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To describe the clinical and molecular characteristics of patients with childhood-onset Stargardt disease (STGD).Retrospective case series.Forty-two patients who were diagnosed with STGD in childhood at a single institution between January 2001 and January

Aims: Impaired energy metabolism has been implicated in the pathogenesis of heart failure. Hyperpolarized (13)C magnetic resonance (MR), in which (13)C-labelled metabolites are followed using MR imaging (MRI) or spectroscopy (MRS), has enabled non-invasive assessment of pyruvate metabolism. We investigated the hypothesis that if we serially examined a model of heart failure using non-invasive hyperpolarized [(13)C]pyruvate with MR, the profile of in vivo pyruvate oxidation would change throughout the course of the disease.Methods and Results: Dilated cardiomyopathy (DCM) was induced in pigs (n = 5) by rapid pacing. Pigs were examined using MR at weekly time points: cine-MRI assessed cardiac structure and function; hyperpolarized [2-(13)C]pyruvate was administered intravenously, and (13)C MRS monitored [(13)C]glutamate production; (31)P MRS assessed cardiac energetics [phosphocreatine (PCr)/ATP]; and hyperpolarized [1-(13)C]pyruvate was administered for MRI of pyruvate dehydrogenase complex (PDC)-mediated pyruvate oxidation via [(13)C]bicarbonate production. Early in pacing, the cardiac index decreased by 25%, PCr/ATP decreased by 26%, and [(13)C]glutamate production decreased by 51%. After clinical features of DCM appeared, end-diastolic volume increased by 40% and [(13)C]bicarbonate production decreased by 67%. Pyruvate dehydrogenase kinase 4 protein increased by two-fold, and phosphorylated Akt decreased by half. Peroxisome proliferator-activated receptor-α and carnitine palmitoyltransferase-1 gene expression decreased by a half and a third, respectively.Conclusion: Despite early changes associated with cardiac energetics and (13)C incorporation into the Krebs cycle, pyruvate oxidation was maintained until DCM developed, when the heart's capacity to oxidize both pyruvate and fats was reduced. Hyperpolarized (13)C MR may be important to characterize metabolic changes that occur during heart failure progression. [ABSTRACT FROM AUTHOR]

The dipeptide carnosine has been shown to contribute to the buffer capacity of hydrogen ions (H+) during intense exercise. Increasing skeletal muscle carnosine levels through ß-alanine (BA) supplementation has been shown to maintain acid-base balance, delay fatigue, and improve exercise performance. We designed this study to examine the effect of 5 weeks of BA supplementation on repeat high-intensity sprint performance. Nineteen, physically active, college men were divided into 2 groups (control [C], n = 10 or BA, n = 9). We performed double-blind placebo-controlled study where subjects ingested 4 g per day during the first week and 6 g per day over the next 4 weeks of a placebo (rice flour) or a BA supplement. Subjects completed 2 sets of 5 5-second sprints with 45-second recovery separated by 2 minutes of active recovery. All tests were conducted on a non-motorized treadmill against a resistance of 15% of the participant's body weight. We recorded horizontal power (HP) of the running sprint. Post-exercise capillary blood samples were analyzed for lactate to determine the metabolic demands. There were no significant between-group differences (p > 0.05) in HPpeak or HPmean for the repeat sprint protocol. No significant between-group differences were found for performance decrement (% fatigue) for HPpeak or HPmean. In addition, no significant interactions were observed. Post-exercise blood lactate values were similar pre and post supplementation in both groups. The results of this study clearly indicate that 5 weeks of BA supplementation provides no benefit for repeat sprint performance. [ABSTRACT FROM AUTHOR]