Henk E. D. J. ter Keurs

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The purpose of this study was to determine force-length relations of selected human skeletal muscles, based on the theoretical foundations of the cross-bridge model and to calculate a strength curve for knee extension from these relations. Force-length relations were determined for the rectus femoris, vastus lateralis, vastus medialis, vastus intermedius(More)
Purkinje (P)-fibres are cardiac myocytes that are specialized for fast conduction of the electrical signal. P-fibres are usually defined as having the following identifying features: lack of T tubules; frequent lateral cell junctions; deep indentations at the intercalated discs level; the CX40 isoforms of gap junction proteins and, in large mammals, paucity(More)
In this paper the force-length relation of intact, in vivo, human rectus femoris musles were determined experimentally and compared to a corresponding theoretical force-length relation based on the cross-bridge theory. The experimental force-length relation has a much smaller peak force and a much wider range of muscle fiber lengths where non-zero forces(More)
The study tests the hypothesis that the transition rate (G) of the cardiac cross-bridge (XB) from the strong force generating state to the weak state is a linear function of the sarcomere shortening velocity $$\left( {V_{{\text{SL}}} } \right)$$ . Force (F) was measured with a strain gauge in six trabeculae from the rat right ventricle in K-H solution(More)
The macroscopic hallmarks of the normal heartbeat are rapid onset of contraction and rapid relaxation and an inotropic response to both increased end diastolic volume and increased heart rate. At the microscopic level, the calcium ion (Ca2+) plays a crucial role in normal cardiac contraction. This paper reviews the cycle of Ca2+ fluxes during the normal(More)
In this paper a method is presented to determine force-length relations of in-vivo human skeletal muscles. The method is experimental and can be used for selected multi-joint muscles. It contains three basic assumptions: (a) the maximal, isometric force a muscle can exert is constant for a given muscle length, (b) antagonistic muscle activity for the(More)
Peak force and membrane potential were recorded from papillary muscles and trabeculae excised from the ventricles of adult rat hearts. Experiments were performed at 2.5 mM Ca2+ and 26°C. In thick preparations (diameter 0.2–1.2 mm) an increase of stimulation frequency caused a reduction of peak force and action potential duration as has been found in many(More)
Impedance cardiography has not achieved popularity in the Intensive Care Unit (ICU) to date probably because of the limitations in technique and interpretation associated with the altered physiology of critically ill patients, and also because of interference from other machinery in the ICU. The current climate of questioning the existing technology for(More)
A classical paper published by Michael Barany almost 50 years ago demonstrated a tight correlation between the mechanical parameter of maximal velocity of shortening and the biochemical parameter of myosin ATPase activity in a wide spectrum of species. Here, we review the determinants of muscle dynamics by mechanical load and the relation between sarcomere(More)