We hypothesized that unilateral denervation (DNV) of the rat diaphragm muscle (Dia(m)) in neonates at postnatal day 7 (D-7) alters normal transitions of myosin heavy chain (MHC) isoform expression and thereby affects postnatal changes in maximum specific force (P(o)) and maximum unloaded shortening velocity (V(o)). The relative expression of different MHC isoforms was analyzed electrophoretical...

The present study examined Ca(2+) sensitivity of diaphragm muscle (Dia(m)) fibers expressing different myosin heavy chain (MHC) isoforms. We hypothesized that Dia(m) fibers expressing the MHC(slow) isoform have greater Ca(2+) sensitivity than fibers expressing fast MHC isoforms and that this fiber-type difference in Ca(2+) sensitivity reflects the isoform composition of the troponin (Tn) comple...

The Drosophila wing is covered by an array of distally pointing hairs that has served as a key model system for studying planar cell polarity (PCP). The adult cuticular hairs are formed in the pupae from cell extensions that contain extensive actin filaments and microtubules. The importance of the actin cytoskeleton for hair growth and morphogenesis is clear from the wide range of phenotypes se...

The effect of chronic exogenous testosterone (T) treatment on neuromuscular transmission in the diaphragm (Dia) muscle of adult male rats was determined. The contribution of neuromuscular transmission failure (NTF) to Dia fatigue was evaluated by superimposing intermittent direct muscle stimulation on repetitive nerve stimulation of isometric contraction in vitro. T treatment significantly redu...

It is controversial whether insulin-like growth factor I (IGF-I), growth hormone (GH), or their combination might enhance body growth and/or tissue anabolism in the well-fed animal with an intact somatotrophic axis. To assess this further, we studied four groups of adolescent rats: 1) control (Ctr), 2) GH, 3) IGF-I, and 4) GH/IGF-I. IGF-I was given via an osmotic minipump, whereas GH was inject...

During migration cell protrusions power cell extension and sample the environment. Different cells produce different protrusions, from keratocytes dominated by lamellipodia, to growth cones combining filopodia and lamellipodia, to dendritic spines. One key challenge is to determine how the toolkit of actin regulators are coordinated to generate these diverse protrusive arrays. Here we use Droso...

The impact of hypothyroidism (Hyp) on myosin heavy chain (MHC) isoform expression, maximum specific force (P0), fatigability, and maximum unloaded shortening velocity (V0) was determined in the rat diaphragm muscle (Dia) at 0, 7, 14, 21, and 28 days of age. Hyp was induced by treating pregnant rats with 6-n-propyl-2-thiouracil (0.05% in drinking water) beginning at gestational day 10 and was co...

Tumor necrosis factor (TNF)-α, has been implicated in several muscle wasting disorders with increased levels of the cytokine reported in malnourished children. The role of TNF-α in mediating malnutrition-induced inhibition of diaphragm (DIA) muscle growth in young growing rats was evaluated. Three groups of rats were studied: 1) Control (CTL); 2) Nutritional deprivation (ND; 50% of normal food ...