Brain burdens of aluminum, iron, and copper and their relationships with amyloid-β pathology in 60 human brains.

The deposition in the brain of amyloid-β as beta sheet conformers associated with senile plaques and vasculature is frequently observed in Alzheimer’s disease. While metals, primarily aluminum, iron, zinc, and copper, have been implicated in amyloid-β deposition in vivo, there are few data specifically relating brain metal burden with extent of amyloid pathologies in human brains. Herein brain tissue content of aluminum, iron, and copper are compared with burdens of amyloid-β, as senile plaques and as congophilic amyloid angiopathy, in 60 aged human brains. Significant observations were strong negative correlations between brain copper burden and the degree of severity of both senile plaque and congophilic amyloid angiopathy pathologies with the relationship with the former reaching statistical significance. While we did not have access to the dementia status of the majority of the 60 brain donors, this knowledge for just 4 donors allowed us to speculate that diagnosis of dementia might be predicted by a combination of amyloid pathology and a ratio of the brain burden of copper to the brain burden of aluminum. Taking into account only those donor brains with either senile plaque scores ≥4 and/or congophilic amyloid angiopathy scores ≥12, a Cu:Al ratio of <20 would predict that at least 39 of the 60 donors would have been diagnosed as suffering from dementia. Future research should test the hypothesis that, in individuals with moderate to severe amyloid pathology, low brain copper is a predisposition to developing dementia

Detection of dna and p-450s on silver colloidal nanoparticles by surface-enhanced resonance raman scattering (SERRS)

Surface-enhanced resonance Raman scattering (SERRS) is a very sensitive and selective detection method that can be used for the analysis of both DNA and P-450s. A number of factors have limited the broader application of the technique. These limitations are described and addressed. An approach to reduce the problems associated with variation of the silver colloids used to provide surface enhancement and chemical methodologies that ensure surface adsorption are presented. A practical approach was used to investigate the nature of the effect. This approach has highlighted the importance of resonance enhancement for ultimate sensitivity. Two approaches to achieve successful detection of DNA using SERRS are described, and, using these two approaches, the possibility of multiplexing is also demonstrated. The analysis of proteins by SERRS is discussed and P-450 is presented as a specific example of the information that may be gained from SERRS of proteins

Novel SERS-active optical fibers prepared by the immobilization of silver colloidal particles

A novel sensor based upon surface-enhanced Raman scattering (SERS) has been constructed by immobilizing colloidal silver particles onto the distal end of an optical fiber. This same single fiber was then used to both transport the exciting laser radiation and collect the Raman scattering from analytes sorbed onto the colloidal particles. The colloidal particles were immobilized by functionalization of the end of the optical fiber with (3-am inopropyl)trimethoxysilane prior to immersion of the fiber in silver colloid. Spectra were obtained from both 4-(5'-azobenzotriazol)3,5-dimethoxyphenylamine and crystal violet. The within-batch variation of a set of five fibers has been measured as approximately 10%. Raman imaging experiments demonstrated that the effects due to spatial variations in the intensity of the SERS recorded over the distal end of the fiber are removed by the use of a multimode fiber. Index Headings: Fiber optic; Raman; Surface-enhanced Raman scattering; SERS; Surface-enhanced resonance Raman scattering; SERRS; Sensors

Detection of DNA and P450s on silver colloidal nanoparticles by surface enahnced resonance raman scattering (SERRS)

Surface-enhanced resonance Raman scattering (SERRS) is a very sensitive and selective detection method that can be used for the analysis of both DNA and P-450s. A number of factors have limited the broader application of the technique. These limitations are described and addressed. An approach to reduce the problems associated with variation of the silver colloids used to provide surface enhancement and chemical methodologies that ensure surface adsorption are presented. A practical approach was used to investigate the nature of the effect. This approach has highlighted the importance of resonance enhancement for ultimate sensitivity. Two approaches to achieve successful detection of DNA using SERRS are described, and, using these two approaches, the possibility of multiplexing is also demonstrated. The analysis of proteins by SERRS is discussed and P-450 is presented as a specific example of the information that may be gained from SERRS of proteins

Enhanced sandfly attraction to Leishmania-infected hosts

We report that hamsters infected with Leishmania infantum are more attractive to female sandflies in bioassays. Entrained odours from infected animals were shown by gas chromatography to contain peaks absent from uninfected individuals. Implications of enhanced transmission, potential for developing novel diagnoses and the significance to epidemiological models are discussed