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See detailNeuroimmune connections in ovine pharyngeal tonsil: potential site for prion neuroinvasion
Toppets, Vinciane ULg; Piret, Joëlle ULg; Kirschvink, Nathalie et al

in Cell & Tissue Research (2012)

Recent studies have proved the possible implication of nasal associated lymphoid tissues, mainly the pharyngeal tonsil, in prion pathogenesis. However, the mechanisms of this neuroinvasion are still being ... [more ▼]

Recent studies have proved the possible implication of nasal associated lymphoid tissues, mainly the pharyngeal tonsil, in prion pathogenesis. However, the mechanisms of this neuroinvasion are still being debated. To determine the potential sites for prion neuroinvasion inside the ovine pharyngeal tonsil, the topography of neurofilaments heavy (200 kDa) (NFH), neurofilaments light (70 kDa) (NFL) and glial fibrillar acidic protein (GFAP) was semi-quantitatively analysed inside the different compartments of the tonsil. The results showed that the most innervated areas were the interfollicular area and the connective tissue located beneath the respiratory epithelium. Even if the germinal centre of the lymphoid follicles was poorly innervated, the existence of rare follicular dendritic cell-nerve synapses inside the germinal centre indicates that this mechanism of neuroinvasion is possible but unlikely to be unique. The host PRNP genotype did not influence the pattern of innervation in these different tonsil compartments, unlike age: an increase of nerve endings in a zone of high trafficking cells beneath the respiratory epithelium occurred with ageing. A minimal age-related increase of innervation inside the lymphoid follicles was also observed. An increase in nerve fibre density around the lymphoid follicles, in an area rich in mobile cells able to transport PrPd, could ensure a more efficient infectivity, not in the early phase but in the advanced phase of lymphoinvasion after amplification of PrPd, or could act as direct site of entry during neuroinvasion. [less ▲]

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See detailEarly identification of inner pillar cells during rat cochlear development.
Thelen, Nicolas ULg; Breuskin, Ingrid ULg; Malgrange, Brigitte ULg et al

in Cell & Tissue Research (2009), 337(1), 1-14

Although the structure of the auditory organ in mature mammals, the organ of Corti, is clearly established, its development is far from being elucidated. Here, we examine its spatio-temporal development ... [more ▼]

Although the structure of the auditory organ in mature mammals, the organ of Corti, is clearly established, its development is far from being elucidated. Here, we examine its spatio-temporal development in rats from embryonic day 16 (E16) to E19 by using cytochemical and immunocytochemical methods at the light- and electron-microscope levels. We demonstrate that the organ of Corti develops from a non-proliferating cell zone that is located in the junctional region between two edges of the dorsal epithelium of the cochlear duct. We also reveal that the first cells to develop in this zone are the inner pillar cells, a particular type of non-sensory supporting cell, which arise in the base of the cochlear duct at the boundary between the two ridges at E16. Cell differentiation in this prosensory region continues according to a base-to-apex gradient; the inner hair cells appear in the greater epithelial ridge at E17 and the outer hair cells in the lesser epithelial ridge at E18. At E19, the various cell types of the organ of Corti are in place. Finally, we show that unlike the development of all the supporting cell types of the organ of Corti, the development of inner pillar cells within the prosensory domain seems not to involve Notch1 activation. These results highlight the central role that the inner pillar cells probably play in the development of the organ of Corti. [less ▲]

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See detailThe rocker bone: a new kind of mineralised tissue?
Parmentier, Eric ULg; Compère, Philippe ULg; Casadevall, Margarida et al

in Cell & Tissue Research (2008), 334

In some Ophidiiform fishes, the anterior part of the swimbladder is thickened into a hard structure called the “rocker bone”, which is thought to play a role in sound production. Although this structure ... [more ▼]

In some Ophidiiform fishes, the anterior part of the swimbladder is thickened into a hard structure called the “rocker bone”, which is thought to play a role in sound production. Although this structure has been described as cartilage or bone, its nature is still unknown. We have made a thorough analysis of the rocker bone in Ophidion barbatum and compared it with both classical bone and cartilage. The rocker bone appears to be a new example of mineralisation. It consists of (1) a ground substance mainly composed of proteoglycans (mucopolysaccharide acid) and fibres and (2) a matrix containing small mineralised spherules composed of a bioapatite and fibrils. These spherules are embedded in mineralised cement of a similar composition to the spherules themselves. The rocker bone grows via the apposition of new apatite spherules at its periphery. These spherules are first secreted by the innermost fibroblast layer of the capsule contained in the rocker bone and then grow extracellularly. Blood vessels, which represent the only means of transport for matrix and mineral material, are numerous. They enter the rocker bone via the hyle and ramify towards the capsule. We propose to call this new kind of mineralised tissue constituting the rocker bone “frigolite” (the Belgian name for styrofoam) in reference to the presence of spherules of different sizes and the peculiarity of the rocker bone in presenting a smooth surface when fractured. [less ▲]

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See detailNeuroimmune connections in jejunal and ileal Peyer's patches at various bovine ages: potential sites for prion neuroinvasion
Defaweux, Valérie ULg; Dorban, Gauthier ULg; Antoine, Nadine ULg et al

in Cell & Tissue Research (2007), 329(1), 35-44

During preclinical stages of cattle orally infected with bovine spongiform encephalopathy (BSE), the responsible agent is confined to ileal Peyer's patches (IPP), namely in nerve fibers and in lymph ... [more ▼]

During preclinical stages of cattle orally infected with bovine spongiform encephalopathy (BSE), the responsible agent is confined to ileal Peyer's patches (IPP), namely in nerve fibers and in lymph follicles, before reaching the peripheral and central nervous systems. No infectivity has been reported in other bovine lymphoid organs, including jejunal Peyer's patches (JPP). To determine the potential sites for prion neuroinvasion in IPP, we analyzed the mucosal innervation and the interface between nerve fibers and follicular dendritic cells (FDC), two dramatic influences on neuroinvasion. Bovine IPP were studied at three ages, viz., newborn calves, calves less than 12 months old, and bovines older than 24 months, and the parameters obtained were compared with those of JPP. No differences in innervation patterns between IPP and JPP were found. The major difference observed was that, in calves of less than 12 months, IPP were the major mucosal-associated lymphoid organ that possessed a large number of follicles with extended FDC networks. Using a panel of antibodies, we showed that PP in 24-month-old bovines were highly innervated at various strategic sites assumed to be involved in the invasion and replication of the BSE pathogen: the suprafollicular dome, T cell area, and germinal centers. In PP in calves of less than 12 months old, no nerve fibers positive for the neurofilament markers NF-L (70 kDa) and NF-H (200 kDa) were observed in contact with FDC. Thus, in view of the proportion of these protein subunits present in neurofilaments, the innervation of the germinal centers can be said to be an age-dependent dynamic process. This variation in innervation might influence the path of neuroinvasion and, thus, the susceptibility of bovines to the BSE agent. [less ▲]

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See detailCloning of the prepro C-RFa gene and brain localization of the active peptide in Salmo salar
Montefusco-Siegmund, R. A.; Romero, A.; Kausel, G. et al

in Cell & Tissue Research (2006), 325(2), 277-285

In all vertebrates, the synthesis and release of prolactin (Prl) from pituitary lactotroph cells is tightly controlled by hypothalamic factors. We have cloned and characterized a hypothalamic cDNA from ... [more ▼]

In all vertebrates, the synthesis and release of prolactin (Prl) from pituitary lactotroph cells is tightly controlled by hypothalamic factors. We have cloned and characterized a hypothalamic cDNA from Atlantic salmon (Salmo salar) encoding C-RFa, a peptide structurally related to mammalian Prl-releasing peptide (PrRP). The deduced preprohormone precursor is composed of 155 amino acid residues presenting a 87.1% similarity to chum salmon C-RFa and a 100% similarity to all fish C-RFa in the bioactive precursor motifs. C-RFa-immunoreactive perikarya and fibres were located in the brain of S. salar, especially in the hypothalamus, olfactory tract, optic tectum and cerebellum. In contrast, immunolabelled fibres were not observed in the pituitary stalk or in the hypophysis. However, interestingly, we detected immunolabelled cells in the rostral pars distalis of the pituitary in the basolateral region in which Prl is synthesized. These results were confirmed by obtaining a strong signal by using reverse transcription/polymerase chain reaction (RTPCR) on mRNA from both hypothalamus and pituitary. These data show, for the first time, by immunohistochemistry and RT-PCR, that C-RFa is produced in pituitary cells. Finally, based on these results, a possible function for CRFa as a locally produced PrRP in this teleost is discussed. [less ▲]

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See detailOverexpression of TIMP-1 under the MMP-9 promoter interferes with wound healing in transgenic mice
Salonurmi, T.; Parikka, M.; Kontusaari, S. et al

in Cell & Tissue Research (2004), 315(1), 27-37

We have generated transgenic mice harboring the murine matrix metalloproteinase 9 (MMP-9) promoter cloned in front of human TIMP-1 cDNA. The transgenic mice were viable and fertile and exhibited normal ... [more ▼]

We have generated transgenic mice harboring the murine matrix metalloproteinase 9 (MMP-9) promoter cloned in front of human TIMP-1 cDNA. The transgenic mice were viable and fertile and exhibited normal growth and general development. During wound healing the mice were shown to express human TIMP-1 in keratinocytes that normally express MMP-9. However, the healing of skin wounds was significantly retarded with slow migration of keratinocytes over the wound in transgenic mice. In situ zymography carried out on wound tissues revealed total blockage of gelatinolytic activity (i.e., MMP-9 and MMP-2). The results confirm studies with MMP-9 knockout mice showing that MMP-9 is not essential for general development, but they also demonstrate an important role of keratinocyte MMP-9, as well that of other keratinocyte MMPs that are inhibited by TIMP-1, in wound healing. The transgenic mice generated in this study provide a model for the role of MMPs in MMP-9-producing cells in other challenging situations such as bone fracture recovery and cancer invasion. [less ▲]

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See detailEffects of testosterone on Reelin expression in the brain of male European starlings
Absil, Philippe ULg; Pinxten, R.; Balthazart, Jacques ULg et al

in Cell & Tissue Research (2003), 312(1), 81-93

Reelin, a large glycoprotein defective in reeler mice, is assumed to determine the final location of migrating neurons in the developing brain. We studied the expression of Reelin in the brain of adult ... [more ▼]

Reelin, a large glycoprotein defective in reeler mice, is assumed to determine the final location of migrating neurons in the developing brain. We studied the expression of Reelin in the brain of adult male European starlings that had been treated or not with exogenous testosterone. Reelin-immunoreactive cells and fibers were widely distributed in the forebrain including areas in and around the song control nucleus, HVC. No labeling was detected in other song control nuclei with the exception of nucleus uvaeformis, which was delineated by a dense cluster of Reelin-immunoreactive perikarya. Reelin is thus expressed in areas incorporating new neurons in adulthood, such as HVC. Reelin expression was sharply decreased by testosterone in HVC, nucleus uvaeformis and dorsal thalamus but not in other brain regions. These results are consistent with the idea that seasonal changes in Reelin expression modulate the incorporation of neurons within HVC. The presence of Reelin in other brain areas that do not incorporate new neurons in adulthood indicates, however, that this protein must play other unrelated roles in the adult brain. Additional studies should now be carried out to determine the specific role played by this protein in the seasonal plasticity of the songbird brain. [less ▲]

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See detailIsolation of Bovine Follicular Dendritic Cells Allows the Demonstration of a Particular Cellular Prion Protein
Thielen, Caroline ULg; Mélot, France ULg; Jolois, Olivier ULg et al

in Cell & Tissue Research (2001), 306(1), 49-55

As interaction of cellular prion protein (PrPc) and the infectious agent (PrPres) appears to be a crucial pathogenic step promoted by homology, variation in PrPc isoforms on bovine immune cells may ... [more ▼]

As interaction of cellular prion protein (PrPc) and the infectious agent (PrPres) appears to be a crucial pathogenic step promoted by homology, variation in PrPc isoforms on bovine immune cells may explain the absence of infectivity in most bovine lymph organs. In this study, we examined PrPc expression in bovine lymph organs (tonsils and lymph nodes) and on isolated follicular dendritic cells (FDCs). We used a panel of different monoclonal antibodies (MoAbs) raised against different epitopes of prion protein. Two MoAbs recognise amino acids 79-92 (SAF 34 and SAF 32 Mo-Abs); the 6H4 antibody reacts with a specific peptide comprising the 144-152 amino acids, and the 12F10 MoAb recognises the sequence 142-160. After immunolabelling of frozen sections of lymph organs with 6H4 or 12F10 MoAbs, we detected cellular prion protein in germinal centres. However, using the SAF 34 or SAF 32 antibodies, PrPc was revealed outside the lymphoid tissues. No PrPc was observed in the germinal centres. Therefore, we adapted the method of FDC isolation, making it suitable for the study of PrPc expression on their surface. Using electron microscopy, the presence of PrPc on the surface of FDCs was demonstrated only with 6H4 MoAb. These results suggest that bovine follicular dendritic cells express a particular form of prion protein. Either the N-terminal part of PrPc is cleaved or the accessibility of the specific epitope (79-92) of SAF 34 MoAb is abolished by interaction with other molecules. This particular isoform of PrPc on bovine FDCs might be related to the apparent absence of infectivity in lymph organs in cattle affected by bovine spongiform encephalopathy. [less ▲]

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See detailNeurotransmitters as Early Signals for Central Nervous System Development
Nguyen, Laurent ULg; Rigo, Jean-Michel; Rocher, Véronique et al

in Cell & Tissue Research (2001), 305(2), 187-202

During brain ontogenesis, the temporal and spatial generation of the different types of neuronal and glial cells from precursors occurs as a sequence of successive progenitor stages whose proliferation ... [more ▼]

During brain ontogenesis, the temporal and spatial generation of the different types of neuronal and glial cells from precursors occurs as a sequence of successive progenitor stages whose proliferation, survival and cell-fate choice are controlled by environmental and cellular regulatory molecules. Neurotransmitters belong to the chemical microenvironment of neural cells, even at the earliest stages of brain development. It is now established that specific neurotransmitter receptors are present on progenitor cells of the developing central nervous system and could play, during neural development, a role that has remained unsuspected until recently. The present review focuses on the occurrence of neurotransmitters and their corresponding ligand-gated ion channel receptors in immature cells, including neural stem cells of specific embryonic and neonatal brain regions. We summarize in vitro and in vivo data arguing that neurotransmitters could regulate morphogenetic events such as proliferation, growth, migration, differentiation and survival of neural precursor cells. The understanding of neurotransmitter function during early neural maturation could lead to the development of pharmacological tools aimed at improving adult brain repair strategies. [less ▲]

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See detailThe Distribution of Tyrosine Hydroxylase in the Canary Brain: Demonstration of a Specific and Sexually Dimorphic Catecholaminergic Innervation of the Telencephalic Song Control Nulcei
Appeltants, D.; Ball, G. F.; Balthazart, Jacques ULg

in Cell & Tissue Research (2001), 304(2), 237-59

Singing and the processing of auditory information related to song can be affected by experimental manipulations of catecholamine activity in the brain of zebra finches. We investigated, by ... [more ▼]

Singing and the processing of auditory information related to song can be affected by experimental manipulations of catecholamine activity in the brain of zebra finches. We investigated, by immunocytochemistry in the brain of male and female canaries, the distribution of tyrosine hydroxylase (TH), the rate-limiting step in the synthesis of catecholamines. Fibers immunoreactive for TH (TH-ir) were particularly abundant in the lobus parolfactorius, the paleostriatum primitivum, and the nucleus septalis lateralis. A high density of TH-ir basket-like structures was observed in the caudomedial neostriatum, an area involved in song perception and recognition. In most males, a high density of TH-ir fibers outlined the telencephalic song control nuclei including the high vocal center, the nucleus robustus archistriatalis, the nucleus interfascialis, the lateral and medial parts of the magnocellular nucleus of the anterior neostriatum, and area X of the lobus parolfactorius. The higher density of fibers immunoreactive for TH in these nuclei, compared with the surrounding telencephalon, supports the notion that the morphological evolution of the song control nuclei was accompanied by a neurochemical specialization. This specific innervation of the song control regions was, in general, not found in females. The specific presence of high densities of TH-ir fibers in the song system of male canaries and the sex difference of this innervation provide anatomical evidence in support of the claim that dopamine and/or norepinephrine play important roles in the modulation of song learning and production. [less ▲]

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See detailFollicular dendritic cells in vitro modulate the expression of Fas and Bcl-2 on germinal center B cells.
Tsunoda, R.; Heinen, Ernst ULg; Sugai, N.

in Cell & Tissue Research (2000), 299(3), 395-402

Germinal center (GC) B cells are highly susceptible to apoptosis. The cellular mechanism regulating this sensitivity, however, has not yet been fully delineated. To investigate whether follicular ... [more ▼]

Germinal center (GC) B cells are highly susceptible to apoptosis. The cellular mechanism regulating this sensitivity, however, has not yet been fully delineated. To investigate whether follicular dendritic cells (FDC) are capable of regulating the susceptibility to apoptosis of GC B cells, we constructed a GC model in vitro: emperipolesis of tonsillar B cells by FDC. We then analyzed the expressions of apoptosis-related proteins (Bcl-2 and Fas) on the cells by three-color flow cytometry. B cells nonentrapped by FDC decreased rapidly in number owing to early apoptosis in vitro, whereas entrapped B cells were rescued for at least 18 h and showed peculiar regulation of Fas and Bcl-2. GC founder cells (CD38+, IgD+; GCFC) and GC B cells (CD38+, IgD-) showed approximately a twofold increased expression of Fas; in contrast, mantle zone B cells (CD38-, IgD+) and memory B cells (CD38-, IgD-) showed no changes. Bcl-2 expression in mantle zone and memory B cells was reduced by approximately one-half; however, GCFC and GC B cells continued to express little Bcl-2 and this did not change. Our findings strongly suggest that FDC play a part in the modulation of the susceptibility to apoptosis on B cells within GC. [less ▲]

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See detailHuman follicular dendritic cells in vitro and follicular dendritic-cell-like cells.
Tsunoda, R.; Bosseloir, A.; Onozaki, K. et al

in Cell & Tissue Research (1997), 288(2), 381-9

Human follicular dendritic cell (FDC)-like cells (FLC) have been utilized for the in vitro analysis of germinal center reactions. However, there is no consensus whether FLC represent FDC in vitro. The ... [more ▼]

Human follicular dendritic cell (FDC)-like cells (FLC) have been utilized for the in vitro analysis of germinal center reactions. However, there is no consensus whether FLC represent FDC in vitro. The purpose of the present study has therefore been to determine distinguishing features of FDC and FLC in vitro. The expression of CD40, CD54, CD49d, cytokine (gamma-IFN and IL-4)-dependent MHC-class II, and CD106 was observed to be specific for the determination of FDC in long-term culture. The cytokine-dependent emperipolesis of germinal center B cells was establised as another discriminating property for FDC in vitro. In 2 out of 72 long-term cultures of FDC, we encountered dividing cells among the non-dividing population of FDC. The dividing cells expressed accessory molecules similar to those of FDC but showed emperipolesis only for the initial few days of their growth. FDC did not enhance the CD40-dependent proliferation of germinal center B cells; in contrast, FLC augumented it. Both types of cells produced a significant amount of cytokine-dependent IL-6. Further studies are needed to determine whether FLC originate from FDC in vitro. [less ▲]

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See detailAromatase-Immunoreactive Cells Are Present in Mouse Brain Areas That Are Known to Express High Levels of Aromatase Activity
Foidart, Agnès ULg; Harada, N.; Balthazart, Jacques ULg

in Cell & Tissue Research (1995), 280(3), 561-74

The transformation of testosterone into estradiol in the brain plays a key role in several behavioral and physiological processes, but it has been so far impossible to localize precisely the cells of the ... [more ▼]

The transformation of testosterone into estradiol in the brain plays a key role in several behavioral and physiological processes, but it has been so far impossible to localize precisely the cells of the mammalian brain containing the relevant enzyme, viz., aromatase. We have recently established an immunohistochemical technique that allows the visualization of aromatase-immunoreactive cells in the quail brain. In this species, a marked increase in the optical density of aromatase-immunoreactive cells is observed in subjects that have been treated with the aromatase inhibitor, R76713 or racemic Vorozole. This increased immunoreactivity, associated with a total blockade of aromatase activity, has been used as a tool in the present study in which the distribution of aromatase-immunoreactive material has been reassessed in the brain of mice pretreated with R76713. As expected, the aromatase inhibitor increases the density of the immunoreactive signal in mice. Strongly immunoreactive cells are found in the lateral septal region, the bed nucleus of the stria terminalis, the central amygdala, and the dorso-lateral hypothalamus. A less dense signal is also present in the medial preoptic area, the nucleus accumbens, several hypothalamic nuclei (e.g., paraventricular and ventromedial nuclei), all divisions of the amygdala, and several regions of the cortex, especially the cortex piriformis. These data demonstrate that, contrary to previous claims, aromatase-immunoreactive cells are present in all brain regions that have been shown previously to contain high aromatase activity. [less ▲]

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See detailAfferent and Efferent Connections of the Sexually Dimorphic Medial Preoptic Nucleus of the Male Quail Revealed by in Vitro Transport of Dii
Balthazart, Jacques ULg; Dupiereux, V.; Aste, N. et al

in Cell & Tissue Research (1994), 276(3), 455-75

The medial preoptic nucleus of the Japanese quail is a testosterone-sensitive structure that is involved in the control of male copulatory behavior. The full understanding of the role played by this ... [more ▼]

The medial preoptic nucleus of the Japanese quail is a testosterone-sensitive structure that is involved in the control of male copulatory behavior. The full understanding of the role played by this nucleus in the control of reproduction requires the identification of its afferent and efferent connections. In order to identify neural circuits involved in the control of the medial preoptic nucleus, we used the lipophilic fluorescent tracer DiI implanted in aldheyde-fixed tissue. Different strategies of brain dissection and different implantation sites were used to establish and confirm afferent and efferent connections of the nucleus. Anterograde projections reached the tuberal hypothalamus, the area ventralis of Tsai, and the substantia grisea centralis. Dense networks of fluorescent fibers were also seen in several hypothalamic nuclei, such as the anterior medialis hypothalami, the paraventricularis magnocellularis, and the ventromedialis hypothalami. A major projection in the dorsal direction was also observed from the medial preoptic nucleus toward the nucleus septalis lateralis and medialis. Afferents to the nucleus were seen from all these regions. Implantation of DiI into the substantia grisea centralis also revealed massive bidirectional connections with a large number of more caudal mesencephalic and pontine structures. The substantia grisea centralis therefore appears to be an important center connecting anterior levels of the brain to brain-stem nuclei that may be involved in the control of male copulatory behavior. [less ▲]

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See detailSex Difference in the Neurotensin-Immunoreactive Cell Populations of the Preoptic Area in Quail (Coturnix Japonica)
Absil, Philippe ULg; Balthazart, Jacques ULg

in Cell & Tissue Research (1994), 276(1), 99-116

The distribution of neurotensin-immunoreactive cells and fibers was analyzed by immunocytochemistry in the forebrain of male and female Japanese quail (Coturnix japonica) by using an antibody directed ... [more ▼]

The distribution of neurotensin-immunoreactive cells and fibers was analyzed by immunocytochemistry in the forebrain of male and female Japanese quail (Coturnix japonica) by using an antibody directed against the C-terminal part of the molecule. [less ▲]

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See detailUltrastructural distribution of DNA within the nucleolus of various animal cell lines or tissues revealed by terminal deoxynucleotidyl transferase.
Thiry, Marc ULg; Ploton, D.; Menager, M. et al

in Cell & Tissue Research (1993), 271(1), 33-45

We have used the highly sensitive in situ terminal deoxynucleotidyl transferase method, applied to ultrathin sections, to investigate the location of DNA within nucleoli of various animal cells. In all ... [more ▼]

We have used the highly sensitive in situ terminal deoxynucleotidyl transferase method, applied to ultrathin sections, to investigate the location of DNA within nucleoli of various animal cells. In all the nucleoli studied, intense labelling is revealed over the peri- and intranucleolar condensed chromatin. Gold particles are also consistently found over the fibrillar centres, especially at their periphery, namely in the border area between the fibrillar centres and the dense fibrillar component, whereas the dense fibrillar component itself seems to be free of label in nucleoli in which these two compartments can be distinguished. We conclude that, in transcriptionally active nucleoli of this type, DNA is a characteristic constituent of the fibrillar centres, distinguishing them functionally from the dense fibrillar component. Some nucleoli exhibit neither fibrillar centres nor a dense fibrillar component, but have a single, albeit heterogeneous accumulation of fibrillar material; gold particles are consistently seen over some parts of this fibrillar compartment. This suggests that certain parts of the fibrillar material are functionally similar to the fibrillar centres of those nucleoli that possess them. [less ▲]

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See detailDistribution of Aromatase-Immunoreactive Cells in the Mouse Forebrain
Balthazart, Jacques ULg; Foidart, Agnès ULg; Surlemont, C. et al

in Cell & Tissue Research (1991), 263(1), 71-9

The distribution of aromatase-immunoreactive cells was studied by immunocytochemistry in the mouse forebrain using a purified polyclonal antibody raised against human placental aromatase. Labeled ... [more ▼]

The distribution of aromatase-immunoreactive cells was studied by immunocytochemistry in the mouse forebrain using a purified polyclonal antibody raised against human placental aromatase. Labeled perikarya were found in the dorso-lateral parts of the medial and tuberal hypothalamus. Positive cells filled an area extending between the subincertal nucleus in the dorsal part, the ventromedial hypothalamic nucleus in the ventral part, and the internal capsule and the magnocellular nucleus of the lateral hypothalamus in the lateral part. The same distribution was seen in the two strains of mice that were studied (Jackson and Swiss), and the number of immunoreactive perikarya did not seem to be affected by castration or testosterone treatment. No immunoreactivity could be detected in the medial regions of the preoptic area and hypothalamus; these were expected to contain the enzyme based on assays of aromatase activity performed in rats and on indirect autoradiographic evidence in mice. Our data raise questions concerning the distribution of aromatase in the brain and the mode of action of the centrally produced estrogens. [less ▲]

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See detailAn Autoradiographic Study of Alpha 1-Adrenergic Receptors in the Brain of the Japanese Quail (Coturnix Coturnix Japonica)
Balthazart, Jacques ULg; Ball, G. F.; McEwen, B. S.

in Cell & Tissue Research (1989), 258(3), 563-8

The neuroanatomical distribution of alpha 1-adrenergic receptors was studied in Japanese quail by quantitative in vitro autoradiography using the specific antagonist [3H]prazosin as the ligand. The ... [more ▼]

The neuroanatomical distribution of alpha 1-adrenergic receptors was studied in Japanese quail by quantitative in vitro autoradiography using the specific antagonist [3H]prazosin as the ligand. The presence of saturable (Bmax less than 200 fmol/mg protein) high affinity (Kd less than 0.12 nM) binding sites was detected by saturation analysis. High concentrations of [3H]prazosin binding sites were detected in the archistriatum/pars ventralis, the hippocampus, the cortex piriformis, the area corticoidea dorsolateralis, the dorsal thalamus, and the nucleus praetectalis. Lower concentrations were seen in the intercollicular nucleus, the lateral septum, and the posterior and tuberal hypothalamus. Very little binding was seen in the preoptic and anterior hypothalamic areas. The relatively high number of binding sites identified in the telencephalic structures agrees well with previous mammalian studies. This is in contrast with the pattern in the anterior hypothalamus where, in mammals, a number of nuclei have been reported to contain a high receptor density. [less ▲]

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See detailA Dorsomedial Subdivision within the Nucleus Intercollicularis Identified in the Japanese Quail (Coturnix Coturnix Japonica) by Means of Alpha 2-Adrenergic Receptor Autoradiography and Estrogen Receptor Immunohistochemistry
Ball, G. F.; Foidart, Agnès ULg; Balthazart, Jacques ULg

in Cell & Tissue Research (1989), 257(1), 123-8

The nucleus intercollicularis is an important site in the control of vocalization in birds. In oscines, a subregion of the nucleus intercollicularis called the dorso-medial intercollicular nucleus appears ... [more ▼]

The nucleus intercollicularis is an important site in the control of vocalization in birds. In oscines, a subregion of the nucleus intercollicularis called the dorso-medial intercollicular nucleus appears to play a key role in this process because it receives the majority of the projections from the nucleus robustus archistriatalis and sends most of the projections to the motor nucleus of the hypoglossal nerve. In this paper, we present neurochemical studies of the nucleus intercollicularis in the Japanese quail which suggest the presence of heterogeneity within this structure. One rostral band contains high densities of cholinergic muscarinic receptors identified by quantitative autoradiography using tritiated N-methylscopolamine as the ligand. A caudal dorso-medial region is specifically labeled by estrogen receptors identified using immunocytochemistry and by alpha 2-adrenergic receptors which were quantified by autoradiography using tritiated para-amino-clonidine. This latter subregion is possibly equivalent to the dorso-medial intercollicular nucleus of oscines. Additional track-tracing studies should be performed to confirm this homology. The coexistence of estrogen and alpha 2-adrenergic receptors within the same structure suggests important functional connections between steroid action and catecholaminergic systems in the brain. [less ▲]

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