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Biomedical subjects

C Grube

Publications and source records attributed to C Grube.

10 recordsLinked to original sources
PubMed2002

[Man at risk. Preventive strategies and risk management for patient safety].

Anaesthesia-related risk has been significantly reduced within the last decade. Nevertheless the risk and the possibility of dying or suffering permanent damage still exist. To improve patient safety, risk assessment and analysis must lead to the development of preventive strategies. For this purpose anaesthesia can rely on the concepts of other "high reliability" organisations such as aviation or nuclear power plants. Analyses of critical incidents in the different fields confirm that next to technical problems human factors account for most of the preventable mishaps. Human factors are responsible for individual mistakes as well as for organisational errors. Therefore besides traditional concepts of risk reduction (e.g. guidelines) new strategies (e.g. full-scale simulation) must be applied to minimise the negative impact of human factors on patient safety. Risk management has to consider technical, organisational and human factors to implement a higher standard of patient safety.

Anesthesia↗
PubMed2001

N-acetylcysteine induces shedding of selectins from liver and intestine during orthotopic liver transplantation.

In orthotopic liver transplantation (OLT), N-acetylcysteine (NAC) reduces ischaemia/reperfusion (I/R) injury, improves liver synthesis function and prevents primary nonfunction of the graft. To further elucidate the mechanisms of these beneficial effects of NAC, we investigated influence of high-dose NAC therapy on the pattern of adhesion molecule release from liver and intestine during OLT. Nine patients receiving allograft OLT were treated with 150 mg NAC/kg during the first hour after reperfusion; 10 patients received the carrier only. One hour after reperfusion, samples of arterial, portal venous and hepatic venous plasma were taken and blood flow in the hepatic artery and the portal vein was measured. Absolute concentrations of sICAM-1, sVCAM-1, sP-selectin and sE-selectin were not markedly different. However, balance calculations showed release of selectins from NAC-treated livers as opposed to net uptake in controls (P < or = 0.02 for sP-selectin). This shedding of selectins might be a contributing factor to the decrease in leucocyte adherence and improved haemodynamics found experimentally with NAC-treatment.

Acetylcysteine↗
PubMed1993

Proteolytic cleavage of fibrinogen: amplification of its surfactant inhibitory capacity.

Severe deterioration of surfactant function is noted under conditions of plasma protein leakage into the alveolar space; moreover, fibrinogen has previously been reported to possess strong surfactant inhibitory capacity. Dissolution of alveolar deposits of fibrinogen and fibrin (e.g., hyaline membranes) requires enzymatic degradation by the plasminogen/plasmin system or by leukocyte-derived proteases. We investigated the surfactant inhibitory properties of differently prepared sets of fibrinogen cleavage products. Proteolysis was performed with plasmin, with predominant split products D (mol wt 85,000) and E (mol wt 50,000). In addition, fibrinogen was cleaved by leukocyte elastase and trypsin, with fragments ranging mainly between mol wt of 30,000 and 50,000. To provide split products of even lower molecular weight, fibrinogen was incubated sequentially with trypsin and endoproteinase (split products < mol wt 25,000). Natural surfactant extracts used in clinical replacement studies (CLSE, Alveofact, Curosurf, Survanta) as well as an apoprotein-based phospholipid mixture (PLM-C/B; DPPC:PG:PA = 68.5:22.5:9 with 2% [wt/wt] nonpalmitoylated recombinant human SP-C and 1% [wt/wt] natural bovine SP-B) were employed. Experiments were performed in a pulsating bubble surfactometer (standard phospholipid concentration 2 mg/ml) with assessment of surfactant activity measuring adsorption and dynamic surface tension. Fibrinogen caused dose-dependent, severe deterioration of the surface activities of Curosurf and Survanta, whereas CLSE, Alveofact, and PLM-C/B were only moderately affected up to protein-surfactant ratios of 4:1.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

Surfactant inhibition by plasma proteins: differential sensitivity of various surfactant preparations.

Leakage of plasma proteins into the alveolar space may inhibit surfactant function. We compared the surface properties and the sensitivity to inhibitory proteins of different organic solvent surfactant extracts and a synthetic surfactant. Experiments were performed in the pulsating bubble surfactometer, with surfactant concentrations ranging between 0.1 and 2 mg.ml-1. Inhibition profiles towards fibrinogen, albumin and haemoglobin were obtained from calf lung surfactant extracts (CLSE), Alveofact, Curosurf and Survanta (all used in clinical, replacement studies in respiratory distress syndrome (RDS) and of an apoprotein-based synthetic phospholipid mixture (PLM-C/B; DPPC:PG:PA = 68.5:22.5:9, supplemented with 2% wt/wt non-palmitoylated human recombinant SP-C and 1% t/wt natural bovine SP-B). In the absence of inhibitory proteins, all surfactants exhibited dose-dependent rapid adsorption (rank order of relative efficacy PLM-C/B = CLSE > Alveofact > Curosurf > Survanta). Minimal surface tension was reduced to near zero values under dynamic compression (rank order PLM-C/B > CLSE > Alveofact = Curosurf) and to approximately 4 mN.m-1 (Survanta). Curosurf and Survanta were dose-dependently inhibited by fibrinogen > haemoglobin > albumin, with far-reaching loss of surface activity at protein-surfactant ratios above 1:1. In contrast, CLSE and Alveofact were only moderately inhibited by fibrinogen, and were not affected by haemoglobin and albumin, up to protein-surfactant ratios of 2:1. PLM-C/B exhibited resistance to fibrinogen, intermediate sensitivity to albumin, and was severely inhibited by haemoglobin. We conclude that various natural surfactant extracts and an apoprotein-based synthetic surfactant mixture markedly differ in their sensitivity to inhibitory plasma proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Surface properties and sensitivity to protein-inhibition of a recombinant apoprotein C-based phospholipid mixture in vitro--comparison to natural surfactant.

Surfactant alterations due to protein leakage are implicated in the pathogenesis of the adult respiratory distress syndrome. In the present study, surface properties of a palmitic acid containing phospholipid mixture (DPPC: PG: PA/68.5:22.5:9) supplemented with 2% recombinant human surfactant apoprotein C (PLM-Crec) were compared to those of the lipids alone (PLM) and to those of calf lung surfactant extract (CLSE). Experiments were performed in a Wilhelmy balance and in a pulsating bubble surfactometer. Adsorption facilities and dynamic surface tension-lowering properties of the surfactants alone, their sensitivity to the inhibitory effect of fibrinogen (fbg), and their capacity to restore surface properties of fbg-inhibited CLSE were investigated. PLM revealed limited surface activity, was very sensitive to inhibition by fbg and had moderate effect on the surface properties of fbg-inhibited CLSE. In contrast, PLM-Crec and CLSE revealed similar excellent adsorption kinetics and dynamic surface tension lowering properties. Higher percentage of SP-C within the synthetic mixture (up to 10%) or additional admixture of human purified or recombinant SP-A (up to 10%) did not further improve these surface properties. However, PLM-Crec was markedly more sensitive to inactivation by fbg than CLSE. The surface activity of fbg-inhibited CLSE was fully restored by additional admixture of CLSE or PLM-Crec in both the Wilhelmy and the bubble system, with slight superiority of the natural surfactant extract. We conclude that the surface properties of PLM-Crec are clearly superior to those of the apoprotein-free lipid mixture and are similar to those of the natural surfactant extract CLSE. PLM-Crec is markedly more sensitive to inhibition by fibrinogen than CLSE, but possesses nearly equivalent efficacy in restoring the surface properties of fbg-inhibited CLSE as compared to the natural material.

1,2-Dipalmitoylphosphatidylcholine↗