Acute,subacute and subchronic inhalation toxicity of cyclopentene

Summary Cyclopentene was evaluated for its acute, subacute and subchronic inhalation toxicity. The LC₅₀ values for male and female rats after 4-hr inhalation of cyclopentene vapours are higher than 8110 ppm. The daily exposure of rats to concentrations of 870 and 8110 ppm for 6 hrs/day, 5 times/week for 3 weeks resulted only in decreased body weight gains of the female animals exposed to concentrations of 8110 ppm. Male and female rats were exposed to daily concentrations of 112, 317 or 1139 ppm for 6 hrs/day, 5 times/week for 12 weeks. These concentrations were tolerated without any detectable toxicological effects. Short-term exposure of humans revealed a tolerable concentration of 10–15 ppm only. The results are discussed in relation to the possibility of establishing a maximal allowable concentration.We wish to express our thanks to Miss Anneliese Eben for the determinations of the concentrations in the air.     

Interactions of IgM ABO antibodies and complement with methoxy-PEG-modified human RBCs

BACKGROUND: RBCs modified with cyanuric chloride activated methoxy-PEG (CmPEG; 5000 Da) are less immunogenic than untreated RBCs, and their use thus may reduce the risk of alloimmunization in chronically transfused patients. STUDY DESIGN AND METHODS: To further examine the potential utility of CmPEG-RBCs, the effects of derivatization on an arm of the immune system that plays an important role in transfusion rejection-the complement system--were determined. RESULTS: When CmPEG-RBCs were incubated in autologous or heterologous ABO-matched serum, no classical or alternative pathway consumption was found, no C3a was generated, no cell-bound C3b or C9 was detected, and no cell lysis occurred. Cell-bound complement regulation was normal for CmPEG-RBCs, as determined by acidified serum or reactive lysis assays. CmPEG-RBCs differed from control RBCs only when incubated in ABO-mismatched serum. In that case, CmPEG modification failed to protect against ABO antibody-dependent complement-mediated lysis. Indeed, cell lysis was actually enhanced at CmPEG concentrations >1.0 mM. CONCLUSION: The enhanced lysis of CmPEG-RBCs in ABO-mismatched serum correlated with increased IgM binding and C3a generation and elevated C3b and C9 membrane deposition. While PEG modification effectively blocks non-ABO antigens, these data show that ABO matching is still required. Once ABO-matched, these modified RBCs retain great potential for the prevention of alloimmunization.     

Influence of sepsis on sevoflurane minimum alveolar concentration in a porcine model

Sevoflurane is widely used in anaesthetic protocols for patientsundergoing surgical procedures. However, there are no reportson the influence of sepsis on minimum alveolar concentrationof sevoflurane (MAC_SEV) in animals or in humans. The aim ofthis study was to test the hypothesis that sepsis could alterthe MAC_SEV in a normotensive septic pig model. Twenty young,healthy pigs were used. After they had received 10 mg kg^–1of ketamine i.m. for premedication, anaesthesia was establishedwith propofol 3 mg kg^–1 and the trachea wasintubated. Sevoflurane was used as the sole anaesthetic agent.Baseline haemodynamic recording included electrocardiography,carotid artery blood pressure and a pulmonary thermodilutioncatheter. Baseline MAC_SEV in each pig was evaluated by pinchingwith a haemostat applied for 1 min to a rear dewclaw. MAC_SEVwas determined using incremental changes in sevoflurane concentrationuntil purposeful movement appeared. Pigs were assigned randomlyto two groups: the saline group (n=10) received a 1-h i.v. infusionof sterile saline solution while the sepsis group (n=10) receiveda 1-h i.v. infusion of live Pseudomonas aeruginosa. Epinephrineand hydroxyethylstarch were used to maintain normotensive andnormovolemic haemodynamic status. In both groups, MAC_SEV wasevaluated 5 h after infusion. Significant increases inmean artery pulmonary pressure, filling, epinephrine and vascularpulmonary resistances occurred in the sepsis group. MAC_SEV forthe saline group was 2.4% [95% confidence interval (CI) 2.1–2.55%]and the MAC_SEV for the sepsis group was 1.35% (95% CI 1.2–1.45%,P<0.05). These data indicate that MAC_SEV is significantlydecreased in this normotensive septic pig model. Br J Anaesth 2001; 86: 832–6     

硬膜外麻醉复合吸入全麻对异氟醚最低肺泡清醒浓度的影响

目的观察硬膜外麻醉复合吸入全麻对异氟醚最低肺泡清醒浓度（MAC—awake）的影响。方法200例腹部外科择期手术病人，随机分为两组：Ⅰ组（单纯吸入全麻组，100例）和EI组（硬膜外麻醉复合吸入全麻组，100例）。EI组先给予硬膜外麻醉。两组均选择异丙酚和维库溴铵诱导进行气管内插管，术中均用异氟醚、维库溴铵维持麻醉；均用Evans麻醉深度评分法维持术中麻醉深度在2～4分之间。记录异氟醚MAC-awake值；苏醒时间；潮气量（Tv）、呼吸频率（RR）、血压（BP）、心率（HR）、动脉血二氧化碳分压（PCO2）、动脉血氧分压（PO2）、肌松及有无躁动情况。结果EI组异氟醚／VIAC—awake值明显低于Ⅰ组，苏醒时间却更长（P〈0．05）；TV、RR、PCO，、肌松（TOF值：T4／T1〉75％）差异无显著性意义（P〉0．05）；BP、HR较Ⅰ组平稳（P〈0．05）；躁动例数（2例）明显少于I组（29例）。结论硬膜外麻醉复合吸入麻醉能降低异氟醚最低肺泡清醒浓度；维持循环系统稳定；减少术后躁动。     

Microglia activation during neuroregeneration in the adult vertebrate brain

Brain injury and neuronal loss leads to an inflammatory response, which is initiated by the innate immune system. To what extent this immune response is beneficial or detrimental for neurogenesis and regeneration is unclear. We addressed this question during regeneration of dopamine neurons in the adult salamander brain. In contrast to mammals, ablation of dopamine neurons evokes robust neurogenesis leading to complete histological and functional regeneration within four weeks in salamanders. Here we show that similarly to mammals, ablation of dopamine neurons causes microglia activation and an increase in microglia numbers in the ablated areas. Furthermore, microglia numbers remain elevated compared to the uninjured brain at least six weeks after ablation. Suppression of the microglia response results in enhanced regeneration, concomitant with reduced death of dopamine neurons during the regeneration phase. Thus neuroregeneration is not dependent on the absence of an innate immune response, but the suppression of this response may be a means to promote neurogenesis in the adult vertebrate brain.     

异丙酚复合芬太尼在无痛肠镜中的临床观察

目的 探讨异丙酚复合芬太尼实施监护下麻醉管理（monitored anesthesia Care，MAC）技术，应用于肠镜检查中的有效性和安全性。方法 200例行肠镜检查者随机分为MAC组（n=100）和对照组（n=100），对照组行常规肠镜检查。MAC组以芬太尼1μg／kg静脉注射，继以异丙酚1～2mg／s速度推注，Ramsay镇静分级5级后行肠镜检查，术中5～10mg／min速度维持MAC。结果 MAC组无痛率100％，其中安静入睡98例（98％），轻微肢体活动16例（16％），明显肢体活动影响操作4例（4％），清醒时间短，不良反应少，检查中生命体征平稳。对照组病例则有不同程度的腹胀、腹痛、大声喊叫、肢体活动及其他不适，不良反应多。结论 异丙酚复合芬太尼MAC技术应用于肠镜检查，镇痛镇静效果确切，安全。     

Development of lung cancer in patients with nontuberculous mycobacterial lung disease

Background

As lung cancer development in patients with nontuberculous mycobacterial lung disease (NTM-LD) has never been reported, we investigated its incidence and clinical characteristics.

The lectin pathway of complement: Advantage or disadvantage in HIV pathogenesis?

The pattern recognition molecules of the lectin complement pathway are important components of the innate immune system with known functions in host–virus interactions. This paper summarizes current knowledge of how these intriguing molecules, including mannose-binding lectin (MBL), Ficolin-1, -2 and -3, and collectin-11 (CL-11) may influence HIV-pathogenesis. It has been demonstrated that MBL is capable of binding and neutralizing HIV and may affect host susceptibility to HIV infection and disease progression. In addition, MBL may cause variations in the host immune response against HIV. Ficolin-1, -2 and -3 and CL-11 could have similar functions in HIV infection as the ficolins have been shown to play a role in other viral infections, and CL-11 resembles MBL and the ficolins in structure and binding capacity.