Objective To investigate the effects of sodium arsenite (NaAsO2) on cell survival circumstance,reactive oxygen species (ROS) and cell apoptosis in human normal hepatic cells (L-02).Methods L-02 cells were exposed to different doses of NaAsO2 (0,50,100,150 μmol/L) for 24 h.MTT assay was used to detect the survival of L-02 cells,and flow cytometry (FCM) was used to detect the ROS levels and the early (Q4),late (Q2) apoptosis of L-02 cells.Results Cell survival rate:cell survival rate was compared between groups,the difference was statistically significant (F =350.51,P ＜ 0.05),the cell survival rates of 50,100 and 150 μmol/L NaAsO2 groups [(87.30 ± 3.74)％,(49.03 ± 4.72)％,(13.44 ± 4.01)％] were significantly lower than that of the control group [(100.00 ± 0.00)％,all P ＜ 0.05];compared with 50 μmol/L NaAsO2 group,the cell survival rates of 100 and 150 μmol/L NaAsO2 groups were significantly decreased (all P ＜ 0.05);compared with 100 μmol/L NaAsO2 group,the cell survival rate of 150 μmol/L NaAsO2 group was significantly decreased (P ＜ 0.05).The ROS levels:ROS levels were compared between groups,the difference was statistically significant (F =407.78,P ＜ 0.05),the ROS levels of 100 and 150 μ mol/L NaAsO2 groups (3 212.00 ± 221.93,5 521.33 ± 179.63) were significantly higher than that of the control group (1 691.67 ± 73.98,all P＜ 0.05);compared with 50 μmol/L NaAsO2 group (1 927.67 ± 62.45),the ROS levels of 100 and 150 μmol/L NaAsO2 groups were significantly increased (all P ＜ 0.05);compared with 100 μmol/L NaAsO2 group,the ROS level of 150 μ mol/L NaAsO2 group was significantly increased (P ＜ 0.05).Cell apoptosis:cell apoptosis rates of Q2,Q4 and Q2 + Q4 were compared between groups,the differences were statistically significant (F =256.84,26.53,63.89,all P ＜ 0.05);excecpt the cell apoptosis rate of Q4 in 50 μ mol/L NaAsO2 group [(5.43 ± 0.57) ％],the cell apoptosis rates of Q2 [(5.67 ± 0.21)％] and Q2 + Q4 [(11.10 ± 0.40) ％] in 50 μ mol/L NaAsO2 group,the cell apoptosis rates of Q2 [(13.60 ± 0.79) ％],Q4 [(7.37 ± 2.01) ％] and Q2 + Q4 [(20.97 ± 2.38) ％] in 100 μmol/L NaAsO2 group,the cell apoptosis rate of Q2 [(13.47 ± 0.78) ％],Q4 [(16.97 ± 3.45) ％] and Q2 + Q4 [(30.43 ± 3.84) ％] in 150 μmol/L NaAsO2 group were significantly higher than those of the control group [Q2:(3.47 ± 0.12) ％,Q4:(2.90 ± 0.90) ％,Q2 + Q4:(6.37 ± 1.00) ％,all P ＜ 0.05];compared with 50 μmol/L NaAsO2 group,the cell apoptosis rates of Q2,Q4 and Q2 + Q4 in 100 and 150 μmol/L NaAsO2 groups were increased,except the cell apoptosis rate of Q4 in 100 μ mol/L NaAsO2 group,the differences were statistically significant (all P＜0.05);the cell apoptosis rates of Q4 and Q2 + Q4 in 150 μmol/L NaAsO2 group compared with 100 μmol/L NaAsO2 group were significantly increased (all P ＜ 0.05).Conclusions NaAsO2 can induce L-02 cells to increase ROS levels,and inhibit L-02 cell proliferation.In addition,NaAsO2 can induce early apoptosis and late apoptosis in L-02 cells.

Objective To investigate the changes of serum leptin and bone speed of sound (SOS) with gestational age (GA) and relationship between leptin and bone SOS in appropriate-for-gestational-age (AGA) neonates. Methods A total of 65 AGA neonates were recruited and divided into three groups according to their gestational age:preterm infant (GA 31-34 w, 14 cases), late preterm infant (GA 34-37 w, 13 cases), and full-term infant (GA≥37 w, 38 cases). Anthropometric parameters, including birth weight, length, leg length, skin fold thickness were measured in all the subjects, and the neonatal nutritional status and body fat content were evaluated by Ponderal Index (PI) and Weststrate equation (F%) respectively. Serum leptin concentration and tibial SOS were measured within 7 days after birth. Results There were signiifcant differences in GA (F=140.199, P<0.001), birth weight (F=47.042, P<0.001), birth length (F=46.877, P<0.001), leg length (F=17.543, P<0.001), PI (F=11.898, P<0.001) and F%( F=21.955, P<0.001) among three groups. Serum leptin and tibial SOS were signiifcantly different among these groups ( F=49.724, 20.052 respectively, P<0.001), and both of them were positively correlated with gestational age and birth weight (P<0.01). In addition, leptin was positively correlated with tibial SOS, but the correlation disappeared after adjustment for GA and anthropometry. According to the multivariate forward stepwise regression analysis, tibial SOS was found to be signiifcantly positively associated with gestational age and birth weight in the three groups. Conclusions Both bone SOS and serum leptin are signiifcantly correlated with gestational age and birth weight in AGA neonates, and leptin is related with but not the independent direct predictor of bone SOS.

Objective To investigate the effects of sodium arsenite (NaAsO2) on the expressions of Cyclin D1 and Cyclin dependent kinase 4 (CDK4) in human normal liver cells (L-02).Methods L-02 cells were exposed to different doses of NaAsO2 (0,50,100,150 μmol/L) for 24 h,flow cytometry was used to detect the cell cycle,real time quantitative PCR and Western blotting were used to detect the Cyclin D1,CDK4 mRNA and protein expression.Results Cell cycle detection:compared with the control group G0-G1 phase [(60.33 ± 0.40)％],except 50 μmol/L NaAsO2 group [(54.58 ± 0.40)％],the numbers of cells in 100 and 150 μmol/L NaAsO2 groups [(64.60 ± 0.62)％,(83.13 ± 0.25)％] were increased,the differences were statistically significant (all P ＜ 0.05);cell proportion of S phase in the control group,50,100 and 150 μmol/L NaAsO2 groups [(34.35 ± 0.30)％,(29.89 ± 0.32)％,(29.50 ± 0.44)％,(11.93 ± 0.12)％] were decreased,the differences were statistically significant (all P ＜ 0.05);cell proportion of G2-M phase was compared between the control group,50,100 and 150 μmol/L NaAsO2 groups [(5.32 ± 0.11)％,(15.54 ± 0.14)％,(5.90 ± 0.20)％,(4.93 ± 0.15)％],the difference was statistically significant (F =908.359,P ＜ 0.05).Cyclin D1 and CDK4 detection:the expressions of Cyclin D1 mRNA (0.48 ± 0.17,1.00 ± 0.31,1.00 ± 0.21,2.06 ± 0.53) and protein (0.65 ± 0.02,0.64 ± 0.05,0.71 ± 0.10,0.84 ± 0.05) were compared betwee the control group,50,100 and 150 μmol/L NaAsO2 groups,the differences were statistically significant (F =167.886,46.575,all P ＜ 0.05);the expressions of CDK4 mRNA (1.04 ± 0.19,1.00 ± 0.21,1.29 ± 0.22,2.31 ± 0.31) and protein (0.67 ± 0.04,0.74 ± 0.03,0.83 ± 0.07,0.94 ± 0.04) were compared betwee the control group,50,100 and 150 μ mol/L NaAsO2 groups,the differences were statistically significant (F =95.171,145.848,all P ＜ 0.05).Conclusions Treatment of L-02 cells with NaAsO2 has changed the expressions of Cyclin D1,CDK4 mRNA and protein,which leads to L-02 cell cycle arrested at G0-G1 phase,ultimately leads to cell damage.

Objective: To investigate the expression of gluconeogenic enzymes phosphoenolpyruvate carboxykinase (PEPCK) and G-6-Pase mRNA of hepatic tissue in rats with intrauterine growth retardation (IUGR) and to explore the molecular mechanism of insulin resistance in IUGR rats. Methods: Pregnant rats were randomly divided into 2 groups: a normal group and a model group. hTe normal group were fed with 21% protein forage and the model group with 10% low protein forage to obtain IUGR pup rats. hTe pup rats were introduced to the normal group and the IUGR group prospectively. At 1, 3 and 8 weeks, the body weight, blood glucose, insulin concentration andinsulin resistance index of the pup rats were measured. Expression of PEPCK and G-6-Pase mRNA were detected by RT-PCR. Results: The birth weight of the IUGR group was significantly lower than that of the normal group (P<0.001). The weight of the IUGR group was still lower than that of the normal group at 1, 3 and 8 weeks. There was no significant difference in the blood glucose, insulin level and insulin resistance index between the 2 groups (P>0.05). The hepatic expression of PEPCK and G-6-Pase mRNA in the IUGR group was significantly higher than that of the normal group at 1, 3 and 8 weeks (P<0.01). Conclusion: The significantly increased expression of PEPCK and G-6-Pase mRNA of hepatic tissue in IUGR rats may increase gluconeogenesis, which is probably one of the molecular mechanisms of insulin resistance and diabetes in IUGR.

Objective: To understand the sanitation status of rural primary and secondary schools during 2015-2019, and provide data support for the formulation of environmental sanitation policies for schools in rural areas of Guiyang. Methods: According to the requirements of the Work Plan for the Rural Environmental Sanitation Monitoring Project in Guiyang City from 2015-2019, 145 rural schools in Guiyang were selected by stratified random sampling method, including 75 elementary schools and 70 junior high schools. Through on site inspection and questionnaire survey, information regarding school basic situation, drinking water for students, water supply and toilet sanitation in school. Results: Students drinking water was mainly bottled water or water from a water purifier, the proportional rate increased from 37.9% to 72.4%; water supply in the school was mainly from village water plant, from 69.0% to 93.1%; the proportion of schools with independent public toilets and toilets in dormitory buildings ranged from 65.6% to 100.0%, the proportion of schools with toilets in teaching buildings was less than 60.0%, but the penetration rate of sanitary toilets in independent public toilets, teaching buildings and dormitory buildings were more than 80.0%. Qualified rate of squatting in the men s toilet fluctuated between 93.1% and 100.0%. Qualified rate of the squatting in the women s toilet had increased from 44.8% to 65.5%. Proportion of school toilets guarded by specific staff decreased from 31.0% to 27.6%. The proportion of soap increased from 20.7% to 58.6%, the difference was statistically significant ( χ 2=21.27, P =0.01). Conclusion During 2015-2019, the environmental sanitation in rural areas of Guiyang was acceptable, with students drinking water, school water supply and sanitary toilets moderately improved. Toilets in the teaching building and women s toilet squatting numbers need to be increased. School toilets managed by specific personnel, as well as good hygiene habits education promotion are encouraged.

Objective To study the effects of human milk on feeding intolerance, infant growth and development, complications during hospitalization and length of hospital stay in very/extremely low birth weight (VLBW/ELBW) preterm infants. Methods VLBW/ELBW preterm infants admitted to the Division of Neonatology, Children's Medical Center of the Second Xiangya Hospital from May 2015 to April 2018 were enrolled in this retrospective study and were assigned into two groups: human milk group (human milk accounted for at least 50% of total enteral feeding during hospitalization) and formula group (exclusive formula feeding due to breastfeeding contraindication or insufficient human milk supply). Feeding intolerance, neonatal growth, complications and length of hospital stay were compared between the two groups using independent sample t-test, Mann-Whitney U test and Chi-square test (or Fisher's exact probability test). Results A total of 113 VLBW/ELBW infants were enrolled consisting of 52 in the human milk group and 61 in the formula group. The starting time of enteral feeding, duration of minimal enteral feeding and incidence of feeding intolerance were similar between the two groups (all P>0.05). The increasing rate of milk volume was (8.4±1.6) ml/(kg·d) in the human milk group and (7.6±1.4) ml/(kg·d) in the formula group (t=2.853, P<0.05). The length of parenteral nutrition of the human milk group was shorter than that of the formula group [(29.3±7.6) vs (33.0±7.9) d, t=－2.570, P<0.05], so was the time to full enteral feeding [(30.0±7.8) vs (34.9±8.8) d, t=－3.076, P<0.05]. No significant difference was found in the average weight gain, increment in head circumference or body length, the length of regaining birth weight, or the incidence of extrauterine growth restriction between the two groups (all P>0.05). The incidence of neonatal necrotizing enterocolitis (NEC) in the human milk group was lower than that of the formula group [1.9% (1/52) vs 11.5% (7/61), χ2=3.894, P<0.05]. No statistical difference in the incidence of sepsis, cholestasis, anemia, bronchopulmonary dysplasia (BPD), retinopathy of prematurity or periventricular leukomalacia was observed between the two groups (all P>0.05). There were 14 cases (26.9%) of BPD in the human milk group, of which eight were mild and six moderate. While in the formula group, 24 cases (39.3%) had BPD and among them, four, 18 and two infants were mild, moderate and severe BPD, respectively. BPD cases in the human milk group were less severe than those in the formula group (U=－2.645, P<0.05). The length of hospital stay of the human milk group was shorter than that of the formula group [(47.5±14.8) vs (53.9±16.3) d, t= － 2.129, P<0.05)]. Conclusions Human milk for VLBW/ELBW infants may shorten the time to full enteral feeding and the length of hospital stay, reduce the incidence of NEC, decrease the severity of BPD. VLBW/ELBW infants fed with fortified human milk have similar growth rate as those fed with formula milk.