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Biomedical subjects

M S Rosenbaum

Publications and source records attributed to M S Rosenbaum.

7 recordsLinked to original sources
PubMed1991

Immediate reproducibility of electrically induced sustained monomorphic ventricular tachycardia before and during antiarrhythmic therapy.

The immediate reproducibility of sustained ventricular tachycardia induction was evaluated prospectively during 106 studies performed in 53 patients with clinical sustained monomorphic ventricular tachycardia. Programmed electrical stimulation was performed twice, using the same protocol during 53 drug-free studies and 53 subsequent studies on antiarrhythmic therapy. Sustained monomorphic ventricular tachycardia was reproduced in 104 (98%) of the 106 studies. There was no significant difference in the incidence of reproducible tachycardia in the drug-free state compared with that observed during treatment with different classes of antiarrhythmic drugs. An increase in the number of extrastimuli was required to reinitiate the tachycardia in 9 (11%) of 83 studies in which single or double extrastimuli were initially required to induce the tachycardia. In 39 (37%) of 104 studies with reproducible tachycardia induction, the two tachycardias significantly differed in electrocardiographic (ECG) configuration and cycle length. These observations suggest that the overall reproducibility of ventricular tachycardia induction is sufficiently high to provide a reliable marker for evaluating the efficacy of therapeutic interventions. However, specific tachycardia characteristics such as cycle length and ECG configuration are more variable even within the same study and may be less useful in assessing the effects of subsequent interventions.

Anti-Arrhythmia Agents↗
PubMed1987

A nonendocytotic mechanism for the selective uptake of high density lipoprotein-associated cholesterol esters.

We have previously described in rats the selective uptake of HDL-associated cholesterol esters (traced by [3H]cholesteryl oleyl ether) in excess of the uptake of HDL-associated apoA-I. In the present studies we show that the mechanism also exists in cultured cells of human and mouse origin as well. This selective uptake represents a net uptake of cholesterol esters and not an isotope exchange, as shown by mass flux studies in adrenal cells. Inhibitors of receptor recycling, chloroquine, monensin, and colchicine, inhibited uptake of apoA-I from HDL by Hep G-2 human hepatoma cells to about the same extent as a reference protein, asialofetuin, but inhibited uptake of the cholesteryl ether tracer much less. Levels of NaN3 which effectively inhibited sucrose pinocytosis inhibited uptake of apoA-I to about the same extent but did not inhibit uptake of the cholesteryl ether at all. Thus, not only receptor recycling, but endocytosis as well, appears not to be involved in selective uptake. This conclusion was supported by studies in which synthetic HDL particles were made to contain two neutral lipid core tracers; one of them, the [3H]cholesteryl ether previously used, was selectively taken up, whereas the other, [14C]sucrose octaoleate, was excluded from selective uptake. Thus, selective uptake cannot involve endocytosis of the entire lipid core, but may involve other specific transfer mechanisms.

Adrenal Cortex Neoplasms↗
PubMed1983

Applicability of the Denver Prescreening Developmental Questionnaire in a low-income population.

A prospective study was conducted to assess the applicability of the Denver Prescreening Developmental Questionnaire (DPDQ) in a predominantly black, low-income population in Mobile, Alabama. The effect of an educational intervention designed to increase the accuracy of parental responses to the DPDQ was also assessed. In a longitudinal follow-up program, 127 infants aged 2 weeks to 1 year were recruited. Parents in a randomly selected experimental group observed an audio-visual presentation describing progressive developmental behaviors, received handout materials summarizing these behaviors, and were asked to record their child's subsequent attainment of these behaviors. Mean agreement scores, obtained by comparing parental responses to the DPDQ with the corresponding items of the Denver Developmental Screening Test (DDST), did not differ between the experimental and control groups. These scores showed agreement of 93.6% (3-month visit), 91.3% (6-month visit), 91.6% (9-month visit), and 95.1% (12-month visit), resulting in an overall mean agreement score of 92.9%. The overreferral rate was low (13%) and no underreferrals were obtained. These results attest to the applicability of the DPDQ in low-income population and demonstrate the lack of effectiveness of the educational intervention in increasing the accuracy of parental responses to the DPDQ.

Adolescent↗
PubMed1979

Self-control training in the classroom: a review and critique.

Self-control training in classroom settings is becoming widespread. Establishing effective self- rather than externally controlled behavior modification programs in schools would enable children to control their own academic and social behavior, while enabling teachers to devote more time to teaching. The following components of self-control are reviewed in the present article: self-recording, self-evaluation, self-determination of contingencies, and self-instruction. Self-control strategies designed for the maintenance of appropriate classroom behavior, and issues associated with self-control training, such as the reliability of self-observation, response maintenance, generalization, and the role of external control, are examined. Finally, suggestions for maximizing the potential effectiveness of self-control training in the classroom (e.g., teaching self-observational procedures, teaching students to provide themselves with instructions and praise), as well as future areas for experimental investigation (e.g., social changes that may be associated with self-control procedures), are presented.

Adolescent↗
PubMed1976

The development and functional control of reading-comprehension behavior.

Reading comprehension, indicated by motor behavior and multiple-choice picture selection called for in written instructions, was taught to an autistic child using verbal prompts, modelling, and physical guidance. The child was rewarded for correct behaviors to training items; nonrewarded probes were used to assess generalization. Probable maintaining events were assessed through their sequential removal in a reversal design. Results showed: (a) following acquisition, performance was maintained at a near-100% level when candy, praise, attention, and training were removed, (b) absence of other persons was correlated with a marked decrease in performance, whereas their presence was associated with performance at near 100%, and (c) performance generalized to probes and across experimenters. Rewards, which may have been reinforcing during acquisition, did not appear necessary to maintain later performance. Instead, presence of others (a setting event) was demonstrated to have control over maintained performance.

Autistic Disorder↗