Which of the following statements is/are correct in relation to osteoarthritis (OA)?W. Development of OA is strongly associated with articular cartilage degradation.X.  Osteophytes develop at joint margins due to stimulation of periosteal bone/cartilage formation.Y.  OA typically develops asymmetrically, and is present in most individuals over the age of 65.Z.  In OA, articular cartilage matrix loses proteoglycans and gains water; making the cartilage more susceptible to damage.Question 12Select one:a.if only W, X and Y are correctb.if only W and Y are correctc.if only X and Z are correctd.if only Z is correcte.if all are correct

Which of the following statements is/are correct in relation to osteoarthritis (OA)?Question 57Select one:a.Repetitive impulse loading of joints has no bearing on the pathogenesis of OA.b.OA is a degenerative joint disease, which results in a loss of articular cartilage.c.Chondrocytes in articular cartilage produce osteophytes.d.In OA, a pannus develops at joint margins and destroys the articular cartilage.e.OA development is associated with Type III and Type IV hypersensitivity reactions.

Which of the following statements is/are correct in relation to either Osteoarthritis (OA) or Rheumatoid Arthritis (RA)?W. An auto-immune reaction occurs in joints of individuals with RA, but not in joints of people with OA.X.  On the whole, joints are more inflamed in OA than in RA.Y.  Ankylosis (joint fusion) commonly occurs in RA, but is unlikely to occur in OA.Z.  Having osteoporosis increases the risk of developing RA, but not OA.Question 54Select one:a.if only W, X and Y are correctb.if only W and Y are correctc.if only X and Z are correctd.if only Z is correcte.if all are correct

Osteoarthritis (OA) is a disorder marked by the deterioration of articular (hyaline) cartilage, the connective tissue lining the ends of bones at most movable joints.  The progressive erosion of articular cartilage in OA is thought to be caused by an inflammatory response induced by years of biomechanical stress due to excessive compression and friction.  This response involves the release of proteolytic enzymes that break down cartilaginous proteins.  The progressive breakdown of articular cartilage ultimately results in complete exposure of the cortical portion of the underlying subchondral bone with narrowing of the joint space.  Repeated and abnormal joint stress can also cause the development of osteophytes (or small, bony growths) that form on the subchondral bone.  These degenerative processes cause pain and restrict joint movement.Stem cell therapy, in which injected or grafted stem cells are induced to differentiate into chondrocytes (cartilage cells), is a potential new treatment for OA.  To further understand chondrogenesis, researchers have been studying the molecules that regulate the expression and activity of the transcription factor Sox9, which has been shown to promote chondrocyte differentiation.  For example, researchers have found that binding of the growth factor TGF-β to its receptor results in Sox9 activation.MicroRNAs (miRNAs), which are known to alter gene expression by acting at the translational level, are also potential regulators of Sox9.  In particular, miRNA-145 is thought to regulate Sox9 expression by binding to the 3′-untranslated region (UTR) of the Sox9 mRNA transcript.  After chondrocyte differentiation was induced using TGF-β, researchers used western blotting to generate an expression profile of Sox9 and β-actin (a protein not regulated by miRNA-145) in mouse stem cells transfected with miRNA-145, anti-miRNA-145, or neither (Figure 1).Figure 1  Expression of Sox9 in the presence and absence of miRNA-145 or anti-miRNA-145 following induction of chondrocyte differentiationAdapted from Yang B, Guo H, Zhang Y, Chen L, Ying D, Dong S. MicroRNA-145 regulates chondrogenic differentiation of mesenchymal stem cells by targeting Sox9. PLoS ONE. 2011;6(7):e21679. Question 55OA commonly affects large, weight-bearing joints of the lower extremities such as the knee and hip.  Based on the passage, which of the following would most likely occur in a patient with OA involving the knees?A.Deterioration of the yellow bone marrow in affected bonesB.Deposition of excess bone on the epiphyses of affected long bonesC.Loss of hematopoietic function in the red marrow of affected bonesD.Degeneration of compact bone at the diaphysis of affected long bones

Which of the following may cause damage to growing cartilage? (Select all that apply)Question 4Answera.Fluoroquinolonesb.Cephalosporinsc.Aminoglycosidesd.Ciprofloxacin

Which of the following diseases is/are correctly matched to its pathogenesis?W. Osteoarthritis - chronic inflammation and hypersensitivity reactionsX. Rickets - bones are poorly mineralized and soft.Y.  Rheumatoid Arthritis - asymmetrical development in joints of hands and feet.Z. Osteomalacia - bones are poorly mineralized and soft.Question 27Select one:a.if only W, X and Y are correctb.if only W and Y are correctc.if only X and Z are correctd.if only Z is correcte.if all are correct