BACKGROUND:C2 transpedicle screw fixation for Hangman fractures has been paid more attention due to reliability and no loss of physiological function.However,there are lacks of biomechanical evidences for indication treatment because the fixation is single segmental.OBJECTIVE:To investigate the biomechanical stability of C2 transpedicle screw fixation for Hangman fractures.DESIGN,TIME and SEITING:This was a contrast study which was performed at the General Key Laboratory of Biomechanics,First Military Medical University of Chinese PLA from May to August 2004.MATERIALS:AO-universal titanium alloy transpedicle screw of 18 25 mm in length and 3.5 mm in diameter was adopted in this study.Six fresh C1-C4 cervical vetebrae samples were ordiually made into type Ⅰ,ⅡA,and Ⅱ Hangman fracture models.METHODS:After transpedicle screw fixation.Hangman fracture models were measured by non-destroyed style with spinal anterior flexion/posterior extension,left/right lateral curvature,and left/right axial direction.Loading/unlonding circulation was performed three times during each testing.Kinematics indicators were measured on the 3rd circulation.MAIN OUTCOME MEASURES:Spinal motor images at zero load and maximal load were obtained with laser photoscanning(0.1% in precision),and the corresponding systematic software was adopted to calculate 3D range of movement.RESULTS:The relative stability of type Ⅰ Hangman fracture models after C2 transpedicle screw fixation was 100.62%(inflexion),96.91%(posterior extension),99.19%(lateral curvature),and 97.12%(rotation)as compared to control group (P＞0.05).The relative stability of type Ⅱ Hangman fracture models after C2 transpedicle screw fixation was 47.84%(inflexion),21.29%(posterior extension),65.98%(lateral curvature),and 41.69%(rotation)as compared to control group (P＜0.05).CONCLUSION:Biochemical evaluation suggests that type Ⅰ and Ⅱ A Hangman fractures do fit for C2 transpedicle screw fixation,and the fixation may generate well physiological fixation or stability.However,stability of type Ⅱ Hangman fracture is poor,so it is not suitably adopted single transpedicle screw fixation.

BACKGROUND: Decompression-internal fixation is needed in the treatment of atlantoaxial dislocation accompanying with spinal compression caused by cranium-neck junction area malformation and other diseases.Different internal fixation methods are chosen according to different conditions, including anterior atlantoaxial internal fixation, posterior atlantoaxial internal fixation or occipitocervical internal fixation. Transoralpharyngeal atlantoaxial plate internal fixation is a method for atlantoaxial anterior fixation. It is developed recently and used for difficult and complicated atlantoaxial dislocation induced by congenital disease, trauma or rheumatoid arthritis.OBJECTIVE: To probe into the clinical application of transoralpharyngeal atlantoaxial reduction plate system in the atlantoaxial dislocation caused by obsolete odontoid fracture.DESIGN: Single Sample observation SETTING: Department of Orthopaedics, Guangzhou General Hospital of Guangzhou Military Medical University of Chinese PLA PARTICIPANTS: Twelve patients with atlantoaxial dislocation caused by obsolete odontoid fracture were selected in the Department of Orthopaedics, General Hospital of Guangzhou Military Medical University of Chinese PLA from January 2003 to October 2005. Among them, 7 were male and 5 were female, they were aged 47 years on average ranging from 36 to 59 years. The mean injured time was 19 months ranging from 4.5 to 36 months; 6 patients were graded as C degree, 3 as D degree and 3 as E degree in Frank gradation.METHODS: Twelve obsolete odontoid fracture caused by atlantoaxial dislocation underwent transoralpharyngeal anterior decompression. Transoralpharyngeal atlantoaxial reduction plate system was used in reduction and fixation. Autogeneic ilium was implanted into bilateral articulatio atlantoepistrophica.MAIN OUTCOME MEASURES: ① Frank gradation of patients at the 4th week after operation. ② whether the internal fixation is loose or not after operationRESULTS: ①Frank gradation at the 4th week after operation: Among the 6 patients who were primarily graded as C degree, 4 patients improved to be E degree and 2 patients D degree; Three patients who were primarily graded as D degree all improved to be E degree; Patients who were primarily graded as E degree did not changed. ② Except for one patient who suffered dislocation again for loosening of screw caused by tumble, the other patients had firm fixation, ideal fusion and satisfying spinal decompression.CONCLUSION: Transoralpharyngeal atlantoaxial reduction plate system finishes atlantoaxial reduction and fixation once. It avoids conducting posterior fusion fixation operation after anterior decompression. It also avoids fetal injury for spinal cord caused by extreme atlantoaxial unsteadiness in the process of movement and turning over.

OBJECTIVETo investigate the pathogenic factors of human cytomegalovirus (HCMV) infections.

METHODSTotally 36 serum samples were obtained from early pregnant woman and examined with ELISA for anti-HCMV antibody IgG and IgM. After artificial abortion,chorionic villus and decidua were also examined with polymerase chain reaction (PCR) for HCMV-DNA. When the results of PCR were positive, pathological changes of these chorionic villus and decidua were analyzed.

RESULTSThe results showed that only 10 samples were PCR positive while IgG and/or IgM antibody to HCMV was positive. After infection with HCMV, different changes occurred in chorionic villus and decidual trophoblastic cells placental villus were hyperplasic and decidua cells degenerated and necrotized followed by lymphocytes infiltration.

CONCLUSIONThese pathological changes may be one of pathogenic factors of HCMV.

Adult ; Antibodies, Viral ; blood ; Chorionic Villi ; pathology ; virology ; Cytomegalovirus ; genetics ; immunology ; isolation & purification ; Cytomegalovirus Infections ; pathology ; DNA, Viral ; analysis ; Decidua ; pathology ; virology ; Female ; Humans ; Immunoglobulin G ; blood ; Immunoglobulin M ; blood ; Pregnancy ; Pregnancy Complications, Infectious ; pathology ; virology

OBJECTIVETo design a tool for evaluating the sound transmission function of ossicular prosthesis and explore the impacts of ossicular prosthesis bead area and the effects of the mass of ossicular prosthesis on the sound transmission function in mechanical middle ear model.

METHODSTwo latex membranes were used to represent the tympanic membrane and oval window membrane. The ossicular prosthesis was fitted between the artificial tympanic membrane and oval window membrane during the test. Pure tune signals were used to stimulate the vibration of tympanic membrane. The vibration of oval window membrane was recorded by a laser Doppler vibrometer. The ossicular transmission function was evaluated by comparing the vibration velocities of oval window membrane. Two groups of titanium ossicular prosthesis with different head area and mass respectively were fitted into a mechanical middle ear model to evaluate their sound transmission functions.

RESULTSThe feeling threshold curve of mechanical middle ear model (MMEM) was similar to the hearing threshold curve of normal person. The transmission function of the prosthesis with small head area was better than that of prostheses with large head area at frequencies 1500-4000 Hz. The small-massed prostheses functioned better at higher frequencies and the large-massed prostheses functioned better at lower frequencies. But small-massed prostheses functioned better as a whole.

CONCLUSIONSThe MMEM was an idea tool to evaluate the transmission functions of different ossicular prostheses. Both the head area and prosthesis mass had an influence on the transmission function of ossicular prosthesis. So while designing the ossicular prosthesis or performing ossiculoplasty, both the head area and prosthesis mass should he taken into consideration.

Acoustic Impedance Tests ; Acoustics ; Ear, Middle ; anatomy & histology ; Models, Anatomic ; Ossicular Prosthesis ; Prosthesis Design

Objective To explore the relationship between immune and pathogenesis of amyotrophic lateral sclerosis (ALS) in the investigation of neurofilaments phosphorylation and ultrastructure features in spinal cord ventral horn motor neuron injury mediated by immune.Methods Using transmission electron microscope,we studied the uhrastructure features of abnormal accumulations of neurofilaments (NF) in motoneuron of the spinal cord ventral horn,and immunohistochemically investigated neurofilaments phosphorylation.Results Electron microscope found that there was abnormal accumulation of interwoven NFs in motor neuronal perikarya and proximal axons.Immunohistochemical study revealed that the SMI-32 immunoreactive positive neurons (12.00?1.05),compared with control (18.00?1.83),were reduced (P

Objective To evaluate the biomechanical characteristics and the clinical advantage of transoral atlantoaxial reduction plate(TARP)Ⅲ.Methods Design of TARP-Ⅲ was based on TARP-Ⅱ.The screw hole in the axis was moved 1-2 mm upwards and inwards in a plate which turned a vertebral screw into a pedicle screw or an articular process screw.A polyaxial self-lock ring and polyaxial guiding drill were added to the crew hole of the plate.Finally,the withdrawal resist ence force of the three axis screws was tested and TARP-Ⅲ was used in 44 patients with complicated irreducible atlantoaxial dislocation.The axis was fixed with the pedicle screw or the articular process screw.Results The maximum withdrawal resist ence force of the anterior pedicle screw,the articular process screw and the vertebral screw in the axis was(593.1 ± 97.8)N,(469.9 ± 73.3)N and(395.2 ± 75.1)N respectively,with statistical difference between groups among three fixation methods(P ＜ 0.05).All 44 patients were followed up for 5-38 months(average 18 months),which showed complete anatomic reduction in 36 patients and appropriate anatomic reduction in eight,with basic correction of the angles between the brain stem and the spinal cord and sufficient decompression of the spinal cord.The decompression rate of the cervical spinal cord was average 88.2% according to the Yin evaluating method of cervical cord decompression.The improvement rate of spinal cord function was average 76.6% according to Japanese Orthopaedic Association(JOA)score.Conclusion With the design of polyaxial self-lock mechanism,TARP-Ⅲ with the pedicle screw or the articular process screw surpasses TARP-Ⅱ with vertebral screw in aspect of biomechanics.

Objective To develop a double antibody sandwich ELISA assay for quantitative determination of recombinant human interferon α1b.Methods Mouse monoclonal antibodies with different binding site on rIFN-α1b were screened to select optimized candidates as coating and HRP-labeled index antibodies respectively.And a double antibodies sandwich ELISA was assembled; the reliable lower detection limit,specificity,accuracy and reproducibility were evaluated and validated.Results The quantitative sandwich ELISA had a reliable lower detection limit of 10 ng/ml,with a liner detection range 10-100 ng/ml (R2 =0.992),variation coefficient inter-plates is less than 10％.Conclusion The developed sandwich ELISA was a sensitive and specific,accuracy and reproducibility method for quantitative determination of recombinant human interferon αt1b in final product.

OBJECTIVETo investigate biological characteristics of rat bone marrow mesenchymal stem cells (MSC) cultured in vitro and to explore their potential applications.

METHODSMSC were isolated from rat bone marrow by density gradient centrifugation and were induced to differentiation. Flow cytometry was used to characterize their surface antigen expression, cell cycle status and cell growth parameters. Telomerase activity was determined by TRAP-ELISA assay.

RESULTSFusiform MSC became larger and flattener with increasing passages of culture. After the fourth passage, the MSC showed an immunophenotype of CD29 (94.75% +/- 3.68%), CD71 (95.43% +/- 2.23%), and CD90 (98.08% +/- 3.88%). After the seventh passage, MSC with such immunophenotype decreased with CD29: 50.00% +/- 3.35%, CD71: 50.70% +/- 2.43%, and CD90: 48.60% +/- 2.83%. Cells with such immunoprofile completely disappeared after passage 9. Overall, MSC grew faster during the first 5 passages. The number of MSC in S and G(2)/M phases were 38.36% +/- 2.01% and those in G(0)/G(1) phase were 61.64% +/- 2.13% after 3 passages. The cell growth decreased after passage 7. Percentage of MSCs in S and G(2)/M phases was 10.83% +/- 1.63% and that in G(0)/G(1) was 89.17% +/- 1.96% after passage 12, after which the cells failed to further divide. After passage 9, MSCs lost their ability to differentiate to Von Kossa and oil red O positive staining cells. In addition, telomerase activity of MSC also gradually decreased with the prolonged passages, from the original 52.7% +/- 0.78% to no telomerase activity.

CONCLUSIONThe biological and immunophenotypical characteristics of cultured MSC showed obvious alterations with increasing numbers of passage of culture.

Animals ; Antigens, CD ; metabolism ; Bone Marrow Cells ; cytology ; metabolism ; Cell Cycle ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Immunophenotyping ; Integrin beta1 ; metabolism ; Male ; Mesenchymal Stromal Cells ; cytology ; metabolism ; Rats ; Receptors, Transferrin ; metabolism ; Thy-1 Antigens ; metabolism

OBJECTIVETo provide anatomical data for transoral atlantoaxial reduction plate internal fixation.

METHODMicrosurgical dissecting was performed on 10 fresh craniocervical specimens layer by layer according to transoral approach. Stratification of posterior pharyngeal wall, course of vertebral artery, adjacent relationships of atlas and axis and correlative anatomical parameters of internal fixation to atlantoaxial joint were observed.

RESULT(1) Posterior pharyngeal wall consisted of 2 layers and 2 interspace: mucosa, anterior fascia of vertebrae, posterior interspace of pharynx and anterior interspace of vertebrae. (2) The range from anterior rim of foramen magnum to C3 could be exposed by this approach. (3) The distance between the vertebral artery at atlas and midline was (25.2 +/- 2.3) mm and that between the vertebral artery at axis and midline was (18.4 +/- 2.6) mm. (4) The width of atlas and that of axis could be exposed respectively to (39.4 +/- 2.2) mm and (39.0 +/- 2.1) mm. The distance (a) between 2 atlas screw inserting points (center of anterior aspect of C-1 lateral mass) was (31.4 +/- 3.3) mm. The vertical distance (b) between the connecting line of 2 atlas screw inserting points and that of 2 axis screw inserting points (at the central part of the vertebrae which was 3 - 4 mm lateral to the midline of C-2 vertebrae) was (18.7 +/- 2.7) mm. The odds of a/b was 1.5 approximately 1.7.

CONCLUSIONSAnterior atlantoaxial plate internal fixation through transoral approach is suitable and feasible. The design of the plate should be based on the above data.

Atlanto-Occipital Joint ; anatomy & histology ; surgery ; Bone Plates ; Cervical Vertebrae ; anatomy & histology ; surgery ; Equipment Design ; Humans ; Microsurgery ; Oropharynx ; anatomy & histology ; Spinal Fusion ; instrumentation ; methods

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Antigens, CD34 ; metabolism ; Child ; Colonic Neoplasms ; pathology ; Cystadenocarcinoma, Mucinous ; metabolism ; secondary ; Cystadenocarcinoma, Serous ; metabolism ; secondary ; Female ; Humans ; Macrophage Migration-Inhibitory Factors ; metabolism ; Microvessels ; pathology ; Middle Aged ; Neoplasm Recurrence, Local ; Ovarian Neoplasms ; metabolism ; pathology ; secondary ; Stomach Neoplasms ; pathology ; Tumor Suppressor Protein p53 ; metabolism ; Young Adult