Analysis of skeletal muscle gene expression patterns and the impact of functional capacity in patients with systolic heart failure.

Background: Declining physical function is common among systolic heart failure (HF) patients and heralds poor clinical outcomes. We hypothesized that coordinated shifts in expression of ubiquitin-mediated atrophy-promoting genes are associated with muscle atrophy and contribute to decreased physical function.

Methods: Systolic HF patients (left ventricular ejection fraction [LVEF] ≤40%) underwent skeletal muscle biopsies (nondominant vastus lateralis) and comprehensive physical assessments.

Hepatic-specific accessibility of Igf1 gene enhancers is independent of growth hormone signaling.

The diverse roles of IGF-1 in physiology include acting as the endocrine intermediate to elicit the anabolic actions of GH. The majority of serum IGF-1 is synthesized in liver, where GH stimulates Igf1 gene transcription via the transcription factor, signal transducer and activator of transcription (Stat)5b. We and others have identified multiple Stat5-binding domains at the Igf1 locus that function in gene regulation, but it remains unclear whether the roles of these domains are tissue specific.

Natural variation in Drosophila stressed locomotion meets or exceeds variation caused by hsp70 mutation: analysis of behavior and performance.

Thermotolerance involves more than life or death. Investigating the complexity of this trait will aid identification of its genetic contributors. We examined variation in thermally stressed walking behavior and performance in natural Drosophila melanogaster strains and strains mutant for the heat shock protein Hsp70, to determine which aspects of locomotion are affected by heat shock and genotype.