The CINs of Polo-Like Kinase 1 in Cancer

Simple Summary

Many alterations specific to cancer cells have been investigated as targets for targeted therapies. Chromosomal instability is a characteristic of nearly all cancers that can limit response to targeted therapies by ensuring the tumor population is not genetically homogenous. Polo-like Kinase 1 (PLK1) is often up regulated in cancers and it regulates chromosomal instability extensively. PLK1 has been the subject of much pre-clinical and clinical studies, but thus far, PLK1 inhibitors have not shown significant improvement in cancer patients. We discuss the numerous roles and interactions of PLK1 in regulating chromosomal instability, and how these may provide an avenue for identifying targets for targeted therapies. As selective inhibitors of PLK1 showed limited clinical success, we also highlight how genetic interactions of PLK1 may be exploited to tackle these challenges.

Abstract

Polo-like kinase 1 (PLK1) is overexpressed near ubiquitously across all cancer types and dysregulation of this enzyme is closely tied to increased chromosomal instability and tumor heterogeneity. PLK1 is a mitotic kinase with a critical role in maintaining chromosomal integrity through its function in processes ranging from the mitotic checkpoint, centrosome biogenesis, bipolar spindle formation, chromosome segregation, DNA replication licensing, DNA damage repair, and cytokinesis. The relation between dysregulated PLK1 and chromosomal instability (CIN) makes it an attractive target for cancer therapy. However, clinical trials with PLK1 inhibitors as cancer drugs have generally displayed poor responses or adverse side-effects. This is in part because targeting CIN regulators, including PLK1, can elevate CIN to lethal levels in normal cells, affecting normal physiology. Nevertheless, aiming at related genetic interactions, such as synthetic dosage lethal (SDL) interactions of PLK1 instead of PLK1 itself, can help to avoid the detrimental side effects associated with increased levels of CIN. Since PLK1 overexpression contributes to tumor heterogeneity, targeting SDL interactions may also provide an effective strategy to suppressing this malignant phenotype in a personalized fashion.

Targeting the CINful genome: Strategies to overcome tumor heterogeneity

Genomic instability, and more specifically chromosomal instability (CIN), arises from a number of processes that are defective in cancer, such as aberrant mitotic cell division, replication stress, defective DNA damage repair, and ineffective telomere maintenance. CIN is an emerging hallmark of cancer that contributes to tumor heterogeneity through increased rates of genetic alterations. As genetic heterogeneity within a single tumor and between tumors is a key challenge leading to treatment failures, this brings to question, whether therapeutic approaches should aim at the genetic diversity or a specific mutation present within these tumors. Answering this question will determine the future of personalized targeted therapies. Here we discuss, how the genetic diversity associated with CIN in tumor cells can be used as a therapeutic advantage and targeted by exploiting the genetic concepts of synthetic lethality and synthetic dosage lethality. Given that a number of CIN-related pathways work together to fix the DNA damage within our genome and ensure proper segregation of chromosomes, we specifically focus on the genetic interactions amongst these pathways and their potential therapeutic applicability in cancer. We also discuss, how tumor genetic heterogeneity can be targeted in emerging immunotherapeutic approaches.

Molecular characterization of an MLL1 fusion and its role in chromosomal instability

Chromosomal rearrangements involving the mixed‐lineage leukemia (MLL1) gene are common in a unique group of acute leukemias, with more than 100 fusion partners in this malignancy alone. However, do these fusions occur or have a role in solid tumors? We performed extensive network analyses of MLL1‐fusion partners in patient datasets, revealing that multiple MLL1‐fusion partners exhibited significant interactions with the androgen‐receptor signaling pathway. Further exploration of tumor sequence data from TCGA predicts the presence of MLL1 fusions with truncated SET domain in prostate tumors. To investigate the physiological relevance of MLL1 fusions in solid tumors, we engineered a truncated version of MLL1 by fusing it with one of its known fusion partners, ZC3H13, to use as a model system. Functional characterization with cell‐based assays revealed that MLL1‐ZC3H13 fusion induced chromosomal instability, affected mitotic progression, and enhanced tumorsphere formation. The MLL1‐ZC3H13 chimera consistently increased the expression of a cancer stem cell marker (CD44); in addition, we detected potential collateral lethality between DOT1L and MLL1 fusions. Our work reveals that MLL1 fusions are likely prevalent in solid tumors and exhibit a potential pro‐tumorigenic role.

Expression-based analyses indicate a central role for hypoxia in driving tumor plasticity through microenvironment remodeling and chromosomal instability

Can transcriptomic alterations drive the evolution of tumors? We asked if changes in gene expression found in all patients arise earlier in tumor development and can be relevant to tumor progression. Our analyses of non-mutated genes from the non-amplified regions of the genome of 158 triple-negative breast cancer (TNBC) cases identified 219 exclusively expression-altered (EEA) genes that may play important role in TNBC. Phylogenetic analyses of these genes predict a "punctuated burst" of multiple gene upregulation events occurring at early stages of tumor development, followed by minimal subsequent changes later in tumor progression. Remarkably, this punctuated burst of expressional changes is instigated by hypoxia-related molecular events, predominantly in two groups of genes that control chromosomal instability (CIN) and those that remodel tumor microenvironment (TME). We conclude that alterations in the transcriptome are not stochastic and that early-stage hypoxia induces CIN and TME remodeling to permit further tumor evolution.

"If I had been given that information back then": An interpretive description exploring the information needs of adults with cerebral palsy looking back on their transition to adulthood

BACKGROUND

Young people with cerebral palsy (CP) and their families have identified lack of information received during the transition to adulthood as a barrier to successful outcomes. To date, few studies have explored the information needs, preferences, timing, and method of provision from the perspective of individuals with CP.

METHOD

The methodological approach to this qualitative study was interpretive description. Nine adults living with CP, between the ages of 20 and 40, were purposively recruited in Ontario, Canada, to explore, retrospectively, their information needs during the transition to adulthood. Participants completed a 1-hour interview that explored their experiences seeking and receiving information. Interviews were transcribed verbatim, and data were analysed to create a thematic description of adults' experiences with information.

RESULTS

Three themes emerged: (a) "Recognizing and supporting information needs," which highlighted the importance of support systems to assist young people in receiving and seeking information throughout the transition; (b) "Getting creative," which highlighted strategies young people use when confronted with environmental barriers when seeking information; and (c) "Gaps and advice for the future," which highlighted the need for real-life opportunities, during the transition to adulthood, to experience some of the responsibilities of adult life.

CONCLUSION

Clinicians assisting young people with CP need purposefully to foster knowledge and skills during the transition to adulthood. They should be not only providers of information but also enablers of opportunities for immersion in real-life experiences to prepare for adult life. It is important for young people to have the opportunity to discuss challenges and exchange information with their peers.

An integrated computational and experimental study uncovers FUT9 as a metabolic driver of colorectal cancer

Metabolic alterations play an important role in cancer and yet, few metabolic cancer driver genes are known. Here we perform a combined genomic and metabolic modeling analysis searching for metabolic drivers of colorectal cancer. Our analysis predicts FUT9, which catalyzes the biosynthesis of Ley glycolipids, as a driver of advanced-stage colon cancer. Experimental testing reveals FUT9's complex dual role; while its knockdown enhances proliferation and migration in monolayers, it suppresses colon cancer cells expansion in tumorspheres and inhibits tumor development in a mouse xenograft models. These results suggest that FUT9's inhibition may attenuate tumor-initiating cells (TICs) that are known to dominate tumorspheres and early tumor growth, but promote bulk tumor cells. In agreement, we find that FUT9 silencing decreases the expression of the colorectal cancer TIC marker CD44 and the level of the OCT4 transcription factor, which is known to support cancer stemness. Beyond its current application, this work presents a novel genomic and metabolic modeling computational approach that can facilitate the systematic discovery of metabolic driver genes in other types of cancer.

Therapeutic relevance of the protein phosphatase 2A in cancer

Chromosomal Instability (CIN) is regarded as a unifying feature of heterogeneous tumor populations, driving intratumoral heterogeneity. Polo-Like Kinase 1 (PLK1), a serine-threonine kinase that is often overexpressed across multiple tumor types, is one of the key regulators of CIN and is considered as a potential therapeutic target. However, targeting PLK1 has remained a challenge due to the off-target effects caused by the inhibition of other members of the polo-like family. Here we use synthetic dosage lethality (SDL), where the overexpression of PLK1 is lethal only when another, normally non-lethal, mutation or deletion is present. Rather than directly inhibiting PLK1, we found that inhibition of PP2A causes selective lethality to PLK1-overexpressing breast, pancreatic, ovarian, glioblastoma, and prostate cancer cells. As PP2A is widely regarded as a tumor suppressor, we resorted to gene expression datasets from cancer patients to functionally dissect its therapeutic relevance. We identified two major classes of PP2A subunits that negatively correlated with each other. Interestingly, most mitotic regulators, including PLK1, exhibited SDL interactions with only one class of PP2A subunits (PPP2R1A, PPP2R2D, PPP2R3B, PPP2R5B and PPP2R5D). Validation studies and other functional cell-based assays showed that inhibition of PPP2R5D affects both levels of phospho-Rb as well as sister chromatid cohesion in PLK1-overexpressing cells. Finally, analysis of clinical data revealed that patients with high expression of mitotic regulators and low expression of Class I subunits of PP2A improved survival. Overall, these observations point to a context-dependent role of PP2A that warrants further exploration for therapeutic benefits.

Superconductivity in dense MgB2 wires

MgB2 becomes superconducting just below 40 K. Whereas porous polycrystalline samples of MgB2 can be synthesized from boron powders, in this Letter we demonstrate that dense wires of MgB2 can be prepared by exposing boron filaments to Mg vapor. The resulting wires have a diameter of 160 microm, are better than 80% dense, and manifest the full chi = -1/4pi shielding in the superconducting state. Temperature-dependent resistivity measurements indicate that MgB2 is a highly conducting metal in the normal state with rho(40 K) = 0.38 microOmega cm. By using this value, an electronic mean-free path, l approximately 600 A can be estimated, indicating that MgB2 wires are well within the clean limit. Tc, Hc2(T), and Jc data indicate that MgB2 manifests comparable or better superconducting properties in dense wire form than it manifests as a sintered pellet.

Boron isotope effect in superconducting MgB2

We report the preparation method of and boron isotope effect for MgB2, a new binary intermetallic superconductor with a remarkably high superconducting transition temperature T(c)(10B) = 40.2 K. Measurements of both temperature dependent magnetization and specific heat reveal a 1.0 K shift in T(c) between Mg11B2 and Mg10B2. Whereas such a high transition temperature might imply exotic coupling mechanisms, the boron isotope effect in MgB2 is consistent with the material being a phonon-mediated BCS superconductor.

Changes in general health and musculoskeletal outcomes in the workforce of a hospital undergoing rapid change: a longitudinal study

This article aimed to examine changes in general health and time with back pain and neck pain and to identify predictors of any such changes. Hospital workers were studied longitudinally with surveys in 1995, 1996, and 1997 (N = 712). Back and neck pain were reported only at the 2nd and 3rd surveys. There was a significant decline in general health and significant increases in time with neck pain and back pain. Predictors of changes in these outcomes were mainly work-related variables (initial or change values), such as job interference with family, job influence, work psychological demands, and hours worked.

Tri-ministry study: correlates of school-based parenting course utilization

This study examined factors associated with the utilization of universally available school-based parent training. In a randomly selected, prospectively screened, unreferred community sample of 1,498 5- to 8-year-olds, 28% to 46% of families of children with high parent-reported externalizing problems enrolled. Externalizing problems, first-child status, and a high school education were associated with increased enrollment. Single-parent status, immigrant background, and limited extracurricular child activities were associated with lower enrollment. Economic disadvantage, stress, family dysfunction, and parental depressive symptoms were not associated with participation. Most families attributed nonparticipation to busy personal schedules, inconvenient times, and logistical difficulties.

The treatment of attention-deficit hyperactivity disorder: an annotated bibliography and critical appraisal of published systematic reviews and metaanalyses

CONTEXT

The Agency for Health Care Policy and Research charged the McMaster Evidence-based Practice Center with conducting a comprehensive systematic review of the literature on the treatment of attention-deficit hyperactivity disorder (ADHD), with input from various groups of stakeholders. One strategy used to avoid duplication of work included a critical appraisal of existing systematic reviews and metaanalyses.

OBJECTIVE

To identify and appraise published metaanalyses and systematic reviews on the treatment of ADHD and to produce an annotated bibliography.

DATA SOURCES

Medline, Cumulative Index in Nursing and Allied Health (CINAHL), Healthstar, Psycinfo, and Embase were searched to September 1998; the Cochrane Database (1998 issue 3), selected Internet sites, and the files of investigators were also reviewed.

STUDY SELECTION

Review articles described as systematic reviews or metaanalyses or including a Methods section were identified independently by 3 reviewers.

DATA EXTRACTION

Two reviewers extracted, by consensus, relevant information on the name, methodological quality, ADHD-related aspects (comorbid disorders, family characteristics) of those reviews; data on the population, study setting, interventions, and outcomes evaluated by the reviews were also retrieved.

RESULTS

Thirteen reviews, published from 1982 to 1998, were included. Eight included metaanalysis and 5 a qualitative review. Nonpharmacological treatments were mentioned in 6 reviews and combination therapies in 3. One review focused on the treatment of adults. Forty-seven drugs and 20 adverse effects were mentioned. Most reviews had major methodological flaws.

CONCLUSIONS

Most published systematic reviews and metaanalyses on the treatment of ADHD have limited value for guiding clinical, policy, and research decisions. A rigorous, systematic review following established methodological criteria is warranted.

In the wake of the MTA: charting a new course for the study and treatment of children with attention-deficit hyperactivity disorder

This paper considers 3 questions addressed by the National Institute of Mental Health's Collaborative Multimodal Treatment Study of Children With Attention-Deficit Hyperactivity Disorder (ADHD), the MTA study, of pharmacological and behavioural interventions for 7- to 9-year-old ADHD children. First, do behavioural interventions represent a viable treatment option for families of children with ADHD? Second, what are the relative benefits of behavioural and pharmacological interventions? Finally, are there advantages to combining behavioural and pharmacological interventions for children with ADHD? In the absence of secondary analyses, the MTA's primary intent-to-treat analyses released to date are difficult to interpret. While behavioural interventions represented a viable option for many families, the doses achieved via systematic titration and follow-up medication-management protocols yielded larger effect sizes on unblinded primary symptom reports than did behavioural treatments or the medication management used by most families in the community control conditions. Finally, while combined medication and behavioural management demonstrates some benefits, a more definitive conclusion awaits a detailed presentation of secondary analyses and follow-up data.

Helping children adjust--a Tri-Ministry Study: I. Evaluation methodology

This report describes the evaluation methodology of the Tri-Ministry Study--a school-based trial evaluating the effectiveness of three universal programs: (a) a classwide social skills program (SS), (b) a partner reading program (RE); and, (c) a combination of both (SS & RE), to reduce and prevent behavioural maladjustment among children in the primary division (up to grade 3) of Ontario schools. The trial was done between 1991 and 1995. Sixty schools in 11 boards of education took part and were assigned randomly to program(s) during the study. Contributing to the evaluation database are detailed follow-up assessments (observations, ratings, and standard tests) on 2439 children. Three-level growth trajectory models are used to evaluate program effects. The analysis presented for illustration in this report focuses on reading achievement measured by the Wide Range Achievement Test. A companion paper presents the results of the study and discusses important methodological and programmatic issues applicable to this and other prevention studies in the field.

Detecting Attention Deficit Hyperactivity Disorder in a communications clinic: diagnostic utility of the Gordon Diagnostic System

This study examines the sensitivity, specificity, predictive values, and likelihood ratios of laboratory measures of attention and impulsivity (the Gordon Diagnostic System; GDS) in 99 school-aged boys with a history of suspected language disorders. Classification analyses comparing scores from these tests with parent and teacher ratings of attention deficit hyperactivity disorder (ADHD) symptoms revealed low positive predictive values (20.0% to 36.8%) and high negative predictive values (71.9% to 87.9%). Likelihood ratios for abnormal test scores were low to moderate (0.74 to 1.73), suggesting that these tests may not accurately identify children with ADHD. Likelihood ratios for normal scores were also low to moderate (0.41 to 1.16). These findings suggest that GDS scores have clinical utility in ruling out a diagnosis of ADHD, but not in confirming the diagnosis in a clinic population of boys with communicative disorders who are at risk for developing ADHD.

Helping children adjust--a Tri-Ministry Study: II. Program effects

This report describes program effects of the Tri-Ministry Study a school-based, longitudinal trial carried out over a 5-year period to assess the effectiveness of classwide social skills training (SS), partner reading (RE), and a combination of both (SS & RE) to reduce maladjustment among children in the primary division (up to grade 3) of Ontario schools. It also places these effects in the context of other school-based prevention studies and discusses them in view of important methodological and programmatic issues. The incremental effects attributable to the intervention programs were small and sporadic. There were statistically significant increases in prosocial behaviour observed in the playgrounds of intervention schools with no differentiation by program type. Furthermore, there was some evidence--a reduction in teacher and parent-rated externalising problems--that the combination of SS & RE and SS alone may have had modest beneficial effects. A review of nine other school-based studies, which evaluated universally delivered mental health prevention programs in general populations of students, revealed similar mixed results. There are both methodologic and programmatic issues implicated in the weak findings that have been reported to date. These issues need to be addressed to advance knowledge about the potential impact of mental-health prevention initiatives delivered universally through school-based programs. A companion paper gives the specific details on the programs, randomisation of schools, selection of subjects, measurements, and analysis.

Determinants of job stress and job satisfaction among supervisory and non-supervisory employees in a large Canadian teaching hospital

This article explores the extent to which hospital workers at a large teaching hospital at different managerial/supervisory levels (designated and non-designated supervisors, and non-supervisory staff), experienced job stress and job satisfaction prior to the re-engineering of hospital services. For all groups, increased levels of job demands were associated with higher levels of stress. Lower levels of decision latitude were associated with increased job stress for designated supervisors. Increasing levels of decision latitude were associated with both job stress and satisfaction for the other two groups. Co-worker support and teamwork contributed to increased job satisfaction for all groups.

Large group community-based parenting programs for families of preschoolers at risk for disruptive behaviour disorders: utilization, cost effectiveness, and outcome

A significant percentage of children with disruptive behavior disorders do not receive mental health assistance. Utilization is lowest among groups whose children are at greatest risk. To increase the availability, accessibility, and cost efficacy of parent training programs, this prospective randomized trial compared a large group community-based parent training program to a clinic-based individual parent training (PT) programs. All families of junior kindergartners in the Hamilton public and separate school boards were sent a checklist regarding problems at home. Those returning questionnaires above the 90th percentile were block randomly assigned to: (1) a 12-week clinic-based individual parent training (Clinic/Individual), (2) a 12-week community-based large group parent training (Community/Group), or (3) a waiting list control condition. Immigrant families, those using English as a second language, and parents of children with severe behaviour problems were significantly more likely to enroll in Community/Groups than Clinic/Individual PT. Parents in Community/Groups reported greater improvements in behaviour problems at home and better maintenance of these gains at 6-month follow-up. A cost analysis showed that, with groups of 18 families, Community/Groups are more than six times as cost effective as Clinic/Individual programs.

Coping modeling problem solving versus mastery modeling: effects on adherence, in-session process, and skill acquisition in a residential parent-training program

This trial compared two approaches used to introduce parenting skills in a residential staff training program. Fifty staff were randomly assigned to: mastery modelling in which videotaped models demonstrated new skills, coping modelling problem solving (CMPS) in which participants formulated their own solutions to the errors depicted by videotaped models, or a waiting-list control group. In both, leaders used modelling, role playing, and homework projects to promote mastery and transfer of new skills. The skills of all groups improved, but CMPS participants attended more sessions, were late to fewer sessions, completed more homework, engaged in more cooperative in-session interaction, rated the program more positively, and reported higher job accomplishment scores. These data suggest that CMPS allowing participants to formulate their own solutions may enhance adherence and reduce the resistance observed in more didactic programs.

Coping modeling problem solving versus mastery modeling: effects on adherence, in-session process, and skill acquisition in a residential parent-training program

This trial compared two approaches used to introduce parenting skills in a residential staff training program. Fifty staff were randomly assigned to: mastery modelling in which videotaped models demonstrated new skills, coping modelling problem solving (CMPS) in which participants formulated their own solutions to the errors depicted by videotaped models, or a waiting-list control group. In both, leaders used modelling, role playing, and homework projects to promote mastery and transfer of new skills. The skills of all groups improved, but CMPS participants attended more sessions, were late to fewer sessions, completed more homework, engaged in more cooperative in-session interaction, rated the program more positively, and reported higher job accomplishment scores. These data suggest that CMPS allowing participants to formulate their own solutions may enhance adherence and reduce the resistance observed in more didactic programs.

A dose-response analysis of the effects of methylphenidate on the peer interactions and simulated classroom performance of ADD children with and without conduct problems

To examine the social effects of methylphenidate, groups of 15 attention-deficit disordered boys with (ADD) and 15 ADD boys without conduct problems (ADD/CP) were paired with normal peers. ADD and ADD/CP children showed a different pattern of responses to methylphenidate. While on task behavior in ADD/CP dyads increased at 0.15 mg/kg doses, increases in ADD dyads were not observed until doses reached 0.50 mg/kg. Although controlling interaction in ADD children decreased at 0.15 mg/kg, the controlling behavior of ADD/CP children did not decline at either dose. Peers of both ADD and ADD/CP children showed reciprocal declines in controlling behavior. In both free play and cooperative task situations, 0.15 mg/kg increased social interaction in ADD boys and decreased social interaction in ADD/CP boys.

The influence of parenting stress and child behavior problems on parental estimates of expressive and receptive language development

This study examined the relative contributions of parental reports of child-related and parent-related stress to their estimates of expressive and receptive language skills on the Minnesota Child Development Inventory in 152 children referred to a communicative disorders clinic. Correlational analysis showed moderately high agreement between parental estimates and objective measures of expressive and receptive language ability. Multiple-regression analyses revealed that independent measures of language acquisition accounted for the greatest amount of variance in parental estimates of expressive and receptive language skills. Stressful child behavior accounted for a small but statistically significant proportion of the variance in estimates of expressive and receptive language skills. Parental stress, in contrast, did not contribute significantly to language estimates. These findings suggest that parents are able to formulate estimates of language development which are relatively independent of personal or child-related stressors.

Parents' attributions for achieving compliance from attention-deficit-disordered children

Ninety-one parents provided reasons for the compliance and noncompliance of either their attention-deficit-disordered, hyperactive (ADDH) or non-ADDH child in six different situations. These attributions were rated on Weiner's (1979) dimensions of locus, stability, and controllability. While parents used the same categories to explain the reasons for their children's compliance behavior, they used different dimensional ratings for these explanations. Mothers rated attributions for noncompliance as more external than did fathers. Mothers of ADDH children viewed the causes of their children's behavior to be more unstable than did mothers of control children. Also, ADDH parents had lower expectations of achieving future compliance from their child than did non-ADDH parents. Results were discussed in terms of parental experiences, the need to consider an idiosyncratic approach to attributional meaning, and treatment implications.

Dyadic peer interaction and task orientation in attention-deficit-disordered children

A sequential observational approach was used to compare peer interactions in 10 mixed dyads of ADD-H and non-Add-H boys and 10 dyads of non-ADD-H boys in laboratory cooperative and school classroom task analogue activities. Mixed dyads were found to have a greater frequency of aggression and less joint activity than control dyads in specific situations. No differences were found for measures of functional attention as measured by frequency, duration, and mean duration of task-oriented behavior. Lag sequential analyses revealed two major sequences that differentiated mixed from normal dyads. These were Verbal Reciprocity (a measure of reciprocal verbal interaction) and Retreat (a measure of social withdrawal following aggression).

Self-control and reinforcement in the management of a cerebral-palsied adolescent's drooling

Self-control of swallowing and positive reinforcement were used to eliminate drooling of a non-vocal 16-year-old with severe spastic quadriplegia. Prompts for self-controlled swallowing appeared to be more effective than positive reinforcement. The effects of treatment were maintained at three-month follow-up, but not at six months. Drooling was eliminated again by prompts for self-controlled swallowing, and had not recurred one year after treatment had ended.

Peer interactions of normal and attention-deficit-disordered boys during free-play, cooperative task, and simulated classroom situations

Groups of 30 ADD-H boys and 90 normal boys were divided into 30 mixed dyads composed of a normal and an ADD-H boy, and 30 normal dyads composed of 2 normal boys. Dyads were videotaped interacting in 15-minute free-play, 15-minute cooperative task, and 15-minute simulated classroom settings. Mixed dyads engaged in more controlling interaction than normal dyads in both free-play and simulated classroom settings. In the simulated classroom, mixed dyads completed fewer math problems and were less compliant with the commands of peers. ADD-H children spent less simulated classroom time on task and scored lower on drawing tasks than normal peers. Older dyads proved less controlling, more compliant with peer commands, more inclined to play and work independently, less active, and more likely to remain on task during the cooperative task and simulated classroom settings. Results suggest that the ADD-H child prompts a more controlling, less cooperative pattern of responses from normal peers.

Low birth weight and home intervention strategies: preterm infants

We investigated the effects of a 1-year home intervention on premature infants with low (less than 1500 g) and higher (1500-2000 g) birth weights. Infants from each weight condition were block randomly assigned to a control or to one of two treatment groups. One treatment group focused on the development of the infant; the other treatment group focused on the parent-infant interaction. The low birth weight infants obtained significantly lower Bayley mental and motor scores, and were more passive and less intense than the higher birth weight infants. However, the low birth weight infants and their parents were more responsive to the home intervention than were the higher birth weight infants, as demonstrated by changes in the Bayley mental scores and the Home Observation for Measurement of the Environment (HOME) inventory. These findings exemplify the reciprocal relationship between the child's characteristics and parental responding. The importance of selecting the most high-risk premature infants for early home intervention is outlined.

Early home intervention with low-birth-weight infants and their parents

We investigated the effects of a year-long home intervention with a sample of preterm infants randomly assigned to 1 of 3 groups: a developmental intervention, a parent-infant intervention, and a no-treatment control group. A full-term no-treatment control was also used. Both intervention approaches focused on the parent-child unit, providing training for parents to improve observational skills, emotional support, and information about community resources. However, whereas specific tasks to facilitate the child's development were provided in the developmental intervention group, the quality of the parent-infant interaction was the target for treatment in the other group. All infants were assessed at 4, 8, 12, and 16 months of age corrected for prematurity. The results suggest that although both intervention approaches were effective in modifying some aspects of the home environment and, to a lesser degree, in improving infants' cognitive development, the parent-infant interaction approach seemed to have the greater impact. These findings confirm previous observations regarding the cognitive development of preterm and full-term infants during the first 18 months of life and demonstrate changes in behavior and behavior styles in both pre- and full-term infants as they become older.

The behavioral and linguistic interactions of specifically language-delayed and normal boys with their mothers

3 studies were based on subgroups selected from larger pools of either normal children or children with delays in the expression and/or comprehension of language but normal nonverbal abilities. In Study 1, younger (28-50 months) and older (51-68 months) normal (N = 27) and language-delayed (N = 33) boys were observed interacting with their mothers in free play and structured task situations. Although language-delayed children initiated fewer interactions, their responsiveness to maternal interactions, questions, and commands did not differ from that of normal children. Mothers questioned language-delayed children less frequently during tasks but did not differ from mothers of normal children on other measures of interaction, responsiveness, control, or reward strategies. In Study 2, the complexity of maternal speech directed to normal (N = 11) and expressively delayed (N = 11) boys who were matched on the basis of comprehensive skills did not differ. Maternal speech to boys with delays in both language expression and comprehension (N = 11) was significantly less complex. In Study 3, the discrepancy between the speech complexity of mothers and that of their language-delayed children (N = 47) was greatest in younger children with greater expression and comprehension delays, who initiated fewer interactions and proved less responsive to maternal interactions and questions.

A developmental dose-response analysis of the effects of methylphenidate on the peer interactions of attention deficit disordered boys

Mixed dyads of 42 normal and 42 ADD boys were videotaped in free play, co-operative task, and simulated classrooms. ADD boys received placebo, 0.15 mg/kg, and 0.50 mg/kg of methylphenidate. ADD boys were more active and off task, watched peers less, and scored lower on mathematics and visual-motor tasks. Older boys interacted less, ignored peer interactions and play more frequently, were less controlling, and more compliant. In class, methylphenidate improved visual motor scores, and reduced the controlling behaviour, activity level, and off task behaviour of ADD boys. Normal peers displayed reciprocal reductions in controlling behaviour, activity level, and off task behaviour.

Interactions of language-delayed and normal preschool boys with their peers

This study examined the impact of specific language delay (LD) on peer interactions in preschool children. Three groups of dyads were studied: normal children interacting with normal children, normals interacting with LD children and LD children with each other. The normal children were more likely to initiate interaction when the partner was non-responsive and to attempt to dominate the interaction. The results of this study illustrate reciprocity in the social interactions of young children, the significant role of dominance and control in interaction and the sensitivity of preschool children to the characteristics of their peers.

The speech of hyperactive children and their mothers: comparison with normal children and stimulant drug effects

The language of hyperactive children has received little attention until recently. As a result, two studies of the verbal interactions of hyperactive boys with their mothers during standard 15-minute free play and 15-minute task periods are reported. In Study 1 the language of 18 hyperactive and 18 normal boys was studied while interacting with their mothers. Both the hyperactive boys and their mothers were found to use significantly more utterances in free play than normal mother-child dyads. No differences in language complexity for either mothers or children were noted between these groups in either setting. However, the ratio of the mother's level of language complexity to that of her son in free play was found to be significantly smaller in the hyperactive as compared to the normal group. Study 2 examined the effects of methylphenidate on the language of 12 of these hyperactive boys in the above situations in a drug-placebo crossover design. Drug treatment was associated with declines in the frequency but not the complexity of utterances in both hyperactive boys and their mothers in both free play and task periods.

In vivo desensitization in the management of self-injurious behavior

In vivo desensitization procedures were used successfully to manage self-injurious face slapping in a 10 yr old retarded boy. Face slapping had increased and persisted at self-injurious intensity following a surgical dental evaluation and had initially been prevented by the use of a hockey helmet. Parent's efforts to remove the helmet resulted in increased agitation, severe self-injurious behavior, and repeated efforts by the child to replace the helmet to restrain himself, or prompt adult restraint. An in vivo desensitization procedure involving increasingly extended periods without the helmet was introduced by the parents into a hierarchy of situations at home. Progress was monitored across four situations using a multiple baseline design with 6, 9, 12 and 15 month follow-up on each baseline. During treatment, self-injurious behavior was eliminated and the child developed a self-control response of wearing the helmet when agitated and spontaneously removing it when relaxed. Continued improvement was noted at 6, 9 and 12 month follow-ups. At the 15 month follow-up, no self-injurious behavior was observed and the use of the helmet was discontinued.

The interactions of normal and hyperactive children with their mothers in free play and structured tasks

Groups of 20 normal and 20 hyperactive boys ranging in age from 6 to 12 years were observed interacting with their mothers in 15-min free-play and 15-min structured-task situations. Using a 15-sec interval coding procedure, 1 observer recorded the mother's response to specific antecedent behaviors of the child while a second observer recorded the child's response to specific behaviors of the mother. Hyperactive boys proved more active, less compliant, and less likely to remain on task than nonhyperactive peers. Mothers of hyperactive boys were less likely to respond positively to the child's social interactions, solitary play activities, or compliant on-task behavior. In addition, mothers of hyperactive boys imposed more structure and control on the child's play, social interactions, and task-oriented activities. It is suggested that the controlling intrusive style observed among the mothers of hyperactive boys, while initially a response to the child's overactive, impulsive, inattentive style, may further contribute to the child's behavioral difficulties.

The effects of methylphenidate on the mother-child interactions of hyperactive children

Twenty hyperactive boys were observed while interacting with their mothers during a free play and task period on each of three occasions (no drug, drug, placebo). A triple-blind, drug-placebo crossover design was used to study the effects of methylphenidate on these interactions. A complex objective coding system was used to score the children's responses to various maternal behaviors as well as the mother's responses to a variety of children's behaviors. Results indicated that these children were more compliant with maternal commands during drug treatment. In response, mothers displayed increased attention to compliance while reducing their directiveness toward the boys. However, the hyperactive boys receiving methylphenidate initiated fewer social interactions and tended to show greater nonresponding. Thus, methylphenidate may improve the compliance of hyperactive children but tends to decrease their sociability.

Experimental analysis of EMG feedback in treating cerebral palsy

Three subjects diagnosed as having severe choreoathetoid cerebral palsy were trained in the use of EMG feedback procedures. Both between- and within-session controls, including reversals of baseline, attempted muscle control with feedback, and muscle control without feedback, were employed to analyze the contribution of feedback procedures to improvements in muscle control. The data (1) indicate that feedback enhanced muscle control and (2) provide evidence of generalization of feedback effects to no-feedback conditions and untrained muscles.

Do stimulant drugs improve the academic performance of hyperkinetic children? A review of outcome studies

Stimulant drug studies based primarily on measures of teacher opinion have frequently concluded that these drugs improve the achievement of hyperkinetic children. However, a review of those studies using more objective measures of academic performance revealed few positive short-term or long-term drug effects on these measures. What few improvements have been noted can be readily attributed to better attention during testing. The major effect of the stimulants appears to be an improvement in classroom manageability rather than academic performance. It would seem that the stimulants are not able to influence those etiologic factors, other than overactivity and inattentiveness, which predispose hyperkinetic children toward school difficulties. Hence, since the goal of pediatric intervention with these children should be to enhance school performance as well as reducing hyperactive behavior, the two should be independently and objectively monitored. Since stimulant medications fail to improve the academic performance of most of these children, additional educational assistance must be provided.