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Biomedical subjects

J Damen

Publications and source records attributed to J Damen.

At least 19 recordsLinked to original sources
PubMed2004

[Prophylactic perioperative beta-blockade reduces cardiac morbidity and mortality following non-cardiac surgery in patients at risk].

Approximately 5% of all patients undergoing non-cardiac surgery suffer some form of perioperative cardiac morbidity, usually preceded by myocardial ischaemia. In the Netherlands, the cardiac mortality following non-cardiac surgery is 0.68%. The patient groups at risk for cardiac complications are: age 65 years and older, patients with coronary artery disease or risk factors for coronary artery disease, and those undergoing major surgery. The period of greatest risk is the early postoperative phase. Prophylactic beta-blockade significantly reduces perioperative cardiac morbidity and mortality: the odds ratio for myocardial ischaemia is 0.34 (95% CI: 0.23-0.52), for non-fatal myocardial infarction 0.15 (95% CI: 0.06-0.40) and for cardiac mortality 0.25 (95% CI: 0.09-0.73). Long-term continuation of the beta-blockade also reduces cardiac morbidity and mortality in the first two years following the operation.

Adrenergic beta-Antagonists↗
PubMed2003

[Admission and discharge criteria for intensive care departments].

Admission and discharge criteria for intensive care departments have been drawn up in order to optimise the use of scarce and costly intensive care facilities. Every patient who could benefit from admission must be assessed by the intensive care specialist beforehand. Admission is indicated for patients with disrupted vital functions in whom recovery of dysfunctioning or failing organ systems is expected, patients who will act as organ donors and patients who undergo diagnostic investigations associated with a high risk of vital complications. Frequent assessment (several times per day) of the 'indication to stay' is indicated in the case of many patients in order to maximise the admission capacity. Discharge from the intensive care department is indicated if the vital functions are stable without life support and no longer require monitoring or treatment, if nursing the patient in the ward is possible, if continuation of the medical treatment is no longer worthwhile, if the patient no longer consents to the treatment and if the benefit of a treatment no longer outweights its negative effects.

Cost-Benefit Analysis↗
PubMed1998

BCR-ABL accelerates C2-ceramide-induced apoptosis.

In patients with chronic myeloid leukemia (CML), the neoplastic (BCR-ABL+) progenitor cells are characterized by an increased proliferative activity. Whether these cells are also resistant to apoptosis and if so, under what conditions remains controversial. We now show that highly purified populations of very primitive neoplastic progenitor cells obtained directly from CML patients survive and proliferate in vitro for several weeks in the absence of any added growth factors (except insulin). In contrast, purified primary normal progenitors maintained under the same conditions die rapidly. Nevertheless, both primary CML cells and BCR-ABL+ BAF3 cells show the same dose-dependent sensitivity to TNF-alpha or ceramide-induced apoptosis as their respective normal counterparts. In fact, time course studies demonstrated an even faster onset of apoptosis in ceramide-treated BCR-ABL+ BAF3 cells as compared to normal controls. BCR-ABL+ cells treated with ceramide also showed a rapid and sequential increase in the tyrosine phosphorylation of p210(BCR-ABL), p46-56SHC and p120Cbl. These findings suggest growth factor deprivation and treatment with TNF-alpha or ceramide trigger different initial events both of which can lead to apoptosis in factor-dependent hematopoietic cells. However, in the first case, activation of apoptosis is blocked by the basal activity of p210(BCR-ABL), whereas in the second, the presence of p210(BCR-ABL) appears to accelerate the onset of apoptosis by a mechanism that may involve an activation of its kinase function.

Apoptosis↗
PubMed1995

Reduction of reperfusion injury of human myocardium by allopurinol: a clinical study.

To determine the possibility of myocardial protection against reperfusion injury by allopurinol, 22 aortocoronary bypass patients were studied. Eight patients received allopurinol (200 mg during induction of anesthesia and 100 mg after starting extracorporeal circulation) during surgery (group B), and 14 patients served as a control (group A). Blood samples and myocardial biopsies were taken before and 10 min after aortic cross-clamping. No statistically significant difference between the two groups was observed considering gender, age, prior myocardial infarction, left ventricular end diastolic pressure (LVEDP), and aortic cross-clamp time. Preservation of cardiac tissue was assessed by the measurement of quantitative birefringence (QBR) changes upon the addition of adenosine 5'-triphosphate (ATP) plus calcium in biopsies and the need for postoperative inotropes. The synthesis of peroxides was estimated by the measurement of leukotriene B4 and C4 (LTB4, LTC4). LTB4 was below the level of detection (< 1.5 ng/l) before and after cross-clamping in both groups, while the LTC4 level for group A increased from < 1.5 to 27 +/- 17 ng/l compared to an increase of < 1.5 to 11 +/- 8 ng/l for group B after 10 min of reperfusion (p = .036). The decrease in QBR value in group A was 1.26 +/- 0.28 and 0.35 +/- 0.23 for group B (p < .003). Postoperatively, 11 out of 14 patients in group A needed inotropic support (dopamine or dobutamine), whereas two patients out of eight did so in group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1993

Disconnection of the ventilatory system does not prevent pleural lesions during sternotomy.

In previous studies pleurotomy has seldom been reported as a complication of sternotomy and, therefore, the incidence is unknown. Factors increasing or decreasing the risk of pleurotomy also have not been studied properly. In a prospective, randomized trial, performed during 14 consecutive months from 1988 until 1989, the incidence of pleurotomy and its possible risk factors were studied in 712 patients undergoing median sternotomy for cardiac and mediastinal procedures. The overall incidence of pleurotomy was 14.7%. Chronic obstructive pulmonary disease, the use of positive end-expiratory pressure, and continuation or discontinuation of the ventilatory system did not affect the incidence. A surgeon-related risk factor could be significantly identified (P < 0.001). In conclusion, disconnection of the ventilatory system during sternotomy has been shown to have no influence on the pleurotomy rate and its continued use is no longer valid.

Aged↗
PubMed1992

Erythropoietin-induced tyrosine phosphorylations in a high erythropoietin receptor-expressing lymphoid cell line.

Retroviral gene transfer of the murine erythropoietin receptor (EpR) cDNA into the pro-B-cell line, Ba/F3, was used to generate cells expressing high EpR levels. One of the resulting clones, Ba/F3 clone C5, contained 5 integrated copies of the gene and expressed, at the cell surface, a single affinity class of EpRs at 10 to 15 times the level present on spleen cells from phenylhydrazine-treated mice. Cross-linking studies with clone C5, using 125I-Ep, yielded the same two 105- and 88-Kd major species as that seen with typical erythroid cells. This was distinct from that obtained with EpR-transfected COS cells or L cells, which gave species of 88 and 65 Kd. This suggests that the biologically active EpR complex generated in this Ba/F3 cell line may closely resemble that present in native Ep-responsive erythroid progenitor cells. Tyrosine phosphorylation experiments showed that several proteins in clone C5 cells were rapidly phosphorylated on tyrosine residues in response to Ep, one being the EpR itself. The proportion of cell surface EpRs tyrosine phosphorylated in response to Ep was substantial, reaching a maximum of approximately 10% within 30 minutes of incubation at 37 degrees C. A comparison of Ep- and murine interleukin-3 (mIL-3)-induced tyrosine phosphorylation patterns in clone C5 cells showed that both growth factors stimulated the tyrosine phosphorylation of proteins with molecular weights of 135, 93, 70, and 55 Kd. This could suggest that the Ep and mIL-3 receptors are capable of using the same tyrosine kinase in these cells.

Animals↗
PubMed1989

Acute hemodynamic effects of pericardial closure in man.

The acute hemodynamic effects of pericardial closure were studied in 30 patients with normal left ventricular function, who were undergoing coronary artery bypass surgery. Closure of the pericardium resulted in decreases in arterial blood pressure (P less than 0.01), cardiac index (P less than 0.001), mean right atrial (P less than 0.001), mean pulmonary artery (P less than 0.001) and pulmonary capillary wedge pressure (P less than 0.001). The observed hemodynamic changes are probably caused by a change in the ventricular pressure-volume relationships.

Blood Pressure↗
PubMed1988

Effect of dietary lipids on plasma lipoproteins and fluidity of lymphoid cell membranes in normal and leukemic mice.

Mice of the GR/A strain were fed four different isocaloric semipurified diets, enriched in either (1) saturated fatty acids (palm oil), or (2) polyunsaturated fatty acids (corn oil), or (3) palm oil plus cholesterol, or (4) a fat-poor diet containing only a minimal amount of essential fatty acids. We have studied the effects of these dietary lipids on the density profile and composition of the plasma lipoproteins and on the lipid composition and fluidity of (purified) lymphoid cell membranes in healthy mice and in mice bearing a transplanted lymphoid leukemia (GRSL). Tumor development in these mice occurred in the spleen and in ascites. While the fatty acid composition of the VLDL-triacylglycerols still strongly resembled the dietary lipids, the effects of the diets decreased in the order VLDL-triacylglycerols greater than HDL-phospholipids greater than plasma membrane phospholipids. Diet-induced differences in the latter fraction were virtually confined to the content of oleic acid and linoleic acid, and they were too small to affect the membrane fluidity, as measured by fluorescence polarization using the probe 1,6-diphenyl-1,3,5-hexatriene. Healthy mice were almost irresponsive to dietary cholesterol, but in the tumor bearers, where lipoprotein metabolism has been shown to be disturbed, the cholesterol diet caused a substantial increase in the low- and very-low density regions of both blood and ascites plasma lipoproteins. The cholesterol-rich diet also increased the cholesterol/phospholipid molar ratio and lipid structural order (decreased fluidity) in GRSL ascites cell membranes, but not in the splenic GRSL cell membranes. We conclude that the composition of plasma lipoproteins and cell membrane lipids in GR/A mice is subject to exquisite homeostatic control. However, in these low-responders to dietary lipids the development of an ascites tumor may lead to increased responsiveness to dietary cholesterol. The elevated level of membrane cholesterol thus obtained in GRSL ascites cells did not affect the expression of various cell surface antigens or tumor cell growth.

Animals↗
PubMed1988

The microbiologic risk of invasive haemodynamic monitoring in open-heart patients requiring prolonged ICU treatment.

The microbiologic risk of invasive haemodynamic monitoring and support was prospectively studied in 48 patients undergoing open-heart surgery under antibiotic prophylaxis and requiring intensive care for longer than 4 days. A total of 420 catheter tips were cultured of which 12 (2.9%) were positive. The incidence of positive catheter tip cultures was as follows: intravenous 1.8%, central venous 1.2%, arterial 1.8%, pulmonary arterial 5.9%, direct right atrial 2.4%, direct left atrial 0% and intra-aortic balloon pump catheters 7.7%. The rate of positive tip cultures was not significantly different for percutaneously and surgically inserted catheters (3.1% and 1.7% respectively). One (0.2%) catheter was associated with bacteraemia. Although the overall positive catheter tip culture rate was low, 21% of the patients had one or more positive catheter tip cultures. Complicated surgical procedures, a cardiopulmonary bypass time longer than 3.5 h, mechanical ventilation for more than 7 days, intensive care stay longer than 10 days, positive blood cultures and the use of more than 20 catheters were all individually associated with a significantly higher incidence of patients with positive tip cultures. Nevertheless, no patient developed endocarditis nor major morbidity related to the positive catheter tip cultures. Invasive haemodynamic monitoring does not seem to be an important microbiologic risk in open-heart patients requiring intensive care for longer than 4 days.

Adult↗
PubMed1988

Positive tip cultures and related risk factors associated with intravascular catheterization in pediatric cardiac patients.

The incidence and risk factors of positive catheter tip cultures were studied prospectively in 392 consecutive children undergoing cardiac surgery under cover of cephalothin prophylaxis. A total of 1649 catheter tips were cultured and 58 (3.5%) yielded positive cultures. Specifically, the incidence of positive catheter tip cultures for iv, central venous, arterial and pulmonary arterial (PA) catheters was 0.9%, 5.9%, 3.9% and 10.6%, respectively, whereas one of the six surgically placed venous and arterial catheters had a positive tip culture and none of the 279 transthoracic catheters. Staphylococcus epidermidis was isolated from 79% of the positive tip cultures. Ten percent of the children had one or more positive tip cultures but none developed catheter-related septicemia or endocarditis. Stepwise logistic regression analysis revealed that longer in situ time (p less than .001), younger age (p less than .001), and inotropic support (p = .003) were significant independent predictors of risk for children developing positive catheter tip cultures. The safe in situ period for arterial, central venous, and PA catheters is 3 days in infants under 1 yr and 4 and 6 days for arterial and central venous catheters, respectively, in older children, if 0.95 cumulative probability of remaining free of a positive tip culture is accepted. The data generally support the bacteriologic safety of invasive hemodynamic monitoring in infants and children undergoing cardiac surgery.

Adolescent↗
PubMed1987

The use of balloon-tipped pulmonary artery catheters in children undergoing cardiac surgery.

Percutaneous pulmonary artery (PA) catheterization via the internal jugular vein was studied in 58 children undergoing cardiac surgery. Central venous cannulation, which succeeded in all children, was associated with a 10% incidence of inadvertent carotid artery puncture without untoward effects. Successful placement of the PA catheter was achieved in 47 (92%) of the 51 children in whom it was anatomically possible to enter the pulmonary artery at the time of the catheterization. Four (8%) catheter tip cultures were positive. The PA catheter yielded important information in diagnosing low cardiac output, severe pulmonary hypertension or residual cardiac defects in 27 (47%) children. Twenty (35%) children had critical therapeutic interventions because of the PA catheter information. The high yield of important data and the low incidence of major complications seem to justify the use of percutaneously inserted PA catheters in children with an increased operative risk.

Cardiac Surgical Procedures↗
PubMed1987

Infectious complications of simultaneously inserted central venous and pulmonary artery catheters.

Infectious complications associated with simultaneously inserted pulmonary artery and central venous catheters via the same internal jugular vein were studied prospectively in 622 patients undergoing open-heart surgery under cephalothin prophylaxis. Successful insertion of the catheters was achieved in 650 (98.3%) of 661 attempts, while puncture complications occurred in 51 (8.2%) patients. One (0.2%) patient developed a local infection and 24 (3.9%) patients had one or more positive catheter-tip cultures without complications related to the positive cultures. Patients with puncture complications had no significantly different incidence of positive tip cultures. The incidence of positive catheter-tip cultures for pulmonary artery and central venous catheters was 2.6% and 1.7% respectively. Monitoring with a pulmonary artery and central venous catheter inserted via the same internal jugular vein is associated with a low rate of infectious complications.

Adult↗
PubMed1986

The microbiological risk of invasive hemodynamic monitoring in adults undergoing cardiac valve replacement.

The microbiological risk of invasive hemodynamic monitoring was studied prospectively in 230 consecutive patients undergoing cardiac valve replacement during prophylactic therapy with cephalothin. A total of 923 catheter tips were cultured, and 1.6% yielded positive cultures. The rate of positive cultures did not differ significantly between catheters inserted percutaneously (1.9% positive) and those inserted surgically (0.5% positive). The incidence of positive catheter tip cultures for intravenous, central venous, arterial, and pulmonary arterial catheters was 0, 1.5, 2.6, and 2.9%, respectively, whereas the surgically inserted right and left atrial catheters yielded 0.6 and 0% positive tip cultures, respectively. One patient developed septicemia related to a right atrial catheter. There was no correlation between the incidence of positive catheter tip cultures and the length of time that the catheters remained in situ. No patient developed early or late endocarditis. Invasive hemodynamic monitoring seems to be microbiologically safe, even in patients undergoing cardiac valve replacement.

Adult↗