Human Sebum Research Articles

Variation of skin surface lipid composition among mammals

1. 1. The skin surface lipids of 46 species of mammals were extracted from fur samples with chloroform and analysed by thin layer chromatography. 2. 2. Within the families Canidae, Bovidae and Equidae, there was much similarity in composition of the surface lipids among species. In other families, including Procyonidae, Sciuridae and Mustelidae, there were considerable differences among related species. 3. 3. Between families there were profound differences in surface lipid composition, such that quite different classes of lipids were present. 4. 4. Only three species, the otter ( Lutra canadensis), beaver ( Castor canadensis) and kinkajou ( Potos flavus) produce surface lipids containing squalene, one of the principal constituents of human sebum.

Differential thermal analysis of human sebum as a new approach to rheological behaviour

Synopsis The oily aspect of a hair is not only the consequence of an excessive lipidic production on the scalp; the quality of the fatty mixture should also be considered. Differential scanning calorimetry (DSC) is a useful tool for qualitative examination of human sebum. The melting curves recorded using this technique characterise the seborrhoeic state of the subject, their profile being related to the clinical appreciation. Data from DSC are correlated with other physico-chemical characteristics of sebum, especially with the proportion of unsaturated fatty acids in the whole fatty acids fraction. The straight chain monoenic acids have been more closely examined. A number of positional isomers can be seen; the distribution of the C(18) isomers varies according to the seborrhoeic state of the subject.

Characteristic gamma-lactone odor production of the genus Pityrosporum.

Mass spectrometric-gas chromatographic analysis of culture headspaces revealed that members of the genous Pityrosporum produce volatile gamma-lactones during growth on lipid-containing media. Representative members of other yeast genera found on humans failed to produce these compounds. Addition of lecithin, oleic acids, triolein, or human sebum to the culture media stimulated gamma-lactone production by Pityrosporum species. All yeasts tested produced isopentanol and phenylethanol. Production of gamma-lactones may serve as a valuable characteristic in the identification of organisms of the genus Pityrosporum.

Enhancement of comedogenic substances by ultraviolet radiation.

Ultraviolet radiation enhanced the capacity of human sebum, sulphur, cocoa butter, squalene, and coal tar to produce comedones in the external ear canals of rabbits. An enhancement of the comedogenicity of coal tar and squalene was similarly demonstrated in man. We conjecture that in occasional patients sunbathing may aggravate acne by augmenting the comedogenicity of sebum.

Changes in the Fatty Acid Composition of Human Sebum with Age

Changes in the Fatty Acid Composition of Human Sebum with Age

The effect of some topically administered C18-, C19- and C21-steroids and a dodecahydrophenanthrene on human sebum production.

The effects of topically applied steroids and of a dodecahydrophenanthrene were investigated by means of the sebaceous gland response. Compared with testosterone (= 1) the effects of 5α-dihydrotestosterone and 5β-dihydrotestosterone were found to be 0.6 and 0.26, respectively. Epitestosterone was ineffective in females, whereas in some males an increase in sebum production was observed. The following steroids showed no significant effects with regard to an inhibition of sebum production: Retroprogesterone (Duphaston), 17α-allyl-retrotestosterone, allylestrenol, Δ1-6-chloro-retroprogesterone. The nonsteroid Ro 5-2537 [2-(1-ethinyl-1-hydroxyethyl)-7-oxo-1, 2,3,4,4α,4β,5,6,7,9,10,10α-dodecahydrophenanthrene]-caused in all subjects a significant decrease in sebum production.

Fish cutaneous mucus: A new source of skin surface lipid

AbstractMucus from several species of marine fishes contained up to 20 times more lipid per unit area than human sebum. The analyses revealed free fatty acids which may provide protection against bacterial and fungal attack. Carotenoids were prominent components. The amount of phospholipids present in fish mucus seems to determine its viscosity.

Comedogenicity of Human Sebum

The components in human sebum that mediate the formation of comedones in the rabbit ear were evaluated by applying various sebum fractions as well as individual authentic components of sebum. Practically all the major constituents of sebum had some activity. The activities of the triglycerides and waxes were respectively moderate and weak. Among the saturated fatty acids activity began at C10, reached a peak at C12and C14, lessened at C16and C18, and was absent at C20. Monounsaturation increased comedogenicity but high unsaturation had the opposite effect. Irritancy and comedogenicity were shown to be unrelated properties. The lower fatty acids C3and C5were highly irritating and noncomedogenic while C16and C18were comedogenic and non-irritating. The sebum of various animals had borderline comedogenicity because of the absence of triglycerides and fatty acids.

Studies of Soiling and Detergency

A study was made of the transfer of compounds, similar to those found in human sebum, from cellulose to polyethylene terephthalate films and the deposition of these soils on polymer films from surfactant and aqueous solutions. The polymer films were used as end windows of a Geiger tube. The soils were labeled with radioactive 14carbon so that the amount of sorbed material could be continuously monitored. The effect of variables such as detergent type, detergent concentration, temperature, sorption time, addition of sodium carboxymethylcellulose, and soil concentration on deposition have been investigated. Results are discussed in terms of possible mechanisms for soil depo sition and changes in wash conditions that should reduce deposition on man-made polymers.

Identification of pristane in human sebum and related lipid sources

Identification of pristane in human sebum and related lipid sources

Pathogenesis of acne vulgaris. II. Histopathology of comedones induced in the rabbit ear by human sebum.

The daily application of human sebum for two weeks to the external canal of the rabbit ear induced the following histologic changes: (1) hyperplasia of the epidermis and epithelial linings of the sebaceous ducts and follicles, (2) distention of the ducts and follicles with keratinized squamae to form horny impactions or comedones, and (3) variable inflammatory changes exemplified by follicular pustules and infiltration of the dermis by mononuclears and polymorphonuclear leukocytes. The comedogenic potency of sebum is considerably less than that of a chemical acneigen such as Halowax 1014. The comedones were smaller and never attained maturity.

Pathogenesis of Acne Vulgaris

The daily application of human sebum for two weeks to the external canal of the rabbit ear induced the following histologic changes: (1) hyperplasia of the epidermis and epithelial linings of the sebaceous ducts and follicles, (2) distention of the ducts and follicles with keratinized squamae to form horny impactions or comedones, and (3) variable inflammatory changes exemplified by follicular pustules and infiltration of the dermis by mononuclears and polymorphonuclear leukocytes. The comedogenic potency of sebum is considerably less than that of a chemical acneigen such as Halowax 1014. The comedones were smaller and never attained maturity.

Effect of Orally Administered Antibacterial Agents on Titratable Acidity of Human Sebum

Human surface lipid causes an inflammatory reaction in the skin when injected intradermally (1). Histologically, the inflammation is lymphocytic in type and resembles the early inflammatory changes observed after follicular rupture in acne vulgaris. The free fatty acid component of surface lipid is chiefly responsible for inducing this response, and it is likely that free fatty acids within the pilosebaceous follicle are important for the development of inflammatory acne lesions. Reduction in the concentration of free fatty acids would be expected, then, to reduce the severity of the disease. In a previous paper it was shown that the oral administration of tetracycline decreases the titratable acidity of surface lipid from the skin surface in both normal individuals and those with acne (2). This reduction in free acidity was not accompanied by any change in the concentration of total fatty acids or in the rate of sebum secretion. In the subjects who had acne, the reduction in the free acids was accompanied by clinical improvement. The present studies were undertaken to determine whether other antibacterial compounds share with tetracycline this capacity to reduce the concentration of free acidity of skin surface lipid. Data will be presented on the effect of the oral administration of penicillin, erythromycin, demethylchlortetracycline, sulfisoxazole and sulfadimethoxine on the titratable acidity of surface

Fractionation and Analysis of Components from Human Sebum

A general procedure is advanced for the separation of components in human sebum extracted from hair by means of petroleum ether toward gas chromatographic analysis. The hair was pooled according to sex, race and scalp condition. The sebum was saponified with 20% alcoholic sodium hydroxide and the unsaponifiable portion removed with ethyl ether. Chromatography of this mixture in petroleum ether over alumina and elution of the column with petroleum ether over alumina and elution of the column with petroleum ether as such and containing 5% and 10% chloroform, then 100% chloroform and finally methanol, lead to five eluates, hydrocarbons being present in Fractions I, II and III and alcohols and sterols in Fraction V. Fraction I contained squalene and waxy hydrocarbons rich in C30-paraffins, among others. Fractions I, II and III were analyzed for squalene by gas chromatography and the overall value agreed well with those employing sebum or the unsaponifiable mixture.

Activity of the acetabular secretory apparatus of cercariae of Schistosoma mansoni under experimental conditions

A combination of experimental and histologic techniques was employed to demonstrate the two pairs of preacetabular glands and ducts and the three pairs of postacetabular glands and ducts of cercariae of Puerto Rican Schistosoma mansoni. By these techniques secretion from the preacetabular secretory apparatus, either unstained or stained intravitally with purpurin, was induced into skin, on a surface of human sebum rubbed on a substratum, and into a vaseline wall rimming a coverglass sealing a mount of cercarial suspension. These glands were emptied during the initial stages of skin penetration during which schistosomules migrated along the keratogenous zone of skin and across the cellular epidermis. It was observed that cercariae deposited mucoid (PAS-positive) secretion from the postacetabular secretory apparatus as they looped over skin during exploration, at the site of penetration, and into the horny layers and keratogenous zone. Both types of glands were unstained, and therefore considered exhausted of their contents, shortly after the beginning of penetration in single penetrants, when maximum effort appeared to have been required for entry. Occasional schistosomules which penetrated in groups or which entered areas already invaded retained remnants of glandular contents which showed specific stain. It is suggested that the mucoid postacetabular secretion serves adhesive, lubricative, protective and enzyme-directive functions, while the preacetabular secretion is primarily enzymatic. The possibility remains, however, that secretions from both pre- and postacetabular glands may be active enzymatically.

Examination of lipids in human sebum by disk chromatography.

Examination of lipids in human sebum by disk chromatography.

Studies of sebum. 8. Observations on the squalene and cholesterol content and the possible functions of squalene in human sebum

Studies of sebum. 8. Observations on the squalene and cholesterol content and the possible functions of squalene in human sebum

Studies of sebum. 6. The determination of the component fatty acids of human forearm sebum by gas-liquid chromatography.

Studies of sebum. 6. The determination of the component fatty acids of human forearm sebum by gas-liquid chromatography.

Some Observations on the Nature, Origin and Possible Function of the Squalene and Other Hydrocarbons of Human Sebum

In a study of the general composition of the surface skin fat or sebum from the human forearm (MacKenna, Wheatley and Wormall (1)) it was found that this material contains a high proportion of hydrocarbons constituting about half the non-saponifiable matter or about one-sixth of the whole sebum. Squalene was identified as one of the major constituents, accounting for about one-third of the total hydrocarbons. At about the same time Sobel (2) showed that this substance was a normal constituent of human hair fat, ear wax and smegma, and Cmelik, Petrak-Longhino and Mihelic (3) established its presence in vernix caseosa. The presence of squalene in these sebum and sebum-like materials presents an interesting biochemical problem as to its origin and possible func- tions in the skin. Its role is even more significant as it appears to be a possible intermediary in the metabolism of cholesterol (Langdon and Bloch (4)). We have also found that paraffins are present in the hydrocarbon fraction of human sebum (5, 6) and we now report some investigations which have been made in an endeavour to elucidate the role played by the sebum hydrocarbons.

The constitution of the aliphatic alcohols in human sebum.

The constitution of the aliphatic alcohols in human sebum.