Narrow Results

The present study aims to analyze the elemental distribution in erythrocytes from five hemodialysis patients treated with erythropoietin in comparison to four healthy controls. Using in-air micro-PIXE we determined that iron dots were distributed in the peripheral region of control erythrocytes, which were made up of two to four compartments. Iron dots tend to aggregate partially in hemodialysis patients. Calcium was rendered to form small dense nodules in erythrocytes of controls, and small dense nodules became marked in some hemodialysis patients. Nodular formation of phosphorous was weakened in both control and hemodialysis patients. Potassium aggregated focally and formed small dense granules in erythrocytes of healthy controls. On the other hand, hemodialysis patients showed enrichment of potassium, with diffuse spreading partially to all over erythrocytes. These findings indicate that in-air micro-PIXE is a useful tool for analyzing the elemental distributions in erythrocytes of hemodialysis patients.

Based on a comprehensive mathematical model of the energy and redox metabolism of human erythrocytes we calculated stationary metabolic states of the cell varying the activity of the participating enzymes by several orders of magnitude. To compare the computational results with clinical and experimental data reported for various enzymopathies of the red cell, the three essential metabolic variables ATP, GSH and osmolarity were included in a “homeostasis function” which allows us to estimate the range of enzyme activities in which the metabolic alterations should be either tolerable, associated with non-chronic or chronic hemolytic diseases, or letal.

A mathematical model for the drug delivery to macrophages of the tissues by using a preassigned cohort of red blood cells loaded with a drug is presented. This model is a system of three nonlinear differential equations, with a discrete time delay and an input depending on the time. The input should be controlled in order to obtain the longest duration of the therapeutic effect.

We report a novel method to simultaneously extract superoxide dismutase (SOD), catalase (CAT) and carbonic anhydrase (CA) from the same sample of red blood cells (RBCs). This avoids the need to use expensive commercial enzymes, thus allowing this to be cost effective for large-scale production of a nanobiotechnological polyHb-SOD-CAT-CA with enhancements to all three RBC functions. The best concentration of phosphate buffer for ethanol-chloroform treatment results in good recovery of CAT, SOD and CA after extraction. Different concentrations of the enzymes can be used to enhance the activity of polyHb-SOD-CAT-CA to 2, 4 or 6 times that of RBCs.

Copper and mercury play a toxic role in several pathological processes, including neurodegeneration. The structural effects of Cu²⁺ and Hg²⁺ on cell membranes were studied through their interactions with human erythrocytes, isolated resealed membranes, and molecular models. Both ions induced shape changes in erythrocytes, which took the form of echinocytes due to location of the ions in the outer monolayer of the erythrocyte membrane. Fluorescence spectroscopy analysis revealed that the interactions occurred in the polar region of me membrane, that is, at the hydrophobic-hydrophilic interface. X-ray experiments indicated that both ions interacted with the polar groups of phospholipids located in the outer monolayer of the erythrocyte membrane. Finally, electrophysiological measurements of toad skin showed that Cu²⁺ and Hg²⁺ inhibited the active transport of ions. The experimental results confirmed the toxicity of both heavy metals on membrane structure and functions.