PubMed Health⌕ Search

Biomedical subjects

A De Feo

Publications and source records attributed to A De Feo.

6 recordsLinked to original sources
PubMed2001

Video color perimetry: impairment in glaucoma suspects.

PURPOSE: To detect mild visual field impairment in asymptomatic glaucoma suspect patients. METHODS: Color perception within the visual field was tested with customized color video perimetry. The key features of the system were stimuli color desaturation, low-level luminance and equiluminant gray background. Twenty patients with asymptomatic glaucoma were tested and compared with a group of age-matched control subjects. RESULTS: Automated perimetry test findings differed significantly in the two groups, particularly for short-wavelength sensitivity (blue). The severity of color impairment correlated directly with intraocular pressure. CONCLUSION: Desaturated low-luminance video perimetry will reliably detect and quantify asymptomatic visual field defects. A previous work on multiple sclerosis has detected a mild long-wavelength (red) impairment in asymptomatic patients after an episode of optic neuritis, even in clinically unaffected fellow eyes. Our findings in glaucoma suspect patients indicate that a mild blue impairment could be the initial sign of this disease.

Adult↗
PubMed2000

A new color vep procedure discloses asymptomatic visual impairments in optic neuritis and glaucoma suspects.

OBJECTIVE: To evaluate the reliability of visual evoked potentials obtained with a set of multiple chromatic and achromatic patterns (C-VEPs) in differentiating asymptomatic perifoveal retinal impairment from central conduction impairment. METHODS: We propose a set of colored pattern stimuli that allows relatively differential activation of the magnocellular and parvocellular pathways. The system runs on a standard Pentium PC with peripherals that present stimuli and collect, analyze and print data. P1 latencies of C-VEPs obtained with achromatic (black/white) and chromatic (blue/black and red/black isocontrast) checkerboards were evaluated in normal subjects and patients with subclinical retinal impairment (glaucoma suspects) or mild neural conduction impairment (optic neuritis), none of whom had subjective visual defects. RESULTS: The procedure evoked robust cortical signals and statistically distinguished the 3 groups of subjects. The achromatic and chromatic stimuli used distinguished controls from glaucoma suspects and patients with optic neuritis. Glaucoma suspects had greater impairment of C-VEPs to blue/black checkerboards whereas patients with optic neuritis had greater impairment of responses to red/black stimuli. CONCLUSIONS: Our data suggest that chromatic patterns (color/ black, red and blue), that may activate the parvocellular and magnocellular systems differentially but not selectively, can distinguish between mild perifoveal or foveal conduction impairment. They have the additional advantage of evoking large, stable responses across all the subjects.

Adult↗
PubMed1999

Neuroimmunotoxicology: humoral assessment of neurotoxicity and autoimmune mechanisms.

The interactions between the nervous and immune systems have been recognized in the development of neurodegenerative disease. This can be exploited through detection of the immune response to autoantigens in assessing the neurotoxicity of environmental chemicals. To test this hypothesis, the following questions were addressed. a) Are autoantibodies to nervous system (NS) antigens detected in populations exposed to environmental or occupational chemicals? In sera of male workers exposed to lead or mercury, autoantibodies, primarily IgG, to neuronal cytoskeletal proteins, neurofilaments (NFs), and myelin basic protein (MBP) were prevalent. These findings were confirmed in mice and rats exposed to either metal. b) Do autoantibodies to NS antigens relate to indices of exposure? In humans exposed to either metal, and similarly in exposed rats, titers of IgG against NFs and MBP significantly correlated with blood lead or urinary mercury, the typical indices of exposure. c) Do autoantibodies correlate with sensorimotor deficits? In workers exposed to lead or mercury, a significant correlation was observed between IgG titers and subclinical deficits. Doses of metals used in rat exposures were subclinical, suggesting that autoantibodies may be predictive of neurotoxicity. d) Is the detection indicative of nervous system pathology? In rats exposed to metals, histopathology indicated central nervous system (CNS) and peripheral nervous system (PNS) damage. In addition there was evidence of astrogliosis, which is indicative of neuronal damage in the CNS, and the presence of IgG concentrated along the blood-brain barrier, as indicated by immunostaining for antibodies. e) Are immune responses to NS antigens pathogenic? Immunoglobulin fractions from rat and human sera interfered with neuromuscular function. These studies suggest that the detection of autoantibodies to NS-specific antigens may be used to monitor the development of neurotoxicity to environmental chemicals and that immune mechanisms may be involved in the progression of neurodegeneration.

Animals↗
PubMed1997

Color perimetry with personal computer.

Color visual field analysis has proven highly sensitive for early visual impairments diagnosis in M. S., yet it has never attained widespread popularity usually because the procedure is difficult to standardize, the devices are costly, and the test is fatiguing. We propose a computerized procedure running on standard PC, cost effective, clonable, and easy handled. 264 colored patches subtending 1 degree angle of vision, with selected hues and low saturation levels are sequentially and randomly displayed on gray equiluminous background of the PC screen subtending 24 degrees x 40 degrees angle of vision. The subject is requested to press a switch at the perception of the stimulus. The output provides colored maps with quantitative informations. Comparison between normals and a selected population of Patients with Multiple Sclerosis and with Glaucoma without luminance visual field defects, showed high statistical difference.

Adult↗