Direct effect of cadmium on citrate uptake by isolated rat renal brush border membrane vesicles

High incidence of multiple kidney stone formation has been observed among workers exposed to cadmium (Cd). Citrate is known to be a protective factor against renal stone formation. To study the direct effect of cadmium on citrate uptake by the renal brush border membrane, we exposed isolated rat renal brush border membrane vesicles (BBMV) to cadmium and determined their citrate uptake characteristics. BBMV were prepared by the divalent cation precipitation method. Citrate uptake was measured by the Millipore rapid membrane filtration technique. Preincubation of BBMV with 2 and 10 mM CdCl₂ for 1 min significantly inhibited citrate uptake compared with that of BBMV without Cd. Analysis of the time course of citrate uptake during 30-min preincubation of BBMV with 0.5 mM Cd also revealed significant reduction of the uptake compared with that of the control BBMV without preincubation. These findings indicate that preincubation of BBMV with cadmium results in time-dependent and concentration-dependent inhibition of citrate uptake.     

小鼠宫颈癌腹水瘤U_(14)及其亚株侵袭特性的初步研究

本文将小鼠宫颈癌腹水瘤u_(14)和经本教研室活体筛选出的倾向于肺转移的u_(14)A-P_(11)和倾向于淋巴转移的u_(14)-AL_(10)两亚株,用鸡胚绒毛尿囊膜接种的体内方法和与经胰酶不同处理的BALB/C小鼠腹膜组织共同培养的体外方法,对三种瘤细胞的侵袭特性进行研究。结果证明,三种瘤细胞体内转移倾向的差异与其对鸡胚绒毛尿囊膜基质和小鼠腹膜基质的侵袭能力成正相关,表明瘤细胞转移的器官倾向性与瘤细胞的侵袭力有一定的关系。     

胰腺癌细胞的增殖同膜脂质饱和度,膜胰岛素受体的关系

外源性表皮生长因子(或生长抑素)能促进(或抑制)胰腺癌细胞的增殖。胰腺癌细胞增殖速率的高低与细胞膜脂质饱和度的降、升;与膜胰岛素受体数量的增减密切相关。测定细胞膜脂质饱和度和胰岛素受体数量,是判断胰腺癌增殖状态的灵敏指标,有一定临床价值。     

聚芳醚砜薄膜的气体透过行为

研究了一系列聚芳醚砜的Ｈ２、ＣＯ２、Ｏ２、Ｎ２和ＣＨ４气体透过性能，讨论了其气体透过的温度依赖性。与双酚Ａ聚砜（ＰＳＦ）相比，几种新型聚芳醚砜的气体透过系数和气体选择系数同时有所提高。通过聚合物的分子链段活动性和自由体积数据系列变化，讨论了气体透过速率与分子结构的关系。     

K~+ Channels and Their Effects on Membrane Potential in Rat Bronchial Smooth Muscle Cells

In order to investigate the K~+ channels and their effects on resting membrane potential(Em) and excitability in rat bronchial smooth muscle cells (BSMCs), the components of outward K~+channel currents and the effects of K~+ channels on Em and tension in rat bronchial smooth musclewere observed by using standard whole-cell recording of patch clamp and isometric tension recordingtechniques. The results showed that under resting conditions, total outward K~+ channel currents infreshly isolated BSMCs were unaffected by ATP-sensitive K~+ channel blocker. There were two typesof K~+ currents: voltage-dependent delayed rectifier K~+ channel (Kv) and large conductance calcium-activated K~+ channel (BK_(Ca)) currents. 1 mmol/L 4-aminopyridine (4-AP, an inhibitor of Kv)caused a significant depolarization (from — 8.7±5.9mV to —25.4±3.1mV, n=18, P<0.001).In contrast, 1 mmol/L tetraethylammonium (TEA, an inhibitor of BK_(Ca)) had no significant effect onEm (from —37.6±4.8 mV to —36.8±4.1 mV, n=12, P>0.05). 4     

Cloning and expression of SLC1OA4,a putative organic anion transport protein

AIM:To determine if novel bile acid transporters may be expressed in human tissues.METHODS:SLC10A1 (NTCP) was used as a probe to search the NCBI database for homology to previously uncharacterized ESTs. The homology search identified an EST (termed SLC10A4) that shares sequence identity with SLC10A1 and SLC10A2 (ASBT). We performed Northern blot analysis and RT-PCR to determine the tissue distribution of SLC10A4. SLC10A4 was cloned in frame with an epitope tag and overexpressed in CHO cells to determine cellular localization and functional analysis of bile acid uptake.RESULTS:Northern analysis revealed that SLC 10A4 mRNA is ubiquitously expressed fn human tissues with the highest levels of mRNA expression in brain,placenta, and liver. In SLC10A4-transfected CHO cells,immunoblotting analysis and immunofluorescence staining demonstrated a 49-kDa protein that is expressed at the plasma membrane and intracellular compartments.Functional analysis of SLC10A4 showed no significant taurocholate uptake in the presence of sodium when compared to untransfected CHO cells.CONCLUSION:To date, we have shown that this protein has no capacity to transport taurocholate relative to SLC1041; however, given its ubiquitous tissue distribution, it may play a more active role in transporting other endogenous organic anions.     

关节镜下滑膜切除术治疗膝滑膜结核的临床分析

目的：探讨关节镜下滑膜切除术治疗膝滑膜结核的疗效。方法：对我院1990年1月至2003年7月的23例膝关节滑膜结核的患者在关节镜下行滑膜切除术并取组织送病理检查。结果：术后经随访16—36个月，患者功能恢复良好，症状消失，优良率达到96．3％。结论：关节镜下滑膜切除术治疗膝关节滑膜结核是一种安全有效的治疗方法。     

Effects of Glucocorticoid on Electrical Activities of Hippocampal Neurons in vitro

Intracellular recording of the rat hippocampal slices was established and usedto analyse the effects of glucocorticoid on resting membrane potential as well as inputresistance of the cells in CA1 and CA2 of hippocampal slices.The results indicate thatwithin 1-2 min the steroid hyperpolarized some of the hippocampal neurons with atendency of increasing the cells' input resistance,suggesting that glucocorticoid caninfluence the function of central neurons in a non-genomic pattern,and the underlyingmechanism involves the change of resting membrane potential.     

Understanding the choroid

Based on previous work, this paper describes the anatomical and functional characteristics of the choroidal vasculature, namely the choriocapillaris, the arterial and arteriovenous anastomosis, the segmental distribution of the short posterior ciliary arteries, and the choroidal veins. The characteristics of the choroidal innervation with reference to the sensory nerve endings are reviewed. Some features of Bruch's membrane may explain the fundoscopic and angiographic appearance of the angioid streaks and the role of its basement membranes in the formation and transport of drusen.     

人血液酪氨酸蛋白激酶的研究——(Ⅲ)1—异丙基—6—氨基—噻吩骈[3,4—d]嘧啶—2,4—二酮对人淋巴细胞膜TPK活性的抑制作用

文报道了人工合成的1—异丙基—6—氨基—噻吩骈〔3,4—d〕嘧啶—2,4—二酮对人淋巴细胞膜TPK活性的抑制作用,IC_(50)约为300μmol/L。动力学实验结果表明,该化合物对TPK的抑制作用与ATP呈竞争性,而与多肽底物Poly(Glu—Ala—Tyr)_(6;3:1)呈非竞争性。放射自显影结果进一步证实了该化合物对TPK的抑制作用。