Hand cleansing and skin condition. A comparison of conventional soap washing and the use of alcohol-impregnated paper cloths.

Synopsis By means of a controlled hand-cleansing trial on normal volunteers with no observable skin problems, we have compared the action of a high frequency of washing the hands with soap and water with the use of alcohol-impregnated paper towels, using visual assessment of hand dryness by a trained operator as the criterion of skin condition. High frequency of soap-and-water washing (10 times daily) elicits a significantly higher level of hand dryness than a frequency of 1-2 times daily. This effect, although transient, indicates a gradual build-up of a higher prevailing level of hand dryness with sustained higher frequency washing. Use of the alcohol-impregnated towels even at this higher frequency of 10 times per day does not elicit the observed level of hand dryness seen with soap washing.

A comparative study of hepatic and epidermal histidase in the guinea-pig (Cavia porcellus).

Histidine ammonia lyase was purified to homogeneity from guinea-pig liver and epidermis. Both enzymes had similar molecular weights, subunit composition and pH optima. Km values for the two were similar at pH 9.2 but different at pH 7.0. Both enzymes were stimulated by low thiol concentrations and inhibited at higher concentrations, but to different extents. Antibody to the hepatic enzyme showed complete identity against hepatic enzyme but incomplete identity against epidermal enzyme.

Identification, isolation and characterization of epidermal lipids containing linoleic acid.

Three specific linoleate-rich lipids have been identified in pig epidermis and are referred to as O-acylglucosyl ceramide, O-acyl ceramide, and O-acyl acid. The acid moiety is up to 70% linoleic acid and linked via the hydroxyl group of a omega-OH long-chain fatty acid, which itself is linked to sphingosine or glucosyl sphingosine. The identification of O-acyl ceramide confirmed the findings of another group, whereas the structural configuration of the O-acylglucosyl ceramide is different to previous reports. The identification of an O-acyl acid in epidermis is novel. Our evidence allows us to speculate that a hydroxylated derivative of the O-acyl ceramide may be intimately involved in the permeability barrier of skin, perhaps providing sufficient polarity to maintain a lamellar phase in the intercellular space of the lower stratum corneum region, and that it is specifically in this form that linoleic acid is involved in skin barrier function. Alternatively, or concurrently, this species may act as a signal for late keratinisation events.

The mode of action of ethyl lactate as a treatment for acne.

We have shown that an alcoholic lotion containing ethyl lactate when applied topically to rat skin under occlusion became localized in the follicles and sebaceous glands. When applied to human facial skin the ethyl lactate was hydrolysed to ethanol and lactic acid, and thereby lowered the skin pH. Under such conditions the growth of recoverable skin bacteria, in particular the anaerobe Propionibacterium acnes, was inhibited, and the hydrolysis of sebum to free fatty acids by lipase derived from the bacteria was greatly impaired. These effects of ethyl lactate would account for its observed clinical efficacy in acne vulgaris.

Prediction and measurement of surfactant action upon human skin under realistic conditions.

Synopsis The lysosomal enzyme acid phosphatase has been characterized and quantified in tapestrip biopsies of human stratum corneum by means of a sensitive spectrofluorometric procedure. When the stratum corneum of panellists was exposed to dilute solutions of various surfactants under realistic exposure conditions, the changes observed in stratum corneum acid phosphatase specific activity have been found to correlate very closely with the visual, macroscopic changes such as dryness and flakiness, that are elicited in skin as a result of surfactants. This method monitors denaturation of stratum corneum proteins, which is an important feature of skin surfactant interactions, and serves as an effective, non-invasive predictive tool for skin irritancy and mildness of surfactants. Prevention et mesure de l'action des tensio-actifs sur la peau humaine dans des conditions conformes a la réalité

Trimethylaminuria: the use of choline as an aid to diagnosis.

Trimethylamine metabolism can be studied by means of choline loading. The value and some limitations of the method are illustrated by results obtained in normal subjects, a patient with the Fish Odour syndrome and his kindred.

Changes in transepidermal water loss and the composition of epidermal lecithin after applications of pure fatty acid triglycerides to skin of essential fatty acid-deficient rats.

The importance of various unsaturated fatty acid triglycerides to the repair of faulty skin barrier function was studied in essential fatty acid-deficient rats. Following cutaneous application of the pure triglycerides for up to 5 days, the hitherto high rate of transepidermal water loss, characteristic of essential fatty acid deficiency in rats, was reduced by the triglycerides of linoleic and gamma-linolenic acids. Incorporation of the applied fatty acids into the lecithin of the epidermis accompanied these changes in water loss, indicating that cutaneously applied triglycerides may be metabolized by the skin and incorporated into complex lipids. Other fatty acid triglycerides, including alpha-linolenic, dihomo-gamma-linolenic, arachidonic and omega-7-heneicosatrienoic acid, did not lower the rate of transepidermal water loss, although all were incorporated into epidermal structural lipids. The non-essential oleic acid also had no effect upon the rate of transepidermal water loss. These data suggest that of the two main essential fatty acids that occur in skin, linoleic acid and arachidonic acid, the former specifically plays an important role in regulating barrier function whereas the later may have a separate function, such as serving as a precursor of prostaglandins.

The repair of impaired epidermal barrier function in rats by the cutaneous application of linoleic acid.

Epidermal barrier function in rats was experimentally impaired by two separate means, namely, by rendering the animals deficient in essential fatty acids and by evoking a primary cutaneous irritant response by treating with a solution of sodium laurate. Impaired barrier function was manifested by a greatly increased rate of transepidermal water loss. Application to the skin of sunflower seed oil, which is rich in linoleic acid, rapidly restored to normal the abnormally high rates of transepidermal water loss in both experimental cases, and it was shown with the essential fatty acid-deficient rats that there was a concomitant incorporation of linoleic acid of the sunflower seed oil into epidermal lipids. Cutaneous application of olive oil, which is low in linoleic acid but rich in the non-essential oleic acid, did not influence epidermal barrier function. A close relationship of barrier function and essential fatty acids is indicated.