Z- Abos Basic Science

Front 1

Glucosamine method of action?

Back 1

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

Front 2

relationship of bending stiffness to diameter? (eg pin)

Back 2

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

Front 3

how do metastatic tumors attach to the endothelial cell layers of the host bone?

Back 3

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.

Front 4

What is E-cadherin?

Back 4

CAM (Cell Adhesion Molecule) in tumor cells allowing them to release from primary tumor focus into the bloodstream

Front 5

Matrix Metalloproteinases? (MMP)

Back 5

used by tumor cells to invade the basement membrane and extracellular matrices

Front 6

Vascular Endothelial Growth Factor? (VEGF)?

Back 6

expressed by timor cells to induce amngiogenesis into the degraded venous basement membrane and extracellular matrix

Front 7

CHemokine ligand 12 (CSCL12)?

Back 7

found in stromal cells of normal bone marrow and acts as a homing chemokine to certain tumor cells and promotes the targeting of bone.

Front 8

What is the mechanical property descriptive term for the mechanical properties of bone?

Back 8

Anisotropic, or that the mechanical properties of bone vary with the orioentation of the specimen within bone because of the orientation of collagen fibers.

Front 9

percent insufficiency fractures of large cortical structureal allografts?

Back 9

15-30%

Front 10

Rickets:

Back 10

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)

Front 11

hyperparathyroidism - cause and consequences?

Back 11

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

Front 12

Jansen syndrome?

Back 12

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

Front 13

Renal osteodystrophy?

Back 13

sclerotic vertebra

"rugger jersey"

Front 14

**Most important adaptation from endurance training?

Back 14

increased capillary density!

Front 15

Strength training muscle adaptations?

Back 15

increased recruitment of motor units
Hyperplasia (formation of additional myofibers)
Hypertorphy of indifidual myofibrils

Front 16

***C6-7 HNP most likely distribution of symptoms?

Back 16

C7 radiculopathy
pain at forearm and hand
numbnes of middle finger
weakness triceps
weakness finger extensors

Front 17

***C3-4 HNP symptoms?

Back 17

C4 radiculopathy
pain post neck and scapula
numbness over the clavicle
weakness of the head and neck extensors

Front 18

***C4-5 HNP symptoms?

Back 18

C5 radiculopathy
pain in the shoulder
numbness over the lateral shoulder
weakness of the deltoid

Front 19

***C5-6 HNP symptoms?

Back 19

C6 radiculopathy
pain at elbow
numbness over the thumb and index finger
weakness of biceps
weakness of wrist extensors

Front 20

***C7-T1 HNP symptoms?

Back 20

T1 radiculopathy
pain at the wrist
numbness in little and ring fingers
Weak finger flexors

Front 21

Lubricin: what is it and what type of lubrication?

Back 21

Boundary lubrication. Is mucinous gllycoprotein that is critical to lubrication in joints. Also affect tendon sheaths and pericardium

Front 22

Hydrodynamic lubrication?

Back 22

when fluid separates two surfaces when one is sliding on another

Front 23

Squeeze film lubrication?

Back 23

When the layer of fluid is slowly being wqueezed from between two surfaces

Front 24

Elastohydrodynamic lubrication?

Back 24

Deformation of a surgace moving on another and a thin film separates the surface

Front 25

Serotonin syndrome?

Back 25

acute adverse drug reaction caused by excess of seotonin activity
produces an array of automonic and somatic effects: abd pain, HA's, diarrhea, clonus

Front 26

Rx serotonin syndrome?

Back 26

benzodiazepines to abate symptoms and in severe cases give serotonin antagonists

Front 27

def Fatigue?

Back 27

gradual accumulation and progression of crack in the material which after many cycles of loading can lead to gross failure

Front 28

def Plastic deformatin ?

Back 28

if loaded above yield point the object will have some permanent, or plastic, deformation

Front 29

def Creep?

Back 29

gradual accumulation of permanent (plastic) deformation over time

Front 30

def Torsion?

Back 30

torque being applied about the long axis of a bone or an implant

Front 31

where is 1,25-hydroxycholecalciferon produced and wat does it do?

Back 31

Proximal convoluted tubule of the kidneys, and is the active form of Vit D which is the foremost regulator of intestinal calcium absorption

Front 32

What will result from decrased phosphate?

Back 32

results in hypercalcuria. Appears to be a direct efffect of phosphate to decreased calcum reabsorption in the distal nephron

Front 33

what changes happen in articular cartilage with aging?

Back 33

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

Front 34

C4 wheelchair needs?

Back 34

puffer control

Front 35

C5 wheelchair needs?

Back 35

hand controls

Front 36

C6 wheelchair needs?

Back 36

manual wheelchair and sliding board transfers

Front 37

C7 wheelchair needs?

Back 37

allows independant transfers

(note NO cervical injury routinely allows ambulation wit crutches and leg braces)

Front 38

effect of methylprednisolone administered to spinal injury?

Back 38

decrased extent of cord hemorrhage only. No difference in cord edema, or improved clinical outcomes

Front 39

how do biphosphonates work?

Back 39

antiresorptive agents act by targeting osteoclastice bone resorption

Front 40

How does calcitonin work?

Back 40

inhibits osteoclastic bone resorption

Front 41

How does TNF-a work?:

Back 41

inhibits osteoblastic activity and enhances osteoclastic bone resorption

Front 42

***How does MRSA develop resistance to penicillinase-stable antibiotics?

Back 42

by genetic mutation!
Specifically, genetic mutatin of mecA encoding an altered penicillin binding protein

Front 43

how does resistance to tetracyclines, quinolones, trimethoprim, beta-lactam antibiotics develop?

Back 43

Cell wall permeability changes

Front 44

how does Salmonella develop antibiotic resistance?

Back 44

biofilm barriers

Front 45

Mechanism for development of resistance to erythromycin an dtetracycline?

Back 45

active efflux pumps

Front 46

mechanism of developing vancomycin resistance?

Back 46

altering peptidoglycan subunit

Front 47

Toughness def?

Back 47

amount of energy a material can absorb before failing, which is the area under the stress/strain curve

Front 48

Strength def?

Back 48

magnitude of the load at the point where the plate breaks

Front 49

Brittleness def?

Back 49

opposite of toughness, item breaks at lower value of displacement

Front 50

Fatigue strength def?

Back 50

breaking after many load cycles

Front 51

***antiBx of choice for gonococcal septic arthritis of knee?

Back 51

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.

Front 52

CA ass'd with chronic osteomyelitis?

Back 52

squamous cell carcinoma

Front 53

name of lesions with chronic osteomyelitis?

Back 53

Marjolin's ulcers.

Front 54

cell surface receptor BMP works by?

Back 54

Serine-threonine kinase.

Front 55

Mech for warfarin?

Back 55

blocks vit K

Front 56

Mech heparin?

Back 56

affecs antithrombin III and factor Xa

Front 57

Gene defect for hyphosphatemic rickets?

Back 57

PHEX

Front 58

Oxazolidinon antibiotics (eg linezolid) used to treat MRSA mech?

Back 58

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

Front 59

Penicillin Mech?

Back 59

inhibits cell wall synthesis

Front 60

Fluoroquinolones mech?

Back 60

inhibits DNA gyrase and DNA replication

Front 61

Rifampin mech?

Back 61

inhibits DNA-dependant RNA polymerase

Front 62

Daptomycin mech?

Back 62

bacterial cell membrane depolarization interruptine DNA, RNA, and protein synthesis

Front 63

Cephalosporins mech?

Back 63

inhibits cell wall synthesis

Front 64

Quinolones mech?

Back 64

inhibits DNA metabolism

Front 65

Ampnothericin and Nystatin mech?

Back 65

binds sterols in the cell membrane, increasing permeability

Front 66

Aminioglycosides mech?

Back 66

binds ribosomal subunits and inhibits RNA synthesis

Front 67

if see olecranon fx's in peds think ___?

Back 67

Osteogenesis imperfecta

Front 68

FRAX?

Back 68

(Fracture Risk Assessment Tool)
BMI
current smoking activity
parental history of hip fracture
prior history of fx <50yo

Front 69

Botulinum toxin type A mech?

Back 69

prevention of presynaptic relese of acetylcholine

Front 70

Curare mech?

Back 70

nondepolarizing toxin which binds to nicotinic receptor

Front 71

Succinylcholine mech?

Back 71

depolarizing toxin which binds to nicotinic receptor

Front 72

Myasthenia Gravis mech?

Back 72

autoimmune disorder which destroys the acetylcholine receptor

Front 73

Muscular dystrohpy mech?

Back 73

alters muscle sarcolemma stability

Front 74

osteoclasts?

Back 74

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.

Front 75

elastic modulus: what does higher number mean?

Back 75

less elastic, is stiffer

Front 76

***Osteoporosis is T-scoe of _____?

Back 76

<-2.5

Front 77

risk factors osteoporosis?

Back 77

increased age
postmenopausal women
long-term calcium deficiency
excessive steroid use
alcohol abuse

Front 78

degrees of freedom of hip in what planes?

Back 78

3 degrees of freedom:
flexion/extension (sagittal)
abd/add (frontal)
axial rotation (rotational)

Front 79

what produces RANKL and MCSF?

Back 79

osteoblasts and T cells

Front 80

"D-zone test"?

Back 80

test for inducible clindamycin resistance.
if positive should change to oral doxycycline

Front 81

arthritis findings?

Back 81

proteoglycan loss in cartilage matrix
lower compressive modulus
higher permeability
higher water content
decreased tensile modulus
decreased shear modulus

Front 82

collagen composition of bone?

Back 82

20-25%

Front 83

inorganic component of bone?

Back 83

60-70%

Front 84

Water content of bone?

Back 84

5-8%

Front 85

Why is MCL considered anisotropic?

Back 85

mechanical properties depend on DIRECTION of loading

Front 86

nitrogen-containing biphosphonates mech?

Back 86

mevalonate patheway by inhibiting GTPase formation, leading to loss of GP prenylation and eventual induction of oseoclast apoptosis

Front 87

nonnitrogen-containing biphosphonateds action??

Back 87

metabolizing into cytotoxic ATP analogs

Front 88

What do conduction velocity changes in peripheral nerve chronic compression syndromes result from?

Back 88

Schwann cell proliferation and apoptosis

Front 89

Type I Charcot-Marie-Tooth is disorder of ____?

Back 89

myelin sheath

Front 90

aggrecan?

Back 90

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

Front 91

Byglycan?

Back 91

cartilage component. is a small proteoglycan in cartilage and plays a role in molecular association between cartilage and other molecules

Front 92

Versican?

Back 92

cartilage component, small proteoglycan in cartilage more associated with the cell surface and plays multiple roles

Front 93

Type IX collagen?

Back 93

cartilage component plays a role in matrix molecule association with type II collagen

Front 94

OsteoCONDUCTIVE graft properties?

Back 94

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

Front 95

OsteoINDUCTIVE graft properties?

Back 95

stimulates recruitemtn of progenitor cells tahtcan differentiate into osteoblastic cells
specific DMPs are osteoinductive

Front 96

OsteoGENIC bone graft?

Back 96

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

Front 97

***total VOLUME occupied by chondrocytes in normal cartilage?

Back 97

2%

Front 98

What factor binds and activates the lipoprotein receptor-related protein 5/6(LRP5/6) during bone develpment?

Back 98

WNT protein

Front 99

Acetabular cross-over sign?

Back 99

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

Front 100

***Max amount of antibiotic that can be mixed with cement (PMMA) without affecting mechanical properties of cement?

Back 100

2g, or 5% of the total weight of PMMA (normal amt of PMMA is 40g so 2g is 5%)

Front 101

%gait cycle stance and swing?

Back 101

Stance 60%

Swing 40%

Front 102

target of osteoporosis treatment with recombiinant parathyroid hormone (rhPTH)?

Back 102

osteoblasts

Front 103

What is principle NEGATIVE effect of increasing high crosslinking using gamma radiation sterilization above 2.5-4.0 Mrads?

Back 103

poly loses fatigue strength

Front 104

cartilage zone with gihgest concentration of proteoglycans?

Back 104

deep zone

Front 105

Tidemark is boundary between which layers of articular cartilage?

Back 105

boundary between calcified and uncalcified layers of articular cartilage

Front 106

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?

Back 106

polyethlylene fretting wear debris from the backside of the insert. this mocormotion can generate significant amounts of wear degrix sufficient to cause substantial osteolysis

Front 107

Ewing's sarcoma characteristics?

Back 107

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

Front 108

P53 mutation ass'd w __?

Back 108

Li Fraumeni syndrome and develpment of various cancers

Front 109

t(X;18) translocation ass'd w ___?

Back 109

synovial sarcoma

Front 110

retinoblastoma gene mutation ass'd w ___?

Back 110

osteosarcoma

Front 111

HER-2 gene amplification ass'd w ___?

Back 111

breast cancer most commonly and in osteosarcoma

Front 112

metabolism of nucleus pulposus cells?

Back 112

anaerobic glycolysis, die to limited vascular supply. May affect DDD

Front 113

IsoMETRIC muscle contractions?

Back 113

joint angle and muscle length do not change during contraction

Front 114

IsoTONIC muscle contractions?

Back 114

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

Front 115

IsoKINETIC muscle contractions?

Back 115

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.

Front 116

CONcentric muscle contractions?

Back 116

Isotonic contraction in which the muscle tension rises to meet the resistance, then remains the same and the muscle shortens

Front 117

ECcentric muscle contraction?

Back 117

Isotonic contraction in which the muscle lengthens due to the resistance being greater than the force the muscle is producing.

Front 118

type collagen increased in early arthritis?

Back 118

type X, in the region of the interface with subchondral bone in most OA pt.s

Front 119

Langerhans Cell Histiocytosis (LCH)?

Back 119

vertebra plana
Birbeck granules
confirmed with CD1 ummunohistochemical staining

Front 120

Birbeck granules?

Back 120

tennis-racket shaped cytoplasmic organelles seen on electronic microscope diagnostic of Langerhans Cell Histiocytosis.
Function unknown
Dx confirmed with CD1 immunohistochemical staining

Front 121

plasma cells?

Back 121

mature B cells that secrete antibodies and are found in multiple myeloma

Front 122

Kuppfer cells?

Back 122

specialized macrophages located in the liver

Front 123

RIckets causes?

Back 123

vit D deficiency
renal osteodystrophy
X-linked hypophosphatemia
vit D malabsorption

Front 124

Rickets characteristics?

Back 124

Brittle bones
physeal widening
long-bone bowing
Looser's lines
enlargement of costal cartilages (rachitic rosary?)
dorsal kyphosis

Front 125

inflammatory modulators ass'd w HNP?

Back 125

TNF-alpha, main offender potentially responsible for nerve root pain in HNP
IL-1
IL-8

Front 126

most common cause for OA of hip (excluding DDH)

Back 126

FAI, cam and pincer

Front 127

Why place bone plate on tension side of long bone fx?

Back 127

minimizes the bending stiffness

Front 128

area most commonly seen w ossification of PLL?

Back 128

C4-6

Front 129

Mesenchymal cells may differentiate into ___?

Back 129

Osteoblasts
Adipocytes
Myoblasts
Chondroblasts
Fibroblasts

Front 130

assay used to examine mRNA level on a particular gene?

Back 130

reverse transcription polymerase chain reactin (RT-PCR)

Front 131

Western Blot?

Back 131

detect protein expression level inside the cells

Front 132

ELISA test?

Back 132

biochemical technique to detect the presence of antibody or an antigen in a sample

Front 133

Immunocytochemical analysis?

Back 133

technique to stain cells using antibodies to localize a certain protein within the cells

Front 134

Southern blot test?

Back 134

technique to detect the genomic DNA expression of a certain gene

Front 135

Side effect of Doxorubin?

Back 135

Cardiotoxicity

Front 136

***Which of the growth plate regions is commonly affected by Salter II injury?

Back 136

Hypertrophic zone.
type II is along hypertrophic zone with an attached metaphyseal bony fragment