Abstracts » Food/cooking/nutrition

Beta-carotene increases lung cancer incidence in cigarette smokers

Article Abstract:

Beta carotene seems to increase the rate of lung cancer in smokers, an unexpected relationship not based on animal models. More cigarette smokers who took beta carotene supplements had lung cancer than those taking no supplements. Since beta carotene may be carcinogenic in smokers, animal studies about the metabolic effects of this vitamin should be conducted first. As a precursor of vitamin A, beta carotene may alter regulatory mechanisms in the body that cause cancer.

Health aspects, Models, Smoking, Lung cancer, Cocarcinogens, Carcinogens, Beta carotene

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Retinoic acid response elements as positive and negative regulators of the expression of the Homeobox b-1 gene

Article Abstract:

Retinoic acid response elements (RARE) in the brain may act as positive or negative regulators during embryonal growth. Early positive gene expression in the Hoxb-1 gene as well as late negative gene expression may promote normal fetal development or a disruption of normal growth, respectively. Details of this molecular activity may explain the mechanics of teratogenesis associated with excess retinoic acid.

Research, Genetic aspects, Homeobox genes, Tretinoin, Embryology, Human, Human embryology, Teratogenesis

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A new metabolite of retinol: all-trans-4-oxo-retinol as a receptor activator and differentiation agent

Article Abstract:

A newly described metabolite of retinol may explain some of the activity of vitamin A. The metabolite, all-trans-4-oxoretinol, is not carboxylated and yet it still binds to the retinoic acid receptor (RAR). It induces differentiation of an embryonal carcinoma F9 cell line as well as transcription of the homeobox Hoxa-1 gene. It stimulates laminin B1 synthesis and induces teratogenesis in Xenopus laevis.

Causes of, Cell differentiation, Retinoids

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