Skin Care and Treatments of Melbourne Dermatology - True Broad Spectrum Sunscreen in Action: Protection of Skin Cell Nuclei and Keratinocytes

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True Broad Spectrum Sunscreen in Action: Protection of Skin Cell Nuclei and Keratinocytes

True Broad Spectrum Sunscreen in Action: Protection of Skin Cell Nuclei and Keratinocytes

As the first line of living cells of the epidermis, keratinocytes are the first target hit by the UV range of sun radiation.

The degree of preservation of the epidermis' originality correlates directly to its health and therefore appearance.

The genomic DNA which produced your skin as a baby provided the instructions necessary to produce truly perfect skin.

When a cell is exposed to sunlight, various lesions are produced in its genomic DNA.

UVB mainly induces pyrimidine dimers and pyrimidine pyrimidone photoproducts whereas UVA mostly brings about strand breaks and oxidative damage through endogenous photosensitization.

The excision of these lesions leads to a transient breakage of the DNA backbone, which can be detected by electrophoresis.

Measuring Damage Objectively — The Comet Assay

Healthy, unexposed skin.

The same skin, after one hour's unprotected exposure.

Also named single-cell gel electrophoresis, this is a simple and visual technique for measuring DNA breakage in individual cells.

It has been extensively used to characterize genotoxins and also to analyse DNA repair following photo-toxic effects of UV components of the solar spectrum.

Following exposure to UV solar simulated radiation (SSR) which mimics the UV radiation spectrum of sunlight, cells whose DNA is impaired, i.e. fragmented, exhibit the comet shape.

Comets can be observed as early as 1 hour after irradiation when no significant signs of cell toxicity are detected using the cytotoxic MTT assay.

The amount of comets produced and the extent of trail are measured using image analysis.

Tail moment is recorded based on comet tail length and intensity.

It reflects the size and number of DNA fragments, i.e. the degree of photodamage and repair.

Preventing Damage to Skin Cell Nuclei and Keratinocytes: Biological Protection against 90% of the Signs of Aging.

Unprotected skin.

Inadequately protected skin — similar biological effects as entirely unprotected skin.


Similar: Adequately protected skin (left), and healthy unexposed skin (right).

Effective Anti-Aging and Skin Cancer Prevention:

When the experiment is performed in the presence of a potent broad spectrum UVA filter such as Skinceuticals Daily Sun Defense SPF 20, comet induction is almost totally abrogated, suggesting that genomic DNA is significantly protected, premature aging and skin cancer initiation largely avoided.

The more your the genomic DNA of your skin cells is altered, the less possible it becomes to maintain ideally conditioned skin, due to permanent damage.

Review photoprotection to obtain near perfect protection against 90% of the signs of premature aging.


Mitchell OL, Nguyen TO, Cleaver JH. Non random induction of pyrimidine-pyrimidone (6-4) photoproducts in ultravioletirradiated human chromatin. J BioI Chem 1990; 265: 53535356.

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UVA: The Trojan Horse of Premature Ageing of the Skin : Effects of UVA Exposure : Flaws in The Current Evaluation of SPF (Sun Protection Factor) : True Broad Spectrum Sunscreen in Action: Protection of Skin Cell Nuclei and Keratinocytes : Different Sunscreens provide Different Skin Protection : Jan Marini Antioxidant Daily Face Protectant SPF 30 vs. Skinceuticals Daily Sun Defense SPF 20 : Mature Skin Analysis: Firmness and Elasticity of Healthy vs. Unhealthy Mature Skin : Photoprotection by Topical Trifolium Pratense — Red Clover : Zinc: An Important Antioxidant for Skin : Sunscreen around the Eyes : Photobiologic Basics of Anti-Aging/Skin-Rejuvenating Phototherapy : Anti-Aging Phototherapy by LEDs : Open Pores — Quick Fix Treatment and Lasting Prevention : Darphin Hydraskin: Imperata Cylindrica : Propensity for Vitamin C (as Ascorbic Acid) to Stimulate Acne : Evening Use of Gernetic Adipo/Gasta : Unsafe Flattery: Counterfeit Jan Marini Age Intervention Eyelash : Revised Ingredients: Jan Marini Age Intervention Eyelash : Jan Marini Age Intervention Cream and Serum Ingredient Comparison :

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