Number Of Collagen Fibrils Research Articles

The differentiation of the dermis in the laboratory mouse.

The purpose of this study was to provide a comprehensive and sequential account of the differentiation of the dermis in one body region in a mammalian species. A histological, histochemical, and ultrastructural study was made of each cellular and matrix component of the dermis of the upper lip of the mouse during prenatal development. On the basis of these observations, the development of the dermis was divided into four phases: I) undifferentiated mesenchyme (12, 13 days), II) cell differentiation (14, 15 days), III) dynamic transition (16 days), and IV) matrix differentiation (beginning at 17 days). The first phase was marked by a decrease in the cell density but no change in the ultrastructure of the undifferentiated mesenchyme cells. The second phase began with the cytodifferentiation of the mesenchyme cells and was characterized by the appearance of new cell types in the dermis (immature fibroblasts, mast cells, myoblasts, and cells of indeterminate type). During phase III the dermis was undergoing rapid change. Fibroblasts became fully differentiated, mast cell density reached a sharp peak, there was a marked increase in the number of collagen fibrils in the dermal matrix and the first collagen fibers were observed, and changes occurred in the pattern of proteoglycan synthesis. Aggregations of vesicles appeared to be extruded from cytoplasmic blebs on the fibroblasts in large quantities at this time. Further differentiation of the dermal intercellular matrix occurred during the fourth phase, which continued after birth, as more collagen was laid down to form the connective tissue stroma.

The submucous layer of the middle ear in chronic otitis media. II. Chronic suppurative otitis media. A histological and ultrastructural study.

In continuation of a previous study on the submucous layer of the middle ear in chronic secretory otitis, the authors describe the same structure in chronic suppurative otitis. The changes proved to be identical with those of chronic secretory otitis, only far more pronounced. As a sign of the suppurative nature of the inflammation, there was marked infiltration of the tissue by neutrophilic leukocytes. Eosinophilic leukocytes were not demonstrated. In the stroma there was an increase in the number of collagen fibrils more marked than in secretory otitis. There were also signs of degenerative changes of the collagen fibrils, in the form of fibrinoid transformation, fibrolysis, and possibly also hyaline transformation. In the present study it was not possible to investigate necrosis, if any, of the bone beneath the submucosa. However, it is a fact that chronic suppurative otitis often involves necrosis of the ossicles. This has previously been explained as a consequence of anoxia caused by the suppurative inflammation, but the proliferation of the capillary network with increased blood flow found in the present study militates against this theory. In a subsequent study it will be endeavoured to elucidate whether such necrosis may be caused, under certain circumstances, by an increased number of histiocytes and neutrophilic leukocytes with a content of lysosomes.

腸管吻合創治癒過程の組織化学的,電子顕微鏡的研究

The healing process of anastomosed jejunum of rats is studied using radioautography and electron microscopy.From three hours to seven days after operation, DNA synthesizing zone increases in the crypt cells around the anastomosed area. This phenomenon is not observed at later stages after operation.Regenerative epithelial cells start to appear from the 2nd post-operative day. They are cubic in shape and their micro-villi are shorter and less numerous than those seen in the matured epithelial cells. In the regenerative epithelial cells, one seldom sees endoplasmic reticulum in contrast to numerous free ribosomes. Parallel to the post-operative days, villous regeneration has begun to form themselves like budding and consequently regenerative cells become more differentiated, resembling the matured villous cells.In stroma around the anastomosed area, the numbers of fibroblasts rapidly increase at the 3rd post-operative day, and one observes extensive development and dilatation of endoplasmic reticula.Small numbers of collagen fibrils are found extracellularly at the 4th post-operative day, and numbers of fibrils and their widths have continued to increase as the time lapses.In malnutrition, DNA synthesizing zone in the crypt cells is on the lesser increase and the proliferation of connective tissue cells is in retard as compared with control animals.Fibroblasts show autolytic degeneration at the 7th post-operative day in the ill-nourished animals.

VITAMIN C--SULFONAMIDE COMPOUNDS IN THE HEALING OF WOUNDS: THE USE OF SULFANILAMIDE ASCORBATE IN THE TREATMENT OF CHRONIC SUPPURATION OF THE WOUND AFTER RADICAL MASTOIDECTOMY

When von Jeney and Toro 1 added ascorbic acid to the nutrient medium of a culture of fibroblasts in vitro and observed a marked increase in the number of collagen fibrils, the basis was laid for an advance in the local treatment of wounds. Since the repair and the tensile strength of wounds in soft tissues are direct functions of the proliferation of fibroblasts and the formation of collagen, it is evident that vitamin C plays an important role in the phenomenon of wound healing. Saitta 2 reported delayed healing of exposed surface wounds in guinea pigs that had been kept on a vitamin C—deficient diet for more than fifteen days. On the other hand, when a vitamin C–containing extract was applied directly to the wound, the time of healing was appreciably diminished, regardless of whether the animals were maintained on a normal or a scorbutic dietary regimen. He determined the rate

Effect of Absolute and Partial Vitamin C Deficiency on Healing of Wounds.

It is now well established that the intercellular substances in general, and the collagen of all fibrous tissue structures in particular require ascorbic acid for their production and maintenance. Aschoff and Koch1 made thorough postmortem studies of World War soldiers who had died of scurvy, and demonstrated constant pathological changes in the supporting tissues of the body. Hojer2 found a general atrophy of the connective tissue in scorbutic guinea pigs, and pointed out for the first time a general deficiency in the formation of collagen. In a series of more recent communications Wolbach345 and his collaborators confirmed the observations of Hojer, and conclusively showed that ascorbic acid is intimately concerned with the synthesis and maintenance of intercellular supporting materials. Jeney and Toro,6 when they added ascorbic acid to the nutrient medium of a culture of fibroblasts in vitro, found a marked increase in the number of collagen fibrils that were produced.Since the repair and tensile stren...