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Biomedical subjects

L Atkinson

Publications and source records attributed to L Atkinson.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1992

Mental retardation and WAIS-R scatter analysis.

In an earlier article, the psychometric properties of Wechsler Adult Intelligence Scale-Revised (WAIS-R) subtest difference scores were explored using a sample with IQ < 80. Data were offered which allowed the practitioner to determine whether the difference between two subtests was statistically reliable. This article represents an extension of the earlier work. It presents a set of reliability estimates for the difference between a single WAIS-R subtest and the mean of all subtests, and permits the clinician to determine whether the difference obtained by a particular examinee is statistically significant.

Adult↗
PubMed1991

Mental retardation and WAIS-R difference scores.

This article explores the psychometric properties (reliabilities, standard deviations and measurement errors) of Wechsler Adult Intelligence Scale--Revised (Wechsler, 1981) subtest difference scores. The sample consisted of 290 subjects with IQ less than 80. Results demonstrated less than satisfactory difference score reliability and disproportionate measurement error. Nevertheless, neither property was so inadequate as to render cautious profile interpretation impossible. The tabled values can help clinicians working with developmentally delayed clients interpret differences between subtest scores based on statistically reliable discrepancies.

Data Interpretation, Statistical↗
PubMed1991

Concurrent use of the Wechsler Memory Scale-Revised and the WAIS-R.

The Wechsler Memory Scale-Revised (WMS-R) is often used in combination with the Wechsler Adult Intelligence Scale-Revised (WAIS-R). The clinician must determine whether variation between Indexes and IQs is due to measurement error, or whether it reflects real discrepancies in underlying abilities. This article presents a table of statistically significant differences between WMS-R Indexes and WAIS-R IQs. Although psychometric difficulties and procedural limitations render the tabled values somewhat inaccurate, the values can nevertheless be used to augment clinical decision.

Humans↗
PubMed1991

Development and application of a multiple typing system for Clostridium difficile.

A combination of bacteriocin, bacteriophage, and plasmid typing techniques was used to differentiate strains of Clostridium difficile. A typing set of 20 bacteriocin-producing strains was established after 400 isolates of C. difficile were screened for the ability to produce bacteriocin. These strains were used to type a collection of 114 isolates of C. difficile. Forty-six (40%) of the 114 isolates were typeable, and 31 typing patterns were distinguishable. Plasmid typing of the same 114 isolates of C. difficile showed that 67 (59%) of the isolates carried up to four plasmids ranging from 7 to 60 kb in size, although most strains contained only one or two plasmids. Twenty different plasmid typing patterns were observed among the isolates. A combination of bacteriocin and plasmid typing provided 77% typeability. Fifteen (13%) of the 114 strains were typeable with five bacteriophages isolated in our laboratory, but the increase in typeability of strains over that obtainable by plasmid and bacteriocin typing was only 1.8%. Isolates that were nontypeable by bacteriocins, plasmids, or phages could be divided into two groups on the basis of positive or negative cytotoxin production. This further division of strains would increase the typeability potential by 7%; i.e., the ability to differentiate strains would rise from 77 to 84%, or perhaps 86%, if phage typing were included. We conclude that more than one of the techniques reported in this paper must be used to achieve an acceptable level of typeability of this species.

Bacterial Typing Techniques↗
PubMed1991

Use of population-specific parameters in generating WAIS-R short forms.

One method of increasing the validity of WAIS-R short forms in estimating the standard WAIS-R Full Scale IQ is by using population-specific parameters in generating WAIS-R short forms. Three studies were conducted to evaluate (1) the contribution of age-scaled scores in generating accurate short-form Full Scale IQ, (2) the psychometric properties (validity and reliability) of WAIS-R subtests with a heterogeneous psychiatric population and subsequent development of short forms based on these properties, and (3) the validity of these short forms with respect to Silverstein's (1982) and Cyr and Brooker's (1984) 2- and 4-subtest combinations. Analyses showed (1) the use of age-scaled scores did not increase validity, (2) different subtest combinations were generated based on the population-specific parameters, and (3) increases in validity occurred for some short forms derived from the clinical sample. Despite increases in validity, clinicians and researchers are cautioned about the use of short forms in clinical practice.

Adult↗
PubMed1991

The British Picture Vocabulary Scale: constructing confidence intervals to evaluate change.

The practitioner is often faced with the situation where a client has been administered a test more than once, and it must be determined whether variation in the scores obtained is either due to real change or merely reflects imprecision in measurement. This paper offers a table of standard errors of prediction, and confidence levels based thereon, which can help in making this decision where the British Picture Vocabulary Scale is used. The table is based on the normative data provided in the manual.

Adolescent↗
PubMed1990

The requirement for platelets in allergen-induced late asthmatic airway obstruction. Eosinophil infiltration and heightened airway responsiveness in allergic rabbits.

In these studies, we have used an allergic rabbit model to investigate the role of platelets in the late asthmatic response (LAR) by depleting platelets with a guinea pig antirabbit platelet antiserum (APAS). Allergen exposure of immunized rabbits pretreated with normal guinea pig serum (NGPS) to serve as a control resulted in an early- and late-phase obstructive airway response that persisted for 6 h. When the immunized animals were pretreated with APAS, the magnitude of the LAR in terms of dynamic compliance was reduced by 86.2% (p less than 0.03), but there was no difference in the early response curve. Allergen challenge of animals treated with NGPS resulted in an increased bronchial responsiveness to inhaled histamine: PD50 Cdyn geometric mean +/- SEM before, 2.36 mg/ml (3.43-1.64); after, 0.60 mg/ml (0.67-0.54) (p less than 0.01). PD50 RL before, 1.78 mg/ml (2.4-1.32); after, 0.58 mg/ml (0.81-0.47) (p less than 0.05). In contrast, when animals were treated with APAS, there was a significant inhibition of allergen-induced airway hyperresponsiveness to inhaled histamine: PD50 Cdyn geometric mean +/- SEM before, 1.42 mg/ml (2.06-0.98); after, 1.10 mg/ml (1.41-0.86) (p less than 0.4). PD50 RL before, 1.62 mg/ml (2.22-1.39); after, 1.05 mg/ml (1.35-0.82) (p greater than 0.4). Analysis of bronchoalveolar lavage fluid revealed an increase in the number of neutrophils and eosinophils after allergen exposure in control animals (p less than 0.01). However, in animals rendered thrombocytopenic, the number of eosinophils, but not neutrophils, was significantly reduced (p less than 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1990

Reliability and validity of ratio developmental quotients from the Cattell Infant Intelligence Scale.

The test-retest reliability and predictive validity of developmental quotients (DQs) derived from the Cattell Infant Intelligence Scale as administered to children with mental retardation over 30 months of age was assessed. When DQs of 36 children assessed twice with the Cattell were compared, scores were highly correlated, with no significant difference between them, indicating impressive test score stability. When DQs of 47 youngsters assessed once with the Cattell and once with the Stanford-Binet, Form L-M, were compared, scores were significantly correlated but significantly discrepant. These results were compared to previous findings (Goldstein & Sheaffer, 1988) on the Bayley Scales of Infant Development as a predictor of Stanford-Binet IQ. The DQs derived from the Bayley were superior to Cattell DQs in predicting Stanford-Binet IQ.

Child↗
PubMed1990

Intellectual and adaptive functioning: some tables for interpreting the Vineland in combination with intelligence tests.

A set of tables was provided with the differences necessary for statistical significance between the Vineland Adaptive Behavior Scales and the Bayley Scales of Infant Development. McCarthy Scales of Children's Abilities, Stanford-Binet Intelligence Scale (4th ed.), and all current Wechsler intelligence scales. This information may be beneficial in determining whether discrepancies in the Vineland and measures of intelligence can be attributed to chance alone or whether they represent real differences. In light of normative sampling diversity, regression effects, and procedural factors, which result in varying and indeterminate error in the tables, the tables can only augment clinical decision, not replace it.

Adaptation, Psychological↗
PubMed1989

Generalizability of WAIS-R factor structure within and between populations.

We investigated the reliability of the factor structure of the Wechsler Adult Intelligence Scale-Revised (WAIS-R). The WAIS-R subtests, as administered to 146 head-injured males, were factor analyzed. Two- and three-factor solutions were extracted that were consistent with past findings. Congruence coefficients were computed to determine degree of association between factor structures from all samples reported in the literature. All coefficients were impressive. Also, congruence coefficients based on factor structures derived from different samples within the same population were compared to coefficients based on different samples from different populations. No significant discrepancies emerged. Apparently, the slight factor structure variation that does exist is due to chance data fluctuation rather than to systematic population bias. This reflects well on the robustness of the WAIS-R factor structure.

Adult↗