Biomechanical Comparison of Anterior Lumbar Screw-plate Fixation versus Posterior Lumbar Pedicle Screw Fixation

Anterior lumbar interbody fusion （ALiF） followed by posterior pedicle screw fixation （PSF） in a second procedure is mostly used to implement lumbar spine fusion. ALIF followed by an- terior lumbar screw-plate has a lot of advantages, but its biomechanical stability requires confirma- tion. This study evaluated the biomechanical stability of a novel anterior lumbar locked screw-plate （ALLSP） by comparison with posterior lumbar PSF. Twelve fresh human cadaveric lumbar speci- mens （L4-L5） were assigned to four groups： ALIF^PSF group, ALIF＋ALLSP （both fixed） group, ALIF group and an untreated control （both non-fixed） group. The first three groups received implan- tation of a rectangular titanium cage. Tests under axial compression, flexion, extension, lateral bend- ing, or rotation showed that the fixed groups had significantly stronger stability than the non-fixed groups （P=-0.000 for all）. The ALIF＋ALLSP group had significantly greater axial stiffness under ap- plied axial compression and significantly less angular displacement under rotational forces than the ALIF＋PSF group. The angular displacement of the ALIF＋ALLSP group was less under flexion than that of the ALIF＋PSF, and the angular displacement under lateral bending and extension was greater, but these differences were not statistically significant. In summary, the ALLSP conforms to the ante- rior lumbar spine and has good biomechanical stability. It is a reliable choice for enhancing the sta- bility of ALIF.

Normalization strategy of microarray gene expression data

Objective： To discuss strategies and methods of normalization on how to deal with and analyze data for different chips with the combination of statistics, mathematics and bioinformatics in order to find significant difference genes. Methods： With Excel and SPSS software, high or low density chips were analyzed through total intensity normalization （TIN） and locally weighted linear regression normalization （LWLRN）. Results： These methods effectively reduced systemic errors and made data more comparable and reliable. Conclusion： These methods can search the genes of significant difference, although normalization methods are being developed and need to be improved further. Great breakthrough will be obtained in microarray data normalization analysis and transformation with the development of non-linear technology, software and hardware of computer.

Postoperative morbidity adversely impacts oncological prognosis after curative resection for hilar cholangiocarcinoma

BACKGROUND Postoperative morbidity after curative resection for hilar cholangiocarcinoma(HCCA)is common;however,whether it has an impact on oncological prognosis is unknown.AIM To evaluate the influence of postoperative morbidity on tumor recurrence and mortality after curative resection for HCCA.METHODS Patients with recently diagnosed HCCA who had undergone curative resection between January 2010 and December 2017 at The First Affiliated Hospital of Army Medical University in China were enrolled.The independent risk factors for morbidity in the 30 d after surgery were investigated,and links between postoperative morbidity and patient characteristics and outcomes were assessed.Postoperative morbidities were divided into five grades based on the Clavien-Dindo classification,and major morbidities were defined as Clavien-Dindo≥3.Univariate and multivariate Cox regression analyses were used to evaluate the risk factors for recurrence-free survival(RFS)and overall survival(OS).RESULTS Postoperative morbidity occurred in 146 out of 239 patients(61.1%).Multivariate logistic regression revealed that cirrhosis, intraoperative blood loss > 500 mL, diabetes mellitus,and obesity were independent risk factors. Postoperative morbidity was associated with decreasedOS and RFS (OS: 18.0 mo vs 31.0 mo, respectively, P = 0.003;RFS: 16.0 mo vs 26.0 mo, respectively,P = 0.002). Multivariate Cox regression analysis indicated that postoperative morbidity wasindependently associated with decreased OS [hazard ratios (HR): 1.557, 95% confidence interval(CI): 1.119-2.167, P = 0.009] and RFS (HR: 1.535, 95%CI: 1.117-2.108, P = 0.008). Moreover, majormorbidity was independently associated with decreased OS (HR: 2.175;95%CI: 1.470-3.216, P <0.001) and RFS (HR: 2.054;95%CI: 1.400-3.014, P < 0.001) after curative resection for HCCA.CONCLUSIONPostoperative morbidity (especially major morbidity) may be an independent risk factor forunfavorable prognosis in HCCA patients following curative resection.

Online electrophysiological spike discrimination with wavelet-fractal signatures

Objective: To study extracellular multi-neuron activity in the nervous system based on wavelet-fractal technique. Methods: The wavelet transform was employed to decompose the original signal and obtain 4 sub-patterns. The dividing fractal dimensions of these sub-patterns were computed. A knn-classier was used to classify feature vectors. Results: Not all the elements in feature vector DimDC were very powerful for this pattern recognition problem through the empirical study of noise signals. The most effective feature vector was defined as DimDC= (d3:d4) above. Conclusion:Wavelet fractal algorithm has high accuracy and provides a powerful tool for clinical application.

Logistic Regression Analysis of Damp-Heat and Cold Damp Impeding Syndrome of Rheumatoid Arthritis:A Perspective in Chinese Medicine

Objective： To investigate a method for quantitative differential diagnosis of damp-heat and cold-damp impeding syndrome of rheumatoid arthritis （RA） in Chinese medicine （CM）. Methods： Laboratory parameters were collected from 306 patients with RA. The clinical symptoms and laboratory parameters were compared between patients with these two syndromes （158 with RA of damp-heat impeding syndrome, and 148 with RA of cold-damp impeding syndrome）, and a regression equation was established to facilitate discrimination of the two RA syndromes. Results： There were significant differences in disease activity score in 28 joints [DAS28 （4）], erythrocyte sedimentation rate （ESR）, white blood cell count （WBC）, C-reactive protein （CRP）, platelet count （PLT）, albumin （ALB） and globulin （GLB） between the two syndrome of RA （P〈0.05）. Logistic regression analysis showed that the parameters ESR, WBC, CRP, joint pyrexia, joint cold, thirst, sweating, aversion to wind and cold, and cold extremities were statistically useful to discriminate damp-heat from cold-damp impeding syndrome. The regression equation was as follows： P=1/{1＋exp[-（3.0-0.021X1-0.196X2-0.163X3- 1.559X4＋1.504X5-0.927X6-1.039X7＋1.070X8＋1.330X9）]}. The independent variables X1-X9 were ESR, WBC, CRP, hot joint, cold joint, thirst, sweating, aversion to wind and cold, and cold limbs. A P value 〉 0.5 signified cold-damp impeding syndrome, and a P value 〈 0.5 signified damp-heat impeding syndrome. The accuracy was 90.2%. Conclusion： The regression equation may be useful for discriminating damp-heat from cold-damp impeding syndrome of RA.