Reconstructing an ancient fish: Three-dimensional skeletal restoration of the head of Mawsonia (Sarcopterygii, Actinistia) using CT scan, and an adjusted model for body size estimation in fossil coelacanths.

Mawsonia constitutes one of the most conspicuous fossil coelacanth taxa, due to its unique anatomy and possible maximum body size. It typifies Mesozoic coelacanth morphology, before the putative disappearance of the group in the fossil record. In this work, the three-dimensional cranial anatomy and body size estimations of this genus are re-evaluated from a recently described specimen from Upper Jurassic deposits of Uruguay. The 3D restoration was performed directly on the material based on anatomical information provided by the living coelacanth Latimeria and previous two-dimensional restorations of the head of Mawsonia. The montage was then scanned with computed tomography and virtually adjusted to generate an interactive online resource for future anatomical, taxonomic and biomechanical research. In general terms, the model constitutes a tool to improve both the anatomical knowledge of this genus and its comparison with other coelacanths. It also facilitates the evaluation of possible evolutionary trends and the discussion of particular features with potential palaeobiological implications, such as the anterior position of the eye and the development of the pseudomaxillary fold. Regarding the body size, a previous model for body size estimation based on the gular plate was submitted to OLS, RMA, segmented linear and PGLS regressions (including the evaluation of regression statistics, variance analysis, t-tests and residual analysis). The results point to a power relationship between gular and total lengths showing a better support than a simple linear relationship. The new resulting equations were applied to the studied individual and are provided for future estimates. Although an isometric evolutionary growth cannot be rejected with the available evidence, additional models developed with other bones will be necessary to evaluate possible hidden evolutionary allometric trends in this group of fishes, thus avoiding overestimates.

[Intralesional Injections of 5-Fluorouracil: innovative and effective treatment of Primary Pterygium]. / Inyecciones Intralesionales de 5-Fluorouracilo: tratamiento innovador y efectivo de Pterigión Primario.

OBJECTIVES: To determine the effectiveness of intralesional 5-Fluorouracil (5-FU) in symptomatic relief, astigmatism, and desire for surgery in patients with primary pterygium. METHODS: The experimental study was carried out between January and March 2020 in the Ophthalmology Unit of the Hospital del Salvador, Chile. Fourteen eyes (14 patients) were selected on the surgical waiting list and exposed to fortnightly intralesional injections of 10 mg of 5-FU. An initial evaluation was performed with OSDI for symptomatic measurement, a photographic camera and slit lamp for clinical appearance, and an auto-refractometer for astigmatism, being re-evaluated 60 days later, adding the question of whether they maintained the desire to undergo surgery. The sample was divided into groups A and B depending on whether they received two or one dose of 5-FU, respectively. RESULTS: The average age of the participants was 56.8 ± 11.1 years. Group A presented an initial OSDI of 50 ± 23.8, which, after the intervention, decreased to 21 ± 13.5 (p < 0.001). Group B had an initial OSDI of 47 ± 17.3, decreasing to 22 ± 16.2 (p < 0.005)-statistically significant changes. The degree of astigmatism had no changes. Regarding the physical aspect, there was a reduction in the size of the lesion in 2 of the 14 patients, both in group A. Two patients decided not to undergo surgery after the intervention. CONCLUSIONS: The intralesional injection of 5-FU showed a significant improvement in symptomatic relief without associated complications, generating a therapeutic alternative in patients with primary pterygium without surgical indication.

[Responsible ownership of dogs and human health in neighborhoods of San Carlos de Bariloche, Argentina]. / Tenencia responsable de perros y salud humana en barrios de San Carlos de Bariloche, Argentina.

Human relationship with dogs associates with numerous and varied benefits on human health; however, it also presents significant risks. The goal of this study was to describe demographic parameters and characteristics of dog ownership with possible implications on human health and to evaluate the prevalence of dog bites and traffic accidents due to dogs. Interviews were conducted in the neighborhoods of Nuestras Malvinas and Nahuel Hue in San Carlos de Bariloche. The percentage of homes with at least one dog, the average number of dogs per home, the prevalence of dog bites and traffic accidents due to dogs and the general awareness of the population on dog transmitted zoonoses were estimated. Regarding ownership characteristics, the degree of sterilization, vaccination and parasite control and the percentage of dogs allowed to roam freely in public places were evaluated. A total of 141 interviews were conducted; 87% of the households had at least one dog, with an average of 2.2 dogs. In 26% of the households someone had suffered a traffic accident caused by dogs and in 41% someone had been bitten. Antiparasite treatment was administered to 83% of the dogs in the last 12 months, on average 1.4 times (recommended 6 times), 51% were sterilized, 55% were allowed to roam freely. This study shows a disturbing situation regarding the canine population of the evaluated neighborhoods. The number of dogs allowed to roam freely and the low level of parasite control and sterilization provide suitable conditions for the spread of zoonoses.

Quantifying the forces needed for ureteral stent removal: Initial evaluation of magnetic stent removal devices on benchtop and porcine models.

BACKGROUND: Indwelling ureteral stents are commonly used in pediatric surgeries for kidney stones and urinary tract obstruction, but often require instrumentation or anesthesia for removal. We evaluated the use of novel magnet devices to remove indwelling ureteral stents with a distally attached magnetic bead. Since the forces required for stent removal are unknown, we aimed to characterize and quantify the forces required for stent removal for future prototype testing. METHODS: A custom 3-D urinary tract model was used for benchtop testing, and 6 female porcine subjects were used for in vivo testing after obtaining institutional approval. A modified porcine urethral model that patterned the human female urethral anatomy with approximately 4.5 cm urethral length was used. A HF-10 digital force gauge measured the force required to remove stents with varying properties (stent size, presence of curl, and size of distal magnetic bead). These force measurements were compared to the quantified magnetic forces generated by external magnets and catheter tip magnets. Furthermore, the magnetic retrieval devices were tested with various magnetic beads on both benchtop and porcine models. RESULTS: The required force for removal of a 5 Fr x 14 cm double J stent was significantly higher in the benchtop model compared to the porcine model (4.7N v. 0.8N, p < 0.001). Forces of at least 1N were required from the external magnets to move the stent and bead across a 4-5 cm distance from the bladder neck to the urethral meatus. External magnets at a distance of 4-5 cm produced insufficient forces for removal, and thus they failed to remove the magnetic bead and stent from the bladder. The catheter-based retrieval device showed better success with a variety of different magnet pairs on the retrieval device and stent. Furthermore, the addition of saline to the bladder allowed for better retrieval rates of the smallest beads, even by the smallest magnetic tip catheters. CONCLUSIONS: The forces required for ureteral stent removal are <1N in the porcine model, and improved benchtop models that emulate such parameters will facilitate future stent removal device testing. Given this threshold, external magnets did not generate sufficient force for stent removal at the required distance of 4-5 cm, whereas catheter tip magnetic retrieval overcomes the minimum distance limitation and showed successful retrieval. While these results are encouraging, further studies will define the optimal combination of catheter magnetic tip size and stent magnetic bead size.

Inyecciones Intralesionales de 5-Fluorouracilo: tratamiento innovador y efectivo de Pterigión Primario

Objetivo: Determinar la efectividad de 5-Fluorouracilo intralesional en el alivio sintomático, astigmatismo y deseo de cirugía en pacientes con pterigión primario. Métodos: Estudio experimental realizado entre enero y marzo de 2020 en la Unidad de Oftalmología del Hospital del Salvador, Chile. Se seleccionaron 14 ojos (14 pacientes) en lista de espera quirúrgica, expuestos a inyecciones intralesionales quincenales de 10 mg de 5-FU. Se realizó una evaluación clínica inicial con OSDI para medición sintomática, cámara fotográfica y lámpara de hendidura para apariencia clínica, y autorrefractómetro para astigmatismo, siendo reevaluados 60 días después, añadiéndose la pregunta de si mantenían el deseo de operarse. Se dividió la muestra en grupo A y B según recibieron dos o una dosis de 5-FU, respectivamente. Resultados: La edad promedio de los participantes fue 56,8 ± 11,1 años. El grupo A presentó un OSDI inicial de 50 ± 23,8 que, posterior a la intervención, se redujo a 21 ± 13,5 (p < 0,001). El grupo B tuvo un OSDI inicial de 47 ± 17,3, disminuyendo a 22 ± 16,2 (p < 0,005). Ambos cambios estadísticamente significativos. En cuanto al aspecto físico, hubo reducción del tamaño lesional en 2 de los 14 pacientes, ambos del grupo A. No hubo cambios respecto al grado de astigmatismo. Hubo 2 pacientes que decidieron no realizarse la cirugía posterior a la intervención. Conclusión: La inyección intralesional de 5-FU demostró mejoría significativa en el alivio sintomático, sin complicaciones asociadas, generando un tratamiento alternativo al quirúrgico en pacientes con pterigión primario, pudiendo posponer la cirugía.

Objectives: To determine the effectiveness of intralesional 5-Fluorouracil (5-FU) in symptomatic relief, astigmatism, and desire for surgery in patients with primary pterygium. Methods: The experimental study was carried out between January and March 2020 in the Ophthalmology Unit of the Hospital del Salvador, Chile. Fourteen eyes (14 patients) were selected on the surgical waiting list and exposed to fortnightly intralesional injections of 10 mg of 5-FU. An initial evaluation was performed with OSDI for symptomatic measurement, a photographic camera and slit lamp for clinical appearance, and an auto-refractometer for astigmatism, being re-evaluated 60 days later, adding the question of whether they maintained the desire to undergo surgery. The sample was divided into groups A and B depending on whether they received two or one dose of 5-FU, respectively. Results: The average age of the participants was 56.8 ± 11.1 years. Group A presented an initial OSDI of 50 ± 23.8, which, after the intervention, decreased to 21 ± 13.5 (p < 0.001). Group B had an initial OSDI of 47 ± 17.3, decreasing to 22 ± 16.2 (p < 0.005)-statistically significant changes. The degree of astigmatism had no changes. Regarding the physical aspect, there was a reduction in the size of the lesion in 2 of the 14 patients, both in group A. Two patients decided not to undergo surgery after the intervention. Conclusions: The intralesional injection of 5-FU showed a significant improvement in symptomatic relief without associated complications, generating a therapeutic alternative in patients with primary pterygium without surgical indication.

Modeling Percolation in Polymer Nanocomposites by Stochastic Microstructuring.

A methodology was developed for the prediction of the electrical properties of carbon nanotube-polymer nanocomposites via Monte Carlo computational simulations. A two-dimensional microstructure that takes into account waviness, fiber length and diameter distributions is used as a representative volume element. Fiber interactions in the microstructure are identified and then modeled as an equivalent electrical circuit, assuming one-third metallic and two-thirds semiconductor nanotubes. Tunneling paths in the microstructure are also modeled as electrical resistors, and crossing fibers are accounted for by assuming a contact resistance associated with them. The equivalent resistor network is then converted into a set of linear equations using nodal voltage analysis, which is then solved by means of the Gauss-Jordan elimination method. Nodal voltages are obtained for the microstructure, from which the percolation probability, equivalent resistance and conductivity are calculated. Percolation probability curves and electrical conductivity values are compared to those found in the literature.