The aim of this study was to evaluate how fish locomote at different muscle temperatures. Sarcomere length excursion and muscle shortening velocity, V, were determined from high-speed motion pictures of carp, Cyprinus carpio (11-14 cm), swimming steadily at various sustained speeds at 10, 15 and 20 degrees C. In the middle and posterior regions of the carp, sarcomeres of the lateral red muscle ...

The hydrolysis of adenosine 3':5'-monophosphate by the high Km cyclic nucleotide phosphodiesterase of bakers' yeast was studied over a range of temperature and pH at I = 0.17. The effects of ionic strength and MgCl2 concentration were studied at pH 7.7 and 30 degrees C. Km and Vmax were insensitive to changes in the MgCl2 concentration between 1 and 30 mM, implying that this enzyme (which does ...

OBJECTIVE To determine whether there is a familial abnormality in erythrocyte Na/Li countertransport (CT) kinetics in the approximate one-third of type 1 diabetic patients that succumb to a familial predisposition to nephropathy. RESEARCH DESIGN AND METHODS Erythrocyte Na/Li CT kinetics were measured in nondiabetic first-degree relatives of type 1 diabetic patients with nephropathy (DNrel) (n...

The mechanism and substrate specificity of the phosphotriesterase from Pseudomonas diminuta have been examined. The enzyme hydrolyzes a large number of phosphotriester substrates in addition to paraoxon (diethyl p-nitrophenyl phosphate) and its thiophosphate analogue, parathion. The two ethyl groups in paraoxon can be changed to propyl and butyl groups, but the maximal velocity and Km values de...

We show that the Euclidean value of < V/Vmax > for gamma-ray bursts (GRB) selected on a timescale of 1024 ms is correlated with spectral hardness. The value of < V/Vmax > ranges from ∼ 0.42 for soft bursts to ∼ 0.26 for the hardest bursts. Given that the Euclidean value of< V/Vmax > for cosmological objects in a well defined sample is a distance indicator, the hard bursts must reside at larger ...

In this study we suggest that the velocity of water entering the cervical esophagus can be used as an index of pharyngeal swallowing function. In this article, the basic in vitro principles of water and viscous water flow velocity evaluation using ultrasonic methods are introduced. Water flow involving small gas bubbles passing through a silicon tube could be monitored in the B-mode images and ...

OBJECTIVE The aim of this study was to analyze whether cells with long action potential duration, fast Vmax, and spike-and-dome configuration (M-cells) are present in porcine left ventricular myocardium. METHODS Transmembrane action potentials (n = 505) of the left ventricle were recorded with conventional glass microelectrodes in an epicardial-endocardial direction at 2000 ms basic cycle len...

1. In intact skeletal muscle fibres, estimates of unloaded shortening velocity obtained from slack test measurements (V0) have been shown to exceed, by approximately 7%, estimates obtained from extrapolation of velocities measured during isotonic releases (Vmax). In contrast, published values for the V0 of whole soleus muscles of rats exceed Vmax by 56%. In the present study, we tested the hypo...

PURPOSE To compare pulmonary artery flow using Cartesian and radially sampled four-dimensional flow-sensitive (4D flow) MRI at two institutions. METHODS Nineteen healthy subjects and 17 pulmonary arterial hypertension (PAH) subjects underwent a Cartesian 4D flow acquisition (institution 1) or a three-dimensional radial acquisition (institution 2). The diameter, peak systolic velocity (Vmax), ...

In previous studies (Xu, A., Hawkins, C., and Narayanan, N. (1993) J. Biol. Chem. 268, 8394-8397), the Ca(2+)-ATPase of cardiac muscle sarcoplasmic reticulum (SERCA2) was shown to be phosphorylated by Ca2+/calmodulin-dependent protein kinase II (CaM kinase) on a serine residue, likely to be either Ser38, Ser167, or Ser531. SERCA2 and SERCA2 mutants S38A, S167A, and S531A were expressed in HEK-2...