JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Increased neutrophil extracellular trap-mediated Staphylococcus aureus clearance through inhibition of nuclease activity by clindamycin and immunoglobulin.
J. Infect. Dis.
PUBLISHED: 02-12-2014
Show Abstract
Hide Abstract
The Gram-positive human pathogen Staphylococcus aureus causes a variety of human diseases such as skin infections, pneumonia, and endocarditis. The micrococcal nuclease Nuc1 is one of the major S. aureus virulence factors and allows the bacterium to avoid neutrophil extracellular trap (NET)-mediated killing. We found that addition of the protein synthesis inhibitor clindamycin to S. aureus LAC cultures decreased nuc1 transcription and subsequently blunted nuclease activity in a molecular beacon-based fluorescence assay. We also observed reduced NET degradation through Nuc1 inhibition translating into increased NET-mediated clearance. Similarly, pooled human immunoglobulin specifically inhibited nuclease activity in a concentration-dependent manner. Inhibition of nuclease activity by clindamycin and immunoglobulin enhanced S. aureus clearance and should be considered in the treatment of S. aureus infections.
Related JoVE Video
The IL-8 protease SpyCEP is detrimental for Group A Streptococcus host-cells interaction and biofilm formation.
Front Microbiol
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
SpyCEP-mediated chemokine degradation translates into more efficient spreading and increased severity of invasive Group A Streptococcus (GAS) infections, due to impaired neutrophil recruitment to the site of infection. SpyCEP is markedly up-regulated in invasive as compared to colonizing GAS isolates raising the question whether SpyCEP expression hinders bacterial attachment and thus colonization of the host. To address this question we used a molecular approach involving the use of homologous GAS strains either expressing or not SpyCEP or expressing an enzymatically inactive variant of SpyCEP. We found that expression of enzymatically functional SpyCEP lowered GAS adherence and invasion potential toward various epithelial and endothelial cells. SpyCEP also blunted biofilm formation capacity. Our data indicate that expression of SpyCEP decreases colonization and thus might be detrimental for the spreading of GAS.
Related JoVE Video
Early fluid resuscitation with hydroxyethyl starch 130/0.4 (6%) in severe burn injury: a randomized, controlled, double-blind clinical trial.
Crit Care
PUBLISHED: 07-11-2013
Show Abstract
Hide Abstract
There are limited data on the efficacy of early fluid resuscitation with third generation hydroxyethyl starch (HES 130) in burn injury. Adverse effects of HES on survival and organ function have been reported.
Related JoVE Video
Extracorporeal membrane oxygenation: beneficial strategy for lung transplant recipients.
J Extra Corpor Technol
PUBLISHED: 05-23-2013
Show Abstract
Hide Abstract
The role of extracorporeal membrane oxygenation (ECMO) as a therapeutic strategy has been very well documented for over a decade now with consistently positive remarks. The aim of the present study was analyzing the outcome of ECMO application in our lung transplant program, especially the feasibility and safety of our ECMO approach. Therefore, we retrospectively analyzed the data of 15 patients recipients requiring ECMO support. We analyzed clinical data, complications, and survival of the lung-transplanted population that needed ECMO support at our institution from 2006-2009. During that period, 19 applications of ECMO were done on 15 adult patients with the following indications: primary graft dysfunction (10 patients), "bridge to transplantation" (five), pulmonary hypertension (three), and severe acute respiratory distress syndrome (one). At 28 days, the overall survival was 93% (14 of 15 patients) and 12 of these patients (80%) survived at least 6 months. Complications included acute renal insufficiency with temporary need of renal replacement therapy (53%), bleeding (33%), critical illness polyneuropathy (66%), and reversible thrombocytopenia (73%). Based on the evaluation of the patients in this analysis, ECMO seems to be a safe therapeutic approach in lung transplant recipients with severe respiratory failure directly after transplantation.
Related JoVE Video
ICU, hospital and one year mortality of patients suffering from solid or haematological malignancies.
Swiss Med Wkly
PUBLISHED: 04-11-2013
Show Abstract
Hide Abstract
To examine the demographics, evolution and outcome of patients suffering from malignancies admitted to a medical intensive care unit.
Related JoVE Video
Coiled-coil irregularities of the M1 protein structure promote M1-fibrinogen interaction and influence group A Streptococcus host cell interactions and virulence.
J. Mol. Med.
PUBLISHED: 02-15-2013
Show Abstract
Hide Abstract
Group A Streptococcus (GAS) is a human pathogen causing a wide range of mild to severe and life-threatening diseases. The GAS M1 protein is a major virulence factor promoting GAS invasiveness and resistance to host innate immune clearance. M1 displays an irregular coiled-coil structure, including the B-repeats that bind fibrinogen. Previously, we found that B-repeat stabilisation generates an idealised version of M1 (M1) characterised by decreased fibrinogen binding in vitro. To extend these findings based on a soluble truncated version of M1, we now studied the importance of the B-repeat coiled-coil irregularities in full length M1 and M1 expressed in live GAS and tested whether the modulation of M1-fibrinogen interactions would open up novel therapeutic approaches. We found that altering either the M1 structure on the GAS cell surface or removing its target host protein fibrinogen blunted GAS virulence. GAS expressing M1 showed an impaired ability to adhere to and to invade human endothelial cells, was more readily killed by whole blood or neutrophils and most importantly was less virulent in a murine necrotising fasciitis model. M1-mediated virulence of wild-type GAS was strictly dependent on the presence and concentration of fibrinogen complementing our finding that M1-fibrinogen interactions are crucial for GAS virulence. Consistently blocking M1-fibrinogen interactions by fragment D reduced GAS virulence in vitro and in vivo. This supports our conclusion that M1-fibrinogen interactions are crucial for GAS virulence and that interference may open up novel complementary treatment options for GAS infections caused by the leading invasive GAS strain M1.
Related JoVE Video
The relationship between preoperative creatinine clearance and outcomes for patients undergoing liver transplantation: a retrospective observational study.
BMC Nephrol
PUBLISHED: 02-13-2013
Show Abstract
Hide Abstract
Renal failure with following continuous renal replacement therapy is a major clinical problem in liver transplant recipients, with reported incidences of 3% to 20%. Little is known about the significance of postoperative acute renal failure or acute-on-chronic renal failure to postoperative outcome in liver transplant recipients.
Related JoVE Video
Pretransplant dyslipidaemia determines outcome in lung transplant recipients.
Lipids Health Dis
PUBLISHED: 01-08-2013
Show Abstract
Hide Abstract
There is little knowledge about the effect of dyslipidaemia on the outcome after lung transplantation. Thus, the aim of this retrospective single centre study was to analyse the impact of the plasma lipid profile on mortality in lung transplant recipients. From January 2000 to December 2008 the charts of 172 consecutive lung transplantation recipients were analysed. At baseline and after one year lipid profiles were routinely collected. During the follow-up major cardiovascular events (MCE; beginning of dialysis, cerebrovascular insult or myocardial infarction) were recorded. The follow-up period ended December 2010.
Related JoVE Video
Streptococcal SpeB Cleaved PAR-1 Suppresses ERK Phosphorylation and Blunts Thrombin-Induced Platelet Aggregation.
PLoS ONE
PUBLISHED: 01-01-2013
Show Abstract
Hide Abstract
The family of 4 related protease-activated receptors (PAR-1, 2, 3 & 4) expressed by mammalian cells allow to sense for and react to extracellular proteolytic activity. Since major human bacterial pathogens secret a wide array of protease(-s) we investigated whether they interfere with human PAR function.
Related JoVE Video
Activated protein C up-regulates procoagulant tissue factor activity on endothelial cells by shedding the TFPI Kunitz 1 domain.
Blood
PUBLISHED: 04-07-2011
Show Abstract
Hide Abstract
Thrombin and activated protein C (APC) signaling can mediate opposite biologic responses in endothelial cells. Given that thrombin induces procoagulant tissue factor (TF), we examined how TF activity is affected by APC. Exogenous or endogenously generated APC led to increased TF-dependent factor Xa activity. Induction required APCs proteolytic activity and binding to endothelial cell protein C receptor but not protease activated receptors. APC did not affect total TF antigen expression or the availability of anionic phospholipids on the apical cell membrane. Western blotting and cell surface immunoassays demonstrated that APC sheds the Kunitz 1 domain from tissue factor pathway inhibitor (TFPI). A TFPI Lys86Ala mutation between the Kunitz 1 and 2 domains eliminated both cleavage and the enhanced TF activity in response to APC in overexpression studies, indicating that APC up-regulates TF activity by endothelial cell protein C receptor-dependent shedding of the Kunitz 1 domain from membrane-associated TFPI. Our results demonstrate an unexpected procoagulant role of the protein C pathway that may have important implications for the regulation of TF- and TFPI-dependent biologic responses and for fine tuning of the hemostatic balance in the vascular system.
Related JoVE Video
High Prevalence of Iron Deficiency among Educated Hospital Employees in Switzerland.
Int J Biomed Sci
PUBLISHED: 03-02-2011
Show Abstract
Hide Abstract
Iron deficiency is known to cause symptoms such as fatigue, depression and restless legs syndrome resulting in impaired quality of life and working capacity. We sought to examine the iron status of reportedly healthy individuals by a framed study design in 58 highly educated Swiss hospital employees and to compare the use of non invasive tests for assessing iron deficiency (ID). A structured interview was used to assess health status, nutritional intake and potential blood loss, blood counts as well as parameters proposed to diagnose iron deficiency were determined. All subjects felt well and were working at their maximum capacity. The male subjects were neither anaemic nor had decreased iron parameters however 50% (23/46) of the women had a serum ferritin of below 22 ?g/L, still 33% (15/46) of the women had a ferritin value below the more stringent cut off value of 15 ?g/L. In 15% (7/46) of the women we diagnosed iron deficient anaemia. Red meat consumption correlated with ferritin values as did the menstrual blood loss which was estimated by asking the amount of tampons used. Of the additionally analysed iron parameters only the percentage of hypochromic erythrocytes, soluble transferrin receptor and transferrin values were significantly correlated with ferritin and reached an AUCROC of ?0.7 indicating good predictive tests. Nevertheless neither soluble transferrin receptor nor transferrin showed diagnostic advantages for the diagnosis of ID compared to ferritin alone or together with erythrocyte parameters. Working in a hospital environment and having access to health education does not seem to correlate with prevention of ID or ID anaemia in female hospital employees.
Related JoVE Video
Importance of Toll-like receptor 9 in host defense against M1T1 group A Streptococcus infections.
J Innate Immun
PUBLISHED: 02-16-2011
Show Abstract
Hide Abstract
Timely recognition and elimination of invasive group A Streptococcus (GAS) by innate immunity is crucial to control infection. The intracellular pattern recognition receptor Toll-like receptor 9 (TLR9) promotes macrophage hypoxia-inducible factor-1? levels, oxidative burst and nitric oxide production in response to GAS. TLR9 contributes to GAS clearance in vivo in both localized cutaneous and systemic infection models.
Related JoVE Video
Contribution of SecDF to Staphylococcus aureus resistance and expression of virulence factors.
BMC Microbiol.
PUBLISHED: 01-20-2011
Show Abstract
Hide Abstract
SecDF is an accessory factor of the conserved Sec protein translocation machinery and belongs to the resistance-nodulation-cell division (RND) family of multidrug exporters. SecDF has been shown in Escherichia coli and Bacillus subtilis to be involved in the export of proteins. RND proteins can mediate resistance against various substances and might be of relevance in antimicrobial therapy. The role of RND proteins in Staphylococcus aureus has not yet been determined.
Related JoVE Video
Thromboelastography to monitor clotting/bleeding complications in patients treated with the molecular adsorbent recirculating system.
Crit Care Res Pract
PUBLISHED: 01-13-2011
Show Abstract
Hide Abstract
Background. The Molecular Adsorbent Recirculating System (MARS) has been shown to clear albumin-bound toxins from patients with liver failure but might cause bleeding complications potentially obscuring survival benefits. We hypothesized that monitoring clotting parameters and bed-side thromboelastography allows to reduce bleeding complications. Methods. Retrospective analysis of 25 MARS sessions during which clotting parameters were monitored by a standardized protocol. Results. During MARS therapy median INR increased significantly from 1.7 to 1.9 platelet count and fibrinogen content decreased significantly from 57?fL(-1) to 42?fL(-1) and 2.1?g/L to 1.5?g/L. Nine relevant complications occurred: the MARS system clotted 6 times 3 times we observed hemorrhages. Absent thrombocytopenia and elevated plasma fibrinogen predicted clotting of the MARS system (ROC 0.94 and 0.82). Fibrinolysis, detected by thromboelastography, uniquely predicted bleeding events. Conclusion. Bed-side thromboelastography and close monitoring of coagulation parameters can predict and, therefore, help prevent bleeding complications during MARS therapy.
Related JoVE Video
Same quality - higher price? The paradox of allocation: the first national single center analysis after the implementation of the new Swiss transplantation law: the ICU view.
Clin Transplant
PUBLISHED: 11-26-2010
Show Abstract
Hide Abstract
This study was undertaken as the first national single-center analysis to assess the impact of the new Swiss transplantation law on patient selection, intensive care unit (ICU) complications, outcome, and, in particular, costs in liver transplant recipients treated in our surgical ICU. The first 35 consecutive liver transplant recipients following the new act were compared with the last 35 liver transplant recipients preceding July 1, 2007. Following execution of the new law, recipients were in poorer condition, reflected by significant higher Model for End-Stage Liver Disease (MELD) scores (12 vs. 22; p = 0.006). Furthermore, the MELD group obtained more renal replacement therapies (40.0% vs. 14.3%; p = 0.015). Cumulative one-yr patient survival was comparable in both groups (91.4% vs. 80.1%, p = 0.22). Finally, the additional costs per single case increased 27 000 Euros after the adoption of the new law. Our data serve as an example that political decisions influence patients selection, and, in turn, complications, finally leading to higher costs of medical treatment. Liver graft allocation according to the MELD system may save lives at the price of increased intensive care efforts.
Related JoVE Video
Two different hematocrit detection methods: different methods, different results?
BMC Res Notes
PUBLISHED: 03-09-2010
Show Abstract
Hide Abstract
Less is known about the influence of hematocrit detection methodology on transfusion triggers. Therefore, the aim of the present study was to compare two different hematocrit-assessing methods. In a total of 50 critically ill patients hematocrit was analyzed using (1) blood gas analyzer (ABLflex 800) and (2) the central laboratory method (ADVIA® 2120) and compared.
Related JoVE Video
Model of end stage liver disease (MELD) score greater than 23 predicts length of stay in the ICU but not mortality in liver transplant recipients.
Crit Care
PUBLISHED: 02-16-2010
Show Abstract
Hide Abstract
The impact of model of end stage liver disease (MELD) score on postoperative morbidity and mortality is still elusive, especially for high MELD. There are reports of poorer patient outcome in transplant candidates with high MELD score, others though report no influence of MELD score on outcome and survival.
Related JoVE Video
Protection of vascular barrier integrity by activated protein C in murine models depends on protease-activated receptor-1.
Thromb. Haemost.
PUBLISHED: 04-08-2009
Show Abstract
Hide Abstract
Protease activated receptor-1 (PAR1) mediates barrier protective signalling of activated protein C (APC) in human endothelial cells in vitro and may contribute to APCs beneficial effects in patients with severe sepsis. Mouse models are of key importance for translational research but species differences may limit conclusions for the human system. We analysed whether mouse APC can cleave, activate and induce signalling through murine PAR1 and tested in newly established mouse models if long-term infusion of APC prevents from vascular leakage. Cell surface immunoassays demonstrated efficient cleavage of endogenous murine endothelial PAR1 by either murine or human APC. Pharmacological concentrations of APC of either species had powerful barrier protective effects on cultured murine endothelial cells that required PAR1 cleavage. Vascular endothelial growth factor-mediated hyperpermeability in the skin was reduced by either endogenously generated as well as directly infused recombinant mouse APC in wild-type mice. However APC did not significantly alter the vascular barrier function in PAR1-deficient mice. In endotoxin-challenged mice, infused APC significantly prevented from pulmonary fluid accumulation in the wild-type mice but not in mice lacking PAR1. Our results directly show that murine APC cleaves and signals through PAR1 in mouse endothelial cells. APC reduces vascular permeability in mouse models and PAR1 plays a major role in mediating these effects. Our data in vitro and in vivo support the paradigm that PAR1 contributes to protective effects of APC on vascular barrier integrity in sepsis.
Related JoVE Video
Hyperantithrombotic, noncytoprotective Glu149Ala-activated protein C mutant.
Blood
PUBLISHED: 02-24-2009
Show Abstract
Hide Abstract
Activated protein C (APC) reduces mortality in severe sepsis patients. APC exerts anticoagulant activities via inactivation of factors Va and VIIIa and cytoprotective activities via endothelial protein C receptor and protease-activated receptor-1. APC mutants with selectively altered and opposite activity profiles, that is, greatly reduced anticoagulant activity or greatly reduced cytoprotective activities, are compared here. Glu149Ala-APC exhibited enhanced in vitro anticoagulant and in vivo antithrombotic activity, but greatly diminished in vitro cytoprotective effects and in vivo reduction of endotoxin-induced murine mortality. Thus, residue Glu149 and the C-terminal region of APCs light chain are identified as functionally important for expression of multiple APC activities. In contrast to Glu149Ala-APC, 5A-APC (Lys191-193Ala + Arg229/230Ala) with protease domain mutations lacked in vivo antithrombotic activity, although it was potent in reducing endotoxin-induced mortality, as previously shown. These data imply that APC molecular species with potent antithrombotic activity, but without robust cytoprotective activity, are not sufficient to reduce mortality in endotoxemia, emphasizing the need for APCs cytoprotective actions, but not anticoagulant actions, to reduce endotoxin-induced mortality. Protein engineering can provide APC mutants that permit definitive mechanism of action studies for APCs multiple activities, and may also provide safer and more effective second-generation APC mutants with reduced bleeding risk.
Related JoVE Video
Programmed death 1 protects from fatal circulatory failure during systemic virus infection of mice.
J. Exp. Med.
Show Abstract
Hide Abstract
The inhibitory programmed death 1 (PD-1)-programmed death ligand 1 (PD-L1) pathway contributes to the functional down-regulation of T cell responses during persistent systemic and local virus infections. The blockade of PD-1-PD-L1-mediated inhibition is considered as a therapeutic approach to reinvigorate antiviral T cell responses. Yet previous studies reported that PD-L1-deficient mice develop fatal pathology during early systemic lymphocytic choriomeningitis virus (LCMV) infection, suggesting a host protective role of T cell down-regulation. As the exact mechanisms of pathology development remained unclear, we set out to delineate in detail the underlying pathogenesis. Mice deficient in PD-1-PD-L1 signaling or lacking PD-1 signaling in CD8 T cells succumbed to fatal CD8 T cell-mediated immunopathology early after systemic LCMV infection. In the absence of regulation via PD-1, CD8 T cells killed infected vascular endothelial cells via perforin-mediated cytolysis, thereby severely compromising vascular integrity. This resulted in systemic vascular leakage and a consequential collapse of the circulatory system. Our results indicate that the PD-1-PD-L1 pathway protects the vascular system from severe CD8 T cell-mediated damage during early systemic LCMV infection, highlighting a pivotal physiological role of T cell down-regulation and suggesting the potential development of immunopathological side effects when interfering with the PD-1-PD-L1 pathway during systemic virus infections.
Related JoVE Video
DNase Sda1 allows invasive M1T1 Group A Streptococcus to prevent TLR9-dependent recognition.
PLoS Pathog.
Show Abstract
Hide Abstract
Group A Streptococcus (GAS) has developed a broad arsenal of virulence factors that serve to circumvent host defense mechanisms. The virulence factor DNase Sda1 of the hyperinvasive M1T1 GAS clone degrades DNA-based neutrophil extracellular traps allowing GAS to escape extracellular killing. TLR9 is activated by unmethylated CpG-rich bacterial DNA and enhances innate immune resistance. We hypothesized that Sda1 degradation of bacterial DNA could alter TLR9-mediated recognition of GAS by host innate immune cells. We tested this hypothesis using a dual approach: loss and gain of function of DNase in isogenic GAS strains and presence and absence of TLR9 in the host. Either DNA degradation by Sda1 or host deficiency of TLR9 prevented GAS induced IFN-? and TNF-? secretion from murine macrophages and contributed to bacterial survival. Similarly, in a murine necrotizing fasciitis model, IFN-? and TNF-? levels were significantly decreased in wild type mice infected with GAS expressing Sda1, whereas no such Sda1-dependent effect was seen in a TLR9-deficient background. Thus GAS Sda1 suppressed both the TLR9-mediated innate immune response and macrophage bactericidal activity. Our results demonstrate a novel mechanism of bacterial innate immune evasion based on autodegradation of CpG-rich DNA by a bacterial DNase.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.