蒙药绿松石的质量标准研究＊

目的 建立蒙药绿松石的质量标准。方法 收集不同产地绿松石，共10批。观察绿松石样品和粉末的性状并进行理化鉴别；按2020年版《中国药典》（四部）通则方法测定绿松石样品中水分、浸出物含量；采用原子吸收光谱法测定绿松石样品铜元素含量。结果 绿松石为不规则、周围带有黑石的块状物，表面蓝绿色，体重，质硬脆，难砸碎，断面呈贝壳状，蜡样光泽，粉末呈灰绿色，无臭，味淡；理化鉴别结果显示，呈铜盐反应；10批次样品中水分含量为0.41%-3.94%（SD=1.37%），浸出物含量为0.21%-0.81%（SD=0.21%），铜元素含量为3.03%-4.63%（SD=0.63%）。结论 初步拟定绿松石中水分含量不得超多5.0%、浸出物含量不得低于0.10%，铜元素含量应为2.60%-4.84%，制定的标准可用于蒙药材绿松石的质量控制。     

T cell response of I-Aq mice to self type II collagen: meshing of the binding motif of the I-Aq molecule with repetitive sequences results in autoreactivity to multiple epitopes

Type II collagen (CII) is of immunological interest because of its repetitive structure and properties as an autoantigen. The mouse gene has recently been cloned, thus enabling T cell-defined epitopes to be identified. Multiple novel epitopes on mouse CII are here detected in the autoreactive T cell response. The major response is directed to an epitope with residues 707-721 located on the CB10 fragment. Some 25 other epitopes are also recognized, including the autologous homologue of the 256-270 epitope which dominates in the response to foreign collagen. The cells reactive with mouse collagen peptides were of Th1 type, as judged by release of IFN-gamma. No significant reactivity was detected to mouse CII peptides during ongoing disease. Alignment of the mouse epitopes revealed a sequence motif with characteristic side chains at residues P1, P4 and P7, and to a lesser extent at P5, within a nonamer core sequence. Binding of these epitopes was simulated in a computer model of the I-Aq molecule, where peptides with anchor residues at P1, P4 and P7 were indeed found to fit the binding groove best. The spacing of pockets and the fine structure of the binding surface of the I-Aq molecule meshes with the repetitive structure of the collagen (X-Y-Gly), thus providing a likely explanation for the occurrence of multiple epitopes. Comparison with human DR binding motifs showed that the I-Aq motif resembles most closely that of the DR4 subtypes which predispose for rheumatoid arthritis.      

北方汉族人群维生素D受体基因Bsm I位点多态性与前列腺癌易感性的相关性分析

目的 :研究低发病的中国汉族人群维生素D受体基因 (VDRG)BsmⅠ 位点单核苷酸多态性 (SNP)与前列腺癌的关系 ,探讨不同种族前列腺癌发病的基因差异。　方法 :收集中国北方地区汉族人群 10 3例前列腺癌病人及10 6例健康对照者外周血标本 ,应用变性高效液相色谱 (DHPLC)检测VDRG第 8内含子BsmⅠ多态位点 ,并对该位点SNP分布进行分析。　结果 :BsmⅠ 多态位点bb、Bb、BB基因型和等位基因在北方地区汉族前列腺癌病人及对照者中的分布频率差异无显著性 (P >0 .0 5 ) ,基因型分布频率分别为 92 .2 3%、7.77%、0和 94.34 %、5 .6 6 %、0 ;等位基因B、b分别为 3.88%、96 .12 %和 2 .91%、97.0 9%,而与高发病人群的分布相比有显著不同。　结论 :VDRGBsmⅠ多态性在低发病的中国汉族人群与前列腺癌无相关 ,其分布与高发病人群有明显差异 ,提示VDRGBsmⅠ多态性可能是前列腺癌发病种族差异的原因之一。     

Novel proteins with binding specificity for DNA CTG repeats and RNA CUG repeats: implications for myotonic dystrophy

While an unstable CTG triplet repeat expansion is responsible for myotonic dystrophy, the mechanism whereby this genetic defect induces the disease remains unknown. To detect proteins binding to CTG triplet repeats, we performed bandshift analysis using as probes double- stranded DNA fragments having CTG repeats [ds(CTG)6-10] and single- stranded oligonucleotides having CTG repeats ss(CTG)8 or RNA CUG triplet repeats (CUG)8. The source of protein was nuclear and cytoplasmic extracts of HeLa cells, fibroblasts and myotubes. Proteins binding to the double-stranded DNA repeat [ds(CTG)6-10], were inhibited by nonlabeled ds(CTG)6-10, but not by a non-specific DNA fragment (USF/AD-ML). Another protein binding to ssCTG probe and RNA CUG probe was inhibited by nonlabeled (CTG)8 and (CUG)8. Nonlabeled oligos with different triplet repeat sequences, ss(CAG)8 or ss(CGG)8, did not inhibit binding to the ss(CTG)8 probe. However, when labeled as probes, the (CAG)8 and (CGG)8 bound to proteins distinct from the CTG proteins and binding was inhibited by nonlabeled (CAG)8 or (CGG)8 respectively. The protein binding only to the RNA repeat (CUG)8 was inhibited by nonlabeled (CUG)8 but not by nonlabeled single- or double-stranded CTG repeats. Furthermore, the CUG-BP exhibited no binding to an RNA oligonucleotide of triplet repeats of the same length but having a different sequence, CGG. The CUG binding protein was localized to the cytoplasm, whereas dsDNA binding proteins were localized to the nuclear extract. Thus, several trinucleotide binding proteins exist and their specificity is determined by the triplet sequence. The novel protein, CUG-BP, is particularly interesting since it binds to triplet repeats known to be present in myotonin protein kinase mRNA which is responsible for myotonic dystrophy.