Biomedical subjects

C Giguere

Publications and source records attributed to C Giguere.

4 recordsLinked to original sources

PubMed2000

Increased expression of major basic protein (MBP) and interleukin-5(IL-5) in middle ear biopsy specimens from atopic patients with persistent otitis media with effusion.

BACKGROUND: Molecular biologic evidence to support an etiologic role for allergy in the pathogenesis of persistent otitis media with effusion (OME) is lacking. OBJECTIVE: The goal of this article was to document expression of allergy-associated Th-2-type cytokines and inflammatory cells in the middle ear mucosa of children with persistent OME. METHODS: With immunocytochemistry (CD3, major basic protein) and in situ hybridization (interleukin-5 mRNA), middle ear biopsy specimens from 7 children with persistent OME were stained. Nonatopic stapedectomy patients with no history of otitis media served as controls (n = 7). RESULTS: There was a statistically significant (P< 0.05) difference in expression of CD3, major basic protein, and interleukin-5 between experimental and control subjects. All 8 OME patients proved to be atopic by ELISA testing. CONCLUSIONS: Type I allergy involving a Th-2-type cytokine and cellular profile may be a contributing factor in the persistence of OME in atopic children. SIGNIFICANCE: The middle ear may serve as a target organ for allergic inflammation, suggesting that appropriate allergy management may be a useful adjunct to the management of OME.

Biopsy↗

PubMed1991

Signal detection and speech perception with level-dependent hearing protectors.

An experiment was conducted to investigate signal detection and speech perception with level-dependent hearing protectors. Twenty normal-hearing young adults participated in the first phase of this program, the ultimate objective of which was an assessment of the effect of hearing loss. For each subject, measurements were made of the detection of one-third octave noise bands centered at 500, 1000, 2000 and 4000 Hz, consonant discrimination, and word recognition. Performance on these tests was evaluated in quiet and in a background of 75 dB SPL cable swager noise, with the ears unoccluded and protected with four different muffs. The devices selected were the E-A-R 9000 and BILSOM 2390 and their conventional level-independent counterparts, the E-A-R 3000 and BILSOM 2315. The results indicated that signal detection in noise generally remained the same or was slightly enhanced when the protectors were worn. For consonant discrimination, there were no differences among the various protectors in quiet, while in noise the wearing of the BILSOM 2390 resulted in a significant decrement in the intelligibility of the initial consonant. For word recognition, the BILSOM 2390 resulted in an advantage in quiet, particularly for sentences with low contextual cues. The reverse effect was true in noise. The results obtained for the E-A-R 9000 were similar to those for the two conventional HPDs.

Acoustics↗

PubMed1990

Stimulus parameters in detection and reaction time.

This paper describes the relationship between detection threshold and reaction time for pure tones presented within the context of a two-interval forced-choice signal detection paradigm. Three variables manipulated were stimulus frequency (500 and 4,000 Hz), duration (50 and 300 ms) and rise/decay time for the longer stimulus (10 and 100 ms). The data for three practised, normal-hearing subjects indicated that stimulus energy was a good predictor of the detection threshold. Threshold measurements decreased as a function of the increase in stimulus duration and the decrease in rise/decay time. Both correct and incorrect reaction times also decreased with the increase in duration but were insensitive to a change in rise/decay time. The non-monotonicity of the function relating threshold and reaction time, as well as wide differences in reaction time for the same level of hearing acuity across subjects, led to the major conclusion that the two psychophysical measures were not interchangeable.

Adult↗

PubMed1989

Role of probe tone parameters in frequency selectivity for normal listeners.

The objective of this research was a determination of the role of probe tone parameters in frequency selectivity. Frequency selectivity is the ability of the auditory system to analyze a complex sound into its frequency components, and is typically evaluated by measuring the psychophysical tuning curve. Generally this entails documenting the effect of varying the center frequency of a narrowband noise masker for a given pure tone probe, 10 dB above threshold. In the present study, a new approach was taken. A family of tuning curves were generated for a series of tone probes which differed in frequency, duration and intensity, but which remained constant in energy. The results for three normal-hearing subjects indicated that the critical parameter for the shape of the tuning curve was the energy of the probe. Decreasing the energy below values generally tested resulted in aberrant shapes across subjects, which bore some resemblance to those documented in hearing-impaired listeners. Temporal summation was suggested as the unifying principle.

Acoustic Stimulation↗