Alterations in lung gene expression in streptozotocin-induced diabetic rats.

Background: Diabetes profoundly affects gene expression in organs such as heart, skeletal muscle, kidney and liver, with areas of perturbation including carbohydrate and lipid metabolism, oxidative stress, and protein ubiquitination. Type 1 diabetes impairs lung function, but whether gene expression alterations in the lung parallel those of other tissue types is largely unexplored.

Methods: Lung from a rat model of diabetes mellitus induced by streptozotocin was subjected to gene expression microarray analysis.

Fatigue-inducing stimulation resolves myotonia in a drug-induced model.

Background: Slowed muscle relaxation is the contractile hallmark of myotonia congenita, a disease caused by genetic CLC-1 chloride channel deficiency, which improves with antecedent brief contractions ("warm-up phenomenon"). It is unclear to what extent the myotonia continues to dissipate during continued repetitive contractions and how this relates temporally to muscle fatigue. Diaphragm, EDL, and soleus muscles were examined in vitro during repetitive 20 Hz and 50 Hz train stimulation in a drug-induced (9-AC) rat myotonia model.

Differential expression of lipid and carbohydrate metabolism genes in upper airway versus diaphragm muscle.

Study Objectives: Contractile properties of upper airway muscles influence upper airway patency, an issue of particular importance for subjects with obstructive sleep apnea. Expression of genes related to cellular energetics is, in turn, critical for the maintenance of contractile integrity over time during repetitive activation. We tested the hypothesis that sternohyoid has lower expression of genes related to lipid and carbohydrate energetic pathways than the diaphragm.

Contrast between cardiac left ventricle and diaphragm muscle in expression of genes involved in carbohydrate and lipid metabolism.

The heart and diaphragm both need appropriate metabolic machinery to ensure long-term energy supplies, as they must contract rhythmically without cessation for the entire lifetime of the organism to ensure homeostasis of oxygen and carbon dioxide exchange. However, their energy requirements differ due to disparities in mechanical loads. Understanding how these two muscles converge and diverge in their approaches to meeting their metabolic demands may suggest novel strategies for improving cardiac and skeletal muscle long-term performance in health and disease.