Objective To investigate the neural basis of glucagon-like peptide-1(GLP-1)in regulating glucose homeostasis and elucidate the molecular mechanisms.Methods Male Glp1r-IRES-Cre,Glp1r-KO,and wild-type mice were used in this study.Fiber photometry was employed to record Ca2+signals of neurons in ventromedial hypothalamus(VMH)and patch-clamp was used to analyze electrophysiological properties of GLP-1 receptor-positive(GLP-1RVMH)neurons.Viral stereotaxic injections,chemogenetics,plasma hormone assays,and routine glucose metabolism assessments were combined to determine the regulatory role of GLP-1RVMH neurons in glucose homeostasis.Tissue and cell mitochondrial respiratory function assays,transmission electron microscopy,and conventional molecular biology methods were used to explore the mechanism by which GLP-1R agonists regulate glucose homeostasis.Results When the glucose concentration decreased from 5.0 mmol/L to 0.5 mmol/L,the action potential frequency of GLP-1RVMH neuron decreased significantly[(4.51±0.80)Hz vs.(1.43±0.51)Hz,P<0.01].Activation of GLP-1RVMH neuron significantly enhanced insulin secretion[(7.60±0.56)μU/mL vs.(11.34±0.93)μU/mL,P<0.01],while inhibition of these neuronal activities impaired the hypoglycemic efficiency of GLP-1 agonists[(32.03%±0.91%)vs.(25.77%±1.09%),P<0.001)].Mechanistically,GLP-1 regulated glucose homeostasis through Drp1 phosphorylation-mediated mitochondrial fission and improved mitochondrial energy metabolism.Conclusion GLP-1RVMH neurons are a class of glucose-excited neurons,and which activated directly promotes secretion of insulin.The hypoglycemic effect of GLP-1R agonists depend on the neuronal activity of GLP-1RVMH.

Objective To investigate the neural basis of glucagon-like peptide-1(GLP-1)in regulating glucose homeostasis and elucidate the molecular mechanisms.Methods Male Glp1r-IRES-Cre,Glp1r-KO,and wild-type mice were used in this study.Fiber photometry was employed to record Ca2+signals of neurons in ventromedial hypothalamus(VMH)and patch-clamp was used to analyze electrophysiological properties of GLP-1 receptor-positive(GLP-1RVMH)neurons.Viral stereotaxic injections,chemogenetics,plasma hormone assays,and routine glucose metabolism assessments were combined to determine the regulatory role of GLP-1RVMH neurons in glucose homeostasis.Tissue and cell mitochondrial respiratory function assays,transmission electron microscopy,and conventional molecular biology methods were used to explore the mechanism by which GLP-1R agonists regulate glucose homeostasis.Results When the glucose concentration decreased from 5.0 mmol/L to 0.5 mmol/L,the action potential frequency of GLP-1RVMH neuron decreased significantly[(4.51±0.80)Hz vs.(1.43±0.51)Hz,P<0.01].Activation of GLP-1RVMH neuron significantly enhanced insulin secretion[(7.60±0.56)μU/mL vs.(11.34±0.93)μU/mL,P<0.01],while inhibition of these neuronal activities impaired the hypoglycemic efficiency of GLP-1 agonists[(32.03%±0.91%)vs.(25.77%±1.09%),P<0.001)].Mechanistically,GLP-1 regulated glucose homeostasis through Drp1 phosphorylation-mediated mitochondrial fission and improved mitochondrial energy metabolism.Conclusion GLP-1RVMH neurons are a class of glucose-excited neurons,and which activated directly promotes secretion of insulin.The hypoglycemic effect of GLP-1R agonists depend on the neuronal activity of GLP-1RVMH.

OBJECTIVE To understand the disinfection,use and management of ventilator for the sake of regulation.METHODS By interviewing and on-site survey,we understanded the method and the process of disinfection and found out the using cycle of the ventilator system and the conditions of its management.RESULTS Among 44 ventilators 7 models were found:the management of 18 ventilators was irregular;the other 26 ventilators were disinfected by 2 kind and 4 types disinfect methods.their using cycles were unsure,their processes of disinfection were irregular.The responsibilities for the disinfection were unclear,lacking of monitoring the effect of disinfection and their management was irregular.CONCLUSIONS The disinfection of ventilator using and management must be regulated.

Objective To investigate the contamination of Cd,Pb,Cu and Cr in the sediment of Guangzhou reach in Pearl River.Methods The sediments were collected in Yagang spot in April,2006.The content of heavy metals were determined,the heavy metals in the sediment were extracted with Tessier five stage sequential extraction procedure,and AAS was applied to determine the concentration of heavy metals in the sediment and extracts.Results The level of Cd,Pb,Cu,Cr were 2.29 mg/kg,217.97 mg/kg,320.60 mg/kg and 124.44 mg/kg respectively in the sediment in Yagang spot.They were higher than the background values of soil of Guangdong,and different heavy metals had different values of five forms.Cd existed as exchanged form mainly,and Cr,Pb existed as stable form mainly,so,Cd was easy to be resolved into water,Cr,Pb were relatively stable in the sediment.Conclusion The ecological risk of the four heavy metals is assessed with Hakanson potential ecological harmful index,the ecological risk of Cd is high,Cr,Pb is lower,Cu is moderate.