Beta-carotene (ß-carotene) is one of many carotenoids found in nature. In the human nutrition field, evidence suggests that higher blood levels of ß-carotene as well as other carotenoids such as alpha-carotene, lycopene, lutein, zeaxanthin, and ß-cryptoxanthin may be associated with lower risk of several chronic diseases. ß-carotene, a-carotene, and ß-cryptoxanthin have pro-vitamin A activity, ...

Absorption and storage of [14C]beta-carotene in control and beta-carotene-fed (BC-fed) rats were determined. Pre-feeding with beta-carotene for 2 weeks caused a 1.9-fold stimulation of its own absorption as well as its conversion to retinyl esters, whereas the absorption of [3H]retinyl acetate was unaffected. The liver and the lungs accounted for 60% and 30%, respectively, of the total recovere...

Does beta-carotene increase, rather than decrease, human lung cancer rates? A large body of observational epidemiologic study has demonstrated that individuals who eat more fruits and vegetables rich in carotenoids and/or who have higher levels of serum betacarotene have a lower risk of cancer, particularly lung cancer. This inverse relationship has been particularly strong in lung cancer patie...

exposure buildup factors have been calculated by monte carlo method for point isotropic gamma ray sources, penetrating a two-layer spherical shield of water surrounded by lead, and the effect of bremsstrahlung radiation on buildup factors has, in particular, been investigated, the results of which are in good agreement with previous works. the buildup factors were then calculated for various co...

A new HPLC/DAD (Diode Array Detector) method is proposed for the identification of some carotene isomers. The operating conditions adopted permit the resolution of α-carotene, all-trans-β-carotene, 9-cis-β-carotene, 13-cis-β-carotene and 15-cis-β-carotene. Moreover, the chromatographic conditions reported are simplified in respect of those reported up to now. The method is applied to the determ...

Patients undergoing carotid endarterectomy were pretreated with low-dose, oral beta carotene to determine whether the carotenoid content of plaque could be increased in vivo. Beta carotene-treated patients had a 50-fold increase in their plaque beta carotene level from 0.066 to 3.3 micrograms beta carotene/g plaque. Microscopy and microspectrophotometry demonstrated that plaque from beta carote...

BACKGROUND Intervention studies have shown an increased mortality in patients who received beta-carotene. However, the mechanisms involved in this phenomenon are still unknown. OBJECTIVE Evaluate the influence of beta-carotene on oxidative stress and the expression of connexin 43 in rat hearts. METHODS Wistar rats, weighing approximately 100 g, were allocated in two groups: CONTROL GROUP (n...

Metallic eye shields have been widely used for near-eye treatments to protect critical regions, but have never been incorporated into treatment plans because of the unwanted appearance of the metal artifacts on CT images. The purpose of this work was to test the use of an acrylic dummy eye shield as a substitute for a metallic eye shield during CT scans. An acrylic dummy shield of the same size...

2-Oxo-carotenoids, 2-Hydroxy-carotenoids, [uC]/?-Carotene, Metabolism, Stick Insects The carotenoids of the stick insect, Ectatosoma tiaratum, were studied by spectroscopic and chemical methods. The /?,/?-type pigments are /?,/?-carotene, /?,/?-caroten-2-one, /?,/?-caroten-2-ol, /?,/?-carotene-2,2'-dione, 2'-hydroxy-/?,/?-caroten-2-one, ß,^-carotene-2,2'-diol, 3,4-didehydro-/?,/?carotene-2,2'-d...

The three beta-carotene intervention trials: the Beta Carotene and Retinol Efficacy Trial (CARET), Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC), and Physician's Health Study (PHS) have all pointed to a lack of effect of synthetic beta-carotene in decreasing cardiovascular disease or cancer risk in well-nourished populations. The potential contribution of beta-carotene suppleme...