BACKGROUND: Newborn neurons have bean shown to induce long-term potentiation (LTP). Activation of N-methyl-D-aspartic acid (NMDA) receptor subunit NR2B plays an important role in mature neurons-induced LTP. But there have been no reports addressing on the effects of NR2B activation on newborn neuron-induced LTP.OBJECTIVE: To investigate the effects of NR2B receptor antagonist Ro25-6981 on LTP induced by newborn neurons in adult rat dentate gyrus.DESIGN, TIME AND SETTING: An electrophysiological recording trial was performed at the Department of Neuroblology,Shanxi Medical University from February to June 2007.MATERIALS: Twenty-six male Wistar rats, aged 3 months, were provided by Laboratory Animal Center, Shanxi Medical University.METHODS: Following sacrifice for brain harvesting under anesthesia, the hippocempus was taken to preparation of 400 μ mol/L brain slices. Using extracellular field potential recordings, low-frequency stimulation was performed in the medial molecular layer of dentate gyrus with insulated bipolar tungsten electrodes. After having stable recordings, LTP was induced under high-frequency tetanic stimulation. LTP was induced with a protocol developed previously (4 trains, 500 ms each, 100 Hz within the train, repeated every 20 s). Only those slices which produced the field excitatory postsynaptic potential of 1 mV or cerebrospinal fluid (ACSF)-induced LTP (ACSF-LTP): brain slices were divided into 2 groups: ACSF group, in which, slices were continuously perfused using ACSF bubbled with 95% O2 and 5% CO2; ACSF+ Ro25-6981 group: a 10-minute treatment with 3μ mol/L Ro25-6981 was performed prior to tetanic stimulation, and the remaining procedures were the same as ACSF divided into 2 groups: BIC group: a 10-minute treatment with 10 μmol/L BIC was performed prior to titanic stimulation; BIC+Ro25-6981 group: 3μ mol/L Ro25-6981 and 10μ mol/L BIC were simultaneously perfused 10 minutes prior to tetanic stimulation.MAIN OUTCOME MEASURES: LTP recording results.minutes of titanic stimulation, LTP was (164.67±2.40)% and (147.56±6.63)% in the BIC and BIC+ Ro25-6981 groups,respectively, and a significant difference existed between the two groups (P ＜ 0.05).

Objective To evaluate the preliminary outcome of cannulated screw internal fixation in treatment of the tarsometatarsal joint injuries.Methods From January 2005 to October 2010,21 patients(14 males and 7 females)with the tarsometatarsal joint injuries were treated.Their age ranged from 21 to 62 years(average 38.2 years).According to anatomical three-column classification,there were four patients with single medial column injury,four with medial and middle column injuries,three with middle and lateral column injuries,two with single lateral column injury and eight with three column injuries.The injury causes included traffic injury in nine patients,machine injury in eight and fall from height injury in four.The period from injury to admission was 2-15 hours(mean 5 hours).During operation,open reduction was performed,followed by internal fixation with the cannulated screw.X-ray examination was done in the regular follow-up and function was evaluated by using Maryland scoring system.Results Of all,19 patients were followed up for 4-47 months(mean 20 months),which showed no infection,loosing or breakage of the internal fixation.According to the Maryland scoring system,the clinical outcome was rated as excellent in eight patients,good in seven,fair in two and poor in two,with excellence rate of 79％.Conclusions The three-column theory plays an important role in clinical diagnosis and therapy of the tarsometatarsal joint injuries.Open reduction and cannulated screw internal fixation may attain satisfactory clinical results in treatment of the tarsometatarsal joint injuries.