Objective To detect the effect of cell density off both integrin αγβ6 expression and matrix metalloproteinase-9(MMP-9)secretion in colon cancer cells. Methods Flow cytometry was applied to analyze αγβ6 expression in human WiDr colon cancer cell lines and human HaCaT keratinocyte cells, respectively,at high-and low-cell density culture.The MMP-9 aetivity level for various coloIl cancer cell lines, WiDr and SW480 cells at high-and low-cell density culture was analyzed using Biotrak MMP-9 activity assay and Gelatin Zymography assay, respectively. Results High cell density significantly enhances integrin αγβ6 expression for WiDr cells expressing αγβ6 compared with low density,but no increase was observed for human keratinocyte HaCaT cells. Biotrak MMP-9 assay indicated that the amount of MMP-9 secreted per cell for WiDr and SW480 B6 cells at high cell density culture was(3.3±1.2)×10-7ng/cell and(27.2±3.0)× 10-7ng/cell respectively; However,at low cell density it was(1.8±0.7)× 10-7ng/cell and(10.9±2.0)×10-7 ng/cell,respectively. It was 2-3-fold higher for WiDr and SW480 β6 cells at high cell density compared with that at low cell density, but no density-dependent increase observed for SW480 wild cells lack αγβ6 expression(t=0.47,P＞0.05),MMP-9 secretion for SW480 wild cells was(3.9±1.7)× 10-7 ng/cell at hish cell density and(3.8 ±0.7)×10-7 ng/cell at low eell density(P＞0.05),respectively. Gelatin zymography assay also indicated that the level of MMP-9 in SW480 B6 cells expressing αγβ6 was evidently higher at high density than at low density, however no density-dependent increase observed for SW480 wild cells and HaCaT cells. Conclusions High cell density induces integrin αγβ6 expression and promotes MMP-9 secretion in colon cancer cells, which constitutes the basis for a self-perpetuating system of tumor infiltrating growth in colon cancer progression.

Objective To explore the relationship between the antiviral effect and peripheral blood mononuclear cell (PBMC) hepatitis B virus (HBV) DNA when the patients reach the standard of withdrawal of antiviral therapy in chronic hepatitis B (CHB).Methods Ninety CHB patients treated with interferon(n=44) or nucleot (s) ide(n=46) who reached the standard of withdrawal of antiviral therapy were recruited.HBV DNA levels in PBMCs were tested at the end of treatment,and its relationship with serum HBV DNA level before treatment in PBMC HBV DNA positive group and negative group were compared.The correlation between HBV DNA in PBMCs at the end of treatment and relapse were explored.Measurement data were analyzed by student t test and enumeration data were analyzed by X2 test.Results Among 90 patients,67(74.4%) were PBMC HBV DNA negative at the end of treatment,and 23(25.6%) were positive.The serum HBV DNA positive conversion rate in PBMC HBV DNA negative patients was 13.4%,which were significantly lower than that in positive group (73.9%) (X2=30. 4873, P<0.01 ). There were no significant differences of alanine aminotransferase (ALT) levels when hepatitis flare (t=0. 8729, P=0. 3913) and relapse time (t=1. 9222, P=0. 0665) between PBMC HBV DNA negative group and positive group after withdrawal of therapy, while the serum HBV DNA rebound was greater in positive group than that in negative group (t=2. 7493, P=0. 0112). There were five patients who achieved hepatitis B surface antigen (HBsAg) seroconversion, whose PBMC HBV DNA were all undetectable, and none relapsed during follow-up for 6-12 months. The pretreatment HBV DNA as level in PBMC HBV DNA positive was (7.2±1.1) lg copy/mL, which was much higher than that in negative group[(5.2±2.1) lg copy/mL] (t=4. 3557, P<0.01). Conclusions In patients who reach the standard of drug withdrawal,PBMC HBV DNA at the end of treatment is an important predictor for durability of antiviral therapy in CHB.

OBJECTIVETo evaluate the status of eight RHD specific exons in 131 Han Chinese blood donors who were classified as RhD-negative by serological methods and explore the genomic structure of RHD gene among the Han Chinese. The Rh blood group system has the highest prevalence of polymorphisms among human blood group systems and is clinically significant in transfusion medicine. The Rh antigens are expressed on polypeptides encoded by two highly homologous genes, RHD and RHCE. Recent molecular studies have shown that the RhD-negative trait could be generated by multiple genetic mechanisms and is ethnic group-dependent.

METHODSThe polymerase chain reaction using-sequence specific primers (PCR-SSP) was used to amplify exons 2, 3, 4, 5, 6, 7, 9 and 10 of RHD gene and exons 1, 2 and 5 of RHCE gene, as well as intron 4 in each of them.

RESULTSThe 131 cases of RhD-negative phenotypes consisted of 60 ccee, 58 Ccee, 5 ccEe, 5 CcEe and 3 CCee. Among them, 83 with the Rh ccee or ccEe phenotypes (63.4%) lacked the eight RHD exons indicated above, while 26 cases with the Rh Ccee, CCee, CcEe phenotypes (19.9%) had all the RHD exons examined. Twenty-two individuals with the Ccee, CCee, CcEe phenotypes (16.8%) carried at least one RHD exon. The phenotypes of the RhD negative individuals carrying the RHD gene were Rh CC or Cc, but not cc.

CONCLUSIONSThree classes of RhD-negative polymorphisms among a population of Han Chinese were observed. Antigen association analysis suggested the existence of a novel class of RhD-negative associated haplotype in Han Chinese. This haplotype consisted of a normal RHCE allele and a nonfunctional RHD gene. It may be beneficial to redefine the RhD-negative blood group among Chinese populations upon clarification of the mechanisms of RHD gene expression and RhD antigen immunization.

Asian Continental Ancestry Group ; China ; Ethnic Groups ; genetics ; Humans ; Phenotype ; Polymerase Chain Reaction ; Polymorphism, Genetic ; Rh-Hr Blood-Group System ; analysis ; genetics