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Main Cell Types (main + cell_type)
Selected AbstractsArthroplasty membrane-derived fibroblasts directly induce osteoclast formation and osteolysis in aseptic looseningJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2005A. Sabokbar Abstract Purpose: Both macrophages and fibroblasts are the main cell types found in periprosthetic tissues surrounding failed joint arthroplasties. These fibroblasts are known to express RANKL and to produce TNF,, factors which promote osteoclast formation and bone resorption. In this study we have analysed the role that arthroplasty membrane-derived fibroblasts (AFb) play in inducing the generation of bone resorbing osteoclasts. Methods: Fibroblasts were isolated from periprosthetic tissues and co-cultured with human monocytes in an osteoclast differentiation assay in the presence or absence of M-CSF and inhibitors of RANKL (OPG) and/or TNF,. RANKL expression by AFbs was determined by RT-PCR and the extent of osteoclast differentiation by the expression of TRAP, VNR and evidence of lacunar resorption. Results: In the presence of M-CSF, large numbers of TRAP+ and VNR+ multinucleated cells capable of lacunar resorption, were noted in co-cultures of monocytes and RANKL-expressing AFbs. Cell-cell contact was required for osteoclast formation. The addition of OPG and anti-TNF, alone significantly reduced but did not abolish the extent of osteoclast formation, whereas the addition of both together abolished osteoclast formation and lacunar resorption. Conclusion: Our results indicate that fibroblasts in periprosthetic tissues are capable of inducing the differentiation of normal human peripheral blood mononuclear cells to mature osteoclasts by a mechanism that involves both RANKL and TNF,. Suppression of both RANKL and inflammatory cytokines is likely to be required to control periprosthetic osteolysis. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] EARLY DEVELOPMENT PATTERN OF THE BROWN ALGA ECTOCARPUS SILICULOSUS (ECTOCARPALES, PHAEOPHYCEAE) SPOROPHYTE,JOURNAL OF PHYCOLOGY, Issue 5 2008Aude Le Bail The distant phylogenetic position of brown macroalgae from the other multicellular phyla offers the opportunity to study novel and alternative developmental processes involved in the establishment of multicellularity. At present, however, very little information is available about developmental patterning in this group. Ectocarpus siliculosus (Dillwyn) Lyngb. has uniseriate filaments and displays one of the simplest architectures in the Phaeophyceae. The aim of this study was to decipher the morphogenetic steps that lead to the development of the Ectocarpus sporophyte. We carried out a detailed morphometric study of the events that occurred between gamete germination and the 100-cell stage. This analysis was performed on two ecologically distant isolates to assess plasticity in developmental patterning within this species. Cell sizes were measured in both isolates, allowing the definition of two main cell types based on their shape (round and elongated). On average, the filament is composed of about 40% round cells, which are present in the central region of the filament, but different combinations of the two cell types within filaments were observed and quantified. Young sporophytes grew apically, with elongated cells progressively differentiating into round cells. Secondary filaments emerged preferentially on round cells, primarily from the older central cells. Statistical analyses showed that the pattern of branching was regulated to ensure a stereotyped architecture. This description of the developmental patterning during the growth of the E. siliculosus sporophyte will serve as a base for more detailed studies of development, in this species and in brown algae in general. [source] Short-Term Antiandrogen Flutamide Treatment Causes Structural Alterations in Somatic Cells Associated with Premature Detachment of Spermatids in the Testis of Pubertal and Adult Guinea PigsREPRODUCTION IN DOMESTIC ANIMALS, Issue 3 2010LR Maschio Contents In spite of widespread application of flutamide in the endocrine therapies of young and adult patients, the side effects of this antiandrogen on spermatogenesis and germ-cell morphology remain unclear. This study evaluates the short-term androgen blockage effect induced by the administration of flutamide to the testes of pubertal (30-day old) and adult (65- and 135-day old) guinea pigs, with an emphasis on ultrastructural alterations of main cell types. The testes removed after 10 days of treatment with either a non-steroidal antiandrogen, flutamide (10 mg/kg of body weight) or a pharmacological vehicle alone were processed for histological, quantitative and ultrastructural analysis. In pubertal animals, flutamide androgenic blockage induces spermatogonial differentiation and accelerates testes maturation, causing degeneration and detachment of primary spermatocytes and round spermatids, which are subsequently found in great quantities in the epididymis caput. In post-pubertal and adult guinea pigs, in addition to causing germ-cell degeneration, especially in primary spermatocytes, and leading to the premature detachment of spherical spermatids, the antiandrogen treatment increased the relative volume of Leydig cells. In addition, ultrastructural evaluation indicated that irrespective of age antiandrogen treatment causes an increase in frequency of organelles involved with steroid hormone synthesis in the Leydig cells and a dramatic accumulation of myelin figures in their cytoplasm and, to a larger degree, in Sertoli cells. In conclusion, the transient exposition of the guinea pigs to flutamide, at all postnatal ages causes some degenerative lesions including severe premature detachment of spermatids and accumulation of myelin bodies in Leydig and Sertoli cells, compromising, at least temporarily, the spermatogenesis. [source] Systematic significance of fruit morphology and anatomy in tribes Persicarieae and Polygoneae (Polygonaceae)BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1-2 2000LOUIS P. RONSE DECRAENE FLS Fruits of Polygonaceae have a basically similar construction of indchiscent nuts or achencs. Sections of fruits, coupled with surface patterns were studied with SEM and LM in all genera of the tribes Persicarieae and Polygoneae (Polygonoidcae-Polvgonaceae). The outer layer of the pericarp is usually thickened and its anatomy can be used consistently to delimit genera more than any other character of the fruit. Cells are most often puzzle piece-shaped in surface view, but the shape of the cells may become polygonal with straight anticlinal walls towards the endocarp. The primary sculpture of the cells is highly yariable and has value at the specific level, rarely at the generic level. No strict correlation exists between the external surface patterns and the anatomy. Two main cell types can be recognized in cross- and longitudinal section, correlated with the straight or undulating outline of the anticlinal walls. No distinction can be made between sections Persicaria, Tovara, Echinocaulon, and Cephalophtlon of the genus Persicaria: all share narrow rectangular cells with undulating anticlinal walls. Aconogonon and Bistorta can be delimited by the square to rectangular cells with a narrow dichotomously branching lumen and straight anticlinal walls; both genera are best grouped as a single genus with two sections. A similar arrangement is found occasionally in species of Polygonum s.s. Polygonella. Atraphaxis. Faltopia and Calligonum. Fruit anatomy of Pteropyrum is distinctive. The genus Polygonum s.s. shows a wide range of integrating patterns, ranging from straight to undulating anticlinal walls and cannot be separated from Polygonella. Fagopyrum is aberrant in having a parenchymatic exocarp and a thickened mesocarp: other evidence supports its isolated position. Different fruit anatomical patterns have arisen several times in evolution and have a limited value at tribal level but are useful at generic level. It is suggested that an arrangement with straight anticlinal walls and a broad lumen, eventually with dendritic branching towards the periphery, is ancestral. [source] | ||||||||||