Objective To investigate whether cystatin C-based prediction equations for GFR estimation are superior to SCr-based prediction equations.Methods One hundred and ninety-eight consecutive patients (85 males,113 females,average age 66.5 years) who underwent GFR measurement with 99TcmDTPA and serum cystatin C and SCr tests were included in this retrospective study.GFR,serum cystatin C and SCr concentrations were determined by the Gates method (measured GFR),the particle-enhanced turbidimetric immunoassay,and the Jaffe method,respectively.Eight different equations (6 equations based on the serum cystatin C,and the other 2 based on SCr) were used to estimate GFR values,and the results were compared with that of the Gates method.Patients were divided into different groups according to the measured GFR (normalized to body surface area,1.73 m-2):normal renal function,mild,moderate or severe renal impairment groups.One-way analysis of variance and the least significant difference t test were used to compare the estimated GFR,andx2 test was used to compare the diagnostic efficiencies of different GFR estimation equations.Results Among 198 patients,159 cases were with renal impairment (78 mild,58 moderate,23 severe),and the other 39 cases were with normal renal function.For patients with moderate or severe renal impairment,the estimated GFR calculated by the Tan formula was not different from the measured GFR (severe:(20.7±7.4) ml · min-1 vs (19.9±8.2) ml · min-1; F=6.75,t＜1.05; moderate:(42.1±14.4) ml· min-1 vs (46.8±9.2) ml· min-1; F=10.49,t＜1.63; both P＞0.05),and it had the least error compared with the measured GFR (severe:(12.3±7.0) ％ ; moderate:(17.9± 13.0) ％).For the patients with mild renal impairment and normal renal function,the estimated GFR calculated by the Tan formula was not valuable.For the diagnosis of renal impairment,the sensitivity and accuracy of the modification of diet in renal disease (MDRD) formula were 66.0％(105/159) and 71.2％(141/198),respectively,and those of the chronic kidney disease-epidemiology collaboration (CKD-EPI) formula were 70.4％ (112/ 159) and 73.7％(146/198),respectively.The sensitivities and accuracies of the cystatin C-based formulas (≥83.6％ (133/159) and ≥79.3％(157/198),respectively) were higher than those of MDRD formula and CKD-EPI formula (x2 ≥23.50,all P＜0.01).For the diagnosis of chronic kidney disease (including 81 patients with moderate and severe renal impairment),the sensitivities of cystatin C-based prediction equations (≥ 86.4％ (70/81)) were higher than those of the MDRD formula and the CKD-EPI formula (76.5％ (62/81),79.0％ (64/81)),but the accuracies were slightly lower (Tan formula:80.3％ (159/198),x2≥ 56.42,all P＜0.05).Conclusion The Tan formula may be more suitable for the GFR estimation than the MDRD formula and CKD-EPI formula in the patients with severe or moderate renal impairment (serum cystatin C≥ 1.55 mg/L),but it may not be reliable for the patients with mild renal impairment and normal renal function.

Lappaconitine (LA) 0. 5 mg? kg-1had significant antagonistic action on the ar-rythmia induced by 3-acetylaconitine ( AA ) 0.07 mg?kg-1in rat. When LA and AA were used in combination (7:1) in mice, the analgesic activity of AA was not influenced marked-ly by LA but the LD50 of AA was increased by 50% ,therefore the therapeutic index of AA was increased and the margin of safety was widened.

Objective To determine the effect of propofol on calcium homeostasis mitochondria in rabbit cardiac muscle subjected to ischemia reperfusion under the protection of cardioplegic solution Methods Twenty four healthy New Zealand white rabbits weighing 1 9 2 2kg were randomly divided into four equal groups of six rabbits each: control group(C);ischemia group(I); low concentration propofol +ischemia(LP) and high concentration propofol +ischemia(HP) The animals were anesthetized with intraperitoneal thiopental 25mg/kg and heparinized Chest was quickly opened and heart excised and connected to Langgendorff preparation The isolated heart was passively perfused via aorta In group LP and HP the perfusate contained propofol 50?mol/L and 200?mol/L respectively When the developed pressure of left ventricle and heat rate were stabilized (about 20 min after perfusion was stared),in group C perfusion was continued for another 90 min at normothermia (37℃?0 2℃)and 7 84kPa perfusion pressure In group I, LP and HP perfusion was stopped and cardiac arrest was induced by 20ml high potassium cardioplegic solution (4℃)and heart was immersed in 8℃ 14℃ normal saline Cardioplegic solution was perfused every 20min After 60 min cardiac arrest the heart was reperfused for another 30min The heart was then removed and immediately kept in 0℃ hemogeneous medium A slice of cardiac muscle was taken from apex of the heart Mitochondrial structure was observed using electron microscope Mitochondrial matrix calcium concentration, mitochondrial calcium uptake in high calcium enviroment (2 5 mmol/L CaCl 2 was added ) and calcium release (when sodium ion was added) were determined Results Propofol at concentration of either 50?mol/L or 200?mol/L had no effect on mitochondrial calcium homeostasis after ischemia reperfusion The damage to mitochondrial structure in propofol groups was milder than that in ischemia group Conclusions Propofol at clinical concentration can relieve the mitochondrial permeability transition pore opening at reperfusion stage The mechanism is not through inhibition of mitochondrial calcium overload, probably a result of diminished oxidative stress

BACKGROUND:The main factors that influence revision of acetabular bone defects include evaluation of acetabular bone defects,reconstruction of acetabulum and appropriate acetabular cups used in revision.OBJECTIVE:The review from the three aspects will help to choose an appropriate cup in revision and to formulate the best revision protocols.METHODS:A computer-based online search of PubMed was performed for English articles published from January 1900 to June 2009 with the key words of acetabulum,revision,bone defect,in English and Chinese.Clinical studies published in core periodicals of the latest twenty years were reviewed.Articles regarding primary joint replacement,femoral prosthesis revision and animal experiments were excluded.RESULTS AND CONCLUSION:A total of 61 articles were analyzed,31 were excluded,and 30 mainly published in 5 years,were included.Reconstruction of acetabular bone structure,restoration of original rotation center of hip joint are key factors for repair.Moreover,appropriate prosthesis further benefits the repair effect.Bone transplantation for bone defect and cementedless prosthesis have become favorable methods for revision of acetabular bone defects.

An electro-acupuncture stimulator for hemiplegia rehabilitation is designed, which adopts 51 series of SCMs and CPLD as the control unit to fulfill parameter setup, numerical display and separated multi-channel output.

Objective:To study heart mitochondrial calcium homeostasis during ischemia- reperfusion under the protection of cardioplegic solution.Methods:Isolated perfused rabbits hearts were subjected to global ischem ia in the presence of cold cardioplegic solution for an hour and reperfused for half an hour.Electron m icroscope was used to observe the change of mitochondrial structure.Heart m itochondria was isolated and Fura2 - AM was used as the indicator of matrix concentration of calcium([Ca2 + ]m) to m easure[Ca2 + ]m,the intake and outtake ability of the calcium when m itochondria was at high calcium concentration liquid or high natrium concentration liquid.Results:[Ca2 + ]m increased significantly but mitochondria was still able to uptake calcium and release calcium of m atrix.There was some electron- dense deposit in mitochondria and the injury of mitochondria could be seen by electron microscope.Conclusion:The reason for mitochondria calcium overload at the beginning of reperfusion include physiological and pathological calcium uptake,which ends after30 min reperfusion under the protection of cardioplegic solution. [

Objective To analyze and evaluate a new acetabular revision component with three wings. Methods The finite-element models of a new acetabular component and acetabulum with bone loss were established to calculate the interface stresses during a normal gait cycle with use of the finite-element formulations. Results The finite-element analysis demonstrated that stress and strain at the interfaces of bone-shell and metal-polyethylene liner had the same direction of change but no remarkable difference between them. In the study, the result indicated increased contact stresses with an increased joint load and orientation. The peak stress was tested at the second stage of gait cycle. The stress of wings increased gradually from rim to root. Its peak stress that was significantly lower than yield force of the Co-Cr alloy was at the joint between the wing and the shell. The stress of graft had the same change rule as the joint force. The part of graft near to acetabular component was subjected to higher stress conditions. Conclusion The hip forces can transfer from acetabular component and implant to acetabulum. The result of the finite-element analysis underlined the importance of wings of the new acetabular component. The wing can help to improve the antitorsion ability of acetabular component and to minimize its aseptic loosening rate. Therefore, based on results of this study and clinical application, the acetabular component with wings is known a viable means for acetabular revision in the presence of bone loss. But further research is needed as to this acetabular component.

BACKGROUND:Alternative implants affect stability of prostheses,and freeze-dried bone allografts are most selected as implants.The crack between grafts and host bone is unavoidable,which would weaken the bone integration.Bone cement can fill the cracks quickly and completely,however,the effects of bone cement on the stress of prostheses and its own remains poorly understood.OBJECTIVE:To evaluate the effect of the different grafting for bone loss in the presence of the new acetabular component with wings at the time of acetabular revision.METHODS:The finite-element models of acetabular component with three wings and acetabulum with bone loss were established.Following prostheses implantation,the gaps were filled with bone cement and freeze-dried bone allograft,respectively,stress of the graft and its effect on prostheses were analyzed under 2 158 N and 426 N acetabular loads.RESULTS AND CONCLUSION:The finite-element analysis demonstrated that stress and strain at the interfaces of bone-shell and metal-polyethylene liner had the same direction of change but no significant difference between them.In the study,the result indicated increased contact stresses with an increased hip force and orientation.The stress of wings increased gradually from rim to root.Its peak stress was at the joint between the wing and the shell.The different grafts did not affect the stress of the acetabular component.But the stress of bone cement was significantly higher than that of particulate bone.The study demonstrated that change of the graft could not make remarkable effect on the stress of the acetabular component.But the stress of bone cement increased significantly.The result of the finite-element analysis indicated that particulate bone graft is benefit to improving itsstability and to minimize aseptic loosening rate of acetabular component.

Alternative designs have been explored in an attempt to improve the longevity of acetabular prostheses in revision surgery. Many studies had been designed to test the result of the extra-large uncemented hemispherical acetabular components used for acetabular revision in the presence of bone loss. A clinical study of a new acetabular component consisting of a porous metal shell with three wings and an all-polyethylene liner had attained a satisfying result. The purpose of this study was to evaluate the new acetabular component by comparison with the hemispherical acetabular component. The finite-element models of the two acetabular components and the acetabulum in the presence of bone loss were established to calculate the interface stresses during a normal gait cycle with use of the finite-element formulations. Results of the finite-element analysis demonstrated that stress and strain of the two acetabular components had the same direction of change, but the new component had higher stress at the root of wings. In the study, the result indicated reduced contact stresses with a reduced abduction angle of wings. The stress was lower in the new acetabular component of 15° angle of wings compared with the new acetabularcomponent of 30°of wings and hemispherical acetabular component (P < 0.05). The stress of acetabular component with wings showed no remarkable difference by comparison with the extra-large uncemented hemispherical acetabular component. Reducing abduction angle of wings seemed to be a viable means of reducing the stress of the acetabular component while improving its stability.

BACKGROUND: Recently, many researches suggest that transcranial magnetic stimulation has effect on learning and memory. Moreover, the effects of magnetic fields simulating electroencephalogram (EEG) rhythm on memory have been investigated.OBJECTIVE: To explore the effect of magnetic field simulating EEG rhythm on memory retrieval ability and its mechanism.DESIGN: Randomized controlled study.SETTING: Department of Medical Imaging, Tianjin Medical University,and School of Precision Instrument & Photoelectronic Engineering, Tianjin University.MATERIALS: The experiment was conducted at the Electroscopic Center of TianjSn Medical University and Laboratory of Biomedical Engineering Department of Tianjin University from February 2002 to February 2004.Totally 25 Wistar rats and 5 domestic cats were selected from the Experimental Animal Center of Tianjin Medical University.INTERVENTIONS: All the 25 Wister rats were randomly divided into 5 group, 4 experimental groups and one control group with 5 rats in each group. Magnetic field simulating EEG rhythm was used to stimulate Wistar rats in the 4 experimental groups, but the time and frequency rate were different. Group 1 was stimulated by weak magnetic field with frequency in α rhythm (10 Hz); Group 2 was stimulated by weak magnetic field with frequency in β rhythm (20 Hz); Group 3 was stimulated by weak magnetic field with frequency changing from α to β rhythm; and Group 4 was stimulated by weak magnetic field with frequency changing from β to α rhythm. Memory retrieval ability and changes of neurotransmitters in the brain were recorded. Five cats were treated with weak magnetic field with frequency changing from α to β rhythm for 20 minutes, and the changes of EEG power spectra before and after stimulation were compared.information from long-term memory was tested with modified cross maze;hippocampus of the rats was measured with high performance liquid multiple-channel electrophysiological recording device.Comparison of memory retrieval ability: Memory retrieval ability in Group 2 and Group 4 was obviously higher than that in control group 5 hours after Content ofdopamine (DA) in rats' cerebral hippocampus: It was obviously higher in the 4 experimental groups than in control group [(192.72±18.66,percentage of power spectrum of β rhythm was increased after stimulation [(23.0±3.4, 14.2±1.3) %.].CONCLUSION: Most of the weak magnetic fields simulating EEG rhythm of human brain can decrease the retrieval of long-term memory, but magnetic field with special rhythm may increase memory retrieval ability.All the effects are related to the release of hippocampal neurotransmitters which is mediated by the change of intracellular calcium ([Ca2+]i) and synaptic vesicle.