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Biomedical subjects

D Scheinichen

Publications and source records attributed to D Scheinichen.

27 records · Page 2Linked to original sources
PubMed1999

Neutrophil respiratory burst following liver transplantation: in vitro effects of granulocyte colony-stimulating factor.

Early postoperative infections and septic complications are predominant causes of morbidity and mortality in patients following orthotopic liver transplantation (OLTx). Prophylactic granulocyte colony-stimulating factor (G-CSF) administration after OLTx was found to decrease the number of sepsis episodes and sepsis-related mortality. Since polymorphonuclear neutrophils (PMNs) are one of the major determinants of antimicrobial defense, alteration of their functions may influence the development of sepsis in these patients. Therefore, we investigated in vitro whether or not priming with G-CSF affects the neutrophils' respiratory burst (RB) in immunosuppressed liver-transplanted patients. Venous blood was drawn from liver allograft recipients (n=12) between the 5th and 15th day postoperatively. Patients without clinical signs of infection or rejection were included in this study. Leukocytes were obtained as supernatant following sedimentation and incubated with 1000 IE ml-1 G-CSF. The RB was measured by the intracellular oxidation of non-fluorescent dihydrorhodamine to the fluorescent rhodamine by flow cytometry. The results were expressed as a percentage of increasing stimulation compared to the control responses, which are made up of the percentage of cells with RB reaction after stimulation with phorbol ester (PMA), bacteria (E. coli), or the combination of a cytokine (TNF-alpha) and a bacterial peptide (FMLP) in the absence of G-CSF. In vitro priming with G-CSF resulted in significantly increased activity of the RB after PMA (from 71.7% to 85.6%) and TNF-alpha/FMLP (from 58.4% to 72.7%) stimulation. These data demonstrate that G-CSF in vitro augments the RB of PMNs, thereby suggesting a possible therapeutic role for G-CSF as immunomodulating agent during bacterial and fungal infections following OLTx.

Flow Cytometry↗
PubMed1999

[Value of the laryngeal mask in emergency care--a survey of North German emergency physicians].

In clinical routine, the laryngeal mask airway (LMA) has proved an alternative to both endotracheal intubation and mask ventilation. In a survey among North German emergency physicians, aspects such as doctors' acquaintance with the LMA, the degree of ist distribution, its use and its potential benefits under non-hospital emergency conditions were evaluated. Seventeen per cent (n = 162) of physicians responded to the questionnaire, 75% of them (n = 122) anaesthetists. Although 73% (n = 119) were familiar with the use of the LMA from clinical experience, and again 73% would welcome having LMA use and application as part of the training of non-academic members of ambulance teams, only 24% (n = 37) of the responding doctors have an LMA on their emergency ambulances and merely twelve (7.4%) physicians reported actually using the LMA, one of them unsuccessfully. Sixty-three per cent considered the LMA the first-choice alternative in an unexpected "can't-ventilate-can't-intubate" situation. Use of the LMA should be extended in emergency medicine especially as its application is relatively easy to learn in clinical routine.

Attitude of Health Personnel↗
PubMed1998

Remifentanil, fentanyl, and alfentanil have no influence on the respiratory burst of human neutrophils in vitro.

BACKGROUND: Anaesthetic agents inhibit certain functions of human neutrophils. The respiratory burst (RB) enzyme in the plasma membrane of neutrophils leads to the production of superoxide anion. The oxygen radicals are responsible for killing phagocytised micro-organisms. We investigated the in vitro influence of remifentanil, fentanyl, and alfentanil on the respiratory burst of human neutrophils. METHODS: For the flow-cytometric evaluation, leukocytes were obtained as supernatant following sedimentation and were incubated with the tested drugs. The concentrations in vitro were adjusted to conform to the plasma concentrations reported for anaesthesia and also to 10-fold higher concentrations. The RB was measured by intracellular oxidation of dihydrorhodamine to fluorescent rhodamine after induction of phorbol-myristate-acetate (PMA), Escherichia coli (E. coli) or priming by tumour necrosis factor alpha followed by stimulation of n-formyl-methionyl-leucyl-phenylalanine (TNF-alpha/FMLP). In order to exclude prestimulation of the neutrophil granulocytes, negative controls were carried out. Propidium iodide (PI) was added for viability discrimination immediately prior to flow cytometry measurement. RESULTS: Regardless of the triggering agents chosen (PMA, E. coli, TNF-alpha/FMLP), remifentanil, fentanyl, and alfentanil had no significant effect on the neutrophils' respiratory burst even in concentrations which were higher than those encountered during in vivo conditions. CONCLUSION: With respect to peri- and postoperative risk of infection, anaesthetics and analgetics with no inhibiting effect on neutrophil function should be used. These results show that remifentanil, fentanyl, and alfentanil do not influence the neutrophils' respiratory burst in vitro.

Alfentanil↗
PubMed1997

Inhibition of neutrophil respiratory burst and chemotaxis in vitro by thiopentone but not methohexitone.

Administration of high-dose barbiturates may be used as an appropriate adjunctive treatment for control of intracranial pressure. The thiobarbiturate, thiopentone, has been reported to increase the rate of nosocomial pulmonary infection. This may be a substance-related effect of thiobarbiturates and it may be clinically important in barbiturate-sedated patients with severe head injury. Thus, the effects of the dose-response relationship of two commonly used barbiturates (thiopentone and methohexitone) on two vital aspects of neutrophil function were tested. We studied the production of superoxide anion during the respiratory burst by means of a flow cytometric method, and we assessed N-formyl-methionyleucylphenylalanine-induced neutrophil chemotaxis using the results produced by specific migration. The concentrations of thiopentone and methohexitone tested in vitro were adjusted to conform to the plasma concentrations reported for anesthesia and also to 10-fold higher concentrations. Only thiopentone dose dependently decreased respiratory burst and N-formyl-methionyleucylphenylalanine-induced chemotaxis. Methohexitone produced minimal effects in both concentrations. It was demonstrated that thiopentone had a direct effect on the intracellular respiratory burst oxidase enzyme system. The postulated free radical scavenging capacity of thiopentone was ruled out.

Journal Article↗
PubMed1997

[Effect of remifentanil on respiratory burst of human neutrophilic granulocytes in vitro].

Recovery chances for severely ill patients have been significantly improved by the progress of intensive care medicine. The success of any therapy, however, is still jeopardized by postoperative infections and septic complications. In the early stage of bacterial infections polymorphonuclear leukocytes (PMNL) play a decisive role. After PMNL activation, the production of oxygen radicals during the respiratory burst (RB) denature the phagocytosed micro-organisms. Remifentanil is a new opioid which has been safely administered to various patient groups and shows pharmacokinetic advantages in comparison to the already established opioids. As some intravenous anaesthetics can influence PMNL functions, we analysed, by flow cytometry, the in vitro influence of clinically relevant remifentanil concentrations on the respiratory burst. In our study remifentanil had no influence on the respiratory burst of human PMNL in vitro, regardless of the RB triggering agents chosen.

Analgesics, Opioid↗
PubMed1996

Flow cytometry evaluation of the in vitro influence of four i.v. anaesthetics on respiratory burst of neutrophils.

Exposure of neutrophils to anaesthetic agents may alter their functional characteristics and in patients undergoing long-term sedation this may be clinically relevant. We have investigated the in vitro influence of propofol, thiopentone, methohexitone and midazolam on phorbol 12-myristate 13-acetate (PMA)-induced respiratory burst of neutrophils by the intracellular oxidative transformation of dihydrorhodamine-123 to the fluorescent dye rhodamine-123 via flow cytometry. We tested in vitro concentrations similar to sedating, anaesthetic, 10-fold sedating and 10-fold anaesthetic plasma concentrations. All drugs showed similar inhibition of respiratory burst at sedating concentrations (1-6%). At anaesthetic concentrations, propofol produced significantly higher mean inhibition (7.3%) compared with thiopentone (4.5%) and methohexitone (0.9%). At 10-fold anaesthetic concentrations inhibition of respiratory burst by propofol was almost complete (90.8%) and significantly higher than that by thiopentone (29.2%) and methohexitone (1.8%). Methohexitone and midazolam had only minimal effects at all concentrations. The effect of the solvent of propofol (10% Intralipid) was similar to that of propofol. Thus suppression of respiratory burst of neutrophils by propofol may be caused by this lipid carrier.

Anesthetics, Intravenous↗
PubMed1993

A constant flux system using the 'magnetic cell separator' (MACS) for highly efficient T-cell depletion.

A method for highly efficient T-cell depletion using a 'Magnetic Cell Separator' (MACS) is described. T-lymphocytes were depleted from peripheral blood samples of 37 patients with chronic lymphocytic leukemia (CLL). The flow speed in the MACS column was adjusted by a syringe-driver allowing a constant flow speed of about 100 microliters/min. The mean content of T-cells after depletion was 0.17% (S.D. +/- 0.27). The effectiveness of depletion was calculated to a mean 93.7%. There was no correlation between the proportion of CD3-positive cells before and after depletion.

CD3 Complex↗
PubMedDate not supplied

In vitro influence of parenteral lipid emulsions on the respiratory burst of neutrophils.

The in vitro effect of a fish oil-derived lipid emulsion (omega-3) on the superoxide anion production during the respiratory burst (RB) of human neutrophils was compared to a LCT lipid (Intralipid), and an LCT/MCT emulsion (Lipofundin MCT). The effects of two concentrations (60 and 600 micrograms/mL) were evaluated by rhodamine in a flow cytometer. The RB was induced either by stimulation with Escherichia coli (E. coli) or by priming with TNF-alpha and FMLP stimulation. The results (mean +/- SD%, P < 0.05) were compared to positive control responses (RB without lipids). omega-3 (60 micrograms/mL, -8.2 [9.3]%; 600 micrograms/mL, -9.6 [11.1]%) and LCT (600 micrograms/mL, -8.0 [9.3]%) significantly suppressed the RB after stimulation with E. coli. LCT/MCT increased the RB after E. coli (60 micrograms/mL, 15.7 [15.4]%; 600 micrograms/mL, 42.7 [21.4]%) as well as after TNF-alpha/FMLP stimulation (600 micrograms/mL, 27.4 [23.7]%). The in vitro influence of parenteral lipid emulsions on the superoxide anion production of human neutrophils is dependent on the length of the fatty acid molecule.

Drug Combinations↗