Long-term effects of inhaled nicotine.

Tobacco smoking has been reported to be associated with increased risk of cardiovascular disease and cancer, particularly of the lungs. In spite of extensive research on the health effects of tobacco smoking, the substances in tobacco smoke exerting these negative health effects are not completely known. Nicotine is the substance giving the subjective pleasure of smoking as well as inducing addiction. For the first time we report the effect on the rat of long-term (two years) inhalation of nicotine. The rats breathed in a chamber with nicotine at a concentration giving twice the plasma concentration found in heavy smokers. Nicotine was given for 20 h a day, five days a week during a two-year period. We could not find any increase in mortality, in atherosclerosis or frequency of tumors in these rats compared with controls. Particularly, there was no microscopic or macroscopic lung tumors nor any increase in pulmonary neuroendocrine cells. Throughout the study, however, the body weight of the nicotine exposed rats was reduced as compared with controls. In conclusion, our study does not indicate any harmful effect of nicotine when given in its pure form by inhalation.

The amino acid sequence of serum amyloid A (SAA) protein in mink.

The amino acid sequence of serum amyloid A (SAA) protein from mink was established by characterization of peptides derived from digestion of the protein with trypsin and from cleavage with BNPS-skatole. In three positions, two amino acid residues were found, showing that the protein is polymorphic. In position 10 both valine and isoleucine were found, while only valine was observed in protein AA. Prominent sequence homologies with protein SAA and protein AA from other species were seen, particularly corresponding to the segment between positions 31 and 54, but also in the C-terminal part of protein SAA, which is not shared by protein AA.