Acute exacerbations adversely affect patients with chronic obstructive pulmonary disease (COPD). Macrolide antibiotics benefit patients with a variety of inflammatory airway diseases.
We performed a ...randomized trial to determine whether azithromycin decreased the frequency of exacerbations in participants with COPD who had an increased risk of exacerbations but no hearing impairment, resting tachycardia, or apparent risk of prolongation of the corrected QT interval.
A total of 1577 subjects were screened; 1142 (72%) were randomly assigned to receive azithromycin, at a dose of 250 mg daily (570 participants), or placebo (572 participants) for 1 year in addition to their usual care. The rate of 1-year follow-up was 89% in the azithromycin group and 90% in the placebo group. The median time to the first exacerbation was 266 days (95% confidence interval CI, 227 to 313) among participants receiving azithromycin, as compared with 174 days (95% CI, 143 to 215) among participants receiving placebo (P<0.001). The frequency of exacerbations was 1.48 exacerbations per patient-year in the azithromycin group, as compared with 1.83 per patient-year in the placebo group (P=0.01), and the hazard ratio for having an acute exacerbation of COPD per patient-year in the azithromycin group was 0.73 (95% CI, 0.63 to 0.84; P<0.001). The scores on the St. George's Respiratory Questionnaire (on a scale of 0 to 100, with lower scores indicating better functioning) improved more in the azithromycin group than in the placebo group (a mean ±SD decrease of 2.8±12.8 vs. 0.6±11.4, P=0.004); the percentage of participants with more than the minimal clinically important difference of -4 units was 43% in the azithromycin group, as compared with 36% in the placebo group (P=0.03). Hearing decrements were more common in the azithromycin group than in the placebo group (25% vs. 20%, P=0.04).
Among selected subjects with COPD, azithromycin taken daily for 1 year, when added to usual treatment, decreased the frequency of exacerbations and improved quality of life but caused hearing decrements in a small percentage of subjects. Although this intervention could change microbial resistance patterns, the effect of this change is not known. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00325897.).
Astrocytes, the most abundant glial cells in the mammalian brain, are critical regulators of brain development and physiology through dynamic and often bidirectional interactions with neuronal ...synapses. Despite the clear importance of astrocytes for the establishment and maintenance of proper synaptic connectivity, our understanding of their role in brain function is still in its infancy. We propose that this is at least in part due to large gaps in our knowledge of the cell biology of astrocytes and the mechanisms they use to interact with synapses. In this review, we summarize some of the seminal findings that yield important insight into the cellular and molecular basis of astrocyte-neuron communication, focusing on the role of astrocytes in the development and remodeling of synapses. Furthermore, we pose some pressing questions that need to be addressed to advance our mechanistic understanding of the role of astrocytes in regulating synaptic development.
Allen and Eroglu review the current state of knowledge on the cell biology of astrocyte-synapse interactions and pose some pressing questions that need to be addressed to advance our understanding of the role of astrocytes in brain function.
City-regions reconsidered Scott, Allen J.
Environment and planning. A,
05/2019, Letnik:
51, Številka:
3
Journal Article
Recenzirano
I seek to provide an overview of the historical and geographical emergence of city-regions and to reflect on some of the debates that have arisen in regard to the theoretical status of these ...phenomena. I briefly describe the growth and spread of city-regions in the world since the mid-1950s and I consider how contemporary capitalism and globalization have fostered the development of this distinctive urban form. The internal organization of city-regions is then examined, with special reference to four generic outcomes: (1) aestheticized land-use intensification; (2) gentrification; (3) social polarization and informality; and (4) postsuburban landscapes. Issues of governance and policy are scrutinized and basic dilemmas of political coordination in city-regions are described. The argument ends with an evaluative review of certain critiques of the city-region idea in the current academic literature.
There has been a growing debate in recent decades about the range and substance of urban theory. The debate has been marked by many different claims about the nature of cities, including declarations ...that the urban is an incoherent concept, that urban society is nothing less than modern society as a whole, that the urban scale can no longer be separated from the global scale, and that urban theory hitherto has been deeply vitiated by its almost exclusive concentration on the cities of the global North. This article offers some points of clarification of claims like these. All cities can be understood in terms of a theoretical framework that combines two main processes, namely, the dynamics of agglomeration/polarization, and the unfolding of an associated nexus of locations, land uses and human interactions. This same framework can be used to identify many different varieties of cities, and to distinguish intrinsically urban phenomena from the rest of social reality. The discussion thus identifies the common dimensions of all cities without, on the one hand, exaggerating the scope of urban theory, or on the other hand, asserting that every individual city is an irreducible special case.
Astrocytes regulate multiple aspects of neuronal and synaptic function from development through to adulthood. Instead of addressing each function independently, this review provides a comprehensive ...overview of the different ways astrocytes modulate neuronal synaptic function throughout life, with a particular focus on recent findings in each area. It includes the emerging functions of astrocytes, such as a role in synapse formation, as well as more established roles, including the uptake and recycling of neurotransmitters. This broad approach covers the many ways astrocytes and neurons constantly interact to maintain the correct functioning of the brain. It is important to consider all of these diverse functions of astrocytes when investigating how astrocyte-neuron interactions regulate synaptic behavior to appreciate the complexity of these ongoing interactions.
Glia constitute roughly half of the cells of the central nervous system (CNS) but were long-considered to be static bystanders to its formation and function. Here we provide an overview of how the ...diverse and dynamic functions of glial cells orchestrate essentially all aspects of nervous system formation and function. Radial glia, astrocytes, oligodendrocyte progenitor cells, oligodendrocytes, and microglia each influence nervous system development, from neuronal birth, migration, axon specification, and growth through circuit assembly and synaptogenesis. As neural circuits mature, distinct glia fulfill key roles in synaptic communication, plasticity, homeostasis, and network-level activity through dynamic monitoring and alteration of CNS structure and function. Continued elucidation of glial cell biology, and the dynamic interactions of neurons and glia, will enrich our understanding of nervous system formation, health, and function.
On Hollywood Scott, Allen John
2018., 20180605, 2018, 2004, 2018-06-05, 20050101
eBook
Why is the U.S. motion picture industry concentrated in Hollywood and why does it remain there in the age of globalization? Allen Scott uses the tools of economic geography to explore these questions ...and to provide a number of highly original answers. The conceptual roots of his analysis go back to Alfred Marshall's theory of industrial districts and pick up on modern ideas about business clusters as sites of efficient and innovative production. On Hollywood builds on this work by adding major new empirical elements. By examining the history of motion-picture production from the early twentieth century to the present through this analytic lens, Scott is able to show why the industry (which was initially focused on New York) had shifted the majority of its production to Southern California by 1919. He also addresses in detail the bases of Hollywood's long-standing creative energies and competitive advantages. At the same time, the book explores the steady globalization of Hollywood's market reach as well as the cultural and political dilemmas posed by this phenomenon. On Hollywood will appeal not only to general readers with an interest in the motion-picture industry, but also to economic geographers, business professionals, regional development practitioners, and cultural theorists as well.
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