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Biomedical subjects

R Marks

Publications and source records attributed to R Marks.

At least 361 records · Page 20Linked to original sources
PubMed1985

Detection of the effects of low dose ionising irradiation on epidermal function.

A non-invasive technique for the detection of small doses of X irradiation to the skin would be important for improvements in radiation protection. In this investigation we have studied the effects of doses of X rays of less than 2.0 Gy (suberythemal) on human skin in order to select such a technique. Our results indicate that a dose of X rays between 0.5 and 1.0 Gy was sufficient to depress significantly epidermal cell production in the basal layer. Accompanying this change in epidermal cell production after 1.0 Gy exposure, there was a reduction in the rate of desquamation of corneocytes. In the stratum granulosum, changes in "non-specific esterase" activity (a marker of lysosomal enzyme release) were also observed. Thus at three stages of the keratinisation process, functional alterations had occurred within three days of exposure to an X ray dose of 1.0 Gy. For this reason it seems likely that the various changes were at least partially independent of each other and that the stratum corneum may serve as a biological dosimeter for the detection of exposure to low doses of ionising radiation.

Aged↗
PubMed1985

Clinical, histologic, and cell kinetic discriminants between lamellar ichthyosis and nonbullous congenital ichthyosiform erythroderma.

Patients described as having lamellar ichthyosis (LI) may not all have the same disorder. We studied nine patients, four of whom had erythroderma and generalized fine scaling, while the remainder had more marked scaling and hyperkeratosis without erythema. The former group is referred to as having nonbullous congenital ichthyosiform erythroderma (CIE), and the other is said to have LI. The clinical differences were paralleled by cell kinetic and histologic differences. The mean tritiated thymidine autoradiographic labeling indices were 9.36 +/- 4.05 and 19.70 +/- 5.84 for the LI and CIE groups, respectively. The histologic differences were delineated using 10-cm analogue scales and showed statistically significant differences for hyperkeratosis and parakeratosis. These data support the hypothesis that LI and CIE are separate disorders.

Adolescent↗
PubMed1985

Quantitative evaluation of the dermal vasculature of diabetics.

The dermal microvasculature has been compared in 51 diabetics and 51 matched non-diabetic controls using tissue measurement techniques and functional assessments of blood vessel reactivity. Blood vessel walls were thicker in different groups of diabetics than the controls (p less than 0.01) but the degree of thickness did not differ between patients with insulin-dependent diabetes mellitus and those with non-insulin-dependent diabetes mellitus or between diabetics with and without vascular complications. Vascular lumina were narrower in diabetics than in controls (p less than 0.01) and diabetics with vascular complications had a greater reduction in luminal area than those without such complications (p less than 0.001) but the luminal area did not differ between the insulin-dependent and the non-insulin-dependent groups. The luminal perimeter was also reduced in the diabetic group compared to controls. The weal and flare response to intracutaneous histamine acid phosphate (50 micrograms) was markedly decreased (p less than 0.001) in diabetic subjects compared with controls, as was the response to a topically applied vasodilator (Transvasin). The degree of reduction did not differ between patients with insulin-dependent diabetes mellitus and those with the non-insulin-dependent disease but diabetics with vascular complications show impaired responses as compared to those without. The maximum increase in skin temperature on the volar surface of the right middle finger during a period of reactive hyperaemia following 3 min of cuff-induced ischaemia was also markedly decreased in diabetics compared with control subjects. It did not differ between those with insulin-dependent diabetes mellitus and those with the non-insulin-dependent disease but did between diabetics with vascular complications as compared with those without. This study confirms that the cutaneous vasculature of diabetics differs markedly from that of matched control subjects. The results also indicate that there are significant differences between diabetics with vascular complications and those without. The quantitative approaches adopted may have predictive value.

Adult↗
PubMed1984

Facial rashes.

Explore the source record for details and available documents.

Facial Dermatoses↗
PubMed1984

Geographic tongue: sensitivity to the environment.

The prevalence of geographic tongue was assessed among 102 atopic patients with extrinsic asthma and/or rhinitis and was found to be significantly greater in these patients than in an asymptomatic, nonatopic control population. However, there was no difference between the prevalence of geographic tongue among atopic patients with extrinsic asthma and rhinitis as compared to a group of patients with asthma and rhinitis who were not atopic. These findings suggest that geographic tongue is a sign common to those patients who have a tendency to develop recurrent acute inflammatory disease on surfaces in contact with the external environment (for example, asthma or rhinitis), whether they are atopic or not.

Adolescent↗
PubMed1984

Factor XIII inhibits epidermal cell migration in vitro.

The effect of a factor XIII preparation on active epidermal cell migration in vitro has been studied using both floating and attached types of human skin explants in short-term maintenance cultures. In both types of experiment the factor XIII preparation proved to have an inhibitory effect on epidermal cell migration in a dose-dependent fashion. This effect was shown to be independent of both the presence of fibrin and the concentration of calcium ion in the medium. The preparation also showed inhibition of the proliferation of epidermal cells in cell culture.

Adult↗
PubMed1984

Follicular ichthyosis.

We describe four patients with congenital follicular hyperkeratosis, of whom three also had pseudoacanthosis nigricans and two had facial abnormalities. Skin specimens were studied by light microscopy, autoradiography, histochemistry and scanning electron microscopy, and the results were compared with those from patients with keratosis pilaris. The condition appears to constitute a distinctive form of ichthyosis in which the abnormal epidermal differentiation occurs mainly within the hair follicles.

Adolescent↗
PubMed1984

The effect of serum calcium levels on the rate of epidermal renewal in the rat.

The growth and differentiation of epidermal cells in vitro show a marked dependence on the calcium concentration of the medium. In this study the effect of experimentally produced hyper- and hypocalcaemia on the rat epidermis in vivo has been investigated. Hypercalcaemia, induced by injections of calcium chloride, produced a decrease in epidermal labelling index and some epidermal thinning. On the other hand hypocalcaemia, induced by calcitonin, failed to lead to changes in these measurements. The diurnal variation in epidermal labelling index and serum calcium levels was also measured. Whilst the labelling index decreased considerably over the period 09.00 hours to 18.00 hours, no significant changes were observed in serum calcium. These results suggest that while, under certain circumstances in vivo, the epidermal cell shows the same sensitivity to calcium as it does in vitro, calcium is not a major regulator of epidermopoiesis.

Animals↗
PubMed1984

Analysis of the non-ionic detergent-soluble lipids of human stratum corneum.

Mechanical stimulation of the skin surface in the presence of non-ionic detergent (Triton X-100)-containing buffers has been used to prepare isolated corneocytes and non-ionic detergent-soluble (NIDS) material from human stratum corneum. Analysis of the major lipid classes present in the corneocytes and NIDS material has been performed by thin layer chromatography with flame ionization detection and quantitation based on the introduction of an internal standard. Results indicate that the NIDS lipid represents a disproportionately large amount of the total stratum corneum lipid and that it differs in composition from the corneocyte lipid, there being a greater proportion of the cholesteryl ester fraction in the corneocytes. Both these findings support the 'brick wall' model of the stratum corneum and provide further evidence that the NIDS material is intercellular in nature.

Chromatography, Thin Layer↗
PubMed1984

A simplified method for measurement of desquamation using dansyl chloride fluorescence.

A fluorescence comparator has been used to assess quantitatively the skin fluorescence due to applied dansyl chloride. Experiments were performed demonstrating that measurements with the device had a low intra- and inter-observer error, with coefficients of variation of between 4% and 6%. Another experiment in which fluorescence photographic photometry was simultaneously performed showed that the comparator provided estimates of stratum corneum renewal similar to the more complex photographic technique. Repeated mechanical trauma to the skin and skin stripping showed that the technique can detect alterations in the rate of cell renewal in the epidermis.

Adult↗
PubMed1984

Studies of the clinically uninvolved skin in patients with dermatitis.

We have studied the clinically normal skin of eighty-four patients with quiescent dermatitis of different types, and fifty normal subjects. Increased susceptibility to chemical irritation was demonstrated in patients with atopic and exogenous dermatitis. There was a reduction in mean corneocyte area and a thinner horny layer in all patients, and an increased epidermal thickness in atopic dermatitis patients only. In forced desquamation studies, patients released more corneocyte clumps from the skin surface, but there were no significant differences between patients and controls in sensitivity to UVR or electrical conductivity.

Adolescent↗
PubMed1984

Inflammation caused by intracutaneous implantation of stratum corneum.

When an epidermoid cyst ruptures, a granulomatous infiltrate develops around the damaged structure. The same is true when other horn-containing cysts release their content into the epidermis. A similar type of inflammation may be observed in the dermis around disrupted and horn-filled follicles in acne vulgaris. In this paper we describe experiments in which a granulomatous inflammation has been produced in guinea-pig skin by the intracutaneous implantation of stratum corneum and discuss the potential of this system as a model for the inflammation in acne.

Acne Vulgaris↗