慢粒白血病abl癌基因表达的研究

选择分别位于ｂｃｒ／ａｂｌ嵌合基因的Ｍｂｃｒｌ第二外显子和ａｂｌ的第二外显子上的两条引物，对１８例慢粒白血病及２例急淋白血病标本进行逆转录ＰＣＲ（ＲＴ－ＰＣＲ）检测。结果：在１８例包括ｐｈ（＋）和ｐｈ（－）不同病期的慢粒白血病患者血中均检出ｂｃｒ／ａｂｌ嵌合基因的表达，其中１４例为Ｋ－２８型表达，１例为Ｌ－６型表达，３例为Ｋ－２８型，Ｌ－６型同时表达；２例急淋白血病标本中１例为Ｋ－２８型表达。研究结果表明，１．ｂｃｒ／ａｂｌ嵌合基因是慢粒白血病的一个重要分子生物学特征；２．ｐｈ（＋）和ｐｈ（－）慢粒白血病的分子生物学基础相同，即均有ｂｃｒ／ａｂｌ嵌合基因；３．至少部分急淋白血病与慢粒白血病有相同的分子生物学基础；４．ｂｃｒ的断裂点位置可能有一定的临床意义，但有待进一步研究；５．同时表达Ｌ－６型和Ｋ－２８型的情况多见于急变区，此现象提示体内可能同时有两类不同嵌合的白血病细胞或白血病急变期ｂｃｒ出现新的重排。     

A cation binding motif stabilizes the compound I radical of cytochrome c peroxidase.

Cytochrome c peroxidase reacts with peroxide to form compound I, which contains an oxyferryl heme and an indolyl radical at Trp-191. The indolyl free radical has a half-life of several hours at room temperature, and this remarkable stability is essential for the catalytic function of cytochrome c peroxidase. To probe the protein environment that stabilizes the compound I radical, we used site-directed mutagenesis to replace Trp-191 with Gly or Gln. Crystal structures of these mutants revealed a monovalent cation binding site in the cavity formerly occupied by the side chain of Trp-191. Comparison of this site with those found in other known cation binding enzymes shows that the Trp-191 side chain resides in a consensus K+ binding site. Electrostatic potential calculations indicate that the cation binding site is created by partial negative charges at the backbone carbonyl oxygen atoms of residues 175 and 177, the carboxyl end of a long alpha-helix (residues 165-175), the heme propionates, and the carboxylate side chain of Asp-235. These features create a negative potential that envelops the side chain of Trp-191; the calculated free energy change for cation binding in this site is -27 kcal/mol (1 cal = 4.184J). This is more than sufficient to account for the stability of the Trp-191 radical, which our estimates suggest is stabilized by 7.8 kcal/mol relative to a Trp radical in solution.     

Subtypes of alpha 1-adrenoceptors in rat blood vessels

Two alpha 1-adrenoceptor subtypes (alpha 1A and alpha 1B) have been distinguished by competitive antagonists and the alkylating agent chloroethylclonidine. The chloroethylclonidine-insensitive subtype (alpha 1A) has been suggested to selectively activate Ca2+ influx through dihydropyridine-sensitive channels in smooth muscle. We compared the effects of chloroethylclonidine and nifedipine on contractile responses to norepinephrine (NE) in rat blood vessels. Pretreatment with chloroethylclonidine caused a large shift to the right and decrease in maximum for NE-induced contractions of rat aorta, however, nifedipine had no effect in this tissue. Chloroethylclonidine had no effect on NE-induced contractions of rat renal arteries, which were almost completely abolished by nifedipine. Both chloroethylclonidine and nifedipine partially attenuated NE-induced contractions in rat mesenteric artery and portal vein. Addition of nifedipine abolished residual contractions remaining after chloroethylclonidine pretreatment in all four types of vessels. The pA2 for the competitive antagonist WB 4101 was highest in renal artery and lowest in aorta. These results suggest that the sensitivity of rat blood vessels to chloroethylclonidine is inversely related to their sensitivity to nifedipine, and support the existence of two alpha 1-adrenoceptor subtypes in rat blood vessels. Rat aorta appears to contain primarily alpha 1B receptors, renal artery primarily alpha 1A, and mesenteric artery and portal vein mixtures alpha 1A of and alpha 1B.     

鼻内法鼻泪管阻塞切除术

本文介绍了鼻内法鼻泪管逆行切除术的切除器制备、应用器械、手术方法及术后处理。并应用本法治疗慢性泪囊炎１０６例１１３眼，术后随访１￣５年，痊愈９３．８％，无效６．２％。     

神经网络分析方法用于心脏病诊断的研究

神经网络可以很好的拟合任意的非线性函数。我们从 QRS波群的高频三维频谱中提取出一些定量的特征参数 ,用神经网络的方法对这些参数进行有监督的学习训练 ,最终能在由这些特征参数张成的 m维空间中构建出一个 m维的曲面来区分病人和健康人的 QRS波群高频三维频谱 ,从而使得训练后的网络能基于 QRS波群的高频三维频谱自行诊断出病人和健康人     

腹腔镜在胃癌根治术的应用进展

近年来有关早期胃癌的微创治疗进展很快，并已取得国内外的共识。对进展期胃癌应用腹腔镜行胃癌根治术尽管已经取得了较好的临床效果，但仍尚待前瞻性多中心临床随机对照研究。从应用前景看，随着术者技术的完善、观念的改变、经验的积累、手术器械的不断改进，腹腔镜胃癌根治术必将在胃癌手术中扮演越来越重要的角色。     

p21对缺血-再灌注损伤后肾小管上皮细胞演变的影响

目的 探讨p21对缺血-再灌注损伤（IRI）后肾小管上皮细胞演变的影响。方法 选择低龄（2个月龄）和高龄（12个月龄）p21（＋／＋）和p21（-／-）鼠，建立左肾IRI模型。于IRI后0、1、3、7d及1、3、6个月光镜下观察肾小管组织学变化，采用免疫组化法检测肾小管上皮细胞增殖细胞核抗原（PCNA）表达，组织化学染色观察肾小管上皮细胞衰老相关β-半乳糖苷酶（SA-β-gal）活力，末端脱氧核糖转移酶介导的生物素化脱氧尿嘧啶缺刻标记技术（TUNEL）检测肾小管上皮细胞凋亡。结果 IRI后0d，肾小管以坏死为主，高龄鼠比低龄鼠严重、p21（-／-）鼠比p21（＋／＋）鼠严重（P均〈0．05）。肾小管上皮细胞凋亡在IRI 1d后出现，7d达高峰，且高龄鼠比低龄鼠明显、p21（-／-）鼠比p21（＋／＋）鼠明显（P均d0．05）。低龄鼠IRI后1个月出现SA—β-gal染色阳性的肾小管上皮细胞，而对侧肾此时未见衰老细胞，3和6个月时衰老的肾小管上皮细胞显著增多，且p21（＋／＋）鼠比p21（-／-）鼠明显（P〈0．05）；p21（＋／＋）高龄鼠IRI后0d双肾即可见大量的SA-β-gal染色阳性肾小管上皮细胞，且较p21（-／-）鼠显著增多（P〈O．05），但1d后，p21（＋／＋）和p21（-／-）鼠IRI肾衰老细胞均明显减少（P均〈0．05），1个月后又呈进行性增加，且p21（＋／＋）鼠始终比p21（-／-）鼠严重。高龄和低龄p21（＋／＋）鼠PCNA阳性染色细胞出现的几率差异无显著性（P〉0．05），但低龄鼠细胞增殖能力要强于高龄鼠；而p21（-／-）鼠的细胞增殖能力明显强于p21（＋／＋）鼠，低龄鼠更为显著（P均〈0．05）。对高龄鼠IRI后1d细胞衰老和凋亡进行相关分析显示，二者呈显著负相关Cp21（＋／＋）鼠：r=-0．82，P〈0．001,p21（-／-）鼠：r=-0．76，P〈0．0013。结论 ①IRI可促进正常肾小管上皮细胞衰老的进程；②已经进入衰老状态的肾小管上皮细胞在遭受IRI刺激后，更易走向死亡[坏死和（或）凋亡]；③p21在IRI所致肾小管上皮细胞演变过程中发挥重要的调控作用。     

新基因Tctex5在雄鼠生殖细胞中的表达

目的探讨雄鼠生殖细胞中是否有Tctex5基因的表达。方法从三株体外培养的雄鼠生殖细胞CRL-1715、CRL-2053和CRL-2196细胞株中提取总RNA和蛋白，采用RT-PCR和Western blot分别从mRNA和蛋白质水平分析基因产物的表达。结果Tctex5基因在CRL-1715、CRL-2053、CRL-2196三株细胞中都有高表达。结论Tctex5基因作为一个未知功能的基因，在雄鼠生殖细胞中有丰富的表达，可能参与了精子发生的功能调节，作为男性正常生育的。个新的标志物，它可能在精子发生中扮演了一个重要的角色，该基因在雄性生殖细胞中的发现可能会对男性不育的诊断与治疗提供新的途径。