Cardiac hypertrophy in hypertensive subjects, its biochemical markers, and functional consequences are of great clinical importance but still unclear. We observed a shift of the ventricular isomyosin of adult spontaneously hypertensive (H) rats of both sexes to the V3 form and a decreased myofibrillar ATPase activity in the H animals when compared to normotensive (N) controls. Compared to the m...

To determine whether a defect in the T cell response to adenosine exists at the level of the adenosine receptor in systemic lupus erythematosus (SLE) we measured the binding affinity and maximum binding of T cell membranes from both normal and SLE T cells by utilizing radiolabeled adenosine ligands. Normal T lymphocyte membranes possess a single class of [3H]5-N-ethylcarboxamide adenosine bindi...

The interaction of Na and H ions with the extracellular and intracellular sites of the Na+/H+ exchanger of the osteosarcoma cell line UMR-106 was investigated. Na ions interact with a single, saturable extracellular transport site. H+ and amiloride appear to compete with Na+ for binding to this site. The apparent affinity for extracellular Na+ (Nao+) and amiloride was independent of intracellul...

The distribution and kinetic properties of guanylate cyclase in normal. denervated and dystrophic muscle from lower hind limb muscle of rat and mouse were studied. Approximately 75% of the enzyme activity was in a high speed supernatant fraction (100,000 x g) and 15 to 20% in a particulate fraction (1.000 x g pellet). The particulate guanylate cyclase was found highly enriched in sarcolemma, in...

Quercetin is a substance of low molecular weight found in vascular plants with a wide range of biological activities including antioxidative and anti-inflammatory activities. In the present study, the effects of quercetin on native glycine receptors (GlyRs) in cultured rat hippocampal neurons were investigated using a whole-cell patch-clamp technique. Quercetin reversibly and concentration-depe...

Hepatitis C virus (HCV) shows a great geographical diversity reflected in the high number of circulating genotypes and subtypes. The response to HCV treatment is genotype specific, with the predominant genotype 1 showing the lowest rate of sustained virological response. Virally encoded enzymes are candidate targets for intervention. In particular, promising antiviral molecules are being develo...

Lymphatic muscle contraction is critical for the centripetal movement of lymph that regulates fluid balance, protein homeostasis, lipid absorption, and immune function. We have demonstrated that lymphatic muscle has both smooth and striated muscle contractile elements; however, the basic contractile properties of this tissue remain poorly defined. We hypothesized that contractile characteristic...

Several mammalian cytochrome P450 (P450) isoforms demonstrate homotropic cooperativity with a number of substrates, including steroids and polycyclic aromatic hydrocarbons. To identify structural factors contributing to steroid and polycyclic aromatic hydrocarbon binding to P450 enzymes and to determine the location of the allosteric site, we investigated interactions of the macrolide hydroxyla...

The voltage dependence of the rat renal type II Na+/Pi cotransporter (NaPi-2) was investigated by expressing NaPi-2 in Xenopus laevis oocytes and applying the two-electrode voltage clamp. In the steady state, superfusion with inorganic phosphate (Pi) induced inward currents (Ip) in the presence of 96 mM Na+ over the potential range -140 </= V </= +40 mV. With Pi as the variable substrate, the a...

Systems biology seeks to model biological networks dynamically. Two requirements need to be fulfilled for this to be possible. First, the interaction networks need to be known. Second, the dynamics of the interactions have to be revealed. Dynamics of interactions are described by rate laws using kinetics. These kinetics describe the interaction mechanism. For each single interaction occurring i...