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G Hafner

Publications and source records attributed to G Hafner.

At least 91 records · Page 5Linked to original sources
PubMed1992

Results of the multicenter evaluation of a novel homogeneous immunoassay for digoxin based on the cloned enzyme donor immunoassay technology.

A new CEDIA assay for the measurement of digoxin in serum on random access analyzers was evaluated by twelve laboratories in Europe and the United States. Studies on the analytical range, reproducibility, calibration stability, recovery in controls, interlaboratory comparability, comparability with routine methods, and the effect of various interfering factors have been performed and the results are presented in this paper. The analytical performance was comparable to that of routine methods provided the manual pipetting step for pre-incubation was performed with accurate pipettes. A major advantage of the CEDIA Digoxin assay in terms of convenience is the simple two-point calibration procedure. Moreover, digoxin can be determined within 15 minutes after receiving the samples on random access analyzers like Boehringer Mannheim/Hitachi analysis systems. Thus, the CEDIA Digoxin assay represents an attractive alternative to the measurement of digoxin on dedicated immunochemical assay systems.

Calibration↗
PubMed1992

Results of the multicenter evaluation of a homogeneous immunoassay for digitoxin based on the cloned enzyme donor immunoassay technology.

We evaluated a CEDIA assay for the determination of digitoxin in serum on random access analyzers. The multicenter evaluation included studies on the analytical range, calibration stability and reproducibility of the new assay. Moreover, recovery in controls, transferability of results obtained in different laboratories, comparability with routine methods, and the effect of various interfering factors have been analyzed. Summarized the analytical performance was comparable to that of routine methods. The CEDIA Digitoxin assay represents an attractive alternative to established digitoxin immunoassays because it can be performed on random access analyzers, thus permitting the simultaneous determination of digitoxin and other serum analytes without sample splitting.

Digitoxin↗
PubMed1991

Acute dialysis: PMN-elastase as a new parameter for controlling individual anticoagulation with low molecular weight heparin (Fragmin).

Despite the improvements in the development of dialyzer membranes with greater hemocompatibility, an activation of the coagulation system occurs when blood comes into contact with exogenous surfaces. The large number of heparin dosage regimens demonstrated the difficulty to adapt general therapeutic guidelines. Low molecular weight heparin (Fragmin) was administered as a single bolus dose for anticoagulation during 58 acute dialyses. Anti-Xa-activity, the plasma levels of the lysosomal elastase of the polymorphonuclear granulocytes ("PMN-elastase") and of the thrombin-antithrombin III-complex (TAT) were measured at hourly intervals. Therapeutic anti-Xa-levels did not show evidence of sufficient inhibition of thrombin formation. The PMN-elastase increased by 180 ng/ml 3 h after administration of the bolus dose, with no further increase occurring (plateau phase). This was considered to reflect adequate anticoagulative activity. Where anticoagulation was inadequate, the elastase values rose consistently. After 2 h the increase of the PMN-elastase showed that--and to what extent--coagulation had been activated. The determination of PMN-elastase, using the IMAC-principle, is a method which can be performed quickly with any conventional autoanalyzer. It makes it possible to monitor adequate anticoagulation, but PMN-elastase results must be proven during routine use before recommendation as a routine test.

Acute Kidney Injury↗
PubMed1991

Determination of human granulocyte elastase by the immunoactivation method on the Hitachi 717 automated analyser.

This paper describes a fully mechanized homogeneous immunoassay using the immunoactivation method for the rapid and specific determination of human granulocyte elastase (EC 3.4.21.37) in plasma. The method uses anti-elastase antibody fragments from sheep, conjugated to horseradish peroxidase. These enzyme-antibody conjugates bind to the elastase-alpha 1-proteinase inhibitor complex present in plasma. A separate sample blank with non-specific sheep antibody fragments conjugated to horseradish peroxidase corrects for errors introduced by the sample matrix. Measurements were performed with the clinical chemistry analyser Hitachi 717. A single determination can be performed in 10 min, requiring 24 microliters sample volume. The measuring range is about 20 to 1000 micrograms/l elastase. For within-run precision the coefficients of variation are 4.77%, 4.48% and 1.85% for elastase concentrations of 45.7, 89.1 and 385.4 micrograms/l; for day-to-day precision the coefficients of variation are 15.81%, 7.19% and 4.12% for elastase concentrations of 31.1, 65.5 and 440.2 micrograms/l, respectively. Correlation (y = bx + a) of results with those from the heterogeneous immunoassay showed a good agreement (r = 0.93, b = 1.11, a = -27.0, N = 121). Interferences by endogeneous substances and by drugs at therapeutic doses were not observed. The reference interval, determined by using plasma from 215 healthy individuals (C-reactive protein less than 5 mg/l, leukocyte count 4-8 x 10(9)/l), was 9-56 micrograms/l (2.5th to 97.5th percentile), with a median of 27 micrograms/l.

Autoanalysis↗
PubMed1991

[Effect of molsidomine on fibrinolytic activity: a double-blind, randomized study].

The influence of molsidomine on endogenous fibrinolytic activity was studied in a double-blind, randomized, placebo-controlled trial involving 12 male healthy volunteers. When measured 3 h after oral intake of molsidomine (16 mg, slow-release formulation) the activity of tissue plasminogen activator (t-PA) in plasma was significantly increased from 1.1 +/- 0.1 to 1.6 +/- 0.1 IU/ml. In contrast, the activity of plasminogen activator inhibitor (PAI-I) decreased from 17 +/- 2 to 12 +/- 1 AU/ml. The ratio of t-PA/PAI-I (x 100), calculated as index for the endogenous fibrinolytic activity increased significantly from 8.1 +/- 1.1 to 14.5 +/- 1.6. The ratio was unaltered after intake of placebo. Additionally, collagen-induced platelet aggregation was significantly inhibited following intake of molsidomine. The results demonstrate a significant increase in endogenous fibrinolytic activity after oral intake of molsidomine. These effects may be of therapeutic value in patients with coronary heart disease and unstable angina.

Administration, Oral↗
PubMed1991

[Modification of thrombocyte function in diagnostic and therapeutic interventions in cardiology].

In patients with coronary heart disease platelet activity may be pathologically increased. Administration of platelet inhibitor drugs is an established treatment principle. The interactions between platelet activation, platelet inhibitor drugs like acetylsalicylic acid (ASA) or molsidomine and the endogenous fibrinolysis were studied in three trials. Platelet aggregation and thromboxane synthesis are dose- dependently inhibited after oral intake of ASA (0, 10, 30, 100 or 500 mg/d) Additional intake of the antianginal agent and nitric oxide donator Molsidomine (8 mg) results in a synergistic platelet inhibitor effect characterized by a significantly delayed aggregation response. In a group of patients with coronary artery stenoses platelet activity was markedly enhanced, when compared to healthy individuals. During physical exercise platelet activity was even further enhanced and plasma t-PA-activity was increased by a factor of 2.2. The stimulation of the endogenous fibrinolytic system was markedly reduced when compared to healthy subjects. Following successful coronary angioplasty 393 patients were randomized to receive either molsidomine (2 x 8 mg/d) or ASA (1 x 500 mg/d) plus nifedipine (3 x 20 mg/d). Coronary angiography performed after the 6 month treatment period revealed a restenosis rate of 29% in the molsidomine group and of 33% in patients treated with ASA + nifedipine. This difference was not statistically significant.

Angioplasty, Balloon, Coronary↗
PubMed1990

[Value of the elastase-alpha 1-proteinase inhibitor complex in pediatric oncologic patients with fever].

The elastase-alpha1-proteinase inhibitor complex (E-alpha 1-PI) is a well known, sensitive indicator of infection. The significance of this parameter was investigated in 12 febrile paediatric-oncological patients. With neutrophil counts greater than 500/microliters infections caused a definitive increase in E-alpha 1-PI serving as an additional diagnostic parameter. E-alpha 1-PI provided no additional information in situations of sepsis with leukopenia and simultaneous agranulocytosis. In patients with metastatic tumours, the assay of E-alpha 1-PI may differentiate between infection-related and tumour-related serological disturbances.

Child↗
PubMed1989

Immunonephelometric determination of the apolipoprotein A-II.

A fully mechanized immunonephelometric method is described for the rapid and specific determination of apolipoprotein A-II in serum. The method utilizes commercially available sheep antiserum against human apolipoprotein A-II. Nephelometry was performed with the Behring Nephelometer Analyzer (BNA). A single determination can be performed in 12 minutes, requiring 10 microliters sample volume. The measuring range is about 0.08 to 1.25 g/l apolipoprotein A-II. Precision is characterized by intra-assay coefficients of variation of 3.37%, 3.93% and 4.49% for apolipoprotein A-II concentrations of 1.22 g/l, 0.376 g/l and 0.185 g/l, and inter-assay coefficients of variation of 4.27% for an apolipoprotein A-II concentration of 0.404 g/l, respectively. Accuracy of the method is shown by the close correlation of results with those from radial immunodiffusion (r = 0.913, y = 1.091 x -0.033, n = 75).

Apolipoprotein A-II↗
PubMed1986

Rapid determination of vitamin A (retinol) and vitamin E (alpha-tocopherol) in human serum by isocratic adsorption HPLC.

The simultaneous determination of alpha-tocopherol and retinol in human serum is reported. The separation is carried out by means of isocratic HPLC on adsorption columns. UV-Detection is possible by using either one wavelength for both compounds (300 nm), or after a lambda change mode with typical wavelengths for alpha-tocopherol (292 nm) and retinol (325 nm). According to short retention times (10 min) and rapid extraction the method is useful for clinical research and allows about 50 analyses per day and operator. Blood from 176 human volunteers was collected and alpha-tocopherol and retinol levels in serum determined with this method. Statistical evaluation of different selected groups shows typical significant differences of alpha-tocopherol and retinol concentrations in smokers and oral contraceptive users.

Adsorption↗
PubMed1985

[Vitamin A in the serum of healthy probands and clinical groups].

The estimation of vitamin A in serum of patients suffering from different diseases (M. Crohn, Hypothyroidism, Hyperthyroidism, Liver cirrhosis, Renal insufficiency, Carcinoma of Prostate, ENT-Carcinomas) and healthy controls by means of a recent developed method (HPLC) is reported. Decreased and increased vitamin A serum levels had been reported in literature during different diseases but we could not reveal identical results in all cases. Significantly lowered values were only estimated in patients suffering from liver cirrhosis whereas increased vitamin A serum levels were determined during renal insufficiency. In hypo- or hyperthyroidism there was no difference from healthy persons. In patients with Crohn's disease the distribution of vitamin A concentrations in serum was bimodal, probably depending on extension and localization of the process. Patients with carcinoma of the prostate had only minor deviations from the normal value, whereas patients with tumors of the larynx had in part very low vitamin A concentrations with a bimodal distribution. Causes for the deviations and consequences for the assessment of the vitamin A status of patients under intravenous alimentation are discussed.

Contraceptives, Oral, Hormonal↗
PubMed1983

Rapid determination of retinol (vitamin A) in serum by high pressure liquid chromatography (HPLC).

A simple, fast, and specific HPLC-method to estimate retinol (vitamin A) in serum is reported. In the presence of small amounts of acetonitrile retinol is extracted quantitatively with n-hexane from serum. Neither the use of an internal standard nor evaporation to concentrate the extract is necessary. The HPLC-method avoids interferences of substances like phytofluenes, carotinoids or retinyl palmitate which is present in serum to a fraction of about 2-5%. The HPLC-method was applied to healthy adults and healthy children. The method allows about 100 determinations per day and operator.

Adolescent↗
PubMed1977

Comparative study of social and psychological analyses in asthmatic, rheumatic and diabetic children.

The authors have analysed clinically, biochemically, immunologically, psychologically and socially three groups of children with chronic diseases using special perforated cards with 49 data for each illness. All data have registered in special passport for each child. 278 children with bronchial asthma were medically, socially and psychologically compared to 27 rheumatic and 19 diabetic children. All statistical calculations showed significantly higher disturbances in asthmatic and diabetic children than in rheumatics.

Asthma↗
PubMedDate not supplied

In vitro flow properties of glaucoma implant devices.

PURPOSE: To develop a protocol for testing glaucoma implant devices and to use this protocol to characterize devices currently available. METHODS: The following devices were obtained: Ahmed Glaucoma Valve Implant, Baerveldt Implant, Krupin Eye Valve, Joseph Valve, and OptiMed Glaucoma Pressure Regulator. Pressure per unit time was measured in real-time during ramped pressure perfusion of the implant devices with an open-manometer system. Each device was measured during a 10 minute interval while a constant flow of fluid was pumped into the system. The open manometer allowed the resistance of the devices to generate a pressure head which was monitored by computer. Four independent runs were averaged for each device. RESULTS: The Ahmed devices demonstrated reliable valve performance with a mean opening pressure of 13.65 mm Hg, a facility flow of 1.2 microL/min/mm Hg and a closing pressure of 6.1 mm Hg. The Baerveldt devices had a mean facility flow of 7.56 microL/min/mm Hg. The Joseph devices had the most variable performance, opening from 2.05 to 6.21 mm Hg. Two of 4 Joseph devices had high facility of flow (5 microL/min/mm Hg). The Krupin devices had a mean opening pressure of 6.25 mm Hg in 3 of 4 devices. The remaining Krupin device did not exhibit valve behavior. The OptiMed device did not reveal an opening pressure, and had a mean facility of flow of 7.08 microL/min/mm Hg for high flow and 6.20 microL/min/mm Hg for low flow. CONCLUSION: An objective test protocol for glaucoma implant devices was demonstrated. All implant devices had high facility of flow compared to the normal eye and can be grouped into very high facility (Baerveldt and OptiMed), and high facility (Ahmed, Joseph and Krupin). Only the Ahmed device had consistent valve behavior. None of the devices created enough resistance to explain long-term clinical failure of glaucoma drainage device surgery.

Aqueous Humor↗
PubMedDate not supplied

Routine extracorporeal circulation with a centrifugal or roller pump.

In a randomized, prospective clinical trial, 50 patients undergoing elective coronary artery bypass grafting (CABG) were divided into two groups of 25 each. Group I had a centrifugal pump (CP, Biomedicus) and Group II a roller pump (RP, Stöckert) as the arterial line. Neither group differed significantly, and variables during surgery were kept to a minimum. The parameters studied included the cellular blood elements and their components, such as PMN-elastase (PMN-E), plasma hemoglobin (pHb), beta-thromboglobulin (beta-TG), and D-dimer (D-D) and thrombin-antithrombin III complex (TAT) as indicators for activated coagulation. Blood and urine samples were taken at induction of anesthesia, every 15 minutes throughout extracorporeal circulation (ECC), at arrival in the ICU, and 1, 3, 6, 12, and 24 hours thereafter. No difference between the groups was found in bypass time, ECC flow or volume, or fluid balance. Significant differences in favor of Group I were found in pHb (p less than 0.05), beta-TG (p less than 0.01), D-D (p less than 0.05), and platelet counts (p less than 0.05). These differences were clearly ECC time dependent, became significant after 90 minutes of bypass, but disappeared within hours after surgery. No difference in patient outcome, ICU time, or need for volume substitution was seen. It is concluded that the RP can be safely used for routine ECC, but should be supplied with a CP in complex and prolonged cardiosurgical procedures to avoid severe postperfusion syndrome.

Coronary Artery Bypass↗