Effect of ischemia and reperfusion of the rat brain on lipid peroxidation and the protective effect of antioxidants

The experiments have been performed on 179 Wistar rats to examine the changes in the brain level of lipid peroxidation products upon 5-, 15-, 30- and 60-min ischemia and 5-, 20- and 60-min reperfusion and to study the protective effect of antioxidants. It has been found that ischemia is accompanied by the accumulation of lipid peroxidation products. The content increases by an average of 138-213% of the initial level. Brain reperfusion after 30-min ischemia was accompanied by an increase or maintenance of a high level of lipid peroxidation products. Ionol injection was accompanied by an increase in the survival of rats and prevented the accumulation of lipid peroxidation products after brain ischemia and reperfusion.     

Calcium desorption from the cornea while using complex-forming substances

The time course of calcium desorption from the eye cornea and the efficacy of the use of complex-forming substances during desorption were examined. Experiments with labeled calcium showed an active absorption of the ions by the normal cornea thereby making it turbid. The removal of labeled calcium from an isolated eye and from corneal pieces while using a combination of complex-forming substances and diffusion facilitating-papain was accompanied by the lowering of tissue turbidity. Application of such combinations might eliminate, in some cases, the necessity of surgical operations on the cornea.     

The molecular mechanism of adsorption immobilization of inulinase on polymer matrices

The conditions and mechanisms of the immobilization of inulinase on polymeric carriers were studied using the VION KN-1 and KU-2 cation-exchangers, VION AN-1 and AV-17-2P anion-exchangers, and the ampholyte KOPAN-90. The calculated data showed a significant role of van der Waals interactions and hydrogen bonding in the formation of virtually all inulinase complexes with the immobilization matrices. The AV-17-2P anion-exchanger was the only one of the studied polymer matrices that was unable to form hydrogen bonds with inulinase. The mechanisms of the interaction between inulinase and various ampholytes and cation and anion exchange resins differ from each other. The strongest differences are observed in mechanisms of the sorption of inulinase on VION KN-1 and chitosan matrices. Approximately 87% of the identical amino-acid residues are involved in the interaction of the enzyme with the KU-2 and AV-17-2P resins and the VION AN-1 and KOPAN-90 fibers.     

Male urine signals social rank in the Mozambique tilapia (Oreochromis mossambicus)

Background  

The urine of freshwater fish species investigated so far acts as a vehicle for reproductive pheromones affecting the behaviour and physiology of the opposite sex. However, the role of urinary pheromones in intra-sexual competition has received less attention. This is particularly relevant in lek-breeding species, such as the Mozambique tilapia (Oreochromis mossambicus), where males establish dominance hierarchies and there is the possibility for chemical communication in the modulation of aggression among males. To investigate whether males use urine during aggressive interactions, we measured urination frequency of dye-injected males during paired interactions between size-matched males. Furthermore, we assessed urinary volume stored in the bladder of males in a stable social hierarchy and the olfactory potency of their urine by recording of the electro-olfactogram.     

Optimization of the transfer and incorporation of viral DNA into cells using liposomes conjugated with influenza virus glycoprotein

Liposomes connected with influenza viral glycoproteins increase by 1-2 orders the specific infectiousness of DNA from SV-40 or monkey adenovirus SA7 as compared with the one registered when the standard method of calcium precipitation is used.     

Oxidative destruction of the heptaene antibiotic levorin

Levorin destruction in oxygen, argon or air at various temperature levels was studied. It was found that destruction of the antibiotic molecule was mainly due to its interaction with oxygen. As a result the heptaenic chromophore was oxidized and triene and tetraene formed. Oxidation of levorin was accompanied by splitting out of paraaminoacetophenone. Destruction of levorin in the absence of oxygen was retarded.     

Anti-ischemic action of a 1-hydroxy-2,2,6,6-tetramethylpiperidine derivative from a series of nitroxyl bioantioxidants

The experiments have been performed on 216 Wistar rats to examine anti-ischaemic action of the 1-hydroxy-2,2,6,6-tetramethyl-piperidine derivative (I), whose antioxidant properties were, earlier shown for model systems. Introduction of I (10(-4) M) into the perfusion medium and the subsequent storage (37 degrees C) of isolated liver was shown to decrease the accumulation of lipid peroxidation products (MDA). Compound I administrated (5 x 10(-6)-10(-5) M) in perfuse medium of isolated (Langendorff method) and ischemized (30 min, 37 degrees C) heart improves contractile function (Pmax) and decreases end-diastolic pressure at postischaemic period. In vivo injection of I increases (12 mg/kg, i.p.) the number of rats survival after sublethal time (2.5 h) of liver total ischaemia, increase (35 mg/kg, i.p.) the number of rats survival and improves parameters of heart function after ischaemic shock (6 h ischaemia and reperfusion of limbs). The analog of I, corresponding amine, possessing no antioxidant properties also fails to exhibit any anti-ischaemic effect.