Mucins are high molecular weight glycoproteins that are synthesized by secretory epithelial cells as membrane bound or secreted products which play important roles in protecting and lubricating mucosa. Their quantitative and /or qualitative changes have a relationship to gastric cancers.

Various teaching methods can be applied comprehensively to the teaching of oral histopathology. The authors make a probe into the function and significance of flexible introduction of such means as enlightened approach to teaching,metaphorical teaching method,multimedia teaching method. The paper insists that these methods will bring many benefits in that they will help to promote students’autonomous learning,stimulate their thinking,cultivate their competence for observation and analysis,broaden their vision,and consequently improve the teaching quality.

In the process of pathology teaching,the teacher can apply various methodologies and techniques to form student-oriented situation,to raise their interest in this discipline,to have the students actively involved in this learning process.In this way,the students become the subjects of the class so that the quality of pathology teaching can be improved.

Objective To construct a recombinant eukaryotic vector expressing maspin cDNA,and to explore the effect of maspin overexprssion on the proliferation of human gastric carcinoma cell line SGC7901.Methods The fragment of maspin gene was amplified by polymerase chain reaction(PCR).An eukaryotic vector expressing maspin(maspin/PCR2.1)was constructed with PCR2.1,and transfected into SGC7901 cells.The expression of maspin at mRNA and protein level was detected by RT-PCR and Western blotting.The proliferation of SGC7901 cells was observed by MTT.Cell cycle was analyzed by flow cytometry.Results Recombinant plasmid maspin/PCR2.1 was constructed and transfected into SGC7901 successfully.The mRNA and protein levels of maspin were significantly higher in the maspin/PCR2.1 group(33.6?1.2,23.4?1.6)than that in the blank PCR2.1(15.0?1.5,12.3?1.5)and the untreated group(13.7?2.0,12.0?1.3)(P

Objective To investigate the inhibitory effect of maspin gene on metastasis and invasion of gastric cancer and its mechanism.Methods Maspin gene was ligated to the expression vector PCR2.1 with T4 DNA ligase after the PCR2.1 was digested by HindⅢ/XbaⅠ.The recombinant vector maspin/PCR2.1 was transfected into human gastric cancer cell lines MKN28 and SGC7901,then the mRNA and protein expression changes of maspin gene,uPA and uPAR were detected respectively by PT-PCR and Western blotting.Results After identified by digestion and sequencing,the reconstructed plasmid was confirmed to contain the correct and full nucleotide sequence of maspin gene.The expressions of maspin gene were up-regulated in MKN28 and SGC7901 cell lines,while the expressions of uPA and uPAR were down-regulated.Conclusion The expression vector maspin/PCR2.1 is constructed successfully and can be expressed in eukaryotic cells.Expressions of uPA and uPAR can be inhibited by maspin gene.

Objective To investigate the inhibition effect in vitro of mucin gene MUC2 antisense oligodeoxynucleotide (ASODN) on its gene expression and proteolytic enzyme on gastric cancer cell line. Methods Phosphorothioated MUC2 ASODN were synthesized and transfected to SGC7901 cells mediated by lipofectin. MUC2 mRNA and MUC2 protein expressed on SGC7901 cells was detected by RT-PCR and immunohistochemical method. The inhibitory effects of ASODN on proteolytic enzyme, such as cathepsin D, MMP-2 and MMP-9 protein were detected by immunohistochemical staining. The cell cycle and apoptosis were determined by flow cytometry (FCM). Results The inhibition effects peaked at 48th hour after transfection, and the inhibition rate reached 55% when the concentration of ASODN was 0.5 ?mol/L. The number of the cells treated with MUC2 ASODN was decreased as compared to the control cells. MUC2 ASODN transfection could inhibit the transition period of S phase to G2/M phase, and G2/M did not change much. The apoptosis rate was about 4.38%. As compared with blank control group, MUC2 ASODN could significantly inhibit MUC2 mRNA expression of SGC7901 cells. ASODN could downregulate the expression levels of MUC2 protein, MMP-2 and cathepsin D protein. Conclusion MUC2 ASODN transfection could specifically inhibit SGC7901 cells by downregulating the expression levels of proteolytic enzyme.

The Golgi complex is the central organelle of the secretory pathway and has many complicate functions. The endeavours to isolate and purify the Golgi apparatus from cultured cells will benefit further investigation of Golgi. A large number of gastric cancer cells SGC7901 were cultivated in vitro, then Golgi apparatus were isolated from the cells by differential centrifugation combined with sucrose density gradient ultra-centrifugation. Its purity was characterized biochemically by enzymatic assays, morphologically by electron microscopy (EM) and neutral red supravital staining. Finally the Golgi complex was successfully fractionated from gastric cancer cells SGC7901. The first successful isolation of Golgi apparatus from gastric cancer cells SGC7901 by using ultra-centrifugation will lead to research into the function of Golgi apparatus.
Cell Line, Tumor ; Golgi Apparatus ; ultrastructure ; Histological Techniques ; Humans ; Stomach Neoplasms ; pathology ; ultrastructure