AIM and METHODS: The ratio of mitochondrial DNA (mtDNA) deletion was measured to find the relationship between mtDNA deletion and aged learning and memory deficit. The aged rats were divided into two groups, aged learning and memory deficit group and aged learning and memory normal group. The ratio of mtDNA deletion was measured by dilution polymerase chain reaction. RESULTS: There are deleted mtDNA (about 4834 bp) in the cerebral cortex, hippocampus and cerebellum of both young and aged rats. The ratios of deleted mtDNA were similar in the cerebral cortex,hippocampus and cerebellum of young rats (about 0.00018%). The ratio mtDNA of aged learning and memory normal rats had increased by five-fold in the cerebral cortex and hippocampus, or one-fold in the cerebellum over young rats. The ratio of aged learning and memory dificit rats had increased by one-fold in the cerebral cortex or 0.8-fold in the hippocampus or two-fold in the cerebellum over aged learning and memory normal rats.CONCLUSIONS: There was really the increase of mtDNA in aging rat brain. And this increase was double in amount in aged learning and memory deficit rats compared to the normal learning and memory aged rats. It is suggested that the mtDNA deletions in the brain regions associated with learning and memory may be contributed to the cellular and molecular mechanism of learning and memory deicit with aged rats.

Objective To evaluate the effect of monosialoganglioside (GM-1) on hippocampal protein kinase B (Akt) /glycogen synthase kinase 3β (GSK-3β) signaling pathway in the rats undergoing cardiopulmonary bypass (CPB).Methods Eighteen healthy male Sprague-Dawley rats, aged 6 months, weighing 400-500 g, were randomly divided into 3 groups (n =6 each) using a random number table:control group (group C), CPB group and GM-1 group.GM-1 20 mg/kg was added to the priming solution in group GM-1, while the equal volume of normal saline was given in group CPB.At 3 h after termination of CPB, blood samples were taken from the jugular vein for determination of plasma neuron-specific enolase (NSE) and S-100β protein concentrations using enzyme-linked immunosorbent assay.After blood sampling, the rats were sacrificed, and the hippocampi were isolated for microscopic examination of the ultrastructure of the hippocampal neurons (with electron microscope), and for detection of neuronal apoptosis (with light microscope) and phosphorylation of Akt and GSK-3β (by Western blot).Results Compared with group C, the concentrations of plasma NSE and S-100β protein, and the number of apoptotic neurons were significantly increased in CPB and GM-1 groups, the phosphorylation of Akt and GSK-3β was decreased in group CPB, and the phosphorylation of Akt and GSK-3β was increased in group GM-1 (P＜0.05).Compared with group CPB, the concentrations of plasma NSE and S-100β protein, and the number of apoptotic neurons were significantly decreased, the phosphorylation of Akt and GSK-3β was increased (P＜0.05), and the pathological changes were reduced in group GM-1.Conclusion GM-1 can reduce apoptosis in hippocampal neurons through activating Akt/GSK-3β signaling pathway, thus mitigating CPB-induced brain injury in rats.

Objective To investigate the effect of monosialoganglioside GM-1 on cardiopulmonary bypass (CPB)-induced brain injury in rats.Methods Twenty-seven adult male Sprague-Dawley rats,weighing 350-450 g,aged 15 months,were randomly divided into 3 groups (n=9 each): control group (C group),CPB group and GM-1 group.The animals were anesthetized with chloral hydrate,tracheostomized and mechanically ventilated.Right common carotid and right jugular vein were cannulated for closed-chest CPB.In groups CPB and GM-1,the rats underwent 1 h CPB.GM-1 20 mg/kg was added to the priming solution in group GM-1,while the equal volume of normal saline was given in group CPB.The animals were sacrificed at 3 h after termination of CPB or 3 h after the end of ventilation in group C,the brains were removed and the hippocampi isolated for microscopic examination and for determination of apoptosis (using TUNEL) and Bax and Bcl-2 protein expression (by immunohistochemistry and Western blot).Results Compared with group C,the number of apoptotic neurons and ratio of Bax/Bcl-2 were significantly increased,and the expression of Bcl-2 and Bax protein was up-regulated in groups CPB and GM-1 (P ＜ 0.05).Compared with group CPB,the number of apoptotic neurons and ratio of Bax/Bcl-2 were significantly decreased,the expression of Bax protein was down-regulated and the expression of Bcl-2 protein was up-regulated in group GM-1.The pathological changes were severe in group CPB and attenuated in group GM-1.Conclusion GM-1 can attenuate CPB-induced brain injury in rats and inhibition of the apoptosis in neurons may be involved in the mechanism.

Objective To investigate the expression profile of human genes in response to acute sodium arsenite treatment by cDNA microarray. Methods The RNA was purified from the L-02 cells without and with arsenite sodium induction for 2 hours, 15 hours and 24 hours, respectively. Results The hybridization patterns were different between every interval of arsenite induction. Expression of hCYR61 increased after 2 hours' induction, but decreased after 15 hours and 24 hours. Expression of metallothionein Ⅳ and Ⅲ elevated at the whole induction phase. HSP86 was up-regulated after 15 hours and 24 hours' induction, but it did not alter at two hours' induction. Conclusion When exposed to arsenite, the cells are under a meet-an-emergency situation to synthesize the most necessary protein and inhibit synthesis of unessential proteins.

Objective To explore the accuracy and clinical efficacy of advanced 3D printing navigation templates in assisting placement of atlantoaxial pedicle screw.Methods A retrospective analysis was carried out on 49 cases of patients with atlanto-axial vertebral fractures and dislocations between June 2013 and June 2016,and all of them were given posterior incision,reduction and internal fixation of atlantoaxial pedicle screw.The patients were divided into advanced 3D printing navigation template group (14 cases),early 3D printing navigation template group (16 cases),and routine pedicle screw placement group (19 cases).Atlantoaxial CT data of patients in advanced 3D printing navigation template group and early 3D printing navigation template group were input into Mimics 17.0,then advanced 3D printing navigation template group and early 3D printing navigation which were used in clinic surgery were designed and printed.The relationship between positions of pedicle screw with the pedicle and bone cortex in plain CT image was observed after operation.The quality of the screw position was assessed and the accuracy of three kinds of screwing methods was compared.The accuracy of the screwing angle was assessed by comparing with the differences between the preoperative designed channel inclination angle and postoperative actual screwing angle.Three groups were compared for differences between operation time,intraoperative blood loss,and scores of cervical nerve scale and visual analogue scale (VAS) of neck and shoulder pain by Japanese Orthopaedic Association (JOA).Results All 49 cases of patients successfully completed the surgery.Patients of the routine pedicle screw placement group,early 3D group and advanced 3D group correspond operation time for 141.2±20.7 min,112.5±12.1 min and 103.1±10.4 min,intraoperative blood loss for 314.0±81.4 ml,243.6±71.2 ml and 181.0+59.1 ml;total accuracy of screwing for 75.0％ (54/72),93.75 ％ (60/64) and 96.43 ％ (54/56).There were statistically significant differences among the routine group,3D group and advanced 3D group in the mentioned programs.There were no statistical differences between advanced 3D group and 3D group in the inclination angle and head tilt angle with the pre-designed values,while there was statistically significant difference between the routine group and the pre-designed value.The accuracy of the inclination angle and bead tilt angle screwing angle were obviously superior in the advanced 3D group and early 3D group to that of the routine group.There were statistically significant differences between preoperative with postoperative VAS scores and JOA scores in the same group,while there were no statistically significant differences among groups in JOA.But there was statistically significant difference between the routine group and the advanced 3D in VAS,and there was no statistically significant difference between the routine pedicle screw placement group and the early 3D in VAS.All three groups of patients had bony fusion of atlantoaxial vertebral body,without loosening,dislocation and fracture of the internal fixators.Conelusion Advanced 3D printing templates in assisting the surgical treatment for atlantoaxial fracture and dislocation can improve the accuracy of pedicle screwing and safety of the surgery,reduce the surgery risk,and obtain satisfied clinical curative effects.

Objective To investigate the clinical efficacy of asymmetric osteotomy via posterior adjacent vertebrae in the treatment of traumatic thoracolumbar kyphotic scoliotic deformity.Methods A retrospective case series study was conducted on the clinical data of 16 patients with traumatic thoracolumbar kyphotic scoliotic deformity admitted to our department from January 2012 to January 2017.There were 10 males and six females,aged (42.5 ±7.6) years (range,20-62 years).According to the location of injured vertebrae,there were two patients with T11,five with T12,six with L1,and three with L2,all of which had scoliosis deformity and obvious low back pain.All patients underwent asymmetric osteotomy via posterior adjacent vertebrae.The operation time and intraoperative bleeding were recorded.The imaging parameters such as kyphosis Cobb angle,scoliosis Cobb angle,distance between C7 plumbline and central sacral vertebral line (C7-CSVL),and distance between C7 plumbline and sagittal vertical axis (SVA) were measured before and after operation.At the same time,the visual analogue scale (VAS),Oswestry dysfunction index (ODI),and SRS-22 scale were used to evaluate the clinical efficacy.The AISA score was used to evaluate the neurological function recovery before and after operation.Results All patients were followed up for (26.3 ± 16.8) months (range,15-65 months).The operation time was (6.0 ± 1.4) hours (range,4.5-9.0 hours),and the intraoperative bleeding was (900.5 ± 360.8)ml (range,800-1600 ml).The kyphosis Cobb angle was improved from (70.3 ± 9.8) °before operation to (12.2 ± 2.9) ° after operation (P ＜ 0.01).The scoliosis Cobb angle was improved from (47.6 ± 11.6) ° before operation to (4.0 ± 0.9) ° after operation (P ＜ 0.01).The C7-CSVL decreased from preoperative (3.1 ±0.8)cm to postoperative (1.2 ±0.4)cm (P ＜0.01),and the SVA decreased from preoperative (5.0 ± 0.9) cm to postoperative (2.9 ± 0.5) cm (P ＜ 0.01).No severe complications such as spinal cord and nerve injury occurred.The VAS decreased from preoperative (6.8 ± 1.0) to (1.9 ± 0.9) points at the last follow up.The ODI decreased from (54.6 ± 4.2) ％ before operation to (8.1 ± 2.5) ％ at the last follow up.The SRS-22 score was increased from (64.6 ±7.5) points before operation to (87.4 ± 3.2) points at the last follow-up.In terms of the ASIA classification,two patients were improved from grade C to grade D after operation,and six patients were improved from grade D to grade E.Conclusion Asymmetric osteotomy via posterior adjacent vertebrae is safe and effective in the treatment of traumatic thoracolumbar scoliosis,with high correction rate of scoliosis and kyphosis at the same time.

Objective To prepare dual?modality single?photon emission computed tomography (SPECT)?MRI molecular nanoprobes targeting HAb18G/CD147 expressed on breast cancer cell membranes and investigate the physicochemical and biological properties in vitro. Methods Superparamagnetic iron oxide nanoparticles (SPIOs) were prepared by one?pot reaction method as described. The single?chain antibody fragments HAb18F(ab')2 were conjugated to SPIOs via chemical method and then labeled with 125I using Iodogen method. The final 125I?SPIO?HAbF18(ab')2 nanoprobes were purified. SPIOs or 125I?HAb18F(ab')2 were used as control. We carried preliminary evaluation on their physicochemical properties and biological characteristics in vitro: transmission electron microscope (TEM) and dynamic light scattering (DLS) were used to measure these nanoparticle sizes and the hydrodynamic diameters. The MRI T2 transverse relaxation efficiency of these nanoprobes at different Fe2+concentrations were measured with 1.5 T clinical MR scanner. The 125I?SPIO?HAb18F(ab')2 and 125I?HAb18F(ab')2 radiochemical purity were measured by thin layer chromatography and the radio chemical yield was calculated. We also conducted stability tests in vitro and octanol/water partition coefficient experiments. Two breast tumor cell lines, MDA?MB?231 (HAb18G?overexpressing cells,experimental group) and MDA?MB?468 (control), were used for assessment of cells viability at different Fe2 + concentrations (1, 5, 10, 20, 40 μg/ml) by methyl thiazolyl tetrazolium assay. Specific binding experiments in vitro included two parts:magnetic resonance imaging and radionuclide tests, the above?mentioned breast cancer cell lines were incubated with 125I?SPIO?HAb18F(ab')2 nanoprobes respectively and took MDA?MB?231 cells which were not treated as blank group. First comparing the MR signal intensity differences among experimental group, the control group and blank group, then calculated the rate of MRI signal changes;Two breast tumor cell lines, MDA?MB?231 and MDA?MB?468 were incubated with 125I?SPIO?HAb18F(ab')2 nanoprobes too, then measured radioactivity counting byγcounter at different time and calculated the cell binding rates, and did statistical analysis by using one?way ANOVA. Results The SPIOs were fairly homogeneous with an average core size of (10.32±1.30) nm;the SPIO and 125I?SPIO?HAb18F(ab')2 hydrodynamic diameter of 44.80 and 52.64 nm, and MRI scanning showed that the transverse relaxation efficiency of SPIO and 125I?SPIO?HAb18F(ab')2 were 38.79 and 106.73 mM-1 · s-1, respectively. The radio chemical yield of 125I?SPIO?HAbF18(ab')2 and 125I?HAb18F(ab')2 were 41.90% and 85.50%, respectively. The radio chemical yield of the two groups were >95%, suggesting well stability in vitro. The lipo?hydro partition coefficient values were -0.99 ± 0.03 and-1.49 ± 0.08, respectively, which demonstrated that they were both water?soluble substances. Different Fe2+concentrations (1,5,10,20,40μg/ml) of 125I?SPIO?HAb18F(ab')2 on breast cancer cell lines MDA?MB?231 and MDA?MB?468 showed no significant inhibition of cell proliferation (F values were 0.78, 0.66; P values were 0.58, 0.66). The cell?specific binding experiment showed: MRI signal intensity values on experimental group, the control group and the blank group were (1 670 ± 5), (1 930 ± 8), (2 349 ± 14), respectively, significant differences existed among these groups (F=4 408.48,P=0.000), the rate of signal intensity change of experimental group and the control group were 28.87%,17.78%. SPECT:MDA?MB?231 could uptake 125I?SPIO?HAb18F(ab')2, the cell binding rates were (6.52 ± 0.60)% and (10.52 ± 2.04)% in 20 min and 4 h, respectively.Conclusions Our results suggested that the dual?modality SPECT?MRI nanoprobes 125I?SPIO?HAb18F(ab')2 were prepared successfully with good physicochemical properties and biological characteristics in vitro. These dual?modality molecular imaging nano?probes may have potential to improvearly detection and diagnosis of HAb18G/CD147?expressing cancers and to facilitate the development of HAb18G/CD147?directed interventions.

Objective To investigate the effects of xenogenic bone with chitosan/norvancomycin sustained-release biomaterials in treating infectious bone defects in rabbits.Methods Xenogenic bone with chitosan/norvancomycin sustained-release biomaterials was made by electrospinning technique.Rabbit infectious bone defect models were made by Methicillin-resistant Staphylococcus aureus.A successful model was evaluated with the standard of more than three points in Norden score assessment.All models were divided into two groups by random number table method,with eight models in each.The control group was treated with surgical debridement,and the experimental group was implanted with bone particles of xenogenic bone with chitosan/norvancomycin sustained-release system after debridement.Postoperatively,general conditions,X-ray,histological results of HE staining,and bacteriological examination results of the rabbits were observed.Results X-ray showed significant bone defects,sequestration,periosteal reaction,and soft tissue swelling after one month of modeling,with Norden score of (3.84 ± 0.52) points.The general conditions were good and the sinus tracts were healed in experimental group after two months of treatment.The control group demonstrated generally poor conditions with swollen sinus and purulent discharge.Two rabbits were died of sepsis.The pathological scores of tibial were (0.41 ± 0.08) points in experimental group,and (3.27 ± 0.26) points in control group by gross observation.The pathological score of experimental group was significantly lower than control group(P ＜ 0.05).The bone defects were basically repaired in experimental group.The longest diameter of bone defect in experimental group was (0.11 ± 0.02)cm,significantly smaller than (0.48 ± 0.06) cm in control group (P ＜ 0.05).There were no obvious signs of osteomyelitis and the bone defects were well repaired in experimental group.Periosteal reaction,soft tissue swelling,a substantial number of bone destruction,and sequestration were observed in control group.The Norden score was (1.32 ± 0.23) points in experimental group,lower than (5.21 ± 0.48) points in control group(P ＜ 0.05).HE staining showed a large amount of trabecular bone formation,bone cell formation,and fibrous hyperplasia in experimental group,with no obvious signs of infection.On the other hand,infiltration of inflammatory cells,necrotic tissue,and sequestration were observed in control group.The histological score was(0.61 ± 0.10) points in experimental group,lower than (4.21 ± 0.41) points in control group (P ＜0.05).The negative rate of bacterial culture in experimental group was 33％,lower than 100％ in control group (P ＜ 0.05).Conclusion Xenogenic bone with ehitosan/norvancomycin sustained-release biomaterials has excellent effect in infection clearance and bone defect reparation in treatment of infectious bone defects in rabbits.

BACKGROUND:The pedicle navigation template has many advantages,but there are still some problems.For example,poor soft tissue dissection leads to poor adhesion of the pedicle navigation template,resulting in screw path deviation;careful dissection of soft tissue to fit the pedicle navigation template leads to prolonged surgery time and increased bleeding;the design of the pedicle navigation template cannot predict the vertebral rotation and the impact of body position changes,resulting in the poor fitting. OBJECTIVE:To explore the utility of a new 5-point positioning point-contact pedicle navigation template in the case of scoliosis and complex pedicle. METHODS:A total of 20 patients with scoliosis and complicated pedicle admitted to the Department of Spinal Surgery,Guizhou Hospital,Beijing Jishuitan Hospital from February 2020 to February 2023 were selected for scoliosis orthopedics.During the operation,the 5-point positioning point-contact pedicle navigation template was used to guide the screws.According to the inclusion and exclusion criteria,34 cases were matched as the empirical nail placement group,and conventional barehanded nail placement was performed.The time of placement,the amount of bleeding,the number of fluoroscopies,the number of manual diversions,the level and accuracy of pedicle screws,the complications of placement,and the rate of correction of main curvature were compared between the two groups. RESULTS AND CONCLUSION:(1)There were no significant differences in sex,age,coronal Cobb's angle of the main curvature,bending Cobb's angle of the main curvature,pedicle variation,apex rotation,fusion segment,number of screws,level of screws,accuracy of screws,and rate of correction of main curvature between the navigation template group and the empirical nail placement group(P>0.05).(2)Compared with the empirical nail placement group,the navigation template group had more advantages in time of placement(P=0.034),amount of bleeding(P=0.036),number of fluoroscopies(P=0.000)and number of manual diversions(P=0.021).(3)There were 0 cases of screw-related complications in both groups.(4)In conclusion,the 5-point positioning point-contact 3D printing pedicle navigation template has a claw-like structure.It can firmly adapt to various deformities of the lamina articular process,avoid drift,and accurately place the screws.It has a point-like contact lamina structure to avoid extensive and complete dissection of the posterior structure,and reduce bleeding,operation time,and trauma.Pre-designed screw entry points and directions can reduce the number of fluoroscopy and operation time.Segmental design can avoid discomfort due to changes in anesthesia position.The operation is simple and the accuracy of screw placement is high.