1.Rate of newly synthesized osteoid mineralization can be best estimated by -
a.Tetracycline labeling
b.Alizarin red stain
c.Calcein stain
d.Van kossa stain
Tetracycline labeling for osteoid mineralization
Tetracycline labeling is the method of choice for estimating newly synthesized osteoid mineralization in human.
Tetracycline is incorporated into new areas of osteoid that are being laid down but not yet mineralized (osteoid seams)
To estimate the rate of newly synthesized osteoid mineralization tetracycline is administered to the subject at two defined time points.
If the time interval between the two course is known , both the rate and extent of mineralization can be measured.
Tetracycline labeling allows a distinction to be made between defective mineralization (osteomalacia) and increased osteoid synthesis (bone remodeling states) by revealing the calcification front.
Other stain used for osteoid mineralization
Other stain can also be used for this purpose, but they are inferior to tetracycline:
Alizarin red
Calcein
Von-Kossa
2.The one most consistent sign of fresh fracture is
a.Crepitus
b.Bony tenderness
c.Deformity
d.Abnormal mobility
e.Shortening of bone
Many guides have given crepitus as the answer of this question. They are wrong as crepitus can be elicited in the displaced fractures only. It cannot be elicited in undisplaced or impacted fractures. How can it be the most consistent feature?
Following statements will clear alI the confusion :-
“Tenderness over the fracture site is the single most consistent sign present in every fracture. In an incomplete or impacted or undisplaced fracture, local tenderness will be the only sign”. — Essentials of orthopedics surgery “Crepitus, abnormal mobility, deformity and loss of transmitted movement cannot be elicited in undisplaced fractures, stress fractures, impacted fractures, etc”. — Ebnezar
Most consistent symptom of fracture →Pain
Most consistent sign of fracture → Tenderness