High-Throughput Omics Technologies: Potential Tools for the Investigation of Influences of EMF on Biological Systems.

The mode of action of a huge amount of agents on biological systems is still unknown. One example where more questions than answers exist is covered by the term electromagnetic fields (EMF). Use of wireless communication, e.g. mobile phones, has been escalated in the last few years. Due to this fact, a lot of discussions dealt with health consequences of EMF emitted by these devices and led to an increased investigation of their effects to biological systems, mainly by using traditional methods. Omics technologies have the advantage to contain methods for investigations on DNA-, RNA- and protein level as well as changes in the metabolism.This literature survey is an overview of the available scientific publications regarding biological and health effects of EMF and the application of new high-throughput technologies. The aim of the study was to analyse the amount and the distribution of these technologies and to evaluate their relevance to the risk analysis of EMF. At present, only transcriptomics is able to analyse almost all of the specific molecules. In comparison to ionising radiation, fewer articles dealt with health effects of EMF. Interestingly, most of the EMF articles came from European institutions.Although omics techniques allow exact and simultaneous examinations of thousands of genes, proteins and metabolites in high-throughput technologies, it will be an absolute prerequisite to use standardised protocols and to independently validate the results for comparability and eventually for sound standing statements concerning possible effects of agents like EMF on biological systems.

Immunoglobulin G binding to human erythrocytes.

The binding of 125iodine labelled human IgG to allogenic erythrocytes was studied at various ratios of free IgG per cell. At low concentrations of free IgG a high affinity binding was measured, which is with respect to its apparent association constant (2.8 x 10(13) mol-1) most likely a specific receptor binding and might indicate aged cells of those destined for elimination. At higher concentrations of free IgG the erythrocytes were coated by IgG in a non-saturable manner as reported by Grob et al. (Immunology 13, 189 (1967)). The erythrocyte-bound labelled IgG, which remained in the range from 15 to 400 molecules IgG per cell after intensive washings could not be chased by unlabelled IgG. This cell-bound IgG (high affinity binding) was increased 7-fold after complete ATP-depletion of erythrocytes and was 4 times higher after erythrocyte storage for 42 days. It appears that it is not the number of bound IgG molecules alone which is important for erythrocyte recognition by macrophages but also the arrangement of IgG molecules bound to membrane polypeptides.

Enrichment of reticulocytes by lectin-mediated agglutination.

Bloods of both normal and anemic (bleeding anemia) rabbits as well as of a healthy man (blood group A1) have been treated with varying concentrations of the lectin anti-AHP. Under defined conditions, mature erythrocytes are agglutinated selectively whereas reticulocytes remain suspended as single cells in the supernatant fluid. With this procedure an enrichment of reticulocytes of about tenfold with a maximum recovery of nearly 100% was achieved.

Spreading of red blood cell suspensions on paper as a simple test of cell deformability.

Spreading of red blood cells on paper is a simple and rapid measure of erythrocyte deformability. It requires a small number of cells and is accurate enough to be applied to studies of deformability alterations caused by heat damage, metabolic depletion or storage of the cells. It is suggested as a test of red blood cell viability.

Disproportional loss of membrane constituents in the course of erythrocyte aging.

Acetylcholine esterase activity and sialic acid content were estimated in human erythrocytes separated according to their densities and after fragmentation in vitro by heating or a combined hyperosmolaric-mechanical stress. In vivo aged cells showed a disproportional loss of both membrane constituents. Fragmentation of erythrocytes in vitro resulted in a proportional loss of acetylcholine esterase activity and sialic acid. Young cells are more prone to fragmentation by heat than older ones.

[ATP-dependent and ATP-independent changes in deformability of human erythrocytes]. / ATP-abhängige und ATP-unabhängige Veränderungen der Deformierbarkeit von Humanerythrozyten.

By means of a simple filtration procedure it is shown that the deformability of red blood cells depends indirectly on their relative ATP-concentration. Losses in deformability were observed even with concentrations of ATP, which occur in the course of normal ageing of red blood cells in situ. If erythrocytes are incubated for longer times, their membrane is alterated to such a degree, that the changes cannot be reversed solely by restitution of ATP. The cells remain rigid.

The lipoxygenase of reticulocytes. Purification, characterization and biological dynamics of the lipoxygenase; its identity with the respiratory inhibitors of the reticulocyte.

A lipoxygenase has been purified from rabbit reticulocyte-rich anaemic blood cells. It possesses a molecular weight of 78 000 and an isoelectric point of 5.5 and contains 5% neutral sugars and two iron atoms per enzyme molecule. The lipoxygenase has proved to be identical with the inhibitors of respiratory proteins described formerly. The actions of the lipoxygenase on linoleic acid, phospholipids, mitochondrial and erythrocyte membranes and electron transfer particles were studied. A special feature of the reticulocyte lipoxygenase is the suicidal character of its action on lipids. With electron transfer particles the reticulocyte lipoxygenase causes a loss of acid-labile sulfur which accompanies respiratory inhibition; the strong respiratory inhibition is not exerted by soybean lipoxygenase. The reticulocyte lipoxygenase acts preferably on mitochondrial membranes as compared with cell membranes of the erythrocyte; erythrocyte cytosol moderates the action on mitochondrial membranes. Furthermore, the lipoxygenase reaction can concomitantly and irreversibly inactivate sulfhydryl enzymes as demonstrated with muscle glyceraldehyde-3-phosphate dehydrogenase. The occurrence of the lipoxygenase here described is restricted to reticulocytes; very low amounts were observed in bone marrow and no lipoxygenase was detectable in normal blood. During the course of an experimental anaemia the lipoxygenase is produced owing to superinduction in large amounts, which may persist for a long time since they escape inactivation. Preliminary evidence was obtained for the occurrence of other lipoxygenases in tissues of lung, spleen, kidney and also epithelial tumours.

[Receptors of human red blood cells for anti-TAH and anti-AHP in the course of intravascular aging]. / Rezeptoren roter Blutzellen des Menschen für Anti-TAH und Anti-AHP beim intravasalen Altern der Zellen.

Human o-erythrocytes aged in situ do not expose free receptors for anti-T agglutinin of Arachis hypogea. New receptors for concentrated anti-A agglutinin of Helix pomatia are manifested but are lost again in the course of further ageing of the cells in situ. A remasking of exposed receptors for anti-TAH and anti-AHP byautologous, strongly binding globulins is supposed. These globulins could constitute the decisive signal for the autologous phagocytosis of senescent red blood cells.

[Studies of the deformability of preserved red blood cells using a simple filtration method]. / Untersuchungen zur Verformbarkeit roter Blutzellen bei Lagerung mit einem einfachen Filtrationsverfahren.

The applied method to measure the filtrability of red blood cells is accurate enough for the study of the effects of the conditions of storage on their deformability. In this work the standard deviation of the method, the mean biological deviation of the deformability of human red blood cells and their deformability in the course of storage in the ACD-AG-medium have been investigated. Considerable loss of deformability occurs towards the end of storage time of the cells, which is not reversible be restitution of ATP alone. The applicability of this method as a simple test of the vitatity of preserved erythrocytes if to be tested.

Superoxide dismutase activity decreases during erythrocyte aging.

Superoxide dismutase activity was determined by the adrenalin method in bovine erythrocytes separated according to age. Progressive loss of the enzyme activity was found, down to ca 65% of that of the youngest cells.

[Purification and characterization of the respiratory inhibitor RF from rabbit reticulocytes]. / Reinigung und Charakterisierung des Atmungshemmstoffes RF aus Kaninchenretikulozyten.

In the stroma-free hemolysate of rabbit reticulocytes there exists a respiratory inhibitor (RF) of protein nature. It could be purified by the following procedure: (NH4)2SO4-precipitation leads to DEAE-Sephadex A-50-chromatography leads to isoelectric focusing leads to gelfiltration on Sephadex G-200. In addition to the activity the identity of the inhibitor could be proved immunologically at all steps of the purification. A molecular weight of about 80,000 was determined by gelelectrophoresis in the SDS-mercaptoethanol-system. The protein has an IP of 5.55--5.65 and consists of one polypeptide chain. This could be shown both by SDS-gelelectrophoresis and by estimation of only one N-terminal amino acid residue (glycine). Only after oxidation with performic acid the amino acid analysis of the protein gives reproducible values. The sum of weight-% is about 80 (without Tyr). The polarity of the protein with 41 mol-% agrees with the polarity of soluble globular proteins investigated by other authors. Acid hydrolysis without preceeding performic acid oxidation gives a sum of amino acid residues of only 35--45 weight-%, the glycoprotein nature of the inhibitor could be shown by staining the SDS-gels with Schiff's reagents and by carbohydrate determination with anthrone reagent.

Mechanism of senescence of red blood cells.

An integral hypothesis is submitted on the interaction of endogenous and exogenous factors in the mechanism of senescence of erythrocytes and on their selective phagocytosis by autologous macrophages. A method that allows quantitative determination and preparative yield of senescent erythrocytes is proposed.