中国对虾Penaeus Chinensis细胞学研究——中枢神经系统神经元细胞体显微观察

描述中国对虾中枢神经系统神经元细胞体的细胞学结构：神经元细胞体分布在神经节的皮质，每个神经元外都有神经胶质细胞和其突起形成的鞘包裹着，细胞体质膜内陷分枝形成胞管系；尼氏体在各神经节神经元细胞体中都呈细颗粒状均匀分布，其数量随生理状况而改变；内质网膜外表面附有少量核糖体，内质网池不规则，均匀分布在细胞质中；高尔基体呈孤状、圈状和Ｕ状；线粒体丰富，为圆形和短棒形，嵴不规则，缺少基粒；

The effect of STAT5 silenced by siRNA on proliferation,apoptosis and invasion of esophageal carcinoma cell line EC9706

Objective:The aim of the study was to explore the effect of STAT5 silenced by siRNA on proliferation,apoptosis and invasion of esophageal carcinoma cell line EC9706.Methods:The siRNA vectors aiming to STAT5 gene were constructed.STAT5 siRNA was transfected into EC9706 cells by Lipofectamine TM 2000.Changes of STAT5,Bcl-2 and Cyclin D1 were analyzed by Western blot and RT-PCR.Effect of STAT5 siRNA on EC9706 cells proliferation was determined by MTT.Effects of STAT5 siRNA on EC9706 cells cycle and apoptosis were detected by the flow cytometry.Boyden chamber was used to evaluate the invasion and metastasis capabilities of EC9706 cells.Results:The double strands oligonucleotide of siRNA aiming to STAT5 was successfully cloned into the pRNAT-U6.1 vector,and the target sequence was coincide with the design.RT-PCR and Western blotting detection demonstrated that the expression levels of STAT5,Bcl-2 and Cyclin D1 genes were obviously decreased in EC9706 cells transfected with STAT5 targeting siRNA expression vectors.STAT5 siRNA could suppress the proliferation of EC9706 cells.The proportions of S and G2/M periods frequency were significantly decreased (P < 0.05),and the proportion of G0/G1 period frequency was significantly increased (P < 0.05).The average amount of cells penetrating Matrigel was significantly decreased (P < 0.05).Silencing the STAT5 induced the apoptosis of esophageal carcinoma cell line EC9706 (P < 0.01).Conclusion:STAT5 silenced by siRNA of esophageal carcinoma cell line EC9706 could induce the apoptosis.And it could suppress the proliferation,invasion and metastasis of tumor cells.

Effects of angiopoietin-1 on attachment and metastasis of human gastric cancer cell line BGC-823

AIM： To evaluate the effects of angiopoietin-1 （Ang-1） on adhesion of gastric cancer cell line BGC-823 and expression of integrin β1, CD44V6, urokinase-type plasminogen activator （uPA） and matrix metalloproteinase-2 （MMP-2）. METHODS： BGC-823 cells were transfected transiently with adenovirus-Ang-1 （Ad-Ang-1）. Cells transfected transiently with adenovirus-green fluorescent protein （Ad-GFP） and untransfected cells were used as a negative and blank control group, respectively. The cell adhesion rate between cell and extracellular matrix （ECM） was determined by cell adhesion assay. To investigate whether Ang-1 could reinforce gastric carcinoma metastasis, we performed migration and invasion assays in BGC-823 cells. The mRNA and protein expression of integrin β1, CD44V6, uPA and MMP-2 were detected by reverse transcription polymerase chain reaction and Western blotting, respectively. The expression of integrin β1 and CD44V6 was measured by immunohistochemistry. RESULTS： BGC-823 cells were transfected successfully. The adhesion rate increased significantly in the Ad-Ang-1 group （P 〈 0.05）. The Ad-Ang-1-transfected group had a significant increase in migration and invasion compared with that of the mock-transfected and Ad-GFP groups. The mRNA and protein expression of integrin β1, CD44V6, uPA and MMP-2 in the Ad- Ang-1 group was higher than that in the Ad-GFP and blank control groups （P 〈 0.05）. Compared with mocktransfected and Ad-GFP groups, integrin 131 and CD44V6 expression intensity greatly increased （P 〈 0.05）. CONCLUSION： Transfection of Ang-1 into human gastric cancer cell line BGC-823 can significantly increase expression of integrin β1 and CD44V6, by which cell adhesion and metastasis to the ECM are promoted.

Different modes of renal proximal tubule regeneration in health and disease

Tissues are equipped with reasonable strategies for re-pair and regeneration and the renal proximal tubule （PT）is no exception. New information has become availableon the mode of PT regeneration in mammals. Unlikethe intestinal epithelium with a high rate of turnovermaintained by the stem cell system, the kidney has lowturnover under normal physiological conditions. The PTseems to be maintained physiologically by hyperplasia,a regenerating system with self-renewal of mature tu-bular cells. This mode of regeneration is advantageousfor effective replenishment of randomly isolated andeliminated tubular cells by self-renewal of adjacentcells. On the other hand, it has been suggested thatdedifferentiation of mature tubular cells plays a role inregeneration after acute kidney injury. Recent studiesemploying genetic labeling and DNA-labeling tech-niques have confrmed that the proliferation of preex-isting injured mature tubular cells contributes mainlyto PT regeneration in ischemic reperfusion injury. Thismode of regeneration is beneficial with regard to therapid reparation of focally injured tubules often inducedby ischemic reperfusion injury. What happens, howeverwhen the PT is homogeneously injured with almost noremaining surviving cells？ Is the PT equipped with another backup regeneration system, e.g., the stem cell system？ Is it possible that certain types of renal injuries evoke a stem cell response whereas others do not？ This review focuses on all three possible modes of tis-sue regeneration （compensatory hyperplasia, dediffer-entiation and stem cell system） in mammals and their involvement in PT regeneration in health and disease.

Genomic imbalances in esophageal carcinoma cell lines involve Wnt pathway genes

AIM： To identify molecular markers shared across South African esophageal squamous cell carcinoma （ESCC） cell lines using o/togenetics, fluorescence in situ hybridization （FISH） and single nucleotide polymorphism （SNP） array copy number analysis. METHODS： We used conventional cytogenetics, FISH, and multicolor FISH to characterize the chromosomal rearrangements of five ESCC cell lines established in South Africa. The whole genome copy number profile was established from 250K SNP arrays, and data was analyzed with the CNAT 4.0 and GISTIC software. tions involved the following chromosomal regions and genes： 11q13.3 （CCND1, FGF3, FGF4, FGF19, MYEOV）, 8q24.21（C-MYC, FAM84B）, 11q22.1-q22.3 （B[RC2, BIRC3）, 5p15.2 （CTNND2）, 3qll.2-q12.2 （MINA） and 18p11.32 （TYMS, YES1）. The significant deletions included 1p31.2-p31.1 （CTH, GADD45a, DIRAS3）, 2q22.1 （LRPIB）, 3p12.1-p14.2 （FHIT）, 4q22.1-q32.1 （CASP6, SMAD1）, 8p23.2-q11.1 （BNIP3L） and 18q21.1-q21.2 （SMAD4, DCC）. The 3p11.2 translocation breakpoint was shared across four cell lines, supporting a role for genes involved at this site, in particular, the EPHA3 gene which has previously been reported to be deleted in ESCC.CONCLUSION： The finding that a significant number of genes that were amplified （FGF3, FGF4, FGF19, CCND1 and C-MYC） or deleted （SFRP2 gene） are involved in the Wnt and fibroblast growth factor signaling pathways, suggests that these pathways may be activated in these cell lines.

Effect of Lentivirus-induced shRNA Silencing CXCR4 Gene on Proliferation and Apoptosis in Human Esophageal Carcinoma Cell Line Eca109

OBJECTIVE To discuss the application of the slow virus-induced short-hairpin RNA （vshRNA） to silence the expression of CXCR4 in EsCa cell lines Eca109, and observe the effect of silencing CXCR4 on the proliferation and apoptosis of Eca109 cells in vitro. METHODS The expression plasmid of vshRNA targeting CXCR4 was constructed, with a concurrent construction of negative vshRNA expression plasmid, and without targeting any known mRNA. Real-time quantitative PCR and Western blot assay were used to determine the change of CXCR4 expression in the post-transfected EsCa cell Eca109, and MTT assay was conducted to detect the change of proliferation in EsCa Eca109 cell after silencing the CXCR4. The .ow cytometry was used to detect the change of the cell cycle and apoptosis in the post-silenced EsCa Eca109 cell in di. erent groups. RESULTS The transfection rate was respectively （87.3 ± 1.2）% and （90.1 ± 1.4）% in the CXCR4- RNAi-LV （silent group） and NC-GFP-RNAi-LV （negative control group） cellular plasmids. The vshRNA interference resulted in a down-regulation of the CXCR4 gene mRNA and protein expressions in Eca109 cells. CXCL12 promoted the proliferation of EsCa cell lines Eca109. The speed of EsCa cell proliferation became slower in the silencing group than in the normal control （also the control） and the negative control groups （P 〈 0.05）. However, there was no significant difference in comparison of the proliferation speeds between the negative control and the normal control groups （P 〉 0.05）. In the silencing group, the proportion of the cells in phase G0/G1, phase S and phase G2/M was respectively （69.9 ± 5.0）%, （17.1 ± 2.5）% and （13.0 ± 7.4）%, and the apoptotic rate achieved （7.27 ± 0.50）%. In the normal control group, the proportion of the cells in phase G0/G1, S and G2/M was respectively （55.9 ± 4.6）%, （30.2 ± 3.9）% and （13.8 ± 1.4）%, and the apoptotic rate was （3.30 ± 0.70）%. In the negative control group, the proportion of cells in phase G0/G1, S and G2/M was respectively （52.7 ± 7.8）%, （25.3 ± 2.3）% and （21.9 ± 7.4）%, with an apoptotic rate of （4.03 ± 1.37）%. Compared with the normal control and negative control groups, there was an apparent growth of cells in the phase G0/G1 （P 〈 0.05）, and a greatly increased number of cells in phase S （P 〈 0.05） in the silencing group. There was no signi. cant di.erence in comparison of those between the normal control and negative control groups （P 〉 0.05）. The apoptotic rate was obviously higher in the cells of the silencing group than in the normal control and the negative control groups （P 〈 0.05）. There was no signi. cant di.erence in comparison of the apoptotic rate between the normal control and the negative control groups （P 〉 0.05）. CONCLUSION CXCR4-vshRNA can specifically and effectively inhibit CXCR4 expression of Eca109 cells. CXCR4-vshRNA can inhibit the proliferation and enhance the apoptosis rate of Eca109 cells through intervening the expression of CXCR4, suggesting that CXCL12/CXCR4 might have an important role in the progression of Escc Thisslow virus-induced shRNA can effectively silence the expression of CXCR4 gene in the EsCa cells; block up the biological e.ect of CXCL12/CXCR4 axle; and e.ectively inhibit the potency of proliferation in the EsCa cell line Eca109, thus advancing apoptosis. It suggests that the CXCL12/CXCR4 plays an important role in the progression of EsCa.

Fumagillin treatment of hepatocellular carcinoma in rats: An in vivo study of antiangiogenesis

AIM: To investigate the effect and possible mechanisms of antiangiogenesis therapy for HCC in rats.METHODS: Adult male LEW/SsN rats were divided into 3groups, 25 animals each. Group A was the control group.Groups B and C were given diethylnitrosamine, 5 mg/kg/d.In addition, group C rats received an intraperitoneal injection of fumagillin, 30 mg/(kg.d). Five animals in each group were killed at 6th, 12th, 18th, 20th and 24th wk to evaluate the development of HCC and metastasis. Weight of the rats, liver tumors, and number of organs involved by HCC were measured at each stage. We compared methionine aminopeptidase-2 (MetAP-2) mRNA, Bcl-2mRNA, telomerase mRNA, and telomerase activity at 24th wk in the liver tissue of group A rats and tumor tissue of HCC from group B and C rats.RESULTS: No HCC developed in group A, but tumors were present in group B and C rats by the 18th wk. At wk 20 and 24, the median liver weight in group B was 0.64 g (range:0.58-0.70 g) and 0.79 g (range: 0.70-0.90 g) (P = 0.04),and that in group C was 0.37 g (range: 0.35-0.42 g) and 0.39 g (range: 0.35-0.47 g) (P = 0.67). The liver weight in group C rats was significantly lower than that in group B rats (P = 0.009). At the same time, the median metastasis score (number of organ systems involved) was 3 (range2-3)in group B, and 1 (range 1-2) in group C, a significant difference between the groups (P = 0.007, 0.004). The levels of MetAP-2 mRNA were significantly higher in groups B and C than in group A (P = 0.025), and significantly higher in group C than in group B (P = 0.047). The level of Bcl-2 mRNA was significantly higher in group B than in group A (P = 0.024), but lower in group C than in group B, although not significantly (P = 0.072). Telomerase mRNA was significantly higher in group B than in group A (P = 0.025), but significantly lower in group C than in group B (P = 0.016). The same inter-group relationship was also true for telomerase activity (P = 0.025 and 0.046).CONCLUSION: Fumagillin effectively inhibits both liver tumor growth and metastasis in rats in vivo. A possible mechanism is fumagillin-induced inhibition of MetAP-2,which plays an essential role in endothelial cell proliferation.Inhibition of MetAP-2 also results in inhibition of Bcl-2and telomerase activity.

Activation of STAT3 signaling in human stomach adenocarcinoma drug-resistant cell line and its relationship with expression of vascular endothelial growth factor

AIM: To investigate the difference in activation of STAT3 signaling between two human stomach adenocarcinoma cell lines: 5-fluorouracil resistant cell line and its parental cell line, and to evaluate its relationship with the expression of vascular endothelial growth factor (VEGF). METHODS: Western blot and electrophoretic mobility shift assay (EMSA) were used to detect the expression of phospho-STAT3 protein and constitutive activation of STAT3 in two human stomach adenocarcinoma cell lines, 5-fluorouracil resistant cell line SGC7901/R and its parental cell line SGC7901, respectively. The mRNA expression of VEGF was analysed by semi-quantitative RT-PCR. The expressive intensity of VEGF protein was measured by immunocytochemistry. RESULTS: The expressions of phospho-STATS protein and constitutive activation of STAT3 between two human stomach adenocarcinoma cell lines were different. Compared with the parental cell line SGC7901, the STAT3DNA binding activity and the expressive intensity of phospho-STAT3 protein were lower in the drug-resistant cell line SGC7901/R. The expression levels of VEGF mRNA and its encoded protein were also decreased in drugresistant cell line. CONCLUSION: Over-expression of VEGF may be correlated with elevated STAT3 activation in parental cell line. Lower VEGF expression may be correlated with decreased STAT3 activation in resistant cell line, which may have resulted from negative feedback regulation of STAT signaling.

Effect of Coriolus Versicolor Polysaccharide-B on the Biological Characteristics of Human Esophageal Carcinoma Cell Line Eca109

Objective To investigate the effect of Coriolus versicolor polysaccharide-B （CVPs-B） on the biological characteristics of human esophageal carcinoma cell line Ecal09 in vitro. Methods The cells of experimental group （EG） were cultured in DMEM with 10% FCS and 150μg/mL CVPs-B, the cells of control group （CG） were cultured in DMEM with 10% FCS without CVPs-B. MTT reduction assay was performed to detect the effect of CVPs-B on the proliferation of Ecal09 cells after the compound was administrated in varying concentrations. The living conditions of the Ecal09 cells were determined using trypan blue exclusion. Then, cell growth curves were drawn. Flow cytometry was performed to detect the effect of CVPs-B on the apoptosis and cell cycle of Ecal09. Results In comparison with the CG, a marked decrease in the proliferation of Eca09 cells was observed in the EG, after incubation with CVPs-B. The survival rate of Eca09 cells decreased as the time of CVPs-B incubation prolonged. Comparing the cell cycles and apoptotic rates between the two groups, the proportions of cells in the G0/G1, S, and G2/M phases in the EG were found to be （68.4±3.7）%, （13.9±2.1）%, and （17.7±1.4）%, respectively, after 24 h incubation with CVPs-B. The cells had an apoptotic rate of （9.7±0.7）%. On the other hand, the proportions of the G0/G1, S, and G2/M cells of the CG were found to be （53.9±3.6）%, （26.6±2.8）%, and （19.5±2.3）%, respectively, with an apoptotic rate of （5.7±1.4）%. In comparison with the CG cells, significant cell growth in the G0/G1 phase was observed in the EG （P〈0.05）. Furthermore, a significant decrease in the number of cells in the S phase was observed （P〈0.05） in the EG. Conclusions CVPs-B can inhibit proliferation and enhance apoptosis of Ecal09 cells and may be useful in the treatment of esophageal carcinoma.

Inhibitory effects of transfected Bcl-XL antisense oligodeoxynucleotide to proliferation and growth in esophageal carcinoma cell line and human esophageal carcinoma xenograft of nude mice

Objective： The aim of our study was to investigate the biological effects of Bcl-XL antisense oligodeoxynucleotide （ASODN） transfected into cultured esophageal carcinoma cells and human esophageal carcinoma xenograft in nude mice. Methods： Cationic liposome-mediated ASODN was used to transfect esophageal carcinoma cells. RT-PCR, Western blot, MTT assay, flow cytometry, and in situ apoptosis cells detection （TUNEL detection） were used to systematically study the biological effects of transfected cells both in vitro and in vivo. Results： In this study, the results showed that the proliferation of esophageal carcinoma cells in ASODN group decreased significantly when compared with the control group （P 〈 0.05）, at 57.3% Bcl-XL mRNA inhibitory rate, and a significant decreasing of Bcl-XL protein expression, at the apoptosis rates of （31.1 ＋ 5.8）% and 35.0% by flow cytometry and TUNEL assay respectively （P 〈 0.01, when compared with control groups）. It also showed that the growth of human esophageal carcinoma in nude mice of ASODN group was significantly inhibited （P 〈 0.05）, together with a significant decreased expression level of Bcl-XL mRNA and protein, and an induced tumor cell apoptosis in nude mice. Conclusion： Our result indicates BcI-XL ASODN can effectively inhibit the proliferation of esophageal carcinoma cells in vitro and tumor growth in vivo. The suppression of Bcl-XL expression by ASODN may offer both a therapeutic approach and an important theoretic foundation for gene therapy against esophageal carcinoma.

A Stream Control Transmission Protocol Based OAM System of 3G Cellular Network

OAM (Operations, Administration and Maintenance) system is a very impo rtant component of 3G cellular network. In order to acquire overall managemen t, fast response and steady operation, an SCTP (Stream Control Transmission Prot ocol) based OAM, i.e., SOAM system was proposed. SOAM implements new characters of SCTP such as multi-stream, enforced SACK and heartbeat mechanism on its tran sport layer. These characters help SOAM decrease the message transmission delay and accelerate the link failure detection. Besides, a new component named SOAM agent was introduced to improve the operation efficiency of SOAM. The experim ental results prove the proposed SOAM system achieves better performance on sign aling transmission compared with conventional TCP based OAM system.

Improvement of Tunable Diode Laser Absorption System with a Novel Multipass Cell and Wavelet Transform

Combination of Tunable Diode Laser Absorption Spectroscopy(TDLAS)technique and multipass cell is an attractive approach for ultrahigh sensitive detection of trace gases.Theoretically,based on Beer-Lambert law,the longer optical path length and the larger gas absorption,the lower concentration gas could be detected.However,lower radiation intensity and inevitable etalon fringe resulted from multiple reflections would greatly weaken the Signal-to-Noise Ratio(SNR)and thus an expected ultrahigh sensitive detection system is difficult to achieve.In order to fully make use of the advantages of TDLAS and multipass cell,the base length and the total optical path length of the multipass cell are needed to be carefully balanced.Furthermore,the harmonic signals contaminated by various noises are processed with wavelet transform method.As a demonstration of this method,few low concentrations of gas CO in N2 are measured employing TDLAS technique and a novel sealed multipass cell with total optical length of 114 m.The detection limit is about 5×10-6(volume ratio),which is one order of magnitude better than earlier noise reduction.

Study on effect of BSO on esophageal cancer cell line TE-1

Objective: The aim of the study was to investigate the sensitizing effect of buthionine sulfoximine (BSO) and radiation on esophageal cancer cell line TE-1. Methods: Methyl thiazolyl tetrazolium (MTT) assay was used to observe the inhibition of BSO and radiation on cell proliferation, and to investigate the sensitizing effect of BSO on esophageal cancer cell line TE-1. Flow cytometry (FCM) was used to observe the effect of BSO and radiation on cell apoptosis and cycle. Reverse transcription polymerase chain reaction (RT-PCR) and Western blot were used to observe the effect of BSO on manganese superoxide dismutase (MnSOD) mRNA and protein expression. Results: BSO could inhibit the proliferation of TE-1 esophageal cancer cells, and had significant dose- and time-dependent radiosensitizing effects on TE-1 esophageal cancer cells. After the combined effects of BSO and radiation on TE-1 cells, the rate of apoptosis and G2/M phase proportion increased significantly, and MnSOD mRNA and protein expression decreased. Conclusion: BSO may reduce MnSOD mRNA and protein expression by affecting TE-1 cell cycle, thus inhibiting and inducing the apoptosis of esophageal cancer cells and enhancing the killing effect of the radiation on esophageal cancer cells.

The use of suicide gene systems in vascular cells in vitro

To investigate the efficiency of suicide gene systems on vascular cells, HSV-tk/GCV and EC-CD/5-FC systems were established on vascular endothelial cells in vitro by retroviral transduction. Both modified cell lines were highly sensitive to prodrugs, the IC50 for GCV was less than 0.4 μM, and IC50 for 5-FC was less than 75 μM,while the parental endothelial cells were insensitive even at the highest concentrations of prodrugs in this experiment. Mixed cellular assay showed that significant bystander effect was exhibited in modified endothelial cells.When only 10% or 30% of the mixed cells were tk positive and exposed to 20 μM GCV for 6 days, more than 60% or 90% of the whole population was killed. Similar result was also found in CD positive cells. These results indicated that both HSV-tk/GCV and EC-CD/5-FC systems could efficiently suppress endothelial cell growth in vitro.

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.

Membrane nanotubes:Novel communication between distant cells

The many kinds of cell structures involved in cell-cell communication include tight junction,adherens junction and gap junction,but almost all are between adjacent cells.Recently,a general and dynamic membrane tether,termed tunneling nanotubes or membrane nanotubes(MNTs),was discovered to be involved in communication between distant cells.By facilitating intercellular communication,MNTs contribute to many biological functions and pathologic changes in cells.Many works have revealed the structure,formation and functional properties of MNTs.However,as novel structures,further research is needed.

Stem cell lineage in body layer specialization and vascular patterning of rice root and leaf

Since the first appearance of vascular plants during evolution, the plant body has become specialized for adaption to land conditions. Much of our knowledge of plant body specialization and the origins of tissues from stem cells have been obtained from studies on the dicot Arabidopsis thaliana. However, less is known about plant body specialization in monocots, another important branch of angiosperms. In this study, we analyzed stem cell lineage and differentiation during development of the root and leaf of the monocot model plant rice(Oryza sativa). Our results showed that three body layers of rice are established from stem cells accompanied by progressively reduced pluripotency. Layer 1(L1) is a single-cell layer of epidermis; L2 is the cortex/endodermis in the root and the mesophyll in the leaf; and L3 is the site of vascular initiation. At least two common steps in vascular development are shared between rice root and leaf. The preprocambium divides to form the procambium and root pericycle or leaf outer sheath. The procambium further differentiates into the xylem, phloem and circumambient cells. We found that the outer sheath of leaf vascular bundles originates not only from the preprocambium of L3,but also from the mesophyll precursor cells of L2. In addition, WUSCHEL-RELATED HOMEOBOX(WOX)genes are expressed in not only the stem cell niche but also metaxylem precursor in rice. This pattern differs from that of homologs in Arabidopsis, suggesting that WOX functions have been recruited in different stem cells in dicots and monocots.

Growing role of CD40 ligand gene transfer therapy in the management of systemic malignancies besides hepatocellular carcinomas

The article ＂Cationic liposome-mediated transfection of CD40 ligand gene inhibits hepatic tumor growth of hepatocellular carcinoma in mice＂ [doi： 10. 1631/jzus.B0820178] by Jiang et al.（2009） in a recent issue of the Journal of Zhejiang University SCIENCE B was highly thought provoking. The authors have clearly demonstrated the efficacy of CD40 ligand gene therapy in inhibiting the growth of hepatocellular carcinomas. The findings of Jiang et al.（2009） are highly important as they further support and corroborate the rapidly expanding role of CD40 ligand gene therapy in the management of systemic malignancies besides hepatocellular carcinomas.

Thermo-flow characteristics and air flow field leading of the air-cooled condenser cell in a power plant

Special A-frame geometry of the air-cooled condenser cell and the complicated flow field at the exit of the axial flow fan bring on the air mal-distribution on the surface of the finned tube bundles and the deteriorated thermo-flow performances of a condenser cell. It is of benefit to the design and operation optimization of the direct dry cooling system in a power plant to investigate the thermo-flow characteristics of the condenser cell and propose the flow leading measures of cooling air. On the basis of the representative configuration of the air-cooled condenser cell in a 600 MW direct dry cooling power plant, the computa- tional models of the air side fluid and heat flows are built, in which the actual fan blade geometric details are considered. Various flow field leading ways of cooling air are presented and the thermo-flow characteristics in the A-frame condenser cell and through the finned tube bundles are compared. Results show that the flow field leading measures can result in the increased volumetric flow rate and heat rejection, thus bringing on the improved performance of the condenser cell. The improvement of thermo-flow oerformances depends upon the geometric details of the flow guiding device.

Transportation of dynamic biochemical signals in non-reversing oscillatory flows in blood vessels

Biological processes and behaviors of endothelial cells on the inner surfaces of blood vessels are regulated by the stimulation from biochemical signals contained in the blood.In this paper,the transportation of dynamic biochemical signals in non-reversing oscillatory flows in blood vessels is analyzed by numerically solving a nonlinear governing equation for the time-dependent Taylor-Aris dispersion.Results show that the nonlinear frequency-amplitude modulation of the transportation of biochemical signals is more(less) significant when the frequency of an oscillatory flow is close to(higher than) that of an oscillatory signal.Under steady flow,the transfer function for the signal transmission system is obtained,showing that the system is a low-pass filter.Lower inner radius or higher center-line velocity of a blood vessel increases the cutoff frequency of the transportation system.These results suggest the possibility and condition for the 'remote' transmission of low-frequency dynamic biochemical signals in pulsatile blood flows.