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Biomedical subjects

J Damen

Publications and source records attributed to J Damen.

At least 37 records · Page 2Linked to original sources
PubMed1986

A prospective analysis of 1,400 pulmonary artery catheterizations in patients undergoing cardiac surgery.

During 1983 and 1984, 1305 patients underwent 1,400 pulmonary artery (PA) catheterizations. Successful placement was achieved in 1397 (99.6%) of 1,403 attempts. The catheters were inserted via the right internal jugular vein on 1364 occasions. The median duration of monitoring was 28 h with a range from 3 to 220 h. Central venous puncture complications included carotid artery puncture in 67 instances (4.8%) and pneumothorax in one patient. Insertion of the catheters was associated with supraventricular arrhythmias on 11 occasions, ventricular arrhythmias on 930 (66.4%), right bundle branch block on two and a total heart block on one occasion. Eighteen (2.3%) of the 794 cultured catheter tips were positive. An in situ time of more than 72 h was associated with a significantly higher percentage (7.2%) of positive tip cultures compared with an in situ time of less than 72 h (P less than 0.01). Repeated PA catheterization was not associated with significantly more complications than the initial catheterization. The results show that monitoring with a PA catheter in cardiac surgical patients is associated with a low incidence of morbidity.

Arrhythmias, Cardiac↗
PubMed1985

Alterations in biosynthesis and homeostasis of cholesterol and in lipoprotein patterns in mice bearing a transplanted lymphoid tumor.

The membrane fluidity of murine lymphoid GRSL tumor cells has been shown to depend on their site of growth in the host. Tumor cells located in ascites, in contrast to those in the enlarged spleen, show a very high plasma membrane fluidity, mainly due to a decreased level of cellular (membrane) cholesterol. Yet, the rate of cholesterol biosynthesis in the tumor cells as estimated by the activity of HMG-CoA reductase and the incorporation of [14C]acetate into cholesterol was extremely high when compared to various lymphoid cells in normal control mice. Also the rate of biosynthesis and the cholesterol content in liver and spleen of tumor-bearing mice were substantially higher than in the organs of control mice. Blood plasma cholesterol, however, was decreased in tumor-bearing mice as a result of altered lipoprotein patterns. Outgrowth of the tumor was accompanied by a strong reduction in plasma high-density lipoproteins. Low-density lipoproteins became transiently increased, but eventually all lipoproteins, and consequently the plasma cholesterol content decreased to very low levels, especially so in the ascites plasma. The low transfer of [14C]cholesteryl ester-labeled lipoproteins between blood and ascites plasma after either intravenous or intraperitoneal injection suggested a hampered flow between the two compartments. Also apparent differences in cholesteryl ester fatty acid composition between lipoproteins of the blood and ascites plasma indicated the lack of a rapid equilibration between the two compartments. The results suggest that the limited availability of lipoproteins as an additional source of cholesterol to the rapidly growing ascites cells promotes their high membrane fluidity.

Acetates↗
PubMed1985

Accumulation of HDL-like lipoproteins in the plasma low-density fractions of tumor-bearing mice.

Outgrowth of the transplanted GRSL lymphoma in GR mice yielded several-fold increased blood plasma levels of low- and very-low-density lipoproteins, while high-density lipoproteins were strongly reduced. Changes in cholesteryl ester fatty acid profiles indicated an accumulation of HDL-like particles rather than LDL in the low-density fractions. By intravenous injection of [14C]cholesteryl ester-labeled HDL into tumor-bearing mice, conversion of HDL into lipoproteins of low density was demonstrated.

Animals↗
PubMed1985

Microbiologic risk of invasive hemodynamic monitoring in patients undergoing open-heart operations.

The microbiologic risk of invasive hemodynamic monitoring was studied prospectively in 574 patients undergoing open-heart surgery under cover of cephalothin prophylaxis. Of a total of 2277 catheters inserted in these patients, 1.5% yielded positive cultures. The rate of positive cultures was not significantly different between percutaneous and surgically placed catheters (1.7% vs. 0.8%, respectively). Specifically, the incidence of positive catheter tips for intravenous, central venous, arterial, and pulmonary artery catheters was 1.1%, 3.9%, 1.5%, and 2.1%, respectively; while the corresponding rates for surgically inserted right atrial and left atrial catheters were 0.8% and 0, respectively. Pulmonary artery catheters had a significantly (p less than .01) higher incidence of positive catheter tips after 72 h in situ. However, there was no relationship between the in situ time and the incidence of positive tips for arterial and intravenous catheters. Although the rate of positive catheter tip cultures was low, it affected 4.9% of the patients. Nevertheless, no patient developed catheter-related septicemia or endocarditis, and the data generally supported the microbiologic safety of invasive hemodynamic monitoring in patients undergoing open-heart surgery.

Bacterial Infections↗
PubMed1985

The effect of high-dose fentanyl anaesthesia on P50 in man.

The effect of high dosage fentanyl anaesthesia on P50 was studied in patients undergoing coronary bypass surgery. After induction of fentanyl anaesthesia 100 micrograms X kg-1 with pancuronium muscle relaxation P50 changed significantly (P less than 0.005) from 3.40 +/- 0.12 to 3.33 +/- 0.13 kPa. This anaesthesia technique decreases P50 in vivo, but this has more theoretical than practical importance.

Aged↗
PubMed1985

Ventricular arrhythmias during insertion and removal of pulmonary artery catheters.

The incidence and significance of the development of ventricular arrhythmias during insertion and removal of pulmonary artery monitoring catheters were determined in stable postcardiac surgical patients. Insertion of 173 (69 percent) of 250 catheters was associated with ventricular arrhythmias and removal in 158 (63 percent) of these catheters (p greater than 0.05). All arrhythmias resolved spontaneously. Patients who underwent valve replacement showed significantly fewer arrhythmias during withdrawal than those who underwent a coronary artery bypass operation (p less than 0.025). Factors significantly influencing the incidence of ventricular arrhythmias during removal were increased postoperative CK-MB levels (p less than 0.025) and cardiac index (p less than 0.025).

Adult↗
PubMed1984

Alterations in plasma lipoproteins and heparin-releasable lipase activities in mice bearing the GRSL ascites tumor.

The lipoproteins in GR mice bearing the transplanted GRSL ascites tumor were characterized by density gradient ultracentrifugation and SDS-polyacrylamide gel electrophoresis. In control mice the major proportion of the lipoproteins was found in the HDL density range, but on days 4 and 5 following tumor transplantation a gradual shift into the LDL density range was observed. At the same time the apolipoprotein E content increased at the expense of apolipoprotein A-I. VLDL became moderately elevated. On days 6 and 7 all lipoproteins except VLDL reached extremely low values. The C-apolipoproteins showed a remarkable shift in their relative proportions. Plasma lecithin:cholesterol acyltransferase activity showed no significant alteration in the course of tumor growth, but the triacylglycerol lipases in postheparin plasma were strongly decreased. Lipoprotein lipase had already started to decline on day 2 following tumor transplantation. However, when assayed in the presence of heat-inactivated control plasma, a decrease was not observed before day 5. This is suggestive of a depletion of a plasma cofactor preceding the final disappearance of the enzyme itself, and is compatible with the changing apolipoprotein C pattern. Hepatic lipase showed a 50% reduction between days 3 and 4. The lipoprotein alterations in tumor-bearing mice are explained as a direct consequence of the decreased lipase activities.

Animals↗
PubMed1983

Exchange of phosphatidylcholine between small unilamellar liposomes and human plasma high-density lipoprotein involves exclusively the phospholipid in the outer monolayer of the liposomal membrane.

By making use of the capacity of phospholipase A2 to degrade selectively the phospholipid in the outer half of the lipid bilayer of small unilamellar phospholipid/cholesterol vesicles without affecting the retention of a vesicle-encapsulated solute, we demonstrated that the exchange of phosphatidylcholine between such vesicles and human high density lipoprotein involves exclusively the phosphatidylcholine present in the outer monolayer of the vesicle membrane.

Carbon Radioisotopes↗
PubMed1982

Transfer of [14C]phosphatidylcholine between liposomes and human plasma high density lipoprotein. Partial purification of a transfer-stimulating plasma factor using a rapid transfer assay.

A simple method was developed for the rapid determination of [14C]phosphatidylcholine transfer from small unilamellar liposomes to human plasma HDL, based on the selective precipitation of liposomes by heparin and MnCl2. The assay was utilized to monitor the progress in the partial purification of a phospholipid transfer factor from human plasma. The purification procedure included ultracentrifugation at d = 1.25 g/ml, hydrophobic chromatography on phenyl-Sepharose, affinity chromatography on heparin-Sepharose and gel filtration. The partially purified protein(s) catalyzed the net transfer of phospholipid from small unilamellar phosphatidylcholine liposomes to isolated HDL. The transfer of [14C]phosphatidylcholine from liposomes consisting of phosphatidylcholine/phosphatidylserine/cholesterol (molar ratio, 4:1:5) to HDL was stimulated without affecting the permeability barrier of the liposomal membranes and is, therefore, taken to represent exchange with HDL phospholipid rather than net transfer.

Carrier Proteins↗
PubMed1982

Bradykinin-mediated hypotension after infusion of plasma-protein fraction.

In patients who required volume expansion during extracorporeal circulation, the plasma bradykinin concentration was monitored simultaneously with the mean arterial pressure during infusion of either albumin solution or PPF. The PKA content of the PPF and the albumin solution was 29 and 3 U/L, respectively, measured spectrophotometrically. In six patients receiving 250 ml of PPF, the mean arterial pressure decreased 22% to 54% within 1.5 min after infusion, whereas the plasma bradykinin concentration, measured by radioimmunoassay, increased significantly (p less than 0.0005) during the first minute. In six patients receiving 250 ml of 4% albumin solution, no blood pressure changes were found, and the plasma bradykinin concentration rose only slightly. In vitro, linear correlation (r = 0.94, p less than 0.0005) was observed between the level of PKA of 26 different lots of PPF and the concentrations of bradykinin that were generated in Hageman factor-deficient plasma after incubation with PPF. It is concluded that the hypotensive reactions observed after PPF infusion during extracorporeal circulation are caused by the PKA-induced bradykinin generation.

Adult↗
PubMed1980

Effect of lipoprotein-free plasma on the interaction of human plasma high density lipoprotein with egg yolk phosphatidylcholine liposomes.

Liposomes consisting of 14C-labeled egg yolk phosphatidylcholine were incubated with whole human plasma or plasma subfractions. The transfer of liposomal phospholipid to plasma high density lipoprotein was determined by gel filtration. Whole plasma degraded the liposomes considerably faster than isolated high density lipoprotein. The phospholipid-transferring activity of whole plasma could be recovered in an equivalent mixture of isolated high density lipoprotein and lipoprotein-free plasma. The transfer stimulating activity in lipoprotein-free plasma was not associated with albumin but with a component of higher molecular weight. Upon incubation of lipoprotein-free plasma with liposomes this component appeared to be adsorbed to the liposomes and could thus be separated from the bulk protein by gel filtration. This binding to liposomes is taken as an indication that the component acts by modifying the lipid-water interface thus facilitating the insertion of the lipoprotein into the liposomal bilayer.

Biological Transport↗
PubMed1980

Inhibition of the hypotensive effect of plasma protein solutions by C1 esterase inhibitor.

The hypotensive effect of stable plasma protein solution (SPPS) is a well-known phenomenon, causing serious problems in surgical patients and patients supported by cardiopulmonary bypass. Kinins are believed to be responsible. A study was made to prevent this hypotension by adding C1 esterase inhibitor to the SPPS and comparing this with 5% human albumin. The results shows a significant difference between the effects of SPPS and SPPS plus C1 esterase inhibitor infusion on bypass. Five percent human albumin did not cause hypotension. Possible sequelae are discussed.

Blood Pressure↗