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The aim of this study was to determine the relationships in the microbial trophic network underpinning them about communities of plankton ciliates in shallow oxbow lakes of the Vistula River in southern Poland (Jeziorzany 1, Jeziorzany 2, Piekary, Tyniec). The plankton components (phytoplankton, ciliates, zooplankton) were grouped by dietary preference. The studied oxbows differed in physicochemical parameters and in phytoplankton. Cyanobacteria dominated in the total biomass of phytoplankton in the Tyniec oxbow, big green algae (>30 µm) in Piekary and Jeziorzany 1, and euglenoids in Jeziorzany 2 oxbow. The dominance pattern of ciliates and zooplankton were similar in all oxbows. Algivorous ciliates were the main dominant ciliates, and among zooplankton the dominant ones were herbivores that feed on small algae (<30 µm). The oxbows differed significantly in total phytoplankton biomass, cyanobacteria biomass, euglenoid biomass, small green algae (<30 µm) biomass, total biomass of zooplankton, biomass of zooplankton feeding on bacteria + algae, and biomass of zooplankton feeding on big algae (>30 µm). There was no significant differences in ciliate biomass between oxbows. In redundancy analyses, the variability at the trophic groups of plankton was described by explanatory variables in 42.3 %, and positive relationships were found: e.g., between omnivorous zooplankton biomass, the biomass of ciliates feeding on bacteria + algae, and NH4 level; between euglenoid biomass and dinoflagellate biomass; and between cyanobacteria biomass and bacterivorous ciliate biomass. Spearman correlation analysis revealed several relationships between different groups of plankton. In general, phytoplankton group shows more connection among themselves and with different zooplankton groups, e.g., phytoplankton biomass with herbivorous zooplankton biomass (-0.33); and cyanobacteria biomass with dinoflagellate biomass (0.65). Ciliates showed more connections among their trophic groups (e.g., algivorous ciliate biomass with omnivorous ciliate biomass, 0.78) and with zooplankton trophic groups (e.g., biomass of algivorous + bacterivorous ciliates with biomass of predator zooplankton, -0.36). Simple correlations analysis revealed the trophic food web network connectivity among plankton organisms, indicating the flow of organic matter from phytoplankton to zooplankton and from ciliates to zooplankton. Our study sheds light on the trophic relations among plankton ciliates, which are neglected in research but often form a large percentage of zooplankton biomass. In the studied oxbows, ciliate forms 6.7 % of total zooplankton biomass in Jeziorzany 1 and up to 44.5 % of it in the Piekary oxbow.

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The ability of the specific immune response of organisms is determined by the possibility of synthesis, transport and presentation of the major histocompatibility complex class II (MHC II) molecules on the surface of antigen-presenting cells. MHC II molecules are responsible for the binding, transport and presentation of a foreign antigen to helper T lymphocytes. They also stimulate the multiplication of specific B lymphocytes and determine the type of antibodies produced. The expression of MHC II molecules on the cellular surface of the spinal cord in cervical, thoracic, lumbar and sacral regions was studied on 30 normal human foetuses between 11 and 22 weeks of gestation (GW) and 9 foetuses with genetic defects (Down syndrome, mucopolysaccharidosis, mucoviscidosis or Nori's syndrome) between 17 and 22 GW. The immunocytochemical presence of MHC II molecules was found in all regions of the spinal cord in both groups of foetuses, normal and pathological, during the whole interval under study. The molecules were dispersed in the grey and white matter of the spinal cord and located most frequently on the surface of cells, near the central canal and blood vessels. These cells corresponded morphologically and immunocytochemically with amoeboid and ramified microglia. No differences in MHC II expression between the spinal cord regions or between normal foetuses and those with genetic defects were noted. It seems likely that such an early occurrence of MHC II expression in the spinal cord of foetuses with normal development, as well as the absence of abnormalities in this expression in foetuses with genetic defects, may indicate the significant role of these molecules in the immunological protection of the foetus and thus ensuring normal embryogenesis.

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Immunohistochemistry (IHC) and ultrastructural study were performed on 19 demented autopsy cases of sporadic Alzheimer's disease (AD). Semiquantitative IHC assessment of the pathological changes, according to the criteria of the Consortium to Establish a Registry of Alzheimer's Disease (CERAD) and the Consortium on Dementia with Lewy Bodies, showed morphological hallmarks of AD in 18 demented patients. It was found that 11 of these cases fulfilled criteria for "pure" AD, whereas the remaining 7 cases, with mixed findings, Lewy bodies (LBs) and Lewy-related dystrophic neurites, neuritic plaques (NP) and sometimes neurofibrillary tangles (NFT), met the criteria for Lewy body variant of Alzheimer's disease (LBV). One case with brain stem and cortical LBs but without NP and NFT was finally diagnosed as a pure form of dementia with Lewy bodies (DLB). Regional distribution and semiquantitative assessment frequency of alpha-synuclein-immunoreactive LBs, tau-immunoreactive NFT and beta-amyloid immunoreactive senile plaques, were compared between LBVand AD. Ultrastructural examination confirmed the filamental structure of cortical LBs. In conclusion, IHC study including antibody to alpha-synuclein, the sensitive marker for Lewy bodies, revealed the coexistence of brain stem and cortical LBs and pathological features of AD in a great part of dementia cases. Patients with mixed, LBs, NP and sometimes NFT pathology, fulfilled neuropathological CERAD criteria for LBV. Semiquantitative comparative IHC study, according to LBs- and NFT-scores and CERAD NP-scores showed in the LBV group a significantly lower frequency of NFT coexisting with neocortical LBs than in the group with pure form of AD.

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The quantitative correlation between neurone loss and brain immune response, assessed by intensity of microglia inflammatory reaction in cortical association area and limbic cortex, was investigated and compared in previously immunohistochemistry (IHC) and ultrastructural confirmed 11 cases of Alzheimer's disease (AD), 7 cases mixed form of Dementia with AD findings and Lewy bodies (AD/DLB) reported, in accordance with Consortium on Dementia, as Lewy body variant of AD (LBV) and 6 non-demented autopsy control cases from 63 to 86 years old. In the present work we investigated association and limbic cortical areas linked with memory mechanisms; there are regions characterised by early distribution of IHC confirmed AD and DLB/AD (LBV) markers, as well as a substantial physiological stability of neurone pool regardless of age. The results indicated that AD and LBV differ in their neurone loss intensity and inflammatory reaction, with much higher intensity in AD. In Alzheimer's disease, neurone loss in association temporal cortex made up 51% of control values with simultaneous 8-fold increase in the density of MHC II-positive activated microglia, whereas in LBV, both the loss of neurone density and the increase in activated microglia density, was not so high (up to 41% and 4-5-fold, respectively). Changes in the limbic cortex were less pronounced. A strong correlation in the clinical material between neurone loss and microglia activation in both processes, especially in AD (r = 0.73), speaks in favour of the hypothesis on the neuronal immune surveillance and arousal of immune brain response in conditions of declining control, due to significant neurone loss in the neurodegenerative process. The inflammatory reaction of MHC II-immunoreactive microglia, concomitant with neurodegenerative process, seems to be a consequence of increased immune response due to loss of neurones and weakening of their control upon immunosurveillance in central nervous system.

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Antigen-presenting cells (APCs) that show the expression of major histocompatibility complex (MHC) class II molecules in adult persons are related to an early phase of immunological response. These molecules are responsible for the binding, transport, and presentation of a foreign antigen to helper T lymphocytes and determine the type of antibodies produced. They also stimulate the multiplication of specific B lymphocytes and participate in the elimination of autoreactive lymphocytes and maturation of T lymphocytes. Cells with MHC II molecules expressed on their surface were observed in the frontal and temporal lobes of 30 brains of human fetuses with normal development between gestation weeks (GW) 11 and 22. MHC II expression was noted during the whole interval under study. Its immunocytochemical localization was noted on the surface of the cerebral meninges cells, in the choroid plexus of the lateral ventricle and blood vessel lumen, and in ameboid microglia (AM) and ramified microglia (RM) cells in both cerebral lobes of the human fetus. The expression of MHC II that occurred on the cells of the central nervous system (CNS) already in GW 11 may be evidence not only of an early capability of immunological protection of the fetal nervous system, but also of a significant role potentially played by this system in normal embryogenesis. Despite continuous controversy over the cellular lineage of microglia origin, the expression of MHC II on AM and RM cells indicates its mesodermal origin, as in other APCs.

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In adults, under physiological conditions proteins of the major histocompatibility complex, class II (MHC II) molecules are synthesized and then presented on the surface of the cells known under a common name as antigen presenting cells (APCs). Dendritic cells (DCs), microglia, macrophages, ameboid microglia and lymphocytes B are qualified as APCs. The aim of present study was to evaluate the expression of MHC II molecules in the central nervous system (CNS) and hematopoietic organs during the fetal development. Observations were made on the cerebral occipital lobe, cerebellum, thymus, spleen and liver of 30 normal human fetuses, between 11 and 22 week of gestation (GW). Histological, histochemical and immunohistochemical techniques were used to identify cells with expression of MHC II molecules. In the brain, MHC II molecules were detected on macrophages/ameboid microglia in meninges, choroid plexus and single cells of ramified microglia in deeper layers of the cortex and white matter. In the other organs besides macrophages and dendritic cells, MHC II molecules were also immunopositive in thymic epithelial cells, and in the spleen and liver also in other cells of stroma and lobule. The expression of MHC II molecules on so extensive population of cells, at an early stage of the fetal development, may evidence their significant involvement in histogenesis and morphogenesis. It seems that in adults the complex of MHC II with protein is originated from the foreign antigen. On the contrary, during normal fetal development the complex of MHC II with protein origins most probably from the fetus own structures.

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Ganglioglioma is a tumor composed of neoplastic neurons and neoplastic glial cells mixed in different proportions. Astrocytes are the essential glial component. The tumor proliferates mostly in the temporal lobe cortex, scarcely in other areas of the brain. In ganglioglioma the population of ganglionic neurons is very difficult to diagnose. In the last ten years, immunocytochemical reaction with synaptophysin and neurofilament protein (NFP) triad considered as neoplastic neuron markers seemed to differentiate neoplastic nerve cells from normal neurons occurring incidentally within neoplastic proliferation area. In our study, the reaction with synaptophysin and NFP was performed on fragments of normal frontal lobe, pons and cerebellum as well as on fragments of post-operation tumor diagnosed as ganglioglioma. A positive synaptophysin reaction was obtained on the surface of neoplastic neurons in gangliogliomas, as well as on the surface of normal neurons in the encephalon, cerebellum and pons. Both neoplastic and normal neurons and their processes showed the expression of neurofilaments protein triad. Thus, a positive reaction of neurons with synaptophysin and NFP seems to be nonpathognomic in the diagnosis of the neoplastic neuron population in gangliogliomas.

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Two archival cases diagnosed 20 years ago on routine neuropathological methods as Encephalitis Necroticans Acuta (ENA) were investigated in EM and by immunohistochemical methods. The previous diagnosis was confirmed only in one case because Herpes simplex virus was found. In the second case the intracellular inclusions visible in ME corresponded to Measles Virus thus previous diagnosis was changed to SSPE.

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The study was performed on the tissues derived from the central nervous system (CNS) of 72 normal human fetuses between 8 and 22 week of gestation (GW) and 30 fetuses with genetically confirmed Down's syndrome between 17 and 22 GW. Histochemical, immunocytochemical and ultrastructural examinations of microglial cells in frontal lobe, mesencephalon and cerebellum were carried out. A quantitative evaluation of developing microglia was performed in comparison with astroglial cells by counting the mean number of cells per 1 mm2. The study indicated that microglial cells emerge at the same time in all structures under study, both in normal fetuses and in those with Down's syndrome. It was also found that ameboid microglia (AM) and ramified microglia (RM) emerge at the same time and show the same morphological structure in both groups of fetuses. It was revealed that in the CNS of fetuses with Down's syndrome, the number of ramified microglial cells increased significantly as compared with in normal fetuses. Astroglial cells outnumbered microglial cells in the normal fetal development. Due to the enhanced number of RM cells in the CNS of fetuses with Down's syndrome the quantitative difference between these cells obliterated, and microglial cells in the frontal lobe cortex even outnumbered astroglial cells.

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The aim of the study was to find out whether differences in morphology and time-sequence of microglia appearance in course of development of the phylogenetically different structures of the central nervous system (CNS) in normal human fetus do exist. An attempt was also made to evaluate quantitatively the development of microglial cells in comparison to astroglia, taking into account their role in the structural and immunological maturation of the CNS. The study was performed on CNS tissue of frontal lobes, mesencephalon and cerebellum from 72 fetuses between 8 and 22 week of gestation (GW). Histochemical and immunohistochemical reactions were used as basic study methods. A quantitative evaluation of developing microglia and astroglia in all investigated structures was performed by counting the mean number of cells per 1 mm2. Morphological and ultrastructural patterns of the three basic types of microglia; ameboid, ramified active and ramified resting, were characterized. It was indicated that they emerge at the same time in all structures under study, except the ameboid microglia arising earlier in the mesencephalon. A quantitative evaluation revealed that the number of ameboid microglial cells decreased slightly in an early stage of fetal development. The number of ramified microglial cells between 11 and 22 GW increased in all structures. The highest values of ramified microglia were found in mesencephalon, and the lowest in white matter of cerebellum. The number of astroglial cells exceeded the increase in ramified microglia by several times in all structures.

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To assess the cytogenesis and the structure of the microglial cells, we studied mesencephalons in 47 human fetuses at 7th-40th week of gestational age, and in 18 adult brains from 20 to 70 years. The microglial cells were identified and characterized by morphological criteria using immunohistochemical and histochemical techniques. As early as in the 8th week of gestational age RCA-1 positive cells were detected, mainly in form of amoeboid microglial cells. These microglial cells were observed around the germinal matrix, and at or near the wall of blood vessels. RCA-1 positive cells which were detected within leptomeninges were large but without processes. At the 16th-40th week of gestational age we observed in mesencephalon, amoeboid microglial cells, and also RCA-1 positive and ferritin reactive ramified microglial cells.

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