Neurotrophins in the developing and adult rat visual system: In vivo and in vitro studies

In vivo anatomical studies were performed with the aim of clarifying the cellular and subcellular distribution and the developmental pattern of expression of brain-derived neurotrophic factor (BDNF), neurotrophin-4 (NT-4), neurotrophin-3 (NT-3) and their receptors, trkB and trkC in the rat visual pathway. BDNF and trkB proteins were expressed in developmentally regulated patterns in most visual centres including the lateral geniculate nucleus (LGN), superior colliculus (SC), and the visual cortex. With some exceptions, BDNF and trkB mRNA expression patterns in visual centres were similar to those of their proteins; however in some visual centres, BDNF mRNA expression was not detected, but BDNF protein was restricted to neuropil. The expression of NT-4, NT-3 and trkC mRNAs was limited to neurons in the SC and visual cortex. By pre-embedding electron microscopy, BDNF was predominantly located in retinal terminals and trkB at the apposing postsynaptic densities and associated with axonal and dendrite microtubules. BDNF and trkB proteins, their mRNAs and NT-4 mRNA (but not NT-3 or trkC) were present in developing and adult retinal ganglion cells (RGCs). Retinal explant cultures were used to study the effects of neurotrophins on developing and regenerating RGC axons. BDNF and NT-4, but not NT-3 protein, significantly increased the outgrowth (number and length) of regenerating RGC axons and RGC axons at El5, and to a lesser extent at later embryonic stages. BDNF and NT- 4, but not NT-3 protein, increased the intensity of -III tubulin, F-actin and GAP-43 immunoreaction product in RGC axons and growth cones. Treatment with TrkB-IgG arrested RGC axon outgrowth, induced growth cone collapse and resulted in the loss of F-actin in the P-domain of RGC axonal growth cones. The expression pattern of trkB and BDNF mRNAs during development and in adulthood and the effects of BDNF in vitro suggest that BDNF plays important roles in visual system maturation and maintenance. The lack of neurotrophin expression in some retinorecipient centres but the localisation of BDNF protein in retinal terminals suggests that BDNF anterogradely transported from RGCs may exert important effects on their central targets

Geochemical composition, mineralogy, geotechnical characteristics of some clay deposits in parts of the southern Niger Delta, Nigeria

Clay soil samples from the Afo-Okpella and Okpekpe in parts of the southern Niger Delta were analyzed for their geochemical composition, mineralogical and geotechnical characteristics. X-ray fluorescence analysis, x-ray diffraction analysis and index property tests were carried out to determine elemental composition, mineralogical nature and geotechnical attributes of the clay. The XRF reveals that SiO2 and Al2O3 are the predominant oxides. The XRD analysis shows that kaolinite is the predominant clay mineral with varying amount of quartz also traces of illite, smectite. The geotechnical index test shows that the clay soil samples studied also contains considerable amounts of silt-size particles (18%-70%) which makes them unsuitable in their raw state for use as fillers, raw materials in the paint industries. The clays were generally of medium to high plasticity and medium to high compressibility, however the classification of degree of expansion as regard to percentage linear shrinkage places the entire clay bodies studied in the critical degree of expansion. The study reveals that they are good for the production of quality bricks, ceramics and other industrial usage such as rubber, paper and paint industries

Lithofacies Characterization and Quantitative Mineralogical Analysis of the sediments from Sahaiawei-1Well in the Northern Delta Depobelt of the Niger Delta Basin

The sediments of Sahaiawei-1 Well in the Northern Delta Depobelt are represented by sand and shale alternation. Lithofacies characterization and X-ray diffraction technique were used to characterize the sediments from the well in order to characterize the lithofacies, identify the minerals present, determine environment of deposition and identify potential zones for hydrocarbon exploitation. The lithofacies characterization was based on the textural properties, mineralogical composition, fossil content, homogeneity and heterogeneity of the lithofacies units of the well. The lithofacies analysis for Sahaiawei-1 Well identified four (4) lithofacies types of mainly sandstone, shaly sandstone, sandy shale and shale; and fourteen (14) lithofacies zones. The result of the X-ray diffraction analysis identified the following clay minerals \u2013 kaolinite, illite/muscovite, chlorite and sepiolite; carbonates and non-clay minerals. Therefore, due to the high percentage of kaolinite in Sahaiawei-1 Well (2% to 39.87%), it could be concluded that pore filing kaolinite may have more effect on the reservoir quality than the pore bridging illite and pore lining chlorite

Transplanted human adipose tissue-derived stem cells engraft and induce regeneration in mice olfactory neuroepithelium in response to dichlobenil subministration

We used immunodeficient mice, whose dorsomedial olfactory region was permanently damaged by dichlobenil inoculation, to test the neuroregenerative properties of transplanted human adipose tissue-derived stem cells after 30 and 60 days. Analysis of polymerase chain reaction bands revealed that stem cells preferentially engrafted in the lesioned olfactory epithelium compared with undamaged mucosa of untreated transplanted mice. Although basal cell proliferation in untransplanted lesioned mice did not give rise to neuronal cells in the olfactory mucosa, we observed clusters of differentiating olfactory cells in transplanted mice. After 30 days, and even more at 60 days, epithelial thickness was partially recovered to normal values, as also the immunohistochemical properties. Functional reactivity to odorant stimulation was also confirmed through electroolfactogram recording in the dorsomedial epithelium. Furthermore, we demonstrated that engrafted stem cells fused with mouse cells in the olfactory organ, even if heterokaryons detected were too rare to hypothesize they directly repopulated the lesioned epithelium. The data reported prove that the migrating transplanted stem cells were able to induce a neuroregenerative process in a specific lesioned sensory area, enforcing the perspective that they could become an available tool for stem cell therapy. \ua9 The Author 2014. Published by Oxford University Press. All rights reserved

Modulators of Cytoskeletal Reorganization in CA1 Hippocampal Neurons Show Increased Expression in Patients at Mid-Stage Alzheimer's Disease

During the progression of Alzheimer's disease (AD), hippocampal neurons undergo cytoskeletal reorganization, resulting in degenerative as well as regenerative changes. As neurofibrillary tangles form and dystrophic neurites appear, sprouting neuronal processes with growth cones emerge. Actin and tubulin are indispensable for normal neurite development and regenerative responses to injury and neurodegenerative stimuli. We have previously shown that actin capping protein beta2 subunit, Capzb2, binds tubulin and, in the presence of tau, affects microtubule polymerization necessary for neurite outgrowth and normal growth cone morphology. Accordingly, Capzb2 silencing in hippocampal neurons resulted in short, dystrophic neurites, seen in neurodegenerative diseases including AD. Here we demonstrate the statistically significant increase in the Capzb2 expression in the postmortem hippocampi in persons at mid-stage, Braak and Braak stage (BB) III-IV, non-familial AD in comparison to controls. The dynamics of Capzb2 expression in progressive AD stages cannot be attributed to reactive astrocytosis. Moreover, the increased expression of Capzb2 mRNA in CA1 pyramidal neurons in AD BB III-IV is accompanied by an increased mRNA expression of brain derived neurotrophic factor (BDNF) receptor tyrosine kinase B (TrkB), mediator of synaptic plasticity in hippocampal neurons. Thus, the up-regulation of Capzb2 and TrkB may reflect cytoskeletal reorganization and/or regenerative response occurring in hippocampal CA1 neurons at a specific stage of AD progression

Lithofacies characterization and quantitative mineralogical analysis of the sediments from Sahaiawei-1well in the northern Delta Depobelt of the Niger Delta Basin

The sediments of Sahaiawei-1 Well in the Northern Delta Depobelt are represented by sand and shale alternation. Lithofacies characterization and X-ray diffraction technique were used to characterize the sediments from the well in order to characterize the lithofacies, identify the minerals present, determine environment of deposition and identify potential zones for hydrocarbon exploitation. The lithofacies characterization was based on the textural properties, mineralogical composition, fossil content, homogeneity and heterogeneity of the lithofacies units of the well. The lithofacies analysis for Sahaiawei-1 Well identified four (4) lithofacies types of mainly sandstone, shaly sandstone, sandy shale and shale; and fourteen (14) lithofacies zones. The result of the X-ray diffraction analysis identified the following clay minerals – kaolinite, illite/muscovite, chlorite and sepiolite; carbonates and non-clay minerals. Therefore, due to the high percentage of kaolinite in Sahaiawei-1 Well (2% to 39.87%), it could be concluded that pore filing kaolinite may have more effect on the reservoir quality than the pore bridging illite and pore lining chlorite. Keywords: alternation, lithofacies, X-ray diffraction, reservoir, mineralog

BDNF and its pro-peptide are stored in presynaptic dense core vesicles in brain neurons

Although brain-derived neurotrophic factor (BDNF) regulates numerous and complex biological processes including memory retention, its extremely low levels in the mature central nervous system have greatly complicated attempts to reliably localize it. Using rigorous specificity controls, we found that antibodies reacting either with BDNF or its pro-peptide both stained large dense core vesicles in excitatory presynaptic terminals of the adult mouse hippocampus. Both moieties were ?10-fold more abundant than pro-BDNF. The lack of postsynaptic localization was confirmed in Bassoon mutants, a seizure-prone mouse line exhibiting markedly elevated levels of BDNF. These findings challenge previous conclusions based on work with cultured neurons, which suggested activity-dependent dendritic synthesis and release of BDNF. They instead provide an ultrastructural basis for an anterograde mode of action of BDNF, contrasting with the long-established retrograde model derived from experiments with nerve growth factor in the peripheral nervous system