Effects on the accumulation of calcium, magnesium, iron, manganese, copper and zinc of adding the two inorganic forms of selenium to solution cultures of Zea mays.

The addition of selenate or selenite to common fertilizers for crop production could be an effective way of producing selenium-rich food and feed. However, this would be feasible only if the increase in plant selenium (Se) content did not negatively influence the uptake of other essential elements. We therefore need to understand the interactions between Se and other major and trace elements during uptake by the plant. This study aimed to evaluate the influence of inorganic forms of Se on the accumulation of selected macronutrients (Ca and Mg) and micronutrients (Fe, Zn, Mn and Cu). Those essential elements are involved in the oxidative balance of cells. Zea mays seedlings were grown hydroponically in growth chambers in nutrient solutions to which we added 10, 50 or 1000 µg.L(-1) of selenate and/or selenite. Cation accumulation was significantly affected by the addition of 50 µg.L(-1) or 1000 µg.L(-1) Se, but not by the presence of 10 µg.L(-1) of Se in the nutrient solution. The highest concentration (1000 µg.L(-1)) of Se in the nutrient solution affected the accumulation of essential cations in Zea mays: selenate tended to increase the accumulation of Mg, Zn and Mn, whereas a selenate/selenite mixture tended to decrease the accumulation of Ca, Mg, Zn and Mn. Only Fe accumulation was unaffected by Se whatever its form or concentration. Selenium may also affect the distribution of cations on Zea mays. For example, levels of Mg and Zn translocation to the shoots were lower in the presence of selenite.

Evaluation of streamwater composition changes in the Vosges Mountains (NE France): 1955-2005.

In 1995, in the southwestern Vosges Mountains (NE France), 158 of 395 streams (40%) had a pH lower than 5.5 at baseflow. As elsewhere in Europe, acid deposition has decreased since the seventies, as has base cation deposition. In order to assess the response of streamwater to decreasing deposition, we compared their present chemical composition to their former composition. All comparisons showed a decrease in sulphate concentration, which was greater on granite than on sandstone. In addition calcium, magnesium and aluminium concentrations generally decreased. Acidity in streams draining granite decreased in spring, especially during the eighties; decreases were not observed on sandstone. Continuous monitoring of 5 streams since 1998 confirmed that Al concentrations decreased while changes in pH were small. Chemical trends in streams from the Vosges massif fell between those measured in Northern Europe and Central Europe. This study provides the first broad-scale overview of surface water acidification and recovery in France and emphasizes the need for continuous monitoring to assess long-term changes in aquatic ecosystems.

Meso-substituted cationic porphyrins of biological interest. Photophysical and physicochemical properties in solution and bound to liposomes.

A series of cationic porphyrins with 1-4 positive charges are studied: mono(N-methyl-4-pyridyl)triphenylporphine chloride [Mono], cis(N-methyl-4-pyridyl)diphenylporphine chloride [Cis], tri(N-methyl-4-pyridyl)monophenylporphine chloride [Tri] and tetra(N-methyl-4-pyridyl)porphine chloride [Tetra]. Their photophysical properties are measured in small unilamellar vesicles and compared with those in homogeneous solution. Liposomes of L-alpha-dimyristoyl-phosphatidylcholine (100 nm diameter) and L-alpha-dipalmitoyl-phosphatidylcholine (50 nm diameter) in phosphate-buffered saline (pH = 7.4) or D2O 0.15 M NaCl were used. The effect of the medium microheterogeinity is discussed. The triplet quantum yields in liposomes for all the porphyrins are about 0.7, similar to the value obtained for Tetra in aqueous media. The singlet molecular oxygen quantum yields for the hydrophilic compounds Tri and Tetra are greater than those of the hydrophobic ones, Mono and Cis. Also, association constants (KL) of the dyes to liposomes and their localization within the membranes are determined from fluorescence and fluorescence polarization measurements, respectively. KL values are in the range of 10(4)-10(5) M-1 for all the compounds, indicating that hydrophobic and coulombic interactions between porphyrins and liposomes are responsible for the dye association. Fluorescence polarization experiments indicate that Mono and Cis can penetrate into the lipidic phase, and that Tri and Tetra are located near the polar heads of the lipidic molecules.

Facilitating parenting skills in vulnerable families.

Parents regularly seek advice from their health visitor about how to cope with their child's difficult behaviour. Often the health visitor feels she has nothing constructive to offer, writes Norma Angeli et al. Here they describe how one team of health visitors introduced the STEP positive parenting programme, devised in the US, successfully to help parents from all cultures, classes and backgrounds achieve a better relationship with their child.

Psychiatric morbidity associated with screening for breast cancer.

The 28-item GHQ was used to assess psychiatric morbidity in 302 women attending for routine breast cancer screening, 300 women attending for further investigation of a positive screening result and 150 women referred for investigation of breast symptoms. The GHQ-28 was administered on arrival at the relevant clinic and three months later. Medical records were used to determine the outcome of the clinic attendance. Women were classified into routinely screened women, women with false positive screening results, symptomatic women with a benign diagnosis, newly diagnosed cancer patients and previously treated cancer patients. When tested on arrival at the clinic, 25% of routinely screened, 30% of women with false positive results and 35% of symptomatic women with benign conditions were probable cases of psychiatric morbidity. The only statistically significant difference was between the routinely screened and symptomatic benign groups. Levels of anxiety were significantly higher in those with false positive results and in the symptomatic benign group than in the routinely screened. Three months later the prevalence of probable psychiatric morbidity had fallen to 19% in both the routinely screened and those with false positive results but remained significantly higher in the symptomatic benign group (31%). Probable cases of psychiatric morbidity among newly detected cancer patients rose from 34 to 46% over the 3-month period. Among women who had had breast cancer diagnosed in the past prevalence remained at 21%. The prevalence of probable psychiatric morbidity in screened women is similar to that in the general population. Among women referred for further investigation because of a false positive screening result prevalence was only slightly increased and there was no evidence of a sustained increase in anxiety. Provided that delays are kept to a minimum and that women are kept informed, a breast cancer screening programme does not increase psychiatric morbidity. Further research is required in cancer patients to determine whether those diagnosed in asymptomatic women have a higher and more sustained degree of psychiatric morbidity than those diagnosed in women who are aware of symptoms.