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Biomedical subjects

B Bucher

Publications and source records attributed to B Bucher.

At least 73 records · Page 4Linked to original sources
PubMed1983

Positive practice overcorrection: the effects of duration of positive practice on acquisition and response reduction.

The effects of long and short durations of positive practice overcorrection were studied, for reduction of off-task behavior after an instruction to perform an object-placement task. Off-task behavior, correct responses, and approximate responses were all observed. Off-task behavior received positive practice. The short and long practice durations (30 seconds and 3 minutes) produced equally rapid reduction of off-task behavior and acquisition of correct object-placement performance. Over sessions, much less time was required for positive practice when the short practice duration was used. Approximate responses, which also avoided positive practice, occurred at low rates relative to correct responding. Negative side effects were observed to occur primarily during sessions with long positive practice. These results indicate that use of short durations of positive practice can reduce the practice time required and negative side effects, with no loss of training effectiveness either for reducing inappropriate behavior or increasing a desired alternative behavior.

Adolescent↗
PubMed1983

Neuropharmacological profile of MD 790501, a new benzamide derivative.

Using several classical screening procedures in different species MD 790501: (exo)-2,3 dimethoxy-N-[8-(phenylmethyl)-8-azabiocyclo [3.2.1]oct-3-yl] benzamide hydrochloride was shown to possess potent neuroleptic properties. The doses effective in the tests for neuroleptic activity were similar to or lower than those for heloperidol and clearly lower than those for bromopride, chlorpromazine, sulpiridie, sultopride and thioridazine. Compared with the reference compounds tested MD 790501 showed sedative, cataleptic and dyskinetic effects at doses relatively higher than those effective in tests for neuroleptic activity. MD 790501 possessed no noradrenolytic, anticholinergic, proconvulsant or anxiolytic activity. Its acute toxicity was in the same dose range as that of reference neuroleptics.

Animals↗
PubMed1982

Neuropharmacological profile of MD 780515, a new reversible inhibitor of type A monoamine oxidase.

Using several classical screening procedures, MD 780515, 3-[[4-[5-(methoxymethyl)-2-oxo-3-oxazolidinyl]phenoxy]methyl]- benzonitrile, was shown to possess potential antidepressant activity consistent with preferential and short-acting inhibition of type A monoamine oxidase. The doses effective in the tests for antidepressant activity were much lower than the lethal doses and were similar to or lower than those for reference drugs. MD 780515 showed some anti-convulsant action but had little effect on spontaneous or conditioned behaviour and was devoid of anticholinergic activity.

Animals↗
PubMed1981

Identifying the educative and suppressive effects of positive practice and restitutional overcorrection.

Two major features of the overcorrection procedure, restitution and positive practice, were analyzed for their educative and suppressive properties in the treatment of profoundly retarded adults. Positive practice techniques that were topographically similar and dissimilar to the target behavior were studied. Eating behavior and puzzle performance were observed. Restitutional overcorrection and both forms of positive practice were effective for suppressing inappropriate behaviors. Even when appropriate behaviors had been acquired by positive practice, restitution and dissimilar positive practice were generally ineffective for increasing their rate of occurrence. However, topographically similar positive practice was successful as a means of teaching new appropriate behaviors.

Adult↗
PubMed1980

Peer tutoring with or without home-based reinforcement, for reading remediation.

An operant-based corrective reading program was established to study effectiveness of peer tutoring in the school, for reading deficient children. Sixty-nine second to fourth grade students were matched on measures of initial reading ability and level of reading retardation, and randomly assigned to three groups: Peer Tutoring Only, Peer Tutoring with Home Based Reinforcement, and Control. SRA materials were used in training for the experimental groups, supplemented with additional reading materials. The program continued for 15 weeks, in seven public schools. Changes in oral reading accuracy and comprehansion were assessed. Both reading and comprehension were significantly increased by peer tutoring, relative to the control group. The addition of home-based reinforcement doubled this increase. The measured gain in oral reading, based upon standardized testing, was 0.19 years for the controls and 1.27 years for peer tutoring with home-based reinforcement. Internal measures of gain showed similar results, and comprehension gains were also comparable. A high rate of compliance with the tutoring program was maintained by the tutors. High ratings of satisfaction were obtained for the program, from all groups of participants. The feasibility of the program for application in the school system is discussed.

Achievement↗
PubMed1980

Development of spontaneous manding in language deficient children.

Six institutionalized children, aged 7-11, with little or no spontaneous vocal manding, were trained to request food items under appropriate natural conditions when snacks were presented. "I want a" was appropriate when an adult presented food in the playroom. "Out" was appropriate when the items were displayed in the hallway, across a half-door barrier from the child. A sequence of steps was trained, through increasingly naturalistic setting and cuing conditions. The two mands were trained in sequence, not concurrently. To encourage "spontaneous" productions, no vocal cuing was provided by the adult. After criterion performance in each step, several probe sessions were conducted for various cuing conditions, adults, and settings. Probes after imitation training showed no spontaneous manding. Thus, failure of manding was not due to production difficulties. In probes after training for "approximately" natural cues, most children showed little transfer to the natural cues. This implies that training for the specific appropriate cues may often be required. However, good transfer generally occurred across persons, and from training room to playroom. Probes also showed that most children did not use one of the trained mands in the stimulus conditions that were appropriate for the other mand. Thus, adding a second mand did not generally disrupt use of the first. However, significant disruption occurred for two children. Finally, at the end of training, extinction training was given for one mand in one setting. Performance of the other mand was little affected. In sum, the appropriate form of a mand depends on specific stimulus and setting characteristics, and these characteristics must be considered in training.

Child↗
PubMed1980

Cyclic nucleotide phosphodiesterase in the aorta of spontaneously hypertensive rats : variation with age and effect of propranolol.

The activities of cyclic AMP- and cyclic GMP-phosphodiesterase were studied in the aorta (freed of the adventitia layer) of spontaneously hypertensive rats (SHRs). At the time of weaning (3 weeks of age) young SHRs were separated into two groups. One group was chronically treated with propranolol, 50 mg.kg-1 daily for 4 weeks (treated rats), with treatement beginning either at the time of weaning or at 15 weeks of age. The second group (non-treated SHRs) was used as control. In both groups we observed that the protein content per aorta but not the DNA content increased parallel to the organ weight. The enzyme activities were related to the DNA content of aorta. In non-treated SHRs, the phosphodiesterase activties increased with age, but there was a considerable lag of time between the marked increase in blood pressure that occured between 5 and 12 weeks of age and the increase in phosphodiesterase activity which started after 12 weeks of age. Prolonged propranolol treatment significantly decreased both blood pressure and enzyme activities when started at the time of weaning but had no effect when given to mature SHRs. Thus, the effects of propranolol on blood pressure and on phosphodiesterase activities were associated, whereas no correlation could be established between the age-dependent increases in blood pressure and in phosphodiesterase activities in aorta cells of the SHR.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1980

[Expression of results in studies of vascular biochemical components during the development of the SHR rat].

Hypertrophy and hyperplasia induced by age and hypertension as well as tissue heterogeneity makes it difficult to analyse biochemical datas obtained with rats thoracic aortas from rats of various age and blood pressure. In SHR, the thoracic aorta weight increases parallely to the body weight from the first week after birth onwards. Meanwhile the protein content of the organ increases parallely to the organ weight. However, though the DNA content increases markedly up to 7 weeks of age, one observes a much lower increase with age afterwards. It seemed to us that the aorta DNA content was more representative of the organ cell number. This led us to use express our biochemical data per mg of the organ DNA content. Moreover, it seems necessary to take in account the cell volume which increases as well with age and hypertension on the one hand, and to be able to distinguish the cellular content of the myocytes from the one of other cells types contained in the adventitia and the intima, on the other hand. For these purposes pure media layers are prepared by completely removing the adventitia and intima and single cell suspensions are obtained after total enzyme digestion of the medias.

Age Factors↗
PubMed1978

Adrenergic and dopaminergic control of growth hormone secretion in urethan anesthetized adult male rats.

The effects of drugs which interfere with alpha-adrenergic and dopaminergic mechanisms, involved in GH and PRL secretion, have been analyzed in urethane anesthetized rats. Clonidine induced a dose-dependent release of GH (0.0032--0.1 mg/kg i.v.) as well as of PRL (0.032--1.0 mg/kg i.v.). The lowest dose of clonidine, when given into the third ventricle, provoked a very pronounced release of GH. Phentolamine, given intravenously, inhibited the clonidine-induced GH release in a dose-dependnet manner. L-Dopa administered intravenously and apomorphine administered intravenously or intraventricularly did not affect basal secretion of GH bu- produced a dose-dependnet inhibition of clonidine-induced GH release. Pimozide did not change basal GH secretion. Furthermore pimozide did not attenuate the inhibition of clonidine-induced GH secretion seen after apomorphine administration, however, it completely reversed apomorphine-induced PRL inhibition. These findings demonstrate that an alpha-adrenoceptor-mediated stimulatory mechanism is involved in GH and PRL secretion. An inhibitory dopaminergic mechanism is confirmed for PRL secretion and suggested for GH secretion.

Animals↗
PubMed1976

Alpha adrenergic control of growth hormone in adult male rats.

Intravenous injection of 0.1 mg/kg clonidine into rats under urethane anaesthesia induced a prompt and long-lasting release of growth hormone, estimated by radioimmunoassay (IRGH), which could be abolished by 0.2 mg/kg phentolamine given into the 3rd ventricle. Injection of 3 mug/kg clonidine into the 3rd ventricle stimulated also the release of IRGH significantly. Intravenous administration of 0.32 mg/kg phenylephrine caused a small and transient release of IRGH only. These results provide evidence that central alpha-adrenergic stimulation resulting in an increased GH secretion is one important mechanism in the regulation of this hormone in the rat.

Animals↗