Selective Valve Removal for Melody Valve Endocarditis: Practice Variations in a Multicenter Experience.

Guidelines for management of Melody transcatheter pulmonary valve (TPV) infective endocarditis (IE) are lacking. We aimed to identify factors associated with surgical valve removal versus antimicrobial therapy in Melody TPV IE. Multicenter retrospective analysis of all patients receiving Melody TPV from 10/2010 to 3/2019 was performed to identify cases of IE. Surgical explants versus non-surgical cases were compared. Of the 663 Melody TPV implants, there were 66 cases of IE in 59 patients (59/663, 8.8%). 39/66 (59%) were treated with IV antimicrobials and 27/66(41%) underwent valve explantation. 26/59 patients (44%) were treated medically without explantation or recurrence with average follow-up time of 3.5 years (range:1-9). 32% of Streptococcus cases, 53% of MSSA, and all MRSA cases were explanted. 2 of the 4 deaths had MSSA. CART analysis demonstrated two important parameters associated with explantation: a peak echo gradient ≥ 47 mmHg at IE diagnosis(OR 10.6, p < 0.001) and a peak echo gradient increase of > 24 mmHg compared to baseline (OR 6.7, p = 0.01). Rates of explantation varied by institution (27 to 64%). In our multicenter experience, 44% of patients with Melody IE were successfully medically treated without valve explantation or recurrence. The degree of valve stenosis at time of IE diagnosis was strongly associated with explantation. Rates of explantation varied significantly among the institutions.

Comparison of the investigational device exemption and post-approval trials of the Melody transcatheter pulmonary valve.

OBJECTIVE: We compared 5-year outcomes of transcatheter pulmonary valve (TPV) replacement with the Melody TPV in the post-approval study (PAS) and the investigational device exemption (IDE) trial. BACKGROUND: As a condition of approval of the Melody TPV after the IDE trial, the Food and Drug Administration required that a PAS be conducted to evaluate outcomes of TPV replacement in a "real-world" environment. The 5-year outcomes of the PAS have not been published, and the IDE and PAS trials have not been compared. METHODS: The cohorts comprised all patients catheterized and implanted at 5 IDE sites and 10 PAS sites. Differences in trial protocols were detailed. Time-related outcomes and valve-related adverse events were compared between the two trials with Kaplan-Meier curves and log-rank testing. RESULTS: 167 patients (median age, 19 years) were catheterized and 150 underwent TPV replacement in the IDE trial; 121 were catheterized (median age, 17 years) and 100 implanted in the PAS. Freedom from hemodynamic dysfunction (p = .61) or any reintervention (p = .74) over time did not differ between trials. Freedom from stent fracture (p = .003) and transcatheter reintervention (p = .010) were longer in PAS, whereas freedom from explant (p = .020) and TPV endocarditis (p = .007) were shorter. Clinically important adverse events (AEs) were reported in 14% of PAS and 7.2% of IDE patients (p = .056); the incidence of any particular event was low in both. CONCLUSIONS: Hemodynamic and time-related outcomes in the PAS and IDE trials were generally similar, confirming the effectiveness of the Melody TPV with real-world providers. There were few significant complications and limited power to identify important differences in AEs. The lack of major differences in outcomes between the two studies questions the usefulness of mandated costly post-approval studies as part of the regulatory process for Class III medical devices.

Infants with pulmonary atresia intact ventricular septum who require balloon atrial septostomy have significantly higher 18-month mortality.

INTRODUCTION: Many newborns with pulmonary atresia/intact ventricular septum require intervention to establish pulmonary flow and sufficient cardiac output. The resulting haemodynamic changes are not well characterised and may have unintended consequences. METHODS: This is a 30-year (1988-2018) retrospective study of patients with pulmonary atresia intact ventricular septum. RESULTS: Eighty-nine patients were included, and median follow-up was 8 years. Fifty-five per cent had coronary sinusoids and 27% had right ventricular-dependent coronary circulation. Most patients were managed with surgical aortopulmonary or modified Blalock-Taussig shunt (73%), and 12 patients underwent balloon atrial septostomy before surgical intervention. The remaining patients (27%) underwent only transcatheter interventions; 7 required an atrial septostomy and 17 required ductal stentings. All-cause mortality was 10%, most deaths (89%) occurred before 18 months of age. Of these early deaths, 87% required a balloon atrial septostomy and 85% had right ventricular-dependent coronary sinusoids. Eighteen-month mortality was significantly higher for patients who required a balloon atrial septostomy compared to those who did not (36% versus 1.4% p < 0.0001). DISCUSSION: Patients with pulmonary atresia/intact ventricular septum who require balloon atrial septostomy in the newborn period have significantly higher 18-month mortality. Quantifying the mortality difference may help guide prognostication and expectation setting. Infants who had septostomy and a surgical shunt in the newborn period fared better than those who only underwent septostomy (even when accompanied by ductal stenting). For infants with right ventricular-dependent circulation, atrial septostomy should only be performed on an urgent or emergent basis and these patients should be considered for early surgical intervention and neonatal transplant.

Early experience with the Micro Plug Set for preterm patent ductus arteriosus closure.

OBJECTIVES: We intend to describe early experience using a new, commercially available Micro Plug Set for preterm neonate and infant transcatheter patent ductus arteriosus (PDA) occlusion. BACKGROUND: Transcatheter PDA occlusion in premature neonates and small infants is safe and effective. The procedure is early in its evolution. METHODS: Procedural and short-term outcomes of preterm neonates and infants undergoing transcatheter PDA occlusion with a new, commercially available device were reviewed. RESULTS: Eight preterm neonates and infants born at median 27 weeks gestation (23-36 weeks) underwent transcatheter PDA device closure with the Micro Plug Set. The device is short (2.5 mm) with a range of diameters (3, 4, 5, 6 mm) and delivered through a microcatheter. Procedures were performed at median 41 days of age (12-88 days) and at 1690 g (760-3,310 g). Transvenous PDA device occlusion was performed with fluoroscopic and echocardiography guidance. All procedures were successful with complete PDA occlusion. There were no procedural or short-term adverse events. CONCLUSIONS: Preterm neonate and infant transcatheter PDA device closure with a new, commercially available short and microcatheter delivered device (Micro Plug Set) was safe and effective in a small, early series of patients.

Bronchus compression relieved by patent ductus arteriosus stenting.

BACKGROUND: Patent ductus arteriosus (PDA) stenting is evolving as an alternative to surgical aorto-pulmonary shunts for infants with ductal-dependent pulmonary blood flow. Given anatomical proximity, the PDA can compress the ipsilateral bronchus. We report a case series of four patients with bronchial compression by a tortuous PDA who underwent PDA stenting. METHODS: Our four patients received PDA stents for ductal-dependent pulmonary blood flow despite preprocedure imaging evidence of bronchial compression. We reviewed the cross-sectional chest imaging to assess the degree of bronchial compression and the variables that affect it, namely PDA size, PDA tortuosity, and the anatomical relationship between the compressed bronchus and the PDA. RESULTS: Three out of the four patients had postprocedure imaging, and all showed relief of the previously seen bronchial compression. Post-PDA stenting patients had a smaller and straight PDA with significant lateralization away from the compressed bronchus. None of the four patients developed symptoms of bronchial compression poststenting. CONCLUSIONS: Our study suggests that pre-existing bronchial compression does not preclude PDA stenting. Stent placement in an engorged and tortuous PDA led to significant improvement in pre-existing bronchial compression. Improvement may be attributed to PDA shrinkage, straightening, and lateralization. Further studies are needed to confirm our findings.

Association between patient age at implant and outcomes after transcatheter pulmonary valve replacement in the multicenter Melody valve trials.

OBJECTIVES: To investigate whether age and valve size at implant contribute to outcomes after Melody transcatheter pulmonary valve replacement (TPVR). BACKGROUND: Patient age and valve size at implant contribute to longevity of surgical pulmonary valves. METHODS: All patients discharged with a Melody valve in the pulmonary position, as part of three prospective Melody valve multicenter studies, comprised the study cohort. Acute and time-related outcomes were analyzed according to age: children (≤12 years), adolescents (13-18 years), young adults (19-29 years), and older adults (≥30 years). RESULTS: Successful Melody valve implantation occurred in 49 children, 107 adolescents, 96 young adults, and 57 older adults. Pediatric patients (≤18 years) were more likely to have TPVR for conduit stenosis than adults (62% vs. 44%); children had the smallest conduits. After TPVR, pediatric and adult patients had similar decreases in right ventricular (RV) size by MRI, but adults had improved percentage predicted peak VO2 (58% preimplant to 64% postimplant, p = .02) and FEV1 (69% pre to 71% post, p = .005). Younger age was associated with shorter freedom from RVOT dysfunction, reintervention, and explant. Children had the shortest freedom from endocarditis (p = .041), but all other groups had 5-year freedom from endocarditis of ≥90%. CONCLUSIONS: Younger age was associated with shorter time to RVOT dysfunction, reintervention, and explant after Melody TPVR. Patients ≥13 years of age were at low risk for endocarditis and explant to 5 years. A better understanding of time-related outcomes by age will aid in the comparison of therapeutic options for TPVR candidates. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT00740870 (NCT00740870), https://clinicaltrials.gov/ct2/show/NCT01186692 (NCT01186692), and https://clinicaltrials.gov/ct2/show/NCT00688571 (NCT00688571).

Results of the combined U.S. multicenter postapproval study of the Nit-Occlud PDA device for percutaneous closure of patent ductus arteriosus.

OBJECTIVES: To report the results of the Nit-Occlud PDA prospective postapproval study (PAS) along with a comparison to the results of the pivotal and continued access trials. BACKGROUND: The Nit-Occlud PDA (PFM Medical, Cologne, Germany), a nitinol coil patent ductus arteriosus (PDA) occluder, was approved by the Food and Drug Administration in 2013. METHODS: The PAS enrolled a total of 184 subjects greater than 6 months of age, weighing at least 5 kg, with PDAs less than 4 mm by angiography at 11 centers. Patients were followed prospectively at 2 months, 12 months, and 24 months postprocedure. These outcomes were compared to the 357 subjects enrolled in the pivotal and continued access protocols. Efficacy and safety data were reported. RESULTS: Among 184 subjects enrolled for the PAS between 2014 and 2017, 180 (97.8%) had successful device implantation. After 12 months, 98.7% (150/152) had trivial or no residual shunt by echocardiography and two subjects had only small residual shunts. There were three device embolizations that were all retrieved by snare without clinical consequence. Together with the pivotal and continued access study, 97.4% (449/461) had complete echocardiographic closure at 12 months in 541 enrolled subjects. The composite success was 94.4%. There were no mortalities and no serious device-related adverse events. CONCLUSIONS: The Nit-Occlud PDA is a safe and effective device for closure of a small to moderate sized PDA. There were no serious device-related adverse events in a large cohort of three clinical trials.

Non-anastomotic failure of woven Dacron tube grafts in the thoracic aorta in young adults.

BACKGROUND: Dacron tube grafts have been used in the surgical management of cardiovascular disease since the 1970s. Complications at the site of the anastomosis have been well described. Non-anastomotic failure is far less common. We present a series of four patients who presented with complications of non-anastomotic failure of woven Dacron tube grafts. METHODS: A retrospective chart review of four patients who presented to our institution between March 2014 and March 2017 with clinical complications of a Dacron tube graft was conducted. RESULTS: All four patients underwent a staged surgical repair for an interrupted aortic arch between the years of 1988 and 2001. All four patients underwent revision of their original interposition graft (Gore-Tex, W.L. Gore & Associates, Flagstaff, AZ) with implantation of a Hemashield woven Dacron tube graft (Maquet, Rastatt, Germany). From 13 to 22 years postimplant of the Dacron tube graft, all patients presented with symptoms or clinical evidence of primary graft failure. Two patients underwent urgent surgical intervention and did not survive. One patient underwent attempted surgical intervention, which was aborted in the setting of profuse bleeding, and ultimately had an endovascular rescue of the tube graft with a Zenith Alpha endograft (Cook Medical, Bloomington, IN). One patient underwent elective endovascular intervention prior to onset of symptoms. CONCLUSION: Non-anastomotic failure of woven Dacron tube grafts can occur in the thoracic aorta in young adults and may be managed with endovascular techniques.

Stenting of the ascending aorta revisited.

Despite few institutions stenting the ascending aorta, it has been discouraged because of the proximity of the aortic valve, the coronary artery orifices, and the aortic arch branches. We describe a small case series of patients having acquired stenosis of the ascending that was relieved successfully by stenting. © 2017 Wiley Periodicals, Inc.

Percutaneous obliteration of left ventricular cavity to eliminate aortic regurgitation and presumed coronary steal in an infant with hypoplastic left heart syndrome.

The phenomenon of coronary steal is well known in the setting of HLHS (Hypoplastic Left Heart Syndrome) early after the Classical Norwood Operation. We report a rare case of an infant with HLHS [Severe Aortic Stenosis (AS), Mitral Stenosis (MS) and small Left Ventricle (LV)], who developed aortic regurgitation and presumed coronary steal late after the Sano Modification of the Norwood Procedure. Coronary steal developed secondary to progressive aortic and mitral regurgitation and resulted in poor right ventricular function and severe tricuspid regurgitation. We describe a novel interventional approach for obliteration of the LV cavity by using hydrogel coils. LV obliteration eliminated the presumed steal and resulted in improvement in ventricular function, tricuspid regurgitation and clinical course.

S-nitrosylation of NADPH oxidase regulates cell death in plant immunity.

Changes in redox status are a conspicuous feature of immune responses in a variety of eukaryotes, but the associated signalling mechanisms are not well understood. In plants, attempted microbial infection triggers the rapid synthesis of nitric oxide and a parallel accumulation of reactive oxygen intermediates, the latter generated by NADPH oxidases related to those responsible for the pathogen-activated respiratory burst in phagocytes. Both nitric oxide and reactive oxygen intermediates have been implicated in controlling the hypersensitive response, a programmed execution of plant cells at sites of attempted infection. However, the molecular mechanisms that underpin their function and coordinate their synthesis are unknown. Here we show genetic evidence that increases in cysteine thiols modified using nitric oxide, termed S-nitrosothiols, facilitate the hypersensitive response in the absence of the cell death agonist salicylic acid and the synthesis of reactive oxygen intermediates. Surprisingly, when concentrations of S-nitrosothiols were high, nitric oxide function also governed a negative feedback loop limiting the hypersensitive response, mediated by S-nitrosylation of the NADPH oxidase, AtRBOHD, at Cys 890, abolishing its ability to synthesize reactive oxygen intermediates. Accordingly, mutation of Cys 890 compromised S-nitrosothiol-mediated control of AtRBOHD activity, perturbing the magnitude of cell death development. This cysteine is evolutionarily conserved and specifically S-nitrosylated in both human and fly NADPH oxidase, suggesting that this mechanism may govern immune responses in both plants and animals.

Methodology for reliable and reproducible cryopreservation of human cervical tissue.

BACKGROUND: In order to conduct laboratory studies on donated cervical tissue at suitable times an effective and reliable cryopreservation protocol for cervical tissue is required. METHODS: An active freezing approach was devised utilising 10% dimethyl sulfoxide in foetal bovine serum as a cryoprotective agent with a cooling rate of 1 °C/min to -50 °C then 10 °C/min to -120 °C; a related thawing protocol was also optimised which would allow for the bio-banking of cervical tissue. Viability of freshly harvested cervical tissue was compared to frozen-thawed samples utilising colorimetric MTT assay. In parallel, fresh and freeze-thawed samples were cultured and tested on days 1, 7 and 14 to determine whether bio-banking had detrimental effects on tissue viability over time. RESULTS: Repeat testing revealed that tissue viability between fresh and freeze-thawed samples was comparable at all four time points (days 0, 1, 7 and 14) with no apparent reductions of viability, thus demonstrating this method of cryopreserving cervical tissue is reliable and reproducible, without detrimental effects on live tissue culture. We believe this methodology creates the opportunity for bio-banking donated cervical tissues, which aids improved experimental design and reduces time pressures and wastage.

Adjusting for Risk Associated With Pediatric and Congenital Cardiac Catheterization: A Report From the NCDR IMPACT Registry.

BACKGROUND: As US health care increasingly focuses on outcomes as a means for quantifying quality, there is a growing demand for risk models that can account for the variability of patients treated at different hospitals so that equitable comparisons between institutions can be made. We sought to apply aspects of prior risk-standardization methodology to begin development of a risk-standardization tool for the National Cardiovascular Data Registry (NCDR) IMPACT (Improving Pediatric and Adult Congenital Treatment) Registry. METHODS AND RESULTS: Using IMPACT, we identified all patients undergoing diagnostic or interventional cardiac catheterization between January 2011 and March 2013. Multivariable hierarchical logistic regression was used to identify patient and procedural characteristics predictive of experiencing a major adverse event after cardiac catheterization. A total of 19,608 cardiac catheterizations were performed between January 2011 and March 2013. Among all cases, a major adverse event occurred in 378 of all cases (1.9%). After multivariable adjustment, 8 variables were identified as critical for risk standardization: patient age, renal insufficiency, single-ventricle physiology, procedure-type risk group, low systemic saturation, low mixed venous saturation, elevated systemic ventricular end-diastolic pressure, and elevated main pulmonary artery pressures. The model had good discrimination (C statistic, 0.70), confirmed by bootstrap validation (validation C statistic, 0.69). CONCLUSIONS: Using prior risk-standardization efforts as a foundation, we developed and internally validated a model to predict the occurrence of a major adverse event after cardiac catheterization for congenital heart disease. Future efforts should be directed toward further refinement of the model variables within this large, multicenter data set.

Bone marrow-derived and resident liver macrophages display unique transcriptomic signatures but similar biological functions.

BACKGROUND & AIMS: Kupffer cells (KCs), the resident tissue macrophages of the liver, play a crucial role in the clearance of pathogens and other particulate materials that reach the systemic circulation. Recent studies have identified KCs as a yolk sac-derived resident macrophage population that is replenished independently of monocytes in the steady state. Although it is now established that following local tissue injury, bone marrow derived monocytes may infiltrate the tissue and differentiate into macrophages, the extent to which newly differentiated macrophages functionally resemble the KCs they have replaced has not been extensively studied. METHODS: We studied the two populations of KCs using intravital microscopy, morphometric analysis and gene expression profiling. An ion homeostasis gene signature, including genes associated with scavenger receptor function and extracellular matrix deposition, allowed discrimination between these two KC sub-types. RESULTS: Bone marrow derived "KCs" accumulating as a result of genotoxic injury, resemble but are not identical to their yolk sac counterparts. Reflecting the differential expression of scavenger receptors, yolk sac-derived KCs were more effective at accumulating acetylated low density lipoprotein, whereas surprisingly, they were poorer than bone marrow-derived KCs when assessed for uptake of a range of bacterial pathogens. The two KC populations were almost indistinguishable in regard to i) response to lipopolysaccharide challenge, ii) phagocytosis of effete red blood cells and iii) their ability to contain infection and direct granuloma formation against Leishmania donovani, a KC-tropic intracellular parasite. CONCLUSIONS: Bone marrow-derived KCs differentiate locally to resemble yolk sac-derived KC in most but not all respects, with implications for models of infectious diseases, liver injury and bone marrow transplantation. In addition, the gene signature we describe adds to the tools available for distinguishing KC subpopulations based on their ontology. LAY SUMMARY: Liver macrophages play a major role in the control of infections in the liver and in the pathology associated with chronic liver diseases. It was recently shown that liver macrophages can have two different origins, however, the extent to which these populations are functionally distinct remains to be fully addressed. Our study demonstrates that whilst liver macrophages share many features in common, regardless of their origin, some subtle differences in function exist. DATA REPOSITORY: Gene expression data are available from the European Bioinformatics Institute ArrayExpress data repository (accession number E-MTAB-4954).

Differential Requirements for IL-17A and IL-22 in Cecal versus Colonic Inflammation Induced by Helicobacter hepaticus.

Type 17 helper T-cell cytokines have been implicated in the pathogenesis of inflammatory bowel disease, a chronic condition affecting the gastrointestinal tract, but information regarding their contribution to pathology in different regions of the gut is lacking. By using a murine model of bacteria-induced typhlocolitis, we investigated the role of IL-17A, IL-17F, and IL-22 in cecal versus colonic inflammation. Cecal, but not colonic, pathology in C57BL/6 mice inoculated with Helicobacter hepaticus plus anti-IL-10 receptor (IL-10R) monoclonal antibody was exacerbated by co-administration of anti-IL-17A monoclonal antibody, suggesting a disease-protective role for IL-17A in the cecum. In contrast, anti-IL-17F had no effect on H. hepaticus-induced intestinal pathology. Neutralization of IL-22 prevented the development of colonic, but not cecal, inflammation in H. hepaticus-infected anti-IL-10R-treated mice, demonstrating a pathogenic role for IL-22 in the colon. Analysis of transcript levels revealed differential expression of IL-22R, IL-22 binding protein, and IL-23R between cecum and colon, a finding that may help explain why these tissues respond differently after anti-IL-22 treatment. Analysis of microarray data from healthy human intestine further revealed significant differences in cytokine receptor transcript levels (including IL-22RA1 and IL-23R) in distinct parts of the human gut. Together, our findings demonstrate that individual type 17 helper T-cell cytokines can have proinflammatory or anti-inflammatory effects in different regions of the intestine, an observation that may have implications for interventions against human inflammatory bowel disease.

Enhancing the Hodgkin-Huxley Equations: Simulations Based on the First Publication in the Biophysical Journal.

The experiments in the Cole and Moore article in the first issue of the Biophysical Journal provided the first independent experimental confirmation of the Hodgkin-Huxley (HH) equations. A log-log plot of the K current versus time showed that raising the HH variable n to the sixth power provided the best fit to the data. Subsequent simulations using n(6) and setting the resting potential at the in vivo value simplifies the HH equations by eliminating the leakage term. Our article also reported that the K current in response to a depolarizing step to ENa was delayed if the step was preceded by a hyperpolarization. While the interpretation of this phenomenon in the article was flawed, subsequent simulations show that the effect completely arises from the original HH equations.

Comparison of ductal stenting versus surgical shunts for palliation of patients with pulmonary atresia and intact ventricular septum.

OBJECTIVES: We sought to compare ductal stenting (DS) to systemic-pulmonary artery shunt (SPS) in a contemporary cohort of patients having pulmonary atresia with intact ventricular septum (PAIVS). BACKGROUND: Alternative palliative strategies (interventional versus surgical) are currently available for initial palliation of ductal dependent patients with various forms of congenital heart disease. There is little data available to guide strategy selection. METHODS: A retrospective review of patients with PAIVS at our institution from Jan 2006 to Dec 2013 was performed. Demographic, echocardiographic, procedural, and follow-up data were reviewed and analyzed. RESULTS: Twenty-nine patients were identified. Thirteen underwent DS and 16 underwent SPS. In the DS group, 6 had radiofrequency perforation of the pulmonary valve, and 12 underwent balloon pulmonary valvuloplasty (BPV) prior to DS. SPS was performed after perforation of the pulmonary valve in 1 patient and after BPV in 4 patients. Procedural success was 92.8% in the DS group versus 93.3% in the SPS group. In the DS group, one patient required emergency shunting due to intra-procedural ductal spasm. In the SPS group there was one procedure related death, and there were six significant procedure-related complications. Five patients required re-interventions prior to hospital discharge. The median length of hospital stay for the DS versus SPS group was 10 versus 23 days, respectively (P < 0.05). Post discharge, there were seven reinterventions in the DS group and two reinterventions in the SPS group. CONCLUSIONS: DS may provide a safe and effective alternative to SPS in selected patients with PAIVS.

Transcatheter stenting of the systemic-to-pulmonary artery shunt: A 7-year experience from a single tertiary center.

BACKGROUND: Systemic-to-pulmonary artery shunt (SPS) dysfunction can be deleterious in shunt dependent patients and traditionally have undergone surgical revision. Data on transcatheter stenting of SPS is limited. We sought to evaluate feasibility, safety and outcomes of stenting SPS. METHODS: Retrospective review of all patients who underwent transcatheter SPS stenting from 1/2006 to 12/2013. RESULTS: Of 229 surgically implanted SPS, 25 transcatheter stent interventions were performed in 22 patients. The majority had pulmonary atresia (n = 9) or HLHS (n = 10). Their median age was 4 ms (range 10 days to 4 years) and median weight 4.9 kg (range 3-14). Nine had a central and 15 had a BT shunt with a median shunt size of 3.75 mm (range 3-6). The interval from shunt placement to intervention was 1.9 ms (range 4 days-3.8 years). The indication for intervention was increasing cyanosis in10 patients and delaying final repair in 9. Two patients were on ECMO at the time of intervention. The median shunt diameter increased from 2.3 to 4.1 mm and oxygen saturation from 72 to 85% (P < 0.001). No intra-procedural complications were encountered. One patient died from aspiration (autopsy demonstrated a patent shunt), 13 progressed to repair or next stage, 6 remain palliated with shunts as they are deemed unfit for the next stage and 2 are awaiting surgery. CONCLUSIONS: Stenting of systemic to pulmonary artery shunt is a safe and effective procedure and avoids surgical re-intervention. It can be performed both as a rescue procedure in patients with acute shunt occlusion and as an elective procedure to palliate patients not yet suitable for subsequent corrective or staged repair.

IL-10-producing Th1 cells and disease progression are regulated by distinct CD11c⁺ cell populations during visceral leishmaniasis.

IL-10 is a critical regulatory cytokine involved in the pathogenesis of visceral leishmaniasis caused by Leishmania donovani and clinical and experimental data indicate that disease progression is associated with expanded numbers of CD4⁺ IFNγ⁺ T cells committed to IL-10 production. Here, combining conditional cell-specific depletion with adoptive transfer, we demonstrate that only conventional CD11c(hi) DCs that produce both IL-10 and IL-27 are capable of inducing IL-10-producing Th1 cells in vivo. In contrast, CD11c(hi) as well as CD11c(int/lo) cells isolated from infected mice were capable of reversing the host protective effect of diphtheria toxin-mediated CD11c⁺ cell depletion. This was reflected by increased splenomegaly, inhibition of NO production and increased parasite burden. Thus during chronic infection, multiple CD11c⁺ cell populations can actively suppress host resistance and enhance immunopathology, through mechanisms that do not necessarily involve IL-10-producing Th1 cells.

Transcription dynamics in plant immunity.

Plant cells maintain sophisticated gene transcription programs to regulate their development, communication, and response to the environment. Environmental stress cues, such as pathogen encounter, lead to dramatic reprogramming of transcription to favor stress responses over normal cellular functions. Transcription reprogramming is conferred by the concerted action of myriad transcription (co)factors that function directly or indirectly to recruit or release RNA Polymerase II. To establish an effective defense response, cells require transcription (co)factors to deploy their activity rapidly, transiently, spatially, and hierarchically. Recent findings suggest that in plant immunity these requirements are met by posttranslational modifications that accurately regulate transcription (co)factor activity as well as by sequential pulse activation of specific gene transcription programs that provide feedback and feedforward properties to the defense gene network. Here, we integrate these recent findings from plant defense studies into the emerging field of transcription dynamics in eukaryotes.