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At least 19 recordsLinked to original sources
PubMed1991

Formation of oiliness and sebum output--comparison of a lipid-absorbant and occlusive-tape method with photometry.

Sebum output and the development of oiliness formation were studied in 24 acne-prone volunteers. Sebutape and photometric measurement by the Sebumeter were compared. Tapes were taken 1, 2 and 3 h after degreasing. Tapes were scored, and light transmission was measured by a special densitometric device. Sebumeter recordings were performed after 3 h. Densitometric evaluation of tapes was accurate with a high correlation to scoring. Sebutape and Sebumeter assessments correlated. However, in some individuals the tape method overestimated the sebum output. Right-left comparison indicated that the tape method was less reproducible, particularly after longer sampling periods. It is suggested that Sebutape, due to water occlusion and temperature insulation during the sampling period, interferes with sebum droplet formation and spreading. However, such systematic interference may be advantageous since sweating and heat are important clinical prerequisites in the formation of oiliness. Thus, it is suggested that the Sebutape is a specialized method for the determination of 'oiliness', the very last phase of sebum output, in which sebum droplets spread over the skin surface. The tape is not automatically comparable to other methods for determining sebum output from the follicular reservoir.

Acne Vulgaris↗
PubMed1991

Responses of tsetse to ox sebum: a video study in the field.

The behaviour of tsetse (mainly Glossina pallidipes Austen) around odour-baited targets, with or without a coating of ox sebum, was recorded in the field using video. The addition of sebum increased the total time a fly was in contact with the target, as well as the time spent flying around and landing on it. When carbon dioxide was released as part of the attractant odour plume, the presence of sebum on the target increased the number of landings made by each fly, but did not significantly affect the duration of each contact. When carbon dioxide was absent from the odour plume, sebum did not affect the number of landings made by flies but the duration of each contact with the target did increase. Evidence for an interactive effect of sebum and carbon dioxide was obtained. In addition, the presence of sebum on the target increased the percentage of landed flies which walked on its surface; such behaviour may represent an 'inspection' of the artificial host. The potential tsetse control application of the current findings are discussed.

Animals↗
PubMedDate not supplied

Lipoperoxides in sebum of substance users and controls.

Sebum was collected from forehead skin in five compulsive heroin and/or cocaine (substance) users and in five controls over three consecutive periods, each lasting three hours. The participants were adult black and white men similar in age and smoking habits, who did not consume alcohol. Lipoperoxides were determined in sebum as malondialdehyde by high performance liquid chromatography. Two participants were excluded in the control group: in both, urinary lipoperoxides were elevated; in one, urine tested positive for delta-9 tetrahydrocannabinol (THC). All other participants had negative urine drug screening tests. Relative to the controls, all substance users had elevated concentrations of lipoperoxides in urine. Compared to the controls, the rate of sebum excretion in the last collecting period was higher in substance users, but sebum had significantly lower lipoperoxide concentration. It is assumed that compulsive drug use may influence lipoperoxidation of incipient sebum, possibly by altered tissue perfusion.

Adult↗
PubMed1978

Liquid chromatographic analysis of sebum lipids and other lipids of medical interest.

A technique is described for the high-pressure liquid chromatographic (HPLC) analysis of sebum lipid classes. The lipid present in sebum are separated by gradient elution HPLC from a microparticulate silica column and detected using a moving-wire detector. The system described can be linked to a computer. Quantitation can be carried out by comparing peak areas obtained with those of an internal standard. Peak trapping for further investigations of the separated components, for example by gas chromatography-mass spectrometry, is very easy. Sebum lipids are separated into the following lipid classes: hydrocarbons and squalene, cholesterol esters and wax esters, fatty acids as their methyl esters, triglycerides, 1,3-diglycerides, 1,2-diglycerides, free cholesterol, monoglycerides and other polar materials. Besides to sebum, the method has been successfully applied to other lipid mixtures, such as serum lipids. Examples of other applications are shown.

Chromatography, High Pressure Liquid↗
PubMed1992

Influence of oral metronidazole on the endocrine milieu and sebum excretion rate.

As part of a study of the mechanism of metronidazole's efficacy in the treatment of acne and rosacea, its effects on the endocrine milieu and sebum excretion rate were assessed. Thirteen healthy males received oral metronidazole treatment (500 mg/day) for 4 weeks. Serum sex hormone levels were determined in all 13 subjects and the sebum excretion rate was determined in seven of them, before and after treatment. We measured serum levels of estrone (E1), estradiol (E2), total testosterone (T), free testosterone (FT), dihydrotestosterone (DHT), dehydroepiandrosterone sulfate (DHEA-S), and sex hormone-binding globulin (SHBG). There were no significant changes in E1, T, FT, DHT, or SHBG levels, but E2 and DHEA-S levels decreased significantly after treatment. In all seven subjects in whom the sebum excretion rates were determined, the amount of facial skin surface lipids decreased significantly after treatment. These results suggest that metronidazole exerts its clinical effects through suppressing the sebum excretion by a mechanism other than anti-androgenic action.

Administration, Oral↗
PubMed1991

Skin aging. Effect on transepidermal water loss, stratum corneum hydration, skin surface pH, and casual sebum content.

This study investigates the effect of cutaneous aging on transepidermal water loss, stratum corneum hydration (capacitance), skin surface pH, and causal sebum content. Because the physiologic condition of skin varies considerably with anatomic region and skin aging might demonstrate regional variability, all factors were studied on 11 anatomic locations in 14 young adult (seven female and seven male subjects; 26.7 +/- 2.8 years [mean +/- SD]) and 15 aged human volunteers (seven female and seven male subjects; 70.5 +/- 13.8 years). Significant anatomic variability was noted for all factors in both age groups. However, no significant differences between the two groups were noted for sebum, capacitance, and pH on most anatomic regions. Transepidermal water loss, however, was significantly lower in the aged population on all anatomic regions tested, except for the postauricular region and the palm. Comparing male and female volunteers, none of the four factors showed significant differences. Of all measured factors, only transepidermal water loss showed significant age-related differences on most anatomic regions studied. The additionally observed differences between the age groups on the ankle for pH and sebum might be related to the stasis frequently observed on the lower limbs in aged individuals.

Adult↗
PubMed1991

Comparison of the kinetics of sebum secretion in young women with and without acne.

We utilized a sebum-sensitive adhesive film, Sebutape, to visualize the pore patterns of women with and without acne with computerized image analysis. In normal young women, we found a positive correlation between the number of active sebaceous follicles and total sebum excretion. When seborrhea was intense, this correlation was however lost. The situation was more complex in acne. The severity of seborrhea was positively correlated with the mean sebum excretion of individual follicles but not with the number of active follicles.

Acne Vulgaris↗
PubMed1991

Rhythm of sebum excretion during the menstrual cycle.

We studied by the Sebutape technique variations in the sebum excretion and in the number of active sebaceous glands during 3 consecutive menstrual cycles. In seborrheic women we found cyclic changes with a maximum sebum excretion during the week before menstruation. In women with a low sebum production, no changes were found.

Adult↗
PubMed1979

Effect of neonatal administration of thyroxine on the rate of sebum production in rats.

Newborn Sprague-Dawley rats of both sexes were treated with 28 micrograms thyroxine (T4) daily for the first week of life. At the age of 80 days, the secretion rate of sebum was measured from the amount of skin-surface lipids extractable by acetone and which had been produced during 2 days. Treatment with such excess amounts of T4 during the early postnatal period significantly reduced the production of sebum in both male and female rats when compared with control rats and with rats deprived of food early in life. The thyroid, the pituitary gland, the testes and the seminal vesicles were significantly smaller but the weights of the ovaries and uteri remained relatively unaffected. There was a similar ratio of sex difference in the rate of sebum secretion irrespective of treatment. It is suggested that a reduction of sebaceous response in rats made thyrotoxic with large doses of T4 early in life was probably due to a decreased secretion of thyroid hormone which is required to maintain normal activity of the sebaceous glands.

Adrenal Glands↗
PubMed1975

The effect of environment on sebum output and composition in cattle.

In an investigation into the effect of short-term exposure to different temperatures and humidities on the sebaceous glands of Ayrshire calves it was concluded that temperature had no appreciable effect on sebum output or its fatty acid composition. At a low humidity, however, the cutaneous outputs of palmitic and myristic acids were higher. On prolonged exposure to a warm environment, a higher output of sebum occurred together with an increase in the percentage of linoleic acid in the sebum.

Animals↗
PubMed1991

Terbinafine levels in serum, stratum corneum, dermis-epidermis (without stratum corneum), hair, sebum and eccrine sweat.

We determined terbinafine levels in serum, stratum corneum, dermis-epidermis (without stratum corneum), hair, sebum and eccrine sweat before, during and after 250 mg doses orally to volunteers once daily. Terbinafine is concentrated rapidly in stratum corneum (up to 9.1 micrograms/g of tissue) primarily by diffusion from the vascular system through the dermisepidermis. It also reaches high concentration in sebum (up to 45.1 micrograms/ml) after several days and continue to concentrate in sebum for up to two days after discontinuation of drug. Hair concentration reach levels of 2.6 micrograms/g of tissue indicating high drug levels in and around the hair follicle. It is not found in sweat. Plasma levels range between 0.1 and 1.0 micrograms/ml. There is a tenfold accumulation of drug in stratum corneum by day 2. Elimination of drug from tissue occurs with a half-life of 4 to 5 days and with the potential for drug levels above fungicidal concentrations for dermatophytes for more than 3 weeks. The tissue pharmacokinetic profile of terbinafine is similar to that of another lipophilic drug, itraconazole, but is very different from ketoconazole and griseofulvin. Higher levels of terbinafine are achieved than of either of the imidazoles and remain longer than griseofulvin.

Adolescent↗
PubMed1991

Effect of topical corticosteroids on human sebum production assessed by two different methods.

Topical corticosteroids are widely used in cutaneous diseases. Although their mode of action on different skin compartments has been documented, little is known about their effects on the human sebaceous gland. We investigated the effects of two corticosteroids of differing potency on the excretion of sebum by means of two validated techniques: the Sebutape and the Lipometre. This study was conducted on the forehead skin of normal healthy subjects. The results obtained with both techniques correlated well. The application of both corticosteroids during a 4-week period led to a significant decrease in sebum excretion. This decrease was more pronounced with the more potent corticosteroid (Dermovate). In the light of these findings, it is likely that topical corticosteroids exert an anti-proliferative action upon the sebaceous cells in a similar manner to their effect in other skin compartments.

Administration, Cutaneous↗
PubMed1979

Is the excretion of sebum regulated?

The kinetics of sebum excretion on the forehead of volunteers were measured over a period of at least 7 h. The transmission data obtained by the ground glass method were transformed into weight (sebum/cm2). The excretion time function can be described by the equation: w = A . (1 - B . e -C.t). This nonlinear function is typical for modes of excretion in the biological field. Regulation of sebum excretion is probable. Objections against such regulation by feedback were discussed.

Feedback↗
PubMed1978

Sebum composition: a comparison of thin-layer chromatography and infrared reflectance spectroscopy.

Thin-layer chromatography and infrared reflectance spectroscopy were compared as methods for measuring sebum composition. Solutions of varying known concentrations of free fatty acids and triglycerides were analyzed by both methods. Skin surface lipid samples were similarly analyzed. Infrared spectroscopy produced more variable data than thin-layer chromatography with photodensitometry. This was particularly true at low concentrations of free fatty acids. It is concluded that thin-layer chromatography with photodensitometry is a more accurate method for the measurement of sebum composition.

Chromatography, Thin Layer↗
PubMed1979

The effect of topically applied progesterone on sebum excretion rate.

There is evidence that anti-androgens may help in the treatment of acne vulgaris. We therefore performed a double-blind trial to assess the effect of topically applied progesterone on sebum excretion rate. Thirty-eight patients took part in the trial which was for 3 months. The preparation had no effect in males. However, a significant reduction in sebum excretion rate was found in females, the effect being maximal at the end of the second month. There was a significant loss of effect at the end of the third month and this was not related to deterioration of the progesterone preparation.

Acne Vulgaris↗
PubMed1992

Keloids: a study of the immune reaction to sebum.

A controlled study of the "immune reaction to sebum" pathogenesis of keloids was carried out at the University College Hospital, Ibadan, Nigeria; on 22 humans using a homogenate solution of liquid paraffin and vernix caseosa from neonates. The 22 human volunteers comprised two groups, 11 of which were keloid formers and 11 non keloid formers. 0.1cc of sterile liquid paraffin was injected intradermally into the anterior aspect of the left forearm. The mean reaction in keloid formers was 11.55mm while in non keloid formers, it was 8.18mm. Although a higher reaction was demonstrated in this study, in keloid formers, this was found not to be significant (p less than 0.05), thus suggesting that sebum may not be an important factor in the pathogenesis of keloid.

Adolescent↗
PubMed1977

The structure of triglyceride in human sebum.

1) A relatively large quantity of branched chain and odd-carbon-number fatty acids were found in human sebum. 2) These acids were present in each lipid fraction (cholesterol ester, triglyceride and free fatty acid) of sebum. 3) In the triglyceride molecule, these acids were found mainly on the 2-position.

Chemical Phenomena↗