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Biomedical subjects

O Wagner

Publications and source records attributed to O Wagner.

At least 37 records · Page 2Linked to original sources
PubMed2001

Collagen versus gelatin-coated Dacron versus stretch polytetrafluoroethylene in abdominal aortic bifurcation graft surgery: results of a seven-year prospective, randomized multicenter trial.

BACKGROUND: A prospective randomized multicenter trial was performed to compare knitted gelatin-coated Dacron bifurcation grafts, knitted collagen-coated Dacron grafts, and stretch polytetrafluoroethylene (PTFE) grafts. METHODS: Between 1991 and 1998, 315 elective patients were randomized by age, gender, diabetes, runoff, indication (aneurysm, aortoiliac occlusive disease), and nicotine consumption at 3 centers of vascular surgery in Austria. The patients received gelatin-coated Dacron (GEL-D) grafts (n = 109), collagen-coated Dacron (COL-D) grafts (n = 100), or stretch PTFE grafts (n = 106). RESULTS: No intraoperative deaths occurred. The 30-day mortality was 3%. No difference was found between the 3 graft materials in long-term patency. The primary 5-year patency rates were 92% for GEL-D, 89% for COL-D, and 91% for stretch PTFE (P =.6001). The secondary 5-year patency rates also differed: 97% for GEL-D, 100% for COL-D, and 97% for stretch PTFE (P =.2062). Early occlusions were observed overall in 3% and late occlusions in 5% of patients. When both Dacron grafts were compared collectively with stretch PTFE, a difference was found in infection rate: Dacron 3% (6/209) versus PTFE 0% (0/106); P <.03. CONCLUSIONS: The bifurcation grafts of all 3 materials were comparable in primary and secondary patency rates, incidence of false aneurysms, and rate of perioperative complications. Graft infections were confined to the 2 Dacron grafts and did not occur in stretch PTFE grafts.

Aorta, Abdominal↗
PubMed2001

Heme oxygenase-1 gene promoter microsatellite polymorphism is associated with restenosis after percutaneous transluminal angioplasty.

PURPOSE: To determine if an association exists between postdilation restenosis and heme oxygenase-1 (HO-1), which is induced by balloon injury and inhibits neointimal formation through the action of endogenous carbon monoxide. A dinucleotide repeat in the promoter region of the HO-1 gene shows a length polymorphism that modulates the level of gene transcription. METHODS: This cohort study included 96 consecutive patients (64 men; median age 69 years, interquartile range 60-75) who underwent successful balloon dilation in the femoropopliteal segment. Six-month patency was evaluated using oscillography, ankle-brachial index, and duplex sonography. The association of patency and the length of (GT) repeats in the HO-1 gene promoter was assessed in univariate and multivariate analyses. RESULTS: Restenosis was found in 23 (24%) patients within the first 6 months. Patients with short (<25 GT) dinucleotide repeats in the HO-1 gene promoter on either allele had restenosis significantly less often than patients with longer (> or = 25 GT) dinucleotide repeats (p = 0.01). Multivariate analysis revealed a significantly reduced risk for restenosis in these patients compared to patients without the short allele (odds ratio 0.2, 95% Cl 0.06 to 0.70, p = 0.007). CONCLUSIONS: Genetic risk factors for restenosis after percutaneous transluminal angioplasty have not been investigated. In this patient population, short repeat alleles of the heme oxygenase-1 gene promoter polymorphism were associated with reduced postdilation restenosis at 6 months. Upregulation of HO-1 may be an important protective factor after balloon angioplasty by inhibition of vascular smooth muscle cell proliferation.

Aged↗
PubMed2001

Aldolase-localization in cultured cells: cell-type and substrate-specific regulation of cytoskeletal associations.

The role of aldolase as a true F- and G-actin binding protein, including modulating actin polymerization, initiating bundling, and giving rise to supramolecular structures that emanate from actin fibrils, has been established using indirect immunofluorescence, permeabilization of XTH-2 cells and keratocytes, and microinjection of fluorescence-labeled aldolase. In addition, binding to intermediate filaments, vimentin, and cytokeratins has been demonstrated. In permeabilized cells in the presence of fructose-1,6-bisphosphate (20-2000 microM) aldolase shifts from association with actin fibres to intermediate filaments. Plenty of free binding sites on microtubules have been revealed by addition of fluorochromed aldolase derived from rabbit skeletal muscle. However, endogenous aldolase was never found associated with microtubules. Differences in actin polymerization in the presence of aldolase as revealed by pyrene-labeled actin fluorimetry and viscosimetry were explained by electron microscopy showing the formation of rod-like structures (10 nm wide, 20-60 nm in length) by association of aldolase with G-actin, which prevents further polymerization. Upon the addition of fructose-1,6-bisphosphate, G-actin-aldolase mixture polymerizes to a higher viscosity and forms stiffer filaments than pure actin of the same concentration.

Actins↗
PubMed2001

[INR self-management after mechanical heart valve replacement: ESCAT (Early Self-Controlled Anticoagulation Trial)].

Severe thromboembolic and hemorrhagic complications following mechanical heart valve replacement essentially occur due to intense oral anticoagulation and fluctuating individual INR values around the target range. INR self-management can help to minimize these fluctuations. Beginning this therapeutic control immediately after mechanical heart valve replacement further reduces anticoagulant-induced complications. Included in the study were 1200 patients. The quality of oral anticoagulation also improved through INR self-management. Over an observation period of two years, nearly 80% of INR values recorded by the patients themselves were within the target therapeutic range of 2.5-4.5. This corresponds to a high significance of p < = 0.001 in favor of INR self-management. Only 64.9% of INR values monitored by family practitioners were within the desired range. The results differed slightly in quality between patient groups with different levels of training (comprehensive, secondary modern, grammar with or without university). Of patients trained in INR self-management following mechanical heart valve replacement, 91.7% maintained their competence in this technique throughout the entire follow-up period. Only 8.3% of those trained immediately after surgery were unable to continue with INR self-management.

Administration, Oral↗
PubMed2000

Prostaglandin E(1) is able to increase migration of leukocytes through endothelial cell monolayers.

Leukocyte interactions with endothelial cells play an important role during inflammatory processes. Leukocytes pass a monolayer of endothelial cells (ECM) to migrate into the extravascular space. The aim of the current study was to investigate whether prostaglandin E(1) (PGE(1)) influences the process of leukocyte migration. In a prospective controlled study, the influence of prostaglandin E(1) (50-5000 ng/mL) on leukocyte migration through endothelial cell monolayers (n = 7) was investigated. Human umbilical endothelial cells (HUVEC) and/or leukocytes were preincubated with clinically relevant, higher, and lower concentrations of prostaglandin E(1) and the amount of leukocyte migration after 3 h was measured. HUVEC were cultured on microporous membrane filters until achievement of a monolayer for investigation of leukocyte migration. Polymorphonuclear leukocytes (PMNL) were isolated from healthy volunteers and PMNL migration was studied under the influence of PGE(1). In clinically relevant concentrations, PGE(1) was able to increase significantly leukocyte migration through endothelial cell monolayers (205 +/- 7.8%, P < 0.05 compared to control; when treating PMNL alone, migration rate was 120 +/- 9.2% compared to control, ns; only endothelial cell monolayers treated up to 145 +/- 10.2%, P < 0.05 compared to control) showing a dose-dependent effect. In this assay, both cell types (PMNL and ECM) could be treated simultaneously, simulating the clinical situation after an iv administration. In conclusion, PGE(1) is able to increase leukocyte migration through endothelial cell monolayers when both cell types are pretreated. The treatment of either leukocytes or endothelial cell monolayers in the cell coculture showed no significant increase. These findings support the theory that prostaglandins may play a major role during inflammation. Future clinical studies are warranted to confirm this hypothesis.

Adult↗
PubMed2000

Diagnosis and monitoring of acute cytomegalovirus infection in peripheral blood of transplant recipients by nested reverse transcriptase polymerase chain reaction (RT-PCR).

The aim of this novel diagnostic approach is to monitor cytomegalovirus (CMV) infection in immunocompromised transplant recipients using early, sensitive, and specific predictors before and during antiviral therapy. The peripheral blood cells of 20 patients after transplantation (9 liver, 7 kidney, 4 simultaneous kidney-pancreas) were studied for an early diagnosis of acute infection. The mRNA and DNA of human CMV immediate-early antigen (IEA) were detected by nested-polymerase chain reaction (PCR) assay. Results of nested PCR were compared with the immunological detection of antigen pp65 and serological diagnosis of CMV infection. All data were correlated with clinical symptoms like leukopenia, thrombopenia, pneumonia, and allograft-rejection reaction. Of 20 transplant recipients, 12 were infected by CMV, and 9 suffered from a CMV-related disease. CMV mRNA were detected simultaneously with antigen pp65 and CMV DNA in all patients with symptomatic infection. Additionally, CMV mRNA was found over a longer period after ganciclovir treatment of infected recipients. Nested reverse transcriptase (RT)-PCR for CMV-IEA mRNA allows a sensitive and specific diagnosis of an acute CMV infection. CMV mRNA was found to be a good marker of acute viremia and could be a useful tool for CMV monitoring over the whole period of disease management, even during antiviral therapy.

Cytomegalovirus↗
PubMed2000

INR self-management following mechanical heart valve replacement.

INR self-management can reduce severe thromboembolic and hemorrhagic complications following mechanical heart valve replacement. Beginning anticoagulation therapy immediately in the postoperative period further reduces anticoagulant-induced complications. Data were collected from the first 600 surviving patients (from a total study sample of 1200 patients) who completed follow-up of at least 2 years. Patients were randomly divided into a self-management group and a control group. INR self-management reduced severe hemorrhagic and thromboembolic complications (P=0.018). Nearly 80% of INR values recorded by patients themselves, regardless of educational level, were within the target therapeutic range of INR 2.5-4.5, compared with 62% of INR values monitored by family practitioners. Only 8.3% of patients trained in self-management immediately after surgery were unable to continue with INR self-management. The results differed slightly between patient groups with different levels of education. We conclude that all patients for whom anticoagulation is indicated are candidates for INR self-management regardless of education level.

Anticoagulants↗
PubMed2000

Effects of remifentanil on neutrophil adhesion, transmigration, and intercellular adhesion molecule expression.

BACKGROUND: Anaesthetic drugs are used for pain therapy and anaesthesia. Neutrophils play a significant role during the process of inflammation. The aim of the current study was to investigate the effects of remifentanil and fentanyl on neutrophil migration through endothelial cell monolayers, and on adhesion molecule expression. METHODS: After isolation of polymorphonuclear neutrophils (PMNL) we used a currently described migration assay. PMNL and/or endothelial cell monolayers (ECM) were pre-treated with remifentanil using clinically relevant, as well as higher and lower concentrations or relevant concentrations of fentanyl. RESULTS: Concentrations of remifentanil (50 ng/mL) similar to the relevant plasma concentration were able to inhibit PMNL migration through ECM significantly (migration compared to the control 82+/-7% SD; P<0.05), when both cell types were treated with the synthetic narcotic remifentanil. Fentanyl (30 ng/mL) showed a stronger inhibitory effect (migration compared to the control 67+/-9.2%; P<0.05). Endothelial cell adhesion molecule expression was reduced after either remifentanil or fentanyl. CONCLUSION: The results of the present investigation indicate that remifentanil influences interaction of ECM against human neutrophils. Compared to fentanyl, remifentanil seems to exhibit minor inhibitory effects on neutrophil migration.

Analgesics, Opioid↗
PubMed2000

The increased insulin sensitivity in growth hormone-deficient adults is reduced by growth hormone replacement therapy.

BACKGROUND: Growth hormone deficiency is associated with increased morbidity and mortality from cardiovascular diseases, which might be related to changes in glucose and lipid metabolism. DESIGN: To assess the influence of long-term growth hormone replacement therapy (GHRT) on glucose metabolism we examined eight growth hormone-deficient (GHD) adults (seven female/one male; age, 46 +/- 3 years; body mass index, 31 +/- 2 kg m-2) over a period of 18 months in comparison to an adequate control group consisting of eight obese subjects matched for age, sex, and body mass index. We performed frequently sampled intravenous glucose tolerance tests (FSIGT) with minimal model analysis before the study, and after 12 and 18 months. RESULTS: Following GHRT, insulin-like growth factor-1 (IGF-1) increased significantly from a basal level of 75.9 +/- 18.9 to 200.8 +/- 31.0 microg L-1 after 12 months of therapy and remained stable, thereafter. GHRT did not affect fasting blood glucose, basal insulin, cholesterol, blood pressure and body weight. However, at 12 months, HbA1c (6.0 +/- 0.1 vs. 5.6 +/- 0.1% at basal, P < 0.05) and triglyceride (2.3 +/- 0.4 vs. 1.4 +/- 0.3 mmol L-1) significantly increased but returned to pretreatment values at 18 months. Insulin sensitivity was higher in GHD (8.2 +/- 3.1) compared to controls (3. 6 +/- 0.53 x 10-4 min-1/(microU mL-1), P = 0.06) and decreased significantly after 18 months of GHRT to 5.1 +/- 2.6, P < 0.05. Basal insulin secretion was similar to that in the control group and increased significantly after 12 and 18 months, total insulin secretion only after 12 months. SG (glucose effectiveness)was lower in GHD patients (0.0095 +/- 0.001 min-1) compared to controls (0.020 +/- 0.003 min-1, P < 0.05) and increased significantly after 12 and 18 months of GHRT (0.016 +/- 0.002, and 0.015 +/- 0.001 min-1, P < 0. 05), respectively. Hepatic insulin extraction rate was similar in both groups and remained unchanged following GHRT. CONCLUSION: We conclude that long-term GHRT induces a significant decrease of the increased insulin sensitivity in GHD patients to levels observed in body mass index-matched control subjects. This is accompanied by an increase in basal and total insulin secretion as well as in glucose effectiveness as a possible compensatory mechanism.

Adult↗
PubMed1999

Rapid, fluorescence-based assay for microtiter plates to test drug influences on neutrophil transmigration through endothelial cell monolayers.

Investigation of drug interactions between blood cells and endothelium is of high interest. The current study describes the development of a rapid fluorescence-based leukocyte transmigration system through endothelial cell monolayers for investigation of drug influences. To test the new assay, endothelial cells were cultured on microporous filters, pore size 3.0 microm, in 96-well-plates. Freshly isolated neutrophils were seeded on endothelial cell monolayers and transmigrated cells were measured after incubation for three hours. Migration of non-stimulated neutrophils through non-stimulated endothelial cell monolayer was used as control and set as 100%. The influence of the non-steroidal anti-inflammatory drug diclofenac was investigated. Assay precision tests were done using intraassay (within-day variability) and interassay (day-to-day variability) controls. Transmigration rate was decreased to 53 +/- 6.8% SD (diclofenac 0.7 microg/mL). Different concentrations showed a dose dependent effect (0.07 microg/mL: 97 +/- 9.5%, 7 microg/mL: 37 +/- 4.7%). Analysis of assay accuracy of the new 96-well-sized transmigration assay showed reliable results (coefficient of variation: intraassay 8.2 %; interassay 11.8%). In conclusion, this new, rapid, and sample saving 96-well-microtiter transmigration assay allows examination of drug influence on neutrophil migration through endothelial cell monolayers. Moreover, this assay can also be used for other cell-cell interactions.

Adult↗
PubMed1999

Absolute levels of MDR-1, MRP, and BCL-2 MRNA and tumor remission in acute leukemia.

Mononuclear cells prepared from peripheral blood or bone marrow of 119 AML and 28 ALL patients prior and following therapy were analyzed for absolute transcript levels of the chemoresistance genes mdr-1 and MRP, and the proto-oncogene bcl-2, by validated contamination-protected quantitative RT-PCR. In newly diagnosed AML mainly tumors of the granulocytic lineage (FAB M1-M2) expressed increased mdr-1 mRNA amounts. The MRP gene was expressed in all investigated samples without relation to a particular FAB class. High initial expression of both genes did not confer a poor prognosis even at high number of CD34+ cells. Data compared prior to and after therapy start (paired samples) revealed that AML patients who did not respond to therapy (NR) expressed increased levels of mdr-1 mRNA, as well as MRP and bcl-2 cDNA normalized to GAPDH reference transcripts, when compared to patients achieving complete remission (CR; p = 0.003, 0.008 and 0.0005, respectively). In ALL-NR the mdr-1 and bcl-2 genes were entirely more active after induction chemotherapy. Arbitrary cut-off values were established in order to delimit pathological from non-pathological gene expression. 59% of studied AML and 33% of ALL-NR exceeded the arbitrary values (mdr-1: > 2 amol/microgram RNA, MRP: > 10 zmol/amol GAPDH, bcl-2: > 5 zmol/amol GAPDH) for one and 11% of AML-NR for two parameters. Only 17% of the AML-CR and none of the ALL-CR group were above these limits. The results indicate that high individual activity of usually one, rarely two of the investigated genes might be associated with poor clinical outcome in treated acute leukemia.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Influence of prothrombin complex concentrates on plasma coagulation in critically ill patients.

OBJECTIVE: To evaluate thrombogenicity of prothrombin complex concentrates (PCCs) in critically ill patients. DESIGN: Prospective clinical study. SETTING: Medical intensive care unit at a university hospital. PATIENTS: 16 consecutive patients suffering from acquired deficiencies of coagulation factors and with either overt bleeding from any site or a planned invasive procedure. INTERVENTIONS: 2000 factor IX units of PCCs intravenously. MEASUREMENTS AND RESULTS: Prothrombin time (PT), activated partial prothrombin time, fibrinogen, platelet count, plasma levels of coagulation factors II, V, VII, VIII, IX, X, antithrombin, protein C, thrombin-antithrombin complex (TAT), prothrombin fragment F(1+2), and the fibrin degradation product D-dimer were measured prior to and 1, 3, and 24 h after administration of PCCs. PT as well as coagulation factors II, VII, IX, and X, TAT, and F(1+2) showed a significant increase after administration of PCCs. All other parameters remained unchanged. CONCLUSIONS: Administration of PCCs induces thrombin generation. No evidence for induction of disseminated intravascular coagulation in biochemical terms could be found. When rapid correction of acquired coagulation factor disturbances is warranted, the use of PCCs seems reasonable, but the elevated risk of intravascular thrombus formation should be kept in mind.

Adult↗
PubMed1999

Viscoelastic properties of f-actin, microtubules, f-actin/alpha-actinin, and f-actin/hexokinase determined in microliter volumes with a novel nondestructive method.

A nondestructive method to determine viscoelastic properties of gels and fluids involves an oscillating glass fiber serving as a sensor for the viscosity of the surrounding fluid. Extremely small displacements (typically 1-100 nm) are caused by the glass rod oscillating at its resonance frequency. These displacements are analyzed using a phase-sensitive acoustic microscope. Alterations of the elastic modulus of a fluid or gel change the propagation speed of a longitudinal acoustic wave. The system allows to study quantities as small as 10 microliters with temporal resolution >1 Hz. For 2-100 microM f-actin gels a final viscosity of 1.3-9.4 mPa s and a final elastic modulus of 2.229-2.254 GPa (corresponding to 1493-1501 m/s sound velocity) have been determined. For 10- to 100-microM microtubule gels (native, without stabilization by taxol), a final viscosity of 1.5-124 mPa s and a final elastic modulus of 2.288-2. 547 GPa (approximately 1513-1596 m/s) have been determined. During polymerization the sound velocity in low-concentration actin solutions increased up to +1.3 m/s (approximately 1.69 kPa) and decreased up to -7 m/s (approximately 49 kPa) at high actin concentrations. On polymerization of tubulin a concentration-dependent decrease of sound velocity was observed, too (+48 to -12 m/s approximately 2.3-0.1 MPa, for 10- to 100-microM tubulin). This decrease was interpreted by a nematic phase transition of the actin filaments and microtubules with increasing concentration. 2 mM ATP (when compared to 0.2 mM ATP) increased polymerization rate, final viscosity and elastic modulus of f-actin (17 microM). The actin-binding glycolytic enzyme hexokinase also accelerated the polymerization rate and final viscosity but elastic modulus (2.26 GPa) was less than for f-actin polymerized in presence of 0.2 mM ATP (2.28 GPa).

Acoustics↗
PubMed1999

Oral contraceptives that contain ethinyl estradiol (0.035 mg) and cyproterone acetate (2 mg) inhibit leukocyte transmigration through endothelial cell monolayers.

OBJECTIVE: To investigate the influence of ethinyl estradiol and cyproterone acetate in oral contraceptives on leukocyte migration through endothelial cell monolayers. DESIGN: Experimental in vitro prospective study. SETTING: An academic research laboratory. INTERVENTION(S): Endothelial cells were cultured on microporous membranes to produce monolayers. Polymorphonuclear leukocytes were used in a previously described migration assay (n = 7). The amount of untreated polymorphonuclear leukocytes that migrated through untreated endothelial cell monolayers was used as a control and set at 100%. In addition, a leukocyte adhesion assay was used. MAIN OUTCOME MEASURE(S): Leukocyte adhesion to and transmigration through endothelial cell monolayers. RESULT(S): Ethinyl estradiol and cyproterone acetate inhibited the migration of polymorphonuclear leukocytes through endothelial cell monolayers significantly (67% +/- 6.4%) when both cell types were treated to simulate in vivo conditions. The adhesion assay produced similar results. CONCLUSION(S): Ethinyl estradiol and cyproterone acetate were identified as potent inhibitors of leukocyte migration through endothelial cell monolayers.

Cell Adhesion↗