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Thread: collagen

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    IMG SURVIVOR's Avatar
    IMG SURVIVOR is offline Moderator 536 points
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    collagen

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    Collagen concisely covered
    COLLAGEN:
    C-terminal propeptide (procollagen)/ Covalent Cross links/ C vitamin/ Connective tissue/ Cartilage/ Chondroblasts/ Copper Cofactor (Covalent Cross linking)
    Outside the cell is where collagen normally functions/ Osteoblasts/ Osteogenesis imperfecta
    Lysyl hydroxylase/ Lysyl oxidase (oxidatively deaminates lysyl and hydroxylysyl residues to form collagen cross links, last biosynthesis step)
    Long triple helical fibers/ Ligaments
    Alpha chains/ Attached by H bonds form triple helix/ Ascorbate for hydroxylation of lysyl and prolyl residues of pro-Alpha chains (postranslational modification)
    Gly in every third position/ Glycosylation of hydroxyl group of hydroxylysine with Glucose and Galactose; GOlgi allows procollagen to GO outside of cell
    Extracellular matrix/ Eye (cornea, sclera)/ Ehlers-Danlos Syndrome
    N-terminal propeptide (procollagen)/ Nonhelical terminal extensions
    · Note: Procollagen LEAVEs the cell to be cLEAVEd by procollagen peptidase
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    why even bother with the obvious. Just know where you are need it and where you can help the most.

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    md90's Avatar
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    question:
    A known patient arrives to your clinic; you know that this person has scurvy... what are the two amino acids involved? And what is the mechanism in scurvy?
    "SLAM-DUNK THE STEPS"

    “Peace, it does not mean to be in a place where there is no noise, no trouble, or no hard work…..it means to be in the midst of those things and still be calm in your
    heart.”

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    IMG SURVIVOR's Avatar
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    lisyne is one
    Moderator: USMLE AND Residency Forums.

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    why even bother with the obvious. Just know where you are need it and where you can help the most.

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    md90's Avatar
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    Quote Originally Posted by IMG SURVIVOR View Post
    lisyne is one
    lysine and proline.. there is weak tensile strength; not being able to cross-link (bridge)..
    "SLAM-DUNK THE STEPS"

    “Peace, it does not mean to be in a place where there is no noise, no trouble, or no hard work…..it means to be in the midst of those things and still be calm in your
    heart.”

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    ZWobble is offline Junior Member 510 points
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    Scurvy results from a deficiency of vitamin C (asorbic acid). Asorbic acid is needed for hydroxylation of lysine and proline residues during collagen synthesis.

    Vitamin C deficiency can be caused by diets lacking fruits and vegetables.

    On the boards it commonly presents with a patient on a "tea and toast diet". Because they have deficient collagen synthesis they can present with bleeding (ecchymoses, hemarthroses, bleeding gums and perfollicular hemmorhages) --- so dont confuse with vitamin k deficiency!

    So tell me, what does vitamin c excess cause?

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    Quote Originally Posted by ZWobble View Post
    Scurvy results from a deficiency of vitamin C (asorbic acid). Asorbic acid is needed for hydroxylation of lysine and proline residues during collagen synthesis.

    Vitamin C deficiency can be caused by diets lacking fruits and vegetables.

    On the boards it commonly presents with a patient on a "tea and toast diet". Because they have deficient collagen synthesis they can present with bleeding (ecchymoses, hemarthroses, bleeding gums and perfollicular hemmorhages) --- so dont confuse with vitamin k deficiency!

    So tell me, what does vitamin c excess cause?
    vitamin C excess.. cause increased uric acid leading to kidney stones

    so how can you differentiate between Vitamins C and K? remember that vitamin K has to do with clotting factors, and it is the antidote for warfarin.. so if there is a deficiency of Vitamin K.. there will be a prolonged PT...
    "SLAM-DUNK THE STEPS"

    “Peace, it does not mean to be in a place where there is no noise, no trouble, or no hard work…..it means to be in the midst of those things and still be calm in your
    heart.”

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