Calcium-activated proteolysis of intracellular domains in the cell adhesion molecules NCAM and N-cadherin.

One of the consequences of increased intracellular calcium in response to a variety of physiological stimuli is the calcium activation of cytosolic proteases. Unlike lysosomal proteases with broad specificity, these calcium-activated neutral proteases show limited proteolysis of a restricted set of substrate proteins suggesting they may play a regulatory role in cellular physiology. In this study we show that the neural cell adhesion molecules NCAM-180 and N-cadherin are substrates for such endogenous calcium-activated neutral proteases. In contrast, a third neural cell adhesion molecule G4/L1 was not susceptible to calcium-activated proteolysis. The threshold for activation of NCAM and N-cadherin proteolysis is in the micromolar range of calcium suggesting that NCAM and N-cadherin are substrates for a mu-type calpain (calpain I). The site recognized by this protease is within intracellular domains of NCAM-180 and N-cadherin which are important for their interaction with cytoskeletal components. These results suggest that calcium-activated proteolysis at these sites in vivo could disrupt the linkage between extracellular ligand binding to these adhesion molecules and the normal intracellular effectors of such extracellular binding events.     

哮喘患儿血清嗜酸性粒细胞阳离子蛋白改变及其意义

目的：评价变应性哮喘患儿血清嗜酸性粒细胞阳离子蛋白（S-ECP）水平改变及其意义。方法：测定25例哮喘发作期患儿糖皮质激素吸入治疗12周前后，及20例未予糖皮质激素吸入治疗的哮喘缓解期患儿S-ECP水平，并对发作期患儿S-ECP水平变化与血嗜酸性粒细胞计数（B-EOS）、肺功能一秒用力呼气量（FEV1）、一秒用力呼气量比用力肺活量（FEV1/FVC）及症状评分的关系作相关性分析。结果：哮喘发作组治疗后S-ECP水平较治疗前显著降低，与对照组（健康儿童10名）比较差异无显著性；哮喘缓解组S-ECP水平明显高于发作组治疗后，但明显低于发作组治疗前。哮喘发作组治疗前S-ECP水平变化与B-EOS无相关性，与FEV1、FEV1/FVC呈负相关，与症状评分呈正相关。结论：监测S-ECP水平可作为评价哮喘气道炎症程度、病情预后和指导抗炎治疗的有效指标。     

Intracellular Ca2+ suppressed a transient potassium current in hippocampal neurons

The effects of intracellular Ca2+ (Ca2+i) on K+ currents in hippocampal cells were examined using acutely isolated cells obtained from adult guinea pigs. Whole-cell voltage-clamp recordings were carried out in a configuration that allowed a continuous perfusion of the intracellular medium. Recording media were made to block inward currents and allowed selective activation of K(+)-dependent outward currents. Voltage-dependent outward currents consisted of an initial rapidly decaying component followed by a sustained component. The time constant of decay of the transient current was about 25 msec, and previous studies (Numann et al., 1987) showed that the kinetic and pharmacological properties of this current closely resembled the A current recorded in invertebrate neurons (Connor and Stevens, 1971; Thompson, 1982). Intracellular perfusion of hippocampal cells with a solution containing elevated Ca2+ (about 4.5 x 10(-4) M) elicited outward currents at the holding potential (-45 to -55 mV) and produced changes in voltage-dependent K+ currents. The transient outward current (IA) activated by depolarization was suppressed with increases in Ca2+i. Delayed, sustained K+ currents were greatly potentiated. Data also showed that, among the 3 effects elicited by Ca2+i, suppression of IA was most sensitive to Ca2+i elevation. Previous results (Numann et al., 1987) showed that IA had a lower threshold (about -45 mV) than sustained currents (about -40 mV). By using low levels of depolarization (-40 mV), IA can be selectively activated, and the suppressive effect of Ca2+i on IA was confirmed on the kinetically isolated IA.(ABSTRACT TRUNCATED AT 250 WORDS)     

Treatment of ulcerative colitis by traditional Chinese medicine and dynamic study of immune functions

The effect of the traditional Chinese medicinal herbs enema and enteric-coated capsules in the treatment of ulcerative colitis (UC) were compared in 260 cases. The immune complexes and the dynamic change of autoantibodies were monitored in 28 out of the 260 cases before and after treatment. The following results were observed. (1) There was no significant difference in the total effective rate between the enema group and the oral capsule group (93.3% and 87.5% respectively), but the recovery rates of purulent hemafecia, mucusfecia and erosion accompanying colitis, etc. in the former group were higher than those in the latter (P less than 0.01). (2) The circulating immune complexes were found 43 times above the normal range in 17 cases with positive rate 60.7%, and tended to decrease as the condition became better after treatment. Antinuclear antibodies were determined by the indirect fluorescent immune method and the indirect enzyme labelling method and the positive rates were 53.6% and 64.7% respectively, both being much higher than those in the controls (P less than 0.01).     

乳腺影像学报告及数据系统:超声良恶性病变鉴别诊断初探

1992年美国放射学会制定了乳腺影像学报告及数据系统(breast imaging reporting and data system,BI-RADS),2003年第四版修订时包括了超声诊断(BI-RADS-US)。本文旨在初步探讨BI-RADS-US对于乳腺良恶性病变鉴别诊断的能力。我们收集了2006年1月至2007年3月期间、获得病理诊断的乳腺占位性病变共69例72灶。均为女性,年龄14-83岁,平均41.6岁。首先根据一般的非BI-RADS标准,做出良恶性鉴别。然后用BI-RADS-US标准进行鉴别和分级(0-6级),其中2级和3级为良性和良性可能性大,4级为性质待定,5级为恶性可能性大。计算并比较上述两种方法的准确性、敏感性、特异性。结果在72病灶中,根据非BI-RADS标准,诊断为良性者40灶,符合病理诊断者38灶(95.0%),诊断为恶性者23灶,符合病理者18灶(78.3%);诊断为性质待定者9灶。根据BI-RADS-US标准和分级,2级和3级共有37灶,与病理结果符合者为36灶(97.2%);5级有31灶,与病理符合者为22灶(71.0%);4级有4灶。非BI-RADS和BI-RADS-US的准确性各为83.3%和81.9%(P=1.000),敏感性各为91.7%和95.8%(P=1.000),特异性各为79.2%和75.0%(P=0.754)。总之,第一版BI-RADS-US在乳腺良恶性病变鉴别诊断方面的初步应用表现出较高的敏感性,而与非BI-RADS方法比较则尚无明显差别。     

中药抗病毒性心肌炎的实验研究现状

病毒性心肌炎(VMC)近年发病呈上趋势,严重危害人民身体健康,中医药在治疗方面有很好的优势,目前学者们在中医药治疗病毒性心肌炎的实验研究方面作了很深入的工作,现就中药抗病毒性心肌炎的实验研究现状做一综述。     

血液透析动脉穿刺术临床研究

目的:研究动脉穿刺技术,提高1次穿刺成功率。方法:将166例急、慢性肾功能衷竭接受血液透析的患者,随机分为观察组84例和对照组82例。观察组用新的穿刺方法,即先在动脉(桡动脉或足背动脉)搏动最明显或最清晰处按一印记,然后进针,对照组用传统的穿刺方法穿刺。比较两组所需时间、1次成功率、血流量、针眼处渗血、疼痛程度以及并发症。结果:两组穿刺所需时间、血流量、针眼处渗血,均有统计学意义(P<0.01)。结论:观察组用新的穿刺方法,能明显提高1次穿刺成功率,缩短穿刺时间,减轻患者痛苦,减少并发症发生。