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A complex clinical and computer-assisted EEG study was carried out. 97 patients with acute ischemic cerebral hemisphere and 27 patients with acute ischemic brain stem stroke have been observed. A computer-assisted EEG was found to improve considerably diagnostic quality of stroke patients. It enables to determine the degree of functional lesions of the brain. Local changes of EEG-pattern prevail in patients with acute ischemic cerebral hemisphere stroke. Patients with acute ischemic brain stem stroke developed diffuse changes of EEG-pattern. Background EEG is the most representative technique to reflect bioelectric activity of the brain and it enables to assess the plasticity and reactivity of processes of the brain.

Complete suppression of polyadenylation of nuclear precursors of rat brain mRNA by cordycepin leads to degradation of some translatable sequences of both poly(A)(+)- and poly(A)- pre-mRNA localized in 80S hnRNP-particles. This fact has been established by comparative analysis of the data of two-dimensional gel-electrophoretic mapping of translation products synthesized in reticulocytic cell-free system using the exogenous purified templates of rapidly labelling translatable 9-17S hn RNA (pre-mRNA) isolated from brain 80S hn RNP particles of experimental (4 hrs after cordycepin injection) and control (injection of physiological solution) adult healthy male rats. Long contact of brain cells with cordycepin (4 or more hrs) creates conditions for formation of hnRNP-particles devoid of poly(A)+ RNA and poly(A)-binding proteins. These particles differ from "normal" ones by the value of the RNA/protein ratio, and by considerably lower resistance to the action of exogenous ribonucleases and endogenous RNase. Cordycepin does not have a direct effect on biosynthesis of nuclear poly(A)-binding proteins within the duration of the experiment (8 hrs). The phenomena described are discussed.

A procedure is developed for quantitative estimation of intraperitoneally administered unlabelled cordycepin in acid soluble pool isolated from rat brain tissue. The fraction containing 2'- and 3'-deoxyriboadenosine (cordycepin) in acid soluble pool of rat brain was isolated after consecutive chromatography on columns of Dowex 1 X 8, Dihydroxyboryl-SP 500 and Sephasorb-HP. At the same time, 2'-deoxyriboadenosine was isolated from the acid soluble pool fraction of control animals. Content of the antibiotic in brain tissue was estimated by its difference in these two fractions (control/experiment).

As a result of the complex comparative neurochemical study of the translation machinery functioning in the brain cells of three conventionally "phylogenetically related" species of wild timber voles (Clethrionomys glareolus, Clethrionomys frater and Clethrionomys gapperi), it has been found that the cytoplasm of brain cells of the latter contain an oligonucleotide (oligoribonucleotide) factor(s) with mol. weight below 1.0 KD which is able completely and highly selectively to inhibit the translation directed by mRNA which are species-specific templates and which were isolated from analogical tissue (brain) of "closely related" organisms. This phenomenon was found for the first time using special Cell-Free Translation Systems (CFTS) of very different variants of their composition consisting of the following main components: Post-Mitochondrial Supernatant (PMS), total cytoplasmic poly(A)+ mRNA or a species-specific poly(A)+ mRNA isolated form the PMS by affinity chromatography on the columns with the anti-mRNA1-FAB-(CNBr)-Sepharose, or purified 9S or 11S globin or histone specific mRNAs, respectively, and, finally a few samples of the CFTS used contain the additions of high or low molecular weight cytosolic compounds isolated from S150 fraction by ultrafiltration on Diaflo UM2 membrane with an exclusion limit of 1.0 KD. All CFTs components listed were isolated separately from the brain tissue of each organism studied. A new complex way for construction and using of the CFTS leads to an adequately documented conclusion which suggested the existence of special, so far uncharacterized in detail, cytoplasmic oligoribonucleotide factor(s) for efficient blocking for the cytoplasmic expression of "evolutionally renovated part" of genome; i.e., these factors seem to be sufficiently powerful suppressors of the translation of every mRNA template if the latter is not usual for the cell type containing the cytoplasmic suppressors mentioned in the case of a "so-called" newly found (perhaps, due to spontaneous but nonlethal mutagenesis) genes expression at the level of mRNA functioning in the cytoplasm. All findings and ideas of the paper are under discussion.

Rates of ATP production and protein synthesis rates were simultaneously studied using the isolated rat brain mitochondria and different types of brain polysomes (total, free, microsomal and mitochondrial membrane-bound). Protein synthesis was measured using a special reticulocyte lysate cell-free incubation medium. Prior to incubation, the intact ("unbroken") mitochondria were pretreated by several xenobiotics and natural metabolic effectors. The mitochondria incubated without these additions were used as controls. Chemically-promoted inhibition of ATP systhesis correlated with a significant activation of protein synthesis directed by the mitochondrial membrane-bound polysomes. The induction of ATP synthesis leads to a marked suppression of mitochondrial translation. Application of the selective translation blockers do not influence the ATP formation inside the isolated mitochondria. In general, mitochondrial membrane-found polysomes isolated from the intact normal organella are least active as compared with other tested polysomal fractions while the releasing of polysomes from mitochondrial membranes by Triton X-100 leads to the essential increase of the activity of these separated translation mechanisms. The separation of polysomes from the microsomal membranes do not change the activity of the former. A possible molecular mechanism, interdependence and biological significance of the established phenomena are discussed.

The intraperitoneal administration of a single dose of methyl mercuric chloride (MeHg) (10 or 50 nmol/g body weight) to adult male mice led to a significant stimulation of protein synthesis directed by isolated brain mitochondria in a special cell-free translation system prepared from rabbit reticulocyte lysates. The pre-treatment of the isolated mouse brain mitochondria from MeHg-injected and control (saline-injected) animals with an inhibitor (oligomycin) or inducers (ADP, succinate) of ATP synthesis showed that mitochondrial translation activity was high when ATP synthesis was suppressed and low when ATP synthesis was stimulated.

The content of sulphydryl and amine groups in water- and salt- soluble proteins of different areas of the rat brain was studied as affected by acute and chronic alcohol intoxication. With a relatively unchanged content of sulphydryl groups, noticeable variations are observed in the level of amine groups, most pronounced in proteins of the intermediate and middle areas of the brain. Under chronic intoxication the greatest changes in the content of the functional groups occur on the fourth day after cessation of the alcohol administration, when changes in the clinical state of the animals are most pronounced. It is supposed that the found shifts are caused by an acetaldehyde reversible blockade of amino groups and by the conformation rearrangement of protein molecules.

A procedure for quantitative estimation of cordycepin (3'-deoxyadenosine), a specific inhibitor of post-transcriptional polyadenylation of pre-mRNA and of a metabolite of cordycepin 3'-deoxyATP in rat brain tissue is described. The procedure is based on evaluation of an inhibitory effect on the synthesis of polyA in vitro of total nucleoside and nucleoside and nucleoside triphosphate preparations isolated from the animal brain after cordycepin administration. Homogenates of intact animal brain were used as a source of "crude" polyA polymerase preparations.

In rat brain cells low doses of cordycepin (3'-deoxyadenosine) practically do not inhibit biosynthesis of hnRNA with short 3'-terminal poly(A) segments. The same antibiotic doses are sufficient for effective inhibition of biosynthesis of hnRNA containing long poly(A) chains.

The poly(A+)/poly(A-)mRNA ratio and the half-life time of poly(A+)mRNA for mRNA metabolism in the liver and brain of rat in the course of ontogensis, late embryogenesis, postnatal development and upon ageing were determined. It was shown that in the course of ontogenesis both the ratio of poly(A+)/poly(A-)mRNA of free and membrane-bound polyribosomes and the half-life time of poly(A+)mRNA determined from the degradation kinetics in the presence of actinomycin D are changed. A possible role of poly(A) sequences in the regulation of mRNA life-time is discussed.

The investigations of the effects of Lithium salts on protein synthesis activity with special reference to neurochemical aspects may provide a fruitful development of a system of safe and effective, psychopharmacological methods for treatment and prevention of the Lithium-curable mental disorders complicated by general neurological (neuropathological) symptoms.

Intraperitoneal injection of different amounts of 6-methyl-2-ethyl-3-oxypyridine (6M2E3OP) to 3- and 18-month-old rats led to significant reduction of translating activity in vitro of membrane-bound polysomes of rat brain cells, but nor of free polysomes. This was more marked in the case of endoplasmic membranes of 18-month-old animals than in these of 3-month-old ones. Separation of polysomes from membranes by Triton X-100 resulted in restoration of template activity to the level of free polysomes. Forty eight hours after intraperitoneal injection of 6M2E3OP to 3- and 18-month-old rats the substance was found, by HPLC, only in endoplasmatic reticulum membranes of brain cells, but not in their cytoplasm. The xenobiotic did not change the age-dependent ratio of free and membrane-bound brain polysomes. At the same time the substance significantly inhibited the mean rate of synthesis of the longest polypeptide chains (MW 28-42,000 daltons) in cells of old animals.

Intraperitoneal injection of different amounts of Epygid (2-ethyl-6-methyl-3-oxypyridine) to 3- and 18-month-old rats led to significant reduction of translating activity in vitro of membrane-bound polysomes of brain cells, but not of free polysomes, more so for bound polysomes from 18-month-old animals than those from 3 months old. Separation of polysomes from membranes by Triton X-100 resulted in restoration of template activity to the level of free polysomes. The phenomenon may be related to incorporation of Epygid into the membranes of endoplasmic reticulum which contain a part of cell polysomes on their surface.

A study was made of the effect of cordicepin on the biosynthesis of rat brain heterogeneous nuclear RNA (hnRNA) fractions, such as poly(A-)hnRNA, oligo(A+)hnRNA and poly(A+)hnRNA differing in the size of poly(A)-segments. Cordicepin was shown to inhibit the biosynthesis of poly(A+)hnRNA alone. However, small doses of the antibiotic do not virtually inhibit the biosynthesis of hnRNA with shorter segments of poly(A). At the same time they inhibit the biosynthesis of hnRNA containing long chains of poly(A) in the 3'-end. A possible molecular mechanism of the phenomenon reviewed is under discussion.

We have investigated the effects of methyl mercury of mRNA metabolism in mouse brain cells in vivo. It was demonstrated that methyl mercury substantially reduces the rate of synthesis of ATP and poly(A)-segments of mRNAs. The molecular sizes of poly(A)-segments isolated from hnRNA and polysomal mRNA of the experimental animal brain are smaller than the dimensions of the same segments from the cellular RNA of intact mice. A fall in the mRNA polyadenylation rate seen under methyl mercury directly correlates with reduced metabolic stability (t 1/2) of the respective poly(A)+mRNA. The mean time of nuclear-cytoplasmic transport of these mRNAs (t0 is substantially increased under methyl mercury. At the same time, methyl mercury has no effect on the metabolism of brain polysomal poly(A)-mRNA. Direct addition of methyl mercury to an in vitro system containing excess ATP failed to affect the activity of poly(A) polymerase isolated from the brain of intact mice. The poison-induced alterations in the poly(A)+mRNA metabolism bring about a considerable reduction of the poly(A)+-fraction's share in the total polysomal mRNA and dramatic fall in the intracellular polysomes concentration. All the alterations in the examined metabolic parameters well correlate both with a reduced ATP content in the brain tissue and decreased rate of total protein synthesis in brain cells. Proceeding from these results as well as data from the literature, we developed a hypothetical model of a general molecular mechanism whereby methyl mercury inhibits protein synthesis in the brain.

Intraperitoneal injection of different amounts of 6-methyl-2-ethyl-3-oxypyridine (6M2E3OP) to 3- and 18-month old rats led to significant reduction of translating activity in vitro of membrane-bound polysomes of rat brain cells, but not of free polysomes. This regularity is more marked in the case of endoplasmic membranes of 18-month old than those of 3-month old animals. Separation of polysomes from membranes by Triton X-100 resulted in restoration of template activity of the former to the level of free polysomes. 48 h after intraperitoneal injection of 6M2E3OP to 3- and 18-month old rats, the substance is found by special HPLC technique only in endoplasmatic reticulum membranes of brain cells, but not in cytoplasm. The xenobiotic does not change the age-dependent quantitative ratio of free and membrane-bound polysomes of the brain. At the same time the substance significantly inhibits the mean rate of synthesis of the longest polypeptide chains (Mol. weight 28-42,000) in cells of old animals, unlike this rate in adult rats. Analysis of the obtained data and literature data permit us to make a conclusion on the ability of this xenobioticselectively to modulate a membrane-associated protein synthesis in the brain.

A simple method for fast fractionation of human postmortem brain total poly(A)+RNA has been developed. Guanidine thiocyanate extractable RNA was directly applied on the membranes of cellulose nitrate with immobilized oligo(dT) chains. After the electrophoresis in 35 mM tris-acetete buffer (pH 7.90) containing 10 mM EDTA and 35% formamide, the membranes were washed with the same buffer for removal of nonbinding poly(A)-lacking RNAs. Then, poly(A)+RNA fractions were selectively stained by 3,5-dimethylphenol in the presence of FeCl3 at pH 2.35. Finally, the resulting electrophorograms were scanned at 500 nm for quantitative evaluation of the data.