Epidermolysis bullosa herpetiformis (Dowling-Meara type) exhibits ultrastructural derangement of tonofilaments and desmosomes

Ultrastructural and immunohistochemical studies of clinically intact skin obtained from three severe neonatal cases of epidermolysis bullosa herpetiformis (Dowling-Meara type) demonstrated disorders in the assembly of keratin intermediate filaments and desmosomes of the keratinocytes. During mitosis, K5- and K14-positive and K1- and K10-negative tonofilaments were disrupted and formed spherical bodies associated with intracytoplasmic desmosomes by invagination of the desmosomes and the adjacent plasma membrane. During the invagination process, destructive changes in the internalized membrane were noted. These were accompanied by gradual loss of reactivity with a monoclonal antibody ZK31, which detected plasma membrane adjacent to the attachment plaques of desmosomes. However, the reactivity of the attachment plaques of the internalized desmosomes for desmoplakins and desmoglein did not decline during the process of internalization. In the suprabasal layers of the epidermis, filamentous substructures and K1 and K10 appeared at the periphery of the spherical bodies. Simultaneously, the desmosomes that were sparsely located in the lower epidermis, increased in number as cell differentiation progressed. Thus, the keratinocytes attained an almost normal appearance with respect to tonofilaments and desmosomes by the time they reached the upper layer of the epidermis. These findings may be relevant to the mechanism responsible for the clinical appearance of the herpetiform blisters in epidermolysis bullosa herpetiformis, which are also characterized by spontaneous involution during childhood or when exposed to high ambient temperatures.Part of this work was presented at the annual meeting of the Japanese Society for Ultrastructural Cutaneous Biology, 12 May 1990, Tokushima, Japan, at the joint meeting of the Society for Cutaneous Ultrastructure Research and the Japanese Society for Ultrastructural Cutaneous Biology, 23–25 May 1991, Vienna, Austria, and at the sixth Conference on Disorders of Keratinization, 6 July 1991, Tokyo, Japan     

Lamellar cells of sensory receptors and perineural cells of nerve endings of pig skin contain cytokeratins

Summary The lamellar cells of the sensory corpuscles of the pig dermis must be considered to be epithelial cells as they contain cytokeratins. The cytokeratins detected are similar to those found in simple epithelia. Moreover, lamellar cells are embedded in an extracellular matrix reminiscent of the basement membrane of epithelium since it contains laminin and collagen IV. The perineural cells surrounding the nerves of pig dermis present the same features.These results suggest that lamellar cells and perineural cells have the same origin. The nature of the lamellar and perineural cells of the rabbit or human dermis is not as clear since cytokeratins were not detected in those cells. These results, together with recent observations on Merkel cells, may indicate that epithelio-neuronal junctions are a general feature of cutaneous sensory receptors.     

桥粒斑蛋白II在肿瘤组织中的表达

桥粒斑蛋白ＩＩ（ＤＰＩＩ）是一种新的上皮和上皮性肿瘤标记物。我们应用针对石蜡切片的抗ＤＰＩＩ单抗和抗细胞角蛋白（ＣＫ）单抗对２ｌ７例肿瘤作了免疫组织化学ＡＢＣ法染色的研究，结果：在１６３例上皮性肿瘤和双向分化的肿瘤中，１４７例表达ＤＰＩＩ，占９０．７％，９２例表达ＣＫ，占５６．４％。ＣＫ阳性染色全部位于细胞浆内，ＤＰＩＩ阳性染色则同时分布在细胞交界面上和细胞浆中。其他５４例不含桥粒的肿瘤均无ＤＰＩＩ和ＣＫ表达。结果表明，ＤＰＩＩ单抗是有用的含桥粒肿瘤的免疫组化探针。因ＤＰＩＩ不存在于一切含桥粒肿瘤，故在鉴别上皮性肿瘤时，ＤＰＩＩ单抗尚需与其他上皮标记物的抗体合并使用。     

Antidesmosomal monoclonal antibody in the diagnosis of intracranial tumours

Immunocytochemistry has been applied extensively to the diagnosis of intracranial tumours, but meningiomas still present a diagnostic problem. However, desmosomes have been shown by electron microscopy to be present in meningiomas, and this distinguishes them from gliomas. This paper describes a new monoclonal antibody, 11-5F, against desmosomal proteins 1 and 2 (desmoplakins) and assesses its usefulness in the diagnosis of meningiomas and other intracranial tumours. A total of 74 surgically removed intracranial tumours were examined by fluorescent antibody staining with 11-5F on frozen sections. In addition, a panel of antibodies against cytokeratin, vimentin, glial fibrillary acidic protein, and S100 protein was used. 11-5F stained 30/30 meningiomas and 14/14 metastatic carcinomas but 0/30 gliomas, thus distinguishing meningiomas and metastatic carcinomas from gliomas. The distinction between meningiomas and metastatic carcinomas on the basis of intermediate filaments staining was more difficult because neither the anticytokeratin nor the antivimentin antibody was specific for either tumour type. This study emphasizes the value of antidesmosomal antibodies as an important adjunct to the diagnosis of intracranial tumours.     

Desmosomes,corneosomes and desquamation. An ultrastructural study of adult pig epidermis

Summary We recently developed a pig skin model to determine the role of corneosomes (modified desmosomes in the stratum corneum) and extracellular lipids in desquamation. The present study provides control morphometric data on the morphological changes in desmosomes and corneosomes leading to desquamation in adult pig epidermis in vivo. The extracellular space within desmosomes gradually widened from the basal to the granular layer, and decreased slightly in the stratum corneum. Mid-dense line broadening, and increased electron density of the distal light layers, coincided with membrane-coating granule extrusion in the outer granular layer. Corneocyte attachment correlated with corneosome distribution. Compactum packing was relatively tight and corneosomes were numerous. Cohesion was mainly peripheral in the disjunctum, and corneosomes were restricted to corneocyte edges. Adhesion had a tongue-and-groove appearance with corneosomes riveting corneocyte peripheries into a lipped groove on adjoining cells. Cells shed by peeling radially towards the lipped groove, and corneosomes decreased from lower to upper disjunctum. Corneosome breakdown commenced with an electron lucent band forming between the plug and lipid envelope. The plug was then unzipped from the lipid envelope and degraded. Corneosomes did not form squamosomes.     

Mode of action of glycolic acid on human stratum corneum: ultrastructural and functional evaluation of the epidermal barrier

Alpha-hydroxy acids (AHA) such as glycolic acid have recently been used extensively in cosmetic and dermatological formulas. In low concentration (2– 5%) glycolic acid is believed to facilitate progressive weakening of cohesion of the intercellular material of the stratum corneum (SC), resulting in uniform exfoliation of its outermost layers (the stratum disjunctum). Since thinning of the SC as well as changes of intercellular lipids could theoretically compromise the barrier functions of the skin, we investigated the mode of AHA action on the SC to determine whether enhanced desquamation compromises the barrier structures of the SC and changes transepidermal water loss (TEWL) values. Electron microscopy of the epidermis biopsied from the volar forearm of human volunteers after 3 weeks of treatment with a 4% glycolic acid formulation twice daily was employed to evaluate 1) epidermal morphology and thickness of the SC, (2) the lamellar body and SC lipid bilayer organization, and (3) desquamative events based on degradation of desmosomes. TEWL values and SC hydration were recorded prior to and at the end of the study. Electron microscopy revealed no ultrastructural changes in the nucleated layers of the epidermis. The lamellar body (LB) secretory system in the stratum granulosum (SG), and intercellular lipid lamellae in the SC in both vehicle- and glycolic acid-treated samples were comparable to normal human SC. Within the SC, enhanced desmosomal breakdown, promoting loss of cohesion and desquamation, was restricted to the stratum disjunctum while desmosomes of the stratum compactum were unaffected. Treated areas displayed histologically, a more compact appearing SC. TEWL values remained unchanged in glycolic acid- and vehicle-treated skin. Our findings indicate that the barrier structures of the SC are not disrupted by glycolic acid formulations at the concentration used. One of the mechanism of action of AHA on the SC seemed to be a „targeted“ desmosomal (corneosomal) action without compromising the barrier structures of the skin. Received: 20 November 1996     

Action of trypsin on human plantar stratum corneum

Summary Incubation of human plantar stratum corneum (SC) with trypsin at various pH suppressed the typical keratin pattern in the cytoplasm of the horny cells and disclosed tonofilaments and desmosomal attachment plates as they are seen in living keratinocytes. Tonofilaments were 62–75 Å wide and showed a 100–120 Å periodicity. This effect was non-specific since it was also obtained by incubation of SC with citric acid or sodium citrate, but it was not due to hydration alone. Partial acantholysis was obtained by incubation with trypsin followed by citric acid. After simultaneous action of trypsin in sodium citrate and in citric acid, cell membranes were separated from the cytoplasm and many of them were broken around desmosomes with subsequent isolation of desmosomes. The role of trypsin in this effect was uncertain. These findings strongly suggest that the filamentous network built up by living keratinocytes remains almost unchanged during the keratinization process although no longer visible under E.M.Clinique de Dermatologie, Faculté de Médecine     

Intermediate filaments and desmosomal plaque proteins in testicular seminomas and non-seminomatous germ cell tumours as revealed by immunohistochemistry

Summary Seminomas and non-seminomatous testicular germ cell tumours were studied for the presence of cytokeratin and vimentin filaments and desmosomes using immunohistochemical methods. In the majority of the classical seminomas and in seminomatous areas of mixed tumours most tumour cells appeared to lack cytokeratin filaments. Some seminomas contained a focally variable proportion of cells exhibiting cytokeratin-positive structures while other cases contained only few seminoma cells with a well developed fibrillar cytokeratin network. Gel electrophoresis of cytoskeletal proteins from microdissected regions revealed cytokeratin polypeptides nos. 8 and 18 typical of simple epithelia. In one seminoma, however, all, or almost all, tumour cells contained cytokeratin filaments. This finding is in line with the assumption of transitional forms between seminoma and embryonal carcinoma. Despite the lack - or variable expression - of cytokeratin filaments most seminoma cells contained desmosomes, although often few in number and irregularly distributed at the circumference of the cells. Loosely arranged and often very sparse vimentin fibrils were found in many, but not all seminoma cells. Double label immunofluorescence microscopy suggested that the majority of desmosomes was associated with intermediate filaments of the vimentin type. In contrast, in carcinoma cells of malignant teratomas, in well differentiated epithelial cells of intermediate-type malignant teratomas and in trophoblastic cells present in trophoblastic-type malignant teratomas cytokeratin filament bundles as well as desmosomes were decorated. The arrangement and density of the cytokeratin filament skeleton and of desmosomes varied with degree of maturation of the tissue. The most regular distribution and intensive staining of cytokeratin filaments and desmoplakin was found in mature tissues. Vimentin was demonstrated in mesenchymal areas and stroma cells. The results show that seminomas are distinguished from most other germ cell and non-germ cell tumours by the presence of true desmosomes together with scanty vimentin filaments in most tumour cells. In addition, they indicate that seminoma cells can be heterogenous in their cytoskeletal complement and may include cells with cytokeratin expression, indicative of a multi-potential character of the initially transformed cell(s).Supported in part by Fonds Zur Förderung der wissenschaftlichen Forschung (grant No. 4708 to H.D) and by the Deutsche Forschungsgemeinschaft (grants Mo 345/3 and Fr 308-17)     

Sequential changes in intercellular junctions between hepatocytes during the course of acute liver injury and restoration after thioacetamide treatment

Sequential changes of gap junctions (GJs), tight junctions (TJs) and desmosomes (DSs) between hepatocytes during restorative proliferation were studied in rats after a single intraperitoneal administration of 200 mg/kg thioacetamide (TAA). Antibody against connexin 32 was used to demonstrate GJs; simultaneously the changes in TJs and DSs were studied using antibodies against 7H6 protein and desmoplakins. Propidium iodide and bromodeoxyuridine were used to recognize necrotic and proliferative cells. GJs were evenly distributed in early necrotic hepatocytes at 16 h after TAA treatment, then disappeared from necrotic and surrounding cells at 24 h. At 48 h, GJs had disappeared completely from hepatocytes in whole liver lobules, while many hepatocytes were heavily labelled with BrdU. At 72 h, GJs reappeared, firstly in perinecrotic areas. At 96 h after treatment, when the injured areas had disappeared and restorative proliferation ceased, GJs were distributed evenly throughout the lobules. Immunohistochemical observation of GJs in centrilobular, perinecrotic and periportal areas after TAA-induced hepatic necrosis was confirmed by counting the number of connexin-32-positive spots in the respective areas. TJs and DSs disappeared from necrotic cells at 24 h, but then increased between 24 and 48 h in perinecrotic areas, though the increased intensity of these junctions was more evident at 48 h. At 72 h, localization of TJs and DSs returned to normal. These results suggest that during the course of acute hepatic injury, GJs (cell-cell communication) behave differently from other intercellular junctions.     

胸膜恶性间皮瘤和转移性肺腺癌的微绒毛,桥粒超微结构形态测量研究

本文研究结果表明,应用超微结构形态测量其微绒毛、桥粒有助于胸膜恶性间皮瘤和转移性肺腺癌的鉴别。16例胸膜恶性间皮瘤平均微绒毛长宽比值(L/W)为11.76。相反,10例转移性肺腺癌平均微绒毛L/W为5.22,两者之间具有显著差异(P<0.001)。本文测量了16例恶性间皮瘤和10例转移性肺腺癌的桥粒长度,两组平均桥粒长度差异不十分显著,但是,所有16恶性间皮瘤的桥粒长度均有大于1.5μm,相反,10例转移性肺腺癌无1例桥粒长度超过1.5μm,表明恶性间皮瘤具有长的桥粒,而转移性肺腺癌则缺乏长的桥粒。