Tobacco use among Massachusetts youth: is tobacco control working?

BACKGROUND: This paper examines whether the Massachusetts Tobacco Control Program is affecting the rates of smoking and smokeless tobacco use among Massachusetts' youth. METHODS: School survey data from the Massachusetts Prevalence Study were analyzed to estimate differences between 1993 and 1996 rates of youth cigarette and smokeless tobacco use, attitudes toward smoking, and awareness of cigarette ads and promotions of antismoking messages. RESULTS: Lifetime and Current Smoking rates declined significantly among middle school males, contrasting with stable national trends. Among girls in this age group, Lifetime and Current Smoking did not change significantly. Hispanic middle school students exhibited a significant decline in Lifetime Use. There were no significant changes in Lifetime or Current Smoking rates among high school students. Lifetime use of smokeless tobacco declined among middle school students while Current Use declined among both middle and high school students. Students reported declines in awareness of cigarette ads or promotions and increases in awareness of antismoking messages. CONCLUSIONS: These results provide evidence for cautious optimism regarding the impact of tobacco control, but indicate that these efforts should begin earlier and that additional research is needed to understand and address the problems of tobacco use by girls.

Reproduction of waxed functional occlusal patterns in fired ceramics.

A useful procedure allows reproduction of ideally waxed-up occlusions in typical fixed ceramics. For skilled laboratory technicians this procedure will be adaptable to some restorations.

A temperature-sensitive change in the energy of activation of hormone-stimulated hepatic adenylyl cyclase.

We describe an abrupt increase (at 32 degrees ) in the energy of activation for the reaction of hepatic adenylyl cyclase in the presence of glucagon or epinephrine. This increase is not seen in the presence of fluoride, prostaglandin E(1), or 1-propanol, or in the absence of cyclase stimulators. The change in energy of activation found with hormones is abolished by 1-propanol. This change does not represent differences in hormone or substrate binding at different temperatures, but seems to reflect interactions among elements of the cyclase stimulation sequence. Similar changes in energy of activation were not observed for alkaline phosphatase, cyclic AMP-phosphodiesterase, 5'-nucleotidase, or ouabain-sensitive ATPase. Since the mole fraction of cholesterol in liver membranes is sufficiently high to preclude a phase change in bulk membrane lipids, our observation suggests either that cyclase is restricted to cholesterol-poor membrane regions or that the change in its energy of activation is largely restricted to protein components of the cyclase apparatus. The data are compatible with fundamental differences in the stimulation process(es) for the hormones (glucagon and epinephrine) as compared with those for fluoride and prostaglandin E(1).

Biochemical characterization and cytochemical localization of a catecholamine-sensitive adenylate cyclase in isolated capillary endothelium.

Capillaries were isolated from epididymal fat, and a catecholamine-sensitive adenylate cyclase found in these capillaries was characterized. The effect of various hormones on the accumulation of adenosine 3':5'-cyclic monophosphate in capillary endothelial cells was determined and the cyclase was found to exhibit mixed alpha and beta characteristics. Cyclase was cytochemically localized in these endothelial cells with 5'-adenylyl-imidodiphosphate as a specific cyclase substrate and alloxan as a specific cyclase inhibitor. Lead imidodiphosphate was precipitated at or near the site of cyclase activity upon hydrolysis of 5'-adenylyl-imidodiphosphate by cyclase. This reaction product was observed primarily on the luminal surface of intact capillaries, in micropinocytic invaginations, in free vesicles within the cytoplasm, and in the intracellular junctions.