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 study DNA damages of liver cells in rats exposed to vinyl chloride monomer (VCM), and the expressions of DNA damage repair enzymes including O(6)-methyl guanine-DNA methyl transferase (MGMT), X-ray repair cross-complementing group 1 (XRCC1) and X-ray repair cross-complementing group 3 (XRCC3); and to explore the repair mechanism of DNA damage induced by VCM.

METHODSRats were exposed to VCM by intraperitoneal injection. DNA damages were detected by single cell gel electrophoresis (comet assay). The expressions of DNA damage repair enzymes were measured by immunohistochemical methods.

RESULTSThe percentages of comet cells in low, moderate, and high dose groups (11.75%, 12.38%, and 17.63%, respectively) were greater than that of control (5.67%). The latter two groups were significantly different from that of control (P < 0.05, P < 0.01). The expressions of MGMT and XRCC1 decreased, and XRCC3 increased with the dose of VCM increased. DNA damage was correlated with the expression of XRCC3 (r = 0.438, P = 0.067).

CONCLUSIONVCM can cause DNA damage of liver cells with dose-response relationship. DNA damage repair enzymes take part in the repairing of DNA damage induced by VCM.

Animals ; Carcinogens ; toxicity ; DNA Damage ; drug effects ; DNA Repair ; DNA-Binding Proteins ; genetics ; metabolism ; Dose-Response Relationship, Drug ; Liver ; cytology ; metabolism ; Male ; O(6)-Methylguanine-DNA Methyltransferase ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Vinyl Chloride ; toxicity ; X-ray Repair Cross Complementing Protein 1

OBJECTIVETo study the clinical and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) infection in children.

METHODA total of 37 MRSA strains were isolated from hospitalized patients in Children's Hospital of Fudan University from March 2009 to November 2011. The clinical characteristics were investigated by a cohort study. Furthermore, the mecA, Panton-Valentine leucocidin (PVL) genes were detected by polymerase chain reaction (PCR), and the genotypes of SCCmec were determined by multiplex PCR.

RESULT(1) Among the 37 MRSA isolates, infections with 21 were acquired from hospital (HA-MRSA), and 16 isolates were acquired from community (CA-MRSA). (2) In the study, MRSA frequently caused respiratory tract infection, and most of the strains were isolated from intensive care unit (ICU). (3) CA-MRSA was most frequently associated with skin and soft tissue infections (SSTI), suppurative tonsillitis, even pneumonia and septicemia. HA-MRSA infection was more aggressive, most frequently associated with pneumonia, septicemia, and central nervous system (CNS) infections, such as meningitis. In children with fever caused by HA-MRSA or CA-MRSA infection, HA-MRSA showed a longer duration of fever, for 10.5 days. C-reactive protein (CRP) level caused by HA-MRSA (63.00 mg/L) was higher than CA-MRSA (9.50 mg/L) , and there were statistically significant differences between the groups (t = 2.5670, P < 0.05). However, there were no statistically significant differences between the groups in white blood cell count (WBC) or procalcitonin (PCT) level. (4) Among 37 MRSA isolates, the whole isolates were mecA gene positive (100%). SCCmec genotyping results showed that the most frequent SCCmec types were type III, 17 isolates, the others including type IV 8 isolates, type II1 isolates, nontypable 11 isolates, type I and type V were not found in this group. Therein, among 21 HA-MRSA isolates, SCCmec III was the most common, 15 isolates, type IV 1 isolates, nontypable 5 isolates; among 16 CA-MRSA isolates, SCCmec type IV was the most common, 7 isolates, type III 2 isolates, type II 1 isolate, nontypable 6 isolates. (5) Among the 37 MRSA isolates, 28 were PVL gene positive; and among 21 HA-MRSA isolates, 17 were PVL gene positive; Among 16 CA-MRSA isolates, 11 were PVL gene positive; There were no statistically significant differences between the groups (χ(2) = 0.735, P > 0.05) .

CONCLUSIONCompared with CA-MRSA, HA-MRSA infection was more aggressive, and induced higher C reactive protein; the dominant epidemic strains of CA-MRSA was SCCmec type IV, and HA-MRSA was SCCmec type III; the positive rate of PVL gene was high.

Adolescent ; Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; Bacterial Toxins ; genetics ; Bacterial Typing Techniques ; Child ; Child, Preschool ; China ; epidemiology ; Cohort Studies ; Community-Acquired Infections ; epidemiology ; microbiology ; Cross Infection ; epidemiology ; microbiology ; DNA, Bacterial ; genetics ; Female ; Genotype ; Humans ; Infant ; Infant, Newborn ; Male ; Methicillin ; pharmacology ; Methicillin Resistance ; genetics ; Methicillin-Resistant Staphylococcus aureus ; classification ; genetics ; isolation & purification ; Penicillin-Binding Proteins ; Staphylococcal Infections ; epidemiology ; microbiology

OBJECTIVETo investigate the treatment for traumatic intervertebrae disk herniation in cervical thoracic junction.

METHODSFrom 2003 to 2008, there were 10 patients with trautimatic intervertebral disk herniation in cervical thoracic junction, which included 6 males and 4 females, aged from 23 to 66 years (means 41.5 years). All of them were performed through the transforminal approach combined with internal fixation. After operation all patient underwent hyperbaric oxygen treatment. The function of spine was evaluated by JOA score system.

RESULTSAll patients were followed up for 8 to 16 months(means 13 months). All patients got recovery of spine function to some extent except one case with complete spine damaged. The JOA scores was improved from (8 +/- 3) before operation to (15 +/- 2) after operation.

CONCLUSIONEarly and effective treatment by transforminal operation could be helpful for the recovery of spine function.

Adult ; Aged ; Cervical Vertebrae ; injuries ; surgery ; Female ; Fracture Fixation, Internal ; methods ; Humans ; Intervertebral Disc Displacement ; surgery ; Male ; Middle Aged ; Thoracic Vertebrae ; injuries ; surgery