72 research outputs found
Genomotyping of Coxiella burnetii Using Microarrays Reveals a Conserved Genomotype for Hard Tick Isolates
C. burnetii is a Gram-negative intracellular Y-proteobacteria that causes the zoonotic disease Q fever. Q fever can manifest as an acute or chronic illness. Different typing methods have been previously developed to classify C. burnetii isolates to explore its pathogenicity. Here, we report a comprehensive genomotyping method based on the presence or absence of genes using microarrays. The genomotyping method was then tested in 52 isolates obtained from different geographic areas, different hosts and patients with different clinical manifestations. The analysis revealed the presence of 10 genomotypes organized into 3 groups, with a topology congruent with that obtained through multi-spacer typing. We also found that only 4 genomotypes were specifically associated with acute Q fever, whereas all of the genomotypes could be associated to chronic human infection. Serendipitously, the genomotyping results revealed that all hard tick isolates, including the Nine Mile strain, belong to the same genomotype
Coxiella burnetii in Humans and Ticks in Rural Senegal
Q fever is a zoonotic disease known since 1937. The disease may be severe, causing pneumonia, hepatitis and endocarditis. Q fever agent has been described as a possible biological weapon. Animals—especially domestic cows, goats and sheep—are considered reservoirs for this infection. They are capable of sustaining the infection for long periods and excreting viable bacteria, infecting other animals and, occasionally, humans. Here we studied the distribution of Q fever in a poorly studied region, Senegal. We studied the agent of Q fever both in ticks parasitizing domestic animals and in humans (antibodies in serum, bacteria in feces, saliva and milk). We found from the studied regions the bacterium is highly prevalent in rural Senegal. Up to 37.6% of five different and most prevalent tick species may carry the bacterium. Humans living in such areas, as other mammals, may occasionally excrete Q fever agent through feces and milk
Major Role of Microbes in Carbon Fluxes during Austral Winter in the Southern Drake Passage
Carbon cycling in Southern Ocean is a major issue in climate change, hence the need to understand the role of biota in the regulation of carbon fixation and cycling. Southern Ocean is a heterogeneous system, characterized by a strong seasonality, due to long dark winter. Yet, currently little is known about biogeochemical dynamics during this season, particularly in the deeper part of the ocean. We studied bacterial communities and processes in summer and winter cruises in the southern Drake Passage. Here we show that in winter, when the primary production is greatly reduced, Bacteria and Archaea become the major producers of biogenic particles, at the expense of dissolved organic carbon drawdown. Heterotrophic production and chemoautotrophic CO2 fixation rates were substantial, also in deep water, and bacterial populations were controlled by protists and viruses. A dynamic food web is also consistent with the observed temporal and spatial variations in archaeal and bacterial communities that might exploit various niches. Thus, Southern Ocean microbial loop may substantially maintain a wintertime food web and system respiration at the expense of summer produced DOC as well as regenerate nutrients and iron. Our findings have important implications for Southern Ocean ecosystem functioning and carbon cycle and its manipulation by iron enrichment to achieve net sequestration of atmospheric CO2
Urban and Transport Scaling: Northern Mesopotamia in the Late Chalcolithic and Bronze Age
Scaling methods have been applied to study modern urban areas and how they create accelerated, feedback growth in some systems while efficient use in others. For ancient cities, results have shown that cities act as social reactors that lead to positive feedback growth in socioeconomic measures. In this paper, we assess the relationship between settlement area expressed through mound area from Late Chalcolithic and Bronze Age sites and mean hollow way widths, which are remains of roadways, from the Khabur Triangle in northern Mesopotamia. The intent is to demonstrate the type of scaling and relationship present between sites and hollow ways, where both feature types are relatively well preserved. For modern roadway systems, efficiency in growth relative to population growth suggests roads should show sublinear scaling in relation to site size. In fact, similar to modern systems, such sublinear scaling results are demonstrated for the Khabur Triangle using available data, suggesting ancient efficiency in intensive transport growth relative to population levels. Comparable results are also achieved in other ancient Near East regions. Furthermore, results suggest that there could be a general pattern relevant for some small sites (0–2 ha) and those that have fewer hollow ways, where β, a measure of scaling, is on average low (≈ < 0.2). On the other hand, a second type of result for sites with many hollow ways (11 or more) and that are often larger suggests that β is greater (0.23–0.72), but still sublinear. This result could reflect the scale in which larger settlements acted as greater social attractors or had more intensive economic activity relative to smaller sites. The provided models also allow estimations of past roadway widths in regions where hollow ways are missing
Functional outcome, revision rates and mortality after primary total hip replacement--a national comparison of nine prosthesis brands in England.
BACKGROUND: The number of prosthesis brands used for hip replacement has increased rapidly, but there is little evidence on their effectiveness. We compared patient-reported outcomes, revision rates, and mortality for the three most frequently used brands within each prosthesis type: cemented (Exeter V40 Contemporary, Exeter V40 Duration and Exeter V40 Elite Plus Ogee), cementless (Corail Pinnacle, Accolade Trident, and Taperloc Exceed), and hybrid (Exeter V40 Trilogy, Exeter V40 Trilogy, and CPT Trilogy). METHODS AND FINDINGS: We used three national databases of patients who had hip replacements between 2008 and 2011 in the English NHS to compare functional outcome (Oxford Hip Score (OHS) ranging from 0 (worst) to 48 (best)) in 43,524 patients at six months. We analysed revisions and mortality in 187,201 patients. We used multiple regression to adjust for pre-operative differences. Prosthesis type had an impact on post-operative OHS and revision rates (both p<0.001). Patients with hybrid prostheses had the best functional outcome (mean OHS 39.4, 95%CI 39.1 to 39.7) and those with cemented prostheses the worst (37.7, 37.3 to 38.1). Patients with cemented prostheses had the lowest reported 5-year revision rates (1.3%, 1.2% to 1.4%) and those with cementless prostheses the highest (2.2%, 2.1% to 2.4%). Differences in mortality according to prosthesis type were small and not significant (p = 0.06). Functional outcome varied according to brand among cemented (p = 0.05, with Exeter V40 Duration having the best) and cementless prostheses (p = 0.01, with Corail Pinnacle having the best). Revision rates varied according to brand among hybrids (p = 0.05, with Exeter V40 Trident having the lowest). CONCLUSIONS: Functional outcomes were better with cementless cups and revision rates were lower with cemented stems, which underlies the good overall performance of hybrids. The hybrid Exeter V40 Trident seemed to produce the best overall results. This brand should be considered as a benchmark in randomised trials
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