The lipid composition of porcine epidermis and oral epithelium

The permeability barrier of mammalian skin has been analysed in terms of its lipid composition whereas that of the oral mucosa is uncharacterized. As there are differences in permeability between different regions of the oral mucosa, and between the oral mucosa and skin, there may be corresponding differences in the nature of the barrier layer. Lipids were identified by thin-layer chromatography after solvent extraction of separated epithelium; their localization was determined in histological sections using standard histochemical stains. Keratinized oral epithelium and epidermis showed a similar pattern of lipid distribution, the majority of neutral lipids being ceramides, localized around the cells of the stratum corneum. The non-keratinized epithelium contained few neutral lipids but polar lipids, particularly cholesterol sulphate and glucosylceramides, were clearly evident. Histochemical staining suggested that these were localized in intercellular regions throughout the epithelium. The differences in the types and distribution of lipids accord well with known permeability differences, which show that keratinized oral epithelium and epidermis have a similar impermeability to water and that non-keratinized regions have greater permeability.     

Age-associated changes in Langerhans cells of murine oral epithelium and epidermis

Oral mucosa and skin of older individuals are immunologically less responsive to a range of allergens, but it is not known whether this is due to changes in the number of Langerhans cells or to impaired cell function. EDTA-separated epithelial sheets from the cheek and palate mucosa, and from ear and footpad skin of three-month-old and 24-month-old C57BL/6NNia mice were stained for ATPase, beta-glucuronidase activity and Ia^b-surface antigen to demonstrate Langerhans cells. The general distribution of such cells was unchanged with age, but those in epithelia from the old mice were more varied in shape, with irregular cell bodies and more elongated dendritic processes. The numerical density of Langerhans cells in old mice was reduced by 30–59 per cent compared with that in young mice.     

Penetration pathways different compounds through epidermis and oral epithelia

The permeability of skin and oral mucosa to various compounds has been measured but the actual pathways substances take in traversing the epithelia have not been identified. In this study, radiolabelled cholesterol, ethanol or water were placed on the surface of porcine skin, keratinized gingiva, or nonkeratinized floor of mouth mucosa, and incubated at 37°C for 2 h. The tissue was then snap-frozen, and sectioned in a cryostat, picked up on precoated slides and exposed at -20°C for 40 days for light microscopic autoradiography. Some tissues were freeze-dried and directly embedded in low viscosity resin and prepared for electron microscopic autoradiography Examination of autoradiographs revealed silver grains over, or adjacent to, intercellular spaces. Counts of the grains over the extra- and intracellular compartments were made in random light and electron microscope fields. For all compounds and tissue regions, there were significantly more (p<0.05) grains over the intercellular spaces than over the cells. The results indicate that the intercellular compartment is the predominant route for compounds moving across the superficial barrier layer of epidermis and oral epithelia. The nature of the intercellular material is, thus, a primary determinant of epithelial permeability.     

Penetration pathways of different compounds through epidermis and oral epithelia

The permeability of skin and oral mucosa to various compounds has been measured but the actual pathways substances take in traversing the epithelia have not been identified. In this study, radiolabelled cholesterol, ethanol or water were placed on the surface of porcine skin, keratinized gingiva, or nonkeratinized floor of mouth mucosa, and incubated at 37 degrees C for 2 h. The tissue was then snap-frozen, and sectioned in a cryostat, picked up on precoated slides and exposed at -20 degrees C for 40 days for light microscopic autoradiography. Some tissues were freeze-dried and directly embedded in low viscosity resin and prepared for electron microscopic autoradiography. Examination of autoradiographs revealed silver grains over, or adjacent to, intercellular spaces. Counts of the grains over the extra- and intracellular compartments were made in random light and electron microscope fields. For all compounds and tissue regions, there were significantly more (p less than 0.05) grains over the intercellular spaces than over the cells. The results indicate that the intercellular compartment is the predominant route for compounds moving across the superficial barrier layer of epidermis and oral epithelia. The nature of the intercellular material is, thus, a primary determinant of epithelial permeability.     

口腔异常增生上皮PCNA及细胞核面积分层计数的临床意义

目的观察口腔异常增生上皮不同层次及鳞癌组织中增殖细胞核抗原(PCNA)及上皮细胞核面积的变化.探讨二者与异常增生等级的关系及临床意义.方法采用免疫组化S-P法、形态测量学方法对正常口腔黏膜上皮(NOR)和实验组口腔黏膜上皮[包括轻度异常增生(LD)、中度异常增生(MD)、重度异常增生(SD)及高分化鳞癌(简称鳞癌SCC)]的PCNA指数(PI)及细胞核面积进行检测并分层计数.结果实验组上皮基底层均较高表达PCNA,与NOR比较差异显著(P<0.01),而实验组组间无显著性差异(P>0.05);随着病变程度的加重,棘层PI逐渐增加,除MD与SD组,SD与SCC组外,其余各组组间均有显著性差异(P<0.05);表层(颗粒层和角质层)SD组的PI增加,与MD组比较差异显著(P<0.05);全层PI在 MD、SD及SCC组间无显著性差异(P>0.05).上皮细胞的核面积随着病变程度加重有逐渐增大的趋势.基底层核面积除SD与SCC组外,其余各组间差别显著(P<0.05);棘层核面积病变组与正常组间,LD与SD、SCC组间差异显著(P<0.05).相关分析显示核面积与PI相关显著(P<0.01);PI及核面积与异常增生等级均呈正相关(P<0.01).结论PI与核面积从不同角度反映了细胞的增殖水平,基底层以上PCNA指数及基底层核面积能更好反映上皮异常增生程度,是临床判断异常增生等级的重要辅助指标.     

Activity of glucose-6-phosphate dehydrogenase and acid phosphatase in nonkeratinized and keratinized oral epithelium and epidermis in the rabbit

There are very few reports in the literature on biochemical and histochemical comparative studies of enzyme activity in nonkeratinized and keratinized regions of oral epithelium in the same individuals of a species. Reported studies have dealt for the most part only with keratinized epithelium, and they suggest an important role for glucose-6-phosphate dehydrogenase and acid phosphatase in the process of keratinization. This is based on increasing activity of the two enzymes towards the surface of keratinized epithelium and decreasing activity in nonkeratinized. To eliminate the possibilitv that the differences observed are individual or species differences, non- keratinized and keratinized oral epithelia from the same animals were assayed. The ratio of activity in keratinized epithelium to that in nonkeratinized reachcd 13:l for acid phosphatase and 2:1 for glucose-6-PO₄ dehydrogenase. In nonkeratinized, activity of both enzymes decreased steadily towards the surface. In keratinized, acid phosphatase increased dramatically towards the surface; glucose-6-PO₄ dehydrogenase increased at first and then decreased. These findings offer evidence that the biochemical activities represented by the two enzymes have an important role in keratinization.     

Gangliosides in human palatal oral epithelium.

Gangliosides were analysed with biochemical methods. The total concentration of gangliosides, expressed as N-acetylneuraminic acid, was 75 nmoles per gram fresh weight. Ten separate gangliosides were revealed. The pattern was dominated by mono- and disialo-gangliosides, together amounting to 96 mole-per cent, and of which G_d3 was the greatest (24 mole-per cent). Gangliosides of plasma membranes have surface receptor functions, e.g. to entero- and staphylococcal toxins and myxovirus. From the relatively high content of gangliosides, oral epithelial gangliosides may contribute to the barrier function of the oral mucosa.     

人牙龈结合上皮、口腔龈上皮及沟内上皮中细胞角蛋白的表达

目的 检测人牙龈上皮的细胞角蛋白(CK)谱，探讨结合上皮(JE)与口腔龈上皮(OE)、沟内上皮(SE)的不同。方法 5例人磨牙及前磨牙牙龈颊舌向石蜡切片，采用免疫组化SP法行CK5／6、7、8／18、10／13、16、17、19、20染色。结果 CK7、17在3种上皮中均无表达；CK5／6、20在3种上皮的基底上层(尤其是近表层)为弱阳性及阳性表达，基底层无表达；CK10／13、16在JE全层均有表达，在OE和SE仅限于基底上层，其中CK10／13为强阳性，CKl6为弱阳性及阳性；CK19在JE全层强阳性，在OE和SE仅限于基底层，JE和SE分界明显；CK8／18与CK19相似，只是表达较弱，近基底层的基底上层也有少量表达。结论JE是一种不同于OE和SE的特殊低分化上皮，CK19可作为JE的特征性标记物区别于OE和SE，CK10／13、16可用于体外培养的上述3种细胞的鉴别。     

LETS protein in normal and pathological human oral epithelium.

The distribution of LETS protein in human oral mucosa was studied by indirect immunofluorescence. Normal epithelium showed surface staining. Intracellular staining occurred in epithelial cell cytoplasm in lichen planus and pemphigoid. Surface staining was absent in discoid lupus erythematosus. In pemphigus, intercellular staining was seen near areas of acantholysis.     

Surface characteristics of cells from different layers of keratinized and non-keratinized oral epithelia

Portions of clinically healthy non-keratinized and keratinized oral epithelia were removed from adult vervet monkeys (Cercopithecus aethiops). The epithelium was separated from the underlying lamina propria by trypsin digestion, following which the epithelial cells were separated from the various epithelial layers. These were examined with the light and scanning electron microscope. Cells from non-keratinized epithelia have surface microplications while those from keratinized epithelia show microvilli and pits. Two distinct types of cell are therefore present. It is suggested that the different surface appearances are related to different types of mechanical adhesion between the cells.     

Immuno-histochemistry of keratin in normal and diseased human oral epithelium.

Immuno-reactivity of human oral epithelial proteins was investigated by indirect immuno-fluorescence microscopy in normal and pathological conditions. Reactivity to antiserum was seen throughout the epithelium in normal oral mucosa and in lichen planus. Reactivity of epithelial cells was variable in erythema multiforme, pemphigoid and pemphigus.     

Mitotic activity in the oral epithelium of the albino rat.

In groups of Wistar rats 3 and 12 months of age, colchicine and radioautography were used to assess mitotic activity in oral epitheliums. Apparent mitotic activity in the epitheliums of the cheek, hard palate, and central, intermediate, and lateral zones of the soft palate depended on the method used and the age of the rat.     

Plasminogen activators in normal and malignant oral epithelium in vivo and in vitro.

Urokinase-type (uPA) and tissue-type (tPA) plasminogen activators were identified by fibrinolytic autography in the sulcus epithelium of human gingival mucosa but not in the orthokeratinized gingival epithelium. Fibrinolytic activity was present only over blood vessels in frozen sections of oral squamous cell carcinomas, the malignant epithelial cells showing no plasminogen activator activity. Plasminogen activators could not be demonstrated in either the sulcus or gingival epithelium by immunofluorescence, but both uPA and tPA were found in occasional squamous carcinoma cells. Fibrinolytic activity of culture fluids from epithelial explants grown in vitro from human gingival mucosa showed marked variation, but activity was much higher in the culture supernatants than in the cell lysates. Fibrinolytic activity of culture fluids from epithelial explants of squamous cell carcinomas was low both in supernatants and lysates. Zymogram overlays of sodium dodecyl sulphate-polyacrylamide electrophoretic gels from culture supernatants showed that the low fibrinolytic activity of culture supernatants of oral squamous cell carcinomas was due to the associated presence of plasminogen activator inhibitors. The fibrinolytic activity in the zymogram was due predominantly to uPA but some lysis was due also to tPA.     

细胞角蛋白14在牙齿软组织萌出通道中的组织学定位

目的牙齿萌出时,源于成釉器的缩余釉上皮与口腔上皮细胞融合为上皮团形成牙齿的软组织萌出通道,本研究对细胞角蛋白14在这一过程中的表达进行组织学定位,从而探讨其可能作用。方法不同发育期SPF级BALB/c小鼠9只。循环内固定后分别双侧下颌骨10%EDTA脱钙30d,常规脱水包埋,近远中向5μm连续切片,行苏木精-伊红和免疫组化染色。PV免疫组化两步法检测细胞角蛋白14和细胞增殖核抗原在各组织的表达。结果牙齿萌出过程中口腔上皮对细胞角蛋白14呈现时空特异性表达,非牙齿萌出部位的口腔上皮仅基底层阳性表达细胞角蛋白14,而萌出牙齿冠方的口腔上皮阳性表达则较广泛;缩余釉上皮在牙齿萌出过程中始终阳性表达细胞角蛋白14,而且伴随缩余釉上皮和口腔上皮融合的发生,缩余釉上皮的外层细胞和口腔上皮的基底层和基底上层细胞呈现细胞角蛋白14强阳性表达。结论细胞角蛋白14与牙齿萌出软组织通道的形成密切相关,可作为缩余釉上皮相关研究的上皮性标记物。     

Comparative ultrastructure of oral epithelium in fish and amphibia

The palatal epithelium and adjacent lamina propria of two species of fish and two species of amphibia were examined with the electron microscope. Corydoras posessed an orthogonal orientation of collagen fibres in the lamina propria. An unusual cell was described in the lamina profria of Bufo which contained large rhomboidal masses in the cytoplasm, possibly representing stored material. All four species studied contained abundant tonofilaments in the oral epithelium although they were not grouped to form tonofibrils as one sees in human oral mucosa. All species contained demosomes connecting the epithelial cells, and a basement lamina separating the basal cells from the lamina propria. Individual mucous cells were frequently observed in the epithelium. Dense granules, usually about 0.13 microns in diameter and of unknown composition were present in the palatal epithelium of Amphiuma. Specialized cells containing large amounts of arganualr endoplasmic reticulum oriented into a lattice-work of hollow tubes were visualized in the oral epithelium of Corydoras. The outer-most cells of the Corydoras palatal epithelium appeared to undergo a dehydration and compacting of cytoplasmic components which suggested a primative type of keratinization.