Finite Element Analysis of the Equine Distal Limb Transfixation Cast

Lescun, Timothy B. Ph.D., Purdue University, December 2015. Finite Element Analysis of the Equine Distal Limb Transfixation Cast. Major Professors: Gert Breur and Eric Nauman

Corneal Biomechanics After Intrastromal Ring Surgery: Optomechanical In Silico Assessment

Purpose: To provide a biomechanical framework to better understand the postsurgical optomechanical behavior of the cornea after ring implantation. Methods: Calibrated in silico models were used to determine the corneal shape and stresses after ring implantation. After mechanical simulations, geometric ray-tracing was used to determine the change in spherical equivalent. The effect of the surgical procedure, circadian variation of intraocular pressure, or the biomechanical weakening introduced by keratoconus (KC) were evaluated for each intrastromal ring. Results: Models predicted the postsurgical optomechanical response of the cornea at a population level. The localized mechanical effect of the additional intrastromal volume introduced by the implants (size and diameter) drives the postsurgical corneal response. However, central corneal stresses did not increase more than 50%, and thus implants did not strengthen the cornea globally. Because of the biomechanical weakening introduced by laser pocketing, continuous implants in a pocket resulted in higher refractive corrections and in the relaxation of the anterior stroma, which could slow down KC progression. Implants can move within the stroma, acting as a dynamic pivot point that modifies corneal kinematics and flattens the corneal center. Changes in stromal mechanical properties did not impact on refraction for normal or pathological corneas. Conclusions: Implants do not stiffen the cornea but create a local bulkening effect that regularizes the corneal shape by modifying corneal kinematics without canceling corneal motion. Translational Relevance: In silico models can help to understand corneal biomechanics, to plan patient-specific interventions, or to create biomechanically driven nomograms

Simulación personalizada de la cirugía de inserción de anillos intraestromales (ICRS). Validación con datos clínicos

El queratocono es una enfermedad ectásica no inflamatoria que provoca la disrrupción de las fibras de colágeno. Una de las técnicas utilizadas para detener la progresión de la enfermedad es la cirguía de inserción de los anillos intraestromales. El objetivo principal es simular dicha intervención quirúrjica utilizando el método de los elementos finitos y comparar los resultados con los obtenidos en la clínica. Se parte de los datos del paciente suministrados por el topógrafo. Esa nube de puntos se transforma en el modelo tridimensional de elementos finitos. Se aplica la metodología descrita en Flecha-Lescún et. al para la simulación numérica de la cirugía, la cual distingue los pasos siguientes: configuración inicial del modelo, cirugía, inflado, inserción de ICRS y cierre. Los resultados obtenidos se transforman en resultados ópticos mediante la aplicación del algoritmo de trazado de rayos. Al introducir los segmentos ICRS, el ápex corneal se desplaza hacia la cámara interna del ojo y se alcanza un estado de relajación en la superficie anterior corneal. Las caracteríticas ópticas corresponidentes a la post-cirugía muestran una reducción de las dioptrías en el centro de la córnea y se estabiliza el queratocono. Además se validan los resultados con los resultados ópticos de la post-cirugía del paciente. La metodología desarrollada puede ser utilizada como ayuda adicional por los cirujanos y para optimizar cuál es la configuración de ICRS (tipo, zona optica de implantación y sección) que maximice la estabilización y minimice las aberraciones.&nbsp

Simulación 3D de implantes de anillos intraestromales para la estabilización del queratocono

Simulación de la operación quirúrgica de implantación de anillos intraestromales (ICRS) para la estabilización del queratocono (enfermadad ecátisa no inflamatoria que provoca la disrupción de las fibras). Las diferentes simulaciones analizadas se realizan sobre un modelo promedio de elementos finitos de córnea, limbo y esclera, siendo estos elementos esféricos. Tanto la córnea como el limbo son considerados materiales hiperélasticos anisótropos; sin embargo la esclera se considera isótropa hiperelástica.Los diferentes experimentos de la inserción de los anillos circulares combinan las siguientes variables: profundidad de implantación (80%, 65% y 50% de espesor corneal), diámetro corneal (5 mm, 6 mm y 7 mm) y diámetro de la sección (0.2 mm, 0.3 mm y 0.5 mm). Los resultados obtenidos se analizan mediante un algoritmo propio de trazado de rayos para obtener diferentes variables ópticas (potencia esférica y cilíndrica de la cornea anterior y posterior así como del frente de onda). Finalmente, mediante un análisis "full factorial" a tres niveles (bajo, medio y alto) de las tres variables determinantes en la inserción de los ISCRS. Se puede conluir, tras el análisis óptico que secciones de diámetro mayor deben implantarse en zonas más alejadas. La variable que más influye en la simulación es el diámetro de la zona de implantación. Además, los anillos actúan como elemento de contención, absorbiendo la mayoría de las tensiones radiales. Esto sugiere que podrían ayudar a estabilizar la progresión del KTC al relajar las tensiones en el tejido.

Global proteomics insights for a novel small compound targeting the non-integrin Laminin Receptor in a macrophage cell model

Introduction: Monocytes and macrophages are the first barrier of the innate immune system, which interact with agents causing osteoarthritis or other conditions, leading to the release of proinflammatory mediators that exacerbate inflammation.Methods: The aim of this study was to investigate the proteomic changes in THP-1 monocytes differentiated to macrophages, pre- or -post small compound treatments and in the presence or absence of a proinflammatory stimulus, Lipopolysaccharide (LPS). This study aimed to discover and isolate small compounds that mimic the interaction between Pigment derived growth factor (PEDF) and its 37/67 kDa Laminin receptor (LR) with potential anti-inflammatory activity.Results: Our results suggested that novel compounds targeting the LR-PEDF interface can be useful for modulating anti-inflammatory effects. Several compounds were selected based on in silico docking at the PEDF/LR interface and examined for their ability to reduce IL-1β expression in a macrophage cell model. Compound C3 showed the highest efficacy in reducing IL-1β expression in the presence of LPS proinflammatory stimulus. Proteomics analysis revealed that C3 treatment altered the global proteomic profile of THP-1 activated macrophages, affecting pathways such as MYC targets, oxidative phosphorylation, and mTORC1 signaling.Discussion: The analysis also highlighted the involvement of key regulators, including RPSA and MYC, and their interactions with other proteins such as ribosome proteins and cell cycle regulators. Furthermore, the downregulated proteome analysis revealed shared and unique pathways affected by the treatments, including processes related to actin cytoskeleton, translation, and the inflammatory response. Protein-protein interaction networks suggested the potential involvement of transcription factors like MYC and the interconnectedness of signaling pathways in mediating such as the effects of the treatments. Overall, these findings provide valuable insights into the potential anti-inflammatory activity and underlying mechanisms of compound C3, emphasizing its relevance for further investigation in the context of inflammatory conditions

Pinos transcorticais e gesso associados à aplicação local de plasma rico em plaquetas no tratamento de fratura do III metatarsiano em potro

In horses less than one year of age fractures of the third metacarpal bone (McIII) or metatarsal bone III (MtIII) are mainly attributed to trauma. Open reduction and internal fixation are the most common treatment method. A Quarter Horse filly with three months of age, which weighed 150kg presented a diaphyseal multifragmentar wedge fracture of right MtIII which was treated with transcortical pins and cast, associated with intralesional application of platelet rich plasma (PRP). After two years of surgery, the animal initiated a training program for racing, and six months later, the patient ran its first official match. The choice of therapeutic methods for treating fractures in horses should be one that provides an earlier repair and minor possibility of complications. Thus, the therapy association which was adopted was considered favorable, since allowed full reestablishment of locomotion of the patient and made possible its return to race.Em potros até um ano de idade, as fraturas do III osso metacarpiano (McIII) ou III metatarsiano (MtIII) são principalmente atribuídas ao trauma. A redução aberta e a imobilização do foco com implantes constituem o tratamento cirúrgico recomendado. Uma potra com três meses de idade e 150kg, da raça Quarto de Milha, que apresentava umafratura diafisária multifragmentar em cunha do MtIII direito foi submetida à osteossíntese através datransfixação externa e gesso, associada com a aplicação intralesional deplasma rico em plaquetas (PRP). Após dois anos do tratamento, o animal iniciou programa de treinamento para corrida e, após seis meses do treinamento, correu o primeiro páreo oficial. A escolha dos métodos terapêuticos para o tratamento de fraturas em equinos deve ser baseada naquela que promova reparação precoce e de melhor qualidade, com menores riscos de complicações. Sendo assim, a associação terapêutica adotada foi considerada favorável, já que possibilitou o completo reestabelecimento da locomoção da paciente, podendo inclusive competir na sua modalidade esportiva.Univ Estadual Paulista Julio Mesquita Filho UNESP, Fac Med Vet &Zootecnia, Dept Cirurgia &Anestesiol Vet, BR-18618970 Botucatu, SP, BrazilMed Vet Autonoma, Brotas, SP, BrazilUniv Estadual Paulista Julio Mesquita Filho UNESP, Fac Med Vet &Zootecnia, Dept Cirurgia &Anestesiol Vet, BR-18618970 Botucatu, SP, Brazi