Early Postinterventional Stent Stenosis of a Ductus Stent Implanted for Palliation in a Newborn with Pulmonary Atresia with Intact Ventricular Septum: Successful Management with Bailout Stenting

A newborn with pulmonary atresia with intact ventricular septum (PA-IVS) was treated with radiofrequency current perforation of the atretic pulmonary valve. As the right ventricle was hypoplastic (z-value of the tricuspid valve: —4) the arterial duct was stented with a Gianturco-Roubin GR II stent. Early postinterventionally, the patient became cyunotic and compromised blood flow across the stented ductus arteriosus despite adequate stent position was detected echographically. The newborn was treated successfully with the implantation of a Palmaz stent (Johnson & Johnson Interventional Systems, Warren, NJ, USA) into the obstructed Gianturco-Roubin GR II stent. The Gianturco-Roubin GR II stents might be associated with the risk of early stent stenosis after implantation in actively contracting tissues like the ductus arteriosus. In patients with early stent stenosis after ductal stenting, bailout implantation of a subsequent stent can be performed. Transcatheter procedures can be effective means for therapy of PA-IVS . (J Interven Cardiol 2000;13:39–44)     

Temporal Electrogram Analysis: Algorithm Development

PAUL, V.E., ET AL.: Temporal Electrogram Analysis: Algorithm Development. The automatic discrimination of physiological from pathological tachycardias by rate criteria alone lacks adequate specificity. Tachycardia detection algorithms based upon morphological analysis of the endocardial electrogram have been attributed high specificity although their specificity has not been proven. A previous study had shown temporal electrogram analysis TEA) to be an algorithm of high sensitivity in the detection of ventricular arrhythmias despite low computational demands. In this study, the specificity and potential for automatic implementation have been assessed. Manual adjustment of thresholds for individual patients gave a maximum potential sensitivity of 97% (26/27 arrhythmias correctly recognized as non-sinus). The use of automatic setting of thresholds reduced sensitivity to 81%. The specificity of the algorithm, as assessed by exercise testing, was only 60%.     

Generation of self‐renewing immature dendritic cells from mouse spleen that can take up mycobacteria and present antigens to T cells

Pal R, Marwaha S, Pepponi I, Mann JFS, Paul MJ, Reljic R. Generation of self‐renewing immature dendritic cells from mouse spleen that can take up mycobacteria and present antigens to T cells. APMIS 2010; 118: 729–38. Dendritic cells (DC) play a key role in driving the adaptive immune response to Mycobacterium tuberculosis (MTB), the causative pathogen of tuberculosis (TB). However, studying these important yet very sparse immune cells in the context of MTB pathogenesis is severely restricted by the lack of suitable cell lines and the complexity of culturing of DC progenitors, usually obtained from the bone marrow. However, significant advances have been made towards generating long‐term DC cultures from various lymphoid tissues. Here, we report the evidence for generating a long‐term, self‐renewing DC culture from the Balb/c mouse spleen. We demonstrate that these cells, termed IDC‐3, have a myeloid DC origin, i.e. they are CD11c⁺CD11b⁺⁺CD8‐α^?F4/80^+/? and that they also display a phenotype MHC‐II⁺CD16/32⁺⁺CD80^+/?CD86⁺, indicating that they are immature DC. Following incubation with Mycobacterium bovis BCG (Bacillus Calmette Guerin), the IDC‐3 efficiently took up bacteria and acquired the morphology of mature DC. Importantly though, when IDC‐3 were pre‐stimulated with a mycobacterial antigen in vitro, they were able to induce proliferation of T lymphocytes from mice immunized with the same antigen. The T‐cell stimulatory potential of IDC‐3 was further enhanced when the cells were co‐stimulated with an anti‐CD40 mAb. We therefore suggest that the IDC‐3 culture system could be a useful tool for studying the interaction of DC with mycobacteria.     

Endothelial dysfunction:EDCF revisited

Endothelial cells can initiate contraction(constriction)of the vascular smooth muscle cells that surround them.Such endothelium-dependent,acute increases in contractile tone can be due to the withdrawal of the production of nitric oxide,to the production of vasoconstrictor peptides(angiotensin II,endothelin-1),to the formation of oxygen-derived free radicals(superoxide anions)and/or the release of vasoconstrictor metabolites of arachidonic acid.The latter have been termed endothelium-derived contracting factor(EDCF)as they can contribute to moment-to-moment changes in contractile activity of the underlying vascular smooth muscle cells.To judge from animal experiments,EDCF-mediated responses are exacerbated when the production of nitric oxide is impaired as well as by aging,spontaneous hypertension and diabetes.To judge from human studies,they contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive patients.Since EDCF causes vasoconstriction by activation of the TP-receptors on the vascular smooth muscle cells,selective antagonists at these receptors prevent endothelium-dependent contractions,and curtail the endothelial dysfunction in hypertension and diabetes.     

Use of an Autologous Blood Recovery System during Emergency Pericardiocentesis in the Electrophysiology Laboratory

Introduction: Emergency pericardiocentesis during electrophysiology procedures is often associated with significant aspiration of pericardial blood, requiring transfusion. We sought to assess the feasibility of urgent use of an autologous blood recovery system in the electrophysiology laboratory to autotransfuse blood aspirated from the pericardium.
Methods and Results: We retrospectively analyzed Mayo Clinic electrophysiology records for patients who had ablation procedure-related pericardial effusions requiring emergency pericardial drainage during an 8-month period. An autologous blood recovery system was used during pericardiocentesis to separate and clean packed red blood cells from the pericardial aspirate. These cells were returned acutely to the patient intravenously. The procedural safety, aspirated and autotransfused volumes, and efficacy of this approach were evaluated. During the study period, nine patients underwent pericardial drainage with autotransfusion using a cell-salvage instrument during electrophysiology procedures. The mean aspirated volume was 1,078 mL, with a mean autotransfused volume of 390 mL. For four patients, all with aspirated volumes of 1,100 mL or less, autotransfusion alone was sufficient to maintain hemodynamic stability and avoid allogeneic transfusion. One patient required surgical intervention because of ongoing pericardial bleeding. The ablation procedure was completed after aspiration in two patients. No procedural complications related to the use of the cell-salvage system occurred. 
Conclusion: Autologous blood recovery during pericardiocentesis is safe, convenient, and feasible. With early use it may decrease or eliminate the need for allogeneic blood transfusion and, in selected cases, may permit completion of the ablation procedure.     

Problems associated with use of the benzyloxymethyl protecting group for histidines Formaldehyde adducts formed during cleavage by hydrogen fluoride 1

The use of N^α-tert.-butyloxycarbonyl-N^π benzyloxymethylhistidine in peptide synthesis resulted in significant levels of several different side products attributable to the generation of formaldehyde during the hydrogen fluoride cleavage reaction. Methylated impurities in a decapeptide were isolated and identified. These methylated impurities were attributed to the use of the benzyloxymethyl protecting group for the histidines, since the impurities did not form when the dinitrophenyl protecting group was used. Also, peptides containing benzyloxymethyl-protected histidines in addition to N-terminal cysteines quantitatively yielded their respective N-terminal thiazolidine derivatives upon isolation from standard hydrogen fluoride cleavage mixtures. Thiazolidine ring formation was circumvented by including in the cleavage reaction a formaldehyde scavenger such as cysteine hydrochloride or resorcinol.