Tag Archives | uv-exposure

Australia-forbids-sunbeds

The Sunbed Ban in Australia – When SunSmart Gets Stupid

The sunbed ban in Australia makes the SunSmart campaign become stupid. What’s going on down under in the country of Oz? The Aussies are banning sunbeds. Not only age-restrictions but total ban on tanning beds. Only Brazil has until now adopted laws which forbid indoor tanning. The reasons for the sunbed ban in Australia are, […]

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The Best From The Tanning Blog 2013

The Best From The Tanning Blog 2013

Get The Best From The Tanning Blog Here! Now you can get, directly through a link in your inbox, a PDF-document with the best from The Tanning Blog 2013. Just fill in your name and email in the form below and click the “YES” button. There is a total of 26 pages in the document. You […]

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use of sunbeds can reduce risk of skin cancer

Regular use of sunbeds can reduce the risk of skin cancer.

Can you really reduce the risk of melanoma and non-melanoma skin cancers with the help of sunbeds? It sounds like an idea invented by the indoor tanning industry but is in reality a conclusion possible to draw after a couple of recent studies about sun-exposure and melanoma/non-melanoma skin cancers In a report, “Occupational sun exposure […]

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sunlight-the-best-medicine

Is Sunlight The Best Medicine?

Given the recent results from Vitamin D research, could it be so that sunlight is the best medicine there is? What if a “WONDER-DRUG” existed, that would: ! Reduce the risk of getting more than 60 different kinds of diseases among them: Most kind of cancers (inclusive skin-cancers) Heart Disease Multiple Sclerosis (MS) Type 1 Diabetes […]

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Stratum Corneum

Stratum corneum
Epidermal layers.png
Histologic image of human epidermis
Latin stratum corneum epidermidis
Gray's subject #234 1064

The stratum corneum (Latin for ‘horned layer') is the outermost layer of the epidermis, consisting of dead cells (corneocytes) that lack nuclei and organelles.

The purpose of the stratum corneum is to form a barrier to protect underlying tissue from infection, dehydration, chemicals and mechanical stress. Desquamation, the process of cell shedding from the surface of the stratum corneum, balances proliferating keratinocytes that form in the stratum basale. These cells migrate through the epidermis towards the surface in a journey that takes approximately fourteen days.[1]

Contents

Function

During cornification, the process whereby living keratinocytes are transformed into non-living corneocytes, the cell membrane is replaced by a layer of ceramides which become covalently linked to an envelope of structural proteins (the cornified envelope).[1][2] This complex surrounds cells in the stratum corneum and contributes to the skin's barrier function. Corneodesmosomes (modified desmosomes) facilitate cellular adhesion by linking adjacent cells within this epidermal layer. These complexes are degraded by proteases, eventually permitting cells to be shed at the surface. Desquamation and formation of the cornified envelope are both required for the maintenance of skin homeostasis. A failure to correctly regulate these processes leads to the development of skin disorders.[1]

Cells of the stratum corneum contain a dense network of keratin, a protein that helps keep the skin hydrated by preventing water evaporation. These cells can also absorb water, further aiding in hydration. In addition, this layer is responsible for the “spring back” or stretchy properties of skin. A weak glutenous protein bond pulls the skin back to its natural shape.

The thickness of the stratum corneum varies throughout the body. In the palms of the hands and the soles of the feet this layer is typically thicker, since these regions require additional protection in order to grasp objects and avoid injury. In general, the stratum corneum contains 15 to 20 layers of dead cells. The stratum corneum has a thickness between 10 and 40 μm.

In reptiles, the stratum corneum is permanent, and is replaced only during times of rapid growth, in a process called ecdysis or moulting. This is conferred by the presence of beta-keratin, which provides a much more rigid skin layer.

In the human forearm, about 1300 cells per cm2 per hour are shed.[citation needed]

Skin disease

An inability to correctly maintain the skin barrier function due to the dysregulation of epidermal components can lead to skin disorders. For example, a failure to modulate the activity of kallikreins via the disruption of the protease inhibitor LEKTI causes the debilitating disorder Netherton syndrome.[3]

Additional images

See also

References

  1. ^ a b c Ovaere P, Lippens S, Vandenabeele P, Declercq W. (2009). “The emerging roles of serine protease cascades in the epidermis”. Trends in Biochemical Sciences 34 (9): 453–463. doi:10.1016/j.tibs.2009.08.001. PMID 19726197.
  2. ^ Haftek M, Callejon S, Sandjeu Y, Padois K, Falson F, Pirot F, Portes P, Demarne F, Jannin V. (2011). “Compartmentalization of the human stratum corneum by persistent tight junction-like structures”. Exp Dermatol 20 (8): 617–21. doi:10.1111/j.1600-0625.2011.01315.x. PMID 21672033.
  3. ^ Descargues P, Deraison C, Bonnart C, Kreft M, Kishibe M, Ishida-Yamamoto A, Elias P, Barrandon Y, Zambruno G, Sonnenberg A, Hovnanian A. (Jan 2005). “Spink5-deficient mice mimic Netherton syndrome through degradation of desmoglein 1 by epidermal protease hyperactivity”. Nat Genet 37 (1): 56–65. doi:10.1038/ng1493. PMID 15619623.

External links

 

This article uses material from the Wikipedia article Stratum Corneum, which is released under the Creative Commons Attribution-Share-Alike License 3.0.

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Sun-tanning

Sun Tanning  sun tanning

Sun tanning or simply tanning is the process whereby sunscreen to skin exposed to the sun, but others use oils to accelerate the tanning process.

Some people tan or sunburn more easily than others. This may be the result of different skin types and natural genetics.

The term “tanning” has a cultural origin, arising from the color tan. Its origin lies in the Western culture of Europe when it became fashionable for young women to seek a less pale complexion (see Cultural history below).

Contents

Tanning process

indirect DNA damage to the skin and the body naturally combats and seeks to repair the damage and protect the skin by creating and releasing further melanin into the skin's cells. With the production of the melanin, the skin color darkens, but the UV-B in sunlight can also cause sunburn. The tanning process can also be created by artificial UV radiation, which can be delivered as UV-A, UV-B, or a combination of both.

There are two different mechanisms involved in production of a tan by UV exposure: Firstly, UV-A radiation creates oxidative stress, which in turn oxidises existing melanin and leads to rapid darkening of the melanin. UV-A may also cause melanin to be redistributed (released from melanocytes where it is already stored), but its total quantity is unchanged. Thus, the effect of UV-A leads to skin darkening, but this is only cosmetic since it does not lead to greatly increased production of melanin and therefore also to little increase in protection against UV-B, or protection against sunburn.[1]

In the second process, triggered primarily by UV-B, there is an increase in production of melanin ([2] The tan that is created by an increased melanogenesis lasts much longer than the one that is caused by oxidation of existing melanin, and is also actually protective against UV skin damage and sunburn, rather than simply cosmetic. However, in order to cause true melanogenesis-tanning by means of UV exposure, some direct DNA photodamage must first be produced, and this requires UV-B exposure (as present in natural sunlight, or sunlamps that produce UV-B).

As noted above, the ultraviolet frequencies responsible for tanning are often divided into the UVB ranges, which will be discussed:

UVA

Ultraviolet A (UVA) radiation is in the wavelength range 320 to 400 nm. It is present more uniformly throughout the day, and throughout the year, than UV-B. UV-A is not blocked by the ozone layer. UV-A causes the release of existing melanin from the reactive oxygen species which damage DNA indirectly. UV-A (see above) apparently induces a cosmetic tan but little extra melanin protection against sun damage, sun burn, or cancer.

UVB

Ultraviolet B (UV-B or UVB) radiation is in the wavelength range 280 to 320 nm. Much of this band is blocked by the Earth's ozone layer, but some penetrates. UV-B does the following:

  • triggers the formation of CPD-DNA damage (direct DNA damage) which in turn induces an increased melanin production[3]
  • is more likely to cause a sunburn than UVA as a result of overexposure. The mechanism for sunburn and increased melanogenesis is identical.[4] Both are caused by the direct DNA damage (formation of CPDs)
  • produces Vitamin D in human skin
  • reduced by virtually all sunscreens in accordance with their SPF
  • is thought, but not proven, to cause the formation of moles and some types of skin cancer
  • causes skin aging (but at a far slower rate than UVA.)[citation needed]
  • stimulates the production of new melanin, which leads to an increase in the dark-coloured pigment within a few days.[5]

Tanning behavior of different skin colors

A person's natural skin color has an impact on their reaction to exposure to the sun. An individual's natural skin color can vary from a dark brown to a nearly colorless pigmentation, which may appear reddish due to the blood in the skin. Though subject to variations, ethnic Europeans generally have lighter skin, while ethnic Africans generally have darker skin. In 1975, Harvard dermatologist [10]

Type Also called Sunburning Tanning behavior von Luschan scale
I Very light or pale, “Celtic” type[11] Often Occasionally 1–5
II Light or light-skinned European[11] Usually Sometimes 6–10
III Light intermediate or dark-skinned European[11] Rarely Usually 11–15
IV Dark intermediate, also “Mediterranean” or “olive skin[11] Rarely Often 16–21
V Dark or “brown” type No Sometimes darkens 22–28
VI Very dark or “black” type No Naturally black-brown skin 29–36

Avoiding tan lines

Example of tan lines caused by a tank top.

The wearing of clothing while tanning results in creation of tan-through swimwear, which uses fabric which is perforated with thousands of micro holes that are nearly invisible to the naked eye, but which let enough sunlight through to produce a line-free tan. Tan-through swimsuits offer SPF protection of about 6, and an application of full-strength sunscreen even to the covered area is recommended.

Because of the potential shade or cool off in water.

Sunless tanning

To avoid exposure to UVB and UVA rays, or in sunless seasons, some people take steps to appear with darkened skin. They may use sunless tanning (also known as self-tanners); stainers which are based on dihydroxyacetone (DHA); bronzers, which are simply dyes; tan accelerators, based on tyrosine and psoralens. Some people use make-up to create a tanned appearance[12] while others may get a tanned appearance by wearing tan colored stockings or pantihose.

Many sunless tanning products are available in the form of creams, gels, lotions, and sprays that are self-applied on the skin. Another option is the use of bronzers which are cosmetics that provide temporary effects. There is also a professional spray-on tanning option or “tanning booths” that is offered by spas, salons, and tanning businesses.[13]

Spray tanning does not mean that a color is sprayed on the body. What is used in the spray tanning process is a colorless chemical which burns the dead citation needed]

The U.S. Food and Drug Administration (FDA) has not approved the use of DHA spray tanning booths because it has not received safety data to support this specific use. DHA is a permitted color additive for cosmetic use restricted to external application. When used in a commercial spray tanning booth, areas such as the eyes, lips or mucous membrane are exposed to the DHA which is a non permitted use of the product.[14]

Tanning controversy

A tanning bed

Overexposure to ultraviolet radiation is known to cause [15] It further states that the risk of developing cancer in the years after exposure is greatest in people under 30 years old. However, recently released FDA data suggests that indoor tanning beds emit 12x more UVA radiation than the sun and has been categorized in the “highest cancer risk” group along with smoking tobacco.

Some researchers have advised that tanning in moderation may be healthier than is commonly believed. Edward Giovannucci, professor of medicine and nutrition at Harvard, states that according to his research, people who have sufficient vitamin D due to UV exposure, and other intake, may prevent 30 deaths for each one caused by skin cancer.Vitamin D for more details.

Tanning agents

Several tanning activators are different forms of [25]

Cultural history

La promenade (1875) by Claude Monet. End of 19th century in the upper social class, people used umbrellas, long sleeves and hats to avoid sun tanning effects.

Throughout history, tanning has gone in and out of fashion. In Western countries before about the 1920s, tanned skin was associated with the lower classes, because they worked outdoors and were exposed to the sun. Women went to great lengths to preserve pallid skin, as a sign of their “refinement”.[26]

Women's outdoor clothing styles were tailored to protect against sun exposure, with full length sleeves, and sunbonnets and other large hats, headscarves, and parasols shielding the head. Women even went as far as to put lead-based cosmetics on their skin to artificially whiten their skin tone.[15] However, when not strictly monitored these cosmetics caused lead poisoning. Achieving a light-skinned appearance was achieved in other ways, including the use of arsenic to whiten skin, and lightening powders. The preference for fair-skin continued until the end of the Victorian era.

By the early 20th century the therapeutic benefits of sunlight began to be recognised.[30]

Shortly thereafter, in the 1920s, [34]

In the 1940s, advertisements started appearing in women’s magazines which encouraged sun bathing. At the same time, swimsuits' skin coverage began decreasing, with the bikini radically changing swimsuit style after it made its appearance in 1946. In the 1950s, many people used baby oil as a method to increase tanning. The first self-tanner came about in the same decade and was known as “Man-Tan,” although it often led to undesirable orange skin.[15] Coppertone, in 1953, marketed their sunscreen by placing a little blond girl and her cocker spaniel tugging on her bathing suit bottoms on the cover of their bottles; this is still the same advertisement used today. In the latter part of the 1950s, silver metallic UV reflectors were common to enhance one’s tan.

In 1962, sunscreen commenced to be SPF rated, although in the US SPF labeling was not standardised by the FDA until 1978. In 1971, Mattel introduced Malibu Barbie, which had tanned skin, sunglasses, and her very own bottle of sun tanning lotion. In 1978, both sunscreen with an SPF 15 rating as well as tanning beds first appeared. Today there are an estimated 50,000 outlets for tanning, whereas in the 1990s there were only around 10,000.[35] The tanning business is a five-billion dollar industry in the United States.[35]

In China, darker skin is still considered by many to be the mark of the lower classes. As recently as 2012, ski masks were becoming popular items to wear at the beach in order to protect the wearer's face from the effects of the sun.[36]

See also

References

  1. ^ https://www.ncbi.nlm.nih.gov/pubmed/20979596 Pigment Cell Melanoma Res. 2011 Feb;24(1):136-47. doi: 10.1111/j.1755-148X.2010.00764.x. Epub 2010 Oct 6. The deceptive nature of UVA tanning versus the modest protective effects of UVB tanning on human skin. Miyamura Y, et al. PMID 20979596
  2. ^ dead link]
  3. ^ 15748643.
  4. http://www.blackwell-synergy.com/doi/abs/10.1111/j.1751-1097.1982.tb04362.x.
  5. ^ “WHO | The known health effects of UV”. Who.int. 2010-12-01. http://www.who.int/uv/faq/uvhealtfac/en/index.html. Retrieved 2012-08-01.
  6. ^ Fitzpatrick TB: Soleil et peau [Sun and skin]. Journal de Médecine Esthétique 1975; 2:33-34
  7. 978-1-4051-4663-0.
  8. ^ SunSmart Homepage : Cancer Research UK. Info.cancerresearchuk.org. Retrieved on 2011-02-27.
  9. ^ Jan Holler, [email protected] “Sample images”. Hauttyp.ch. . Retrieved 2012-08-01.
  10. ^ “Tanning scale”. Fda.gov. 2009-03-10. http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/Tanning/ucm116428.htm. Retrieved 2012-08-01.
  11. ^ hautzone.ch etc.
  12. ^ “Dihydroxyacetone”. http://dermnetnz.org/treatments/dihydroxyacetone.html. Retrieved 2010-07-06.
  13. ^ “Sunless tanning: A safe alternative to sunbathing”. http://www.mayoclinic.com/health/sunless-tanning/SN00037. Retrieved 2010-07-06.
  14. ^ “Sunless Tanners and Bronzers”. http://www.fda.gov/Cosmetics/ProductandIngredientSafety/ProductInformation/ucm134064.htm. Retrieved 2010-07-06.
  15. ^ http://ntp.niehs.nih.gov/index.cfm?objectid=72016262-BDB7-CEBA-FA60E922B18C2540. Retrieved 2009-07-29.
  16. http://www.nejm.org/doi/abs/10.1056/NEJM199711133372003.
  17. http://pubs.rsc.org/en/Content/ArticleHTML/2002/PP/B201230H.
  18. http://archderm.ama-assn.org/cgi/reprint/127/1/99.pdf.
  19. ^ Peeples, Lynne. Study: Frequent tanning-bed use triples melanoma risk. CNN. 27 May 2010.
  20. ^ “Health Effects of Tanning and Vitamin D”. Tanning-advisor.com. http://www.tanning-advisor.com/health-effects-of-tanning.html. Retrieved 2012-08-01.
  21. ^ “Vitamin D, Skin Cancer, and the Dermatologists”. Chetday.com. http://chetday.com/skincancersun.htm. Retrieved 2012-08-01.
  22. ^ Ashwood-Smith MJ. (1979). “Possible cancer hazard associated with 5-methoxypsoralen in suntan preparations”. BMJ 2 (6198): 1144. doi:10.1136/bmj.2.6198.1144-b.
  23. http://www.nature.com/nature/journal/v285/n5764/abs/285407a0.html.
  24. http://carcin.oxfordjournals.org/cgi/content/abstract/2/2/121.
  25. http://www.springerlink.com/content/t6222620211w50w9/.
  26. http://books.google.com/?id=64xpa-rhHLgC&pg=PA151&dq=sun+tan+lower+class&q=. Retrieved 11 September 2009. “Harris investigated the history of the parasol… everywhere ordinary people were forbidden to protect themselves with such devices “pallid skin became a marker of upper-class status”. At the beginning of the 20th Century, in the United States, lighter-skinned people avoided the sun. … Tanned skin was considered lower class.”
  27. ^ The Times. 25 August 1900. p. 1: An advertisement for a ‘German Bath In Scotland' offers ‘For Health and Pleasure…Pure Air and Sun Baths…'.
  28. ^ “Nobel Prize Winners in Medicine – University of Copenhagen”. Healthsciences.ku.dk. . Retrieved 2012-08-01.
  29. ^ The Times. 12 March 1910. p. 12.
  30. Sigmaringen the reporter says: ‘The Castle possesses many delightful terraces which could be adapted for sunbathing.’
  31. ^ [|Hanson, M.D., Peter G.]. “About Face”. The Effects of Aging, Health and Stress on Your Face. FaceMaster. http://www.dnronline.com/news_details.php?AID=11699&CHID=11. Retrieved 11 September 2009.
  32. ^ “Sun and Clouds: The Sun in History”. Magic Bullets – Chemistry vs. Cancer. The Chemical Heritage Foundation . 2001. . Retrieved 11 September 2009. “By the 1920s, the therapeutic effect of the sun was widely promoted, and two well-publicized French personalities gave “tanning” a fashion boost. Coco Chanel, of designer fame, returned to Paris after a cruise on the Duke of Westminster's yacht with a tan that became all the rage. And the natural caramel skin color of singer Josephine Baker made women all over the world try to emulate her skin tone.”
  33. http://books.google.com/?id=RHdeo6uvlfYC&pg=PA2&lpg=PA2&dq=%22Coco+Chanel%22+%22Josephine+Baker%22+tan&q=%22Coco%20Chanel%22%20%22Josephine%20Baker%22%20tan. Retrieved 11 September 2009. “In 1920s France, the caramel-skinned entertainer Josephine Baker became a Parisian idol. Concurrently, fashion designer Coco Chanel was “bronzed” while cruising on a yacht. A winter tan became a symbol of the leisure class and showed you could afford to travel to exotic climates.”
  34. http://books.google.co.uk/books?id=0_3qzO6NTqcC&lpg=PA554&ots=ZGGl5LRqcF&dq=jean%20patou%20huile%20de%20chaldee&pg=PA554#v=onepage&q=%20huile&f=false.
  35. ^ http://www.dnronline.com/news_details.php?AID=11699&CHID=11. Retrieved 11 September 2009. “The tanning industry has grown about 25 percent over the past six years, according to the Indoor Tanning Association. In the United States, about 25,000 free-standing tanning salons employ 160,000 people and generate more than $5 billion in annual revenue, the association said.”
  36. ^ Levin, Dan (3 August 2012). New York Times. http://www.nytimes.com/2012/08/04/world/asia/in-china-sun-protection-can-include-a-mask.html. Retrieved 5 August 2012.

Further reading

External links

This article uses material from the Wikipedia article Sun-tanning, which is released under the Creative Commons Attribution-Share-Alike License 3.0.

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