The effects of acute passive smoke exposure on endothelium-dependent brachial artery dilation in healthy individuals.

Passive smoking has both short-term and long-term vascular effects. It is not clear whether impairment of endothelial function reflects the acute effects of passive smoke exposure or the chronic effects. The purpose of this study was to assess the hypothesis that short-term exposure to passive smoke impairs endothelium-dependent vasodilation in healthy nonsmokers. Eighteen healthy young never smokers (12 men, 6 women) 21 to 55 years old (mean +/- SD: 34 +/-9 years) underwent ultrasonography measuring baseline brachial-artery diameter and brachial-artery diameter during hyperemia and after sublingual administration of nitroglycerin, twice: in a smoke-free environment, and then in the same environment polluted by 30 to 35 ppm carbon monoxide. Each subject served as his/her control. Carboxyhemoglobin was measured in blood samples of subjects tested. Mean value of carboxyhemoglobin was 0.6 +/-0.5% in a smoke-free environment and 1.4 +/- 0.5% in a smoking environment (p <0.02). Mean values of flow-mediated dilation (FMD) were 12.6% +/- 7.8% in a smoke-free environment versus 6.8 +/- 7.8% in a smoking environment (p <0.01). On the contrary, nitroglycerin-induced vasodilation did not show any statistical difference (21 +/- 9.8% versus 23 +/-1.4%). Finally, the increase of carboxyhemoglobin was related statistically to the impairment of flow-mediated dilation (r = 0.51; p <0.002). Passive smoking impaired flow-mediated vasodilation in healthy never smokers in a smoking environment. The impairment was strongly related to carboxyhemoglobin level.

Minimum cuticular conductance and cuticle features of Picea abies and Pinus cembra needles along an altitudinal gradient in the Dolomites (NE Italian Alps).

Winter desiccation is believed to contribute to stress in coniferous trees growing at the treeline because cuticular conductance increases with altitude. To test whether winter desiccation occurs in high-altitude conifers of the Dolomites (NE Italian Alps), we measured minimum cuticular conductance (g(min)), needle wettability (contact angle) and cuticle thickness in Picea abies (L.) Karst. and Pinus cembra L. needles from December to August. Samples were collected from adult trees along an altitudinal gradient from valley bottom (1050 m a.s.l.) to the treeline (2170 m a.s.l.). The treeline site is one of the highest in the area and is characterized by a generally low wind exposure. Altitude had no effect on g(min) in either species. In P. abies, large seasonal variations in g(min) were recorded but no changes were related to needle age class. Pinus cembra had a low g(min) and appeared to be efficient in reducing needle water losses. There was a significant increase in g(min) with needle aging in P. cembra growing at low altitude that could be related to a shorter needle longevity compared with P. abies. High contact angles (> 110-120 ) suggested the presence of tubular epicuticular waxes on needles of both species. Contact angles were higher (low wettability) in high-altitude needles than in low-altitude needles. By the end of winter, there was no difference in contact angles between needles in the windward and leeward positions. Wax structures transformed toward planar shapes as demonstrated by the decrease in contact angle from winter to summer. In both species, the cuticle was thicker in needles of high-altitude trees than in needles of low-altitude trees and there was no correlation between g(min) and cuticle thickness. Because desiccation resistance did not decrease with altitude in either species, we conclude that they are not susceptible to winter desiccation at the tree line.

Recurrent epidemic hepatitis A associated with consumption of raw shellfish, probably controlled through public health measures.

Between April 1984 and January 1985, in the Italian seaport of Livorno, the annual incidence of serologically confirmed acute hepatitis A doubled to 46 per 100,000 population. The exposure histories of each of 75 jaundiced subjects with serologically confirmed hepatitis A were compared with up to four, randomly chosen-, age-, sex-, and neighborhood-matched controls. Illness was strongly associated with consumption of raw mussels and clams within six weeks of onset of illness. When the two thirds of the subjects who had been exposed were classified according to the frequency with which they had recently consumed any type of raw shellfish, there was a clear dose-response relation. In February 1985, comprehensive control measures were introduced and the annual incidence of hepatitis A fell to 2.3 per 100,000 population, a 10-fold decrease from the preepidemic period.