Decentralized control with input saturation: a first step toward design

This article summarizes important observations about control of decentralized systems with input saturation and provides a few examples that give insight into the structure of such systems

Irisin evokes bradycardia by activating cardiac-projecting neurons of nucleus ambiguus.

Irisin is a newly identified hormone induced in muscle and adipose tissues by physical activity. This protein and its encoding gene have been identified in the brain; in addition, the precursor for irisin, FNDC5, can cross the blood-brain barrier. The fact that irisin is secreted during exercise together with the lower resting heart rate in athletes prompted us to investigate the effect of irisin on cardiac-projecting vagal neurons of nucleus ambiguus, a key regulatory site of heart rate. In vitro experiments in cultured nucleus ambiguus neurons indicate that irisin activates these neurons, inducing an increase in cytosolic Ca(2+) concentration and neuronal depolarization. In vivo microinjection of irisin into the nucleus ambiguus promotes bradycardia in conscious rats. Our study is the first to report the effects of irisin on the neurons controlling the cardiac vagal tone and to link a myokine to a cardioprotective role, by modulating central cardiovascular regulation

Nesfatin-1 activates cardiac vagal neurons of nucleus ambiguus and elicits bradycardia in conscious rats.

Nesfatin-1, a peptide whose receptor is yet to be identified, has been involved in the modulation of feeding, stress, and metabolic responses. More recently, increasing evidence supports a modulatory role for nesfatin-1 in autonomic and cardiovascular activity. This study was undertaken to test if the expression of nesfatin-1 in the nucleus ambiguus, a key site for parasympathetic cardiac control, may be correlated with a functional role. As we have previously demonstrated that nesfatin-1 elicits Ca²⁺ signaling in hypothalamic neurons, we first assessed the effect of this peptide on cytosolic Ca²⁺ in cardiac pre-ganglionic neurons of nucleus ambiguus. We provide evidence that nesfatin-1 increases cytosolic Ca²⁺ concentration via a Gi/o-coupled mechanism. The nesfatin-1-induced Ca²⁺ rise is critically dependent on Ca²⁺ influx via P/Q-type voltage-activated Ca²⁺ channels. Repeated administration of nesfatin-1 leads to tachyphylaxis. Furthermore, nesfatin-1 produces a dose-dependent depolarization of cardiac vagal neurons via a Gi/o-coupled mechanism. In vivo studies, using telemetric and tail-cuff monitoring of heart rate and blood pressure, indicate that microinjection of nesfatin-1 into the nucleus ambiguus produces bradycardia not accompanied by a change in blood pressure in conscious rats. Taken together, our results identify for the first time that nesfatin-1 decreases heart rate by activating cardiac vagal neurons of nucleus ambiguus. Our results indicate that nesfatin-1, one of the most potent feeding peptides, increases cytosolic Ca²⁺ by promoting Ca²⁺ influx via P/Q channels and depolarizes nucleus ambiguus neurons; both effects are Gi/o-mediated. In vivo studies indicate that microinjection of nesfatin-1 into nucleus ambiguus produces bradycardia in conscious rats. This is the first report that nesfatin-1 increases the parasympathetic cardiac tone

Asthma Phenotypes in Childhood

INTRODUCTION: Asthma is no longer thought of as a single disease, but rather a collection of varying symptoms expressing different disease patterns. One of the ongoing challenges is understanding the underlying pathophysiological mechanisms that may be responsible for the varying responses to treatment. Areas Covered: This review provides an overview of our current understanding of the asthma phenotype concept in childhood and describes key findings from both conventional and data-driven methods. Expert Commentary: With the vast amounts of data generated from cohorts, there is hope that we can elucidate distinct pathophysiological mechanisms, or endotypes. In return, this would lead to better patient stratification and disease management, thereby providing true personalised medicine

Carnitine palmitoyl transferase type 2 defi ciency -case report and review of the literature

ABSTRACT -Carnitine palmitoyl transferase (CPT) defi ciency is a relatively rare disease of fatty acid oxidation inherited autosomal recessively. CPT2 defi ciency presents frequently in adults with rhabdomyolysis and myoglobinuria triggered most oft en by prolonged exercise. Carnitine is required for the transfer of longchain fatty acids from the cytoplasm to the mitochondrial matrix for their oxidation. Strenuous exercise is known to increase serum creatine kinase (CK) in nearly all healthy people and can be elevated oft en over ten times the upper limit of normal. Rhabdomyolysis can be of inherited etiology (disorders of glycogenolysis, fatty acid oxidation, mitochondrial respiratory chain pathways) or acquired (trauma, compartment syndrome, drugs, caff eine, toxins, infections, infl ammatory muscle diseases, and exertion). Here we present a female patient with CPT2 defi ciency diagnosed aft er recurrent rhabdomyolysis upon physical exertion and carbohydrate-restrictive diet. With the implementation of dietary measures and lifestyle changes that included more frequent but shorter interval exercise and avoidance of inappropriate physical exertion, the patient had a normal neurological status with only slightly elevated CK levels. Th is example illustrates the importance of careful monitoring of patients with increased levels of CK, even when there are no evident clinical, histopathologic or electromyoneurography (EMNG) indicators of myopathy

Testing Logselfsimilarity of Soil Particle Size Distribution: Simulation with Minimum Inputs

Particle size distribution (PSD) greatly influences other soil physical properties. A detailed textural analysis is time-consuming and expensive. Soil texture is commonly reported in terms of mass percentages of a small number of size fractions (typically, clay, silt and sand). A method to simulate the PSD from such a poor description or even from the poorest description, consisting in the mass percentages of only two soil size fractions, would be extremly useful for prediction purposes. The goal of this paper is to simulate soil PSDs from the minimum number of inputs, i.e., two and three textural fraction contents, by using a logselfsimilar model and an iterated function system constructed with these data. High quality data on 171 soils are used. Additionally, the characterization of soil texture by entropy-based parameters provided by the model is tested. Results indicate that the logselfsimilar model may be a useful tool to simulate PSD for the construction of pedotransfer functions related to other soil properties when textural information is limited to moderate textural data