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Biomedical subjects

J Northup

Publications and source records attributed to J Northup.

At least 19 recordsLinked to original sources
PubMed2001

The influence of a token economy and methylphenidate on attentive and disruptive behavior during sports with ADHD-diagnosed children.

Three children diagnosed with attention deficit hyperactivity disorder (ADHD) participated in a summer program designed to evaluate the influence of stimulant medication and a token economy on attentive and disruptive behavior during kickball games. Attentive and disruptive behavior were assessed using an interval coding system, and daily ratings on the ADHD Index of the Conners Teacher Rating Scale-Revised were also obtained. A multielement reversal design was used, and the results indicated that both interventions independently improved attentive behavior and decreased disruptive behavior for the participants. Contrary to other research, when the token economy and medication were compared in isolation, the token system appeared more effective in reducing disruptive behavior for 2 of the 3 participants. In addition, the token system generally enhanced the effects of stimulant medication.

Attention Deficit Disorder with Hyperactivity↗
PubMed2000

Further evaluation of the accuracy of reinforcer surveys: a systematic replication.

The present report evaluates the accuracy of a reinforcer survey by comparing the survey results to the results of subsequent reinforcer assessments for 20 children using a concurrent-operants arrangement to assess relative reinforcer preference. Total accuracy for the survey was determined to be approximately 57%. The results provide a systematic replication of Northup et al. (1996) with a much larger sample of children. A need for the development of more accurate and comprehensive reinforcer assessment methods for verbal children is discussed.

Attention Deficit Disorder with Hyperactivity↗
PubMed2000

Two amino acids in the sixth transmembrane segment of the mouse gastrin-releasing peptide receptor are important for receptor activation.

The gastrin-releasing peptide receptor (GRP-R) is a G protein-coupled receptor that mediates a variety of cellular responses, including cell growth and modulation of neuronal activity by activation of heterotrimeric GTP-binding proteins in the Gq family. To understand the regulation of GRP-R signaling we have substituted alanine for each of 10 amino acid residues within the transmembrane (TM) helices of the GRP-R predicted to project into the binding pocket of the receptor and analyzed the importance of each of these residues for receptor function. Two mutations showed selective loss of either agonist (Y285A) or antagonist (F313A) affinity for the GRP-R. In addition, we identified two amino acid residues, Phe(270) and Asn(281), in the sixth TM segment, which are important for receptor-G protein interaction. In a competition-binding assay with an antagonist radioligand, bombesin showed a 20- to 100-fold decreased affinity for the N281A and F270A mutant GRP-R compared with wild-type GRP-R. The saturation-binding isotherms are best fit by a two-state model, indicating that the receptors are in either a low-affinity (K(D2)) or a high-affinity (K(D1)) state. The ratio of the two affinities (K(D2)/K(D1)) was significantly increased for both mutants compared with wild-type GRP-R, whereas the fraction of mutant receptors in the high-affinity state (R(1)) was decreased. GDP/guanosine-5'-O-(3-thio)triphosphate exchange catalyzed by the N281A mutant was lower than that observed for the wild-type GRP-R. However, for both mutants, bombesin was still able to stimulate 1,4,5-inositol triphosphate in transfected cells albeit with reduced activity. We conclude that these two TM residues are important for receptor-G protein coupling, and postulate that each mutation may affect GRP-R conformational change to the high-affinity, G protein-coupled state.

3T3 Cells↗
PubMed1999

Further analysis of the separate and interactive effects of methylphenidate and common classroom contingencies.

We evaluated separate and interactive effects between common classroom contingencies and methylphenidate (MPH) on disruptive and off-task behaviors for 4 children with a diagnosis of attention deficit hyperactivity disorder. Analogue conditions consisting of contingent teacher reprimands, brief time-out, no interaction, and alone were conducted in a multielement design. Medication status (MPH or placebo) was alternated across days in a superordinate multielement design. Results indicate that (a) the behavioral effects of MPH were influenced by one or more of the analogue conditions for each participant, and (b) time-out was associated with zero or near-zero levels of both disruptive and off-task behavior for 3 of the 4 participants during MPH and placebo conditions. Implications for the clinical effectiveness of MPH and possible behavioral mechanisms of action of MPH in applied settings are discussed.

Achievement↗
PubMed1998

Effects of contingent reward and instruction on oral reading performance at differing levels of passage difficulty.

This study examined the effects of reinforcement contingencies designed to increase the performance of existing reading skills as well as the effects of instruction--modeling and practice--designed to increase skill level for oral reading fluency across three levels of reading materials. Results showed that a combination of contingencies, modeling, and practice was effective in producing substantial increases in reading fluency for all participants at their assigned grade levels. These results demonstrate one strategy for experimentally determining those instructional components that are required to increase oral reading rate.

Child↗
PubMed1997

A preliminary analysis of interactive effects between common classroom contingencies and methylphenidate.

To assess the drug-behavior interaction effects with an 8-year-old boy wih attention deficit hyperactivity disorder, common classroom antecedent (e.g., seating arrangement) and consequent (e.g., peer prompts) stimuli were alternated within a school day while drug conditions (methylphenidate vs. placebo) were alternated across days. The results suggested that peer attention maintained disruptive behavior when methylphenidate was absent but not when it was present.

Attention Deficit Disorder with Hyperactivity↗
PubMed1997

An evaluation of methylphenidate as a potential establishing operation for some common classroom reinforcers.

We conducted reinforcer assessments for 3 boys with a diagnosis of attention deficit hyperactivity disorder who alternately received either placebo or previously prescribed methylphenidate. Our purpose was to evaluate whether methylphenidate altered the relative reinforcing effectiveness of various stimuli that are often used in classroom-based behavioral treatment programs (e.g., activities, tangible items). Results showed clear differences for some stimuli between reinforcer assessments conducted when participants had received methylphenidate compared to placebo. Results suggest that methylphenidate might act as an establishing operation for some common classroom reinforcers. Implications for the development and evaluation of behavioral treatments are discussed.

Attention Deficit Disorder with Hyperactivity↗
PubMed1997

Comprehensive school-based behavioral assessment of the effects of methylphenidate.

Individualized assessments of the effects of three doses of methylphenidate (MPH) were conducted for 2 students with attention deficit hyperactivity disorder within each child's classroom using behavioral, academic, and social measures. A double-blind, placebo-controlled, multielement design was used to evaluate the results. Results suggested that at least one or more dosages of MPH were associated with some degree of improvement for both children in each area of functioning as compared to placebo. However, the degree of improvement at times varied substantially across dosage and area of functioning. Results suggest that MPH dosage and area of child functioning are critical assessment parameters and that controlled clinical trials are necessary to optimize the effectiveness of treatment with MPH for the individual child.

Attention Deficit Disorder with Hyperactivity↗
PubMed1996

A comparison of reinforcer assessment methods: the utility of verbal and pictorial choice procedures.

We compared three methods of stimulus preference assessment for verbal children and specifically evaluated the utility of a verbal choice procedure for assessing relative reinforcer value. Using a token system, relative preference for five categories of reinforcers, representing 15 different stimuli, was assessed by three methods: a reinforcer survey, a verbal stimulus-choice questionnaire, and a pictorial stimulus-choice procedure. Results showed that the verbal and pictorial stimulus-choice assessments accurately identified high- and low-preference categories for 3 of 4 participants. Survey results alone often rated multiple categories as high preference, were less likely to identify low-preference categories, and were less likely to correspond with the results of a reinforcer assessment.

Attention Deficit Disorder with Hyperactivity↗
PubMed1995

A preliminary comparison of reinforcer assessment methods for children with attention deficit hyperactivity disorder.

We evaluated the relative treatment utility of a verbal forced-choice questionnaire, child nomination, and direct observation for identifying the most potent reinforcers for children with attention deficit hyperactivity disorder. Results demonstrated that all three methods were more likely to disagree than to agree, that a forced-choice format may enhance verbal reinforcer assessment, and that further development and evaluation of verbal reinforcer-assessment methods are needed.

Attention Deficit Disorder with Hyperactivity↗
PubMed1994

Potential problems in using [35S]-dATP-tailed oligonucleotides for detecting mRNAs in certain cells of the immune system.

In this study we examined the cause of unusually intense signals obtained in immune cells by in situ hybridization histochemistry using 35S-labeled oligonucleotides. We verified that the phenomenon is an amplification of a specific signal due to a series of chemical interactions after the probe binds to a specific mRNA in the tissue. The presence of oxidative enzymes in the tissue seems to be necessary for this reaction to occur. Therefore, most cells of the immune system (e.g., macrophages, neutrophil and eosinophil leukocytes), being rich in oxidative enzymes, will show some signal amplification. The intensification of the signal can be avoided if MgCl2 is substituted for CoCl2 in the synthesis of [35S]-thiophosphate-labeled probes, if 2,3-dimercaptopropanol [British anti-Lewisite (BAL)] is added to the hybridization buffer, or if [33P]-phosphate is used instead of [35S]-thiophosphate in the labeling of the probes.

Adenosine Triphosphate↗
PubMed1994

The treatment of severe behavior problems in school settings using a technical assistance model.

We evaluated the feasibility of local school personnel conducting functional analysis and reinforcement-based treatment procedures within actual classroom settings. Following an initial in-service workshop on functional assessment and differential reinforcement procedures, on-site technical assistance was provided two to four times per month to local school personnel working in transdisciplinary teams. Overall results suggest that local school personnel were able to implement all procedures adequately with periodic technical assistance. In addition, functional analysis was effective in identifying individual maintaining contingencies, the derived treatments were effective, and the results were maintained throughout the approximate 18 months of this investigation.

Aggression↗
PubMed1994

The impact of functional analysis methodology on outpatient clinic services.

The impact of the article by Iwata, Dorsey, Slifer, Bauman, and Richman (1982) on research in severe behavior disorders has been impressive. Equally impressive, however, but not as fully recognized, has been the impact of this methodology on the routine professional activities of those who employ functional analysis methods in their daily work. As one example of this impact, we describe the evolution of assessment procedures based on "brief functional analysis" methodology in our outpatient clinics. Less apparent have been the collateral effects that occur from using these procedures. Interactions with clients and colleagues have changed in ways that result in increased positive reinforcement. In this article, we briefly discuss the positive impact functional analysis has had on one specific work behavior--outpatient clinic assessment--and describe some of the generalized effects we have experienced in related aspects of our daily professional activities.

Ambulatory Care Facilities↗
PubMed1993

Publication trends in 25 years of the Journal of Applied Behavior Analysis.

All articles published in the first 25 years of JABA (1968 to 1992) were reviewed to classify the percentage of articles published in the following categories: (a) type of article, (b) subjects, (c) setting, (d) behavior-change agent, (e) target behavior, (f) use of basic principles, and (g) miscellaneous procedures. Overall percentages and trends are reported in each category. Results indicate an increase in the percentage of articles with participants and target behaviors in developmental disabilities and a decrease in the percentage of studies targeting academic behavior, verbal behavior, and other child behavioral excesses. The most frequent setting continues to be a school; however, there is a clear trend towards community and other naturalistic settings. Results also highlight the increasing complexity and multicomponent nature of JABA interventions. Potential implications for future applications are discussed.

Journal Article↗
PubMed1992

Brief functional assessment techniques to evaluate aberrant behavior in an outpatient setting: a summary of 79 cases.

Previous investigators have analyzed the maintaining conditions for aberrant behaviors using brief functional assessment procedures. These assessment procedures have been used in one of our outpatient clinics, the Self-Injurious and Aggressive Behavior Service. This study presents a descriptive summary of the results from 79 cases during a 3-year period. The outcomes of the brief assessment were evaluated across three variables: (a) referring topography, (b) control over behavior as evaluated through brief multielement designs, and (c) the identified maintaining conditions for aberrant behavior. The limitations and future utility of brief functional assessments for identifying distinct maintaining contingencies are discussed.

Adolescent↗
PubMed1991

A brief functional analysis of aggressive and alternative behavior in an outclinic setting.

We conducted a brief functional analysis to identify maintaining variable for aggressive behavior and an alternative replacement response during a 90-min outpatient evaluation of 3 individuals with severe handicaps. During the initial analogue assessment, which focused on identifying maintaining contingencies for aggressive behavior, each participant displayed a substantially greater frequency of aggressive behavior during one condition than during any other. The contingency that produced the highest percentage of aggressive behavior was then presented for the occurrence of a specific alternative behavior (a mand). During this contingency reversal phase, each participant displayed a substantial reduction in aggressive behavior and a substantial increase in alternative behavior, thus providing a direct analysis of the equivalency of the contingency for maintaining either behavior.

Adult↗