Objective:To compare the protective effects of the static cold storage (SCS) and normothermic machine perfusion (NMP) on the skeletal muscle of the amputated limbs of pigs.Methods:Four Landrace pigs were selected, from which eight limbs were amputated and divided into SCS group ( n=5) and NMP group ( n=3) according to the random number table method. After blood collection from the carotid artery, an amputated limb model was established by amputating the limbs at the scapulohumeral joints. The limbs in the SCS group were wrapped in sterile cloth and stored at 4 ℃ for 24 hours. In the NMP group, the limbs were mechanically perfused with a red blood cell-containing perfusion fluid at 37 ℃ for 24 hours, with 70% of the perfusion fluid replaced every 6 hours. Before the experiment, cross-matching tests with the saline medium were conducted between donor and recipient pigs to evaluate blood coagulation and blood safety in the NMP group. An allogeneic red blood cell perfusion fluid was prepared and the levels of pH, Na +, K +, Cl -, Ca 2+, glucose (Glu), hematocrit (Hct), lactic acid (Lac) and osmotic pressure of the perfusion fluid were measured. At 0, 6, 12, 18, and 24 hours after perfusion, the skin temperature and oxyhemoglobin saturation (SaO 2) levels in the NMP group were monitored and the levels of pH, Glu, creatine kinase (Ck), K +, Ca 2+, and Na +levels of the perfusion fluid were analyzed to evaluate the metabolism of the skeletal muscle in the amputated limbs. The mean intercellular distance and apoptosis index of the myocytes were quantitatively analyzed and histopathological changes were observed by performing HE staining and TUNEL staining on the skeletal muscle of the amputated limbs in both groups at 0 and 24 hours after perfusion. After perfusion was ended, the weight gain rate and swelling degree of the amputated limbs were compared between the two groups and the overall state of the amputated limbs was evaluated. Results:The result of the cross-matching test between donor and recipient pig blood was negative. The parameters in the prepared red blood cell-containing perfusion fluid generally maintained within a normal range: pH 7.38±0.04, Na + concentration (138.30±4.48)mmol/L, K + concentration (3.50±0.26)mmol/L, Glu concentration (6.11±2.08)mmol/L, and osmotic pressure (305.67±3.79)mmol/L. However, slightly higher Cl - and Ca 2+ concentrations [(118.34±12.00)mmol/L and (2.00±0.15)mmol/L] and lower Hct and lactate concentrations [0.30±0.03 and (1.54±0.38)mmol/L] were detected when compared with the reference range. During the perfusion, the average skin temperature of the amputated limbs in the NMP group was (36.13±0.98)℃, with the skin temperatures at 6, 12, 18, and 24 hours after perfusion being significantly higher than that at 0 hour ( P<0.01), while no significant difference among the skin temperatures at 6, 12, 18, and 24 hours after perfusion was observed ( P>0.05). The SaO 2 levels in the skin of the amputated limbs in the NMP group averaged over 95%, which showed no significant difference at 0, 12, 18, and 24 hours after perfusion ( P>0.05), while a significant elevation was observed at 6 hours compared with that at 0 hour ( P<0.05). There were no significant differences in pH, Glu, Na +, and Ca 2+ levels in the NMP group at 0, 6, 12, 18, and 24 hours after perfusion ( P>0.05), while the Ck levels at 18 and 24 hours were both significantly higher than that at 6 hours after perfusion ( P<0.05), and the Ck levels at 6, 12, 18, and 24 hours were all significantly higher than that at 0 hour ( P<0.05). The K + level progressively increased with the perfusion time, with significant elevations at 18 and 24 hours after perfusion compared with that at 0 hour ( P<0.05). HE staining revealed well-preserved muscle fiber continuity and regular arrangement in the NMP group and the SCS group at 0 hour, with an intercellular distance of (8.95±0.60)μm. At 24 hours, the NMP group exhibited slight skeletal muscle fiber rupture and swelling, with a slightly increased intercellular distance of (14.75±0.90)μm, significantly greater than that at 0 hour ( P<0.01). At 24 hours, the SCS group showed marked skeletal muscle fiber rupture and swelling, with a significantly increased intercellular distance of (23.51±1.49)μm, significantly larger than those at 0 hour in the same group and at 24 hours in the NMP group ( P<0.01). TUNEL immunofluorescence staining indicated a tiny amount of apoptotic cells in the skeletal muscle in both groups at 0 hour, with an apoptotic index of (4.26±1.62)%. There was a small number of apoptotic cells in the skeletal muscle in the NMP group at 24 hours, with an apoptotic index of (25.94±2.69)%, significantly larger than that in the same group at 0 hour ( P<0.01). The SCS group exhibited a large number of apoptotic cells at 24 hours, with an apoptotic index of (62.97±3.22)%, significantly larger than those at 0 hour in the same group and at 24 hours in the NMP group ( P<0.01). In comparison with the SCS group at 24 hours, the amputated limbs in the NMP group showed red color in the appearance, no symptoms of ischemic muscle contracture and good joint movement despite slight edema in the subcutaneous layer. At 24 hours, the weight gain rate of the amputated limbs was (15.82±0.89)% in the NMP group, significantly higher than (0.97±0.28)% in the SCS group ( P<0.01). Conclusion:Compared with SCS, NMP with the red blood cell-containing perfusion fluid prepared with the allogeneic blood for the amputated limbs of pigs can alleviate the ischemic injury of the muscle fibers and inhibit the apoptosis of the muscle cells by sustaining stable energy and oxygen supply and balancing ion homeostasis and pH of the perfusion fluid.

Objective:To compare the protective effects of the static cold storage (SCS) and normothermic machine perfusion (NMP) on the skeletal muscle of the amputated limbs of pigs.Methods:Four Landrace pigs were selected, from which eight limbs were amputated and divided into SCS group ( n=5) and NMP group ( n=3) according to the random number table method. After blood collection from the carotid artery, an amputated limb model was established by amputating the limbs at the scapulohumeral joints. The limbs in the SCS group were wrapped in sterile cloth and stored at 4 ℃ for 24 hours. In the NMP group, the limbs were mechanically perfused with a red blood cell-containing perfusion fluid at 37 ℃ for 24 hours, with 70% of the perfusion fluid replaced every 6 hours. Before the experiment, cross-matching tests with the saline medium were conducted between donor and recipient pigs to evaluate blood coagulation and blood safety in the NMP group. An allogeneic red blood cell perfusion fluid was prepared and the levels of pH, Na +, K +, Cl -, Ca 2+, glucose (Glu), hematocrit (Hct), lactic acid (Lac) and osmotic pressure of the perfusion fluid were measured. At 0, 6, 12, 18, and 24 hours after perfusion, the skin temperature and oxyhemoglobin saturation (SaO 2) levels in the NMP group were monitored and the levels of pH, Glu, creatine kinase (Ck), K +, Ca 2+, and Na +levels of the perfusion fluid were analyzed to evaluate the metabolism of the skeletal muscle in the amputated limbs. The mean intercellular distance and apoptosis index of the myocytes were quantitatively analyzed and histopathological changes were observed by performing HE staining and TUNEL staining on the skeletal muscle of the amputated limbs in both groups at 0 and 24 hours after perfusion. After perfusion was ended, the weight gain rate and swelling degree of the amputated limbs were compared between the two groups and the overall state of the amputated limbs was evaluated. Results:The result of the cross-matching test between donor and recipient pig blood was negative. The parameters in the prepared red blood cell-containing perfusion fluid generally maintained within a normal range: pH 7.38±0.04, Na + concentration (138.30±4.48)mmol/L, K + concentration (3.50±0.26)mmol/L, Glu concentration (6.11±2.08)mmol/L, and osmotic pressure (305.67±3.79)mmol/L. However, slightly higher Cl - and Ca 2+ concentrations [(118.34±12.00)mmol/L and (2.00±0.15)mmol/L] and lower Hct and lactate concentrations [0.30±0.03 and (1.54±0.38)mmol/L] were detected when compared with the reference range. During the perfusion, the average skin temperature of the amputated limbs in the NMP group was (36.13±0.98)℃, with the skin temperatures at 6, 12, 18, and 24 hours after perfusion being significantly higher than that at 0 hour ( P<0.01), while no significant difference among the skin temperatures at 6, 12, 18, and 24 hours after perfusion was observed ( P>0.05). The SaO 2 levels in the skin of the amputated limbs in the NMP group averaged over 95%, which showed no significant difference at 0, 12, 18, and 24 hours after perfusion ( P>0.05), while a significant elevation was observed at 6 hours compared with that at 0 hour ( P<0.05). There were no significant differences in pH, Glu, Na +, and Ca 2+ levels in the NMP group at 0, 6, 12, 18, and 24 hours after perfusion ( P>0.05), while the Ck levels at 18 and 24 hours were both significantly higher than that at 6 hours after perfusion ( P<0.05), and the Ck levels at 6, 12, 18, and 24 hours were all significantly higher than that at 0 hour ( P<0.05). The K + level progressively increased with the perfusion time, with significant elevations at 18 and 24 hours after perfusion compared with that at 0 hour ( P<0.05). HE staining revealed well-preserved muscle fiber continuity and regular arrangement in the NMP group and the SCS group at 0 hour, with an intercellular distance of (8.95±0.60)μm. At 24 hours, the NMP group exhibited slight skeletal muscle fiber rupture and swelling, with a slightly increased intercellular distance of (14.75±0.90)μm, significantly greater than that at 0 hour ( P<0.01). At 24 hours, the SCS group showed marked skeletal muscle fiber rupture and swelling, with a significantly increased intercellular distance of (23.51±1.49)μm, significantly larger than those at 0 hour in the same group and at 24 hours in the NMP group ( P<0.01). TUNEL immunofluorescence staining indicated a tiny amount of apoptotic cells in the skeletal muscle in both groups at 0 hour, with an apoptotic index of (4.26±1.62)%. There was a small number of apoptotic cells in the skeletal muscle in the NMP group at 24 hours, with an apoptotic index of (25.94±2.69)%, significantly larger than that in the same group at 0 hour ( P<0.01). The SCS group exhibited a large number of apoptotic cells at 24 hours, with an apoptotic index of (62.97±3.22)%, significantly larger than those at 0 hour in the same group and at 24 hours in the NMP group ( P<0.01). In comparison with the SCS group at 24 hours, the amputated limbs in the NMP group showed red color in the appearance, no symptoms of ischemic muscle contracture and good joint movement despite slight edema in the subcutaneous layer. At 24 hours, the weight gain rate of the amputated limbs was (15.82±0.89)% in the NMP group, significantly higher than (0.97±0.28)% in the SCS group ( P<0.01). Conclusion:Compared with SCS, NMP with the red blood cell-containing perfusion fluid prepared with the allogeneic blood for the amputated limbs of pigs can alleviate the ischemic injury of the muscle fibers and inhibit the apoptosis of the muscle cells by sustaining stable energy and oxygen supply and balancing ion homeostasis and pH of the perfusion fluid.

【Objective】 To investigate the electronic screen exposure of preschool children in Longhua District of Shenzhen, and to analyze the influencing factors. 【Methods】 A total of 25 266 children in kindergarten in Longhua District of Shenzhen were selected as study subjects. A self-designed questionnaire (completed by their guardians) was used to investigate the use of electronic products in the families of preschoolers in April 2019. 【Results】 A total of 23 407 valid questionnaires were collected in this survey, of which 12 593 (53.80%) were boys and 10 814 (46.20%) were girls; and 17 188(73.43%) children were 5 years old. Among the surveyed children, the rate of excessive exposure to electronic screens (>1h/d) was 37.72%, and 6.40% of preschool children used electronic products for more than 2 hours per day. There were statistically significant differences between the excessive exposure group and the non-excessive exposure group in gender, household registration, parents′ educational level, average monthly household income, whether exclusive electronic products,whether restriction of children′s use of electronic products, whether living with elders, only children or not, and the type of main caregiver (P<0.05). Multivariate binary Logistic regression analysis showed that girls, mothers with college education or above,not living with elders,primary caregivers being parents or nannies/others,and no exclusive electronic products were protective factors for children′s excessive exposure to electronic products(P<0.05).Non-household resident population,not-only child,and non-restriction of children′s use of electronic products were risk factors for children′s excessive exposure to electronic products(P<0.05). 【Conclusions】 The excessive use of electronic products in preschoolers is a common phenomenon in Longhua district, Shenzhen. Therefore, it is necessary to strengthen the intervention on the use time of electronic products in preschoolers, and pay more attention to the influence of family environmental factors.

At present,the treatment of non-small cell lung cancer (NSCLC) has entered the era of targeted therapy,and small molecule tyrosine kinase inhibitors are typical representatives,which have clear molecular targets and remarkable effects.But many patients without mutations are not able to benefit from them.Vascular endothelial growth factor and immune targeted therapy have become the new focus of NSCLC treatment.Inhibitors such as programmed cell death-1 and programmed cell death-ligand 1 have shown great applied potential in a series of clinical trials of NSCLC.

Objective: To study the expression of TNF-α and PCNA in human breast tissue with polyacrylamide hydrogel(PAHG) injection, and to provide the initial theory basis for its prognosis and clinical treatment. Methods: Immunohistochemistry was used to measure the expression of tumor necrosis factor α(TNF-α)and proliferating cell nuclear antigen (PCNA) in 20 normal breast tissues and 40 cases with PAHG injection, analysis was also done by HE staining. Results: ①HE staining showed that there were a large number of homogeneous amorphous gel-like injections under optical microscope. Around PAHG there were different degrees of fibrous tissue hyperplasia with or without fibrous degeneration and lots of inflammatory cells. Local foreign body giant cell reaction and ductal dilatation also can be seen around PAHG. ②The IA levels of TNF-α and PCNA in the experimental group were 3.9± 0.3 and 3.2 ± 0.2, the IA levels of TNF-α and PCNA in the control group were 1.0 ± 0.1 and 1.3 ± 0.3, the IA level in the experimental group was significantly higher than that in the control group (P=0.000). The difference was statistically significant. The positive rates of TNF-α and PCNA in the experimental group were 90% (36/40)and 85% (34/40)respectively; the positive rates of TNF-α and PCNA in the control group were 30% (6/20), 40% (8/20). The positive expression rate in the experimental group was significantly higher than that in the control group (P=0.000). The difference was statistically significant. TNF-α and PCNA has Pearson positive relevance in the changes(r=0.3, P=0.040), the difference was statistically significant. Conclusions TNF-α and PCNA are involved in the immunoreaction of mammalian breast tissue injected with polyacrylamide hydrogel, which may induce the aseptic inflammation, fibrous tissue hyperplasia and related issues through mutual influence.

Objective To investigate the role of different parenting styles plays in conduct problems of 3-years-old preschool children.Methods Participants were from 148 preschools in Longhua Shenzhen,China.A structured questionnaire covering family demographic characteristics,Conners' Parent Symptom Questionnaire and Egna Minnen Betraffande Uppfostran-Parents (EMBU-P) were conducted among primary caregivers of each child.There were 9289 valid participants in the analysis and logistic regression was used to assess the relationship between three dimensions of parenting (rejection,emotional warmth and control/overprotection) and conduct problems.Results After allowing for certain confounders,parental rejection (OR =1.17,P＜0.01) and control/overprotection (OR =1.03,P＜0.01) was positively associated with conduct problems and emotional warmth was negatively related to conduct problems (OR=0.98,P＜0.01).Stratified analysis showed a significant relationship between conduct problems and both parents' rejection (OR father=1.16,P＜0.01;OR motber=1.17,P＜0.01),father's emotional warmth (OR=0.96,P＜0.01) and mother's control/overprotection (OR=1.04,P＜0.01).This relationship did not vary between boys and girls and between single and not single children.Conclusion Influence of parenting should be taken into consideration in the prevention and intervention of conduct problems.

[ ABSTRACT] AIM:To investigate the effect of hydrogen sulfide ( H2 S) on airway inflammation induced by ozone (O3) exposure and its mechanisms.METHODS:C57BL/6 mice (n=32) were randomly divided into control group, O3 group, NaHS+O3 group and NaHS group.The mice in O3 group and O3 +NaHS group were exposed to 2.14 mg/m3 O3 for 3 h on days 1, 3 and 5, while the mice in control group and NaHS group were exposed to filtered air .NaHS (14μmol/kg) was administered intraperitoneally to the mice in NaHS group and O 3 +NaHS group 30 min before each exposure .After the last exposure for 24 h, the airway responsiveness was determined , and bronchoalveolar lavage fluid ( BALF) was collected for counting inflammatory cells and measuring total protein concentration .The lung tissues were collected for observing the morphological changes with HE staining .The levels of interleukin-6 ( IL-6 ) , interleukin-8 ( IL-8 ) , malondialdehyde ( MDA) and NF-κB p65 protein in the lungs were determined .RESULTS: Compared with control group , the airway re-sponsiveness, inflammatory cells, protein concentration, inflammation score, levels of IL-6, IL-8, MDA and NF-κB p65 in O3 group increased significantly , but these in NaHS+O3 group decreased compared with O 3 group.CONCLUSION: The present findings suggest that H 2 S attenuates O3 induced airway inflammation by inhibiting NF-κB expression and preventing lipid peroxidation .

Objective To explore the addictive tendency of internet and its influence factors among adolescents in Longhua District of Shenzhen. Methods A total of 6552 Students were selected from Longhua District of Shenzhen us?ing randomly stratified cluster sampling method. They were inquired about their gender, grade, family type, behaviors of surfing internet, risk behaviors, and internet addiction tendency with a self-report structured questionnaire and the adoles?cent pathological internet use scale (APIUS). Results The prevalence of addictive tendency of internet was 9.0%(590/6552) among adolescents in Longhua District of Shenzhen. Multiple logistic regression analysis indicated that the addic?tive tendency of internet was significantly and positively associated with male (OR=1.32, P<0.05), living in Minzhi area (OR=1.66, P<0.01), secondary school stage (OR=1.62, P<0.01), uncomplete family type (OR=1.49, P<0.01), surfing in cy?bercafé frequently (OR=2.00, P<0.01), compared with surfing 0~2 h/d, surfing 2~4 h/d (OR=1.92,P<0.01), 4~5 h/d (OR=2.97, P<0.01) or more than 6 h/d (OR=4.90, P<0.01), playing games (OR=3.27, P<0.01), chatting (OR=2.80, P<0.01) or having other kinds of entertaining (OR=2.80, P<0.01), and having risky behaviors (OR=2.39, P<0.01). Conclusion The addictive tendency of internet is affected by multiple factors among adolescents in Longhua District of Shenzhen. There?fore, comprehensive intervention measures shall be used to regulate adolescents habits of using internet and prevent them from the internet addiction.

BACKGROUND:Hyperbaric oxygen (HBO) therapy can aleviate the skin flap congestion by improving the angiogenesis and increasing the oxygen content of blood in skin flaps. Although the HBO therapy ability to increase flap survival has been wel described, the research on the application of HBO pretreatment in skin flap transplantation does not arouse adequate concern.
OBJECTIVE: To investigate the effect of HBO pretreatment on early-stage flap congestion in the rat model of over-length dorsal random skin flaps.
METHODS: Thirty-six SD rats were randomly divided into control group (n=12), HBO pretreatment group (n=12) and HBO treatment group (n=12). Rats in the HBO pretreatment group received 4 days of HBO therapy prior to transplantation, once a day. Rats in the HBO treatment group received 4 days of HBO therapy after transplantation. Rats in the control group were raised in the normal conditions after flap transplantation. At postoperative days 3 and 5, rats were sacrificed and the samples were colected. The inflammation of flap tissues was detected using hematoxylin-eosin staining. The expression of vascular endothelial growth factor and transforming growth factor-β was analyzed by immunohistochemistry staining. The flap survival rate was calculated at postoperative day 5.
RESULTS AND CONCLUSION:The flap survival area of the HBO pretreatment group and HBO treatment group was larger than that of the control group (P < 0.05). At postoperative days 3 and 5, the expression levels of vascular endothelial growth factor and transforming growth factor-β in the flap tissue were higher in the HBO pretreatment group and HBO treatment group than the control group (P < 0.05). However, there was no significant difference in the flap survival area and the expression of vascular endothelial growth factor and transforming growth factor-β between HBO pretreatment and HBO treatment groups (P > 0.05). HBO pretreatment can increase the expression of vascular endothelial growth factor and transforming growth factor-β and promotes angiogenesis in random pattern flaps,thereby improving skin flap survival.

Objective To explore the interaction between passive smoking and folic acid supplement during pregnancy on children autism spectrum disorder (ASD) behaviors.Methods Children aged about 3 years were enrolled at kindergarten entrance in Longhua district of Shenzhen in 2014.Self-administered questionnaires were completed by their primary caregivers and the information about children' s age,gender,history of preterm birth and low birth weight,parents' education level,parents' reproductive age and family income were collected.The children ASD behaviors were assessed with Autism Behavior Checklist (ABC).According to the cut point of ABC,the children were divided into normal group with score less than 31,sub-clinical group with score ranging from 31 to 61 and suspect clinical group with score no less than 62.After controlling for potential confounders,multivariate logistic regression analysis was performed to evaluate the main effects and the interaction between passive smoking and folic acid supplement during pregnancy on children ASD behaviors.Results Maternal passive smoking during pregnancy was significantly associated with children ASD behaviors (sub-clinical group:OR=1.48;suspect clinical group:OR=2.85),and maternal folic acid supplement during pregnancy was not related to children ASD behaviors (sub-clinical group:OR=1.04;suspect clinical group:OR=0.75).Stratified analysis showed that folic acid supplement during pregnancy was negatively associated with children ASD behaviors (suspect clinical group:OR=0.30) among children without mothers' passive smoking during pregnancy,and that mothers' passive smoking during pregnancy was positively associated with children ASD behaviors (sub-clinical group:OR=1.52;suspect clinical group:OR=4.45) among the children whose mothers had folic acid supplement during pregnancy.Furthermore,an interaction effect on children ASD behaviors was found between passive smoking and folic acid supplement during pregnancy (suspect clinical group:OR=5.30).Conclusion Passive smoking and folic acid supplement during pregnancy were related to children ASD behaviors and had an interaction on children ASD behaviors.