RESUMO
In Study 1, ten never-smokers, ten ex-smokers and nine current smokers received nicotine (2 mg) and placebo gum hourly for 4 hours on 2 consecutive days in a randomized, double-blind, cross-over protocol. Dysphoria from nicotine was greatest in never-smokers, intermediate in ex-smokers, and least in current smokers (p less than 0.05). On the third day, subjects were given concurrent access to the same gums and told to chew ad lib. Across all subjects, nicotine was an aversive stimulus (i.e., self-administered less than placebo). Nicotine was avoided most in never-smokers, intermediate in ex-smokers and least in current smokers (p less than 0.05). Study 2 used a similar protocol and compared the nine current smokers in Study 1 who were not told they would receive nicotine with eight informed smokers, i.e., smokers told they would receive nicotine. Although nicotine appeared to be a reinforcer more often in the informed smokers than in the uniformed smokers (63% vs. 22%), this result was not statistically significant. Our results suggest 1) past drug history can influence the stimulus effects of nicotine and 2) the effects of instructions on the response to nicotine may be less in experimental settings than in therapeutic settings.
Assuntos
Nicotina/farmacologia , Reforço Psicológico , Fumar/psicologia , Adulto , Pressão Sanguínea/efeitos dos fármacos , Método Duplo-Cego , Tolerância a Medicamentos , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Nicotina/administração & dosagem , Nicotina/efeitos adversos , Projetos Piloto , Ensaios Clínicos Controlados Aleatórios como Assunto , Autoadministração/psicologia , Fumar/fisiopatologiaAssuntos
9,10-Dimetil-1,2-benzantraceno , Benzo(a)Antracenos , Neoplasias Mamárias Experimentais/metabolismo , tRNA Metiltransferases/metabolismo , Animais , Feminino , Guanina/metabolismo , Glândulas Mamárias Animais/metabolismo , Neoplasias Mamárias Experimentais/induzido quimicamente , Metilação , Gravidez , RNA Bacteriano , RNA de Transferência , Ratos , Ribonucleosídeos/metabolismo , Especificidade por SubstratoRESUMO
Infection of humans with Epstein-Barr virus (EBV) may cause infectious mononucleosis (IM). Analysis of single EBV-infected cells from tonsils of IM patients for rearranged immunoglobulin genes revealed two strategies of EBV for rapid and massive spread in the B cell compartment: the direct infection of many naive as well as memory and/or germinal center B cells and the expansion of the latter cells to large clones. In IM, the generation of virus-harboring memory B cells from naive B cells passing through a germinal center reaction likely plays no role. Members of clones can show distinct morphologies and likely also EBV gene expression patterns, and this ability implies a mechanism by which EBV-harboring cells can evade immune surveillance and establish a pool of persisting EBV-infected B cells.