Smoking cessation among Hong Kong Chinese smokers attending hospital as outpatients: impact of doctors' advice, successful quitting and intention to quit.

To identify factors affecting current smokers' intention to quit smoking and factors associated with successful quitting among ex-smokers in Hong Kong. A cross-sectional survey of Chinese patients attending medical and surgical Specialist Outpatient Clinics (SOPCs) of public hospitals in Hong Kong, using a structured questionnaire. Results of the 642 respondents, 21% were current smokers, 9% were ex-smokers and 69% were non-smokers. 74% of the smokers reportedly received quitting advice from doctors. Among the current smokers, past quitting attempts, receiving information from sources other than doctors, believing that doctor's advice was useful, believing that all smokers should quit smoking and a positive attitude towards quitting were associated with intention to quit. Among those who had attempted to quit, being older (aged 50 or above), being retired/unemployed and consuming more than 10 cigarettes per day were associated with successful quitting. We found that advice from doctors on quitting smoking did not have any impact on Chinese smokers quitting or future intention to quit and reflect the inadequacy of advice given by Hong Kong doctors. The predictors of intention to quit and successful quitting identified in the study could be used to design future smoking cessation services.

Desensitization of adrenomedullin and calcitonin gene-related peptide receptors in vascular smooth muscle cells--effects of receptor activity-modifying protein.

Recent researches suggest that adrenomedullin (ADM) and calcitonin gene-related peptide (CGRP) bind to the same calcitonin receptor-like receptors (CRLR), with receptor specificity being determined by a receptor activity-modifying protein (RAMP). Our objective was to explore the significance of CRLR/RAMP hypothesis in cardiovascular tissues through experiments on the phenomenon of desensitization of both ADM and CGRP receptors using cultured rat aortic vascular smooth muscle cells (VSMCs). VSMCs were incubated for 20 min either in serum-free medium (SFM) alone or in the SFM containing vasoactive agonist [10(-8) mol/L ADM, CGRP and proadrenomedullin (PAMP)]. Cells were washed twice and incubated for another 20 min in SFM containing a repetitive agonist ADM or CGRP and 0.5 mmol/L isobutyryl methylxant (an inhibitor of phosphodiesterase). VSMCs were harvested and assayed for cAMP. Exposure of VSMCs to ADM, CGRP, or PAMP alone increased intracellular cAMP generation by 191% (P < 0.01), 385% (P < 0.01) and 67% (P < 0.05), respectively, compared with SFM group. Pre-treatment of VSMCs to ADM or CGRP decreased cAMP generation in response to subsequent stimulation with CGRP by 44% (P < 0.05) and 48% (P < 0.01), respectively. Pre-treatment of VSMCs with 100 nmol/L H-89, a protein kinase A (PKA) inhibitor, abolished the desensitization of CGRP-acting receptor, implying that this desensitization was mediated through PKA. In contrast, there was no attenuation in cAMP response to stimulation with ADM by pre-exposure to ADM or CGRP. Identical results were seen with or without PKA inhibition by H-89. Pre-exposure of VSMCs to PAMP resulted in no change in cAMP generation in response to subsequent stimulation with ADM or CGRP. These results indicate that ADM receptors do not desensitize in VSMCs in contrast to CGRP-receptors, which are desensitized by pre-exposure to ADM or CGRP. These data also suggest that the desensitization phenomenon of ADM is different from that of CGRP.

[Content and activity of the focal adhesion kinase in cultured vascular smooth muscle cells enhanced by urotensin II].

Urotensin II (U II) is the most potent vasoconstrictor identified in vivo, which plays an important role in the smooth muscle cell proliferation in atherosclerosis. All available information suggests that focal adhesion kinase (FAK) is at the crossroads of multiple signaling pathways and is essential for cell proliferation. But the effect of U II on the FAK mediated signal transduction pathway is unclear. In this study, FAK content and tyrosine phosphorylation were assessed by Western blot and immunoprecipitation in cultured rat vascular smooth muscle cells. Increased protein tyrosine phosphorylation was observed within 5 min of U II 10(-7) (mol/L) addition and was maximal by 30 min, while FAK protein content showed no change during the first 30 min but it increased at 2 h reaching a plateau by 4 h, and decreased after 6 h. In addition, the elevated phosphorylation of FAK was detected upon U II stimulation at 10(-8) mol/L, being maximal at 10(-7) mol/L, but decreased at 10(-6) mol/L. Treatment of the cells with cytochalasin B (50 micromol/L), which disrupted the organization of cytoskeleton, had no influence on the increased FAK tyrosine phosphorylation in response to U sti II mulation. In order to study the relationship between FAK and mitogen-activated protein kinase, calmodulin and protein kinase C, selective inhibitors PD98059 (50 micromol/L), W7 (50 micromol/L) and H7 (50 micromol/L) were added following U II treatment. Neither PD98059 nor W7 influenced the increased FAK tyrosine phosphorylation, but H7 further increased it. These findings indicate that FAK activation is independent of the integrity of cytoskeleton and closely related to protein kinase C, but had no relation with mitogen activated protein kinase and calmodulin.