Biology subjects

Rodriguez, C. A.

Publications and source records attributed to Rodriguez, C. A..

4 recordsLinked to original sources

bioRxiv2024

Intrastromal graft of anterior lens capsule. A substitute for Bowman layer graft transplantation for keratoconus.

PurposeThe shortage of donor corneas limits Bowman layer transplantation for keratoconus. In this study, we evaluate the clinical outcome of anterior lens capsule xenograft transplantation in the corneal stroma of a rabbit model as substitute for Bowman layer graft that is used in stromal transplantation for advanced keratoconus. MethodsTransplantation of an anterior lens capsule in the corneal stroma was performed in four New Zealand white rabbits through the creation of a stromal pocket. Corneal transparency, central corneal thickness, and topographic characteristics of corneas were evaluated at different time points: pre- (0) and post- (7, 14, 21, and 28) operative days. Additionally, at the end of the study histopathological findings were evaluated. ResultsIn comparison to pre-operative day, transplantation of an anterior lens capsule preserved corneal transparency, central corneal thickness, and topographic characteristics remained constant throughout the study period. Histopathological analysis revealed the presence of the anterior lens capsule as a fully integrated lamellar graft without adverse effects in host stroma. ConclusionThe anterior lens capsule may be useful as a graft for intrastromal corneal trasplantation. Similarly to Bowman layer, anterior lens capsule has mechanical characteristics that facilitate corneal transplantation. In post-transplanted corneas the preservation of transparency, as well as the effect on corneal thickness, and topographic characteristics support the possibility of using anterior lens capsule as a substitute for Bowman layer graft.

bioengineering↗

bioRxiv2023

Validation of a multiplex microsphere immunoassay for detection of Trypanosoma cruzi antibodies in dogs

The vector-borne protozoan parasite Trypanosoma cruzi causes Chagas disease in humans, dogs, and many other mammalian hosts. Canine Chagas disease is increasingly diagnosed in dogs of the southern US where triatomine insect vectors occur, and there are limited veterinary diagnostic options; currently, only the indirect fluorescent antibody (IFA) test is offered at a single accredited diagnostic laboratory. This study evaluated a multiplex microsphere immunoassay (MIA) for detecting antibodies against T. cruzi in dogs and compared with existing serological methods to establish cut-off values and relative sensitivity/specificity. Dog sera (n=135) which were previously characterized using the IFA and off-label use of two commercial rapid assays were tested on the multiplex MIA against 12 different antigens: nine T. cruzi antigens, a negative control recombinant protein (green fluorescent protein), a Leishmania antigen, and a canine parvovirus antigen (used as an antibody control given near-ubiquitous parvovirus vaccination). For each sample, the ratio of median fluorescence intensity (MFI) for each T. cruzi antigen to that of GFP was calculated. Samples with an antigen/GFP ratio greater than 4 standard deviations above the mean of 25 known negative sera were considered positive on that antigen. Samples testing positive on 2 or more antigens were considered positive for T. cruzi antibodies. Compared to the IFA, the multiplex MIA demonstrated a relative sensitivity of 100% and specificity of 96.97%. Given its precision, high-throughput format, potential for automation, and lack of subjective interpretation, the multiplex MIA should be considered a valid and improved assay for T. cruzi antibodies in dogs.

microbiology↗

bioRxiv2022

Cost-effectiveness of quadrivalent versus trivalent inactivated influenza vaccines for the Portuguese elderly population

BackgroundQuadrivalent Inactivated Vaccine (QIV) is expected to replace Trivalent Inactivated Vaccine (TIV) over time. In Portugal, TIV is free of charge for risk groups, which include older adults. In its turn, QIV - which provides broader protection as it includes an additional lineage B strain - was introduced in Portugal in October 2018, but only from the influenza season 2019/20 was provided free of charge for the risk groups. This study evaluates the cost-effectiveness of switching from TIV to QIV from the National Health Service perspective in the Portuguese elderly mainland population ([≥] 65 years old). MethodsA decision tree model was developed to compare TIV and QIV, based on Portuguese hospitalization data for the 2015/16 influenza season. The primary health economic outcome under consideration was the Incremental Cost-Effectiveness Ratio (ICER). In addition, a one-Way Sensitivity Analysis was performed to evaluate the impact of model parameters on the ICER; Probabilistic Sensitivity Analysis was also carried out to analyze the robustness of the base case results. ResultsThe high cost of QIV (approximately three times the cost of TIV) would lead to a total increment of 5,283,047 {euro}, and the resulting ICER would be 26,403,007{euro}/QALY, mainly above the usual willingness-to-pay threshold. ConclusionsFrom the National Health Service perspective, our findings reveal that QIV is not cost-effective for the Portuguese elderly population due to the high cost. If the QIV costs were the same as the TIV, then QIV would be cost-effective.

scientific communication and education↗

bioRxiv2019

Using Chaos for Facile High-throughput Fabrication of Ordered Multilayer Micro- and Nanostructures

This paper introduces the concept of continuous chaotic printing, i.e., the use of chaotic flows for deterministic and continuous fabrication of fibers with internal multilayered micro-or nanostructures. Two free-flowing materials are coextruded through a printhead containing a miniaturized Kenics static mixer (KSM) composed of multiple helicoidal elements. This produces a fiber with a well-defined internal multilayer microarchitecture at high speeds (>1.0 m min-1). The number of mixing elements and the printhead diameter determine the number and thickness of the internal lamellae, which are generated according to successive bifurcations that yield a vast amount of inter-material surface area (~102 cm2 cm3) and high resolution features (~10 m). In an exciting further development, we demonstrate a scale-down of the microstructure by 3 orders of magnitude, to the nanoscale level (~10 nm), by feeding the output of a continuous chaotic 3D printhead into an electrospinner. Comparison of experimental and computational results demonstrates the robust and predictable output and performance of continuous chaotic 3D printing. The simplicity and high resolution of continuous chaotic printing strongly supports its potential use in novel applications, including--but not limited to--bioprinting of multi-scale tissue-like structures, modeling of bacterial communities, and fabrication of smart multi-material and multilayered constructs.

bioengineering↗