Tissue damage in the amyloidoses: Transthyretin monomers and nonnative oligomers are the major cytotoxic species in tissue culture

The transthyretin (TTR) amyloidoses are human diseases in which the misfolded TTR protein aggregates in tissues with subsequent visceral, peripheral, and autonomic nerve dysfunction. Recent reports have stressed the importance of oligomeric intermediates as major cytotoxic species in various forms of amyloidogenesis. We have examined the cytotoxic effects of several quaternary structural states of wild-type and variant TTR proteins on cells of neural lineage. TTR amyloid fibrils and soluble aggregates >100 kDa were not toxic. Incubation of TTR under the conditions of the cell assay and analysis by size-exclusion chromatography and SDS/PAGE reveal that monomeric TTR or relatively small, rapidly formed aggregates of a maximum size of six subunits were the major cytotoxic species. Small molecules that stabilize the native tetrameric state were shown to prevent toxicity. The studies are consistent with a model in which the misfolded TTR monomer rapidly aggregates to form transient low molecular mass assemblies (<100 kDa) that are highly cytotoxic in tissue culture

Spectroscopic and structural investigations reveal the signaling mechanism of a luminescent molybdate sensor

A heteroditopic ligand H 2-L consisting of a dihydroxybenzene (catechol)-unit linked via an amide bond to a pyridyl-unit and its methyl-protected precursor Me 2-L were synthesized, characterized, and their photophysical properties investigated. The three accessible protonation states of the ligand, H 2-L+, H 2-L, and H-L-, showed distinct 1 H NMR, absorption and emission spectroscopic characteristics that allow pH-sensing. The spectroscopic signatures obtained act as a guide to understand the signaling mechanism of the luminescent pH and molybdate sensor [Re-(bpy)(CO) 3(H 2-L)]+. It was found that upon deprotonation of the 2-hydroxy group of H 2-L, a ligand-based absorption band emerges that overlaps with the Re(dπ)-bpy metal-to-ligand charge transfer (MLCT) band of the sensor, reducing the quantum yield for emission on excitation in the 370 nm region. In addition, deprotonation of the catechol-unit leads to quenching of the emission from the Re(dn)→ bpy 3MLCT state, consistent with photoinduced electron transfer from the electron-rich, deprotonated catecholate to the Re-based luminophore. Finally, reaction of 2 equiv of [Re(bpy)(CO) 3(H 2-L)]+ with molybdate was shown to give the zwitterionic Mo(VI) complex [MoO 2{Re(CO) 3-(bpy)(L)} 2], as confirmed by electrospray ionization (ESI) mass spectrometry and X-ray crystallography. The crystal structure determination revealed that two fully deprotonated sensor molecules are bound via their oxygen-donors to a cis-dioxo-MoO 2 center

Spectroscopic and structural investigations reveal the signaling mechanism of a luminescent molybdate sensor

A heteroditopic ligand H 2-L consisting of a dihydroxybenzene (catechol)-unit linked via an amide bond to a pyridyl-unit and its methyl-protected precursor Me 2-L were synthesized, characterized, and their photophysical properties investigated. The three accessible protonation states of the ligand, H 2-L+, H 2-L, and H-L-, showed distinct 1 H NMR, absorption and emission spectroscopic characteristics that allow pH-sensing. The spectroscopic signatures obtained act as a guide to understand the signaling mechanism of the luminescent pH and molybdate sensor [Re-(bpy)(CO) 3(H 2-L)]+. It was found that upon deprotonation of the 2-hydroxy group of H 2-L, a ligand-based absorption band emerges that overlaps with the Re(dπ)-bpy metal-to-ligand charge transfer (MLCT) band of the sensor, reducing the quantum yield for emission on excitation in the 370 nm region. In addition, deprotonation of the catechol-unit leads to quenching of the emission from the Re(dn)→ bpy 3MLCT state, consistent with photoinduced electron transfer from the electron-rich, deprotonated catecholate to the Re-based luminophore. Finally, reaction of 2 equiv of [Re(bpy)(CO) 3(H 2-L)]+ with molybdate was shown to give the zwitterionic Mo(VI) complex [MoO 2{Re(CO) 3-(bpy)(L)} 2], as confirmed by electrospray ionization (ESI) mass spectrometry and X-ray crystallography. The crystal structure determination revealed that two fully deprotonated sensor molecules are bound via their oxygen-donors to a cis-dioxo-MoO 2 center

Alcohol-related adverse consequences: cross-cultural variations in attribution process among young adults

Background: Social norms around what is culturally accepted in terms of alcohol consumption and drunken comportment appear important regarding the acceptance of alcohol-related adverse consequences; however, investigations often neglect to consider differences in terms of attribution. This study aims at assessing cross-cultural differences in the reporting of alcohol-related adverse consequences. It also considers differences across consequences that might explain which type of consequences (mainly acute or mainly chronic) are most affected by an attribution process. Methods: Conditional regression models were estimated based on data from eight European countries participating in the Gender, Alcohol and Culture—An International Study (GENACIS) project. Cases were matched to controls based on usual drinking patterns in order to control for average volume of alcohol and frequency of ‘risky single occasion drinking’ (RSOD). Results: Differences among the patterns of associations between countries and consequences were evident. The distinction between Nordic and other European countries was persistent. A higher variability of associations was observed for some consequences, namely the mainly acute instances. Finally, the Isle of Man and Switzerland showed specific trends with associations across consequences. Conclusion: Reporting of alcohol-related adverse consequences seemed strongly affected by cultural norms. The latter may be exemplified by viewing drinking as ‘time-out’ behaviour. Respondents in countries with a stereotypical history of being ‘dry’ or with a stereotyped ‘binge’ drinking culture were more likely to attribute consequences to their alcohol consumption than people in ‘wet’ countries. This was particularly true for consequences that related to episodic ‘time-out’ heavy drinking

The shared CTLA4-ICOS risk locus in celiac disease, IgA deficiency and common variable immunodeficiency

Linkage and association of CD with CTLA4-ICO