Cystic fibrosis (CF) is an autosomal recessive genetic disorder resulting from genetic defects in the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. CFTR dysfunction in patients with CF leads to a number of pleiotropic manifestations with the prime pathology being mucus plugging in the airways and paranasal sinuses. Patients with CF are prone to polymicrobial infections and the airway microbiome in such patients changes continuously and evolves over time. The composition of the airway microbiome in CF patients is dependent on a number of factors including geographic variation, type of genetic mutation (e.g., ΔF508), antibiotic exposures, and chronic infection with certain pathogenic bacteria (e.g., Pseudomonas aeruginosa). Proteomic and genomic approaches to understanding the microbiome of patients with CF have provided new insights into the pathogenesis of this disease. High‐throughput pyrosequencing, Sanger sequencing, and phylogenetic microarray analysis have enabled the recognition of multiple lineages and clonal populations of a single bacterial species within the same patient. This provides a unique opportunity to explore novel therapeutic approaches to this disease (for instance, use of probiotics and environmental manipulation) and potentially translate them into bedside clinical interventions.
Part of the book: Progress in Understanding Cystic Fibrosis
Corticosteroids are adrenal hormones that play important physiologic roles including modulation of glucose metabolism, protein catabolism, alteration of calcium metabolism, regulation of bone turnover, suppression of immune system, and down-regulation of the inflammatory cascade. Because of their diverse effects, corticosteroids have been used therapeutically for treating a wide variety of auto-immune, rheumatologic, inflammatory, neoplastic and infectious diseases. In the field of pulmonology, corticosteroids have been used for the treatment of reactive airway diseases (such as asthma and allergic bronchopulmonary aspergillosis), chronic obstructive pulmonary disease, sarcoidosis, collagen vascular diseases (such as vasculitic disorders), eosinophilic pneumonitis, idiopathic interstitial pneumonias and infectious disorders (such as laryngotracheobronchitis). Different formulations of corticosteroids are commercially available including tablets, intravenous injections, intramuscular formulations and inhaled preparations. Long-term use of corticosteroids is often limited by their adverse effects, which include abnormal fat deposition, weight gain, diabetes mellitus, cataracts, glaucoma, osteoporosis, osteonecrosis, elevated risk of fractures, increased susceptibility to infections, proximal myopathy, depression, psychosis, adrenal atrophy with risk of Addisonian crisis, abdominal striae, acne vulgaris, delayed wound healing, easy bruising, electrolyte abnormalities and increased risk of peptic ulcer disease. As our understanding of corticosteroids advances, we may be able to identify individuals at higher risk of experiencing adverse effects.
Part of the book: Corticosteroids
Cohort studies are the analytical design of observational studies that are epidemiologically used to identify and quantify the relationship between exposure and outcome. Due to the longitudinal design, cohort studies have several advantages over other types of observational studies. The purpose of this chapter is to cover the various characteristics of prospective cohort studies. This chapter is divided into three main sections. In the first we introduce the concept and ranking of cohort studies, as well as the advantages and disadvantages. In the second we focus on the design of cohort studies, mainly its prospective aspect, and the distinguishing features from the retrospective type. The section also covers the essential characteristics of a cohort study design and its varied applications in medical research. In the third we go over examples of prospective studies in the medical field. For each, an overview of the study design is given, along with a random selection of study findings/impact, strengths and weaknesses.
Part of the book: Cohort Studies in Health Sciences