Studies on fibronectin in the skin

Fibronectin is an important constituent of normal human skin, mediating cell/cell and cell/fibre interactions. In affected skin in discoid and systemic LE, changes in the distribution of fibronectin in the dermo-epidermal junction and in the papillary dermis are observed with homogenization and degenerative changes, IF negative gaps and slit formation in the dermo-epidermal region, together with IF positive globular bodies and transport of fibronectin into the epidermis. Unaffected skin in LE demonstrates the pattern of fibronectin as found in normal human skin.     

Studies on fibronectin in the skin

Summary Affected and unaffected skin from patients with vulgar psoriasis and normal skin from a control group were investigated for the presence of fibronectin with an indirect immunofluorescence technique. In the control group, fibronectin is missing in the epidermis, but is found in the basement membrane zone of the dermo-epidermal junction area, in the papillary and the reticular dermis, and in the vascular and neural systems of the skin. The same distribution is also found in unaffected psoriatic skin, whereas in affected skin a change in the distribution of fibronectin is found in the dermis and in the basement membranes, together with the presence of fibronectin in the epidermis, mainly in the cornified layers.     

Studies on fibronectin in the skin. VII. Production in cell cultures from normal human skin

In the present study, cell cultures of fibroblasts from normal skin have been investigated regarding the production of fibronectin. The development of multimeric insoluble fibronectin is demonstrated as small dots at the cell surface, developing into a branched meshwork of fibrous structures in parallel arrays. Soluble dimeric fibronectin is also found in the culture medium.     

Studies on fibronectin in the skin. III. Indirect immunofluorescence studies in lichen planus.

Fibronectin is a glycoprotein which is responsible for a varity of functions in the human organism, such as mediation of contact between cells and between cells and fibres, opsonic qualities, interaction in the stabilization of fibrin, etc. Fibronectin is an important constituent of the ground substance having a special affinity to collagen. In indirect immunofluorescence studies its presence has been abundantly demonstrated in normal human skin, in collagen-rich structures such as the basement membranes, the papillary and reticular dermis, and in the vascular and neural structures, demonstrable by its characteristic staining patterns. Fibronectin is not found in the epidermis. In lichen planus, the distribution in unaffected skin is identical with that in normal skin, whereas in affected skin, changes in the pattern of fibronectin are found. The basement membrane zone becomes broader and hazy, later undergoing disintegration and destruction, concomitant with swelling and homogenization of the reticular distribution of fibronectin in the papillary dermis. Globular structures containing fibronectin are found in the basement membrane area, together with an intensified immunofluorescence in the vascular system. Fibronectin has certain adhesional properties and changes in the distribution of this glycoprotein may result in loss of tissue stability. The pathophysiological significance of the changes of fibronectin in lichen planus is, however, difficult to evaluate at present.     

Distribution of fibronectin in the skin of patients with scleroderma

The distribution of fibronectin (FN), a major glycoproteic component of extra-cellular matrix, has been studies by an indirect immunofluorescence technique in the skin of 50 normal controls and 19 sclerodermic patients. In the normal skin, FN was present mainly in the papillary dermis, as thin strips and less abundant in reticular dermis, bound to collagen bundles. In scleroderma skins, FN was increased in the deep dermis of extensive and evolutive lesions (11 cases). In an other hand, the distribution of FN was not modified in stabilized lesions (8 cases). We conclude that the detection of FN in the scleroderma skin is an useful marker of the activity of the systemic sclerosis process and we discuss the possible role of FN as a primary matrix for organization of the collagenous connective tissue during the sclerosing process.     

Production of fibronectin by epithelium in a skin equivalent

Although human keratinocytes in vitro have been shown to produce fibronectin, whether keratinocytes can contribute fibronectin to the dermal-epidermal junction or wound matrix is unknown. In order to approach this problem experimentally, we used the "skin equivalent" model composed of a native collagen gel populated with cultured fibroblasts and covered by cultured keratinocytes. By using bovine fibroblasts to populate the gel, fetal bovine serum in the culture medium, and human keratinocytes to form the epithelium, we were able to be certain that any human fibronectin produced in the culture was synthesized by the keratinocytes. A monoclonal antibody to fibronectin was found to recognize human but not bovine fibronectin. When the skin equivalent was stained by indirect immunofluorescence with antifibronectin, fibronectin was visible as an intensely staining band at the dermal-epidermal junction. In sections in which the dermis and epidermis had separated, the staining was usually limited to the dermal aspect of the skin equivalent. The results indicate that epithelium can contribute fibronectin to the dermal-epidermal junction and suggest that dermal staining in skin sections may originate from the epidermis. Since the developing skin equivalent has a rapidly growing epithelium and simulates a healing wound, contribution of fibronectin by the epithelium, in addition to that possibly contributed by serum and fibroblasts, may be of importance in wound healing.     

皮肤鳞癌中纤维连接蛋白表达对癌生物学行为的影响

观察纤维连接蛋白在皮肤鳞癌中的表现形式,探讨其与ＳＳＣ生物学行为和癌间质巨噬细胞,淋巴细胞反应的关系。用ＦＮ、ＰＣＮＡ、ＣＤ６８地５０例ＳＳＣ作免疫组化染色,检测在癌中的表达。结果显示ＦＮ在ＳＳＣ中表现为３种形式,细胞ＦＮ、基膜ＦＮ与间质ＦＮ,细胞ＦＮ与基膜ＦＮ常同时消失,与ＳＳＣ的生长、分化、增殖,转移密切相关,而且其减少程度与局部ＭφＬｃ浸润量的减少有潜在的平行关系。本文结果说明ＳＳＣ中细胞Ｆ     

Studies on the effect of salicylic acid on normal skin

This investigation was prompted by our ignorance of the way in which salicyhc acid aids desquamation. Salicylic acid in aqueous cream or white soft paraffin and in concentrations of 2–12%, was applied to normal skin of twenty-three subjects while the vehicle alone was apphed to the contralateral sites. Biopsies and skin surface biopsies were taken from the test and control sites after 1 week. Histological examination showed that there was less horny layer on the test specimens but that there were no qualitative or quantitative differences in the structure of the viable epidermis. Portions of the biopsies were incubated in the presence of tritiated precursor compounds and subsequent autoradiographic examination showed no difference in the incorporation of thymidine, cytidinc or histidine between test and control preparations. Scanning electron microscopy of skin surface biopsies showed some changes in all specimens—presumably due to hydration—but also showed strking differences between test and control sites and were especially marked with higher concentrations of salicylic acid. It is suggested that salicylic acid causes desquamation by dissolution of intercellular cement material.     

Studies on age-related diseases in cultured skin fibroblasts.

In order to trace the origins of age-dependent diseases to the cellular level, we studied cultured human fibroblasts from subjects with 3 discrete inherited disorders and normal controls of various ages. Skin fibroblasts from subjects with progeria and Werner syndrome had a moderate to severe reduction in growth capacity, whereas cells from subjects with diabetes mellitus had a more subtle growth impairment. There was a decreased response of progeric fibroblasts to insulin-like hormones, and in normal cells the response decreased as a function of the passage level and donor age. Tissue factor, a procoagulant, was more abundant in progeric and Werner fibroblasts. An understanding of fibroblast aging in vitro may help us explain various concomitant phenomena of organismic aging such as diabetes mellitus, cell dropout, impaired hormone responsiveness, and increased atherothrombosis.     

皮肤移植物及嵌合体内郎格罕细胞的研究

本文报告以抗Ia单克隆抗体检查表皮内LC的方法,观察了皮肤移植物内及嵌合体内不同基因型LC的结果.结果显示,移植物内原有LC的大部分可被宿主LC所迅速更换,而小部分能持续存在而不被更换,从而提示LC可能存在二个亚群,其一经常移动,另一则较长期(>249天)地固定.结果又显示,输注骨髓细胞或脾、淋巴绪细胞后的嵌合体的表皮内,无例外地可检测到供体基因型的LC;从而提出了一种国内外迄今未使用过的简便准确的检测嵌合体的新方法,建议使用这一方法于动物实验及临床观察.     

Studies on the skin surface dosage of dermatopharmaceutical preparations]

In human volunteers presenting with normal skin an investigation has been carried out to determine the specific skin surface dose, the actual application volume, and the theoretical surface film thickness resulting from thin and thick layer inunction of 4 common corticosteroid topicals. The findings obtained indicate that the skin surface dose provides the most suitable criterion for the terrain saturation behaviour exhibited by different formulation types of semi-solid topical preparations (inunguenda). Various aspects of the surface dosage concept are discussed with regard to the active agents and forms of application of external skin remedies. Predicative clinical determinations of the skin surface doses of topicals relating to special therapeutic and assessment procedures are believed to be a valuable complement to experimental (predictive) determinations of this parameter; some problems involved are pointed out by reference to a clinical trial example. Data on the application dosage of topicals--either by skin surface dose or by volume or layer thickness quantification--have been extracted from the dermatological literature and are reviewed with the aim of furnishing a basis for comparative estimation of our experimental results.     

Studies on fibronectins in the skin. VIII. Influence of corticosteroids on cell cultures from normal human skin

Fibronectins are important glucoproteins of mesenchymal tissue. Fibronectins are also found in the human skin, and tissue cultures demonstrate the production of soluble dimers and insoluble fibrous polymers from dermal fibroblasts. Under the influence of different glucocorticoids, inhibited production of these fibronectins from cultured human skin cells is demonstrated.     

Studies and perspectives of signal transduction in the skin

Tumor-promoting phorbol ester and epidermal growth factor (EGF) exert marked influences on the proliferation and differentiation of keratinocytes. These two agents bring their physiological functions into play via protein kinase C (PKC) activation (and/or down regulation) and protein tyrosine kinase, respectively. In this paper, the present situation in the studies on the signal transduction of keratinocytes centering around these two kinases is discussed. An outline of studies on signal transduction of cells other than keratinocytes in the skin is also given.