The probability that similar haplotypes are identical by descent

The logic of gene mapping in highly penetrant diseases is to find the minimal overlap of haplotypes that are identical by descent (IBD). If the pedigree is unknown, identity by descent of haplotype overlap cannot be established with certainty. In many cases, it is intuitively clear that similar haplotypes are indeed IBD. The logical and statistical evaluation of haplotype overlap requires that probabilities of IBD are substantial. It is, therefore, important to estimate these probabilities. In this paper, we derive a recursive formula for the probability of IBD. Simulations are used to validate the expected values and to study the variability around the expected value. We demonstrate that for populations 1000 generations of age – without bottlenecks – haplotypes of 1 cM consisting of at least five microsatellite markers have a significant probability to be IBD. Likewise, SNP haplotypes of 1 cM should consist of at least nine identical SNP alleles for a similar probability of IBD. Without considering bottlenecks, haplotypes consisting of as few as three SNPs spanning a region of less than 0.01 cM are likely IBD in populations that are 10000 generations of age.     

贯叶金丝桃愈伤组织的诱导及其有效成分的定性

目的 :诱导出贯叶金丝桃的愈伤组织 ,并确定其中含有金丝桃素。方法 :在不同条件下采用组织培养技术 ,进行贯叶金丝桃的愈伤组织诱导研究 ,用HPLC方法确定其中含有的金丝桃素。结果和结论 :最佳诱导条件是MS基本培养基加入生长调节物质 2 ,4 D(4μg·L- 1 )和 6 BA(0 .2 μg·L- 1 )。叶腋等分生组织较多的部位易于诱导愈伤组织。诱导出的愈伤组织 ,经HPLC方法确定其含金丝桃素     

简化注射用头孢菌素无菌检查法的探讨

目的:完善头孢菌素类药物注射剂的无菌检验方法标准。方法:以7种不同代注射用头孢菌素为例,通过对阳性对照菌,冲洗量及青霉素酶的加入顺序等条件的选择,建立了无菌检查方法。结果:不同代头孢菌素因抗菌谱的差异,对不同验证菌株的敏感性显著不同;无菌检查法必须建立在验证试验的基础上。结论:头孢菌素无菌检查方法的验证菌株可由目前2005年版中国药典规定的5株简化为2株,并从中选择最敏感的菌株作为无菌检查中的阳性菌株,即可保证无菌检查方法的有效性。     

加替沙星微生物限度检查方法的建立

目的:完善加替沙星微生物限度检查方法。方法:采用薄膜过滤并在培养基中加入中和剂(0.1 mol·L~(-1)的硫酸锰溶液)的方法,去除加替沙星的抗菌活性。结果:本方法满足中国药典2005版验证试验的基本要求。5株验证菌株中枯草芽孢杆菌对加替沙星最敏感,可作为加替沙星微生物限度检查方法的质控菌株。结论:该方法可作为加替沙星口服制剂的常规微生物限度检查方法。     

Potent induction of tumor immunity by combining tumor cryoablation with anti-CTLA-4 therapy

Thermal ablation to destroy tumor tissue may help activate tumor-specific T cells by elevating the presentation of tumor antigens to the immune system. However, the antitumor activity of these T cells may be restrained by their expression of the inhibitory T-cell coreceptor CTLA-4, the target of the recently U.S. Food and Drug Administration-approved antibody drug ipilumimab. By relieving this restraint, CTLA-4-blocking antibodies such as ipilumimab can promote tumor rejection, but the full scope of their most suitable applications has yet to be fully determined. In this study, we offer a preclinical proof-of-concept in the TRAMP C2 mouse model of prostate cancer that CTLA-4 blockade cooperates with cryoablation of a primary tumor to prevent the outgrowth of secondary tumors seeded by challenge at a distant site. Although growth of secondary tumors was unaffected by cryoablation alone, the combination treatment was sufficient to slow growth or trigger rejection. In addition, secondary tumors were highly infiltrated by CD4(+) T cells and CD8(+) T cells, and there was a significant increase in the ratio of intratumoral T effector cells to CD4(+)FoxP3(+) T regulatory cells, compared with monotherapy. These findings documented for the first time an effect of this immunotherapeutic intervention on the intratumoral accumulation and systemic expansion of CD8(+) T cells specific for the TRAMP C2-specific antigen SPAS-1. Although cryoablation is currently used to treat a targeted tumor nodule, our results suggest that combination therapy with CTLA-4 blockade will augment antitumor immunity and rejection of tumor metastases in this setting.