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Biomedical subjects

J McLelland

Publications and source records attributed to J McLelland.

At least 19 recordsLinked to original sources
PubMed1992

Topical ketoconazole does not potentiate oral cyclosporin A in allergic contact dermatitis.

Cyclosporin A is an effective drug but its use is limited by its side effects. Since oral ketoconazole inhibits the metabolism of oral cyclosporin, we set out to find out whether topical ketoconazole would enhance the effect in the skin of oral cyclosporin. Five patients with contact allergic dermatitis (CAD) were given a 6-day course of cyclosporin (1 mg/kg/day) and applied 2% ketoconazole cream to an area on one arm and the inert base to the other. Serial dilutions of the relevant allergen were applied to the arms at 3 days for 48 hours, and the responses were measured objectively a day later. There was no significant difference between responses at the two sites, indicating that topical ketoconazole does not enable the dose of oral cyclosporin to be reduced in CAD.

Administration, Cutaneous↗
PubMed1991

Oral cyclosporin inhibits the expression of contact hypersensitivity in man.

The expression of delayed contact hypersensitivity was studied in 6 patients with chronic contact dermatitis treated with cyclosporin A (CsA) 5 mg/Kg/day. Quantitative patch test challenge was used to establish individual dose-response curves and threshold concentration to certain allergens in the European Standard Battery. In all 6 patients, responses were reduced over the whole range of allergen concentrations, and in the 5 in whom the threshold for expression of contact hypersensitivity could be determined, the threshold was raised by CsA therapy. In addition, the clinical manifestations of allergic contact dermatitis underwent complete resolution within 2-3 weeks of CsA therapy. It was concluded that CsA inhibits expression of delayed contact hypersensitivity reactions in human skin.

Administration, Oral↗
PubMed1991

Measurement of cutaneous inflammatory reactions using a scanning laser-Doppler velocimeter.

The performance of a new scanning laser-Doppler velocimeter (LDV), which can rapidly measure blood flux over a large area of skin without contact with the skin surface, was compared with that of a conventional laser-Doppler instrument. The vascular response was measured to a range of doses of UVB, and dilutions of contact allergens and sodium lauryl sulphate. The detection threshold of the scanning LDV was equal to, or lower than, that of the conventional instrument. For allergic contact hypersensitivity reactions (ACH), the coefficient of variation was significantly less using the scanning LDV. The scanning LDV allowed accurate measurement of the change in area that occurs with increasing intensity of inflammatory reaction. For ACH reactions the area of inflammation continued to increase at dilutions where blood flux had reached a plateau. The flare area was found to increase linearly with log dose of histamine with no change in blood flux.

Dermatitis↗
PubMed1991

Seasonally recurrent granuloma annulare of the elbows.

Granuloma annulare may be recurrent and various precipitating factors have been described but seasonal cases have not been previously reported. We describe two patients with granuloma annulare on the elbows which developed in spring and resolved spontaneously in October each year. We believe that this type of seasonally recurrent granuloma annulae has not been previously described.

Adult↗
PubMed1991

'Irritants' increase the response to an allergen in allergic contact dermatitis.

We studied the effect of "irritants" on the response to an allergen in 15 patients. Dilutions of allergens were applied in duplicate, and 24 hours later they were removed and sodium lauryl sulfate (11 subjects) or anthralin (dithranol) (four subjects) was applied for a further 24 hours to one set of patches. Control dilutions of irritants alone were applied. Responses were measured objectively at 72 hours. The response to both allergen and irritant was greater than to either alone. Doses of allergen, which did not produce a response when applied alone, produced a response when an irritant was added. Irritants therefore increase the allergic contact dermatitis response and may explain the presence of contact dermatitis in patients with negative patch tests.

Allergens↗
PubMed1990

Contact dermatitis with negative patch tests: the additive effect of allergens in combination.

We deduced on theoretical grounds that conventional patch testing would be inadequate for the detection of sensitivity to multiple allergens. Fourteen patients with positive patch tests to two unrelated allergens were studied and the response to those two allergens was measured when tested singly or in combination, using 10 different pair combinations from 15 common allergens. With serial dilutions in chloroform (14 patients) and paraffin (four patients), the response was related to the log-dose of the allergen, and change in skin-fold thickness corresponded well with clinical grading. Single allergens diluted below the threshold for a patch-test response gave a response when given in combination, the threshold for a response to one allergen being lowered by the presence of another. On the linear part of the dose-response curves the response to the mixture of allergens was additive, the combined response being the sum of the individual components. Approaching the plateau region the response to the combination was greater than to the individual allergens but less than the sum of the single responses. The same results were obtained with allergens in paraffin. We conclude that conventional single allergen patch testing by itself is inadequate for the diagnosis of contact dermatitis.

Allergens↗
PubMed1990

Langerhans cell histiocytosis: the case for conservative treatment.

Fifty eight children with Langerhans cell histiocytosis who were referred to this hospital between 1980 and 1987 were studied. Fourteen had single system disease, and 44 had multisystem disease, of whom 22 had vital organ dysfunction. A conservative approach to treatment was adopted, and when systemic treatment was indicated a short course of prednisolone was used first. Eight of the patients with single system disease required no treatment, while six received local treatment alone. Eight of the patients with multisystem disease did not require systemic treatment, 17 were given prednisolone alone, and 19 were given cytotoxic drugs. Of the 14 with single system disease 13 had no long term after effects. Eight of the patients with multisystem disease died, 24 had long term after effects, and 12 had none. Outcome was related to age and Lahey score. These results compare favourably with other series in which more aggressive approaches were used, and support our conservative approach to treatment.

Adolescent↗
PubMed1989

Anatomy of the avian cecum.

The gross anatomy of the avian ceca is reviewed. In most birds, right and left ceca arise laterally or ventrolaterally at the junction of the small and large intestines. In a few species, the ceca open into the rectum ventrally or dorsally. In many herons and bitterns, only one cecum is present, and in the secretary bird there are two pairs of ceca. Ceca are absent in woodpeckers, hummingbirds, swifts, kingfishers, pigeons, mousebirds, cuckoos, and parrots. Ceca may be classified according to length into long, moderately or poorly developed, and vestigial types. In most birds, the ceca are simple tubular structures with minor variations in shape. However, in a few species, including the ostrich, rheas, kiwis, some tinamous, the red-throated loon, screamers, the satyr tragopan, the great bustard, and the pin-tailed sandgrouse, the ceca are sacculated or have diverticula. There is usually no correlation between the development of the ceca and systematic position. Except in grouse (Tetraonidae), in which the long ceca are related to the fibre content of the diet, the correlation between cecal development and diet is extremely limited. There is no relationship between the size of the ceca and the length and width of the rectum.

Animals↗
PubMed1989

A flow cytometric study of Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH), or histiocytosis X, is now generally considered to be a non-malignant condition. A flow cytometric (FCM) study of a single case has, however, been published which claimed to provide evidence to contradict this. The presence of DNA-ploidy as detected using this technique is a feature of malignant and pre-malignant disease. In this reported single case, DNA-ploidy was present but the clinical features of this patient were atypical for LCH. We have performed a FCM study of the DNA of nine biopsies of LCH lesions from six patients with well-established disease. In addition, in one of these, fresh tissue studies including the use of an anti-CD I monoclonal antibody to specifically label the LCH cells were performed. In all cases the DNA content of the cells was entirely normal. We therefore found no evidence that LCH is a neoplastic disorder.

Adult↗
PubMed1988

The incidence of immunosuppression-related skin disease in long-term transplant patients.

One hundred and twenty-one patients who had received a renal allograft between 4 months and 21 years previously (mean +/- SD, 71 +/- 62 months) were studied. Seventy-two patients were conventionally immunosuppressed with azathioprine and prednisolone, and 36 had been exposed to the current regime of cyclosporine, azathioprine, and prednisolone. Forty-five patients had viral warts, of whom 20 had more than 10 warts. The presence of viral warts was significantly associated with pale skin type, excess sun exposure, and with duration of allograft. Viral warts were significantly more common in those on conventional immunosuppressive therapy, but this could be solely a reflection of the difference in duration of transplant between the 2 groups. Twelve patients were found to have developed dysplastic or neoplastic skin lesions since transplantation. The incidence of dysplasia increased with increasing age and was significantly associated with pale skin type, excess sun exposure, and duration of allograft. Despite the shorter duration of treatment in those on the new treatment regime, there was no difference between the 2 groups in the proportion of patients with dysplastic skin lesions. Immunosuppression-related skin disease may be a significant problem in allograft recipients in this country, and we suspect that patients taking cyclosporine will have similar problems to those on conventional immunosuppressive drugs alone. Immunosuppressed patients should be advised to avoid sun exposure, to use sunscreens, and should be monitored carefully for the development of dysplastic lesions.

Dermatomycoses↗