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Biomedical subjects

N Gregg

Publications and source records attributed to N Gregg.

10 recordsLinked to original sources
PubMed1997

Assessment of human risks from exposure to low toxicity occupational dusts.

Recent animal studies have demonstrated three separate and distinct mechanisms by which low toxicity dusts can cause important chronic pulmonary effects; through overloading of clearance mechanisms, through increased toxicity associated with ultrafine particle size or by increasing the toxicity of known carcinogens in mixed exposures. The problem to be addressed is how the pathogenicity to man of various airborne dusts should be evaluated, when epidemiological evidence is often insufficient, and the reliability of extrapolation of quantitative risks from animals to man is not established. In this paper we examine the feasibility of evaluating the likely human risks of low toxicity dusts by: (1) semi-quantitative comparisons of the ability of various dusts, in animal studies, to cause overload of clearance and resulting inflammation and fibrosis; (2) postulating that these relativities apply quantitatively to human risks; and (3) estimating approximate human risks by comparisons with reference dusts for which adequate animal and human data are available. Such a decision-making framework appears feasible, provided: (1) comparable and quantitative methods are used consistently in animal studies for the measurement of impairment of clearance leading to overload and resulting inflammation and fibrosis; (2) the quantitative relationships between impairment of clearance leading to overload, and resulting inflammation and fibrosis, can be defined adequately in animals for various dusts; (3) the particle size distributions, including those in the ultrafine range, for dusts to which animals and/or humans are exposed, are taken into account (or are comparable); (4) at least two reference dusts with well-documented activities spanning the range of toxicity can be identified; and (5) the reliability of the predictions of human pathogenicity of a sample of other dusts is tested, in toxicological studies and by observation in humans. Some possible candidate reference and test dusts are identified.

Animals↗
PubMed1990

Referencing: the cohesive use of pronouns in the written narrative of college underprepared writers, nondisabled writers, and writers with learning disabilities.

The purpose of this study was to explore whether college normally achieving writers (n = 35), writers with learning disabilities (n = 35), and underprepared writers (n = 35) demonstrated any differences in their ability to utilize the semantic roles and syntactic rules needed to apply cohesive referencing in written text. Cohesive referencing (the ability to assign roles to the speaker and addressee in written communication) is a critical aspect of written language. In addition, the study explored the relation between referential cohesion and the quality and coherence of a written text.

Adult↗
PubMedDate not supplied

Coherence: the comprehension and production abilities of college writers who are normally achieving, learning disabled, and underprepared.

The ability to understand and produce coherent text structure was assessed across three groups of college writers, normally achieving, learning disabled, and underprepared. It was found that college writers with learning disabilities were more like the normally achieving writers on an assessment of comprehension of text structure. On the production of a coherent text, normally achieving writers performed better than either of the other groups, but the writers with learning disabilities (LD) performed better than the underprepared writers. These results suggest that the writers with LD demonstrate greater discrepancies between their comprehension and production of written form than either of the other groups. The writers with LD appear to understand text structure like normally achieving writers but, like the underprepared writers, they experience difficulty in the production processes.

Achievement↗
PubMedDate not supplied

The MMPI-2 profile of adults with learning disabilities in university and rehabilitation settings.

The primary purpose of this study was to compare the personality profiles of adults with learning disabilities attending a large state university (8 females, 8 males) to those participating in training programs in a rehabilitation setting (8 females, 18 males), in an attempt to identify affective variables that should be considered in transitional and postsecondary program planning. A secondary purpose of the study was to compare the performance of two groups of adults with learning disabilities (i.e., university and rehabilitation) to a normative group of college students. The mean age for all subjects was between 20 and 23 years. Findings from the study indicated that the personality profiles of individuals with learning disabilities in either a rehabilitation setting or seeking a university degree are significantly different from those of the normative population of normally achieving college students. The rehabilitation group in this study demonstrated feelings of social isolation, poor self-concept, self-doubt, and extreme restlessness. Somewhat different profiles were seen with the university group as they indicated feelings of fear, obsessive thoughts, lack of self-confidence, self-doubt, and extreme self-criticism. Both groups demonstrated profiles of individuals under extreme short- and long-term stress leading to anxiety. The study also reviewed the relevance and appropriateness of using the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) that will have direct application for the assessment and intervention of adults with learning disabilities either in a rehabilitation setting or seeking a university degree.

Adolescent↗
PubMedDate not supplied

Profiles of college students demonstrating learning disabilities with and without giftedness.

The purpose of this study was to analyze the assessment profiles of two groups of adults with learning disabilities. The first group comprised 48 adults (34 men and 14 women) demonstrating giftedness and a learning disability profile (G/LD). The second group of 46 adults (31 men and 15 women) demonstrated a learning disabled profile without giftedness (NG/LD). Both groups of participants were either attending or planning to attend college and sought testing at a university-affiliated learning disabilities center. Participants' mean age was 20 years, and all were White and from middle to upper-middle class backgrounds. Findings indicate that, as a group, the adults demonstrating a G/LD profile tended to be identified later and have more discrepancy among cognitive assessment profile scores than the NG/LD group. Cognitive subtest scores showed significant differences between the groups, but also several areas of weakness evident in both groups regardless of the presence of giftedness. These findings emphasize the importance of identifying the presence of learning disabilities among gifted populations.

Achievement↗
PubMedDate not supplied

Measuring the intelligence of college students with learning disabilities: a comparison of results obtained on the WAIS-R and the KAIT.

This study compared results obtained on the Wechsler Adult Intelligence Scale-Revised and the Kaufman Adolescent Test and Adult Intelligence; these tests were individually administered to college students with and without learning disabilities. Participants were 30 students with learning disabilities and 30 students without learning disabilities between the ages of 18 and 30. Students were administered both IQ tests and the Peabody Picture Vocabulary Test-Revised, used as a covariate measure. The results were analyzed through a repeated-measures analysis of variance. No significant differences were found between groups or between tests. A significant difference was found for both groups when Performance IQ and Fluid Scale scores were compared.

Adolescent↗