,L1、L2、L3组HMGB1 mRNA表达均有不同程度下降(P<0.01).L3组HMGB1 mRNA表达下降程度最大,明显低于L1、L2组(P<0.01).结论 利多卡因能够抑制LPS诱导的体外培养大鼠腹腔巨噬细胞HMGB1 mRNA的表达.     

吗啡对电刺激坐骨神经诱发大鼠脊髓背角突触长时程增强的影响

目的 评价吗啡对电刺激坐骨神经诱发大鼠脊髓背角突触长时程增强(LTP)的影响.方法 雄性SD大鼠27只,日龄60～90 d,体重180～200 g,随机分为4组:对照组(C组,n=7)、吗啡组(M组,n=7)、纳洛酮组(N组,n=6),纳洛酮+吗啡组(MN组,n=7).麻醉下分离左侧坐骨神经,记录电极插入左侧T13～L1脊髓背角,刺激电极刺激左侧坐骨神经,给予15 V、0.5 ms、1/60 Hz单个方波电刺激30 min以诱发场电位,抽取生理盐水10 μl、吗啡10 μl(15 μg/μl)、纳洛酮10 μl(2.5 μg/μl)、纳洛酮(2.5 μg/μl)和吗啡(15 μg/μl)各5 μl的混合液,在脊髓上方3～5 mm,经2 min内缓慢滴注,给药后5 min时,给予4串高频高强度强直电刺激后,再给予15 V、0.5 ms、1/60 Hz单个方波电刺激210 min,记录强直刺激前30 min、强直刺激后即刻～30 min、35～60 min、65～120 min、125～210 min时段平均场电位幅值及潜伏期.结果 与C组比较,M组和MN组平均场电位幅值降低,潜伏期延长(P<0.05或0.01),N组上述指标差异无统计学意义(P>0.05).与M组比较,MN组平均场电位幅值升高,潜伏期缩短(P<0.05或0.01).与强直刺激前30 min比较,C组和N组在强直刺激后各时段平均场电位幅值升高,潜伏期缩短,M组在强直刺激后各时段平均场电位幅值降低,潜伏期延长,MN组在强直刺激后即刻～30 min和35～60 min时段平均场电位幅值升高,强直刺激后即刻～30 min时段潜伏期缩短,65～120 min和125～210 min时段平均场电位幅值降低,潜伏期延长(P<0.05或0.01).结论 吗啡可抑制电刺激坐骨神经诱发大鼠脊髓背角突触LTP,可能是其抑制中枢敏化的机制之一.     

地卓西平马来酸对大鼠脊髓损伤后c-fos、热休克蛋白27表达的影响

我们通过检测脊髓组织细胞凋亡细胞及脊髓组织中热休克蛋白27(HSP27)、c-fos基因的表达,探讨地卓西平马来酸(MK-801)在急性脊髓损伤中的保护机制. 一、材料和方法 1.材料:健康雄性清洁级SD大鼠,MK-801,膜联蛋白V-异硫氰酸荧光素(Annexin V-FITC)/碘化丙锭(PI)细胞凋亡检测试剂盒,c-fos免疫组织化学试剂盒、HSP27免疫组织化学试剂盒. 2.动物分组与动物模型建立:20只成年清洁级SD大鼠随机平均分为脊髓损伤(SCI)组和MK-801组.按改良Allen重物打击模型制作成急性脊髓损伤模型.打击后0.5h,脊髓SCI组腹腔注射生理盐5 ml/kg,MK-801组腹腔注射5 mg/kg.     

利多卡因致大鼠惊厥时海马神经元含NR2B亚基的N-甲基-D-天门冬氨酸受体表达的变化

目的 评价利多卡因致大鼠惊厥时海马神经元含NR2B亚基的N-甲基-D-天门冬氨酸(NMDA)受体表达的变化.方法 健康雄性SD大鼠24只,体重220～250 g,6月龄,采用随机数字表发法,将其分为2组(n=12):生理盐水组(N组)和利多卡因组(L组).L组经尾静脉输注2％利多卡因4 mg· kg-1·min-1至大鼠发生RacineⅢ级惊厥,N组以等容量等速率生理盐水替代.于惊厥停止后即刻、6、12 h(T1～3)时取海马,采用免疫印迹和RT-PCR法检测NR2B蛋白及mRNA的表达水平.结果 与N组比较,L组NR2B蛋白及mRNA表达上调.与T1时比较,L组T2,3时NR2B蛋白及mRNA表达下调(P＜0.05).与T2时比较,L组T3时NR2B蛋白表达下调(P＜0.05).结论 利多卡因诱发大鼠惊厥时海马神经元含NR2B亚基的NMDA受体表达上调,该变化可能与利多卡因诱发惊厥发作有关.     

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 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.     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.     

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.     

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.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.