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L Atkinson

Publications and source records attributed to L Atkinson.

At least 19 recordsLinked to original sources
PubMed2000

P2X(2) receptor immunoreactivity in the dorsal vagal complex and area postrema of the rat.

Adenosine 5'-triphosphate (ATP) can function as a fast synaptic transmitter through its actions on ionotropic (P2X) and metabotropic (P2Y) receptors in neuronal tissue. The ionotropic receptors have been classified into seven subtypes (P2X(1)-P2X(7)) by molecular cloning. However, they are difficult to distinguish pharmacologically owing to an absence of specific agonists and antagonists. In this study we used neuroanatomical methods to determine the origin and neurochemical phenotype of the P2X(2) subtype of purinoceptor in the dorsal medulla of the rat. Using immunohistochemistry we observed dense networks of P2X(2) receptor immunoreactive labelled fibres and terminals in the dorsal vagal complex and area postrema, as well as labelled cell bodies in the dorsal vagal nucleus and the area postrema. The P2X(2) receptor was localized presynaptically in vagal afferent fibres and terminals in the nucleus tractus solitarius at the ultrastructural level by combining injections of an anterograde tracer (biotin dextran amine) into the nodose ganglion with pre-embedding immunogold visualization of P2X(2) immunoreactivity. Terminals immunoreactive for the P2X(2) receptor in the nucleus tractus solitarius were found to contain glutamate, but not GABA immunoreactivity by post-embedding immunogold-labelling techniques. In cell bodies in the area postrema, dual immunofluorescence also indicated that P2X(2) receptor immunoreactive cells are glutamatergic but not GABAergic. The P2X(2) receptor was localized to vagal preganglionic neurons in the dorsal vagal nucleus that were identified by prior intraperitoneal injections of the retrograde tracer FluoroGold. No cells immunoreactive for the P2X(2) receptor were observed in the nucleus tractus solitarius. The localization of P2X(2) receptor immunoreactivity presynaptically in vagal afferent terminals indicates that the receptor may be involved in modulating transmitter release from vagal afferent fibres. Furthermore, the presence of the P2X(2) receptor in vagal preganglionic cells and in glutamatergic cells of the area postrema implies that it may, respectively, play a role in regulation of vagal efferent cell activity and modulation of excitatory outputs from the area postrema to other brain regions.

Animals↗
PubMed2000

Success-based, noncoercive treatment of oppositional behavior in children from violent homes.

OBJECTIVES: Errorless compliance training is a success-based, noncoercive intervention for children with severe oppositional behavior. The strategy involves hierarchical introduction of more demanding parental requests at a gradual pace that greatly reduces noncompliance and obviates the need for constraining consequences (e.g., time-out). In this study, this approach was evaluated as a treatment for severe disciplinary problems in children from violent homes. METHOD: Participants were 15 children (aged 3-10 years) and their mothers. All participants had experienced long-term family violence. Using a multiple-baseline design, the authors trained parents in a group format and conducted observations of child compliance in the home throughout the intervention. RESULTS: Observations indicated improvements in generalized child compliance that were maintained up to 6 months posttreatment. Pre-/post maternal reports indicated significant reductions in maternal perception of child noncompliance, externalizing and internalizing problems, and parenting stress. CONCLUSIONS: Researchers have noted a dearth of empirically supported interventions for children from violent homes. Errorless compliance training may help to fill this void, as it appears well suited to treatment of difficulties encountered by these youngsters and their parents.

Adult↗
PubMed1999

Fourteen-year follow-up of children with and without speech/language impairments: speech/language stability and outcomes.

This report concerns the speech and language outcomes of young adults (N = 242) who participated in a 14-year, prospective, longitudinal study of a community sample of children with (n = 114) and without (n = 128) speech and/or language impairments. Participants were initially identified at age 5 and subsequently followed at ages 12 and 19. Direct assessments were conducted in multiple domains (communicative, cognitive, academic, behavioral, and psychiatric) at all three time periods. Major findings included (a) high rates of continued communication difficulties in those with a history of impairment; (b) considerable stability in language performance over time; (c) better long-term outcomes for those with initial speech impairments than for those with language impairments; and (d) more favorable prognoses for those with specific language impairments than for those with impairments secondary to sensory, structural, neurological, or cognitive deficits. These general conclusions held when either a liberal or a more stringent criterion for language impairment was employed. Some of these findings are consistent with those from earlier follow-up studies, which used less optimal methods. Thus, the present replication and extension of these findings with a sound methodology enables greater confidence in their use for prognostic, planning, and research purposes.

Adolescent↗
PubMed1999

Adolescent substance use disorders: findings from a 14-year follow-up of speech/language-impaired and control children.

Intervening on the development of adolescent addiction requires an understanding of the role of precursors. In a community sample of youth with and without early childhood speech/language (S/L) impairments, 12.7% of participants had a substance use disorder (SUD). Among these participants, 42.0% met criteria for more than 1 SUD. Interestingly, rates of SUDs did not differ by S/L status. However, S/L-impaired participants did show greater psychiatric comorbidity and poorer functioning. A total of 80% of S/L participants with SUDs had a concurrent diagnosis of antisocial personality disorder, compared with 43.8% of SUDs controls. In a logistic regression analysis, we found age 5 mother-rated problem behavior scores and an interaction between S/L status and teacher-rated conduct problem scores were predictive of SUDs. High conduct scores were predictive of SUDs development among control participants but not among S/L-impaired participants. First substance use and initial SUDs symptoms suggest that a window of opportunity exists to reach these troubled young people before they spiral into addiction.

Adolescent↗
PubMed1997

Serum LH concentrations in hypogonadal men during transdermal testosterone replacement through scrotal skin: further evidence that ageing enhances testosterone negative feedback. The Testoderm Study Group.

OBJECTIVE: The present study was designed to explore further the mechanism for the decline in androgen production as men age by studying the influence of ageing on testosterone negative feedback control of gonadotrophin secretion. DESIGN: Circulating testosterone, dihydrotestosterone, oestradiol, SHBG and LH concentrations were measured during long-term treatment of men with primary hypogonadism using transdermal testosterone via scrotal skin. PATIENTS: Results were compared in 12 hypogonadal men below age 40 years (34 +/- 1.1 years; mean +/- SEM), 13 middle-aged men, aged 51 +/- 2.2 years, and 10 men age 64 years or older (68 +/- 1.4 years). RESULTS: During the course of therapy, circulating LH levels were suppressed 48% (F = -2.42, P = 0.018) from 19.6 +/- 6.0 IU/I at baseline to 10 +/- 7.7 IU/I during month 15 in elderly men. By contrast, LH levels were unchanged (F = 0.31; P = 0.97) in young men (20.3 +/- 7.4 IU/I at baseline and 17.7 +/- 14.9 IU/I during treatment month 15). Intermediate results were observed in middle-aged men in whom LH levels declined slightly (F = 1.34; P = 0.24). Transdermal testosterone treatment produced similar circulating testosterone levels (F = 1.49; P = 0.24) and oestradiol levels (F = 0.60; P = 0.42) in elderly and young men. Mean plasma DHT levels were approximately 20% higher (F = 9.91; P = 0.01) during treatment in elderly men overall mean values of 8.03 +/- 0.37 nmol/l) than in young men (6.68 +/- 0.08 nmol/l). When total DHT was adjusted for higher plasma SHBG levels in elderly men, the free DHT index during treatment was similar (F = 0.23; P = 0.64) in both groups. CONCLUSIONS: These data provide further evidence that the set point for androgen negative feedback control of gonadotrophin accretion in men is altered by ageing. Taken together with previous findings, these results provide a potential explanation for the unchanged or slightly increased plasma LH levels and reduced testosterone production characteristic of elderly men. Accordingly, ageing-associated Leydig cell insufficiency leads to a decline in testosterone production, but circulating LH levels do not rise appropriately because the set-point for negative feedback is decreased.

Administration, Cutaneous↗
PubMed1997

Double-strand conformation polymorphism (DSCP) analysis of the mitochondrial control region generates highly variable markers for population studies in a social insect.

Genetic markers were obtained for the termite Nasutitermes corniger by DSCP (double-strand conformation polymorphism) analysis of PCR-amplified mitochondrial control region DNA. This procedure revealed twenty-one haplotypes in forty-four colonies, whereas a restriction fragment length polymorphism analysis detected only nine haplotypes. Sequence analysis of DSCP fragments of contrasting mobilities suggests that the electrophoretic haplotypes are caused by DNA curvature in this highly AT-rich region. DSCP markers showed that some termite colonies contained maternally unrelated queens, each of which produced worker offspring. This pattern is consistent with nest founding by unrelated queens. Due to the availability of conserved primers for the mtDNA control region, DSCP analysis may readily reveal comparatively high levels of variation in a wide variety of organisms.

Animals↗
PubMed1997

Psychological distress of parents of infants with Down syndrome.

The distress level of parents who had infants with Down syndrome (study parents) was compared to that of control parents of infants without disability (infants were all less than 2 years of age). Data were collected in two independent surveys. We matched subjects case-by-case on socioeconomic status. Analysis of pooled data indicated significantly greater depression for the study parents. However, effect sizes were small, and the prevalence of clinical depression was 5.56% (n = 108) among matched study parents and 4.26% (n = 188) among unmatched study parents. Parenting an infant with Down syndrome may cause less distress than previously thought.

Adult↗
PubMed1996

Simultaneous first-order and capacity-limited elimination kinetics after oral administration of verapamil.

In this study of the relationship between dose and plasma concentration of verapamil, controlled-release verapamil in doses of 120 mg, 180 mg, 360 mg, and 540 mg were examined. The 48 study subjects received verapamil daily during each of the 4 sequential 5-day dosing segments. Blood samples were collected frequently to obtain first-dose and steady-state (fifth dose) concentration profiles of verapamil. Plasma concentrations of R- and S-verapamil and R- and S-norverapamil were measured by stereospecific assay. Statistical comparisons of pharmacokinetic parameters and mean differences between doses were performed with analysis of variance models. At steady state, area under the concentration-time curve (AUC) values for R- and S-verapamil at both the 120-mg and 180-mg doses were about 1.5 times higher than the corresponding first-dose values. After both first and fifth doses, pharmacokinetic parameters for all four analytes were dose proportional between the 120-mg and 180-mg doses. A dose-proportional relationship also was found between the 360-mg and 540-mg dose levels. However, nonlinearity was found between the 180-mg dose and higher doses, suggesting saturable metabolic pathways. The dose-proportional relationship between the 360-mg and 540-mg doses suggests that other first-order metabolic pathways become dominant. Although results from this study are partially consistent with previously reported nonlinear verapamil kinetics, this is the first clinical study to demonstrate a dose-proportional relationship for verapamil at both low and high input rates (mg/hr). In addition, first-order disposition pathways of verapamil are probably nonexistent at medium input rates and become dominant at higher input rates.

Administration, Oral↗
PubMed1996

Court-ordered assessment: impact of maternal noncompliance in child maltreatment cases.

Parental noncompliance to court orders is associated with several factors that jeopardize safe and stable child care. We advanced three hypotheses: (1) maternal noncompliance to court-ordered assessment is associated with loss of child custody; (2) noncompliance is related to court clinic custody recommendations; and (3) noncompliance is stable across child protection and court clinic settings. Based on a sample of 56 court-referred child maltreatment cases, all hypotheses were confirmed. Results are discussed in terms of: (a) maternal noncompliance as a marker for high-risk child care; (b) our limited understanding of the phenomenal meaning of noncompliance; and (c) the dearth of empirically derived intervention methods.

Analysis of Variance↗
PubMed1996

Pain management for children and infants.

In this overview of paediatric pain management the physiological and psychological effects of untreated pain are described. Reasons for the undertreatment of pain are identified as incorrect assumptions about children and pain; personal attitudes of families, nurses and physicians; inadequate research and training; and assessment difficulties. The problems of paediatric pain assessment are considered and an assessment strategy known as QUESTT is presented. Pharmacological and nonpharmacological interventions are discussed and the conclusion reached that despite the difficulties, infant and child pain can be controlled by using adequate nursing knowledge and treatment.

Adolescent↗
PubMed1995

The effect of food, time of dosing, and body position on the pharmacokinetics and pharmacodynamics of verapamil and norverapamil.

To evaluate the influence of food, time of dosing, and body position on the steady-state pharmacokinetics of an osmotically controlled formulation of verapamil (COER-verapamil), each of 29 healthy men received one tablet a day at specified times in an open-label, multiple-dose, four-period, crossover study. The verapamil tablets were administered in a randomized, balanced, crossover design: 240 mg at 8:00 AM on an empty stomach, subjects remaining ambulatory; 240 mg at 8:00 AM on an empty stomach, subjects remaining supine for 8 hours; 240 mg at 10:00 PM with a standardized meal, subjects remaining supine for 8 hours; and 240 mg at 10:00 PM on an empty stomach, subjects remaining supine for 8 hours. Plasma verapamil concentrations were measured at steady state over the dosing interval. Steady-state plasma concentrations were achieved by the fourth administration of the drug. Neither food nor posture had any effect on the pharmacokinetics of verapamil or norverapamil, or on hemodynamic measurements. Time of dosing did affect the rate of appearance and elimination of verapamil, but had no effect on the extent of verapamil absorption, norverapamil appearance, or hemodynamic measurements.

Adult↗
PubMed1995

Child maltreatment: the collaboration of child welfare, mental health, and judicial system.

The alliance of child welfare, mental health, and legal systems has received little empirical attention, despite the magnitude of its impact on children and families. We examined the congruence of child protection agencies legal positions, court clinic recommendations, and judicial dispositions in a sample of 59 contested child maltreatment cases. Placement recommendations/decisions among all three systems were highly correlated, although the relationship was not so strong as to undermine the independence of any one system. Where there was disagreement between successive evaluations, it was in the direction of enhancing family integrity and parental access rights. We advanced three hypotheses to account for our findings: (a) changes in successive recommendations reflect the increasing sophistication of the assessment process; (b) changes reflect increasing distance from the family's ecology and are therefore increasingly ill informed; and (c) the changes are purely probabilistic, reflecting a drift toward the societal status quo.

Adult↗
PubMed1995

Age and gender related changes in stereoselective pharmacokinetics and pharmacodynamics of verapamil and norverapamil.

1. Pharmacokinetics and pharmacodynamics of R- and S-verapamil and R- and S-norverapamil were studied at steady state following administration of 180 mg verapamil delivered by a controlled-release gastrointestinal therapeutic system (COER-verapamil). 2. Of the 30 young (19 to 43 years) and 30 elderly subjects (65 to 80 years) enrolled, approximately half of each age group were women; all subjects were healthy and none were smokers. 3. Mean R- and S-verapamil and R- and S-norverapamil Cmax, Cmin, and AUC values for elderly subjects were 1.2 to 2.2 times greater than those for young subjects; these differences were statistically significant at P < 0.05. Median tmax values for young and elderly subjects were not significantly different for any enantiomer. The mean half-life values of R- and S-verapamil for elderly subjects were approximately 20 h compared with approximately 13 h for young subjects, respectively. The mean half-life values of R- and S-norverapamil for elderly subjects were approximately 31 h and 20 h, respectively, compared with approximately 19 h and 21 h for young subjects, respectively. 4. In both age groups, the mean plasma verapamil concentrations of each enantiomer were higher for women than for men at all time points. 5. Mean arterial pressure (MAP) had a significant correlation to R- (r2 = 0.86) and S-verapamil (r2 = 0.87) concentration values that was not influenced by either gender or age of the patient. Change in PR-interval also had a significant correlation to R- and S-verapamil concentration values. However, the sensitivity of the response to changes in R- and S-verapamil concentration values in elderly subjects was about 1/5 of that in younger subjects.

Adult↗
PubMed1995

Firesetting during the preschool period: assessment and intervention issues.

OBJECTIVE: To describe a methodology of assessing preschoolers involved in firesetting incidents, and outline the psychiatric implications of firesetting incidents in young children. METHOD: To outline The Arson Prevention Program for Children and present case vignettes. RESULTS: The heightened risk of burn injury or fatality in fires caused by young children is highlighted and practical suggestions for facilitating the immediate safety of the child and family are presented. CONCLUSION: Despite the popular notion that fire interest and play is relatively benign in young children, the cases show that, as with older children, firesetting in preschoolers can be associated with serious child and/or family psychopathology.

Attention Deficit Disorder with Hyperactivity↗
PubMed1994

Cervical musculoskeletal dysfunction in post-concussional headache.

Persistent headache is a common symptom following a minor head injury or concussion, possibly related to simultaneous injury of structures of the cervical spine. This study measured aspects of cervical musculoskeletal function in a group of patients (12) with post-concussional headache (PCH) and in a normal control group. The PCH group was distinguished from the control group by the presence of painful upper cervical segmental joint dysfunction, less endurance in the neck flexor muscles and a higher incidence of moderately tight neck musculature. Active range of cervical motion and postural attitude were not significantly different between groups. As upper cervical joint dysfunction is a feature of cervicogenic causes of headache, the results of this study support the inclusion of a precise physical examination of the cervical region in differential diagnosis of patients suffering persistent headache following concussion.

Adolescent↗
PubMed1994

Quality of toddler-mother attachment in children with Down syndrome: limits to interpretation of strange situation behavior.

Researchers studying social-emotional development have argued that primary attachment relationships, established by the end of the first year of life, are important organizing factors that influence the trajectory of development throughout childhood. Central to this argument is a dimension of "attachment security," along which attachments differ. For normally developing infants and toddlers, attachment security is assessed using the Ainsworth Strange Situation. However, it is not clear that this procedure is appropriate for evaluating attachment security in atypical populations. In this report, 3 samples of children with Down Syndrome (total N = 138) were assessed using the Strange Situation. The procedures were scored according to traditional protocols. Although the 3 samples differed with respect to chronological and developmental age, they showed basic similarity with respect to attachment variables. However, developmentally younger children were more difficult to classify using the standard scoring rules. Scores and classifications for the sample were compared to scores from a sample of normally developing children tested at about 12 months of age. Significant differences with respect to the distributions of cases to classification categories and with respect to the interactive scale scores suggest that the Strange Situation may be measuring different aspects of behavior for children with Down Syndrome, even when they are tested at similar developmental age levels.

Adult↗
PubMed1994

Diabetes: its differential impact on child and family.

We argue that there are two groups of diabetic children who cope differently with the treatment regimen, (a) those who maximize their metabolic control and whose difficulties are associated with better control, and (b) those who maintain control less tightly and whose difficulties are associated with poorer control. This hypothesis was investigated with a sample of 47 diabetic children and their mothers. Analyses confirmed the hypothesis, indicating two distinct groups based on the type of symptom (emotional versus conduct) the child exhibited. Symptom type was associated with mother's knowledge of diabetes, diabetic control, scores received on a standardized measure of psychological disturbance and diabetes-specific concerns. The comparison of these two diabetic groups proved more sensitive to differences in diabetic adjustment than did comparisons made on the basis of psychiatric disturbance.

Adaptation, Psychological↗