Search PubMed⌕ Search

Biomedical subjects

A W Barrett

Publications and source records attributed to A W Barrett.

At least 37 records · Page 2Linked to original sources
PubMed2002

A clinicopathologic and immunohistochemical analysis of melanotic neuroectodermal tumor of infancy.

OBJECTIVE: The purpose of this study was to review the features of 8 cases of melanotic neuroectodermal tumor of infancy (MNTI) of the jaws with respect to the expression of NB84, CD99, PGP 9.5, specific cytokeratins, and Ki-67, markers not previously reported in this entity. STUDY DESIGN: A clinicopathologic and immunohistochemical analysis of MNTIs in 8 children was undertaken. RESULTS: Patients were aged 2(1/2) months to 14 months. Seven were males. Seven lesions affected the maxilla. Microscopically, collections of larger, melanocyte-like cells were admixed with smaller, neuroblast-like cells. All MNTIs contained melanin; although most showed cellular atypia, mitoses were infrequent (<2 per 10 high-power fields). However, in one lesion in which the melanocyte-like cells appeared less differentiated, 7 mitoses per 10 high-power fields were counted. The larger cells expressed cytokeratins 7 (4/8), 8 (8/8), 18 (6/8), and 19 (3/8); PGP 9.5; neuron-specific enolase (6/8); S100; HMB45; and chromogranin A (2/8). The small cells expressed CD56 (7/8), neuron-specific enolase (7/8), synaptophysin (3/8), PGP 9.5 (3/8), and chromogranin A (2/8). No MNTIs expressed NB84. The most mitotically active tumor was the only one to show membrane expression of CD99 (by both cell populations), have a detectable Ki-67-positive fraction (25% in both the large- and small-cell components), behave aggressively, and require bilateral maxillectomy. All other MNTIs responded to local excision, and none metastasized. CONCLUSIONS: Most MNTIs are benign and respond to conservative excision. Histology is an unreliable means of predicting clinical behavior, but this study has identified some morphologic and phenotypic features that may indicate a more aggressive lesion.

12E7 Antigen↗
PubMed2001

The distribution of retinaldehyde dehydrogenase-2 in rat and human orodental tissues.

Retinoic acid is an important signalling molecule in embryological development and continues to be important in the adult animal because it modulates growth and differentiation in many epithelial tissues. The distribution of the enzyme retinaldehyde dehydrogenase-2 (RALDH 2), which is involved in the synthesis of retinoic acid, was studied using immunocytochemical techniques in: (1) the developing orodental region of rats aged between 15 days in utero and 6 months; and (2) in archival human autopsy material consisting of abdominal skin and mucosa from various regions of the mouth. In developing tooth germs, RALDH 2 was absent in the enamel organ and dental papilla, its presence only being noted at the periphery of the dental follicle adjacent to parts of the developing alveolar crypt. In adult teeth, the presence of RALDH 2 was limited to blood vessels in the periodontal ligament. In embryos, the connective tissue beneath the nasal epithelium and the meninges stained strongly positively for RALDH 2, as did the connective tissue beneath nasal epithelium in an adult rat. Both keratinized and non-keratinized human oral epithelia and abdominal skin stained positively for RALDH 2. Staining was present throughout the stratified epithelium, except in the keratinized layer and in the basal layer associated with the dorsal surface of the tongue. In addition, the adnexia as well as the ductal lining of mucous glands stained positively for RALDH 2.

Adult↗
PubMed2001

Cellular neurothekeoma of the oral mucosa.

Cellular neurothekeoma is an unusual benign neoplasm which, despite its name, is of uncertain origin. This report describes a cellular neurothekeoma of the cheek mucosa, the first at this site. The tumour presented in a 29-year-old man as a discrete mucosal thickening. Histology showed a generally well circumscribed, but unencapsulated, solid tumour which replaced the entire lamina propria and permeated between minor salivary glands and bundles of striated muscle in the submucosa. There was a sub-epithelial Grenz zone. The tumour was composed of nodules of pale, epithelioid cells separated by fascicles of spindle cells, with smaller strands and nests superficially. The nuclei were vesicular and, though mainly bland, occasionally atypical. The stroma was moderately infiltrated by mixed chronic inflammatory cells. Prominent nerves and blood vessels were seen at the periphery of the lesion, and neoplastic cells were noted within intact striated muscle fascicles. With immunohistochemistry, all the neoplastic cells strongly expressed NKI/C3, synaptophysin, neurone-specific enolase and vimentin, some expressed smooth muscle actin and PGP 9.5, but all were negative for S100, factor XIIIa, CD34, CD56, CD57, CD68, chromogranin A, desmin, epithelial membrane antigen and von Willebrand factor. The origin of the lesion is thus speculative. It was, however, completely excised and in 12 months there has been no recurrence.

Adult↗
PubMed2000

An immunohistological study of cytokeratin 20 in human and mammalian oral epithelium.

Cytokeratin (CK) 20 is a low molecular-weight intermediate filament reportedly expressed only by benign and malignant gastrointestinal epithelium, urothelium and Merkel cells. The main aims here were to map its expression in normal oral mucosa of humans and other mammals, and to determine whether it was expressed by abnormal human oral epithelium. Salivary and odontogenic epithelium were also analysed. An immunoperoxidase method was used on wax-embedded and cryostat sections. In addition, double-labelling experiments were undertaken to determine the association between CK 20 expression and that of CK 8/18 or S100 protein. Normal human oral mucosa from four sites, together with abdominal skin, was studied in autopsy samples from 32 individuals. CK 20-positive, basally situated, round or angular cells, consistent with Merkel cells, were recorded in 24/32 (75.0%) samples of mandibular gingiva, 25/32 (78.1%) samples of hard palate, 7/32 (21.9%) samples of buccal mucosa, 0/32 samples of lateral border of tongue, and 2/32 (6.3%) samples of abdominal skin. Double-labelling showed that all CK 20-positive Merkel cells also expressed CK 8/18 and S100. The only other cells to express CK 20 were human taste buds. There was no expression by dysplastic or invasive oral epithelium from biopsy samples. Colonic mucosa showed luminal-cell positivity in man, marmoset, ferret, rabbit and guinea-pig, but oral mucosa was universally negative in non-human species. It is concluded that in oral mucosa CK 20 is a specific marker of Merkel cells and taste buds, that Merkel cells are more frequently present in keratinized than non-keratinized oral mucosa, that CK 20-positive Merkel cells are also S100-positive, that there may be interspecies variations in CK 20 polypeptide composition and that, by contrast to urothelium, CK 20 has no value in the diagnosis of oral epithelial dysplasia.

Adult↗
PubMed2000

The preparation of periapical lesions for flow cytometry.

AIM: To devise an optimal protocol and to analyse the leucocyte composition of periapical (PA) lesions by flow cytometry. METHODOLOGY: PA lesions were mechanically agitated, with and without proteolysis. This was with either 0.2% collagenase alone, or in combination with 0.02% DNA-ase in serial incubations until all tissue was digested. The efficacy of each method was assessed by counting total cell yield and cell viability. Phenotype stability was gauged by the percentage of peripheral blood leucocytes (PBL) which expressed CD45RB, CD3, CD20, CD4 and CD8 before and after mechanical and collagenase treatment. RESULTS: Disaggregation of PA lesions was superior if collagenase was present, but cell clumping was problematic unless the DNA-ase was also added, and serial digestion with this combination produced optimal cell yield and viability. Nevertheless, the total number of cells released rarely exceeded 105, though viability was in excess of 80%. Mechanical agitation and proteolysis adversely affected PBL phenotypes, but collagenase digestion limited to 10 min caused least damage. Flow cytometric analysis of disaggregated PA lesions failed to identify more than 7.9% (mean, range 6-10%) CD45RB + cells. CONCLUSIONS: Because of the necessity for single cell suspensions, flow cytometry is not easily applied to the analysis of leucocytes in PA lesions, and further refinements in tissue disaggregation and cell preparation are required.

Antigens, CD↗
PubMed2000

Superficial arteriovenous hemangioma of the oral cavity.

OBJECTIVE: Superficial arteriovenous hemangioma (AH) is a benign vascular lesion that often affects the head and neck, but only 3 histologically proven intraoral lesions have been previously reported. The aim of this study was to analyze the clinical and histologic features of 36 oral AHs from 35 patients. STUDY DESIGN: All vascular lesions, other than pyogenic granulomas, accessioned between 1952 and 2000 were retrieved, and clinical details were gleaned from the request forms or, when available, from the case notes. Histologic sections stained with hematoxylin-eosin were reviewed, and all selected cases were stained for smooth muscle actin and elastin. RESULTS: The age range was 12 to 90 (mean, 53 years; median, 59). Of all patients, 54% were female. All the lesions were solitary. The labial mucosa or vermilion was affected in 17 (49%) patients, the tongue in 5, the hard palate and cheek mucosa in 4 each, the gingiva or alveolar mucosa in 3, and the floor of the mouth in 1. Clinical presentation was most often a raised lesion smaller than 20 mm. Duration ranged from months to many years. Four lesions recurred. The consistent histopathologic feature was an unencapsulated mass of blood vessels located in the lamina propria, the submucosa, or both, but 3 patterns could be discerned. The most common (in 44% of cases) comprised a diffuse mixture of thick-walled and thin-walled vessels in variable proportions. The second pattern (42%) showed a lobular arrangement of smaller vessels of uniform wall thickness, sometimes associated with an arteriole. The remaining 14% showed a tortuous pattern of angular, branching, thick-walled vessels lacking inner elastic laminae; one lesion showed both this pattern and the first pattern, one showed both the lobular morphology and the third pattern. Of the patients with the lobular arrangement, 64% were female. Smooth muscle actin was a major component of the lesional vessel walls regardless of thickness, but although most contained some fibrillary elastin, none had inner elastic laminae as prominent as those seen in adjacent true arteries. All AHs contained plump endothelial cells, and mast cell numbers were increased. CONCLUSIONS: The etiology of AH is uncertain; endocrine and inflammatory stimuli may activate an underlying vascular malformation. Some lesions, especially those in younger patients, may be true hamartomas.

Actins↗
PubMed1999

Oral plasmablastic lymphoma in previously undiagnosed HIV disease.

Non-Hodgkin's lymphoma is the second most common HIV-associated malignancy. This report details a case of the recently described entity plasmablastic lymphoma of the mouth in a patient who was later found to have severe HIV disease. The tumor manifested as a large ulcerated mass of the left maxillary alveolus, causing bony destruction and tooth mobility. Histologic examination of lesional tissue revealed a lymphoid tumor with a high proliferation rate containing lymphoplasmacytoid cells that were reactive to the plasma cell marker VS38c but not to CD20 or CD79a; these are features of the recently reported non-Hodgkin's lymphoma termed plasmablastic lymphoma. This is only the second report of an unusual tumor that has a predilection for the orofacial tissues.

Adult↗
PubMed1999

Oral mucosal leishmaniasis as a presenting feature of HIV infection and its management.

Leishmaniasis is a chronic parasitic protozoal disease transmitted by sandfly vectors and is endemic in some regions of South America, Asia, Africa and Mediterranean countries. This case report describes a British patient who presented with oral mucosal leishmaniasis and in whom it was also the first sign of HIV disease. We believe it is the first reported case of isolated oral mucosal leishmaniasis as a presenting feature of otherwise unknown HIV infection.

Animals↗
PubMed1998

Immunolocalization of cytokines and growth factors in oral submucous fibrosis.

Oral submucous fibrosis (OSF) is a chronic fibrotic disease of the oral cavity and oropharynx characterized by fibroelastic change in the mucosa which leads to progressive inability to open the mouth. The inflammatory cells in the lesional tissue consist mainly of T lymphocytes, with a high CD4:CD8 ratio, and major histocompatibility complex (MHC) class II expressing antigen-presenting cells. Cytokines and growth factors produced by inflammatory cells within the lesion may promote fibrosis by inducing proliferation of fibroblasts, upregulating collagen synthesis and downregulating collagenase production. The authors used a three-stage immunoperoxidase technique to investigate the expression of interleukin alpha (IL-1alpha) and beta, IL-6 interferon (IFN)-alpha, beta and gamma, transforming growth factor beta (TGF-beta), platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) in frozen sections of OSF and compared it with that in normal buccal mucosa. The expression of cytokines and growth factors in normal tissues was consistent with their well known distribution and cell of origin, but the intensity and distribution in OSF were all, with the exception of IFN-alpha and gamma, upregulated with strong expression in both the epithelium and underlying connective tissue. IFN-alpha showed a similar pattern of staining in both normal mucosa and OSF. IFN-gamma showed little or no expression in most lesional tissues, suggesting an innate deficiency or downregulation of this cytokine. The general increase in pro-inflammatory cytokines and growth factors, and reduced production of IFN-gamma, may play an important role in the pathogenesis of OSF.

Adolescent↗
PubMed1998

Interspecies variations in oral epithelial cytokeratin expression.

The aim of this study was to determine the degree to which the epidermis and oral epithelium of species other than man express cytokeratin (CK) intermediate filaments, which are markers of epithelial differentiation. Fixed, wax-embedded samples of skin, buccal mucosa and gingiva from rhesus monkey, marmoset, cow, sheep, pig, ferret, hamster, axolotl and trout were tested for CK expression using a panel of antihuman CK antibodies and an immunoperoxidase procedure. Human skin and oral mucosa were also stained to act as positive control. The results showed that antihuman CK antibodies stained animal tissues, but the patterns of staining were not always identical to the established human CK profile. Of particular interest was the expression of CK18, typically only detected in 'simple' epithelium in man, in bovine, ferret and hamster stratified epithelium from different sites. However, there was evidence of variable anti-CK antibody cross-reactivity, both as a result of intrinsic variations in CK polypeptide structure and as artifacts of fixation. We conclude that some CK are conserved between species, but that biological variables, for example local functional requirements, and technical factors affect the results. These considerations need to be borne in mind in animal studies of epithelial differentiation employing CK immunohistochemistry. Biochemical characterisation is ultimately necessary to determine specific differences between human and animal CK.

Ambystoma↗
PubMed1998

The frequency of fungal infection in biopsies of oral mucosal lesions.

OBJECTIVE: To determine the frequency of fungal infection in biopsies of oral mucosal lesions. MATERIALS AND METHODS: Histopathology reports issued between 1991-1995 inclusive were reviewed. During this period, a single section of each mucosal biopsy had been stained using the periodic acid-Schiff (PAS) technique. RESULTS: A total of 223 (4.7%) biopsies contained PAS-positive fungi: 191 individuals were affected, 124 (64.9%) of whom were male. There was a significant (P < 0.01) positive association of fungal infection with moderate and severe epithelial dysplasia, median rhomboid glossitis and squamous papillomas. Where a subsequent biopsy was available, 21.9% dysplasias which were infected with fungi worsened in histological severity, as compared with 7.6% of dysplasias which were not infected at any stage. There was a significant negative association of fungal infection with benign fibrous overgrowths (P < 0.01), benign hyperkeratoses, lichenoid reactions and pyogenic granulomas (P < 0.05). The difference in frequency of infection between the tongue and other sites was also significantly higher (P < 0.01). CONCLUSIONS: There is a statistically significant association between histologically-determined fungal infection and epithelial dysplasia, and we recommend that a PAS stain be performed whenever oral epithelial dysplasia is diagnosed, especially in male patients. On histological confirmation of dysplasia, anti-fungal therapy should be considered in the management of these lesions.

Adolescent↗
PubMed1997

The immunohistochemical identification of human oral mucosal melanocytes.

With the aim of identifying melanocytes, 60 samples of wax-embedded palatal and buccal mucosa front 30 autopsies were analysed for expression of S100, HMB-45 and NKI/C3 in combination with a Masson Fontana stain. The counts of positive cells were compared with those derived from 3,4 dihydroxyphenylalanine (DOPA) staining in fresh samples of gingiva. Polyclonal antisera to S100 stained dendritic cells throughout the epithelium, but monoclonal antibodies to S100, HMB-45 and NKI/C3 labelled cells that were restricted to the basal layer, often in clusters with some sections negative. The mean counts of positive basal dendritic cells per millimetre basement-membrane length were 4.3 (polyclonal S100+. range 0-19). 0.8 (monoclonal S100+. range 0-7.3), 2.0 (HMB-45, range 0-17.8) and 0.9 (NKI/C3, range 0-14.9). Of the last three, HMB-45 produced the clearest and most specific staining. Counts of basal dendritic cells were significantly higher (p < 0.0005) with polyclonal antisera to S100 than with all other markers except DOPA but HLA-DR staining showed that Langerhans cells may also be located in the basal layer. The highest values were always in buccal mucosa, but statistically significantly so (p < 0.0005) only with polyclonal anti-S100. Basally located DOPA+ cells had a mean density of 4.6 per millimetre basement-membrane length, but in five cases DOPA also labelled suprabasal dendritic cells, presumably Langerhans cells. The mean basal DOPA+ values were significantly higher than those with monoclonal antibodies to S100. HMB-45 and NKI/C3 (p < 0.001). The variable cell counts suggest that S100, HMB-45 and NKI/C3 are markers of melanocytes in normal oral mucosa, but are not constitutively expressed and may be induced during function.

Adult↗
PubMed1997

Bilateral internal mammary artery atherosclerosis: a late complication of delayed repair of coarctation of the aorta.

A 58-year old patient who had undergone repair of aortic coarctation at 19 years of age, subsequently developed coronary artery disease requiring coronary artery bypass surgery. At operation both internal mammary arteries were found to be totally occluded with calcific atherosclerosis. We therefore advise that the internal mammary arteries should be assessed carefully in patients with similar past histories.

Aortic Coarctation↗
PubMed1997

Hybrid central giant cell granuloma and central odontogenic fibroma-like lesions of the jaws.

Ten lesions from eight cases are presented of a rare intra-osseous jaw lesion with the combined histological features of giant cell granuloma and central odontogenic fibroma. Lesions arose over a wide age range and presented as monolocular or multilocular radiolucencies with cortical expansion and, in one case, perforation. Two lesions recurred after curettage, one being eradicated by a second curettage and one by conservative excision. Histologically, zones of typical giant cell granuloma lay in a fibrous stroma containing islands, strands and clusters of epithelial cells. Islands often contained duct-like spaces or hyaline basement membrane globules. Trabeculae of osteoid were present in five lesions. Recurrent lesions showed features identical to the initial lesion, including recurrence of the prominent epithelial component. These features cannot be conclusively ascribed to a variant of either giant cell granuloma, central odontogenic fibroma or aneurysmal bone cyst, but the clinical features are slightly more suggestive of giant cell granuloma. Attention is drawn to the characteristic and potentially confusing histological appearances. The presence of giant cell granuloma-like areas in central odontogenic fibroma-like lesions is associated with an increased risk of recurrence following curettage.

Adolescent↗
PubMed1997

The structure of bovine periodontal ligament with special reference to the epithelial cell rests.

The aim of this study was to determine the structure of the bovine periodontal ligament, with special reference to epithelial cell rests (ECR) and their cytokeratin content. Periodontal ligament was obtained from bovine molar teeth and studied at both the light microscopic and electron microscopic levels. Cytokeratin content was determined using immunohistochemistry against a number of cytokeratin antibodies and specificity tested against bovine and human oral mucosa. Collagen fibril diameters and the area of a fiber bundle occupied by collagen were determined using a digital planimeter with a digitizing tablet. The majority of periodontal fibroblasts possessed considerable quantities of roughened endoplasmic reticulum, indicating rapid synthesis and secretion of collagen, but no intracellular collagen profiles were present. Endothelial cells showed Weibel-Palade bodies. Collagen fibril diameters showed a unimodal distribution with a mean collagen fibril diameter of 55.3 nm. The mean percentage area of the extracellular matrix occupied by collagen was 42%. Structurally, ECR were unusual in exhibiting large numbers of microvilli and conspicuous amounts of cytokeratin filaments. Bovine ECR showed a positive reaction to the pancytokeratin MNF116 (which reacts with the cytokeratins 5, 6, 8, 17, and probably 19), to PCK-26 (which reacts with the type II cytokeratins 1, 5, 6, and 8) and to cytokeratin 13. There was no reaction for cytokeratins 1, 4, 10, 11 and 18. Structurally, bovine periodontal ligament showed features common to other species. However, ECR in terms of both structure and cytokeratin content showed features indicative of important species differences which may have relevance when considering the etiology of radicular cysts.

Actin Cytoskeleton↗
PubMed1996

Differential expression of bcl-2 and bax in squamous cell carcinomas of the oral cavity.

The bcl-2 oncogene is a member of a family of genes encoding for proteins which regulate apoptosis (programmed cell death). Recent evidence suggests that the bcl-2 protein is regulated by a homologous protein bax which counteracts its effects and promotes apoptosis. Overexpression of bcl-2 has been reported in a number of human cancers, although correlations with tumour differentiation and clinical outcome are conflicting and depend on tumour type and site. We studied bcl-2 and bax protein expression in adjacent serial sections of 30 squamous cell carcinomas of the oral cavity and correlated this with tumour differentiation. Examination of normal epithelium showed bcl-2 expression confined to basal keratinocytes and dendritic cells. The bax immunostaining was seen throughout the thickness of the epithelium but was most intense in the suprabasal cells. Overall, moderate or marked immunostaining for bcl-2 was identified in 18/30 (60%) carcinomas and for bax in 19/30 (63%) tumours. The bcl-2 immunoreactivity was strongest in the poorly differentiated carcinomas where 6/7 (86%) showed strong staining. By contrast, bax immunoreactivity was strongest in the well-differentiated carcinomas with 8/11 (72%) staining strongly. In the well-differentiated tumour islands, there was inverse topographic distribution of bcl-2 and bax, with both proteins showing a pattern that recapitulated normal epithelium. Upregulation of bcl-2 protein was identified in dysplastic epithelium adjacent to invasive tumour and in many cases there was reduced bax immunostaining. These results suggest that alterations of bcl-2 and bax may play a role in the development of squamous cell carcinoma. Furthermore, disturbances of protein expression in dysplastic epithelium suggest a role in the early stages of epithelial carcinogenesis.

Adult↗