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Biomedical subjects

R A Eady

Publications and source records attributed to R A Eady.

At least 19 recordsLinked to original sources
PubMed1992

A mutation in the conserved helix termination peptide of keratin 5 in hereditary skin blistering.

In the hereditary blistering condition epidermolysis bullosa simplex, the skin blisters on trauma following rupture of epidermal basal cells. Clinical variations range from severely incapacitating, especially in early childhood, to mild forms that may not even present clinically. Dowling-Meara epidermolysis bullosa simplex is characterized by clusters of epidermal blisters and keratin clumping in the cytoplasm; recent reports describe potentially causal mutations in keratin 14 (refs 2, 3). Here we describe a 'complementary' mutation at the other end of the other keratin expressed by these cells (K5, coexpressed with K14), a change from a Glu to a Gly in the helix termination peptide, detected by altered antibody binding and confirmed by sequencing using the polymerase chain reaction. The two conserved helix boundary peptides are predicted to be essential for filament assembly, and the requirement for two complementary (type I and type II) keratins is absolute. Epidermolysis bullosa simplex diseases demonstrate the function of the keratin cytoskeleton in resisting compaction stresses which otherwise lead to cell lysis.

Amino Acid Sequence↗
PubMed1992

Selective involvement of keratins K1 and K10 in the cytoskeletal abnormality of epidermolytic hyperkeratosis (bullous congenital ichthyosiform erythroderma).

Aggregation of tonofilaments within epidermal keratinocytes is a characteristic histologic feature of epidermolytic hyperkeratosis including the generalized form known as bullous congenital ichthyosiform erythroderma. The histologic distribution and the keratin composition of the altered tonofilaments were investigated to determine whether the aggregation was specific to any particular keratin(s). Skin samples from seven patients and one mid-trimester fetus with generalized epidermolytic hyperkeratosis, and from one patient with a localized or "nevoid" form of epidermolytic hyperkeratosis, were analyzed by using various microscopical and immunocytochemical methods. A conjunctival sample and cultured epidermal keratinocytes from one patient with generalized epidermolytic hyperkeratosis were also examined by electron microscopy and immunocytochemistry. Ultrastructurally, tonofilament aggregates were distributed within the suprabasal stratified epithelial cell layers of the epidermis, of the infundibular part of outer root sheaths, and of the sebaceous ducts and sweat ducts, selectively following the known distribution pattern of keratins K1 and K10. The abnormal tonofilaments were not found in any other cutaneous epithelia, in conjunctival epithelium, or in cultured keratinocytes, where K1 and K10 are absent or only minimally expressed. Immunoelectron microscopy showed that among the keratins detected in suprabasal epidermolytic hyperkeratosis epidermis (K1/K5/K10/K14/K16), the aggregated tonofilaments predominantly expressed K1 and K10 rather than other keratins. These results suggest that the keratin filament abnormality in epidermolytic hyperkeratosis principally involves K1 and K10 and raise the question whether epidermolytic hyperkeratosis might be primarily a disorder of one or both of these keratins.

Adolescent↗
PubMed1992

Intracellular expression of type VII collagen during wound healing in severe recessive dystrophic epidermolysis bullosa and normal human skin.

The ability of keratinocytes to synthesize basement membrane components in vivo during wound healing in normal human skin and in severe recessive dystrophic epidermolysis bullosa (RDEB) was investigated. Indirect immunofluorescence using anti-type VII collagen (VIIc, recognizing the globular non-helical component of the molecule), anti-type IV collagen, anti-laminin and bullous pemphigoid antisera, was performed on biopsies of intact skin and of healing skin taken between 7 and 14 days after dermatome injury (upper to mid-dermal wounding) in eight patients with severe RDEB and in seven normal subjects. Baseline anti-type VIIc immunofluorescence showed completely absent staining of the epidermis, dermis and dermo-epidermal junction in severe RDEB samples, and bright linear dermo-epidermal junction fluorescence in normal human skin. In 5/5 normal human skin samples taken 9-12 days post-wounding, some type VIIc expression was noted within basal cells as well as in a continuous or interrupted linear distribution at the basement membrane zone. In all the severe RDEB biopsies sampled between days 10 and 13 (5/5), anti-VIIc fluorescence was also seen with varying intensity within basal and lowermost suprabasal cells, and in one day 14 sample at the dermo-epidermal junction. Low levels of intracellular type IVc were seen in both groups, but only in those samples taken 7-9 days after injury; later biopsies showed only continuous dermo-epidermal junction staining. Linear basement membrane zone labelling with laminin and bullous pemphigoid antisera was seen in all samples in both sets of subjects, even at day 7, but there was no detectable intracellular antisera staining.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Epidermolysis bullosa simplex (Dowling-Meara). A clinicopathological review.

The clinicopathological features of 22 cases of the Dowling-Meara form of epidermolysis bullosa simplex (DM-EBS) (11 males, 11 females; aged 5 days-46 years) were reviewed using data collected over a 10-year period. All cases presented clinically within the first 5 days of life. Early blisters were often large (up to 5 cm in diameter), and were mostly acral and particularly periungual. Some cases presented with more widespread erosive skin changes, and two neonates with extensive skin involvement died as a result of overwhelming sepsis. After the neonatal period a different pattern of blistering occurred with more proximal haemorrhagic, herpetiform clusters of blisters. Central healing with recurrent blistering at the margins of these areas was frequently noted. Other physical signs included varying degrees of intra-oral blistering, nail shedding, nail dystrophy, minor scarring, palmo-plantar keratoderma, a lack of seasonal variation and improvement during later childhood. The underlying pathological mechanism in DM-EBS is basal cell cytolysis, or rarely acantholysis, in association with tonofilament (TF) clumping. TF clumping was found in lesional, perilesional and some non-lesional skin, suggesting that the tonofilament abnormality may be of primary aetiological significance in DM-EBS. TF clumping may be due to specific keratin abnormalities because the altered TF were found in a distribution similar to the known distribution of the basal cell keratins, K5 and K14. The level of blistering was invariably very low within the epidermal basal layer and often less than 0.5 microns above the basement membrane. We conclude that DM-EBS is a distinct, and probably under-recognized genodermatosis which tends to have a good prognosis. However, the disease can occasionally be severe, especially during the neonatal period, when it may be confused with junctional or severe recessive dystrophic EB. Electron microscopy is the best means for demonstrating the characteristics cytoskeletal disorder and confirming the diagnosis.

Adolescent↗
PubMed1992

Expression of mutant p53 gene in squamous carcinoma arising in patients with recessive dystrophic epidermolysis bullosa.

Epidermolysis bullosa, a rare genodermatosis, is characterized by increased skin fragility manifest as blistering and sometimes accompanied by scarring. The latter is particularly severe in the recessive dystrophic variant and may be complicated by the development of squamous carcinoma in up to 30% of patients. We have studied 23 such tumours in six patients with this variant, with an anti-serum to p53 protein. Twenty-six per cent of the squamous carcinomas labelled positively for mutant-type p53 protein. This low figure, however, reflects the large number of well-differentiated tumours in this series, where 14 out of 15 were negative. In the moderate to poorly differentiated examples the positivity rate was 63%. Of the three patients in the latter category, one has died from disseminated tumour and another has widespread metastases. The findings support the hypothesis that mutant p53 protein expression correlates with poorer tumour differentiation. They also suggest a possible correlation between p53 protein expression and tumour behaviour.

Carcinoma, Squamous Cell↗
PubMed1992

Epidermolysis bullosa: to split and to clump.

During the past few years various proteins have come to the forefront as underlying the structural abnormalities of different forms of epidermolysis bullosa. Only very recently has linkage been established between certain major forms of epidermolysis bullosa and the genes encoding some of these proteins, and mutations of these genes identified. The stage will soon be set for providing a new and rational basis for a better understanding of the pathogenesis of epidermolysis bullosa, for improving diagnosis, including prenatal testing, and for devising new approaches to treatment.

Chromosome Mapping↗
PubMed1992

Mitten deformity in severe generalized recessive dystrophic epidermolysis bullosa: histological, immunofluorescence, and ultrastructural study.

Light and electron microscopy and indirect immunofluorescence techniques were used to study the nature of the mitten deformity in five adult patients with severe generalized recessive dystrophic epidermolysis bullosa undergoing release of hand and finger contractures. Although the mitten appeared largely to be clinically separated from the underlying fixed digits, histology showed mostly normal keratinocytes beneath a thickened stratum corneum. The lower margin of the mitten was formed just below the lamina densa of the basement membrane, at a level similar to that of the usual blister formation in this condition. No anchoring fibrils and only a few distinct dermal structures were noted. A substantial portion of the mitten, however, consisted of necrotic keratinocytes without an intact basement membrane. This finding suggests that the mitten is not suitable for use as an epidermal autograft and confirms the rationale for taking split thickness skin grafts to close skin defects in patients with recessive dystrophic epidermolysis bullosa undergoing plastic surgery.

Adult↗
PubMed1992

Epidermolysis bullosa complicated by squamous cell carcinoma: report of 10 cases.

Epidermolysis bullosa (EB) refers to a group of hereditary mechano-bullous conditions, many of which are associated with chronic scarring. Several forms of the disease have been reported in association with cutaneous malignancy. We present a series of 10 EB patients (eight generalised recessive dystrophic EB, one dominant dystrophic EB, one non-lethal junctional EB) aged 24-55 years with a total of 29 squamous cell carcinomas (SCC). Three patients died from metastatic disease associated with invasive, poorly differentiated SCC. Six cases had multiple primary SCC, including three patients with simultaneous multifocal disease. Twenty-eight of the 29 SCC arose on the limbs. Histology revealed that most of the SCC were well or moderately differentiated (22/29). Unusual histological findings included two verrucous SCC, as well as a spindle cell (angiosarcoma-like) SCC. Most of the SCC developed in areas of chronic non-healing ulceration (10/29) or longstanding hyperkeratotic crusting (14/29). The dermis around or beneath the carcinomas was densely scarred, more so than in non-malignant areas. In some cases it was difficult to distinguish the clinical appearances of certain areas of chronic ulceration, scarring, and crusting typical of dystrophic EB from many of the SCC. This study underlines the need for constant vigilance for the development of carcinomas in this group of patients, the occasional diagnostic difficulty, and the potential for metastasis.

Adult↗
PubMed1992

The use of silver-enhanced 1-nm gold probes for light and electron microscopic localization of intra- and extracellular antigens in skin.

We used colloidal gold (1-nm diameter) with silver enhancement, in conjunction with a low-temperature post-embedding immunolabeling technique, to localize several antigens in normal skin at both the light and the electron microscopic level within the same tissue blocks. Normal skin subjected to cyrofixation and cryosubstitution and embedded in Lowicryl K11M was used as a substrate. Semi-thin sections (1 micron) were incubated in primary antibody (against epidermal basement membrane zone associated antigens and two keratin sub-types), biotinylated secondary antibodies, and then in 1-nm gold-conjugated streptavidin. Finally, the 1-nm gold label was enhanced using silver staining. Labeling of both basement membrane and keratin antigens was well demonstrated, and the area in the semi-thin sections showing the best structural preservation and the greatest intensity of immunolabeling was used to identify the part of the block to be used for ultra-thin sectioning. Ultra-thin sections were treated using a similar procedure to that employed for semi-thin sections. The labeling with silver-enhanced 1-nm gold probes was intense and readily visible by electron microscopy, even at low magnification. We have found this technique to have a high degree of specificity and sensitivity for labeling both intra- and extracellular antigens in skin, with the added advantage of providing the means for studies at both light microscopic and electron microscopic level.

Antibodies↗
PubMed1991

Revised clinical and laboratory criteria for subtypes of inherited epidermolysis bullosa. A consensus report by the Subcommittee on Diagnosis and Classification of the National Epidermolysis Bullosa Registry.

Inherited epidermolysis bullosa encompasses a number of diseases, with the common finding of blister formation after minor mechanical trauma to the skin. In some forms significant, if not eventually fatal, extracutaneous disease activity may occur. In recent years application of newer technologies has contributed substantially to an overall understanding of this collection of inherited diseases. Concurrently, many new phenotypes have been recognized, in part the result of ongoing prospective patient registries in the United States and abroad. Unfortunately, this has resulted in a massive literature that may appear to be confounded by seemingly excessive or arbitrary subdivision of epidermolysis bullosa variants. With these concerns in mind a subcommittee was established by the National Epidermolysis Bullosa Registry to summarize the current literature and to make recommendations as to the best clinical and laboratory criteria for the practical diagnosis and subclassification of patients with inherited epidermolysis bullosa.

Epidermolysis Bullosa↗
PubMed1991

Epidermolysis bullosa simplex (Dowling-Meara type) is a genetic disease characterized by an abnormal keratin-filament network involving keratins K5 and K14.

The distribution and morphology of tonofilament (TF) clumps were examined by light and electron microscopy in skin samples from a total of 17 patients with the Dowling-Meara (DM) form of epidermolysis bullosa simplex (EBS). TF clumps extending from the basal to the upper-spinous epidermal layer were seen in all lesional skin samples and in the majority of peri-lesional and non-lesional skin samples. TF clumps were also noted in adnexal epithelia, including outer hair root sheaths, sweat ducts, and sebaceous glands. Cultured keratinocytes from two patients also demonstrated characteristic TF clumps. All these epithelial cells have in common their expression of the keratin pair K5 and K14. Post-embedding immunogold electron microscopy using antibodies to K5, K14, and K10 showed similar expressed keratins in DM-EBS skin from four patients compared with normal skin, with K5 and K14 predominantly in the basal cell layer and K10 in the suprabasal layers. The clumped TF in DM-EBS samples were labeled strongly with anti-K5 and K14 antibodies in the basal and suprabasal layers. In contrast, the suprabasal clumps were only slightly reactive with anti-K10 antibodies and labeling was usually restricted to the periphery of the clumps. We conclude that DM-EBS is associated with an intrinsic abnormality of the keratin-filament network involving the K5 and K14 pair that is likely to result in impaired resistance of basal epidermal cells to external shearing forces, leading to the characteristic intraepidermal blisters. DM-EBS may become the first genetic skin disease to be recognized as having a specific keratin abnormality.

Adolescent↗
PubMed1991

Human monoclonal anti-basement membrane zone antibodies derived from virally transformed lymphocytes of a patient with bullous pemphigoid recognize epitopes associated with hemidesmosomes.

The purpose of this study was to determine the ultrastructural localization of the epitopes recognized by two human monoclonal antibodies designated 5E and 10D, that were derived from virally transformed lymphocytes from a patient with bullous pemphigoid (BP). Previous immunoblotting showed that 5E but not 10D reacted with a 230-kDa protein in extracts of normal human skin. In the present study, indirect immunofluorescence showed that both 5E and 10D bound to the epidermal side of 1 M NaCl-separated normal human skin. Immunoperoxidase electron microscopy showed that 5E and 10D formed discontinuous focal deposits along the basal region of the epidermal basal cells in normal human skin in a similar localization to that seen with whole BP sera. Post-embedding immunogold electron microscopy demonstrated binding of both monoclonal antibodies to the intracellular components of hemidesmosomes. As far as we are aware, 5E and 10D are the first monoclonal antibodies to be described that recognize epitopes of BP antigen associated with hemidesmosomes and should serve as useful probes for future studies.

Antibodies, Monoclonal↗
PubMed1991

Detection of a novel basement membrane antigen by GDA-J/F3 anti-human sperm fibrous sheath monoclonal antibody.

Basement membrane zones (BMZ) of human epithelia were stained with GDA-J/F3 monoclonal antibody, which was originally raised against sperm cells. Using indirect immunofluorescence and immunoperoxidase techniques, the antibody reacted with the BMZ of stratified squamous epithelia (skin and its appendages, tongue, lip, oesophagus and cervix). It also stained the BMZ of trachea, nasal ciliated mucosa, some mammary ducts of lactating and resting breast, amnion and ureter but failed to react with that of stomach, ileum, colon, rectum, kidney, liver, fallopian tube, lung or their blood vessels. In testes, the antibody did not react with the BMZ of the seminiferous tubules although the sperm tails were stained. Split-skin immunofluorescence and immunoelectron microscopy localized GDA-J/F3 antigen to the inferior border of the lamina densa of the BMZ. In human foetuses, the epidermally associated antigen was detected at an estimated gestational age of 9 weeks, and in the amnion at 15 weeks. The antibody reacted with tissues from monkey but not from mouse, rat, cow or pig suggesting the late appearance of the antigen during evolution. Although the GDA-J/F3 was difficult to characterize biochemically, its tissue distribution, ontogeny and ultrastructural localization suggests that this antigen may be a type VII collagen-associated protein, whose expression is altered in recessive dystrophic epidermolysis bullosa. This disease could represent abnormalities in type VII collagen structure, assembly, transport or interaction with associated proteins.

Animals↗
PubMed1991

Metastatic squamous cell carcinoma resembling angiosarcoma complicating dystrophic epidermolysis bullosa.

We report a patient with generalized recessive dystrophic epidermolysis bullosa (RDEB) who developed 3 squamous cell carcinomas. The tumours appeared simultaneously at acral sites on both upper limbs and were poorly differentiated. Despite surgery and radiotherapy the patient died from metastatic disease within 6 months of presentation. This case highlights many of the typical features of this complication of RDEB, including the overall poor prognosis. Of particular interest was the histology of one of the tumours which caused diagnostic difficulties: haematoxylin and eosin staining suggested an angiosarcomatous pathology, but the use of immunocytochemistry proved that the tumour was a squamous cell carcinoma in origin.

Carcinoma, Squamous Cell↗