Basic Science Flashcards
1
Q
What is the most common culture isolate in necrotizing fasciitis?
A
Polymicrobial
2
Q
What is the MOA of calcitonin?
A
Binds to osteoclast receptors, which decreases the ruffled border, followed by cell retraction, and therefore arrest of bone resorption
3
Q
What is denosumab?
A
IgG2 monoclonal antibody against RANKL
4
Q
What is teriparatide?
A
recombinant PTH; anabolic effect via activating osteoblasts
5
Q
What effects does calcitonin have on osteocytes?
A
inhibits apoptosis and increased expression of sclerostin (a Wnt-signaling inhibitor)
6
Q
What is the MOA of enoxaparin?
A
Enoxaparin binds to and increases the activity of antithrombin III
7
Q
What is the MOA of osteoprotegrin?
A
Binds to and sequesters RANKL preventing osteoclastic differentiation
8
Q
What artery provides the blood supply to the outer third the long bone diaphysis?
A
periosteal arteriole
9
Q
What artery provides the blood supply to the inner two thirds of long bones?
A
Nutrient artery
10
Q
Is DBM osteoconductive or osteoinductive?
A
It is both; but not osteogenic
11
Q
Is BMP osteodconductive, osteoinductive, or osteogenic?
A
osteoinductive
12
Q
What is the mechanism of BMP in bone formation?
A
activates mesenchymal cells to transform into osteoblasts and produce bone
13
Q
What is the mechanism of osteoprotegrin in bone formation?
A
OPG inhibits both osteoclast activation and differentiation by acting as a decoy receptor for RANK-L.
14
Q
Bridge plating relies on what kind of bone healing?
A
Relative stability; Secondary (endochondral) bone healing through chondrocytes proliferation and hypertrophy
15
Q
Anatomic fracture reduction relies on what time of bone healing?
A
Absolute stability; primary (intramembranous) bone healing through Haversian canals and cutting cones
16
Q
What is DBM made up of?
A
collagen, TGF-beta, BMP, and residual calcium; it is bone osteoinductive and osteoconductive but not osteogenic
17
Q
What are the FDA indications for use of recombinant human (rh) BMP-2?
A
Acute open tibia shaft fractures treated within 14 days and single level ALIFs
18
Q
What is the definition of strain?
A
Change in length / original length of an object due to an external force
19
Q
Salter-Harris type I fractures typically occur through which zone of the physis?
A
Zone of provisional calcification
20
Q
What region of the physis does collagen type X play a prominent role?
A
Type X collagen is important for bone mineralization and is produced by hypertrophic chondrocytes in the zone of hypertrophy.
21
Q
What is the mechanism of Sclerostin?
A
Sclerostin impedes osteoblast proliferation and function by inhibiting the Wnt signaling pathways and thus inhibits bone formation.
22
Q
What is the MOA of anakinra?
A
Receptor antagonist of IL-1
23
Q
What agar does Neisseria grow on?
A
Thayer Martin
24
Q
What agar does mycobacterium grow on?
A
Lowenstein Jensen
25
What agar does Kingella kingae grow on?
aerobic blood agar (can take a week)
26
Osteoclasts originate from hematopoietic cells from the […] cell lineage?
Macrophage
27
Mirror hand deformity is caused by abnormal duplication of the […]
Zone of polarizing activity
28
[…] are molecules essential for osteoclasts attachment to the bone surface.
Integrins
29
[...] bone formation occurs in longitudinal physeal growth
Endochondral
30
Embryonic long bone formation occurs due to [...] bone formation
endochondral
31
Type [...] collagen associated with endochondral ossification
X
32
Sox-9 gene regulates collagen types [...] [...] [...]
II, IV, and XI
33
[...] delays differentiation of chondrocytes in the zone of hypertrophy
PTHrP
34
The [...] artery is the major source of nutrition to physis
perichondral
35
What physeal zone is affected by Gaucher's disease?
Reserve
36
The reserve physeal zone has [...] oxygen tension
low
37
Which physeal zone has the highest rate of extracellular matrix production?
Proliferative zone
38
Which physeal zone has longitudinal growth and stacking of chondrocytes?
Proliferative zone
39
Which physeal zone has chondrocyte maturation and chondrocyte calcification?
Hypertrophic zone (also has chondrocyte hypertrophy in this zone)
40
Which phase of hypertrophic zone has 5x the chondrocyte growth?
Degenerative phase
41
In the hypertrophic physeal zone, the [...] phase/zone has chondrocyte death which allows calcium release, allowing calcification of matrix
provisional calcification
42
Type [...] collagen produced by hypertrophic chondrocytes important for mineralization
X
43
Which physeal zone is affected by Rickets?
provisional zone of calcification in hypertrophic zone
44
Fractures most commonly occur through zone of [...]
provisional calcification in the hypertrophic zone
45
Which physeal zone is affected by enchondromas?
Hypertrophic zone
46
Which physeal zone is affected by mucopolysaccharidoses?
hypertrophic zone
47
Metaphyseal "corner fracture" in child abuse affects the [...] physeal zone
primary spongiosa
48
What physeal zone is affected by renal SCFE?
Secondary spongiosa
49
Which physeal zone is affected by achondroplasia?
proliferative zone
50
Which physeal zone is affected by giantism?
proliferative zone
51
The groove of Ranvier is affected by what bony tumor?
Osteochondroma
52
What physeal ring increases the mechanical strength of the physis and is responsible for appositional bone growths?
Groove of Ranvier
53
In embryonic long bone formation, [...] cells differentiate into chondroblasts that form the hyaline cartilaginous skeletal precursor of the bones
mesenchymal
54
Which cells produce RANKL?
Osteoblasts
55
Which cells have RANK
Osteoclasts and osteoclast precursors
56
[...] is a decoy receptor produced by osteoblasts and stromal cells that binds to and sequesters RANKL
Osteoprotegerin
57
Osteoprotegerin [...] osteoclast differentiation, fusion, and activation.
inhibits
58
Which cell produced osteoprotegerin?
Osteoblasts
59
Osteoclast Inhibition [...] bone resorption
decreases
60
Transforming growth factor beta (TGF beta) increases [...], thereby decreasing bone resorption
osteoprotegerin
61
Interleukin-[...] suppresses osteoclasts
10
62
RANKL (ligand) is secreted by [...] and binds to the RANK receptor on [...] and [...] cells.
osteoblasts; osteoclast precursor; mature osteoclast
63
PTH [...] adenylyl cyclase, while estrogen [...] adenylyl cyclase.
stimulates; inhibits
64
PTH binds to cell-surface receptors on [...] to stimulate production of RANKL and M-CSF
osteoblasts
65
IL-[...] stimulates osteoclast differentiation and thus bone resorption
1
66
when the strain is below [...] percent, primary bone healing will occur
2
67
When the strain is between [...] percent, secondary bone healing will occur.
2-10
68
Primary bone healing occurs with [...] healing.
intramembranous
69
Haversian remodeling is seen in [...] bone healing
primary/intramembranous
70
Intramembranous healing is [...] bone healing
primary
71
Enchondral bone healing is [...] bone healing
secondary
72
Secondary bone healing occurs with [...] bone healing.
endochondral
73
During fracture healing [...] tissue tolerates the greatest strain before failure
granulation
74
Inhibition of COX-2 (ie NSAIDs) causes repression of [...], which are critical for differentiation of osteoblastic cells
runx-2/osterix
75
Type [...] collagen is produced early in fracture healing and then followed by type [...] collagen expression
Type II collagen (cartilage); Type I collagen (bone)
76
Chondrocytes undergo terminal differentiation during which stage of fracture healing?
remodeling
77
In fracture healing, Type [...] collagen is expressed by hypertrophic chondrocytes as the extraarticular matrix undergoes calcification
X
78
In fracture healing, Type X collagen is expressed by [...] as the extraarticular matrix undergoes calcification
hypertrophic chondrocytes
79
Low intensity pulsed ultrasound [...] fracture healing and [...] mechanical strength of callus (including torque and stiffness).
accelerates; increases
80
Direct current bone stimulators decrease osteoclast activity and increase osteoblast activity by [...] oxygen concentration and [...] local tissue pH
reducing; increasing
81
COX-2 promotes fracture healing by causing mesenchymal stem cells to differentiate into [...]
osteoblasts
82
What is the definition of strain?
change in length/original length (L)
83
By what mechanism does calcitonin inhibit bone resorption?
Calcitonin inhibits osteoclastic bone resorption directly by binding to the osteoclast
84
A deactivating mutation in the parathyroid hormone-related peptide (PTHrP) receptor would lead to [...] maturation in the zone of hypertrophy
accelerated
85
During the early callus phase of bone healing, MMP-13 is expressed by [...] to degrade the cartilaginous extracellular matrix.
terminally differentiated chondrocytes
86
BMP 2,4,6, and 7 all exhibit osteo-[...] activity.
inductive
87
rhBMP-2 is approved for FDA use in what spine procedure?
Single level ALIF from L2 to S1 for degenerative disc disease
88
rhBMP-2 is approved by FDA use in what trauma procedure?
open tibia shaft treated with IMN within 14 days
89
TGF-beta stimulates production of Type [...] collagen
II
90
What bone graft substitute resorbs the fastest?
calcium sulfate
91
What bone graft substitute resorbs the slowest?
hydroxyapatite
92
5 years after implantation, allograft articular cartilage is completely [...]
acellular
93
An [...] bone graft material acts as a structural framework for bone growth
osteoconductive
94
BMP is an example of an osteo-[...] material.
inductive
95
Which synthetic bone grafting material has the highest compressive strength?
Calcium phosphate
96
An osteo-[...] material is a material that contains factors to stimulate bone growth.
inductive
97
Calcium sulfate is osteo-[...] only
conductive
98
DBM is both osteo-[...] and osteo-[...]
Osteoinductive and osteoconductive
99
In iliac crest bone graft harvesting, there is a higher complication rate with [...] versus [...] harvesting
anterior; posterior
100
Calcium [...] bone graft substitute associated with increased serous wound drainage
sulfate
101
What is the MOA of botox?
Blocks acetylcholine release at end plate
102
[...] are the most abundant cells early on after acute muscle injury
Neutrophils
103
Bone morphogenetic proteins (BMPs) uses [...] receptors to stimulate proliferation and differentiation of pluripotent mesenchymal stem cells into bone-forming cells.
serine-threonine kinase
104
Type [...] collagen makes up 85% of dry weight of tendons
I
105
[...] is the most predominant proteoglycan in tendon
decorin
106
What two types of collagen make up tendons?
Type I (85%); Type III (0-5%)
107
[...] are predominant cell type seen in tendons.
fibroblasts
108
Tendon repairs are weakest at [...] days
7-10
109
Hyaline cartilage is composed of type [...] collagen
II
110
Articular cartilage water content [...] with osteoarthritis
increases
111
In hyaline (articular) cartilage, [...] function to provide compressive strength and attract water
proteoglycans
112
Which proteoglycan found in articular (hyaline) cartilage is most responsible for hydrophilic behavior?
Aggrecan
113
Normal articular cartilage is composed of [...] zones and the tidemark
three
114
Which zone of articular cartilage have cartilage progenitor cells been found in?
Superficial
115
Which zone of articular cartilage are the collagen fibers parallel to the joint?
Superficial
116
The [...] zone of articular cartilage has the highest concentration of collagen and lowest concentration of proteoglycans
superficial
117
Which zone of articular cartilage is the thickest?
Intermediate
118
Which growth factor is responsible for osteophyte formation?
TGF-beta
119
With age, articular chondrocytes [...] in size
increase
120
With age, there is an [...] in protein content of articular cartilage
increase
121
With age, there is a [...] in absolute number of cells (chondrocytes) in articular cartilage.
decrease
122
With age, there is a [...] in water content of the articular cartilage.
decrease; (note: differentiates from osteoarthritis where water content actually increases)
123
Predominant pathway of chondrocyte death in articular cartilage injury is believed to be via [...].
apoptosis; (note: NOT necrosis)
124
Deep articular cartilage injury (eg lacerations) lead to healing via formation of [...] versus hyaline cartilage
Fibrocartilage (note: this response forms type I collagen)
125
The superficial zone of articular cartilage has the [...] content of collagen and the [...] content of proteoglycans relative to the other zones
highest; lowest
126
What is the inheritance pattern of Marfan's syndrome?
AD
127
What is the inheritance pattern of Malignant Hyperthermia?
AD
128
What is the inheritance pattern of Ehlers-Danlos?
AD
129
What is the inheritance pattern of Osteogenesis imperfecta (types I-IV)?
AD
130
What is the inheritance pattern of hemophilia?
X-linked recessive
131
What is the inheritance pattern of Charcot-Marie-Tooth?
AD
132
With [...] deformation, the material returns to original shape when load is removed
elastic
133
Is elastic deformation reversible or irreversible?
reversible
134
Is plastic deformation reversible or irreversible?
Irreversible
135
In [...] deformation, material DOES NOT return to original shape when load is removed.
Plastic
136
The definition of [...] is amount of energy per volume a material can absorb before failure.
toughness
137
[...] is calculated as the area under the stress/strain curve
Toughness
138
The [...] is the the transition point between elastic and plastic deformation
yield point
139
The [...] is defined as the load to failure.
Ultimate (Tensile) Strength
140
A brittle material undergoes [...] deformation only, and little to no [...] deformation
elastic; plastic
141
The bending rigidity of a plate is proportional to [...]
thickness to the 3rd power
142
An IMN is a load-[...] device.
sharing
143
A plate construct is a load-[...] device.
bearing
144
Bending rigidity is proportional to the radius to the [...] power for a solid nail
4th
145
Bending rigidity is proportional to the radius to the [...] power for a hollow nail
3rd
146
Increasing femoral offset [...] strain on medial cement mantle
increases
147
Increasing femoral offset increases strain on [...] cement mantle.
medial
148
Crutch walking requires [...] energy than walking with a prosthesis
more
149
For upper extremity prostheses, there are better outcomes if prosthetic is fitted within [...] days
30
150
A higher modulus of elasticity indicates a [...] material.
stiffer
151
Young's modulus is a measure of the [...] of a material in the elastic zone that is calculated by measuring the slope of the stress-strain curve in the elastic zone.
stiffness (ie - ability to resist deformation)
152
[...] is defined as: progressive deformation of a material in response to a constant force over an extended period
Creep
153
[...] is defined as: failure below the ultimate tensile strength after numerous loading cycles
Fatigue
154
Which physeal zone is affected by Rickets?
Zone of provisional calcification (hypertrophic zone)
155
What dose of Vit C has been used for prevention of CPRS in distal radius fractures treated conservatively?
500 mg daily x 50 days
156
Which pathway of clot formation is activated during dissection?
Extrinsic pathway
157
Acute DVTs are defined as clots are developing or have recently developed within [...] days
28
158
What is the MOA of fondaparinux?
Indirect Xa inhibitor (works through ATIII)
159
What is the MOA of dabigatran?
Direct thromBIn inhibitor
160
Under normal conditions thromboxane is responsible for the aggregation of [...] that form blood clots
platelets
161
Under normal conditions [...] is responsible for the aggregation of platelets that form blood clots
thromboxane
162
Is ASA an irreversible or reversible inhibitor of COX within platelets?
Irreversible
163
What is the MOA of subQ heparin?
binds and enhances ability of antithrombin III to inhibit factors IIa, III, Xa
164
What factors are inhibited by subQ heparin?
IIa, III, Xa
165
What is the reversal agent for subQ heparin?
protamine sulfate
166
What is the reversal agent for LMWH (enoxaparin)?
protamine sulfate
167
LMWH acts in several sites of the coagulation cascade, with its principal action being inhibition of factor [...]
Xa
168
What is the MOA of warfarin?
inhibits vitamin K 2,3-epoxide reductase
169
What factors are affected by warfarin?
Factors II, VII, IX, X, protein C, protein S
170
What is the reversal agent for dabigatran?
idarucizumab
171
TXA is a synthetic derivative of the amino acid [...]
lysine
172
TXA competitively inhibits the activation of [...] by binding to the lysine binding site
plasminogen
173
Aspirin irreversibly blocks the formation of [...] in platelets, which inhibits platelet aggregation and thus the formation of a clot.
thromboxane A2
174
Heparin works by binding to and enhancing the ability of [...] to inhibit factors IIa, III, Xa
antithrombin III
175
Enoxaparin works by binding to [...] to form a complex that irreversibly inactivates clotting factor [...].
antithrombin; Xa
176
In antiphospholipid syndrome, antibodies are formed against [...]
Protein C and possibly Protein S
177
Total hip arthroplasty with [...] components are a risk factor for fragility fractures
constrained
178
History of 1 hip fracture results in up to [...] - fold increased risk of 2nd hip fracture
10
179
Bisphosphonates results in a [...] ruffled border on histology
flattened
180
181
Bisphosphonates are considered when with T score between -1.0 and -2.5 at the femoral neck/spine and 10-year risk of major osteoporosis-related fracture ≥ [...]% by FRAX calculation
20
182
[...]-containing bisphosphonates inhibit farnesyl pyrophosphate synthase (mevalonate pathway)
Nitrogen
183
[...]-containing bisphosphonates produce toxic ATP analog
Non-nitrogen
184
What is the MOA of calcitonin in osteoporosis?
Binds membrane receptors on osteoclasts to inhibit resorption
185
Teriparatide is contraindicated in [...] due to potential increased risk of osteosarcoma.
Paget's disease
186
What medication used in osteoporosis is a humanized monoclonal Ig2 that activates Wnt pathway by binding sclerostin?
Romosozumab
187
History of [...] vertebral fractures is the strongest indicated for further compression fractures in postmenopausal women
2
188
[...] are the primary cellular mediator of tissue destruction in RA
mononuclear cells
189
In Rheumatoid Arthritis, the [...] joint of hand is usually spared
DIP
190
[...] is the most sensitive and specific test for rheumatoid arthritis.
Anti-CCP
191
Methotrexate is a [...] analogue.
folate
192
What is the MOA of anakinra?
Recombinant IL1 receptor antagonist
193
What is the MOA of Rituximab?
Monoclonal antibody to CD20 antigen
194
[...] is a selective co-stimulation modulator that binds to CD80 and CD86 (inhibits T cells)
Abatacept
195
[...] is a monoclonal antibody targeting IL-12 and IL-23
Ustekinumab (Stelera)
196
What is the preoperative management for methotrexate?
Continue
197
What is the preoperative management for Rituximab?
Stop 7 months before major surgery
198
In a Boutonniere deformity, the lateral bands subluxate [...] to axis of rotation of PIP
volar
199
In a Swan neck deformity, the lateral bands subluxate [...] to PIP axis of rotation
dorsal
200
What is Mannerfelt syndrome?
Seen in RA; rupture of FPL (most common flexor rupture) in carpal tunnel due to scaphoid spur
201
In RA, which extensor tendon is most commonly ruptured?
EDM
202
In a TEA for RA, a [...] device has best results
semiconstrained
203
In RA of the shoulder, [...] glenoid wear is most commonly seen.
central
204
In RA, [...] is the most significant risk factor for development of SSI.
history of prior surgical site infection
205
Etanercept should be discontinued [...] prior to major surgical procedures
2 weeks
206
Rituximab should be held for [...]prior to major surgical procedures
7 months
207
The National Osteoporosis Foundation recommends a daily intake of [...] mg of calcium and [...] IUs of vitamin D for adults over the age of 50.
1,200-1500; 800-1,000
208
Low serum phosphate and normal calcium levels are found in what common etiology of hereditary rickets?
X-linked hypophosphatemic rickets
209
Tocilizumab is an [...] receptor inhibitor
IL-6
210
Which cells produce calcitonin?
parafollicular cells
211
Which cells produce parathyroid hormone?
Chief cells
212
Osteoporosis is characterized by [...] bone quantity and [...] bone quality.
decreased; normal
213
COX enzymes catalyze the formation of prostaglandins and thromboxane from [...]
arachidonic acid
214
Indomethicin inhibibits [...] inflammatory mediators
leukotriene
215
COX inhibitors inhibit callus formation by inhibiting [...] ossification
endochondral
216
In use of COX inhibitors, [...] bone healing is more likely to be effected than [...] bone healing
secondary; primary
217
Linezolid binds to the [...] portion of the ribosomal subunit and inhibits protein synthesis.
23s
218
When culture results reveal erythromycin-resistant MRSA, a [...] test should be performed to check for inducible clindamycin resistance.
D-zone
219
What is the primary mechanism of action of tobramycin?
irreversibly binding to 30S ribosomal subunit
220
Bisphosphonates have been shown to [...] fracture incidence and bone pain while [...] bone density and overall function in OI patients.
decrease; improving
221
[...] - containing bisphosphonates target farnesyl diphosphate synthase, a component of the mevalonate (cholesterol) pathway.
Nitrogen
222
[...]-containing bisphosphonates result in cytotoxic ATP to accumulate with an end result of apoptosis.
Non-nitrogen
223
What is the MOA of acetaminophen?
inhibits prostaglandin E2 production through its effect on interleukin-1 beta
224
What is the MOA of gabapentin?
binding the alpha2delta subunit of voltage-dependent calcium channels on the presynaptic membrane inhibiting neurotransmitter release
