Gracias al autor Dr. Lan Qin y Stanek Shane para ayudar con la recolección de datos.

<ol>
	<li>Low, P. A., Denq, J. C., Opfer-Gehrking, T. L., Dyck, P. J., O'Brien, P. C., Slezak, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+age+and+gender+on+sudomotor+and+cardiovagal+function+and+blood+pressure+response+to+tilt+in+normal+subjects.">Effect of age and gender on sudomotor and cardiovagal function and blood pressure response to tilt in normal subjects.</a> Muscle Nerve. 20, 1561-1568 (1997).</li><li>Low, P. A., Denq, J. C., Opfer-Gehrking, T. L., Dyck, P. J., O'Brien, P. C., Slezak, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+age+and+gender+on+sudomotor+and+cardiovagal+function+and+blood+pressure+response+to+tilt+in+normal+subjects.">Effect of age and gender on sudomotor and cardiovagal function and blood pressure response to tilt in normal subjects.</a> Muscle Nerve. 20, 1561-1568 (1997).</li><li>Low, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Composite+autonomic+scoring+scale+for+laboratory+quantification+of+generalized+autonomic+failure.">Composite autonomic scoring scale for laboratory quantification of generalized autonomic failure.</a> Mayo Clin Proc. 68, 748-752 (1993).</li><li>Low, P. A., Low, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laboratory+evaluation+of+autonomic+function.">Laboratory evaluation of autonomic function.</a> Clinical Autonomic disorders. , 179-209 (1997).</li><li>Low, P. A., Low, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laboratory+evaluation+of+autonomic+failure.">Laboratory evaluation of autonomic failure.</a> Clinical Autonomic disorders. , 179-209 (2008).</li><li>Novak, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+sympathetic+index+from+Valsalva+maneuver.">Assessment of sympathetic index from Valsalva maneuver.</a> Neurology. , (2011).</li></ol>

Trampas Finalización de la prueba autonómica, en la mayoría de los pacientes sencillo y se puede hacer dentro de una hora. Dificultades particulares de cada paso de la prueba se discute a continuación. Equipo, adquisición de datos y procesamiento de las señales autonómicas. Hay una serie de dificultades relacionadas principalmente con la calidad de los datos. Limpieza inadecuada de la piel puede conducir a exceso de ruido en la señal del ECG, que puede hacer la detección de la onda R difícil. La colocación inadecuada del sensor de mi presión arterial dar falsos valores altos o bajos. Señal Doppler transcraneal de alta calidad puede ser difícil de conseguir en los pacientes ancianos debido ventana ósea pequeña. Software para el procesamiento de datos pueden no ser lo suficientemente robusta como para distinguir objetos en la presión arterial, por ejemplo, en los pacientes de Parkinson con temblor. La respiración profunda <ol><li> La ansiedad y el patrón de respiración anormal puede afectar los resultados de la respiración profunda. Tema debe estar bien relajada durante la prueba. Un buen indicador de la ansiedad es el perfil de la frecuencia cardíaca. Si el sujeto está ansioso, la frecuencia cardíaca puede ser elevado. Antes de comenzar la prueba de respiración profunda, asegúrese de que el ritmo del corazón no es una tendencia hacia arriba o abajo, si esto ocurrió esperar a que la frecuencia cardiaca media se mantiene plana. El patrón respiratorio en reposo debe ser normal, por ejemplo, no debe haber hiperventilación (medida por el CO 2 espirado) o taquipnea (frecuencia respiratoria supera el 11 por minuto). </li><li> La prueba de respiración profunda tiene una utilidad limitada en la disritmia cardiaca ciertas por ejemplo, en la fibrilación auricular o cuando la frecuencia cardíaca está controlada por un marcapasos debido a la modulación del nervio vago del corazón será anular, ya sea el corazón generado por el ritmo o un marcapasos. Conocimiento básico de las alteraciones del ritmo cardiaco se recomienda. </li><li> Detección incorrecta de R artefactos olas debido, obviamente, se producirán errores en los resultados. Esto puede ocurrido si las ondas R son demasiado pequeños para detectar de forma fiable, o si el fondo de ECG es ruidoso, por ejemplo, ponerse en contacto por la piel pobres. </li></ol> Maniobra de Valsalva Maniobra de Valsalva, se requiere la cooperación considerable de los sujetos Muchos pacientes ancianos o frágiles no pueden realizar correctamente la maniobra de Valsalva. Razón más común es la debilidad de los músculos de la boca que se traduce en pérdida de aire durante el esfuerzo respiratorio. En este caso, es eficaz para sellar la fuga suave de aire alrededor del tubo con los dedos 6. Evaluación de las funciones adrenérgicos no se puede hacer en una variante de onda cuadrada de la maniobra de Valsalva (Figura 10). Esta respuesta es rara pero puede ser observada en voluntarios sanos o en pacientes con insuficiencia cardíaca congestiva. Inclinación de las pruebas Número de medicamentos que pueden afectar a la prueba de inclinación interpretación representación de la difícil prueba. Que no siempre es práctico para suspender la medicación antes de la prueba. Puede ser difícil de obtener grabaciones de calidad en los trastornos del movimiento pacientes, por ejemplo, en los pacientes de Parkinson con temblor. Sudomotoras prueba (QSART) <ol><li> Eliminación incompleta de la superficie aceitosa o irritación de la piel en exceso puede afectar la producción de sudor. </li><li> Las fugas, si la cápsula no es hermética o el dolor causado por demasiado apretado cápsula </li><li> Medicamentos de uso común tiene un efecto anticolinérgico que interfiere con la prueba del sudor. En muchos casos, es poco práctico en éstos se deben descontinuar la interpretación de los resultados de la prestación medicamentos difíciles. </li></ol> Clasificación de la insuficiencia autonómica mediante la puntuación de gravedad compuesto autonómica (CASS). Generación de resultados CASS es bastante complicado porque se trata de comparaciones múltiples en términos absolutos y valores de porcentaje. Desafortunadamente, no hay software comercial que permite calcular la puntuación de forma automática. La Universidad de Massachusetts, se utiliza software propietario que genera el puntaje CASS automáticamente. Ejemplo de las puntuaciones de CASS es en la tabla 8.

Tabla 9 equipos recomendados. <table border="1"><tbody><tr><td> Nombre del equipo </td><td> Empresa </td><td> Comentarios </td></tr><tr><td> Inclinación motorizada mesa </td><td> WR médico electrónico </td><td> La mesa con un movimiento suave llegar a 70 grados en cuestión de segundos 50-10 </td></tr><tr><td> El monitor ECG </td><td></td><td> Cualquier dispositivo con salida analógica </td></tr><tr><td> No invasivos de latido a latido monitor de presión arterial </td><td> Finapres Medical Systems </td><td> Hay varios modelos disponibles, todos son similares </td></tr><tr><td> Q-sudor </td><td> WR médico electrónico </td><td></td></tr><tr><td> Doppler transcraneal </td><td></td><td> Cualquier dispositivo con salida analógica </td></tr><tr><td> Sistema de grabación </td><td> LabChart, ADInstruments </td><td> Programación sencilla </td></tr><tr><td> Sistema de grabación </td><td> Labview </td><td> Programación compleja </td></tr><tr><td> Sistema de grabación </td><td> Matlab </td><td> Programación compleja </td></tr><tr><td> Sistema de grabación </td><td> WR Médico </td><td> Flexibilidad listo para usar, pero limitadas </td></tr><tr><td> Monitor de CO2 </td><td></td><td> Muchos de los modelos utilizados para los estudios del sueño </td></tr><tr><td> Vigilar las vías respiratorias </td><td></td><td> Termistor sencilla conectada a un sistema de grabación </td></tr></tbody></table>

quantitative autonomic testing

Los trastornos asociados con la disfunción del sistema nervioso autónomo son muy comunes todavía no reconocidos con frecuencia. Pruebas autónomas cuantitativo puede ser una herramienta invaluable para la evaluación de estos trastornos, tanto en la clínica y la investigación. Hay una serie de pruebas autónomo, sin embargo, sólo unos pocos se han validado clínicamente o cuantitativos. En este caso, el protocolo totalmente cuantitativa y validado clínicamente para las pruebas de las funciones autonómicas se presenta. Como mínimo el laboratorio autonómico clínica debe tener una mesa basculante, monitor de ECG, monitoreo continuo no invasivo de la presión arterial, controlar las vías respiratorias y una media para la evaluación del dominio sudomotoras. El software para el registro y evaluación de las pruebas autonómica es fundamental para la correcta evaluación de los datos. El protocolo presentado evalúa tres grandes ámbitos autonómico: cardiovagal adrenérgicos, y sudomotoras. Las pruebas incluyen la respiración profunda, la maniobra de Valsalva, inclinación de la cabeza-, y la prueba cuantitativa axonal sudomotoras (QSART). La gravedad y la distribución de disautonomía se cuantificaron utilizando compuestos Scores de Severidad autonómica (CASS). Protocolo detallado es siempre destacando los aspectos esenciales de la prueba, con énfasis en la adquisición de datos adecuados, la obtención de los parámetros relevantes y la evaluación imparcial de las señales autonómicas. Los datos normativos y el algoritmo de CASS para la interpretación de los resultados son siempre así.

Watch this Scientific Journal Video about Quantitative Autonomic Testing at JoVE.com

Quantitative Autonomic Testing

Las pruebas estandarizadas, completa y cuantitativa completa de las funciones autonómicas se describe. Las pruebas consisten en la evaluación autonómica de los tres ámbitos principales autónomo, incluyendo adrenérgicos cardiovagal y sudomotoras. La gravedad y la distribución de disautonomía se cuantificaron utilizando compuestos Scores de Severidad autonómica.

Prueba Autonómica cuantitativa

Disorders associated with dysfunction of autonomic nervous system are quite common yet frequently unrecognized. Quantitative autonomic testing can be ...

Research

Education

JoVE Core

JoVE Journal

Pharmacology

Medicine

Unit 1

Drugs Acting on Autonomic Nervous System: Cholinergic Agonists and Antagonists Agents

SCIENTISTS IN ACTION

56.3K vistas.  University of Massachusetts Medical School. Las pruebas estandarizadas, completa y cuantitativa completa de las funciones autonómicas se describe. Las pruebas consisten en la evaluación autonómica de los tres ámbitos principales autónomo, incluyendo adrenérgicos cardiovagal y sudomotoras. La gravedad y la distribución de disautonomía se cuantificaron utilizando compuestos Scores de Severidad autonómica.

Video: Quantitative Autonomic Testing

Quantitative Analysis of Chromatin Proteomes in Disease

In the nucleus reside the proteomes whose functions are most intimately linked with gene regulation. Adult mammalian cardiomyocyte nuclei are unique due to the high percentage of binucleated cells,1 the predominantly heterochromatic state of the DNA, and the non-dividing nature of the cardiomyocyte which renders adult nuclei in a permanent state of interphase.2 Transcriptional regulation during development and disease have been well studied in this organ,3-5 but what remains relatively unexplored is the role played by the nuclear proteins responsible for DNA packaging and expression, and how these proteins control changes in transcriptional programs that occur during disease.6 In the developed world, heart disease is the number one cause of mortality for both men and women.7 Insight on how nuclear proteins cooperate to regulate the progression of this disease is critical for advancing the current treatment options.
Mass spectrometry is the ideal tool for addressing these questions as it allows for an unbiased annotation of the nuclear proteome and relative quantification for how the abundance of these proteins changes with disease. While there have been several proteomic studies for mammalian nuclear protein complexes,8-13 until recently14 there has been only one study examining the cardiac nuclear proteome, and it considered the entire nucleus, rather than exploring the proteome at the level of nuclear sub compartments.15 In large part, this shortage of work is due to the difficulty of isolating cardiac nuclei. Cardiac nuclei occur within a rigid and dense actin-myosin apparatus to which they are connected via multiple extensions from the endoplasmic reticulum, to the extent that myocyte contraction alters their overall shape.16 Additionally, cardiomyocytes are 40% mitochondria by volume17 which necessitates enrichment of the nucleus apart from the other organelles. Here we describe a protocol for cardiac nuclear enrichment and further fractionation into biologically-relevant compartments. Furthermore, we detail methods for label-free quantitative mass spectrometric dissection of these fractions-techniques amenable to in vivo experimentation in various animal models and organ systems where metabolic labeling is not feasible.

Advances in mass spectrometry have allowed the high throughput analysis of protein expression and modification in a host of tissues. Combined with subcellular fractionation and disease models, quantitative mass spectrometry and bioinformatics can reveal new properties in biological systems. The method described herein analyzes chromatin-associated proteins in the setting of heart disease and is readily applicable to other in vivo models of human disease.

Análisis cuantitativo de proteomas cromatina en la enfermedad

In the nucleus reside the proteomes whose functions are most intimately linked with gene regulation. Adult mammalian cardiomyocyte nuclei are unique due ...

Investigación

Medicina

Measuring Cardiac Autonomic Nervous System (ANS) Activity in Children

The autonomic nervous system (ANS) controls mainly automatic bodily functions that are engaged in homeostasis, like heart rate, digestion, respiratory rate, salivation, perspiration and renal function. The ANS has two main branches: the sympathetic nervous system, preparing the human body for action in times of danger and stress, and the parasympathetic nervous system, which regulates the resting state of the body.
ANS activity can be measured invasively, for instance by radiotracer techniques or microelectrode recording from superficial nerves, or it can be measured non-invasively by using changes in an organ's response as a proxy for changes in ANS activity, for instance of the sweat glands or the heart. Invasive measurements have the highest validity but are very poorly feasible in large scale samples where non-invasive measures are the preferred approach. Autonomic effects on the heart can be reliably quantified by the recording of the electrocardiogram (ECG) in combination with the impedance cardiogram (ICG), which reflects the changes in thorax impedance in response to respiration and the ejection of blood from the ventricle into the aorta. From the respiration and ECG signals, respiratory sinus arrhythmia can be extracted as a measure of cardiac parasympathetic control. From the ECG and the left ventricular ejection signals, the preejection period can be extracted as a measure of cardiac sympathetic control. ECG and ICG recording is mostly done in laboratory settings. However, having the subjects report to a laboratory greatly reduces ecological validity, is not always doable in large scale epidemiological studies, and can be intimidating for young children. An ambulatory device for ECG and ICG simultaneously resolves these three problems.
Here, we present a study design for a minimally invasive and rapid assessment of cardiac autonomic control in children, using a validated ambulatory device 1-5, the VU University Ambulatory Monitoring System (VU-AMS, Amsterdam, the Netherlands,<a href="http://www.vu-ams.nl" target="_blank"> www.vu-ams.nl</a>).

Measuring Cardiac Autonomic Nervous System ANS Activity in Children

Measurement of autonomic nervous system activity usually confines the researcher and participant to the laboratory, which may provide an intimidating environment to children. The VU University Ambulatory Monitoring System (VU-AMS) device can record cardiac autonomic control in any setting. The VU-AMS proved very amenable to testing in children.

Sistema de medición de actividad nerviosa autonómica cardiaca (ANS) en los niños

The autonomic nervous system (ANS) controls mainly automatic bodily functions that are engaged in homeostasis, like heart rate, digestion, respiratory ...

Minimal Erythema Dose (MED) Testing

Ultraviolet radiation (UV) therapy is sometimes used as a treatment for various common skin conditions, including psoriasis, acne, and eczema. The dosage of UV light is prescribed according to an individual's skin sensitivity. Thus, to establish the proper dosage of UV light to administer to a patient, the patient is sometimes screened to determine a minimal erythema dose (MED), which is the amount of UV radiation that will produce minimal erythema (sunburn or redness caused by engorgement of capillaries) of an individual's skin within a few hours following exposure. This article describes how to conduct minimal erythema dose (MED) testing. There is currently no easy way to determine an appropriate UV dose for clinical or research purposes without conducting formal MED testing, requiring observation hours after testing, or informal trial and error testing with the risks of under- or over-dosing. However, some alternative methods are discussed.

Minimal Erythema Dose MED Testing

This article describes how to conduct minimal erythema dose (MED) testing in order to determine the lowest dose of ultraviolet radiation that will cause erythema (burning) when administered to an individual.

Dosis Pruebas Eritema Mínima (MED)

Ultraviolet radiation (UV) therapy is  sometimes used as a treatment for various common skin conditions, including  psoriasis, acne, and eczema. The ...

A Novel Application of Musculoskeletal Ultrasound Imaging

Ultrasound is an attractive modality for imaging muscle and tendon motion during dynamic tasks and can provide a complementary methodological approach for biomechanical studies in a clinical or laboratory setting. Towards this goal, methods for quantification of muscle kinematics from ultrasound imagery are being developed based on image processing. The temporal resolution of these methods is typically not sufficient for highly dynamic tasks, such as drop-landing. We propose a new approach that utilizes a Doppler method for quantifying muscle kinematics. We have developed a novel vector tissue Doppler imaging (vTDI) technique that can be used to measure musculoskeletal contraction velocity, strain and strain rate with sub-millisecond temporal resolution during dynamic activities using ultrasound. The goal of this preliminary study was to investigate the repeatability and potential applicability of the vTDI technique in measuring musculoskeletal velocities during a drop-landing task, in healthy subjects. The vTDI measurements can be performed concurrently with other biomechanical techniques, such as 3D motion capture for joint kinematics and kinetics, electromyography for timing of muscle activation and force plates for ground reaction force. Integration of these complementary techniques could lead to a better understanding of dynamic muscle function and dysfunction underlying the pathogenesis and pathophysiology of musculoskeletal disorders.

We describe a new ultrasound-based vector tissue Doppler imaging technique to measure muscle contraction velocity, strain and strain rate with sub-millisecond temporal resolution during dynamic activities. This approach provides complementary measurements of dynamic muscle function and could lead to a better understanding of mechanisms underlying musculoskeletal disorders.

Una aplicación Novel of Musculoskeletal Ultrasound Imaging

Ultrasound is an attractive modality for imaging muscle and tendon  motion during dynamic tasks and can provide a complementary methodological  approach ...

Cerebrospinal Fluid MicroRNA Profiling Using Quantitative Real Time PCR

MicroRNAs (miRNAs) constitute a potent layer of gene regulation by guiding RISC to target sites located on mRNAs and, consequently, by modulating their translational repression. Changes in miRNA expression have been shown to be involved in the development of all major complex diseases. Furthermore, recent findings showed that miRNAs can be secreted to the extracellular environment and enter the bloodstream and other body fluids where they can circulate with high stability. The function of such circulating miRNAs remains largely elusive, but systematic high throughput approaches, such as miRNA profiling arrays, have lead to the identification of miRNA signatures in several pathological conditions, including neurodegenerative disorders and several types of cancers. In this context, the identification of miRNA expression profile in the cerebrospinal fluid, as reported in our recent study, makes miRNAs attractive candidates for biomarker analysis.
There are several tools available for profiling microRNAs, such as microarrays, quantitative real-time PCR (qPCR), and deep sequencing. Here, we describe a sensitive method to profile microRNAs in cerebrospinal fluids by quantitative real-time PCR. We used the Exiqon microRNA ready-to-use PCR human panels I and II V2.R, which allows detection of 742 unique human microRNAs. We performed the arrays in triplicate runs and we processed and analyzed data using the GenEx Professional 5 software.
Using this protocol, we have successfully profiled microRNAs in various types of cell lines and primary cells, CSF, plasma, and formalin-fixed paraffin-embedded tissues.

We describe a protocol of real time PCR to profile microRNAs in the cerebrospinal fluid (CSF). With the exception of RNA extraction protocols, the procedure can be extended to RNA extracted from other body fluids, cultured cells, or tissue specimens.

Líquido cefalorraquídeo MicroRNA perfiles utilizando cuantitativa en tiempo real PCR

MicroRNAs (miRNAs) constitute a potent layer of gene regulation by guiding RISC to target sites located on mRNAs and, consequently, by modulating their ...

Development of an Algorithm to Perform a Comprehensive Study of Autonomic Dysreflexia in Animals with High Spinal Cord Injury Using a Telemetry Device

Spinal cord injury (SCI) is a debilitating neurological condition characterized by somatic and autonomic dysfunctions. In particular, SCI above the mid-thoracic level can lead to a potentially life-threatening hypertensive condition called autonomic dysreflexia (AD) that is often triggered by noxious or non-noxious somatic or visceral stimuli below the level of injury. One of the most common triggers of AD is the distension of pelvic viscera, such as during bladder and bowel distension or evacuation. This protocol presents a novel pattern recognition algorithm developed for a JAVA platform software to study the fluctuations of cardiovascular parameters as well as the number, severity and duration of spontaneously occurring AD events. The software is able to apply a pattern recognition algorithm on hemodynamic data such as systolic blood pressure (SBP) and heart rate (HR) extracted from telemetry recordings of conscious and unrestrained animals before and after thoracic (T3) complete transection. With this software, hemodynamic parameters and episodes of AD are able to be detected and analyzed with minimal experimenter bias.

The catheter of a telemetry device is implanted into the abdominal aorta in order to continuously collect beat-by-beat hemodynamic data from animals pre and post-high thoracic spinal cord transection. A novel JAVA software was employed to analyze hemodynamic parameters as well as frequency and intensity of spontaneous episodes of autonomic dysreflexia.

Desarrollo de un algoritmo de realizar un estudio exhaustivo de Disreflexia Autónoma en animales con lesión medular alta El uso de un dispositivo de telemetría

Spinal cord injury (SCI) is a debilitating neurological condition characterized by somatic and autonomic dysfunctions. In particular, SCI above the ...

Measuring Cardiac Autonomic Nervous System (ANS) Activity in Toddlers - Resting and Developmental Challenges

The autonomic nervous system (ANS) consists of two branches, the parasympathetic and sympathetic nervous systems, and controls the function of internal organs (e.g., heart rate, respiration, digestion) and responds to everyday and adverse experiences 1. ANS measures in children have been found to be related to behavior problems, emotion regulation, and health 2-7. Therefore, understanding the factors that affect ANS development during early childhood is important. Both branches of the ANS affect young children&#8217;s cardiovascular responses to stimuli and have been measured noninvasively, via external monitoring equipment, using valid and reliable measures of physiological change 8-11. However, there are few studies of very young children with simultaneous measures of the parasympathetic and sympathetic nervous systems, which limits understanding of the integrated functioning of the two systems. In addition, the majority of existing studies of young children report on infants&#8217; resting ANS measures or their reactivity to commonly used mother-child interaction paradigms, and less is known about ANS reactivity to other challenging conditions. We present a study design and standardized protocol for a non-invasive and rapid assessment of cardiac autonomic control in 18 month old children. We describe methods for continuous monitoring of the parasympathetic and sympathetic branches of the ANS under resting and challenge conditions during a home or laboratory visit and provide descriptive findings from our sample of 140 ethnically diverse toddlers using validated equipment and scoring software. Results revealed that this protocol can produce a range of&#160;physiological responses to both resting and developmentally challenging conditions, as indicated by changes in heart rate and indices of parasympathetic and sympathetic activity. Individuals demonstrated&#160;variability in resting levels, responses to challenges, and challenge reactivity, which provides additional evidence that this protocol is useful for the examination of ANS individual differences for toddlers.

Measuring Cardiac Autonomic Nervous System ANS Activity in Toddlers - Resting and Developmental Challenges

We describe the methods for continuous monitoring of the autonomic nervous system under resting and challenge conditions with 18 month old children. Results revealed that this protocol can produce meaningful physiological responses in both branches of the autonomic nervous system and elicit significant individual variability in patterns of responses.

La medición del sistema nervioso autónomo cardíaco (ANS) La actividad en los niños pequeños - Descansar y Desafíos del Desarrollo

The autonomic nervous system (ANS) consists of two branches, the parasympathetic and sympathetic nervous systems, and controls the function of internal ...

Proximal Cadaveric Femur Preparation for Fracture Strength Testing and Quantitative CT-based Finite Element Analysis

Cadaveric fracture testing is routinely used to understand factors that affect proximal femur strength. Because ex vivo biological tissues are prone to lose their mechanical properties over time, specimen preparation for experimental testing must be performed carefully to obtain reliable results that represent in vivo conditions. For that reason, we designed a protocol and a set of fixtures to prepare the femoral specimens such that their mechanical properties experienced minimal changes. The femora were kept in a frozen state except during preparation steps and mechanical testing. The relevant clinical measures of total hip and femoral neck bone mineral density (BMD) were obtained with a clinical dual X-ray absorptiometry (DXA) bone densitometer, and the 3D geometry and distribution of bone mineral were obtained using CT with a calibration phantom for quantitative estimations based on the greyscale values. Any possible bone disease, fracture, or the presence of implants or artifacts affecting the bone structure, was ruled out with X-ray scans. For preparation, all bones were carefully cleaned of excess soft tissue, and were cut and potted at the internal rotation angle of interest. A cutting fixture allowed the distal end of the bone to be cut off leaving the proximal femur at a desired length. To allow positioning of the femoral neck at prescribed angles during later CT scanning and mechanical testing, the proximal femoral shafts were potted in polymethylmethacrylate (PMMA) using a fixture designed specifically for desired orientations. The data collected from our experiments were then used for validation of quantitative computed tomography (QCT)-based finite element analysis (FEA), as described in a different protocol. In this manuscript, we present the protocol for the precise bone preparation for mechanical testing and subsequent QCT/FEA modeling. The current protocol was successfully applied to prepare about 200 cadaveric femora over a 6-year time period.

We present a robust protocol on how to carefully preserve and prepare cadaveric femora for fracture testing and quantitative computed tomography imaging. The method provides precise control over input conditions for the purpose of determining relationships between bone mineral density, fracture strength, and defining finite element model geometry and properties.

Proximal del fémur de cadáver preparación para el análisis de elementos finitos basado en CT Fracture Fuerza Pruebas y cuantitativa

Cadaveric fracture testing is routinely used to understand factors that affect proximal femur strength.  Because ex vivo biological tissues are prone to ...

A Quantitative Sensory Testing Paradigm to Obtain Measures of Pain Processing in Patients Undergoing Breast Cancer Surgery

Chronic pain following surgery, persistent postsurgical pain, is an important highly prevalent condition contributing to significant symptom burden and lower quality of life. Persistent postsurgical pain is relatively refractory to treatment hence generating a high need for preventive strategies and treatments. Therefore, the identification of patients at risk of developing persistent pain is an area of active ongoing research. Recently it was demonstrated that peri-operative disruptions in central pain processing may be able to predict persistent postsurgical pain at long term follow-up in breast cancer patients. The aim of the current report is to present a short protocol to obtain pain thresholds to different stimuli at multiple sites and a measure of endogenous analgesia in breast cancer patients. We have used this method successfully in a clinical context and detail some representative results from a clinical study.

Persistent postsurgical pain may be related to changes in pain processing. By assessing pain in response to standardized stimuli, changes in pain processing can be elucidated. We present methods to obtain pain thresholds to different stimuli and a measure of endogenous analgesia in patients undergoing breast cancer surgery.

Un paradigma de prueba sensorial cuantitativo para obtener medidas del dolor en pacientes sometidos a cirugía de cáncer de mama

Chronic pain following surgery, persistent postsurgical pain, is an important highly prevalent condition contributing to significant symptom burden and ...

Autonomic Function Following Concussion in Youth Athletes: An Exploration of Heart Rate Variability Using 24-hour Recording Methodology

Participation in organized sports makes a significant contribution to youth development, but places youth at a higher risk for sustaining a concussion. To date, return-to-activity decision-making has been anchored in the monitoring of self-reported concussion symptoms and neurocognitive testing. However, multi-modal assessments that corroborate objective physiological measures with traditional subjective symptom reporting are needed and can be valuable. Heart rate variability (HRV) is a non-invasive physiological indicator of the autonomic nervous system, capturing the reciprocal interplay between the sympathetic and parasympathetic nervous systems. There is a dearth of literature exploring the effect of concussion on HRV in youth athletes, and developmental differences preclude the application of adult findings to a pediatric population. Further, the current state of HRV methodology has primarily included short-term (5-15 min) recordings, by using resting state or short-term physical exertion testing to elucidate changes following concussion. The novelty in utilizing a 24 h&#160;recording methodology is that it has the potential to capture natural variation in autonomic function, directly related to the activities a youth athlete performs on a regular basis. Within a prospective, longitudinal research setting, this novel approach to quantifying autonomic function can provide important information regarding the recovery trajectory, alongside traditional self-report symptom measures. Our objectives regarding a 24 h recording methodology were to (1) evaluate the physiological effects of a concussion in youth athletes, and (2) describe the trajectory of physiological change, while considering the resolution of self-reported post-concussion symptoms. To achieve these objectives, non-invasive sensor technology was implemented. The raw beat-to-beat time intervals captured can be transformed to derive time domain and frequency domain measures, which reflect an individual&#39;s ability to adapt and be flexible to their ever-changing environment. By using non-invasive heart rate technology, autonomic function can be quantified outside of a traditional controlled research setting.

We demonstrate a 24 h heart rate recording methodology to evaluate the influence of concussion across the recovery trajectory in youth athletes, within an ecologically valid context.

Función autonómica después de conmoción cerebral en atletas jóvenes: una exploración de la variabilidad del ritmo cardíaco utilizando metodología de grabación de 24 horas

Participation in organized sports makes a significant contribution to youth development, but places youth at a higher risk for sustaining a concussion. To ...