Double pelvic osteotomy for the treatment of hip dysplasia in dogs

Title from PDF of title page (University of Missouri--Columbia, viewed on May 23, 2012).The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Thesis advisor: Dr. Tony MannIncludes bibliographical references.Canine hip dysplasia (CHD) is the most common developmental orthopedic disease of dogs. Triple pelvic osteotomy (TPO) is a surgery that can be performed at 5 months of age, prior to the development of osteoarthritis. Complication rates of 33-50% have been reported for TPO and have spurned interest in a newer technique, double pelvic osteotomy (DPO). The purpose of this thesis is to review the veterinary literature about CHD, surgical treatment options for CHD, and pelvic osteotomy in particular, and to describe two studies, an in vitro study and a retrospective clinical study comparing complication rates of TPO and DPO We conducted an anatomic study of the effects of DPO on the anatomy of the juvenile canine pelvis. Axial rotation of the acetabulum was performed by DPO of 20o, 25o, and 30o and evaluated with computed tomography in an effort to evaluate which plate size most closely resembled a 20o TPO as previously recommended. The data from this study suggest that a 25o DPO results in the most similar acetabular ventroversion compared with the 20o TPO as indicated by a high concordance correlation (0.902). It was also found that most of the ventroversion with DPO comes at the level of the pubic symphysis. A retrospective clinical study of TPO and DPO was conducted to compare complication rates between the two techniques at the University of Missouri between January 1, 2006 and May 1, 2011. Minor complication rates were similar between the TPO and DPO (46.6 and 42.9%, respectively). However, two major complications (13.3% of cases) occurred with TPO and none occurred with DPO. There were no catastrophic complications. Based on this retrospective study, both the incidence and severity of complications is lower for DPO than TPO

TLR9 polymorphism correlates with immune activation, CD4 decline and plasma IP10 levels in HIV patients

Abstract Background The mechanism behind HIV mediated immune activation remains debated, although the role of virus replication in this process is increasingly evident. Toll like Receptor 9 (TLR9) has been implicated in HIV mediated immune activation via sensing of viral CpG DNA. Polymorphisms in the TLR9 gene and promoter region including TLR9 1635A/G and 1486C/T have been found to be associated with multiple infectious diseases and cancers. Methods In the current study, we looked at the correlation of TLR9 polymorphisms 1635A/G and 1486C/T with key hallmarks of HIV disease in a cohort of 50 HIV infected patients. We analyzed CD4 counts, T cell immune activation characterized by upregulation of CD38 and HLA-DR and upregulation of plasma biomarkers of inflammation like LPS, sCD14, IL-6 and IP10 in the HIV patient cohort and compared it to healthy controls. Results We found that TLR9 1635AA genotype was associated with lower CD4 counts and significantly higher immune activation in both CD4+ and CD8+ T cells. Analysis of HIV associated plasma biomarkers including LPS, sCD14, IL-6 and IP10 revealed a strong correlation between IP10 and immune activation. Interestingly, IP10 levels were also found to be higher in HIV patients with the 1635AA genotype. Furthermore, the TLR9 1486C/T polymorphism that is in linkage disequilibrium with 1635A/G was weakly associated with lower CD4 counts, higher CD8 immune activation and higher IP10 levels. Conclusions As TLR9 stimulation is known to induce IP10 production by dendritic cells, our findings provide new insights into HIV mediated immune activation and CD4 loss. TLR9 stimulation by viral CpG DNA may be important to HIV immunopathogenesis and the TLR9 polymorphisms 1635A/G and 1486C/T may be associated with disease progression

TiO2 anatase with a bandgap in the visible region.

TiO2 anatase plays a central role in energy and environmental research. A major bottleneck toward developing artificial photosynthesis with TiO2 is that it only absorbs ultraviolet light, owing to its large bandgap of 3.2 eV. If one could reduce the bandgap of anatase to the visible region, TiO2-based photocatalysis could become a competitive clean energy source. Here, using scanning tunneling microscopy and spectroscopy in conjunction with density functional theory calculations, we report the discovery of a highly reactive titanium-terminated anatase surface with a reduced bandgap of less than 2 eV, stretching into the red portion of the solar spectrum. By tuning the surface preparation conditions, we can reversibly switch between the standard anatase surface and the newly discovered low bandgap surface phase. The identification of a TiO2 anatase surface phase with a bandgap in the visible and high chemical reactivity has important implications for solar energy conversion, photocatalysis, and artificial photosynthesis

Direct observation of high velocity current induced domain wall motion

We study fast vortex wall propagation in Permalloy wires induced by 3 ns short current pulses with sub 100 ps rise time using high resolution magnetic imaging at zero field.We find a constant domain wall displacement after each current pulse as well as current induced domain wall structure changes, even at these very short timescales. The domain wall velocities are found to be above 100 m/s and independent of the domain wall spin structure. Comparison to experiments with longer pulses points to the pulse shape as the origin of the high velocities

Pelvic modelling and the comparison between plate position for double pelvic osteotomy using artificial cancellous bone and finite element analysis

Background: Finite element analysis was used to compare fixation methods for double pelvic osteotomy (DPO). Using 3D scanning a stereolithography (stl) image was produced of a canine pelvis and this was subsequently refined in computer aided design (CAD). Using the CAD files, the images were imported in MSC Marc software to produce a working finite element (FE) model with 3 dimensional tetrahedral elements with linear shaped functions. The dimensions of a precontoured pelvic osteotomy plate with eight screws and a twisted seven screw straight plate were used to build the 2 fixations implants for the FE models. An equivalent load of 300 N was applied progressively on all FE models in order to facilitate its convergence. The load was applied in a distributed manner on the femur-hip joint contact area in order to simulate the actual behavior of the joint. The aim of the present study was to analyze the difference in stiffness and behavior under loading between a lateral vs ventral plate fixation, with unlocked screws and different gap scenarios, for stabilization of a pelvic osteotomy using finite element analysis. Results: From both configurations the maximum displacement of the ventral plate with 7 screws without gap had a value of 1.988 mm, while in the DPO plate had a maximum displacement of 2.191 mm. The load applied for each of the different configurations studied when a gap of 1° was considered and also when a condition of no gap was considered. The ventral plate was stiffer than the lateral plate when a gap was not present. When the gap was closed in the ventral plate, the stiffness increased until a point that remained constant. Conclusions: Ventral plate fixation can be as or more stiff as lateral plate fixation and provides flexible fixation. This behavior should reduce screw loosening. Using ventral plate fixation is recommended to reduce screw loosening or failure. © 2018 The Author(s)