The role of cerebral regulatory structures in the formation of human EEG

This article generalizes the results of many years’ studies of the EEG of patients with tumorous lesions in the diencephalic, brainstem, and limbic structures, which fulfill the regulatory function in ensuring integral brain activity. The specific features of the inclusion of individual structures under investigation in the organization of the intra- and interhemispheric relations of cortical biopotentials were demonstrated against the background of diffuse changes in the biopotentials that reflect the systemic character of neurodynamic reorganizations when the regulatory brain structures are involved in the pathological process. This study expands the idea of the predominant functional connection of the diencephalic structures with the right hemisphere and brainstem structures with the left one with determination of the regional specific features of changes in the intrahemispheric EEG coherences. The distinguishing features of intercentral relations when the limbic structures are involved in the pathological process show similarity with the neurodynamic reorganizations in patients with lesions in both diencephalic and (even more so) brainstem structures. Universal elements were detected in the formation of integral adaptive reactions of the brain with lesions in its regulatory structures, which reflects their close functional interaction and makes it possible to consider them the individual links of an integral regulatory system. The study revealed reciprocal changes in various forms of electrical activity, which reflects reciprocation of interaction of individual regulatory structures. This is one of the EEG equivalents of the formation of adaptive-compensatory cerebral reactions. The specificity of influence of the studied regulatory structures are clearly seen in situations of their morphofunctional isolation observed during cerebral coma. In these conditions, when the cortex is functionally inactive, the authors demonstrated the dynamic character of changes in interhemispheric asymmetry, which reflects the dominance of individual links of the regulatory system playing the role of supreme regulator of life support of the body in critical states.     

Content of cyclic nucleotides and lipid peroxidation products in the brain of irradiated mice

The effect of radiation on the cyclic nucleotide content of mouse brain has been studied. High radiation doses have been found to increase cGMP and to decrease cAMP content of the brain. These alterations correlate with the processes of lipid peroxidation and formation of diene conjugates and malonic dialdehyde.     

Structural and functional characteristics of the lower tracheobronchial lymph nodes in the rat after administration of dimethyl sulfate

By means of microanatomical methods the inferior tracheobronchial lymph nodes in 36 Wistar rats have been investigated, when the animals have been subjected to the effect of dimethylsulfate (DMS) vapors. The effect of the substance in doses 0.1 and 2.0 mg/m3 for 2 and 14 days has been studied. Comparison of relative parameters of the structural components areas and the cytological profile of the lymph nodes has been performed. DMS effects for 2 and 14 days in the maximal tolerance concentration (MTC) results in increasing area of the connective tissue stroma and the cortical substance, in comparison with the control, as well as in decreasing area of the medulla substance. At the contact with DMS for 2 days (at a corresponding MTC) certain changes of the nodular cytological profile are noted. They demonstrate that to the given time of the experiment the adaptive processes in the lymph nodes have no time to develop completely. DMS effect for 14 days in the same concentration produces an increased destruction of cellular elements and inhibits the plasmocellular reaction intensity (in comparison to the control and the experiment for 2 days). DMS maximal concentration (2.0 mg/m3) results in decreasing area of the lymphoid noduli with germinative centers. Intensity of mitotic processes decreases and autoimmune processes develop.