PubMed Health⌕ Search

Biomedical subjects

D J Francis

Publications and source records attributed to D J Francis.

At least 19 recordsLinked to original sources
PubMed1992

Cerebral white matter and cognition in hydrocephalic children.

Although children with hydrocephalus frequently show poor development of nonverbal cognitive skills relative to verbal skills, little is known about the neuropathologic correlates of these discrepancies. In this study, cerebral white-matter structures and lateral ventricles were measured from the magnetic resonance images of age-matched children with meningomyelocele, meningocele, and aqueductal stenosis and normal subjects. The volume of each lateral ventricle and the cross-sectional area of the corpus callosum and internal capsules were correlated with concurrent measures of verbal and nonverbal cognitive skills. The corpus callosum in the meningomyelocele and aqueductal stenosis groups was smaller. The lateral ventricles were larger, and the internal capsules were smaller, in all patient groups than in normal subjects. There were no differences in the size of the centra semiovale. Although verbal and nonverbal measures correlated positively with the size of the corpus callosum, the correlation was higher for nonverbal measures. Nonverbal measures correlated with the right, but not the left, lateral ventricle and with the area of the right and left internal capsules. Verbal measures correlated with the left, but not right, lateral ventricle and with the left, but not right, internal capsule. These results show a relationship between the corpus callosum and cognitive skills that is also influenced by hydrocephalus-related changes in the lateral ventricles and other cerebral white-matter tracts.

Adolescent↗
PubMed1992

Verbal and nonverbal skill discrepancies in hydrocephalic children.

This study evaluated a large sample (N = 90) of 5- to 7-year-old children with hydrocephalus caused by aqueductal stenosis or prematurity-intraventricular hemorrhage or associated with spina bifida. Comparison groups of normal controls, children with spina bifida and no shunt, and premature children with no hydrocephalus were also evaluated. Comparison of skill discrepancies at two occasions separated by 1 year revealed that hydrocephalic children, as a group, showed poorer nonverbal than verbal skills on measures from the McCarthy Scales of Children's Abilities, the WISC-R, and composites of neuropsychological skills. No discrepancies in verbal-nonverbal memory were found nor were any discrepancies attributable to etiology or motor demands of the tasks. Consistent with current hypotheses concerning the role of the cerebral white matter in cognitive development, these results show that hydrocephalic children in this age range generally have poorer development of nonverbal cognitive skills relative to their language development.

Child↗
PubMed1992

A five-factor model for motor, psychomotor, and visual-spatial tests used in the neuropsychological assessment of children.

Previous confirmatory factor analysis has supported a distinction between simple and complex motor skill tests in a modified and expanded Halstead Reitan test battery (HRB). The present study used a sample of 722 right-handed boys and girls, aged 9 through 12, and expanded the sample of motor, psychomotor, and visual-spatial tests to further clarify this distinction. Restricted maximum-likelihood factor analysis resulted in correlated factors of Simple Motor Skill, Complex Visual-Spatial Relations, Simple Spatial Motor Operations, Motor Steadiness, and Speeded Motor Sequencing. These results provide additional evidence for the discriminant validity of this particular battery of tests, and explicate further the skills and abilities measured in neuropsychological assessments of children referred for evaluation.

Adolescent↗
PubMed1992

The validity of discrepancy-based definitions of reading disabilities.

This study addressed the validity of distinguishing children with reading disabilities according to the presence or absence of discrepancies between intelligence test scores and academic achievement. Three definitions of reading disability were used to provide criteria for five groups of children who (a) met a discrepancy-based definition uncorrected for the correlation of IQ and achievement; (b) met a discrepancy-based definition correcting for the correlation of IQ and achievement; (c) met a low achievement definition with no IQ discrepancy; (d) met criteria a and b; and (e) met none of the criteria and had no reading disability. Comparison of these five groups on a set of 10 neuropsychological tests corrected for correlations with IQ showed that group differences were small and accounted for little of the variability among groups. These results question the validity of segregating children with reading deficiencies according to discrepancies with IQ scores.

Achievement↗
PubMed1992

Defining patterns of drinking in adolescence: a cluster analytic approach.

Most empirical approaches to defining patterns of adolescent alcohol consumption focus on frequency of drunkenness. In an attempt to define patterns of drinking in a more comprehensive way, the present study used measures of social context in addition to frequency and quantity of alcohol use. Subjects' scores on frequency, quantity and five social context variables were cluster analyzed separately for males and females. Results yielded four socially appropriate drinking patterns and three problem drinking patterns (two for males and one for females). Socially appropriate patterns for both sexes were light drinkers, light party drinkers, family drinkers and dating drinkers. Problem drinking patterns included school drinkers and solitary/stranger drinkers for males, and solitary/school drinkers for females. These groups of subjects showed significant differences on reasons for drinking and on drinking consequences even after differences due to frequency and quantity were statistically controlled. Effects of drinking primarily attributable to frequency and quantity appeared to be limited to differences concerning the physiological effects of alcohol.

Adolescent↗
PubMed1991

Neurobehavioral outcomes in diseases of childhood. Individual change models for pediatric human immunodeficiency viruses.

The growing incidence of human immunodeficiency virus-1 (HIV-1) and acquired immunodeficiency syndrome (AIDS) in children is a major public health problem. Current research emphasizes treatments for ameliorating deleterious effects on the child's neurological and behavioral development. This article outlines approaches to the assessment of individual change that may provide alternatives to more traditional approaches to the assessment of neurobehavioral outcomes in children with chronic diseases. These approaches provide more precise conceptualizations of changes that lead directly to statistical designs and measurement strategies for assessing effects of HIV-1 and AIDS on development. Such assessments can be superimposed on current clinical trial methodologies to evaluate the efficacy of pharmacological and behavioral interventions designed to improve quality of life in HIV-1 infected children.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Analysis of change: modeling individual growth.

Research on change is complicated by problems of measurement and analysis stemming from a conceptualization of change as a series of accumulating increments and decrements. In contrast, individual growth curves depict change as a continuous process underlying individual performance. These two perspectives are reviewed, and some problems with the use of difference scores in the study of change are clarified. Traditional methods are contrasted with growth curve analysis for the purposes of measuring change and studying its correlates. An illustrative example of the use of growth curves is provided from research on recovery of cognitive function following pediatric closed head injury.

Adolescent↗
PubMed1991

Methodological issues in the classification of attention-related disorders.

The classification and identification of children with attention deficit-hyperactivity disorder and related disorders involving learning and behavior are only rudimentarily developed. A major problem is the substantial overlap among children with attention, learning, and behavioral problems. The science of classification provides conceptual and methodological approaches addressing these problems. For successful classification of these children, major issues include (a) the need to provide explicit studies of identification criteria, (b) the need for systematic sampling strategies, (c) development of hypothetical classifications, and (d) systematic assessment of reliability and validity of hypothetical classifications. With the methodological advances provided by classification-oriented research, investigators and practitioners may be able to address issues involving definition and identification of children with attention and related disorders.

Attention Deficit Disorder with Hyperactivity↗
PubMed1991

Absence of synergistic effects of CNS treatments on neuropsychologic test performance among children.

Three hypotheses are proposed to account for neurobehavioral impairments following treatment with cranial radiation therapy (CRT) and intrathecal (IT) chemotherapy: CNS treatments exert a synergistic effect (A x B), an additive effect (A + B), or a single-agent effect (A or B). Eighty-five long-term survivors of non-CNS cancers aged 6 to 16 years were classified into groups on the basis of CNS treatments: CRT-IT (n = 25), CRT-No IT (n = 11), No CRT-IT (n = 24), and No CRT-No IT (n = 25). Study I findings did not provide support for synergistic mechanisms; nonorthogonal analysis of variance showed interaction effects (CRT x IT) restricted to tactile-perceptual speed. However, main effects were significant for a single agent (CRT) across a wide range of measures. General intelligence, academic achievement, verbal knowledge and reasoning, and perceptual-motor abilities were found to be significantly lower among CRT-treated groups. Study II findings provided additional support for the role of CRT; Pearson correlations within the CRT-No IT group indicated significant negative associations between CRT dose estimates for cortical regions and perceptual-motor abilities.

Adolescent↗
PubMed1989

Retardation of articular cartilage degradation by glycosaminoglycan polysulfate, pentosan polysulfate, and DH-40J in the rat air pouch model.

The rat subcutaneous air pouch model was adapted to examine the in vivo degradation of implanted rabbit articular cartilage, both with and without induced air pouch inflammation, over a 7-day period. The effects of 3 drugs, glycosaminoglycan polysulfate (Arteparon), pentosan polysulfate (SP-54), and zinc-chelated pentosan polysulfate (DH-40J), on inflammation-induced cartilage degradation were also examined. Implanted articular cartilage from noninflamed air pouches showed a reduction in total proteoglycan (PG) content (as hexuronic acid), but not in PG extractability or aggregation, compared with cartilage maintained in tissue culture. The injection of peptone into the air pouch as an inflammogen caused an influx of leukocytes and plasma exudate and a reduction in implanted articular cartilage PG content, extractability, and aggregation, which was significantly greater than that which occurred in noninflamed air pouches. In vitro experiments demonstrated that peptone did not have a direct effect on cartilage PG degradation. Daily injection of Arteparon, SP-54, or DH-40J (10 mg/kg) into peptone-inflamed air pouches significantly increased the PG content, extractability, and aggregation in implanted articular cartilage, compared with that in cartilage from non-drug-treated control animals. The infiltration of leukocytes into the peptone-inflamed air pouches was significantly reduced by daily administration of Arteparon, 10 mg/kg. At an equivalent dose, DH-40J increased leukocyte numbers in the pouch fluid, whereas SP-54 had no significant effect on leukocyte accumulation.

Animals↗
PubMed1989

Application of an enzyme-linked immunosorbent-inhibition assay to quantitate the release of KS peptides into fluids of the rat subcutaneous air-pouch model and the effects of chondroprotective drugs on the release process.

The effects of the chondroprotective agents (Arteparon, SP-54 and DH40J) on the release of proteoglycan degradation products (as keratan sulphate peptide fragments) from articular cartilage implanted into rat subcutaneous air pouches have been investigated by using an enzyme-linked immunosorbent-inhibition assay (ELISIA). The ELISIA technique was capable of quantitating the keratan sulphate peptides (KS peptides) in fluids within the range of 100-2,000 ng/ml by using the monoclonal antibody line 1/20/5-D-4 and human articular cartilage KS peptides as standard reagents. It was found that the levels of KS peptides present in the air-pouch fluid of rats treated with the chondroprotective drugs was significantly less than in fluid aspirated from the pouches of non-drug-treated control animals. On the basis of these findings we suggest that the assessment of KS peptide by ELISIAs may provide a useful means of monitoring proteoglycan breakdown products in biological fluids (e.g. synovial fluids or blood) and for evaluating the effects that antiarthritic drugs may have on this process.

Animals↗
PubMed1988

An introduction to structural equation models.

This paper provides an overview of structural equation models, and their potential for advancing neuropsychological theory and practice. Four topics are covered: (1) an overview of the various classes of models, and an introduction to the terminology and diagrams used to describe them, (2) an outline of the steps involved in applying structural equation modeling to any research problem, (3) an overview of the information used in assessing model fit, and a discussion of the role of significance tests in structural models, and (4) an outline of the advantages and disadvantages of structural equation models, and their potential contribution to neuropsychology. The paper is intended to help researchers (1) assess the relevance of these advanced statistical techniques to their own research, and (2) begin the process of successful application.

Brain Damage, Chronic↗
PubMed1988

Discriminant validity of lateral sensorimotor tests in children.

The discriminant validity of left- (LH) and right-hand (RH) sensorimotor measures from a comprehensive neuropsychological battery was tested using confirmatory factor analysis. A group of children (primarily learning disabled) was divided into analysis (n = 488) and cross-validation (n = 400) samples and the following measures were taken for both the LH and the RH Tactile Perception, Finger Agnosia, Fingertip Number Writing, Tactile Form Recognition, Finger Tapping, Grip Strength, Grooved Pegboard, and Mazes. RH- and LH scores from these tests, and scores from five WISC subtests (Information, Similarities, Vocabulary, Block Design, and Object Assembly) were analyzed in a series of four nested confirmatory factor models. Models distinguished between LH and RH skill factors, and/or between simple- and complex-skill factors. Models were compared using incremental fit ratios and chi 2 difference tests (Bentler & Bonnett, 1980). Model comparisons revealed little evidence for discriminant validity of LH and RH measures, but strong support for distinctions between measures of simple- and complex-skills. These findings were replicated in the cross-validation sample.

Adolescent↗
PubMed1988

A prospective study of neuropsychological sequelae in children with brain tumors.

Surgery and radiotherapy are the primary modalities of treatment for pediatric brain tumors. Despite the widespread use of these treatments, little is known of their acute effects (within one year posttreatment) on neuropsychological functions. An understanding of acute treatment effects may provide valuable feedback to neurosurgeons and a baseline against which delayed sequelae may be evaluated. This study compares pre- and posttherapy neuropsychological test performance of pediatric brain tumor patients categorized into two groups on the basis of treatment modalities: surgery (n = 7) and radiotherapy (n = 7). Treatment groups were composed of children aged 56 to 196 months at the time of evaluation with heterogeneous tumor diagnoses and locations. Comparisons of pretherapy findings with normative values using confidence intervals indicated that both groups performed within the average range on most measures. Outstanding deficits at baseline were observed on tests of fine-motor, psychomotor, and timed language skills, and are likely to be attributable to tumor-related effects. Comparisons of pre- versus posttherapy neuropsychological test findings indicated no significant interval changes for either group. Results suggest that surgery and radiotherapy are not associated with acute effects on neuropsychological functions.

Adolescent↗
PubMed1985

Construct validity of various memory testing procedures.

The construct validity of Wechsler Memory Scale Logical Memory, Paired Associate Learning and Visual Reproduction subtests was evaluated, as well as the validity of the Benton Visual Retention Test, and the two memory factor scales of the Luria-Nebraska Neuropsychological Battery (LNNB). The results of a series of factor analyses based on test performances of 102 subjects indicated that delayed reproduction measures of visual memory were more valid than the traditional immediate reproduction administrations, which were more closely associated with visual-perceptual-motor abilities. Construct validity was also demonstrated for Logical Memory and Paired Associate Learning. Although both LNNB measures loaded on a memory factor, item heterogeneity and brief sampling of items raised serious questions about the clinical utility of these scales.

Adult↗
PubMed1985

Ultrastructure of cystosarcoma phyllodes and fibroadenoma. A comparative study.

Electron microscopic studies were conducted on 11 cases of cystosarcoma phyllodes (6 benign, 3 malignant, 2 recurrent), 1 stromal sarcoma, and 15 cases of fibroadenomas. Particular emphasis was placed on examination of the epithelial-stromal junction. The epithelial cells were basically similar in all cases. The basal lamina of fibroadenomas tended to be reduplicated, whereas in cystosarcoma phyllodes the basal lamina was less reduplicated and even focally absent. A continuous layer of delimiting fibroblasts was not present in either type of tumor. Stromal cells were generally fibroblasts, with 2 of 15 being fibroadenomas and 2 of 11 cystosarcoma phyllodes showing myofibroblastic differentiation. The stromal sarcoma also showed smooth muscle differentiation. The authors conclude that the epithelial-stromal junction is abnormal in both fibroadenomas and cystosarcomas, but the abnormality is different in these two tumors. Increasing prominence of stromal cell junctions and of lysosomes also correlated with the diagnosis of cystosarcoma, particularly the malignant variant.

Adenofibroma↗
PubMed1977

Elastosis and other stromal reactions in benign and malignant breast tissue: an ultrastructural study.

The stroma and stromal reaction in normal breast, benign, and malignant breast tissue was studied by electron microscopy. Elastosis is the main stromal response in infiltrating duct and lobular carcinomas. Medullary carcinoma elicits no significant elastosis but intraductal carcinoma has significant local elastosis. Benign conditions such as fibroadenoma and sclerosing adenosis produced no significant elastosis. The high number of elastic fibers and the high microfibril:elastin ratio indicate that most of the elastic fibers are recently secreted, probably by fibroblasts and myofibroblasts. The factors stimulating the increased production of elastic fibers and the prognostic significance of elastosis remain unclear.

Adenofibroma↗