溴氰菊酯对白纹伊蚊C6／36细胞株的杀伤作用及对其形态影响的研究

本文采用ＭＴＴ微量酶反应比色法，研究了溴氰菊酯对白纹伊蚊Ｃ６／３６细胞的杀伤作用、形态影响以及受损细胞的恢复。结果发现用溴氰菊酯处理２４ｈ后，对Ｃ６／３６细胞的半数毒性浓度（ＩＣ５０）为７４８８μｇ／ｍｌ，且毒性作用强度随着药物浓度增加而增强。溴氰菊酯浓度在２０μｇ／ｍｌ以上时可以诱发Ｃ６／３６细胞形态学改变，表现为细胞呈多形性、细胞间有间隙、胞质内充满颗粒，以后随药物浓度的升高，胞质出现空泡、染色质凝成粗大颗粒或无结构大块、大片细胞脱落、崩解、死亡。高浓度溴氰菊酯（１６０μｇ／ｍｌ）作用于Ｃ６／３６细胞，其受损细胞的恢复与作用时间有关，作用２４ｈ的细胞，在经历一段生长停滞后，可缓慢恢复，而作用４８ｈ的细胞，则不可逆转的死亡     

Ventilatory response to hypercapnia in sprint and long-distance swimmers

Summary Ventilatory response lines to carbon dioxide at rest were determined by the rebreathing method in 10 untrained subjects, 17 sprint swimmers, and 11 long-distance swimmers. It was found that the mean slope of the ventilatory response line of the swimmer was lower than that of the untrained group, and the mean slope of the long distance swimmer was lower as compared with the sprint swimmer, though these differences were statistically not significant. The differences in the hypercapnic drive between untrained subjects and swimmers obtained here is discussed in connection with their maximum oxygen uptake.     

5-氮杂-2'-脱氧胞苷对HepG2细胞RUNX3基因表达及细胞增殖的影响

目的探讨人肝癌细胞系HepG2经5-氮杂-2’-脱氧胞苷(5-Aza-2-’deoxycytid ine,5-Aza-CdR)处理后诱导高甲基化失活的RUNX3基因重新表达的可能性及对细胞生长的影响,寻找抗癌治疗的新靶点。方法RT-PCR检测抑癌基因RUNX3 mRNA的表达;MTT、集落形成实验观察细胞的生长活性;流式细胞术和透射电镜分析细胞周期及细胞凋亡的变化。结果肝癌细胞经不同浓度之5-Aza-CdR处理后,原无RUNX3 mRNA表达的细胞均检出基因重新表达,细胞生长速度出现不同程度减慢及细胞克隆形成率显著降低(P<0.01)。用药后肝癌细胞发生明显的S期阻滞,电镜显示肝癌细胞形态学改变。结论去甲基化制剂5-Aza-CdR能有效地激活肝癌细胞系HepG2因高甲基化所致RUNX3基因沉默的再转录,诱导该基因的表达,从而抑制肿瘤细胞生长。     

Pseudo dicentric chromosome (5;21): a rare example of maternal germline mosaicism

Karyotyping of a malformed male newborn revealed the unbalanced karyotype of 46,XY, psudic(5;21)(q12;p13), +5 resulting in trisomy for the short arm of chromosome 5 and partial trisomy for 5q. Both parents had normal karyotypes in their peripheral blood lymphocytes. A second pregnancy ended in a miscarriage at 16 weeks gestation, sonographically 12 weeks. Karyotyping of chorionic villi from the abortus revealed the same unbalanced karyotype that had been identified in the first child. Fluorescence in-situ hybridization analysis confirmed a trisomy 5p. Microsatellite marker analysis ruled out illegitimacy and proved the maternal origin of the trisomic section of chromosome 5. Extended chromosome analysis of 60 metaphase cells from maternal skin fibroblasts and 40 metaphase cells from lymphocytes did not reveal mosaicism for psudic(5;21). These findings suggest the presence of a maternal germline mosaicism.     

Epidermal growth factor and insulin short‐term increase hPepT1‐mediated glycylsarcosine uptake in Caco‐2 cells

Aims: Little is known about the physiological regulation of the human intestinal di/tri‐peptide transporter, hPepT1. In the present study we evaluated the effects of epidermal growth factor (EGF) and insulin on hPepT1‐mediated dipeptide uptake in the intestinal cell line Caco‐2. Methods: Caco‐2 cells were grown on filters for 23–27 days. Apical dipeptide uptake was measured using [¹⁴C]glycylsarcosine([¹⁴C]Gly‐Sar). HPepT1 mRNA levels were investigated using RT‐PCR, cytosolic pH was determined using the pH‐sensitive fluorescent probe BCECF. Results: Basolateral application of EGF increased [¹⁴C]Gly‐Sar uptake with an ED₅₀ value of 0.77 ± 0.25 ng mL^?1 (n = 3?6) and a maximal stimulation of 33 ± 2% (n = 3?6). Insulin stimulated [¹⁴C]Gly‐Sar uptake with an ED₅₀ value of 3.5 ± 2.0 ng mL^?1 (n = 3?6) and a maximal stimulation of approximately 18% (n = 3?6). Gly‐Sar uptake followed simple Michaelis‐Menten kinetics. K_m in control cells was 0.98 ± 0.11 mM (n = 8) and V_max was 1.86 ± 0.07 nmol cm^?2 min^?1 (n = 8). In monolayers treated with 200 ng mL^?1 of EGF, K_m was 1.11 ± 0.05 mM (n = 5) and V_max was 2.79 ± 0.05 nmol cm^?2 min^?1 (n = 5). In monolayers treated with 50 ng mL^?1 insulin, K_m was 1.03 ± 0.08 mM and V_max was 2.19 ± 0.06 nmol cm^?2 min^?1 (n = 5). Kinetic data thus indicates an increase in the number of active transporters, following stimulation. The incrased Gly‐Sar uptake was not accompanied by changes in hPepT1 mRNA, nor by measurable changes in cytosolic pH. Conclusions: Short‐term stimulation with EGF and insulin caused an increase in hPepT1‐mediated uptake of Gly‐Sar in Caco‐2 cell monolayers, which could not be accounted for by changes in hPepT1 mRNA or proton‐motive driving force.     

香烟尘粒对人脐静脉内皮EA.hy926细胞的损伤作用

目的:选用人脐静脉内皮EA.hy926细胞株作为研究对象,观察二甲基亚砜溶解的香烟尘粒(DSP)对人脐静脉内皮EA.hy926细胞生长的影响。方法:以(1、2、4、8)mL/L剂量DSP作量效实验,小剂量DSP(2mL/L)作时效实验,采用MTT比色法和96孔板细胞蛋白测定方法来评价DSP对该细胞株增殖和活性的影响。透射电镜(TEM)观察不同处理因素作用后细胞超微结构变化。结果:DSP能抑制人脐静脉内皮EA.hy926细胞增殖(P<0.05),且对该细胞株具有明显毒性,它能减少细胞蛋白合成(P<0.05)、增加细胞死亡(主要为坏死),作用呈剂量和时间依赖。结论:DSP能损伤血管内皮细胞(VEC)。     

Characterization of the murine interleukin 5 receptor by using a monoclonal antibody

Murine interleukin 5 (IL-5), a lymphokine produced by helper T cells, is involved in the regulation of growth and differentiation of B cells and other hematopoietic cells. The receptor for IL-5 has been identified as two cross-linked complexes on T88-M cells (a murine IL-5-dependent early B cell line). In this study the IL-5 receptor was directly characterized by utilizing an immobilized IL-5 column and a rat monoclonal antibody, designated H7, directed against the IL-5 receptor. H7 completely inhibited specific binding of 35S-labeled IL-5 to T88-M cells, and bound to IL-5-responsive cells, e.g. T88-M, BCL1-B20 (a chronic B-cell leukemia), and MOPC104E (a myeloma), whereas H7 did not bind to IL-5-non-responsive cells, e.g. X5563 (a myeloma), FDC-P1 (an IL-3-dependent line), and MTH (an IL-2-dependent CTLL). H7 could barely bind to T88-M cells in the presence of IL-5, and immunoprecipitated a major band with an Mr of approximately 60 kd from the extract of surface-radioiodinated T88-M cells. The precipitation of this 60 kd molecule was inhibited by the addition of IL-5. Analysis with immobilized IL-5 also revealed that a 60 kd molecule bound specifically to IL-5-coupled beads compared with control beads. Furthermore, no additional molecule with a higher Mr that was recognized by H7 appeared under non-reducing, compared with reducing, conditions. The 60 kd molecule recognized by H7 could be digested with N-glycanase to yield a protein band of approximately 55 kd.(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of a multiplex PCR-based reverse line blot (mPCR/RLB) hybridisation assay for the rapid identification of bacterial pathogens.

The aim of this study was to develop a sensitive and reliable method for the molecular identification of pathogenic bacteria. A multiplex PCR-based reverse line blot (mPCR/RLB) hybridisation assay was developed and evaluated for the rapid identification of 24 systemic and respiratory bacterial pathogens in routine diagnosis. All species-specific probes designed for the RLB hybridised with amplified DNA only from the corresponding species. Sensitivity limits of the mPCR/RLB assay varied among the 24 target organisms from 0.05 pg to 0.5 ng of genomic DNA. The sensitivity of the assay was 2 x 10(2) CFU/mL for Streptococcus pneumoniae and 6 x 10(2) CFU/mL for Escherichia coli. The specificity of each probe was tested against 24 species. There were no cross-reactions among any of the 43 probes. The mPCR/RLB assay appeared to be a useful alternative tool for the molecular identification of common pathogens.     

一种高度敏感的改良的IL—1检测方法

采用CTLL-2检测IL-1诱导小鼠胸腺瘤细胞系EL_4产生IL-2活性,建立了一种间接检测IL-1的方法。通过对多种影响因素进行探讨,选择了较适的诱导血清浓度,细胞浓度,诱导时间和转移诱导上清稀释度,从而使检测IL-1的敏感性达10~(-3)～10~(-4)U/ml(2.5～25×10~(-4)Pg/ml,约为小鼠胸腺细胞检测方法的10~2～10~3倍),整个检测流程可在40小时内完成。若用CTLL-2和EL_4细胞同时培养的一步法检测,敏感性约为10~(-1)U/ml,但30小时内可完成检测。此法不受高浓度rHuTNF-α、rHuTNF-β、rHuIL-6干扰,IL-2、ConA、PHA、LPS和SEB对检测系统只有较弱的影响,但A23187可明显地干扰检测系统。因此,本方法可用于基础和临床研究过程中不同来源的IL-1生物学活性检测。     

THE ESTABLISHMENT OF THE NORMAL HUMAN FIBROBLAST CELL LINE AND A STUDY OF ITS BIOLOGICAL CHARACTERIZATION

用正常成人包皮组织建立NHF8细胞系在体外长期传代培养达400余天。细胞形态为成纤维样并呈规则的放射状生长。细胞培养于含有15％小牛血清的Ⅰ号培养液中并以1:2比例传代培养。细胞系的群体倍增肘间为26小时,其生长曲线呈“S”形。该细胞系染色体众数为46,自发姐妹染色单体交换率(SCE)为0.144/每染色体,紫外线(UV)诱发SCE率为0.143/每染色体。该细胞系经UV诱发的非合成期DNA修复合成(UDS)水平也是正常的。上述结果表明,NHF8细胞是具有正常DNA损伤修复功能的人二倍体细胞系,可以用于许多研究中作为正常对照细胞。此外,我们还利用该细胞系进行了体外细胞恶性转化及环境诱变物质检测等方面的工作。