First medical contact facility type as a determinant of prognosis in a regional ST elevation myocardial infarction network

Background

Delay in primary percutaneous coronary intervention (PPCI) in ST elevation myocardial infartion (STEMI) is associated with worse prognosis. In our regional STEMI network, the first medical contact (FMC) facility type defines 4 different assistance pathways (i.e. emergency medical services'diagnosis on the field and direct transfer to the catheterization laboratory (cath. lab) of a PCI hospital (EMS group); direct admission to a PCI hospital (PCI-H group); admission to community hospital and transfer to the cath lab of the PCI-H (CH group); diagnosis in a primary care centre and transfer to the cath lab of the PCI-H (PCC group). Each different FMC has been associated with different degrees in reperfusion delay.

Objective

To determine the influence of FMC facility type on 1-year mortality in patients with STEMI in our regional STEMI network.

Methods

This is a retrospective study based on the STEMI network registry, a mandatory registry conducted since its implantation and supervised by the regional health authorities. We included STEMI patients treated with PPCI from January 2010 to December 2020. We analyzed differences in clinical variables, reprefusion times and 1-year all-cause mortality regarding the FMC facility type.

Results

We included 18332 patients (EMS 34.25%, PCI-H 12.28%, CH 33.47%, PCC 20.01%). Initial Killip classes III–IV: EMS 8.43%, PCI-H 7.51%, CH 5.54%, PCC 3.76%; p<0.001. All comorbidities and complications in first medical assistance were more frequent in EMS and PCI-H groups (p<0.05). PCC group had the lowest risk profile regarding comorbidities and first medical assistance complications (p<0.05 for most of variables). The PCI-H group had the shortest system delay (median 82 min, p<0.001), the EMS group had the shortest total ischemic time (median 151 min, p<0.001). Crude 1-year mortality was EMS 8.6%, PCI-H 9.11%, CH 8.25%, and PCC 4.77% (p<0.001). After adjusting for several covariables with a logistic regression model, PCI-H and CH groups were associated with higher 1-year mortality compared to EMS group (OR 1.23 (IC95% 1.01–1.49; p=0.04) and OR 1.16 (IC95% 1.01–1.34; p=0.04) respectively), while PCC group was associated with lower 1-year mortality (OR 0.69 (IC95% 0.57–0.84; p<0.01)).

Conclusions

First medical contact with EMS and direct transfer to the cath lab was associated with lower adjusted 1-year mortality compared to first medical contact with a PCI hospital or a community hospital.

Funding Acknowledgement

Type of funding sources: None.

Impact of COVID-19 on mechanical complications in ST elevation myocardial infarction

Background

Mechanical complications (MC) give a poor prognosis for ST elevation myocardial infarction (STEMI). Its prevalence had decreased in the era of primary angioplasty, at the expense of free wall rupture (FWR).

Purpose

To analyse the prevalence of post-STEMI MC for two periods, before and after the COVID-19 pandemic.

Methods

Unicentric prospective registration of patients with STEMI admitted between January-2018 and December-2021. They are classified into two groups according to the onset of the pandemic by COVID-19: Pre-COVID: January-2018 to December-2019, and Post-COVID: January-2020 to December-2021. The prevalence of post-STEMI MC is analysed, including ventricular septal rupture (VSR), papillary muscle rupture (PMR) and FWR, and 30-day mortality.

Results

1507 consecutive patients with STEMI (Pre-COVID n=775, Post-COVID n=732) are included. Age 62.9 years vs 63.3 years (p=0.5097). Men 78.1% Vs 79.5% (p=0.493). No differences in cardiovascular risk factors, previous heart infarction or anterior wall STEMI. Primary angioplasty was similar in both groups (92%). The Post-COVID group has a higher prevalence of Killip>I (21.7% vs 17.2% p=0.025) and LVEF ≤40% (27.2% vs 20% p=0.001), and longer symptom onset to balloon dilatation interval (316 min vs 257 min p=0.0004). MC are most developed in Post-COVID (2.6% vs 1.2% p=0.039), at the expense of FWR (1.91% vs 0.3% p=0.001). No significant changes in VSR and PMR prevalence or 30-day mortality. Multivariate analysis identifies the independent predictors of FWR: Age (OR 1.05, p=0.024), Primary angioplasty (OR 0.09, p<0.001), and Post-COVID (OR 6.8, p=0.013).

Conclusions

The COVID-19 pandemic is independently associated with a higher prevalence of FWR, probably due to delayed reperfusion.

Funding Acknowledgement

Type of funding sources: None.

Mortality risk in cardiogenic shock depending on aetiology in a Mediterranean cohort. Prognostic accuracy of CardShock vs IABP score: the Shock CAT study

Background

Mortality in cardiogenic shock (CS) remains very high. Several risk scores have been purposed to early stratification, although the CS aetiology could influence in this prediction.

Purpose

The aim is to investigate in-hospital prognosis and mortality risk in CS patients depending on the CS aetiology comparing the prognostic accuracy of CardShock and IABP scores in a Mediterranean cohort.

Method

Shock CAT study was a multicentre, prospective, observational study conducted between December 2018 and December 2019 in eight public University hospitals in Catalonia (Spain), including CS patients due to acute coronary syndrome (ACS) and other aetiologies. Data on clinical presentation, biomarkers, management, including mechanical assistance support were analyzed comparing ACS and non-ACS patients. Cardshock and IABP score have been compared to assess 90-days mortality risk in both groups.

Results

A total of 382 CS patients were included, mean age was 65.3 (SD 13.9) years and 75.1% were men. Patient were classified in ACS (n=232, 60.7%) and non-ACS (n=150, 39.3%). In ACS group, 77.6% were STEMI, reperfussion in 84.7% of cases, all with primary angioplasty, 9% developed mechanical complications and 19.4% primary ventricular fibrillation. Main non-ACS aetiologies were severe heart failure (36.2%), malignant arrhythmias (22.1%), valve disease (8.0%) and myocarditis (7.4%). ACS group had less prevalence of women (17.7% vs 36%, p=0.001) and previous myocardial infarction (13.9% vs 24.8%, p=0.007). Mechanical assistance device was implanted more in ACS patients (43.1% vs 16.7%, p&lt;0.001, mainly intraaortic balloon pump (35.6% vs 9.8%, p&lt;0.001) and ECMO (10.7% vs 3%, p=0.01). Both shock risk scores were higher in ACS patients, Cardshock (4.5 vs 4.0, p=0.006) and IABP (2.4 vs 1.9, p=0.005). In-hospital mortality was higher in ACS (37.1 vs 26.7%, p=0.035) although this difference loss the significance at 90-days (40.9 vs 31.8%, p=0.074) and 6-months (45.2 vs 35.8%, p=0.176). Receiver-operating characteristic curves demonstrated that IABP shock score had superior prognostic power for predicting 90-days mortality when compared with Cardshock score in ACS patients (area under the curve -AUC- 0.74 vs 0.66) respectively, p=0.047, although both scores were similar in non-ACS (AUC 0.64 vs 0.62, p=0.693), Figures 1–2.

Conclusions

Cardiogenic shock due to ACS had higher in-hospital mortality than non-ACS CS, although this difference decreased at 90 days and 6 months. IABP score provided better 90-days mortality risk prediction than CardShock score in ACS patients, but both scores are similar in non-ACS cardiogenic shock.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Mortality risk in cardiogenic shock: head to head comparision CardShock vs IABP score in a Mediterranean cohort: the Shock CAT study

Background

Mortality in cardiogenic shock (CS) remains very high. Several risk scores have been purposed to early stratification.

Purpose

The aim is to investigate in-hospital prognosis and mortality risk in CS patients comparing the prognostic accuracy of CardShock and IABP scores in a Mediterranean cohort.

Method

Shock CAT study was a multicentre, prospective, observational study conducted between December 2018 and December 2019 in eight public University hospitals in Catalonia (Spain), including CS patients due to acute coronary syndrome (ACS) and other aetiologies. Data on clinical presentation, biomarkers, management, including mechanical assistance support were analyzed. Cardshock and IABP score have been compared to assess 90-days mortality risk in a Mediterranean cohort.

Results

A total of 382 CS patients were included, mean age was 65.3 (SD 13.9) years and 75.1% were men. The most common cause of CS was ACS (61%, n=233); of them, 77.6% were STEMI, 9% developed mechanical complications and 19.4% primary ventricular fibrillation. STEMI patients were reperfused in 84.7% of cases, all with primary angioplasty. Main non-ACS aetiologies were severe acute heart failure, malignant arrhythmias and myocarditis. Mechanical assistance device was implanted in one third of patients (n=119), mainly intraaortic balloon pump (26.1%), ECMO in 7.8% and Impella in 4.5%. Average Cardshock score was 4.3 (SD 1.74) and mean IABP score was 2.2 (SD 1.61). In-hospital mortality was 33% (126 patients) and 90-days mortality was 37.3% (141 patients). Receiver-operating characteristic curves demonstrated that IABP shock score had superior prognostic power for predicting 90-days mortality when compared with Cardshock score (area under the curve 0.72 vs 0.66) respectively, p=0.042; Figure 1.

Conclusions

Even though invasive management with STEMI reperfusion and mechanical assistance devices, cardiogenic shock in-hospital mortality remains 33% in a contemporary Mediterranean cohort. In this population, IABP shock score provided better 90-days mortality risk prediction than CardShock score

Funding Acknowledgement

Type of funding sources: None.

Growth differentiation factor-15 is a predictive biomarker in primary ventricular fibrillation: The RUTI-STEMI-PVF study

Background:

Primary ventricular fibrillation is an ominous complication of ST-segment elevation myocardial infarction, and proper biomarkers for risk prediction are lacking. Growth differentiation factor-15 is a marker of inflammation, oxidative stress and hypoxia with well-established prognostic value in ST-segment elevation myocardial infarction patients. We explored the predictive value of growth differentiation factor-15 in a subgroup of ST-segment elevation myocardial infarction patients with primary ventricular fibrillation.

Methods:

Prospective registry of ST-segment elevation myocardial infarction patients treated with primary percutaneous coronary intervention from February 2011–August 2015. Growth differentiation factor-15 concentrations were measured on admission. Logistic regression and Cox proportional regression analyses were used.

Results:

A total of 1165 ST-segment elevation myocardial infarction patients treated with primary percutaneous coronary intervention (men 78.5%, age 62.3±13.1 years) and 72 patients with primary ventricular fibrillation (6.2%) were included. Compared to patients without primary ventricular fibrillation, median growth differentiation factor-15 concentration was two-fold higher in ST-segment elevation myocardial infarction patients with primary ventricular fibrillation (2655 vs 1367 pg/ml, p&lt;0.001). At 30 days, mortality was 13.9% and 3.6% in patients with and without primary ventricular fibrillation, respectively (p&lt;0.001), and median growth differentiation factor-15 concentration in patients with primary ventricular fibrillation was five-fold higher among those who died vs survivors (13,098 vs 2415 pg/ml, p&lt;0.001). In a comprehensive multivariable analysis including age, sex, clinical variables, reperfusion time, left ventricular ejection fraction, N-terminal pro-B-type natriuretic peptide and high-sensitivity troponin T, growth differentiation factor-15 remained an independent predictor of 30-day mortality, with odds ratios of 3.92 (95% confidence interval 1.35–11.39) in patients with primary ventricular fibrillation (p=0.012) and 1.72 (95% confidence interval 1.23–2.40) in patients without primary ventricular fibrillation (p=0.001).

Conclusions:

Growth differentiation factor-15 is a robust independent predictor of 30-day mortality in ST-segment elevation myocardial infarction patients with primary ventricular fibrillation.

Process Simulation-Based Design, Mold Construction and Mechanical Performance Evaluation of an Insert-Injection Molded Thermoplastic Polyurethane Part

This paper presents a case study of simulation-based design and experimental validation of the insert-injection molding process of a complex polyurethane part. The part under consideration is a dowel holder which is a machine element used in the concrete railway sleepers production. A simulation study was carried out to define the relevant mold design options and optimal molding parameters as well as to evaluate their influence on the part's quality indexes. Simulation was performed using the software Moldex3D. The mold was constructed according to the optimization analysis and a batch of pieces was manufactured under the optimized conditions. A mechanical testing experiment – representing the actual service loading conditions – was designed and performed to validate the mold and process designs and the part performance. Simulation and statistical analysis results allowed determining those conditions that lead to a better assembly between the part and the metallic insert and to its structural integrity. The mechanical performance evaluation demonstrated that the part meets all its functional and structural requirements, validating simulation predictions.

P1729Cardiogenic shock in ST elevation myocardial infarction: prevalence, management and acute phase and one-year mortality over the last three decades

Background

Cardiogenic shock (CS) is an ominous complication of ST elevation myocardial infarction (STEMI). However, the widespread use of reperfusion therapies and invasive management could have reduced the prevalence of CS and improved the prognosis of these patients in the last decades.

Purpose

The aim is to analyze the changes over last three decades in the prevalence, management and acute phase prognosis and 1-year mortality of STEMI patients complicated with CS.

Method

Between February 1989 and December 2017, 7,589 STEMI patients were consecutively admitted in the Coronary Care Unit of a University Hospital and were included in a prospective registry. Depending on the year of admission, patients were classified in five groups: 1989–1994: n=1,337, period 1; 1995–1999: n=960, period 2; 2000–2004: n=1,059, period 3; 2005–2009: n=1,535, period 4 and 2010–2015: n=2,698, period 5). We analyze the trend in prevalence of CS, management and 28-day and 1-year mortality over these five periods.

Results

The global prevalence of CS was 6.1% (466 patients), mean age was 67.7 (SD 11.7) years and 68.7% were men. Prevalence of CS in STEMI decreased from period 1 to 5 (7.3%, 6.4%, 5.5%, 5.8%, 6.0%, p<0.001), although it has been reduced more in women (10.1% in period 1 vs 8.3%, period 5, p<0.001) than in men (6.5% vs 5.4%, period 1 vs 5, respectively (p<0.001). Reperfusion therapy increased from 25.8% in period 1 (all with thrombolysis) vs 83.8% in period 5 (all with primary angioplasty). Intra-aortic balloon contrapulsation was only available from period 3 to 5, and it's used were firstly increased (20.7%, 36% and 37.9%, respectively, p<0.001). Ventricular assistance device (Impella CP) it was only available in 2017 and it was implanted in 10.5% of CS due to STEMI. Although 28-day case fatality is very high (60.7%, 283 patients), it has been reduced from period 1 to 5 (69.6%, 77.3%, 64.7%, 55.9% and 57.8%, respectively, p=0.012). This reduction in 28-day case fatality was higher in women (75.5% in period 1 vs 58.6% in period 5, p=0.12) than in men (66.8% vs 57.3, period 1–5, p=0.019). One-year mortality has been reduced between periods 1–5 (73.7% vs 61.8%, p=0.012). After multivariate adjustment, both 28-day (HR 0.63, 95% CI: 0.45–0.89, p=0.008) and 1-year mortality (HR 0.64, 95% CI: 0.45–0.90, p=0.010) have declined in the last period.

Kaplan-Meier curves, 1-year mortality

Conclusions

Cardiogenic shock development in STEMI patients has been reduced from 7.3% to 6.1% in the last three decades. The whole improvement in management of these patients achieves a 37% of reduction in 28-day case fatality and 1-year all-cause mortality. Despite this improvement, acute phase (28-day) case fatality of STEMI complicated with CS remains over 57% in the primary angioplasty era.

P865Mechanical Complications in ST elevation myocardial infarction: Trends in prevalence, acute phase prognosis and one-year mortality after the onset of reperfusion network

Background

The development of mechanical complications (MC) following an ST elevation myocardial infarction (STEMI) is associated with a high acute phase and long-term mortality. However, the widespread use of reperfusion therapies with primary angioplasty (pPCI) and surgical management could have reduced the prevalence of MC and improved the prognosis of these patients in the last years.

Purpose

The aim is to analyze the changes in the prevalence, management and acute phase prognosis and 1-year mortality of STEMI patients complicated with MC between two periods, before and after the onset of pPCI reperfusion network.

Method

We included all STEMI patients in a single centre prospective registry. Between 1990 and 2000, 2,251 STEMI patients were consecutively admitted in the Coronary Care Unit of a University Hospital (pre-pPCI period). In 2007, pPCI reperfusion program was onset in our centre. Between 2007 and 2017, 3,783 consecutive STEMI patients were included in the registry (post-pCI period). We analyze the prevalence of MC, management (reperfusion therapies, surgery ...) and 28-day and 1-year mortality among these two periods.

Results

A total of 6,034 STEMI patients were included in the registry (men 78.8%, mean age 61.7 years, SD 12.8). Patients admitted in the post-PCI period were older (62.4 vs 60.4 years, p<0.001) and have more prevalence of hypertension and dyslipidemia. Reperfusion therapy increased in post-pPCI period (89.1% vs 49.7%, p<0.001), due to widespread use of pPCI. A total of 105 patients (1.7%) develop any mechanical complication: 35 with ventricular septal rupture (VSR), 22 with papillary muscle rupture (PMR) and 48 patients with free wall rupture (FWR). Prevalence of MC has not been change between both periods. VSR occurred in 0.6% pre-PCI and 0.6% post-pPCI, p=0.98; PMR 0.3% vs 0.4% post-PCI, p=0.33; and FWR 1% vs 0.7% post-PCI, p=0.22). Overall 28-day STEMI mortality has been reduced in post-pPCI period (5.9% vs 10.1%, p<0.001 in acute phase). This 28-day mortality remains very high and without significant changes when MC appears: VSR: post-pPCI 77.3% vs 58.0%, p=0.25; PMR: 25.0% post-PCI vs 58.3%, p=0.69; and FWR: 66.4% post-PCI vs 73.7%, p=0.84). One-year mortality has not been changed between both periods and stays in a very high ratio (65.7% for VRS, 45.4% for PMR and 66.7% for FWR).

Conclusions

Although reperfusion therapy greatly increased with the onset of a pPCI reperfusion network, prevalence of MC has not been change over three decades in our series. Acute phase (28-day) and one-year mortality remains very high and without significant reduction in post-pPCI period.

Combined isolation of CD34+ progenitor cells and reduction of B cells from peripheral blood by use of immunomagnetic methods

BACKGROUND

Malignant cells may contribute to relapse after autologous hematopoietic cell transplantation The effectiveness of a double immunomagnetic purging strategy combining CD34-positive with B-negative cell selection to purge peripheral blood progenitor cells (PBPCs) from patients with chronic lymphoproliferative disorders has been analyzed.

STUDY DESIGN AND METHODS

Twenty-two CD34+ cell selections from patients with follicular lymphoma (n = 14), chronic lymphocytic leukemia (n = 6), mantle cell lymphoma (n = 1), and splenic marginal zone lymphoma (n = 1) were performed by use of a magnetic cell selector followed by a negative cell selection step with anti-CD19 monoclonal antibody bound to immunomagnetic beads.

RESULTS

The PBPC components contained median CD34+ cells of 1.24 percent (range, 0.38-3.92%) and CD19+ cells of 1.83 percent (range, 0.06-69.7%). After positive selection (n = 22), 49 percent (range, 16-72%) of CD34+ cells were recovered with a purity of 93 percent (range, 24-99%). The double-positive and -negative selections (n = 20) yielded 57.5 percent of CD34+ cells (range, 33.4-79.4%) with a purity of 95 percent (range, 63-99%). Logarithms of B-cell reduction in the CD34+-cell-enriched B-cell-depleted component had a median value of 3.63 (range, 2.74-4.84 log) and CD19+ and CD5+ cells for chronic lymphocytic leukemia patients with more than 4.56 log (>3.6-5.6 log). Of 13 PBPC components that had a tumor-specific clonal signal, 10 became PCR negative after the double-selection procedure.

CONCLUSION

Combined positive and negative magnetic cell selection achieves a high grade of tumor cell reduction with up to 77 percent of the grafts being negative for tumor-specific clonal signal by PCR analysis. This technique preserves an adequate recovery of progenitor cells able to engraft.

Closure of the fenestration in the extracardiac Fontan with the Amplatzer duct occluder device

We report the successful use of the Amplatzer duct occluder for the delayed closure of the fenestration in three patients who underwent an extracardiac modified Fontan procedure. At the moment of closure, the patients were 5.5, 2.7, and 3 years old (29 months, 3 months, and 14 months after the Fontan procedure, respectively). Immediate full occlusion was achieved in all cases. In addition, arterial saturation increased significantly (> 5%) with no hemodynamic deterioration. There were no complications during or after the procedure, and the patients were discharged in good conditions the day after and with uneventful follow-up. In conclusion, the Amplatzer duct is safe and effective for the closure of the fenestration in the extracardiac Fontan. Cathet Cardiovasc Intervent 2001;54:88-92.

Low-dose subcutaneous interleukin-2 in patients with minimal residual lymphoid neoplasm disease

Interleukin-2 (IL-2) is a cytokine that became available for clinical use with the development of recombinant DNA technology. Patients with resistant or relapsed lymphoid neoplasm have been treated with high-dose IL-2 with some responses. The aim of the present study is to determine whether there may be a biological justification for the use of low dose subcutaneous (s.c.) IL-2 as maintenance therapy in patients with lymphoid neoplasm in complete remission with high risk of relapse. We treated 15 patients with sc IL-2, 4.5 Million International Units (MIU) daily, 5 days per week for 12 consecutive weeks, in the outpatient clinic. This therapy was well tolerated and could be administered in an outpatient regimen. It increased the eosinophil count (p = 0.009), but the number of granulocytes, monocytes, T-lymphocytes and B-lymphocytes did not change. The number of natural killer (NK) cells increased from 11% to 35% of all lymphocytes during IL-2 therapy (p = 0.0006). Effector lymphokine-activated killer activity (eLAK) also increased from 6x10(-3) Lytic Units (LU)/ml to 80x10(-3) LU/ml (p = 0.02). All these changes reached a "plateau" after the 4th week of therapy. The increase in the number of NK cells correlated strongly with the increase in eLAK activity (r = 0.96, p<0.0001). Disease-free survival was determined in 14 patients who completed the treatment and compared with historical controls. Patients treated with IL-2 had the same relapse risk (median time to relapse 11.1 months, 95% confidence interval 5.5-16.6) as did controls (median time to relapse 9.7 months, 95% confidence interval 1-27.7) (p = 0.9). Low dose s.c. IL-2 stimulated NK proliferation, which generated cytotoxic activity in vivo in patients with lymphoid neoplasms. However, these patients did not have a lower risk of disease relapse compared to historical controls.

IL-6 and IL-8 levels in plasma during hematopoietic progenitor transplantation

BACKGROUND AND OBJECTIVE

The relationship between cytokine concentrations and transplant-related complications has been studied in bone marrow transplant patients. The changes in TNF-alpha, IL-1 and IL-6 concentrations after transplantation are well documented in the literature but this is not the case for IL-8. The purpose of the present study was to investigate prospectively the plasma concentration of these cytokines and their relationship to transplant-related complications.

DESIGN AND METHODS

Pro-inflammatory cytokine (TNF-alpha, IL-1, IL-6 and IL-8) levels in plasma were determined in a group of 53 patients undergoing hematopoietic progenitor transplantation. Plasma samples were collected weekly from day -7 to day +35 and stored at -70 degrees C until assayed by ELISA. The major transplant-related toxicities registered were: veno-occlusive disease (VOD), acute graft-versus-host disease (GVHD), infectious episodes, renal failure and mucositis.

RESULTS

In spite of the great variability of plasma cytokine profiles between the different patients, we came to various conclusions. Patients' TNF-alpha and IL-1 concentrations correlated well over time. IL-6 and IL-8 profiles were similar and correlated well with febrile episodes. In some cases, an increase in IL-6 preceded hematologic recovery. In our study, increased levels of TNF-alpha, IL-6 and especially IL-8 correlated with hepatic or renal dysfunction as evaluated by increased bilirubin and creatinine in plasma, while pulmonary complications correlated only with increased IL-6 levels. Allogeneic transplant patients had a tendency to have higher TNF-alpha concentrations than autologous transplant patients, probably because an allogeneic transplant is associated with more transplant-related toxicity. Basal disease usually had no effect on cytokine profiles.

INTERPRETATION AND CONCLUSIONS

IL-6 and IL-8 were the only cytokines studied whose increase correlated with febrile episodes. High IL-8 values may be a useful predictor of renal dysfunction and pulmonary disease and seems to trigger off high IL-6 levels. Plasma TNF-alpha and IL-1 concentrations during the posttransplant period have not been shown to be predictive of the development of transplant-related complications, and none of the profiles was recognized to be specific for a particular complication in this study.

High-titer retroviral vectors containing the enhanced green fluorescent protein gene for efficient expression in hematopoietic cells

Retroviral vectors constitute the most efficient system to deliver and integrate foreign genes into mammalian cells. We have developed a producer cell line that yields high titers of amphotropic retroviral vectors carrying the enhanced green fluorescent protein (EGFP) gene, a codon humanized, red-shifted variant of the green fluorescent protein (GFP) gene, which can be used as a selectable marker. We have used a hybrid vector that has been shown to efficiently drive gene expression in hematopoietic cells. Virtually all murine and human cell lines and primary human hematopoietic cells tested were transduced with varying efficiency after incubation with vector-containing supernatants. Human CD34(+) cells obtained from cord blood or aphereses products were transduced using a protocol that involves daily addition of vector-containing supernatants for 6 consecutive days. At day 6, up to 16% of the cells expressed EGFP, as assessed by flow cytometry. Sorted EGFP-expressing cells were able to produce fluorescent hematopoietic colonies. EGFP's main advantages are its fast flow cytometry determination and the possibility of cell sorting and simultaneous evaluation of the transduction efficiency along with other phenotypic markers.

High-dose systemic interleukin-2 therapy in stage IV neuroblastoma for one year after autologous bone marrow transplantation: pilot study

Despite intensified chemotherapy protocols, including autologous bone marrow transplantation (ABMT), stage IV neuroblastoma has a poor prognosis, and modern therapeutic trends are aimed at the eradication of minimal residual disease, which is though to be the main factor leading to relapse. In this pilot study, we report the systemic administration of high doses of interleukin-2 after ABMT in four patients. Five day cycles of IL-2 at a dose of 18 x 10(6) IU/m2/day were administered at variable time intervals as frequent as it was necessary to maintain the levels of natural killer (NK) cytotoxic activity higher than the median control value (40 LU/ml blood) throughout 1 year from the start of first IL-2 treatment. After IL-2 infusion, NK and LAK activities increased significantly (median 742 x 10(-3) LU/ml blood and 186.8 x 10(-3) LU/ml blood, respectively). Toxicities were transient and no life-threatening complications were observed. Fever, anorexia, skin rash and enlarged liver were always present. Anaemia, thrombocytopenia, leukocytosis, lymphocytosis and and eosinophilia occurred following most of the IL-2 courses. Although the small number of patients does not allow an estimation of the immunomodulatory-antineoplasic effects of IL-2, the results seem promising for the management of neuroblastoma patients.

Interleukin-2 in neuroblastoma: clinical perspectives based on biological studies

Stage IV neuroblastoma (NB) is a disease with a poor prognosis. Chemotherapeutical intensification and hematological rescue with autologous bone marrow transplantation (ABMT) achieve some complete remissions (CR), but most patients relapse during the first year. Immunotherapy could be an alternative in this situation of high risk of relapse due to residual disease and ABMT-related immunodepression. Ten stage IV NB patients in CR or very good partial remission have been treated with recurrent 5-day cycles of high doses of Interleukin-2 (IL2) after ABMT throughout one year (usually 5-6 cycles). Natural killer (NK) and lymphokine-activated killer (LAK) cytotoxic activities, as well as phenotype and number of circulating NK cells were determined, before and after each course of IL2 treatment. The effects promoted by IL2 varied during treatment: early cycles of IL2 induced a great extent of cell expansion, mainly on CD3-/CD16-/CD56+bright and CD8+dim cell phenotypes; conversely, late courses of IL2 promoted higher NK cytotoxic activity but a lesser increase on circulating NK cells. The induction of LAK activity did not significantly differ from early and late IL2 treatments. Clinical results are still inconclusive due to the small number of patients. The median follow-up of patients treated with IL2 is 24 months and the disease free survival (DFS) probability is 0.80 +/- 0.12 vs 0.16 +/- 0.15 from a historical control with identical treatment, but in the absence of IL2 treatment (p < 0.005). IL2 treatment-related toxicity was mild and no interruption of the treatment was required. Extremely accurate hydric control was carried out to avoid, as much as possible, the consequences of vascular leak syndrome, one of the most important toxic effects of IL2 treatment. The results presented here suggest an evolution of NK activity during IL2 treatment after ABMT, which should be taken into account for the designing of new immunotherapeutical protocols and opens a promising perspective in treatment of stage IV neuroblastoma.

Recombinant adeno-associated virus-mediated high-efficiency, transient expression of the murine cationic amino acid transporter (ecotropic retroviral receptor) permits stable transduction of human HeLa cells by ecotropic retroviral vectors

Adeno-associated virus has a broad host range, is nonpathogenic, and integrates into a preferred location on chromosome 19, features that have fostered development of recombinant adeno-associated viruses (rAAV) as gene transfer vectors for therapeutic applications. We have used an rAAV to transfer and express the murine cationic amino acid transporter which functions as the ecotropic retroviral receptor, thereby rendering human cells conditionally susceptible to infection by an ecotropic retroviral vector. The proportion of human HeLa cells expressing the receptor at 60 h varied as a function of the multiplicity of infection (MOI) with the rAAV. Cells expressing the ecotropic receptor were efficiently transduced with an ecotropic retroviral vector encoding a nucleus-localized form of beta-galactosidase. Cells coexpressing the ecotropic receptor and nucleus-localized beta-galactosidase were isolated by fluorescence-activated cell sorting, and cell lines were recovered by cloning at limiting dilution. After growth in culture, all clones contained the retroviral vector genome, but fewer than 10% (3 of 47) contained the rAAV genome and continued to express the ecotropic receptor. The ecotropic receptor coding sequences in the rAAV genome were under the control of a tetracycline-modulated promoter. In the presence of tetracycline, receptor expression was low and the proportion of cells transduced by the ecotropic retroviral vector was decreased. Modulation of receptor expression was achieved with both an episomal and an integrated form of the rAAV genome. These data establish that functional gene expression from an rAAV genome can occur transiently without genome integration.

Progression of natural immunity during one-year treatment of residual disease in neuroblastoma patients with high doses of interleukin-2 after autologous bone marrow transplantation

The aim of this work was to monitor the functional and phenotypic variations of natural killer (NK) cells in seven children with stage IV neuroblastoma (NB) treated with recurrent 5-day cycles of interleukin-2 (IL-2) at a dose of 18 x 10(6) IU/m2/d by continuous intravenous infusion. All patients who entered the study had no detectable disease after hematologic recovery from intensive chemotherapy and autologous bone marrow transplantation (ABMT). To evaluate the effect of this treatment on tumor relapse, IL-2 immunotherapy was adjusted to maintain levels of NK activity above those of age-matched controls (threshold of 40 lytic units [LU]/10(9) mononuclear cells) during a 1-year period since hematologic recovery of ABMT. The levels of NK and endogenous lymphokine-activated killer (eLAK) cell cytotoxic activities, as well as phenotype-differentiated lymphocyte counts, were determined from patients' freshly isolated peripheral blood mononuclear cells (MNC). Data were analyzed at different points between each cycle of IL-2, and before and 36 hours after each infusion. NK and eLAK activities significantly increased in response to IL-2. Both cytotoxic parameters correlated with the serum levels of the soluble IL-2 receptor (sIL-2R). IL-2 increased the amounts of NK and T cell subsets but not of B cells. The effects of IL-2 were time-dependent. Early cycles of IL-2 preferentially increased cell numbers, especially of cells bearing a CD3-/CD16-/CD56+bright and CD8+dim phenotype. Conversely, late courses promoted higher cytotoxic effects but with a smaller increase in NK and T cell counts; the main NK subset became CD16+, and CD8+dim cells remained a minor subset. It is worthy to note that the patient who relapsed after completing immunotherapy showed only a slight increase of the NK subset in response to IL-2. These results show the feasibility of sustaining an increased NK activity during 1 year after ABMT in children with advanced neuroblastoma and suggest the occurrence of changes in the functional and phenotypic characteristics of the NK cells generated throughout the 1-year treatment.

Higher cytotoxic activity and increased levels of IL-1 beta, IL-6, and TNF-alpha in patients undergoing cardiopulmonary bypass

Extracorporeal circulation (EC) by surgical bypass is often associated with a systemic inflammatory response. The purpose of this study was to assess the effect of EC on the serum levels of pro-inflammatory mediators Interleukin (IL)-1 beta, IL-6, tumor necrosis factor (TNF)-alpha, and soluble CD-23. Peripheral blood lymphocyte subsets and natural killer cell (NK) cytotoxic activity were also analyzed before and after the bypass process. The results from eight patients who underwent cardiac surgery showed a significant increase in the levels of IL-1 beta, IL-6, and TNF-alpha, a decrease in CD4+/CD8+ lymphocyte ratio, and an overstimulated NK cytotoxic activity. These changes on serum cytokine levels and cellular immunology parameters could play an important role in the development of adverse effects associated with EC.

Presentation of a PCR-nuclease protection strategy for minimal residual disease monitoring in B-ALL

Methods for detecting residual malignant cells in patients suffering from lymphoid malignancies have neither been sufficiently sensitive nor easy to routinize, hampering a potential prediction of disease outcome. Taking advantage of clone-specific DNA sequences, generated during lymphocyte differentiation and the polymerase chain reaction, some strategies have been developed for several groups. Up to now the most specific and sensitive methodology, which consists of designing leukemia-specific oligonucleotides, requires sequencing of the complementary determining region III-DNA for each particular patient and is too laborious to be applied to each case for routine monitoring in most hospital laboratories. In an attempt to achieve an easy way to detect residual malignant cells in B lymphoproliferative diseases, we have used a new PCR-based approach, named here as PCR-nuclease protection assay, consisting of: (i) amplification of DNA segments corresponding to the complementarity determining region III of the immunoglobulin heavy chain genes from samples at disease diagnosis; (ii) isolation of the disease-specific single-stranded DNA; (iii) labeling of the single-stranded DNA to generate specific probes; (iv) hybridization to amplified DNA from samples corresponding to different disease phases; and (v) digestion with S1-nuclease. Using this approach, we could detect one malignant cell in a background of 10(5) healthy cells. The sensitivity and specificity of this approach compares with those of the above mentioned specific oligonucleotide strategy in detecting residual malignant B cells. Moreover, this strategy is much less tedious and could be used by most hospital laboratories.

Differential effect of cryopreservation on natural killer cell and lymphokine-activated killer cell activities

The use of lymphokine-activated killer (LAK) cell therapy in delayed treatment requires the use of cryopreserved effector cells. The purpose of this study was to determine the optimal cryopreservation protocol for the maintenance of cytotoxic activity in mononuclear cells (MNCs). MNCs were cryopreserved with dimethyl sulfoxide or 1,2-propanediol before and after 3 days of culture with recombinant interleukin 2. The effects of cryopreservation on cell recovery, LAK cell and natural killer (NK) cell cytotoxic activities, and surface antigen markers were studied. Recovery of nonactivated MNCs was higher with 1,2-propanediol than with dimethyl sulfoxide (p < 0.05). Cytotoxic activities, measured with a 51Cr release assay, significantly decreased after thawing, on both activated cells (76.3%; range, 35.8-92.2%) and fresh cells (54.6%; range, 17.5-75.4%). A 6-day kinetic test was used to compare the cytotoxic activity of cryopreserved and fresh cells. The results showed different patterns for NK cells (cryopreserved cells had lower levels of activity than fresh cells) and LAK cells (cryopreserved cells had higher levels of activity than fresh cells). Phenotype changes of effector cells in culture, with and without cryopreservation, were monitored by flow cytometry using monoclonal antibodies. These results were compared with changes in the cytotoxicity of cells with and without cryopreservation. After thawing, there was a decrease in MNCs expressing CD14 and CD56. Recovery of the CD56 marker correlates with increased cytotoxic activity. Despite some loss of NK cell activity, it is concluded that MNCs may be successfully cryopreserved before their use in immunotherapeutic treatment.

Abnormal levels of platelet-specific proteins and mitogenic activity in myeloproliferative disease

It has been postulated that platelet-derived growth factor and platelet factor 4 (PF4) are involved in the imbalance of the mechanism of medullar stroma maintenance which triggers off the bone marrow myelofibrotic process. In this work we compare the PF4 and the beta-thromboglobulin (beta-TG) and mitogenic activity in platelet-poor plasma (PPP) and platelet extracts (PE) from patients with myeloproliferative disorders (MPD) with those of secondary thrombocytosis (ST) and normal volunteers. Statistically significant differences were found between MPD and ST patients or controls, but none between ST and controls in all the parameters studied. Maximal differences in platelet-derived factors (PDFs) between MPD and control groups were found in polycythemia vera patients. However, the relationship between the presence of myelofibrosis and abnormal levels of beta-TG, PF4 and mitogenic activity in PPP and PE was only observed in patients with agnogenic myeloid metaplasia (AMM). These results show that PDFs are specifically decreased in MPD platelets. Furthermore, no statistical correlation was found between PDFs and the number of platelets. However, other unknown factors or conditions would be necessary to develop myelofibrosis in MPD, which is present in AMM.

Different lymphocyte activity in patients with polycythaemia vera versus secondary polycythaemia and healthy blood donors

On comparing lymphocyte patterns in patients with polycythaemia vera (PV) versus healthy blood donors (NC) and patients with secondary polycythaemia (SP), we observed an altered CD4/CD8 ratio (p less than 0.01) mainly due to the decreased CD8 subpopulation in PV. We found an increased lymphocyte activity in PV patients when compared with both SP and NC: the interleukin 2 (IL-2) production was significantly higher (p less than 0.001) as was the lymphoproliferative response both to phytohaemagglutinin (p less than 0.001) and IL-2 (p less than 0.005). No significant differences were found between NC and SP. None of the PHA-stimulated PBMC samples from PV, SP or NC produced erythropoietin (EPO)-like or EPO-inhibitory activity. Our findings suggest an altered lymphoid lineage in PV patients.

Transforming growth factor release by human tumor cell lines and their interactions with other growth factors

We have studied the production of transforming growth factor (TGF) by several human tumor cell lines and their interactions with exogenously added epidermal growth factor (EGF) and insulin. TGF-like activities were present in all the conditioned media tested. The clonogenic capacity of the tumor cell lines had no correlation with the TGF-like activity production. EGF and insulin had a promoting colony-forming activity on tumor cells but this effect was not additive. Moreover, an inverse statistically significant correlation (-0.817, p less than 0.05) was found between the response to exogenous EGF and the EGF or TGF-alpha production by tumor cell lines. The EGF receptor (EGF-R) was not detected in any of the melanomas studied, nor in breast adenocarcinoma cell lines which were producers of EGF or TGF-alpha.

Artefactual low lymphocyte activity caused by platelet contamination in the mononuclear cell preparations

Platelet (PLT) contamination in preparations of mononuclear cells (MNC) produces a significant decrease (P less than 0.02) in lymphoproliferative activity and interleukin 2 (IL2) production. This effect was observed in MNC preparations from either healthy blood donors or polyglobulic patients. In a dose-response curve carried out with increasing PLT number per MNC, progressive inhibition was found, reaching to 62.6% and 49.5%, respectively, to phytohemagglutinin and IL2 lymphoproliferative response and 87.8% in IL2 production, at 80 PLTs/MNC.