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Biomedical subjects

R R Jones

Publications and source records attributed to R R Jones.

At least 73 records · Page 4Linked to original sources
PubMed1988

Lymphomatoid granulomatosis--evidence of a clonal T-cell origin and an association with lethal midline granuloma.

Lymphomatoid granulomatosis and lethal midline granuloma are both characterized histologically by atypical pleomorphic angiocentric infiltrates. Whether these conditions are malignant lymphoproliferative disorders remains controversial. Here we report the results of studies carried out in a patient with coeliac disease, who developed recurrent self-healing subcutaneous nodules with the histological changes of lymphomatoid granulomatosis and an invasive nasal tumour with the histological features of lethal midline granuloma. The patient subsequently also developed an erythrophagocytic syndrome. Immunocytochemical labelling of both cutaneous and nasal lesions demonstrated a predominant population of T cells with a CD4-negative CD8-positive phenotype. Analysis of DNA from cutaneous tissue revealed a discrete rearrangement of the beta and gamma T-cell receptor genes. These findings suggest that lymphomatoid granulomatosis is a clonal T-cell lymphoproliferative disorder and its association with lethal midline granuloma indicates that both conditions may have a common histogenesis.

Celiac Disease↗
PubMed1987

Release of neuronotrophic factor from rabbit corneal epithelium during wound healing and nerve regeneration.

Epithelial neuronotropic factor (ENF) is secreted by cultured epithelial cells of rabbit cornea and conjunctiva, and is active in promoting survival and inducing neurite outgrowth of cultured trigeminal neurons. This study evaluated the relation of ENF to corneal nerve regeneration utilizing a model of heptanol-induced epithelial wounding. The organ culture technique was used to collect ENF from the intact corneal epithelium, and a neuronal bioassay was utilized to quantify ENF. The results revealed no change in ENF secretion either during initial wound closure or after 1 week, when the epithelium had regenerated. However, ENF secretion was elevated 2.4 times in 2 weeks after wounding. Morphometric analysis of corneal nerves stained by gold chloride impregnation showed that the first sign of regeneration of intraepithelial nerves was observed after 2 weeks, and the normal pattern of epithelial neural density was re-established after 3 weeks. However, the neural density was still subnormal (35-47% less than the control) in the wounded epithelium up to 4 weeks after wounding. Thus it appears that a surge in ENF secretion occurred after epithelial regeneration but before nerve regeneration. The results suggest that ENF may mediate corneal nerve regeneration.

Animals↗
PubMed1987

Elastic fibres in normal and sun-damaged skin: an immunohistochemical study.

Sun-exposed and sun-protected skin obtained at post mortem from the nape of the neck in 14 subjects was immunostained using antisera to elastin, lysozyme, amyloid P component, and the plasma protease inhibitors alpha-I antitrypsin, alpha-I antichymotrypsin and alpha-2 macroglobulin. Both the normal elastic fibres in sun-protected skin, and elastosis in sun-exposed skin were positively immunostained for elastin, lysozyme and amyloid P component. Collagen fibres were unstained. No immunostaining of normal elastic fibres or elastosis in the skin was obtained with antisera to alpha-I antitrypsin, alpha-I antichymotrypsin or alpha-2 macroglobulin. It was concluded that the elastosis in sun-exposed skin does contain elastic fibres. The absence of immunostaining for plasma protease inhibitors probably indicates that the elastic material is mature, and not newly-formed.

Elastic Tissue↗
PubMed1986

The detection of endothelial cell antigens in cutaneous tissue using methacarn and periodate lysine paraformaldehyde fixation.

The use of monoclonal antibodies with endothelial cell specificity has prompted a search for methods of fixation which combine the morphology of paraffin-embedded tissue, with preservation of labile membrane antigens. Immunohistochemical staining using a variety of endothelial cell markers was compared in tissue fixed in formalin, methacarn, periodate lysine paraformaldehyde (PLP) and in frozen tissue. Whilst lectin-binding with Ulex europaeus agglutinin I (UEA) and localisation of Factor VIII-related antigen (FVIII RA) and laminin was well-visualised in methacarn-fixed and PLP-fixed tissue, fixation in PLP was necessary for the two monoclonal antibodies, PAL-E and EN4. PLP fixation has considerable potential for investigating the histogenesis of vascular tumours, particularly in Kaposi's sarcoma where frozen tissue represents a biological hazard. The normal staining pattern of human dermal vasculature is described in relation to the above endothelial cell antigens.

Acetates↗
PubMed1986

Nodular prurigo.

Explore the source record for details and available documents.

Eczema↗
PubMed1986

Histogenesis of Kaposi's sarcoma in patients with and without acquired immune deficiency syndrome (AIDS).

Immunohistochemical studies were performed in thirty skin biopsies from patients with Kaposi's sarcoma, who did and did not have the acquired immune deficiency syndrome (AIDS). Tumour histogenesis was rigorously tested using a battery of endothelial cell markers, which included two new monoclonal antibodies, EN4 and PAL E. These are both specific for endothelial cells and can be visualised in appropriately fixed paraffin embedded tissue. Whereas EN4 labels all endothelial cells, PAL E is negative in endothelium of lymphatic derivation. Lectin binding with Ulex europaeus agglutinin 1 (UEA-1) and the presence of factor VIII related antigen (FVIIIRA) and laminin were also examined. In nodular lesions of Kaposi's sarcoma the spindle cell areas were positive with EN4 and UEA-1, negative with PAL E, and showed focal staining for FVIIIRA and laminin. These results confirm that the tumour is of endothelial cell origin. Six patch stage lesions showed a network of angulated spaces, lined by cells that were positive with EN4 and UEA-1, negative with PAL E and anti-FVIIIRA, and showed only weak staining for laminin. This pattern was observed in both AIDS and non-AIDS related cases and strongly favours a lymphatic derivation for the tumour. This has important implications as it suggests that lymphatic endothelium may have special characteristics that lead to neoplastic transformation in patients with retrovirus infection.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Use of the interactive videodisc to teach pathology: a preliminary report.

Although use of computers in education dates to the early 1960s,1-3 it is only with the arrival of the "microcomputer revolution" that computers have become economically feasible in medical education. The advent of inexpensive and relatively powerful microcomputers initiated something of a chain reaction; microcomputers became available for educational purposes, thus creating a market for educational software. This accelerated development of educational software in turn made microcomputers more useable. While synergistic hardware and software development has occurred repeatedly in the microcomputer industry, it is only in the beginning stages in medical education. This paper presents a discussion of the development of one computer-assisted instructional program that utilizes an interactive videodisc format.

Computer-Assisted Instruction↗
PubMed1985

Monoclonal antibodies specific for subsets of epidermal keratins: biochemical and immunocytochemical characterization--applications in pathology and cell culture.

Keratin composition has been widely used as a biochemical marker of differentiation in normal epithelia, cell culture systems and tumours of epithelial tissues. We have been developing a model system for the study of human squamous epithelial cell differentiation, and among a panel of monoclonal antibodies we have generated for analysing this system are two antibodies recognizing subsets of epidermal keratins. The two antibodies, designated LICR-LON-16a and LICR-LON-29b, were raised to the human squamous carcinoma cell line LICR-LON-HN-5, and we describe here their biochemical and immunocytochemical characterization. Antibody 16a reacts with only epidermal basal cells in normal human skin and shows specificity for the 45 and 46 kdalton keratins. Antibody 29b stains all living layers of the epidermis, and reacts with a broad range of ketain polypeptides, (45-56 kdaltons) in immunoblotting analyses. We have investigated the alterations of cellular staining that occur in chronic hyperproliferative skin diseases and carcinomas and compared this with the staining of multilayered cultures of normal keratinocytes and the HN-5 cell line. We show that in squamous cell carcinomas and in HN-5 cell xenografts 16a and 29b stain only the well-differentiated cell types. Furthermore we found that the basal cell specificity of 16a was lost in all of the hyperproliferative skin lesions examined including psoriasis and eczema. This transition to suprabasal staining pattern was also seen in the cultures of normal keratinocytes and HN-5 cells. We conclude that aberrant keratin synthesis or abnormal post-translational processing of keratins associated with an increased rate of cell turnover could account for the altered expression of the epitope recognized by antibody 16a.

Antibodies, Monoclonal↗
PubMed1985

Femoral mycotic aneurysm presenting as arthritis and purpura.

A case is described with recurrent arthritis and skin rash confined to the right lower limb and exacerbated on each occasion by exercise. Investigation established this to be due to a mycotic aneurysm of the right common femoral artery. Treatment with excision and grafting and antibiotics resulted in full recovery. Mycotic aneurysm and the unusual presenting features in this case are discussed.

Aneurysm, Infected↗
PubMed1985

O'Brien's actinic granuloma.

The nosological position of actinic granuloma of O'Brien remains controversial. In this report a typical case is described and the features which distinguish the condition from other closely related granulomatous disorders are discussed. Histological changes are of some value in distinguishing actinic granuloma from atypical facial necrobiosis, granuloma multiforme and granuloma annulare arising in elastotic sites. Final diagnosis, however, is usually based upon the clinical features. Our case showed a successful therapeutic response to intralesional steroid.

Diagnosis, Differential↗
PubMed1985

Juvenile plantar dermatosis. A clinicopathologic study.

Fifty-six patients had juvenile plantar dermatosis (JPD). The plantar surface of the toes and the anterior third of the sole were the sites most commonly affected. Less commonly affected were the dorsal surface of the toes and the fingertips. No seasonal variation was found, and treatment was generally ineffective. Preventative measures had no influence on the course of the condition. Histopathologic features included psoriasiform acanthosis, with focal loss of granular cell layer, and uniform parakeratosis. Distinctive features included a tendency for the dermal infiltrate to localize around sweat ducts at their point of entry into the epidermis. In addition, inflammatory changes within the epidermis were localized mainly to the acrosyringium and included paranuclear vacuolization of epidermal keratinocytes, spongiosis, and slight spongiotic vesiculation. These changes are similar to those described in other eczematous conditions, and there is little evidence to suggest that disordered sweating plays a primary role in the pathogenesis of JPD.

Adolescent↗