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Biomedical subjects

L Bossaert

Publications and source records attributed to L Bossaert.

At least 55 records · Page 3Linked to original sources
PubMed1996

Acute poisoning with amphetamines (MDEA) and heroin: antagonistic effects between the two drugs.

A case of oral ingestion of large doses of both the amphetamine-derivative 3,4-methylene dioxyethamphetamine (MDEA) and heroin is reported. Despite high serum levels of both drugs, the patient did not present with the classic signs and symptoms normally seen during intoxication with these drugs. The patient recovered after symptomatic treatment. The possibility that opposite pharmacological properties of the two drugs prevented the patients death is discussed.

3,4-Methylenedioxyamphetamine↗
PubMed1996

N-acetylcysteine pretreatment of cardiac surgery patients influences plasma neutrophil elastase and neutrophil influx in bronchoalveolar lavage fluid.

OBJECTIVE: Study of leukocyte activation and release of toxic mediators during extracorporeal circulation (ECC). ECC can be used to study the potential protective effect of a pharmacon against neutrophil-mediated lung injury. Clinical studies have indicated that N-acetylcysteine (NAC) may improve systemic oxygenation and reduce the need for ventilatory support when given to patients with acute lung injury. DESIGN: Cardiac surgery patients were pretreated with high-dose NAC in order to assess the potential role of NAC to interfere with neutrophil-mediated inflammation and lung injury. PATIENTS: 18 patients who underwent ECC: group 1 (n = 8) no premedication (only placebo); group 2 (n = 10) NAC (72 mg/kg i.v. as a bolus, later 72 mg/kg over 12 h). MEASUREMENTS AND RESULTS: In group 2, the partial pressure of oxygen in arterial blood/fractional inspired oxygen 4 h after surgery was significantly higher than in group 1 (213 +/- 31 vs 123 +/- 22; p = 0.044). NAC pretreatment prevented an increase in plasma neutrophil elastase activity (18.9 +/- 6.9 vs 49.9 +/- 5.6 ng/ml in group 1 at the end of ECC; p = 0.027). Release of myeloperoxidase (MPO) was not affected (group 1:1105 +/- 225 ng/ml vs group 2:1127 +/- 81 at the end of ECC; p = 0.63). At the end of ECC, total antigenic human neutrophil elastase (group 1:671 +/- 72 ng/ml vs group 2:579 +/- 134; p = 0.37) and complex formation between elastase and alpha 1-proteinase inhibitor were no different in the two groups. There were no significant difference in cellular composition and mediators in the lavage fluid, although values for total number of neutrophils, elastase, MPO and interleukin-8 were lower in group 2. CONCLUSION: Pretreatment with NAC may prevent lung injury by diminishing elastase activity. Since the release of mediators, especially MPO, is not affected, this diminished activity of elastase may be achieved by enhanced inactivation by antiproteases after initial treatment.

Acetylcysteine↗
PubMed1995

A 2,4-dichlorophenoxyacetic acid induced fatality.

This paper reports on a fatal intoxication by oral ingestion of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). At admission, the victim was unconscious. His condition deteroriated rapidly with blood loss from his mouth and nose. Since the cause of this condition was not known, gastroscopy was performed and haemorrhagic mucosa was observed in the mouth, oesophagus and stomach. Gastric contents (removed by lavage), urine and blood were submitted for toxicological analysis. Unfortunately, within 3 h of admission (about 5 h following ingestion of the toxin) profound cardiogenic shock developed and the patient died. The identity of the toxic xenobiotic was revealed by gas chromatography-mass spectrometry. Analytical quantification of the herbicide was performed by acid extraction prior to gas chromatographic examination using electron capture detection. His blood level of 2,4-D was 192 mg l-1.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1995

Potential role of Clara cell protein, an endogenous phospholipase A2 inhibitor, in acute lung injury.

It is now recognized that epithelial cells lining airways and alveoli are capable of releasing various mediators, which have the potential to modulate local inflammatory reactions. The amount of the 16 kDa Clara cell protein (CC16), an inhibitor of phospholipase A2 activity produced by pulmonary epithelial cells, was measured by means of a sensitive immunoassay in the unconcentrated bronchoalveolar lavage fluid (BALF) of 13 control subjects, and in patients with acute lung injury (14 with the full-blown adult respiratory distress syndrome (ARDS); 21 after standard cardiopulmonary bypass surgery, a known risk factor for ARDS). The level of CC16 was compared with other markers of inflammation with a wide range of molecular weights: albumin (nephelometry); total protein (spectrophotometry); beta 2-microglobulin (latex immunoassay); cystatin C (latex immunoassay); alpha 1-antitrypsin (immunoradiometry), and lipocortin-1 (enzyme-linked immunosorbent assay (ELISA)). The Clara cell protein (CC16) was detectable in all BALF, and significantly higher levels of this protein were observed in BALF from patients with acute lung injury. Changes in BALF Clara cell protein levels differed from those of alpha 2-macroglobulin and the natural phospholipase inhibitor lipocortin-1. Alpha 2-macroglobulin levels were not significantly enhanced in patients at risk for ARDS, but were increased in patients with ARDS; whereas, lipocortin 1 levels were not elevated in either group. Pretreatment of patients at risk for ARDS with high dose methylprednisolone did not alter the amount of Clara cell protein recovered in BALF. The mean CC16 level in BALF from patients with ARDS who died was significantly lower than from those who survived. The data presented in this study suggest that pulmonary epithelial cells secrete a natural anti-inflammatory protein during acute lung injury, which might have a protective and immunosuppressive role.

Adult↗
PubMed1994

Pretreatment with methylprednisolone in coronary artery bypass grafting influences the levels of histamine and tryptase in serum but not in bronchoalveolar lavage fluid.

1. The presence of histamine and tryptase in serum during and after coronary artery bypass grafting may be an indication of the induction of inflammation. 2. One group of patients received no glucocorticoids and a second group received methylprednisolone before extracorporeal circulation. In the steroid group no effects were seen on the basal levels of histamine (2.84 +/- 0.12 ng/ml) and tryptase (0.50 +/- 0.05 ng/ml) during and after surgery. In the other group two peak levels of histamine were observed: one at 10 min after starting extracorporeal circulation (4.19 +/- 1.79 ng/ml) and another at 4 h after surgery (8.26 +/- 4.85 ng/ml). In this group tryptase was only elevated during the period of extracorporeal circulation (1.54 +/- 0.16 ng/ml). 3. There were no differences between the two groups in complement activation. C3a levels rose to 170 +/- 8% and 180 +/- 10% of the initial value in the steroid and non-steroid group, respectively. 4. It was concluded that during surgery mast cells were activated, but since tryptase levels decreased in the post-operative period, the second increase in the histamine level can be explained by activation of basophils or by an unknown mechanism for the release of histamine but not tryptase by mast cells. 5. In the bronchoalveolar lavage fluid the levels of histamine and tryptase showed no differences between the two groups of patients, but histamine was enhanced compared with normal levels.

Bronchoalveolar Lavage Fluid↗
PubMed1993

Thrombolytic therapy.

All patients with symptoms and ECG findings suggestive of acute myocardial infarction (AMI) should be considered for treatment with thrombolytic agents. The decision to use thrombolytic therapy is a clinical judgment based upon a weighing of the potential benefits versus the possible risks. The physician must take into account relative contraindications, age of the patient, area of jeopardized myocardium, and duration of symptoms. Health professionals involved in the care of AMI patients should develop written plans and protocols addressing the following matters: identification of patients with chest pain in the prehospital setting (this applies to hospitals that receive patients from emergency medical services systems), triage of patients in the emergency department, obtaining the 12-lead electrocardiogram, determination of contraindications, authority for ordering thrombolytic therapy, and consultation for atypical cases. There also should be agreed standards for the time interval from arrival in the ED to administration of the thrombolytic agent, as well as a commitment to the prospective monitoring of procedures and times to assure continuous improvement. A time interval for treatment (arrival in ED to administration of drug) of 30 to 60 minutes should be achievable for patients who present with typical symptoms and ECG findings.

Acute Disease↗
PubMed1993

Interleukin-8 production in patients undergoing cardiopulmonary bypass. The influence of pretreatment with methylprednisolone.

Pulmonary dysfunction caused by pulmonary neutrophil sequestration is a frequent postoperative complication in patients undergoing cardiopulmonary bypass (CPB) surgery. It is yet unclear whether treatment with corticosteroids in vivo in these patients can prevent complement-mediated neutrophil activation and sequestration in the lungs. Therefore, we conducted a prospective study in order to investigate whether methylprednisolone (MP) pretreatment (30 mg/kg) could influence the appearance of IL-8 (a recently discovered cytokine with potent neutrophil-chemotactic activity) in the peripheral circulation. We also studied the effects of MP pretreatment on the inflammatory parameters in the bronchoalveolar lavage (BAL) fluid 4 h postoperatively. Although peripheral neutropenia and the rise in IL-8 serum levels was less pronounced in MP-treated than in non-steroid-treated patients, there was no significant difference in albumin, total protein, concentrations of IL-8 and C3a, and the number of neutrophils in the BAL fluid between the two groups. However, when cultured in vitro, alveolar macrophages from patients treated with MP released significantly lower IL-8, both in basal conditions and after stimulation with lipopolysaccharide. Our results show that MP does not prevent (IL-8-mediated) pulmonary neutrophil infiltration after CPB, although it might affect certain aspects of the microvascular lung injury.

Aged↗
PubMed1992

Release of arachidonic acid metabolites from isolated human alveolar type II cells.

Human alveolar type II cells are thought to play a role in the pathogenesis of lung injury. Patterns of mediator release of arachidonic acid metabolism by type II cells were therefore studied after challenge with calcium ionophore A23187, opsonized zymosan and hydrogen peroxide. A time- and concentration dependent release of cyclooxygenase products was observed, with release of PGE2 greater than 6-keto-PGF1 alpha greater than TxB2. Addition of glutathione or bicarbonate further increased the production of PGE2. N-ethylmaleimide, a sulfhydryl (SH) reactant, induced a dose-dependent increase in the release of TxB2 and 6-keto-PGF1 alpha, but not of PGE2. This relates most likely to the SH-dependency and glutathione requirement of the PGE2 isomerase and SH-independence of thromboxane and prostacyclin isomerase.

Arachidonic Acid↗
PubMed1992

Interleukin 8 (IL-8) in the bronchoalveolar lavage fluid from patients with the adult respiratory distress syndrome (ARDS) and patients at risk for ARDS.

A sensitive and specific radioimmunoassay was used to measure interleukin 8 (IL-8) in bronchoalveolar lavage fluids from control subjects, patients with the adult respiratory distress syndrome (ARDS) and patients undergoing coronary bypass surgery, a risk factor for developing ARDS. Concentrations of IL-8, albumin, total protein and numbers of neutrophils were higher in both patient groups than in controls. Levels of IL-8 were significantly correlated with the influx of neutrophils, plasma protein extravasation and with the PaO2/FiO2 ratio. These data suggest that IL-8 may mediate the recruitment of neutrophils from the vascular compartment into the alveolar space and may therefore be an important determinant in neutrophil-mediated lung injury. Since increased levels of IL-8 were also found in BAL fluid from patients at risk in whom ARDS did not develop, other factors are likely to be involved and IL-8, as well as other markers of inflammation, are of little prognostic use.

Adult↗
PubMed1992

Should semi-automatic defibrillators be used by emergency medical technicians in Belgium? The Belgian Cerebral Resuscitation Study Group.

Early external defibrillation is the single most effective intervention in patients with out-of-hospital cardiac arrest. Literature data indicate that instructing emergency medical technicians (EMTs) to use defibrillators is beneficial, provided the local emergency medical system is well organized. We tried to estimate the potential benefit of early defibrillation in some centres in Belgium by retrospectively analyzing the data from the Belgian Cardio-Pulmonary-Cerebral Resuscitation Registry collected between 1983 and 1987 in Belgian centres with a Mobile Intensive Care Unit (MICU). The data show that 2310 out of 3371 patients (69%) were first attended by the EMTs; on subsequent arrival of the MICU-teams, 584 of these 2310 patients i.e. 17% of the whole study population, presented with ventricular fibrillation. Analysis of estimated time factors in these 2310 patients revealed that the median time interval between collapse and start of resuscitation by EMTs was 8 min; the median time interval between collapse and start of MICU-resuscitation attempts was 16 min. The duration of EMT-resuscitation before MICU-arrival was probably more than 5 min and 10 min in 58% and 23% of the cases respectively. It is concluded that EMTs can be expected to reach a substantial number of ventricular fibrillation victims within a few minutes after the collapse and many minutes before arrival of the MICU. Therefore, training of EMTs in the use of semi-automatic defibrillators seems worthwhile in MICU-served regions in Belgium.

Belgium↗
PubMed1991

ST-segment analysis: a useful marker for reperfusion after thrombolysis with APSAC? The Belgian EMS Study Group.

The European Multicentre Study (EMS) assessed coronary reperfusion, functional outcome and safety of anistreplase (anisoylated plasminogen streptokinase activator complex = APSAC) compared to a control group treated with heparin alone in patients with a clinical diagnosis of acute myocardial infarction (AMI). In the Belgian subset of data (n = 103) the reperfusion results, based on non-invasive clinical parameters, were significantly better in the APSAC group: 66% versus 18% in the heparin group (P less than 0.0001). No significant difference was found between the two treatment groups with respect to left ventricular function and adverse events. The purpose of the present study was to analyse the indicative value of ST-segment changes as a possible predictor of reperfusion in threatened myocardial tissue. Two scoring systems were used: the first was based on the combined evaluation of three clinical non-invasive parameters (course of chest pain, ECG evaluation of ST segment changes, reperfusion arrhythmias); the second was based on the changes of the sum of the ST-segment (sigma-ST) evaluations on consecutive 12-lead ECGs. There was a good correlation between the combined clinical scoring system and the residual stenosis on coronary angiography (P less than 0.05) and early CK peak (P less than 0.0001). Analysis of the ECG data revealed that a decrease of greater than or equal to 50% of the sum of ST-elevations (sigma-ST) at 2 h post-treatment in both limb and precordial leads is a fairly useful predictor of reperfusion (sensitivity = 73%, specificity = 63%, predictive value = 88%).

Adult↗