[Biomechanical study of different kinds of internal fixation for the typeâ Hangman fracture, type â ¡ odontoid fracture and the C(2/3) disc injury: a finite-element analysis].

Objectives: To analyze the biomechanical stability of four kinds of internal fixation for the type Ⅰ Hangman fracture, type Ⅱ odontoid fracture and the C(2/3) disc injury by finite element (FE) analysis. Methods: Thin-section spiral computed tomography (0.5 mm) was performed on C(1) to C(3) region of cervical vertebra in healthy male volunteers.A three-dimensional hexahedral FE model of upper cervical spine was established by software (Mimics, GEOMAGICS, Pro/E and Ansys). Then the weakening of the strength of grid was performed to simulate the FE model of the type Ⅰ Hangman fracture, type Ⅱ odontoid fracture and the C(2/3) disc injury (FE/Fracture), the four internal fixation models: anterior cervical plate+ odontoid screw+ cage (FE/ACP+ OS+ cage), affixing rods from pedicle screws in C(2) to lateral mass screws in C(3)+ odontoid screw + cage (FE/C(2)PS+ C(3)LMS+ OS+ cage), affixing rods from pedicle screws in C(1) to pedicle screws in C(2) and lateral mass screws in C(3) (FE/C(1)PS+ C(2)PS+ C(3)LMS), anterior odontoid screw plate fixation system (FE/AOSP) were simulated on the FE/Fracture model.Flexion, extension, lateral bending and axial rotation were imposed on the FE/Intact, FE/Fracture and the four fixation models respectively. Results: The intact model of upper cervical spine (C(1)-C(3)) was established successfully, consisting of 259 641 nodes and 403 674 units.There was no significant difference among the FE/ACP+ OS+ cage, the FE/ C(2)PS+ C(3)LMS+ OS+ cage and the FE/AOSP of ROMC(1/2).During flexion, extension, left axial rotation and right axial rotation of ROMC(2)-C(3), the FE/AOSP decreased 70.7%, 74.4%, 38.9%, 41.1% respectively compared with the FE/C(1)PS+ C(2)PS+ C(3)LMS.The ROMC(2)-C(3) during flexion, extension, left lateral bending, right lateral bending, left axial rotation and right axial rotation in the FE/AOSP decreased for 82.2%, 82.8%, 73.2%, 64.8%, 72.2%, 81.5% respectively when compared with those in FE/ACP+ OS+ cage.The ROMC(2)-C(3) during flexion, extension, left lateral bending, right lateral bending, left axial rotation and right axial rotation in the FE/AOSP decreased 88.2%, 81.2%, 47.6%, 41.2%, 38.9%, 39.0% respectively when compared with those in FE/C(2)PS+ C(3)LMS+ OS+ cage.The stress concentrated on the connection between plate and screw in the FE/ACP+ OS+ cage, the FE/C(2)PS+ C(3)LMS+ OS+ cage and the FE/C(1)PS+ C(2)PS+ C(3)LMS, while it distributed evenly in the FE/AOSP. Conclusion: Anterior odontoid screw plate fixation system can be used to treat the type Ⅰ Hangman fracture, type Ⅱ odontoid fracture, and the C(2/3) disc injury and can reserve the function of atlanto-axial joint.

IGFBP2 induces SPRY1 expression via NF-κB signaling pathway in glioblastoma multiforme (GBM).

OBJECTIVE: Gliomas are accompanied with high mortality owning to their invasive peculiarity and vulnerability to drug resistance. miR-21 is a vital oncogenic miRNA that regulates drug resistance of tumor cells. This study aims to elucidate the function of miR-21 in human glioma cells resistant to carmustine (BCNU) and to demonstrate the underlying molecular mechanism. MATERIALS AND METHODS: BCNU-sensitive cells (SWOZ2 cells) were transfected with miR-21 agomir and negative control, and BCNU-resistance cells (SWOZ2-BCNU cells) were transfected with miR-21 antagomir and negative control. The Real-time fluorescence quantitative PCR was used to detect and compare the levels of miR-21expression between SWOZ2-BCNU and SWOZ2 cells. The drug sensitivity of these cells to BCNU was determined by Cell Counting Kit-8 (CCK-8) assay. The protein expression of Spry2 was detected by Western blotting. RESULTS: The expression level of miR-21 was remarkably higher in SWOZ2-BCNU cells than that in SWOZ2 cells. The half-maximal inhibitory concentration (IC50) of BCNU was obviously higher for SWOZ2-BCNU cells than that for SWOZ2 cells. Besides, we found that aberrant expression of miR-21 in SWOZ2-BCNU cells is responsible for glioma BCNU-resistance. Consistently, Spry2 protein levels were significantly reduced in SWOZ2-BCNU as well as in miR-21 agomir-transfected cells, inversely correlated to miR-21 expression. The results of si-Spry2 co-transfection suggested that the effect of miR-21 on glioma BCNU-resistance is mediated through Spry2. CONCLUSIONS: miR-21 enhances the resistance of human glioma cells to BCNU by decreasing the expression of Spry2 protein. Thus, Spry2 may be a novel therapeutic target for treating glioma BCNU-resistance.

[Association between hematocrit and risk of incident hypertension: a cohort study].

Objective: To explore the association between hematocrit level and risk of incident hypertension. Method: Subjects who participated at least two times routine health check-up in Health Management Center of Shandong Province Hospital between January 2005 and January 2010 were eligible for inclusion. After excluding participants with known hypertension and other related diseases, a prospective cohort with 20 606 subjects (female: 8 218, male: 12 388) was established. Cox-proportional hazard model was used to assess the association between hematocrit and the development of hypertension for female and male respectively. Results: During the 51 352 person-years of follow-up, newly developed hypertension was confirmed in 3 695 cases. For female, the age-adjusted hazard ratios (95%CI) for incident hypertension were 1.00 (reference), 1.06(0.86-1.29), 1.37(1.14-1.65), 1.60(1.34-1.92), respectively (P for trend<0.000 1) through the 3 quartiles of hematocrit levels.After adjusting multiple factors (age, smoking, drinking habit, physical activity, body mass index(BMI), systolic blood pressure, fasting blood glucose, serum creatinine, high-density lipoprotein, gamma-glutamyl transferase, white blood count), the hazard ratios (95%CI) were 1.00(reference), 1.05(0.85-1.29), 1.25(1.03-1.51), and 1.22(1.00-1.48), respectively (P for trend=0.016 9). For male, the hazard ratio (the highest vs. the lowest hematocrit level) after adjusting age or age and life style factors (smoking, drinking habit, physical activity) was 1.23 (1.11-1.37), 1.21(1.09-1.35), respectively. Other analyses of relationship hematocrit with incident hypertension were not statistically significant in male. Conclusions: Higher hematocrit level is associated with higher risk of incident hypertension, especially in female.

[A biomechanical evaluation of odontoid screw plate fixation system].

OBJECTIVE: To evaluate the biomechanical stability of anterior odontoid screw plate (AOSP). METHODS: Eight fresh-frozen cadaveric cervical spine specimens were subjected to stepwise destabilization of the C1-C3 complex, simulating a type Ⅰ Hangman fracture, type Ⅱ odontoid fracture, and the C2-3 disc injury. Intact specimens, fractured specimens, and fractured specimens with posterior, anterior fixation techniques were divided into six groups: control group (intact), injury group of type Ⅱ odontoid fracture and type Ⅰ Hangman fracture combined with C2-3 disk injury, after anterior cervical plate+ odontoid screw+ cage (ACP+ OS+ cage) group, after anterior odontoid screw plate (AOSP) fixation system group, after affixing rods from pedicle screws in C2 to lateral mass screws in C3+ odontoid screw (C2PS+ C3LMS+ OS) group, after affixing rods from pedicle screws in C1 to pedicle screws in C2 and lateral mass screws in C3 (C1PS+ C2PS+ C3LMS) group. The range of motion (ROM) and neutral zone of C1-C2 and C2-C3 segment was tested. RESULTS: There was statistically significant difference between the C1PS+ C2PS+ C3LMS fixation group and the AOSP fixation group of ROMC1-C2(P<0.05). During all loading modes, AOSP+ Bone graft fixation significantly outperformed the ACP+ OS+ cage fixation in limiting ROMC2-C3. During flexion and extension, AOSP fixation significantly outperformed the C1PS+ C2PS+ C3LMS fixation and C2PS+ C3LMS+ OS fixation in limiting ROMC2-C3. CONCLUSION: The AOSP fixation system has excellent biomechanical performance when dealing with type Ⅰ Hangman fracture, type Ⅱ odontoid fracture, and the C2-3 disc injury, and appear to be a safe and effective technique for dealing with the combined injury.

High-intensity laser-induced electron acceleration in vacuum.

In this paper, an approximate pulsed-laser-beam solution of Maxwell's equation in vacuum is derived. Then with the numerical simulation method, electron acceleration induced by high-intensity [Q(0)=eE(0)/(m(e)omega c)=3] lasers is discussed in connection with the recent experiment of Malka et al. It is found that the maximum energy gain and the relationship between the final energy and the scattering angle can be well reproduced, but the polarization effect of electron-laser interactions is not very prominent. These results show that the ponderomotive potential model is still applicable, which means that the stimulated Compton scattering is the main fundamental mechanism responsible for the electron acceleration at this laser intensity.

[Chronic process with Non-A and Non-B hepatitis disseminated from the intestine (appended 500 cases followed up for two years)].

At present Non-A and Non-B hepatitis disseminated from the intestine in the world is believed to have a better prognosis and has no chronicity. From 1980-1986, this hepatitis has occurred in the south of Xinjiang. It was sporadic (1980-1985) and there was an outbreak (1986). Our study indicated that the results from 500 cases followed up for two years were different from the literature reported. 1. Patients with hepatomegaly were 11.2% at 7th months, 12.8% at 19th months and 45.3% at 28th months. At the same time there were 3 cases of splenomegaly and spider in each of the 19th month and 28th month. 2. Liver function test showed that gamma-GTP, BSP and gamma-globulins rose in different degrees among the 3-7 month cases. Reexamined at 19th months, 3.6% cases of both ZTT and SGPT were high. General proteins of 8% patients dropped. In 42% of the patients the globulins rose and the album in dropped. 3. Biopsy of the liver after 28th months demonstrated that it was in agreement with the pathologic changes found in chronic lobule hepatitis of CPH under the light microscope and electron microscope.