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Tissue Organization (tissue + organization)
Selected AbstractsComparison of acidic fibroblast growth factor on collagen carrier with calcium hydroxide as pulp capping agents in monkeysDENTAL TRAUMATOLOGY, Issue 5 2007Zhimei Li Abstract,,, Acidic fibroblast growth factor (aFGF) has been shown to facilitate wound healing by stimulating fibroblast proliferation and angiogenesis. It has also been reported to possess a powerful anti-apoptotic function This study compared the histological pulp responses to aFGF on collagen carrier and Ca(OH)2 placed on the mechanically exposed dental pulp in monkeys at two observation periods. Thirty-six teeth with pulp exposures were distributed into three groups according to the capping agents used prior to application of the coronal seal: collagen-based matrix carrier (group 1), aFGF on the collagen-based matrix carrier (group 2) and aqueous calcium hydroxide [Ca(OH)2] paste (group 3). Specimens were harvested at 6 and 13 weeks postoperatively and prepared for hematoxylin and eosin, and Gram staining. Histological qualitative evaluation of pulp responses were performed under the light microscope following criteria modified from Cox et al. (17) and Hu et al. (18). Semi-quantitative analysis was also carried out using Kruskal,Wallis and Mann,Whitney U -tests. There was neither negligible inflammatory infiltrates with no bacteria present in the three groups at both timings, nor was there any significant difference in the soft tissue organization among the three groups at or between the 6- and 13-week observation periods. At 6 weeks, the hard tissue barrier produced by Ca(OH)2 group (1.040 ± 0.089) was significantly more superior than aFGF/collagen carrier group (1.930 ± 0.825) (P = 0.030) as well as collagen carrier group (3.142 ± 1.069, P = 0.018). At 13 weeks, both aFGF/collagen carrier group (1.214 ± 0.485) and the collagen carrier group (1.457 ± 0.814) produced significantly better hard tissue barrier (P = 0.040 and P = 0.017, respectively) than earlier timing. However, these two groups did not induce significantly improved hard tissue barrier compared to that produced by aqueous Ca(OH)2 paste which stimulated matrix secretion in a polar tubular dentin-like pattern. [source] Hair biology: an updateINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2002B. A. Bernard Synopsis In the past few years, the hair follicle has started revealing its beauty and mysteries. The existence of a growth and regeneration cycle, together with a unique tissue organization and complex regulatory network, make it a true paradigm of tissue homeostasis and dermal,epithelial crosstalk. In this brief review, I will describe some of the most recent results obtained in this very active research field of hair biology, underlining the diversity of the molecular signals that control hair growth and pigmentation. Résumé Au cours des dernières années, le follicule pileux a commencéà révéler sa beauté et ses mystères. L'existence d'un cycle de croissance et de régénération, d'une organization tissulaire unique et d'un circuit complexe de régulation désigne le follicule pileux comme un paradigme d'homéostasie tissulaire et d'interactions dermo,épithéliales. Dans cette courte revue, je décris quelques uns des résultats récemment obtenus dans ce domaine de recherche très actif, en soulignant l'extrême diversité des signaux moléculaires qui contrôlent la croissance du cheveu et sa pigmentation. [source] Correlations between the Sonic Hedgehog Pathway and basal cell carcinomaINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 11 2007Omar Lupi MD The Hedgehog (HH) family of intercellular signaling proteins has some essential functions in patterning both invertebrate and vertebrate embryos. Identified as an important regulator of segment polarity and tissue organization in flies, the HH pathway can also play a significant role in human development and in cutaneous carcinogenesis. The family received their name because when the D. melanogaster HH protein malfunctions the mutant fly ends up looking like a small prickly ball, similar to a curled up hedgehog. The Sonic hedgehog (SHH) pathway is implicated in the etiology of the most common human cancer, the basal cell carcinoma (BCC). Mutations in the receptor of SHH, the patched gene (PTCH), have been characterized in sporadic BCCs as well as those from patients with the rare genetic syndrome nevoid BCC. Human PTCH is mutated in sporadic as well as hereditary BCCs, and inactivation of this gene is probably a necessary if not sufficient step for tumorigenesis. Delineation of the biochemical pathway in which PTCH functions may lead to rational medical therapy for skin cancer and possibly other tumors. [source] Fell-Muir Lecture: Cartilage 2010 , The Known UnknownsINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 3 2010Timothy E. Hardingham Summary Over the past 40 years there have been giant steps forward in our understanding of cellular and molecular biology that have given us the framework by which to understand tissue organization and tissue function on a range of scales. However, although the progress has been great, the more we have discovered, the more we are aware of what we don't yet know. In this article, I would like to flag up some issues of cartilage biology, function and pathology where we still have significant ignorance. As scientists we all provide contributions to add to the greater understanding of science and progress is on a broad front, but gaps are left where particular difficulty is encountered and in life sciences it is no different. Progress is fast where new knowledge and techniques pave the way, but where study is complex and relevant techniques poorly developed the gaps are left behind. In cartilage research and matrix biology, the gaps can particularly be seen at interfaces between disciplines and where technology development has lagged behind and in the particular challenges of understanding how molecular properties can explain tissue macro properties. [source] Inflammation-associated remodelling and fibrosis in the lung , a process and an end pointINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 2 2007William A.H. Wallace Summary Fibrosis by common usage in the pathological and clinical literature is the end result of a healing process and synonymous with scarring. We would argue that its use to describe a dynamic series of events which may be reversible is unhelpful and that the term ,lung remodelling' is a better description for this process as it reflects changes in tissue organization that may or may not progress to ,fibrosis' as a final fixed point. Resolution, through reversal of active lung remodelling, by therapeutic intervention is possible providing the alveolar architecture remains intact. If the lung architecture is lost then healing by permanent fibrosis with loss of organ function is inevitable. [source] Anatomics: the intersection of anatomy and bioinformaticsJOURNAL OF ANATOMY, Issue 1 2005Jonathan B. L. Bard Abstract Computational resources are now using the tissue names of the major model organisms so that tissue-associated data can be archived in and retrieved from databases on the basis of developing and adult anatomy. For this to be done, the set of tissues in that organism (its anatome) has to be organized in a way that is computer-comprehensible. Indeed, such formalization is a necessary part of what is becoming known as systems biology, in which explanations of high-level biological phenomena are not only sought in terms of lower-level events, but are articulated within a computational framework. Lists of tissue names alone, however, turn out to be inadequate for this formalization because tissue organization is essentially hierarchical and thus cannot easily be put into tables, the natural format of relational databases. The solution now adopted is to organize the anatomy of each organism as a hierarchy of tissue names and linking relationships (e.g. the tibia is PART OF the leg, the tibia IS-A bone) within what are known as ontologies. In these, a unique ID is assigned to each tissue and this can be used within, for example, gene-expression databases to link data to tissue organization, and also used to query other data sources (interoperability), while inferences about the anatomy can be made within the ontology on the basis of the relationships. There are now about 15 such anatomical ontologies, many of which are linked to organism databases; these ontologies are now publicly available at the Open Biological Ontologies website (http://obo.sourceforge.net) from where they can be freely downloaded and viewed using standard tools. This review considers how anatomy is formalized within ontologies, together with the problems that have had to be solved for this to be done. It is suggested that the appropriate term for the analysis, computer formulation and use of the anatome is anatomics. [source] Detailed Visualization of the Functional Regions of the Rat Pituitary Gland by High-Resolution T2-Weighted MRIANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 3 2010E. Theunissen With 5 figures and 1 table Summary This high-resolution MRI study focuses on the visualization of the detailed morphology of the rat's pituitary gland by means of post-mortem as well as in vivo MRI at 9.4 T. Determination of the local T1- and T2-relaxation decay times allows to explain the regional image intensities which reflects the degree of tissue organization at the molecular level. Detailed characterization of the molecular level of the pituitary gland, as provided by the relaxation decay times, can offer a rigid platform with respect to functional or pathological explorations. It is demonstrated that T1-weighted imaging, as is routinely used in the clinic, can differentiate between the posterior and anterior lobe but not between the posterior and intermediate lobe. T2-weighted images, however, clearly show the three distinct lobes of the rat pituitary gland without the use of contrast agents, i.e. the posterior, the intermediate and the anterior lobe. Histological analysis of the rat's pituitary gland confirms the morphological structures seen on the MR images. Although the intermediate lobe is less defined in humans and can neither be differentiated by T1-weighted MRI, its clinical visualization might be possible in T2-weighted images. [source] Adherens junctions: new insight into assembly, modulation and functionBIOESSAYS, Issue 8 2002Ulrich Tepass Adherens junctions play pivotal roles in cell and tissue organization and patterning by mediating cell adhesion and cell signaling. These junctions consist of large multiprotein complexes that join the actin cytoskeleton to the plasma membrane to form adhesive contacts between cells or between cells and extracellular matrix. The best-known adherens junction is the zonula adherens (ZA) that forms a belt surrounding the apical pole of epithelial cells. Recent studies in Drosophila have further illuminated the structure of adherens junctions. Scaffolding proteins encoded by the stardust gene are novel components of the Crumbs complex, which plays a critical role in ZA assembly.1,3 The small GTPase Rap1 controls the symmetric re-assembly of the ZA after cell division.4 Finally, the asymmetric distribution of adherens junction material regulates spindle orientation during asymmetric cell division in the sensory organ lineage.5 BioEssays 24:690,695, 2002. © 2002 Wiley Periodicals, Inc. [source] Hydrogel-Perfluorocarbon Composite Scaffold Promotes Oxygen Transport to Immobilized CellsBIOTECHNOLOGY PROGRESS, Issue 2 2008Kyuongsik Chin Cell encapsulation provides cells a three-dimensional structure to mimic physiological conditions and improve cell signaling, proliferation, and tissue organization as compared to monolayer culture. Encapsulation devices often encounter poor mass transport, especially for oxygen, where critical dissolved levels must be met to ensure both cell survival and functionality. To enhance oxygen transport, we utilized perfluorocarbon (PFC) oxygen vectors, specifically perfluorooctyl bromide (PFOB) immobilized in an alginate matrix. Metabolic activity of HepG2 liver cells encapsulated in 1% alginate/10% PFOB composite system was 47,104% higher than alginate systems lacking PFOB. A cubic model was developed to understand the oxygen transport mechanism in the alginate/PFOB composite system. The theoretical flux enhancement in alginate systems containing 10% PFOB was 18% higher than in alginate-only systems. Oxygen uptake rates (OURs) of HepG2 cells were enhanced with 10% PFOB addition under both 20% and 5% O2 boundary conditions, by 8% and 15%, respectively. Model predictions were qualitatively and quantitatively verified with direct experimental OUR measurements using both a perfusion reactor and oxygen sensing plate, demonstrating a greater OUR enhancement under physiological O2 boundary conditions (i.e., 5% O2). Inclusion of PFCs in an encapsulation matrix is a useful strategy for overcoming oxygen limitations and ensuring cell viability and functionality both for large devices (>1 mm) and over extended time periods. Although our results specifically indicate positive enhancements in metabolic activity using the model HepG2 liver system encapsulated in alginate, PFCs could be useful for improving/stabilizing oxygen supply in a wide range of cell types and hydrogels. 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