多细胞株微量培养法在病毒性脑炎、脑膜炎患儿病原学检测的应用研究

目的探讨多细胞株微量培养法在病毒性脑炎、脑膜炎病原学检测中的应用价值。方法将脑脊液(CSF)标本过滤除菌后分别接种于含有青霉素和链霉素微量细胞培养板单层细胞上,每份标本平行接种8株细胞:MA104、MDCK、HEL、HEK293、Vero、Hep-2、Hela和BHK-21。静置培养,获得稳定的病毒株。以肠道病毒(EV)组合血清鉴定引起病毒性脑炎、脑膜炎的常见病毒类型。结果 126份病毒性脑炎、脑膜炎患儿CSF标本82份分离到病毒,阳性率63.0%,其中MA104阳性率为57.1%,MDCK阳性率为19.8%,HEL阳性率为11.9%,HEK阳性率为7.1%,Vero阳性率为6.3%,Hep-2阳性率为4.8%,Hela阳性率为4.0%,BHK-21阳性率为2.4%。病变细胞经血清学鉴定,78例鉴定出病毒株,鉴定率为92.8%,这些病毒中EV所占比例较高,为69.2%;ADV占11.5%,HSV-Ⅰ占5.1%,HSV-Ⅱ占6.4%;CMV占5.1%,INF占2.6%。结论 MA104细胞是分离CSF中病毒较敏感的细胞,可以作CSF中病原分离的首选细胞;联合多株细胞可提高细胞病变检出率。多株细胞微孔板培养法分离CSF病毒具有推广应用价值。

Effects of Echinacea purpurea Polysaccharide on IEC-6 Cell Proliferation

[Objective] This study was conducted to investigate the effects of Echi-nacea purpurea polysaccharides （EPS） on proliferation of rat intestinal epithelial cel IEC-6. [Method] The proliferation rate of IEC-6 cel s cultured in EPS at different concentrations and for different time was measured by MTT assay and analyzed by statistic methods. [Result] The proliferation rate of IEC-6 cel s cultured in EPS at al the concentrations and for different time was improved by different extents in com-parison with the control. In detail, 50 and 200 μg/ml EPS greatly improved the IEC-6 cel proliferation after 24 h of culture; then, the cel proliferation rate in the two treatments increased from 24 to 48 h, and declined from 48 to 72 h. The cel pro-liferation was also significantly improved by culturing in 100 μg/ml EPS for 72 h and in 500 μg/ml EPS for 48 h. After 48 h of culture, the proliferation rate of IEC-6 cel increased in a EPS dose-dependent manner. [Conclusion] EPS can promote IEC-6 cel proliferation, and thus improve the intestinal mucosal absorption and immune function of rat.

Down-regulation of extracellular signal-regulated kinase 1/2 activity in P-glycoprotein-mediated multidrug resistant hepatocellular carcinoma cells

AIM： To study the expression and phosphorylation of extracellular signal-regulated kinase （ERK） i and ERK2 in multidrug resistant （MDR） hepatocellular carcinoma （HCC） cells.METHODS： MDR HCC cell lines, HepG2/adriamycin （ADM） and SMMC7721/ADM, were developed by exposing parental cells to stepwise increasing concentrations of ADM. MTT assay was used to determine drug sensitivity. Flow cytometry was employed to analyze cell cycle distribution and measure cell P-glycoprotein （P-gp） and multidrug resistant protein 1 （MRP1） expression levels. ERK1 and ERK2 mRNA expression lev-ls were measured by quantitative real-time PCR （QRTPCR）. Expression and phosphorylation of ERK1 and ERK2 were analyzed by Western blot.RESULTS： MTT assay showed that HepG2/ADM andSMMC7721/ADM were resistant not only to ADM, but also to multiple anticancer drugs. The P-gp expression was over 10-fold higher in HepG2/ADM cells than in HepG2 cells （8.92% ±0.22% vs 0.88% ± 0.05%, P 〈 0.001） and over 4-fold higher in SMMC7721/ADM cells than in SMMC7721 cells （7.37% ± 0.26% vs 1.74% ± 0.25%, P 〈 0.001）. However, the MRP1 expression was not significantly higher in HepG2/ADM and SMMC7721/ADM cells than in parental cells. In addition, the percentage of MDR HepG2/ADM and SMMC7721/ADM cells was significantly decreased in the G0/G1 phase and increased in the the S phase or G2/M phase. QRT-PCR analysis demonstrated that the ERK1 and ERK2 mRNA expression increased apparently in HepG2/ADM cells and decreased significantly in SMMC7721/ADM cells. Compared with the expression of parental cells, ERK1 and ERK2 protein expressions were markedly decreased in SMMC7721/ADM cells. However, ERK2 protein expression was markedly increased while ERK1 protein expression had no significant change in HepG2/ADM cells. Phosphorylation of ERK1 and ERK2 was markedly decreased in both HepG2/ADM and SMMC7721/ADM MDR cells.CONCLUSION： ERK1 and ERK2 activities are downregulated in P-gp-mediated MDR HCC cells. ERK1 or ERK2 might be a potential drug target for circumventing MDR HCC cells,

A novel myeloma cell line identified for multidrug resistant study

Objective:To find out how to overcome resistance during multiple myeloma(MM) treatment through establishing a multidrug resistant human multiple myeloma cell line and investigating its biological features.Methods:The parent cell line MOLP-2 was exposed to different concentrations of melphalan and a melphalan-resistant cell line MOLP-2/R was identified by continuous stepwise selection.The cell morphology and growth curves were examined.Protein levels of P-gp, MRP and FANCD2 monoubiquitination were checked by Western blotting.The IC50 of melphalan and resistance index(RI) were detected by MTT assay.Results:A melphalan-resistant cell line MOLP-2/R was finally identified.The RI of MOLP-2/R cells to melphalan was 6.03.Besides melphalan it was cross resistant to other chemotherapeutic agents, including ADM, CTX, DDP and VP-16.The multiplication time was postponed(P < 0.05).Studies showed that FANCD2 protein monoubiquitination was enhanced, but the levels of P-gp and MRP expressions in the MOLP-2/R cells were similar with the parent cells.Conclusion:MOLP-2/R cell line may serve as an ideal model for exploring the mechanism of MDR.Over-expression of FANCD2 protein monoubiquitination might contribute to acquired drug resistance in MOLP-2/R cell line.

The difference between multi-drug resistant cell line A549/Gem and its parental cell A549

Objective:To discuss the difference between multi-drug resistant cell line A549/Gem and its parental cell A549 on the basis of establishment of human gemcitabine-resistant cell line A549/Gem so as to elaborate the possible mechanisms of gemcitabine resistance.Methods:Human gemcitabine-resistant non-small cell lung cancer cell line A549/Gem was estab-lished by the method of repeated clinical serous peak concentration plus gradually increasing concentration of gemcitabine from its parental cell human lung adenocarcinoma cell line A549 which was sensitive to gemcitabine.During the course of inducement,we had monitored their morphology,checked their resistance indexes and resistant pedigree by MTT method,gathered their growth curves and calculated their doubling time,examined their DNA contents and cell cycles by FCM;at the same time,we had measured their expressions of P53,EGFR,Cerb-B-2,PTEN,PCNA,c-myc,VEGF,MDR-1,Bcl-2,nm23,MMP-9,TIMP-1,and CD44v6 proteins via immunocytochemistry staining,RRM1 and ERCC1 mRNA by real-time fluorescent quantitative-PCR.Results:The resistance index of A549/Gem' cells(the deputy of cells in the process of inducement) to gemcitabine was 163.228,and the cell line also exhibited cross-resistance to vinorelbine,taxotere,fluorouraci,etoposide and cisplatin,but kept sensitivity to paclitaxol and oxaliplatin.The doubling time of A549/Gem' was shorter and figures in G0-G1 phases were increased than A549 cells.Compared with A549 cells,A549/Gem' cells achieved EGFR and c-myc proteins expressions,nm23 protein expression enhanced,P53,Cerb-B-2 and Bcl-2 proteins expressions reduced,PTEN,PCNA and MDR-1 proteins expressions vanished,but those of MMP-9,VEGF,CD44v6 and TIMP-1 proteins changed trivially.Meanwhile,expressions of RRM1 and ERCC1 mRNA were augmented markedly.The resistance index of A549/Gem cells to gemcitabine was 129.783,and the cell line also held cross-resistance to vinorelbine,taxotere,etoposide,cisplatin and sensitivity to paclitaxol.But the resistance to fluorouracil and sensitivity to oxaliplatin vanished.And the expression of RRM1 and ERCC1 mRNA decreased visibly.The doubling time of A549/Gem cells was longer and figures in G0-G1 phases were decreased than A549/Gem' cells.In A549/Gem cells,expressions of P53,EGFR,PCNA and MDR-1 proteins was same to those of A549/Gem' cells.A549/Gem cells achieved TIMP-1 and PTEN proteins expressions,Cerb-B-2,MMP-9,c-myc and Bcl-2 proteins expressions enhanced,nm23 protein expressions vanished,but the expressions of VEGF and CD44v6 proteins changed trivially.Furthermore,Compared with its parental cell A549,A549/Gem cell was mixed with giant cells of different sizes and was larger and more irregular.Conclusion:The human gemcitabine-resistant non-small cell lung cancer cell line A549/Gem had achieved multi-drug resistance and great changes of biological characters compared with its parental cells A549.And these changes possibly participated in the formation of multidrug resistance.

Genotypic Assessment by RAPD Markers and Ultrastructural Characteristics of a NaCI-Tolerant Potato Cell Line

Salinity is a serious threat to agricultural production. Potato （Solanum tuberosum） is an important food crop characterised for having low to moderate salinity tolerance. Tissue cultures may be relevant to improve salt tolerance in potato through selection of salt-tolerant cell lines and subsequent regeneration of plants. In this work, the authors used the random amplified polymorphic DNA （RAPD） markers to investigate the occurrence of genetic polymorphism in a potato calli line tolerant to 150 mM NaCI. Out of 40 primers screened, eight generated polymorphic patterns that distinguished salt-tolerant line from the control. Although the macroscopic appearance was similar in both lines, ultrastructural study revealed alterations in salt-grown cells. These showed that plastids less differentiated with a lower number of grana had more and larger starch grains than control cells. In conclusion, RAPD analysis revealed that NaCl-adapted line is a somaclonal variant and the ultrastructural study showed changes essentially at the plastids.