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Biomedical subjects

D A Daly

Publications and source records attributed to D A Daly.

15 recordsLinked to original sources
PubMed1993

Actions of clozapine and haloperidol on the extracellular levels of excitatory amino acids in the prefrontal cortex and striatum of conscious rats.

The technique of intracerebral microdialysis was employed to assess the effect of acute clozapine and haloperidol on the extracellular levels of aspartate and glutamate in the striatum and medial prefrontal cortex of conscious rats. Subcutaneous injection of 25 mg/kg clozapine, but not the lower dose of 15 mg/kg, led to a significant increase in both aspartate and glutamate levels over time. The maximum effect was observed two hours after injection. Haloperidol (0.5 and 1 mg/kg s.c.) did not increase the extracellular levels of aspartate and glutamate over time. At all doses tested, both drugs were without a significant effect in the striatum. These data suggest that clozapine may have selective actions on the cortical excitatory amino acid systems.

Animals↗
PubMed1993

Distinct actions of endogenous excitatory amino acids on the outflow of dopamine in the nucleus accumbens.

Intracerebral microdialysis was utilized to assess the effect of endogenous excitatory amino acids (EAA), l-glutamate (GLU) and l-aspartate (ASP), on the extracellular levels of dopamine in the rat nucleus accumbens. Both ASP and GLU produced a release response at a concentration range of 1 to 10 mM. GLU was generally less efficacious in increasing dopamine outflow; at 5 and 10 mM, the maximum effect exerted by GLU was significantly less than that observed with ASP. The specific N-methyl-D-aspartate (NMDA) antagonist 2-amino-5-phosphonopentanoic (AP5) acid was more effective in attenuating the actions of 5 and 10 mM ASP than the non-NMDA antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). On the other hand, the stimulatory actions of 5 and 10 mM GLU were more effectively decreased with CNQX when compared with AP5. Perfusion of tetrodotoxin before application of either GLU or ASP blocked the excitatory effect of these amino acids on dopamine overflow. These results suggest that in the nucleus accumbens, ASP and GLU may increase dopamine release through distinct mechanisms and that their stimulatory action is dependent on axonal impulse flow.

Amino Acids↗
PubMed1978

Elicited imitation in language assessment: a tool for formulating and evaluating treatment programs.

Four different clinical populations were administered an elicited imitation task before and after therapy to determine the usefulness of elicited imitation procedures for formulating and evaluating language treatment programs. Children's imitations were analyzed according to the numbers and patterns of omission errors, substitution errors, and correct responses. Results indicated that (1) patterns of responding could be identified; (2) specific patterns were associated with different clinical populations; (3) performance on pretherapy measures could be efficiently analyzed and utilized for formulating language treatment programs; and (4) changes in posttherapy performance could be readily evaluated using this procedure. The data suggest that the elicited imitation procedures can be effectively used to increase the precision of the evaluation and clinical programming of children with language disorders.

Adolescent↗
PubMed1978

Stuttering as operant behavior: effects of the verbal stimuli wrong, right, and tree on the disfluency rates of school-age stutterers and nonstutterers.

This study assessed the effects of the verbally presented stimuli wrong, right, and tree on the frequency of disfluencies during oral reading by 18 school-aged stutterers and 18 matched nonstutterers. No differences were found between the three stimulus words' effect on the disfluency rate of either subject group. Because decreases in the disfluency rates of stutterers were observed during the presentation of all three stimulus words, the data failed to support the operant model. A discussion of theoretical and experimental implications is given.

Adolescent↗
PubMed1977

Bioelectronic measurement of nasality in trainable mentally retarded children.

Fifty trainable mentally retarded children were evaluated with TONAR II, a bioelectronic instrument for detecting and quantitatively measuring voice parameters. Results indicated that one-half of the children tested were hypernasal. The strikingly high prevalence of excessive nasality was contrasted with results obtained from 64 nonretarded children and 50 educable retarded children tested with the same instrument. The study demonstrated the need of retarded persons for improved voice and resonance.

Adolescent↗
PubMed1976

Nasalance in utterances of hearing-impaired speakers.

Instrumental comparisons of sound from the nose and mouth expressed in percent nasalance, articulation errors, and speech rate are used in this study to contrast utterances of 50 speakers with severe hearing impairment and 64 with normal hearing. Results of the study revealed that 54% of the hearing-impaired subjects had nasalance ratio scores greater than two standard deviations above the mean of the group with normal auditory acuity. No general relationship was found between the number or type of articulation errors and the nasalance scores. Rate of speaking was significantly related to the nasalance scores of the normal group but not those of the hearing-impaired group. Tonagrams displaying the variations in nasalance revealed small, 1 to 50% spike-shaped fluctuations in the displays of the utterances from both groups. Additional prolonged bursts of nasalance in excess of a 30% change in the ratio between the nasal and oral signal were common in the displays from the hearing-impaired group did not in those of the group with normal acuity. Possible sources and perceptual effects of these phenomena are discussed.

Adolescent↗