Conditioned defensive reflex in the edible snail (molecular-genetic aspects)

The proliferation of glioma cells requires cholesterol, which could be provided by synthesis within the cells or by uptake of cholesterol esters in particles of Low Density Lipoprotein (LDL). Cholesterol esters and cholesterol were therefore analysed in human glioma tissue, its surrounding areas and serum from 40 patients. The analyses revealed an increased concentration of cholesterol esters up to 100 times (0.1-10 mumol/g) in both tumour-tissue and surrounding areas compared with control material (< 0.1 mumol/g). The analyses also demonstrated that cholesterol esters in tumour tissue eminated mainly from serum. The cholesterol concentrations were significantly lower in tumour tissue compared with surrounding areas as expected. These results indicate that tumour cell proliferation utilises serum derived cholesterol esters presumably carried by LDL particles.     

Development of a method for creating a colony of Macaca mulatta, free of herpes B virus infection

To form the colony of monkeys, free of herpes B virus, the serological study was made with the aim of finding out the carriers of this virus. 482 rhesus macaques (Macaca mulatta) from the Adler monkey house were examined for the presence of antibodies to herpes B virus by the method of point immunoblotting with the use of Herpes virus simiae as antigen. The contamination of monkeys in different open-air cages varied from 12.5% to 92%. In different age groups, it was 27% in nonpubescent monkeys (49 out of 182 animals), 55% in adolescent monkeys (55 out of 99), 73% in pubescent monkeys (131 out of 179) and 95% in monkeys over 15 years (21 out of 22 animals). 9 groups of rhesus macaques (comprising altogether 81 animals), free of herpes B virus, were selected. The monkeys were repeatedly tested within a year; after that 10-17% of formerly seronegative monkeys were rejected and removed from the selected group. After the third testing 2.5% more of the animals were found to have seroconversion. The colony of rhesus macaques thus created exists at present. The animals are subjected to constant serological observation.     

Pharmacological correction of lipid peroxidation during hypoxia and possibility to enhance human resistance to high altitude by using preparations of the metabolic type of action

In simulating acute hypoxic hypoxia with the participation of male volunteers, the authors investigated the antihypoxic and antioxidative activity of metabolic drugs (jakton, amtizole succinate, nootropil, probucol, and a mixture which consists of jakton, amtizole succinate, and probucol). The pharmaceuticals were shown to have heterodirectional effects on lipid peroxidative processes. Drugs having a pronounced antioxidative activity (such as probucol and the mixture) promotes oxygen utilization during hypoxia and posthypoxic reoxygenation chiefly by the oxygenase pathway. This rearrangement of oxygen utilization processes caused an increase in human high-altitude resistance. The use of the above drugs is a promising trend in the development of an adaptative response to hypoxia in persons engaged in hazardous jobs.     

Beta-thalassemia in Iran: a high incidence of the nonsense codon 39 mutation on the island of Queshm

Optic disc blood flow velocity was measured in healthy patients, those with primary open angle glaucoma (POAG), and patients with normal pressure glaucoma (NPG). The velocity of the red blood cells (RBCs) in the capillaries of the optic nerve head (ONH) has been measured with a laser Doppler velocimeter (LDV), and blood viscosity has been evaluated notably by determining the aggregability of the RBCs with an erythroaggregameter. Our results in POAG patients and NPG patients showed that their optic nerve blood flow velocity was reduced and that the aggregability of the RBCs was increased. The hyperaggregability of the erythrocytes is responsible for the increase of the local viscosity in the papillary capillary network. These haemodynamic modifications observed in patients with glaucoma support the hypothesis of a vasogenic mechanism that could impair the optic nerve in glaucoma patients.     

Mapping of specific and promiscuous HLA-DR-restricted T-cell epitopes on the Plasmodium falciparum 27-kilodalton sexual stage-specific antigen

We have characterized HLA-DR-restricted T-cell epitopes on the 27-kDa protein (Pfg27), a sexual stage-specific antigen, of the human malaria parasite Plasmodium falciparum in subjects with a history of malaria. Pfg27, expressed early in the sexual stages, is recognized by monoclonal antibodies capable of reducing the infectivity of gametocytes in mosquitoes. By using 16 Pfg27-specific CD4(+)-T-cell clones derived from three donors, seven different T-cell epitopes were identified. Among them, P11 (amino acids 191 to 210 of the Pfg27 sequence, IDVVDSYIIKPIPALPVTPD) was found to contain a previously described binding motif for multiple HLA-DR allotypes. Indeed, P11 was found to be promiscuous in that it could be recognized by T cells in the context of at least five different HLA-DR molecules. The cytokine profile of the clones was mixed. Seven of nine T-cell clones exhibited a Th0-like cytokine profile, producing high levels of gamma interferon (IFN-gamma) and interleukin-4 (IL-4) upon stimulation with specific peptides and mitogens. The other two clones had a Th1-like cytokine profile with high expression of IFN-gamma and no IL-4. Identification of a promiscuous epitope in Pfg27 could play a significant role in the design of a subunit vaccine for suppressing malaria transmission.     

Translation eukaryotic initiation factor 4G recognizes a specific structural element within the internal ribosome entry site of encephalomyocarditis virus RNA

A complex of eukaryotic initiation factors (eIFs) 4A, 4E, and 4G (collectively termed eIF4F) plays a key role in recruiting mRNAs to ribosomes during translation initiation. The site of ribosomal entry onto most mRNAs is determined by interaction of the 5'-terminal cap with eIF4E; eIFs 4A and 4G may facilitate ribosomal entry by modifying mRNA structure near the cap and by interacting with ribosome-associated factors. eIF4G recruits uncapped encephalomyocarditis virus (EMCV) mRNA to ribosomes without the involvement of eIF4E by binding directly to the approximately 450-nucleotide long EMCV internal ribosome entry site (IRES). We have used chemical and enzymatic probing to map the eIF4G binding site to a structural element within the J-K domain of the EMCV IRES that consists of an oligo(A) loop at the junction of three helices. The oligo(A) loop itself is not sufficient to form stable complexes with eIF4G since alteration of its structural context abolished its interaction with eIF4G. Addition of wild type or trans-dominant mutant forms of eIF4A to binary IRES.eIF4G complexes did not further alter the pattern of chemical/enzymatic modification of the IRES.