Effect of ascorbic acid on the binding of 3H-GABA and 3H-glutamic acid to synaptosomes of the rat cerebral cortex

The effects of different concentrations of L-ascorbic acid (Asc) on Na+-dependent binding of 3H-GABA and 3H-DL-glutamic acid to rat brain cortical synaptosomes were studied. Asc, at a concentration nearly equal to brain extracellular one (3 X 10(-4) M), had no effect on specific and nonspecific 5H-GABA binding. At higher concentrations (10(-3) M) Asc strongly inhibited, and at lower concentrations (10(-6) M) considerably stimulated 3H-GABA binding. At a concentration of 10(-5)-10(-3) M Asc tended to decrease 3H-DL-glutamic acid binding.     

Range of the antigenic specificity of peptidoglycan in Staphylococcus aureus compared to other representatives of the Staphylococcus genus

In investigations based on the use of a highly sensitive test system permitting the detection of normal human antibodies to S. aureus peptidoglycan, the antigenic relationships between the peptidoglycans of S. aureus and other representatives of the genus Staphylococcus have been studied. Among other staphylococcal species, S. simulans, S. xylosus, S. hyicus, S. cohnii, S. hyicus s. s. chromogenes have been found to possess peptidoglycans most closely related to S. aureus peptidoglycans, while S. warneri and S. epidermidis peptidoglycans have proved to be least closely related to it.     

Vitamin E Induces Phosphatidylserine Externalization and Red Cell Adhesion to Endothelial Cells

Red blood cell (RBC) adhesion to vessel wall endothelium is a potent catalyst of vascular occlusion and occurs in oxidative stress states such as hemoglobinopathies and cardiovascular conditions. These are often treated with vitamin E (VitE), a “classic” antioxidant. In this study, we examined the effects of VitE on RBC adhesion to vascular endothelial cells (EC), and on translocation of phosphatidylserine (PS) to RBC surface, known as a potent mediator of RBC/EC adhesion, facilitating thrombus formation. Treatment of RBC with VitE strongly induces (up to sevenfold) PS externalization and enhances (up to 20-fold) their adherence to EC. The VitE hydrophilic analogue—Trolox—does not incorporate into cell membranes. Trolox did not exhibit any of these effects, implying that the VitE effect is due to its known ability to incorporate into cell membranes. The membrane-incorporated VitE significantly reduced the level of reactive oxygen species in H₂O₂-treated RBC, demonstrating that VitE elevates RBC/EC adhesion despite acting as an anti-oxidant. This study demonstrates for the first time that contrary to the common view of VitE as a beneficial supplement, VitE may introduce a circulatory risk by inducing flow-disturbing RBC adherence to blood vessel wall and the pro-thrombotic PS exposure.     

Mechanisms of induced processes in aqueous hemoglobin solutions at 77 K

ESR spectra of gamma-irradiated and frozen at 77 K human oxyhemoglobin and partially denaturated methemoglobin solutions were analysed. The quartet signal ascribed to the anion-radical of proximal histidine was shown to dominate in the spectra of both solutions. The spectra of methemoglobin solution irradiated with relatively small doses have an intensive singlet ascribed to the stabilized electron. The formation mechanism of free radicals is discussed.     

Effect of the phase state of lipids on their interaction with cobra cytotoxin

Interaction between cytotoxin of the Central Asia cobra venom and dimiristoylphosphatidylcholine bilayer depending on its phase state was studied by ESR with spin label. A conclusion can be drawn that the efficiency of cytotoxin effect on the membranes depends on their phase state. Cytotoxin molecules are incorporated into myophile region of the bilayer, only if the latter is in the liquid crystal state. The interaction between cytotoxins and lipids of the bilayer in a gel state is in the main conditioned by electrostatic forces.     

Comparative evaluation of the action of prostanoid inhibitors on uterine contractile function

Indomethacin and substance BW-755C in experiments on isolated myometrium striae of pregnant white rats exert an inhibiting effect on the contractile uterus function due to inhibition of cyclooxygenase or lipoxygenase ways of the arachidonic acid transformation. Prostaglandin F2 alpha is sensitive to functioning of the cyclooxygenase and lipoxygenase ways of the arachidonic acid transformation, while oxytocin--only lipoxygenase one. Conclusions rest on results from multiparametric analysis of the contractile uterus function suggested by authors and confirmed by the pattern recognition method--the Karunen-Loev orthogonal decomposition.