[Show abstract][Hide abstract] ABSTRACT: Although human biomedical and physiological information is readily available, such information for great apes is limited. We analyzed clinical chemical biomarkers in serum samples from 277 wild- and captive-born great apes and from 312 healthy human volunteers as well as from 20 rhesus macaques. For each individual, we determined a maximum of 33 markers of heart, liver, kidney, thyroid and pancreas function, hemoglobin and lipid metabolism and one marker of inflammation. We identified biomarkers that show differences between humans and the great apes in their average level or activity. Using the rhesus macaques as an outgroup, we identified human-specific differences in the levels of bilirubin, cholinesterase and lactate dehydrogenase, and bonobo-specific differences in the level of apolipoprotein A-I. For the remaining twenty-nine biomarkers there was no evidence for lineage-specific differences. In fact, we find that many biomarkers show differences between individuals of the same species in different environments. Of the four lineage-specific biomarkers, only bilirubin showed no differences between wild- and captive-born great apes. We show that the major factor explaining the human-specific difference in bilirubin levels may be genetic. There are human-specific changes in the sequence of the promoter and the protein-coding sequence of uridine diphosphoglucuronosyltransferase 1 (UGT1A1), the enzyme that transforms bilirubin and toxic plant compounds into water-soluble, excretable metabolites. Experimental evidence that UGT1A1 is down-regulated in the human liver suggests that changes in the promoter may be responsible for the human-specific increase in bilirubin. We speculate that since cooking reduces toxic plant compounds, consumption of cooked foods, which is specific to humans, may have resulted in relaxed constraint on UGT1A1 which has in turn led to higher serum levels of bilirubin in humans.
PLoS ONE 08/2015; 10(8):e0134548. DOI:10.1371/journal.pone.0134548 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Various types of automated hematology analyzers are used in clinical laboratories. Here, we performed a side-by-side comparison of five current top of the range routine hematology analyzers in the setting of a university hospital central laboratory.
Complete blood counts (CBC), differentials, reticulocyte and nucleated red blood cell (NRBC) counts of 349 patient samples, randomly taken out of routine diagnostics, were analyzed with Cell-Dyn Sapphire (Abbott), DxH 800 (Beckman Coulter), Advia 2120i (Siemens), XE-5000 and XN-2000 (Sysmex). Inter-instrument comparison of CBCs including reticulocyte and NRBC counts and investigation of flagging quality in relation to microscopy were performed with the complete set of samples. Inter-instrument comparison of five-part differential was performed using samples without atypical cells in blood smear (n=292). Automated five-part differentials and NRBCs were additionally compared with microscopy.
The five analyzers showed a good concordance for basic blood count parameters. Correlations between instruments were less well for reticulocyte counts, NRBCs, and differentials. The poorest concordance for NRBCs with microscopy was observed for Advia 2120i (Kendall’s τ
To the best of our knowledge, this is the most comprehensive side-by-side comparison of five current top of the range routine hematology analyzers. Variable analyzer quality and parameter specific limitations must be considered in defining laboratory algorithms in clinical practice.
Clinical Chemistry and Laboratory Medicine 01/2015; 53(7). DOI:10.1515/cclm-2014-0945 · 2.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: Hevylite™ chain (HLC) assays with specificity for epitopes at the junction between heavy and light chains of intact immunoglobulins (Ig) allow quantification of Ig K/) ratios of the three major Ig classes. Calculated Ig K/ ratios outside the reference range indicate a monoclonal background. The primary aim of the present study was to analytically validate HLC assays and to investigate their diagnostic potential in relation to immunofixation electrophoresis (IFE) as the standard method for identification of monoclonal proteins (MPs). A second aim was to investigate the diagnostic potential of IILC assays in disease monitoring.
[Show abstract][Hide abstract] ABSTRACT: Background
The relationship between leptin and affective disorders is still unknown.
We measured free and bound leptin in 13 drug naïve subjects.
Leptin did not significantly differ between patients and controls.
As part of future studies, it also appears useful to distinguish between free and bound leptin.
Psychiatry Research 10/2014; 219(2). DOI:10.1016/j.psychres.2014.05.030 · 2.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Severe infections in intensive care patients show high morbidity and mortality rates. Linezolid is an antimicrobial drug frequently used in critically ill patients. Recent data indicates that there might be high variability of linezolid serum concentrations in intensive care patients receiving standard doses. This study was aimed to evaluate whether standard dosing of linezolid leads to therapeutic serum concentrations in critically ill patients.
In this prospective observational study, 30 critically ill adult patients with suspected infections received standard dosing of 600 mg linezolid intravenously twice a day. Over 4 days, multiple serum samples were obtained from each patient, in order to determine the linezolid concentrations by liquid chromatography tandem mass spectrometry.
A high variability of serum linezolid concentrations was observed (range of area under the linezolid concentration time curve over 24 hours (AUC24) 50.1 to 453.9 mg/L, median 143.3 mg*h/L; range of trough concentrations (Cmin) < 0.13 to 14.49 mg/L, median 2.06 mg/L). Furthermore, potentially subtherapeutic linezolid concentrations over 24 hours and at single time points (defined according to the literature as AUC24 < 200 mg*h/L and Cmin < 2 mg/L) were observed for 63% and 50% of the patients, respectively. Finally, potentially toxic levels (defined as AUC24 > 400 mg*h/L and Cmin > 10 mg/L) were observed for 7 of the patients.
A high variability of linezolid serum concentrations with a substantial percentage of potentially subtherapeutic levels was observed in intensive care patients. The findings suggest that therapeutic drug monitoring of linezolid might be helpful for adequate dosing of linezolid in critically ill patients.
NCT01793012. Registered 24 January 2013.
[Show abstract][Hide abstract] ABSTRACT: Background:
Liquid biobanking is an important tool for laboratory diagnostics in routine settings and clinical studies. However, the current knowledge about adequate storage conditions for different classes of biomarkers is incomplete and, in part, contradictory. Here, we performed a comprehensive study on the effects of different storage conditions on the stability of various biomarkers in human serum and plasma.
Serum and citrated plasma were aliquoted and stored at 4 °C, -20 °C, -80 °C, and <-130 °C for 0, 7, 30, and 90 days, respectively (5-10 pools/condition). Additionally, frozen aliquots were temporarily exposed to higher temperatures during storage to simulate removing individual samples. Stability was tested for 32 biomarkers from 10 different parameter classes (electrolytes, enzymes, metabolites, inert proteins, complement factors, ketone bodies, hormones, cytokines, coagulation factors, and sterols).
Biobanking at -80 °C and <-130 °C for up to 90 days did not lead to substantial changes (defined as >3 interassay coefficients of variation and p<0.01) of any biomarker concentration. In contrast, storage at 4 °C and -20 °C induced substantial changes in single biomarker concentrations in most classes. Such substantial changes were increases (<20%) in electrolytes, metabolites, and proteins, and decreases (<96%) in enzymes, ketone bodies, cytokines, and coagulation factors. Biomarker stability was minimally affected by occasional short-term thermal exposure.
Based on these results, we provide recommendations for storage conditions of up to 90 days for several biomarkers. Generally, storage at ≤-80 °C for at least 90 days including occasional short-term thermal exposure is an excellent storage condition for most biomarkers.
Clinical Chemistry and Laboratory Medicine 12/2013; 52(5):1-11. DOI:10.1515/cclm-2013-0705 · 2.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: BACKGROUNDOBJECTIVES: Chronic heart failure (CHF) is one of the most important public health concerns in the industrialized world having increasing incidence and prevalence. Although there are several studies describing the prevalence of heart failure with reduced ejection fraction (HFREF) and heart failure with normal ejection fraction (HFNEF) in selected populations, there are few data regarding the prevalence and the determinants of symptomatic heart failure in the general population.
Cross-sectional data of a population-based German sample (1,779 subjects aged 45-83 years) were analyzed to determine the prevalence and determinants of chronic SHF and HFNEF defined according to the European Society of Cardiology using symptoms, echocardiography and serum NT-proBNP. Prevalence was age-standardized to the German population as of December 31st, 2005.
The overall age-standardized prevalence of symptomatic CHF was 7.7% (95%CI 6.0-9.8) for men and 9.0% (95%CI 7.0-11.5) for women. The prevalence of CHF strongly increased with age from 3.0% among 45-54- year-old subjects to 22.0% among 75-83- year-old subjects. Symptomatic HFREF could be shown in 48% (n = 78), symptomatic HFNEF in 52% (n = 85) of subjects with CHF. The age-standardized prevalence of HFREF was 3.8 % (95%CI 2.4-5.8) for women and 4.6 % (95%CI 3.6-6.3) for men. The age-standardized prevalence of HFNEF for women and men was 5.1 % (95%CI 3.8-7.0) and 3.0 % (95%CI 2.1-4.5), respectively. Persons with CHF were more likely to have hypertension (PR = 3.4; 95%CI 1.6-7.3) or to have had a previous myocardial infarction (PR = 2.5, 95%CI 1.8-3.5).
The prevalence of symptomatic CHF appears high in this population compared with other studies. While more women were affected by HFNEF than men, more male subjects suffered from HFREF. The high prevalence of symptomatic CHF seems likely to be mainly due to the high prevalence of cardiovascular risk factors in this population.
PLoS ONE 03/2013; 8(3):e59225. DOI:10.1371/journal.pone.0059225 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Patients with phenylketonuria (PKU) have to follow a lifelong phenylalanine restricted diet. This type of diet markedly reduces the intake of saturated and unsaturated fatty acids especially long chain polyunsaturated fatty acids (LC-PUFA). Long-chain saturated fatty acids are substrates of mitochondrial fatty acid oxidation for acetyl-CoA production. LC-PUFA are discussed to affect inflammatory and haemostaseological processes in health and disease. The influence of the long term PKU diet on fatty acid metabolism with a special focus on platelet eicosanoid metabolism has been investigated in the study presented here.
12 children with PKU under good metabolic control and 8 healthy controls were included. Activated fatty acids (acylcarnitines C6-C18) in dried blood and the cholesterol metabolism in serum were analyzed by liquid chromatographic tandem mass spectrometry (LC-MS/MS). Fatty acid composition of plasma glycerophospholipids was determined by gas chromatography. LC-PUFA metabolites were analyzed in supernatants by LC-MS/MS before and after platelet activation and aggregation using a standardized protocol. Patients with PKU had significantly lower free carnitine and lower activated fatty acids in dried blood compared to controls. Phytosterols as marker of cholesterol (re-) absorption were not influenced by the dietary fatty acid restriction. Fatty acid composition in glycerophospholipids was comparable to that of healthy controls. However, patients with PKU showed significantly increased concentrations of y-linolenic acid (C18:3n-6) a precursor of arachidonic acid. In the PKU patients significantly higher platelet counts were observed. After activation with collagen platelet aggregation and thromboxane B(2) and thromboxane B(3) release did not differ from that of healthy controls.
Long-term dietary fatty acid restriction influenced the intermediates of mitochondrial beta-oxidation. No functional influence on unsaturated fatty acid metabolism and platelet aggregation in patients with PKU was detected.
PLoS ONE 08/2012; 7(8):e43021. DOI:10.1371/journal.pone.0043021 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Sepsis-associated changes of the arachidonic acid metabolism and the utility of arachidonic acid metabolites for the diagnosis of sepsis have been poorly investigated so far. Therefore, the primary objective of our study was to screen for differentially regulated arachidonic acid metabolites in septic patients using a lipopolysaccharide whole-blood model and to investigate their diagnostic potential.
Prospective, observational, single-center, clinical study.
Intensive care unit at University Hospital Leipzig.
Thirty-five patients (first cohort 25 patients, second cohort 10 patients) meeting the criteria for severe sepsis or septic shock were enrolled. Eighteen healthy volunteers (first cohort 15 subjects, second cohort 3 subjects) were enrolled as controls.
Arachidonic acid and its metabolites were investigated in supernatants of nonactivated (baseline) and lipopolysaccharide-activated heparinized whole blood of healthy subjects (n=15) and septic patients (n=25) by solid phase extraction and subsequent liquid chromatography-tandem mass spectrometry. Arachidonic acid, arachidonic acid analogues, and the cyclooxygenase-associated metabolites prostaglandin E2, 11-hydroxyeicosatetraenoic acid, and thromboxane B2 were identified as differentiating metabolites between septic patients and healthy subjects. Some of these compounds, including arachidonic acid, its analogues, and the cyclooxygenase metabolites prostaglandin E2 and thromboxane B2 differed at baseline. The inducibility of arachidonic acid and the cyclooxygenase metabolites 11-hydroxyeicosatetraenoic and prostaglandin E2 were reduced by 80% to 90% in septic patients. The degree of the inducibility was associated with severity of sepsis and clinical outcome. A reduced inducibility of COX-2 but preserved inducibility of mPGES-1 on gene expression level were confirmed in an independent cohort of septic patients (n=10) by quantitative reverse-transcription polymerase chain reaction compared to healthy controls (n=3).
Arachidonic acid metabolism is markedly affected in patients with sepsis. Our data suggest that the analysis of arachidonic acid metabolites in an in vitro whole blood activation model may be a promising approach for risk estimation in septic patients that has to be further evaluated in subsequent large-scale clinical studies.
Critical care medicine 05/2012; 40(5):1478-86. DOI:10.1097/CCM.0b013e3182416f05 · 6.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: N-terminal pro-brain natriuretic peptide (NT-proBNP) is secreted by cardiac ventricular myocytes upon pressure and volume overload and is a prognostic marker to monitor the severity of precapillary pulmonary hypertension and the extent of right heart failure. Objectives: The impact of physical exercise on NT-proBNP levels in patients with left heart disease was demonstrated previously. No data regarding patients with isolated right heart failure and the influence of acute exercise on NT-proBNP serum levels exist. Methods: Twenty patients with precapillary pulmonary hypertension were examined. Hemodynamic parameters were measured during right heart catheterization. Serum NT-proBNP of patients was measured at rest, after a 6-min walking test, during ergospirometry and during recovery, all within 7 h. Significant differences in sequential NT-proBNP values, relative changes compared to values at rest and the correlation between NT-proBNP and obtained parameters were assessed. Results: At rest, the mean serum level of NT-proBNP was 1,278 ± 998 pg/ml. The mean level of NT-proBNP at maximal exercise was increased (1,592 ± 1,219 pg/ml), whereas serum levels decreased slightly during recovery (1,518 ± 1,170 pg/ml). The relative increase of serum NT-proBNP during exercise correlated with pulmonary vascular resistance (r = 0.45; p = 0.026) and cardiac output (r = -0.5; p = 0.015). Conclusions: In this study, we demonstrated acute changes in NT-proBNP levels due to physical exercise in a small group of patients with precapillary pulmonary hypertension. Our results also confirm the predominant usefulness of NT-proBNP as an intraindividual parameter of right heart load.
[Show abstract][Hide abstract] ABSTRACT: The analysis of blood cell count including differential, is the most frequent laboratory test and has still essential diagnostic value in the diagnosis of primary or secondary diseases of the hematopoietic system. The interpretation is based on a comparison with age matched reference intervals, despite the fact that a comparison with the patients own preceding values allows a more precise statement. In the present study, blood counts and differential were performed in 1158 healthy males and females with an age ranging from 16 to 75 years were investigated using current hematology systems. The donors were examined by personnel physicians and those examining blood donors in transfusion medicine and in addition were asked via standardized questionnaire. The study resulted in reference ranges for the complete blood count, the differential blood count and reticulocytes. For several analytes, age-, gender- or analyzer-specific reference ranges were obtained. We found an age dependent decrease of the erythrocyte concentration and an increase for MCH and MCV as well as for basophils. These findings could be important for the dignosis of diseases of the elderly like myeloproliferative diseases (MPN) and myelodysplasias (MDS). Gender specific changes could be shown for the hemoglobulin-, the erythrocyte- and reticulocyte concentration, as well as for hematocrit and MCHC, being reduced in females. On the other hand, females showed significant higher levels for platelets and leukocytes, based on an increase of neutrophils and lymphocytes. The leukocytosis of smokers was confirmed for neutrophils and lymphocytes but lower than one could expect from recent studies. A multicentric study shows a broader distribution compared to unicentric data but this probably better reflects the reality and improves the applicability of the reference ranges.
[Show abstract][Hide abstract] ABSTRACT: The level of body iron storage and the erythropoietic need for iron are indicated by the serum levels of ferritin and soluble transferrin receptor (sTfR), respectively. A meta-analysis of five genome-wide association studies on sTfR and ferritin revealed novel association to the PCSK7 and TMPRSS6 loci for sTfR and the HFE locus for both parameters. The PCSK7 association was the most significant (rs236918, P = 1.1 × 10E-27) suggesting that proprotein convertase 7, the gene product of PCSK7, may be involved in sTfR generation and/or iron homeostasis. Conditioning the sTfR analyses on transferrin saturation abolished the HFE signal and substantially diminished the TMPRSS6 signal while the PCSK7 association was unaffected, suggesting that the former may be mediated by transferrin saturation whereas the PCSK7-associated effect on sTfR generation appears to be more direct.
Human Molecular Genetics 03/2011; 20(5):1042-7. DOI:10.1093/hmg/ddq538 · 6.39 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: “Thrombocytopathia” describes inherited or acquired functional disorders of platelets. The complexity of functional and metabolic processes in platelets is associated with a multitude of possible pathologic disturbances, showing a high variability in the clinical picture. The diagnosis of thrombocytopathies by existing laboratory methods is limited by variable sensitivities and specificities for various pathophysiologic backgrounds. Furthermore, the clinical evaluation of laboratory results is complex because of high intra- and interindividual variability of the platelet function. In daily routine diagnostics, a detailed patient history and clinical examination combined with aggregometry-based laboratory methods remains the central approach to diagnose a platelet function disorder.
[Show abstract][Hide abstract] ABSTRACT: Acquired hemophilia A is a rare but potentially life-threatening bleeding disorder. It is caused by the development of autoantibodies directed against coagulation factor VIII in adults or elderly patients, who do not have a personal or family history of bleeding. Case: A man (age: 76 years) on prednisone and leflunomide for polymyalgia rheumatica developed spontaneous severe haematomas. The patient was diagnosed with acquired factor VIII deficiency (FVIII activity 1.2%, FVIII inhibitor 31.7 BU). Due to the active bleeding diathesis, treatment was administered with activated prothrombin complex concentrates (FEIBA®, Baxter). Immunosuppressive treatment with a combination of oral prednisone (1 mg/kg daily) and cyclophosphamide (1,5 mg/kg daily) was administered to reduce the FVIII inhibitor. However, after two weeks of treatment, FVIII was only 3% and no clinical improvement was observed. Treatment with the anti CD20 monoclonal antibody rituximab intravenously at 375 mg/m2 once weekly for four consecutive weeks was started. The patient showed rapid clinical improvement following rituximab treatment. He achieved a complete remission defined as return to normal FVIII activity and undetectable FVIII inhibitor titer. After a follow-up of six months no relapse occurred. Conclusion: Rituximab appears an effective and well-tolerated treatment for patients with acquired haemophilia.
[Show abstract][Hide abstract] ABSTRACT: Eicosanoids play a key role in many physiological and pathological processes and might therefore serve as interesting diagnostic targets. Methods for the analysis of arachidonic acid metabolites in cells and body fluids require high sensitivity and specificity because of the very low concentrations, similar chemical structures and short half-lives of these metabolites. We established a mass spectrometric method for the simultaneous identification and quantification of arachidonic acid metabolites in human plasma samples using solid phase extraction followed by liquid chromatography (LC) and hybrid triple quadrupole-linear ion trap (QqLIT) mass spectrometry. Quantitative analysis was performed using the 4000 QTrap tandem mass spectrometer in multiple reaction monitoring (MRM) mode. As part of an independent data acquisition experiment MRMs were used as survey scans, which dependently triggered enhanced product ion (EPI) scans. Compound identification was carried out by library search using a library based on EPI spectra of standard components (prostaglandins, thromboxanes, leukotrienes and isoprostanes). The newly developed compound library enables the verification of known and structural elucidation of unknown eicosanoid metabolites in human plasma. In conclusion, our mass spectrometric method allows the simultaneous identification and quantification of arachidonic acid metabolites in one single LC-MS/MS run.