THE EFFECT OF ENZYME DETERGENTS ON TRANSEPIDERMAL WATER LOSS FROM NORMAL SKIN

Summary.— Transepidermal water loss from normal forearm skin was measured in 15 normal subjects before and after a standardized "skin insult" produced by friction with a detergent alone or with the detergent plus proteolytic enzyme. No statistically significant difference was discernible between the results obtained with the two solutions.     

TRANSEPIDERMAL WATER LOSS IN PATIENTS WITH DERMATITIS

SUMMARY.— Using an electrolytic hygrometer, the Transepidermal Water Loss (T.W.L.) from the skin was measured in normal individuals and in patients with dermatitis (eczema). It was found that there was a close correlation between T.W.L. and the state of activity of the dermatitis; and that there was a gradual reduction in abnormally raised T.W.L. in parallel with the return to normal of the skin response (dermatitis). Sweating did not contribute to the increased insensible water loss in dermatitis under the fixed limits of ambient temperature and humidity of this investigation.     

THE DIURNAL VARIATION OF WATER VAPOUR LOSS FROM THE SKIN IN RELATION TO TEMPERATURE

SUMMARY.— The water vapour loss from irritated and non-irritated skin sites was determined twice daily during a period of 19–42 days after the irritation. Diurnal variation of skin temperature gives anomalous values for water vapour loss but does not account for anomalous activation energies.     

MEASUREMENT OF THE SKIN-CLEANING EFFECTS OF SOAPS

Background. In the past 30 years, many tests for assessing the irritancy of soaps have been introduced, but only very few tests for evaluating their cleaning properties. The urgent need for such a method is obvious. Methods The method is based on the principles developed by Schrader, with substantial modifications. As in Schrader's method, we used a fat-based ointment to emulate “dirt.” The washing process was performed by placing the examined hand in a rotating soap solution for 5 minutes. The capacity of various soaps to remove the “dirt” was assessed by comparing the sebumeter readings before and after the washing process. The difference between the two readings provided a quantitative estimate of the percentage of “dirt” (ointment) that was washed off during the process. Results The cleansing capacity of two soaps was compared to that of water. Soap 1 showed a cleansing of 81.7 ± 2.4%, soap 2 a cleansing of 75.3 ± 2.9%, as compared to water of 29.7 ± 3.4%. The curve representing the distribution of the data was very smooth, bell-shaped and symmetric about its mean. The difference between the cleaning activity of the two soaps tested was statistically significant (P < 0.0001). Conclusions We have presented a new method for testing the cleansing capacity of soaps. We believe, that our method gives better results than that of Schrader; in particular, it enables us to discriminate more effectively among the various soaps. Our results indicate that the method is reliable and reproducible. It is also practical, easy to perform, does not require an expensive and complex washing machine, and can be carried out in every laboratory.     

LOSS OF THE ANTIBACTERIAL ACTION OF SKIN AFTER TOPICAL NEOMYCIN

SUMMARY. .
Neomycin-resistant strains of Staphylococcus aureus were found to persist longer on skin treated with neomycin than on untreated skin. The mechanism is probably the neutralization of the natural antibacterial action of the skin by the union of neomycin with free fatty acids in the epidermis.     

THE MEASUREMENT OF SEBUM SECRETION TN THE RAT ANGELA

SUMMARY.— Surface lipids were removed from anaesthetized rats by dipping them into lipid solvent up to the neck. After varying time intervals, the lipid which had accumulated was removed and assayed gravimetrically.
The accumulation of lipid was linearly related to time up until the fourth day, after which it decreased. Passive accumulation from a reservoir of lipid was excluded by the finding that the amount of lipid extracted at 7 successive 4-day intervals did not decrease. The lipid accumulation during the first hours after solvent extraction was too rapid to be accounted for by lipid originating from growth of hair and epidermis.
It was concluded that sebum secretion was measured and the rate during the first 4 days was 13·3 ± 0·4 mg./100 G. body weight.     

THE MECHANISM OF WATER BINDING IN STRATUM CORNEUM

SUMMARY.— The results presented in this paper confirm the published observations by others that the hygroscopic water-soluble substances within the corneum are responsible for much of the water binding ability of the horny layer. The ability of corneum to bind water is reduced when it is extracted with solvents, which remove lipid, and then with water, which removes the water-soluble substances. Our interpretation of this is that the water-soluble substances are retained within the corneum by a lipid-containing semipermeable membrane system which allows these substances to take up water by osmosis and protects them from dissolution when the intact corneum is immersed in water. Our experiments show that isolated corneum from guinea-pig footpads and from human palms, soles and abdomen can take up and lose water by osmosis. Powdering the corneum allows water to extract the water-soluble substances without a prior solvent extraction. The powdering procedure ruptures the cell walls of the corneum cells and we propose that it is the cell walls which make up the lipid containing semi permeable membrane system.
A method for measuring extensibility of isolated strips of corneum in a humid atmosphere has been developed. Using this technique it has been shown that it is the water held by the water-soluble substances that is responsible for most of the extensibility of corneum.     

THE ADENYL CYCLASE OF SKIN I. MEASUREMENT AND PROPERTIES

A method is described for the measurement of cutaneous adenyl cyclase. Certain properties of the adenyl cyclase of guinea-pig skin have been studied; this enzyme appears to be unusual in that no stimulation of its activity by adrenalin could be demonstrated.     

ACCURATE MEASUREMENT OF NAIL GROWTH

The minimum normal growth of the fingernails being 0.5 mm per week makes it rather difficult to measure the nail growth within a period less than three to four weeks. It is suggested that the use of an X-ray marker will help obtain accurate measurement of nail growth within shorter periods of time, such as one week.