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Biomedical subjects

R D Morris

Publications and source records attributed to R D Morris.

At least 55 records · Page 3Linked to original sources
PubMed1991

Association of waist to hip ratio and family history with the prevalence of NIDDM among 25,272 adult, white females.

The independent association of waist to hip ratio (WHR), relative weight, and family history with the prevalence of non-insulin dependent diabetes mellitus (NIDDM) was investigated in a population of 25,254 White females in the United States and Canada. A multivariate logistic analysis yielded standardized odds ratios of 1.47, 1.46, 1.54, and 1.14 for family history index, WHR, relative weight, and age, respectively.

Adult↗
PubMed1991

Physicians' management of health effects related to industrial exposures: two case reports.

Although physicians play a vital role in diagnosing and treating health effects related to industrial exposures, most physicians have limited training in occupational and environmental medicine. Two cases of industrial exposure, one affecting an individual and the other, a community, are described to illustrate the need for physicians' awareness of such exposure and their need to know how to manage potential health effects. Resources to assist in identifying and managing these exposures and their related conditions are discussed.

Accidents, Occupational↗
PubMed1990

Semantic discrimination in nonspeaking youngsters with moderate or severe retardation: electrophysiological correlates.

Recent studies have used auditory evoked response (AER) procedures to study word meaning in young infants. The present study represents an initial application of these procedures to nonspeaking subjects with moderate or severe mental retardation. AERs were recorded from electrodes placed on the scalp over frontal, temporal, and parietal regions of the left and right hemispheres. As six symbol-experienced subjects viewed visual-graphic symbols (lexigrams), a series of probe tones were presented to elicit the AERs. Half of the symbols were meaningful to the subjects. AER activity recorded from the left hemisphere frontal and temporal electrode sites discriminated between the meaningful and meaningless symbols. Discriminant function analyses indicated that the wave-forms could be correctly classified in terms of the evoking stimulus with greater than 80% accuracy. These findings support the usefulness of AERs for studying the neurolinguistic processes underlying behavioral measures of language performance of difficult-to-assess populations.

Adolescent↗
PubMed1990

Cardiovascular regulation during head-out water immersion exercise.

Head-out water immersion is known to increase cardiac filling pressure and volume in humans at rest. The purpose of the present study was to assess whether these alterations persist during dynamic exercise. Ten men performed upright cycling exercise on land and in water to the suprasternal notch at work loads corresponding to 40, 60, 80, and 100% maximal O2 consumption (VO2max). A Swan-Ganz catheter was used to measure right atrial pressure (PAP), pulmonary arterial pressure (PAP), and cardiac index (CI). Left ventricular end-diastolic (LVED) and end-systolic (LVES) volume indexes were assessed with echocardiography. VO2max did not differ between land and water. RAP, PAP, CI, stroke index, and LVED and LVES volume indexes were significantly greater (P less than 0.05) during exercise in water than on land. Stroke index did not change significantly from rest to exercise in water but increased (P less than 0.05) on land. Arterial systolic blood pressure did not differ between land and water at rest or during exercise. Heart rates were significantly lower (P less than 0.05) in water only during the two highest work intensities. The results indicate that indexes of cardiac preload are greater during exercise in water than on land.

Adult↗
PubMed1989

Laterality for visual-spatial processing in two language-trained chimpanzees (Pan troglodytes).

Most reviews of laterality in nonhuman primates indicate that hemispheric asymmetries, similar to those found in humans, are not evident. With the growing evidence for cognitive processes germane to language in apes, in addition to their phylogenetic similarity to humans, they appear to be useful candidates for studies of laterality. Laterality for visual-spatial processing in two language-trained chimpanzees (Pan troglodytes) was investigated with a visual half-field paradigm. Initially, the chimpanzees were taught to manipulate a joystick that controlled the movement of a cursor on a computer monitor to a central fixation point. Subjects were then taught a visual discrimination based on the location of a short line contained within a geometric form. Testing consisted of systematic presentation rates of 15, 122, and 226 ms to the left and right visual fields. For half of the trials, subjects used their left hand to respond and, alternately, used the right hand for the remaining trials. Accuracy and reaction time were the dependent measures. One subject demonstrated significantly faster reaction times to stimuli presented to the left visual field (LVF) regardless of which hand was used to respond. The other subject demonstrated a significant LVF bias when using the left hand to respond. The results are discussed in the context of current theories on the evolution of laterality and its relation to linguistic functioning.

Animals↗
PubMed1989

Obesity and heredity in the etiology of non-insulin-dependent diabetes mellitus in 32,662 adult white women.

Obesity and family history of non-insulin-dependent diabetes mellitus were examined in a cross-sectional study of 32,662 white women in the United States and Canada who were members of the TOPS (Take Off Pounds Sensibly) Club, Inc., with respect to the association between these two factors and the prevalence of diabetes by using questionnaire data originally collected in 1969. A family history index based upon the reported presence of diabetes among siblings, parents, and grandparents was used to grade hereditary factors on a scale of zero to five. The ratio of actual to ideal weight was used to categorize levels of obesity. The prevalence of diabetes increased consistently with increasing levels of either obesity or family history. The two factors appear to present independent risks for diabetes. Among women with no family history of diabetes, the odds ratio for diabetes associated with a weight 75 per cent or more above ideal in comparison with a weight less than 10 per cent above ideal was 7.2. Among women who were less than 10 per cent above ideal weight for their height, a comparison between women with a family history index of 1.5 or greater and women with no family history of the disease showed an odds ratio for diabetes of 6.0. Women with both risk factors (family history index of 1.5 or greater and relative weight of 1.75 or greater) had an overall odds ratio for diabetes of 22.8 when compared with women who had no family history of diabetes and a weight less than 10 per cent above ideal. Further analysis showed the combination of these factors to have a positive synergistic effect. The interaction follows a multiplicative pattern.

Adult↗
PubMed1988

Classification in neuropsychology: a theoretical framework and research paradigm.

Classification research is not well understood in neuropsychology. A major purpose of classification research is to establish and investigate inclusion and exclusion criteria for group formation. Therefore, classification represents the foundations of clinical assessment as well as traditional contrasting groups research designs in neuropsychology. Null results in neuropsychological research do not pinpoint the basis for the absence of group differences. The most frequent research focuses on the original theory or the validity of the dependent variables. Classification research focuses on a third potential problem area, which has received little attention: poor subject classifications (invalid independent variables). The purpose of this paper is to describe a general theoretical framework and outline a set of decisions for conducting classification research in neuropsychology.

Brain Damage, Chronic↗
PubMed1987

Effect of head-out water immersion on cardiorespiratory response to dynamic exercise.

Head-out water immersion is known to produce several cardiopulmonary adjustments at rest due to a cephalad shift in blood volume. The purpose of this study was to determine the effect of head-out water immersion on the cardiorespiratory response to graded dynamic exercise. Nineteen healthy middle-aged men performed upright cycling exercise at 40, 60 and 80% of maximal oxygen consumption on land and in water (31.0 +/- 1.0 degrees C) to the shoulders. Cardiac output (measured by the carbon dioxide rebreathing technique) was significantly greater in water at 40 and 80% maximal oxygen consumption. Stroke volume was significantly elevated at all stages of exercise. Heart rate did not differ significantly at 40 and 60% maximal oxygen consumption but was significantly lower in water at 80% maximal oxygen consumption. Total ventilation did not differ significantly in water and on land at any stage of exercise. The results suggest that the central redistribution of blood volume with head-out water immersion leads to an increase in stroke volume. Because there is not a proportional decrease in heart rate with the elevated stroke volume, cardiac output is regulated at a higher level during upright exercise in water compared with that on land. In conclusion, there are serious limitations of available, prerecorded rhythm data bases for designing and testing of automatic external defibrillators. Performance can be adequately assessed only by extensive clinical tests, which seem mandatory for this new and important type of defibrillator.

Adult↗
PubMedDate not supplied

Localization of disease clusters using regional measures of spatial autocorrelation.

Maps of disease rates are often used to identify regions with elevated disease rates. The goal of this study was to develop and evaluate a regional measure of spatial autocorrelation for localization of these clusters. A regional spatial autocorrelation coefficient (RSAC) was defined and a theoretical mean and standard deviation was derived for its probability distribution. The RSAC was used to identify spatial units that belong to disease clusters. The sensitivity and specificity of the RSAC method in detecting simulated disease clusters was evaluated. For comparison the simulated data were also used to evaluate methods employed by the National Cancer Institute (NCI) for mapping cancer mortality in the United States. The distribution of pancreatic cancer among the elderly white male population in the United States was also evaluated. Within a simulated disease cluster with a relative risk of 2, the RSAC method detected between 75 per cent and 91 per cent of the units depending on the size of the spatial unit used for the analysis. The corresponding sensitivities of the NCI method ranged from 9 per cent to 68 per cent. The RSAC map of pancreatic cancer demonstrated an area of positive clustering (clustering of high rates) in the south central United States. The RSAC method localized disease clusters with greater sensitivity than the NCI method, particularly when geographic units were small. The RSAC method is an effective tool for the identification of regional disease clusters.

Aged↗
PubMedDate not supplied

NES test performance in a large US Army veteran sample: relationships with both demographic factors and traditional neuropsychological measures.

A large sample of Vietnam-era US Army veterans completed a set of 16 neuropsychological tests, including six computer-based tests from the Neurobehavioral Evaluation System (NES), during medical examinations supervised by the US Centers for Disease Control (CDC). Data for 881 participants of the Agent Orange Validation Study (AOV) and Vietnam Experience Study (VES) were available for analysis from public access data tapes provided by CDC. Information was available for several potential covariates from demographic questionnaires, a medical examination, and a medical history. Explorator, principal components factor analysis of 16 test variables yielded four factors, including one on which most of the NES tests loaded. The single best predictor of most neuropsychological performance variables was an index of general intellectual level as measured at entry into the Army almost 20 years before the neuropsychological examinations. Alcohol drinking variables were not related to neuropsychological performance. Several measures of general intelligence were compared for use as covariates of neuropsychological test performance. All were superior to years of education in statistically controlling for general intellectual level.

Adult↗
PubMedDate not supplied

Use of passive surveillance data to study temporal and spatial variation in the incidence of giardiasis and cryptosporidiosis.

OBJECTIVE: The goal of this study was to evaluate temporal and spatial variations in the reporting of cases of giardiasis and cryptosporidiosis to a passive surveillance system, and to assess the relationship of those variations to source of drinking water, adjusting for socioeconomic variables. METHODS: The authors analyzed temporal and spatial patterns for 4,058 cases of giardiasis and 230 cases of cryptosporidiosis reported to the Massachusetts Department of Public Health for 1993-1996. They linked each reported case to a database containing information on source of residential water supply and socioeconomic characteristics and evaluated the association between these factors and reporting rates using regression techniques. RESULTS: Reports of giardiasis and cryptosporidiosis were highest for the mixed unfiltered drinking water supply category. Reports of giardiasis were associated with income levels. Increases in reporting for both giardiasis and cryptosporidiosis were seen in summer to early fall. During a suspected outbreak of cryptosporidiosis n the city of Worcester in 1995, a significant increase in reported cases was also observed in the Boston metropolitan area. Following the suspected outbreak, weekly giardiasis rates increased slightly in Worcester and the Boston metropolitan area, while reporting of cryptosporidiosis increased dramatically. CONCLUSIONS: Consistently collected passive surveillance data have the potential to provide valuable information on the temporal variation of disease incidence as well as geographic factors. However, passive surveillance data, particularly in the initial period of surveillance, may be highly sensitive to patterns of diagnosis and reporting and should be interpreted with caution.

Adolescent↗
PubMedDate not supplied

Relation between Kaufman Brief Intelligence Test and WISC-III scores of children with RD.

Concurrent validity of the Kaufman Brief Intelligence Test (K-BIT) with the Wechsler Intelligence Scale for Children-Third Edition (WISC-III) was evaluated, as well as the K-BIT's accuracy as a predictor of WISC-III scores, in a sample of young children with reading disabilities. The two measures were administered to 65 children from Atlanta, Boston, and Toronto who ranged from 6-5 to 7-11 years of age at testing. Correlations between the verbal, nonverbal, and composite scales of the K-BIT and WISC-III were .60, .48, and .63, respectively. Mean K-BIT scores ranged from 1.2 to 5.0 points higher than the corresponding WISC-III scores. Standard errors of estimation ranged from 10.0 to 12.3 points. In individual cases, K-BIT scores can underestimate or overestimate WISC-III scores by as much as 25 points. Results suggest caution against using the K-BIT exclusively for placement and diagnostic purposes with young children with reading disabilities if IQ scores are required.

Child↗