Direct evidence for the ring opening of monosaccharide anions in the gas phase: photodissociation of aldohexoses and aldohexoses derived from disaccharides using variable-wavelength infrared irradiation in the carbonyl stretch region.

All eight D-aldohexoses and aldohexoses derived from the non-reducing end of disaccharides were investigated by variable-wavelength infrared multiple-photon dissociation (IRMPD) as anions in the negative-ion mode. Spectroscopic evidence supports the existence of a relatively abundant open-chain configuration of the anions in the gas phase, based on the observation of a significant carbonyl absorption band near 1710 cm(-1). The abundance of the open-chain configuration of the aldohexose anions was approximately 1000-fold or greater than that of the neutral sugars in aqueous solution. This provides an explanation as to why it has not been possible to discriminate the anomeric configuration of aldohexose anions in the gas phase when derived from the non-reducing sugar of a disaccharide. Evidence from photodissociation spectra also indicates that the different aldohexoses yield product ions with maximal abundances at different wavelengths, and that the carbonyl stretch region is useful for differentiation of sugar stereochemistries. Quantum-chemical calculations indicate relatively low energy barriers to intramolecular proton transfer between hydroxyl groups and adjacent alkoxy sites located on open-chain sugar anions, suggesting that an ensemble of alkoxy charge locations contributes to their observed photodissociation spectra. Ring opening of monosaccharide anions and interconversion among configurations is an inherent property of the ions themselves and occurs in vacuo independent of solvent participation.

[Changes in the content of carbohydrate-containing proteins in the liver of rats chronically exposed to pesticides combined with total gamma irradiation]. / Izmenenie soderzhaniia uglevodsoderzhashchikh belkov v pecheni krys pri khronicheskom ikh porazhenii pestitsidami v sochetanii s obshchim gamma-oblucheniem.

A study was made of the chronic effect of pesticides, within a wide range of doses, combined with whole-body gamma-irradiation, on the content of carbohydrate-containing proteins of rat liver. The extent to which disturbances in the carbohydrate-containing protein metabolism were manifest was shown to depend upon dose and time of action of the damaging factors. As determined by certain parameters, the combined effect of pesticides and gamma-radiation at the biochemical level was additive, and it was more than additive as estimated by a number of other tests.

Radiation nephritis. 3. Chemical, functional and morphologic correlates of the glomerular basement membrane.

In the rat, radiation injury to a kidney results in severe glomerular lesions, with only a moderate increase in proteinuria. The proteinuria, however, was found to be nonselective. There was no relationship between the degree and selectivity of the proteinuria. No change in the gross chemical composition of the glomerular basement membrane obtained from the irradiated kidney was observed when compared with the GBM of a) untreated control kidneys, b) kidneys obtained from sham operated rats, c) unilaterally nephrectomized and d) control kidneys of irradiated animals. In conclusion, no correlation could be established between the morphologic alterations of the glomerulus and the chemical or permeability characteristics of the membrane.