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51.
Effects of age and age-related hearing loss on the neural representation of speech cues. 总被引:6,自引:0,他引:6
OBJECTIVE: To examine the effects of aging and age-related hearing loss on the perception and neural representation of a time-varying speech cue. METHODS: P1, N1 and P2 cortical responses were recorded from younger and older normal-hearing adults, as well as older adults with age-related hearing loss. Synthetic speech tokens representing 10 ms increments along a /ba/-/pa/ voice-onset-time (VOT) continuum were used to evoke the responses. Each participant's ability to discriminate the speech tokens was also assessed. RESULTS: Compared with younger participants, older adults with and without hearing loss had more difficulty discriminating 10 ms VOT contrasts. In addition, both older groups elicited abnormal neural response patterns. There were no significant age-related findings for P1 latency; however, N1 latencies were prolonged for both older groups in response to stimuli with increased VOT durations. Also, P2 latencies were delayed for both older groups. The presence of age-related hearing loss resulted in a significant increase in N1 amplitude in response to voiceless stimuli. CONCLUSIONS: Aging and age-related hearing loss alter temporal response properties in the central auditory system. Because both older groups had difficulty discriminating these same speech stimuli, we conclude that some of the perceptual difficulties described by older adults might be due to age-related changes regulating excitatory and inhibitory processes. SIGNIFICANCE: Some of the speech understanding difficulties expressed by elderly adults may be related to impaired temporal precision in the aging auditory system. This might explain why older adults frequently complain that wearing a hearing aid makes speech louder, but does not necessarily improve their ability to understand speech. 相似文献
52.
Gérald Vanzetto Marc Janier Daniel Fagret Luc Cinotti Xavier André-Fouet Michel Comet Jacques Machecourt 《European journal of nuclear medicine and molecular imaging》1997,24(2):170-178
The best test presently available to ascertain residual viability within an infarct-related area involves the use of fluorine-18
fluorodeoxyglucose (FDG) to detect the persistence of some cellular metabolism. Rest reinjection of thallium-201 is a less
accurate alternative but is easy to perform. Iodinated fatty acids, which are used with standard gamma cameras, are proposed
as markers of cellular metabolism. This study was performed to assess the value of 16-iodo-3-methyl-hexadecanoic acid (MIHA)
as a marker of the residual cellular metabolism by comparison with FDG in patients with a recent myocardial infarction, and
to evaluate its contribution compared with the201Tl stress-redistribution-reinjection technique. Stress-redistribution-reinjection201T1 imaging, rest MIHA imaging and glucoseloaded FDG imaging were performed in 22 patients with recent myocardial infarction.
Out of the 628 myocardial segments obtained from the left ventricular analysis, 400 were hypoperfused (relative uptake <0.75
of maximum uptake on stress201T1 imaging), 177 of which were severely hypoperfused (relative uptake <0.50). Receiver operating characteristic (ROC) curves
for predicting metabolic myocardial viability with FDG were derived from the results in respect of (a)201T1 activity during exercise, redistribution and reinjection and (b) MIHA up-take, using the two FDG thresholds most commonly
considered to define metabolic viability (0.50 and 0.60). Analysis of the 400 hypoperfused segments demonstrated that201T1 reinjection was the most accurate test in predicting the presence of myocardial viability (area under the ROI curves=0.85
and 0.86 at the 0.50 and 0.60 FDG thresholds, respectively;P<0.05 vs other tests). The global predictive values of MIHA and201T1 reinjection were, respectively, 0.87 and 0.89 at the 0.50 FDG threshold (NS), and 0.82 and 0.87 at the 0.60 FDG threshold
(NS). When only the 177 severely hypoperfused segments were considered,201T1 reinjection remained the most accurate test (accuracy 0.84 at the 0.50 FDG threshold and 0.82 at the 0.60 FDG threshold),
while the accuracy of MIHA decreased significantly (0.78 at the 0.50 FDG threshold and 0.73 at the 0.60 FDG threshold,P<0.05 vs201T1 reinjection). In all circumstances, MIHA was less specific than201T1 reinjection for the detection of metabolic viability. In conclusion, in patients with recent myocardial infarction, MIHA
accurately detects the persistence of metabolic viability, but is not superior to201T1. 相似文献
53.
54.
Caroline Hartmann Hervé Récipon Marie-France Jubier Christiane Valon Evelyne Delcher-Besin Yves Henry Jacques De Buyser Bernard Lejeune André Rode 《Current genetics》1994,25(5):456-464
The mitochondrial genome of the selfed progeny of a plant regenerated from long-term somatic tissue culture displays specific structural rearrangements characterized by the appearance of novel restriction fragments. A mitochondrial DNA library was constructed from this selfed progeny in the SalI site of cosmid pHC79 and the novel fragments were subsequently studied. They were shown to arise from reciprocal recombination events involving DNA sequences present in the parental plant. The regions of recombination were sequenced and the nucleotide sequences were aligned with those of the presumptive parental fragments. We characterized an imperfect short repeated DNA sequence, 242 bp long, within which a 7-bb DNA repeat could act as a region of recombination. The use of PCR technology allowed us to show that these fragments were present in both parental plants and tissue cultures as low-abundance sequence arrangements. 相似文献
55.
A. Newman-Tancredi V. Audinot V. Jacques J. L. Peglion M. J. Millan 《Neuropharmacology》1995,34(12):1693-1696
The selective dopamine D3 receptor antagonist [3H](+)S 14297 ((+)-[7-(N,N-dipropylamino)-5,6,7,8-tetrahydro-naphtho(2,3b)dihydro,2,3-furane]), labelled to high specific activity (145 Ci/mmol), bound to cloned human dopamine D3 receptors but displayed negligible binding to cloned human D2 receptors. [3H](+)S 14297 exhibited rapid association and dissociation, high affinity saturable binding (Kd = 7.0 nM) and a competition binding profile highly correlated with that of [125I]iodosulpride (r = 0.98). 相似文献
56.
57.
Benoit J. M. Pirotte Alphonse Lubansu Michael Bruneau Chakir Loqa Nathalie Van Cutsem Jacques Brotchi 《Child's nervous system》2007,23(11):1251-1261
Objective The objective of this study was to evaluate whether the rigid application of a sterile protocol for shunt placement was applicable
on a routine basis and allowed the reduction of shunt infections (SI) in children.
Materials and methods Since 2001, a rigid sterile protocol for shunt placement in children using neither antibiotic-impregnated catheters nor laminar
airflow was prospectively applied at Erasme Hospital, Brussels, Belgium. For assessing the protocol efficacy before continuation,
we preliminarily analyzed the results of the first 100 operated children (43 females, 57 males, 49 aged <12 months; 115 consecutive
shunt placement/revision procedures). All procedures were performed by the same senior surgeon, one assistant, one circulating
nurse, one anesthesiologist. The sterile protocol was rigidly imposed to these four staff members: uniformed surgical technique;
limited implant and skin edge manipulation; minimized human circulation in the room; scheduling surgery as first morning operation;
avoiding postoperative cerebrospinal fluid (CSF) leak; double gloving; procedures of less than 30-min duration; systemic antibiotics
prophylaxis. We analyzed separately: (1) children carrying an increased risk of SI (n = 38) due to preoperative external ventricular drainage, CSF leak, meningitis, glucocorticoids, chemotherapy; (2) children
aged <12 months; (3) procedures for shunt revision.
Results Errors in protocol application were recorded in 71/115 procedures. They were mainly done by non-surgical staff, decreased
with time and were medically justified in some young children. Surprisingly, no SI occurred (follow-up, 4 to 70 months). One
child developed an appendicitis with peritonitis (Streptococcus faecalis) after 6 months. No SI was found. After peritonitis was cured, shunt reinsertion was uneventful.
Conclusion These preliminary results suggest that a uniform and drastic sterile surgical technique for shunt placement: (1) can be rigidly
applied on a routine basis; (2) can lower the early SI rate below 1%; (3) might have a stronger impact to reduce SI than using
antibiotic-impregnated catheters and optimizing the operative environment such as using laminar airflow and reducing the non-surgical
staff. This last issue will be evaluated further in the present ongoing protocol. 相似文献
58.
59.
Aureo L DePaula Antonio L V Macedo Claudio R Cernea Vladimir Schraibman Jacques Pinus José R Milanez José E Succi Flávio C Hojaij Dorival de Carlucci Sunao Nishio 《Otolaryngology--head and neck surgery》2006,135(5):710-713
BACKGROUND: Gastric pull-up is a useful method for reconstruction of the upper digestive tract, with considerable morbidity/mortality, especially in esophageal cancers (EC). OBJECTIVE: To analyze the experience of a multidisciplinary team with a laparoscopic gastric pull-up (LGPU) method, with or without thoracoscopy, in a series of 120 patients with EC. STUDY DESIGN: Retrospective. PATIENTS AND METHODS: From 1992 to 2004, 120 EC [cervical/cervicothoracic (3.0%), middle third (15.0%), and inferior third (82.0%)]. Most were squamous cell carcinomas (47.0%) and adenocarcinomas (34.0%). Stomach was dissected and mobilized exclusively by laparoscopy. Occasionally, laparoscopic approach was extended cranially, until connecting with cervical dissection. In other cases, dissection of thoracic esophagus was accomplished through a thoracoscopic approach. RESULTS: Eighty-one patients (68.0%) had LGPU; 39 (32.0%) needed thoracoscopy. Mortality was 5.9%. Complications were fistula (10.0%) and pneumonia (10.0%). All fistulae closed spontaneously; 89.2% of patients could swallow a normal oral diet. CONCLUSION: Low morbidity/mortality of LGPU for EC compared favorably with conventional techniques. 相似文献
60.
Helen E. Savaki Jean-Antoine Girault Umberto Spampinato Ngog-An Truong Jacques Glowinski Marie-Jo Besson 《Brain research bulletin》1986,16(2)
The release of newly synthesized 3H-dopamine (3H-DA) was measured in the rat striatum superfused, through a push-pull cannula, with a physiological medium enriched in 3H-tyrosine. The level of spontaneous 3H-DA release was dependent on the topographical localisation of the cannula in the striatum (anterior parts displayed higher levels than posterior ones) and on the anesthetic state (halothane anesthetized rats demonstrated higher levels than awake ones). Inhibition of DA inactivation processes by local application of benztropine (a DA reuptake inhibitor, 10−6 M) or by IV administration of pargyline (a MAO inhibitor, 100 mg/kg) enhanced the detectable outflow of 3H-DA from the striatum in both halothane anesthetized and awake rats. Local application of D-amphetamine (10−5 M) or acetylcholine (5 × 10−5 M) in the presence of eserine (5 × 10−5 M) evoked respectively a fivefold and a 30% increase in spontaneous 3H-DA release in halothane anesthetized rats. Inhibition of the firing of dopaminergic neurons by IV injection of gamma-hydroxybutyrate (400 mg/kg) produced a 30% decrease in striatal 3H-DA release. The present results demonstrate that the push-pull cannula method is suitable for the study of DA release in both the anesthetized and the awake rat. 相似文献