|
|
|
|
|
| Barboni,M.T.S.; Gomes,B.D.; Souza,G.S.; Rodrigues,A.R.; Ventura,D.F.; Silveira,L.C.L.. |
| The purpose of the present study was to measure contrast sensitivity to equiluminant gratings using steady-state visual evoked cortical potential (ssVECP) and psychophysics. Six healthy volunteers were evaluated with ssVECPs and psychophysics. The visual stimuli were red-green or blue-yellow horizontal sinusoidal gratings, 5° × 5°, 34.3 cd/m2 mean luminance, presented at 6 Hz. Eight spatial frequencies from 0.2 to 8 cpd were used, each presented at 8 contrast levels. Contrast threshold was obtained by extrapolating second harmonic amplitude values to zero. Psychophysical contrast thresholds were measured using stimuli at 6 Hz and static presentation. Contrast sensitivity was calculated as the inverse function of the pooled cone contrast threshold. ssVECP... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Contrast sensitivity; Color vision; Steady-state visual evoked cortical potential; Visual thresholds; Spatial vision; Psychophysics. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2013000200154 |
| |
|
|
| Pinheiro,M.C.N.; Oikawa,T.; Vieira,J.L.F.; Gomes,M.S.V.; Guimarães,G.A.; Crespo-López,M.E.; Müller,R.C.S.; Amoras,W.W.; Ribeiro,D.R.G.; Rodrigues,A.R.; Côrtes,M.I.T.. |
| Four populations in the Amazon area were selected for a comparative study of mercury-exposed and non-exposed populations: São Luiz do Tapajós, Barreiras, Panacauera, and Pindobal Grande. The highest mercury levels in human hair samples were found in São Luiz do Tapajós and Barreiras, greatly exceeding the limits established by the World Health Organization. Panacauera showed an intermediate level below 9 µg/g. This was the first comparative and simultaneous evaluation of mercury exposure in the Amazon area. Also, thanks to this type of monitoring, we were able to eliminate the uncertainties about the reference dose. On the basis of these data, we can conclude that the mercury levels detected in exposed populations of the Tapajós River basin may be... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mercury; Amazon; Comparative study; Riverside populations; Human exposure; Reference dose. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2006000300012 |
| |
|
|
| Rodrigues,A.R.; Souza,C.R.B.; Braga,A.M.; Rodrigues,P.S.S.; Silveira,A.T.; Damin,E.T.B.; Côrtes,M.I.T.; Castro,A.J.O.; Mello,G.A.; Vieira,J.L.F.; Pinheiro,M.C.N.; Ventura,D.F.; Silveira,L.C.L.. |
| We measured visual performance in achromatic and chromatic spatial tasks of mercury-exposed subjects and compared the results with norms obtained from healthy individuals of similar age. Data were obtained for a group of 28 mercury-exposed subjects, comprising 20 Amazonian gold miners, 2 inhabitants of Amazonian riverside communities, and 6 laboratory technicians, who asked for medical care. Statistical norms were generated by testing healthy control subjects divided into three age groups. The performance of a substantial proportion of the mercury-exposed subjects was below the norms in all of these tasks. Eleven of 20 subjects (55%) performed below the norms in the achromatic contrast sensitivity task. The mercury-exposed subjects also had lower red-green... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mercury exposure; Mercury toxicity; Contrast sensitivity; Color vision; Visual dysfunction; Amazon riverside communities. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2007000300018 |
| |
|
| |
|
|
|
