In environmental epidemiological research, extensive non-random environmental exposures and complex confounding biases pose significant challenges when attempting causal inference. In recent years, the introduction of causal inference methods into observational studies has provided a broader range of statistical tools for causal inference research in environmental epidemiology. The instrumental variable (IV) approach, as a causal inference technique for effectively controlling unmeasured confounding factors, has gradually found application in the field of environmental epidemiological research. This article reviewed the basic principles of IV and summarized the current research progress and limitations of applying IV for causal inference in environmental epidemiology. IV application in the field of environmental epidemiology is still in the initial stage. Rational use of IV and effective integration with other causal inference methods will become the focus of the development of causal inference in environmental epidemiology. The aim of this paper is to provide a methodological reference and basis for future studies involving causal inference to target population health effects of environmental exposures in China.

OBJECTIVE To investigate the effects of soybean isoflavones （SI） on the reproductive development of young mice. METHODS C57BL/6 young mice were randomly divided into control group， SI low-dose and high-dose groups （10， 100 mg/kg）， with 10 mice in each group （half male and half female）. The young mice in each group were given corresponding liquid intragastrically， once a day， for 2 consecutive weeks. After the last administration， the percentage of body weight increase was calculated； serum estradiol and testosterone levels， malondialdehyde （MDA） content， total antioxidant capacity （T-AOC）， superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） activities in the reproductive organs of the young mice were determined. The histopathological changes in the reproductive organs were observed. The cell apoptosis of reproductive organs was detected. RESULTS Compared with the control group， the percentage of body weight increase in female mice was increased significantly in the SI high-dose group， while that of male mice was decreased significantly （P＜0.05 or P＜0.01）. Cystic follicles could be seen in the ovarian tissue in SI groups， a loose arrangement of spermatocytes could be seen in the testicular tissue， and partial epithelial cell shedding could be seen in epididymal tissue. The serum level of testosterone in female young mice and the serum levels of testosterone and estradiol in male young mice in SI groups， GSH-Px activity in the ovarian tissue of female young mice in the SI low-dose group， T-AOC activities in the ovarian tissue of female young mice in SI groups as well as the apoptotic rates of cells in testicular and epididymal tissue of male young mice in SI groups were increased significantly （P＜0.05 or P＜ 0.01）； the serum level of estradiol in female young mice in SI groups， SOD activity in the ovarian tissue of female young mice in the SI high-dose group， and MDA contents in the ovarian tissue of female young mice in SI groups as well as the apoptotic rates of cells in ovarian tissue of female mice in SI groups were decreased significantly （P＜0.05 or P＜0.01）. CONCLUSIONS SI can enhance the antioxidant stress capacity of ovarian tissue in female young mice and reduce their oxidative stress damage， but it has certain toxicity to reproductive organs in male mice.

Objective To investigate the application value of quantitative parameters MRFDGmax and SUVmax in the stages of hepatitis,liver fibrosis and cirrhosis in rats by whole-body dynamic 18 F-FDG PET/CT Patlak imaging.Methods Twenty-four SD rats were randomly divided into four groups of six rats each,which were the normal group,hepatitis group,liver fibrosis group and cirrhosis group.According to the experimental grouping,rats in each group were induced by the CC14 oil solution complex method.Whole-body dynamic 18 F-FDG PET/CT patlak imaging was performed on each group of rats separately at the completion of induction.After the imaging was com-pleted,the MRFDGmax,SUVmax and CT values of the livers of each group were analyzed;subsequently,the serum of rats in each group was extracted for the detection of liver function indexes(AST,ALT and ALP),and HE staining was performed on the livers of rats in the normal,hepatitis and cirrhosis groups,and Masson staining was performed on those in the liver fibrosis group;the α-SMA expression in the liver tissues of each group was analyzed by immu-nohistochemical method.The data were analyzed by one-way ANOVA,two independent samples t-test and Pearson correlation analysis.Results MRFDGmax,SUVmax values were statistically significant differences among normal,hep-atitis,liver fibrosis and cirrhosis groups(F=84.54,38.35,P＜0.001).The difference in CT values between liver fibrosis and cirrhosis groups was not statistically significant(t=-0.407,P=0.693),and the difference was statistically significant when compared between the rest of the groups(F=112.25,P＜0.001).Compared with the normal group,AST,ALT and ALP of the experimental group showed a staged increase,and the differences were statistically significant(F=93.32,64.63,145.03,P＜0.001).HE staining showed that hepatocytes of the normal group were neatly arranged and structurally intact;a large number of inflammatory cells infiltrated the hepa-titis group with steatosis;pseudo lobe formation was observed in the cirrhosis group.Masson staining of the liver fi-brosis group showed collagen fiber proliferation and thickening of the peritoneum.Immunohistochemistry test results showed that α-SMA expression increased in hepatitis group,liver fibrosis group and cirrhosis group,with a staged increase,and the difference was statistically significant(F=80.57,P＜0.001).Correlation analysis showed a positive correlation between SUVmax and MRFDGmax(r=0.967,P＜0.01).α-SMA was positively correlated with AST,ALT and ALP in the hepatitis,liver fibrosis and cirrhosis groups,respectively(r=0.924,0.756,0.934,P＜0.01).Conclusion Whole-body dynamic 18F-FDG PET/CT Patlak imaging has application value in monitoring hepatitis,liver fibrosis and cirrhosis stages through quantitative parameters MRFDGmax and SUVmax changes.

Objective To evaluate the effects of high-fat diet on the pharmacokinetics of metronidazole in Chinese healthy adult subjects.Methods This program is designed according to a single-center,randomized,open,single-dose trial.Forty-seven healthy subjects were assigned to receive single dose of metronidazole tablets 200 mg in either fasting and high-fat diet state,and blood samples were taken at different time points,respectively.The concentrations of metronidazole in plasma were determined by high performance liquid chromatography-mass spectromentry.Results The main pharmacokinetic parameters of metronidazole in fasting state and high-fat diet state were as follows:Cmax were(4 799.13±1 195.32)and(4 044.17±773.98)ng·mL-1;tmax were 1.00 and 2.25 h;t1/2 were(9.11±1.73)and(9.37±1.79)h;AUC0_t were(5.59±1.19)x 104 and(5.51±1.18)x 104 ng·mL-1·h;AUC0_∞ were(5.79±1.33)x 104 and(5.74±1.32)× 104 ng·mL-1·h.Compared to the fasting state,the tmaxof the drug taken after a high fat diet was delayed by 1.25 h(P＜0.01),Cmax,AUC0_t,AUC0-∞ were less or decreased in different degrees,but the effects were small(all P＞0.05).Conclusion High-fat diet has little effects on the pharmacokinetic parameters of metronidazole,which does not significantly change the degree of drug absorption,but can significantly delay the time to peak.

To research on area ossification ratio (AOR), a novel parameter for quantitatively assessing adolescent bone age by conventional ultrasonography, and evaluate the correlation between AOR and radiographic bone age.

To evaluate the correlation between ultrasound ossification ratio(OR) and exercise intensity among adolescents.

Objective To monitor and evaluate the synergistic antitumor effects of programmed death-1(PD-1)checkpoint inhibitor combined with radiation therapy through whole-body dynamic 18 F-Fluorodeoxy glucose positron emission computed tomography(18F-FDG PET/CT)and Patlak multi-parametric analysis.Methods B16F10 mel-anoma dual-tumor mouse model was established and randomly divided into control,PD-1 monoclonal antibody,ra-diation-only,and combination groups(n=6).Whole-body 18F-FDG PET/CT imaging was performed before and 24 hours post-treatment.The changes of maximum standardized uptake value(SUVmax)and metabolic rate of FDG(MRFDG)changes were analyzed and compared.Mice were then euthanized,tumors excised and underwent histo-pathology with HE,CD8,Ki-67 staining to assess immune infiltration and proliferation.Distal tumor volumes were monitored during treatment.Results At 24 hours post-treatment,in the primary tumors,SUVmax and MRFDG values increased compared to pre-treatment in the control group(P＜0.000 1),while they decreased in the combination treatment group(P＜0.000 1),with statistically significant differences.In the distal tumors,SUVmax and MRFDG values increased compared to pre-treatment in the control group,PD-1 monoclonal antibody group,and radiothera-py-alone group.The SUVmax differences were statistically significant in the control group before and after treatment(P＜0.000 1).MRFDG values in the distal tumors showed statistically significant differences in all three groups(P＜0.01 or P＜0.000 1).In the combination treatment group,SUVmax and MRFDG values in the distal tumors de-creased significantly compared to pre-treatment(P＜0.000 1).Post-treatment comparison of SUVmax and MRFDG values in the distal tumors showed that statistically significant differences in SUVmax and MRFDG values were observed among all groups except between the radiotherapy-alone and PD-1 monoclonal antibody groups(all P＜0.05).Im-munohistochemistry results showed that the mean absorbance value of CD8 T lymphocytes in the distal tumor was significantly higher than that in the other three groups(P＜0.001);the mean absorbance value of Ki-67 immuno-histochemistry in the distal tumor proliferation index was significantly lower than that in the other three groups(P＜0.001).Conclusion The synergistic effects of combined treatment reduced distal tumor growth.Whole-body 18F-FDG PET/CT Patlak multi-parametric imaging can monitor the synergistic effects of PD-1 antibody and radiotherapy in B16F10 melanoma,providing reliable imaging parameters for optimizing combinatorial therapies.

177Lu-prostate specific membrane antigen(PSMA)radio-ligand therapy has been approved abroad for advanced prostate cancer and has been in several clinical trials in China.Based on domestic clinical practice and experimental data and referred to international experience and viewpoints,the expert group forms a consensus on the clinical application of 177Lu-PSMA radio-ligand therapy in prostate cancer to guide clinical practice.

ICU-acquired weakness (ICU-AW) is a common complication in the intensive care unit (ICU). The occurrence of ICU-AW directly leads to prolonged ICU stays for critically ill patients, and in severe cases, it continues to affect their quality of life even after discharge. This article provides a comprehensive review of the research progress on ICU-AW based on domestic and foreign studies, aiming to provide a scientific overview of ICU-AW, including its definition, pathophysiology, diagnosis, screening tools, influencing factors, and potential intervention strategies, so as to promote timely planning and implementation of relevant screening and intervention measures.

Sishen Pills is a classic prescription for the treatment of spleen and kidney diarrhea,which has the effect of warming the kidney and the spleen,astringent intestine and antidiarrheal.In modern clinical application,the modified prescriptions based on Sishen Pills,combined with other treatments of TCM and integrated traditional Chinese and Western medicine are often used to treat ulcerative colitis with spleen-kidney yang deficiency syndrome,and the curative effect is remarkable.Experimental pharmacological studies have shown that Sishen Pills may achieve the purpose of ulcerative colitis by regulating the expression of related signaling pathway proteins,regulating inflammatory factors,inhibiting inflammatory response,regulating autophagy,regulating intestinal flora,improving intestinal mucosal permeability,repairing intestinal mucosal barrier,regulating cellular energy metabolism,anti-oxidative stress,regulating cellular immune function,etc.In this article,the research status of Sishen Pills in the treatment of ulcerative colitis was sorted out and summarized,in order to provide reference for further study of its mechanism and clinical application.