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Biomedical subjects

A J Bircher

Publications and source records attributed to A J Bircher.

82 records · Page 5Linked to original sources

Blood flow response to cryosurgery on basal cell carcinomas.

Cryosurgery with liquid nitrogen is commonly used to treat benign and malignant skin tumours. One of the crucial factors which influences the freezing and thawing rate of the target cells is the response of the microcirculation to cold stimulus. In our experiment, laser Doppler flowmetry was used to monitor blood flow during cryosurgical treatment of basal cell carcinomas. Outside the frozen tissue hemisphere, blood flow, as measured by laser Doppler flowmetry, increased almost instantaneously and remained on a high level during thawing. Baseline blood flow at the contralateral anatomical site remained stable. Pharmacological or physical modification of the cutaneous microcirculation before therapy may influence freezing and thawing times, and therefore the outcome with regard to healing, cosmetic appearance and the recurrence rate of basal cell carcinomas.

Aged↗

Eczematous infiltrated plaques to subcutaneous heparin: a type IV allergic reaction.

Two patients are described who had delayed reactions with eczematous plaques to subcutaneous injections of heparin. Subcutaneous challenge with high and low molecular weight heparin compounds were positive in both patients. Patch and intradermal tests with heparin were positive in one subject. Histological and immunohistochemical studies indicated that it was a type IV allergic reaction.

Drug Eruptions↗

Pharmacodynamic measurements of methyl nicotinate percutaneous absorption: the effect of aging on microcirculation.

The penetration of drugs through aged skin is important both in terms of transdermal delivery to elicit systemic pharmacological effects, and for topical treatment. Cutaneous microcirculation efficiency, an integral parameter in the overall process of percutaneous absorption, was studied in young (20-34 years) and old (64-86 years) individuals. Cutaneous erythema as induced by topical administration of methyl nicotinate to the ventral forearm, was monitored non-invasively using laser-Doppler flowmetry. Dose-response behaviour was characterized by five parameters: (i) the time of onset of action; (ii) the time to reach maximum response; (iii) the magnitude of the maximum response; (iv) the area under the response-time curve; and (v) the time to decay to 75% of the maximum response. Additionally, the sensitivity and efficiency of the cutaneous microcirculation in both age groups was evaluated using a pharmacokinetic-pharmacodynamic model. Statistical analysis of all data showed no significant differences between the age groups for the same concentrations. The results indicate that microvessel reactivity to the applied stimulus is comparable in the ventral forearm of both young and old populations.

Adult↗

Water-induced itching.

In this paper the current knowledge on water-induced pruritus is reviewed. To the present, three forms, namely aquagenic pruritus (AP), aquagenic pruritus of the elderly (APE) and water-related itching in polycythemia rubra vera (PRV), have been recognized. Despite clinical similarities it appears that the pathophysiology is different in the three forms. The currently most effective treatment for AP is addition of sodium bicarbonate to the water, control of xerosis with emollients for APE and aspirin for water-induced itching in PRV.

Aged↗

Aquagenic pruritus. Water-induced activation of acetylcholinesterase.

Four patients with aquagenic pruritus (AP), one patient with polycythemia rubra vera, one patient with cold urticaria, and three normal control volunteers were studied to better understand the pathophysiology of water-induced itching. Punch biopsy specimens were taken before and after water contact; the specimens were immediately frozen, sectioned, and stained histochemically for acetylcholinesterase (AChE) activity. This was localized in the nerve fibers surrounding eccrine sweat glands and was quantified by microspectrophotometry. In AP and polycythemia rubra vera after water exposure a significantly increased AChE activity suggesting acetylcholine release was observed, whereas in the patient with cold urticaria and the controls, a significant decrease was noted. Two related patients with AP had an inherited abnormality of serum cholinesterase, which, however, had no obvious correlation with their particular disease. The proof of AChE activation might support the clinical diagnosis and indicate a hypothetical involvement of eccrine sweat glands in the pathogenesis of AP.

Acetylcholinesterase↗

Baboon syndrome resulting from systemic drugs: is there strife between SDRIFE and allergic contact dermatitis syndrome?

The term 'baboon syndrome' (BS) was introduced 20 years ago to classify patients in whom a specific skin eruption resembling the red gluteal area of baboons occurred after systemic exposure to contact allergens. Thereafter, similar eruptions have been reported after systemic exposure to beta-lactam antibiotics and other drugs. In addition to the presentation of 2 of our own cases, we have reviewed and characterized the main clinical and histological aspects of published reports of drug-related baboon syndrome (DRBS) and compared the primary clinical signs from such cases to those found in other distinct drug eruptions. Of approximately 100 published baboon syndrome cases, 50 were identified as drug-induced. Of these, 8 were representatives of systemically induced contact dermatitis (SCD), and 42 were examples of drug eruptions elicited by systemic administration of either oral or intravenous drugs. The main clinical findings included a sharply defined symmetrical erythema of the gluteal area and in the flexural or intertriginous folds without any systemic symptoms and signs. 14 of 42 cases were elicited by amoxicillin, 30 of the 42 patients were male, and latency periods were between a few hours and a few days after exposure. DRBS is a rare, prognostically benign and often underdiagnosed drug eruption with distinct clinical features. The term baboon syndrome, however, does not reflect the complete range of symptoms and signs and is ethically and culturally problematic. Moreover, baboon syndrome is historically often equated with a mercury-induced exanthem in patients with previous contact sensitization. Symmetrical drug-related intertriginous and flexural exanthema, or SDRIFE, specifically refers to the distinctive clinical pattern of this drug eruption, and the following diagnostic criteria are proposed: 1) exposure to a systemically administered drug either at the first or repeated dose (excluding contact allergens); 2) sharply demarcated erythema of the gluteal/perianal area and/or V-shaped erythema of the inguinal/perigenital area; 3) involvement of at least one other intertriginous/flexural localization; 4) symmetry of affected areas; and 5) absence of systemic symptoms and signs.

Adult↗

Allergic contact dermatitis from tixocortol pivalate in a nasal spray masquerading as infectious complication of sinusitis.

Allergic contact dermatitis to corticosteroids is not uncommon and is increasingly reported. Contact allergy to nasal corticosteroids is rare and may present with atypical symptoms, which may be confused with infectious complications. We report on a patient in whom the misinterpretation of her allergic nasal symptoms to the corticosteroid tixocortol pivalate resulted in hospitalization and considerable medical expenses.

Adult↗