Ca(2+)-Mg (2+)-dependent ATP-ase activity in hemodialyzed children. Effect of a hemodialysis session.

In the course of chronic kidney disease (CKD) the intracellular erythrocyte calcium (Ca (i) (2+) ) level increases along with the progression of the disease. The decreased activity of Ca(2+)-Mg(2+)-dependent ATP-ase (PMCA) and its endogenous modulators calmodulin (CALM), calpain (CANP), and calpastatin (CAST) are all responsible for disturbed calcium metabolism. The aim of the study was to analyze the activity of PMCA, CALM, and the CANP-CAST system in the red blood cells (RBCs) of hemodialyzed (HD) children and to estimate the impact of a single HD session on the aforementioned disturbances.

The endogenous modulators of Ca2+-Mg2+-dependent ATPase in children with chronic kidney disease (CKD).

Background: Calcium homeostasis is disturbed in many ways in the course of chronic kidney disease (CKD). The concentration of free cytoplasmic calcium in erythrocytes is increased. Maintenance of a high concentration gradient (between the cystoplasmic and extracellular space) is possible only due to a finely tuned cooperation between many regulating systems in the cytoplasmic membranes and cell organelles.

Usefulness of body surface potential mapping for early identification of the intraventricular conduction disorders in young patients with chronic kidney disease.

Background: Cardiovascular complications are considered a significant problem in patients with chronic kidney disease (CKD). Body surface potential mapping (BSPM) is a noninvasive method that is useful in detecting early changes involving the heart. The aim of the study was to evaluate possible abnormalities within the cardiac intraventricular conduction system in young patients with CKD using the BSPM method.

Ca2+-Mg2+-dependent ATP-ase activity and calcium homeostasis in children with chronic kidney disease.

Extracellular calcium concentrations in humans are thousands times higher than within cells. Maintenance of such gradient requires specific regulation including intracellular stores, Ca binding proteins and transmembrane protein systems. The aim of the study was to estimate PMCA (plasma membrane Ca-transporting adenosine triphosphatase; ATPase 3.

[Calpain-calpastatin system in erythrocytes of children with chronic renal failure].

Introduction: Disturbances of erythrocyte calcium homeostasis in the course of chronic renal failure (CRF) may result from impaired function of a membrane calcium pump (PMCA). Plasma membrane Ca+2-transport ATP-ase is responsible for maintaining cytoplasmic level of intracellular Ca+2. PMCA activity is regulated by high Ca levels and calmodulin, in case of Ca+2 deficiency--by intracellular cysteine protease--calpain, and its natural inhibitor--calpastatin.

Influence of diethyldithiocarbamate on the activity of ecto-ATPase in lymphocytes of rats: ex vivo studies.

Influence of diethyldithiocarbamate (DTC) on the activity of ecto-ATPase (plasma membrane-bound enzyme participating in a cascade of reactions leading to the formation of adenosine--a modulator of inflammation) was examined on the lymphocytes isolated from the spleen of rats with inflammation. DTC was administered at doses of 4 mg/kg and 290 mg/kg using two modes of administration. It has been observed that: a) an inflammation caused an increase in ecto-ATPase activity in both subpopulations of lymphocytes; in the case of B-lymphocytes, the maximum of activity occurred 48 h and in the case of T-lymophocytes, 72 h after the injection of carrageenin; b) a single injection of DTC at both doses, 24 h before or 24 h after carrageenin injection caused a decrease in ecto-ATPase activity in B-lymphocytes and its increase in T-lymphocytes throughout the whole measurement period, which was not observed when DTG was administered only after provocation of inflammation; c) administration of a high dose of DTC together with equimolar doses of disulfiram and CS2 led to a decrease in ecto-ATPase activity and 5 '-nucleotidase level in B-lymphocytes, which is bound to the former enzyme; d) in in vitro studies, both populations of lymphocytes isolated from the rats treated with a four-fold dose of DTC showed higher resistance of ecto-ATPase to inhibitors of the enzyme and antagonists of type P2 purinoceptors.