Tulane University

About: Tulane University is a education organization based out in New Orleans, Louisiana, United States. It is known for research contribution in the topics: Population & Blood pressure. The organization has 24478 authors who have published 47205 publications receiving 1944993 citations. The organization is also known as: University of Louisiana.

House-to-house human movement drives dengue virus transmission

Abstract: Dengue is a mosquito-borne disease of growing global health importance. Prevention efforts focus on mosquito control, with limited success. New insights into the spatiotemporal drivers of dengue dynamics are needed to design improved disease-prevention strategies. Given the restricted range of movement of the primary mosquito vector, Aedes aegypti, local human movements may be an important driver of dengue virus (DENV) amplification and spread. Using contact-site cluster investigations in a case-control design, we demonstrate that, at an individual level, risk for human infection is defined by visits to places where contact with infected mosquitoes is likely, independent of distance from the home. Our data indicate that house-to-house human movements underlie spatial patterns of DENV incidence, causing marked heterogeneity in transmission rates. At a collective level, transmission appears to be shaped by social connections because routine movements among the same places, such as the homes of family and friends, are often similar for the infected individual and their contacts. Thus, routine, house-to-house human movements do play a key role in spread of this vector-borne pathogen at fine spatial scales. This finding has important implications for dengue prevention, challenging the appropriateness of current approaches to vector control. We argue that reexamination of existing paradigms regarding the spatiotemporal dynamics of DENV and other vector-borne pathogens, especially the importance of human movement, will lead to improvements in disease prevention.

The tail suspension test.

Abstract: The tail-suspension test is a mouse behavioral test useful in the screening of potential antidepressant drugs, and assessing of other manipulations that are expected to affect depression related behaviors. Mice are suspended by their tails with tape, in such a position that it cannot escape or hold on to nearby surfaces. During this test, typically six minutes in duration, the resulting escape oriented behaviors are quantified. The tail-suspension test is a valuable tool in drug discovery for high-throughput screening of prospective antidepressant compounds. Here, we describe the details required for implementation of this test with additional emphasis on potential problems that may occur and how to avoid them. We also offer a solution to the tail climbing behavior, a common problem that renders this test useless in some mouse strains, such as the widely used C57BL/6. Specifically, we prevent tail climbing behaviors by passing mouse tails through a small plastic cylinder prior to suspension. Finally, we detail how to manually score the behaviors that are manifested in this test.

The natriuretic peptide clearance receptor locally modulates the physiological effects of the natriuretic peptide system

Abstract: Natriuretic peptides (NPs), mainly produced in heart [atrial (ANP) and B-type (BNP)], brain (CNP), and kidney (urodilatin), decrease blood pressure and increase salt excretion. These functions are mediated by natriuretic peptide receptors A and B (NPRA and NPRB) having cytoplasmic guanylyl cyclase domains that are stimulated when the receptors bind ligand. A more abundantly expressed receptor (NPRC or C-type) has a short cytoplasmic domain without guanylyl cyclase activity. NPRC is thought to act as a clearance receptor, although it may have additional functions. To test how NPRC affects the cardiovascular and renal systems, we inactivated its gene (Npr3) in mice by homologous recombination. The half life of [125I]ANP in the circulation of homozygotes lacking NPRC is two-thirds longer than in the wild type, although plasma levels of ANP and BNP in heterozygotes and homozygotes are close to the wild type. Heterozygotes and homozygotes have a progressively reduced ability to concentrate urine, exhibit mild diuresis, and tend to be blood volume depleted. Blood pressure in the homozygotes is 8 mmHg (1 mmHg = 133 Pa) below normal. These results are consistent with the sole cardiovascular/renal function of NPRC being to clear natriuretic peptides, thereby modulating local effects of the natriuretic peptide system. Unexpectedly, Npr3 −/− homozygotes have skeletal deformities associated with a considerable increase in bone turnover. The phenotype is consistent with the bone function of NPRC being to clear locally synthesized CNP and modulate its effects. We conclude that NPRC modulates the availability of the natriuretic peptides at their target organs, thereby allowing the activity of the natriuretic peptide system to be tailored to specific local needs.

Integrating function and ecology in studies of adaptation: Investigations of locomotor capacity as a model system

Abstract: ▪ Abstract Understanding adaptation in morphological and physiological traits requires elucidation of how traits relate to whole-organism performance and how performance relates to fitness. A common assumption is that performance capacities are utilized by and important to organisms. For some systems, it is assumed that high levels of physical fitness, as indexed by measures of locomotor performance, lead to high fitness levels. Although biologists have appreciated this, little attention has been paid to quantifying how organisms use their performance capacities in nature. We argue that for the study of adaptation to proceed, greater integration of laboratory studies of performance and behavioral/ecological studies is needed, and we illustrate this approach by examining two questions. First, how does the environment affect locomotor function in nature? Second, what percentage of locomotor capacities do animals use in nature? A review of studies in several animal groups shows widespread effects of the envi...

Using Respondent-Driven Sampling Methodology for HIV Biological and Behavioral Surveillance in International Settings: A Systematic Review

Abstract: To determine operational and analytical characteristics of respondent-driven sampling (RDS) in international settings and to explore factors that may affect recruitment of most-at-risk populations using RDS, we reviewed HIV biological and behavioral surveillance studies that used this method outside of the United States. We identified 123 eligible studies, 59 from Europe, 40 from Asia and the Pacific, 14 from Latin America, seven from Africa and three from Oceania. Studies collectively recruited 32,298 participants between 2003 and 2007; 53% of studies were conducted among injecting drug users, which generally had faster recruitment compared with studies among sex workers. All but 13 studies reached > or = 90% of their intended sample size, and six studies failed to reach equilibrium for key variables. This review has shown that RDS is an effective technique, when designed and implemented appropriately, to sample most-at-risk populations for HIV biological and behavioral surveys.