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H Reinauer

Publications and source records attributed to H Reinauer.

At least 37 records · Page 2Linked to original sources
PubMed1996

Comparison of biochemical markers of bone resorption in patients with metabolic and malignant bone diseases.

The clinical usefulness of the urinary excretion of three bone resorption markers is compared in patients after renal transplantation and in tumour patients with and without bone metastases. The markers were the 3-hydroxypyridinium derivatives pyridinoline and deoxypyridinoline (pyridinium cross-links; measured by a polyclonal enzyme immunoassay), the cross-linked N-telopeptid-to-helix domain of type I collagen and the destruction products of type I collagen metabolism cross-reacting with a peptide sequence of the alpha 1-chain of the C-terminal telopeptide region of type I collagen (CrossLapsTM). In patients receiving renal transplantation the discriminating power of N-telopeptides was superior to that of pyridinium cross-links and CrossLapsTM, with Z scores (number of SDs from apparently healthy controls) of 6.61, 2.17 and 1.35, respectively. However, the pyridinium cross-links were the only markers for bone resorption which showed a significant increase with time (P < 0.001). Receiver operating-characteristic analysis for discriminating patients with bone metastases from those without revealed that the accuracy was 0.81 for pyridinium cross-links, 0.76 for the N-telopeptides and 0.61 for CrossLapsTM. The discriminating power for patients with bone metastases was higher for pyridinium cross-links and N-telopeptides than for CrossLapsTM, with Z scores (number of SDs from patients without bone metastases) of 4.38, 3.00 and 1.24, respectively. Linear correlation coefficients for the different markers were between +0.35 and +0.65 in patients receiving renal transplants, and between +0.58 and +0.84 in patients with bone metastases. In conclusion, in patients with metabolic and malignant bone diseases there are marked differences in the diagnostic performance of different biochemical markers of bone resorption. It is suggested that this may reflect the different facets of bone resorption or the different metabolic fates of the marker substances examined.

Biomarkers↗
PubMed1996

Monitoring of bone metabolism after bone marrow transplantation by measuring two different markers of bone turnover.

Bone marrow transplant recipients may be at increased risk of osteoporosis. In a cross-sectional study we therefore measured two biochemical markers of bone turnover, bone alkaline phosphatase and the C-terminal propeptide of type I procollagen, in 22 serum samples from 9 patients before allogeneic bone marrow transplantation and 85 serum samples from 14 patients after allogeneic bone marrow transplantation. Following allogeneic bone marrow transplantation, female (but not male) patients showed elevated serum bone alkaline phosphatase values (p < 0.05). After bone marrow transplantation both female and male patients were characterized by elevated serum concentrations of the C-terminal propeptide (p < 0.01). Both the duration of cyclosporin A therapy (p < 0.05) and the time since transplantation (p < 0.01) were independent predictors of serum bone alkaline phosphatase values, whereas the duration of cyclosporin A therapy was the only independent predictor of C-terminal propeptide serum concentrations (p < 0.01). There was a correlation between bone alkaline phosphatase serum concentrations and C-terminal propeptide values in serum (p < 0.0001). These findings indicate an accelerated bone turnover in patients following bone marrow transplantation due to the stimulation of osteoblasts by cyclosporin A. In addition, oestrogen deficiency after total body irradiation may accelerate bone mass loss in female patients.

Adult↗
PubMed1996

Relationship between bone metabolism and plasma cytokine levels in patients at risk of post-transplantation bone disease after bone marrow transplantation.

Bone marrow transplant recipients may carry an increased risk of bone diseases, involving numerous factors that affect bone mineral metabolism. Interleukin-6 is a potent stimulator of bone resorption in vivo. The soluble fraction of interleukin-6 receptor is reported to trigger osteoclast formation by interleukin-6 in vitro. In a cross-sectional study we measured serum bone alkaline phosphatase concentrations and the urinary excretion of pyridinium cross-links in 21 patients after bone marrow transplantation, and investigated the relationship between these values and those for the plasma levels of interleukin-6 and soluble interleukin-6 receptor. Following bone marrow transplantation female--but not male--patients showed higher serum bone alkaline phosphatase values than age- and sex-adjusted controls (p < 0.05). Both female and male patients were characterized by increased urinary excretion values of pyridinium cross-links (p < 0.05). In contrast to a marked increase of interleukin-6 plasma levels (p < 0.001) no significant difference in the soluble interleukin-6 receptor levels was found between patients and apparently healthy persons (p = 0.838). Multiple regression analysis (taking into account different variables of the immunosuppressive regimen applied) revealed the plasma concentration of interleukin-6 as an independent predictor of the urinary excretion of pyridinium cross-links (p < 0.05). In conclusion, in patients following bone marrow transplantation, these findings indicate (a) an increase of bone formation in female--but not in male--patients possibly reflecting primary ovarian failure and (b) an enhancement of bone resorption possibly mediated by circulating interleukin-6.

Adult↗
PubMed1996

Automation in coagulation testing.

Belatedly, automation is being introduced into hemostasis laboratories. Now, new analytic systems are also available for less specialized laboratories. New tests have been added as knowledge of the mechanisms of coagulation increases. This article will review the new technologies in coagulation testing and their diagnostic applications.

Blood Coagulation Tests↗
PubMed1996

Method for determination of bone alkaline phosphatase activity: analytical performance and clinical usefulness in patients with metabolic and malignant bone diseases.

We report the performance characteristics of an assay for determination of bone alkaline phosphatase (ALP) activity after immunoadsorption in microplate wells. Between-run imprecision was between 7.1% and 11.2%. The detection limit was 1.0 U/L. Comparisons with an immunoradiometric test for determination of bone ALP mass concentrations yielded the following regression equation: y = 3.11 + 1.33x with y, the bone ALP activity concentration (U/L) (and x, the bone ALP mass concentration microgram/L) (r +=0.974, n = 103). Using sera from patients with liver diseases and sera from patients with secondary hyperparathyroidism yielded a cross-reactivity of 20% for circulating liver ALP (and its membrane-bound isoform). In patients receiving renal transplants, Z-score analysis revealed that after transplantation the increase in bone ALP activity is more pronounced than total ALP activity. In tumor patients, receiver-operating characteristic analysis revealed that bone ALP activity shows the same diagnostic efficacy as total ALP activity in the detection of bone metastases (as assessed by bone scintigraphy). In multiple myeloma patients, suppressed osteoblast activity was well detectable by bone ALP activity determination.

Adult↗
PubMed1996

Determination of reference method values by isotope dilution-gas chromatography/mass spectrometry: a five years' experience of two European Reference Laboratories.

We report on the cooperation of two European Reference Laboratories for the determination of reference method values in serum based materials intended for use in internal accuracy control and external quality assessment. Reference method values were determined by isotope dilution-gas chromatography/mass spectrometry for aldosterone, cortisol, oestradiol-17 beta, progesterone, testosterone, thyroxine, theophylline, cholesterol, creatinine, glucose, total triacylglycerols and uric acid. All determinations were done in parallel in the two laboratories, independently and within certain time constraints. The general measurement design consisted of duplicate measurement of each sample on three different occasions. In each laboratory, rigorous internal quality control was performed according to predefined analytical quality specifications. This was done using certified reference materials. If not available, control materials targeted before by the two laboratories were utilized. Here we present the results of the cooperation during five years. We discuss the precision and accuracy achieved, the between-laboratory agreement and the total analytical error. For the hormones and theophylline, the mean overall coefficient of variation for both laboratories (calculated from the measurements on three days) was always < 2%, for the substrates < 1%. For all substances, the method bias (estimated from several measurement series over the five years) was < 1%, and the average deviation of the results between the two laboratories was < 1.2%. The maximum total analytical error was in all cases < 3%. These data demonstrate that current reference methodology is able to guarantee a stable level of high quality of performance, and that reference laboratories of today are capable of providing, in due time, adequate service in the framework of accuracy-based harmonization of methods in routine laboratory medicine.

Aldosterone↗
PubMed1996

[Endothelin and big endothelin in coronary heart disease and acute coronary syndromes].

Endothelin (ET), the most potent endogenous vasoconstrictor with mitogenic potency, is generated from its precursor big-endothelin (BET) in a proteolytic process and discussed as a pathogenetic factor in coronary artery disease and in the acute coronary syndromes. Several studies documented elevated plasma endothelin concentrations in acute myocardial infarction, but conflicting results were reported in patients with stable and unstable angina. Only few studies determined big endothelin, although it half-life and plasma concentrations are higher in comparison to endothelin. ET and BET levels (Radioimmunoassay, Biomedica GmbH, Vienna) were determined in patients with stable angina (SAP, n = 20), unstable angina (IAP, n = 12), acute myocardial infarction (AMI, n = 12) and healthy subjects (NP, n = 11). The concentrations of ET and BET (median (minimum-maximum) in fmol/ml) of the patients with stable angina (SAP: ET 0.7 (0.3-1.1); BET 1.7 (0.7-2.9)), unstable angina (IAP: ET 1.0(0.5-1.7); BET 2.5 (1.3-4.1)) and acute myocardial infarction (AMI: ET 1.2 (0.6-2.3); BET 3.6 (3.2-5.3)) showed a significant difference compared to controls (NP: ET 0.5 (0.4-0.7); BET 1.4 (1.1-1.7)) (SAP vs. NP: ET p < 0.01; BET p < 0.05; IAP and AMI vs. NP: ET and BET p < 0.001). Also, the concentrations of the peptides differed significantly dependent on the clinical severity of coronary artery disease (AMI vs. SAP: ET and BET p < 0.001; AMI vs. IAP: BET p < 0.05; IAP vs. SAP: ET p < 0.05; BET p < 0.01). Twelve of 15 patients with big endothelin concentrations over 3 fmol/ml suffered acute myocardial infarction. Seven of 12 patients with AMI showed elevated ET and BET concentrations before the increase of creatinecinase. There was no correlation between number of risk factors per patient, cholesterin and subfractions, severity of CAD classified in one-two-three-vessel disease or coronary score according to modified criteria of the American Heart Association (AHA). We conclude that in patients with coronary artery disease endothelin and big endothelin levels are elevated and related to the clinical and not to the morphological severity of coronary artery disease. Big endothelin is the more sensitive parameter in comparison to endothelin and indicates a severe course of myocardial ischemia in patients with unstable angina. The development of assays with the possibility of a quick determination of the peptides may be valuable for risk stratification of acute coronary events.

Adult↗
PubMed1995

Comparison between serum levels of bone alkaline phosphatase and the carboxy-terminal propeptide of type I procollagen as markers of bone formation in patients following renal transplantation.

The serum concentrations of the carboxy-terminal propeptide of type I procollagen (PICP) were monitored in 52 serum samples from 13 patients receiving renal transplants and the values compared with bone alkaline phosphatase (BAP) concentrations and intact parathyrin levels. There was a significant correlation between BAP and PICP values in all 52 serum samples examined (r = +0.770; P < 0.0001). Before transplantation BAP (P < 0.0001), but not PICP (P > 0.1), was correlated with intact parathyrin levels. BAP concentrations increased from 7.3 +/- 1.2 micrograms/l (median +/- S.E.M.) before transplantation to 13.3 +/- 1.2 micrograms/l 3 months after transplantation (P < 0.01). There was a concomitant rise in PICP levels from 95 +/- 19 micrograms/l to 166 +/- 27 micrograms/l (P < 0.05). No correlation was found between BAP or PICP levels on the one hand and intact parathyrin concentrations on the other at any time following renal transplantation (P > 0.5). In conclusion, PICP may be a useful parameter for monitoring bone formation following renal transplantation.

Adult↗
PubMed1995

Studies on the activation by ATP of the 26 S proteasome complex from rat skeletal muscle.

The 26 S proteasome complex is thought to catalyse the breakdown of ubiquitinated proteins within eukaryotic cells. In addition it has been found that the complex also degrades short-lived proteins such as ornithine decarboxylase in a ubiquitin-independent manner. Both proteolytic processes are paralleled by the hydrolysis of ATP. Here we show that ATP also affects the hydrolytic activity towards fluorigenic peptide substrates by the 26 S proteasome complex from rat skeletal muscle tissue. Low concentrations of ATP (about 25 microM) optimally activate the so-called chymotryptic and tryptic activity by increasing the rate of peptide hydrolysis but not peptidylglutamylpeptide hydrolysis. Activation of the enzyme by ATP is transient but this effect can be enhanced and prolonged by including in the assay an ATP-regenerating system, indicating that ATP is hydrolysed by the 26 S proteasome complex. Although ATP cannot be substituted for by adenosine 5'-[beta,gamma-methylene]triphosphate or AMP, hydrolysis of the phosphoanhydride bond of ATP seems not to be necessary for the activation process of the proteasome complex, a conclusion drawn from the findings that ATP analogues such as adenosine 5'-[beta,gamma-imido]triphosphate, adenosine 5'-O-[gamma-thio]triphosphate, adenosine 5'-O-[beta-thio]-diphosphate and adenosine 5'-[alpha,beta-methylene]triphosphate give the same effect as ATP, and vanadate does not prevent ATP activation. These effects are independent of the presence of Mg2+. Thus, ATP and other nucleotides may act as allosteric activators of peptide-hydrolysing activities of the 26 S proteasome complex as has also been found with the lon protease from Escherichia coli.

Adenosine Triphosphate↗
PubMed1995

Efficacy of simultaneous determination of bone alkaline phosphatase mass concentration in serum and urinary excretion of pyridinium cross-links for detection of bone metastases.

OBJECTIVES: To examine the diagnostic validity of bone alkaline phosphatase (BAP) in serum (a marker of bone formation) and of urinary excretion of pyridinium cross-links (PYR) (a marker of bone resorption) for detection of bone metastases. DESIGN AND METHODS: Two heterogeneous immunoassays were employed for determination of BAP mass concentrations (Tandem-R Ostase) in serum and the urinary excretion of PYR (Collagen Crosslinks) in a consecutive series of 89 tumor patients examined by bone scintigraphy (with 99mTc-methylene diphosphonate). RESULTS: The discrimination power (as determined by Z score analysis) and the accuracy (as assessed by the area under the receiver-operating characteristic curve) was higher for BAP (0.84) than for PYR (0.76). Combination of both markers yielded a further increase of accuracy (0.89). There was a correlation (r = +0.422; p < 0.001) between the urinary excretion of pyridinium cross-links and bone alkaline phosphatase mass concentrations in the whole of 89 patients examined. In 14 (16%) of 89 patients bone alkaline phosphatase values were within the reference interval in spite of total alkaline phosphatase activity being increased; this indicates a higher diagnostic specificity of bone alkaline phosphatase (compared with total alkaline phosphatase) with respect to detection of bone metastases. CONCLUSION: Simultaneous assessment of bone formation by BAP and of bone resorption by PYR provides a suitable tool for detection of bone metastases.

Adult↗
PubMed1995

Schönlein-Henoch purpura associated with gastric Helicobacter pylori infection.

Schönlein-Henoch purpura is characterized by palpable purpura, colicky abdominal pain, gastrointestinal hemorrhage, arthralgias, and renal involvement. Bacterial and viral infections, as well as drugs and diseases associated with immune complexes, are thought to be responsible. We describe the case of a 21-year-old woman with Schönlein-Henoch purpura and chronic active gastritis with erosions. Helicobacter pylori was found in gastric mucosa using the newly introduced, nontoxic, noninvasive 13C-urea breath test; infection was confirmed by gastric mucosal biopsy. After eradication of H. pylori with omeprazole and amoxicillin, the skin changes, gastric complaints, and proteinuria disappeared. Ten months later, Schönlein-Henoch purpura recurred. H. pylori was again detected. After therapy, H. pylori was eradicated and the clinical manifestations faded. To our knowledge, H. pylori has not previously been described as a cause of Schönlein-Henoch purpura.

Adult↗
PubMed1995

Improvement of myocardial function and metabolism in diabetic rats by the carnitine palmitoyl transferase inhibitor Etomoxir.

The effect of Etomoxir as a carnitine palmitoyl transferase I-inhibitor was investigated in normal and chronic diabetic rats. Etomoxir (18 mg/kg) was given daily for 8 days by intraperitoneal injection in order to inhibit the oxidation of fatty acids and to increase the metabolism of glucose. This carnitine palmitoyl transferase I-inhibitor significantly improved and almost normalized the decreased heart function in chronic diabetic rats. Additionally to the improvement of ventricular heart function, alterations in the conducting system of the diabetic heart were significantly ameliorated. The serum concentrations of glucose, glycerol, cholesterol, tricylglycerol, phospholipids, and beta-hydroxybutyrate were significantly lower in comparison to untreated diabetic animals, while the serum concentration of free fatty acids markedly increased. In addition to the improvement of ventricular heart function, the carnitine content of heart and liver increased in the Etomoxir-treated rats. On the other hand, the lipid content of heart and liver increased in the Etomoxir-treated rats. On the other hand, the lipid content of heart and liver increased significantly. Thus, Etomoxir may be valuable not only as a potential anti-diabetic drug but also as a lipid-lowering agent for the treatment of diabetic related dyslipoproteinaemias and, in addition, as an agent in the treatment of diabetic cardiomyopathy. However, a long-term evaluation of the metabolic consequences of the blocked carnitine palmitoyltransferase I is necessary.

Animals↗
PubMed1995

Monitoring of bone resorption after renal transplantation by measuring the urinary excretion of pyridinium cross-links.

The urinary excretion of pyridinium cross-links was measured in 70 second morning urine samples from 49 patients following renal transplantation. One and three months after renal transplantation, the urinary excretion of pyridinium cross-links was higher (p < 0.05) than at one week after transplantation. At all times after transplantation, the values for the excretion of pyridinium cross-links were correlated with the bone alkaline phosphatase concentrations (p < 0.001). However, there was no correlation between parathyrin concentrations and the values for the excretion of pyridinium cross-links (p > 0.05). This rise in the excretion of pyridinium cross-links is probably due to an increase of bone resorption caused by cyclosporin A and/or glucocorticoids. In the case of 17 urines with excretion values of pyridinium cross-links above the upper reference limit (pyridinoline equivalents, 93 mumol/mol creatinine), only 2 (12%) of the corresponding sera showed increased bone alkaline phosphatase values. In patients following renal transplantation simultaneous assessment of bone formation and bone resorption (determined from bone alkaline phosphatase serum concentrations and the excretion of pyridinium cross-links) may therefore enhance the diagnostic sensitivity for detecting effects on bone metabolism.

Adult↗
PubMed1995

An immunoblotting procedure following agarose gel electrophoresis for detection of Bence Jones proteinuria compared with immunofixation and quantitative light chain determination.

An immunoblotting procedure for the sensitive detection of Bence Jones proteinuria following agarose gel electrophoresis was developed. After immunonephelometric determination of urinary kappa and lambda light chains [employing antisera to human kappa and lambda light chains (free + bound)], urine samples (diluted to 2.5 mg/l kappa and lambda light chains, respectively) were electrophoretically separated using the Paragon system and blotted by capillary diffusion onto nitrocellulose. Rabbit anti-human kappa and lambda light chains reacted to kappa and lambda light chains attached to the membrane. Goat anti-rabbit IgG alkaline phosphatase conjugate was employed as detection system. The detection limit of the immunoblotting procedure (monoclonal component, as determined by serial dilutions) was 0.3 mg/l urine. Among 65 urine specimens received for routine testing for Bence Jones proteinuria, 32 monoclonal components (in 20 urine samples) were found by immunoblotting compared with 10 monoclonal components (in 9 urine samples) detected by immunofixation. In only 5 out of these 65 urine samples a kappa/lambda ratio (as determined immunonephelometrically) < 1 or > 5.2 (decision limits for discriminating between monoclonal and polyclonal urinary light chains; Boege F, Koehler B, Liebermann F. Eur J Clin Chem Clin Biochem 1990; 28:37-42) was observed. In conclusion, the immunoblotting method is superior to both immunofixation and immunonephelometry with respect to the diagnostic sensitivity for detection of Bence Jones proteinuria.

Antibodies, Monoclonal↗
PubMed1995

Performance characteristics of different immunoassays for determination of parathyrin (1-84) in human plasma samples.

The performance characteristics of four radioisotopically and non-radioisotopically labelled two-site immunoassays for the determination of 'intact' parathyrin in plasma samples are reported. Within-run as well as between-assay imprecision was characterized by coefficients of variation usually < 10%. Assessment of the linearity of dilution in plasma samples from patients with severe secondary hyperparathyroidism (obtained from patients with chronic renal failure prior to dialysis) revealed that an assay with N-terminal capture antibodies showed an increase of the values after dilution (p < 0.05) whereas another assay with C-terminal capture antibodies was characterized by a decrease of the values after dilution (p < 0.05). Correlation between the data obtained by the four assays and our currently used routine method (N-tact PTH from INCSTAR) revealed correlation coefficients of r > + 0.96 and slope values between 0.83 and 1.34. Determination of the analytical recovery of parathyrin (1-84) from two reference materials [First International Reference Preparation 79/500 and synthetic human parathyrin (1-84)] revealed that the recovery rates were strongly influenced by (a) the assay employed for determination of parathyrin concentrations, (b) the matrix of the diluent and (c) the reference material used. These results as well as systematic differences between the assays we examined (employing plasma samples from unselected nephrological patients) require further efforts towards a more rigorous standardization of 'intact' parathyrin assays.

Adult↗
PubMed1995

Simultaneous assessment of bone collagen synthesis and degradation in patients with different malignant tumours. Comparison with the results of 99mTc-methylene bisphosphonate bone scintigraphy.

We report on the diagnostic validity of the serum concentrations of the C-terminal propeptide of type I procollagen (a marker of bone formation) and of the urinary excretion of deoxypyridinoline (a marker of bone resorption) in a consecutive series of 89 tumour patients who were routinely examined by 99mTc-methylene bisphosphonate bone scintigraphy for detection of bone metastases. Z score analysis reveals that the discriminating power of deoxypyridinoline is superior to that of calcium excretion whereas the discriminating power of the C-terminal propeptide concentrations is inferior to that of bone alkaline phosphatase values. Accuracy (as assessed by the area under the receiver-operating characteristic curve) was 0.75 for deoxypyridinoline and 0.82 for the C-terminal propeptide. Combination of both markers did not yield an increase of accuracy (0.82) compared with the determination of the C-terminal propeptide concentrations alone. There was a correlation (r = +0.398; p < 0.0001) between C-terminal propeptide concentrations and deoxypyridinoline excretion values in the group of 89 patients examined. Further studies should be done to elucidate whether the determination of bone collagen turnover is suitable as a screening procedure for detecting bone metastases.

Adult↗
PubMed1995

External quality assessment schemes for clinical chemistry in Germany.

The external quality assessment schemes in clinical chemistry are regulated by the guidelines of the Federal Association of Physicians for Quality Assurance in Medical Laboratories (Richtlinien der Bundesärztekammer zur Qualitätssicherung in Medizinischen Laboratorien) which are part of a legal act. The basis of the mandatory quality assessment in medical laboratories is the internal accuracy and precision control. The target values for the internal accuracy and external quality control are determined by method-independent reference methods as far as possible. But for most of the analytes method-dependent assigned values are determined by expert laboratories. The decision limits for the internal and external quality control are derived from the interindividual dispersions of the analytes of a normal population (reference intervals) and should meet the medical requirements. The advantages of method-independent target values are discussed.

Chemistry, Clinical↗