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Neuropsychological studies of bipolar disorder reveal deficits in a variety of domains, including affective processing, memory, and sustained attention. These findings are difficult to interpret due to the potential confounding effects of mood-stabilizing medications. The present study aims to compare the cognitive performance of medicated and unmedicated subjects with bipolar depression to healthy control subjects.Unmedicated subjects with bipolar depression (UBD, n = 32), subjects with bipolar depression on therapeutic doses of lithium or valproic acid (MBD, n = 33), and healthy control subjects (HC, n = 52) performed neuropsychological tasks measuring affective processing, visual memory, and sustained attention. Performance measures were covaried with age and mood ratings, where applicable.With regard to affective processing, the MBD group exhibited greater response latency than the UBD and HC groups. For the same task, the MBD group made more omission errors during the happy condition than in the sad condition. On a task of sustained attention, the MBD group made more errors than the HC group. There were no significant group differences on measures of visual memory.Deficits in affective processing were found in the medicated group, while unmedicated subjects appear to be unaffected. In particular, the MBD group made more errors during happy conditions, indicating a potential attentional bias in subjects with bipolar depression on mood-stabilizing medications. The present study also implicates impairment in sustained attention for medicated subjects with bipolar disorder, particularly those with the type II variety.

Leaf composition of the bronze brz) mutant Pea [Pisum sativum L. cv. Sparkle E107 (brz brz)] and its Parent genotype (cv-Sparkle) have been compared when grown in nutrient culture, but not when grown in soil where pH has been adjusted to reduce readily available Fe and Mn. Both genotypes were grown in a growth chamber in five soils that differed in pH and DTPA-extractable Fe and Mn. The brz genotype accumulated very high, and often toxic, concentrations of Fe and Mn when grown in acidic soils, while Sparkle did not. Liming reduced leaf-Fe and leaf-Mn concentrations in the brz mutant, but Fe toxicity symptoms were still evident in older leaves. In the acidic soils, leaves of the brz plants also accumulated significantly more Zn, Cu, Ca, Mg, K, Na, Al, and P than did leaves of Sparkle plants. Roots of the brz genotype depressed soil pH by several tenths of a pH unit more than did roots of Sparkle. In contrast to result obtained in the acidic and near-neutral soils, the brz mutant and its parent grew similarly in a calcareous soil (pH 8.2), which contained low concentrations of DTPA-extractable Fe and Mn. In conclusion, the brz mutant Pea consistently accumulates high levels of Fe and Mn when these metal ions are present in readily available forms. Liming an acid soil to near-neutral pH did not prohibit the brz mutant from accumulating potentially toxic concentrations of Fe, but growing the mutant in a calcareous soil did

The effect of soil entrapment on the mineral element concentration in potatoes, Solanum tuberosum L., cv ‘Katahdin,’‘Norking Russet’ and ‘Shepody,’was studied. Titanium was used as the marker element to correct for contamination by soil. Soil entrapment was a significant factor contributing to increases in tuber mineral element concentrations due to the presence of soil in the tissue surface, especially for Al and Fe. Among the macroelements, Ca and Mg concentrations showed a significant increase. Among the microelements, the greatest increases in concentration due to entrapment were observed for Al (95%) and Fe (88%), less for Mn (4%), and generally none for Cd, Co, Cu and Zn. Highest concentrations of elements, including (the potentially toxic element) Al, were found in the peel and least in the pith. The three cultivars showed differences in the accumulation of mineral elements in the peel, with the rougher peel showing the greatest soil entrapment. Boiling resulted in significant decreases in macroelements and increases of microelements in the peel. Tubers in this experiment were cultivated on uncontaminated soil. For tubers grown in soils containing appreciable concentrations of nutritionally undesirable mineral elements, peeling before cooking would greatly facilitate their removal.

The trimethylselenonium ion (TMSe⁺) is an important urinary Se metabolite. As an aid to evaluating its role in the natural cycling of Se, these plant studies concerning its uptake from soils or from nutrient solution and its metabolism were undertaken. Wheat (Triticum aestivum L.) and alfalfa (Medicago sativa L.) were grown on Dalton and Lima loam soils (coarse — silty, mixed, mesic Aeric Fragiaquert and fine-loamy mixed, mesic Glossoboric Hapludalf) containing no added Se or added Na₂SeO₃, Na₂SeO₄, or TMSe⁺, with and without a 4-month storage period prior to planting. Wheat only was grown in a separate experiment on Cecil (a clayey, haolinitic, thermic Hapludult) and Lakeland (thermic, coated Typic Quartzipsamment) soils containing similar amounts of these added Se compounds. The Se contents of the wheat and alfalfa grown on the TMSe⁺-treated Luna and Dalton soils were much lower than for the Na₂SeO₃ or Na₂SeO₄ treatments, barley exceeding that for the untreated control. With the Cecil and, especially, the Lakeland soils the Se content of the wheat was considerably above that for the untreated control, greater than that for the Na₂SeO₃ treatment, but considerably less than that for the Na₂SeO₄ treatment. TMSe⁺ added to nutrient solutions was readily absorbed and translocated to the leaves and stems but not the grain of wheat. At concentrations providing 3 mg Se/liter or more of nutrient solution, it caused signs of toxicity resembling those caused by similar concentrations of Se as Na₂SeO₄. Studies on the chemical form of the Se in the wheat suggested that, except for some volatilization, the TMSe⁺ absorbed was not metabolized.

The relationship of zinc (Zn) deficiency to phosphorus (P) toxicity was examined in 'Emerald' okra [Abelmoschus esculentus (L.) Moench] grown for 21 days (D21) in complete nutrient solution and then transferred to treatments with two levels of P (P1, P2 = 250, 2,000 P) and four levels of Zn (Zn1, Zn2, Zn3, Za4 = 0, 0.25, 1, 2 added Zn). No symptoms of "little leaf" or "resetting" developed in any plants. "Mottle leaf" symptoms developed as chlorotic and necrotic patches in the interveinal areas of the older leaves of Zn, plants at P1 and in Zn1, Zn2, and Zn3 plants at P2. Thus, increasing the level of P induced symptoms which were eliminated by adding Zn. Treatments had little effect on dry matter at D45 and D63: at D111, low Zn depressed dry weight of P1 tops and even more markedly depressed dry weight of P2 tops, roots, and fruits. Increasing solution P increased the concentration and amount of P in all plant parts at all harvests. At D45 it also depressed Zn concentrations in all parts of Zn1 plants but in no other Zn treatment and in no treatment at later harvests. At Zn1, leaves had relatively low concentrations of Zn and high concentrations of P. Increasing levels of Zn enhanced their Zn concentrations and depressed their P concentrations; at D45 and D63 they also depressed the concentrations and total amounts of P in tops and whole plants but increased them in roots. Thus Zn deficiency markedly enhanced P absorption by roots, transport to tops, and accumulation in leaves. Concentrations of magnesium in plant organs responded to treatments in the same way as did P but to a smaller degree, particularly in the leaves. No other element measured (Ca, K, Na, Fe, Cu, Mn) responded in the same way. The development and intensity of symptoms in old leaves correlated closely with P concentrations. Leaves with faint symptoms had 0.8% P; those with marked symptoms had > 1.5% P; and dead leaves had nearly 5% P. The intensification of symptoms is attributed to accumulation of P to toxic levels in leaves. It is suggested that Zn deficiency interferes with P metabolism enhancing the amounts of P absorbed by roots and transported to tops: under conditions of high P supply, P accumulates to toxic levels in leaves inducing or accentuating symptoms resembling Zn deficiency. This effect of Zn on P metabolism in roots seems to explain previously puzzling observations in which P treatments enhanced symptoms of Zn deficiency without any reduction in Zn contents of plant tops: there is no need to invoke any effect of P in inactivating Zn in leaves. Additional Index Words: P-Zn interactions, Zn deficiency, Zn requirements, Abelmoschus esculentus (L.) Moench. View complete article To view this complete article, insert Disc 4 then click button8

Selenium, an essential element for animals, is now being added to some livestock diets. The trimethylselenonium ion (TMSe⁺) is an important urinary metabolite of dietary Se. Selenium spillage onto soils is related to its natural cycling and seems important in creating Se excesses or correcting Se deficiencies in soils. Volatilization and fixation of Se from TMSe⁺ was studied using four soils: a Typic Quartzipsamment, an Aeric Fragiaquept, a Typic Hapludult, and a Glossoboric Hapludalf. For volatilization studies, soils treated with TMSe⁺ or TM⁷⁵Se⁺ were placed in a closed system maintained at room temperature and equipped for aeration and collection of volatile Se or ⁷⁵Se, which was determined at intervals over a period of several weeks. Volatilization occurred with all soils, but the rates varied widely. Treating the acid Aeric Fragiaquept with CaCO₃ increased Se volatilization. Treatment with toluene or autoclaving of the Aeric Fragiaquept or the Glossoboric Hapludalf almost completely prevented the volatilization. A nitrogen atmosphere retarded the volatilization in all but the Aeric Fragiaquept soil. In one experiment, the volatilization and fixation of Se added to soils as Na₂⁷⁵SeO₄, Na₂⁷⁵SeO₃, or TM⁷⁵Se⁺ were studied. Volatilization was measured by ⁷⁵Se loss and was observed only when the TM⁷⁵Se⁺ was added, being appreciable only with the Typic Hapludult and Glossoboric Hapludalf soils. Fixation was determined by measuring the ⁷⁵Se not extracted with 0.1 M CaCl₂ or with water, and was greatest for the ⁷⁵Se from the Na₂SeO₃. Fixation of from TM⁷⁵Se⁺ occurred in all soils during a 21-day period to an extent of about 30 to 50% of that added. The data suggest that Se from urinary TMSe⁺ spilled onto soils would generally be soon lost to the atmosphere or fixed and thus become unavailable to plants.