Repeated neonatal phencyclidine treatment impairs performance of a spatial task in juvenile rats.
The present study was designed to determine whether repeated postnatal blockade of N-methyl-D-aspartate (NMDA) channel produces cognitive deficit in juvenile rats. Rats receive phencyclidine (PCP) intraperitoneally (i.p.) from postnatal Day 5 and continued daily till Day 15. On Day 28, saline- and PCP-treated rats were trained in the Morris water maze task. PCP-treated rats performed as well as the saline-treated rats on the first day of testing, but on the second day of testing they did significantly poorly compared to saline-treated controls. These data suggest that chronic postnatal NMDA channel blockade by PCP impairs processes that enable rats to retain spatial information.
At the present time, cancer chemoprevention trials, especially non-randomised studies, constitute a large part of the scientific literature. Our purpose was to perform a critical analysis of the few randomised trials comparing a group treated with retinoids or carotenoids to an untreated control group or a placebo control group. Only one trial gave convincing results in favor of such chemoprevention, especially concerning the incidence of secondary cancer, at the cost of severe toxicity. Moreover, we have attempted to list the ongoing intervention trials which could provide details on the indications involved for such treatments.