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Biomedical subjects

R Marks

Publications and source records attributed to R Marks.

At least 487 records · Page 27Linked to original sources
PubMed1977

The effects of anti-prostaglandin agents on epidermal proliferation induced by dermal inflammation.

Experimentally induced dermal inflammatory lesions cause epidermal hyperplasia and increased thymidine autoradiographic indices in the overlying epidermis. In the experiments described here anti-prostaglandin agents (indomethacin, aspirin, prednisolone and polyphloretin phosphate) were given to guinea-pigs with experimentally induced dermal granulomata in an effort to learn more about the dermal control of epidermal proliferation. Indomethacin caused a significant reduction in the epidermal hyperplasia and labelling index in the epidermis overlying carageenan granulomata. Similar but less marked reductions in epidermal proliferation were seen with the other agents used. Some reduction, which proved not to be statistically significant, was also seen in the epidermal proliferation due to kaolin granulomata. Slight reduction in epidermal hyperplasia, but no effect on thymidine incorporation, was seen in proliferation induced by tape stripping.

Animals↗
PubMed1977

Epidermal abnormalities in Refsum's disease.

A female patient with severe Refsum's disease is described. She had striking ichthyosis and detailed investigations into the structure of the epidermis were performed. Light microscopy and transmission electron microscopy revealed lipid-containing vacuoles in the epidermis. Scanning electron microscopy of the stratum corneum showed disruption and the presence of microvilli on individual horn cells consistent with a high output state of epidermal cell production.

Adult↗
PubMed1977

The wages of warmth: changes in erythema ab igne.

Biopsies from 20 patients with erythema ab igne (EAI) were examined and compared with biopsies from the legs of 7 elderly control subjects. Epidermal thinning and flattening of the dermo-epidermal junction were seen in most of the tissues examined but were more prominent in the EAI biopsies. Basal cell degenerative change with vacuolation was frequently observed in the EAI specimens. Epidermal atypia amounting to preneoplastic change was observed in 4 EAI biopsies. The dermis was thinned and showed (a) marked oedema and connective tissue disruption and (b) accumulation of elastic staining material. Both haemosiderin and melanin were found within the dermis. The small blood vessels showed a striking abnormality in 7 patients and 2 control biopsies in that the endothelial cells were enlarged and the nuclei were hyperchromatic and irregular in size and shape. This change may be due more to stasis than to chronic heating.

Aged↗
PubMed1977

Evolution of the lesion of discoid lupus erythematosus: a comparison with lichen planus.

The tissue processes leading to the development of the epidermal changes in the lesion of discoid lupus erythematosus have been studied. Typical lesions in fifteen patients have been examined using cell kinetic and immunofluorescence techniques. The results suggest that a very active repair mechanism is operative within the epidermis with heightened epidermopoiesis and epidermal cell migration. The findings have been contrasted with those of previous similar studies of lichen planus. It is suggested that a major difference between the gross and microscopic appearance in the two diseases may be partially on the basis of differing patterns of immunoprotein deposition.

Adult↗
PubMed1977

Acquired ichthyosis: multiple causes for an acquired generalized distrubance in desquamation.

Four patients with acquired ichthyosis are described and the results of histological, histometric, autoradiographic and enzyme histochemical studies reported. Three of the patients were found to have in addition the following underlying diseases--malnutrition, reticulum cell sarcoma and panhypopituitarism. The fourth patient did not have any systemic disorder and the provoking cause of his ichthyotic condition remains obscure. Clinically these patients demonstrated the skin changes of autosomal dominant ichthyosis although their condition tended to fluctuate in severity. The various studies performed indicated that the histological and metabolic changes tended to reflect the clinical state of the patients and that these parameters did not differ significantly from those observed in atuosomal dominant ichthyosis.

Adolescent↗
PubMed1977

Skin stretching and epidermopoiesis.

In order to determine whether the heightened epidermopoiesis seen over dermal expansile lesions is due to stretch, attempts were made to induce similar degrees of skin stretching by implanting Silastic materials in the dermis of guinea-pigs. Silastic elastomer produced mild inflammation and thus, this model could not be used to evaluate the effects of stretch alone. Silastic testicular implants caused no inflammation and were found to initially stimulate a rise in thymidine autoradiographic labelling index, but no increase in epidermal thickness during the experiment. It is suggested that there is an increase in the germinative pool size caused by stretch but that the epidermal hyperplasia seen over dermal lesions is due to some other process.

Animals↗
PubMed1976

Measurement of dermal thickness with the Harpenden skinfold caliper.

A simple method of determining skin thickness using the Harpenden Skinfold Caliper is described. Using this technique the atrophy caused by the topical application of Fluocinolone acetonide in normal volunteers has been detected. As a comparison the skin thickness was also measured in the same individuals by an established x-ray technique. Not only was a similar degree of atrophy observed but also a high degree of correlation (r=0.82, n=32, P less than 0.001) was found between the values obtained with both techniques.

Atrophy↗
PubMed1976

Epidermal architecture, growth, and metabolism in acromegaly.

Epidermal architecture, replication, and anabolic activity were studied in six patients with acromegaly. Patients with acromegaly had significant larger viable epidermal cells than controls. The rates of incorporation of tritiated thymidine, proline, and histidine into skin slices in vitro was also significantly increased in acromegalic patients. The mean autoradiographic labelling indices after intracutaneous injection of triated thymidine were 8.4% in the acromegalic patients and 5.1% in the control group. None of the changes observed could be closely correlated with levels of serum growth hormone.

Acromegaly↗
PubMed1976

Further studies on section thickness measurement.

A rapid, simple, accurate and reproducible technique for measuring section thickness using an instrument known as a surfometer is described. It has shown that microtome settings cannot be relied upon as a means of monitoring the thickness of sections of quenched or wax-embedded tissue. However, there appeared to be a linear relationship between microtome setting and the thickness of dewaxed sections. Microtome settings seem to provide an accurate indication of the thickness of araldite sections.

Animals↗
PubMed1976

Studies on the effect of salicylic acid on normal skin.

This investigation was prompted by our ignorance of the way in which salicyclic acid aids desquamation. Salicyclic acid in aqueous cream or white soft paraffin and in concentrations of 2-12% was applied to normal skin of twenty-three subjects while the vehicle alone was applied to the contralateral sites. Biopsies and skin surface biopsies were taken from the test and control sites after 1 week. Histological examination showed that there was less horny layer on the test specimens but that there were no qualitative or quantitative differences in the structure of the viable epidermis. Portions of the biopsies were incubated in the presence of tritiated precursor compounds and subsequent autoradiographic examination showed no difference in the incorporation of thymidine, cytidine or histidine between test and control preparations. Scanning electron microscopy of skin surface biopsies showed some changes in all specimens--presumably due to hydration--but also showed striking differences between test and control sites and were especially marked with higher concentrations of salicylic acid. It is suggested that salicylic acid causes desquamation by dissolution of intercellular cement material.

Autoradiography↗
PubMed1976

The epidermis in thyroid disease.

Epidermal dimensions, replication and anabolic activity have been studied in thirteen patients with thyrotoxicosis and seven patients with hypothyroidism. Epidermal thickness and rete pattern were significantly reduced in hypothyroidism. The rates of epidermal cell division and anabolic activity in the epidermis were estimated by measuring the rates of incorporation of tritiated precursor compounds and were found to be increased in thyrotoxicosis. The mean autoradiographic labelling indices after the intracutaneous injection of tritiated thymidine were 9-1% in thyrotoxic patients and 4-3% in the hypothyroid group. None of the changes observed could be correlated accurately with the degree of thyroid gland activity, but increased thyroid activity was reflected in the epidermal changes better than decreased thyroid activity.

Adolescent↗
PubMed1976

Hair follicle kinetics in psoriasis.

The rate of epidermal cell production has been measured in the various parts of scalp hair follicles in patients with psoriasis of the scalp, and in controls with normal scalp skin. An in vitro technique was used in which thin tissue slices were exposed to tritiated thymidine enabling cells about to divide to become autoradiographically labelled. Biopsies from thirteen patients with psoriasis and nine controls were examined in this way. The labelling indices of the interfollicular epidermis was 27-5% in the psoriatics and 9-5% in the controls. The upper part of the external root sheath had a labelling index of 28% in the psoriatic group compared to 13-9% for the controls. The labelling indices of the sebaceous glands, matrices and external root sheaths were very similar in the two groups. The findings support the hypothesis for a dermal stimulating influence causing the increased epidermopoiesis seen in psoriasis.

Adult↗