Tufts University

About: Tufts University is a education organization based out in Medford, Massachusetts, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 32800 authors who have published 66881 publications receiving 3451152 citations. The organization is also known as: Tufts College & Universitatis Tuftensis.

Effect of Pharmacotherapy on Rate of Decline of Lung Function in Chronic Obstructive Pulmonary Disease Results from the TORCH Study

Abstract: Rationale: Chronic obstructive pulmonary disease (COPD) is characterized by an accelerated decline in lung function. No drug has been shown conclusively to reduce this decline. Objectives :I n apost hoc analysis of the Toward a Revolution in COPD Health (TORCH) study, we investigated the effects of combined salmeterol 50 mg plus fluticasone propionate 500 mg, either component alone or placebo, on the rate of post-bronchodilator FEV1 decline in patients with moderate or severe COPD. Methods: A randomized, double-blind, placebo-controlled study was conducted from September 2000 to November 2005 in 42 countries. Of 6,112 patients from the efficacy population, 5,343 were included in this analysis. Measurements and Main Results: Spirometry was measured every 24 weeks for 3 years. There were 26,539 on-treatment observations. The adjusted rate of decline in FEV1 was 55 ml/year for placebo, 42 ml/year for salmeterol, 42 ml/year for fluticasone propionate, and 39 ml/year for salmeterol plus fluticasone propionate. Salmeterol plus fluticasone propionate reduced the rate of FEV1 decline by 16 ml/ year compared with placebo (95% confidence interval [CI], 7–25;P , 0.001). The difference was smaller for fluticasone propionate and salmeterol compared with placebo (13 ml/year; 95% CI, 5–22; P 5 0.003). Rates of decline were similar among the active treatment arms. FEV1 declined faster in current smokers and patients with a lower body mass index, and varied between world regions. Patients who exacerbated more frequently had a faster FEV1 decline. Conclusions: Pharmacotherapy with salmeterol plus fluticasone propionate, or the components, reduces the rate of decline of FEV1 in patients with moderate-to-severe COPD, thus slowing disease progression. Clinical trial (GSK Study Code SCO30003) registered with www. clinicaltrials.gov (NCT00268216).

Mouse model of angiogenesis.

Abstract: Neovascularization of ischemic muscle may be sufficient to preserve tissue integrity and/or function and may thus be considered to be therapeutic. The regulatory role of vascular endothelial growth factor (VEGF) in therapeutic angiogenesis was suggested by experiments in which exogenously administered VEGF was shown to augment collateral blood flow in animals and patients with experimentally induced hindlimb or myocardial ischemia. To address the possible contribution of postnatal endogenous VEGF expression to collateral vessel development in ischemia tissues, we developed a mouse model of hindlimb ischemia. The femoral artery of one hindlimb was ligated and excised. Laser Doppler perfusion imaging (LDPI) was employed to document the consequent reduction in hindlimb blood flow, which typically persisted for up to 7 days. Serial in vivo examinations by LDPI disclosed that hindlimb blood flow was progressively augmented over the course of 14 days, ultimately reaching a plateau between 21 and 28 days. Morphometric analysis of capillary density performed at the same time points selected for in vivo analysis of blood flow by LDPI confirmed that the histological sequence of neovascularization corresponded temporally to blood flow recovery detected in vivo. Endothelial cell proliferation was documented by immunostaining for bromodeoxyuridine injected 24 hours before each of these time points, providing additional evidence that angiogenesis constitutes the basis for improved collateral-dependent flow in this animal model. Neovascularization was shown to develop in association with augmented expression of VEGF mRNA and protein from skeletal myocytes as well as endothelial cells in the ischemic hindlimb; that such reparative angiogenesis is indeed dependent upon VEGF up-regulation was confirmed by impaired neovascularization after administration of a neutralizing VEGF antibody. Sequential characterization of the in vivo, histological, and molecular findings in this novel animal model thus document the role of VEGF as endogenous regulator of angiogenesis in the setting of tissue ischemia. Moreover, this murine model represents a potential means for studying the effects of gene targeting on nutrient angiogenesis in vivo.

Endothelial Dysfunction in Pulmonary Hypertension

Abstract: The pathogenesis of pulmonary hypertension (PH) involves a complex and multifactorial process. Endothelial dysfunction seems to play an integral role in mediating the structural changes in the pulmonary vasculature. Disordered endothelial cell proliferation along with concurrent neoangiogenesis, when exuberant, results in the formation of glomeruloid structures known as the plexiform lesions, which are common pathological features of the pulmonary vessels of patients with pulmonary arterial hypertension (PAH). In addition, an altered production of various endothelial vasoactive mediators, such as NO, prostacyclin, endothelin-1 (ET-1), serotonin, and thromboxane, has been increasingly recognized in patients with PH. Because most of these mediators affect the growth of the smooth muscle cells, an alteration in their production may facilitate the development of pulmonary vascular hypertrophy and structural remodeling characteristic of PH. It is conceivable that the beneficial effects of many of the treatments currently available for PAH, such as the use of prostacyclin, NO, and ET antagonists, result at least in part from restoring the balance between these mediators. However, the ultimate cellular and physiological targets of these treatments remain unknown. In addition to the potential consequences of an imbalance in the endothelial production of various mediators, injury to the endothelium may expose the underlying vascular tissue to diverse blood-borne factors that may further promote pathological changes. Endothelial dysfunction may also have adverse consequences on pulmonary vascular hemostasis by altering the production of anticoagulant factors. Recent reports of genetic mutations in the endothelial cells of patients with PH further underscore the role of these cells in the disease pathogenesis. The endothelium lining the normal lung is characterized by significant heterogeneity. Not only is it vastly different from systemic endothelium in ultrastructure and function, but it varies in various vessel types in the pulmonary vasculature itself.1 The main functions of the pulmonary endothelium include maintenance …

Inactivation of the p34cdc2-cyclin B complex by the human WEE1 tyrosine kinase.

Abstract: Entry into mitosis in Schizosaccharomyces pombe is negatively regulated by the wee1+ gene, which encodes a protein kinase with serine-, theonine-, and tyrosine-phosphorylating activities. The wee1+ kinase negatively regulates mitosis by phosphorylating p34cdc2 on tyrosine 15, thereby inactivating the p34cdc2-cyclin B complex. The human homolog of the wee1+ gene (WEE1Hu) was overproduced in bacteria and assayed in an in vitro system. Unlike its fission yeast homolog, the product of the WEE1Hu gene encoded a tyrosine-specific protein kinase. The human WEE1 kinase phosphorylated the p34cdc2-cyclin B complex on tyrosine 15 but not on threonine 14 in vitro and inactivated the p34cdc2-cyclin B kinase. This inhibition was reversed by the human Cdc25C protein, which catalyzed the dephosphorylation of p34cdc2. These results indicate that the product of the WEE1Hu gene directly regulates the p34cdc2-cyclin B complex in human cells and that a kinase other than that encoded by WEE1Hu phosphorylates p34cdc2 on threonine 14.

High-density lipoprotein binding to scavenger receptor-BI activates endothelial nitric oxide synthase

Abstract: Atherosclerosis is the primary cause of cardiovascular disease, and the risk for atherosclerosis is inversely proportional to circulating levels of high-density lipoprotein (HDL) cholesterol. However, the mechanisms by which HDL is atheroprotective are complex and not well understood. Here we show that HDL stimulates endothelial nitric oxide synthase (eNOS) in cultured endothelial cells. In contrast, eNOS is not activated by purified forms of the major HDL apolipoproteins ApoA-I and ApoA-II or by low-density lipoprotein. Heterologous expression experiments in Chinese hamster ovary cells reveal that scavenger receptor-BI (SR-BI) mediates the effects of HDL on the enzyme. HDL activation of eNOS is demonstrable in isolated endothelial-cell caveolae where SR-BI and eNOS are colocalized, and the response in isolated plasma membranes is blocked by antibodies to ApoA-I and SR-BI, but not by antibody to ApoA-II. HDL also enhances endothelium- and nitric-oxide-dependent relaxation in aortae from wild-type mice, but not in aortae from homozygous null SR-BI knockout mice. Thus, HDL activates eNOS via SR-BI through a process that requires ApoA-I binding. The resulting increase in nitric-oxide production might be critical to the atheroprotective properties of HDL and ApoA-I.