Seminars in respiratory and critical care medicine
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Semin Respir Crit Care Med · Dec 2005
ReviewEscalation of antimicrobial resistance among Streptococcus pneumoniae: implications for therapy.
Over the past 2 decades, antimicrobial resistance among Streptococcus pneumoniae, the most common cause of community-acquired pneumonia (CAP), has escalated dramatically worldwide. In the late 1970s, strains of pneumococci displaying resistance to penicillin were described in South Africa and Spain. By the early 1990s, penicillin-resistant clones of S. pneumoniae spread rapidly across Europe and globally. ⋯ Given these confounding factors, determining the impact of antimicrobial resistance on clinical outcomes is difficult, if not impossible. Prospective, randomized trials designed to assess the clinical significance of antimicrobial resistance among pneumococci are lacking, and for logistical reasons, will never be done. Does in vitro resistance translate into clinical failures? Should changing resistance patterns modify our choice of therapy for CAP or for suspected pneumococcal pneumonia? This review discusses several facets, including mechanisms of antimicrobial resistance among specific antibiotic classes, epidemiology and spread of antimicrobial resistance determinants regionally and worldwide, risk factors for acquisition and dissemination of resistance, the impact of key international clones displaying MDR, the clinical impact of antimicrobial resistance, and strategies to limit or curtail antimicrobial resistance among this key respiratory tract pathogen.
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Semin Respir Crit Care Med · Aug 2005
ReviewProstacyclin therapy for pulmonary arterial hypertension: new directions.
Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction and smooth muscle cell proliferation of the pulmonary arterioles, as well as in situ thrombosis of the small pulmonary arteries. Prostacyclin is involved in PAH vascular remodeling. ⋯ Treatment of PAH by inhibiting multiple pathways concurrently may produce additive benefit. Because prostacyclin therapy is not curative and does not normalize pulmonary hemodynamics in the majority of cases, combining a prostacyclin with other PAH agents may be a promising approach.
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Semin Respir Crit Care Med · Aug 2005
ReviewGenetics of pulmonary arterial hypertension: current and future implications.
Idiopathic pulmonary arterial hypertension (formerly primary pulmonary hypertension) can affect more than one member of the same family. In the past 25 years scientists have exposed the inheritance pattern and a major element of the molecular basis for inherited pulmonary arterial hypertension. Familial pulmonary arterial hypertension is inherited as an autosomal dominant trait with incomplete penetrance (i.e., several individuals inherit a predisposition to the disease, but never express it). ⋯ These mutations are present in at least half of familial cases of pulmonary arterial hypertension and 10 to 25% of idiopathic pulmonary arterial hypertension patients. Mutations in the gene that codes for activin receptor-like kinase (ALK 1), another transforming growth factor beta (TGF-beta) cell surface receptor, appear responsible for the rare occurrence of pulmonary arterial hypertension in patients with hereditary hemorrhagic telangiectasia. These discoveries coupled with other basic investigations offer opportunities for advances in the management of pulmonary arterial hypertension.
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Chronic obstructive pulmonary disease (COPD) is characterized and defined by limitation of expiratory airflow. This can result from several types of anatomical lesions, including loss of lung elastic recoil and fibrosis and narrowing of small airways. Inflammation, edema, and secretions also contribute variably to airflow limitation. ⋯ COPD is not only a disease of the lungs but is also a systemic inflammatory disorder. Muscular weakness, increased risk for atherosclerotic vascular disease, depression, osteoporosis, and abnormalities in fluids and electrolyte balance may all be consequences of COPD. Advances in understanding the pathogenesis of COPD have the potential for identifying new therapeutic targets that could alter the natural history of this devastating disorder.
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Pulmonary rehabilitation has been well established and increasingly recommended in disease management plans for patients with chronic obstructive pulmonary disease. Key elements include a multidisciplinary approach to care, focus on the individual patient, and attention to emotional and social as well as physical aspects of health. Appropriate candidates are symptomatic patients with chronic lung disease who are aware of their disability and motivated to participate actively in their own health care. ⋯ Program components include a careful patient evaluation, education, instruction in respiratory and chest physiotherapy techniques, exercise training, and psychosocial support. Benefits demonstrated in a growing body of evidence include improvement in symptoms, exercise tolerance, and quality of life and reduction in utilization of health care resources. Pulmonary rehabilitation has also been included as an adjunct to surgical programs such as lung transplantation and lung volume reduction surgery.