Publications

Chronic obstructive pulmonary disease (COPD), the fourth leading cause of death, seems to be increasing in worldwide prevalence, and carries with it a significant health and economic burden. Smoking cessation is the only available intervention proven to halt disease progression. The authors discuss the role of the newly approved agent, varenicline, in promotion of smoking cessation. The remainder of presently available therapies treat the symptoms of COPD, but do not impact progression of disease. As the understanding of the pathogenesis of COPD improves, new targets for therapies are emerging. Given the large number of potential targets and the results of recent studies, it seems unlikely that a single new agent will result in a cure. Rather, management of COPD should involve a multi-pronged approach including smoking cessation, bronchodilators, treatment of infection, and eventual targeting of inflammatory pathways and genetic predispositions. In this article, the authors discuss presently available therapies as well as agents under development.

Fractionation of cytosolic sphingosine kinase (SKase) activity by gel filtration chromatography gave rise to a 96-kDa peak that contained only the SK2 form of SKase (by Western analysis) and a broad ca. 46 kDa peak that contained only SK1 forms. SK2 appeared to have a bound accessory protein. When tested with the classic SKase inhibitor dimethylsphingosine (DMS), SK1 was extensively inhibited; however, SK2 was not inhibited but unexpectedly was activated. Activation of SK2 was the result of DMS enhancing the affinity of the enzyme for sphingosine, and, at low concentrations of ATP and sphingosine, activated by more than 100%. Activation of SK2 could be demonstrated in the cytosolic fraction indicating it was unrelated to the purification step. The immunomodulator FTY720 also activated SK2 (although to a lesser extent), but was a potent inhibitor of SK1. SK2 from rat liver and spleen was also not inhibited by DMS. L-Sphingosine and to a lesser extent dihydrosphingosine and phytosphingosine were effective inhibitors of both forms.

Persons with chronic disease experience multiple symptoms. Understanding the association between these symptoms and health outcomes would facilitate a targeted approach to symptom assessment and treatment. Our objectives were to determine the association of a range of symptoms with quality of life, self-rated health, and functional status among chronically ill adults, and to assess methods for evaluating the independent associations of symptoms that may be interrelated. We consecutively enrolled 226 cognitively intact, community-dwelling adults, aged 60 years or older with chronic obstructive pulmonary disease, heart failure, or cancer. Seven symptoms (physical discomfort, pain, fatigue, problems with appetite, feelings of depression, anxiety, and shortness of breath) assessed using the Edmonton Symptom Assessment Scale were examined for their association with self-rated quality of life, self-rated health, and functional status. Principal component analysis and logistic regression revealed similar results. The latter demonstrated that physical discomfort was associated with lower self-rated health (adjusted odds ratio [OR] 1.9; 95% confidence interval 1.2-2.9) and functional disability (adjusted OR 1.8; 95% confidence interval 1.2-2.7). Feelings of depression were associated with poorer quality of life (adjusted OR 1.7; 95% confidence interval 1.1-2.6), and shortness of breath was associated with lower self-rated health (adjusted OR 1.5; 95% confidence interval 1.1-2.0). The association between a range of symptoms and quality of life, self-rated health, and functional status differed across outcomes, but only three symptoms-physical discomfort, feelings of depression, and shortness of breath-maintained their associations when multiple symptoms were examined concurrently. These findings suggest that interventions targeting these symptoms could improve several health-related outcomes.