ISSN:0904-2512    

DOI:10.1111/j.1600-0714.1981.tb01241.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe current knowledge of the structure, expression and functions of fibronectin is reviewed.Fibronectin is a high molecular weight glycoprotein present in the blood, connective tissue and at cell surfaces. It is synthesized by many types of differentiated cells and is believed to be involved in the attachment of cells to the surrounding extracellular matrix. Fibronectin has affinity to the other main components of extracellular matrix, collagen and glycosaminoglycans. It also interacts with cell surfaces as shown by the fact that fibronectincollagen complexes, or fibronectin alone when insolubilized on a surface such as plastic, enhances the attachment of various types of cells to such surfaces.It seems that fibronectin, through its binding to collagen and to the cell surface, forms a bridge between the cell and its surrounding matrix. Circulating fibronectin may participate in the formation of extracellular matrix in tissues. It may also function as a nonspecific opsonin designed to facilitate the uptake of tissue debris by phagocytic cells.Studies aimed at elucidating the significance of fibronectin in physiological phenomena and in disease have only just begun. The abundance of fibronectin in basement membrane structures and the developmental changes observed in its expression lead one to believe that the attachment (or lack of it) of cells to fibronectin plays a significant role in morphogenetic events or in normal development. Malignantly transformed cells tend to lack cell‐associated fibronectin. The significance of the lack of surface fibronectin in transformed cells is a matter of some controversy, but if fibronectin is indeed the main mechanism that anchors cells to the extracellular matrix, disturbances of this mechanism could play an important role in malignancy and many other disease

ISSN:0904-2512    

DOI:10.1111/j.1600-0714.1981.tb01242.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

We present the second case of plasmacytoid myoepithelioma of the palate, which was studied by light and electron microscopy. Apart from plasmacytoid cells, some spindle‐shaped cells were also observed. Both types of neoplastic cells had myoepithelial features, showing abundant 50–80 A thick filaments in the cytoplasm, and exhibited desmosomal junctions. A few light cells with less abundant filaments and better equipped with other organelles were observed.Our findings show that there is no clear‐cut distinction between the so‐called plasmacytoid myoepithelioma and the spindle and stellate myoepithelioma. We suggest that the ultrastructural appearance of these tumors together with the usual histological criteria for malignancy may be used to evaluate their pr

ISSN:0904-2512    

DOI:10.1111/j.1600-0714.1981.tb01243.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractSix weanling male Sprague Dawley rats were fed a diet containing 0.4 ppm Zn and seven were fed an identical diet except for 40 ppm Zn. After 4 weeks, specimens of buccal mucosa in the region facing the molar teeth were removed. Paraffin sections, cut at 6 μ, were stained with toluidine blue, and tracings made of five sections per animal, spaced no less than 60 μm apart. Counts of mast cells over a measured length of section were made in a superficial zone of the lamina propria of 50 μm width and a deeper zone of 250 μ width.The average number of mast cells per mm in the subepithelial zone of the experimental animals was 15.4, the range 9.2–33.1. The control average was 4.0; the range was 2.9–5.3. No increase was found in the deeper zone.The epithelium was parakeratotic and its thickness was increased two‐fold. In the peripheral portion of the section, cellular and keratin layers were evenly increased in thickness, but in the central portion a disproportionate, nearly four‐fold increase occurred in the keratin layer and a lesser increase in the cel

ISSN:0904-2512    

DOI:10.1111/j.1600-0714.1981.tb01244.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe crystallographic features of various histological sites found in enamel carious lesions were studied by means of X‐ray microbeam diffraction. The most interesting finding was that the crystallinity of apatite crystals in the intact surface layer covering the demineralized lesions was higher than that of the crystals in the subsurface lesions or unaffected areas. Acid‐dissolution experiments using synthetic hydroxyapatite pellets showed that a well mineralized layer was produced on the pellet surface under the condition that no Ca and PO4ions were added to the initial acidic solution. Furthermore, X‐ray diffraction analysis revealed that half‐line breadth values of 004, 222, and 310 reflections of apatite pellets decreased, and their integrated peak intensities increased with dissolution time. These findings are in agreement with the results obtained in the study of enamel carious lesions, leading to the conclusion that the intact surface layer is formed by deposition of the mineral ions from dissolving subsurface lesions, and that this process is accompanied by the improvement in crystallinity of apatite crystals, possibly due to growth of the c

ISSN:0904-2512    

DOI:10.1111/j.1600-0714.1981.tb01245.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractYoung adult nonhuman primates were initially fed an ascorbic‐acid free diet and, subsequently, a diet with a suboptimal level of the vitamin. Following approximately 12 weeks of this dietary regime, five of seven experimental animals developed scorbutic gingivitis. 2 to 3 weeks prior to this stage, the permeability of the gingival sulcular epithelium to3Hinulin, but not to14C‐butyric acid or14C‐urea, had increased significantly (+86%, P<0.01) in the experimental group as compared to ad libitum or pair‐fed controls. This defect in the intercellular permeability barrier of the sulcular epithelium could have contributed to the pathogenesis of scorbutic gin

ISSN:0904-2512    

DOI:10.1111/j.1600-0714.1981.tb01246.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractLengths of capillaries and epithelial dimensions were measured on tracings of sections of buccal mucosa stained for alkaline phosphatase from rats on a zinc‐deficient diet.The zinc‐deficient animals showed the following increases over controls: length of capillaries, ×2.67; thickness of cell layer, ×1.47; thickness of keratin layer, ×2.82; basal layer length: surface length ratio, ×1.41. Lengthening of the basal layer and the capillaries showed high positive correlations with thickening of the cell layer. Lengthening of the capillaries exceeded the lengthening of the basal layer and the thickening of the epithelium but fell short of the increased anabolic performance of the epithelium as quantitated in previous investi

ISSN:0904-2512    

DOI:10.1111/j.1600-0714.1981.tb01247.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractWe report the first instance of transplacental induction of an ameloblastoma using a nitrosourea compound. This model may be of use in the study of odontogenic tumors.

ISSN:0904-2512    

DOI:10.1111/j.1600-0714.1981.tb01248.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Books reviewed in this article:Animal Tissue Techniques, 4th edn., Gretchen L. HumasonInternational Endodontic Journal.

ISSN:0904-2512    

DOI:10.1111/j.1600-0714.1981.tb01249.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

ISSN:0904-2512    

DOI:10.1111/j.1600-0714.1981.tb01250.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY