Distribution of glutathione and glutathione-related enzyme systems in mitochondria and cytosol of cultured cerebellar astrocytes and granule cells

The cellular and regional distribution of glutathione (GSH) and GSH-related enzyme systems involved in cellular defense against reactive oxygen species and electrophilic xenobiotics in the nervous system has been extensively studied. However, little is known about the subcellular distribution of GSH systems in brain tissue and cultured neural cells. The present study investigates the distribution of mitochondrial and cytosolic GSH and GSH-related enzymes in cultured cerebellar astrocytes and granule cells, and compares them with levels in the adult rat cerebellum. Cytosolic GSH levels and cytosolic activities of glutathione reductase (GR), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) in astrocytes were 57, 153, 245, and 92% higher than those found in granule cells, respectively. In contrast, granule cells contained significantly higher mitochondrial GSH levels than astrocytes. Granule cells also demonstrated comparable mitochondria/cytosolic concentrations of GSH and GR, GPX and GST activities to those observed in the cerebellar tissue, whereas ratios in astrocytes were markedly lower. Although in vitro treatments with 100 μM ethacrynic acid depleted both cytosolic and mitochondrial GSH in cultured astrocytes and granule cells in a time-dependent fashion, cellular GSH in granule cells was more resistant to the GSH-depleting agent than astrocytes. These results suggest that although GSH and GSH-related enzymes are abundant in cytosolic compartments of astrocytes, mitochondrial pools are relatively small. Since brain mitochondria are sites of significant hydrogen peroxide generation, the mitochondrial localization of GSH and its associated enzymes in neural cells provide important defenses against toxic oxygen species in the nervous system. Differences in subcellular distribution of GSH systems in individual neural cell types may provide a basis for selective cellular and/or subcellular expression of neurotoxicity.     

Regeneration of kidney tubular epithelial cells

Conclusion The mechanisms that regulate regeneration of kidney epithelial cells after acute tubular necrosis are poorly understood. Repair of the nephron can take place in the adverse systemic metabolic setting caused by failure of renal function. This clinical observation suggests that factors released at the site of the tubular insult can mediate repair. Studies carried out in this and other laboratories show that kidney epithelial cells can release and respond to polypeptide growth factors which may thereby contribute to renal regeneration by autocrine and paracrine mechanisms. Specific growth factors secreted by cells and deposited in the tubular basement membrane prior to injury may subsequently participate in nephron repair. In addition, adenine nucleotides released from injured or dying cells at the injury site or provided exogenously could stimulate surviving renal epithelial cells at the edges of the wound to migrate along the basement membrane to rapidly reepithelialize the nephron and subsequently initiate mitogenesis to replace cells lost by necrosis.The nephrotoxic effect of many agents used in cancer chemotherapy and the older age of patients undergoing complicated surgical procedures has increased the incidence of ARF, whereas the mortality rate has not changed since the early 1950s [22]. Thus there is considerable need for innovative therapeutic strategies. An important goal of future research efforts is to identify new growth factors that facilitate migration, differentiation, and proliferation of renal epithelial cells at sites of tubular necrosis. Isolation and use of these agents in combination with dialysis and nutritional support could speed renal regeneration and thereby improve the outcome in patients with this condition.Abbreviations ARF acute renal failure - ECM extracellular matrix - EGF epidermal growth factor - FGF fibroblast growth factor - IGF insulin-like growth factor - MGSA melanocyte growth-stimulating activity - PDGF platelet-derived growth factor - IGF transforming growth factor     

二甲亚砜对人表皮的核酸和蛋白质合成的影响

用体外培养的人的伪表皮作为模型，进行药物毒理学作用的研究，观察了二甲亚砜（ＤＭＳＯ）在不同浓度和不同接触时间条件下，对人的伪表皮细胞脱氧核糖核酸（ＤＮＡ）、核糖核酸（ＲＮＡ）和蛋白质合成的影响：随着接触时间的延长，ＤＮＡ、ＲＮＡ和蛋白质合成均受抑制。低浓度条件下（１％），ＤＮＡ、ＲＮＡ和蛋白质合成增加；在１５～５０％浓度下，ＤＮＡ和蛋白质合成抑制，而ＲＮＡ合成仍增加；在高浓度条件下（７０％～１００％），ＤＮＡ、ＲＮＡ和蛋白质合成均明显抑制。     

Isolation and identification of chondroitin sulfates from the mud snail

Chondroitin sulfates were isolated from the mud snail. For the quantitative analysis of enzymatic digestion products of isolated chondroitin sulfates, strong anion exchange-high performance liquid chromatography (SAX-HPLC) was performed. By the action of chondroitinase ABC, three unsaturated disaccharides 2-acetamide-2-deoxy-3-O-(β-D-gluco-4-enepyranosyluronic acid)-D-galactose (ΔDi-OS), 2-acetamide-2-deoxy-3-O-(β-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose (ΔDi-6S) and 2-acetamide-2-deoxy-3-O-(β-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose (ΔDi-4S) were produced from the mud snail chondroitin sulfates. The analysis showed that relative proportion of ΔDi-OS/ΔDi-6S/ΔDi-4S was 58.7/3.1/38.2. The immunomodulating activity of chondroitin sulfate was examined by cell proliferation assay and these results suggest that it might be a immunosuppressant.     

Morphologic characterization of osteoblast-like cell cultures isolated from newborn rat calvaria

Summary Two methods for harvesting osteoblast-like cell populations from newborn (10 days) rat calvaria were compared. The first one consisted in culturing the periosteum-free bones and then trypsinizing the cells on the bone surface. The second one involved the migration of the osteoblasts on glass fragments before trypsinization. Since the plating efficiency, the proportion of alkaline phosphatase-positive cells, the population doubling time, and the calcium deposition were more adequate, the second method was used to further characterize the behavior of the cultures. During the first week of culture, the cells featured shapes similar to those observedin vivo on the surface of periosteum-free calvaria. They formed multilayers and, in the presence of ascorbic acid, synthetized an organic matrix containing exclusively type I collagen. Later, small amounts of type III collagen appeared. The cells were embedded in the matrix and progressively acquired the morphologic phenotype of osteocyte-like cells. The matrix mineralized in the presence of β-glycerophosphate. The technique of dropinoculation (high concentration of cells in a small volume of medium) promoted the multilayer formation and the achievement of large mineralized plates (about 1 cm²) in 3 weeks of culture.     

PsD007对四株NPC细胞放射敏感性的影响

采用ＭＴＴ方法观察癌光啉结合＾６０Ｃｏγ射线放射对四株人鼻咽癌细胞体外放射增敏作用，结果表明在一定的ＰｓＤ００７浓度范围内，随ＰｓＤ００７浓度的升高，放射对细胞的杀灭作用明显增强，当浓度分别为１．２５，６．２５，１２．５，２５和５０μｇ／ｍｌ时，对四株细胞杀灭增加倍数分别为１．０１－１．０６，１．１５－１．２９，１．２８－１．５９，１．７９－３．１８，２．８６－５．５５；放射量效存活曲线按多靶单击     

细胞内钙信号的变化调节血管平滑肌细胞增殖

目的探讨细胞内钙信号的变化对大鼠血管平滑肌细胞(VSMC)增殖作用的影响及其对细胞内信号转导机制的变化。方法以培养的大鼠VSMC为模型,用雷尼丁(RY)剌激VSMC内贮Ca2 释放入胞浆,用3H亮氨酸及3H胸腺嘧啶掺入量作为反应VSMC增殖的指标,加入不同的细胞内信号转导阻断剂,观察对RY效应的影响。结果与对照组相比,RY浓度依赖性地促进细胞内游离钙浓度的增高,差异显著(P<0.05或0.01)。RY剌激组蛋白核酸合成速率明显增高,与对照组相比差异显著(P<0.01);尼卡地平(Nicardipine),蛋白激酶C抑制剂(H7),钙调素激酶(CaMPK)抑制剂(W7)和丝裂素活化蛋白激酶(MAPK)抑制剂(PD98059)能明显抑制RY介导的VSMC蛋白核酸合成速率增高,与RY剌激组相比差异显著(P<0.01)。结论细胞内钙信号的变化明显促进VSMC增殖,但其效应可能通过Ca2 、PKC、MAPK来介导。钙离子拮抗剂可抑制血管平滑肌细胞增殖。     

动态旋转系统构建组织工程化血管模型中血管内皮细胞分泌功能监测

目的 比较静态和动态旋转系统中构建组织工程化血管模型中血管内皮细胞分泌功能。方法新型可降解材料聚羟基丁酸酯(PHB),用胶原包埋,形成多孔状PHB 胶原管形支架。分离传代、分化人脐静脉内皮细胞,接种于PHB管型支架内腔面,分别在静态、动态旋转系统中培养14 d后,测定血管内皮细胞分泌一氧化氮(NO)、前列环素(PGI2)水平。结果 在动态旋转系统构建组织工程化血管模型中血管内皮细胞分泌NO、PGI2水平显著高于静态系统,在11 d NO分别为(120.52±3.83)μmmol／L、(80.98±5.98)μmmol／L,PGI2分另9为(20.48±1.52)μg／L,(16.59±1.29)μg／L,与静态系统相比,差异有显著性(P<0.05)。结论胶原包埋PHB支架有利于细胞的黏附和生长,可作为组织工程化血管的支架材料。在动态旋转系统构建组织工程化血管模型中血管内皮细胞,具有与正常血管类似的"生理功能"。     

电离辐射调控脂质体介导的p16基因在HeLa细胞中的表达

目的探讨不同剂量γ射线照射后诱导脂质体介导的p16基因在HeLa细胞中的表达及抗癌作用。方法用脂质体Lipofectamin介导重组质粒Egr-p16转染人HeLa细胞，采用RT-PCR的方法检测了。Coγ射线照射转染后的人HeLa细胞剂量效应和时程变化，用细胞计数检测细胞增殖的变化，用流式细胞术检测细胞周期的变化。结果研究证实0．5～8Gv照射后p16的转录水平高于对照，在2～4Gy照射后达到峰值，2Gy照射后2—24h高于对照组，在照射后4h达到峰值，然后逐渐下降。细胞生长曲线显示体外稳定转染联合。Coγ射线照射对HeLa细胞的增殖具有明显的抑制作用。细胞周期变化显示转染后的HeLa细胞经过照射后G0／G1期比例呈现剂量依赖性的下降，而S期则出现剂量依赖性的增加，出现明显的S期阻滞，G2／M期在2Gy出现明显的阻滞，在5和10Gy时逐渐下降，但是仍然高于对照组。结论^60Coγ射线可诱导转染的HeLa细胞p16转录水平的增强，同时在细胞增殖上出现明显的变化。     

试论图书馆与医院文化建设

通过对医院化概念的解释、医院图书馆与医院化的关系及医院图书馆在医院化建设中的作用等方面论述了医院化为医院图书馆的发展提供了良好的基础，医院图书馆为营造医院化氛围起到了潜移默化的作用。医院图书馆是医院化建设的重要组成部分。