OBJECTIVE To reveal the role of the basal forebrain(BF)GABAergic neurons in the regulation of isoflurane anesthesia and to elucidate the underlying neural pathways.METHODS The activity of BF GABAer-gic neurons was monitored during isoflurane anesthesia using a genetically encoded calcium indicator in Vgat-Cre mice of both sexes.The activity of BF GABAer-gic neurons was manipulated by chemogenetic and opto-genetic approaches.Sensitivity,induction time and emer-gence time of isoflurane anesthesia were estimated by righting reflex.The electroencephalogram(EEG)power and burst-suppression were monitored by EEG recording.The effects of activation of GABAergic BF-thalamic reticu-lar nucleus(TRN)pathway on isoflurane anesthesia were investigated with optogenetics.RESULTS The activity of BF GABAergic neurons was generally inhibited during isoflurane anesthesia,obviously decreased during the induction of anesthesia and gradually restored during the emergence from anesthesia.Activation of BF GABAergic neurons with chemogenetics and optogenetics promoted behavioral emergence from isoflurane anesthesia,with decreased sensitivity to isoflurane,delayed induction and accelerated emergence from isoflurane anesthesia.Optogenetic activation of BF GABAergic neurons prom-oted cortical activity during isoflurane anesthesia,with decreased EEG delta power and burst suppression ratio during 0.8%and 1.4%isoflurane anesthesia,respectively.Similar to the effects of activating BF GABAergic cell bod-ies,photostimulation of BF GABAergic terminals in the TRN also strongly promoted cortical activation and behav-ioral emergence from isoflurane anesthesia.CONCLU-SION The GABAergic neurons in the BF is a key neural substrate for general anesthesia regulation that facilitates behavioral and cortical emergence from general anesthe-sia via the BF-TRN pathway.

Objective To investigate the changes of nutrients in colostrum， transitional milk， mature milk and late milk after storage at indoor temperature for 3 h， at 4 ℃ for 24 h， at -18 ℃ for 30 d， and at -18 ℃ for 90 d， so as to select the most suitable storage method of milk. Methods Fifteen pregnant women registered in the Shanghai Hongkou Liangcheng Village Street Community Health Service Center， who were expected to give birth from January to June in 2019， were selected. The breast milk of each woman was followed from delivery to 10 months after breast-feeding. Colostrum， transitional milk， mature milk and late milk were sampled， and each sample was divided into 5 parts. Changes in protein， fat， lactose， minerals， carbohydrates， vitamins and bacterial colony number of breast milk were detected according to 0 h（16-18 ℃）， 3 h （16-18 ℃）， 24 h （4 ℃） to 37 ℃， 30 d （-18 ℃） to 37 ℃ after thawing at 40 ℃ and 90 d （-18 ℃） to 37 ℃ after thawing at 40 ℃. Results The results showed that the nutritional components of milk in different stages decreased with time. However， there was no significant difference in the decline of nutritional components in different stages of milk after the same duration of time （ P >0.05）. Conclusion The milk at each stage can be stored， and the lactating mother can store the excess milk at any stage as she wishes.

Objective:To investigate the changes of autonomic nervous active substances in myocardium of rats with acute high-level spinal cord injury.Methods:Twenty-four clean-level healthy adult male SD rats weighting 250-300 g for 8-10 weeks old were divided into control group ( n=6) and spinal cord injury group ( n=18) according to the random number table. The spinal cord injury group was subdivided at 4, 12 and 24 hours, with 6 rats at each time point. The high-level spinal cord injury model was established by the modified Allen′s weight-drop method, and the spinal cord was only exposed in control group. The postoperative performance and BBB score for limb movement were observed in each group. The myocardium of each group was resected and used to observe ultrastructure of myocardial cells under transmission electron microscope and detect protein and mRNA levels of tyrosine hydroxylase (TH), noradrenaline transporter (NET), acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) by Western blot and RT-PCR analysis. Results:Rats of control group showed normal limb motion after operation without significant change from the preoperation level, and mean BBB score was 21 points. Rats of spinal cord injury group showed significantly reduced activities and feeding, with flaccid paralysis of both lower limbs as well as no spontaneous excretion, and showed BBB score of 0 point at 4 hours and 12 hours after injury, which was increased slightly at 24 hours after injury, with the highest score for 1 point. The ultrastructure of myocardial cells showed no obvious abnormalities in control group, while different degrees of changes in spinal cord injury group. Compared with control group, Western blot analysis showed that protein levels of TH and NET were decreased, while AChE and ChAT were increased in spinal cord injury group ( P<0.05 or 0.01). Compared with control group, RT-PCR analysis showed that mRNA levels of TH and NET were decreased, while AChE and ChAT were increased in spinal cord injury group ( P<0.05 or 0.01). mRNA levels of TH and NET in spinal cord injury group at 24 hours after injury were significantly different from those at 4 hours and 12 hours after injury (all P<0.05). mRNA levels of ChAT in spinal cord injury group were statistically significant at 12 hours and 24 hours after injury from those at 4 hours after injury, with significant difference at 12 hours and 24 hours after injury (all P<0.05). Conclusion:Sympathetic nerve active substances TH and NET are down-regulated but vagal nerve active substances AChE and ChAT up-regulated in myocardium of rats with acute high-level spinal cord injury, which may be related to the relative excitation of the parasympathetic nerve blocking the sympathetic innervation of the higher center to the heart following high-level spinal cord injury.

Objective To evaluate the effect of dexmedetomidine on phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3 beta (GSK-3β) signaling pathway during apoptosis in cardiomyocytes of rats with severe scald.Methods Twenty-four healthy adult male SpragueDawley rats,weighing 220-280 g,were divided into 3 groups (n=8 each) using a random number table method:control group (group C),severe scald group (group S) and dexmedetomidine group (group D).Thirty percent of the total body surface area was shaved on the back and then exposed to 94 ℃ water (with 37 ℃ warm water in group C) for 12 s to establish the model of third degree scald in pentobarbital sodium-anesthetized rats.Dexmedetomidine 30 μg/kg (2 μg/ml) was intraperitoneally injected immediately after scald in group D.Rats received anti-shock treatment by intraperitoneal injection of isotonic saline according to Parkland formula,and group C received no injection.Rats were anesthetized using the method previously mentioned at 12 h after treatment,and myocardial specimens of the left ventricle were rapidly excised and stored at-80 ℃ for determination of cell apoptosis (by TUNEL) and expression of P13K,phosphorylated Akt (p-Akt) and phosphorylated GSK-3β (p-GSK-3β) (by Western blot).Apoptosis index (AI) was calculated.Results Compared with group C,AI was significantly increased,and the expression of P13K,p-Akt and p-GSK-3β was up-regulated in S and D groups (P＜0.05).Compared with group S,AI was significantly decreased,and the expression of P13K,p-Akt and p-GSK-3β was up-regulated in group D (P＜0.05).Conclusion Dexmedetomidine inhibits apoptosis in cardiomyocytes through activating PI3K/Akt/GSK-3β signaling pathway in the rats with severe scald.

Objective To evaluate the effect of low-flow sevoflurane anesthesia on the early postoperative renal function in patients.Methods Sixty patients of both sexes,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,aged 18-64 yr,scheduled for elective non-urological surgery with general anesthesia,with an expected surgical duration＞4 h,were divided into 2 groups (n =30 each) using a random number table method:middle-flow anesthesia group (group Ⅰ) and low-flow anesthesia group (group Ⅱ).Anesthesia was induced with Ⅳ midazolam,sufentanil,propofol and cisatracurium besylate.Mechanical ventilation was performed after tracheal intubation.Pure oxygen served as carrier,the fresh gas flow of oxygen was set at 4-5 L/min,sevoflurane was inhaled for 10-15 min,and then fresh gas flow was decreased to 2 L/min (group Ⅰ) and 0.5 L/min (group Ⅱ).End-tidal pressure of carbon dioxide was maintained at 35-45 mmHg.The end-tidal concentration of sevoflurane was set at 2.0％-2.4％,remifentanil and cisatracurium besylate were infused intravenously,and sufentanill or propofol was injected intermittently to maintain anesthesia.Bispectral index value was maintained at 40-60 during operation.Before anesthesia induction (T0),at 1,2,3 and 4 h after anesthesia induction (T1-4),immediately after operation (T5) and at 24 h after operation (T6),peripheral venous blood samples were collected for determination of serum fluoride ion concentrations.Peripheral venous blood samples and urine specimens were collected at T0,T5,T6,48 h after operation (T7) and 72 h after operation (T8) for determination of creatinine (Cr),blood urea nitrogen (BUN) and cystatin C (Cys C) and serum and urine β2-microglobulin (β2-MG) concentrations.Results Compared with the baseline at T0,serum fluoride ion concentrations were significantly increased at T1-6 in two groups,the serum Cys C concentration was increased at T5,and serum and urine β2-MG concentrations were increased at T5 and T6 in group Ⅰ,serum Cr and BUN concentrations and serum and urine β2-MG concentrations were increased at T5 and T6,and the serum Cys C concentration was increased at T5-T7 in group Ⅱ (P＜0.05).Compared with group Ⅰ,serum fluoride concentrations were significantly increased at T1-6,serum Cr and BUN concentrations and serum and urine β2-MG concentrations were increased at T5,and serum Cys C concentrations at T5-T7 and urine β2-MG concentrations at T5 and T6 were increased in group Ⅱ (P＜0.05).Conclusion Low-flow sevoflurane anesthesia produces no marked effect on early postoperative renal function in patients.

Objective To investigate the effect of dexmedetomidine on protein kinase RNA-like endoplasmic reticulum kinase (PERK) signaling pathway in cardiomyocytes of the rats with severe scald.Methods Twenty-four healthy adult male Sprague-Dawley rats,weighing 220-280 g,were randomly divided into 3 groups (n =8 each) using a random number table:control group (group C),severe scald group (group S),and scald + dexmedetomidine group (group D).Thirty percent of the total body surface area was shaved on the back and then exposed to 94 ℃ water for 12 s to establish the model of 3rd degree scald.Dexmedetomidine 30 μg/kg (2 μg/ml) was intraperitoneally injected immediately after scald in group D.Myocardial specimens were obtained at 12 h after scald for examination of the pathological changes and for determination of cell apoptosis and expression of C/EBP-homologous protein (CHOP),PERK,and phosphorylated PERK (p-PERK) by Western blot.The apoptosis index and p-PERK/PERK ratio were calculated.Results Compared with group C,the apoptosis index was significantly increased,the expression of CHOP,PERK and p-PERK was significantly up-regulated,and the p-PERK/PERK ratio was significantly increased in S and D groups (P＜0.05).Compared with group S,the apoptosis index was significantly decreased,the expression of CHOP,PERK and p-PERK was significantly down-regulated,and the p-PERK/PERK ratio was significantly decreased (P＜0.05),and the pathological changes of myocardium were significantly attenuated in group D.Conclusion The mechanism by which dexmedetomidine inhibits apoptosis in cardiomyocytes is related to inhibition of PERK signaling pathway in the rats with severe scald.

Objective To evaluate the changes in the expression of spinal aquaporin-4 (AQP4) during remifentanil-induced hyperalgesia in a mouse model of incisional pain.Methods Seventy-two pathogen-free healthy adult male CD1 mice,weighing 25-30 g,were divided into 4 groups (n=18 each) using a random number table:control group (group C),incisional pain (group I),remifentanil group (group R) and remifentanil plus incisional pain group (group R+I).Normal saline was infused subcutaneously in group C.An incision was made in the left hind paw in group I.Remifentanil 80 μg/kg was subcutaneously infused for 30 min at a rate of 0.8 ml/h in group R.Remifentanil was infused subcutaneously before establishment of the model in group R+I.The thermal paw withdrawal latency (TWL) and mechanical paw withdrawal threshold (MWT) were measured at 1 day before establishment of the model (T0) and 6 h and 1,2 and 7 days after establishment of the model (T1-4).After measurement of the pain threshold at T3,12 animals were sacrificed randomly,and the lumbar segment of the spinal cord was removed for determination of the distribution and expression of AQP4 by Western blot.Results Compared with group C,the TWL was significantly shortened at T1-3,and the MWT was decreased at T2-4 in R and R + I groups,and the expression of AQP4 was significantly up-regulated at T3 in I,R and R+I groups (P＜0.05).Compared with group I,the TWL was significantly shortened at T2,3,and the MWT was decreased at T2.4 in group R,and the TWL was significantly shortened at T1-3,the MWT was decreased at T2.4,and the expression of AQP4 was up-regulated at T3 in group R+I (P＜0.05).Conclusion The mechanism by which remifentanil induces hyperalgesia is related to up-regulation of AQP4 expression in the spinal cord in a mouse model of incisional pain.

Objective To evaluate the effect of acute hypervolemic hemodilution (AHH) on myocardial damage in severely burned rabbits.Methods Eighteen healthy adult rabbits,weighing 2.0-2.5 kg,were randomly divided into 3 groups (n =6 each) using a random number table:control group (group C),burn group (B group) and AHH group.Rabbits were subjected to 3rd degree burn covering 40％ of the total body surface area.After the model was established,6％ hydroxyethyl starch 130/0.4 was infused intravenously,and the target Hct was 25％ in AHH group.Before AHH (To) and at 2,4 and 8 h after AHH (T1-3),left ventricular systolic pressure (LVSP),left ventricular end-diastolic pressure (LVEDP),+dp/dtmax and-dp/dtmax were recorded,and blood samples from femoral veins were taken to determine the concentration of serum cardiac troponin I (cTnI) by ELISA.The rabbits were sacrificed at T3,and myocardial specimens were removed for microscopic examination of pathological changes with light microscope.Results Compared with group C,the serum cTnI concentration and LVEDP were significantly increased,LVSP and +dp/dtmaxwere decreased at T1-3 in B and AHH groups,and-dp/dtmax at T1-3 in group B and-dp/dtmax at T3 in group AHH were decreased.Compared with group B,LVSP,+dp/dtmax and-dp/dtm,x were significantly increased at T1-3,and no significant change was found in serum cTnI concentration and LVEDP in group AHH.There was no significant difference in the pathological changes between group B and group AHH.Conclusion AHH can not aggravate the early myocardial damage in severely burned rabbits.

Objective To explore the factors that affect the teaching effect of medical statistics study for clinical postgraduates and to provide a reference for further improving teaching Quality. Methods Four hundred and eighty-nine students who had attended Medical statistics in 2013 Fall semester were surveyed by the self-designed questionnaire. The Logistic regression model was used to analyze the factors affecting the learning effect. Results A total of 489 questionnaires were distributed and 488 valid questionnaires were returned (the return rate was 99.80%). 71.11% (347/488) were entirely in favor of giving medical statistics course while 23.98% were relatively supportive. Statistics recognition, learning motivation, finishing homework and the satisfaction of learning were the factors that affect the grades. The OR values are 1.547, 1.723, 1.374, 1.433 for the above four factors respectively. The difference was statistically significant (P<0.05). Conclusion In medical statistics teaching, it can improve students' performance by introducing case study, simplifying the mathematical formula, combi-ning the theory and computer statistical software practice, and improving teaching methods, which helps improve the quality of teaching.

Objective To evaluate the effects of remifentanil post-conditioning on aquaporin-1 (AQP-1) expression during myocardial ischemia-reperfusion (I/R) injury in rats.Methods Twenty-four male.SpragueDawley rats,weighing 250-300 g,were randomly divided into 3 groups (n =8 each) using a random number table:sham operation group (group S),group I/R,and remifentanil post-conditioning group (group RP).Myocardial I/R was induced by 45 min occlusion of left anterior descending branch of coronary artery followed by 24 h reperfusion.Remifentanil 10 μg· kg-1· min-1 was infused over 10 min starting from 10 min before reperfusion in group RP,while the equal volume of normal saline was given instead in S and I/R groups.At the end of reperfusion,all the rats were sacrificed and their myocardial specimens from left ventricles were obtained for microscopic examination of thepathological changes and for determination of AQP-1 mRNA (using real-time fluorescent quantitative PC R) and AQP-1 protein (by Western blot) expression in the ischemic area and myocardial water content.Results Compared with S group,myocardial water content was significantly increased in the other two groups,AQP-1 mRNA and protein expression was up-regulated in group I/R,and no significant change was found in AQP-1 mRNA and protein expression in RP group.Compared with I/R group,myocardial water content was significantly reduced,and AQP-1 mRNA and protein expression was down-regulated in RP group.Conclusion Remifentanil post-conditioning reduces myocardial I/R injury possibly through down-regulating AQP-1 expression in myocardial tissues of rats.