Use of a diploid cell line for detecting the toxic components in medical immunobiological preparations

Besides specific antigens medical immunobiological agents (MIBA) contain chemical compounds (formaldehyde, aluminium hydroxide and mercury salt, merthiolate) in permissible concentrations. Therefore, the investigation of MIBA and their components should involve methods studying the effect of chemical compounds on cells and their structural components. For this purpose WHO recommends to use cell cultures. The results obtained show that cell cultures (constant and diploid lines) allow the differentiation in the degree of toxicity of chemical compounds constituting MIBA. Merthiolate had the strongest irreversible lethal effect. The technique can prove useful for more accurate evaluation of toxicity in inactivated bacterial and viral vaccines as well as in serum preparations. Cell culture can be successfully used for the detection of toxic components in vaccines and serum drugs, with the final safety tested by their injection to animals.     

Immunoenzyme analysis with visual demonstration for detecting antibodies to the tick-borne encephalitis virus

Good prospects for the use of enzyme immunoassay (EIA) with the simple visual indication of results have been shown with the detection of specific antibodies to tick-borne encephalitis virus in blood serum used as an example. When compared with such highly sensitive method as radioimmunoassay, visual EIA is inferior in both sensitivity and selectivity, but its special advantage is that it requires no instrument for evaluating the result.     

The glutamate receptor types determining concentrational dependence of its neurotoxic effect on rat cerebral cortex neurons

Mechanisms mediating neurotoxic glutamate effect on the rat brain cortex neurons developing in the primary tissue culture for 7 days have been studied. The neuron death identification was performed using the vital stain trypane blue and a fluorescent kit. Both dynamics and the neurodegeneration degree, produced by Glu and achieved by the experiment end depended on its concentration. For example, in the presence of 1 mmole/l and 10 mmole/l Glu the number of dead neurons by the 6th hour of recording was about 30 and 60%, respectively. The effect of 1 mmole/l Glu has the pharmacological sensitivity coinciding with the NMDA effect: it was potentiated by Gly, inhibited by AP5, and decreased essentially in the presence of 2 mmole/l Mg²⁺ in saline. The neurotoxic effect of 3 mmole/l Glu was resistant to effects of substances specific to towards NMDA-R, i.e., it seemed to be mediated by activation of other Glu-R. To confirm this suggestion there was studied the neurotoxic effect of AMPA and KA—agonists of the AMPA-R and KA-R. In the presence of both KA concentrations (30 and 300 μmole/l) its effect was similar and the number of dead neurons amounted to about 55% by the experiment end. Neurotoxicity of 10 μmole/l AMPA was expressed to the lesser degree: the number of dead neurons did not exceed 20% by 5 h of recording. However, addition of 100 μmole/l of cyclothiazide that eliminated AMPA-R desensitization was accompanied by a significant increase of the AMPA effect, it became as pronounced as the KA effect. It is essential that CNQX protected the neurons from death caused by AMPA and by KA actions. The data identify two components of the Glu neurotoxic effect. Effect of low concentrations is mediated by activation of NMDA-R, while effect of high concentration is determined by predominant activation of AMPA-R and KA-R.     

G-specific RNA-cleaving conjugates of short peptides and oligodeoxyribonucleotides

Artificial ribonucleases, conjugates of short oligodeoxyribonucleotides and peptides built of arginine, leucine, proline, and serine, were synthesized and assessed in terms of ribonuclease activity and specificity of RNA cleavage. A specific group of the conjugates was identified that display T1-ribonuclease-like activity and cleave RNA predominantly at G-X sequences. Circular dichroism study of the structures of the most active conjugates, free peptide (LR)4G, and oligonucleotides revealed that conjugation of oligonucleotide to the peptide results in a specific peptide folding that possibly provides ribonuclease activity to the conjugate.     

Molecular characterization of an ancient Hepatozoon species parasitizing the 'living fossil' marsupial 'Monito del Monte' Dromiciops gliroides from Chile

The Microbiotheriid Dromiciops gliroides , also known as 'Monito del Monte', is considered to be a threatened species and the only living representative of this group of South American marsupials. During the last few years, several blood samples from specimens of 'Monito del Monte' captured at Chiloé island in Chile have been investigated for blood parasites. Inspection of blood smears detected a Hepatozoon species infecting red blood cells. The sequences of DNA fragments corresponding to small subunit ribosomal RNA gene revealed two parasitic lineages belonging to Hepatozoon genus. These parasite lineages showed a basal position with respect to Hepatozoon species infecting rodents, reptiles, and amphibians but are phylogenetically distinct from Hepatozoon species infecting the order Carnivora. In addition, the Hepatozoon lineages infecting D. gliroides are also different from those infecting other micro-mammals living in sympatry, as well as from some that have been described to infect an Australian species of bandicoot. The potential vector of this parasite appears to be the host-specific tick Ixodes neuquenensis because the sequencing of a long amplicon determined the presence of one of the two lineages found in the marsupial.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 568–576.