Solvent, classes exposure, workers

The self-assembling cyclic D,L-cc-peptide nanotubes described demonstrate high stability on surfaces even after two months exposure to ambient temperature. NDI peptide nanotubes 18 may provide a facile method for the preparation of a new class of synthetic biomaterials [16b, 34a]. Recently Sanders and co-workers demonstrated the formation of amino acid-derived NDI hydrogen-bonded supramo-lecular organic M-helical nanotubes in nonpolar solvents and also in the solid state [34b]. The hydrogen-bonded supramolecular nature of the helical nanotubes was confirmed by the circular dichroism (CD) spectrum in chloroform with the addition of methanol, destruction of the supramolecular nanotubes was observed, due to the capabilities of such an aprotic solvent to compete for hydrogen-bond interactions [34b]. 

Renal Effects. Reversible kidney damage has been reported in humans accidentally exposed to acutely toxic amounts of tetrachloroethylene vapors (Hake and Stewart 1977). There are also data that suggest that occupational exposure to hydrocarbon solvents as a class may contribute to chronic renal disease (Kluwe et al. 1984). Subtle renal perturbations have been detected in studies of chronically exposed workers in dry cleaning workshops (Franchini et al. 1983 Mutti et al. 1992 Price et al. 1995 Vyskocil et al. 1990). Mutti et al. (1992) suggested that the observed effects indicated increased shedding of epithelial membrane components from tubular cells, which could be a physiological adaption to exposure or could be an early state of clinically silent renal disease. 

---