149 research outputs found
Coexistent Pseudogout and Mycobacterium avium-intracellulare
Pseudogout is a crystal-induced arthropathy characterized by the deposition of calcium pyrophosphate dihydrate (CPPD) crystals in synovial fluid, menisci, or articular cartilage. Although not very common, this entity can be seen in patients with chronic kidney disease (CKD). Septic arthritis due to Mycobacterium avium-intracellulare (MAI) is a rare entity that can affect immunocompromised patients such as those with acquired immunodeficiency syndrome (AIDS) or those who are on immunosuppressive drugs. Here, we describe a 51-year-old female who presented with fever, right knee pain, swelling, warmth, and decreased range of motion for several days. The initial assessment was consistent with pseudogout, with negative bacterial and fungal cultures. However, due to high white blood cell (WBC) count in the synovial fluid analysis, she was empirically started on intravenous (IV) vancomycin and piperacillin-tazobactam and discharged on IV vancomycin and cefepime, while acid-fast bacilli (AFB) culture was still in process. Seventeen days later, AFB culture grew Mycobacterium avium-intracellulare (MAI), and she was readmitted for relevant management. This case illustrates that septic arthritis due to MAI should be considered in the differential diagnosis of septic arthritis in immunocompromised patients
Acceptance and potential impact of the ewall platform for health monitoring and promotion in persons with a chronic disease or age-related impairment
Pervasive health technologies can increase the effectiveness of personal health monitoring and training, but more user studies are necessary to understand the interest for these technologies, and how they should be designed and implemented. In the present study, we evaluated eWALL, a user-centered pervasive health technology consisting of a platform that monitors users’ physical and cognitive behavior, providing feedback and motivation via an easy-to-use, touch-based user interface. The eWALL was placed for one month in the home of 48 subjects with a chronic condition (chronic obstructive pulmonary disease—COPD or mild cognitive impairment—MCI) or with an age-related impairment. User acceptance, platform use, and potential clinical effects were evaluated using surveys, data logs, and clinical scales. Although some features of the platform need to be improved before reaching technical maturity and making a difference in patients’ lives, the real-life evaluation of eWALL has shown how some features may influence patients’ intention to use this promising technology. Furthermore, this study made it clear how the free use of different health apps is modulated by the real needs of the patient and by their usefulness in the context of the patient’s clinical status
A Model for the Development of the Rhizobial and Arbuscular Mycorrhizal Symbioses in Legumes and Its Use to Understand the Roles of Ethylene in the Establishment of these two Symbioses
We propose a model depicting the development of nodulation and arbuscular mycorrhizae. Both processes are dissected into many steps, using Pisum sativum L. nodulation mutants as a guideline. For nodulation, we distinguish two main developmental programs, one epidermal and one cortical. Whereas Nod factors alone affect the cortical program, bacteria are required to trigger the epidermal events. We propose that the two programs of the rhizobial symbiosis evolved separately and that, over time, they came to function together. The distinction between these two programs does not exist for arbuscular mycorrhizae development despite events occurring in both root tissues. Mutations that affect both symbioses are restricted to the epidermal program. We propose here sites of action and potential roles for ethylene during the formation of the two symbioses with a specific hypothesis for nodule organogenesis. Assuming the epidermis does not make ethylene, the microsymbionts probably first encounter a regulatory level of ethylene at the epidermis–outermost cortical cell layer interface. Depending on the hormone concentrations there, infection will either progress or be blocked. In the former case, ethylene affects the cortex cytoskeleton, allowing reorganization that facilitates infection; in the latter case, ethylene acts on several enzymes that interfere with infection thread growth, causing it to abort. Throughout this review, the difficulty of generalizing the roles of ethylene is emphasized and numerous examples are given to demonstrate the diversity that exists in plants
Abrupt Ice Age Shifts in Southern Westerlies and Antarctic Climate Forced from the North
The Southern Hemisphere (SH) mid-latitude westerly winds play a central role in the global climate system via Southern Ocean upwelling, carbon exchange with the deep ocean, Agulhas Leakage, and Antarctic ice sheet stability. Meridional shifts in the SH westerlies have been hypothesized in response to abrupt North Atlantic Dansgaard-Oeschger (DO) climatic events of the last ice age, in parallel with the well-documented shifts of the intertropical convergence zone. Shifting moisture pathways to West Antarctica are consistent with this view, but may represent a Pacific teleconnection pattern. The full SH atmospheric-circulation response to the DO cycle, as well as its impact on Antarctic temperature, have so far remained unclear. Here we use five volcanically-synchronized ice cores to show that the Antarctic temperature response to the DO cycle can be understood as the superposition of two modes: a spatially homogeneous oceanic “bipolar seesaw” mode that lags Northern Hemisphere (NH) climate by about 200 years, and a spatially heterogeneous atmospheric mode that is synchronous with NH abrupt events. Temperature anomalies of the atmospheric mode are similar to those associated with present-day Southern Annular Mode (SAM) variability, rather than the Pacific South America (PSA) pattern. Moreover, deuterium excess records suggest a zonally coherent migration of the SH westerlies over all ocean basins in phase with NH climate. Our work provides a simple conceptual framework for understanding the circum-Antarctic temperature response to abrupt NH climate change. We provide observational evidence for abrupt shifts in the SH westerlies, with ramifications for global ocean circulation and atmospheric CO₂. These coupled changes highlight the necessity of a global, rather than a purely North Atlantic, perspective on the DO cycle
Southern Ocean deep convection as a driver of Antarctic warming events
Simulations with a free-running coupled climate model show that heat release associated with Southern Ocean deep convection variability can drive centennial-scale Antarctic temperature variations of up to 2.0 °C. The mechanism involves three steps: Preconditioning: heat accumulates at depth in the Southern Ocean; Convection onset: wind and/or sea-ice changes tip the buoyantly unstable system into the convective state; Antarctic warming: fast sea-ice–albedo feedbacks (on annual–decadal timescales) and slow Southern Ocean frontal and sea-surface temperature adjustments to convective heat release (on multidecadal–century timescales) drive an increase in atmospheric heat and moisture transport toward Antarctica. We discuss the potential of this mechanism to help drive and amplify climate variability as observed in Antarctic ice-core records
Contribution of NFP LysM Domains to the Recognition of Nod Factors during the Medicago truncatula/Sinorhizobium meliloti Symbiosis
The root nodule nitrogen fixing symbiosis between legume plants and soil bacteria called rhizobia is of great agronomical and ecological interest since it provides the plant with fixed atmospheric nitrogen. The establishment of this symbiosis is mediated by the recognition by the host plant of lipo-chitooligosaccharides called Nod Factors (NFs), produced by the rhizobia. This recognition is highly specific, as precise NF structures are required depending on the host plant. Here, we study the importance of different LysM domains of a LysM-Receptor Like Kinase (LysM-RLK) from Medicago truncatula called Nod factor perception (NFP) in the recognition of different substitutions of NFs produced by its symbiont Sinorhizobium meliloti. These substitutions are a sulphate group at the reducing end, which is essential for host specificity, and a specific acyl chain at the non-reducing end, that is critical for the infection process. The NFP extracellular domain (ECD) contains 3 LysM domains that are predicted to bind NFs. By swapping the whole ECD or individual LysM domains of NFP for those of its orthologous gene from pea, SYM10 (a legume plant that interacts with another strain of rhizobium producing NFs with different substitutions), we showed that NFP is not directly responsible for specific recognition of the sulphate substitution of S. meliloti NFs, but probably interacts with the acyl substitution. Moreover, we have demonstrated the importance of the NFP LysM2 domain for rhizobial infection and we have pinpointed the importance of a single leucine residue of LysM2 in that step of the symbiosis. Together, our data put into new perspective the recognition of NFs in the different steps of symbiosis in M. truncatula, emphasising the probable existence of a missing component for early NF recognition and reinforcing the important role of NFP for NF recognition during rhizobial infection
Advances, gaps and way forward in provision of climate services over the Greater Horn of Africa
The Greater Horn of Africa is prone to extreme climatic conditions, thus, making climate services increasingly important in supporting decision-making processes across a range of climate sensitive sectors. This study aims to provide a comprehensive review of the recent advances, gaps and challenges in the provision of climate services over the region, for each of the components of the Global Framework for Climate Services. The study explores various milestones that have been achieved toward climate service delivery. The achievements include improvement of station network coverage, and enhancing the capacity of member states to utilize various tools in data analysis and generate routine climate products. The advancement in science, and availability of High-Performance Computing has made it possible for forecast information to be provided from nowcasting to seasonal timescales. Moreover, operationalizing of the objective forecasting method for monthly and seasonal forecasts has made it possible to translate tercile forecasts for applications models. Additionally, innovative approaches to user engagement through co-production, communication channels, user-friendly interfaces, and dissemination of climate information have also been developed. Despite the significant progress that has been made in the provision of climate services, there are still many challenges and gaps that need to be overcome in order to ensure that these services are effectively meeting the needs of users. The research of the science underpinning climate variability, capacity building and stakeholder engagement, as well as improved data management and quality control processes are some of the gaps that exist over the region. Additionally, communication and dissemination of climate information, including timely warnings and risk communication, require improvement to reach diverse user groups effectively. Addressing these challenges will require strengthened partnerships, increased investment in capacity building, enhanced collaboration between the climate information producers and stakeholders, and the development of user-friendly climate products. Bridging these gaps will foster greater resilience to climate-related hazards and disasters in the Greater Horn of Africa and support sustainable development in the region
Planktivory in non-indigenous fish and implications for trophic interactions in a Mediterranean shallow lake
Similar to other Mediterranean lakes, Lake Vela displays a marked dominance of alien species, but the impact of such an assemblage on the lower trophic levels of shallow eutrophic lakes has been overlooked. In this study, zooplanktivory in the omnivorous fish assemblage of Lake Vela was examined from April to October 2003 (and also in January 2004). During this period, ichthyocenosis was characterized by abundance of juvenile fish, which strongly depended on zooplankton. Adult mosquitofish (Gambusia holbrooki) and pumpkinseed (Lepomis gibbosus) foraged on the same zooplanktonic prey than juveniles, although planktivory was less important in larger fish. Using multivariate analysis, it was possible to attribute most of the variability in planktivory to resource availability, as both fish foraged on the most abundant prey in each month. Albeit this opportunistic behaviour, mosquitofish was found to be positively selective towards small-sized littoral cladocerans, while pumpkinseed displayed positive selection towards Alona and Daphnia. In the absence of more efficient planktivores, pumpkinseed is now the main planktivore in Lake Vela and the main predator of Daphnia. However, due to low densities of Daphnia during most of the study period, Daphnia was virtually absent from the diet of pumpkinseed from June to October, a period during which this benthi–planktivore foraged chiefly on less-rewarding planktonic prey (small-sized cladocerans and cyclopoid copepods). Mosquitofish was an important planktivore in littoral and structured habitats. Flexible foraging behaviour partly explains the success of these two species in Lake Vela.Acknowledgements are due to José Vingada (University of Minho, Portugal) for supplying the fishing gear apparatuses and for providing help during fieldwork. We are also thankful to Francisca F. Gouveia for her laborious collaboration in the measurement and dissection of the fish. Bruno B. Castro was supported by a PhD grant (ref.SFRH/BD/6417/2001) from Fundação para a Ciência e a Tecnologia (Portugal). Bruno B. Castro is presently hired under the programme Ciência 2008 (FCT, Portugal), co-funded by the Human Potential Operational Programme (National Strategic Reference Framework 2007–2013) and European Social Fund (EU). We also thank two anonymous referees for their contribution in the improvement of the manuscript.publishe
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