A low-cost, multiplexed µECoG system for high-density recordings in freely moving rodents.

OBJECTIVE: Micro-electrocorticography (µECoG) offers a minimally invasive neural interface with high spatial resolution over large areas of cortex. However, electrode arrays with many contacts that are individually wired to external recording systems are cumbersome and make recordings in freely behaving rodents challenging. We report a novel high-density 60-electrode system for µECoG recording in freely moving rats. APPROACH: Multiplexed headstages overcome the problem of wiring complexity by combining signals from many electrodes to a smaller number of connections. We have developed a low-cost, multiplexed recording system with 60 contacts at 406 µm spacing. We characterized the quality of the electrode signals using multiple metrics that tracked spatial variation, evoked-response detectability, and decoding value. Performance of the system was validated both in anesthetized animals and freely moving awake animals. MAIN RESULTS: We recorded µECoG signals over the primary auditory cortex, measuring responses to acoustic stimuli across all channels. Single-trial responses had high signal-to-noise ratios (SNR) (up to 25 dB under anesthesia), and were used to rapidly measure network topography within ∼10 s by constructing all single-channel receptive fields in parallel. We characterized evoked potential amplitudes and spatial correlations across the array in the anesthetized and awake animals. Recording quality in awake animals was stable for at least 30 days. Finally, we used these responses to accurately decode auditory stimuli on single trials. SIGNIFICANCE: This study introduces (1) a µECoG recording system based on practical hardware design and (2) a rigorous analytical method for characterizing the signal characteristics of µECoG electrode arrays. This methodology can be applied to evaluate the fidelity and lifetime of any µECoG electrode array. Our µECoG-based recording system is accessible and will be useful for studies of perception and decision-making in rodents, particularly over the entire time course of behavioral training and learning.

Cadaveric bone marrow mesenchymal stem cells: first experience treating a patient with large severe burns.

BACKGROUND: In January 2005, Rasulov et al. originally published "First experience in the use of bone marrow mesenchymal stem cells (MSCs) for the treatment of a patient with deep skin burns". Here, we present the first ever treated patient with cadaveric bone marrow mesenchymal stem cells (CMSCs) in the history of Medicine. METHODS: A young man, who severely burned 60 % of his total body surface with 30 % of full-thickness burns while working with a grass trimmer that exploded, was involved in the study. MSCs were obtained from the bone marrow of a cadaver donor in a routine procurement procedure of CUCAIBA, the Province of Buenos Aires, Argentina, Ministry of Health, Transplantation Agency, cultured, expanded, and applied on the burned surfaces using a fibrin spray after early escharotomy. RESULTS: So far, our preliminary experience and our early results have been very impressive showing an outstanding safety data as well as some impressive good results in the use of CMSCs. CONCLUSIONS: Based on all this, we think that improvements in the use of stem cells for burns might be possible in the near future and a lot of time as well as many lives could be saved by many other research teams all over the world. CMSCs will probably be a real scientific opportunity in Regenerative Medicine as well as in Transplantation.

Dermal papilla cells improve the wound healing process and generate hair bud-like structures in grafted skin substitutes using hair follicle stem cells.

Tissue-engineered skin represents a useful strategy for the treatment of deep skin injuries and might contribute to the understanding of skin regeneration. The use of dermal papilla cells (DPCs) as a dermal component in a permanent composite skin with human hair follicle stem cells (HFSCs) was evaluated by studying the tissue-engineered skin architecture, stem cell persistence, hair regeneration, and graft-take in nude mice. A porcine acellular dermal matrix was seeded with HFSCs alone and with HFSCs plus human DPCs or dermal fibroblasts (DFs). In vitro, the presence of DPCs induced a more regular and multilayered stratified epidermis with more basal p63-positive cells and invaginations. The DPC-containing constructs more accurately mimicked the skin architecture by properly stratifying the differentiating HFSCs and developing a well-ordered epithelia that contributed to more closely recapitulate an artificial human skin. This acellular dermal matrix previously repopulated in vitro with HFSCs and DFs or DPCs as the dermal component was grafted in nude mice. The presence of DPCs in the composite substitute not only favored early neovascularization, good assimilation and remodeling after grafting but also contributed to the neovascular network maturation, which might reduce the inflammation process, resulting in a better healing process, with less scarring and wound contraction. Interestingly, only DPC-containing constructs showed embryonic hair bud-like structures with cells of human origin, presence of precursor epithelial cells, and expression of a hair differentiation marker. Although preliminary, these findings have demonstrated the importance of the presence of DPCs for proper skin repair.

Correlation between muscular and nerve signals responsible for hand grasping in non-human primates.

Neuroprosthetic devices that interface with the nervous system to restore functional motor activity offer a viable alternative to nerve regeneration, especially in proximal nerve injuries like brachial plexus injuries where muscle atrophy may set in before nerve re-innervation occurs. Prior studies have used control signals from muscle or cortical activity. However, nerve signals are preferred in many cases since they permit more natural and precise control when compared to muscle activity, and can be accessed with much lower risk than cortical activity. Identification of nerve signals that control the appropriate muscles is essential for the development of such a `bionic link'. Here we examine the correlation between muscle and nerve signals responsible for hand grasping in the M. fascicularis. Simultaneous recordings were performed using a 4-channel thin-film longitudinal intra-fascicular electrode (tf-LIFE) and 9 bipolar endomysial muscle electrodes while the animal performed grasping movements. We were able to identify a high degree of correlation (r > 0.6) between nerve signals from the median nerve and movement-dependent muscle activity from the flexor muscles of the forearm, with a delay that corresponded to 25 m/s nerve conduction velocity. The phase of the flexion could be identified using a wavelet approximation of the ENG. This result confirms this approach for a future neuroprosthetic device for the treatment of peripheral nerve injuries.

Modelization of a self-opening peripheral neural interface: a feasibility study.

In this paper a self-opening intrafascicular neural interface (SELINE) has been modeled using both a theoretical approach and a Finite Element (FE) analysis. This innovative self opening interface has several potential advantages such as: higher selectivity due to its three-dimensional structure and efficient anchorage system. Mechanical, structural and micro-technological issues have been considered to obtain an effective design of the electrode, as a feasibility study of the self-opening approach. A simple framework has been provided to model the insertion and partial retraction into peripheral nerves, resulting in the opening of wings. This integrated approach results in a rational procedure to optimize kinematics, geometry, and structural properties of peripheral interfaces. The design and feasibility study carried out in this work can potentially assure a correct behavior and dimensioning of the neural interface: in this way anomalous breakage should be avoided while mechanical and geometrical biocompatibility should increase.

An implantable microactuated intrafascicular electrode for peripheral nerves.

Important advancements have been recently achieved in the field of neural interfaces to restore lost sensory and motor functions. The aim of this letter was to develop an innovative approach to increase the selectivity and the lifetime of polyimide-based intrafascicular electrodes. The main idea was to obtain a neural interface that is able to restore a good signal quality by improving the electrical connection between the active sites and the surrounding axons. The high flexibility of polyimide-based neural interfaces allows to embed microactuators in the interface core and achieve desired microdisplacements of the active sites. Nearly equiatomic nickel-titanium alloy was selected as a microactuator because of its shape memory effect. A single TiNi thin film was obtained by dc magnetron sputtering, and was segmented into four distinct sectors. This solution allowed the independent actuation of the different active sites (multiactuation). A corrugated profile was impressed to the new actuated intraneural (ACTIN) interface. The active sites were positioned in correspondence to the peaks of the corrugation, thus maximizing the effects of the single actuations. The technological results, the electrical properties, the thermal behavior, and eventually, the actuation performances of the current ACTIN prototype are shown and discussed. The actuation cycle was thermally compatible for biomedical applications. Promising results were obtained from the current ACTIN prototype with an average controlled movement of 7 microm of the peaks.

Shape memory alloy microactuation of tf-lIFes: preliminary results.

In this paper, a new approach aimed at improving the performance of intraneural longitudinal interfaces (tf-LIFEs) with the peripheral nervous system (PNS) is presented. Our goal is to develop a movable interface by embedding microactuators into the flexible tf-LIFEs structure. In this way, the optimal position of the electrical contacts can be searched inside the PNS and lost connections with neural cells could be replaced. For this purpose a thin film of shape memory alloy (tf-SMA) was selected. A multisegmented SMA was realized and embedded between two polyimide thin films in order to simulate the tf-LIFE structure. Thermal evaluation, fabrication procedure, the first characterization and preliminary experimental results of the new movable interface are described in the manuscript. A total controllable stroke of about 10 microm was obtained for the presented prototype.

Necrosis cutánea en 30% de la superficie corporal (SCT) en recién nacido pretérmino. Presentación de una caso / Necrotizing fascitis with tissue damage over 30% of body surface area in premature neonate

Las grandes pérdidas de la cobertura cutánea y los fenómenos toxo-inflamatorios que se asocian, ya se trate de quemaduras, necrolisis tóxica epidérmica o porcesos bacterianos productores de toxinas con gran destrucción tisular, configuran una situación clínica crítica con alto riesgo de vida. Con los principios de tratamiento de grandes quemados, el control de la infección local y sistémica, el sostén clínico intensivo en una unidd de máxima complejidad y la adecuada asistencia nutricional y respiratoria se pudo tratar satisfactoriamente una fascitis necrotizante con pérdida de la cobertura cutánea en aproximadamente un 30 por ciento de la SCT causada por una infección de Estreptococo beta hemolítico grupo A en un recién nacido pretérmino (RNPT) de 1287g al nacer.(AU)

Necrosis cutánea en 30% de la superficie corporal (SCT) en recién nacido pretérmino. Presentación de una caso / Necrotizing fascitis with tissue damage over 30% of body surface area in premature neonate

Las grandes pérdidas de la cobertura cutánea y los fenómenos toxo-inflamatorios que se asocian, ya se trate de quemaduras, necrolisis tóxica epidérmica o porcesos bacterianos productores de toxinas con gran destrucción tisular, configuran una situación clínica crítica con alto riesgo de vida. Con los principios de tratamiento de grandes quemados, el control de la infección local y sistémica, el sostén clínico intensivo en una unidd de máxima complejidad y la adecuada asistencia nutricional y respiratoria se pudo tratar satisfactoriamente una fascitis necrotizante con pérdida de la cobertura cutánea en aproximadamente un 30 por ciento de la SCT causada por una infección de Estreptococo beta hemolítico grupo A en un recién nacido pretérmino (RNPT) de 1287g al nacer.

Instrumentacion de normas para la prevención de sida, hepatitis, sifilis y otras enfermedades / Instrumentation of norms to prevent AIDS, hepatitis, syphilis and others diseases

Se analizan las medidas tomadas para la prevención de enfermedades transmisibles en un Hospital monovalente, de máxima complejidad para la asistencia de quemados, las dificultades para la implementación y la experiencia de los autores en el manejo de 7 pacientes con serología (+) para HIV o HBsAg a quienes se le practicaron 66 cirugías desde que se reglamentó se detección en julio de 1988. (AU)

Instrumentacion de normas para la prevención de sida, hepatitis, sifilis y otras enfermedades / Instrumentation of norms to prevent AIDS, hepatitis, syphilis and others diseases

Se analizan las medidas tomadas para la prevención de enfermedades transmisibles en un Hospital monovalente, de máxima complejidad para la asistencia de quemados, las dificultades para la implementación y la experiencia de los autores en el manejo de 7 pacientes con serología (+) para HIV o HBsAg a quienes se le practicaron 66 cirugías desde que se reglamentó se detección en julio de 1988.