A cross-sectional household study involving 499 individuals was undertaken in an area of Minas Gerais state, Brazil, where infection with Toxoplasma gondii is endemic. Nearly 50% (n=247) of the sample had T. gondii-specific antibodies, even individuals in the 5-9-year-old age group. Approximately 12.5% (n=28) of a random subsample of participants who were positive for T. gondii antibodies had ocular lesions associated with T. gondii infection. The frequency of ocular toxoplasmosis increased significantly with age, with approximately 50% of individuals >60 years of age having lesions. The size of the ocular lesion correlated positively (r=0.85; P=.01) with the serum level of immunoglobulin A specific for tachyzoite-derived glycoinositolphospholipids. We found that sharing the same residence accounted for 30% of the variation in infectivity among residents in the sample, whereas age was the main risk factor for development of ocular toxoplasmosis in patients who were positive for T. gondii antibodies.

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-INTRODUÇÃOO β-caroteno existe naturalmente na configuração termodinamicamente mais estável e menos solúvel, a forma todo-trans. Contudo, a ocorrência natural de isô-meros cis tem sido relatada com uma certa freqüência. Teoricamente, existiriam 272 possíveis isômeros do β-caroteno, porém, apenas 12 têm sido detectados [2]. SWEENEY e MARSH [26], trabalhando com hortaliças conseguiram separar o isômero todo-trans bem como seis isômeros cis do β-caroteno, a saber: neo β-caroteno U, neo β-caroteno V, neo β-caroteno B, neo β-caroteno C, neo β-caroteno D e neo β-caroteno E. Em muitas frutas e hortaliças, os únicos isômeros do β-caroteno presentes são o todo-trans, o neo β-caroteno U (9-cis) e o neo β-caroteno B (13-cis), sendo os dois primeiros os mais comumente encontrados [5,8,9,17].

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