RESUMO
Quinine reversibly affects the outer hair cells (OHC). It is therefore an ideal drug for studying OHC-related phenomena, such as transient evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs). Pure-tone thresholds (PTTs), 1,000-4,000 Hz, TEOAEs, and DPOAEs were measured monaurally in 5 normal-hearing volunteers during quinine administration. DPOAE was evoked at 75 dB SPL (f2/f1 = 1.22) and analysed at 2f1-f2 with f2 at 6 frequencies (700-4,000 Hz), while TEOAE was obtained at 79 dB SPLp and analysed at the f2 frequencies (1/3 octave). The PTT-shift was flat, 10 dB, whereas the TEOAE-power and the global mean of the DPOAEs decreased 4.5 dB and 1.4 dB, respectively. No correlation was found between the intra-individual emission shifts. It is concluded that TEOAE is more sensitive than high-level DPOAE for identifying minor cochlear hearing losses. Support is given to the hypothesis that different sources are involved in generating DPOAEs at different evoking levels.
Assuntos
Células Ciliadas Auditivas/efeitos dos fármacos , Quinina/farmacologia , Estimulação Acústica , Adulto , Audiometria de Tons Puros , Limiar Auditivo , Orelha Interna/efeitos dos fármacos , Feminino , Transtornos da Audição/induzido quimicamente , Transtornos da Audição/diagnóstico , Humanos , Espectrografia do SomRESUMO
In the process of prosthetic loosening, the initial motion of the implant relative to the bone is a key element. In order to provide quantitative information, three straight and one curved cementless hip stems were submitted to in vitro tests in autopsy specimens of the femur under dynamic axial and torsional loads with the displacements measured in several directions. The results were compared to those of an additional group of cemented straight stem prostheses providing reference values. Subsidence of cementless implants on the average was significantly higher than the cemented reference, but single implants were comparable to the reference. Rotational motion was distinctly higher than the reference values, with considerable differences between designs. When comparing displacements perpendicular to the main load direction, the sagittal plane motion was found to be at least double the motion in the frontal plane. Micromotions at the prosthesis/bone interfaces under the load case selected were smallest for the curved and highest for one of the straight prostheses.