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Background: impaired intracortical myelination most pronounced in prefrontal cortex is tightly linked to inadequate information processing in schizophrenia. Previously we reported a significant decrease in the numerical density (Nv) of oligodendrocytes (Ol) and oligodendrocyte clusters (OlC) in layers 3 and 5 of the prefrontal cortex, Brodmann area 10 (BA10) in schizophrenia. To date there are few studies on the possible role of perineuronal oligodendrocyte satellites (Sat-Ol) in human brain pathology.Aim of the study: to estimate the number of Sat-Ol per pyramidal neuron in layer 3 of BA10 in schizophrenia as compared to healthy controls and to evaluate the possible correlations between the number of Sat-Ol and NvOl or NvOlC in schizophrenia and normal controls.Material and methods: we investigated the number of Sat-Ol per pyramidal neuron in sublayers 3a, 3b and 3c of layer 3 of BA10 in schizophrenia (n = 20) as compared to healthy controls (n = 20) in the same section collection previously used for the study of the NvOl and NvOlC.Rеsults and conclusion: we found a significant reduction in the number of Sat-Ol in schizophrenia as compared to the control group (17 and 24% resp., p < 0.01). There were no correlations between the number of Sat-Ol and the NvOl or NvOlC. The comparison of current data to similar findings from our previous studies in BA39 and BA40 of the inferior parietal cortex indicates that specific features of oligodendrocyte alterations and their correlation patterns may be associated with specific activity-driven plasticity of corresponding networks in normal and schizophrenia brains.

Objectives. Intravital studies have shown that alterations to myelination in the gray matter of the cortex in schizophrenia are the most marked in the prefrontal cortex. The authors have previously observed a decrease in the number density of oligodendrocytes (ND OL) in layers 3 and 5 of field 10 of the prefrontal cortex in schizophrenia. Proliferation of oligodendrocyte precursors in the brains of adult animals and humans is known to lead to the formation of oligodendrocyte clusters (OLC) and this process is linked with function-dependent axon myelination. The aim of the present work was to determine ND OLC and the ratio of ND OLC to ND OL in the functionally diverse supra- and infragranular layers of field 10 in health and schizophrenia. Materials and methods. ND OLC was determined in layers 3a, 3b, and 3c (supragranular) and 5a (infragranular) of field 10 using an optical dissector on Nissl-stained sections in 17 cases of schizophrenia and 20 people without mental disorders. Results and conclusions. Decreases in ND OLC were seen in both the supra- (by 32%, p < 0.02, Duncan test) and the infragranular (by 50%, p < 0.001) sublayers of field 10 in schizophrenia as compared with the control group. A decrease in the ND OLC/ND OL ratio was significant only for sublayers 2a (p = 0.015) and 5a (p < 0.001). In the control group, ND OLC showed a significant correlation with ND OL in sublayers 3b, 3c, and 5a (R ≥ 0.59, p ≤ 0.006), while in the schizophrenia group only layer 5a showed a persisting positive correlation (R = 0.8, p = 0.00001) between measures. A deficit of OLC in field 10 in schizophrenia may be due to impaired proliferation and/or differentiation of OL precursors. The nature of the interaction between ND OLC and ND OL presumptively depends on the characteristics of the connections between the corresponding cortical sublayers and their changes in schizophrenia.

The scientific literature contains several hypotheses for the pathogenesis of schizophrenia. The most widespread hypotheses for schizophrenia are the dopaminergic, serotoninergic, and glutamatergic hypotheses. There is also the suggestion that other neurochemical systems are involved in the pathogenesis of schizophrenia, particularly the GABAergic. This review considers published data on derangements of GABAergic interneurons in schizophrenia, taking account of data on post-mortem, neuroimaging, molecular-genetic, and electrophysiological research. A hypothesis for the pathogenesis of schizophrenia based on impairments to the myelination of GABAergic interneurons is proposed, these impairments leading to decreases in the numbers of intra- and interhemisphere coherent connections and the appearance of symptoms of the disease.

Oligodendrocyte abnormalities are thought to be one of the key cellular pathologies involved in disturbances of neuronal connectivity in schizophrenia.The density of oligodendrocytes in layer III of the prefrontal cortex, BA10, in schizophrenia (n=20) was compared to controls (n=20) using optical dissector method. MANCOVA was applied for group comparisons.The density of oligodendrocytes was significantly lower in each sublayers of layer III (≤20% p≤0.05) in the schizophrenia group as compared to the control group. The deficit of oligodendrocytes in the prefrontal cortex in schizophrenia may be of developmental origin or the result of alterations in the neural tissue of the brain during disease course.Цель исследования. Повреждения структуры и нарушение функции олигодендроцитов, возможно, являются одним из ключевых звеньев патогенеза, которые приводят к нарушению межнейрональных связей и дезинтеграции работы нейронных сетей при шизофрении. Материал и методы. Определяли численную плотность олигодендроцитов в слое III поля 10 префронтальной коры при шизофрении (n=20) по сравнению с контролем (n=20) методом оптического диссектора. Статистический анализ MANCOVA применяли для сравнения исследуемых групп. Результаты и заключение. Численная плотность олигодендроцитов достоверно снижена во всех подслоях слоя III (≤20%, p≤0,05) в группе больных шизофренией по сравнению с контролем. Дефицит олигодендроцитов в префронтальной коре при шизофрении может быть результатом нарушения развития нервной системы, а также изменений в ткани головного мозга, происходящих в течение заболевания.

The spatial organization of oligodendrocytes and pyramidal neurons in the anterior limbic cortex in health and schizophrenia was studied using automated two-dimensional image analysis. Layer III of this area of the cortex in schizophrenia showed a 20% reduction in the minimal distance between oligodendrocytes and their nearest neurons and 10% and 9% reductions, respectively, in the mean maximum distance between neurons and their nearest oligodendrocytes. Thus, this automatic image analysis method allows assessment of the spatial organization of neurons and glial cells in the cerebral cortex not only in health, but also in mental pathology.

Many hypotheses have been proposed for the pathogenesis of schizophrenia. The most common hypotheses of schizophrenia are dopaminergic, serotoninergic, glutamatergic. There are also assumptions about involvement of other neurochemical systems, in particular GABAergic, in the pathogenesis of schizophrenia. The available data on the damage of GABAergic interneurons, taking into account the results of postmortem, neuroimaging, molecule-genetic, electrophysiological studies in humans and fundamental studies in animals, are discussed. The author suggests that one of the pathophysiological mechanisms of the pathogenesis of schizophrenia may be a disturbance of myelination of GABAergic interneurons leading to a decrease in the number of intra- and interhemispheric coherent connections, and eventually to the development of symptoms of the disease.В научной литературе существует несколько гипотез патогенеза шизофрении. Наиболее распространенные гипотезы шизофрении - дофаминергическая, серотонинергическая, глутаматергическая. Существуют также предположения о вовлеченности в патогенез шизофрении и других нейрохимических систем, в частности ГАМКергической. В представленном обзоре рассматриваются имеющиеся в литературе данные о повреждении ГАМКергических интернейронов при шизофрении с учетом данных постмортальных, нейровизуализационных, молекулярно-генетических, электрофизиологических исследований. Изложена гипотеза патогенеза шизофрении, основу которой составляют нарушения миелинизации ГАМКергических интернейронов, приводящие к уменьшению числа внутри- и межполушарных когерентных связей и возникновению симптомов заболевания.

The aim of the present work was to produce organotypic cultures of human embryo brain tissues, as needed for investigation of the effects of serum factors on mental diseases and their pharmacological treatment. Cultures were made using slices of medulla oblongata from human embryos aged 9-10 weeks, obtained from medical abortions. Free-floating slices were cultured using a modified roller method for four weeks. Light and electron microscopy, along with immunocytochemistry, demonstrated that cultured slices showed differentiation and growth of neurons, astro- and microgliocytes, with formation of the synaptic contacts and glioneuronal interactions typical of organotypic cultures. However, along with differentiated neurons and glial cells, there was some persistence of undifferentiated cellular elements with signs of stem cells and neuron and gliocyte precursor cells. These experiments showed that organotypic roller cultivation of free-floating slices of human embryo brain tissue can be used to study the processes of neuron and gliocyte development, the mechanisms of neurotoxicity and neuroprotection using a variety of morphological (including stereological) and biochemical study methods.

To study the spatial organization of oligodendrocytes and pyramidal neurons in the frontal limbic cortex of patients with schizophrenia and healthy controls, the authors used a method of two-dimensional automated analysis of images. The decrease in the minimal distance between the oligodendrocyte and the nearest neuron by 20% and in the mean and maximal distances between neurons and the nearest oligodendrocytes by 10% and 9%, respectively, was found in the layer III in patients with schizophrenia. Therefore, this method allows to characterize the spatial organization of neurons and glia in the brain cortex not only in the normal brain but also in mental pathology.

To specify a possible role of oligodendrocyte deficit in the development of interhemispheric asymmetry.Perineuronal oligodendrocytes were counted in layer III, Broadmann area 39, in Nissl-stained sections in both hemispheres of post-mortem brain samples of patients with schizophrenia and controls (healthy people).The left-hemispheric asymmetry of perineuronal oligodendrocytes was found in the control group. A decrease of this parameter by 22% and the absence of the interhemispheric asymmetry were noted in patients with schizophrenia. It has been concluded that perineuronal oligodendrocyte deficit in the inferior parietal cortex in schizophrenia can contribute significantly to disturbed interhemispheric asymmetry of this brain structure.Цель исследования. Установление возможной роли дефицита олигодендроцитов в развитии межполушарной асимметрии при шизофрении. Материал и методы. На срезах, окрашенных по методу Ниссля, измеряли число перинейрональных олигодендроцитов в слое III поля 39 (по Бродману) в обоих полушариях аутопсийного мозга при шизофрении по сравнению с контролем (психически здоровые). Результаты и заключение. Установлено наличие левополушарной асимметрии числа перинейрональных олигодендроцитов в контрольной группе. В группе шизофрении выявлено снижение этого показателя на 22% по сравнению с контролем и отсутствие межполушарной асимметрии. Сделан вывод, что дефицит перинейрональных олигодендроцитов в нижней теменной коре при шизофрении может вносить существенный вклад в нарушение функциональной асимметрии этой структуры мозга.

Autopsy samples from the prefrontal cortex were obtained from 22 schizophrenic cases and 22 normal controls. Capillaries and oligodendrocytes were viewed in paraffin sections stained with a Luxol-fast blue + cresyl violet. Electron microscopy was applied to study the ultrastructure of oligodendrocytes. Numerical density of pericapillary oligodendrocytes was measured in layer V of Broadmann's area 10. Subjects with schizophrenia had a significantly lower (-20,8%) numerical density of pericapillary oligodendrocytes compared to controls. The analysis for schizophrenic subgroups with predominantly positive or predominantly negative symptoms revealed a significant decrease in the numerical density of pericapillary oligodendrocytes only in the latter one (-29,4%). The numerical density of pericapillary oligodendrocytes in cases with predominantly positive symptoms also decreased (-8,3%) but not differed significantly from the controls. Electron microscopy revealed the prominent ultrastructural dystrophic and degenerative alterations of pericapillary oligodendrocytes in the prefrontal cortex in schizophrenic brains. The present study points out that the population of pericapillary oligodendrocytes is involved in the pathogenesis of schizophrenia. Damage and loss of pericapillary oligodendrocytes might lead to disruption of the blood-brain barrier and as a result to dysregulation of metabolic trafficking across the blood-brain barrier in the prefrontal cortex in schizophrenia.

Using optical dissector methodology, a morphometric study of numerical density of oligodendroglial cells in layer VI and in adjacent white matter of Broadmann area 10 has been conducted in 23 postmortem brains of schizophrenics and 20 matched controls. Comparing to controls, a significant reduction of numerical density of oligodendroglial cells was found in layer VI (by 31%) and adjacent white matter (by 12%) of schizophrenic patients. The data obtained, as well as ultrastructural signs of oligodendroglial cells apoptosis and necrosis found earlier by the authors, may indicate a loss of these cells in the prefrontal cortex in schizophrenia, which may, in its turn, result in neuronal and high cortical dysfunctions.

Bifunctional antibodies (bABs) having a double specificity to alpha-endorphin (alpha-END) and horseradish peroxidase (HRP) were produced by hybridoma technology. The antibodies constituted about 28-29% of all immunologically active IgG secreted by hybrid hybridoma (quadroma). The quadroma was isolated by fusion of two murine hybridomas (anti-HRP and anti-alpha-END) with distinct phenotypes: double mutant AMD(R)/NAT(S) and its wild type. To produce the double mutant phenotype, an actinomycin D-resistant (AMD(R)) mouse myeloma was used to initiate one of the parental hybridomas. bABs were purified from quadroma culture medium and ascitic fluids by sequential HRP-sepharose and alpha-END-sepharose affinity chromatography. With radioimmunoassay, the affinity of the individual anti-alpha-END combining sites of bABs was shown to be identical to that of parental monoclonal antibodies. Binding to the second antigen (HRP) did not affect the binding of bABs to alpha-END. bABs proved to be efficient for the determination of endorphins and their precursor proopiomelanocortin in immunohistology and immunoblotting.

Hybridoma technique was used to obtain a clone producing IgG antibodies. Paired helical neurofilaments isolated from the brain of patients suffering from Alzheimer's disease were used as an antigen during preparation of the clone. Antibodies recognize neurons with neurofibrillary changes. Specificity of the obtained antibodies to paired helical filaments was proved immunohistochemically. Monoclonal antibodies obtained are likely to be useful in the determination of the role played by pathological proteins in mutually twisted filaments formation.

A study was made of the effect of autopsy brain extracts from persons with dementias of different origin (Alzheimer's disease and senile dementia) on nervous tissue culture of human fetuses. Light microscopy showed a tendency towards an increase of the astrocyte count and expressivity of their immunocytochemical response to glial fibrillar acid protein after administration of brain extract from persons with Alzheimer's disease. Electron microscopy revealed a substantial rise of the frequency of occurrence of altered microtubules in the processes of ectodermal cells, particularly marked due to the effect of extracts from persons with senile dementia. It was also shown that cytoplasm of hypertrophied astrocytes was loaded with regulated bundles of +glial filaments (primarily in experimental culture series). Brain extracts from persons with Alzheimer's disease induced as well the formation of typical complexes in the synaptic structures.

Four mouse monoclonal antibodies (E11, A8, F8, H5) to alpha-endorphin have been produced. The antibodies bind 12.5, 20.6, 9.6, 6.6% of 125I-beta-endorphin and 35.5, 15.1, 12.8, 12.2% of 125I-gamma-endorphin; the binding of 125I-alpha-endorphin being taken for 100%. The binding of antibodies E11, A8, F8 and H5 to 125I-alpha-endorphin was 50% inhibited by unlabeled ligand in concentrations 5, 50, 30 and 35 nM respectively. Using tissue sections of rat pituitary it was shown that antibody E11 can be used for the localization of endorphin producing cells by immunofluorescence. The antibodies F8 and H5 effectively detected endorphin precursor proopiomelanocortin by immunoblotting.

During autopsy of brains from 17 schizophrenic patients and 14 mentally normal subjects the authors studied metabolic characteristics in hyperchromic neurons, using methods of electron cytochemistry. The parameters of plastic and energy metabolism investigated included ribonucleoproteins (RNP), Mg-activated ATPase and succinate dehydrogenase (SDH). Two types of neurons with a different degree of hyperchromia and a decrease in metabolic activity were identified. The type I neurons were characterized by a marked decrease in the activity of the studied enzymes and the number of RNP particles, type II neurons by almost complete absence of enzymic activity and a sharp decrease in RNP particles. The results obtained make it possible to consider the hyperchromic neuron as a cell with a diminished functional activity.

Biological fluids (blood serum, cerebrospinal fluid) and brain extract obtained from patients with Alzheimer's disease (6 cases), simple senile dementia (5 cases), and other atrophic processes (1 case) were administered into the nutrient media of human fetal brain tissue culture. It was found that brain tissue extract obtained from patients with Alzheimer's disease stimulated accumulation of filamentous material in neurons while the CSF induced the formation of orderly filamentous rings. The effect of blood serum was characterized by nonspecific manifestations in the form of accumulation of structurally heterogeneous lamellar corpuscles.

Electron-cytochemical methods were used to study the distribution of acetylcholinesterase (ACE) activity in the brain in postmortem cases of Alzheimer's disease. The findings showed a decreased number of ACE-positive neural fibers in the upper cortical layers. The reduction was most pronounced in the temporal and parietal lobes of the cortex and absent in the occipital lobe. The disclosed cytochemical changes confirm the presence of disorders in the cholinergic system in the brain cortex in Alzheimer's disease.

Upon cultivation of the brain tissue and skin-muscle tissues of human embryos, a polyimide film was used as a lining. The optimal conditions of the preliminary processing of the lining (sterilization, washing) are described. An easy separation of the polyimide film from the media (in the process of tissue treatment for electron microscope studies) facilitates the use of the material for light and electron microscopy without damaging the culture.

The electron cytochemical reaction to nucleoside diphosphatase allows the differentiation in the rat brain of the cells of ectodermal orgin (neurocytes, astrogliocytes, oligodendrogliocytes) from the cells of mesodermal origin (microgliocytes, macrophages, endotheliocytes, pericytes). In the former group of cells, the product of the histochemical reaction was localized intracellularly (in the tubules of the cytoplasmic network and laminar complex) whereas in the latter it was localized only on the plasma membrane and never intracellularly.

Electron cytochemistry was employed to identify microglial cells by nucleoside diphosphatase (NDPase) in the senile plaques of the autopsy brain in Alzheimer's disease and senile dementia. It has been elucidated that processes of microglial cells enter a senile plaque and are closely connected with amyloid accumulation. A positive reaction to NDPase revealed in the extracellular substance suggests that these cells play an important role in the accumulation of amyloid in a senile plaque.

A complex morpho-functional investigation of the rat liver was performed after bilateral subdiaphragmal vagotomy by means of light, electron microscopy methods and a quantitative histochemical method. Some ultrastructural disorders in hepatocytes and in stellate reticuloendotheliocytes were revealed, with their maximal manifestation 7 days after vagotomy. At later stages (45 and 90 days), compensatory-restorative processes develop resulting in considerable (but not complete) normalization of the organ's structure. Quantitative histochemical investigations have demonstrated that even at the highest degree of the resulted disorders the liver preserves its ability to synthesize and accumulate glycogen, but the intensity of the process is considerably lowered. Functional changes are reversible in their character and correlate to the degree of structural disorders.

Four mouse monoclonal antibodies (E11, A8, F8, H5) to alpha-endorphin have been produced. The antibodies bind 12.5, 20.6, 9.6, 6.6% of 125I-beta-endorphin and 35.5, 15.1, 12.8, 12.2% of 125I-gamma-endorphin; the binding of 125I-alpha-endorphin being taken for 100%. The binding of antibodies E11, A8, F8 and H5 to 125I-alpha-endorphin was 50% inhibited by unlabeled ligand in concentrations 5, 50, 30 and 35 nM respectively. Using tissue sections of rat pituitary it was shown that antibody E11 can be used for the localization of endorphin producing cells by immunofluorescence. The antibodies F8 and H5 effectively detected endorphin precursor proopiomelanocortin by immunoblotting.

Using an electron cytochemical method and adenylylimidodiphosphate (AMP--PNP) as substrate, the localization of adenylate cyclase activity was determined in the rat's adenohypophysis. This activity was discovered in the perinuclear space, in the canaliculi of the endoplasmic reticulum and Golgi complex, in mitochondria, on the external surface of the plasma membrane. In sinusoidal capillaries, the reaction product was localized on the plasma membrane, in perinuclear space, endoplasmic reticulum and mitochondria. The addition of isoproterenol and sodium fluoride to the incubation medium led to a rise in adenylate cyclase activity.

Monospecific polyclonal antibodies to acid fibrillar astroglial protein allowed to reveal the sites of the filaments accumulation within the cells and perform the characterization of the tissue culture in terms of its cellular composition ectodermal and mesenchymal. The data suggest that in distinct terms of explanation of the human embryonic nervous tissue in the culture identical epitopes (antigen determinants) could be formed by intracellular fibrillar structures even in the cells of different origin.