Intravital FRET: Probing Cellular and Tissue Function in Vivo

The development of intravital Förster Resonance Energy Transfer (FRET) is required to probe cellular and tissue function in the natural context: the living organism. Only in this way can biomedicine truly comprehend pathogenesis and develop effective therapeutic strategies. Here we demonstrate and discuss the advantages and pitfalls of two strategies to quantify FRET in vivo—ratiometrically and time-resolved by fluorescence lifetime imaging—and show their concrete application in the context of neuroinflammation in adult mice.     

Heavy metal exposure in patients suffering from electromagnetic hypersensitivity

Background

Risks from electromagnetic devices are of considerable concern. Electrohypersensitive (EHS) persons attribute a variety of rather unspecific symptoms to the exposure to electromagnetic fields. The pathophysiology of EHS is unknown and therapy remains a challenge.

Objectives

Heavy metal load has been discussed as a potential factor in the symptomatology of EHS patients. The main objective of the study was to test the hypothesis of a link between EHS and heavy metal exposure.

Methods

We measured lead, mercury and cadmium concentrations in the blood of 132 patients (n = 42 males and n = 90 females) and 101 controls (n = 34 males and n = 67 females).

Results

Our results show that heavy metal load is of no concern in most cases of EHS but might play a role in exceptional cases.

Conclusions

The data do not support the general advice to heavy metal detoxification in EHS.     

Alpha‐Synuclein Binds to the Inner Membrane of Mitochondria in an α‐Helical Conformation

The human alpha‐Synuclein (αS) protein is of significant interest because of its association with Parkinson's disease and related neurodegenerative disorders. The intrinsically disordered protein (140 amino acids) is characterized by the absence of a well‐defined structure in solution. It displays remarkable conformational flexibility upon macromolecular interactions, and can associate with mitochondrial membranes. Site‐directed spin‐labeling in combination with electron paramagnetic resonance spectroscopy enabled us to study the local binding properties of αS on artificial membranes (mimicking the inner and outer mitochondrial membranes), and to evaluate the importance of cardiolipin in this interaction. With pulsed, twofrequency, double‐electron electron paramagnetic resonance (DEER) approaches, we examined, to the best of our knowledge for the first time, the conformation of αS bound to isolated mitochondria.     

Influence of atmospheric plasma-induced graft polymerization of DADMAC into cotton on dyeing with acid dyes

The primary objective of this work was to generate dyes sites in cotton fiber for acid dyes via free radical graft polymerization of diallyldimethylammonium chloride (DADMAC), to confer cationized cotton, and evaluate the dyeability of the cationized cotton toward acid dyes, which is unprecedented. Plasma-induced graft polymerization of DADMAC on cotton, using different plasma conditions, followed by dyeing with different acid dyes was studied. The color yield of dyed cotton was evaluated using K/S. Light fastness, color change, and staining following accelerated washing cycles were carried out to evaluate the effectiveness of cotton cationization. Cross-section dyed cotton was studied using scanning electron microscopy and showed deep dyeing of acid dyes into cotton fibers. This approach resulted in significant dye uptake into the fibers and considerably reduced the need for effluent treatment.     

The influence of type and token frequency on the acquisition of affixation patterns: Implications for language processing.

Rules, and exceptions to such rules, are ubiquitous in many domains, including language. Here we used simple artificial grammars to investigate the influence of 2 factors on the acquisition of rules and their exceptions, namely type frequency (the relative numbers of different exceptions to different regular items) and token frequency (the number of exception tokens relative to the number of regular tokens). We familiarized participants to either a prefixation pattern (where regulars started with /ZaI/ and exceptions ended with /ZaI/) or a suffixation pattern (where regulars ended with /ZaI/ and exceptions started with /ZaI/). We show that the type and the token frequency of regular items and exceptions influence in different ways what participants can learn. For the exceptions to be learned, they have to occur sufficiently often so that participants can memorize them; this can be achieved by a high token frequency. However, a high token frequency of the exceptions also impaired the acquisition of the regular pattern. In contrast, the type frequency of the patterns seemed to determine whether the regular pattern could be learned: When the type frequency of the regular items was sufficiently high, participants successfully learned the regular pattern even when the exceptions were played so often that 66% of the familiarization items were exceptions. We discuss these findings in the context of general learning mechanisms and the role they may play in language acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mycophenolate mofetil: therapeutic applications in kidney transplantation and immune-mediated renal disease

The inhibition of arylamine N-acetyltransferase (NAT) activity by ibuprofen was determined in a human colon tumour (adenocarcinoma) cell line. Two assay systems were employed, one with cellular cytosols (9000 g supernatant) and the other with intact colon tumour cell suspensions. The NAT activity in a human colon tumour cell line was inhibited by ibuprofen in a dose-dependent manner in both systems, i.e. the greater the concentration of ibuprofen in the reaction, the greater the inhibition of NAT activities in both systems. The data also indicated that ibuprofen decreases the apparent Km and Vmax of NAT enzyme from human colon tumour cells in both systems examined. This report is the first demonstration to show that ibuprofen affects human colon tumour cell NAT activity.     

Forward-bias conduction of Schottky diodes on polysilicon thinfilms

An analysis of forward I-V characteristics for Al Schottky contacts to polycrystalline thin films is presented. Experimental results for lateral structures with various n^- doping levels show the expected twofold exponential characteristics representing a transition from electrode-limited to bulk-limited conduction. At higher doping levels the bulk-limited characteristic is not a perfect exponential. The thermionic emission theory has been modified to include crystallite resistivity between grain boundaries and successfully matches experimental data