Interleukin-2 activated NK cells do not use the CD95L- and TRAIL-pathways in the rapid induction of apoptosis of rat colon carcinoma CC531s cells

Natural Killer (NK) cells can induce apoptosis in target cells in at least four ways: by secretion of granzyme B/perforin (GrB/P) and via the CD95L, TRAIL and TNF-α pathways. In this study we examined the pathways used by interleukin-2 activated rat NK (A-NK) cells to induce apoptosis in the rat colon carcinoma cell line CC531s. Co-incubation of A-NK cells with CC531s cells for three hours resulted in 70% apoptosis in the latter. Addition of the GrB/P pathway-inhibitor concanamycin A reduced the number of apoptotic cells to 54%. Blockade of the CD95L, TRAIL and TNF-α pathways by specific antibodies hardly had an additional effect. However, co-incubation with transfected MEC cells that expressed CD95L or 2PK3-cells that expressed TRAIL did induce apoptosis in CC531s cells. Furthermore the A-NK cells contained CD95L and TRAIL. However, comparison of non- and permeabilized cells revealed that the majority of TRAIL was present in the cytosol of A-NK cells and was not available for induction of apoptosis. The presence of elevated levels of bcl-2 in CC531 cells reduced the sensitivity towards induction of apoptosis both by A-NK cells as well as the CD95L and TRAIL expressing cell lines. Using the caspase-inhibitors ac-IEPD-CHO, ac-DEVD-CHO and zVAD-fmk, it was shown that inhibition of the effector caspase-3 prevented A-NK cell induced apoptosis in CC531-bcl-2 cells, but not in CC531s cells. In conclusion, A-NK cells kill by secretion of GrB/P and not by the CD95L, TRAIL or TNF pathways albeit both CD95L and TRAIL are produced by the A-NK cells.     

Secondary and tertiary structure modeling reveals effects of novel mutations in polycystic liver disease genes PRKCSH and SEC63

Waanders E, Venselaar H, te Morsche RHM, de Koning DB, Kamath PS, Torres VE, Somlo S, Drenth JPH. Secondary and tertiary structure modeling reveals effects of novel mutations in polycystic liver disease genes PRKCSH and SEC63. Polycystic liver disease (PCLD) is characterized by intralobular bile duct cysts in the liver. It is caused by mutations in PRKCSH, encoding hepatocystin, and SEC63, encoding Sec63p. The main goals of this study were to screen for novel mutations and to analyze mutations for effects on protein structure and function. We screened 464 subjects including 76 probands by direct sequencing or conformation‐sensitive capillary electrophoresis. We analyzed the effects of all known and novel mutations using a combination of splice site recognition, evolutionary conservation, secondary and tertiary structure predictions, Poly Phen , and p Mut and sift . We identified a total of 26 novel mutations in PRKCSH (n = 14) and SEC63 (n = 12), including four splice site mutations, eight insertions/ deletions, six non‐sense mutations, and eight missense mutations. Out of 48 PCLD mutations, 13 were predicted to affect splicing. Most mutations were located in highly conserved regions and homology modeling for two domains of Sec63p showed severe effects of the residue substitutions. In conclusion, we identified 26 novel mutations associated with PCLD and we provide in silico analysis in order to delineate the role of these mutations.     

伤椎置钉法在胸腰椎骨折治疗中的应用价值

目的探讨伤椎置钉法对胸腰椎骨折的复位与固定效果。方法对38例胸腰椎骨折椎双侧或一侧椎弓根完整、椎体下半部及下终板无爆裂患者,通过伤椎植入椎弓根螺钉,在后路行椎间撑开、连接钉棒使伤椎复位的过程中,使伤椎获得垂直向前的推顶力,以期恢复伤椎前柱高度和后凸Cobb角的矫正,达到局部的应力平衡。所有患者外伤至手术时间为1～10d,平均5.1d。结果术后随访6～40个月,平均18个月。后凸Cobb角由术前平均25.4°恢复至术后平均2.3°;椎体前缘由术前正常椎体平均高度的58.8%矫正至术后正常椎体平均高度的90.3%;伤椎脱位均基本复位,无椎间隙过度撑开、内固定物松动断裂现象;33例合并圆锥、马尾神经损伤的病例,术后神经功能按Frankel分级比较,31例(93.9%)有1～3级的改善。6例术后15～18个月行内固定物取出术,见后外侧植骨融合良好。结论伤椎置钉法是安全的,可有效地使伤椎获得良好复位与固定,有利于维持矫正效果、减少内固定的松动或断裂。     

Descriptive epidemiology of thyroid cancer in the Swiss Canton of Vaud

Although substantial decreases have been recorded, age-standardized mortality rates from thyroid cancer in Switzerland are still the highest in Europe in men (0.9/100,000), together with those from Austria, and the third highest (1.0/100,000) in women. Detailed analysis of 308 new cases registered between 1974 and 1987 in the Swiss Canton of Vaud revealed an overall incidence rate of 1.36/100,000 men (world standard) in 1974-1980 and of 1.74/100,000 in 1981-1987. Corresponding values for women were 4.28 and 4.51, respectively. Thus, women constituted the majority of all cases (76%). Papillary carcinoma was the most frequent histological type (53%) followed by follicular (27%), undifferentiated (5%) and medullary (2%); other morphologies and clinical tumours accounted for 13% of the whole series. In both sexes, most of the apparent increase over the calendar period was restricted to the papillary type. Overall 5- and 10-year survival rates were 71% and 57%. When various factors were introduced in a Cox proportional-hazard model, young age at diagnosis (hazard rate for greater than or equal to 65 years vs less than 45 = 14.7; 95% confidence interval = 7.5-29.1) and good histological differentiation (hazard rate for papillary and follicular vs undifferentiated = 0.4) emerged as strong favourable and independent prognostic factors. The reduced hazard rate for women, other factors being equal, was of borderline significance (0.7, 95% confidence interval = 0.5-1.0), whereas no significant difference was observed between follicular and papillary carcinomas, and calendar periods of diagnosis.     

Validity of a modified Demirjian system based on an Australian dataset – simple maturity score in age estimation

This pilot study is a validation of a modified Demirjian’s System developed for the Australian population by Blenkin and Evans. The study sample comprised orthopantomographs of 230 individuals aged 2.5 to 14.5 years. Seven right mandibular teeth (excluding the wisdom tooth) were assessed and graded according to the Demirjian’s stages of tooth development. Corresponding modified numeric scores for the stages were summed to form a simple maturity score from which age estimates were derived. The mean difference between the estimated and chronological age for girls was 0.02 years, 95% CI [-0.13, 0.17]. Paired-sample t-test results found this difference not to be statistically significant p = 0.81, <0.05. For boys, the method underestimated the age with a mean difference of –0.24 years 95% CI [–0.4, –0.08]. Paired t-test found this to be significantly different (p = 0.003). This study found that the modified Demirjian’s System of Blenkin and Evans is valid for use in the Australian population.     

CTA显示胃周动脉及其变异在胃癌术前评价中的应用价值

目的探讨CT血管造影(CT angiography,CTA)显示胃周动脉及其变异在胃癌术前评估中的应用价值。资料与方法对连续67例经胃镜活检证实或高度怀疑胃癌的患者,采用多层螺旋CT在患者服用产气粉和水(500～1000 ml)充分扩张胃后经静脉用压力注射器以3～4 ml/s的流率团注碘对比剂100 ml(碘必乐或碘普罗胺370),采用Bolus-Tracking追踪触发技术行三期增强扫描。在CT工作站采用容积再现(VR)和最大密度投影(MIP)重组CTA以显示胃周血管影像,重点分析变异动脉对手术方案的抉择与实施的影响,并与手术发现比较。结果 67例胃左动脉(LGA)均被显示,胃右动脉(RGA)的显示率为52.24%(35/67)。CTA显示12例胃周动脉变异。其中61例实施手术治疗,CTA获得的血管解剖信息与手术所见取得较好的一致性。结论 CTA能显示胃周主要动脉及其解剖变异,特别是与胃癌原发灶解剖密切相关并对手术实施有影响的血管,附加的CTA可以提高胃癌CT检查的成本效益比。     

Overexpression of α‐synuclein in an astrocyte cell line promotes autophagy inhibition and apoptosis

α‐Synuclein is the major component of neuronal cytoplasmic aggregates called Lewy bodies, the main pathological hallmark of Parkinson disease. Although neurons are the predominant cells expressing α‐synuclein in the brain, recent studies have demonstrated that primary astrocytes in culture also express α‐synuclein and regulate α‐synuclein trafficking. Astrocytes have a neuroprotective role in several detrimental brain conditions; we therefore analyzed the effects of the overexpression of wild‐type α‐synuclein and its A30P and A53T mutants on autophagy and apoptosis. We observed that in immortalized astrocyte cell lines, overexpression of α‐synuclein proteins promotes the decrease of LC3‐II and the increase of p62 protein levels, suggesting the inhibition of autophagy. When these cells were treated with rotenone, there was a loss of mitochondrial membrane potential, especially in cells expressing mutant α‐synuclein. The level of this decrease was related to the toxicity of the mutants because they show a more intense and sustained effect. The decrease in autophagy and the mitochondrial changes in conjunction with parkin expression levels may sensitize astrocytes to apoptosis.     

The mismatch repair system protects against intergenerational GAA repeat instability in a Friedreich ataxia mouse model

Friedreich ataxia (FRDA) is an autosomal recessive neurodegenerative disorder caused by a dynamic GAA repeat expansion mutation within intron 1 of the FXN gene. Studies of mouse models for other trinucleotide repeat (TNR) disorders have revealed an important role of mismatch repair (MMR) proteins in TNR instability. To explore the potential role of MMR proteins on intergenerational GAA repeat instability in FRDA, we have analyzed the transmission of unstable GAA repeat expansions from FXN transgenic mice which have been crossed with mice that are deficient for Msh2, Msh3, Msh6 or Pms2. We find in all cases that absence of parental MMR protein not only maintains transmission of GAA expansions and contractions, but also increases GAA repeat mutability (expansions and/or contractions) in the offspring. This indicates that Msh2, Msh3, Msh6 and Pms2 proteins are not the cause of intergenerational GAA expansions or contractions, but act in their canonical MMR capacity to protect against GAA repeat instability. We further identified differential modes of action for the four MMR proteins. Thus, Msh2 and Msh3 protect against GAA repeat contractions, while Msh6 protects against both GAA repeat expansions and contractions, and Pms2 protects against GAA repeat expansions and also promotes contractions. Furthermore, we detected enhanced occupancy of Msh2 and Msh3 proteins downstream of the FXN expanded GAA repeat, suggesting a model in which Msh2/3 dimers are recruited to this region to repair mismatches that would otherwise produce intergenerational GAA contractions. These findings reveal substantial differences in the intergenerational dynamics of expanded GAA repeat sequences compared with expanded CAG/CTG repeats, where Msh2 and Msh3 are thought to actively promote repeat expansions.