[Abstract ] Objective Difficulties with the preparation of gastric cancer stem cells (CSCs) have been a main obstacle to the studies of gastric cancer .This article addresses the technology of the serum-free medium suspension cultivation of the MKN-45 gastric cancer cell line and screening of stem cells from the cell line based on the biomarkers of gastric CSCs . Methods MKN-45 cells were cultured in serum-free medium for 8 weeks and those in the logarithmic phase cultivated with hoechst 33342 followed by detection of the side cells by flow cytometry .When the side population cells reached 25%, all the cell microspheres were collected , hatched with CD133 and CD44, and subjected to fluorescence-activated cell sorting.The CDl33 +and CD44 +cells were selected as gastric CSCs . Results About 40%of the MKN-45 gastric CSCs were alive , prolif-erated, and formed floating cell balls .Side population cells constitu-ted 3.4% of the MKN-45 cells and 26.9% of the cell balls.The CDl33 +and CD44 +cells made up 11.2% of the MKN-45 cells and 90.3%of the cell balls. Conclusion Cell balls rich in CSCs can be successfully obtained by serum-free medium suspension culti-vation and CSCs can be screened out with hoechst 33342 and surface markers , which may serve as an experimental ground for the stud-ies of gastric CSCs .

Objective To analyze the drug resistance of Helicobacter pylori (Hp) strains isolated from teenagers (aged 13 to 19) in Xiaoshan area to metronidazole,clarithromycin,levofloxacin,amoxicillin and furazolidone. Methods A retrospective study was conducted on 1 452 teenagers who had endoscopic examination in the First People′s Hospital of Xiaoshan District from January 2012 to December 2017. Statis-tical analysis was performed to analyze the antibiotic resistance of Hp to various antibiotics. Results Teen-agers who were positive for Hp infection accounted for 16.46% (239). The resistance rates of Hp isolates to metronidazole and clarithromycin were 71.55% and 16.74% with an upward trend in the past two years. Among all Hp isolates, those resistant to levofloxacin, amoxicillin and furazolidone accounted for 5.02%, 0.0% and 0.84%,respectively. No significant change in the antibiotic resistance patterns of Hp was ob-served. There were 15.06% of Hp isolates resistant to both metronidazole and clarithromycin. No statistical-ly significant difference in antibiotic resistance patterns was found between Hp isolates from male and female teenagers in Xiaoshan area. Conclusion This study suggested that the Hp isolates showed high resistance to metronidazole,moderate resistance to clarithromycin and levofloxacin,and low resistance to amoxicillin and furazolidone. Attention should be paid to monitoring the antibiotic resistance patterns in teenagers and pro-moting individualized treatment with regard to the eradication strategy of Hp infection.

Objective:To analyze Helicobacter pylori ( Hp) resistance in Xiaoshan area from 2013 to 2020 and to provide reference for the selection of clinical antibiotics for the eradication of Hp in this area. Methods:Non-repetitive Hp strains isolated from patients treated in the First People′s Hospital of Xiaoshan District, Hangzhou from January 2013 to December 2020 and the drug susceptibility test results of these strains were collected. The patients were grouped by every 10 years of age to analyze the drug resistance of Hp in different groups and its changing trends. Results:A total of 54 912 Hp strains were isolated and cultured. The resistance rates of Hp isolates to amoxicillin, metronidazole, clarithromycin and levofloxacin were 0.42%, 92.94%, 22.41% and 29.83%, respectively. The drug resistance rates to clarithromycin and levofloxacin were increasing year by year. The resistance rates to levofloxacin, clarithromycin and metronidazole increased with age. The resistance rates to clarithromycin, levofloxacin and metronidazole in women were higher than those in men, especially in the 21-60 age group. The resistance rate to clarithromycin was significantly higher in people under 20 years old. In 2017 to 2019, the resistance rate to amoxicillin was higher in people under 20 years old than in other age groups. In 2020, the resistance rates to levofloxacin and clarithromycin in people over 70 years old both exceed 57% and increased rapidly. Conclusions:The resistance rates of Hp to levofloxacin, clarithromycin and metronidazole in Xiaoshan area were all at a high level. It was recommended to use individualized treatments for the eradication of Hp. In addition, attention should be paid to the young and older people.

Objective: To explore the method of extracting chaperone antigen peptide complexes from gastric cancer stem cells and its immune function. Methods: Gastric cancer stem cells and gastric cancer cells were screened by low temperature ultrasonic lysis. After salting out and dialysis, the lysate supernatant was processed with SDS-PAGE to analyze the expression of chaperone antigen peptide complexes, and then was separated and purified with CNBr-activated SepharoseTM 4B. Reverse high pressure liquid chromatography (HPLC), SDS-PAGE and Western blotting were used to analyze the purity and nature of the acquired albumen. Lymphocyte proliferation assay and lymphocytotoxicity assay were used to ditermine the immunological activity of the chaperone-antigen peptide complexes. Results: The chaperone antigen peptide complexes of gastric cancer stem cells were prepared and identified successfully, of which the main components were the antigen peptides of HSP60, HSP70, HSP90 and HSP110. 0.75 μg and 1.00 μg HSP70-antigen peptide and 1.00 μg HSP90-antigen peptide activated lymphocytes significantly. Their A₄₉₀ values were 0.26±0.03, 0.45±0.05 and 0.32±0.04, respectively, while the corresponding doses of HSP60-antigen peptide and HSP110-antigen peptide did not activate lymphocytes. The killing rates of 1.00 μg HSP70-antigen peptide and 1.00 μg HSP70 were (45.0±2.0)% and (16.0±2.0)%, respectively, showing a significant difference (P=0.012). Similarly, the killing rates of 1.00 μg HSP90-antigen peptide and 1.00 μg HSP90 were (36.0±5.0)% and (13.0±4.0)%, respectively, also showing a significant difference (P=0.048). Conclusions The amount of chaperone antigen peptide complexes in gastric cancer cells is extremely low, but it is obviously increased in gastric cancer stem cells. After purification, the chaperone antigen peptide complexes with high purity can be prepared. The extracted chaperone antigen peptide complexes have stronger immunogenicity, and can be used to make tumor vaccine in vitro, which may have a good application value in the targeted therapy of gastric cancer.

COVID-19/virology* ; China/epidemiology* ; Disease Outbreaks ; Genetic Linkage ; Humans ; Phylogeny ; Polymorphism, Single Nucleotide ; SARS-CoV-2/isolation & purification*