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Surface Lipids (surface + lipid)

Distribution by Scientific Domains
Medical Sciences66%

Kinds of Surface Lipids

  • skin surface lipid
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    Selected Abstracts

    REMOVAL OF LIPID FROM SURFACES OF ROASTED PEANUTS BY SONICATION AS ASSESSED BY FLUORESCENCE AND SCANNING ELECTRON MICROSCOPY

    JOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2010
    PETER WAMBURA
    ABSTRACT Peanut oil migrates to the outer surface during roasting, where it comes into contact with oxygen, leading to the oxidation reactions. Because of its cleaning effect, power ultrasound (sonication) was used for removing surface lipid of roasted peanuts. Georgia green runner-type peanuts were roasted at 178C for 15 min. Roasted peanuts were subjected to lipid extraction in n-hexane by sonication. Fluorescent and electron scanning micrographs revealed that the surface of sonicated peanuts was free of oil stains, as opposed to that of freshly roasted peanuts. These results showed that power ultrasound could remove the lipids from peanut surfaces very effectively. Details of microstructure of sonicated peanuts as was observed using scanning electron microscope reveal that 10 min sonication was sufficient to extract most of the lipids on the roasted peanut surfaces. Fluorescence and scanning electron microscopy are useful in peanut analysis because they can detect lipids in low concentration. PRACTICAL APPLICATIONS There is increasing interest of quick procedures to examine the surfaces of roasted peanut samples after undergoing treatments, such as removal of lipids. This research demonstrated the significant use of fluorescent and scanning electron microscopes to quickly study the extent of lipid removal from the surface of roasted peanuts after power ultrasound treatment (sonication). [source]

    Frontiers in sebaceous gland biology and pathology

    EXPERIMENTAL DERMATOLOGY, Issue 6 2008
    Christos C. Zouboulis
    Abstract:, The development of experimental models for the in vitro study of human sebaceous gland turned down the theory of a phylogenetic relict and led to the identification of several, unknown or disregarded functions of this organ. Such functions are the production of foetal vernix caseosa, the influence of three-dimensional organization of the skin surface lipids and the integrity of skin barrier and the influence on follicular differentiation. In addition, the sebaceous gland contributes to the transport of fat-soluble antioxidants from and to the skin surface, the natural photoprotection, the pro- and antiinflammatory skin properties and to the innate antimicrobial activity of the skin. It is mainly responsible for skin's independent endocrine function, the hormonally induced skin ageing process, the steroidogenic function of the skin as well as its thermoregulatory and repelling properties and for selective control of the hormonal and xenobiotical actions of the skin. Interestingly, sebocytes, at least in vitro, preserve characteristics of stem-like cells despite their programming for terminal differentiation. This review reports on various sebaceous gland functions, which are currently under investigation, including its role on the hypothalamus,pituitary,adrenal-like axis of the skin, the impact of acetylcholine on sebocyte biology, the activity of ectopeptidases as new targets to regulate sebocyte function, the effects of vitamin D on human sebocytes, the expression of retinoid metabolizing cytochrome P450 enzymes and the possible role of sebum as vehicle of fragrances. These multiple homeostatic functions award the sebaceous gland the role ,brain of the skin' and the most important cutaneous endocrine gland. [source]

    Effect of sunlight exposure and aging on skin surface lipids and urate

    EXPERIMENTAL DERMATOLOGY, Issue 2003
    Nobumasa Hayashi
    Abstract Free fatty acids (FFA), squalene, squalene hydroperoxide, and uric acid in the methanol extracts from human skin surface were measured. Levels of FFA and squalene were significantly lower in the older (83.7 ± 9.4 years) than in the younger (22.2 ± 3.9 years) group. FFA are mostly saturated, and linoleic acid is an exclusive polyunsaturated fatty acid. The composition of linoleic acid decreased in the older group by 40%, suggesting age-dependent loss of oxidatively vulnerable polyunsaturated fatty acid. Even monounsaturated acids such as palmitoleic and oleic acids decreased significantly in the older group. This could be interesting because 2-nonenal is the oxidation product of palmitoleic acid and has been identified as the major aged body odor component. Sunlight exposure for 1.5 h did not change levels of FFA and squalene, or FFA composition. However, squalene hydroperoxide increased by 60-fold, as reported previously, suggesting that hydroperoxide is produced by singlet oxygen. Uric acid increased by two-fold, which may be the adaptive response against photo-oxidative stress because uric acid is a good scavenger of singlet oxygen and oxygen radicals. [source]

    Location-related differences in structure and function of the stratum corneum with special emphasis on those of the facial skin

    INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 6 2008
    H. Tagami
    Synopsis Between the two different kinds of the skin covering the body, the glabrous skin is found only on the palmo-plantar surface because of its rather simple function to protect the underlying living tissue with its remarkably thick stratum corneum (SC) from strong external force and friction. Thus, its barrier function is extremely poor. In contrast, the hair-bearing skin covers almost all over the body surface regardless of the presence of long hair or vellus hair. In regard to its SC, many dermatologists and skin scientists think that it is too thin to show any site-specific differences, because the SC is just present as an efficient barrier membrane to protect our body from desiccation as well as against the invasion by external injurious agents. However, there are remarkable regional differences not only in the living skin tissue but also even in such thin SC reflecting the function of each anatomical location. These differences in the SC have been mostly disclosed with the advent of non-invasive biophysical instruments, particularly the one that enables us to measure transepidermal water loss (TEWL), the parameter of the SC barrier function, and the one that evaluates the hydration state of the skin surface, the parameter of the water-holding capacity of the SC that brings about softness and smoothness to the skin surface. These in vivo instrumental measurements of the SC have disclosed the presence of remarkable differences in the functional properties of the SC particularly between the face and other portions of the body. The SC of the facial skin is thinner, being composed of smaller layers of corneocytes than that of the trunk and limbs. It shows unique functional characteristics to provide hydrated skin surface but relatively poor barrier function, which is similar to that observed in retinoid-treated skin or to that of fresh scar or keloidal scars. Moreover, there even exist unexpected, site-dependent differences in the SC of the facial skin such as the forehead, eyelid, cheek, nose and perioral regions, although each location occupies only a small area. Between these locations, the cheek shows the lowest TEWL in contrast to the perioral region that reveals the highest one. Moreover, these features are not static but change with age particularly between children and adults and maybe also between genders. Among various facial locations, the eyelid skin is distinct from others because its SC is associated with poor skin surface lipids and a thin SC cell layer composed of large corneocytes that brings about high surface hydration state but poor barrier function, whereas the vermillion borders of the lips that are covered by an exposed part of the oral mucosa exhibit remarkably poor barrier function and low hydration state. Future studies aiming at the establishment of the functional mapping in each facial region and in other body regions will shed light on more delicate site-dependent differences, which will provide us important information in planning the strategy to start so called tailor-made skin care for each location of the body. Résumé Entre les deux types différents de peau couvrant le crops, on trouve la peau glabre uniquement sur la surface palmo-plantaire du fait de sa fonction plutôt simple de protection du tissu vivant sous-jacent par un stratum corneum (SC) trés épais vis-à-vis des forces extérieures et de la friction. De ce fait, sa fonction barrière est extrêmement pauvre. Au contraire, la peau velue courve la presque totalité de la surface du crops, que ce soit par la présence de longs cheveux ou de duvet. En ce qui concerne son SC, la plupart des dermatologues et des scientifiques de la peau pensent qu'il est trop mince pour montrer une différence spécifique au site, attendu que le SC est simplement présent en tant que membrane barriére efficace pour protéger notre corps de la dessiccation ainsi que pour lutter contre l'invasion d'agents nuisibles externes. Cependant, il existe des différences importantes entre les sites, non seulement dans la peau vivante, mais également dans ce SC aussi mince, qui révèlent la fonctin de chaque site anatomique. Ces différences dans le SC ont surtout été révélées avec l'apparition d'instruments biophysiques non invasifs, en particulier celui qui nous permet de mesurer la perte transépidermale en eau (TEWL), le paramétre de la fonction barrière du SC et celui qui évalue l'état d'hydratation de la surface de peau, le paramètre de la capacité en rétention de l'eau du SC qui est liéà la souplesse et à la douceur à la surface de peau. Ces mesures instrumentales in vivo du SC ont révélé la présence de différences remarquables entre les propriétés fonctionnelles du SC particulièrement entre le visage et d'autres parties du corps. Le SC de la peau de la face est plus mince, car li est composé de couches plus petites de corneocytes que celui du tronc et des membres. Il montre des caractéristiques fonctionnelles uniques pour permettre l'hydratation de la surface de peau, mais une fonction barrière relativement faible, semblable à celle observée dans la peau traitée avec un rétinoïde ou à celle d'une cicatrice récente ou de cicatrices kéloidales. De plus, il existe des différences sites-dépendantes inattendues dans le SC de la peau de la face comme le front, la paupière, la joue, le nez et les régions périorales, et ce, bien que chaque emplacement occupe seulement un petit secteur. Entre ces divers emplacements, la joue montre le TEWL le plus bas par comparaison avec la région périorale qui montre le plus élevé. De plus, ces caractéristiques ne sont pas fixes, mais changent avec l'âge en particulier entre enfants et adultes et peut-être aussi entre sexes. Entre les diverses régions de la face, la peau de la paupière se distingue parce que son SC est associéà une peau pauvre en lipides de surface constituée par une mince couche de cellule composée de grand cornéocytes qui provoquent un haut état d'hydratation superficiel, mais une faible fonction barrière. A l'inverse les bordures vermillion des lévres recouvertes par une partie exposée de muqueuse orale, possèdent une fonction barrière très faible et un état d'hydratation bas. Les études futures visant àétablir la configuration fonctionnelle de chaque région de la face et d'autres régions du corps mettrons en lumière des différences sites-dépendantes plus subtiles, qui nous fourniront des informations importantes pour planifier la stratégie pour commencer le soin de la peau sur mesure si attendu pour chaque partie du corps. [source]

    Effect of systemic hormonal cyclicity on skin

    INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2006
    N. Muizzuddin
    Fluctuations in estrogen and progesterone during the menstrual cycle can cause changes in body systems other than the reproductive system. We conducted several studies to determine a possible correlation between phases of the menstrual cycle and specific skin properties. Healthy Caucasian women (ages 21,48), who had a typical 26,29 day menstrual cycle, participated in the studies. Measurements of skin barrier strength, dryness, response to lactic acid stinging, skin surface lipids, and microflora were obtained every week for 2 to 3 months. Ultraviolet B (UV-B) susceptibility in terms of minimal erythemal dose was also studied. The skin barrier was the weakest between days 22 and 26 of the cycle. Elevated neuronal response (lactic acid sting) was not observed to vary much with the cycle. Skin was driest between day 1 and day 6, while skin surface lipid secretion appeared to be highest on days 16,20 of the hormonal cycle. The highest microbial count was around days 16,22, and there was a high UV-B susceptibility between days 20 and 28 of the menstrual cycle. [source]

    Skin surface lipids and skin and hair coat condition in dogs fed increased total fat diets containing polyunsaturated fatty acids

    JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 4 2009
    N. A. Kirby
    Summary It is generally believed that diets containing increased amounts of polyunsaturated fatty acids (PUFA) result in improved canine skin and hair coat (SHC). However, the extent to which dietary fat amount and type play a role remains to be systematically investigated. The objective of this study was to investigate the role of both increased dietary fat amount and type on SHC assessments of dogs. Improvements of SHC conditions were investigated after feeding three diets containing increased total dietary fat (i.e. 13% total fat) for 12 weeks in relation to a lower fat acclimation diet (i.e. 9% total fat). The higher fat diets varied in polyunsaturated and saturated fat types and amounts but total fat was kept constant. Skin and hair coat assessments were performed at selected intervals by a trained group of veterinarians and graduate students. In addition, hair lipids were fractionated by thin layer chromatography after extraction of plucked hair samples. Significant improvements were found in hair coat glossiness and softness in all dogs fed the higher fat diets in relation to the acclimation diet. Improvements as a result of fat type were also seen but only at 12 weeks. A parallel finding was a marked increase in hair cholesteryl ester content determined at the end of the study at which time SHC scores were significantly improved. Skin and hair coat condition improvements may thus be related to increased cholesteryl ester deposited on the hair shaft surface when high fat diets are fed. Whereas this finding is preliminary, hair lipid analysis may be a useful, non-invasive technique with which to help assess dietary effects on canine SHC. [source]