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It has been suggested that the effect of cytokinins in retarding leaf senescence comes about through their incorporation into tRNA. To test this hypothesis, kinetin-8-14C, 6-benzylaminopurine-benzyl-7-14C and adenine-8-3H were applied to detached tobacco leaves, and the nucleic acids were thereafter extracted and chromatographed on MAK columns. Kinetin-8-14C and adenine-8-3H were readily incorporated into RNA in a similar pattern. 6-Benzylaminopurine-benzyl-7-14C was effective in delaying chlorophyll loss but was not incorporated into any nucleic-acid fraction. It is concluded that the possibility of cytokinins retarding leaf senescence by completion of tRNA is not supported.

St. Helena Hospital launched the first US residential stop-smoking program, The St. Helena Center for a Smoke-Free Life, in 1969. This observational report describes the center's treatment outcome rate for using a patient-centered approach to the use of tobacco dependence medications and behavioral treatment for patients who participated in the program from January 1, 2005 through December 31, 2007. A total of 284 patients used long-acting (nicotine patch, bupropion, and varenicline) and/or short-acting medications (nicotine nasal spray, nicotine gum, nicotine lozenge, and nicotine oral inhaler) alone or in combination during treatment and after discharge. Seven patients chose to use no medications. Patients using nicotine patch received a mean ± SD dose of 33.3±15.7 mg of nicotine in 16 hours (range, 5-90 mg). The 12-month 7-day point prevalence smoking abstinence rate after participation in the intensive, 1-week, residential program was 57.0%. Recommendations are discussed for future research and for implementing aspects of the St. Helena program in other treatment settings.