Objective To study the effects of short-term and long-term exposure to extremely low frequency electromagnetic field(ELFEMF)on Morris learning and memory among rats. Methods Both younger(2-3 months old)and adult(18 months old)male SD rats were exposed to 50 Hz uniform ELFEMF with continuously adjusted intensities(0.1,1.2,1.6 mT) developed by Helmholtz coil pair for 10 days to 8 months. The levels of escape latency and the crossing annulus coefficients reflecting the behavioral changes in place navigation ability and spatial probe ability were examined by Morris water maze after exposure to ELFEMF among rats. Results The escape latency was shortened and the crossing annulus coefficients were increased compared with those of control group when the younger rats were exposed to 0.1,1.2 and 1.6 mT ELFEMF for 10 days respectively,and only revealed significant differences in 1.2 and 1.6 mT ELFEMF exposure groups compared with those of control group. In the younger rats of 1.6 mT ELFEMF exposure group with 10-day exposure ,their escape latencies were prolonged and the crossing annulus coefficients were decreased gradually and showed no significant differences compared with those of control group after the 30-day blank exposure period without ELFEMF.The younger rats of 1.2 mT ELFEMF exposure group showed significantly longer escape latency and lower crossing annulus coefficient compared those of control group after continuous 90-day exposure to 1.2 mT ELFEMF. The escape latency of adult rats in 0.1 mT ELFEMF exposure group showed no significant difference after 10-day exposure,was prolonged after 4-month exposure,and was significantly prolonged further more after 8-month exposure. Conclusion The learning and memory ability could be promoted by short-term ELFEMF exposure and impaired by long-term ELFEMF exposure for the young rats,and could be obviously inhibited by long-term ELFEMF exposure for the adult rats.

Objective To investigate the effect of 50Hz magnetic field on the monoamine neurotransmitters contents in the hippocampus of rats. Methods 32 male SD rats were divided into 4 groups, exposed to 50 Hz magnetic field at the density of 0, 0.1, 1.2, and 1.6 mT, 2 h a day for a certain time. The contents of NE, E, DA and 5-HT were measured by HPLC. Results The contents of NE, DA and 5-HT in hippocampus were increased when the young rats were exposed to 1.2 and 1.6 mT for 10 days, the changes of monoamine neurotransmitters in 0.1 mT exposed group was not significant. The increase in monoamine neurotransmitters was disappeared when the 1.6 mT exposed group stop being exposed to the magnetic field for 30 days, while the monoamine neurotransmitters contents were decreased when the young rats were continuously exposed to 1.2 mT for 90 days. The contents of NE, DA and 5-HT, except E, in the old rats were decreased significantly when exposed to 0.1 mT intensity for 8 months. Conclusion Magnetic field exposure may affect the monoamine neurotransmitters content in the hippocampus, which may be responsible for the changes of learning and memory of rats induced by 50 Hz magnetic field exposure.

AIM To study the adaptive cytoprotection of H 2O 2 preconditioning against oxidative stress damage in PC12 cell and the relationships between brain derived neurotrophic factor (BDNF) and the adaptive cytoprotection of H 2O 2 preconditioning. METHODS The viability of PC12 cells was evaluated by MTT assay. Apoptosis was detected by PI stain flow cytometer. Expression of BDNF was analyzed by immuo flow cytometer. RESULTS After H 2O 2 preconditioning, the survival of PC12 cells exposure to H 2O 2 (20～60 ?mol?L -1 ) was increased and the apoptosis of PC12 cells induced by H 2O 2 (20 or 30 ?mol?L -1 ) was inhibited and the expression of BDNF in PC12 cells was enhanced. CONCLUSION H 2O 2 preconditioning is protective against the damage of PC12 cells induced by H 2O 2 and its mechanisms may involve up modulation of the expression of BDNF.

AIM To study the expression of brain-derived neurotrophic factor (BDNF) in lymphocytes modified by BDNF gene and its effect on the proliferation and the H 2O 2-induced apoptosis of PC12 cells for the transfer of ex vivo therapeutic gene into central nervous system (CNS) tissue with atraumatic means. METHODS Recombined BDNF cDNA plasmid was transfected by LipofectAMINE into the packing cell line PA317 and G418-resistant clones with highest titer was selected. Rat lymphocytes were infected repeatedly with virus supernatant. The expression of BDNF in rat lymphocytes was assayed by FCM and immunohistochemistry. The proliferation of PC12 cells was evaluated by MTT assay. H 2O 2-induced apoptosis of PC12 cells was determined by PI stain flow cytometry. RESULTS BDNF expressed in rat lymphocytes genetically modified and the concentration of BDNF in the conditioned medium of engineered lymphocytes had a linear correlation with the proliferation of the PC12 cells. The supernatant of lymphocytes modified by BDNF gene decreased the apoptosis of PC12 cells induced by H 2O 2. CONCLUSION Rat lymphocytes genetically modified can express and secret active BDNF in vitro.

To study the changes in skeletal muscle structure and insulin resistance of low birth weight rats.The low birth weight filial rat model was established by feeding low protein diet to the pregnant rat during gestation.At 7 d,21 d,and 2 months,blood glucose and serum insulin were measured,and the structure of skeletal muscle was observed.From 7 d to 2 months,the muscle fibers of low birth weight rat were atrophic and arranged in disorder.The ultrastructure of skeletal muscle was also abnormal distinctly at 2 months.No differences of blood glucose and rerum insulin were found between the two groups.

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 observe the influence of L-Arg supplementation during early postnatal life on renal function of rats with intrauterine growth retardation(IUGR).Mehod Afer establishment of IUGR model with 10% protein diet,rats were divided randomly into 2 groups: IUGR group and L-Arg treated group(LT group).Normal control group(NC group) rats were fed with 20% protein diet.The level of NO,Cr in serum were measured from 1 w to 3 months and UCr,24 h-proteinuria were measured from 3 w to 3 months.Results(1)The levels of serum NO reduced significantly in group IUGR at every stage,not significantly different between group LT and NC,but more in group LT than in group IUGR.(2)The levels of 24h-proteinuria had no significant difference among three groups at 3 w and 2 month,but was significantly higher in group IUGR than group LT and group NC.(3)The Cr levels had no significant difference at every stage among three groups.The UCr level was decreased in group IUGR than group NC at 2 month and than group NC and LT at 3 month.(4)The level of CCr in group IUGR was decreased significantly at 3 w,2 month and 3 month than group LT and group NC.Conclusion L-Arg can increase serum NO and CCr levels and decrease the level of 24h-proteinuria in rats with IUGR.It is one of the important reasons to increase 24h-proteinuria and reduce CCr level for low NO value.

Objective To evaluate left ventricular myocardial function altemation by three-dimensional speckle tracking imaging (3D-STI) after surgical aortic valve replacement (AVR) in severe aortic stenosis (AS) patients with preserved left ventricular ejection fraction (LVEF),and discuss its clinical value.Methods Forty patients with severe aortic stenosis who were hospitalized or outpatient in Nanjing First Hospital Affiliated to Nanjing Medical University during the period of October 2014 to October 2016 (AS group),and forty healthy volunteers (normal control group) were enrolled in this study.Normal control group underwent conventional echocardiography and 3D-STI measurement,while the AS group underwent conventional echocardiography and 3D-STI measurement at preoperative,1 week postoperative and 3 months postoperative,then we obtained left ventricular end-diastolic diameter (LVEDD),left ventricular end-systolic diameter (LVESD),interventricular septum thickness diameter (IVSd),left ventricular posterior wall thickness diameter (LVPWd),left ventricular ejection fraction (LVEF),global longitudinal strain (GLS),global circumferential strain (GCS),global radial strain (GRS),global area strain (GAS) strain and 3D-strain.The independent sample t test was used to compare the difference of conventional ultrasound parameters and 3D-STI parameters between AS preoperative patients and healthy controls,AS patients at 3 months postoperative and healthy controls.The single factor analysis of variance was used to compare the difference of conventional ultrasound parameters and 3D-STI parameters in severe patients at preoperative,1 week postoperative and 3 months postoperative.LSD-t test was used to compare in different AS groups.Results Compared with normal control group,IVSD,LVPWD and GCS of severe AS patients increased significantly (t=13.824,11.298 and-6.584,all P ＜ 0.001),GLS,GRS and 3D-Strain decreased significantly (t=10.221,-6.237 and-5.674,all P ＜ 0.001),LVEDD,LVESDand GAS had no significant difference.Compared with preoperative AS patients,LVEF,GLS,GAS and GCS decreased significantly (t=-2.205,-2.093,-2.034 and-3.152,all P ＜ 0.05 or 0.01) at 1 week postoperative,LVEDD,LVESD,IVSD,LVPWD,GRS and 3D-strain had no significant difference at 1 week postoperative;GLS,GRS and 3D-strain increased significantly (t=5.446,-4.923 and-4.388,all P ＜ 0.05 or 0.01) at 3 months postoperative,GCS,IVSD and LVPWD decreased significantly (t=-3.988,4.794 and 4.211,all P ＜ 0.05 or 0.01) at 3 months postoperative,LVEDD,LVESD,LVEF and GAS had no significant difference at 3 months postoperative.Compared with AS patients at 1 week postoperative,LVEF,GLS,GRS,GAS and 3D-strain increased significantly (t=-2.631,7.383,-4.719,2.923 and-4.154,all P ＜ 0.05 or 0.01) at 3 months postoperative,GCS,IVSD and LVPWD decreased significantly (t=-2.109,4.747 and 4.323,all P ＜ 0.05 or0.01) at 3 months postoperative.But in AS patients at 3 months postoperative,IVSD,LVPWD,GLS and GCS were still higher than those of normal control group (t=9.809,7.066,4.752 and-2.553,all P ＜ 0.001 or ＜ 0.05),LVEDD,LVESD,LVEF,GRS,GAS and 3D-strain had no significant difference.Conclusion The alternation of left ventricular myocardial function have a certain characteristic before and after aortic valve replacement in severe aortic stenosis patients with preserved LVEF,and 3D-STI can evaluate it more accurately.

Objective:To analyze the cost of diagnosis-intervention packet(DIP) in a certain hospital in 2021 based on hospital intelligent agents, so as to provide feasible ideas for refined management of DIP costs.Methods:On the basis of the construction of the hospital intelligent agent platform and the results of project cost accounting in the early stage, a total of 60 187 cases and 4 860 DIP diseases in the hospital in 2021 were selected as the research objects. The project superposition method was applied to calculate the unit cost of all DIP diseases in the hospital. Based on the results of DIP cost accounting, the ideas and methods of fine management of DIP costs were explored from the perspectives of DIP disease classification, management of all hospital diseases and medical insurance diseases, vertical and horizontal comparative analysis of DIP costs, and management of medical insurance cases and non medical insurance cases under the same DIP disease category.Results:Twenty-two advantageous DIP disease types, 67 key disease types, 1 590 potential disease types, and 3 181 disadvantageous disease types were identified. Introducing medical income as an intermediate indicator facilitated the classification of DIP disease types under medical insurance, 1 072 advantageous disease types, 917 key disease types, 458 potential disease types, and 815 disadvantageous disease types in medical insurance were identified. Through refined accounting, it was found that the average cost of non medical insurance cases under the same DIP disease category was generally higher than that of medical insurance cases, and there were differences in DIP costs at different levels during different time periods.Conclusions:By determining and analyzing the advantages and disadvantages of disease types in the entire hospital, common problems of disease types under the same category can be identified, and targeted control measures can be proposed. By analyzing the two dimensions of medical insurance surplus and medical surplus, the advantages and disadvantages of medical insurance diseases can be quickly determined, providing a lever for the control of medical insurance diseases. The horizontal and vertical comparative analysis of DIP costs, as well as the analysis of medical insurance cases and non medical insurance cases under the same DIP disease category, can provide feasible methods for hospitals to manage DIP costs at multiple levels and dimensions.

Objective:To study the clinical characteristics of different types of neonatal sepsis.Methods:From January 2012 to December 2019, neonates with confirmed sepsis from 5 neonatal centers of central-south China were reviewed. The neonates were assigned into early-onset sepsis (EOS) and late-onset sepsis (LOS) group, and the latter was further subgrouped into hospital-acquired LOS (hLOS) group and community-acquired LOS (cLOS) group. The etiological and clinical characteristics were analyzed. SPSS 26.0 was used for statistical analysis.Results:A total of 580 neonates were enrolled, including 286 (49.3%) in the EOS group and 294 (50.7%) in the LOS group. In LOS group, 147 were in hLOS group and 147 were in cLOS group. The gestational age and birth weight of hLOS group were significantly lower than the other two groups [(32.7±3.6) weeks vs. (37.1±3.7) weeks and (37.7±3.0) weeks, (1 810±717) g vs. (2 837±865) g and (3 024±710) g] ( P<0.05). The common pathogens in EOS and cLOS groups were coagulase-negative staphylococci and Escherichia coli, while Klebsiella pneumoniae was common in hLOS group. Carbapenems usage in the hLOS group was significantly higher than the other two groups [62.6% vs. 28.7% and 16.2%] ( P<0.05). Antibiotics duration in the hLOS group was longer than the other two groups [19 (14, 27) d vs. 15 (12, 20) d and 14 (12, 19) d] ( P<0.05). Conclusions:The clinical characteristics of neonatal sepsis vary among different types of infections, and it is necessary to establish appropriate prevention, control, diagnosis and treatment protocols.