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Biomedical subjects

J P Harley

Publications and source records attributed to J P Harley.

At least 19 recordsLinked to original sources
PubMed1992

Applying psychometric criteria to functional assessment in medical rehabilitation: III. Construct validity and predicting level of care.

A discriminant analysis was performed using Rasch ability estimates derived from four Patient Evaluation and Conference System (PECS) subscales, to distinguish among the functional independence and impairment profiles exhibited by patients admitted into any of three levels of medical rehabilitation delineated by the National Association of Rehabilitation Facilities (NARF): (1) inpatient hospital, (2) atypical nursing home (intermediate), or (3) day program. Two discriminant functions accounted for 91% and 9% of the between-group variance, respectively. Cross-validated classification of patients into one of the three levels of care, based on discriminant function scores, produced 75% correct classification; a 66% improvement over the percentage of correct classification likely by chance alone. Results support the construct validity of the PECS subscales and indicate they may be useful in validating clinically-based admission decisions among three of the levels of care promulgated by NARF.

Activities of Daily Living↗
PubMed1992

Applying psychometric criteria to functional assessment in medical rehabilitation: II. Defining interval measures.

The use of functional assessment total scores in arithmetic operations has proliferated despite the lack of evidence supporting their use as interval measures of patient ability. Such evidence is minimally necessary to assure the validity of functional assessment total scores for clinical and management decision-making. Two requirements of interval measurement are explained and a set of Rasch analyses of 5,500 assessments using the Patient Evaluation and Conference System (PECS) are presented. The analyses were performed to determine the extent to which four item subsets identified in a previously reported factor analysis of the PECS comprise interval measures of functional independence status. Results indicate that the PECS scales meet these requirements to varying degrees. The analyses also identify areas in which measurement quality can be improved.

Activities of Daily Living↗
PubMed1991

Applying psychometric criteria to functional assessment in medical rehabilitation: I. Exploring unidimensionality.

While rehabilitation providers are facing increasing pressure to document treatment outcomes, critics have warned against the inappropriate use of ordinal functional assessment data in arithmetic operations. Two salient criticisms concern the combination of items representing multidimensional abilities into a single total score, and the indeterminate distances between hierarchical functional assessment scale categories. In this initial study, the factor structure of the Patient Evaluation and Conference System (PECS) was studied to assess the potential for unidimensional measurement. Factor analysis of a multidiagnostic dataset (n = 3,564) yielded eight factors accounting for 60% of the variance among 68 PECS items. The factors indicate that several unidimensional measures may underlie the PECS. These factors are delineated, and further studies of unidimensionality and additivity are recommended.

Activities of Daily Living↗
PubMed1985

Occupational lead neurotoxicity: improvement in behavioural effects after reduction of exposure.

To evaluate critical exposure levels and the reversibility of lead neurotoxicity a group of lead exposed foundry workers and an unexposed reference population were followed up for three years. During this period, tests designed to monitor neurobehavioural function and lead dose were administered. Evaluations of 160 workers during the first year showed dose dependent decrements in mood, visual/motor performance, memory, and verbal concept formation. Subsequently, an improvement in the hygienic conditions at the plant resulted in striking reductions in blood lead concentrations over the following two years. Attendant improvement in indices of tension (20% reduction), anger (18%), depression (26%), fatigue (27%), and confusion (13%) was observed. Performance on neurobehavioural testing generally correlated best with integrated dose estimates derived from blood lead concentrations measured periodically over the study period; zinc protoporphyrin levels were less well correlated with function. This investigation confirms the importance of compliance with workplace standards designed to lower exposures to ensure that individual blood lead concentrations remain below 50 micrograms/dl.

Behavior↗
PubMed1984

Occupational lead neurotoxicity: a behavioural and electrophysiological evaluation. Study design and year one results.

To evaluate the effects of chronic lead exposure on the nervous system in adults, a set of neurobehavioural and electrophysiological tests was administered to 99 lead exposed foundry employees and 61 unexposed workers. Current and past blood lead concentrations were used to estimate the degree of lead absorption; all previous blood lead concentrations had been less than or equal to 90 micrograms/100 ml. Characteristic signs (such as wrist extensor weakness) or symptoms (such as colic) of lead poisoning were not seen. Sensory conduction in the sural nerve was not affected. By contrast, various neurobehavioural functions deteriorated with increasing lead burden. Workers with blood lead concentrations between 40 and 60 micrograms/100 ml showed impaired performance on tests of verbal concept formation, visual/motor performance, memory, and mood. Thus impairment in central nervous system function in lead exposed adults occurred in the absence of peripheral nervous system derangement and increased in severity with increasing lead dose.

Adolescent↗
PubMed1983

Allosteric control of pyrimidine transport in Hymenolepis diminuta: an unusual kinetic isotope effect.

A thymine-uracil transport system is present in the plasma membrane brush-border of the tapeworm, Hymenolepis diminuta. The relation between initial uptake and substrate concentration of either thymine or uracil was sigmoidal when 2-14C-labelled substrates were used. In contrast, absorption kinetics of methyl-14C- and 3H-labelled substrates were hyperbolic. Since there was no metabolism of the labelled substrates during the incubation period, these differences indicate that the sigmoidal kinetics of pyrimidine transport in this organism is an isotopic effect associated with the presence of the 14C label at the 2 position in the pyrimidine ring.

Animals↗
PubMed1983

The role of occupational lead exposure in the genesis of psychiatric and behavioral disturbances.

In a prospective study of lead neurotoxicity, exposed foundry workers and referents were evaluated using a comprehensive set of neurobehavioral tests. Other performance indexes were used including a questionnaire, physical examination, and nerve conduction testing. Results show increased rates of depression, confusion, anger, fatigue and tension among workers with blood levels over 40 mcg/dl. Other aspects of neurobehavioral function, including verbal concept formation, memory, and visual/motor performance were also impaired. In view of the large number of individuals exposed to lead in their work, specific inquiries should be made of individuals with affectual complaints to clarify the nature of their work and workplace exposure to lead.

Adolescent↗
PubMed1983

Dexamethasone suppression test and depression in a rehabilitation setting.

A diagnosis of depression is frequently considered in the evaluation of patients after cerebrovascular accident (CVA); however, the usual clinical signs of depression may be either masked in depressed patients or mimicked in nondepressed patients. The dexamethasone suppression test (DST), first used to screen patients with a suspected diagnosis of Cushing's disease, has been shown in the psychiatric population to be abnormal in about 50% of patients with primary or endogenous depression. This study employed the DST to assess its diagnostic value in a population of 20 CVA patients admitted to a rehabilitation hospital. The test was found to have an 83% specificity. Results suggest that the low incidence of primary depression in this setting greatly limits the utility of the DST in such usage.

Cerebrovascular Disorders↗
PubMed1983

Monitoring neurotoxins in industry: development of a neurobehavioral test battery.

To facilitate the early detection of neurotoxicity in workers exposed to hazardous substances, we assembled a set of noninvasive neurobehavioral tests designed to assess memory, verbal concept formation, visuomotor performance, and mood. The tests were administered to an unexposed reference population and multivariate prediction equations were developed to control for effects of age, gender, and education. To define the briefest test set with appropriate sensitivity and specificity, we applied factor analysis and stepwise logistic regression to data from our referents and a group of lead-exposed workers. As a result, we have identified a comprehensive set of tests that can be administered in less than 40 minutes by trained medical technicians on plant premises and used to detect the early effects of neurotoxic substances on exposed workers. Guidelines for applying this technique to common work-place exposures, including other metals and organic solvents, are discussed.

Emotions↗
PubMed1982

Osteolysis in Trichinella spiralis infected vs noninfected rats.

1. Based upon the present inability to describe the mechanism by which calcification takes place, and the unexplored metabolism of calcium during trichinosis, studies of rat bone involvement were undertaken. 2. Significant (P less than 0.05) differences were found in experimental (Trichinella spiralis infected) rat femurs vs those of noninfected rats. 3. Analysis by atomic absorption spectroscopy, dry femur weight, and tensile stress resistance indicated an overall reduction in calcium content. 4. This calcium reduction is due to active cyst calcification. 5. Results confirming this finding revealed significant (P less than 0.05) differences at days 60-80 postinfection (the beginning of cyst calcification.

Animals↗
PubMed1982

Taurine levels in Trichinella spiralis infected versus noninfected rat diaphragms.

1. Trichinella spiralis muscle larvae caused a significant (P less than 0.05) reduction in the concentration of muscle taurine on day 10 and a highly significant (P less than 0.001) reduction on day 15 postinfection in rat diaphragms. 2. No significant (P greater than 0.05) taurine alteration was observed on days 5, 8, 30 and 60 post-infection. 3. Although taurine was found to be a constitutent of the amino acid pool of T. spiralis excysted larvae, its concentration was sufficiently low so as not to be a factor in adding to the taurine level of the host. 4. Carbon-14 labelled taurine was determined to be transported into T. spiralis excysted larvae. 5. The taurine pool in these larvae is probably derived from the host.

Animals↗
PubMed1980

Frequency of XYY males in Wisconsin state correctional institutions.

Karotyping of 3011 males at five Wisconsin state correctional institutions revealed that 1% had a chromosome abnormality. The frequency of occurrence of the XYY complement was about 5 times that for newborn males. Approximately the same rate was found among 2556 males in the three penal institutions for adults. The frequency of XYY at the institution for juvenile offenders was about ten times background. The relatively low frequency of XYY (0.38%) found at the mental-penal institution may have been due to previous sampling done there. Of the 16 XYY males discovered, only two were below the 85th percentile for height. A relatively low frequency of XYY was found among black males. Our data contradict the notion that a high rate of XYY among adult males in penal settings may be due to a disproportionately large number of tall men in prisons.

Adolescent↗
PubMed1978

Trichinella spiralis: acceleration and inhibition of cyst calcification in rats.

Daily administration of vitamin D3 (75,000 IU/kg b. wt) for 7 days accelerated Trichinella spiralis cyst calcification in rats with a 14-week-old infection. When disodium ethane-1-hydroxy-1, 1-diphosphonate (EHDP) was administered (50 mg/kg b. wt) from 2 days before until 2 days after vitamin D3 treatment, cyst calcification was inhibited. Thus, the ability to inhibit E. spiralis calcification has demonstrated for the first time.

Animals↗
PubMed1978

Hyperkinesis and food additives: testing the Feingold hypothesis.

Teacher ratings, objective classroom and laboratory observational data, attention-concentration, and other psychological measures obtained on 36 school-age, hyperactive boys under experimental and control diet conditions yielded no support for the Feingold hypothesis. Parental ratings revealed positive behavioral changes for the experimental diet; however, they seemed primarily attributable to one diet sequence. Parents' behavioral ratings on ten hyperactive, preschool boys indicated a positive response to the experimental diet; again, laboratory observations showed no diet effect.

Child↗
PubMed1978

Synthetic food colors and hyperactivity in children: a double-blind challenge experiment.

Nine hyperactive male subjects, selected on the basis of showing a favorable "response" to the Feingold diet in an earlier study, were maintained on a strict elimination (Feingold) diet for 11 weeks, and were given multiple trials of placebo and challenge food materials. Parental and teacher ratings, classroom behavior observations, and neuropsychological test scores obtained during baseline, placebo, and challenge conditions, in general, were not found to be adversely affected by the artificial color challenge materials. As expected, comparable data gathered on a matched control group showed them to receive substantially better ratings than the hyperactive subjects on the majority of the comparison measures employed. Possible explanations for the discrepancy between the dramatic clinical-anecdotal reports that have been given and the much more equivocal findings from formal experimental projects are presented.

Child Behavior Disorders↗