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Biomedical subjects

R Marks

Publications and source records attributed to R Marks.

At least 307 records · Page 17Linked to original sources
PubMed1987

Epidermal changes in human skin following irradiation with either UVB or UVA.

We have demonstrated previously that following UVB irradiation to normal volunteers there is an increase in epidermal and stratum corneum thickness and an increase in the thymidine autoradiographic labeling index. These changes are coupled with alterations in epidermal glucose-6-phosphate dehydrogenase and succinic dehydrogenase activities, despite the absence of erythema clinically. The use of a sunscreen did not completely prevent these changes. In this study, we have examined the effects of repeated irradiation of human skin with either UVB or UVA alone in order to compare the changes produced in the epidermis and to ascertain whether UVA irradiation could cause these. Irradiation with either UVB or UVA alone was found to increase the mean epidermal thickness, the mean stratum corneum thickness, and mean keratinocyte height significantly. Glucose-6-phosphate dehydrogenase activity was significantly increased throughout the epidermis, and succinic dehydrogenase activity was significantly decreased. The autoradiographic labeling index was significantly increased following UVB irradiation but not following UVA irradiation. These results demonstrate that UVA alone can have a direct effect on epidermal morphology and metabolism, suggesting that protection of skin from UV radiation should include adequate protection from UVA.

Adult↗
PubMed1987

Biochemical changes in desmosomes of bovine muzzle epidermis during differentiation.

Biochemical changes taking place in desmosomes during differentiation have been studied. Bovine muzzle epidermis was sliced horizontally into 6 layers, 0.2 mm thick, and desmosomes were isolated from each layer. These were then analyzed by polyacrylamide gel electrophoresis. The electrophoretic patterns of desmosomal proteins from the 6 layers were found to be qualitatively similar to each other, but there was an increase in the ratio of the amount of 150 kD glycoprotein (desmoglein I) relative to 240 and 210 kD proteins (desmoplakins) in the upper layers of the epidermis. This finding was supported by the similar increase observed in electrophoretic patterns of proteins extracted directly from each layer of the epidermis in electrophoretic sample buffer. In order to study the fate of desmosomal components in the stratum corneum, serial skin surface biopsies were stained with antisera against desmosomal components using indirect immunofluorescence techniques. This experiment showed that desmosomal proteins and glycoproteins persist in the stratum corneum but quantitatively decrease in the outer layers. This decrease may play a significant role in desquamation.

Animals↗
PubMed1987

Non-invasive instrumental techniques to detect terfenadine and temelastine induced suppression of histamine weals in man.

1. The effectiveness of chronic dosing with temelastine (SK&F 93944) 75 mg twice daily and terfenadine 60 mg twice daily compared with placebo in inhibiting the weal and flare response to intradermal histamine was assessed using non-invasive objective assessment techniques. 2. The mean weal thickness, as measured by the A-scan pulsed ultrasound device, was significantly decreased by both temelastine and terfenadine when compared with placebo. 3. There was a significant reduction in both the areas of the weal and the weal and flare, as measured by a digitizing tablet linked to a microcomputer, following treatment with temelastine and terfenadine compared with placebo and also between temelastine and terfenadine. 4. No significant difference was found in blood flow in the weal or flare as measured by the laser doppler flowmeter among any of the groups tested. 5. The ultrasound and digitizer techniques aid objectivity and precision in the investigation of the effects of drugs on histamine induced weals. 6. Temelastine and terfenadine were found to possess antihistaminic effects on histamine induced weal and flare in the skin.

Adolescent↗
PubMed1987

Cimetidine and chlorpheniramine in the treatment of chronic idiopathic urticaria: a multi-centre randomized double-blind study.

One hundred and twenty patients with chronic idiopathic urticaria, who entered a study at five centres (Sheffield, London, Bristol, Cardiff and Leeds) were treated with therapeutic doses of the H1 antagonist chlorpheniramine for 6 weeks. Histamine H1 non-responders (40 patients) were entered into a double-blind study and received chlorpheniramine plus cimetidine 400 mg q.d.s. (21 patients) or chlorpheniramine plus placebo (19 patients) for a further 8 weeks. The most important response measure was the change from baseline of the total symptom score: an assessment of the number and duration of new weals and degree of itching. There was a statistically significant difference between the average response in the two treatment groups in favour of chlorpheniramine plus cimetidine after 4 and 8 weeks' treatment (P less than 0.05 and P less than 0.01, respectively). No significant side-effects related to treatment were noted.

Chlorpheniramine↗
PubMed1987

Sebaceous gland hyperplasia and senile comedones: a prevalence study in elderly hospitalized patients.

Two hundred and eighty-six patients over the age of 65 (age range 65-102, mean age 82 years), who were hospitalized in geriatric wards, were examined clinically for the presence of sebaceous gland hyperplasia and senile comedones. The degree of solar elastotic change present was scored on a visual analogue scale. The prevalence rate of sebaceous gland hyperplasia and of senile comedones was found to be 26% in each case. Approximately one third of patients had both lesions. Neither of these lesions was related to either the degree of solar elastotic change or the skin type with regard to tanning ability. It was concluded that chronic solar exposure was not a likely cause of these common conditions.

Acne Vulgaris↗
PubMed1987

The effects of isotretinoin on follicular and sebaceous gland differentiation.

Follicular and sebaceous gland cell differentiation was investigated during treatment of acne patients with isotretinoin. Sebaceous glands were significantly reduced in volume and showed decreased metabolic activity as measured by glucose-6-phosphate dehydrogenase and succinic dehydrogenase enzyme activities. There was no measurable change in the volume of follicular duct epithelium or in its metabolic activity during treatment. Metabolic activity was also unchanged in the interfollicular epidermis, contrasting with the effects of another retinoid, etretinate. These findings provide no support for the proposition that alteration in the process of follicular keratinization forms a substantial part of the mode of action of isotretinoin.

Acne Vulgaris↗
PubMed1987

Epidermal dysplasia and skeletal deformity in congenital poikiloderma (Rothmund-Thomson syndrome).

Two sisters with congenital poikiloderma (Rothmund-Thomson syndrome) are described. One sister developed numerous keratotic lesions on the skin at an early age; these showed histological, ultrastructural and autoradiographic features of dysplastic change. The second sister had severe skeletal involvement in addition to the cutaneous poikiloderma, but no keratotic lesions. The clinical features of these cases demonstrate the variation in phenotypic expression of this disorder within a single family.

Bone Diseases↗
PubMed1987

Trimethoprim associated fixed drug eruption.

We report two cases of fixed drug eruption due to trimethoprim. Fixed drug eruption is a distinct entity characterized by the development of circular erythematous skin lesions which over a period of time become violaceous and leave an area of hyperpigmentation. Mucous membranes also may be affected. With re-administration of the drug the lesions recur in the same area but may extend to further new areas with each challenge.

Adult↗
PubMed1987

The effect of tetracycline and erythromycin in a model of acne-type inflammation.

The effects of systemically administered oxytetracycline and erythromycin in a guinea pig model of acne-type inflammation were assessed histologically and by tissue measurement techniques. It was found that oxytetracycline significantly reduced the volume and maximum area of inflammation compared with both control and erythromycin treated groups. Oxytetracycline also altered the morphology of the inflammatory infiltrate significantly reducing the proportion of polymorphonuclear leucocytes present. In this model, erythromycin did not alter the inflammatory response but did seem to reduce the amount of transepidermal elimination of inflammatory debris.

Acne Vulgaris↗
PubMed1987

Dysplastic epidermal change in immunosuppressed patients with renal transplants.

The prevalence of non-melanoma skin cancer has been studied in a group of 85 patients who have undergone renal transplantation. We also investigated the relationship between the development of neoplastic lesions and the duration of immunosuppression, previous sun exposure and infection with human papilloma virus. The overall prevalence of neoplastic and pre-neoplastic epidermal lesions in the group was 25 per cent, higher than that previously reported in studies from the United Kingdom. In patients who had survived for more than 80 months after transplantation the prevalence of these lesions was 38 per cent. There was no apparent relationship between sun exposure or skin type and the development of cutaneous neoplasia, despite the fact that the majority of lesions were found on sun-exposed sites. Exposure to ultraviolet radiation (UVR) is probably important as an initiator or co-factor rather than as a precipitant. In both sexes, high sun exposure was associated with the presence of viral warts. In females, there was a strong association between the presence of viral warts and the occurrence of neoplastic lesions elsewhere, giving support to the hypothesis that ultraviolet radiation may be acting as a co-factor in virally-mediated oncogenesis. Epidermal cell kinetic studies in 39 patients using in-vitro exposure to 3H thymidine and autoradiographic techniques showed no difference between the patients with neoplastic lesions and unaffected patients, and is not therefore a useful method of identifying an 'at risk' group.

Disease Susceptibility↗