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PubMedDate not supplied

Palmitoleic acid isomer (C16:1delta6) in human skin sebum is effective against gram-positive bacteria.

The percent lipid composition of pooled human sebum analyzed by thin-layer chromatography was: ceramides (13%), fatty acid (47%), cholesterol (7%), cholesterol esters (2%), squalene (11%), triglycerides (3%), and wax esters (17%). Total sebum lipids (2- 4 mg/ml), sonicated into bacterial culture medium, caused 4- to 5-fold log reduction in growth of gram-positive bacteria, Staphylococcus aureus, Streptococcus salivarius and the anaerobe Fusobacterium nucleatum, but was ineffective against most gram-negative bacteria. Fractionation of the sebum lipids showed that both saturated and unsaturated fatty acids contained the bulk of the antimicrobial activity. Lauric acid (C12:0) was the most active saturated fatty acid. The unsaturated fatty acid, palmitoleic acid (C16:1delta6, cPA) was both the most predominant monoene and the most active antimicrobial fatty acid. Purified cPA (>99%) yielded typical minimal inhibitory concentration (MIC) values of 10-20 microg/ml against gram-positive bacteria. Organically synthesized cPA isomer gave MIC values comparable to the natural material. Both natural and synthetic cPA were found to be the most active sebum lipid fraction in blocking the adherence of a pathogenic strain of Candida albicans to porcine stratum corneum. Ethanol in combination with cPA exerts a synergistic bactericidal activity against gram-negative pathogenic bacteria, including Pseudomonas aeruginosa, Propionibacterium acnes, Escherichia coli, and several methacillin-resistant strains of S. aureus. Palmitoleic acid may be useful in topical formulations for treatment of secondary gram-positive bacterial infections, as a gram-positive bacteria antimicrobial in wound dressings, and as a natural gram-positive antimicrobial preservative in skin and hair care products.

Animals↗
PubMed2000

Effects of sex steroid deprivation/administration on hair growth and skin sebum production in transsexual males and females.

To investigate androgen effects on the skin pilosebaceous unit, we studied 21 male-to-female transsexuals and 17 female-to-male transsexuals receiving cross-sex hormones. At baseline and after 4, 8, and 12 months, hair growth was evaluated by the Ferriman-Gallwey score; acne by the Leeds classification; hair growth rate, density, and shaft diameter by image analysis; and sebum production by Sebutape. In males, estrogens and antiandrogens reduced plasma testosterone to below 1.0 nmol/L. Though all parameters of hair growth and sebum production declined, facial hair growth continued. After 4 months, the decrease in shaft diameter had reached its maximum and seemed inversely associated with changes in hair growth length and density. In females, testosterone increased hair growth rate and sebum production. After 12 months, hairs on the cheek and abdomen had not yet reached diameters found in males. 5alpha-Androstane-3alpha,17beta-diol glucuronide levels were only weakly associated with hair growth and sebum production. In conclusion, administration of estrogens and antiandrogens affects length and diameter of hairs at different rates. In the virtual absence of androgens, hair growth continues but at a slower rate. In women, after 12 months of androgen administration, hair diameters have not reached values of adult men.

Acne Vulgaris↗
PubMed1997

Sebum and water content in the skin of aged immobilized patients.

In the present study we investigated the sebum content and hydration of the skin in aged immobilized patients. Healthy aged as well as young and aged immobilized patients were evaluated by photometry, using a sebum tester and capacitance meter to detect sebum and hydration, respectively, in various skin areas. Sebum content was significantly higher in the young groups as compared to the aged ones, including those of the immobilized patients. Similar values of water content were observed in the healthy young and aged volunteers. However, surprisingly, a significantly marked decrease was detected in each tested area of the immobilized patients. We may assume that a cascade of events caused by the immobilization status of the patients leads to a significant decrease in water content within the dermis.

Adult↗
PubMed1986

Arotinoid Ro 13-6298 and etretin: two new retinoids inferior to isotretinoin in sebum suppression and acne treatment.

Thirty patients have been treated with either etretin, the main derivative of etretinate, or arotinoid Ro 13-6298, a polyaromatic retinoid, or isotretinoin. Sebum production was measured before and during the treatments. While no change was observed in the patients treated with etretin, a reduction of 33% of the sebum excretion rate was observed for those treated with arotinoid Ro 13-6298 but only after long treatment periods of 20 to 30 weeks. The sebum excretion rate decreased by 92% in the patients treated with isotretinoin. Four patients suffering from severe nodulocystic acne were treated with arotinoid Ro 13-6298 for 2-5 months without improvement. Substantial improvement, however, resulted after a subsequent treatment with isotretinoin; sebum production decreased markedly as well. This study suggests that neither etretin nor arotinoid Ro 13-6298 will replace isotretinoin in the treatment of severe nodulocystic acne.

Acitretin↗
PubMed1989

Changes in sebum secretion and the sebaceous gland.

New data have shown that sebum secretion is highest in young adults and then declines steadily throughout life in both men and women. This parallels the decline in androgen levels, but this cannot be the sole factor because there is so much overlap in sebaceous gland activity between men and women. The increased occurrence of dry skin in the elderly has been shown to be unrelated to the sebum secretion rate. This is not unexpected, as children, with even less sebum, rarely have this problem. Seborrheic dermatitis, which is also much more common in the elderly, is also unrelated to sebum secretion rate.

Aging↗
PubMed1986

Changes in sebum secretion and the sebaceous gland.

New data have shown that sebum secretion is highest in young adults and then declines steadily throughout life in both men and women. This parallels the decline in androgen levels, but this cannot be the sole factor because there is so much overlap in sebaceous gland activity between men and women. The increased occurrence of dry skin in the elderly has been shown to be unrelated to the sebum secretion rate. This is not unexpected, as children, with even less sebum, rarely have this problem. Seborrheic dermatitis, which is also much more common in the elderly, is also unrelated to sebum secretion rate.

Adolescent↗
PubMed1982

Studies on the critical period of neonatal life for the differentiation of sebum secretion in rats.

Sprague-Dawley rats were castrated at the age of 1, 3, 5, 10 or 21 days. A control group of male and female rats were also included for comparison. The secretion rate of sebum was assessed from the amount of skin-surface lipids that could be extracted by acetone and which had been produced during 2 days. Sebum production increased with age, particularly in male rats. Castration of male rats at the age of 1, 3, 5, or 10 days showed no differences from female rats in sebum secretion when measured at the age of 80 days. On the other hand, male rats that had been castrated at the age of 21 days secreted significantly more sebum than female rats.

Animals↗
PubMed1994

A prospective study of the effect of isotretinoin on the follicular reservoir and sustainable sebum excretion rate in patients with acne.

BACKGROUND AND DESIGN: A prospective study of 30 patients with moderate to severe acne was performed. The follicular reservoir and sustainable sebum excretion rates were measured before and after a 4-month course of isotretinoin at a dose of 1 mg/kg per day. RESULTS: The follicular reservoir and sustainable sebum excretion rates were profoundly reduced at the end of the course of isotretinoin (79% and 83%, respectively) and remained significantly suppressed at 1 year following therapy (43% and 36%, respectively). Those patients who relapsed clinically at 1 year after treatment had a significantly higher follicular reservoir rate. CONCLUSIONS: These data support the concept that up to 1 year after therapy, there is a reduction in the sebum secretion rate accompanying the remission of acne. This suppressed sebum secretion may modulate the microenvironment of the pilosebaceous canal through an effect on the follicular reservoir.

Acne Vulgaris↗
PubMed2000

Degreasing method for the seborrheic areas with respect to regaining sebum excretion rate to casual level.

BACKGROUND/AIMS: Sebum excreted from the seborrheic glands keeps the skin surface subtle and moist. Before determining the activity of seborrheic glands, the skin surface must be degreased to remove contamination but without provoking sebum excretion. The purpose of this study was to set up a standardised degreasing procedure for various seborrheic areas in different skin types. The method will take day-to-day variations into account with respect to the kinetics of refatting. METHODS: The Sebumeter(R) from Courage+Khazaka is used to quantify the sebum excretion. Day-to-day variations were measured on the forehead in groups of 12 volunteers on 2 consecutive days. The degreasing procedure was investigated by individual cleaning with alcohol compared to washing with a mild detergent followed by wipes with alcohol on the forehead. The degree of refatting was monitored until 3 h after defatting on seborrheic areas: the forehead, cheek, nose, chin and upper back. RESULTS: There was no statistical significant difference in the variation from day to day (P<0.05), although a change in the individual skin types was observed. An individual difference in the number of alcoholic wipes needed to degrease the forehead was seen. Washing followed by several repetitions of alcoholic wipes was not sufficient for the forehead, chin and nose (P>0.05). For the cheek and upper back, it was sufficient to wash with soap (P<0.05). The time from degreasing the skin until the sebum output reached the casual level was 2 h (P>0.05). The area under the curve (AUC) indicates that individual skin types return to casual level after defatting. CONCLUSION: There was no statistically significant day-to-day variation using the Sebumeter(R). We ended up with different degreasing procedures in different seborrheic areas. Washing gently with a detergent solution and then performing three wipes with alcohol was optimal for degreasing the forehead, nose and chin. For the cheek and upper back, it was sufficient to use a mild soap. Casual level was reached after 2 h in all seborrheic areas, irrespective of level of oiliness.

Journal Article↗
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↗
PubMed1988

Effect of an orally administered arotinoid, Ro 15-0778, on sebum production in man.

1,2,3,4-Tetrahydro-1,1,4,4-tetramethyl-y-[(E)-alpha-methylstyryl]- naphthalene (Ro 15-0778), a potent inhibitor of sebaceous gland activity in several animal models has been administered to male volunteers in dosages of 1, 2, 3, and 6 mg/kg/day and 2 g/day for 8 weeks. Sebum production was measured before treatment and after 4 and 8 weeks of therapy. At the dosage levels of 1, 2, 3, and 6 mg/kg/day there was no decrease in sebum secretion. With the dosage of 2 g/day, a significant decrease in sebum secretion was seen after 8 weeks of treatment with Ro 15-0778.

Acne Vulgaris↗
PubMed1982

Effect of 13-cis-retinoic acid on sebum production and Propionibacterium acnes in severe nodulocystic acne.

Ten patients treated with 13-cis-retinoic acid demonstrated a 70% reduction in sebum excretion on the forehead and cheek. An average reduction of 66% occurred in the 1st month, slowly increased to 70% by the 3rd month, and then remained constant for the final 2 months of therapy. Concomitant with this sebum excretion reduction was a fall in the number of Propionibacterium acnes recovered from both sites. Pretreatment values of 10(4) P. acnes per square centimeter (cm2) fell to 10(3) per cm2 after 1 month and 10(2) after 9 months of therapy. P. acnes was not recovered from six of the ten subjects in the following 3 months and only at levels of 10(2) per cm2 in three subjects. One subject's P. acnes level was reduced to only 10(4) per cm2. Following discontinuation of therapy, sebum levels and P. acnes counts showed a trend to recover to pretreatment levels within 2 months.

Acne Vulgaris↗
PubMed1984

The effect of environmental temperature on the excretion time of sebum in different genotypes of cattle.

The sebum excretion times (SET) were studied in two breeds of cattle, Bos taurus (SH) and the more heat tolerant B. indicus (GB). Both breeds were maintained in thermoneutral (24 degrees C) and hot (32 degrees C) environments. SET was defined as the time between synthesis and release of sebum on to the skin surface. The SET was 7 days in SH and 6 days in GB animals at 24 degrees C but was a day earlier at 32 degrees C for each breed. The changing SET with environmental temperature was associated with an increased rate of synthesis of sebum with increased body temperature.

Acetates↗
PubMed2005

Optimization of microwave-assisted extraction followed by solid phase micro extraction and gas chromatography-mass spectrometry detection for the assay of some semi volatile organic pollutants in sebum.

Methodology using MAE/SPME/GC-MS is being pursued for the analysis of organic pollutants in sebum. The microwave-assisted extraction (MAE) of standards of semi volatile organic pollutants from sebum was optimized. All compounds were extracted from sebum with recoveries analyzed by GC/MS ranging from 94% to 100% under the optimum MAE conditions: 10mL acetone-hexane (2:1), 60 degrees C, and 10 min microwave heating. To improve the detection limits a SPME procedure was optimized. Linearity ranged from 0.70 ppb to 25 ppb. R.S.D. were in the range of 1-23% for the SPME step. Preliminary real samples were analyzed and a range of compounds was detected. The optimized MAE/SPME/GC-MS methodology promises to be useful for different applications.

Environmental Pollutants↗
PubMed2000

Behaviour of Glossina morsitans morsitans Westwood (Diptera: Glossinidae) on waterbuck Kobus defassa Ruppel and feeding membranes smeared with waterbuck sebum indicates the presence of allomones.

The behavioural responses of caged individual teneral Glossina morsitans morsitans on waterbuck and ox and on feeding membranes with and without smears of different doses of waterbuck sebum were compared. No significant difference was found in the initial landing behaviour on the two animals, nor on treated and control parts of the membrane. However, the subsequent behaviours of the flies were significantly different. Whereas none of the flies that landed on the ox showed any escape behaviour, more than a third of those that initially landed on waterbuck departed before probing. Similar results were obtained on feeding membranes treated in part with 1.0 or 1.4 mg cm(-2) of waterbuck sebum. Moreover, flies that landed on waterbuck or its sebum changed probing sites more often and probed significantly longer. The proportions that initiated feeding during the 10 min observation period were also significantly less. Our results suggest the presence of both volatile and non-volatile allomones on waterbuck which would account for low numbers of flies found attracted to and feeding on waterbuck in the wild.

Animals↗
PubMed1999

Recent trend of polychlorinated dibenzo-p-dioxins and their related compounds in the blood and sebum of Yusho and Yu Cheng patients.

We investigated the levels of polychlorinated dibenzo-p-dioxins (PCDDs) and their related compounds in blood and sebum from Yusho and Yu-Cheng patients and findings compared with those of normal subjects. Concentrations of these compounds in blood and sebum still were obviously reflected the chemical concentration in the causal rice oil ingested 17 or 26 years since the outbreak. In addition, sebum form the body surface was the most useful sample for monitoring the amount of chemicals contaminating the human body.

Adult↗
PubMed2003

Preliminary assessment of alginic acid as a factor buffering triethanolamine interacting with artificial skin sebum.

Triethanolamine is an ethanolamine used as counter-ion for fatty acid soaps. Interaction between triethanolamine and free fatty acids is suggested to be useful for cleansing sebaceous follicles in acne prevention. This study describes the preliminary assessment of alginic acid as a factor buffering triethanolamine interacting with stearic acid--a compound of artificial skin sebum. Penetration of triethanolamine into artificial sebum, induced by the above mentioned interaction, was measured using a specific optical method. The values of the penetration depth amounted to 0.07-5.74 mm. pH values were measured. The value of pH is reduced from 10.06 for pure 1.49% (w/w) aqueous triethanolamine solution to 6.61 with the increase of the alginic acid to triethanolamine ratio in the preparations. The data of this in vitro research will support further study on other anionic polymers as factors buffering ethanolamines penetrating artificial skin sebum.

Alginates↗