Impact of COVID-19 disease on clinical research in pediatric and congenital cardiology

BACKGROUND

COVID-19 triggered an unprecedented crisis affecting society at every level. Research in pediatric and congenital cardiology is currently in full development and may have been disrupted. The aim of the study was to determine the impact of COVID-19 on pediatric and congenital cardiology clinical research and to analyze decision-making and adaptation processes, from a panel of ongoing academic and industry-sponsored research at the time of the pandemic.

METHODS

This observational study was carried out in April 2020, from a CHD clinical research network involving five tertiary care pediatric and congenital cardiology centers. Investigators and clinical research assistants from each participating research center completed an online survey questionnaire, and each principal investigator underwent a 1-h web-based videoconference interview.

RESULTS

A total of 34 study questionnaires were collected, reporting that 18 studies were totally suspended. Upon the investigator's decision, after discussion on ethical issues and with facilitating support from health authorities, 16 studies were resumed. The rate of study suspension in interventional research (53%) was similar to that in non-interventional research (56%). Logistical problems were predominantly reported in both continued and suspended trials. Research protocols were adapted, largely thanks to telemedicine, which in some cases even improved the course of the study.

CONCLUSION

The impact of the COVID-19 pandemic on clinical research in pediatric and congenital cardiology has been limited by a rapid adaptation of all research structures and an extensive use of telemedicine at all stages of the studies.

The use of Impella 2.5 in severe refractory cardiogenic shock complicating an acute myocardial infarction

OBJECTIVES

To investigate the outcome of patients with acute myocardial infarction (AMI) complicated by refractory cardiogenic shock (CS) who underwent mechanical circulatory support with Impella 2.5.

BACKGROUND

AMI complicated by CS remains a highly fatal condition. A potent and minimally invasive left ventricular assist device might improve patient outcomes.

METHODS

We analyzed the procedural characteristics and outcomes of 22 consecutive patients who underwent, between July 2008 and December 2012, a percutaneous coronary intervention and Impella 2.5 support for AMI complicated by CS refractory to first-line therapy with inotropes and/or Intra-aortic balloon pump.

RESULTS

In this analysis, patients were relatively young with a mean age of 57.9 ± 11.6 year old and 59.1% were male. The majority of patients (77.3%) were admitted in CS and 40.9% sustained cardiac arrest prior to admission. Hemodynamics improved significantly upon initiation of support, end-organ and tissue perfusion improved subsequently demonstrated by a significant decrease in lactate levels from 6.37 ± 5.3 mmol/L to 2.41 ± 2.1 mmo/L, (P =  0.008) after 2 days of support. Thirteen (59.1%) patients were successfully weaned-off Impella 2.5 and 4 (18.2%) were transitioned to another device. We observed a functional recovery of the left ventricle when compared to baseline (43 ± 10% vs. 27 ± 9%, P < 0.0001). The survival rate at 6 months and 1 year was 59.1% and 54.5%, respectively.

CONCLUSION

Impella 2.5 was initiated as a last resort therapy to support very sick patients with refractory CS after failed conventional therapy. The use of the device yielded favorable short and mid-term survival results with recovery being the most frequently observed outcome.

Characteristics of ventricular tachycardia ablation in patients with continuous flow left ventricular assist devices

BACKGROUND

Left ventricular assist devices (LVADs) are increasingly used as a bridge to cardiac transplantation or as destination therapy. Patients with LVADs are at high risk for ventricular arrhythmias. This study describes ventricular arrhythmia characteristics and ablation in patients implanted with a Heart Mate II device.

METHODS AND RESULTS

All patients with a Heart Mate II device who underwent ventricular arrhythmia catheter ablation at 9 tertiary centers were included. Thirty-four patients (30 male, age 58±10 years) underwent 39 ablation procedures. The underlying cardiomyopathy pathogenesis was ischemic in 21 and nonischemic in 13 patients with a mean left ventricular ejection fraction of 17%±5% before LVAD implantation. One hundred and ten ventricular tachycardias (VTs; cycle lengths, 230-740 ms, arrhythmic storm n=28) and 2 ventricular fibrillation triggers were targeted (25 transseptal, 14 retrograde aortic approaches). Nine patients required VT ablation <1 month after LVAD implantation because of intractable VT. Only 10/110 (9%) of the targeted VTs were related to the Heart Mate II cannula. During follow-up, 7 patients were transplanted and 10 died. Of the remaining 17 patients, 13 were arrhythmia-free at 25±15 months. In 1 patient with VT recurrence, change of turbine speed from 9400 to 9000 rpm extinguished VT.

CONCLUSIONS

Catheter ablation of VT among LVAD recipients is feasible and reasonably safe even soon after LVAD implantation. Intrinsic myocardial scar, rather than the apical cannula, seems to be the dominant substrate.

Impella 5.0 microaxial pump as a right ventricular assist device after surgical treatment of posterior post-infarction ventricular septal defect

The Impella Recover LP 5.0 is an aortic transvalvular microaxial pump designed to unload the left ventricle and to ensure a systemic flow in severe left ventricular dysfunction. We propose a new suggestion for the Impella 5.0 as a temporary right ventricular assist device after the surgical treatment of a posterior post-infarction ventricular septal defect.

Fresh-frozen plasma transfusion did not reduce 30-day mortality in patients undergoing cardiopulmonary bypass cardiac surgery with excessive bleeding: the PLASMACARD multicenter cohort study

BACKGROUND

During on-pump cardiac surgery, hemorrhagic complications occur frequently. Fresh-frozen plasma (FFP) is widely transfused to provide coagulation factors. Yet, no randomized clinical trial has demonstrated its benefits on mortality. We assessed the relationship between therapeutic transfusion of FFP and 30-day mortality in cardiac surgery patients suffering from excessive bleeding in a prospective cohort study.

STUDY DESIGN AND METHODS

Adult patients who underwent on-pump cardiac surgery and experienced excessive bleeding during the 48-hour perioperative period were recruited from 15 French centers between February 2004 and January 2006. Patients who received a preventive FFP transfusion were excluded. The association between FFP transfusion and all cause 30-day mortality was estimated using a Cox proportional hazards model, adjusted for confounding. A propensity score (PS) sensitivity analysis was also performed.

RESULTS

Among 967 patients included in this study, 58.1% received FFP. The median dose was 11.3 mL/kg (interquartile range, 7.6-19.5). The cumulative 30-day mortality rate was 11.3% (95% confidence interval [CI], 9.5-13.5). FFP transfusion was associated with a higher 30-day mortality (hazard ratio [HR], 3.2; 95% CI, 1.7-6.1) in univariate analysis; however, after adjusting for prognostic factors, there was no longer any association (HR, 1.5; 95% CI, 0.8-3.0, p = 0.20). The results of the PS analysis were consistent with the adjusted analysis.

CONCLUSION

Among on-pump cardiac surgery patients experiencing excessive perioperative bleeding, there is no evidence of a beneficial impact of FFP transfusion on mortality.

Predicting fluid responsiveness during infrarenal aortic cross-clamping in pigs

OBJECTIVE

Infrarenal aortic cross-clamping (ACC) induces hemodynamic disturbances that may affect respiratory-induced variations in stroke volume and, therefore, affect the ability of dynamic parameters such as pulse-pressure variation (PPV) to predict fluid responsiveness. Since this issue has not been investigated yet to authors' knowledge, the hypothesis was tested that ACC may change PPV and impair its ability to predict fluid responsiveness.

DESIGN

Prospective laboratory experiment.

SETTING

A university research laboratory.

PARTICIPANTS

Nineteen anesthetized and mechanically ventilated pigs.

INTERVENTIONS

Two courses of volume expansion were performed using 500 mL of saline before and during ACC. Animals were monitored using a systemic arterial catheter, and a pulmonary arterial catheter (stroke volume, central venous pressure, pulmonary arterial occlusion pressure). Animals were defined as responders to volume expansion if stroke volume increased ≥ 15%.

RESULTS

Before ACC, 13 animals were responders. Fluid responsiveness was predicted by a PPV ≥ 14% with a sensitivity of 77% (95% CI = 46%-95%) and a specificity of 83% (95% CI = 36%-97%). The area under the receiver operating characteristic curve was 0.90(95% CI = 0.67-0.99) and was higher than those generated for central venous pressure and pulmonary arterial occlusion pressure. ACC induced an increase in PPV (p<0.0005). During ACC, 8 animals were responders. An 18% PPV threshold discriminated between responders and non-responders to volume expansion, with a sensitivity of 87% (95% CI = 47%-98%) and a specificity of 54% (95% CI = 23%-83%). The area under the receiver operating characteristic curve was 0.72 (95% CI = 0.47-0.90) and was not different from those generated for central venous pressure and pulmonary arterial occlusion pressure.

CONCLUSIONS

ACC induced a significant increase in PPV and reduced its ability to predict fluid responsiveness.

High-volume versus standard-volume haemofiltration for septic shock patients with acute kidney injury (IVOIRE study): a multicentre randomized controlled trial

PURPOSE

Septic shock is a leading cause of death among critically ill patients, in particular when complicated by acute kidney injury (AKI). Small experimental and human clinical studies have suggested that high-volume haemofiltration (HVHF) may improve haemodynamic profile and mortality. We sought to determine the impact of HVHF on 28-day mortality in critically ill patients with septic shock and AKI.

METHODS

This was a prospective, randomized, open, multicentre clinical trial conducted at 18 intensive care units in France, Belgium and the Netherlands. A total of 140 critically ill patients with septic shock and AKI for less than 24 h were enrolled from October 2005 through March 2010. Patients were randomized to either HVHF at 70 mL/kg/h or standard-volume haemofiltration (SVHF) at 35 mL/kg/h, for a 96-h period.

RESULTS

Primary endpoint was 28-day mortality. The trial was stopped prematurely after enrolment of 140 patients because of slow patient accrual and resources no longer being available. A total of 137 patients were analysed (two withdrew consent, one was excluded); 66 patients in the HVHF group and 71 in the SVHF group. Mortality at 28 days was lower than expected but not different between groups (HVHF 37.9 % vs. SVHF 40.8 %, log-rank test p = 0.94). There were no statistically significant differences in any of the secondary endpoints between treatment groups.

CONCLUSIONS

In the IVOIRE trial, there was no evidence that HVHF at 70 mL/kg/h, when compared with contemporary SVHF at 35 mL/kg/h, leads to a reduction of 28-day mortality or contributes to early improvements in haemodynamic profile or organ function. HVHF, as applied in this trial, cannot be recommended for treatment of septic shock complicated by AKI.

Hypoxia-preconditioned mesenchymal stromal cells improve cardiac function in a swine model of chronic myocardial ischaemia

OBJECTIVES

Cell loss during cardiac injection and hostility of the host-tissue microenvironment have the potential to diminish the overall effect of stem cell therapy. The purposes of this study were to evaluate the effect of a hypoxic preconditioning of mesenchymal stromal cells (MSC), to determine its safety and effectiveness, and to improve the efficacy of cell therapy using MSC in the setting of chronic myocardial ischaemia in swine.

METHODS

Myocardial ischaemia was induced by an ameroid constrictor. Human MSC were cultured under normoxic (20% O2) or hypoxic conditions (1.5% O2) before transplantation. One month after ischaemia, pigs were randomly assigned to saline injection (sham), and 1 × 10(6)/kg normoxic or hypoxic MSC transplantation into the ischaemic inferior-lateral zone.

RESULTS

Twenty-seven pigs were operated on and the mortality rate was 33.3%. The remaining 18 animals were randomly assigned to sham (n = 4), normoxic (n = 8) or hypoxic MSC (n = 6) treatment. Global systolic (left ventricle ejection fraction, P = 0.04) and diastolic (E/Ea, P = 0.008) functions were increased in the hypoxic group compared with other groups. The peak of 2-dimensional longitudinal strain was less altered in the hypoxic group compared with other groups (P < 0.001). Haemodynamic data showed that dP/dT max was improved in the hypoxic group compared with the other group (P < 0.01). Capillary density was increased in the hypoxic group (P = 0.001). MSC density was significantly higher in the ischaemic zone in the hypoxic group (P < 0.01).

CONCLUSION

MSC engraftment with hypoxic preconditioning significantly improves capillary density and cell survival, resulting in improvement in global, regional and diastolic left ventricular functions. This highlights the therapeutic potential of transplanting hypoxic-preconditioned MSC in the setting of chronic ischaemic heart failure.

Optimization of Impella 5.0 implantation using mini-sternotomy approach in postmyocardial infarction cardiogenic shock

The Impella Recover LP 5.0® (Abiomed, Inc. Danvers, MA, USA) is an aortic transvalvular microaxial pump designed to unload the left ventricle and to ensure a systemic flow in severe left ventricular dysfunction. Surgical implantation using femoral or right subclavian approach may be difficult in certain circumstances, such as encountered in peripheral vascular disease, patients with small vessels or during substantial use of vasoactive drugs responsible for vasospasm. We propose a simple and effective technique for implantation of the Impella 5.0 LVAD by means of a mini-sternotomy in patients with postinfarction refractory cardiogenic shock.

Adjustment and characterization of an original model of chronic ischemic heart failure in pig

We present and characterize an original experimental model to create a chronic ischemic heart failure in pig. Two ameroid constrictors were placed around the LAD and the circumflex artery. Two months after surgery, pigs presented a poor LV function associated with a severe mitral valve insufficiency. Echocardiography analysis showed substantial anomalies in radial and circumferential deformations, both on the anterior and lateral surface of the heart. These anomalies in function were coupled with anomalies of perfusion observed in echocardiography after injection of contrast medium. No demonstration of myocardial infarction was observed with histological analysis. Our findings suggest that we were able to create and to stabilize a chronic ischemic heart failure model in the pig. This model represents a useful tool for the development of new medical or surgical treatment in this field.

First Report of Tomato yellow leaf curl virus Infecting Tomato, Tomatillo, and Peppers in Guatemala

In Guatemala and other Central American countries, whitefly-transmitted geminiviruses (begomoviruses) cause economically important diseases of tomato (Solanum lycopersicum) and pepper (Capsicum annuum). Disease symptoms include stunted and distorted growth and leaf curling, crumpling, light green to yellow mosaic, purpling, and vein swelling. In Guatemala, at least eight bipartite begomovirus species infect tomato or peppers (1), but their role and relative importance is unclear. As part of an Integrated Pest Management strategy to manage these diseases, surveys for begomovirus symptoms in pepper and tomato have been conducted in the Salama Valley, Sanarate, and other locations since 2003, and begomoviruses were identified by squash blot hybridization, PCR and DNA sequencing. Beginning in 2006, a new type of symptom, stunted upright growth and upcurled leaves with yellowing of the margins and interveinal areas, was observed in tomato and tomatillo plants in the Salama Valley and Sanarate. These symptoms were similar to those induced by the exotic monopartite begomovirus Tomato yellow leaf curl virus (TYLCV). Evidence that TYLCV caused these symptoms came from positive results in high stringency squash blot hybridization tests with a TYLCV probe, and amplification of the expected size of ~0.3- and 2.8-kb fragments in PCR tests with TYLCV capsid protein (CP) gene and full-length component primer pairs, respectively (3). Sequence analyses of PCR-amplified CP fragments and portions of full-length fragments revealed 97 to 99% identity with isolates of TYLCV-Israel (TYLCV-IL). The complete nucleotide sequence of an isolate from the Salama Valley (GenBank Accession No. GU355941) was >99% identical to those of TYLCV-IL isolates from the Dominican Republic, Florida, and Cuba and ~97% identical to those of isolates from Mexico and California. Thus, this TYLCV-IL isolate (TYLCV-IL[GT:06]) was probably introduced from the Caribbean Region. To further characterize begomoviruses in the Salama Valley, leaf samples were collected from 44 and 118 tomato plants showing symptoms of begomovirus infection in March 2006 and 2007, respectively, and from 106 symptomatic pepper plants in March 2007. Begomovirus infection was confirmed in 42 of 44 and 93 of 118 of the tomato samples and 100 of 106 of the pepper samples based on PCR amplification of the expected size of ~0.6- and 1.1-kb DNA fragments with the begomovirus degenerate primers pairs AV494/AC1048 and PAL1v1978/PAR1c496, respectively (2,4). Sequence analyses of cloned PCR-amplified fragments revealed that 3 of the 44 and 16 of the 118 tomato samples collected in 2006 and 2007, respectively, and 9 of the 106 pepper samples were infected with TYLCV based on >97% identity with TYLCV-IL. In all samples, TYLCV was present in mixed infections with other begomoviruses. The introduction of TYLCV adds to the already high level of genetic complexity of bipartite begomovirus infection of tomatoes and peppers in Guatemala and will undoubtedly complicate disease management efforts. References: (1) M. K. Nakhla et al. Acta Hortic. 695:277, 2005. (2) M. R. Rojas et al. Plant Dis. 77:340, 1993. (3) R. Salati et al. Phytopathology 92:487, 2002. (4) S. D. Wyatt and J. Brown. Phytopathology 86:1288, 1996.

Evaluation of continuous veno-venous hemofiltration for the treatment of cardiogenic shock in conjunction with acute renal failure after cardiac surgery

BACKGROUND

Cardiogenic dysfunction with acute renal failure (ARF) and diuretic drug resistance increases mortality after cardiac surgery with cardiopulmonary bypass (CPB) in adults. Until few years ago, intermittent renal replacement therapy (IRRT) was the only therapeutical strategy proposed to such patients. Few data are available in the literature regarding the use of continuous veno-venous haemofiltration (CVVH) in this clinical context. The aim of our observational study was to evaluate the impact of CVVH strategy on ARF in conjunction with cardiogenic shock after cardiac surgery and on its well-known associated poor outcome.

METHODS

During the period 2005-2006, we prospectively collected data from our database as we controlled the renal replacement therapy using CVVH (n=73). We also retrospectively collected data from our computerised database on patients who were treated with IRRT (n=68, period 2002-2003). Among CVVH-treated patients, a multivariate analysis of the data aimed to identify risk factors associated with 30-day mortality.

RESULTS

In patients who presented with ARF in conjunction with cardiogenic shock after cardiac surgery, 30-day mortality rate was 59% for the IRRT group and 42% for the CVVH group. Within the CVVH group, the logistic regression and multivariate analyses reported that some variables were associated with higher mortality risk: a score F concerning the urinary output criteria of the RIFLE (risk, injury, failure, loss, end-stage kidney disease) classification (for scores R or I: odds ratio (OR): 0.01, 95% confidence interval (95% CI): 0.02-0.59; p=0.01), plasma bilirubin (OR: 1.44, 95% CI: 1.12-1.84; p=0.04), total CVVH duration <50h over 72 h (>50h; OR: 0.009, 95% CI: 0.04-0.93; p=0.01), the need of catecholamine support (OR: 12.88, 95% CI: 1.95-84.96; p=0.01), tachycardia in the intensive care unit (ICU; OR: 1.64, 95% CI: 1.02-2.65; p=0.04), surgery duration (<300 min; OR: 0.11, 95% CI: 0.02-0.71; p=0.02) and combined cardiac surgery (OR: 7.00, 95% CI: 1.29-37.88; p=0.02).

CONCLUSION

In patients with ARF in conjunction with cardiogenic shock after cardiac surgery, renal replacement therapeutic strategy based on long-lasting CVVH could improve patients' outcome. The identification of risk factors associated with a poor outcome would help to better manage such patients in the ICU. Low total duration of CVVH within the first 72 h was one criteria related to poor outcome. This suggests that CVVH must be initiated as soon as possible when ARF with diuretic resistance occurs in patients after cardiac surgery and continued as long as possible for the first 3 days.

Assessing cardiovascular risk factors after coronary artery bypass surgery: value of an aggressive strategy including systematic follow-up

INTRODUCTION

Coronary revascularization surgery is a palliative treatment modality which should not preclude efforts to treat atherosclerosis.

AIM

To assess ongoing cardiovascular risk factors after coronary artery bypass surgery and develop a strategy to attenuate such factors.

METHODS

108 patients requiring a coronary artery bypass were included: 2 died soon after surgery and 6 were excluded for personal reasons. 100 patients were re-admitted into hospital 7 months after surgery for risk factor assessment. Eight months later, they were re-contacted by telephone (systematic follow-up) for a re-assessment.

RESULTS

The population consisted of 77 men with an average age of 64+/-11 years. Prior to the operation, the known risk factors were: smoking 34%; HBP 61%; cholesterol 47%; diabetes 30%; obesity 25%. During their hospital stay six months after the procedure: 91% of the patients had at least one lipid metabolism abnormality. New-onset diabetes was diagnosed in 5%. Blood pressure was uncontrolled in 18% and 10% were still smoking. Patients tended to be putting on weight and 55% engaged in little or no physical activity. Systematic follow-up: lipid metabolism had normalized in 70% of the patients. Blood glucose levels were significantly lower. Blood pressure was uncontrolled in 9% and 4% were still smoking. Their weight had stabilized and 65% were engaging in moderate-to-strenuous physical activity.

CONCLUSION

Inadequate attention is paid to risk factors after coronary artery bypass surgery. A short hospital stay including a cardiovascular evaluation and education about risk factors has a positive impact on the management of atherosclerosis in the medium term.

Off-pump coronary artery bypass surgery in very high-risk patients: adjustment and preliminary results

Left ventricle dysfunction and comorbidities are responsible for a large number of complications after CABG. OPCAB could be an interesting alternative for very high-risk patients. Patients were included if EuroSCORE >9, or with at least two of the following criteria, severe LV dysfunction, recent myocardial infarction (MI), terminal renal failure, lung dysfunction, PVD, BMI>30. Patients were operated using the Octopus (Medtronic) system. One hundred and twenty patients, mean age 68+/-10 years, 72% male, were operated. Mean EuroSCORE was 10.2+/-5.3, LV function 36.79+/-11.3%, recent MI 57%, renal failure 52%, COPD 44%, PVD 52%, obesity 34%. Mean graft per patient was 2.1+/-0.8. Three patients underwent secondary PTCA treatment for incomplete revascularization. Combined surgery was required for 20%. Early mortality was 3%. Intensive care unit stay was 2.7 days. Early complications were: low output syndrome 3%, MI 0.8%, stroke 0.8%, kidney support 7%. Graft patency was systematically analyzed with MCTA or angiocardiography. OPCAB strategy seems to be safe and secure in this population of very high-risk patients reducing multi-organ failure. However, long-term results are needed to confirm this strategy.

Validation of a continuous, arterial pressure-based cardiac output measurement: a multicenter, prospective clinical trial

Introduction

The present study compared measurements of cardiac output by an arterial pressure-based cardiac output (APCO) analysis method with measurement by intermittent thermodilution cardiac output (ICO) via pulmonary artery catheter in a clinical setting.

Methods

The multicenter, prospective clinical investigation enrolled patients with a clinical indication for cardiac output monitoring requiring pulmonary artery and radial artery catheters at two hospitals in the United States, one hospital in France, and one hospital in Belgium. In 84 patients (69 surgical patients), the cardiac output was measured by analysis of the arterial pulse using APCO and was measured via pulmonary artery catheter by ICO; to establish a reference comparison, the cardiac output was measured by continuous cardiac output (CCO). Data were collected continuously by the APCO and CCO technologies, and at least every 4 hours by ICO. No clinical interventions were made as part of the study.

Results

For APCO compared with ICO, the bias was 0.20 l/min, the precision was ± 1.28 l/min, and the limits of agreement were -2.36 l/m to 2.75 l/m. For CCO compared with ICO, the bias was 0.66 l/min, the precision was ± 1.05 l/min, and the limits of agreement were -1.43 l/m to 2.76 l/m. The ability of APCO and CCO to assess changes in cardiac output was compared with that of ICO. In 96% of comparisons, APCO tracked the change in cardiac output in the same direction as ICO. The magnitude of change was comparable 59% of the time. For CCO, 95% of comparisons were in the same direction, with 58% of those changes being of similar magnitude.

Conclusion

In critically ill patients in the intensive care unit, continuous measurement of cardiac output using either APCO or CCO is comparable with ICO. Further study in more homogeneous populations may refine specific situations where APCO reliability is strongest.

[Perioperative anticoagulation management for prosthetic heart valves]

OBJECTIVES

The practices and the guidelines over the perioperative management of the anticoagulation of patients with cardiac valves prothesis are the object of no consensual attitude. The thrombotic risk over the time is well known. It depends of the type or the location on the valve, of their associations and the age of the patient. In the perioperative period, the antithrombotic treatment must be interrupted according to the surgical haemorrhagic risk.

STUDY DESIGN

Short review.

RESULTS

Only patients, without associated risk factor, carriers of bioprosthesis from more than 3 months, can be maintained only under antiplatelets agents. In others situations, the caution imposes a bridge of anticoagulants from 48 to 72 hours with unfractionated heparin (subcutaneous at home, intravenous at the hospital). Low molecular weight heparin has no commercial authorization in this indication. The resumption of the anticoagulation by unfractionated heparin in postoperative period must be the most premature possible after the decrease of the surgical bleeding. The relay by vitamin K antagonists has to be made over 48 to 72 hours. Within the framework of the urgency, the surgical haemorrhagic risk is weak for an INR <1.5. According to the urgency of the surgery, a treatment by vitamin K (if the delay is over 12 hours) or by prothrombinic complex allows to correct this INR. The identification of thrombotic complications requires a particular attention. In the postoperative period, as soon as there is suspicion of thrombosis, clinical manifestations must be consolidated by the practice of a transoesophageal echography, which only confirm the diagnosis.

Phylogenetic relationships within the Mysidae (Crustacea, Peracarida, Mysida) based on nuclear 18S ribosomal RNA sequences

Species of the order Mysida (Crustacea, Peracarida) are shrimp-like animals that occur in vast numbers in coastal regions of the world. The order Mysida comprises 1,053 species and 165 genera. The present study covers 25 species of the well-defined Mysidae, the most speciose family within the order Mysida. 18S rRNA sequence analysis confirms that the subfamily Siriellinae is monophyletic. On the other hand the subfamily Gastrosaccinae is paraphyletic and the subfamily Mysinae, represented in this study by the tribes Mysini and Leptomysini, consistently resolves into three independent clades, and hence is clearly not monophyletic. The tribe Mysini is not monophyletic either, and forms two clades of which one appears to be closely related to the Leptomysini. Our results are concordant with a number of morphological differences urging a taxonomic revision of the Mysidae.

Dextran sulfate included in factor Xa assay reagent overestimates heparin activity in patients after heparin reversal by protamine

A lack of correlation between activated partial thromboplastin time (aPTT), thrombin time (TT) and anti-factor Xa (AXa) activity was observed in patients after cardiac surgery with cardiopulmonary bypass (CBP). Indeed, AXa activity measured by the chromogenic assay, Coamatic Heparin, was higher than expected with regard to results obtained in coagulation assays. To account for this discrepancy, another AXa chromogenic assay was tested. First, AXa activity was measured with two chromogenic assays (Coamatic Heparin and Rotachrom Heparin) in plasma samples of 25 patients undergoing cardiac surgery at two time points after heparin reversal by protamine. AXa activity was significantly higher when measured with Coamatic Heparin than with Rotachrom Heparin in samples collected just after protamine infusion (p<0.01). Next, since Coamatic( Heparin contains dextran sulfate (DXS) to reduce the influence of heparin antagonists such as platelet factor 4 (PF4), whereas Rotachrom Heparin does not, we hypothesized that the dextran sulfate contained in the reagent might explain this discrepancy. We therefore performed in vitro studies consisting in neutralizing unfractionated heparin (UFH) with protamine and measuring AXa activity with the two chromogenic assays. An AXa activity was still measurable with Coamatic Heparin after neutralization, thus strongly suggesting that dextran sulfate dissociates protamine/heparin complexes. We conclude that Coamatic Heparin assays should be avoided when measuring AXa activity in plasma samples immediately after protamine infusion, as inaccurate results may lead to inadequate management of heparin reversal.

Isolation, identification, and synthesis of a disulfated sulfakinin from the central nervous system of an arthropods the white shrimp Litopenaeus vannamei

Two myotropic peptides displaying tyrosyl sulfation have been isolated from an extract of central nervous systems (brain, suboesophageal ganglion, thoracic ganglia, and ventral nerve cord) of the white shrimp Litopenaeus vannamei. Both peptides were identified by mass spectrometry and belong to the sulfakinin family of neuropeptides, which are characterized by the C-terminal hexapeptide Y(SO(3)H)GHMRF-NH(2) preceded by two acidic amino acid residues. Pev-SK 1 (AGGSGGVGGEY(SO(3)H)DDY(SO(3)H)GH(L/I) RF-NH(2)) has two sulfated tyrosyl residues and a unique (L/I) for M substitution in the C-terminal sequence. Pev-SK 2 (pQFDEY(SO(3)H)GHMRF-NH(2)) fully complies with the typical sulfakinin core sequence and is blocked by a pyroglutamyl residue. Synthetic analogs (sulfated and unsulfated) were synthesized and the tyrosyl sulfations were confirmed by myotropic activity studies and co-elution with the native fractions. Pev-SK 1 is the first disulfated neuropeptide elucidated in the phylum of the arthropoda, with the only other reported disulfated neuropeptide, called cionin, found in a protochordate. The similarities in amino acid sequence and posttranslational modifications of the crustacean sulfakinins and protochordate cionin provide further evidence for the hypothesis stating that gastrin/CCK, cionin, and sulfakinins originate from a common ancestral gastrin/CCK-like peptide.

[Training for adult subclavian venous catheterization: use of real-time echography]

OBJECTIVE

To assess the training in adult subclavian venous catheterization of an inexperienced operator, with two different procedures: ultrasound guidance vs anatomic landmark technique.

STUDY DESIGN

Prospective, comparative study.

PATIENTS AND METHODS

After informed consent, 50 adults were divided in two groups, with an original method of inclusion, designed to assess the training of the operator, which alternated ultrasound guidance (n = 25) and Aubaniac's landmark technique (n = 25).

RESULTS

All the catheterizations have been completed. The success rate at first attempt was higher in ultrasound group than in landmark group, without reaching significance (76 vs 56%). Two arterial punctures were reported in landmark group. With ultrasound guidance, there were 21 puncture sites at the external third and 4 at the medial third of the clavicle. Average access time (skin to vein) was 15 +/- 8 seconds in ultrasound group and 63 +/- 78 seconds in landmark group (p < 0.01), with a significant relation between access time and patient rank in landmark group (r2 = 0.42, p < 0.01).

CONCLUSION

Ultrasound guidance makes the training in adult subclavian venous catheterization easier, and allows inexperimented operator to be rapidly efficient. The use of ultrasound would decrease the incidence of complications by a real time visualization of anatomical structures, and by a more external approach of the vein than in the Aubaniac's technique.

Soluble minerals in chemical evolution. I. Adsorption of 5'-AMP on CaSO4--a model system

The adsorption of 5'-AMP onto solid CaSO4 2H2O was studied in a saturated suspension as a function of pH and electrolyte concentration. The adsorption is pH-dependent and is directly correlated with the charge on the 5'-AMP molecule which is determined by the state of protonation of the N-1 nitrogen of the purine ring and the phosphate oxygens. It is proposed that the binding occurs between the nucleotide and the salt is electrostatic in nature. The adsorption decreases with increasing ionic strength of the solution which means that in a fluctuating environment of wetting and drying cycles, a biomolecule similar to 5'-AMP could be expected to desorb during the drying phase. The results indicate that CaSO4 2H2O can serve as a concentrating surface for biomolecules. The significance of this is discussed with regard to the possible role of soluble minerals and their surfaces in a geochemical model consistent with the evolution of the Earth and the origin of life.

Perception, attention, and working memory are disproportionately impaired in dementia with Lewy bodies compared with Alzheimer's disease

OBJECTIVE

To test the hypotheses that visuoperceptual and attentional ability are disproportionately impaired in patients having dementia with Lewy Bodies (DLB) compared with Alzheimer's disease (AD).

METHODS

A comprehensive battery of neuropsychological tasks designed to assess working, episodic, and semantic memory, and visuoperceptual and attentional functions was given to groups of patients with DLB (n=10) and AD (n=9), matched for age, education, and mini mental state examination (MMSE), and to normal controls (n=17).

RESULTS

Both patient groups performed equally poorly on tests of episodic and semantic memory with the exception of immediate and delayed story recall, which was worse in the AD group. Digit span was by contrast spared in AD. The most striking differences were on tests of visuoperceptual/spatial ability and attention. Whereas patients with AD performed normally on several subtests of the visual object and space perception battery, the DLB group showed substantial impairments. In keeping with previous studies, the AD group showed deficits in selective attention and set shifting, but patients with DLB were more impaired on virtually every test of attention with deficits in sustained, selective, and divided attention.

CONCLUSIONS

Patients with DLB have substantially greater impairment of attention, working memory, and visuoperceptual ability than patients with AD matched for overall dementia severity. Semantic memory seems to be equally affected in DLB and AD, unlike episodic memory, which is worse in AD. These findings may have relevance for our understanding of the genesis of visual hallucinations, and the differential diagnosis of AD and DLB.

Pulsed plasma deposition of allylamine on polysiloxane: a stable surface for neuronal cell adhesion

Allylamine was pulse-plasma polymerized onto a hydrophobic polysiloxane substrate to create cell adhesion surfaces for cell culture that would not require pretreatment with polylysine, could be sterilized via autoclaving, and could be re-used for several culture cycles. We investigated two different plasma deposition protocols at 200 W RF power: (1) a duty cycle of 3 ms on and 5 ms off; and (2) a cycle of 3 ms on and 45 ms off. Control surfaces were unmodified polysiloxane, activated polysiloxane via flaming, and flamed polysiloxane further modified with poly-D-lysine (PDL). The different surfaces were characterized with XPS analysis, water contact angle, and cell adhesion and growth using dissociated murine embryonic spinal tissue. We found that both the amine content of the 3/45 duty cycle surface and the wettability was higher than that of the 3/5 surface. Also, spinal cord cells were better dispersed 24 h after seeding on the 3/45 surface, suggesting a difference in early adhesion dynamics. However, the networks on the two types of modified surfaces revealed no obvious morphological differences after 2 weeks in vitro. The stability of allylamine-decorated surfaces after autoclaving was high with only minor changes in wettability and nitrogen content. Cell growth on such surfaces after autoclaving was comparable to that found on flamed polysiloxane, freshly modified with PDL. Allylamine surfaces were still usable as cell growth substrates after three autoclaving cycles, 4 weeks under warm culture medium, and simple cleaning procedures, indicating the achievement of a long-lasting modification that did not require the repeated use of PDL before each seeding.

Potential use of ipatropium bromide for the treatment of clozapine-induced hypersalivation: a preliminary report

Sialorrhea is reported by 31% of patients taking clozapine. Anticholinergic agents and adrenergic agonists are used for its treatment based on empirical evidence. In the present study, 10 patients who failed to respond to anticholinergic or adrenergic agents received intranasal ipatropium bromide (IPB) to minimize anticholinergic systemic absorption. Intranasal IPB was given to 10 patients for clozapine-induced sialorrhea who failed to respond to benztropine or clonidine. Pre-, post- and 6 month follow-up values were recorded on a single-item, 5-point Hypersalivation Rating Scale. The sign test was used for statistical comparison (P < 0.05). Eight patient reported initial improvement in sialorrhea values. Two patients reported no change and two patients discontinued IPB. At 6 months, six patients maintained improvement. Side-effects for IPB were minor. A significant trend was observed in the values pre- and post-treatment with IPB (P < 0.004). Improvement was maintained at 6 month follow-up (P < 0.008). This case series demonstrates the possible utility of intranasal IPB for clozapine-induced sialorrhea. Intranasal IPB lacks significant systemic anticholinergic effects when prescribed along with clozapine. This study shows only qualitative differences in salivation values and large controlled-comparative trials are needed.

First Report of Golden Dwarf Mistletoe on Pinus maximinoi

Golden dwarf mistletoe (Arceuthobium aureum subsp. aureum Hawksw. & Wiens) is endemic to east-central Guatemala (Departments Alta Verapaz, Baja Verapaz, and Quiche) (1,2). Its principal hosts are Pinus pseudostrobus Lindl., P. montezumae Lamb., and P. oaxacana Mirov (1). In May 1999, A. aureum subsp. aureum was observed infecting Pinus maximinoi H. E. Moore at four locations: 1.0 km south (altitude 1,580 m) and 5.4 km north (altitude >1,630 m) of La Cumbre, Baja Verapaz on Route CA-14, 8 km west (altitude 1,670 m) of Chilasco, Baja Verapaz, and 5 km west (altitude 1,490 m) of San Cristobal Verapaz, Alta Verapaz on Route 7-W. Although previous reports (1,2) indicated that golden dwarf mistletoe does not induce witches'-brooms on its hosts, older (>50 years), severely affected P. maximinoi were observed to have formed large witches'-brooms as a result of dwarf mistletoe infection. Although it has been suggested that Pinus oocarpa Schiede is susceptible to golden dwarf mistletoe (1), several large trees of this species were observed growing within 5 m of infected P. maximinoi at three of the four locations, but none were infected. This is the first report of golden dwarf mistletoe on P. maximinoi. References: (1) F. G. Hawksworth and D. Wiens. 1996. Dwarf Mistletoes: Biology, Pathology, and Systematics. USDA Agric. Handb. 709. (2) D. Wiens and C. G. Shaw, J. Idaho Acad. Sci. 30:25, 1994.

Vibrios associated with Litopenaeus vannamei larvae, postlarvae, broodstock, and hatchery probionts

Several bacteriological surveys were performed from 1994 to 1996 at different Litopenaeus vannamei hatcheries (in Ecuador) and shrimp farms (in Mexico). Samples were taken from routine productions of healthy and diseased L. vannamei larvae, postlarvae, and their culture environment and from healthy and diseased juveniles and broodstock. In Ecuador, the dominant bacterial flora associated with shrimp larvae showing symptoms of zoea 2 syndrome, mysis mold syndrome, and bolitas syndrome has been determined. Strains were characterized by Biolog metabolic fingerprinting and identified by comparison to a database of 850 Vibrio type and reference strains. A selection of strains was further genotypically fine typed by AFLP. Vibrio alginolyticus is predominantly present in all larval stages and is associated with healthy nauplius and zoea stages. AFLP genetic fingerprinting shows high genetic heterogeneity among V. alginolyticus strains, and the results suggest that putative probiotic and pathogenic strains each have specific genotypes. V. alginolyticus was found to be associated with larvae with the zoea 2 syndrome and the mysis mold syndrome, while different Vibrio species (V. alginolyticus and V. harveyi) are associated with the bolitas syndrome. V. harveyi is associated with diseased postlarvae, juveniles, and broodstock. The identities of the strains identified as V. harveyi by the Biolog system could not be unambiguously confirmed by AFLP genomic fingerprinting. Vibrio strain STD3-988 and one unidentified strain (STD3-959) are suspected pathogens of only juvenile and adult stages. V. parahaemolyticus, Photobacterium damselae, and V. mimicus are associated with juvenile and adult stages.

The behaviour of titanium as a biomaterial: microscopy study of plates and surrounding tissues in facial osteosynthesis

Titanium has become the biomaterial of choice for facial osteosynthesis. Titanium is considered a highly biocompatible and corrosion resistant material, although the ultrastructural behaviour of titanium in human tissues after bone fixation is not well documented. A prospective scanning electron microscopy study was carried out on 37 commercially pure titanium miniplates which were removed from 23 patients who had undergone surgery for maxillofacial trauma or deformity. Twenty two cases were used as a control group. Implant-bone specimens were excised using tungsten burs and studied with a scanning electron microscope (Jeol JSM-T-300). Findings at the bone-titanium interface were analyzed, as well as the presence of contaminating bodies on the specimen surface. Biopsies were also obtained from the soft tissues adjacent to 20 miniplates, then sectioned and stained with Haematoxilin-Eosin for histological evaluation by light microscopy. The results showed good ultrastructural osseointegration of the osteosynthesis material in most cases (81.8%). Mobility was found upon removal in 80% of plates which showed clinical complications. A significant correlation was found between the degree of microscopical osseointegration and macroscopic fixation of the plate. Microscopical contamination was found in 100% of the nine plates with intraoral exposure, while only 36% of the 22 miniplates of the control group had contaminating elements (P < 0.001). Thirty-five point one percent of the plates showed hole-like substance loss images, whose size ranged from 10-25 mu. Light microscopy showed granular deposits in soft tissues surrounding the plates in 80% of the 20 specimens investigated. Our findings suggest a higher development of corrosion in titanium than previously reported. These findings are not correlated, however with the clinical complications.

Identification of one tachykinin- and two kinin-related peptides in the brain of the white shrimp, Penaeus vannamei

This paper reports the purification of three myotropic neuropeptides from the white shrimp Penaeus vannamei. The central nervous systems of 3500 shrimps were extracted in an acidified solvent, after which four to five HPLC column systems were used to obtain pure peptides. A cockroach hindgut muscle contraction bioassay was used to monitor all collected fractions. The pure peptides were submitted to Edman degradation based automated microsequencing. Mass spectrometry and chemical synthesis confirmed the sequences. Ala-Pro-Ser-Gly-Phe-Leu-Gly-Met-Arg-NH2 (Pev-tachykinin, 934.1 Da) belongs to the tachykinin family with identified members in all vertebrate classes and some invertebrate classes: arthropods, annelids and molluscs. A very specific Pev-tachykinin antiserum was developed, which labels 4 neurosecretory cells in the brain. Ala-Ser-Phe-Ser-Pro-Trp-Gly-NH2 (Pev-kinin 1, 749.8 Da) and Asp-Phe-Ser-Ala-Trp-Ala-NH2 (Pev-kinin 2, 694.7 Da) are the first crustacean kinins. Pev-kinin 2 is the first kinin with a Trp-Ala-NH2 instead of a kinin-typical Trp-Gly-NH2 carboxyterminus.

Role of neutrophils in innate resistance to Entamoeba histolytica liver infection in mice

In order to define the role of neutrophils in the innate resistance to Entamoeba histolytica liver infection in mice, we examined the pattern of liver lesion induced by direct injection of E. histolytica trophzoites in normal mice and in neutrophil-depleted mice. A variety of histological lesions were found, the extent of liver damage was considerably higher in the neutrophil-depleted mice. Livers from neutrophil-depleted mice displayed areas of liquefactive (lytic) necrosis containing a large number of amoebae and absence of neutrophils or mononuclear cells. By contrast, in the liver of normal mice, neutrophils were seen associated to E. histolytica at early stages of infection. In both mouse groups, areas of TUNEL-positive dead hepatocytes were observed and a characteristic internucleosomal banding pattern of genomic DNA consistent with apoptosis was detected in DNA harvested from amoebic liver lesions. These data suggest that neutrophils play an important role in the mechanisms of resistance to amoebic liver infection in mice. In addition, our histological analysis suggests that E. histolytica is capable of producing liver damage in the absence of inflammatory cells.

Short report: identification of B-cell epitopes in the serine-rich Entamoeba histolytica protein

The serine-rich Entamoeba histolytica protein (SREHP) has been shown to be a protective antigen in animal models of amebic liver abscess when delivered by either parenteral or oral routes of immunization, and antibodies to SREHP can prevent amebic liver abscess in severe combined immunodeficient mice. To identify B cell epitopes of the SREHP molecule that could serve as the basis for a peptide-based vaccine, we synthesized overlapping peptides spanning the amino acid sequence of SREHP, and looked at the reactivity of serum samples from five individuals with amebic liver abscess to the overlapping peptides. We found that most of the epitopes recognized by serum samples from patients with amebic liver abscess map to the hydrophilic dodecapeptide or octapeptide repeats of SREHP, but there was no universal epitope recognized by all five serum samples. In addition, we show that synthetic peptides that include the epitopes of SREHP recognized in the mapping study are immunogenic in animals and can generate antibodies that recognize SREHP.