超声介导载紫杉醇微泡对小鼠H22皮下移植瘤抑制作用的实验研究

目的探讨超声介导自制载紫杉醇微泡对小鼠H22皮下移植瘤的抑制效果。方法 (1)自制载紫杉醇微泡,并检测其一般特性。(2)建立小鼠H22皮下移植瘤模型,给予紫杉醇微泡+超声处理。绘制肿瘤生长曲线,计算各组抑瘤率,肿瘤行病理组织学检查,免疫组织化学法检测微血管密度(MVD),Western Blotting检测Bax、Bcl-2蛋白的表达。结果 (1)微泡呈圆形,表面光滑,平均粒径2.07μm,载药量10.13%,包封率89.58%。(2)紫杉醇微泡+超声组肿瘤生长明显减慢,肿瘤体积和质量明显下降(P0.05),肿瘤组织HE染色呈现不同程度变性坏死,MVD表达减少,Bax的表达上调,Bcl-2的表达下调(P0.05)。结论超声介导载紫杉醇微泡可明显抑制小鼠H22皮下移植瘤的生长,并可降低肿瘤组织MVD的表达,促进肿瘤细胞的凋亡。     

超声靶向微泡破坏技术协同二氢卟吩e6介导声动力治疗小鼠肝癌移植瘤

目的探讨载二氢卟吩e6纳米脂质微泡介导的超声靶向微泡破坏技术及声动力治疗对肝癌移植瘤的协同抑制作用。方法制备Ce6-MB并检测其形态、粒径及包封率。将H22肝癌皮下移植瘤小鼠随机分为对照组、Empty-MB组、Ce6组、Ce6-MB组。治疗5次后计算抑瘤率,冰冻切片观察Ce6肿瘤聚集情况,HE、TUNEL染色观察细胞及组织凋亡情况,RT-qPCR及免疫组化法检测Bcl-2、Bax的基因及蛋白表达。结果 Ce6-MB为分散均匀纳米级球形微泡,包封率为40.85%±3.09%,Ce6-MB组比Ce6组肿瘤聚集更多Ce6。与对照组相比,Empty-MB、Ce6、Ce6-MB组均可抑制肿瘤生长,Bax mRNA和蛋白高表达,Bcl-2低表达,以上结果以Ce6-MB组为显著(P0.01)。结论成功制备载Ce6纳米脂质微泡,超声靶向微泡破坏技术协同Ce6介导的声动力疗法可有效治疗小鼠肝癌移植瘤。     

超声介导载sPD-1和miR-206基因纳米微泡协同抑制小鼠H22肝癌皮下移植瘤

目的 探讨超声介导载可溶性程序性死亡因子1（sPD-1）联合miR-206纳米微泡对小鼠H22肝癌皮下移植瘤的干预效果。方法 自制载sPD-1和miR-206基因的纳米微泡,构建H22肝细胞癌皮下移植瘤小鼠模型,并将模型小鼠随机分为模型组、空微泡组、miR-206微泡组、sPD-1微泡组、联合组（给予miR-206微泡组及sPD-1微泡）,分别每2天经尾静脉给予生理盐水及相应的微泡,每次注射后给予超声辐照瘤体治疗1次。5次治疗后取小鼠肿瘤组织,测量肿瘤质量及体积,计算肿瘤体积及质量抑瘤率,HE染色观察肿瘤组织病理变化,免疫组织化学法检测小鼠肿瘤组织Bax、Bcl-2蛋白表达,半定量PCR检测Bax、Bcl-2、c-met、γ干扰素（IFN-γ）、程序性死亡因子-1配体（PD-L1）mRNA表达,实时荧光定量PCR检测miR-206表达。结果 制备的纳米微泡呈球形,分布均一。与模型组比较,各组肿瘤体积、肿瘤质量均降低,体积抑瘤率及质量抑瘤率均升高（P均<0.05）;上述变化以联合组为著（P均<0.05）。与模型组比较,其余各组Bax蛋白和mRNA均高表达、Bcl-2蛋白和mRNA均低表达,以联合组为著（P均<0.01）。各组小鼠肿瘤组织Bax、Bcl-2、c-met、PD-L1、IFN-γ、miR-206 mRNA表达差异均有统计学意义（P均<0.01）。结论 超声介导载sPD-1和miR-206纳米微泡可协同抑制小鼠H22肝癌皮下移植瘤生长。     

超声微泡介导miR-34a联合DOX治疗小鼠U14皮下移植瘤的实验研究

目的研究超声介导载miR-34a、DOX微泡对小鼠U14宫颈癌皮下移植瘤联合治疗效果。方法制备载miR-34a、DOX高分子微泡,检测一般性质;建立小鼠皮下移植瘤模型,随机分为:模型组、空微泡组、DOX微泡组、miR-34a微泡组、miR-34a联合DOX微泡组;超声微泡治疗小鼠皮下移植瘤,绘制肿瘤生长曲线图,计算抑瘤率;RT-PCR检测各组小鼠肿瘤组织miR-34a基因表达情况;免疫组织化学染色法检测肿瘤微血管密度(MVD)和凋亡蛋白Bcl-2、Bax表达情况。结果自制高分子微泡呈球形,分布均一,平均粒径1.87μm,包封率为46.24%,载药量为10.58%;与模型组相比,各治疗组肿瘤生长减慢,肿瘤质量体积显著下降,联合治疗效果更佳并与单一作用比较具有显著差异(P0.05);聚合酶链式反应(RT-PCR)结果显示,miR-34a组和联合组肿瘤组织中miR-34a高表达;DOX组、miR-34a组和联合组免疫组织化学染色检测肿瘤微血管密度(MVD)降低,凋亡蛋白Bcl-2表达下调,Bax高表达,联合组更加明显(P0.05)。结论超声微泡介导的miR-34a和DOX的共同递送可以实现肿瘤抑制的协同效应。     

超声纳米微泡增强阿霉素对小鼠H22移植瘤抑制作用的实验

目的探讨超声辐照联合纳米微泡是否能增强阿霉素对小鼠H22移植瘤的抑制作用。方法将50只已建立皮下H22移植瘤模型的昆明雌鼠随机分为五组,即对照组、单纯阿霉素组(ADM)、阿霉素+纳米微泡组(ADM+NMB)、阿霉素+超声组(ADM+US)、阿霉素+纳米微泡+超声组(ADM+NMB+US),每组10只,隔天治疗1次,监测皮下肿瘤的生长情况,治疗5次,观察肿瘤细胞坏死情况,计数肿瘤组织微血管密度,并观察小鼠生存期,评价各种处理对肿瘤的抑制作用。结果相对于对照组,治疗组肿瘤生长延缓,小鼠寿命延长,肿瘤坏死面积增加,微血管密度减少(P0.05),而ADM+NMB+US组与其他治疗组相比,差异更显著(P0.05)。结论超声联合纳米微泡可增强阿霉素对小鼠H22移植瘤的抑制作用。     

载血卟啉PLGA微泡用于声动力治疗小鼠H22肝癌移植瘤

目的 研究超声联合载血卟啉PLGA造影剂对小鼠H22肝癌皮下移植瘤的声动力治疗作用. 方法 自制载血卟啉高分子材料PLGA造影剂并检测其基本特性.选择30只荷H22肝癌皮下移植瘤小鼠,随机平均分为5组进行治疗,绘制治疗后15天内肿瘤体积生长曲线,比较其质量抑瘤率,并采用TUNEL和PCNA检测各组小鼠肿瘤细胞凋亡情况及增殖活性. 结果 自制的载血卟啉PLGA微泡造影剂平均粒径为602.3 nm,分布均匀,包封率63.50%,载药量2.15%.治疗后,与其他各组比较,超声加载药微泡治疗组肿瘤生长曲线最平缓,质量抑瘤率及凋亡指数均显著高于其他4组(P＜0.05),而增殖指数明显低于其他各组(P＜0.05). 结论 超声联合载血卟啉高分子纳米造影剂能够抑制小鼠H22肝癌移植瘤生长,促进其凋亡.     

靶向PD-L1纳米微泡的制备及其对肝癌移植瘤抑制作用的实验研究

目的探讨靶向PD-L1纳米微泡(PD-L1-NB)的靶向性及其对肝癌移植瘤抑制作用。方法制备PD-L1-NB并检测其一般特性和靶向性。构建小鼠H22细胞肝癌皮下移植瘤模型,分为模型组、非靶向微泡(N-NB)组、PD-L1-NB组,每隔一天经小鼠尾静脉注射200μL不同药物,于每次注射结束后立即超声辐照瘤体,于每次治疗前称量小鼠体质量,测量小鼠瘤体大小,绘制小鼠肿瘤生长曲线,进行肿瘤组织形态学观察,免疫荧光检测PD-L1蛋白的表达,乳酸脱氢酶法检测脾淋巴细胞增殖情况,RT-PCR检测INF-γ、IL-2、Bax、Bcl-2等免疫、凋亡指标。结果制备出的PD-L1-NB呈球形,为纳米级别,大小形态均一,具有良好的靶向性。与模型组比,N-NB组和PD-L1-NB组均能抑制肿瘤生长,且PD-L1-NB组肿瘤生长最为缓慢(P0.05);N-NB组和PD-L1-NB组肿瘤组织中均有不同程度的变性坏死,PD-L1-NB组较N-NB组更明显;PD-L1-NB组中PD-L1表达明显下调(P0.001),淋巴细胞的杀伤作用最明显(P0.001);各组INF-γ、IL-2、Bax、Bcl-2 mRNA表达均有统计学意义。结论成功制备靶向PD-L1纳米微泡并显著抑制肝癌移植瘤的生长。     

超声辐照载羟基喜树碱微泡对肝癌SMMC-7721 细胞凋亡及相关蛋白表达的影响

目的 研究超声辐照载羟基喜树碱微泡对肝癌SMMC-7721细胞凋亡的影响,并探讨其诱导细胞凋亡的分子机制.方法 SMMC-7721细胞随机分为6组,即对照组、空白脂质微泡+超声组、载羟基喜树碱微泡组、羟基喜树碱组、羟基喜树碱+超声组及载羟基喜树碱微泡+超声组.采用Annexin V-FITC/PI双染法和TUNEL法检测细胞凋亡状况;免疫细胞化学法检测Bel-2、Bax蛋白表达.结果 载羟基喜树碱微泡+超声组用Annexin V-FITC/PI检测细胞早期凋亡率为(12.18±1.38)%;TUNEL法显示染成棕黄色的凋亡细胞,细胞中晚期凋亡率为(34.25±1.83)%;免疫细胞化学法检测Bcl-2蛋白表达下降,Bax蛋白表达升高,Bel-2/Bax比值明显下降.以上结果与其他组的检测结果相比,差异具有统计学意义.结论 超声辐照载羟基喜树碱微泡能明显诱导肝癌SMMC-7721细胞凋亡,其机制可能与降低Bcl-2/Bax比值有关.     

超声靶向辐照载药微泡治疗小鼠H22肝癌的实验研究

目的 制备载10-羟基喜树碱(10-HCPT)脂质超声微泡(10-hydroxycamptothecine-loaded liposome microbubbles,HLM),并研究超声定位辐照载药微泡对H22移植瘤的生长抑制效应.方法 制备载10-HCPT的脂质微泡及空白脂质微泡,建立小鼠肝癌H22实体瘤模型,将荷瘤鼠随机分为A、B两大组,每组又分为HLM组、10-HCPT注射液组、空白脂质微泡组和生理盐水对照组,经小鼠尾静脉输入药物或微泡后立即以治疗超声辐照瘤体部位,连续治疗7 d.A组小鼠治疗结束后剥取瘤块称重.计算抑瘤率,并作病理切片分析肿瘤微血管密度(MVD)变化;从治疗当天起,描绘B组小鼠肿瘤生长曲线,并观察生存期.结果 HLM组抑瘤率明显高于其他各组,MVD较其他组低(P<0.05),该组小鼠生存天数较对照组明显延长(P<0.01),但与10-HCPT注射液组比较差异无统计学意义(P>0.05);空白微泡组各检测指标与对照组差异无统计学意义(P>0.05).结论 超声靶向破坏载药微泡可显著提高10-HCPT对H22移植瘤的生长抑制效应,并可增强10-HCPT对肿瘤血管生成的抑制作用,有望成为一种新的靶向抗肿瘤治疗手段.     

超声靶向辐照载药微泡治疗小鼠H22肝癌的实验研究

目的 制备载10-羟基喜树碱(10-HCPT)脂质超声微泡(10-hydroxycamptothecine-loaded liposome microbubbles,HLM),并研究超声定位辐照载药微泡对H22移植瘤的生长抑制效应.方法 制备载10-HCPT的脂质微泡及空白脂质微泡,建立小鼠肝癌H22实体瘤模型,将荷瘤鼠随机分为A、B两大组,每组又分为HLM组、10-HCPT注射液组、空白脂质微泡组和生理盐水对照组,经小鼠尾静脉输入药物或微泡后立即以治疗超声辐照瘤体部位,连续治疗7 d.A组小鼠治疗结束后剥取瘤块称重.计算抑瘤率,并作病理切片分析肿瘤微血管密度(MVD)变化;从治疗当天起,描绘B组小鼠肿瘤生长曲线,并观察生存期.结果 HLM组抑瘤率明显高于其他各组,MVD较其他组低(P<0.05),该组小鼠生存天数较对照组明显延长(P<0.01),但与10-HCPT注射液组比较差异无统计学意义(P>0.05);空白微泡组各检测指标与对照组差异无统计学意义(P>0.05).结论 超声靶向破坏载药微泡可显著提高10-HCPT对H22移植瘤的生长抑制效应,并可增强10-HCPT对肿瘤血管生成的抑制作用,有望成为一种新的靶向抗肿瘤治疗手段.     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

Clinical Pharmacokinetics of Morphine

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.     

手转胎头术失败的原因与分娩结局临床分析

目的 探讨手转胎头术失败的原因与分娩结局.方法 选择2008年1月至2010年12月于我院住院分娩的持续性枕横位、枕后位产妇198例,根据行手转胎头术后结果分为成功组126例、失败组72例.比较两组分娩结局,对比分析失败原因.结果 失败组胎儿体质量≥3500 g的发生率[76.4％(55/72)]明显高于成功组[31.7％(40/126)],差异有统计学意义(x2=30.177,P=0.001)、失败组宫缩乏力发生率[58.3％(42/72)]高于成功组[38.1％ (48/126)],差异有统计学意义(x2=7.569,P=0.006)、失败组骨盆临界或轻度狭窄发生率[38.9％ (28/72)]高于成功组[23.8％(30/126)],差异有统计学意义(x2 =5.030,P=0.002)、失败组手转胎头时机不当(宫口开大＜6 cm、胎头位于坐骨棘上及宫口开大8～10 cm、胎头位于坐骨棘下≥2 cm)发生率[61.1％(44/72)]高于成功组[38.9％(49/126)],差异有统计学意义(x2=9.084,P=0.003).失败组母儿并发症(产后出血、产褥病率、胎儿窘迫、新生儿窒息)发生率高于成功组(x2 =9.586,P=0.002、x2=9.334,P=0.002、x2=5.910,P=0.015、x2=5.240,P=0.022)、失败组剖宫产发生率[72.2％(52/72)]明显高于成功组[34.1 ％(43/126),x2=26.641,P=0.001)].结论 手转胎头术能使难产变顺产,降低剖宫产率,减少母儿并发症,但须积极预防、处理导致手转胎头术失败的原因,对矫正失败后继续矫正及试产应慎重.     

Evidence-Based Pain Management and Palliative Care in Issue Four for 2009 of The Cochrane Library

ABSTRACT

The Cochrane Library of Systematic Reviews is published quarterly. Issue 4 for 2009 contains 4027 complete reviews, 1906 protocols for reviews in production, and 11447 one-page summaries of systematic reviews published in the general medical literature. In addition, there are citations of 600,000 randomized controlled trials, and 12,200 cited papers in the Cochrane methodology register. The health technology assessment database contains over 7500 citations. This edition of the Library contains 90 new reviews, of which 19 have potential relevance for practitioners in pain and palliative medicine.     

Wie zuverlässig sind Angaben zu nichtentzündlichen ausgedehnten Schmerzen?

ZusammenfassungFragestellung Es wurde geprüft, wie sich der Differenziertheitsgrad zweier Schmerzmessmethoden auf Angaben zur Ausgedehntheit klinischer Schmerzen auswirkt. Zugleich wurde der Referenzzeitraum variiert, über den die Patienten berichten sollten.Methode Erfasst wurde der Einfluss zu Lasten der Befragungsdifferenziertheit durch den Vergleich zweier Körperschema-Bildvorlagen. Drei Referenzzeiträume (Schmerz aktuell, letzte Woche, letztes halbes Jahr) wurden vorgegeben.Ergebnisse Patienten mit ausgedehnten Schmerzen gaben bei differenzierter Befragung um so mehr Schmerzen an, je weiter die Schmerzen zurück lagen und je größer der Berichtszeitraum war. Patienten mit gelenknahen Schmerzen gaben bei hoch differenzierter Befragung weniger ausgedehnte Schmerzen in der Vergangenheit an als bei globaler Einschätzung. Patienten mit Rückenschmerzen berichteten bei differenzierter Befragung zum aktuellen Schmerz über weniger ausgedehnte Schmerzen als bei globaler Befragung.Schlussfolgerung Die Angaben zur Schmerzausdehnung variieren vor allem bei Patienten mit ausgedehnten Schmerzen in Abhängigkeit von der Differenziertheit der Befragung. In diesen Fällen ist die Wahrscheinlichkeit erhöht, dass sich die Beschwerdesymptomatik zumindest teilweise erst in der Reaktion auf die situativen Befragungsbedingungen konstituiert und daher nicht auf andere Befragungsbedingungen generalisiert werden kann.