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Thursday, March 1

  1. page Photosensitivity edited ... This image shows a skin reaction to a phototoxic compound {phototox.jpg} ... that DNA is…
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    This image shows a skin reaction to a phototoxic compound
    {phototox.jpg}
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    that DNA isbecomes damaged. The
    This image illustrates the uptake of dopamine into cells and the subsequent formation of a reactive oxygen intermediate which is phototoxic in nature
    {radical.gif}
    (view changes)
    4:34 pm
  2. page Vancomycin Toxicity edited ... Skin Toxicity Red Man Syndrome (RMS): ... in less an than 1 hour. The main symptoms of…
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    Skin Toxicity
    Red Man Syndrome (RMS):
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    in less anthan 1 hour.
    The main symptoms of RMS, like the rare angiodema side effect, are caused by histamine release. This is not an IgE induced allergic reaction though, the histamine release is mediated solely through direct interaction with vancomycin or products of vancomycin metabolism within the body. The symptoms of RMS usually appear in the patient 4-10 minutes after the slow infusion has begun but can appear even after the infusion has ended.
    The drug induced histamine release is mediated via an increase in IP3 (inositol triphosphate) and hence release of intracellular calcium in mast cells and basophils. When IP3 binds to the IP3 receptor, a calcium channel, and activate it, there is a huge influx of intracellular calcium to mast cells and basophils that contain histamine. The influx of calcium causes the release of the histamine; this causes the erythema and pruritis associated with RMS. The increase in IP3 that is documented through experimentation and research is directly linked to the vancomycin and is thought to be the mechanism through which RMS is related to vancomycin administration.
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    4:17 pm
  3. page Vancomycin Toxicity edited ... Vancomycin is an example of a glycopeptide antibiotic. It works as an antibiotic by inhibiting…
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    Vancomycin is an example of a glycopeptide antibiotic. It works as an antibiotic by inhibiting cell wall synthesis via the mechanism of peptidoglycan inhibition. Peptidoglycan is a key component of the bacterial cell wall and without it, the cell wall is not able to function and lyses; therefore vancomycin is classed as bactericidal. Vancomycin prevents the transglycolysation step in the polymerization of peptidoglycan. In normal peptidoglycan there are two repeating carbohydrate units called NAG (N-acetylglucosamine) and NAM (N-acetylmuramic acid). Transpeptidase is an enzyme that cross links the short peptide chains that are found on NAM to link the NAM/NAG residues; this cross linking process is a process that strengthens peptidoglycan and hence the cell wall of the bacteria. The mechanism of action of vancomycin disrupts this transpeptidisation; this means that the peptidoglycan monomers cannot polymerise and make the long chains required for the formation of the bacterial cell wall. Vancomycin binds specifically to the terminal D-Alanyl-D-Alanine motif on the terminal pentapeptides of the NAG/NAM peptides through forming 5 hydrogen bonds hence blocking the transpeptidase enzyme binding and cross linking adjacent peptides. This disruption of the cell wall polymerisation halts the formation of a fully functional bacterial cell wall which is vital in a living bacteria.
    {vancomycin.jpg}
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    is an aminationanimation showing how
    Adpated from:
    http://pharmacologycorner.com/vancomycin-mechanism-action-animation/
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    11:29 am
  4. page Introduction to Skin Toxicity and Allergies edited ... Skin is the body's first line of defense against external insult; the skin is rountinely expos…
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    Skin is the body's first line of defense against external insult; the skin is rountinely exposed to various chemical agents that may damage the skin layer and overwhelm it's protective function causing chronic or acute reactions/ injury to the skin.
    However this doesn't happen very often as the skin doesn't just repel toxic agents but reacts with them in a variety of complex defensive mechanisms such as thermal and electrolyte regulation to prevent internal or widespread cutaneous damage. The skin absorbs exogenous substances thorough a process called percutaneous absorption and only small amounts of toxins are able to penetrate the stratium corneum layer, however sometimes even a small amount of a potent toxin can cause extensive damage and allergic skin reactions.
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    cross-react with eachothereach other causing skin
    Acne and other chemically triggered skin conditions:
    Some of the common chemicals that we come into contact with everyday, are able to induce skin conditions such as comedogenic acne and even eczema.
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    10:58 am

Wednesday, February 29

  1. page home edited ... Photo Sensitivity Vancomycin Toxicity Botulinum Toxicity Toxin Like our Facebook page fo…
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    Photo Sensitivity
    Vancomycin Toxicity
    Botulinum ToxicityToxin
    Like our Facebook page for useful links to videos and diagrams that helped us when learning about skin toxicity!
    https://www.facebook.com/pages/Toxins-of-the-Skin-PHAR-30030-2012/317018285017546
    (view changes)
    2:47 am
  2. page Botulinum Toxin edited ... https://docs.google.com/spreadsheet/viewform?formkey=dDJaR3prZFZlb2VvNEl4Z3FoNkJ0QkE6MQ Answe…
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    https://docs.google.com/spreadsheet/viewform?formkey=dDJaR3prZFZlb2VvNEl4Z3FoNkJ0QkE6MQ
    Answers:
    https://docs.google.com/spreadsheet/ccc?key=0AnjOj8t9XY4zdDJaR3prZFZlb2VvNEl4Z3FoNkJ0QkE#gid=0https://docs.google.com/spreadsheet/ccc?key=0AnjOj8t9XY4zdDJaR3prZFZlb2VvNEl4Z3FoNkJ0QkE
    References:
    Simpson, L.L., (1989) Botulinum Neurotoxin and Tetanus Toxin, California: Academic Press.
    (view changes)
    2:17 am
  3. page Botulinum Toxin edited Botulinum toxin: A toxin to other parts of the body used therapeutically in skin Introductio…

    Botulinum toxin: A toxin to other parts of the body used therapeutically in skin
    Introduction:
    Botulinnum toxin is a protein and is the most potent toxin known; it is produced by rod shaped bacteria, Clostridium botulinum. It's toxic effects can result in flaccid paralysis along with side effects such as vomitting, nausea and dizziness and can result in death. The bacteria can be found in soil, aquatic sedimants, the gastrointestinal tract of birds, fish and animals and may also be found in or on raw food. There are seven types of the botulinum toxin (A - G) with A, B, E and F being the most prevalent in humans. Three categories of botulism can occur in humans- foodborne botulism, wound botulism and infant botulism. Although toxic, it may also be used as a therapeutic tool in the treatment of neurological and opthalmic disorders caused by unusual and unnecessary muscle contractions as well as cosmetically.
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    2:14 am
  4. page Botulinum Toxin edited ... https://docs.google.com/spreadsheet/viewform?formkey=dDJaR3prZFZlb2VvNEl4Z3FoNkJ0QkE6MQ Answe…
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    https://docs.google.com/spreadsheet/viewform?formkey=dDJaR3prZFZlb2VvNEl4Z3FoNkJ0QkE6MQ
    Answers:
    https://docs.google.com/spreadsheet/gform?key=0AnjOj8t9XY4zdDJaR3prZFZlb2VvNEl4Z3FoNkJ0QkE&gridId=0#charthttps://docs.google.com/spreadsheet/ccc?key=0AnjOj8t9XY4zdDJaR3prZFZlb2VvNEl4Z3FoNkJ0QkE#gid=0
    References:
    Simpson, L.L., (1989) Botulinum Neurotoxin and Tetanus Toxin, California: Academic Press.
    (view changes)
    2:12 am

Tuesday, February 28

  1. page Botulinum Toxin edited Botulinum toxin: A toxin to other parts of the body used therapeutically in skin Introduction:…

    Botulinum toxin: A toxin to other parts of the body used therapeutically in skin
    Introduction:
    Botulinnum toxin is a protein and is the
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    potent toxin known andknown; it is produced by the rod shaped
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    being the mosstmost prevalent in
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    unnecessary muscle contractions.contractions as well as cosmetically.
    Structure:
    Botulinum toxin is a protein produced by the bacteria, Clostridium botulinum. It exists in bacteria as a single-chain protein until it undergoes post synaptic cleavage by protease endogenous or exogenous enzyme. This cleavage occurs between two cysteine residues (a disulphide bridge). This results in neurotoxin activation and the protein is divided into two separate chains- a light chain and a heavy chain. The light chain is half the size of the heavy chain and contains a zinc binding motif. This motif consists of two histidine residues, a glutamate residue and a water molecule. The zinc binding motif is a zinc dependent endopeptidase that works by cleaving peptide bonds of amino acids that are found inside a molecule. The heavy chain consists of a C–terminal that attaches to the surface of target cells and an N-terminal that is involved in the translocation of the light chains across membranes.
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    VAMP, SNAP-25 and syntaxin are SNARE proteins that are targeted by the toxin. The zinc dependent endopeptidase cleaves their peptide bonds and this results in proteolysis. This degradation prevents vesicle fusion by exocytosis which is promoted by the SNARE proteins. These proteins are only able to be cleaved by the zinc dependent endopeptidase before the SNARE proteins are formed.
    Flaccid Paralysis:
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    wrinkle on the skin; denervation occurs and causes the paralysis which gives the smooth appearance to the skin.
    {http://upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Botulism1and2.JPG/230px-Botulism1and2.JPG} Image 2: Flaccid paralysis and ptosis.
    Symptoms:
    (view changes)
    5:30 pm

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