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Biomedical subjects

I Engelberts

Publications and source records attributed to I Engelberts.

11 recordsLinked to original sources

[Penetrating heart injuries in two butchers].

Two butchers, men aged 25 and 48 years, sustained a perforating heart injury when they made a vertical cut. They were rushed to hospital. The first patient was haemodynamically stable on arrival. The second had hypotension and cardiac ultrasonography revealed increased fluid in the pericardium; he was subjected to pericardiocentesis. The heart wounds in both patients were sutured via a left-sided anterolateral thoracotomy; the younger had a wound in the left ventricle, the older both a dorsal and a ventral transmural perforation of the right ventricle. Both patients could be discharged after a little over a week in good condition. Employers in abbattoirs should provide protective clothing fastening high enough to prevent heart wounds.

Abattoirs↗

High-output cardiac failure due to excessive shunting in a hemodialysis access fistula: an easily overlooked diagnosis.

A dialysis arteriovenous fistula caused life-threatening high-output cardiac failure in a 66-year-old patient. Excessive shunting through the dialysis fistula was demonstrated by invasive measurement of cardiac output, systemic arterial blood pressure, systemic vascular resistance, and oxygen consumption before and after temporary occlusion of the dialysis fistula. Noninvasive echocardiographic evaluation of the influence of fistula compression on cardiac output and noninvasive duplex measurement of the fistula flow also confirmed the diagnosis. Following surgical closure of the fistula, the patient's condition improved, and signs of congestive heart failure subsided. High-output cardiac failure is a rare complication of dialysis arteriovenous fistulas. The diagnosis may remain unrecognized for longer periods. Noninvasive methods for estimation of the hemodynamic importance of a fistula may be of help in the establishment of the proper diagnosis.

Aged↗

Effect of hemodialysis on peripheral blood monocyte tumor necrosis factor-alpha, interleukin-6, and interleukin-8 secretion in vitro.

The influence of blood-membrane interaction on human peripheral blood monocyte tumor necrosis factor-alpha (TNF), interleukin-6 (IL-6), and interleukin-8 (IL-8) secretion was measured during hemodialysis of end-stage renal disease patients by in vitro stimulation of whole blood with lipopolysaccharide. Monocyte TNF and IL-6 secretion in vitro was reduced 30 min after start of dialysis session. In contrast, cellular IL-8 secretion did not change during hemodialysis. Comparison of the results of three different membranes indicates that the bioincompatibility of the dialysis membrane was reflected in both leukocytopenia and reduction of cellular TNF secretion. During treatment of normal whole blood in an ex vivo dialysis closed-loop circuit, the ability of monocytes to release TNF, IL-6, and IL-8 in vitro remained constant. This indicates that the reduced IL-6 and TNF secretion during standard hemodialysis was not due to a direct effect of contact between dialysis membranes and monocytes, but rather was a result of redistribution within the patients' leukocyte pool.

Adult↗

The effect of replacement of dietary fat by palm oil on in vitro cytokine release.

In the present study the effect of replacement of dietary fat by palm oil in the normal Western diet on the in vitro release of the inflammatory cytokines tumour necrosis factor (TNF), interleukin (IL)-6 and IL-8 was examined. A maximal replacement of 700 g/kg dietary fat was achieved for thirty-eight male volunteers who consumed either a palm-oil diet or a control diet in a double-blind, cross-over study with 6-week experimental periods, and 3-week run-in and wash-out periods. At the end of both experimental periods, whole blood was stimulated in vitro with 0.02 (sub-optimal), or 10 ng lipopolysaccharide (LPS)/ml (maximal), whereafter TNF, IL-6, and IL-8 concentrations in the culture supernatant fraction were measured using specific enzyme-linked immunosorbent assays (ELISA). Mean cytokine production with sub-optimal, or maximal LPS stimulation of peripheral whole blood was similar for both the palm oil, and the control group. The relative TNF response, however, was reduced by replacement of dietary fat with palm oil. Separate analysis of the data from the first and second experimental periods strongly suggested that the residual effect of the palm-oil diet on the relative TNF response was longer than 9 weeks. Cytokine homeostasis determines the course of the inflammatory response and the progression of atherosclerosis. The effect of palm-oil consumption on the proneness of the peripheral blood cells to produce TNF may, therefore, alter the prevalence of these common diseases.

Adult↗

A role for ELAM-1 in the pathogenesis of MOF during septic shock.

As a model for septic shock, LPS was infused into anesthetized Cynomolgus monkeys. Hematologic and metabolic parameters proved the induced shock response. The data presented show that administration of LPS to Cynomolgus monkeys induced a generalized inflammatory status, which was characterized by systemic release of the cytokines TNF and IL-6. Further it was demonstrated, using immune-histological methods, that a generalized expression in vivo of the endothelial leukocyte adhesion molecule (ELAM)-1 was induced on endothelial cells by LPS infusion. ELAM-1 expression was most pronounced on vasculature of lung tissue and skin. As shown in serial skin biopsies, ELAM-1 expression was induced rapidly: at 2 hr after the onset of LPS infusion, reaching maximum after 4 hr. The expression of ELAM-1 is considered to be of relevance for the mechanism which underlies the stasis of PMN in the tissues during septic shock.

Animals↗

Administration of tumor necrosis factor alpha (TNF alpha) inhibitors after exposure to TNF alpha prevents development of the maximal biological effect: an argument for clinical treatment with TNF alpha inhibitors.

The cytokine tumor necrosis factor alpha (TNF alpha) is involved in the pathophysiology of a wide variety of diseases. Pretreatment with anti-TNF alpha antibodies has proven its success in animal models of disease. The question, however, whether intervention with anti-TNF alpha antibodies might be useful in the clinical situation in which TNF alpha is already produced is still unanswered. We therefore studied the relation between the duration of TNF alpha/TNF receptor interaction and the extent of the induced biological effects in two different in vitro systems: (1) the slowly induced cytotoxicity of the TNF-sensitive murine cell line L929, and (2) the rapid TNF alpha-induced expression of an adhesion molecule for the polymorphonuclear cell, ELAM-1 on human endothelial cells. The TNF alpha/TNF receptor interaction was interrupted at different times after onset of stimulation, either by washing away TNF alpha or by adding TNF alpha activity-blocking monoclonal antibody. To establish an optimal effect for both TNF alpha-induced cytotoxicity on L929 cells and TNF alpha-induced expression of ELAM-1 on human endothelial cells, the TNF receptor had to be occupied by TNF alpha for at least 30-60% of the full incubation period. This observation provides an argument that clinical intervention with TNF alpha inhibitors can be advantageous, even in a situation in which TNF alpha has already been released into the circulation.

Animals↗

Generalized inflammation during peritonitis evidenced by intracutaneous E-selectin expression.

E-selectin is a human endothelial leukocyte adhesion molecule which is expressed on endothelial cells after exposure to inflammatory mediators and which is known to be involved in the adhesion of polymorphonuclear cells to the endothelium in vitro. Data on E-selectin expression in vivo are limited. In the present report, we studied the expression of E-selectin in skin biopsies from patients with peritonitis due to a perforation of the gastrointestinal tract. Substantial E-selectin expression was observed on the vasculature of the skin from six out of eight of these severely ill patients. Skin obtained from healthy individuals stained negative, or showed a faint patchy staining in 30% of biopsies tested. These results provide evidence that E-selectin expression was induced at a distance from the primary inflammatory process on the vascular endothelium of the skin during severe peritonitis. Cutaneous E-selectin expression thus reflected on the surface of the body a state of generalized activated endothelium.

Cell Adhesion Molecules↗

The interrelation between TNF, IL-6, and PAF secretion induced by LPS in an in vivo and in vitro murine model.

The interrelation between TNF, IL-6, and PAF secretion in an in vivo and in vitro murine model was studied. Mice were injected with LPS, giving rise to considerable TNF and IL-6 serum levels. To determine the influence of TNF production on the IL-6 secretion, one group of mice was treated with an anti-TNF mAb before LPS administration. The LPS-induced IL-6 secretion was reduced to 48% in the anti-TNF-pretreated group. Parallel to the in vivo experiments, cultures of murine peritoneal macrophages were stimulated with LPS. IL-6 secretion was diminished for 25% in presence of anti-TNF mAb. Further, the role of PAF released in response to a challenge with LPS in the regulation of TNF and IL-6 production was investigated. TNF secretion was strongly reduced when cultures of peritoneal macrophages were stimulated with LPS in the presence of a PAF antagonist, whereas IL-6 secretion was not altered by the PAF antagonist. However, pretreatment of mice with a PAF antagonist did not influence serum TNF, nor serum IL-6 levels induced by LPS injection. These data show that TNF was an intermediate in the induction of IL-6 production in vivo and in vitro. PAF played a central role in the TNF release in the in vitro experiments. This could, however, not be established in vivo. LPS-induced PAF secretion was not involved in the regulation of IL-6 secretion.

Animals↗

Evaluation of measurement of human TNF in plasma by ELISA.

The performance of a sandwich-ELISA for TNF measurement in plasma and serum was studied. The ELISA was first statistically analyzed. Interassay coefficient of variance and the intraassay coefficient of variance for the concentration range between 0.5 and 5 ng/ml was less than 10%. The sensitivity of the sandwich-ELISA for TNF in culture medium was 10 pg/ml. The ELISA was shown to be specific for biologically active TNF, since a good correlation between the ELISA and the WEHI bioassay was observed when partially inactive, denatured TNF was measured. The effect of various anticoagulation systems on the reliability of human TNF measurement has been evaluated. The oxalate/NaF and EDTA systems were both appropriate, as appeared from the observed blockade of the production of TNF in the tube, either in the cell-glycolysis-blocked or in the calcium-depleted situation, respectively. An eventual decrease in the recovery of rTNF after collection of blood was prevented in the oxalate/NaF tubes. Recovery of TNF in the ELISA was diminished in the presence of plasma or serum. Techniques to enhance the efficiency of the measurement of TNF in plasma by ELISA were compared. The data indicate that in the presence of 1.1 M NaCl, the TNF masking effect of normal plasma was largely abrogated. The presence and role of inhibiting plasma components in plasma of healthy and diseased individuals are discussed.

Biological Assay↗