How retinoids regulate breast cancer cell proliferation and apoptosis.

Breast cancer still remains a major problem in its incidence, morbidity and mortality; therefore, more effective strategies for its prevention are urgently needed. Retinoids, natural and synthetic derivatives of vitamin A, possess antiproliferative and proapoptotic properties, making them a promising class of chemopreventive agents against breast cancer. The efficacy of all-trans retinoic acid, 9-cis-retinoic acid, LGD1069 (Targretin, bexarotene), and N-(4-hydroxyphenyl)retinamide (fenretinide) as breast cancer chemopreventive agents is being studied. A better understanding of the molecular mechanisms of action of these agents should lead to improvements in their clinical application. In this review, we discuss the mechanisms by which retinoids exert their antiproliferative and apoptotic effects in breast cancer cells.

Detection of plum pox virus in apricot seeds.

Twelve different apricot selection trees from a germplasm collection naturally infected with plum pox virus (PPV) were chosen to investigate the role of seeds in the epidemiology of this dangerous pathogen. All the considered plants showed typical symptoms on leaves and fruits and were positive in enzyme-linked immunosorbent assay (ELISA). The virus was characterized by immunocapture reverse transcription-polymerase chain reaction (IC-RT-PCR) followed by restriction fragment length polymorphism (RFLP) analysis with RsaI enzyme as a PPV-D isolate. The presence of PPV was checked on fully ripe seeds and seedlings. One half of the seed stock was analysed immediately by ELISA and IC-RT-PCR tests: the cotyledons containing also the embryo were separated from the teguments. The other half of the seed stock was germinated and maintained in an insect-proof screenhouse over a 2-year period. PPV was detected by ELISA only in the seed coat while by IC-RT-PCR also in cotyledons. Seedlings from infected seeds did not show any typical symptoms and were PPV-negative in serological and molecular assays. So far, the presence of PPV in seeds seems to play no role in its epidemiology.

Influence of dietary vitamins A and E on serum alpha- and gamma-tocopherols, retinol, retinyl palmitate and carotenoid concentrations in Humboldt penguins (Spheniscus humboldti).

Serum retinol, retinyl palmitate, beta-carotene, cryptoxanthin, lutein, alpha-tocopherol and gamma-tocopherol were measured in 18 captive Humboldt penguins (Spheniscus humboldti) prior to and following the removal of Columbia River (CR) smelt (Thaleichthys pacificus) from the diet. Dietary vitamin A was reduced from 59.8 to 13.5 IU g-1 (dry matter basis) when CR smelt was removed from the diet. Minimal changes were noted in dietary vitamin E. Serum samples Without-CR smelt had significantly lower circulating retinol (1.19 +/- 0.09 vs. 1.94 +/- 0.08 micrograms ml-1) and retinyl palmitate (0.033 +/- 0.012 vs. 0.105 +/- 0.004 microgram ml-1) compared to samples With-CR. The Without-CR smelt diet resulted in increased serum alpha-tocopherol from 26.4 +/- 0.94 to 39.1 +/- 3.72 micrograms ml-1. More serum samples taken Without-CR smelt had detectable levels of gamma-tocopherol than those With-CR smelt. Serum lutein was higher for the samples taken Without versus With-CR smelt. Serum cryptoxanthin did not differ. beta-Carotene was not detected. Data indicate that high levels of dietary vitamin A can affect circulating levels of retinol, retinyl palmitate and vitamin E. Thus, dietary vitamin A and the interrelationship between vitamins A and E should be considered when assessing captive penguins.