The prevalence of pituitary adenomas in the study population (one case in 1064 individuals) was more than 3.5-5 times that previously reported. This increased prevalence may have important implications when prioritizing funding for research and treatment of pituitary adenomas.

Four Holstein steers (208 kg) with "T" cannulas in the rumen and proximal duodenum were used in a 4 x 4 Latin square design experiment to evaluate the interaction of feed intake level on comparative ruminal and total tract digestion of dry-rolled and steam-flaked corn. The basal diet contained (DM basis) 6% alfalfa hay, 6% sudangrass hay, 75% corn, 2% yellow grease, 5% cottonseed meal, 3% cane molasses, and 3% supplement. The corn portion of the diet was provided as either dry-rolled (density = .54 kg/L) or steam-flaked (density = .36 kg/L). Dry matter intake was restricted to allow for .64 vs 1.28 kg/d of weight gain (1.6 vs 2.4% of BW). Ruminal digestibility of OM, starch, and feed N were not affected (P > .10) by DMI. Postruminal digestion of OM and N and total tract digestibility of OM and DE decreased (P < .05) as DMI was increased. Total tract starch digestibility was not influenced (P > .10) by DMI. Steam flaking corn increased (P < .05) ruminal digestibility of OM and starch and postruminal and total tract digestibility of OM, starch, N, DE, and ME. Increasing DMI and steam flaking decreased (P < .05) ruminal pH and molar proportion of acetate. It is concluded that corn processing is the primary factor influencing site and extent of starch digestion. Decreasing DMI increases DE value of the diet; however, ME value is not affected because of increased energy loss as methane.

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The effects of waterborne uranium (U) exposure on gene expression were examined in four organs (brain, liver, skeletal muscles, and gills) of the zebrafish (Danio rerio). Adult male fish were exposed to three treatments: No added uranium (control), 23 +/- 6 microg U/L, and 130 +/- 34 microg U/L. After 3, 10, 21, and 28 d of exposure and an 8-d depuration period, gene expression and uranium bioaccumulation were analyzed. Bioaccumulation decreased significantly in liver during the depuration phase, and genes involved in detoxification, apoptotic mechanism, and immune response were strongly induced. Among these genes, abcb311, which belongs to the adenosine triphosphate (ATP)-binding cassette transporter family, was induced 4- and 24-fold in organisms previously exposed to 23 +/- 6 and 130 +/- 34 microg U/L, respectively. These results highlight the role of liver in detoxification mechanisms. In gills, at the highest uranium concentration, gpx1a, cat1, sod1, and sod2 genes were up-regulated at day 21, indicating the onset of an oxidative stress. Mitochondrial metabolism and DNA integrity also were affected, because coxI, atp5f1, and rad51 genes were up-regulated at day 21 and during the depuration phase. In skeletal muscles, coxI, atp5f1, and cat were induced at day 3, suggesting an impact on the mitochondrial metabolism and production of reactive oxygen species. In brain, glsI also was induced at day 3, suggesting a need in the glutamate synthesis involved with neuron transmission. No changes in gene expression were observed in brain and skeletal muscles at days 21 and 28, although bioaccumulation increased. During the depuration phase, uranium excretion was inefficient in brain and skeletal muscles, and expression of most of the tissue-specific genes was repressed or unchanged.

Experiments were carried out on adult male zebrafish (Danio rerio) to assess early changes induced by waterborne exposure to different isotopic compositions of uranium (depleted uranium associated or not with 233U). Oxidative stress and neurotoxicity were selected as effect endpoints to characterize uranium chemo- and radiotoxicity. Catalase, glutathione peroxidase, and superoxide dismutase activities and total glutathione content of hepatic extracts, as well as brain acetylcholinesterase activity and uranium bioaccumulation, were measured. Oxidative stress induced by uranium exposure led to decreases in superoxide dismutase and catalase activity levels as well as total glutathione content in liver extracts. These perturbations were significantly more marked in 233U-exposed fish. Furthermore, significant increase in acetylcholinesterase activity was observed in brain extracts at the same level, whatever the isotopic composition of uranium.

The influence of time, ambient concentration, and medium composition on selenite (Se(IV)) uptake by the unicellular green alga Chlamydomonas reinhardtii has been investigated. The aims of the performed experiments were to describe the kinetics of accumulation, to characterize transport capacities, to identify key nutrients influencing absorption, and to establish links between speciation and bioavailability. Our results suggested that the adsorbed fraction was negligible compared to the absorbed one. Over the short time scale considered, the absorption was linear with time, with an estimated conductance of approximately 0.2 nmol/m2/h/nM. Uptake was proportional to ambient levels in a broad range of intermediate concentrations (from nM to microM). However, conductances were higher at low concentrations (< nM) and then decreased with increasing concentrations (> microM). These results suggested that a specific but rapidly saturated transport system was involved at low concentrations, coupled with a nonspecific one that was only saturated at high ambient concentrations (approximately mM). The latter could involve transporters used by anionic macronutrients, which is supported by the fact that increasing sulfate and nitrate concentrations induced significant inhibition of Se(IV) uptake. Finally, Se(IV) speciation changes caused by varying pH did not significantly affect bioavailability.

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