钠依赖二羧酸转运蛋白在IgA肾病患者肾组织表达的研究

目的 研究人钠依赖二羧酸转运蛋白(human Na~+/dicarboxylate cotransporter,NaDC)在IgA肾病患者肾组织内表达的变化,探讨其在IgA肾病进展过程中的作用。方法 34例IgA肾病肾活检标本依据病理改变程度分为5级,同时对肾小管间质病变进行半定量分析。应用免疫组织化学技术观察肾组织内NaDC1和NaDC3的表达变化,并与临床指标进行相关分析。结果 随着IgA肾病病理改变程度的加重,肾小管间质病变亦加重。Ⅳ和Ⅴ级病变患者的24h尿蛋白定量、血肌酐和尿NAG酶均显著升高,尿渗透浓度显著下降(P<0.05)。NaDC1表达于近端肾小管上皮细胞的刷状缘上,与Ⅰ～Ⅲ级病例相比,Ⅳ和Ⅴ级病例中的NaDC1的表达减少,其中以Ⅴ级表达最少(P<0.05)。NaDC3表达于近端肾小管上皮细胞的基底侧膜上,与Ⅰ～Ⅱ级病例相比,Ⅱ～Ⅳ级病例中的NaDC3的表达增多,在Ⅴ级病例中,其表达显著减少(P<0.05)。肾小管NaDC1表达与尿NAG酶呈负相关(r=-0.627,P<0.05)。结论 钠依赖二羧酸转运蛋白的表达变化在IgA肾病进展过程中发挥重要的作用。     

Effect of Postnatal Exposure to a PCB Mixture in Monkeys on Multiple Fixed Interval–Fixed Ratio Performance

Behavioral impairment as a consequence of PCB exposure beginning in utero has been reported in both humans and animals. The present study assessed the behavioral consequences of postnatal exposure to PCBs. Male monkeys (Macaca fascicularis) were dosed from birth to 20 weeks of age with 7.5 μg/kg/day of a PCB mixture representative of the PCBs typically found in human breast milk (eight monkeys) or vehicle (four monkeys). At 4 years of age, performance under a multiple fixed interval (FI)-fixed ratio (FR) schedule of reinforcement was assessed. The FI component was more sensitive to disruption as a result of PCB exposure than was the FR component. PCB-exposed monkeys displayed shorter mean interresponse times (IRTs) than controls, particularly during the earlier sessions of the experiment. Similarly, the increase in pause time characteristic of the acquisition of typical FI performance emerged more slowly across sessions in the PCB-treated group. However, the number of short IRTs (less than 5 s) remained greater in the treated group compared to controls over the 48-session duration of the experiment. On the FR component, control monkeys decreases the mean pause time across sessions whereas the PCB-treated group did not; there were no differences between groups for absolute value of average IRT or pause time. The results of this study extend previous research in this cohort of monkeys, and provide further evidence that PCB exposure limited to the early postnatal period and resulting in environmentally relevant body burdens produces long-term behavioral effects.     

An improved algorithm for the numerical simulation of cyclic voltammetric curves affected by the ohmic potential drops and its application to the kinetics of bis(biphenyl)chromium(I) electroreduction

Previously published algorithms for the modeling of cyclic voltammetric curves affected by ohmic potential drops, in terms of the classical explicit finite differences method, are discussed briefly. A fast and efficient numerical procedure suitable for such simulations is described. This approach exhibits high numerical stability for both high scan rates and large uncompensated ohmic resistances. The procedure is based on the calculation of the faradaic current as a root of the non-linear equation, with a simultaneous calculation of the capacitive current. Comparison of the cyclic voltammograms obtained using this method with those calculated using alternative published procedures proves its validity. For comparison with the experimental data, the cyclic voltammetric response for the reduction of bis(biphenyl)chromium(I) tetraphenylborate in N,N-dimethylformamide is shown and the kinetic parameters of this process are fitted. Compared to earlier modelings, they show better concordance with the results of studies at microelectrodes. In conjunction with earlier successful applications of the analogous numerical procedure to the realistic modeling of electrochemical oscillations and multistability at a constant external voltage, the algorithm presented appears to be one of the most applicable methods of calculation of the electrochemical responses affected by the ohmic potential drops.     

Cross-reaction patterns in patients with contact allergy to simple methylol phenols

The low-molecular-weight phenols 2-methylol phenol (2-MP), 4-methylol phenol (4-MP), 2,4,6-trimethylol phenol (2,4,6-MP), 3-methylol phenol (3-MP), 2,4-dimethylol phenol (2,4-MP), and 2,6-dimethylol phenol (2,6-MP) are contact sensitizers in resins leased on phenol and formaldehyde (P-F-R). Other chemically related low-molecular-weight phenols are common in the environment. In patients hypersensitive to P-F-R and MPs, it is for diagnostic, therapeutic and preventive reasons necessary to know their cross-reaction patterns, which this study was therefore designed to investigate. In patients with contact allergy to a P-F-R and at least 1 MP, additional patch testing was performed with 6 MPs and 13 chemically related compounds. The 19 substances were tested at equimolar concentrations and in serial dilutions. Investigations by high-performance liquid chromatography were carried out to exclude contamination as the cause of the patch test reactions. Probable cross-reacting substances were o-cresol, p-cresol, salicylaldehyde, 2.4-dimethyl phenol, and 2.6-dimetrwl phenol.     

大鼠体外肝细胞集落的建立及生长调控研究

目的研究建立体外培养肝细胞集落的关键条件,探讨肝细胞克隆生长的调控机制。方法采用原位预灌流和胶原酶循环灌流分离肝细胞,观察在化学限定培养条件下,肝细胞生长素(HPN)、二甲亚砜(DMSO)及尼克酰胺(NA)对肝细胞DNA合成、有丝分裂象、光镜形态和电镜超微结构的影响。结果肝细胞培养时间进程显示:10 mmol/L NA显著协同HPN促进肝细胞3H-TdR掺入作用,在60和84 h出现2个DNA合成峰;2% DMSO抑制3H-TdR掺入,但在NA共同作用下,肝细胞在132 h表现为DNA合成峰。有丝分裂象显示:HPN NA DMSO培养72 h时肝细胞为正常二级分裂,168 h后仍保持相当的有丝分裂活性。光镜下形态及电镜超微结构观察到培养28 d的肝细胞克隆生长特征及增殖潜在性。结论NA及DMSO加入-移除方案可交叉控制HPN作用的肝细胞增殖,所构建的肝细胞克隆生长系统可用于人肝细胞代谢、诱变、细胞中毒及生物转化等研究,并为实施体外克隆肝细胞治疗肝衰竭及遗传性肝疾病提供实验依据。     

Differential effects of dimethyl sulfoxide on nicotinic acetylcholine receptors from mouse muscle and Torpedo electrocytes

The present study examined the effects of 0.1% dimethyl sulfoxide (DMSO) on nicotinic acetylcholine receptors (nAChR) from mouse muscle and Torpedo californica electrocytes. Receptors were expressed in Xenopus laevis oocytes and studied with voltage-clamp. When applied simultaneously with acetylcholine, DMSO did not inhibit current amplitude of either receptor. Preincubation with DMSO for 1 min reduced current amplitude by approximately 50% from oocytes expressing electrocyte receptor. Preincubation did not affect the muscle receptor. With electric organ membranes, 0.1% DMSO did not block either [-¹²⁵I]bungarotoxin binding to the nAChR agonist site or [³H]phencyclidine binding to its high affinity site on resting or desensitized receptor. These data suggest that DMSO might be affecting the electrocyte receptor through a second messenger system.     

二甲基亚砜对小鼠脑缺血的影响

目的研究二甲基亚砜(DMSO)对小鼠脑缺血的影响,并初步探讨其机制.方法应用小鼠断头张口喘气模型观察喘气时间的变化;离体大鼠血管平滑肌条记录等张收缩.结果DMSO使小鼠张口喘气时间明显延长,呈剂量依赖性,同时DMSO呈浓度依赖性地松弛去氧肾上腺素预收缩的离体兔胸主动脉螺旋条.结论DM-SO具有一定的抗脑缺血作用,其作用机制可能涉及其舒血管作用,而增加脑血流量.     

低亲和力钠依赖二羧基转运蛋白随增龄表达变化的研究

目的 研究大鼠及人类肾脏低亲和力钠依赖(Na~+/)二羧基转运蛋白(NaDC1)随增龄的表达变化规律并探讨其在肾脏衰老变化中的意义。方法 采用Northern杂交、Western印迹及免疫组化等方法对大鼠出生后1d、7d、1个月、3个月、12个月、24个月及少年、中青年、老年正常人肾脏 NaDC1的表达变化。结果 大鼠NaDC1 mRNA表达呈现随肾组织发育成熟表达逐渐增强,1个月达高峰,后随增龄表达下降的趋势(P<0.05)。Western印迹显示NaDC1蛋白随鼠龄增高表达逐渐增强,3个月达高峰,后表达渐降的趋势。免疫组化结果显示大鼠及人类肾组织NaDC1分别表达于近端小管刷状缘,大鼠生后1d表达最弱,后表达渐强,到3个月达高峰(5.30±1.52比1.40±0.43,P<0.01),后呈现渐降的趋势(P<0.05)。人类肾组织NaDC1表达呈现随增龄渐降的趋势。结论 大鼠及人肾组织进入衰老时,NaDC1 mRNA及蛋白表达均呈现下降的趋势,可作为对肾脏衰老观察的指标之一。     

Umbilical cord blood progeny cells that retain a CD34+ phenotype after ex vivo expansion have less engraftment potential than unexpanded CD34+ cells

BACKGROUND: Because of the limitation of cell numbers associated with cord blood harvests, there is a need to determine the efficacy of using ex vivo-expanded cord blood cells in a transplantation setting. In this study, limiting-dilution analysis was used in nonobese diabetic mice with severe combined immunodeficiency (NOD/SCID) to compare the engraftment potential of progeny cells expressing the CD34+ phenotype after expansion with that of uncultured CD34+ cells. STUDY DESIGN AND METHODS: Cord blood CD34+ cells were cultured in Iscove's modified Dulbecco medium supplemented with 10-percent fetal calf serum (FCS) and IL-6, SCF, megakaryocyte growth and development factor, and Flt3 ligand. The resulting ex vivo-expanded products were assessed for total numbers of nucleated cells, CD34+ cells, and CFUs and long-term culture-initiating cell activity. The engraftment potentials of cultured progeny CD34+ cells and uncultured CD34+ cells were determined by using NOD/SCID mice. RESULTS: After 14 days of culture, total nucleated cell counts increased over input values by 180 +/- 59-fold, CD34+ cell numbers by 44 +/- 13-fold, CFU activity by 23 +/- 5-fold, and long-term culture-initiating cell activity by 20 +/- 6-fold (mean +/- SD; n = 6). The frequency of SCID-repopulating cells (SRC) in mice transplanted with uncultured products was 1 per 20,000 CD34+ cells (95% CI, 1:10,000-1:38,000) and that in mice receiving ex vivo-expanded products was 1 per 418,000 progeny CD34+ cells (95% CI, 1:158,000-1:1,100,000). Taken together, these data indicated that, after 2 weeks of culture, there was a modest twofold increase in the total number of SRCs. However, the levels of human CD45 cell engraftment in NOD/SCID recipients of progeny CD34+ cells were significantly lower than those in mice receiving equivalent numbers of uncultured CD34+ cells (p<0.05). CONCLUSION: Umbilical cord blood progeny cells retaining a CD34+ phenotype after ex vivo expansion have less engraftment potential than do unexpanded CD34+ cells.