Osteoclasts are not activated in XXXX .

@entity1 @entity102 @entity9215 @entity5298 @entity5479 @entity3540 @entity79 @entity2159
UNASSIGNED: It is unclear whether osteoclasts are present and activated in @entity3540 . We explored the expression of messenger RNA (mRNA) for osteoclast biomarkers and regulating factors in @entity5479 to elucidate the level of osteoclast activity in this disease. Bone powder was collected from 14 @entity1 with cholesteatomatous and @entity102 media during tympanomastoidectomy, separately from cortical bone of the mastoid (clean bone powder), from bone neighboring @entity3540 ( @entity79 ), and from bone of the air cells and antrum of @entity102 media @entity1 (noncholesteatomatous bone powder). The samples collected were soaked in TRIzol reagent, and total RNA was extracted and purified by the acid guanidinium thiocyanate-phenol-chloroform method, followed by the use of magnetic bead technology. The sample was then subjected to quantitative reverse transcription polymerase chain reaction for receptor activator of nuclear factor kB (RANK), tartrate-resistant acid phosphatase (TRAP), cathepsin K (CTSK), osteoclast-associated receptor ( @entity9215 ), calcitonin receptor (CALCR), matrix metalloproteinase  9 (MMP9), receptor activator of nuclear factor kB ligand ( @entity5298 ), and osteoprotegerin ( @entity2159 ). There was no significant difference in the expression of TRAP, CTSK, @entity9215 , CALCR, MMP9, or @entity2159 among the clean, cholesteatomatous, and noncholesteatomatous bone powder. On the other hand, the expression of RANK and @entity5298 was significantly lower in the @entity79 than in the noncholesteatomatous bone powder (P  =  0.003 and P  =  0.028, respectively). The @entity5298 mRNA/ @entity2159 mRNA ratio did not differ among the three samples. These results indicate that osteoclasts are unlikely to be activated in @entity3540 . Bone resorption mechanisms not mediated by osteoclasts may need to be reappraised in @entity3540 research in future studies.
