Objective To evaluate the mitochondrial function of chondrocytes in Kashin-Beck disease (KBD) patients and its correlation with age.Methods Mitochondrial function was evaluated by analyzing the activities of respiratory chain enzyme complexes and citrate synthase (CS),intracellular adenosine triphosphate (ATP)contents, changes in mitochondrial membrane potential (ΔΨm),as well as the intracellular reactive oxygen species (ROS) contents.Correlation of mitodhondrial function and age was analyzed with linear regression.Results Activities of complexes Ⅱ (P = 0.001 ),Ⅲ (P = 0.005 )and Ⅳ (P = 0.005 )were reduced in KBD articular chondrocytes compared with cells from normal controls.However,the mitochondrial mass was increased in KBD samples. Cultured KBD chondrocytes had reduced cellular ATP level (P = 0.001 )and mitochondrial membrane potential (P =0.001),but increased citrate synthase activity (P =0.04)and intracellular ROS level (P <0.001).We found no correlation between mitochondrial function and donor age either in normal or in KBD chondrocytes. Conclusion Mitochondrial function is altered in articular chondrocytes of KBD,and no correlation was found between mitochondrial function and donor age.

Objective To investigate the effect of intravenous infusion of hyper-oxygenated solution (HOS) on small intestinal ischemia-reperfusion (I/R) injury in rabbits.Methods Twenty-four rabbits of both sexes,weighing 2.5-3.2 kg,were randomly divided into 3 groups ( n =8 each):sham operation group (group S),I/R group,and HOS group.Small intestinal I/R was produced by clamping the superior mesenteric artery (SMA) for 1 h followed by 2 h of reperfusion in I/R and HOS groups,while the SMA was only clamped in group S.HOS was infused intravenously at a rate of 20 ml· kg-1 ·h -1 via the auricular vein starting from the time immediately after clamping the SMA in group HOS and the equal volume of normal saline was infused instead of HOS in group I/R.Blood samples were obtained from the inferior vena cava at 2 h of reperfusion to detect the concentration of serum lactic acid.The animals were then sacrificed and the small intestine was removed for determination of the malondialdehyde (MDA) content,and activities of superoxide dismutase (SOD),catalase (CAT) and glutathione peroxidase (GSH-Px) in intestinal tissues and for microscopic examination.The pathological changes of the intestinal epithelia were observed and the damage.to the mucous membrane was scored.The internal organs were removed and bacterial translocation from gut to the internal organs was observed.Results Compared with group S,the level of MDA and lactic acid,and rate of bacterial translocation were significantly increased,and the activities of SOD,CAT and GSH-Px were significantly decreased in groups I/R and HOS ( P ＜ 0.05).Compared with group I/R,the level of MDA and lactic acid,rate of bacterial translocation,and activities of SOD,CAT and GSH-Px were significantly decreased in group HOS ( P ＜ 0.05).Conclusion Intravenous infusion of HOS can reduce small intestinal I/R injury in rabbits.

Objective To explore the necessity and function of the sustentaculum tali screw placement for the treatment of Sanders type Ⅱ calcaneal fracture.Methods The data of Dicom that CT scan with bone was input into Mimics 12.0 software and Ansys 13.0 software for construction of calcaneus three-dimensional finite element model.Then,this model was imported into Solidworks 2010 software.Type Ⅱ calcaneal fracture model was established according to Sanders type cutting of calcaneus.Geometric parameters of AO calcaneal plate and screws were imported to the Solidworks 2010 software.Two internal fixation simulations were established based on the calcaneal model.In one model,the steel was placed on the outside with bone and the cancellous' bone screws were infiltrated respectively into the vertical bone since two screw holes which under the articular surface behind the steel plate,two screw holes which rear of the steel plate,a screw hole of the below calcaneus,two screw holes which in front of steel plate.In another model,a cortical bone screw was infiltrated into the sustentaculum tali through the bottom screw hole of articular surface of the steel plate.The two internal fixation models were loaded under the same condition,and non linear finite element analysis was carried out.The stress distribution in the two internal fixation models was calculated respectively.Results The maximum principal stress focused on the cortical bone of sustentaculum tali in both of the models under the same condition of loading.Bone joint displacement,maximum principal stress of calcaneal and internal fixation system in the model with sustentaculum screw fixation were smaller than that in the model without sustentaculum screw fixation.The stress in the model with sustentaculum screw fixation was more dispersed.Conclusion The placement of sustentaculum tali screw is essential for fixation of type Ⅱ calcaneal fracture to achieve the biomechanical stability and can be used in clinical.

Objective To investigate the method to isolate and culture hepatic stellate cells ( HSCs) for studying the cellular mechanisms of hepatic frbrosis.Methods HSCs were isolated by nycodenz density gradient centrifugation after the hepatocytes obtained from adult male gebils were digested with pronase, collagenase and DNase, infused via portal vein.The cell viability was determined by trypan blue exclusion test.The purity of HSCs was identified by detectingα-SMA, desmin immunohistochemical staining.Results The yield rate of HSCs was 0.5~1 ×107 per gerbil liver, and the cell viability was more than 90%.The percentage ofα-SMA-positive cells was more than 75%after 3 days primary culture and almost 100% cells were α-SMA and desmin positive in passage culture.Conclusion The successful protocol of primary culture of Mongolian gerbil HSC provide a technical support for research of relevant liver diseases and drug development in the future.

Objective To examine the changes of serum total and high density lipoprotein cholesterol during whole blood incubation and to investigate the possible mechanisms responsible for the instability.Methods A method for the measurement of serum total cholesterol (TC), total free cholesterol (TFC), high density lipoprotein cholesterol (HDLC) and high density lipoprotein free cholesterol (HDLFC) by high performance liquid chromatography (HPLC) was developed. Whole blood specimens were incubated at 25℃ and 4℃ for various period of time and serum TC, TFC, HDLC and HDLFC were measured.Results The new HPLC method showed a mean within-run CV of 0.22%~0.51%. The averaged changes during the incubations ranged 0.6%~2.0% for TC and 2.0%~4.1% for HDLC.Conclusion An HPLC method has been established that is highly precise and can be used for detecting subtle cholesterol changes in biological samples. Different cholesterol exchanges or transfers between blood cells and lipoproteins exist during various incubations. Prolonged whole blood storage that causes serum TC and HDLC changes should be avoided in clinical lipid measurements.

Asian Continental Ancestry Group ; genetics ; Carcinoma, Hepatocellular ; genetics ; China ; Gene Frequency ; Genetic Predisposition to Disease ; Humans ; Liver Neoplasms ; genetics ; Mongolia ; Polymorphism, Single Nucleotide

Objective To observe the changes of learning function and neuron-specific enolase (NSE)protein of both brian and serum in rats after intermittent hypoxia,and explore the relation between NSE protein and learning and memory function.Methods Male Wistar adult rats(n=48)were randomly divided into control group (UC group) and 7.5％ chronic intermittent hypoxia group (7.5％CIH group).7.5％ chronic intermittent hypoxia model in rats were simalated by using the self-made cabin of intermittent hypoxia.At the 2nd,4th,6th,and 8th week respectively,learning and memory function in rat was tested by Morris water maze in two groups.The level of NSE protein in hippocampal CA1 region was detected by immunohistochemical method,and was detected in serum of rats by using enzyme-linked immunosorbent adsorption method.Results Compared with the control group,7.5％ CIH group at the 2nd,4th,6th,and 8th week in rats from the second week of the escape latency time was 44.13± 2.84) s,(50.35 ± 1.96) s,(57.47 ± 1.66) s,(62.85 ± 1.80) s,and across the target quadrant time was 48.81 ± 2.09) s,(42.04± 1.84) s,(36.82± 2.07) s,(31.81 ± 1.68) s.From the first two weeks,the longer the hypoxia time prolonged,the longer the rat's escapedlatency (P＜0.05) and the shorter the rats acrossed the target quadrant (P ＜0.05).7.5％ CIH group of hippocampal CA1 neurons NSE protein at the 2nd,4th,6th,and 8th week was (9.69±1.37),17.10± 1.87),(24.79± 3.51),(34.16±5.35),respectively,and serum NSE protein at the 2nd,4th,6th,and 8th week respectively was (6.03±0.91) μg/L,(11.04± 1.89) μg/L,(16.39± 1.00) μg/L,(24.22±3.73) μg/L,both of which were more than the control group.The difference was statistically significant (P＜0.05).7.5％ CIH group of hippocampal CA1 neurons and serum NSE protein expression were significant time differences,and gradually increased over time.The difference was statistically significant (P＜0.05).Positive NSE protein expression in hippocampal CA1 region relative NSE and serum protein expression values were positively correlated (r=0.94,P ＜0.01).But in control group NSE protein expression did not exist time difference (P＞0.05).Conclusion Intermittent hypoxia can cause NSE levels significant increase in serum and brain tissue,and the dynamic changes of them can reflect severity of learning and memory impairement in rat.

OBJECTIVETo study the therapeutic method and clinical effect of domestic locking plate for treating fracture of the tubiform bone through a minimal incision and bridging fixation.

METHODSAmong 40 patients with fracture of the tubiform bone, 29 patients were male and 11 patients were female, aged from 29 to 69 years, with the average of 38.27 years. Among 34 patients with closed fracture, 7 cases were type A, 10 cases type B, 17 cases type C according to AO/ASIF classification. Among 6 patients with open fracture, 2 cases were type I, 4 cases were type II according to Gustilo classification. These patients were treated with a small incision after manipulative reduction. Locking plate and 3.5 mm diameter Kirschner wire were used to maintain the reduction and through the C-arm X-ray machine to check and adjust the position, screw were locked to bridging fixation at last.

RESULTSForty cases were followed up in 6 months on average (ranging from 4 to 10 months). The average time of union of fracture was 4.6 months (ranging from 3 to 8 months). According to Ovadia typing, the results were excellent in 16 cases, good in 20 cases, fair in 3 cases,poor in 1 case. The excellent and good rate was 90%.

CONCLUSIONSThe domestic locking plate is suitable for patients with osteoporosis and comminuted fracture because of the advantages of reliable fixation and low price. It could achieve the same effect of minimal invasive as LISS (less invasive stabilizing system) plate through the improvement of operative method.

Adult ; Aged ; Bone Plates ; Female ; Fracture Fixation ; methods ; Humans ; Male ; Middle Aged ; Minimally Invasive Surgical Procedures ; methods

Ion channels mediate ion transport across membranes, and play vital roles in processes of matter exchange, energy transfer and signal transduction in living organisms. Recently, structural studies of ion channels have greatly advanced our understanding of their ion selectivity and gating mechanisms. Structural studies of voltage-gated potassium channels elucidate the structural basis for potassium selectivity and voltage-gating mechanism; structural studies of voltage-gated sodium channels reveal their slow and fast inactivation mechanisms; and structural studies of transient receptor potential (TRP) channels provide complex and diverse structures of TRP channels, and their ligand gating mechanisms. In the article we summarize recent progress on ion channel structural biology, and outlook the prospect of ion channel structural biology in the future.
Ion Channel Gating ; physiology ; Ion Channels ; Voltage-Gated Sodium Channels ; chemistry ; metabolism

Under natural environments, plants and algae have evolved various photosynthetic acclimation mechanisms in response to the constantly changing light conditions. The state transition and long-term response processes in photosynthetic acclimation involve remodeling and composition alteration of thylakoid membrane. A chloroplast protein kinase named Stt7/STN7 has been found to have pivotal roles in both state transition and long-term response. Here we report the crystal structures of the kinase domain of a putative Stt7/STN7 homolog from Micromonas sp. RCC299 (MsStt7d) in the apo form and in complex with various nucleotide substrates. MsStt7d adopts a canonical protein kinase fold and contains all the essential residues at the active site. A novel hairpin motif, found to be a conserved feature of the Stt7/STN7 family and indispensable for the kinase stability, interacts with the activation loop and fixes it in an active conformation. We have also demonstrated that MsStt7d is a dualspecifi city kinase that phosphorylates both Thr and Tyr residues. Moreover, preliminary in vitro data suggest that it might be capable of phosphorylating a consensus N-terminal pentapeptide of light-harvesting proteins Micromonas Lhcp4 and Arabidopsis Lhcb1 directly. The potential peptide/protein substrate binding site is predicted based on the location of a pseudo-substrate contributed by the adjacent molecule within the crystallographic dimer. The structural and biochemical data presented here provide a framework for an improved understanding on the role of Stt7/STN7 in photosynthetic acclimation.
Amino Acid Sequence ; Amino Acid Substitution ; Arabidopsis ; metabolism ; Arabidopsis Proteins ; chemistry ; genetics ; metabolism ; Binding Sites ; Catalytic Domain ; Chlorophyta ; enzymology ; Crystallography, X-Ray ; Cyclin-Dependent Kinase 2 ; chemistry ; metabolism ; Molecular Sequence Data ; Phosphorylation ; Protein Structure, Secondary ; Protein-Serine-Threonine Kinases ; chemistry ; genetics ; metabolism ; Sequence Alignment ; Substrate Specificity