Exercise Training Protocols in Rabbits Applied in Cardiovascular Research.

Rabbit exercise protocols allow for the evaluation of physiological and biomechanical changes and responses to episodes of acute or chronic exercise. The observed physiological changes are normal responses to stress, that is, adaptive responses to maintain or restore homeostasis after acute exercise. Indeed, the rabbit model is advantageous since (a) it has important physiological similarities in terms of the functioning of multiple organ systems, and can quickly induce alterations in pathophysiological conditions that resemble those of humans, and (b) it allows the implementation of a low-cost model in comparison with other large animals. When designing an exercise training protocol for rabbits, it is important to consider variables such as race, gender, age and, especially, training parameters such as volume, intensity, or rest, among others, to determine the outcome of the research. Therefore, the objective of this review is to identify and analyze exercise training protocols in rabbits in different experimental applications and the various physiological adaptations that are presented, with special focus in cardiovascular adaptations.

Diet-Induced Metabolic Syndrome Reduced Heart Rate Variability and Increased Irregularity and Complexity of Short-Term RR Time Series in Rabbits.

Metabolic syndrome (MetS) has been linked to a higher prevalence of sudden cardiac death (SCD), but the mechanisms are not well understood. One possible underlying mechanism may be an abnormal modulation of autonomic activity, which can be quantified by analyzing heart rate variability (HRV). Our aim was to investigate the modifications of short-term HRV in an experimental rabbit model during the time-course of MetS development. NZW rabbits were randomly assigned to a control (n = 10) or a MetS group (n = 13), fed 28 weeks with control or high-fat, high-sucrose diets. After anesthesia, a 15-min ECG recording was acquired before diet administration and at weeks 14 and 28. We analyzed short RR time series using time-domain, frequency-domain and nonlinear analyses. A mixed-model factorial ANOVA was used for statistical analysis. Time-domain analysis showed a 52.4% decrease in the standard deviation of heart rate in animals from the MetS group at week 28, but no changes in the rest of parameters. In the frequency domain, we found a 9.7% decrease in the very low frequency and a 380.0% increase of the low frequency bands in MetS animals at week 28, whereas high frequency remained unchanged. Nonlinear analyses showed increased complexity and irregularity of the RR time series in MetS animals.

Diet-Induced Rabbit Models for the Study of Metabolic Syndrome.

Obesity and metabolic syndrome (MetS) have become a growing problem for public health and clinical practice, given their increased prevalence due to the rise of sedentary lifestyles and excessive caloric intake from processed food rich in fat and sugar. There are several definitions of MetS, but most of them describe it as a cluster of cardiovascular and metabolic alterations such as abdominal obesity, reduced high-density lipoprotein (HDL) and elevated low-density lipoprotein (LDL) cholesterol, elevated triglycerides, glucose intolerance, and hypertension. Diagnosis requires three out of these five criteria to be present. Despite the increasing prevalence of MetS, the understanding of its pathophysiology and relationship with disease is still limited. Indeed, the pathological consequences of MetS components have been reported individually, but investigations that have studied the effect of the combination of MeS components on organ pathological remodeling are almost nonexistent. On the other hand, animal models are a powerful tool in understanding the mechanisms that underlie pathological processes such as MetS. In the first part of the review, we will briefly overview the advantages, disadvantages and pathological manifestations of MetS in porcine, canine, rodent, and rabbit diet-induced experimental models. Then, we will focus on the different dietary regimes that have been used in rabbits to induce MetS by means of high-fat, cholesterol, sucrose or fructose-enriched diets and their effects on physiological systems and organ remodeling. Finally, we will discuss the use of dietary regimes in different transgenic strains and special rabbit breeds.

Modifications of short-term intrinsic pacemaker variability in diet-induced metabolic syndrome: a study on isolated rabbit heart.

Metabolic syndrome (MetS) describes a condition associated with multiple diseases concomitantly such as diabetes, hypertension, obesity, and dyslipidemia. It has been linked with higher prevalence of cardiovascular disease, atrial fibrillation, and sudden cardiac death. One of the underlying mechanisms could be altered automaticity, which would reflect modifications of sinus node activity. These phenomena can be evaluated analyzing the components of heart rate variability (HRV). Our aim was to examine the modifications of sinus node variability in an isolated heart model of diet-induced obesity and MetS. Male NZW rabbits were randomly assigned to high-fat (HF, n = 8), control (HF-C, n = 7), high-fat, high-sucrose (HFHS, n = 9), and control (HFHS-C, n = 9) groups, fed with their respective diets during 18/28 weeks. After euthanasia, their hearts were isolated in a Langendorff system. We recorded 10-15 min of spontaneous activity. Short RR time series were analyzed, and standard HRV parameters were determined. One-way ANOVA, Kruskal-Wallis test, and bivariate correlation were used for statistical analysis (p < 0.05). We did find an increase in the complexity and irregularity of intrinsic pacemaker activity as shown by modifications of approximate entropy, sample entropy, minimum multiscale entropy, and complexity index in HFHS animals. Even though no differences were found in standard time and frequency-domain analyses, spectral heterogeneity increased in HFHS group. Animal weight and glucose intolerance were highly correlated with the modifications of intrinsic pacemaker variability. Finally, modifications of intrinsic HRV seemed to be reliant on the number of components of MetS present, given that only HFHS group showed significant changes towards an increased complexity and irregularity of intrinsic pacemaker variability.

Anastomosis Martin-Gruber: Aspectos anatómicos y electrofisiológicos / Martin-Gruber Anastomosis: Anatomical and electrophysiological issues

La anastomosis de Martin Gruber (AMG) es una de las variaciones anatómicas más frecuentes que consiste en la contribución de axones motores desde el nervio mediano hacia el ulnar en el antebrazo. Factores filogenéticos y genéticos se asocian con la aparición de la AMG. Entre tanto, otros factores como género, raza o lateralidad no parecen tener importancia en la aparición de la rama comunicante. Las clasificaciones de la AMG han sido establecidas según los hallazgos anatómicos, electrofisiológicos e histológicos y también según el lugar de origen y destino de la anastomosis. El objetivo de este artículo es revisar los factores asociados a la presencia de la AMG, así como las descripciones y clasificaciones anatómicas y electrofisiológicas. Esta revisión aporta información relevante para el reconocimiento de los patrones clásico y variante de inervación de la musculatura intrínseca de la mano. Dicho reconocimiento permite diagnosticar e intervenir apropiadamente las alteraciones de los nervios periféricos de la extremidad superior.

The Martin Gruber Anastomosis (MGA) is one of the most common anatomical variants of the upper limb, which consists of motor axons crossing through the forearm from the median nerve to the ulnar nerve. Phylogenetic and hereditary factors have been associated whit the MGA. However, gender, race, or laterality, do not seem to have importance in the appearance of the communicating branch. The MGA has been categorized according to findings in anatomy, electrophysiology and histology, in relation to the source and destination of the communicating branch. The aim of this article is to review the factors related to the presence of MGA, as well as the descriptions and classifications according to anatomy and electrophysiology. This revision contributes with important information relevant to the recognition of differences between the classic pattern and the variant pattern of the innervations of the intrinsic muscles of the hand. Such recognition allows a more appropriate diagnostic and intervention of disorders of the peripheral nerves in the upper limb.

Síndrome de west: encefalopatía epiléptica / West syndrome: epileptic encephalopathy

El síndrome de West es un tipo de epilepsia que se presenta principalmente en edades tempranas, se caracteriza por la tríada clásica de espasmos epilépticos, retardo del desarrollo psicomotor y electroencefalograma hipsarrítmico, aunque uno de estos elementos puede estar ausente, desde el punto de vista etiológico se clasifica en idiopático, criptogénico y sintomático. El objetivo de la presente revisión es presentar las características mas importantes del síndrome de West, con las manifestaciones clínicas evidenciadas en una paciente; ya que es una patología poco frecuente en nuestro medio y es importante conocer sus características al momento de realizar el diagnóstico y su respectivo tratamiento...

West syndrome is a type of epilepsy that occurs mainly in early age, is characterized by the classic triad of epileptic spasms, psychomotor retardation and electroencephalogram with hypsarrhythmia, although one of these elements can be absent, from the etiological point of view is classified in idiopathic, cryptogenic and symptomatic. The objective of this review is to present the most important features of the West Syndrome, with the clinical manifestations evidenced in a patient, this is rare in our area and it is important to know their characteristics at the time of diagnosis and respective treatment...

Indicaciones para marcapasos en medicina crítica / Indications for pacemacker in critical medicine

Se discuten las indicaciones tanto de marcapasos temporales como definitivos, en situaciones críticas que se encuentran dentro del campo de acción del intensivista. Marcapaso temporal en bradiarritmias sintomáticas, profilácticos en el infarto agudo del miocardio y en el "overdrive" o sobreconducción de taquiarritmias. Se sintetizan los lineamientos de la American Heart Association y el American College of Cardiology para la implantación de marcapasos permanetes y los criterios de selección del marcapaso ideal en cada situación clínica. Se analizan los permanentes para el manejo de taquiarritmias