骨髓基质干细胞移植对正常和心肌梗死大鼠心电图及心功能的影响

目的:骨髓基质干细胞移植到心肌梗死的瘢痕心肌组织中可以改善心功能,但以心电图为观察指标的研究不多。实验观察骨髓基质干细胞移植对正常和心肌梗死大鼠心电图及心功能的影响。方法:实验于2004-01/2005-03在哈尔滨医科大学完成。①实验动物:选取4周龄雄性Wistar大鼠80只,随机数字表法分为梗死移植组、正常移植组、梗死非移植组、正常非移植组,20只/组。另选取7d龄Wistar雄鼠30只作为骨髓基质干细胞的来源。②实验方法:采用密度梯度离心法获取鼠骨髓基质干细胞,配成1×109L-1的细胞悬液,使用5-氮胞苷体外诱导培养3～4周,移植前24～48h行Brdu标记。取载有细胞的盖玻片,测定钙释放时将20mmol/L的caffeine快速加在细胞表面。梗死移植组、梗死非移植组大鼠建立心肌梗死模型。造模4周后,梗死移植组将0.25mL诱导的骨髓基质干细胞悬液注射至大鼠心肌梗死后的瘢痕组织,正常移植组同法将骨髓基质干细胞悬液注射至正常心肌组织,梗死非移植组、正常非移植组注射等量不含骨髓基质干细胞的培养液基质。③实验评估:观察骨髓基质干细胞的诱导分化情况及其植入后在瘢痕心肌组织中的生存状态。测定细胞内钙离子浓度。记录术前、冠脉结扎后即刻/细胞移植即刻、术后4周的心电图变化。检测术后4周的超声和血流动力学指标变化。结果:80只大鼠均进入结果分析。①骨髓基质干细胞的诱导分化及其植入后的生存状态:5-氮胞苷诱导3周后,骨髓基质干细胞表达肌钙蛋白Ⅰ和肌凝蛋白重链,细胞内有丰富的肌丝和Z线,细胞器较多。植入4周后在心肌瘢痕组织中分化为心肌细胞。②细胞内钙离子浓度:两组细胞在caffeine刺激下钙离子的释放均呈波峰状,但诱导组应用caffeine后钙离子浓度降低且低于基础状态,钙释放受到抑制,未诱导组不受影响。③心电图观察:与术前比较,梗死移植组QRS波变窄,R波降支出现正常顿挫波,未见显著心律失常。④超声检测及血流动力学分析:术后4周,与梗死非移植组比较,梗死移植组左室收缩末压、左室射血分数和压力变化速率最大值均显著升高(P<0.05或0.01)。结论:骨髓基质干细胞体外诱导后能分化为心肌样细胞,植入到瘢痕心肌组织中生存、增殖良好,可改善心电图及心肌弹性,从而改善心肌梗死大鼠的心功能。     

Cardiorespiratory function in asymptomatic survivors of neonatal respiratory distress syndrome

We measured cardiopulmonary function at rest and during exercise in 15 healthy survivors of neonatal respiratory distress syndrome (RDS) and compared the results with those in 15 normal subjects. The mean birth weight of the RDS group was 1,771 g, and 12 of the 15 patients had required endotracheal intubation. The oxygen scores ranged from 79 to 3,322. Five of the 15 RDS patients had abnormal results of pulmonary function studies at rest. Peak expiratory flow was lower (P less than 0.05) in the RDS group (2.98 liters/min) than in the control group (3.57 liters/min). A negative correlation was noted between the forced expiratory flow between 25 and 75% of vital capacity and the oxygen score in these patients. Exercise tolerance was below normal in two of the RDS patients, both of whom also had abnormal pulmonary function at rest. One patient in the RDS group had systemic arterial hypertension at rest and during exercise. No significant differences in exercise tolerance or the cardiorespiratory response to exercise were observed between the two groups.     

Annexin V for flow cytometric detection of phosphatidylserine expression on B cells undergoing apoptosis

Apoptosis, or programmed cell death, is a general mechanism for removal of unwanted cells from the immune system. It is characterized by chromatin condensation, a reduction in cell volume, and endonuclease cleavage of DNA into oligonucleosomal length fragments. Apoptosis is also accompanied by a loss of membrane phospholipid asymmetry, resulting in the exposure of phosphatidylserine at the surface of the cell. Expression of phosphatidylserine at the cell surface plays an important role in the recognition and removal of apoptotic cells by macrophages. Here we describe a new method for the detection of apoptotic cells by flow cytometry, using the binding of fluorescein isothiocyanate-labeled annexin V to phosphatidylserine. When Burkitt lymphoma cell lines and freshly isolated germinal center B cells are cultured under apoptosis inducing conditions, all cells showing chromatin condensation strongly stain with annexin V, whereas normal cells are annexin V negative. Moreover, DNA fragmentation is only found in the annexin V-positive cells. The nonvital dye ethidium bromide was found to stain a subpopulation of the annexin V-positive apoptotic cells, increasing with time. Our results indicate that the phase in apoptosis that is characterized by chromatin condensation coincides with phosphatidylserine exposure. Importantly, it precedes membrane damage that might lead to release from the cells of enzymes that are harmful to the surrounding tissues. Annexin V may prove important in further unravelling the regulation of apoptosis.     

骨髓干细胞移植对心肌梗死大鼠血流动力学指标和心脏功能的影响

目的:心肌梗死所致的细胞缺失和瘢痕形成是心力衰竭乃至死亡的病理基础,目前药物治疗、介入治疗和外科手术均不能替代坏死心肌和彻底改善心脏功能。观察骨髓干细胞移植对心肌梗死大鼠血流动力学指标和心功能的影响。方法:实验于2005-03/2006-10在哈尔滨医科大学附属第一医院细胞移植中心完成。①实验动物:SD雄性大鼠60只作为细胞移植的受体,随机数字表法分成假手术组、心肌梗死组、细胞移植组,20只/组。另取SD雄性幼鼠10只作为骨髓干细胞的供体。实验过程中对动物的处置符合动物伦理学标准。②实验方法:取幼鼠股骨骨髓,Percoll分离后收取细胞层,加入含体积分数为0.1的胎牛血清、100IU/mL青霉素、100g/mL链霉素的DMEM营养液,差速贴壁法分离骨髓干细胞,达80%～90%融合时采用胰酶 乙二胺四乙酸消化传代。向含有第3代骨髓干细胞的培养液中加入5-氮杂胞嘧啶核苷进行诱导,3周后行BrdU标记,离心后配制成1×1012L-1的细胞悬液用于移植。心肌梗死组、细胞移植组大鼠建立心肌梗死模型,假手术组未结扎冠状动脉。细胞移植组吸取0.2mL骨髓干细胞悬液注射到瘢痕组织中,心肌梗死组注入等量干细胞培养液基质,假手术组不予任何移植处理。③实验评估:术后4周,利用导管和心动超声技术检测各组大鼠左室舒张末期内压、左室收缩末期内压、左室压力最大变化值、左室压力最小变化值、等容时间常数和心率。结果:术后4周,与假手术组比较,心肌梗死组左室收缩末期内压、左室压力最大变化值、左室压力最小变化值均明显降低(P<0.01),左室舒张末期内压、等容时间常数均明显增高(P<0.01);与心肌梗死组比较,细胞移植组以上各项指标均明显好转(P<0.01)。结论:骨髓干细胞移植到瘢痕心肌组织中,能改善心肌梗死后大鼠的血流动力学参数和心脏功能。     

Towards peakless, reproducible and long-acting insulins. An assessment of the basal analogues based on isoglycaemic clamp studies

While the advantages of the two basal insulin analogues, glargine and detemir, over neutral protamine Hagedorn are well established, the relative merit of the two compared with each other has been a matter of some controversy. The two analogues are popularly perceived to differ from each other in their pharmacodynamic (PD) profiles, in particular with regard to 'flatness' and duration of action. The aim of this review, therefore, is to give a complete overview on the available PD data of both analogues as derived with the glucose clamp technique. In order to improve parity across studies, a common definition for duration of action (time from injection to plasma glucose >8.3 mmol/l) was applied and study data were recalculated when necessary. Despite differences in methodological details, the results of most clamp studies were very consistent. Glargine and detemir both typically show a gentle rise and fall in glucose-lowering action over time. Duration of action with both analogues is dose dependent, but in the clinically relevant range of 0.35-0.8 U/kg it is close to 24 h in people with type 1 diabetes and in excess of this in people with type 2 diabetes. While both analogues seem to be very similar with regard to the mean shape of their PD profile and duration of action, detemir shows less within-subject variability in its metabolic effect. These findings in experimental glucose clamp studies are consistent with observations in clinical trials and support routine once daily use with either analogue, in particular in people with type 2 diabetes.     

Extracolonic Tumors of the Gastrointestinal Tract Detected Incidentally at Screening CT Colonography

Purpose The aim of this article is to report our experience with incidental detection of extracolonic tumors of the gastrointestinal tract identified prospectively at screening CT colonography. Methods A total of 2014 patients (1097 females, 917 males; mean age, 56.9 years) underwent primary CT colonography evaluation at our institution over an 18-month period. Following cathartic preparation and colonic distention, supine and prone multidetector CT scans were obtained with thin-collimation low-dose technique without intravenous contrast. We reviewed our database for lesions of the extracolonic gastrointestinal tract that were detected during the prospective reading. Results Focal extracolonic gastrointestinal tract lesions were prospectively detected in 10 (0.5 percent) of 2014 patients (8 females; 2 males; mean age, 58.5 years). All patients were asymptomatic. Tumor locations included ileum (n = 3), stomach (n = 3), jejunum (n = 2), and appendix (n = 2). Mean tumor size was 2.2 (range, 0.8–3.4) cm. Lesions in eight patients were subsequently confirmed by conventional or capsule endoscopy and/or by intravenous contrast-enhanced CT. Seven lesions were surgically excised and one was removed at endoscopy; two patients with lipomas did not undergo further evaluation or treatment. Final diagnoses were benign in all cases and included lipoma (n = 3), small-bowel hamartoma (n = 2), appendiceal mucinous cystadenoma (n = 2), gastric leiomyoma (n = 1), small-bowel lymphangioma (n = 1), and gastric fundic gland polyp (n = 1). Conclusions Incidental extracolonic tumors of the gastrointestinal tract detected at screening CT colonography were all asymptomatic and benign but often prompted more invasive workup. Although the incidence of these tumors was relatively low, widespread population screening with CT colonography would result in new surgical referrals for these findings.     

Lehre und Simulation

Since 1st October 2003 the new German "Approbationsordnung für Arzte" (Medical Licensing Regulations) requires an increasing amount of small group teaching sessions and encourages a multidisciplinary and more practical approach to the related topics. In 2004 the German Society of Anaesthesiology and Intensive Care Medicine has provided almost all anaesthesia faculties of German Universities with equipment for full-scale simulation. This article describes methods for a simulation-based medical education training program. Basic requirements for a successful training program using full scale simulators are the provision of an adequate logistical and material infrastructure, teacher attendance of train-the-trainer courses, implementation in the medical curriculum and an instructor-student ratio of 1:3, equivalent to that for bedside teaching. If these requirements were fulfilled, medical students scored the simulation scenarios "induction of anaesthesia", "acute pulmonary embolism", "acute management of a multiple trauma patient" and "postoperative hypotension" as 1.5, 1.6, 1.5 and 1.5, respectively, on a scale of 1-6. These scores were better than those given for other segments of the curriculum.