Drugs & Cosmetics Flashcards
Melanocytes are
cells that synthesize and eject melanin (pigment)
Blood supply for skin situated
in the dermis ends at the base of the epidermis.
How the skin is given the colour?
Ejected melanin from melanocytes are taken up by surrounding keratinocytes, the epidermal cells.
Exposure to UV light stimulates
melanocytes production and insertion of melanin –> tan.
Psoriasis is
immune reaction that causes hyper-proliferation of keratinocyte at the surface of the skin.
UVA in skins
better able to penetrate the skin, getting to the base of the dermis.
UVB in skins
reaches the epidermis (surface of the skin)
What makes less vulnerable to injury due to UV light?
Melanin does protect to some extent (people with darker skin)
What makes more vulnerable to injury due to UV light>
light skin, particularly people with freckles.
Photoaging is
skin damage by sun.
3 different types of cancers due to sun damage:
Basal cell carcinoma
Melanoma (most lethal type)
Squamous cell carcinoma
Basal cell carcinoma + squamous cell carcinoma = commun skin cancer.
SPF (sun protective factor) mean
indicate how effective the application will be ( ex. if use SPF 15, you can stay outside 15 more minutes before get sun burn.
Problems occurring in acne:
Increase in keratin production (Duck occlusion)
Increase sebum production (block the duck)
Inflammation of sebaceous gland that can rupture
Growth of microorganisms in the duct (release inflammatory mediator)
Blackhead is due to
Abnormal keratinocytes (produce excess amount of keratin) + sebum blocking the duct = becoming oxidized and darkening colour.
What make change a blackhead to a whitehead (pimple)?
If the trapped sebum is closed over, you can get bacteria and leukocytes.
Whitehead is due to
comedo closed with bacterial growth and inflammation with rupture of the follicle (cause the bump)
Retinoid roles:
normalize follicular keratinization
tx for acne:
retinoids benzoyl peroxide isotretinoin sulfur azelaic acid
Retinoid are
Vit A derivatives
Action of Vitamin A
Act as hormones, altering gene expression and play major role in cellular differentiation.
Conversion of Vit A:
Retinol–> retinaldehyde–> retinoid acid
Retinol enter into the cell by
binding to Retinoic binding protein (RBP) after enter unbind.
Retinol to nucleus steps:
Bind to cellular retinol binding protein (CRBP)–> retinol convert to retinoic acid (RA)–> bind to 2e carrier: CRABP–> transport into nucleus. In the nucleus, RA bind to RXR and RAR –> RARE –> gene expression
Two retinoic receptors:
RXR and RAR (dimer) (form heterodimer)
How retinoic acid turns on gene expression?
Dimer RXR and RAR (retinoic receptor) activated and bind to the retinoic acid response element (RARE).
Accutane is
(Isotretinoin) a systemic retinoid. (orally)
Contra-indication:
Female who might possibly get pregnant or is pregnant.
TERATOGEN
Anti-herpes drugs action:
Inhibit viral reproduction mechanism by inhibiting viral DNA polymerase–>cause chain termination.
Antiviral drugs for herpes example:
AcycloGTP
The cuticle is
outside layer of the hair (layer of death cells)
The cortex is
central part of the hair (microfibril and macrofibril)
microfibrils are made up of
protofibrils
anagen is
the growth of the hair phase
catagen is
transition phase
telogen is
the resting phase
the normal cycle of hair follicle:
Anagen–>catagen–>telogen–>hair ejected and falls out.
Cycle starts over.
Growth and shedding(fall out) of hair peaking in:
summer
During pregnancy, hair tend to:
increase (anagen) and shedding tend to decrease.
Pregnancy prevent the follicles from stopping their growth.
After delivery, the hair tend to:
lots of hair to fall out bc extra hair follicles in growth phare are immediately go into shedding phase.
Curliness of hair is based on the chemistry of hair. The structure:
Hydrogen bonds can form between two adjacent hair shaft, or disulfide bonds (stronger).
Getting a ‘‘prem’’:
- breaking disulfide bonds with first chemical
- re-forming disulfide bonds with second chemical in curly structure position of hair
= curly permanet hair!
Male pattern baldness:
thick terminal hairs of the head are replaced by fine, vellus hairs.
Higher level of 5a reductase–> Increase DHT
Why female do not loss all hair with predisposition of balness?
bc less androgen
Product for baldness that do work:
Minoxidil
Finasteride (propecia)
Minoxidil action:
increase size of the follicle
prolongs the growth phase of the hair (prevent transition into small follicles producing vellus hairs)
Finasteride (propecia) action:
Blocks the production of Dihydrotestosterone (DHT)
Finasteride contra-indication:
Pregnant women –> TERATOGEN for male fetuses
Tetracyclines effect on teeth?
Discoloration
Hydroxyapatite is
crystal structure in enamel (surface part of teeth)
Fluoride effect:
enter the hydroxyapatite to change it and produce fluoroapatite.
Fluoroapatite advantages
more resistant to acid in plaque
More resistant to substances released by bacteria
Dental fluorosis is
white spot in theeth, harmless
Gingivitis can be tx with
mouthwash (phenols as active ingredient)
