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See detailHISTOLOGICAL RESPONSES OF THE SEA ANEMONE A. PALLIDA TO BLEACHING INDUCING STRESSES
Fransolet, David ULg

Doctoral thesis (2014)

Tropical Coral reefs are among the richest and most important ecosystem on Earth. This success would not be possible without the symbiosis established between corals and unicellular algae of the genus ... [more ▼]

Tropical Coral reefs are among the richest and most important ecosystem on Earth. This success would not be possible without the symbiosis established between corals and unicellular algae of the genus Symbiodinium that provide them with photosynthesis-derived carbon. Unfortunately, with the climatic upheaval that we witness today, the long-term survival of coral reefs could be in jeopardy. Massive loss of symbiotic algae, a phenomenon known as coral bleaching, becomes indeed more and more frequent throughout the globe and already urged scientists to study its mechanisms for more than a decade. Their research highlighted the central role of reactive oxygen species in the collapse of symbiosis. They also established that the expulsion of Symbiodinium from its host is mainly operated through the death of the host cell. The ensuing events, although determining the eventual survival of the energetically compromised coral, are however much less detailed. In this work, we decided to investigate these “post-bleaching” events and focused our efforts on the evaluation of cell proliferation and mucocyte number, for the role they may respectively play in regenerative processes and heterotrophic feeding. For this purpose, we worked with the sea anemone model A. pallida in which we analyzed the incorporation of a thymidine analogue (EdU). After preliminary experiments assessing the general repartition and the circadian variations of cellular proliferation in healthy specimens, we conducted a series of bleaching experiments using a variety of stresses. Every treatment, namely cold and darkness, heat and light or exposition to a photosynthesis inhibitor, drastically reduced the Symbiodinium density. This reduction was always accompanied by important histological modifications. In every case, we highlighted an increase in cellular proliferation in both the ectodermis and the gastrodermis as well as an increase in ectodermal mucocyte density. These values returned then to normal as algae that survived the stress progressively repopulated anemones. Further experiments showed that, following bleaching, a small fraction of the newly produced ectodermal cells migrate to the gastrodermis. Along with new gastrodermal cells, they most probably operate a regeneration of the wounded tissue, differentiating into host cells in order to harbor new algae. Another experiment also indicated that a small but significant part of ectodermal newly produced cells might differentiate into mucocytes, therefore explaining their increased density in bleached individuals. We hypothesize that the higher amount of mucus produced, in addition to providing protection against various aggravating stresses, would be a way to efficiently increase the feeding capacity of the bleached cnidarians. This heterotrophic shift would therefore allow a sufficient energy income until full restoration of the symbiosis. This work emphasizes the need to focus more attention on the post-bleaching period, a critical time in which some modifications might be decisive for coral and coral reef survival. [less ▲]

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See detailHistological structure and functions of synovium.
Bassleer, R.; Lhoest-Gauthier, M. P.; Renard, A. M. et al

in Proceedings of the international symposium on articular synovium (1982)

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See detailHistological study of equine interphalangeal joints
Toppets, Vinciane ULg; Pastoret, V.; Antoine, Nadine ULg et al

Poster (2005, July)

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See detailHistological study of immature interspecific embryo abortion between Phaseolus vulgaris L. and P. polyanthus Greenm.
Toussaint, André ULg; Geerts, P.; Mergeai, Guy ULg et al

in Annual Report of the Bean Improvment Cooperative (2003), 46

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See detailHistological study of the horse stifle menisci in relation with ultrasonographic aspect: preliminary study
De Busscher, Virginie; Schreder, Anelaure; Busoni, Valeria ULg et al

in Italian Journal of Anatomy and Embryology (2006), 111

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See detailHistological study of the sex-change in the skunk clownfish Amphiprion akallopisos
Casadevall, Margarida; Delgado, E.; Colleye, Orphal ULg et al

in Open Fish Science Journal (2009), 2

Sex change in the protandrous fish Amphiprion akallopisos Bleeker, 1853 (F.Pomacentridae) has been analysed. Experiments consisted of placing males together after being separated from their mates, and ... [more ▼]

Sex change in the protandrous fish Amphiprion akallopisos Bleeker, 1853 (F.Pomacentridae) has been analysed. Experiments consisted of placing males together after being separated from their mates, and observe changes in gonad histology at different periods, in order to identify signs of the sex change process. The presence of a first invagination on the male gonad wall, and the observation of the first cortical alveoli oocytes as an indication of the beginning of the vitellogenesis process, was the first symptom of the sex change, which has been detected after 18 days in one of the males. Period needed for the sex changing process was size independent. The process by which wall invagination is converted into ovarian lumen in the future mature ovary is also described. [less ▲]

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See detailHistologie générale des animaux domestiques
Antoine, Nadine ULg

Learning material (2009)

Detailed reference viewed: 42 (5 ULg)
See detailHistologie spéciale des animaux domestiques (tome I et II)
Antoine, Nadine ULg

Learning material (2009)

Detailed reference viewed: 37 (1 ULg)
See detailHistology and physiology of skin aging
Quatresooz, Pascale ULg

Conference (2004)

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See detailHistology and ultrastructure of the elastic spring apparatus in Acanthodoras cataphractus (Siluriformes: Doradidae)
Fabri, Grégory; Thiry, Marc ULg; Parmentier, Eric

Poster (2008)

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See detailHistology and ultrastructure of the elastic spring apparatus in Synodontis eupterus
Fabri, Grégory; Montchowui, E; Vandewalle, Pierre ULg et al

Poster (2008)

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See detailHistology of the vaginal wall in women with pelvic organ prolapse: a literature review.
DE LANDSHEERE, Laurent ULg; Munaut, Carine ULg; Richelle, Betty ULg et al

in International Urogynecology Journal (2013), 24(12), 2011-20

INTRODUCTION AND HYPOTHESIS: The pathophysiology of pelvic organ prolapse (POP) is incompletely understood. The purpose of this study is to describe the current knowledge about histology of the vaginal ... [more ▼]

INTRODUCTION AND HYPOTHESIS: The pathophysiology of pelvic organ prolapse (POP) is incompletely understood. The purpose of this study is to describe the current knowledge about histology of the vaginal wall and its possible involvement in the pathogenesis of pelvic organ prolapse. METHODS: Eligible studies were selected through a MEDLINE search covering January 1986 to December 2012. The research was limited to English-language publications. RESULTS: Investigations of changes in the vaginal tissue that occur in women with genital prolapse are currently still limited and produced contrary results. The heterogeneity of the patients and the control groups in terms of age, parity and hormonal status, of the localization of biopsies and the histological methods as well as the lack of validation of the quantification procedures do not allow clear and definitive conclusions to be drawn. CONCLUSIONS: This review shows that current knowledge of the histological changes observed in women with POP are inconclusive and relatively limited. More studies are needed in this specific field to better understand the mechanisms that lead to POP. [less ▲]

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See detailHistology of two rice bodies isolated from the stifle of an adult draught horse stallion.
Schneider, Nicole ULg; Heimann, Marianne; Lejeune, Jean-Philippe ULg et al

in Journal of Veterinary Science (Suwon-si, Korea) (2006), 7(1), 83-5

In the human and equine species, different kinds of free floating intra-articular particles are related to certain disorders. Osteochondral fragments formed during osteochondrosis dissecans are the most ... [more ▼]

In the human and equine species, different kinds of free floating intra-articular particles are related to certain disorders. Osteochondral fragments formed during osteochondrosis dissecans are the most common finding in the equine species, whereas in humans rice bodies due to rheumatoid arthritis are more frequent. Herein we report a third type of floating body inside the stifle of an adult draught horse stallion, in macroscopic appearance similar to articular rice bodies known in humans. As revealed by histologic examination, the two particles consist of polypoid degenerated structures derived from synovial villi. Their formation was probably induced by ischemia. [less ▲]

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See detailHistometric assessment of psoriatic plaques treated by vitamin D3 derivatives.
Uhoda, Isabelle; Quatresooz, Pascale ULg; Hermanns-Lê, Trinh ULg et al

in Dermatology : International Journal for Clinical & Investigative Dermatology (2003), 206(4), 366-9

BACKGROUND: Psoriasis is an immunogenetic disorder. Factor XIIIa+ dermal dendrocytes (DD) are part of the pathobiological changes in the plaque type of the disease. OBJECTIVE: The present study aimed at ... [more ▼]

BACKGROUND: Psoriasis is an immunogenetic disorder. Factor XIIIa+ dermal dendrocytes (DD) are part of the pathobiological changes in the plaque type of the disease. OBJECTIVE: The present study aimed at comparing the effect of 3 vitamin D(3) derivatives on the epidermis, microvasculature and DD in psoriasis. METHOD: Twenty men suffering from chronic plaques of psoriasis on the trunk were enrolled in this study. They applied twice a day for 3 weeks calcipotriol, tacalcitol and calcitriol, each to one plaque. Another similar lesion received petrolatum as a placebo treatment. Skin biopsies were taken at entry and at completion of the 3-week treatment phase. Immunohistochemistry was performed using the lectin of Ulex europaeus and an antibody to factor XIIIa. Computerized image analysis served to measure the stratum Malpighii area, the microvasculature area and the DD numerical density in the papillary dermis. RESULTS: At entry in the study, the 4 test sites were indistinguishable with regard to the stratum Malpighii area, the papillary microvasculature area and the papillary DD density. The 3 histometric parameters appeared correlated with each other. At completion of the 3-week treatment phase, the 3 vitamin D derivatives had decreased the size of the stratum Malpighii. In addition, calcitriol had also reduced the DD density in the papillary dermis. No other significant changes were yielded. CONCLUSION: As assessed by histometry, the psoriatic epidermis responded to a short treatment using the 3 vitamin D derivatives. The better result compared to the control site was achieved by calcitriol. DD appeared to be most controlled by the same drug. The microvasculature did not appear to be decreased at the 3-week time point in treatment. [less ▲]

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See detailHistomycologie de la biodiversité des onychomycoses
PIERARD, Gérald ULg; ARRESE ESTRADA, Jorge ULg; QUATRESOOZ, Pascale ULg

in Baran, R.; PIERARD, Gérald (Eds.) Onychomycoses (2004)

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See detailHistomycologie unguéale
Arrese Estrada, Jorge ULg; Quatresooz, Pascale ULg; Franchimont, Claudine ULg et al

in Annales de Dermatologie et de Vénéréologie (2003), 130

The diversity of onychomycoses is large when the disease is scrutinized using traditional, fluorescence or confocal microscopy. Histomycology is a non-invasive assessment performed on nail clippings. The ... [more ▼]

The diversity of onychomycoses is large when the disease is scrutinized using traditional, fluorescence or confocal microscopy. Histomycology is a non-invasive assessment performed on nail clippings. The location of and the density in fungal cells is variable. In some instances, these aspects remain clinically unsuspected. In vivo confocal microscopy can bring the same information. Computerized image analysis of histological sections is the most performant means for quantifying the fungal load. Immunohistochemistry brings information about the identity of the fungus or the association of different fungi present in the nail plate. Mixed infections may be unifocal or located at different levels in the nail apparatus. The viability of fungi as assessed by vital stains can be assessed under the microscope and quantified by flow cytometry. The different facets of nail histomycology are complementary and shed some light on aspects sometimes unsuspected of onychomycoses. [less ▲]

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See detailHistone deacetylase 4 is required for TGF beta 1-induced myofibroblastic differentiation
Glenisson, Wendy; Castronovo, Vincenzo ULg; Waltregny, David ULg

in Biochimica et Biophysica Acta-Molecular Cell Research (2007), 1773(10), 1572-1582

Transforming Growth Factor beta 1 (TGF beta 1) is a crucial cytokine triggering myofibroblastic (MF) differentiation, a process involved in tissue healing as well as in pathologic conditions such as ... [more ▼]

Transforming Growth Factor beta 1 (TGF beta 1) is a crucial cytokine triggering myofibroblastic (MF) differentiation, a process involved in tissue healing as well as in pathologic conditions such as fibrosis and cancer. Together with cell shape modifications, TGF beta 1-mediated differentiation of fibroblasts into myofibroblasts is characteristically associated with the neo-expression of smooth muscle alpha-actin (alpha-SMA), a cytoskeletal protein that enhances their contractile activity. Several cellular differentiation programs have been linked to epigenetic regulation of gene expression, including gene methylation and historic acetylation. Herein, we sought to investigate the role of histone deacetylases (HDAC) in TGF beta 1-induced MY differentiation. We found that TSA, a global inhibitor of class I and class II HDACs, prevented alpha-SMA transcript and protein expression and morphological changes mediated by TGF beta 1 in cultured human skin fibroblasts. In order to identify the HDAC(s) participating in MF differentiation, the impact of specific HDAC silencing (HDAC1 through HDAC8) using RNA interference was investigated in fibroblasts exposed to TGF beta 1. Among the eight HDACs tested, silencing of HDAC4, HDAC6, and HDAC8 expression impaired TGF beta 1-induced alpha-SMA expression. HDAC4 silencing most efficiently abrogated alpha-SMA expression and also prevented TGF beta 1-mediated morphological changes. Forced down-regulation of HDAC4 stimulated the expression of 5'-TG-3'-Interacting Factor (TGIF) and TGIF2 homeoproteins, two known endogenous repressors of the TGF beta signaling pathway, but not of the inhibitory Smad7. Collectively, these data suggest that HDAC4 is an essential epigenetic regulator of MF differentiation and unveil HDAC4 as a potential target for treating MF-related disorders. (C) 2007 Published by Elsevier B.V. [less ▲]

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See detailHistone deacetylase 5 is a regulator of S phase progression
Peixoto, Paul ULg; Pirotte, Sophie ULg; Matheus, Nicolas ULg et al

Poster (2011, February 05)

Detailed reference viewed: 15 (5 ULg)