[Study on the Relationship between Integrin 2A and Drug Resistance in Chronic Myeloid Leukemia].

OBJECTIVE: To explore the expression pattern and clinical significance of Integral membrane protein 2A（ITM2A） in drug resistant patients with chronic myeloid leukemia (CML). METHODS: The expression of ITM2A in CML was evaluated by qRT-PCR, Western blot and immunocytochemistry. In order to understand the possible biological effects of ITM2A, apoptosis, cell cycle and myeloid differentiation antigen expression of CML cells were detected by flow cytometry after over-expression of ITM2A. The nuderlying molecular mechanism of its biological effect was explored. RESULTS: The expression of ITM2A in bone marrow of CML resistant patients was significantly lower than that of sensitive patients and healthy donors（P<0.05）. The CML resistant strain cell K562R was successfully constructed in vitro. The expression of ITM2A in the resistant strain was significantly lower than that in the sensitive strain(P<0.05). Overexpression of ITM2A in K562R cells increased the sensitivity of K562R cells to imatinib and blocked the cell cycle in G2 phase(P<0.05), but did not affect myeloid differentiation. Mechanistically, up-regulation of ITM2A reduced phosphorylation in ERK signaling (P<0.05). CONCLUSION: The expression of ITM2A was low in patients with drug resistance of CML, and the low expression of ITM2A may be the key factor of imatinib resistance in CML.

[Sensitivity of distortion product otoacoustic emissions and auditory brain-stem response in neonatal hearing screening, a comparative study].

OBJECTIVE: To investigate the sensitivity of distortion product otoacoustic emissions (DPOAE) and auditory brain-stem response (ABR) in neonatal hearing screening. METHODS: DPOAE and ABR were conducted on 99 neonates (198 ears) at risk of hearing impairment as initial screening tests. One month later rescreening tests were conducted: DPOAE was conducted again on those ears failing this test during the initial screening test and ABR was conducted again on the ears failing this test during the initial screening test Those ears failing the DPOAE and ABR tests during the rescreening tests were examined with electric otoscope, diagnostic ABR, etc. to get confirmed diagnosis. RESULTS: 54 ears (27%) failed the DPOAE test during the initial screening and 14 out of the 54 ears (14/198, 7%) still failed the DPOAE test during the rescreening. 26 ears (12%) failed the ABR test during the initial screening and 9 out of the 16 ears (9/198, 4.5%) still failed this test during the rescreening. Two babies were confirmed as with severe sensorineural hearing loss, one unilateral and one bilateral. The sensitivity was 97% for DPOAE and 99% for ABR. CONCLUSION: ABR is a little bit more sensitive then DPOAE in neonatal hearing screening. Two-stage testing procedure increases the sensitivity of neonatal hearing screening.