The magnitude of length dependent activation in striated muscle has been shown to vary with titin isoform. Recently, a rat that harbors a homozygous autosomal mutation (HM) causing preferential expression of a longer, giant titin isoform was discovered (Greaser et al. 2005). Here, we investigated the impact of titin isoform on myofilament force development and cross-bridge cycling kinetics as f...

A balanced-force control volume finite element method is presented for three-dimensional interfacial flows with surface tension on adaptive anisotropic unstructured meshes. A new balanced-force algorithm for the continuum surface tension model on unstructured meshes is proposed within an interface capturing framework based on the volume of fluid method, which ensures that the surface tension fo...

PETERSON, JOHN W., AND RICHARD J. PAUL. Effects of initial length and active shortening on vascular smooth muscle contractility. Am. J. Physiol. 227(5) : 1019-1024. 1974.-The active isometric tension-length relation has been studied in bovine mesenteric vein at 37°C under a variety of experimental conditions, including both passive and active changes in muscle length. The rest length Lo , defin...

Single fibers, 25-40 microm wide and 0.5-0.7 mm long, were isolated from the flexor digitorum brevis muscle of the mouse. Force and movement were recorded (21-27 degrees C) from the fiber as a whole and, in certain experiments, from a short marked segment that was held at constant length by feedback control. The maximum tetanic force, 368+/-57 kN/m2 (N = 10), was not significantly different fro...

We explored the retraction or contraction of platelet-fibrin clots under isometric conditions. In the presence of micromolar calcium clots of normal platelet-rich plasma developed tension at an initial rate of 0.1 to 0.2 g/min per cm2 (initial cross-sectional area). Electron microscopy of clots fixed after attaining a force of 1.6 g/cm2 revealed platelets with elongated bodies and pseudopods in...

We previously demonstrated that diaphragm muscle weakness is present in experimental pulmonary arterial hypertension (PH). However, the nature of this diaphragm weakness is still unknown. Therefore, the aim of this study was to investigate whether changes at the sarcomeric level contribute to diaphragm weakness in PH. For this purpose, in control rats and rats with monocrotaline-induced PH, con...

The force output of the knee extensor muscles and its time course were measured in nine patients with spinocerebellar degenerations and age-matched 10 normal subjects during the fastest and strongest isometric contraction. The time from the rise of tension to its maximum, FTmax, was definitely long in the SCD compared to the normal group, whereas the peak tension was not different between the t...