Ferulic acid is a potent ubiquitous plant antioxidant. Its incorporation into a topical solution of 15%l-ascorbic acid and 1%alpha-tocopherol improved chemical stability of the vitamins (C+E) and doubled photoprotection to solar-simulated irradiation of skin from 4-fold to approximately 8-fold as measured by both erythema and sunburn cell formation. Inhibition of apoptosis was associated with reduced induction of caspase-3 and caspase-7. This antioxidant formulation efficiently reduced thymine dimer formation. This combination of pure natural low molecular weight antioxidants provides meaningful synergistic protection against oxidative stress in skin and should be useful for protection against photoaging and skin cancer.

The presence of estrogen receptor cells in postnatal cerebral cortex and their topographical and numerical changes between birth and postweaning were examined. On postnatal days 0, 2, 8, 12, 18, and 25, six mice (three males and three females) were injected sc with 0.25 microgram/100 g BW 11 beta-methoxy-16 alpha-[125I]iodoestradiol [( 125I]MIE2). Two additional males on postnatal day 2 were each sc injected with 250 micrograms/100 g BW 17 beta-estradiol 1 h before radiolabeled ligand to establish the specificity of nuclear label. Two hours after the injection of [125I]MIE2 brains were frozen, and 4-microns sections were thaw-mounted and processed for autoradiography. Autoradiograms were exposed for 1-45 days, and cortical cells with nuclear uptake and retention of [125I]MIE2 were evaluated at the levels of the frontal pole, preoptic area, and central and posterior hypothalamus. At birth, cells with nuclear label were found predominantly in deep cortical layers. Between birth and postnatal day 2, the number of labeled cells increased in deep and intermediate laminae and first appeared in certain superficial regions. By day 8, labeled cells were concentrated in laminae II-VI of the cingulate/paracingulate and suprarhinal cortex. On day 12, labeling in laminae V and VI declined to a few cells, while a concentration of labeled cells remained in laminae II and III of the cingulate/paracingulate and suprarhinal regions. With subsequent development, an attenuation in labeling at all cortical levels was observed. By day 25, a small cluster of labeled cells remained in lamina II and III of the anterior cingulate, paracingulate, and suprarhinal regions, with additional labeled cells scattered throughout the remaining cortex. Competition with unlabeled 17 beta-estradiol reduced nuclear concentration of ligand in all cortical layers and demonstrated the specificity of [125I]MIE2 for the estrogen receptor. These results show the extensive presence of estrogen target cells in the early postnatal cortex and a profound change in topography and number of target cells during the postnatal period. These findings further suggest an important role for estrogen in the development of certain cortical neurons, possibly involving neuronal differentiation, cell positioning, and connectivity.

Estrogen binding was compared in cell nuclear KCl extracts from microdissected brain regions of gonadectomized-adrenalectomized male and female rats treated with a near-saturating dose of 17 beta-estradiol. Injection of 3.6 or 36.0 micrograms 17 beta-estradiol/kg BW, iv, 1 h before death resulted in a higher level of estrogen binding in the periventricular preoptic area (PVPOA), medial preoptic area, and ventromedial nucleus of the hypothalamus (VMN) of the female than in comparable tissue samples from the male. No significant sex differences in nuclear estrogen binding were observed in the arcuate-median eminence region, bed nucleus of the stria terminalis, or corticomedial amygdala. Scatchard analysis of saturation binding data revealed that the sex differences in cell nuclear estrogen binding in the PVPOA, medial preoptic area, and VMN reflect a difference in binding capacity rather than binding affinity. These in vitro biochemical findings were confirmed by autoradiographic studies. Gonadectomized-adrenalectomized animals were injected with 125I-labeled 11 beta-methoxy-16 alpha-iodoestradiol (2.0 micrograms/kg BW). Thin frozen sections (10 microns) through the preoptic area and hypothalamus were thaw-mounted onto microscope slides, then exposed against LKB Ultrofilm for 21 days. The autoradiographic images exhibited similar silver distributions and densities in males and females in the arcuate-median eminence region bed nucleus of the stria terminalis, and amygdala. However, 11 beta-[125I]methoxy-16 alpha-iodoestradiol uptake was lower in males than in females in the PVPOA and VMN. These results suggest that sex differences in responsiveness to estrogen stimulation in the rat may be due in part to sex differences in estrogen-binding capacity in specific regions of the hypothalamus that play important roles in the control of pituitary function and reproductive behaviors.

Isoflavones provide effective photoprotection and are good candidate ingredients for protection against ultraviolet (UV) photodamage.

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