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Histological Similarities (histological + similarity)
Selected AbstractsCyclo-Oxygenase 2 Function Is Essential for Bone Fracture Healing,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2002Ann Marie Simon Abstract Despite the molecular and histological similarities between fetal bone development and fracture healing, inflammation is an early phase of fracture healing that does not occur during development. Cyclo-oxygenase 2 (COX-2) is induced at inflammation sites and produces proinflammatory prostaglandins. To determine if COX-2 functions in fracture healing, rats were treated with COX-2-selective nonsteroidal anti-inflammatory drugs (NSAIDs) to stop COX-2-dependent prostaglandin production. Radiographic, histological, and mechanical testing determined that fracture healing failed in rats treated with COX-2-selective NSAIDs (celecoxib and rofecoxib). Normal fracture healing also failed in mice homozygous for a null mutation in the COX-2 gene. This shows that COX-2 activity is necessary for normal fracture healing and confirms that the effects of COX-2-selective NSAIDs on fracture healing is caused by inhibition of COX-2 activity and not from a drug side effect. Histological observations suggest that COX-2 is required for normal endochondral ossification during fracture healing. Because mice lacking Cox2 form normal skeletons, our observations indicate that fetal bone development and fracture healing are different and that COX-2 function is specifically essential for fracture healing. [source] Mixed Nasal Mucus as a Model for Sinus Mucin Gene Expression StudiesTHE LARYNGOSCOPE, Issue 2 2002FRCS, Mahmoud S. Ali MSc Abstract Objective/Hypothesis It is necessary to obtain sinus mucus from the paranasal sinus cavities to study mucin gene expression occurring in the sinuses during chronic sinusitis. This requires an invasive procedure to access the sinus cavity. There are embryological as well as histological similarities between nasal and sinus epithelia; therefore, we postulated that the mucin expression in the secreted nasal and sinus mucins might be similar. Nasal mucus, which can be obtained easily, could then replace sinus mucus in these studies. Study Design Sinus and nasal mucus from six patients with chronic sinusitis were analyzed in this study. Methods High-molecular-weight glycoproteins (mucins) were isolated and purified by sequential density gradient centrifugation in caesium chloride (CsCl). Enzyme-linked immunosorbent assay was performed to identify the antigenic identity of these mucins. Results The MUC2, MUC5AC, and MUC5B mucin genes were all expressed in the nasal and sinus mucus secretions. Antigenic studies showed an inverse relationship between MUC2 and MUC5AC expression in nasal and sinus mucus secretions. The MUC5B gene was the major mucin gene expressed in sinus mucus but not in nasal mucus. Expression of MUC2 was significantly higher in sinus mucus. Expression of MUC5AC was different between nasal and sinus mucus. Conclusions Individual mucin expression in sinus and nasal mucus was markedly different. From this preliminary study, we conclude that nasal mucus is not a suitable substitute for sinus mucus in sinus mucin gene studies and that different pathological processes are taking place in nasal and sinus tissue in chronic sinusitis. [source] Medallion-like dermal dendrocyte hamartoma: the main diagnostic pitfall is congenital atrophic dermatofibrosarcomaBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2009M. Marque Summary Medallion-like dermal dendrocyte hamartoma is a newly described and rare clinical and pathological entity. This congenital, round, erythematous and atrophic lesion in the thoracic area is histologically characterized by a CD34+ dermal and hypodermal spindle-cell infiltration. We describe the clinical, histopathological, cytological and molecular features of three cases of dermal dendrocyte hamartoma. In all the cases, atrophic congenital dermatofibrosarcoma protuberans (DFSP) was the first histological diagnosis. In one case, wide surgery had been performed on the basis of the clinical and histological presentation. The histological pattern was similar in all the cases: epidermal atrophy and a spindle to ovoid cell proliferation in the dermis and in the subcutaneous fat. Immunochemical staining for CD34 and factor XIIIa was positive. Cytogenetic and molecular studies were performed; no chromosomal abnormality nor translocation t(17;22)(q22;q13) was observed. Fluorescence in situ hybridization analysis did not reveal the DFSP fusion gene COL1A1-PDGFB. We observed that the main diagnostic pitfall of medallion-like dermal dendrocyte hamartoma is atrophic congenital DFSP due to clinical and histological similarities. We emphasize that molecular studies to eliminate the t(17;22)(q22;q13) translocation of DFSP may provide determinant elements for diagnosis in order to avoid unnecessary mutilating surgery. [source] Role of Wnt signaling in the biology of the periodontiumDEVELOPMENTAL DYNAMICS, Issue 1 2010Scott M. Rooker Abstract Continuously erupting teeth have associated with them a continuously regenerating periodontal ligament, but the factors that control this amazing regenerative potential are unknown. We used genetic strategies to show that the periodontal ligament arises from the cranial neural crest. Despite their histological similarity, the periodontal ligament of continuously erupting incisor teeth differs dramatically from the periodontal ligament of molar teeth. The most notable difference was in the distribution of Wnt responsive cells in the incisor periodontal ligament, which coincided with regions of periodontal ligament cell proliferation. We discuss these findings in the context of dental tissue regeneration. Developmental Dynamics 239:140,147, 2010. © 2009 Wiley-Liss, Inc. [source] Grover's disease, despite histological similarity to Darier's disease, does not share an abnormality in the ATP2A2 geneBRITISH JOURNAL OF DERMATOLOGY, Issue 3 2000J. Powell No abstract is available for this article. [source] | ||||||||||