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F M Crinella

Publications and source records attributed to F M Crinella.

At least 19 recordsLinked to original sources
PubMed2001

Measurements of manganese with respect to calcium in histological enamel cross sections: toward a new manganese biomarker.

Airborne Mn may become an important route of exposure if the use of Mn-containing gasoline additives becomes more widespread. We report on the measurement of manganese and calcium in histological cross sections of shed deciduous tooth enamel of three human subjects. The goal of this research was to measure Mn in tooth enamel for use as a biomarker in assessing manganese exposure in cross-sectional and longitudinal studies. The histological locations can be time-specific (analogous to examining growth rings in trees). This technique, which may identify critical windows of exposure, can be important for evaluating potential vulnerability of the fetus and neonate to inhaled or ingested Mn.

Air Pollutants↗
PubMed2000

Epidemiology and control of enterobiasis in a developmental center.

OBJECTIVE: To determine if enterobiasis could be controlled in a developmental center. DESIGN: Population-based study. Annual screening of all residents by perianal swabs for enterobiasis and on admission or discharge. Treatment of infected residents and their contacts with mebendazole, 100 mg orally, with two doses given 14 days apart. MAIN OUTCOME MEASURES: The number of residents with enterobiasis and the cost of the program. RESULTS: The prevalence of enterobiasis fell rapidly and progressively, from 21% before mass medication to 1% after 3 years. CONCLUSION: Mass medication of residents with enterobiasis and their contacts was beneficial, harmless, and cost effective.

Adult↗
PubMed2000

Long-term effects of naltrexone on self-injurious behavior.

A subgroup of self-injuring patients responds positively to the opiate-blocking agent naltrexone in acute, double-blind studies. In this study we examined the effects of naltrexone after acute treatment and the long-term effects of naltrexone on SIB. Rates of SIB were collected from pretreatment baseline; a second baseline a year after the acute trial; and a subsequent 12-month double-blind, placebo-controlled treatment. A subgroup of patients decreased SIB for a year without treatment after acute exposure to naltrexone. Five participants who decreased SIB by 70% after acute treatment increased SIB to the long-term treatment with naltrexone. In contrast, those for whom SIB increased over the one-year treatment hiatus decreased their SIB after the first long-term treatment. Discussion of these complex effects considered the role of background opioid levels, dosing, and treatment regimen of naltrexone and other factors limiting receptor adaptation among patients who exhibit SIB.

Adult↗
PubMed1999

Fracture epidemiology and control in a developmental center.

During 3.5 years, 182 fractures occurred among 994 residents of a developmental center. The fracture rate was 5.2 per 100 person-years (1.7 times greater than the rate in the US population). Fracture rate was significantly greater in residents with: epilepsy, older age, male gender, white race, independent ambulation, osteoporosis, and residence in intermediate care (versus skilled nursing) units; it was not affected by severity of mental retardation. Hand and foot bones were fractured in 58% of cases. Femur fracture occurred in 13 cases (7%). Fracture was caused by a fall in 41 cases (23%); its cause was indeterminable in 105 cases (58%). Fractures, occurring without significant injury, may be an important cause of preventable disability in this population. Control measures are suggested.

Accidental Falls↗
PubMed1998

How a regression artifact makes ICFs/MR look ineffective.

Based on a simple matched-control group quasi-experiment, Conroy (1996) concluded that small ICFs for persons with mental retardation have negative quality-of-life impacts. Our analysis of Conroy's design suggests, in contrast, that the reported effect is a pure regression artifact. The flaw in Conroy's design is selecting a control group on the basis of pretest matching. Although selecting a subsample of controls by matching on static characteristics such as age or gender can reduce the confounding influence of these variables, selection on the basis of pretest scores leads invariably to a large, spurious effect. The literature on this issue dates back a century, with warnings against pretest matching by Galton, Thorndike, McNemar, Stanley, Campbell, Cronbach, and Cook. We reviewed this historical literature and then used a Monte Carlo experiment to estimate the spurious effect that Conroy would observe from pretest matching alone. The magnitude of the artifact is as large as the quality-of-life reduction that Conroy attributed to the effects of living in an ICF. We discussed the methodological logic involved in matching and the broader policy issues raised by this evaluation.

Artifacts↗
PubMed1996

Lead exposure of people with developmental disabilities: success of control measures.

In a developmental center, blood lead level was determined by atomic absorption for individuals who were admitted, discharged, or had pica. In 1977, blood lead level was 0 to 29 ug/dL in 298 (92%), 30 to 49 ug/dL in 20 (6%), and 50 to 79 ug/dL in 5 (2%) of the 323 individuals screened. In contrast, in 1994, blood lead level was 0 to 4 ug/dL in 58 (88%) and 5 to 9 ug/dL in 8 (12%) of 66 individuals screened. The observed marked decline in blood lead levels in this population has been the result of effective pica management, several local lead abatement measures, and reduced environmental lead contamination. Medical Practice Guidelines are suggested for prevention of lead poisoning in developmental centers.

Adolescent↗
PubMed1993

Food efficiency in rats following brain lesions which affect target body size: implications on the set point for target size.

Target size, i.e. body size appropriate for age, may be reset by bilateral lesions of several brain areas. The mechanism for control of target body size is unknown, but some of the loci have marked effects on gustatory behavior and/or energy metabolism. We have tested the possibility that a disturbance in energy metabolism may be a common factor in resetting target size. Food efficiency for body weight gain and for metabolic size (the 0.75 power of body weight) was determined in rats that were experimentally stunted by neonatal head-irradiation or by bilateral electrolytic lesions produced soon after weaning in the dorsomedial hypothalamic nuclei (DMH) or the substantia nigra (SN). The irradiations were carried out in males and females; the surgical lesions were produced only in males. Observations were carried out from weaning through early adulthood. Subgroups of irradiated rats and controls were fasted for 48 hours at 40 days of age. Irradiated rats had reduced food efficiency for weight gain and for metabolic size, more marked in males than in females. DMH or SN lesions did not change food efficiency for weight gain. Food efficiency for metabolic size increased after DMH lesions and declined after SN lesions. During refeeding after a fast, irradiated rats showed a normal transient increase in food efficiency for weight gain, but not for metabolic size. The differences in food efficiency following different lesions tend to exclude altered energy metabolism as a common factor in the reset of target body size.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Brain structures important for solving a sawdust-digging problem in the rat.

Young rats subjected to bilateral lesions to one of 37 different brain sites were initially trained to traverse a narrow runway to reach a goal box containing water. The test involved blocking a portion of the runway with sawdust and determining whether the animals would burrow through the sawdust to gain access to the goal box. Lesions to 30 brain sites produced deficient performance on the sawdust-digging problem. This study, combined with earlier investigation of 11 additional brain sites, shows that 41 of 48 total brain sites are involved in this task. These findings suggest that underlying brain mechanisms include a nonspecific mechanism and several specific mechanisms, such as visuospatial-attentional, visual discrimination, vestibular-proprioceptive-kinesthetic discrimination, response flexibility, but much less place learning mechanisms.

Animals↗
PubMed1990

Brain mechanisms underlying motor skill learning in the rat.

Young rats subjected to bilateral brain lesions were subsequently tested for acquisition of eight puzzle-box problems. Lesions to 12 of the 37 brain sites investigated (anterior pretectal area, subthalamus, posterolateral hypothalamus, frontocingulate cortex, anterior thalamus, mediodorsal thalamus, ventromedial thalamus, parafascicular nucleus, mamillary bodies, cerebellum, olfactory bulb, and ventromedial hypothalamus) retarded puzzle-box learning. This study, combined with earlier investigation of 11 additional brain sites, show that 21 of the 48 total brain structures are involved in motor skill learning. These findings suggest that motor skill learning requires the integrity of a nonspecific mechanism and several specific mechanisms, such as vestibular-proprioceptive-kinesthetic discrimination mechanism and probably also response flexibility, visuospatial attentional, visual discrimination and place learning mechanisms.

Animals↗
PubMed1990

Production of generalized learning deficit and permanent growth stunting by bilateral brain stem lesions.

Bilateral lesions of the globus pallidus, ventrolateral thalamus, substantia nigra, or the median raphe produce a generalized learning deficit in rats. Bilateral lesions of the dorsomedial hypothalamic nuclei stunt growth in rats without significantly disturbing endocrine functions and without producing a generalized learning deficit. Globus pallidus, ventrolateral thalamus, substantia nigra, median raphe, and dorsomedial hypothalamic nuclei lesions were produced in weanling Sprague-Dawley rats to compare their effect on physical growth. At approximately 72 d of age, all lesions had resulted in reduced body wt, tail length, and tibial length. The differences lacked significance only in body wt after median raphe lesions and tail length after ventrolateral thalamus lesions. In rats with the generalized learning deficit, body size was most stunted after substantia nigra lesions. Tibial epiphyseal width was modestly increased in rats with the generalized learning deficit. Food intake/average body wt ratio in substantia nigra and dorsomedial hypothalamic nuclei rats did not differ significantly from control values. Decreases in brain, heart, liver, kidney, and testes tended to occur after all the lesions, but brain and testis organ wt/body wt ratios were either increased or unchanged. We conclude that brain lesions producing a generalized learning deficit in rats result in impaired physical growth. The results indicated that the stunted animals maintain adequate food intake and have normal growth hormone function. The anatomical substrate for generalized learning impairment may overlap with that of a set point for body size.

Animals↗
PubMed1989

Failure to transfer a digging response to a detour problem in young rats with lesions to the "general learning system".

Recent lesion studies on young rats suggest that the components of the rodent's general learning system (GLS; a group of brain structures essential for normal acquisition of a wide range of laboratory tasks, include the regions of the caudatoputamen, globus pallidus, ventrolateral thalamus, substantia nigra, ventral tegmental area, superior colliculus, median raphe, and pontine reticular formation). The current study provides evidence that young GLS-lesioned rats, like mentally retarded humans, may be suffering from a disturbance in some superordinate ability (executive functioning) that controls the use of learning strategies in general and the transfer of learning in particular. Specifically, thirsty rats were initially trained to traverse a narrow runway to reach a goal box containing water. When a portion of the runway was blocked with sawdust, all of the sham-operated control rats succeeded in burrowing through the sawdust to gain access to the goal box, whereas most of our GLS-lesioned rats failed to do so even though they "knew how" to dig. Neocortically damaged rats showed a similar though significantly smaller deficit. Although other interpretations are possible, these data give tentative support to the view that this impairment in transfer reflects a defect in executive processing.

Animals↗
PubMed1989

Learning ability in young rats with single and double lesions to the "general learning system".

Previous lesion studies suggest that the dorsal caudatoputamen (DCP), globus pallidus, ventrolateral thalamus (VLT), substantia nigra, ventral tegmental area, superior colliculus (SC), median raphe, and pontine reticular formation are components of the general learning system (GLS) of the rat brain. The current study attempted to determine whether bilateral lesions to two components of the GLS (DCP/VLT, DCP/SC or VLT/SC) would produce greater deterioration of learning ability than bilateral lesions to only one component (DCP, VLT or SC). In all combinations examined, a second lesion added to the first led to a significantly greater learning decrement on a series of spatial reversal problems than that associated with the first lesion alone. These results are compatible with the view that the foregoing structures are elements of the same functional system concerned either directly or indirectly with general learning ability.

Animals↗
PubMed1987

Further lesion studies on the neuroanatomy of mental retardation in the white rat.

Prompted by recent findings suggesting that the basal ganglia and possibly the limbic midbrain area and brainstem reticular formation may be represented within the general learning system of the rat brain, the current study was undertaken to assess the learning ability of different groups of young rats prepared with bilateral lesions to either the caudatoputamen, nucleus accumbens, ventral pallidum, ventromedial thalamus, habenula, subthalamic nucleus, pedunculopontine tegmental nucleus, dorsal raphe, ventral tegmental area, anterior pretectal nucleus, superior colliculus, inferior colliculus, or red nucleus. The test battery included both appetitively (three distinct climbing detour problems) and aversively (visual discrimination, three cul maze, and an inclined plane discrimination) motivated learning tasks. Only those animals with lesions to the posterodorsal caudatoputamen, ventral tegmental area of Tsai, or superior colliculus were deficient in acquiring all six problems (suggestive of a generalized learning impairment) and therefore were viewed as being mentally retarded. The overall findings pertaining to the general learning system are interpreted within a conceptual framework based upon Spearman's two-factor theory of intelligence. The significance of these data for a brain-injured animal model of mental retardation is also discussed.

Animals↗
PubMed1986

The neuroanatomy of mental retardation in the white rat.

A provisional examination of a set of questions pertaining to the neuroanatomical basis of mental retardation was undertaken by assessing the learning ability of 25 different groups of young rats prepared with various cortical and subcortical lesions. The test battery included a visual discrimination, a nonvisual discrimination, a three-cul maze and three separate detour problems. Seven of the 25 groups were impaired in learning all problems (suggestive of a generalized learning impairment) and therefore were viewed as being mentally retarded. One of these groups suffered diffuse multifocal neocortical damage, while the lesions in the remaining six were located either within the parietal cortex, globus pallidus, ventrolateral thalamus, substantia nigra, median raphe or pontine reticular formation. Based upon a variety of observations, it is proposed that the generalized learning impairment seen in our brain-damaged rats, rather than being reducible to a sensory, motor, arousal-motivational-emotional, attentional, inhibitory or recent memory defect, is the product of a defect in "executive" processes.

Animals↗