The Blood-Brain Barrier in Neuroimmune Interactions and Pathological Processes.

The blood-brain barrier (BBB) is a kind of filter, highly selective in relation to various types of substances. The BBB supports the immune status of the brain and is an important regulator of neuroimmune interactions. Some of the molecular and cellular features of the BBB, as well as the five main pathways of neuroimmune communication mediated by the BBB, are analyzed in this article. The functions of the BBB in neuroimmune interactions in various diseases are discussed: multiple sclerosis and Alzheimer's and Parkinson's diseases. The latest data on BBB dysfunction in COVID-19 coronavirus infection caused by the SARS-CoV-2 virus are considered.

Effect of Skin Application of Dorogov's Antiseptic-Stimulant on Behavioral Reactions in Rats.

Local application of the Dorogov's antiseptic-stimulant onto the skin of 2-month-old male Sprague-Dawley rats in a low dose (0.5 g/kg/day) for 1 week increased motor and ultrasonic activity of experimental animals and the content of activated c-Fos+ neurons on the cingular, motor, insular, and pyriform cortex and in the striatum.

[CELL-MOLECULAR BASIS OFNEUROIMMUNE INTERACTIONS DURING STRESS].

The review represents a modern concept about cells-molecular basis of mechanisms of neuro-immune interactions, the data on the effects of destabilizing factors (electric pain stimulation, rotation, cold and psychoemotional stress) on the functioning of neurons and immune cells. It must be underlined, that under the stress conditions take place the alterations of ligand-receptors interactions on the membrane of lymphocyte. In particular the reaction of these cells to regulating signal - application of Interleikin-1 grow up after mild stress, but it falls down after an influence of severe stress factors. Special attention is paid to the role of the orexinergic system in mechanism of realization of CNS reactions to application of antigens. In the present work the possible methods of correction of imbalance in functional interactions between nervous and immune systems, caused by different destabilizing factors, are reviewed.

[Diagnosis of paraneoplastic polyneuropathy in patients with breast cancer and small cell lung cancer].

OBJECTIVES: To study possibilities of immunological and electrophysiological methods for the diagnosis of paraneoplastic polyneuropathy in cancer. METHODS: We studied 88 cancer patients using electromyography and immunological assay (serum neuronal antibodies). RESULTS: A symmetrical, distal, sensory-motor, axonal-demyelinating form of polyneuropathy can develop in breast cancer and small cell lung cancer. Onconeural antibodies were detected in the serum of more than half of study participants as well as in some healthy donors. Symptoms of polyneuropathy appeared earlier than the diagnosed tumor. CONCLUSION: The diagnostic value of the methods used for the early diagnosis of breast cancer and small cell lung cancer is emphasized.

[Receptors for oreksins: structure, localisation and activation mechanisms].

The review concerns morpho-functional characteristics of orexin receptors. The data on their structure, signal transduction pathways, biological effects of orexin receptors 1 or 2 depending on association with different G-proteins are presented. Localisation of orexin receptors in various CNS structures as well as in peripheral organs mediates regulation of different physiological functions by orexins. Low concentration of orexins in peripheral blood and orexin-containing cells in ganglions and internal organs suggests a possibility to activate orexin-sensitive cells distantly, paracrinely or autocrinely. The data on effects of selective or non-selective orexin receptor antagonists is analysed.

[Immunoreactivity of hypothalamic orexin neurons and expression level of preproorexin gene in them after lipopolysaccharide injection].

Hypothalamic orexin neurons are involved in the regulation of many physiological functions. The immunoreactivity of these neurons is shown to be altered after LPS injection. This phenomenon is characterized by definite time-space pattern and depends on dose of antigen applied. The expression level ofpreproorexin gene in rat hypothalamus was investigated in 2, 4 and 6 hours after injection of 25 and 500 mkg/kg b. w. LPS. Both injections of higher and lower doses resulted in the increase of expression level of preproorexin gene after 2 hours that could suggest an enhancement of orexin synthesis in neurons. There were no significant changes in 4 and 6 hours after injection. The comparative analysis of the data obtained earlier with immunohistochemistry, and the data shown in the present study suggest the mechanisms of orexin neurons reaction to injection of LPS in different doses, i. e. the more considerable prevalence of orexin utilization over its synthesis in hypothalamic cells after injection of subseptic (500 mkg/kg) dose of LPS.

[Response of hypothalamic orexin-containing neurons to stimuli of antigen and non-antigen nature].

Orexin is a hypothalamic peptide, a neurotransmitter described in 1998. Orexinergic neurons are localized in hypothalamic structures and play a significant role in regulation of various physiological functions. The localization oforexin-containing neurons and their projections in hypothalamus of Wistar rats and other structures of CNS are presented. The participation of orexinergic neurons in the regulation of feeding behavior and in the sleep/wake cycle as well as their involvement in the regulation of immune functions is discussed. There are experimental data, containing comparative analysis oforexin-containing neurons responses to stimuli of antigenic and non-antigenic nature, which suggest functional heterogeneity of orexin-containing neurons of hypothalamus that leads, particularly, to involvement of different neurons in the realization of brain reaction to antigen and non-antigen stimuli. Both analyses ofpreproorexin gene expression level and morphofunctional characteristics of orecxin-containing neurons of hypothalamus after antigen challenge suggest the possibility of their participation in the mechanisms of realization of brain reaction to antigen challenge.

[Comparative analysis of orexin-containing neurons reactions in the rat hypothalamus after lipopolysaccharide injection in different doses].

Nowadays many investigations are focused on the participation of orexin-containing neurons in CNS reactions caused by antigen injection, for instance lipopolysaccharide (LPS). The analysis of orexin-containing neuron: quantity in 2, 4 and 6 hours after injection of low non-septic dose of LPS in comparison with a higher subseptic dose, was carried on. The increase of the orexin-immunoractive neurons quantity was observed in 2 and 4 hours after administration of 25 meg/kg of LPS, whereas in 6 hours the decrease of it was demonstrated. Injection of higher dose of LPS (500 meg/kg) was shown to cause the more significant decrease of the quantity of orexin-positive neurons only in 6 hours after antigen administration. The obtained data evidence the alteration of orexin content detected in neurons somas and the shift of the balance of its synthesis and utilization processes in response to the LPS injection.

[Immunereactivity of hypothalamic orexin-containing neurons after restraint and cold stress in rats].

Studying of immunereactivity of orexin-containing neurons after restraint and cold stress has allowed to reveal a selective change of a degree ofimmunereactivity ofhypothalamic orexin-containing neurons. Orexin-containing neurons are located in structures 28, 29, 31 levels of brain slices and have the different degree of immunereactivity that indicates functional heterogeneity of a population of hypothalamic orexin-containing neurons. Structures and zones of hypothalamus involved in development of complex brain responses to restraint or cold stress applications were identified. Changes of immunereactivity of orexin-containing neurons located in the areas involved in system of regulation ofthermogenesis (DMH, PH and some zones LHA) suggest a possibility of orexin-containing neurons participation in thermoregulation.

Expression of the c-Fos gene in the rat hypothalamus in electrical pain stimulation and UHF stimulation of the skin.

Studies of the pattern of activation of hypothalamic cells in conditions of electrical pain stimulation demonstrated an increase in the proportion of c-Fos-positive cells (to 72.02-98.95%), predominantly affecting cells of size 10-50 microm2. UHF irradiation of the skin activated hypothalamic cells of size 10-70 microm2 in the paraventricular and dorsomedial nuclei and in the periforniceal zone of the lateral hypothalamic field. Combined action of UHF irradiation of the skin and electrical pain stimulation led to decreases in the proportions of cells activated as a result of pain stimulation in the anterior hypothalamic field, the ventromedial nucleus, and the basal part of the lateral hypothalamic field. Changes in the distribution of activated cells by size (mainly a reduction in the proportion of cells of area 10-30 microm2 and an increase in the proportion of larger cells) were detected in the ventromedial nucleus and the basal part of the lateral field. UHF irradiation of the skin was found to have a modifying effect, consisting of a reduction in the degree of activation of hypothalamic cells evoked by electrical pain stimulation.

Morphometric analysis of hypothalamic cells showing c-Fos proteins after movement restriction and EHF-irradiation.

A morphometric analysis of hypothalamic cells containing c-Fos-like protein detected by an indirect immunoperoxidase method was carried out to clarify the responses to movement restriction and skin electromagnetic high frequency (EHF) irradiation (7.1mm, 42.2GHz, 20mW output power) simultaneously to three acupuncture projection areas. The morphometry of c-Fos-protein positive neurons by their number and type was analyzed. Movement restriction (40min) induced c-Fos protein expression primarily in cells with 10-50mum(2) sizes (associative type neurons) only in anterior hypothalamic nucleus and lateral hypothalamic area; while additional EHF-irradiation of acupuncture projection areas (under movement restriction) induced c-Fos expression in all hypothalamic structures and mostly in cells with 70-150mum(2) sizes (relay type neurons), i.e. changed the pattern of activated cell type distribution. In conclusion, the findings show that modest stress under which experimental animals often are exposed increase c-Fos protein expression in hypothalamic centers and skin EHF-irradiation of acupuncture projection areas seem to increase that.

Stress-induced changes in cellular responses in hypothalamic structures to administration of an antigen (lipopolysaccharide) (in terms of c-Fos protein expression).

Stress is known to affect the intensity of the immune response. The involvement of central regulatory structures in mediating these changes was addressed by analyzing the extent of activation of neurons in the hypothalamus (in terms of the number of c-Fos-positive cells) in rats 2 h after i.v. administration of lipopolysaccharide alone and on the background of electrical pain stimulation. Studies were performed using 52 male Wistar rats weighing 200-250 g. c-Fos protein expression was studied by immunohistochemical analysis. Increases in the quantity of c-Fos-positive cells 2 h after administration of lipopolysaccharide were seen in the following hypothalamic structures: AHN, PVH, LHA, VMH, DMH, and PH. After electrical pain stimulation, the number of c-Fos-positive cells increased in these same hypothalamic structures (AHN, PVH, LHA, VMH, DMH, and PH). The combination of electrical pain stimulation and lipopolysaccharide administration led to a decrease in the extent of activation in hypothalamic structures AHN, PVH, LHA, and VMH as compared with the characteristic reaction to lipopolysaccharide without electrical pain stimulation. Electrical pain stimulation suppressed the intensity of the immune response induced by lipopolysaccharide (as assessed by local hemolysis and counts of the numbers of spleen antibody-forming cells). Thus, changes in the extent of activation of hypothalamic structures (AHN, PVH, LHA, VMH) correlated with the development of stress-induced immunosuppression, i.e., morphofunctional mapping of the extent of activation of hypothalamic structures allowed identification of which changes in hypothalamic cell activity occurred with stress-induced changes in immune system responses to antigen administration.

Intracellular expression of c-Fos protein in various structures of the hypothalamus in electrical pain stimulation and administration of antigens.

Application of different stimuli activated different hypothalamic structures. Immunohistochemical methods demonstrated changes in the numbers of c-Fos-positive cells in various hypothalamic structures after electrical pain stimulation and i.v. administration of antigens (bovine serum albumin (BSA) and lipopolysaccharide (LPS)). Increases in the numbers of c-Fos-positive cells in all the hypothalamic structures studied occurred after electrical pain stimulation and i.v. administration of antigens (BSA and LPS). The highest level of activation in hypothalamic structures was seen in the anterior hypothalamic nucleus (AHN) and posterior hypothalamic area (PH) after electrical pain stimulation and in the paraventricular nucleus (PVN) and lateral hypothalamic area level 28 (LHA-28) after i.v. administration of LPS. Comparative analysis showed that the level of activation of hypothalamic structures after electrical pain stimulation was significantly greater in the AHN, PVN, LHA, and PH than after i.v. administration of antigens (LPS and BSA). Administration of LPS led to more marked activation of cells in hypothalamic structures APH, PVN, LHA-28, dorsomedial hypothalamic nucleus (DMH), and PH (in terms of the numbers of c-Fos-positive cells) than administration of BSA.

Responses of hypothalamic orexin-containing neurons to cyclophosphamide, EHF-irradiation of the skin, and their combination in rats.

Orexins are neuromediators that participate in the regulation of feeding behavior, energy metabolism, circadian rhythms and perception of pain. The aim of the present study was to clarify the responses of the hypothalamic orexin-containing neurons to an intraperitoneal injection of cyclophosphamide (CPA), extremely high frequency (EHF)-electromagnetic stimulation of skin, which is used to modulate side effects of cytostatics and their combination. The activation of orexin-containing neurons was determined by recording of the intensity of c-Fos protein expression. Injection of cyclophosphamide (40mg/kg) or EHF-irradiation of the skin decreased the staining of orexin-containing neurons, which was most pronounced in the subfornical region of the lateral hypothalamic area (LHAs). A redistribution of orexin from the perinuclear space to the processes of these cells took place, which occurs after the activation and the expression of the c-fos-gene. c-Fos protein was expressed in most neurons with minimum content of orexin, i.e. activation of these neurons correlated with the redistribution of orexins caused by skin EHF-irradiation and injection of cyclophosphamide (CPA). EHF-irradiation of the skin before and after injection of CPA increased the staining of orexin-containing neurons, i.e. it prevented the redistribution of orexin.

[Expression of c-Fos gene in the rat hypothalamus upon electric painful stimulation and EHF irradiation of the skin].

Studies of the activation pattern of hypothalamic cells upon electric painful stimulation have revealed an increase in the counts of c-Fos-positive cells (72.02-98.95%) predominantly of a size ranging from 10 to 50 microm2. EHF irradiation of the skin activates hypothalamic cells of the size ranging from 10 to 70 microm2 in the paraventricular, dorsomedial nuclei, and in perifonical zone of the lateral hypothalamic area. The combined action of EHF skin irradiation and electric painful stimulation leads to a decrease in the counts of cells activated in result of the painful stimulation in the anterior hypothalamic area, ventromedial nucleus, and the basal part of the lateral area. Changes in size distributions of activated cells are found in the ventromedial nucleus and the basal part of the lateral area, occur mainly through decreased counts of smaller cells (10-30 microm2) and increased counts of lager cells. The modulatory effect of EHF irradiation of the skin was found to be expressed as a reduction in hypothalamic cell activation caused by electric painful stimulation.

Expression of the c-Fos gene in hypothalamic cells and cytotoxic activity of natural killer cells in the spleen of rats after treatment with Cytoxan.

In experiments on rats we studied the effect of cyclophosphamide-containing drug Cytoxan on activation of neurons in hypothalamic structures involved in the regulation of natural killer cell activity in the spleen and changes in cytotoxicity of these cells. Administration of Cytoxan in a dose of 60 mg/kg increased the number of c-Fos-positive cells in the ventromedial hypothalamus and lateral hypothalamic area and reduced interferon-alpha-induced cytotoxic activity of natural killer cells. Our findings attest to the involvement of central mechanisms of regulation of splenic natural killer cells into side effects of Cytoxan.

[Structure and functions of the brain orexin-containing neurons].

The results of investigations of the new discovered brain orexin neurons, their chemical structure, localization and functions are reviewed. The following data are described: the specifics of orexins mRNA, orexins A and B and their receptors; connections between orexin neurons and neurons from different structures of the brain and spinal cord and the participation of the orexin neuron system in the functional regulation.

[Clinical, x-ray, and laboratory features of tuberculosis and osteomyelitis of the spine].

In 20% of cases, tuberculous spondylitis running with a prevalence of the exudative-necrotic type of a local tissue reaction has an acute onset with febrile fever, severe pains, and progressive neurological disorders and clinically resembles acute hematogenous osteomyelitis of the spine. With a predominance of the productive type of a tissue reaction, tuberculous spondylitis resembles subacute hematogenous osteomyelitis of the spine. History data, laboratory parameters, and an X-ray follow-up are of great importance in its differential diagnosis.

[Stress-induced changes of hypothalamic structure cell responses to antigen injection (LPS) (revealed by c-Fos protein expression)].

Stress stimuli are known to influence the intensity if immune response. To elucidate the role of central regulating structures in this changes, analysis of activation level of hypothalamic neurons (revealed by quantity of c-Fos-positive cells) was carried out in rats within 2 hours after intravenous LPS injection and after this--impact associated with electric pain stimulation (EPS). The investigation was carried out in 52 male Wistar rats, 200-250 g. The c-Fos protein expression was analyzed with immunohistochemical method. The increase of c-Fos-positive cells number in 2 hours after LPS injection was observed in AFTN, PVH, LHA, VMH, DMH and PH. After electrical pain stimulation, the quantity of c-Fos-positive cells increased in the same structures. Combined application of electric pain stimulation and LPS injection results in diminished activation level in AHN, PVH, LHA and VMH as compared with typical response to single LPS injection without EPS. The EPS suppresses intensity of the immune response induced by injection of LPS (revealed by local hemolysis method with calculation of antibody-forming cells quantity (%) in the rat spleen). Thus the activation level changes of hypothalamic structures (AHN, PVH, LHA, PH) correlate with development of stress-induced immunosuppression, i. e. morphofunctional description of hypothalamic structures activation as revealed by pattern of activated cell alterations in hypothalamic structures during realization of stress-induced changes of immune system responses to antigen injection.

[c-FOS protein expression in cells of the variuos hypothalamic structures after electric pain stimulation and injections of antigens].

Hypothalamic structures become activated after stimul. Alteration of c-Fos-positive cells quantity in different hypothalamic structures after electric pain stimulation (EPS), intravenous (iv) injection of antigens (lioppolysaccharide (LPS) and bovine serum albumir (BSA)) was detected with immunohistochemical method. EPS and iv injection of antigens (LPS and BSA) result in c-Fos-positive cells quantity increase in all observed hypothalamic structures. The highest activation level was in AHN and PH after EPS and in AHN, PVH, LHA-28, and PH after iv LPS injection. Comparative analysis of results showed, that c-Fos-positive cells quantity increase after EPS in AHN, PVH, LHA and PH was more significant than after iv injection of antigens (LPS and BSA). LPS injection results in more pronounced cell activation in AHN, PVH, LHA-28 and DMH (according to quantity of c-Fos-positive cells), than BSA injection.