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136 Cards in this Set
- Front
- Back
Glucosamine method of action?
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substrate for proteoglycan formation (hyaluronate and chondroitin biosynthesis. Chondroitin is the major component of the aggrecan molecule, contnributing t the hydrophilic properties of cartilage and formation of the viscous elastic layer of cartilage). Studies have shown objective slowing of cartilage degenerative process
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relationship of bending stiffness to diameter? (eg pin)
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an increase in bending stiffness is proportional to the radius to the 4th power. ig if one pin has twice the diameter of the other, it also has twice the radius which is 2 to the 4th power, or 16 times more stiff
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how do metastatic tumors attach to the endothelial cell layers of the host bone?
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via Integrin, a cell adhesion molecule (CAM) expressed by tumor cells that allow attachment of the tumor cell to the endothelial layer of the host organ.
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What is E-cadherin?
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CAM (Cell Adhesion Molecule) in tumor cells allowing them to release from primary tumor focus into the bloodstream
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Matrix Metalloproteinases? (MMP)
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used by tumor cells to invade the basement membrane and extracellular matrices
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Vascular Endothelial Growth Factor? (VEGF)?
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expressed by timor cells to induce amngiogenesis into the degraded venous basement membrane and extracellular matrix
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CHemokine ligand 12 (CSCL12)?
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found in stromal cells of normal bone marrow and acts as a homing chemokine to certain tumor cells and promotes the targeting of bone.
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What is the mechanical property descriptive term for the mechanical properties of bone?
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Anisotropic, or that the mechanical properties of bone vary with the orioentation of the specimen within bone because of the orientation of collagen fibers.
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percent insufficiency fractures of large cortical structureal allografts?
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15-30%
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Rickets:
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inadequate mineralization of osteoid and cartilage at growing ends of the bones of children.
"rachitic rosary" - widening of the ribs anteriorly ass'd w nutritional deficiency in children that affects open physes classic findings are widened physes from accumulation of nonmineralized osteoid and cartilage, irregular metaphyses, and loss of definition of the zone of provisional calcification changes seen in bones with greatest growth (tibia, distal femur, distal radius) |
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hyperparathyroidism - cause and consequences?
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accumulation of fibrous tissue in the metaphyses producing lucencies appearing similar to rickets
erosion around the edge of the growth plate punched out lesions and resorption subperiostially |
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Jansen syndrome?
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rounded epiphyses and marked separation of the epiphysis and metaphysis
AD inheritance metaphyseal chondrodysplasia Sclerotic metaphyseal ends are similar to rickets but with maturity spaces fill with eirregular calcification |
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Renal osteodystrophy?
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sclerotic vertebra
"rugger jersey" |
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**Most important adaptation from endurance training?
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increased capillary density!
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Strength training muscle adaptations?
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increased recruitment of motor units
Hyperplasia (formation of additional myofibers) Hypertorphy of indifidual myofibrils |
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***C6-7 HNP most likely distribution of symptoms?
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C7 radiculopathy
pain at forearm and hand numbnes of middle finger weakness triceps weakness finger extensors |
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***C3-4 HNP symptoms?
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C4 radiculopathy
pain post neck and scapula numbness over the clavicle weakness of the head and neck extensors |
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***C4-5 HNP symptoms?
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C5 radiculopathy
pain in the shoulder numbness over the lateral shoulder weakness of the deltoid |
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***C5-6 HNP symptoms?
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C6 radiculopathy
pain at elbow numbness over the thumb and index finger weakness of biceps weakness of wrist extensors |
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***C7-T1 HNP symptoms?
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T1 radiculopathy
pain at the wrist numbness in little and ring fingers Weak finger flexors |
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Lubricin: what is it and what type of lubrication?
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Boundary lubrication. Is mucinous gllycoprotein that is critical to lubrication in joints. Also affect tendon sheaths and pericardium
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Hydrodynamic lubrication?
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when fluid separates two surfaces when one is sliding on another
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Squeeze film lubrication?
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When the layer of fluid is slowly being wqueezed from between two surfaces
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Elastohydrodynamic lubrication?
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Deformation of a surgace moving on another and a thin film separates the surface
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Serotonin syndrome?
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acute adverse drug reaction caused by excess of seotonin activity
produces an array of automonic and somatic effects: abd pain, HA's, diarrhea, clonus |
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Rx serotonin syndrome?
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benzodiazepines to abate symptoms and in severe cases give serotonin antagonists
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def Fatigue?
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gradual accumulation and progression of crack in the material which after many cycles of loading can lead to gross failure
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def Plastic deformatin ?
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if loaded above yield point the object will have some permanent, or plastic, deformation
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def Creep?
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gradual accumulation of permanent (plastic) deformation over time
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def Torsion?
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torque being applied about the long axis of a bone or an implant
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where is 1,25-hydroxycholecalciferon produced and wat does it do?
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Proximal convoluted tubule of the kidneys, and is the active form of Vit D which is the foremost regulator of intestinal calcium absorption
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What will result from decrased phosphate?
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results in hypercalcuria. Appears to be a direct efffect of phosphate to decreased calcum reabsorption in the distal nephron
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what changes happen in articular cartilage with aging?
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dec proteoglycan synthesis
dec water content dec cell numbers dec chondroitin 4-sulfate inc chondroitin 6-sulfate dec total chondroitin sulfate keratin sulfate increases until age 30, then levels off |
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C4 wheelchair needs?
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puffer control
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C5 wheelchair needs?
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hand controls
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C6 wheelchair needs?
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manual wheelchair and sliding board transfers
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C7 wheelchair needs?
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allows independant transfers
(note NO cervical injury routinely allows ambulation wit crutches and leg braces) |
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effect of methylprednisolone administered to spinal injury?
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decrased extent of cord hemorrhage only. No difference in cord edema, or improved clinical outcomes
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how do biphosphonates work?
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antiresorptive agents act by targeting osteoclastice bone resorption
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How does calcitonin work?
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inhibits osteoclastic bone resorption
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How does TNF-a work?:
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inhibits osteoblastic activity and enhances osteoclastic bone resorption
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***How does MRSA develop resistance to penicillinase-stable antibiotics?
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by genetic mutation!
Specifically, genetic mutatin of mecA encoding an altered penicillin binding protein |
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how does resistance to tetracyclines, quinolones, trimethoprim, beta-lactam antibiotics develop?
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Cell wall permeability changes
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how does Salmonella develop antibiotic resistance?
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biofilm barriers
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Mechanism for development of resistance to erythromycin an dtetracycline?
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active efflux pumps
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mechanism of developing vancomycin resistance?
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altering peptidoglycan subunit
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Toughness def?
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amount of energy a material can absorb before failing, which is the area under the stress/strain curve
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Strength def?
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magnitude of the load at the point where the plate breaks
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Brittleness def?
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opposite of toughness, item breaks at lower value of displacement
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Fatigue strength def?
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breaking after many load cycles
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***antiBx of choice for gonococcal septic arthritis of knee?
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ceftriaxone (3rd gen ceph) because level of PCN and Tetracycline resistance is so high it is completely ineffective in most parts of the world
Fluorquinolones possible alternatives if match sensitivites. |
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CA ass'd with chronic osteomyelitis?
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squamous cell carcinoma
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name of lesions with chronic osteomyelitis?
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Marjolin's ulcers.
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cell surface receptor BMP works by?
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Serine-threonine kinase.
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Mech for warfarin?
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blocks vit K
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Mech heparin?
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affecs antithrombin III and factor Xa
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Gene defect for hyphosphatemic rickets?
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PHEX
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Oxazolidinon antibiotics (eg linezolid) used to treat MRSA mech?
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target ribosomal activity
Linedzoid binds to a site on teh 23S ribosomal RNA of the 50S subunti, preventing formatin of teh 70S initiation complex and interrupting the translational process |
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Penicillin Mech?
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inhibits cell wall synthesis
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Fluoroquinolones mech?
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inhibits DNA gyrase and DNA replication
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Rifampin mech?
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inhibits DNA-dependant RNA polymerase
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Daptomycin mech?
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bacterial cell membrane depolarization interruptine DNA, RNA, and protein synthesis
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Cephalosporins mech?
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inhibits cell wall synthesis
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Quinolones mech?
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inhibits DNA metabolism
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Ampnothericin and Nystatin mech?
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binds sterols in the cell membrane, increasing permeability
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Aminioglycosides mech?
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binds ribosomal subunits and inhibits RNA synthesis
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if see olecranon fx's in peds think ___?
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Osteogenesis imperfecta
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FRAX?
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(Fracture Risk Assessment Tool)
BMI current smoking activity parental history of hip fracture prior history of fx <50yo |
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Botulinum toxin type A mech?
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prevention of presynaptic relese of acetylcholine
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Curare mech?
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nondepolarizing toxin which binds to nicotinic receptor
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Succinylcholine mech?
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depolarizing toxin which binds to nicotinic receptor
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Myasthenia Gravis mech?
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autoimmune disorder which destroys the acetylcholine receptor
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Muscular dystrohpy mech?
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alters muscle sarcolemma stability
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osteoclasts?
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derived from monocytes and macrophages fuse and form multinucleated cells in response to receptor activator of nuclear factro kappa b (RANKL) and macrophage colony stimulating factor (MCSF)
attach to bone surfaces through receptor intecrin (avB3 or vitronectin receptor) Ruffled border refers to invaginations of plasma membrane against bone matrix surface lysosomes move to the ruffled border of osteoclasts and discharge lysosomal enzymes into the resorption region. |
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elastic modulus: what does higher number mean?
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less elastic, is stiffer
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***Osteoporosis is T-scoe of _____?
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<-2.5
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risk factors osteoporosis?
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increased age
postmenopausal women long-term calcium deficiency excessive steroid use alcohol abuse |
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degrees of freedom of hip in what planes?
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3 degrees of freedom:
flexion/extension (sagittal) abd/add (frontal) axial rotation (rotational) |
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what produces RANKL and MCSF?
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osteoblasts and T cells
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"D-zone test"?
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test for inducible clindamycin resistance.
if positive should change to oral doxycycline |
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arthritis findings?
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proteoglycan loss in cartilage matrix
lower compressive modulus higher permeability higher water content decreased tensile modulus decreased shear modulus |
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collagen composition of bone?
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20-25%
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inorganic component of bone?
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60-70%
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Water content of bone?
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5-8%
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Why is MCL considered anisotropic?
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mechanical properties depend on DIRECTION of loading
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nitrogen-containing biphosphonates mech?
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mevalonate patheway by inhibiting GTPase formation, leading to loss of GP prenylation and eventual induction of oseoclast apoptosis
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nonnitrogen-containing biphosphonateds action??
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metabolizing into cytotoxic ATP analogs
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What do conduction velocity changes in peripheral nerve chronic compression syndromes result from?
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Schwann cell proliferation and apoptosis
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Type I Charcot-Marie-Tooth is disorder of ____?
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myelin sheath
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aggrecan?
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cartilage component, is longer core protein with multiple keratin sulfate and condroitin sulfate chains. MW is around 1,000,000. aggregates on hyaluronic acid with link proteins. Can associate with 50 time its weight in water. Resulting swelling pressure is retained by 20% by type II collagen
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Byglycan?
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cartilage component. is a small proteoglycan in cartilage and plays a role in molecular association between cartilage and other molecules
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Versican?
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cartilage component, small proteoglycan in cartilage more associated with the cell surface and plays multiple roles
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Type IX collagen?
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cartilage component plays a role in matrix molecule association with type II collagen
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OsteoCONDUCTIVE graft properties?
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permit ingrowth capillaries and perivascular tissue
scaffold that allows new bone growth sprouts vascular, perivasc, and osteoprogenitor cells on 3D graft structue permits creeping substitution, which allows graft incomporation |
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OsteoINDUCTIVE graft properties?
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stimulates recruitemtn of progenitor cells tahtcan differentiate into osteoblastic cells
specific DMPs are osteoinductive |
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OsteoGENIC bone graft?
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contains viable cells with ability to form bone
***seen ONLY in fresh autograft. Ohter grafts rely on the recruitment of host progenitor cells to differentiate |
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***total VOLUME occupied by chondrocytes in normal cartilage?
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2%
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What factor binds and activates the lipoprotein receptor-related protein 5/6(LRP5/6) during bone develpment?
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WNT protein
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Acetabular cross-over sign?
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cause of anterior femoral neck impingment. Image caused by crossin over of the anterior rim margin on the posterior rim margin due to the retroversion. If fem head and neck configuration normal on hip xray, coxa valga is unlikely
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***Max amount of antibiotic that can be mixed with cement (PMMA) without affecting mechanical properties of cement?
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2g, or 5% of the total weight of PMMA (normal amt of PMMA is 40g so 2g is 5%)
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%gait cycle stance and swing?
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Stance 60%
Swing 40% |
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target of osteoporosis treatment with recombiinant parathyroid hormone (rhPTH)?
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osteoblasts
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What is principle NEGATIVE effect of increasing high crosslinking using gamma radiation sterilization above 2.5-4.0 Mrads?
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poly loses fatigue strength
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cartilage zone with gihgest concentration of proteoglycans?
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deep zone
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Tidemark is boundary between which layers of articular cartilage?
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boundary between calcified and uncalcified layers of articular cartilage
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what is most likely cause of osteolysis in a cemented TKA beneath tibial baseplate when no evidence of wear to the superior surface of the poly?
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polyethlylene fretting wear debris from the backside of the insert. this mocormotion can generate significant amounts of wear degrix sufficient to cause substantial osteolysis
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Ewing's sarcoma characteristics?
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small rount blue-cell tumor w no sig stroma
xray - diaphyseal lesion w onion skinning periosteal rxn or cortical thinning MRI - large soft-tissue component 5-25yo reciprocal translocation chroms 11 and 22 in 90%, resulting in fusion product called ESW/FLI1 |
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P53 mutation ass'd w __?
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Li Fraumeni syndrome and develpment of various cancers
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t(X;18) translocation ass'd w ___?
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synovial sarcoma
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retinoblastoma gene mutation ass'd w ___?
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osteosarcoma
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HER-2 gene amplification ass'd w ___?
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breast cancer most commonly and in osteosarcoma
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metabolism of nucleus pulposus cells?
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anaerobic glycolysis, die to limited vascular supply. May affect DDD
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IsoMETRIC muscle contractions?
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joint angle and muscle length do not change during contraction
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IsoTONIC muscle contractions?
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tension remains unchanged as the muscle's length changes. lifing an object at a constant speed is an example of isotonic contraction
two types: 1)concentric 2)eccentric |
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IsoKINETIC muscle contractions?
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muscle contracts and shortens at a constant rate of speed. This type of muscle contraction requires special, expensive training equipment taht increases the load as it senses the muscle contraction is speeding up. One of fastest ways to incrase muscle strength.
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CONcentric muscle contractions?
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Isotonic contraction in which the muscle tension rises to meet the resistance, then remains the same and the muscle shortens
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ECcentric muscle contraction?
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Isotonic contraction in which the muscle lengthens due to the resistance being greater than the force the muscle is producing.
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type collagen increased in early arthritis?
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type X, in the region of the interface with subchondral bone in most OA pt.s
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Langerhans Cell Histiocytosis (LCH)?
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vertebra plana
Birbeck granules confirmed with CD1 ummunohistochemical staining |
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Birbeck granules?
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tennis-racket shaped cytoplasmic organelles seen on electronic microscope diagnostic of Langerhans Cell Histiocytosis.
Function unknown Dx confirmed with CD1 immunohistochemical staining |
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plasma cells?
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mature B cells that secrete antibodies and are found in multiple myeloma
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Kuppfer cells?
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specialized macrophages located in the liver
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RIckets causes?
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vit D deficiency
renal osteodystrophy X-linked hypophosphatemia vit D malabsorption |
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Rickets characteristics?
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Brittle bones
physeal widening long-bone bowing Looser's lines enlargement of costal cartilages (rachitic rosary?) dorsal kyphosis |
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inflammatory modulators ass'd w HNP?
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TNF-alpha, main offender potentially responsible for nerve root pain in HNP
IL-1 IL-8 |
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most common cause for OA of hip (excluding DDH)
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FAI, cam and pincer
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Why place bone plate on tension side of long bone fx?
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minimizes the bending stiffness
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area most commonly seen w ossification of PLL?
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C4-6
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Mesenchymal cells may differentiate into ___?
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Osteoblasts
Adipocytes Myoblasts Chondroblasts Fibroblasts |
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assay used to examine mRNA level on a particular gene?
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reverse transcription polymerase chain reactin (RT-PCR)
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Western Blot?
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detect protein expression level inside the cells
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ELISA test?
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biochemical technique to detect the presence of antibody or an antigen in a sample
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Immunocytochemical analysis?
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technique to stain cells using antibodies to localize a certain protein within the cells
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Southern blot test?
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technique to detect the genomic DNA expression of a certain gene
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Side effect of Doxorubin?
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Cardiotoxicity
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***Which of the growth plate regions is commonly affected by Salter II injury?
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Hypertrophic zone.
type II is along hypertrophic zone with an attached metaphyseal bony fragment |