Estradiol (E2) has been shown to exert organizational, neurotrophic, and neuroprotective effects in the CNS. The present study assessed the specificity of the neuroprotective effects of estradiol for the potent 17␤-isomer. SK-N-SH cells from a human neuroblastoma cell line, which we have shown to be estrogen-responsive, were cultured at low or high plating density. Then cells were exposed to 17␤-E2 (0.2 or 2 nM), 17␣-E2 (0.2 or 2 nM), or cholesterol, testosterone, dihydrotestosterone, progesterone, or corticosterone (all at 2 nM). Cultures were insulted by serum deprivation, which caused a profound loss of cells. At 1 or 2 d of serum deprivation and steroid hormone replacement, the protection afforded cells by the steroid addition was assessed. Serum deprivation killed ϳ90% of cells cultured at both low and high plating density. Both 17␣-and 17␤-E2 provided protection of SK-N-SH cells at either plating density. Further, a 10-fold molar excess of tamoxifen antagonized only approximately one-third of the neuroprotective effects of either isomer of estradiol, and a 100-fold excess of tamoxifen had no additional effect on the neuroprotection by 17␤-E2. By contrast, none of the other steroids tested protected cells from the insult of serum deprivation. These results indicate that the neuroprotective effects of estrogens are not attributable to the general steroid structure, and the majority of the neuroprotection may not be mediated via a tamoxifenantagonized receptor mechanism.

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This report describes the epidemiology, investigation and control of a hepatitis A (HAV) outbreak in New Zealand. Descriptive and analytical epidemiology, virology, product traceback and an orchard investigation were carried out. A case-control study revealed that 56% of 39 cases had consumed raw blueberries, compared with 14% of 71 controls (odds ratio 7.6; 95% confidence intervals 2.6-22.4). Traceback of product through retailers and wholesalers implicated a single commercial orchard. Hepatitis A virus was detected by reverse transcriptase polymerase chain reaction in faecal specimens from cases as well as a blueberry product from the orchard. Presence of hepatitis A virus was confirmed by DNA hybridization and sequencing of PCR products. Sanitary audit of the orchard revealed multiple opportunities for contamination of blueberries by pickers. This outbreak highlights the need for food safety programmes in the berry fruit industry.

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