1.
Hormonal and Metabolic Responses to a Single Bout of Resistance Exercise in Prader-Willi Syndrome
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Rubin, DA, Clark, SJ, Haqq, AM, Castner, DM, Ng, J, Judelson, DA
Hormone research in paediatrics. 2017;(3):153-161
Abstract
BACKGROUND Prader-Willi syndrome (PWS) is characterized by excessive adiposity. Excess adiposity negatively affects hormonal and metabolic responses to aerobic exercise. This study determined whether PWS and/or adiposity affected hormonal and metabolic responses to resistance exercise. METHODS Eleven children with PWS (11.4 ± 3.1 years, 43.9 ± 7.5% body fat), 12 lean children (9.3 ± 1.4 years, 18.3 ± 4.9% body fat), and 13 obese children (9.6 ± 1.3 years, 40.3 ± 5.2% body fat) participated. The children stepped onto an elevated platform while wearing a weighted vest for 6 sets of 10 repetitions per leg (sets separated by 1 min of rest). For the children with PWS, the platform height was 23.0 cm and vest load was computed as (20% of stature × 50% of lean body mass)/23.0 cm. For the controls, the platform height was 20% of the stature and vest load 50% of the lean body mass. Blood samples were obtained before, immediately after, and during recovery from exercise (+15, +30, and +60 min). RESULTS All groups had similar catecholamine, insulin, and glucagon responses. The groups showed no major differences in glucose and lactate levels. The PWS children demonstrated earlier increases in fatty acids during recovery and higher glycerol and ketone levels than the controls. CONCLUSION The PWS children demonstrated largely intact hormonal, glycolytic, and lipolytic responses to lower-body resistance exercise. In PWS, elevated ketone levels suggest an incomplete fat oxidation.
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2.
Clinical features and pharmacotherapy of childhood monoamine neurotransmitter disorders.
Ng, J, Heales, SJ, Kurian, MA
Paediatric drugs. 2014;(4):275-91
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Abstract
Childhood neurotransmitter disorders are increasingly recognised as an expanding group of inherited neurometabolic syndromes. They are caused by disturbance in synthesis, metabolism, and homeostasis of the monoamine neurotransmitters, including the catecholamines (dopamine, norepinephrine, and epinephrine) and serotonin. Disturbances in monoamine neurotransmission will lead to neurological symptoms that often overlap with clinical features of other childhood neurological disorders (such as hypoxic ischaemic encephalopathy, cerebral palsy, other movement disorders, and paroxysmal conditions); consequently, neurotransmitter disorders are frequently misdiagnosed. The diagnosis of neurotransmitter disorders is made through detailed clinical assessment, analysis of cerebrospinal fluid neurotransmitters, and further supportive diagnostic investigations. Early and accurate diagnosis of neurotransmitter disorders is important, as many are amenable to therapeutic intervention. The principles of treatment for monoamine neurotransmitter disorders are mainly directly derived from understanding these metabolic pathways. In disorders characterized by enzyme deficiency, we aim to increase monoamine substrate availability, boost enzyme co-factor levels, reduce monoamine breakdown, and replace depleted levels of monoamines with pharmacological analogs as clinically indicated. Most monoamine neurotransmitter disorders lead to reduced levels of central dopamine and/or serotonin. Complete amelioration of motor symptoms is achievable in some disorders, such as Segawa's syndrome, and, in other conditions, significant improvement in quality of life can be attained with pharmacotherapy. In this review, we provide an overview of the clinical features and current treatment strategies for childhood monoamine neurotransmitter disorders.
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Exercise-induced ventricular arrhythmias in patients with no structural cardiac disease.
Scheinman, MM, Lam, J
Annual review of medicine. 2006;:473-84
Abstract
We review the clinical and genetic disorders associated with exercise-induced ventricular arrhythmias in patients with normal hearts. Foremost are those with catecholaminergic polymorphic ventricular tachycardia due to abnormalities in either the ryanodine receptor 2 genes (RyR2) or the calsequestrin genes (CASQ). These patients manifest ventricular premature beats and polymorphic ventricular tachycardia in response to exercise or on exposure to catecholamines. A great deal of basic information has been accumulated suggesting that these arrhythmias are caused by abnormalities in Ca2+ metabolism. The ensuing cytosolic Ca2+ overload results in delayed after-depolarizations and extrasystolic Ca2+ waves, leading to polymorphic ventricular tachycardia. Most of these patients will respond to beta-blocker therapy but a significant minority (30%) will require a defibrillator. Advances in genetic testing allow better understanding of this syndrome.