20 research outputs found
Huddle Up: Using Mediation to Help Settle the National Football League Labor Dispute
In a patient transferred from Togo to Cologne, Germany, Lassa fever was diagnosed 12 days post mortem. Sixty-two contacts in Cologne were categorised according to the level of exposure, and gradual infection control measures were applied. No clinical signs of Lassa virus infection or Lassa specific antibodies were observed in the 62 contacts. Thirty-three individuals had direct contact to blood, other body fluids or tissue of the patients. Notably, with standard precautions, no transmission occurred between the index patient and healthcare workers. However, one secondary infection occurred in an undertaker exposed to the corpse in Rhineland-Palatinate, who was treated on the isolation unit at the University Hospital of Frankfurt. After German authorities raised an alert regarding the imported Lassa fever case, an American healthcare worker who had cared for the index patient in Togo, and who presented with diarrhoea, vomiting and fever, was placed in isolation and medevacked to the United States. The event and the transmission of Lassa virus infection outside of Africa underlines the need for early diagnosis and use of adequate personal protection equipment (PPE), when highly contagious infections cannot be excluded. It also demonstrates that larger outbreaks can be prevented by infection control measures, including standard PPE
Detection of a genetic footprint of the sofosbuvir resistance-associated substitution S282T after HCV treatment failure
Background: The major resistance-associated substitution for sofosbuvir (S282T) in HCV NS5B causes severe viral fitness costs and rapidly reverts back to prototype in the absence of selection pressure. Accordingly, resistance against sofosbuvir is rarely detected even in patients after treatment failure. Case presentation: We report a case of a GT3a infected patient with viral breakthrough under SOF/DCV therapy. At the time of breakthrough the RAS S282T was predominant in NS5B and then rapidly disappeared during follow-up by week 12 after treatment. Interestingly, despite only serine was encoded in position 282 during follow-up, two distinct genetic pathways for reversion were detectable. In 31% of the quasispecies the original codon for serine was present whereas in the majority of the quasispecies an alternative codon was selected. This alternative codon usage was unique for all GT3a isolates from the HCV database and remained detectable as a genetic footprint for prior resistance selection at the RNA level for at least 6 months. Conclusions: Comparative analyses of viral sequences at the codon level before and after DAA treatment may help to elucidate the patient's history of resistance selection, which is particularly valuable for highly unfit substitutions that are detectable only for a short period of time. If such codon changes increase the risk of re-selection of resistance upon a second exposure to SOF remains to be addressed
Anal chromoendoscopy using gastroenterological videoendoscopes: A new method to perform high resolution anoscopy for diagnosing intraepithelial neoplasia and anal carcinoma in HIV-infected patients
Introduction Anal carcinoma represents an increasing problem in HIV-infected patients. Anal intraepithelial neoplasia (AIN), the precursor lesion, is currently diagnosed by high-resolution anoscopy (HRA) using optical magnification derived from gynecological colposcopy. This prospective study evaluates anal chromoendoscopy (ACE) using standard gastroenterological video-endoscopes in diagnosing AIN. Methods After clinical examination, proctoscopy and surface staining with acetic acid followed by Lugol's solution, ACE was performed with a mucosectomy cap on the tip of the endoscope. Biopsy specimens were collected from areas with a pathological staining pattern and from areas with normal appearance; combined results were considered as reference. Results Two hundred eleven HIV-positive patients seen between 2007 and 2013 were evaluated. Of these, 95.7 % were males, and the median age was 45 years. In 86.7 %, the mode of HIV transmission was sex among males. Combination antiretroviral treatment was applied in 75.8 %. The sensitivity of ACE in diagnosing AIN was 0.85, the specificity was 0.55, the positive predictive value was 0.50, and the negative predictive value (NPV) was 0.87. Diagnostic performance increased in individuals with high-grade lesions (NPV: 0.99) and in the second study period from 2011 to 2013. Side effects were rare and of minor clinical relevance. Conclusions Anal chromoendoscopy is safe and effective in diagnosing AIN in a population of HIV-infected patients. It is particularly useful for the exclusion of high-grade lesions that have the strongest risk of progression to anal carcinoma. Therefore, ACE may become a valuable new tool to manage AIN and to prevent anal malignancy in HIV-positive patients
The G Protein-Coupled Bile Acid Receptor TGR5 (Gpbar1) Modulates Endothelin-1 Signaling in Liver
TGR5 (Gpbar1) is a G protein-coupled receptor responsive to bile acids (BAs), which is expressed in different non-parenchymal cells of the liver, including biliary epithelial cells, liver-resident macrophages, sinusoidal endothelial cells (LSECs), and activated hepatic stellate cells (HSCs). Mice with targeted deletion of TGR5 are more susceptible towards cholestatic liver injury induced by cholic acid-feeding and bile duct ligation, resulting in a reduced proliferative response and increased liver injury. Conjugated lithocholic acid (LCA) represents the most potent TGR5 BA ligand and LCA-feeding has been used as a model to rapidly induce severe cholestatic liver injury in mice. Thus, TGR5 knockout (KO) mice and wildtype (WT) littermates were fed a diet supplemented with 1% LCA for 84 h. Liver injury and gene expression changes induced by the LCA diet revealed an enrichment of pathways associated with inflammation, proliferation, and matrix remodeling. Knockout of TGR5 in mice caused upregulation of endothelin-1 (ET-1) expression in the livers. Analysis of TGR5-dependent ET-1 signaling in isolated LSECs and HSCs demonstrated that TGR5 activation reduces ET-1 expression and secretion from LSECs and triggers internalization of the ET-1 receptor in HSCs, dampening ET-1 responsiveness. Thus, we identified two independent mechanisms by which TGR5 inhibits ET-1 signaling and modulates portal pressure
IFN-gamma licenses CD11b(+) cells to induce progression of systemic lupus erythematosus
Autoantibodies are a hallmark of autoimmune diseases, such as rheumatoid arthritis, autoimmune hepatitis, and systemic lupus erythematosus (SLE). High titers of anti-nuclear antibodies are used as surrogate marker for SLE, however their contribution to pathogenesis remains unclear. Using murine model of SLE and human samples, we studied the effect of immune stimulation on relapsing of SLE. Although autoantibodies bound to target cells in vivo, only additional activation of CD8(+) T cells converted this silent autoimmunity into overt disease. In mice as well as in humans CU8(+) T cells derived IFN-gamma enhanced expression of Fc-receptors on CD11b(+) cells. High expression of Fc-receptors allowed CD11b(+) cells to bind to antibody covered target cells and to destroy them in vivo. We found that autoantibodies induce clinically relevant disease when adaptive immunity, specific for disease non-related antigen, is activated. (C) 2015 Elsevier Ltd. All rights reserved
Model-guided identification of a therapeutic strategy to reduce hyperammonemia in liver diseases
Background & Aims: Recently, spatial-temporal/metabolic mathematical models have been established that allow the simulation of metabolic processes in tissues. We applied these models to decipher ammonia detoxification mechanisms in the liver. Methods: An integrated metabolic-spatial-temporal model was used to generate hypotheses of ammonia metabolism. Predicted mechanisms were validated using time-resolved analyses of nitrogen metabolism, activity analyses, immunostaining and gene expression after induction of liver damage in mice. Moreover, blood from the portal vein, liver vein and mixed venous blood was analyzed in a time dependent manner. Results: Modeling revealed an underestimation of ammonia consumption after liver damage when only the currently established mechanisms of ammonia detoxification were simulated. By iterative cycles of modeling and experiments, the reductive amidation of alpha-ketoglutarate (alpha-KG) via glutamate dehydrogenase (GDH) was identified as the lacking component. GDH is released from damaged hepatocytes into the blood where it consumes ammonia to generate glutamate, thereby providing systemic protection against hyperammonemia. This mechanism was exploited therapeutically in a mouse model of hyperammonemia by injecting GDH together with optimized doses of cofactors. Intravenous injection of GDH (720 U/kg), alpha-KG (280 mg/kg) and NADPH (180 mg/kg) reduced the elevated blood ammonia concentrations (>200 mu M) to levels close to normal within only 15 min. Conclusion: If successfully translated to patients the GDH-based therapy might provide a less aggressive therapeutic alternative for patients with severe hyperammonemia. (C) 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved