ObjectiveTo investigate the liver-protecting and anti-liver fibrosis effects of astragaloside Ⅳ （AS-Ⅳ） in vitro and in vivo， as well as its mechanism of action in intervention against liver fibrosis. MethodsIn the animal experiment， C57BL/6J mice were divided into control group， model group， low-dose AS-Ⅳ （20 mg/kg） group， and high-dose AS-Ⅳ （80 mg/kg） group. The mice were given intraperitoneal injection of carbon tetrachloride for 6 weeks to induce liver fibrosis， and since week 3 of injection， the mice in the low-dose AS-Ⅳ group and the high-dose AS-Ⅳ group were given AS-Ⅳ by gavage at a dose of 20 mg/kg and 80 mg/kg， respectively. The serum levels of alanine aminotransferase （ALT） and aspartate aminotransferase （AST） were measured after 4 weeks of administration， as well as the serum levels of hyaluronic acid （HA）， laminin （LN）， procollagen Ⅲ N-terminal peptide （PⅢNP）， and collagen type Ⅳ （Col-Ⅳ）. HE staining， picrosirius red staining， and Masson staining were used to observe liver histopathology and collagen deposition； RT-qPCR was used to measure the mRNA expression levels of Acta2， Col1a1， and Col3a1 in liver tissue， and Western blot was used to measure the protein expression levels of α-smooth muscle actin （α-SMA）， collagen type Ⅲ （Col-Ⅲ）， phosphatidylinositol 3-kinase （PI3K）， phosphorylated PI3K （pPI3K）， protein kinase B （Akt）， and phosphorylated AKT （p-Akt） in liver tissue； transcriptome sequencing was performed for liver tissue to identify differentially expressed genes and perform a bioinformatics analysis. In the cell experiment， transforming growth factor-β （TGF-β） was used to induce the activation of LX-2 cells， and the PI3K inhibitor LY294002 and the PI3K activator 740 Y-P were used for intervention. The cells were divided into control group， model group， AS-Ⅳ group， LY294002 group， and AS-Ⅳ+740 Y-P group， and the cells were harvested after 36 hours of intervention. Changes in the protein expression levels of α-SMA， Col-Ⅲ， pPI3K/PI3K， and pAkt/Akt in LX-2 cells were measured， as well as changes in the relative mRNA expression levels of Acta2， Col1a1， and Col3a1. A one-way analysis of variance was used for comparison of continuous data between multiple groups， and the least significant difference t-test was used for further comparison between two groups. ResultsIn the animal experiment， compared with the model group， the AS-Ⅳ treatment group had significant reductions in the serum levels of ALT， AST， HA， LN， PⅢNP， and Col-Ⅳ （all P<0.01）， the mRNA expression levels of Acta2， Col1a1， and Col3a1 in liver tissue （all P<0.05）， and the protein expression levels of α-SMA， Col-Ⅲ， pPI3K， and pAkt （Ser473） in liver tissue （all P<0.05）. In the cell experiment， compared with the control group， the model group had significant increases in the protein expression levels of α-SMA， Col-Ⅲ， pPI3K， and pAkt （Ser473） after TGF-β induction （all P<0.05）； compared with the model group， the AS-Ⅳ group had significant reductions in the protein expression levels of α-SMA， Col-Ⅲ， pPI3K， and pAkt （Ser473） （all P<0.05）， and both the AS-Ⅳ group and the LY294002 group had significant reductions in the protein expression level of pPI3K and the relative mRNA expression levels of Acta2， Col1a1， and Col3a1 （all P<0.05）. Compared with the AS-Ⅳ group， there were significant increases in the protein expression level of pPI3K and the relative mRNA expression levels of Acta2， col1a1， and Col3a1 after 740 Y-P intervention （all P<0.05）. ConclusionAS-Ⅳ can inhibit hepatic stellate cell activation and improve liver fibrosis， possibly by inhibiting the PI3K/Akt signaling pathway.

Objective:To examine the impact of varied surgical treatment strategies on the prognosis of patients with initial resectable gastric cancer liver metastases (IR-GCLM).Methods:This is a retrospective cohort study. Employing a retrospective cohort design, the study selected clinicopathological data from the national multi-center retrospective cohort study database, focusing on 282 patients with IR-GCLM who underwent surgical intervention between January 2010 and December 2019. There were 231 males and 51 males, aging ( M(IQR)) 61 (14) years (range: 27 to 80 years). These patients were stratified into radical and palliative treatment groups based on treatment decisions. Survival curves were generated using the Kaplan-Meier method and distinctions in survival rates were assessed using the Log-rank test. The Cox risk regression model evaluated HR for various factors, controlling for confounders through multivariate analysis to comprehensively evaluate the influence of surgery on the prognosis of IR-GCLM patients. A restricted cubic spline Cox proportional hazard model assessed and delineated intricate associations between measured variables and prognosis. At the same time, the X-tile served as an auxiliary tool to identify critical thresholds in the survival analysis for IR-GCLM patients. Subgroup analysis was then conducted to identify potential beneficiary populations in different surgical treatments. Results:(1) The radical group comprised 118 patients, all undergoing R0 resection or local physical therapy of primary and metastatic lesions. The palliative group comprised 164 patients, with 52 cases undergoing palliative resections for gastric primary tumors and liver metastases, 56 cases undergoing radical resections for gastric primary tumors only, 45 cases undergoing palliative resections for gastric primary tumors, and 11 cases receiving palliative treatments for liver metastases. A statistically significant distinction was observed between the groups regarding the site and the number of liver metastases (both P<0.05). (2) The median overall survival (OS) of the 282 patients was 22.7 months (95% CI: 17.8 to 27.6 months), with 1-year and 3-year OS rates were 65.4% and 35.6%, respectively. The 1-year OS rates for patients in the radical surgical group and palliative surgical group were 68.3% and 63.1%, while the corresponding 3-year OS rates were 42.2% and 29.9%, respectively. A comparison of OS between the two groups showed no statistically significant difference ( P=0.254). Further analysis indicated that patients undergoing palliative gastric cancer resection alone had a significantly worse prognosis compared to other surgical options ( HR=1.98, 95% CI: 1.21 to 3.24, P=0.006). (3) The size of the primary gastric tumor significantly influenced the patients′ prognosis ( HR=2.01, 95% CI: 1.45 to 2.79, P<0.01), with HR showing a progressively increasing trend as tumor size increased. (4) Subgroup analysis indicates that radical treatment may be more effective compared to palliative treatment in the following specific cases: well/moderately differentiated tumors ( HR=2.84, 95% CI 1.49 to 5.41, P=0.001), and patients with liver metastases located in the left lobe of the liver ( HR=2.06, 95% CI 1.19 to 3.57, P=0.010). Conclusions:In patients with IR-GCLM, radical surgery did not produce a significant improvement in the overall prognosis compared to palliative surgery. However, within specific patient subgroups (well/moderately differentiated tumors, and patients with liver metastases located in the left lobe of the liver), radical treatment can significantly improve prognosis compared to palliative approaches.

ObjectiveTo investigate the therapeutic effect of ganoderic acid A （GA-A） on a mouse model of concanavalin A （ConA）-induced autoimmune hepatitis （AIH）. MethodsA total of 35 mice were randomly divided into control group （NC group）， model group （ConA group）， and low-， middle-， and high-dose GA-A treatment groups （GA-A-L， GA-A-M， and GA-A-H groups， respectively）， with 7 mice in each group. ConA was injected via the caudal vein of mice to establish a classic mouse model of AIH， and different doses of GA-A were administered via intraperitoneal injection 1 hour later for treatment. Proteomic techniques were used to investigate the protective mechanism of GA-A on hepatocytes， and HL-60 cells were differentiated into dHL-60 neutrophils by all-trans retinoic acid in vitro to validate the mechanism of action of GA-A. Related indicators were measured， including inflammatory markers （the activities of serum alanine aminotransferase ［ALT］ and aspartate aminotransferase ［AST］， HE staining， and inflammation-related genes）， apoptosis markers （TUNEL staining）， neutrophils， and neutrophil extracellular trap （NET） markers （myeloperoxidase ［MPO］， citrullinated histone H3 ［CitH3］， Ly6G， and free double-stranded DNA ［dsDNA］）， and p38 phosphorylation markers. The independent samples t-test was used for comparison of continuous data between two groups； a one-way analysis of variance was used for comparison between multiple groups， and the least significant difference t-test was used for further comparison between two groups. ResultsCompared with the NC group， the ConA group had significant increases in the serum levels of ALT and AST （both P<0.001）， and compared with the ConA group， GA-A treatment significantly reduced the levels of ALT and AST （both P<0.01）. HE staining showed that the mice in the ConA group had significant liver necrosis， while GA-A treatment significantly reduced the area of liver necrosis and the number of TUNEL-positive cells （both P<0.05）. Compared with the ConA group， the GA-A group had significant reductions in the expression levels of the inflammatory factors interleukin-6， tumor necrosis factor-α， and interferon gamma in serum and liver tissue （all P<0.05）. The proteomic analysis showed that GA-A alleviated ConA-induced acute immune liver injury by inhibiting the release of NET and the p38 MAPK pathway. Immunofluorescent staining of mouse liver tissue showed that compared with the ConA group， the GA-A group had significant reductions in the number of MPO-positive neutrophils and the number of cells with positive Ly6G and CitH3 （all P<0.01）. Western Blot and dsDNA testing showed that GA-A significantly inhibited the levels of the NET markers dsDNA and CitH3 and the level of p38 phosphorylation in liver tissue and dHL-60 cells （all P<0.05）. ConclusionGA-A alleviates liver inflammatory response and hepatocyte death by inhibiting the p38 MAPK pathway and the release of NET， thereby alleviating ConA-induced acute immune liver injury. This study provides a theoretical basis for the use of GA-A to treat immune liver injury by regulating neutrophil function.

Objective:To investigate the prognosis of patients with initially resectable gastric cancer liver metastasis (GCLM) who were treated by different modalities, and analyze the influencing factors for prognosis of patients.Methods:The retrospective cohort study was conducted. The clinicopathological data of 327 patients with initially resectable GCLM who were included in the database of a nationwide multicenter retrospective cohort study on GCLM based on real-world data from January 2010 to December 2019 were collected. There were 267 males and 60 females, aged 61(54,68)years. According to the specific situations of patients, treatment modalities included radical surgery combined with systemic treatment, palliative surgery combined with systemic treatment, and systemic treatment alone. Observation indicators: (1) clinical characteristics of patients who were treated by different modalities; (2) prognostic outcomes of patients who were treated by different modalities; (3) analysis of influencing factors for prognosis of patients with initially resectable GCLM; (4) screening of potential beneficiaries in patients who were treated by radical surgery plus systemic treatment and patients who were treated by palliative surgery plus systemic treatment. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the independent sample t test. Measurement data with skewed distribution were represented as M( Q1, Q3), and comparison between groups was conducted using the rank sum test. Count data were described as absolute numbers or percentages, and comparison between groups was conducted using the chi-square test. The Kaplan-Meier method was used to calculate survival rate and draw survival curve, and Log-Rank test was used for survival analysis. Univariate and multivariate analyses were conducted using the COX proportional hazard regression model. The propensity score matching was employed by the 1:1 nearest neighbor matching method with a caliper value of 0.1. The forest plots were utilized to evaluate potential benefits of diverse surgical combined with systemic treatments within the population. Results:(1) Clinical characteristics of patients who were treated by different modalities. Of 327 patients, there were 118 cases undergoing radical surgery plus systemic treatment, 164 cases undergoing palliative surgery plus systemic treatment, and 45 cases undergoing systemic treatment alone. There were significant differences in smoking, drinking, site of primary gastric tumor, diameter of primary gastric tumor, site of liver metastasis, and metastatic interval among the three groups of patients ( P<0.05). (2) Prognostic outcomes of patients who were treated by different modalities. The median overall survival time of the 327 pati-ents was 19.9 months (95% confidence interval as 14.9-24.9 months), with 1-, 3-year overall survival rate of 61.3%, 32.7%, respectively. The 1-year overall survival rates of patients undergoing radical surgery plus systemic treatment, palliative surgery plus systemic treatment and systemic treatment alone were 68.3%, 63.1%, 30.6%, and the 3-year overall survival rates were 41.1%, 29.9%, 11.9%, showing a significant difference in overall survival rate among the three groups of patients ( χ2=19.46, P<0.05). Results of further analysis showed that there was a significant difference in overall survival rate between patients undergoing radical surgery plus systemic treatment and patients undergoing systemic treatment alone ( hazard ratio=0.40, 95% confidence interval as 0.26-0.61, P<0.05), between patients undergoing palliative surgery plus systemic treatment and patients under-going systemic treatment alone ( hazard ratio=0.47, 95% confidence interval as 0.32-0.71, P<0.05). (3) Analysis of influencing factors for prognosis of patients with initially resectable GCLM. Results of multivariate analysis showed that the larger primary gastric tumor, poorly differentiated tumor, larger liver metastasis, multiple hepatic metastases were independent risk factors for prognosis of patients with initially resectable GCLM ( hazard ratio=1.20, 1.70, 1.20, 2.06, 95% confidence interval as 1.14-1.27, 1.25-2.31, 1.04-1.42, 1.45-2.92, P<0.05) and immunotherapy or targeted therapy, the treatment modality of radical or palliative surgery plus systemic therapy were independent protective factors for prognosis of patients with initially resectable GCLM ( hazard ratio=0.60, 0.39, 0.46, 95% confidence interval as 0.42-0.87, 0.25-0.60, 0.30-0.70, P<0.05). (4) Screening of potentinal beneficiaries in patients who were treated by radical surgery plus systemic treatment and patients who were treated by palliative surgery plus systemic treatment. Results of forest plots analysis showed that for patients with high-moderate differentiated GCLM and patients with liver metastasis located in the left liver, the overall survival rate of patients undergoing radical surgery plus systemic treatment was better than patients undergoing palliative surgery plus systemic treatment ( hazard ratio=0.21, 0.42, 95% confidence interval as 0.09-0.48, 0.23-0.78, P<0.05). Conclusions:Compared to systemic therapy alone, both radical and palliative surgery plus systemic therapy can improve the pro-gnosis of patients with initially resectable GCLM. The larger primary gastric tumor, poorly differen-tiated tumor, larger liver metastasis, multiple hepatic metastases are independent risk factors for prognosis of patients with initial resectable GCLM and immunotherapy or targeted therapy, the treatment modality of radical or palliative surgery plus systemic therapy are independent protective factors for prognosis of patients with initially resectable GCLM.

To evaluate the effectiveness and safety of implantable D-shant atrial shunt device in patients with severe pulmonary arterial hypertension(PAH)and right heart failure.A 53-year-old female patient diagnosed with severe idiopathic PAH and right heart failure,her WHO FC grade was Ⅳ.The right heart catheter and implantation of D-shant atrial shunt device were performed under local anesthesia on November 30,2021.A 6 mm×4 cm peripheral artery balloon was selected to dilate the atrial septum and a D-shant atrial shunt device with a fixed 4 mm diameter orifice was implanted into the heart.The clinical symptoms and hemodynamics of the patient was improved after the intervention.Implantation of atrial shunt device as a palliative therapy to established a right to left shunt is another strategy for treating patients with severe PAH in late period,which has good effectiveness and safety.It could be the last replacement therapy to improve symptoms and prolonged lives to drug resistant and severe PAH patients.

Objective:To examine the impact of varied surgical treatment strategies on the prognosis of patients with initial resectable gastric cancer liver metastases (IR-GCLM).Methods:This is a retrospective cohort study. Employing a retrospective cohort design, the study selected clinicopathological data from the national multi-center retrospective cohort study database, focusing on 282 patients with IR-GCLM who underwent surgical intervention between January 2010 and December 2019. There were 231 males and 51 males, aging ( M(IQR)) 61 (14) years (range: 27 to 80 years). These patients were stratified into radical and palliative treatment groups based on treatment decisions. Survival curves were generated using the Kaplan-Meier method and distinctions in survival rates were assessed using the Log-rank test. The Cox risk regression model evaluated HR for various factors, controlling for confounders through multivariate analysis to comprehensively evaluate the influence of surgery on the prognosis of IR-GCLM patients. A restricted cubic spline Cox proportional hazard model assessed and delineated intricate associations between measured variables and prognosis. At the same time, the X-tile served as an auxiliary tool to identify critical thresholds in the survival analysis for IR-GCLM patients. Subgroup analysis was then conducted to identify potential beneficiary populations in different surgical treatments. Results:(1) The radical group comprised 118 patients, all undergoing R0 resection or local physical therapy of primary and metastatic lesions. The palliative group comprised 164 patients, with 52 cases undergoing palliative resections for gastric primary tumors and liver metastases, 56 cases undergoing radical resections for gastric primary tumors only, 45 cases undergoing palliative resections for gastric primary tumors, and 11 cases receiving palliative treatments for liver metastases. A statistically significant distinction was observed between the groups regarding the site and the number of liver metastases (both P<0.05). (2) The median overall survival (OS) of the 282 patients was 22.7 months (95% CI: 17.8 to 27.6 months), with 1-year and 3-year OS rates were 65.4% and 35.6%, respectively. The 1-year OS rates for patients in the radical surgical group and palliative surgical group were 68.3% and 63.1%, while the corresponding 3-year OS rates were 42.2% and 29.9%, respectively. A comparison of OS between the two groups showed no statistically significant difference ( P=0.254). Further analysis indicated that patients undergoing palliative gastric cancer resection alone had a significantly worse prognosis compared to other surgical options ( HR=1.98, 95% CI: 1.21 to 3.24, P=0.006). (3) The size of the primary gastric tumor significantly influenced the patients′ prognosis ( HR=2.01, 95% CI: 1.45 to 2.79, P<0.01), with HR showing a progressively increasing trend as tumor size increased. (4) Subgroup analysis indicates that radical treatment may be more effective compared to palliative treatment in the following specific cases: well/moderately differentiated tumors ( HR=2.84, 95% CI 1.49 to 5.41, P=0.001), and patients with liver metastases located in the left lobe of the liver ( HR=2.06, 95% CI 1.19 to 3.57, P=0.010). Conclusions:In patients with IR-GCLM, radical surgery did not produce a significant improvement in the overall prognosis compared to palliative surgery. However, within specific patient subgroups (well/moderately differentiated tumors, and patients with liver metastases located in the left lobe of the liver), radical treatment can significantly improve prognosis compared to palliative approaches.

This study was aimed at analyzing the genomic characteristics of Salmonella typhimurium(1,4,[5],12:i:1,2)in Urumqi from 2018 to 2021,to provide evidence for the monitoring of this serotype and handling of public health emergen-cies.A total of 26 Salmonella typhimurium isolates were obtained from the feces of people with diarrhea in Urumqi.Whole-genome sequencing(WGS)combined with bioinformatic analysis was used to predict serovars,MLST types,plasmid repli-cons,antimicrobial resistance genes,and virulence genes;in addition phylogenomic analysis based on genome-wide single nucleotide polymorphisms(wgSNPs)was conducted to determine the epidemiological relatedness among isolates.A total of 47 resistance genes representing ten categories were de-tected with a high prevalence,including aac(6')-Iaa(100％),blaTEM-1B(30.8％),tet(A)(42.3％),qnrS1(30.8％),and sul3(23.1％),encoding resistance to aminoglycosides,β-lac-tams,tetracyclines,quinolones,and sulfa,in addition to chro-mosomic mutations affecting the gyrA gene.Moreover,12 plasmids were detected,among which IncFIB(S)and IncFII(S)(34.6％)were dominant.The differences in virulence genes a-mong strains isolated in different periods were reflected primarily in the typical virulence genes associated with Salmonella vir-ulence mechanisms.In addition,cgMLST indicated that the dominant type of Salmonella typhimurium was cgST36414,con-tainning 10 strains.Moreover,wgSNP analysis indicated that Salmonella typhimurium isolates in Urumqi were consistent with the epidemic trends in 15 provinces and cities in China and also showed local evolution.Salmonella typhimurium isolates in Urumqi frequently carried a variety of resistance genes and plasmid replicons,which are key in the dissemination and evolution of drug resistance.Close communication links may exist with various sources of flora in the food chain,thus posing severe chal-lenges in public health monitoring and prevention.Therefore,the construction of the laboratory routine monitoring network based on internet information systems should be strengthened to improve the timeliness of monitoring and limit the spread of multidrug-resistant strains.

This study was aimed at analyzing the genomic characteristics of Salmonella typhimurium(1,4,[5],12:i:1,2)in Urumqi from 2018 to 2021,to provide evidence for the monitoring of this serotype and handling of public health emergen-cies.A total of 26 Salmonella typhimurium isolates were obtained from the feces of people with diarrhea in Urumqi.Whole-genome sequencing(WGS)combined with bioinformatic analysis was used to predict serovars,MLST types,plasmid repli-cons,antimicrobial resistance genes,and virulence genes;in addition phylogenomic analysis based on genome-wide single nucleotide polymorphisms(wgSNPs)was conducted to determine the epidemiological relatedness among isolates.A total of 47 resistance genes representing ten categories were de-tected with a high prevalence,including aac(6')-Iaa(100％),blaTEM-1B(30.8％),tet(A)(42.3％),qnrS1(30.8％),and sul3(23.1％),encoding resistance to aminoglycosides,β-lac-tams,tetracyclines,quinolones,and sulfa,in addition to chro-mosomic mutations affecting the gyrA gene.Moreover,12 plasmids were detected,among which IncFIB(S)and IncFII(S)(34.6％)were dominant.The differences in virulence genes a-mong strains isolated in different periods were reflected primarily in the typical virulence genes associated with Salmonella vir-ulence mechanisms.In addition,cgMLST indicated that the dominant type of Salmonella typhimurium was cgST36414,con-tainning 10 strains.Moreover,wgSNP analysis indicated that Salmonella typhimurium isolates in Urumqi were consistent with the epidemic trends in 15 provinces and cities in China and also showed local evolution.Salmonella typhimurium isolates in Urumqi frequently carried a variety of resistance genes and plasmid replicons,which are key in the dissemination and evolution of drug resistance.Close communication links may exist with various sources of flora in the food chain,thus posing severe chal-lenges in public health monitoring and prevention.Therefore,the construction of the laboratory routine monitoring network based on internet information systems should be strengthened to improve the timeliness of monitoring and limit the spread of multidrug-resistant strains.

Objective To observe the effect of cervical degenerative change on the expression of vascular endothelial growth factor(VEGF)and vascular endothelial growth factor receptor-2(VEGFR-2).Methods The C3 to C7 segments of bilateral healthy cervical vertebrae of adult cadavers were taken as the control group,and the C3 to C7 segments of bilateral degenerative cervical vertebrae of adult cadavers were taken as the experimental group.The expression changes of VEGF and VEGFR-2 of the two groups were observed and analyzed by immunohistochemistry,immunofluorescence staining and real-time quantitative PCR.Results The protein and mRNA expressions of VEGF and VEGFR-2 in the experimental group were higher than those in the control group,with statistically significant differences(P<0.05).Conclusion Cervical Luschka joint degenerative change significantly up-regulates the expression of VEGF and VEGFR-2,which is closely related to the microenvironmental changes around the Luschka joint caused by degeneration of joint-like structure.

OBJECTIVES: To investigate the incidence of extrauterine growth retardation (EUGR) and its risk factors in very preterm infants (VPIs) during hospitalization in China. METHODS: A prospective multicenter study was performed on the medical data of 2 514 VPIs who were hospitalized in the department of neonatology in 28 hospitals from 7 areas of China between September 2019 and December 2020. According to the presence or absence of EUGR based on the evaluation of body weight at the corrected gestational age of 36 weeks or at discharge, the VPIs were classified to two groups: EUGR group (n=1 189) and non-EUGR (n=1 325). The clinical features were compared between the two groups, and the incidence of EUGR and risk factors for EUGR were examined. RESULTS: The incidence of EUGR was 47.30% (1 189/2 514) evaluated by weight. The multivariate logistic regression analysis showed that higher weight growth velocity after regaining birth weight and higher cumulative calorie intake during the first week of hospitalization were protective factors against EUGR (P<0.05), while small-for-gestational-age birth, prolonged time to the initiation of total enteral feeding, prolonged cumulative fasting time, lower breast milk intake before starting human milk fortifiers, prolonged time to the initiation of full fortified feeding, and moderate-to-severe bronchopulmonary dysplasia were risk factors for EUGR (P<0.05). CONCLUSIONS It is crucial to reduce the incidence of EUGR by achieving total enteral feeding as early as possible, strengthening breastfeeding, increasing calorie intake in the first week after birth, improving the velocity of weight gain, and preventing moderate-severe bronchopulmonary dysplasia in VPIs.
Female ; Fetal Growth Retardation ; Gestational Age ; Hospitalization ; Humans ; Incidence ; Infant ; Infant, Newborn ; Infant, Premature ; Infant, Very Low Birth Weight ; Prospective Studies ; Risk Factors