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A novel structural dynamics test method and device were designed to test the biomechanical effects of dynamic axial loading on knee cartilage and meniscus. Firstly, the maximum acceleration signal-to-noise ratio of the experimental device was calculated by applying axial dynamic load to the experimental device under unloaded condition with different force hammers. Then the experimental samples were divided into non-specimen group (no specimen loaded), sham specimen group (loaded with polypropylene samples) and bovine knee joint specimen group (loaded with bovine knee joint samples) for testing. The test results show that the experimental device and method can provide stable axial dynamic load, and the experimental results have good repeatability. The final results confirm that the dynamic characteristics of experimental samples can be distinguished effectively by this device. The experimental method proposed in this study provides a new way to further study the biomechanical mechanism of knee joint structural response under axial dynamic load.
Subject(s)
Animals , Cattle , Biomechanical Phenomena , Knee Joint/physiology , Meniscus , Mechanical Phenomena , Weight-BearingABSTRACT
Objective:To investigate the independent predictors of the long-term clinical outcomes in patients with branch atheromatous disease (BAD) in lenticulostriate artery (LSA) territory.Methods:Patients with LSA-BAD admitted to the Department of Neurology, Zhongnan Hospital of Wuhan University from January 1, 2016 to June 1, 2019 were enrolled retrospectively. Their demography, vascular risk factor, and baseline clinical data were collected. The National Institutes of Health Stroke Scale (NIHSS) was used to evaluate the severity of stroke. The clinical outcomes were evaluated by the modified Rankin Scale at 6 months. 0-2 was defined as good outcome, and >2 was defined as poor outcome. Multivariate logistic regression analysis was used to determine the independent influencing factors of clinical outcomes in patients with LSA-BAD. Results:A total of 81 patients with LSA-BAD were enrolled. Their age 59.20±11.75 years (range, 39-81 years), 53 were male (65.4%), and median baseline NIHSS score was 1.0 (interquartile range, 0-4.0). Forty-one patients (50.6%) received intravenous thrombolysis. At 6-month follow-up after the onset, 63 patients (77.8%) had a good outcome, and 18 (22.2%) had a poor outcome. The baseline NIHSS score of the poor outcome group was significantly higher than that of the good outcome group (6.5 [0-9.0] vs. 1.0 [0-3.0]; Z=2.395, P=0.017), while the proportion of mild stroke (61.6% vs. 98.4%; χ2=17.595, P<0.001) and patients receiving intravenous thrombolysis (38.9% vs. 54.0%; χ2=4.450, P=0.035) were significantly lower than those of the good outcome group. Multivariate logistic regression analysis showed that after adjusting for other confounding factors, venous thrombolysis was independently correlated with the good outcome (odds ratio 0.099, 95% confidence interval 0.011-0.924; P=0.042), while the high baseline NIHSS score was independently associated with the poor outcome (odds ratio 1.736, 95% confidence interval 1.262-2.388; P=0.001). Conclusion:Intravenous thrombolysis is helpful to improve the outcomes of patients with LSA-BAD, and a higher baseline NIHSS score is an independent predictor of the poor outcome.
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?AIM:To compare the coherence and difference on the fundus examination made with two kinds of optical coherence tomography ( OCT): Angio-OCT and fourier domain-optical coherence tomography ( FD-OCT) .?METHODS:Using Angio-OCT and FD-OCT to measure the retinal nerve fiber layer ( RNFL ) thickness, optic parameters, and ganglion cell complexes ( GCC ) thickness from 20 subjects respectively.The coherence was tested with Pearson's correlation coefficient, the difference was tested with paired Student t testing.?RESULTS:The total correlation of the RNFL thickness, optic parameters, GCC thickness made with two kinds of OCT was between 0.7-0.8;the RNFL thickness, optic disk area etc.made with the Angio-OCT were lower than those made with FD-OCT except for the GCC thickness.?CONCLUSION: The results made with two kinds of OCT from the same subject has certain coherence, but cannot be compared directly.
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<p><b>BACKGROUND</b>In vivo quantification of choroidal neovascularization (CNV) based on noninvasive optical coherence tomography (OCT) examination and in vitro choroidal flatmount immunohistochemistry stained of CNV currently were used to evaluate the process and severity of age-related macular degeneration (AMD) both in human and animal studies. This study aimed to investigate the correlation between these two methods in murine CNV models induced by subretinal injection.</p><p><b>METHODS</b>CNV was developed in 20 C57BL6/j mice by subretinal injection of adeno-associated viral delivery of a short hairpin RNA targeting sFLT-1 (AAV.shRNA.sFLT-1), as reported previously. After 4 weeks, CNV was imaged by OCT and fluorescence angiography. The scaling factors for each dimension, x, y, and z (μm/pixel) were recorded, and the corneal curvature standard was adjusted from human (7.7) to mice (1.4). The volume of each OCT image stack was calculated and then normalized by multiplying the number of voxels by the scaling factors for each dimension in Seg3D software (University of Utah Scientific Computing and Imaging Institute, available at http://www.sci.utah.edu/cibc-software/seg3d.html). Eighteen mice were prepared for choroidal flatmounts and stained by CD31. The CNV volumes were calculated using scanning laser confocal microscopy after immunohistochemistry staining. Two mice were stained by Hematoxylin and Eosin for observing the CNV morphology.</p><p><b>RESULTS</b>The CNV volume calculated using OCT was, on average, 2.6 times larger than the volume calculated using the laser confocal microscopy. The correlation statistical analysis showed OCT measuring of CNV correlated significantly with the in vitro method (R 2 =0.448, P = 0.001, n = 18). The correlation coefficient for CNV quantification using OCT and confocal microscopy was 0.693 (n = 18, P = 0.001).</p><p><b>CONCLUSIONS</b>There is a fair linear correlation on CNV volumes between in vivo and in vitro methods in CNV models induced by subretinal injection. The result might provide a useful evaluation of CNV both for the studies using CNV models induced by subretinal injection and human AMD studies.</p>
Subject(s)
Animals , Humans , Mice , Choroidal Neovascularization , Pathology , Disease Models, Animal , Fluorescein Angiography , Mice, Inbred C57BL , Tomography, Optical CoherenceABSTRACT
Objective Cataract surgery is also considered as a type of refractive surgery , but there is few research on the change of preoperative and postoperative ocular biometry measurements .The aim of the study was to compare the A-scan ultrasound biom-etry measurements before and after phacoemulsification with intraocular lens implantation , followed by the analysis on its clinical signifi-cance . Methods Dynamic observation was conducted in 188 eyes of 155 cataract patients who received cataract operation from January 2011 to January 2013 in the department of ophthalmology in Nanjing Gernal Hospital .Measurements were made before surgery and 14 days after surgery by Ultrascan Digital 2000 contact ultraound A-scan (Alcon), including anterior chamber depth (ACD), vitreous cham-ber depth ( V) and axial length ( AL) .Simultaneously , a prospective comparison of measurements was made by A-scan ultrasound in sit-ting and decubitus position .Measurements were also conducted in preoperative and postoperative visual acuity and intraocular pressure of the patients. Results visual acuity and intraocular pressure: The difference between preoperative and postoperative visual acuity [(0.17 ±0.19) vs (0.61 ±0.27)] and intraocular pressure [(15.09 ±8.50) mmHg vs (12.99 ±4.44) mmHg] was of statistical sig-nificance ( P0.05).V:The difference between peroperative and postoperative Vs was of significant difference (P<0.05).No significant difference existed between Vs in sitting and decubitus position before the operation [(16.568 ±2.406) mm vs (16.524 ±5.544) mm,with intraocular lens implantation can get better operation result. In addition, different measuring positions have no influence on A-scan ultrasound measurements except the postoperative vitreous cavity depth .