Objective To observe the effects of low dose of veratrine on the discharges of rat hippocampus pyramidal neurons,and to elucidate its possible cytological mechanism.Methods The discharge features of hippocampus CA1 pyramidal neurons of 14-day-aged healthy Sprague-Dawley rats induced by low dose(0.3～0.8?mol/L)of veratrine were observed by slice patch-clamp technique.Presynap- tic stimulation was given to Schaffer collaterals.Presynaptic receptor inhibitors such as 6-cyano-7-nitroquinoxaline-2,3-dione(CNQX, 5?mol/L),DL-2-amino-5-phosphonopentanoic acid(AP-5,12.5?mol/L),bicuculline(Bic,10?mol/L)and tetrodotoxin(TTX,40～80nmol/L)were used to investigate the influence on veratrine-induced epilepsy andⅠ-Ⅴcurves were plotted under these conditions.Elec- trophysiological mechanism of veratrine-induced epilepsy was elucidated on the basis of these experiments,Results After a perfusion with low dose of veratrine,the pyramidal neurons were found to discharge relatively fixed-mode slow wave epileptoid bursts accompanied with hyperpolarization of membrane potential.These epileptoid bursts were not blocked by a mixture of CNQX,AP-5 and Bic,but by low dose of TTX.After a perfusion with veratrine,Ⅰ-Ⅴrelationship tended to be nonlinear and the depolarization rectification was enhanced,which were reversed by administration of low dose of TTX.The subthreshold TTX-sensitive persistent sodium current of CA1 pyramidal cells was enhanced by veratrine in a voltage-dependent manner.Conclusion Inducing slow wave epileptoid bursts,the low dose of veratrine can remarkably change the discharge features of CA1 pyramidal neurons.Such epileptoid activities were not influenced by the synaptic receptor inhibitors,and were obviously related to the persistent sodium current.

Objective To observe the effects of phenytoin and gabapentin in therapeutic dosage on low-dose veratridine-induced epileptiform discharge in rats' hippocampal CA1 neurons,and explore the involved mechanisms.Methods By means of whole-cell patch clamp technique,the epileptiform discharge model of rats' hippocampal CA1 neurons was constructed with extracellular perfusion of 0.5?mol/L veratridine,and the model should be regarded as successfully estabilshed if bursting discharge emerged within 30min perfusion.The effects of phenytoin(2.5,5,10 and 15?mol/L) and gabapentin(2.5,5 and 10?mol/L) on the epileptiform activity were observed under the voltage-clamp configuration,and the current changes for 1 hour in CA1 neurons was also observed.Results Nine-sixteen minutes after veratridine perfusion,the huge,rhythmic slow oscillation emerged,with 100～200Hz high-frequency discharge,in the hippocampal CA1 neurons,which was similar to the paroxysmal depolarization shifts(PDS),implying that the epileptiform activity was reproduced.Therapeutic dose of phenytoin blocked the veratridine-induced epileptiform activity.The bursting interval of the epileptiform activity was prolonged along with the increased phenytoin concentration,and the duration of bursting was not shortened.1h current decreased gradually in the generation of veratridine-induced epileptiform activity.Therapeutic dose of gabapentin did not block the epileptiform activity in this model.Conclusions In the epileptiform discharge model of rats' hippocampal CA1 neurons,phenytoin can block the epileptic activity in a dose-dependent manner,and the effect may be related to the inhibition of 1h currents.Gabapentin shows no influence on the epileptiform activity,and the possible mechanism may be its ineffectiveness to the persistent sodium currents,and vertridine-induced epileptiform activity does not enhance the 1h currents.

BACKGROUND: The event of paroxysmal deplorizing shift (PDS) is the cellular hallmark of brain neurons of epileptiform activities. Its development used to be considered to be related to abnormal synaptic interactions. Recertly, the intrinsic nature of PDS has received more attention.OBJECTIVE: To observe the characteristics of epileptiform activities of rat hippocampal CA1 pyramidal neurons induced by low-dosage veratridine and investigate its possible ion mechanism.DESIGN: An exploratory and observational trial.SETTING: Institute of Neuroscience, Fourth Military Medical University of Chinese PLA.MATERIALS: This study was conducted at the Institute of Neuroscience,Fourth Military Medical University of Chinese PLA, from October 2002 to October 2004. Forty healthy SD rats of 14 days old were selected. Drugs were provided from Tianjin Drug Company and Sigma Company.METHODS: Rats were anesthetized by intraperitoneal injection, and their brain was removed and cut into slices. Epileptiform activities were induced by 0.5 μ mol/L veratridine. Then 80 nmol/L tetrodotoxin was added into the perfused solution on 6 cerebral slices, and 5 μmol/L phenytoin was used on another 5 cerebral slices. The electrophysiological characteristics of the cells under the effect of different kinds of drugs were observed.MAIN OUTCOME MEASURE: Discharge pattern of cells and tetrodotoxin-sensitive sodium currents under voltage-clamp configuration through Ⅰ-Ⅴ reaction.RESULTS: After perfusion of 0.5 μmol/L veratridine, the rat pyramidal neurons in CA1 area displayed relatively fixed-mode of runs of PDS bursting,followed by the hyperpolarization of cell membrane. Such epileptiform activities were blocked either by 80 nmol/L tetrodotoxin or 5 μnol/L phenytoin. The tetrodotoxin-sensitive sodium currents in epileptic neurons and normal controls under voltage-clamp configuration on holding potential of -55 rmV, -60 rmV, -65 mV. This shows that persistent sodium currents could be improved by low-dosage veratridine in a voltage-dependent manner.CONCLUSION: Low-dosage veratridine may induce runs of PDS like epileptiform activities on rat CA1 pyramidal neurons. Such changes can be blocked by low-dosage tetrodotoxin or phenytoin. Its ion mechanism may be related to persistent sodium currents.

Platypnea orthodeoxia syndrome is associated with dyspnea and arterial oxygen desaturation accentuated by an upright posture. It can be secondary to an intracardiac shunt. We report a case of platypnea-orthodeoxia syndrome (POS) in a 58-year old male patient who had a pre-existing patent foramen ovale (PFO) and substantial pulmonary pathologies. He was successfully treated by percutaneous transcatheter closure of the PFO. Our case highlights the importance of recognition of this rare syndrome in patients who present with unexplained hy-poxia for whom transcatheter closure of the interatrial shunt can be safely carried out.

Objectives To understand the effects of different doses of vitamin D supplementation on serum calcium,phosphorus,alkaline phosphatase and 25-hydroxyvitamin D levels in very low birth weight infants (VLBWI) and to provide guidance for early prevention of metabolic bone disease in VLBWI.Methods A total of 90 VLBWI hospitalized in the Department of Neonatology,Huzhou Maternal and Child Healthcare Hospital between January 2014 and January 2016 were enrolled and randomly divided into two groups:highdose group and low dose group.High-dose group was given vitamin D 900 U/d orally and low-dose group was given 400 U/d since the eighth day after birth.Serum calcium,phosphorus and alkaline phosphatase levels were detected at 1,7,21 and 42 days of age and serum 25-hydroxyvitamin D levels were detected at 7,21and 42 days of age.Two-sample t-test,Chi-square test,one-way analysis of variance and LSD or Dunnett's T3 test were used for statistical analysis.Results No significant differences in serum calcium,phosphorus and alkaline phosphatase levels were found between the two groups at 1 and 7 days of age,nor were found in serum 25-hydroxyvitamin D level at 7 days of age (all P＞0.05).At 21 days of age,high dose group had higher serum calcium,phosphorus and 25-hydroxyvitamin D levels than low-dose group [(2.38 ± 0.09) vs (2.04 ± 0.15) mmol/L,t=2.421;(1.80±0.50) vs (1.71 ±0.60) mmol/L,t-0.637;(45.58± 18.43) vs (42.53± 16.33) nmol/L,t=0.421],but lower alkaline phosphatase level [(505.12± 185.61) vs (588.32± 168.72) U/L,t=5.314] (all P＜0.05).The same trends were found at 42 days of age.In high-dose group,serum calcium level increased at 7,21 and 42 days of age as compared with that at 1 day of age [(2.43±0.13),(2.38±0.09),(2.39±0.08) vs (2.06±0.57) mmol/L];serum phosphorus level at 7 days of age was lower than that at 1,21 and 42 days of age [(1.31 ±0.26) vs (1.89±0.39),(1.80±0.50),(1.98±0.30) mmol/L];serum alkaline phosphatase level at 7,21 and 42 days of age was higher than that at 1 day of age [(475.18± 133.73),(505.12± 185.61),(538.43 ± 168.16) vs (296.15 ± 99.41) U/L] and a significant increase was observed at 42 days of age as compared with that at 7 days of age;serum 25 hydroxyvitamin D level at 21 days of age was higher than that at 7 days of age,and that at 42 days of age was higher than that at 7 and 21 days of age [(73.55±23.65) vs (30.63± 12.66) and (45.58 ± 18.43) nmol/L];the differences were all statistically significant (LSD or Dunnett's T3 test,all P＜0.05).Conclusions Vitamin D supplementation from the eighth day after birth can improve calcium and phosphorus metabolism in VLBWI and the dose of 900 U/d is more effective than 400 U/d.

BACKGROUND:The effects and molecular mechanism of simvastatin on the proliferation and differentiation of osteoblasts remain unclear. Especial y, we do not know much about the effects of connexin 43.
OBJECTIVE:To evaluate the effects of simvastatin on the proliferation and differentiation of osteoblasts and the regulatory effect of simvastatin on the expression of osteogenic genes and connexin 43.
METHODS:Newborn Sprague-Dawley rats were chosen and the cranium digestion method was used to culture osteoblasts. The different concentrations of simvastatin (0.062 5, 0.125, 0.25, 0.5 and 1.0μmol/L) were used to deal with osteoblasts. The proliferative effect of simvastatin on osteoblasts was measured with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. The effect of simvastatin on osteoblast differentiation was measured with alkaline phosphatase activities. The mRNA and protein expression of osteogenic genes and connexin 43 were measured by real time quantitative RT-PCR and western blot assay.
RESULTS AND CONCLUSION:There were no significant differences in absorbance values of simvastatin groups at 3 days (P>0.05). However, at 4 and 5 days, absorbance values were lower in the simvastatin groups than those in the control group (P<0.05). Compared with the control group, alkaline phosphatase activities of osteoblasts were greater in the simvastatin groups (P<0.05). Moreover, the effects of 0.25μmol/L simvastatin on alkaline phosphatase activities of osteoblasts were most significant. Osteocalcin, alkaline phosphatase activities, type I col agen and connexin 43 mRNA and protein expressions were increased after treatment with 0.25μmol/L simvastatin (P<0.05). These results indicated that simvastatin may inhibit the proliferation and improve the differentiation of osteoblasts by upregulating the mRNA and protein expression of osteogenic genes and connexin 43. These data may provide the new intervention target for osteoporosis treated with statins.

Objective: To compare the efficacy and safety of Cardi-O-fix patent foramen ovale (PFO) occluder and Amplatzer PFO occluder for the treatment of patients with PFO. Methods: A total of 246 consecutive patients (105 males and 141 females) with PFO were prospectively enrolled from May 30, 2013 to March 30, 2015 in our hospital. PFO interventional closure was applied according to the anatomical structure of the disease and patients′ wishes.Cardi-O-fix PFO occluder was used in 180 cases (COF group), Amplatzer PFO occluder was used in the remaining 66 cases (Amp group). Post-procedure safety including recurrent stroke, transient ischemic attack, death, and complete closure rate, and efficacy including procedure related complications of different devices were compared during the 12 months follow-up. Results: (1) Rate of transient ischemic attack was similar between COF group and Amp group at 12 months after procedure(1.1%(2/180) vs. 1.5%(1/66), P=1.000). There was no recurrent stroke and death during the 12 months follow-up period.Complete closure rate was similar between COF group and Amp group at 12 months after the procedure(90.6%(163/180)vs. 86.4%(57/66), P=0.355). (2) Three cases(1.7%) of paroxysmal atrial fibrillation were observed in COF group during the 12 months follow-up period, 1 patient converted spontaneously to sinus rhythm and 2 patients received successful pharmacologic conversion and converted to sinus rhythm. One patient(1.5%)developed paroxysmal atrial fibrillation and was pharmacologically converted to sinus rhythm in the Amp group. There was no significant difference in rate of paroxysmal atrial fibrillation between the two groups(P=1.000). There was no complications such as occluder translocation, erosion, pericardial effusion and puncture site bleeding in the 2 groups during the 12 months follow-up. Conclusion Efficacy and safety are similar for PFO treatment with Cardi-O-fix PFO occluder or Amplatzer PFO occluder in this patient cohort.

Objective To investigate the clinical features and antimicrobial susceptibility of neonatal Listeria septicemia.Methods Eleven cases of neonatal Listeria septicemia that were treated in the Huzhou Maternity and Children Health Hospital from March 2013 to March 2017 were enrolled in this study.Clinical data including the results of bacterial culture,antimicrobial susceptibility test and antibiotic treatment were collected and retrospectively analyzed.Moreover,maternal history of Listeria monocytogenes (LM) infection before delivery was retrieved.Results All of the 11 mothers had fever before delivery and nine of them showed different grades of amniotic fluid contamination during delivery.Clinical symptoms of the 11 neonates included dyspnea (11 cases),fever (ten cases),apnea (nine cases),slow response and feeding difficulty (nine cases),convulsion (six cases),vomiting and abdominal distension (two cases),pulmonary hemorrhage (one case),progressive jaundice (one case) and systemic skin bleeding point (one case).All cases showed abnormal results of blood routine test and increased calcitonin and C-reactive protein.Ten cases received cercbrospinal fluid examination,seven of which were abnormal.Altogether 17 strains of LM were isolated from various specimens.These strains were all sensitive to piperacillin-tazobactam,ampicillin-sulbactam,meropenem,vancomycin,cotrimoxazole,ciprofloxacin and gentamycin,but resistant to oxacillin.Strains those were sensitive to penicillin,ampicillin,erythromycin and clindamycin accounted for 10/17,11/17,9/17 and 8/17,respectively.The 11 neonates were treated with piperacillin-tazobactam,meropenem or vancomycin.All of them improved (11/11)and ten were cured (10/11).All cases were followed up through phone calls at one week and one month after discharge.Two were lost to follow-up,while thc others were all in good condition.Conclusions Neonatal Listeria septicemia is usually a severe disease characterized by rapid progression and mainly presented with dyspnea and fever,besides there is a high possibility of purulent meningitis.Some LM strains are resistant to single-agent penicillin antibiotics.However,antibiotics such as piperacillin-tazobactam,meropenem and vancomycin are effective in the treatment of neonatal Listeria septicemia.

Objective:To investigate the effect of high flow nasal catheter ventilation (HFNC) in mechanical ventilation withdrawal of premature infants and its influence on blood gas analysis.Methods:The clinical data of 60 premature infants with mechanical ventilation from January 2017 to December 2018 in Huzhou Maternal and Child Health Hospital were analyzed retrospectively. After withdrawal, 30 premature infants treated with nasal continuous positive airway pressure (NCPAP) were as NCPAP group, and 30 premature infants treated with HFNC were as HFNC group. The ventilation time, total oxygen use time, complications, and arterial partial pressure of oxygen (PaO 2) and arterial partial pressure of carbon dioxide (PaCO 2) 12 and 24 h after withdrawal were compared between 2 groups. Results:There were no statistical differences in ventilation time and total oxygen use time between 2 groups ( P>0.05). The incidence of complications in HFNC group was significantly lower than that in NCPAP group: 13.33% (4/30) vs. 46.67% (14/30), and there was statistical difference ( P<0.05). The PaO 2 12 and 24 h after withdrawal in HFNC group was significantly higher than that in NCPAP group: (68.83 ± 2.76) mmHg (1 mmHg=0.133 kPa) vs. (64.79 ± 2.31) mmHg and (78.46 ± 3.32) mmHg vs. (74.72 ± 2.18) mmHg, the PaCO 2 was significantly lower than that in NCPAP group: (48.93 ± 2.51) mmHg vs. (52.31 ± 3.18) mmHg and (38.78 ± 4.23) mmHg vs. (43.67 ± 3.65) mmHg, and there were statistical differences ( P<0.05). Conclusions:HFNC is effective in mechanical ventilation withdrawal of premature infants, which can reduce complications and improve blood gas analysis.

OBJECTIVETo observe the effect of oversized occluder on endothelialization post percutaneous closure of experimental atrial septal defect (ASD) in dogs.

METHODSASD was established with the help of transthoracic echocardiography in 18 dogs. ASD size was (6.0 ± 0.2) mm. Dogs were randomly divided into normal size group (implanted with 8 mm occlude, n = 9) and oversized group (implanted with 12 mm occluder, n = 9). Dogs were randomly killed at 3, 6 and 14 months after percutaneous closure. The endothelialization process on device surface was observed by scanning electron microscope.

RESULTSFour animals died around 1 month post procedure. Microscopic sections from normal group showed nearly complete endothelialization at 3 months after device implantation and complete endothelialization at 6 and 14 months after device implantation. While microscopic sections showed lack of endothelialization at 3 months post implantation, nearly endothelialization at 6 months, and complete endothelialization at 14 months after device implantation in oversized group.

CONCLUSIONIncomplete endothelialization of occluder surface is observed at 6 months after implantation of an oversized ASD occluder device in this model.