Microarrays were utilized to determine gene expression of vascular endothelial cells (ECs) subjected to mechanical stretch for insight into the role of strain in vascular pathophysiology. Over 4,000 genes were screened for expression changes resulting from cyclic strain (10%, 1 Hz) of human umbilical vein ECs for 6 and 24 h. Comparison of t-statistics and adjusted P values identified genes havi...

Injection into the arterial supply of skeletal muscle of pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), a P2 receptor antagonist, has been shown previously to attenuate the reflex pressor responses to both static contraction and to tendon stretch. In decerebrated cats, we tested the hypothesis that PPADS attenuated the responses of groups III and IV muscle afferents to static co...

Neural stem and progenitor cell (NSPC) fate is strongly influenced by mechanotransduction as modulation of substrate stiffness affects lineage choice. Other types of mechanical stimuli, such as stretch (tensile strain), occur during CNS development and trauma, but their consequences for NSPC differentiation have not been reported. We delivered a 10% static equibiaxial stretch to NSPCs and exami...

Mechanical force can induce a number of fundamental short- and long-term responses in myocardium. These include alterations in ECM, activation of cell-signaling pathways, altered gene regulation, changes in cell proliferation and growth, and secretion of a number of peptides and growth factors. It is now known that a number of these autocrine/paracrine factors are secreted from both cardiomyocy...

The measurement of ventricular diastolic compliance is complicated by the presence of viscous properties. To approach this problem, cat papillary muscles contracting isometrically at 15/min at 26 degrees C were stretched at different velocities during diastole. At a given length there was no excess of force above that defined by the static force-length curve until velocity of stretch exceeded 1...

Introduction: Traditionally, static passive stretching has been used by coaches and athletes as a warm-up technique in an attempt to promote better performances. However, the results of recent research have shown that passive muscle stretching can diminish the peak force output of subsequent maximal concentric contractions of the quadriceps. Aside from clinicians’ benefits, athletes competing i...

We tested the hypothesis that static contraction causes greater reflex cardiovascular responses than dynamic contraction at equivalent workloads [i.e., same tension-time index (TTI), holding either contraction time or peak tension constant] in chloralose-anesthetized cats. When time was held constant and tension was allowed to vary, dynamic contraction of the hindlimb muscles evoked greater inc...

The reasons for bacterial proliferation in the lungs of mechanically ventilated patients are poorly understood. We hypothesized that prolonged cyclic stretch of lung cells influenced bacterial growth. Human alveolar type II-like A549 cells were submitted in vitro to prolonged cyclic stretch. Bacteria were cultured in conditioned supernatants from cells submitted to stretch and from control stat...

The finding that pyridoxalphosphate-6-azophenyl-2,4-disulfonic acid (PPADS), a P2 antagonist, attenuated the pressor response to calcaneal tendon stretch, a purely mechanical stimulus, raises the possibility that P2 receptors sensitize mechanoreceptors to static contraction of the triceps surae muscles. The mechanical component of the exercise pressor reflex, which is evoked by static contracti...

Cortical control of the sensory output of muscle spindles was studied in thirteen anesthetized cats in the present experiment. Gamma motoneuron activity was monitored during electrical stimulation of the sensorimotor cortex while recording from single primary afferents from the tenuissimus muscle. Findings are as follows: 1. The state of anesthesia is crucial in obtaining reproducible resu...