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Preliminary assessment of selected methacrylic acid--acrylic acid copolymers as factors buffering triethanolamine interacting with artificial skin sebum.

To allow cleaning of sebum ducts for acne prophylaxis the authors suggest use of triethanolamine buffered with anionic polymers of acrylic and methacrylic acid. In these preliminary researches addition of Eudragit L-100, Eudragit L-100-55 or Eudragit S-100 implicates decrease of pH of 1.49% triethahnolamine solution from 10.06 even to 7.20. Triethanolamine penetrates into the artificial skin sebum, gains hydrophylic properties, and reacted sebum increase in volume allowing mechanical remove of lipid bed. The highest triethanolamine penetration and the highest volume increase were observed after application of Eudragit S-100 complexes. Eudragit L-100 and L-100-55 proved milder action. These complexes may be applied for further examinations on acne prevention.

Acrylic Resins↗

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↗

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↗

Sebum production is increased in Behçet's syndrome and even more so in rheumatoid arthritis.

Sebum production is under hormonal control. We had shown that male sex is associated with more severe disease in Behçet's syndrome and the acneiform skin lesion of this disorder is not different from ordinary acne, an androgen-dependent lesion. Sebum excretion rate was higher in patients with Behçet's syndrome than in healthy controls, children and patients with ankylosing spondylitis. On the other hand, patients with rheumatoid arthritis had high levels of sebum excretion rate comparable to those found in patients with acne vulgaris. These suggest the presence of a sebotrophic hormone and/or other hormonal effects in Behçet's syndrome and rheumatoid arthritis.

Acne Vulgaris↗

The effect of zinc on the sebum secretion rate.

In accordance with a randomized double-blind experimental design, capsules of zinc sulfate, 440 mg total daily dose, and lactose placebo were administered orally to 10 normal Caucasian males for 3 weeks. Sebum secretion rates and serum zinc levels were determined prior to and following treatment. There was a statistically significant change in the before and after mean sebum secretion rates of the zinc group when compared with those of the placebo group (p less than 0.028). The results of this preliminary study indicate that supplemental zinc sulfate may reduce the quantity of skin-surface sebum. Further investigation is warranted.

Administration, Oral↗

5% Aluminium chloride hexahydrate and sebum excretion rate.

The present study was designed to assess whether 5% aluminium chloride hexahydrate in absolute alcohol exerted any effect on sebaceous gland excretory activity. Eleven acne patients controlled with long-term antibiotics applied active and placebo solutions in a double-blind trial. The sebum excretion rate was measured on two control visits and thereafter at fortnightly intervals for a further 6 weeks. Patients preferred the 'active' solution, many claiming increased dryness of their skin. However, neither the 'active' nor 'placebo' solution had a significant demonstrable effect on sebum excretion rate. The beneficial effect of topical aluminium chloride hexahydrate is therefore assumed to be due to factors other than an alteration in sebum excretion.

Acne Vulgaris↗

Sebum excretion rates in mothers and neonates.

As neonates have a high sebum production compared with 6-month-old babies, we wished to investigate the relationship of sebum production in mother and neonate. The sebum excretion rate (SER) was therefore measured in 10 mothers prenatally, and in each mother and baby as soon after birth as possible, and again 5-12 weeks postnatally. There was a significant correlation between the maternal and neonatal SER perinatally. The perinatal SER in the babies was markedly higher than the postnatal sample. These observations suggest an important role for the maternal hormonal environment on the infant sebaceous glands. There is animal evidence which suggests that the endocrine environment of the neonate influences the sebaceous gland development in puberty, but it is not known whether babies with a high SER are more prone to seborrhoea and acne in later life.

Acne Vulgaris↗

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↗

Mechanisms of sebum production and delivery in man.

Utilizing a solvent extraction system and colorimetric analysis, surface lipid levels were determined on the forehead. To understand the mechanisms involved in the sebaceous gland apparatus, repeated sampling at varying timed intervals were made. The data suggest that frequent surface samplings produce higher rates of lipid replacement. The increasing lipid replacement rates seen with sampling intervals of greater frequency do not follow a linear pattern. Also, lipid replacement rates show a gradual decline with time. This data suggest the existence of a multifunctional sebaceous apparatus involved in sebum production (a rate function), sebum storage (a volume function) and surface delivery (a rate function).

Female↗

Steroid hormone receptors and their relevance for sebum production in the sebaceous gland ear model of the Syrian hamster.

We determined the capacity of steroid hormone receptors in the sebaceous glands of intact nontreated, castrated, with testosterone substituted castrated male, intact female, and intact with testosterone substituted female animals using the animal ear model of the Syrian hamster. The steroid hormone binding capacity was compared with the sebaceous gland areas and sebogenesis. Intact male animals showed large sebaceous follicles, a high sebogenesis rate, and high capacity for sexual hormone binding proteins. In castrated males, the sebaceous gland areas and sebogenesis were both diminished, and androgen and estrogen receptors were decreased. When the castrated males were substituted with testosterone propionate, the sebaceous glands showed large volumes, high sebum production, and androgen binding activity again. In female animals having small sebaceous follicles and a low rate of sebogenesis, testosterone propionate enlarged the sebaceous glands and increased sebogenesis and the capacity of androgen binding. One can conclude from these data that testosterone is not only the main hormone for sebum production but also induces the synthesis of its own receptor.

Animals↗

Patterns of follicular sebum excretion rate during lifetime.

Using the sebum-absorbent tape technique, we have disclosed five different patterns of follicular sebum excretion rate (SER). These are the infantile, pubertal, acne, adult and aging patterns, distinguished by different densities of active sebaceous follicles, by distinct levels of follicular SER and by the relative stability in time of the overall SER.

Acne Vulgaris↗

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↗

The effect of environmental temperature on sebum composition of tropical and temperate breeds of cattle.

This study compared to effect of environmental temperature on sebum composition in 2 breeds of cattle, British (SH) and Brahman (GB), which differ in their abilities to tolerate heat. By long-term exposure of both breeds to environmental temperatures of 24 C and 32 C and the more heat-tolerant GB breed to 38 C, it was possible to make breed comparisons at (a) different body temperatures, i.e., when all animals were exposed to the same environmental temperature, and (b), at the same body temperature, i.e., when the 2 breeds were exposed to different ambient temperatures. The composition of sebum excreted to saturation level on the skin surface was determined. At the same body temperatures, the amounts of fatty acids in each lipid class were higher in GB than in SH animals except during hyperthermia when the amounts of triglyceride fatty acids were similar in both breeds. The total amounts of individual fatty acids except 14:1, 16:1, 20:0 and 14:OH were higher in both breeds at 32 C than at 24 C. The GB cattle excreted more essential fatty acids (EFA) than the SH cattle at 24 C and at 32 C. There was a significant genotype by environment interaction in the amount of EFA excreted in triglyceride decreased whereas the amount excreted in wax esters increased with rising body temperature.

Animals↗

Lack of influence of testosterone on sebum output and composition in bovines.

Experiments were conducted to determine if testosterone influences sebum output (SO) and composition (SC) in different genotypes of cattle. There were significant breed differences in plasma testosterone levels and SO but no relationship was established between the two variables. Castration of neonatal and adult bulls did not affect their subsequent SO or SC. Testosterone treatment of steers failed to change SO. There were no differences in SO or SC between bulls and heifers. The results showed that testosterone does not influence sebum production in bovines and that there was a strong genetic control over SO independent of sex.

Aging↗

The time course of sebum secretion in the guinea-pig.

The time course of sebum secretion in the guinea-pig (Cavia porcellus) was determined by intradermal injection of [1-14C]acetate followed by daily collection of the skin surface lipids at the injection site. The skin surface lipids reached a peak of radioactivity at 5-6 days, indicating that this is the time which elapses between the synthesis of sebum and the surface excretion of the sebaceous lipids. Of the three major skin surface lipid components, the sterol esters (25%) and the wax diesters (25%) showed similar peaks of radioactivity after labelling, but the glycerol ether diesters (30%) showed no radioactivity at any time, suggesting that this lipid is not produced in the skin.

Acetates↗

The treatment of severe cystic acne with 13-cis-retinoic acid. Evaluation of sebum production and the clinical response in a multiple-dose trial.

Fourteen patients with severe, treatment-resistant, nodulocystic acne have been treated with 13-cis-retinoic acid in a double-blind study. The patients were treated with either 0.1, 0.5, or 1.0 mg/kg/day of 13-cis-retinoic acid for 12 weeks. A marked dose-related decrease in sebum production, which was usually evident within 2 weeks of the onset of therapy, was observed in all patients. At a dose of 1.0 mg/kg/day of 13-cis-retinoic acid, sebum production was decreased to about 10% of the pretreatment value. Clinical improvement, as judged by counting the nodulocystic lesions and measuring their greatest diameters, was noted in all three groups. The most common clinical side effects were cheilitis, desquamation of the skin, and pruritus, but the side effects were not severe enough to require interruption of treatment. Laboratory abnormalities during therapy were minimal and also did not necessitate the cessation of therapy.

Acne Vulgaris↗

Changes in long-term sebum production from isotretinoin therapy.

Sebum production has been measured in twenty patients in whom 13-cis-retinoic acid therapy had been discontinued for at least 20 weeks. While sebum production had returned to pretreatment levels by 30 weeks in seven subjects, 30% to 80% reduction in sebaceous gland activity was still present for as long as 80 weeks in eight subjects. Four of these eight patients, who were followed for more than a year, still had marked sebaceous inhibition when last tested. The prolonged remission seen in patients with nodulocystic acne may be related in part to continued sebaceous gland inhibition in some patients, but it obviously is not the only actor responsible for the long-term improvement that is seen.

Acne Vulgaris↗

Sebum, cosmetics, and skin care.

Recent contributions to the understanding of the physiology and biochemistry of sebum production and of the lipids on the skin surface are leading to the development of effective strategies to regulate excessive sebum production and its consequences through the use of cosmetics and skin care products.

Acne Vulgaris↗