5-氮杂-2'-脱氧胞苷和曲古霉素A联合应用对胶质瘤细胞增殖和侵袭的作用

目的胶质瘤的化疗一直都是研究热点,近来有研究表明甲基化与胶质瘤的发生和发展关系密切,本研究的目的是探讨去甲基化试剂5-氮杂-2'-脱氧胞苷(5-Aza-2'-deoxycytidine)和曲古霉素A(TSA)联合应用对胶质瘤细胞系侵袭和转移的调节。方法分别将浓度为50μM的5-氮杂-2'-脱氧胞苷和300ng/ml的曲古霉素A加入胶质瘤细胞系U251细胞中,并将两者联合应用加入U251细胞系中,应用MTT法检测不同处理组细胞的增殖能力,Transwell细胞侵袭实验检测不同处理组和对照组中细胞的侵袭能力的变化。结果 5-氮杂-2'-脱氧胞苷和曲古霉素A单独处理后,U251细胞的增殖能力明显减弱(<0.05),两者联合应用时对U251细胞的增殖抑制更明显(<0.01)。Transwell细胞侵袭实验显示5-氮杂-2'-脱氧胞苷和曲古霉素A单独处理后,U251细胞的侵袭细胞数明显减少(<0.05),而两者联合应用时对U251细胞的侵袭能力抑制更为明显(P<0.01)。结论 5-氮杂-2'-脱氧胞苷和曲古霉素A都可以抑制胶质瘤细胞系的增殖和侵袭,两者具有协同作用。     

HDAC inhibitors dysregulate neural stem cell activity in the postnatal mouse brain

The mammalian central nervous system (CNS) undergoes significant expansion postnatally, producing astrocytes, oligodendrocytes and inhibitory neurons to modulate the activity of neural circuits. This is coincident in humans with the emergence of pediatric epilepsy, a condition commonly treated with valproate/valproic acid (VPA), a potent inhibitor of histone deacetylases (HDACs). The sequential activity of specific HDACs, however, may be essential for the differentiation of distinct subpopulations of neurons and glia. Here, we show that different subsets of CNS neural stem cells (NSCs) and progenitors switch expression of HDAC1 and HDAC2 as they commit to a neurogenic lineage in the subventricular zone (SVZ) and dentate gyrus (DG). The administration of VPA for only one week from P7–P14, combined with sequential injections of thymidine analogs reveals that VPA stimulates a significant and differential decrease in the production and differentiation of progeny of NSCs in the DG, rostral migratory stream (RMS), and olfactory bulb (OB). Cross-fostering VPA-treated mice revealed, however, that a postnatal failure to thrive induced by VPA treatment had a greater effect on DG neurogenesis than VPA action directly. By one month after VPA, OB interneuron genesis was significantly and differentially reduced in both periglomerular and granule neurons. Using neurosphere assays to test if VPA directly regulates NSC activity, we found that short term treatment with VPA in vivo reduced neurosphere numbers and size, a phenotype that was also obtained in neurospheres from control mice treated with VPA and an alternative HDAC inhibitor, Trichostatin A (TSA) at 0 and 3 days in vitro (DIV). Collectively, these data show that clinically used HDAC inhibitors like VPA and TSA can perturb postnatal neurogenesis; and their use should be carefully considered, especially in individuals whose brains are actively undergoing key postnatal time windows of development.     

人参土芽孢杆菌用于胰酪大豆胨琼脂培养基的质量控制研究

目的：通过考察辅料检出的人参土芽孢杆菌（Bacillus ginsengihumi）在不同胰酪大豆胨琼脂培养基（TSA）的生长情况反映培养基的性能差异,讨论菌株作为TSA培养基适用性试验用菌的可行性。方法：将带菌辅料和经多项鉴定的人参土芽孢杆菌分别接种至8个厂家的TSA培养基和TSA对照培养基,讨论9种TSA培养基对辅料污染微生物的检出能力,以及8家企业TSA培养基对人参土芽孢杆菌的促生长能力。结果：由于该辅料携带微生物对营养要求的特殊性,部分厂家TSA检出能力不足,需氧菌总数检查结果偏低。仅B、E两个厂家培养基的促生长能力较高（均大于70%）,结果与检出能力一致。结论：质控实验室根据实际需要,可将人参土芽孢杆菌作为TSA质量控制菌株之一。通过本文的讨论模式,各质控实验室也可增加生产环境或产品中的分离菌株,以用于培养基的质量评价,确保培养基对样品检测的灵敏度和可信度,使检验方法更加科学,检验结果更加准确。     

组蛋白去乙酰化酶抑制剂诱导HeLa细胞p21WAF1/CIP1表达的分子机制研究

目的：研究组蛋白去乙酰化酶抑制剂（HDIs）诱导肿瘤细胞产生周期阻滞以及诱导p21^WAF1／CIP1表达的分子机制。方法：以人宫颈癌HeLa细胞为模型，用曲古抑茵素A（TSA）处理HeLa细胞，通过流式细胞术检测细胞周期及凋亡，通过Western印迹及RT-PCR检测周期相关分子的蛋白及mRNA的表达；并构建TSA靶分子启动子区的荧光素酶报告质粒，进一步检测TSA的主要作用位点，寻找相关作用途径。结果与结论：TSA可诱导HeLa细胞发生周期阻滞，并呈现明显的剂量和时间依赖关系，加大用药剂量及延长用药时间可诱导凋亡。TSA可显著诱导p21^WAF1／CIP1的表达，表现为转录水平的调节，其变化可以指示周期阻滞的程度。p21^WAF1／CIP1启动子区3′端是TSA作用的主要位点，同样被TSA诱导表达增加的p53很可能通过与其效应元件的结合而使TSA诱导p21^WAF1／CIP1表达的总效果增强。     

Differentiation of sarcoidosis from tuberculosis by use of electron capture gas-liquid chromatography

To explore further the possible etiologic role of mycobacteria in the development of sarcoidosis, we measured free, nonbound tuberculostearic acid (TSA, 10-methyloctadecanoic), a component of mycobacteria, in the sera of subjects with sarcoidosis or active untreated pulmonary tuberculosis and in healthy controls by use of frequency-pulsed electron capture gas-liquid chromatography (FPEC-GLC). The selective analytic system is capable of measuring as little as 15-fmol quantities of free, nonbound TSA in serum and cerebral spinal fluid. We found that TSA was present in the sera of all subjects with Mycobacterium tuberculosis (n = 10) but was undetectable in subjects with sarcoidosis (n = 15) and in healthy controls (n = 15), thereby suggesting that if sarcoidosis is caused by a mycobacterial organism, TSA is not produced or does not gain access to the systemic circulation in quantities sufficient for measurement. However, in the course of the studies we found that a peak, designated p11, was elevated in the sera of all subjects with acute sarcoidosis (n = 4). Also, a peak designated p3 was reduced significantly in all subjects with acute and chronic sarcoidosis and absent in subjects with M. tuberculosis compared with healthy controls. Both peaks were later shown by chemical analysis and mass spectral studies to be carboxylic acids not previously associated with specific disease entities. Follow-up detailed studies will be needed to determine if quantitation of these unique carboxylic acids will be useful in differentiating sarcoidosis from other disorders.     

Marijuana smoking and fungal sensitization

The possible role of marijuana (MJ) in inducing sensitization to Aspergillus organisms was studied in 28 MJ smokers by evaluating their clinical status and immune responses to microorganisms isolated from MJ. The spectrum of illnesses included one patient with systemic aspergillosis and seven patients with a history of bronchospasm after the smoking of MJ. Twenty-one smokers were asymptomatic. Fungi were identified in 13 of 14 MJ samples and included Aspergillus fumigatus, A. flavus, A. niger, Mucor, Penicillium, and thermophilic actinomycetes. Precipitins to Aspergillus antigens were found in 13 of 23 smokers and in one of 10 controls, while significant blastogenesis to Aspergillus was demonstrated in only three of 23 MJ smokers. When samples were smoked into an Andersen air sampler, A. fumigatus passed easily through contaminated MJ cigarettes. Thus the use of MJ assumes the risks of both fungal exposure and infection, as well as the possible induction of a variety of immunologic lung disorders.