Interactive effects of lead, copper, nickel and zinc on growth, metal uptake and antioxidative metabolism of Sesbania drummondii.

Sesbania drummondii seedlings were grown in a medium to which lead (Pb), copper (Cu), nickel (Ni) and zinc (Zn) were added singly and in combinations in order to assess the effects of metal interactions on seedling growth, metal accumulation and anti-oxidative system. S. drummondii growth was significantly inhibited with metal treatments. S. drummondii accumulated substantially higher concentrations of metals in the roots than shoots. The uptake of metals followed the order Pb>Cu>Zn>Ni in roots and Pb>Zn>Cu>Ni in shoots. In addition, uptake of a single metal by S. drummondii was affected by the presence of a second metal, suggesting an antagonistic effect or competition between metals at the plant uptake site. A significant increase in both enzymatic [superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR)] and non-enzymatic (glutathione) antioxidant was observed in the S. drummondii seedlings exposed to different metal treatments. The enhancement in enzyme activities followed the order of Cu>Ni>Pb>Zn. However, compared to the effect of individual metal, metals in combination increased the enzyme activities to varying degrees.

Increased amyloid beta protein levels in children and adolescents with Down syndrome.

BACKGROUND: Persons with Down syndrome (DS) (40 years and older) have neuropathological changes characteristic of Alzheimer disease (AD). Soluble forms of amyloid beta (Abeta) peptide generated from amyloid precursor protein (APP) end at C-terminal residues 40 and 42. The presence of the apolipoprotein E (ApoE) epsilon4 allele is a significant risk factor for the development of sporadic AD. Although preliminary studies have shown an association of plasma Abeta42 and ApoE epsilon4 allele in older persons with DS who have dementia, the relationship between plasma Abeta40 and Abeta42 levels and ApoE phenotypes in children with DS has not been examined. Inflammation might play a role in the growth of DS brains. Neopterin is an immune activation marker for the cell-mediated immune response. OBJECTIVE: To examine the levels of plasma Abeta40, Abeta42, and neopterin in children or adolescents with DS or controls. MATERIALS AND METHODS: Blood was collected from DS (N=35; 7+/-3.8 years old) and their siblings (N=34; 10+/-4.5). Plasma Abeta40 and Abeta42, and neopterin levels were quantitated by sandwich ELISA. RESULTS: Abeta40 and Abeta42 levels were higher in DS than controls. The ratio of Abeta42/Abeta40 was lower in DS than in controls. There were significant negative correlations between age and Abeta40 in DS and controls, and between age and Abeta42 levels in DS but not in controls. There was no association of Abeta40 or Abeta42 levels with Apo E in either group. Neopterin levels were higher in DS than controls, and the levels were not correlated with Abeta40 and Abeta42 levels in DS or controls. CONCLUSIONS: The over expression of APP gene in DS leads to increases in plasma Abeta40 and Abeta42 levels before plaque formation in DS brain. Higher neopterin concentrations in DS reflect inflammatory cell activation. Further studies are needed to determine whether DS children with lower plasma Abeta42/Abeta40 ratios are at increased risk of developing AD during aging than those with higher ratios.

Benzidine transformation processes in natural sediments.

Aromatic amines, such as benzidine and 3,3'-dichlorobenzidine, are chemicals used in the pigment and dye processes. Release of these compounds into the environment is important because of their carcinogenic and toxic nature. In the present study, the sediment and water samples were collected from Lake Macatawa (Holland, MI, USA) and subsequently spiked with benzidine. The grain size distribution of the sediment samples investigated here ranged in composition from sandy to silty-clay sediment types. The sediment-water systems spiked with benzidine were incubated under anaerobic conditions at 4, 15, and 23 degrees C for 211 d. Degradation of benzidine was observed over the time-course analysis of the sediment-water mixtures. Three possible metabolites (aniline, 2-ethyl-1-hexanol, and 1-amino-2-hexene) were observed during this investigation as a result of gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry. No metabolites were observed in autoclaved bottles, suggesting that the transformation of benzidine in the sediment-water mixtures was the result of microbial activity. From sediment-water distribution experiments, benzidine demonstrated higher sorption affinity for the different sediment phases than its degradation product, aniline. Therefore, microbially mediated transformation of benzidine to aniline is expected to yield a greater total concentration of the more mobile compound, aniline, in the water phase and a greater possibility for transport of aniline in the water phase.

Down syndrome and comorbid autism-spectrum disorder: characterization using the aberrant behavior checklist.

To report on the cognitive and behavioral attributes of 61 children with Down syndrome (DS) and autistic-spectrum disorder (ASD) according to DSM-IV criteria; to determine the utility of the aberrant behavior checklist (ABC) to characterize these subjects for research purposes; and to test the hypothesis that subjects with DS + ASD could be distinguished from their typical DS peers using the ABC. Cross-sectional design. Cases with DS + ASD (N = 61), comparison group of DS + stereotypy movement disorder (SMD) (N = 26) and typical DS controls without behavior problems (N = 44) were ascertained and enrolled sequentially upon presentation to a DS clinic at an academic medical center over a 10-year period from 1991 to 2001. All subjects underwent neurodevelopmental and medical evaluation, and standardized cognitive testing. The parents provided responses to standardized behavioral questionnaires. Cognitive function (IQ) differed markedly across the three groups. The Lethary and Stereotypy subscales of the ABC were highly significant (P < 0.001) in distinguishing the three groups from one another. Within the ASD group differences were apparent by DSM-IV type on the Lethargy subscale, which reached significance, ANOVA (F = 0.002) and t-test (Autism > PDD, P = 0.005; PDD < CDD, P = 0.002). Using a multivariate regression model, the ABC scales alone explained 62% of variance of ASD outcome; addition of demographic variables explained up to 68% of the variance. There is good correlation between DSM-IV criteria for autism and subscales scores on the ABC in subjects with DS. This study demonstrates the feasibility of using the ABC to characterize the neurobehavioral phenotype of a cohort of children with trisomy 21 and ASD for ongoing research purposes.