氟对人牙乳头间充质细胞及分泌碱性磷酸酶活性的影响

为了明确氟对人牙乳头间充质细胞和分泌碱性磷酸酶活性的影响 ,体外培养人牙乳头间充质细胞 ,给予不同浓度氟处理 :0 μmol,10 μmol(0 .2× 10 - 6 g/ L) ,5 2 μmol (1.0× 10 - 6 g/ L) ,2 6 3μmol(5 .0× 10 - 6 g/ L) ,1315 μmol (2 5×10 - 6 g/ L) ,2 6 30 μmol(5 0× 10 - 6 g/ L) ,用四唑盐比色法 (MTT法 )测定细胞活力 ,酶联免疫法检测碱性磷酸酶活性 ,结果显示 ,当氟浓度为 2 6 3μmol时 ,培养 2 4 h后 ,细胞活性明显抑制 ,AL P活性无明显改变 ;当氟浓度为 1315 μmol和2 6 30 μmol时 ,培养 12 h细胞活性明显抑制 ,分泌的 AL P活性升高 ,培养 72 h时 2 6 30 μmol氟浓度组几乎无活细胞 ,而AL P活性仍较对照组高 ,由此提示 ,氟作用于人牙乳头细胞时 ,细胞活性与 AL P活性升高不一致     

在酶系统中镁对氟毒性的拮抗研究进展

地方性氟中毒是危害人类健康的一种常见疾病,在防治饮水型氟中毒方面,一般采用改饮低氟水、化学和物理方法除氟以及用氟拮抗剂对症治疗的方法。目前已报道的抗氟元素有钙、镁、硒等,氟、镁关系的研究近年报道渐多,并有不同意见,但大多数学者认为镁对氟毒性具有拮抗作用,现对其在酶活性方面的拮抗作用做一综述。１镁调节酶活性并加强生物系统膜的结构 氟中毒时,机体许多酶活性被抑制［１］。由于机体内过量的氟离子结合了大量的镁离子,形成镁氟磷酸盐复合体排出体外,使以Ｍｇ２＋为辅助因子ＡＴＰ酶、Ｎａ＋、－Ｋ＋、－ＡＴＰ酶的…     

镁拮抗氟对细胞超微结构损伤观察

地方性氟中毒以脊柱及其周围韧带骨化所引起的椎管和椎间孔狭窄是广泛的。镁是一种与氟中毒流行关系密切的常量元素。ode′ll等指出在氟中毒流行区高镁摄入量对减低氟毒性是有效的。Merren曾报道在食物中镁与氟之间的相互关系能够影响人体软骨组织钙化。本实验以鸡胚肢软骨细胞做为氟中毒模型,通过亚细胞水平观察,研究氟对鸡胚软骨     

氟的细胞毒性作用

氟是一种具有细胞毒性的物质,也是人体必需的微量元素之一,摄入量过多或过少均会导致机体器官的病变。近年来,有关氟对细胞毒性作用的研究很多,由于各种细胞对氟的敏感性不同,因而氟表现出多种多样的细胞毒性作用。1氟对骨细胞的毒性作用1.1氟对成骨细胞的影响:氟是一种已知可影响骨形成的非激素因子,对骨形成具有双相调节作用。长期小剂量摄氟     

钙营养对氟的骨骼毒性的影响

用富钙平衡饲料和低钙偏食饲料分别饲养Ｗｉｓｔａｒ大鼠,并经饮水投予氟１００ｍｇ／Ｌ,为期４个月,以研究钙营养对氟的骨骼毒性的影响及其作用机理。     

人骨髓间充质干细胞体外分化为肝细胞样细胞

目的 探讨人骨髓间充质干细胞(MSCs)的体外培养及特异性诱导为肝细胞样细胞的能力。方法 骨髓标本来源于健康志愿者的胸骨,年龄2～35岁,采用淋巴细胞分离液(密度1.077)分离人MSCs,并分别采用HGF、FGF4、HGF FGF4以及无生长因子四种处理因素体外诱导第三代人MSC向肝细胞样细胞分化。通过流式细胞术分析鉴定.MSCs的纯度,于诱导培养的0、7、14、21、28天时留取细胞检测CK18、AFP和白蛋白的表达情况,同时进行糖原染色验证细胞功能。结果 用淋巴细胞分离液分离出的人MSCs纯度可达90％,采用HGF、FGF4及HGF FGF4三种处理因素均可在体外诱导人MSCs特异分化为具有肝细胞样细胞表型和功能的细胞。结论 人MSCs能在体外扩增并定向诱导为肝细胞样细胞。     

氟对淋巴细胞毒性的研究近况

淋巴细胞是体内极为复杂的不均一细胞群体,它包括许多形态上相似而功能上不同的细胞亚群,从大的细胞群体来说,淋巴细胞可分为T、B、NK、K、N、D等细胞。在免疫应答过程中,淋巴细胞起着重要的作用,尤其是作为核心细胞的T、B细胞。机体内淋巴细胞数目、功能、结构的改变均可引起自身免疫功能的异常。氟对淋巴细胞具有一定的毒性作用,随着遗传、免疫等学科的发展,氟对淋巴细胞毒性的研究,在内容上不断扩展,在层次上不断深入。     

体外诱导人羊膜间充质干细胞分化为胰岛素分泌细胞

目的 探讨体外诱导人羊膜间充质干细胞(hAD-MSCs)向胰岛素分泌细胞分化潜能.方法 采用胰蛋白酶-胶原酶消化法分离提取hAD-MSCs,流式细胞术分析和免疫细胞化学染色行表型鉴定.取第3代按2.5× 106个/ml或5×105个/ml细胞密度接种6孔培养板或预置盖玻片的24孔培养板,在含10mmol/L尼克酰胺和N2补充物的无血清HG-DMEM培养基培养,未诱导组为含10％胎牛血清的LG-DMEM基础培养基.分别于体外诱导第7、14、21天采用免疫细胞化学法检测胰岛素和β2微球蛋白的表达,采用放射免疫法检测上清液中胰岛素含量,采用RT-PCR检测胰岛素mRNA和胰十二指肠同源异型盒因子1(PDX-1)mRNA的表达.结果 (1)hAD-MSCs高表达间充质干细胞表面标志CD29、CD44、CD73、CD166及波形蛋白;(2) hAD-MSCs诱导第7、14、21天胰岛素阳性细胞百分率分别为74.67％±1.53％、75.00％±1.00％、74.33％±1.53％,培养物上清液中胰岛素含量分别为(331.62±1.76)、(330.50±1.22)和(331.65±0.48) μIU/ml,各时点间比较无显著性差异(均P＞0.05),而未诱导组仍未见胰岛素阳性细胞;培养上清也未检测到胰岛素;(3) hAD-MSCs诱导前后均有PDX-1 mRNA和蛋白表达,胰岛素基因mRNA表达仅见于诱导组;(4) hAD-MSCs诱导组和未诱导组各时点均有β2微球蛋白表达,其阳性细胞百分率组间差异无显著性(均P＞0.05).结论 hAD-MSCs具有向胰岛素分泌细胞分化的能力,可能成为1型糖尿病细胞移植治疗的新的细胞供源.     

体外原代培养脐带基质间充质细胞和人皮肤成纤维细胞

目的探讨体外原代培养脐带基质间充质细胞(UMC)和人皮肤成纤维细胞(HSF)的方法。方法用Ⅳ型胶原蛋白酶、Ⅰ型脱氧核糖核酸酶和0.25%胰蛋白酶消化法原代分离培养UMC细胞,用组织块贴壁法原代分离培养HSF细胞,镜下观察细胞的培养过程和生长状态。结果脐带组织分离培养第3天,有少量UMC贴壁生长,细胞膜周围有折光性,形态类似于成纤维细胞;皮肤组织块贴壁培养第7天,有HSF爬出,呈长梭形、不规则三角形。随着细胞培养时间延长,UMC和HSF数量逐渐增多,细胞生长状态良好。结论应用酶消化法和组织块贴壁法可成功分离培养出UMC和HSF。     

足细胞向间充质细胞转分化的研究

<正>肾脏纤维化是各种慢性肾脏病(CKD)的最终归宿和必然结局[1],其发生机制尚不清楚。近年研究显示,已分化上皮细胞向间充质细胞转分化(epithelial-mesenchymal transition,EMT),是合成细胞外基质(ECM)的成纤维细胞与肌成纤维细胞来源的重要途径。最初EMT概念源于胚胎发育和肿瘤转移[2],然而其在肾脏纤维化进展中也扮演了重要角色[3]。     

安替氟对高骨氟负荷大鼠的降氟解毒作用

为研究安替氟是否对高骨氟负荷大鼠具有明显的降氟解毒作用,给幼龄大鼠饮高氟水（含氟５０ｍｇ／Ｌ）８周后停止给氟,同时在饮水中添加安替氟（６ｇ／Ｌ）,连续４周。结果表明,安替氟可使氟致肾小管上皮细胞损伤修复以及骨、牙氟负荷下降过程加速,尿氟排出也呈增加趋势,但其机理尚不清楚。     

Effect of fluoride on human dental pulp cells in vitro

Human dental pulp cells were cultured in fluoride containing medium of various concentrations (0, 1, 2, 5, 10, 20, 25, 30, 40, 50, 60 and 80 ppm) in order to study the biological effect on the cells' proliferation and alkaline phosphatase (ALP) activities. It was found that fluoride at 5 ppm concentration significantly stimulated cell proliferation and ALP activity between 24 and 48 hours after exposure whereas at higher concentrations (40 - 80 ppm), fluoride significantly inhibited cell growth and ALP activity after 48 hours (Student's t test). The maximum effect was around 80 ppm. These observations suggest that fluoride, if used at a low concentration, may be a useful therapeutic agent for the treatment of pulpal disease by means of stimulating the proliferation and differentiation of dental pulp cells. At higher concentrations, it will have negative effects on this kind of cell.     

用单细胞凝胶电泳观察氟砷单独及联合对淋巴细胞DNA损伤

目的 观察氟、砷单独及联合作用对正常人淋巴细胞DNA的损伤作用及特点。方法 采用单细胞凝胶电泳（SCGE）实验，观察不同剂量氟、砷单独及联合应用对正常人淋巴细胞DNA的损伤。结果 人淋巴细胞在浓度为0．1、0．5μmol／L的NaAsO2及浓度为10、50μmol／L的NaF染毒24h后，均引起明显的DNA泳动（彗星尾）并呈现明显的剂量-效应关系；氟砷联合作用淋巴细胞，在0．5μmol／L NaAsO2＋50μmol／L NaF的剂量下，细胞DNA的损伤呈现出协同作用（P〈0．01）。结论 NaAsO2与NaF均可引起DNA损伤；低剂量NaAsO2与NaF联合作用时，则呈现协同作用。     

氟对大鼠培养心肌细胞的毒性及锌锰钼的拮抗作用

采用ＳＤ大鼠乳鼠心肌细胞进行培养、培养基中加氟（２６ｍｇＦ－／Ｌ），３０分钟后细胞搏动加速，而后停搏，细胞比活率显著下降，细胞（５１）Ｃｒ释放率持续显著性升高，细胞Ｃａ（２＋）、Ｎａ＋含量增加，Ｍｇ（２＋）、Ｋ＋降低。氟化培养基中添加锌、锰、钼（醋酸锌２０ｍｇ＋氯化锰０．５ｍｇ＋钼酸铵１３ｍｇ／Ｌ）可使上述氟毒作用明显减弱，并可使培养基中的Ｆ－明显减少。     

Pentamidine-induced beta cell toxicity is not preventable by high glucose

The incidence of beta cell damage attributable to pentamidine treatment of pneumocystis pneumonia is increasing in frequency because of the AIDS epidemic. We carried out in vitro studies in perfused rat islets using insulin secretion as an index of beta cell damage to study the effects of pentamidine and to test whether glucose can prevent toxicity in this physiologic model. Isolated islets were cultured for 16-18 hours of static incubation, in a culture medium containing 100 mg/dl glucose, with or without pentamidine (10(-6) M, a therapeutic concentration). Islets were then perfused with media containing 60 mg/dl followed by 300 mg/dl glucose concentrations to study the insulin secretory response. Incubation of islets with pentamidine was associated with subsequent basal hypersecretion of insulin (0.40 +/- 0.05 microU/islet .5 minute vs. 0.18 +/- 0.04 microU/islet .5 minute, p less than .005), and an insulin secretory response to glucose which was completely abolished (0.05 +/- 0.04 microU/islet .5 minute versus 1.12 +/- 0.02 microU/islet .5 minute, p less than .005). To determine whether glucose may protect against the effects of pentamidine, islets were then exposed to high glucose concentrations during simultaneous incubation with pentamidine. Coincubation with high glucose did not prevent these insulin secretory defects. A more extended culture of pentamidine-treated islets in the absence of pentamidine and at a glucose concentration of 100 mg/dl did not result in any recovery of insulin secretion. We conclude that pentamidine-induced beta cell damage is irreversible, not preventable by incubation with high glucose concentrations, and may therefore result from a mechanism different to that of alloxan.     

Intermittent high glucose enhances cell growth and collagen synthesis in cultured human tubulointerstitial cells

Aims/hypothesis. We investigated the effects of constant and intermittently increased glucose concentrations on human proximal tubule cells and cortical fibroblasts in primary culture. Methods. Cells were grown to confluence and then exposed for 4 days to 6.1 mmol/l d-glucose (normal), 25 mmol/l d-glucose (high), or 6.1 mmol/l alternating with 25 mmol/l d-glucose on a daily basis. Results. In proximal tubular cells, exposure to high glucose caused an 11 % increase in thymidine uptake (p < 0.05), a 230 % increase in secretion of transforming growth factor beta 1 (TGF-β1; p < 0.05) and a 393 % increase in platelet derived growth factor. Intermittent exposure to high glucose caused thymidine uptake to further increase by 42 % (p < 0.01) and TGF-β1 secretion by 352 % (p < 0.01) but no additional increase in platelet-derived growth factor secretion was observed. Cellular protein content increased by 27 % (p < 0.05) and collagen synthesis by 29 % (p < 0.05), changes that were not observed in cells constantly exposed to high glucose. In cortical fibroblasts constant exposure to high glucose caused a 35 % increase in thymidine uptake (p < 0.01). Intermittently high glucose increased thymidine incorporation a further 58 % (p < 0.001), collagen synthesis by 65 % (p < 0.01) and insulin-like growth factor binding protein 3 secretion by 216 % (p < 0.01). Conclusion/interpretation. In cultured human tubulointerstitial cells, increased glucose concentrations change cell growth, collagen synthesis and cytokine secretion. These effects are enhanced following intermittent exposure to high glucose, indicating that short lived excursions in glycaemic control have important pathological effects on the human tubulointerstitium. [Diabetologia (1999) 42: 1113–1119] Received: 18 January 1999 and in revised form: 3 March 1999     

煤烟污染型地方性氟病病区血清氟尿氟氟斑牙及氟骨症相关性研究

将煤烟污染型地方性氟病病区人群血清氟值，８～１２岁儿童即时尿尿氟值，８～１２岁儿童氟斑牙率、氟斑牙指数及成人氟骨症率作比较和相关性分析，发现儿童尿氟值与氟斑牙指数、氟斑牙率及氟骨症率之间有极好的线性关系。氟斑牙指数较单纯氟斑牙率更能客观地反映病情。建议：１．应将８～１２岁儿童尿氟值作为地方性氟中毒病区划分与病情监测的主要指标；２．应将氟斑牙率与氟斑牙指数结合应用；３．在煤烟污染型地氟病区，应设“特重病区”。     

Interleukin 6 is expressed in high levels in psoriatic skin and stimulates proliferation of cultured human keratinocytes.

Psoriasis is a common papulosquamous skin disease. The histopathology is characterized by epidermal hyperplasia and inflammation. Recent studies suggest that keratinocyte proliferation and inflammation in psoriasis are manifestations of the same underlying pathological process. Interleukin 6 (IL-6), a cytokine that is a major mediator of the host response to tissue injury and infection, is produced by both keratinocytes and leukocytes in culture. IL-6 expression was studied in psoriatic plaques by immunoperoxidase staining with two different polyclonal anti-recombinant IL-6 antisera and by in situ nucleic acid hybridization with IL-6 cRNA probes. Epidermal and dermal cells in active psoriatic plaques from 35 psoriasis patients stained heavily for IL-6 as compared with nonlesional skin and with plaques after treatment with antimetabolic and antiinflammatory agents. Absorption of the anti-recombinant IL-6 antisera with purified fibroblast-derived IL-6 or with recombinant IL-6, but not bovine serum albumin, removed the immunostaining. Increased levels of IL-6 were detected in the plasma of patients with active psoriasis (mean 3 ng/ml) by using two different bioassays. IL-6 production by proliferating keratinocytes was suggested by IL-6-specific immunostaining in cultured normal and psoriatic keratinocytes and by the detection of mRNA specific for IL-6 in psoriatic epidermis by in situ hybridization. IL-6 stimulated the proliferation of cultured, normal human keratinocytes as assessed by two different assays. Thus, IL-6 could directly contribute to the epidermal hyperplasia seen in psoriatic epithelium as well as affect the function of dermal inflammatory cells.     

High-density lipoprotein increases intracellular calcium levels by releasing calcium from internal stores in human endothelial cells

Elevated levels of high-density lipoproteins (HDL) appear to delay or prevent the development of atherosclerosis. The intracellular signaling mechanisms activated by HDL in vascular cells are currently under active investigation. In this study the effects of HDL on endothelial intracellular Ca levels (EC Ca(i)) are investigated. We show that HDL, like low density lipoproteins (LDL), increases EC Ca(i) in a dose-dependent fashion by releasing Ca from internal stores. Neither apolipoprotein A-I (apo A-I) nor apolipoprotein A-II (apo A-II) was responsible for the increase in EC Ca(i). HDL appeared to release Ca from the same internal stores as did LDL, since preincubation of EC with LDL prevented subsequent responses to HDL but not to the vasodilator ATP. In addition, preincubation of EC with pertussis toxin, an inhibitor of specific G proteins, as well as U73122, an inhibitor of phospholipase C, prevented a rise in EC Ca(i) in response to HDL. These findings suggest that HDL, like LDL, can modulate EC Ca(i) and that this occurs via a pertussis toxin-sensitive G protein-mediated pathway which involves phospholipase C.