ABSTRACT
Objective:To investigate Helicobactor pylori (H. pylori) infection status and interfamilial transmission pattern in Zhengzhou area. Methods:A cross-sectional study was conducted from September 2020 to march 2021, among 731 individual from 266 families randomly selected from 9 communities of Zhengzhou area. H. pylori infection status was determined by serum antibody tests, and 13C-urea breath test was performed in the previously eradicated population to clarify the current infection status. The individual and familial infection rate, infection status for couples and children and adolescent were analyzed. Results:Among 731 individuals from 266 families, 397 of them were H. pylori positive. The individual infection rate was 54.31% (397/731); among infected individuals 77.83% (307/397) were infected with type Ⅰ strain, 22.67% (90/397) were infected by type Ⅱ strain. Annual household income ( χ2=0.419, 0.410, 0.213, all P>0.05), smoking history (χ 2=0.071, P>0.05), drinking history ( χ2=0.071, P>0.05), dining place ( χ2=0.009, P>0.05), gastrointestinal symptoms ( χ2=0.047, P>0.05), family history of gastric disease ( χ2=0.069, P>0.05), and history of gastric cancer ( χ2=0.004, P>0.05) had no significant differences between H. pylori-positive and -negative groups, but the infection rate in individuals with higher education level was lower ( χ2=4.449, P<0.05). The infection rate was significantly higher in≥18 age groups compared with<18 age groups ( χ2=6.531, 23.362, 20.671, 24.244, 37.948, 14.597 and 5.170, all P<0.05). The familial H. pylori infection rate was 87.59% (233/266), and in 61 families all member were infected (26.18%, 61/233). The positive rate was 23.08% (6/26) in 50 families with children under 18 years when both parents were infected. Among 231 coupled families, both couples were infected in 78 families (33.76%), one couple was infected in 113 families (48.92%), and both couples were not infected in 40 (17.32%). With the increase of marriage time, the infection rate of both spouses increased significantly ( χ2=7.775, 12.662, 15.487, all P<0.05). Conclusions:The distribution of H. pylori infection presents a family cluster pattern, and intrafamilial infection is an important transmission rout of H. pylori. The type I strain of H. pylori is the dominate strain in this area.
ABSTRACT
Objective To introduce a practical method that can be used to efficiently express,purify and identify Alzheimer's disease (AD) related beta-site app-cleaving enzyme 1 (BACE1) in common eukaryotic cells.Methods BACE1 cDNA was fished out from human brain cDNA library and ligated into the pEGFP-c3 expression vector,and then,the recombinant plasmid was transfected into the HEK293 cells.The BACE1 protein was purified with TALON Mental Affinity Resins column.The target protein was identified by Western blotting and fluorescence resonance energy transfer (FRET).BACE1 Activity Assay Kit was employed to test the activity of purified BACE1 in vitro.The recombinant BACE1/pEGFP-c3 plasmid and amyloid precusor protein (APP)/pDsRed-Monomer-N1 plasmid were co-transfected to the HEK293 cells and the cleavage activity of BACE1 in the cells was identified by Western blotting.Results The sequencing data of the obtained BACE1 gene were identical with those in GenBank.Activity test showed that the fluorescent values of blank controls,expressed BACE1 and standard BACE1 were 55.013±3.597,1836.629±154.195 (n=3) and 2639.548±207.1901 (n=3),respectively;as compared with the control group,significant differences were noted in both of the two groups (F=78.681,P=0.000);however,there is no significant difference between expressed BACE1 and standard BACE1 groups (P＞0.05).Westem blotting showed the co-transfected BACE1 could cleave APP in HEK293 cells and the CTF-APP band was detectable.Conclusion A practical protocol is established for high expression,purification and identification of BACE1 in HEK293 cells,which is helpful to obtain BACE1,an important molecular target in AD research and treatment.