18 research outputs found

    The reliability and diagnostic value of radiographic criteria in sagittal spine deformities: Comparison of the vertebral wedge ratio to the segmental Cobb angle

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    STUDY DESIGN. A prospective, radiographic cohort study. OBJECTIVES. This study assessed the radiographic reliability and diagnostic value of the vertebral wedge ratio (WR) to the more segmental Cobb angle (CA) regarding sagittal spine deformities. SUMMARY OF BACKGROUND DATA. The use of the CA has been used to assist in the radiographic diagnosis of various sagittal spine deformities. However, the reliability and diagnostic aptitude of the CA remains speculative and may not be as receptive to individual variations of vertebral integrity in sagittal spine deformities. METHODS. Sixty patients (age range, 8-21 years) who were diagnosed with Scheuermann's kyphosis (Group 1; n = 16), with postural roundback (Group 2; n = 23), or who were regarded normal (Group 3; n = 21) were radiographically evaluated to assess the reliability and diagnostic potential of the vertebral WR (apex of the curve and 2 adjacent vertebrae) and segmental CA. Radiographic assessment was conducted by 3 independent blinded observers on 3 separate occasions. RESULTS. Very strong intraobserver (WR a = 0.85-0.99; CA a = 0.97-0.99) and interobserver (WR a = 0.79-0.89; CA a = 0.95) reliabilities were noted. A greater degree of WR reliability was noted in Group 1, whereas CA reliability remained consistent in all Groups. A statistically significant difference was found between all Groups in relation to vertebral WR and segmental CA (P < 0.05). Based on relative risk ratio analyses, an apex wedge ratio of ≀0.80 and/or a segmental Cobb angle of ≄20° is highly and significantly associated with Scheuermann's kyphosis. CONCLUSION. The segmental CA exhibited a higher degree of reliability than the vertebral WR. The apex vertebral WR exhibited the greatest amount of wedging in the Scheuermann's patients; whereas in the other groups it remained largely consistent with the adjacent vertebral WRs. An apex vertebral WR ≀0.80 and/or a segmental CA of ≄20° are highly associated with the clinical diagnosis of Scheuermann's kyphosis. If the segmental CA cannot be ascertained, the apex vertebral WR is a relatively strong reliable alternative, primarily with regards to Scheuermann's kyphosis. In addition, the type of deformity may potentially dictate the ideal measuring method. © 2007 Lippincott Williams & Wilkins, Inc.link_to_subscribed_fulltex

    Intraocular Lens Unfurling Time Exponentially Decays with Increased Solution Temperature

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    Erick E Rocher,1 Rishima Mukherjee,1 James Pitingolo,1 Eli Levenshus,1 Gwyneth Alexander,1 Minyoung Park,1 Rupsa Acharya,1 Sarah Khan,1 Jordan Shuff,1 Andres Aguirre,1 Shababa Matin,2 Keith Walter,3 Allen O Eghrari4 1Center for Bioengineering Innovation and Design, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; 2Rice 360 Institute for Global Health Technologies, Rice University, Houston, TX, USA; 3Department of Ophthalmology, Wake Forest Baptist Health, Winston-Salem, NC, USA; 4Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USACorrespondence: Allen O Eghrari, Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, 400 N Broadway, Smith 5013, Baltimore, MD, 21231, USA, Email [email protected]: Intraocular lens (IOL) unfurling can be a rate-limiting step in cataract surgery, limiting operative efficiency. Furthermore, inefficient unfurling has important implications for clinical outcomes. We examine the effects of solution temperature on IOL unfurling time using three in vitro models of the ocular environment.Methods: IOLs were injected into a 6-well plate filled with balanced salt solution (BSS), dispersive ophthalmic viscoelastic device (OVD), or cohesive OVD. Experiments were also performed in a plastic eye filled with dispersive or cohesive OVD. IOL unfurling time was recorded against the temperature of the respective solution.Results: IOL unfurling time decayed exponentially as solution temperature increased in all experiments, including the BSS-filled 6-well plate, the OVD-filled 6-well plate, and the OVD-filled plastic eye. IOLs failed to unfurl within 10 min at 10°C, below the glass transition temperature of the tested IOLs. Increasing solution temperature from 20°C to 30°C decreases IOL unfurling by greater than 2 min. Further heating to 40°C did not significantly decrease IOL unfurling time.Conclusion: Increased solution temperature rapidly decreases IOL unfurling time in vitro. IOLs do not unfurl within a clinically acceptable timeframe at or below their glass transition temperature. Increased BSS and/or OVD temperature may be a potential method to decrease IOL unfurling time in cataract surgery. However, future research is needed to elucidate potential consequences of warmed BSS and/or OVD on post-operative outcomes. This study demonstrates the potential for temperature regulation to decrease cataract surgery operative time and provides preliminary evidence to justify future clinical validation of this relationship.Plain Language Summary: During cataract surgery, a prosthetic intraocular lens (IOL) is inserted into the eye once the clouded lens is removed. The IOL must then unfurl before the procedure can proceed. When IOLs fail to unfurl or unfurl slowly, this can delay the operation and may even cause post-operative complications. Thus, we studied the effect temperature may have on IOL unfurling time to optimize this segment of the operation.We injected IOLs into solutions of saline (balanced salt solution) or ophthalmic viscoelastic device (OVD), two fluids injected into the eye during surgery. In both a well plate and a plastic eye, we found that increasing the temperature of the solution significantly affected IOL unfurling time. Specifically, heating the solution from refrigeration to room temperature decreased unfurling time from over 10 min to less than four. Heating to physiological temperature further decreased unfurling time to less than a minute.Our results show promise for potentially utilizing heated BSS and/or OVD to accelerate IOL unfurling and decrease cataract surgery operative time.Keywords: cataract surgery, balanced salt solution, ophthalmic viscoelastic devic

    Identifying vulnerable brain networks in mouse models of genetic risk factors for late onset Alzheimer's disease

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    The major genetic risk for late onset Alzheimer’s disease has been associated with the presence of APOE4 alleles. However, the impact of different APOE alleles on the brain aging trajectory, and how they interact with the brain local environment in a sex specific manner is not entirely clear. We sought to identify vulnerable brain circuits in novel mouse models with homozygous targeted replacement of the mouse ApoE gene with either human APOE3 or APOE4 gene alleles. These genes are expressed in mice that also model the human immune response to age and disease-associated challenges by expressing the human NOS2 gene in place of the mouse mNos2 gene. These mice had impaired learning and memory when assessed with the Morris water maze (MWM) and novel object recognition (NOR) tests. Ex vivo MRI-DTI analyses revealed global and local atrophy, and areas of reduced fractional anisotropy (FA). Using tensor network principal component analyses for structural connectomes, we inferred the pairwise connections which best separate APOE4 from APOE3 carriers. These involved primarily interhemispheric connections among regions of olfactory areas, the hippocampus, and the cerebellum. Our results also suggest that pairwise connections may be subdivided and clustered spatially to reveal local changes on a finer scale. These analyses revealed not just genotype, but also sex specific differences. Identifying vulnerable networks may provide targets for interventions, and a means to stratify patients
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