A Monoiodotyrosine Challenge Test in a Parkinson's Disease Model.

Early (preclinical) diagnosis of Parkinson's disease (PD) is a major challenge in modern neuroscience. The objective of this study was to experimentally evaluate a diagnostic challenge test with monoiodotyrosine (MIT), an endogenous inhibitor of tyrosine hydroxylase. Striatal dopamine was shown to decrease by 34% 2 h after subcutaneous injection of 100 mg/kg MIT to intact mice, with the effect not being amplified by a further increase in the MIT dose. The selected MIT dose caused motor impairment in a neurotoxic mouse model of preclinical PD, but not in the controls. This was because MIT reduced striatal dopamine to the threshold of motor symptoms manifestation only in PD mice. Therefore, using the experimental mouse model of preclinical PD, we have shown that a MIT challenge test may be used to detect latent nigrostriatal dysfunction.

A Comparative Analysis of CSF and the Blood Levels of Monoamines As Neurohormones in Rats during Ontogenesis.

According to the literature, the cerebrospinal fluid (CSF) in the cerebral ventricles contains numerous neuron-derived physiologically active substances that can function as neurohormones and contribute to volume neurotransmission in the periventricular region of the brain. This study was aimed at carrying out a comparative analysis of CSF and the blood levels of monoamines in rats during ontogenesis as an indicator of age-related characteristics of monoamine transport to body fluids and their function as neurohormones in volume neurotransmission in the periventricular region of the brain. We have shown that CSF in the perinatal period and adulthood contains the most functionally significant monoamines: dopamine, noradrenaline, and serotonin. A comparison of the monoamine levels in the CSF and blood of animals of different age groups revealed that CSF contains monoamines of predominantly neuronal (cerebral) origin and almost no monoamines derived from the general circulation. We also established that monoamines are found in the CSF at physiologically active levels that allow them to act as neurohormones in both reversible volume neurotransmission in the adult brain and irreversible regulation of brain development in the perinatal period.

[Biologically Active Peptides of King Crab Hepatopancreas].

Substances of a peptide nature isolated from the hepatopancreas of the king crab Paralithodes camtschaticus exhibited physicochemical properties and membranotropic and specific activities similar to those of membranotropic homeostatic tissue-specific bioregulators previously found in different mammalian and plant tissues. Their biological effect on vertebrate tissues was demonstrated on a model of roller organotypic cultivation of Pleurodeles waltl newt liver tissue.

[Peptide-containing fraction from a culture medium of Fusarium sambucinum: composition and biological effects].

The culture fluid of the fungus Fusarium sambucinum was investigated for the presence of new peptide-containing bioregulators, previously identified in various mammalian and plant tissues. A fraction containing peptides with molecular weights from 1000 to 2000 Da, which exhibited specific membranotropic activity and a number of physical and chemical properties characteristic of this group of bioregulators, was obtained. The effects of this fraction on the model roller organotypic cultivation of liver tissue of the Pleurodeles waltl newt in vitro were investigated for the first time. This fraction caused the additional activation of pigmented liver cells of newt (analogues to Kupffer cells of the liver of mammals) and provided the maintenance of cell-cell adhesive interactions in tissues. The results show that a new group of peptide bioregulators was present in the culture medium of the fungus F. sambucinum.

[Postfire restoration of organic substance in the ground cover of the larch forests in the permafrost zone of central Evenkia].

The role of ground fires in transformation of organic substances in the ground cover of larch stands in the permafrost zone of Central Siberia was studied, as was the postfire restoration dynamics of organic substances. Ground fires lead to a considerable decrease in concentrations and resources of organic carbon and its individual fractions in the ground cover, and restoration takes many decades.

[Histone competition for DNA and its possible role in the self-assembly of eu- and heterochromatin]. / Konkurentsiia gistonov za DNK i ee vozmozhnaia rol' v samosborke éu- i geterokhromatina.

Electrophoretic analysis of histones bound to DNA and remaining free in the mixtures of DNA with the total histone of chromatin in a medium of physiological ionic strength has shown that even the minimal weight excess of the total histone with reference to DNA (1.1:1) leads to the formation of nucleohistone impoverished in HI fraction because of histone competition for DNA. Within the histone/DNA ratio equal to 1.4, H3, H4, H2A and H2B are bound to DNA without competition, i.e. at a ratio in which they are added to DNA. Provided the histone/DNA ratio is higher in the mixture, there form nucleohistones enriched with H3 and H4 fractions. The role of histone competition for DNA in eu- and heterochromatin assembly is discussed.

[Effect of terrilytin on antifungal antibiotic activity]. / Vliianie terrilitina na aktivnost' protivogribkovykh antibiotikov.

The antifungal activity of terrilitine, an enzymatic preparation of microbial origin and its effect on the activity of antifungal polyenic antibiotics and griseofulvine were studied in vitro. It was found with the method of serial dilutions in Sabourand's liquid medium that terrilitine was active against C. albicans and certain dermatophytes. In combination with amphotericin B, amphoglucamine, mycoheptine, levorin, nystatin or griseofulvin it increased the activity of these antibiotics 2-16 times.