Objective To investigate the effects of estrogen on mismatch repiar gene expression in colonic mucosa in vivo. Methods A total of 42 healthy individuals underwent colonoscopy were enrolled in the study. Half an hour before colonoscopy examination, blood sample was taken for determining the serum estradiol (E2) level. N ormal colonic mucosal tissues determined by naked eye under colonoscopy examination were taken in the right hemi colon to detect HMLH1 and hMSH2 gene expression by semi-quantitative RT-PCR and immunohistochemistry staining. Then the correlation of serum E2 levels with hMLH1 and hMSH2 expression in colonic mucosa was analyzed. Results A bimodal curve was presented for the correlation between serum E2 level in healthy individuals and hMLH1 expression in colonic mucosa. A strong positive correlation of E2 level with hMLH1 expression in normal colonic mucosa was observed when serum E2 level was more than 45 pg/ml (For mRNA, P=0. 003, r=0. 701; for immunohistochemistry positivity index, P=0. 000, r=0. 874).However there was no correlation between E2 level and hMSH2 expression. Conclusion High serum E2 level might increase the hMLH1 gene expression in colonic mucosa in vivo.

Objective To identify clinicopathological features of high MSI (MSI-H).Methods We enrolled 150 patients,standard microsatellite loci (BA T25,BA T26,D2S123,D5S346,D17S250) were amplified by polymerase chain reaction(PCR) with fluorescent primers,and the PCR products were analyzed by GeneMapper software;age at diagnosis,gender and site were obtained;various pathological features were observed by light microscopy;the expression of tumor infiltrating lymphocytes (CD4~+ and CD8~+) was detected by immunohistochemistry.Using a stepwise logistic regression model,a formula was generated that could be used to calculate the probability of a colorectal carcinoma being MSI-H based on pathological features.Results Among 150 cancers,MSI-H was 13.33%.Independent identifiers inclucle poor differentiation,histologic heterogeneity,Crohn's-like reaction and tumor-infiltrating lymphocytes,logistic regression formula shows a sensitivity of 70.0% and a specificity of 99.2% and a accurate ratio of 95.3% for MSI-H.Conclusion MSI-H phenotype cancer is a type of nonfamilial colorectal cancer with specific pathological features,Clinicopathological features can efficiently identify MSI-H colorectal cancers.

Objective To compare the safety and clinical value of warm-water infusion or carbon dioxide(CO2)insufflation in difficult colonoscopy.Methods A collection of 150 patients from May 2021 to October 2023 who underwent unsedated and difficult colonoscopy were randomly divided into warm-water insufflation group(W group,n=50),CO2 insufflation group(C group,n=50)and air insufflation group(A group,n=50).Record the cecal insertion time,the abdominal pain score during the examination and 20 min and 1 h after the examination,the success rate of intubation,the polyps detection rate,the willingness to re-examine and the need for assistance in the three groups.Some patients were randomly selected to record partial pressure of end-tidal carbon dioxide(PetCO2)of pre-examination,the ileocecal and 20 min after the examination to understand CO2 retention in the body.Results The cecal insertion time of group A was longer than that of group W and group C,and group W was shorter than group C.The abdominal pain score of group A was higher than that of group W and group C at each time point,and the abdominal pain score during the examination was lower in the group W compared with group C.The success rate of intubation and the willingness to re-examination in the group A were lower than those in group W and group C,The above differences were statistically significant(P<0.05).However,there was no statistical difference between the the group W and group C in terms of success rate of intubation,willingness to re-examine,and abdominal pain score at 20 minutes and 1 hour after the examination(P>0.05).In the group W,significantly fewer patients required abdominal compression compared with the other two groups,and the rate of position conversion was significantly lower than that in group A(P<0.05).There was no significant difference in the detection rate of polyps among the three groups(P>0.05).In addition,PetCO2 of group C was within the normal range at all time points,and there was no statistical difference compared with the group A(P>0.05).Conclusion Compared with the air group,water or CO2 insufflation colonoscopy is safe and has a high success rate in difficult colonoscopy.It can reduce the patient's abdominal discomfort,especially water insufflation colonoscopy is more suitable for promotion in primary hospitals.