HIV-1 Vpr N-terminal tagging affects alternative splicing of the viral genome

To facilitate studies on Vpr function in replicating HIV-1, we aimed to tag the protein in an infectious virus. First we showed that N-, but not C-terminal HA/FLAG tagging of Vpr protein preserves Vpr cytopathicity. Cloning the tags into proviral DNA however ablated viral production and replication. By construction of additional viral variants we could show this defect was not protein-but RNA-dependent and sequence specific, and characterized by oversplicing of the genomic RNA. Simulation of genomic RNA folding suggested that introduction of the tag sequence induced an alternative folding structure in a region enriched in splice sites and splicing regulatory sequences. In silico predictions identified the HA/His(6)-Vpr tagging in HIV-1 to affect mRNA folding less than HA/FLAG-Vpr tagging. In vitro infectivity and mRNA splice pattern improved but did not reach wild-type values. Thus, sequence-specific insertions may interfere with mRNA splicing, possibly due to altered RNA folding. Our results point to the complexity of viral RNA genome sequence interactions. This should be taken into consideration when designing viral manipulation strategies, for both research as for biological interventions

African Trypanosomiasis-associated anemia : the contribution of the interplay between parasites and the mononuclear phagocyte system

African trypanosomosis (AT) is a chronically debilitating parasitic disease of medical and economic importance for the development of sub-Saharan Africa. The trypanosomes that cause this disease are extracellular protozoan parasites that have developed efficient immune escape mechanisms to manipulate the entire host immune response to allow parasite survival and transmission. During the early stage of infection, a profound pro-inflammatory type 1 activation of the mononuclear phagocyte system (MPS), involving classically activated macrophages (i.e., M1), is required for initial parasite control. Yet, the persistence of this M1-type MPS activation in trypanosusceptible animals causes immunopathology with anemia as the most prominent pathological feature. By contrast, in trypanotolerant animals, there is an induction of IL-10 that promotes the induction of alternatively activated macrophages (M2) and collectively dampens tissue damage. A comparative gene expression analysis between M1 and M2 cells identified galectin-3 (Gal-3) and macrophage migration inhibitory factor (MIF) as novel M1-promoting factors, possibly acting synergistically and in concert with TNF-alpha during anemia development. While Gal-3 enhances erythrophagocytosis, MIF promotes both myeloid cell recruitment and iron retention within the MPS, thereby depriving iron for erythropoiesis. Hence, the enhanced erythrophagocytosis and suppressed erythropoiesis lead to anemia. Moreover, a thorough investigation using MIF-deficient mice revealed that the underlying mechanisms in AT-associated anemia development in trypanosusceptible and tolerant animals are quite distinct. In trypanosusceptible animals, anemia resembles anemia of inflammation, while in trypanotolerant animals' hemodilution, mainly caused by hepatosplenomegaly, is an additional factor contributing to anemia. In this review, we give an overview of how trypanosome-and host-derived factors can contribute to trypanosomosis-associated anemia development with a focus on the MPS system. Finally, we will discuss potential intervention strategies to alleviate AT-associated anemia that might also have therapeutic potential

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Methemoglobinemia : a rare side effect of a healthy diet

Methemoglobinemia: a rare side effect of a healthy diet P Naessens, T Van Der Heggen, A D'Hooghe, K Sauer. AZ Sint-Jan Background An 11-month-old girl, without relevant medical history, presented at the emergency department with central cyanosis and an extremely pale skin, noticed by her parents when she woke up from an afternoon nap. She was alert but irritable, there was no shortness of breath. Her oxygen saturation was 80-85% while breathing ambient air and did not respond to high flow oxygen. Chest X-ray was normal. Venous blood gas analysis showed a normal pO2, but revealed methemoglobin (MetHb) levels of 44%. Before sleeping, the girl had lunch with home grown turnips and broad beans. Methods A literature-search was done in PubMed with MeSH-terms ‘cyanosis’, ‘methemoglobinemia’ and ‘child’. Results Methemoglobinemia is characterized by increased quantities of hemoglobin containing iron in the oxidized ferric form (Fe3+) instead of the usual ferrous (Fe2+) form. It is an uncommon blood disorder, resulting in a ‘functional anemia’ with tissue hypoxia. Patients present with a varying degree of cyanosis, proportional to their MetHb level. Symptoms are usually noticed starting from a 15% fraction (normal MetHb fraction is 1%). Levels higher than 70% can be fatal. The etiology is either congenital or acquired and in most cases due to exposure to oxidizing drugs or toxins, by ingestion or skin contact. In our patient, the presumed causative agent is a high amount of nitrates, a molecule found in well water and some foods, especially in green leafy vegetables and root vegetables. Hereditary methemoglobinemia is rare but should be considered. The diagnosis is confirmed by direct measurement of MetHb, but can be suspected from a normal pO2 concentration on a blood gas, despite cyanosis and a low oxygen saturation. If identified, it is important to remove or discontinue the causative agent. Supplemental oxygen should be administered. Treatment with methylene blue is advised if MetHb level > 20%. In critically ill patients, or if MetHb level > 70%, an exchange transfusion or hemodialysis should be considered immediately. Conclusion Always suspect methemoglobinemia in children with central cyanosis without respiratory distress or cardiac disorder, not responding to oxygen administration. Low oxygen saturation with normal pO2 on blood gas analysis provides the clue to diagnosis. Usually methemoglobinemia is caused by exposure to certain drugs or toxins that can be found even in vegetables. Methylene blue is the treatment of choice

Carebook: Assisting elderly people by social networking

In Belgium (and many other European countries), the avarage age of individuals is increasing significantly. Many governmental as well as commercial initiatives aim at supporting elderly people in daily tasks. Examples are cooking services, cleaning services and health related services (such as washing, pedicure . . . ). However, society can no longer sustain the huge costs of these services. Moreover, some tasks can easily be performed by relatives (i.e. people in the social network around a person that needs assistance). For instance, a neighbour can cook frequently or a daughter can clean the house. Although relatives can reduce the increasing work load and costs, many elderly people are reluctant to rely on their social network for two main reasons. First, unfair task allocations may put a burden on certain relatives. Second, the execution of certain tasks (such as meal services) must be guaranteed daily. Many relatives may in fact be willing to other health care support to patients although they do not want to give a commitment to other it daily and for a long period. A fair digital platform for building and maintaining a social network around elderly persons may overcome these barriers. Sites, such as LinkedIn[4], FaceBook[3] and Twitter[7], show that maintaining social networks is nowadays an important part of people's activities in the virtual world of the internet. Contacts with friends and relatives on social network sites are seen as easier to maintain, but equally relevant, as real-life contacts. Our platform is inspired by the ease-of-use and potential of social network sites. Clearly, the requirements for our platform differ greatly from those of social network sites. For instance, our platform requires the support of more advanced services than only generic communication services, and we need to devote even more attention to advanced security and privacy issues[5][6]. These requirements are driven by the high sensitivity of data that must often be released to/by caregivers.status: publishe

Beyond us and them: A mixed method approach supporting a virtual scientific interdisciplinary organization

This paper studies the need within a geographically dispersed, virtual, interdisciplinary institute, the IBBT, how the collaboration within this organization could be enhanced by looking into the current collaboration practices. The IBBT performs research and supports ICT innovation in the region of Flanders and acts as a central institute between different research groups located at five different cities. Therefore a combination of four methods in different phases of data collection was applied to create a mixed method participatory User Centered Design approach with specific attention to the appropriation of current social tools. This research is targeted at understanding the different research groups of the IBBT and finally supplying the organization with suggestions and solutions to improve the collaboration between the different research partners. Through our approach we get an overview of the current practices and CSCW-tools used within the research groups themselves and in the collaboration with other IBBT research groups and external partners. They lead to the formulation of a set of needs and requirements to how the groups see their future activities facilitated by a set of tools. The mixed use of methods is evaluated at the end regarding their successful complementary use in pursuit of these requirements.status: publishe