A questionnaire was used to survey the perspective of the 22 mentors,24 students, 27 graduate students and 27 public health units on the competence of MPH student. The result showed that the practice skill,analyzing skill,program plan and practice skill,and emergency reaction abil-ity got more attention. This suggested that to the training of MPH,the training objective should focus on the ability to resolve problems; the curriculum should focus on the characters of public health and on the practice training.

Serrated polyposis syndrome (SPS) is closely associated with the initiation and development of colorectal cancer (CRC), however, there is few research on SPS in China. Serrated polyps can be divided into hyperplastic polyps, sessile serrated polyps and traditional serrated polyps. The diagnosis standard of SPS is as following: (1) There are at least 5 serrated lesions in proximal colon, and diameter of more than 2 lesions is >10 mm; (2) The patient has one serrated polyp with family history of SPS; (3) More than 20 serrated polyps can be found in the entire large bowel. The risk of SPS is relatively high in the development of colorectal cancer and 25%-70% of the SPS patients is diagnosed with synchronous or metachronous colorectal cancer during following-up. The clinical characteristics of SPS include that patients are relatively old; no significant racial difference exists in the morbidity; patients have family history of colorectal cancer. The mutation of BRAF or KRAS gene, which induces colorectal cancer through the RAS-RAF-MAPK signaling pathway, is often found in SPS as well as CpG island methylation phenotype (CIMP) and microsatellite instability (MSI). The difference between SPS and traditional familial adenomatous polyposis (FAP) should be noted because of the different pathology mechanism, clinical characteristics and the risk of malignancy. Nowadays, the common technologies of detecting serrated polyps are auto-fluorescence imaging (AFI) and narrow-band imaging (NBI), whose detective rate is around 55%. The SPS patients are advised to undergo the resection of all the serrated polyps with diameter larger than 3-5 mm and receive the colonoscopy examination every 1 or 2 year. Not only the research about SPS is on the initiation step and the molecular mechanism is still unknown, but also the scholars do not come to achieve agreement about the risk of SPS in the malignancy of colorectal cancer, which is essential for further research therefore.
Adenoma ; genetics ; pathology ; therapy ; Adenomatous Polyposis Coli ; genetics ; pathology ; therapy ; Colonic Polyps ; Colonoscopy ; Colorectal Neoplasms ; genetics ; pathology ; therapy ; DNA Methylation ; Genes, ras ; Humans ; Microsatellite Instability ; Mutation ; Phenotype ; Proto-Oncogene Proteins B-raf ; Syndrome

Objective The aim of this study was to establish an acute gastric mucosal injury(AGMI)rat model induced by hydrochloric acid(HCl)at different concentration gradients and to investigate the effects of intravenous injection of evans blue(EB)at various concentrations and dosages on survival rate and superficial extravasation.Methods(1)Wistar rats were randomly assigned to five weight-based groups:150～180 g,180～200 g,200～250 g,300～400 g,400～500 g.Each group was further subdivided into eight subgroups based on HCl concentration,specifically:0.40,0.45,0.50,0.55,0.60,0.65,0.70 mol/L HCl,along with a control group treated with saline.This result ed in a total of 40 subgroups,with three rats per subgroup,summing up to 120 animals in total.The survival rate of rats 24 hours post-modeling was assessed,and the interaction between body weight and HCl concentration on rat survival was analyzed.Following the establishment of five graded HCl concentrations,gastric mucosal pathological changes were observed microscopically using hematoxylin-eosin staining(HE)staining.(2)From these result,the highest suitable concentration of HCl was selected to prepare the AGMI model.Subsequently,rats were randomly allocated into different groups based on the concentration and dose of EB,specifically:EB 1(0.5％,0.4 mL),EB 2(1％,0.1 mL/100 g),EB 3(1％,0.2 mL/100 g),EB 4(2％,0.1 mL/100 g),EB 5(2％,0.2 mL/100 g),and EB 6(5％,0.1 mL).Each group consisted of five rats,totaling 30 animals.The survival rate and extent of dermal exudation were evaluated 24 hours post-injection of EB.Results(1)Post-modeling symptoms in AGMI rats intensified with increasing concentrations of HCl,with the 24-hour survival rate in all weight groups being 0％for both 0.65 mol/L and 0.70 mol/L HCl.Kaplan-Meier survival curves indicated significant differences in survival rates among rats in different HCl concentration groups(P＜0.001).Furthermore,a significant interaction effect between HCl concentration and body weight on rat survival time was observed(P＜0.001).The five gradient HCl concentrations established were from 0.40、0.45、0.50、0.55、0.60 mol/L.Histological observations revealed that the degree of inflammatory cell infiltration in the gastric mucosa of AGMI rats escalated with increasing HCl concentrations.(2)AGMI rats prepared with 0.60 mol/L HCl and injected with 5％EB(0.1 mL)had a 24 h survival rate of only 40％.Kaplan-Meier survival curves showed no significant differences in survival rates among AGMI rats under different concentrations and dosages of EB(P＞0.05).Analysis of superficial extravasation revealed that skin and eye color were lighter in EB 1 group rats,with fewer extravasation points,while rats in EB 4 and EB 5 groups exhibited more apparent skin color changes and extravasation.One-way ANOVA further confirmed that the number of superficial EB extravasation points in the EB 3,EB 4,and EB 5 groups was significantly higher than that in EB 1 group(P＜0.05,P＜0.01).Conclusions HCl modeling successfully achieved a setting of multiple precise concentration gradients.Gastric lavage with HCl concentrations ranging from 0.40 mol/L to 0.60 mol/L in rats with a fasting body weight of 180～200 g was used to successfully prepare an AGMI model.Intravenous injection of 2％EB(0.2 mL/100 g)can facilitate the study and analysis of the distribution characteristics of superficial EB extravasation points in AGMI rats over time and as the condition progresses.

Objective The study aimed to explore the main forms of double minute chromosomes(DMs)in the cell cycle of colorectal cancer at different phases,and to clarify the replication and separation phases of DMs.Methods After using serum-free starvation to block the progression of cell cycle in colorectal cancer COLO 320DM cells,Calyculin-A was used to induce interphase cells to prepare karyotype samples through advanced chromatin condensation.COLO 320DM cells were treated with colchicine to ob-tain mitosis(M)phase cells for karyotype analysis.The karyotypes of cells at the early stage of DNA synthesis(G1 phase),the late stage of DNA synthesis(G2 phase),metaphase(M-mid),anaphase(M-late),and telophase(M-ter)of mitosis were observed and photographed under a regular optical microscope,and counted the number of DMs.Results DMs mainly existed in monotypic form at the G1 phase,M-late phase and M-ter phase of cells.In the G2 and M-mid phases of cells,DMs mainly existed in a diploid form.Conclusion Monomeric DMs undergo replication in the S phase and transform from monomers to diploids,while diploid DMs in the M-late phase complete separation and transition from diploids to monomers.