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Biomedical subjects

J Ashworth

Publications and source records attributed to J Ashworth.

At least 37 records · Page 2Linked to original sources
PubMed1990

Air quality in the vicinity of urban roads.

Motor vehicle emissions are a major source of CO, NOx and lead particulate concentrations to urban air quality. London urban Boroughs with high traffic densities are therefore a particular cause for concern. The air quality was monitored at an urban background site in the London Borough of Haringey for 2-years. The results of this study are assessed and their effect on human health is considered in the light of EC Directives and WHO guidelines. A desk top modelling technique based on Gaussian diffusion theory was used to predict the CO levels found at the background site. All predicted levels had a accuracy of better than 30%.

Air Pollution↗
PubMed1990

FACE--facial Afro-Caribbean childhood eruption.

Five cases of a distinctive facial eruption in Afro-Caribbean children are described. Distinctive features include monomorphic papules that are confined to the face, especially around the mouth, eyelids and ears, its greater prevalence in black children, and its tendency to persist for several months before spontaneous resolution. The aetiology of this condition is unknown and its importance lies in reassuring patients of the benign and purely cutaneous nature of the eruption.

Child↗
PubMed1990

Multiple eruptive histiocytoma cutis in an atopic.

A case of generalized histiocytoma cutis occurring in an atopic and mimicking widespread molluscum contagiosum is described. Immunochemical staining showed that the lesions were positive for factor XIIIa.

Adult↗
PubMed1989

Serum amyloid P component binds to cell nuclei in vitro and to in vivo deposits of extracellular chromatin in systemic lupus erythematosus.

Serum amyloid P component (SAP) is the single plasma protein that, from the milieu of whole normal human serum, undergoes specific calcium-dependent binding to isolated DNA and chromatin in vitro. We now report for the first time that SAP in whole serum also undergoes calcium-dependent binding to nuclei of epidermal cells in sections of normal human skin and to nuclei of fixed Hep-2 cells, a human epithelial cell line. Furthermore, and most importantly, SAP was detected in association with unusual globular dermal deposits of nuclear material in skin biopsies from two patients with systemic lupus erythematosus. This is the first evidence for binding of SAP to extracellular chromatin in vivo and supports the idea that SAP may have an important physiological role in the disposal of this material.

Cell Line↗
PubMed1989

Flow cytometrically-sorted residual HLA-DR+T6+ Langerhans cells in topical steroid-treated human skin express normal amounts of HLA-DR and CD1a/T6 antigens and exhibit normal alloantigen-presenting capacity.

Topical corticosteroids decrease the number of HLA-DR+T6+ Langerhans cells (LCs) and the antigen-presenting capacity of epidermal cells (ECs). We have investigated the properties of residual HLA-DR+T6+ LCs in steroid-treated human skin. Flow cytometric analysis revealed that clobetasol propionate 0.05% applied twice daily for 7 d reduced the percentage of HLA-DR+T6+ LCs in EC suspensions to 46% of control (from a mean percentage +/- sem of 2.49 +/- 0.30 in control skin to 1.15 +/- 0.22 in steroid-treated skin), but did not significantly alter the relative amounts of HLA-DR and CD1a/T6 antigens per individual HLA-DR+T6+ cell. HLA-DR+T6- and HLA-DR-T6+ cells were not detected in either group. Steroid therapy significantly decreased the allostimulatory capacity of unsorted ECs. By contrast, in parallel experiments in which the same EC suspensions were greatly enriched (85% to 90%) for HLA-DR+T6+ LCs by flow cytometric sorting, the allostimulatory capacity of purified LCs from steroid-treated skin was not significantly different from control. Residual HLA-DR+T6+ LCs, which preserve their antigenic markers and alloantigen-presenting function, may be relatively unaffected because they have only recently immigrated into the epidermis, or they may represent a subgroup of steroid-resistant LCs. Alternatively, given the dose response relationship between topical steroid potency and decrease in HLA-DR+T6+ LC numbers, the apparent steroid resistance of residual HLA-DR+T6+ LCs may reflect heterogenity in the density of expression of LC steroid receptors.

Administration, Topical↗
PubMed1989

Brawny cutaneous induration and granulomatous panniculitis in large cell non-Hodgkin's (T suppressor/cytotoxic cell) lymphoma.

A 56-year-old lady presented with striking peau d'orange-like, woody, diffuse infiltration of the skin of the upper, inner aspects of both arms and thighs. Initial biopsy specimens showed a granulomatous panniculitis with non-specific lymphohistiocytic infiltration. Clinical deterioration occurred with development of ascites and peripheral oedema; a single axillary node became palpable. Cytology of ascitic fluid, and histology and immunopathology of the axillary node, and of a further skin biopsy, now revealed diagnostic changes of a diffuse large cell lymphocytic lymphoma of T suppressor/cytotoxic type. Granulomatous panniculitis resulting in diffuse cutaneous infiltration may rarely be a presenting sign of malignant lymphoma.

Arm↗
PubMed1989

Flow cytometric analysis and sorting of HLA-DR+CD1+ Langerhans cells.

There is a considerable need for reliable methods for enumeration and enrichment of Langerhans cells (LCs), since they continue to be the subject of intensive investigation in normal and diseased skin. It has been claimed that standard labelling with either anti-HLA-DR or OKT6 antibodies alone may fail to identify potentially important subsets of LCs with the phenotypes HLA-DR+CD1- and HLA-DR-CD1+. We report here on flow cytometric analysis of suction blister-derived normal epidermal cell (EC) suspensions, double stained with phycoerythrin-conjugated anti-HLA-DR and fluoresceinated OKT6. In seven separate experiments, no evidence for the existence of either HLA-DR+CDI- or HLA-DR-CDI+ ECs was obtained. We found that HLA-DR+CDI+LCs, which constituted a mean of 2.5% (+/- 0.3 SEM) of all ECs, could be readily identified on the basis of fluorescence, and that their light scatter characteristics were those of moderately sized cells of low granularity. We further describe our method for flow cytometric enrichment of such HLA-DR+CDi+ LCs for functional studies, based on selection on both fluorescence and light scatter criteria. Enrichment is to greater than 90% purity, and the method is applicable to the small number of ECs (approximately 1 x 10(6] obtained from a suction blister.

Antigens, CD1↗
PubMed1989

PUVA therapy decreases HLA-DR+ CDIa+ Langerhans cells and epidermal cell antigen-presenting capacity in human skin, but flow cytometrically-sorted residual HLA-DR+ CDIa+ Langerhans cells exhibit normal alloantigen-presenting function.

We have investigated the effects of PUVA therapy on human Langerhans cell (LC) immunophenotype and function. Epidermal sheets were obtained from exposed, and control shielded, forearm skin at the end of a course of PUVA therapy, in patients receiving treatment routinely for a variety of dermatoses. PUVA therapy decreased the overall number of HLA-DR+CDIa+ LCs in epidermal sheets, and in epidermal cell (EC) suspensions examined using a fluorescence activated cell sorter (FACS). PUVA therapy also reduced the overall EC allostimulatory capacity in the allogeneic epidermal cell-lymphocyte reaction (ELR), and the capacity of ECs to present tetanus toxoid to, and augment concanavalin A-mediated stimulation of, lymphocytes in the autologous ELR. Depressed allostimulation by ECs from PUVA-treated skin could not be restored by indomethacin (added to block prostaglandin synthesis). The reductions in LC numbers and EC allostimulatory capacity varied according to dose, and time since cessation, of PUVA therapy, and in individual patients were of comparable degree. By contrast, the allostimulatory capacity of residual LCs from PUVA-treated skin (purified using the FACS) did not differ from that of purified control LCs. PUVA-induced suppression of cutaneous immune responses, therefore, results at least in part from an overall impairment of EC antigen-presenting capacity. Residual HLA-DR+CDIa+ LCs in PUVA-treated skin which retain their alloantigen-presenting function may represent a subgroup of PUVA-resistant LCs; alternatively, these cells may be as yet unaffected because they have only recently migrated into the epidermis.

Antigen-Presenting Cells↗
PubMed1989

Allergic and irritant contact dermatitis compared in the treatment of alopecia totalis and universalis. A comparison of the value of topical diphencyprone and tretinoin gel.

Diphencyprone is a potent topical sensitizer, but is non-mutagenic in the Ames test (unlike dinitroclorobenzene) and remains relatively stable in solution (unlike squaric acid dibutyl ester). Seventeen patients with total loss of scalp hair (eight alopecia totalis, nine alopecia universalis) were treated by maintaining on one side of the scalp an allergic contact dermatitis induced by 2,3 diphenylcyclopropenone-I ('diphencyprone'), and on the other side an irritant contact dermatitis using tretinoin gel (Retin A). After 20 weeks, treatment with tretinoin was stopped and diphencyprone was applied bilaterally for a further 10 weeks. Satisfactory regrowth of terminal hair on the scalp was achieved in only one patient. Eyebrow, eyelash and beard regrowth was achieved in one individual whilst in another, moderate, but not cosmetically satisfactory, scalp regrowth took place. In no patient did regrowth take place at tretinoin treated sites until after diphencyprone was substituted.

Administration, Topical↗
PubMed1989

Sarcoidosis presenting with multiple delled atrophic facial lesions.

We describe a patient who presented with multiple atrophic, delled erythematous facial lesions with surface scaling. Skin biopsy revealed a granulomatous histology, and a Kveim test was positive. Similar cutaneous lesions have not been previously reported in sarcoidosis.

Aged↗
PubMed1989

Potency classification of topical corticosteroids: modern perspectives.

The effects of topical corticosteroid therapy upon human epidermal Langerhans cell surface markers were studied. The reduction in numbers of human leukocyte antigen-DR+/T6+ Langerhands cells proved to be a potency-related effect and Langerhans cell enumeration may therefore have some use as an adjunct in the assessment of steroid potency. Further studies showed that corticosteroid therapy also reduced the function of Langerhans cells in terms of epidermal cell alloantigen-presenting capacity. However, experimental variation and the high antigen-presenting potency of residual flow cytomterically sorted human leukocyte antigen-DR+/T6+ Langerhans cells following steroid application (1) mean that such functional assessments of epidermal cell alloantigen-presenting capacity cannot be recommended as an easily reproducible method for measuring steroid potency.

Administration, Topical↗