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Biomedical subjects

M Lodén

Publications and source records attributed to M Lodén.

27 records · Page 2Linked to original sources
PubMed1992

Friction, capacitance and transepidermal water loss (TEWL) in dry atopic and normal skin.

The biophysical properties of non-eczematous skin at three locations in atopics and non-atopics were characterized using non-invasive physical methods. Skin friction was measured with a newly developed sliding friction instrument, the degree of hydration with a capacitance meter (Corneometer CM 820), and the transepidermal water loss (TEWL) was determined using an Evaporimeter EP1. The areas examined (dorsum of the hand, volar forearm and lower back) showed lower values of friction and capacitance in the atopic patients than did corresponding sites in the normal controls. In most areas a significant correlation between friction and capacitance was found. The TEWL was increased in atopic skin, but TEWL seems to correlate neither to friction nor to capacitance.

Adult↗
PubMed1992

The increase in skin hydration after application of emollients with different amounts of lipids.

Emollients can increase the water content in the stratum corneum by delivery of their water to the skin, and by occlusion. These two mechanisms were studied using three preparations with different concentrations of lipids. The products were applied to the skin and then removed by cleaning the surface after 5 and 40 min. The increase in skin water loss following removal of product residue was considered as a release of excess water in the skin. Exposure of the skin to pure petrolatum for 5 min gave no increase in the water loss from the skin surface following removal of the product residue. A lipid rich cream (66% lipids) gave a significant increase, but the highest increase was found after removal of an ordinary cream (27% lipids). Release of water from the skin indicates that water in the creams had previously been absorbed into the skin. The occluding properties of the products were determined after 40 min of exposure. Petrolatum reduced the water loss by approximately 50% and the other products by 16%. The occlusion caused an increase of water in the skin, which resulted in a release of water following removal of the products. The release was related to the reduction of water loss. Thus petrolatum gave a higher release of water than the other emollients.

Administration, Cutaneous↗
PubMed1991

The influence of a single application of different moisturizers on the skin capacitance.

Moisturizers are believed to improve the skin condition by increasing the water content of the stratum corneum. A variety of techniques for assessing skin hydration has been developed. In the present study the capacitance following a single application of different moisturizers to normal skin on 12 volunteers was measured with the commercial available Corneometer 420. The moisturizers were pure petrolatum and three oil-in-water creams. The latter contained either glycerine, glycerine and pyrollidone carboxylic acid, or urea as humectant agents. The first measurement of the change in the capacitance was done 2 h after application of the products. All tested products increased the capacitance in the same order of magnitude. For the creams the values were significantly enhanced during the experimental period (6 h). Excess product were removed from some skin areas after the 2 h measurement. This caused immediately a significant decrease in the capacitance of the cream treated sites, whereas a tendency towards higher values were noted on the petrolatum-treated sites. These findings indicate that the non-absorbed components influences the capacitance values. Hence, the interpretation of electrical measurements with respect to skin moisture should be made with caution.

Adult↗
PubMed1989

'Dry' skin in atopic dermatitis. II. A surface profilometry study.

In patients with atopic dermatitis, the skin is often 'dry' on non-eczematous areas, and feels rough to the touch. In the scanning electron microscope (SEM) this roughness corresponds to a change in the skin surface, from regular major and minor furrows into a coarse and irregular pattern. In the present study the topography of normal skin and 'dry' atopic skin was quantitatively recorded using a profilometry method. A computer-based three-dimensional reconstruction of the skin surface was made from replicas, and common roughness parameters were calculated. It was found that in the 'dry' atopic skin roughness parameters Ra, Rq, and Rmax, were significantly increased, whereas the number of peaks, Rn, was decreased. Parameters describing the shape (skewness, kurtosis, and delta a) of the profile were not significantly different. These topographical data clearly support the visual impression of the surface pattern of 'dry' atopic skin found in SEM.

Adolescent↗
PubMed1986

The effect of 4 barrier creams on the absorption of water, benzene, and formaldehyde into excised human skin.

The effect of 4 barrier creams on the absorption of (3H)-water (14C)-benzene and (14C)-formaldehyde into excised human skin was studied. The control skin and the barrier cream treated skin were exposed to the test substance for 0.5 hr, whereupon the amount absorbed was determined. The results indicated that the experimental cream "Water barrier" reduced the absorption of water and benzene but not formaldehyde. Kerodex 71 cream slightly reduced the absorption of benzene and formaldehyde. The barrier creams Petrogard and "Solvent barrier" did not affect the absorption of any of the substances studied. The use of these creams against percutaneous absorption is questioned.

Benzene↗
PubMed1986

The in vitro permeability of human skin to benzene, ethylene glycol, formaldehyde, and n-hexane.

The permeability of human skin to benzene, ethylene glycol, formaldehyde, and n-hexane was studied using excised skin in a flow-through diffusion cell. The rate of resorption was determined by measuring the amount of substance found in the receptor fluid beneath the skin at steady-state. The rates of resorption (microgram X cm-2 X hr-1) were: benzene 99. ethylene glycol 118, formaldehyde from a concentrated solution of formalin 319, formaldehyde from a solution of 10% formalin in phosphate buffer 16.7, and n-hexane 0.83. The amount of substance in the skin at steady-state and after 0.5 hr of exposure was also determined. For all substances, the sum of the amount in the receptor medium and in the skin at steady-state, were larger than the amount obtained by multiplying the resorption rate by the time of exposure. For benzene, ethylene glycol and n-hexane the amount absorbed during the first half-hour of exposure was considerable larger than the amount resorbed during a same unit of time at steady-state. These data call attention to the fact that the absorption rate is higher before steady state is attained.

Benzene↗
PubMed1985

The in vitro hydrolysis of diisopropyl fluorophosphate during penetration through human full-thickness skin and isolated epidermis.

Skin may play an important role in the detoxification of certain substances during their passage into the body. The degree of hydrolysis of diisopropyl fluorophosphate, DFP, in skin suspensions and during penetration through isolated epidermis and full-thickness skin from humans was investigated in vitro. When isolated sheets of epidermis were used, 11% of the penetrated amount of DFP was hydrolyzed whereas 46% was hydrolyzed during penetration through full-thickness skin. A comparison is made between the degree of hydrolysis during penetration as obtained from direct measurements and that calculated from kinetic data of the enzyme (Kappm and Vappmax), the half-life of DFP, the skin concentration, and the lag time. The concentration of DFP in the skin was not measured, but the concentration of DFP equivalents (DFP and metabolites formed during penetration) was determined at different times. At steady state, the amount of DFP equivalents in the skin corresponded to the amount that had penetrated into the skin during the lag time. This indicates that the penetration rate corresponded to the uptake via the skin and that no diffusion barrier existed between the skin and the receptor medium. It was also found that the concentration in the skin was proportional to the penetration rate, thus indicating that the enzymatic degree of hydrolysis depends upon the penetration rate.

Adult↗
PubMedDate not supplied

Skin-identical lipids versus petrolatum in the treatment of tape-stripped and detergent-perturbed human skin.

The cutaneous permeability barrier is localized to the stratum corneum interstices and is mediated by lamellar bilayers enriched in cholesterol, free fatty acids and ceramides. Topically applied lipids may interfere with the skin barrier function and formulations containing "skin-identical lipids" have been suggested to facilitate normalization of damaged skin. The aim of the present study was to compare the ability of "skin-identical lipids" in a petrolatum-rich cream base and pure petrolatum to facilitate barrier repair in detergent- and tape-stripped-perturbed human skin. Barrier recovery and inflammation were instrumentally monitored for 14 days as transepidermal water loss and skin blood flow, using an Evaporimeter and a laser Doppler flowmeter, respectively. Treatment with the 2 different products gave no indication that "skin-identical lipids" in a cream base are more efficient than pure petrolatum at promoting normalization in either of the 2 experimentally perturbed areas. This finding may support the hypothesis that different types of skin abnormality should be treated according to the underlying damage.

Administration, Topical↗