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A method has been developed for preparing essentially pure primary cultures of neurons from 10-12 week old fetal human brain. This method is based on the 1) capacity of neurons to form multicellular aggregates, 2) cultivation in chemically defined medium, and 3) treatment with cytosine arabinoside as antimitotic agent. This procedure allowed the preparation of highly purified (95 per cent and more) neuronal aggregate cultures. Ultrastructural analysis of these cultures following one and 8 days has revealed their partial differentiation during cultivation.

Growth and differentiation of neurons and glia in spinal cord explants of 16 days old rat fetuses with teratogen-induced left-sided micromelia were studied. Progressive destruction of astrocytes that differentiate in interstitial zone of cultures was observed in 37% of explants of the left side, while the development was normal in cultures of the right side. Possible mechanisms leading to destruction of astrocytes in cultures of spinal cord regions that innervate anomalous limbs are discussed.

An attempt was made of a direct transfer to the recipient of postural asymmetry originating after the removal of half of the anterior lobe of the cerebellum in rats. Postural asymmetry of the hind limbs proved to develop in spinal rats after subdural injection of brain extracts of the pathological donors below the spinal section level. Specificity of this asymmetry depending on the side of the cerebellar lesion was shown. The type of the recipient's asymmetry repeated the donor's asymmetry exactly. The brain extracts of control animals produced no asymmetry in the recipients. Additional evidence of the peptide nature of the factor stimulating postural asymmetry development was obtained: pronase inactivated the active brain extract.

500--700 rat oocytes were solubilized in 0.3--0.6 ml of 1% sodium dodecyl sulphate (SDS) --0.06 tris-HCl, pH 6.7. The excess of SDS was removed in the form of unsoluble Ba2 (SDS) and the lysate was placed on the surface of 1% agarose microgel, performed in a glass capillar with the inner diameter 600 and the length of gel 7--8 nm. The microvolume (1.3 mcl) of monospecific antiserum against alpha1-human antitrypsin was placed on the opposite surface of the agarose gel. After 48 hours, the amount of microimmunoprecipitate was determined by staining the gel with Amido Black 10 B, followed by quantitative scanning using a double wave microspectrophotometer. The mean value of alpha1-antitrypsin was about 2.3+/-1.4 pcg per ovum. It is supposed that this antienzyme may terminate the "zone" and "cortical" reactions during the fertilization in mammals.

A model of spinal postural asymmetry produced by unilateral motor cortex destruction was developed. The spinal fixation time of postural asymmetry of cortical origin was determined. CSF way of spreading the factors that induce spinal asymmetry was demonstrated. The factor of spinal asymmetry was shown to be species-nonspecific.

It has been experimentally established that special hypophysiotropic factors--precursors of pose asymmetry factors (PAF) are found in the cerebrospinal fluid of donor animals with cortical lesions during the first postoperative hours. These factors, being specific for the location of the cortical lesion in donor animals, appear to be hypophysiotropic peptide substances inducing the production of corresponding PAF by hypophysial cells. The production of certain PAF by the rat hypophysial tissue cultures under the influence of cerebrospinal fluid from cats gives evidence in favour of species nonspecificity of PAF inductors.

A technique of microinjection of exogenic commercial lactate dehydrogenase into the zygotes of rats has been elaborated. A selective inhibition of exogenous LDH-3, LDH-4 and LDH-5 was registered in the ova-recipients. Attempts to reproduce the selective inhibition of LDH-3, LDH-4 and LDH-5 by a microhomogenate made of zygotes were not successful. The identification of LDH from ovocytes and exogenic LDH was made according to their electrophoretic mobility relative to Bromphenol blue and LDH-1.

The immunoprecipitation reaction for the determination of microamounts of alpha1-antitrypsin was conducted in the capillaries filled with a microvolume of a 1% agarose gel (the gel length was 7--8 mm, and the diameter--0.6 mm). Microamounts of the antigen and antiserum were applied to the surface of the opposite ends of the gel. Precision control of these manipulations was carried out by means of an ocular micrometer of a binocular lens. The amount of the formed immunoprecipitate in gel was calculated by the summated optic density after staining with amido black recorded by the method of double-wave microspectrophotometry. Sensitivity of the method was 0.3--1.0 ng of alpha1-antitrypsin. The linear plot between the amount of alpha1-antitrypsin and the amount of the precipitate formed was found within the range of 1--25 ng of protein. The error was about 10%.

In the tissue culture of the newborn rat cerebrum structural peculiarities of the glial growth have been investigated, using scanning and transmissive microscopy. Glioblasts are the first to migrate into the growth zone from the explant. Formation of the glial network is accompanied with formation of multilayered structures. In the cerebral tissue culture 3 zones are distinguished differing from each other by their morphofunctional peculiarities and behavior of the glial cells: growth zone, intermediate and central ones. The growth zone is characterized with permanent moving and modification of glial cells, participating in formation of cellular cords, networks and layers. Glioblasts are predominate cells in this zone. The intermediate zone consists of multilayered glial elements, possessing a high proliferative activity. The central zone, where neuropil and neurons consisting of numerous processes are situated, is characterized with a high degree of differentiation of glial elements. The central part of the explants is covered with epitheliomorphic layer of glial cells, predominantly consisting of cytoplasmic and fibrous astrocytes. The data presented demonstrate that differentiation of glial elements into various types occurs in the cerebral cultures exclusively in the area of the neural cells localization and, possibly, under their immediate influence.

Data are provided on cytodifferentiation of the cerebral cortex cultured cells taken from 10-12 week old embryos of man. It is shown that low differentiated neuroblasts well survive in culture for 21 days. Mature granular cells and middle pyramidal neurons are revealed in cultures. The number of morphological criteria may testify to the maturity of neurons: the presence of the Nissl substance, differentiation of dendrites and axons; the presence of various types of synapses. The absence of myelinized fibres testifies to the insufficient maturity of the cultures, that is probably associated with employing the low differentiated nervous tissue for cultivation and with insufficient cultivation period.