33 results on '"Felder TK"'
Search Results
2. Ketogenic diets slow melanoma growth in vivo regardless of tumor genetics and metabolic plasticity
- Author
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Weber DD, Aminzadeh-Gohari S, Thapa M, Redtenbacher AS, Catalano L, De Miranda Capeloa, Tania Isabel, Vazeille, Thibaut, Emberger M, Felder TK, Feichtinger RG, Koelblinger P, Dallmann G, Sonveaux, Pierre, Lang R, Kofler B, and UCL - SSS/IREC/FATH - Pôle de Pharmacologie et thérapeutique
- Published
- 2022
3. Associations of PPARGC1A haplotypes with plaque score but not with intima-media thickness of carotid arteries in middle-aged subjects.
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Iglseder B, Oberkofler H, Felder TK, Klein K, Paulweber B, Krempler F, Tregouet DA, Patsch W, Iglseder, Bernhard, Oberkofler, Hannes, Felder, Thomas K, Klein, Kerstin, Paulweber, Bernhard, Krempler, Franz, Tregouet, David A, and Patsch, Wolfgang
- Published
- 2006
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4. Melatonin in Human Breast Milk and Its Potential Role in Circadian Entrainment: A Nod towards Chrononutrition?
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Häusler S, Lanzinger E, Sams E, Fazelnia C, Allmer K, Binder C, Reiter RJ, and Felder TK
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- Humans, Female, Infant, Newborn, Infant Nutritional Physiological Phenomena physiology, Melatonin metabolism, Melatonin administration & dosage, Milk, Human chemistry, Milk, Human metabolism, Circadian Rhythm physiology, Breast Feeding, Lactation physiology
- Abstract
Breastfeeding is the most appropriate source of a newborn's nutrition; among the plethora of its benefits, its modulation of circadian rhythmicity with melatonin as a potential neuroendocrine transducer has gained increasing interest. Transplacental transfer assures melatonin provision for the fetus, who is devoid of melatonin secretion. Even after birth, the neonatal pineal gland is not able to produce melatonin rhythmically for several months (with an even more prolonged deficiency following preterm birth). In this context, human breast milk constitutes the main natural source of melatonin: diurnal dynamic changes, an acrophase early after midnight, and changes in melatonin concentrations according to gestational age and during the different stages of lactation have been reported. Understudied thus far are the factors impacting on (changes in) melatonin content in human breast milk and their clinical significance in chronobiological adherence in the neonate: maternal as well as environmental aspects have to be investigated in more detail to guide nursing mothers in optimal feeding schedules which probably means a synchronized instead of mistimed feeding practice. This review aims to be thought-provoking regarding the critical role of melatonin in chrononutrition during breastfeeding, highlighting its potential in circadian entrainment and therefore optimizing (neuro)developmental outcomes in the neonatal setting.
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- 2024
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5. Changing the tide in vitamin D testing: An 8-year review of a demand management approach.
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Cadamuro J, Huber-Schönauer U, Mrazek C, Hehenwarter L, Kipman U, Felder TK, and Pirich C
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- Humans, Specimen Handling, Clinical Laboratory Techniques, Vitamin D
- Abstract
Competing Interests: Potential conflict of interest None declared., (Croatian Society of Medical Biochemistry and Laboratory Medicine.)
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- 2024
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6. Ola1p trafficking indicates an interaction network between mitochondria, lipid droplets, and stress granules in times of stress.
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Kovacs M, Geltinger F, Schartel L, Pöschl S, Briza P, Paschinger M, Boros K, Felder TK, Wimmer H, Duschl J, and Rinnerthaler M
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- Mitochondria metabolism, Proteasome Endopeptidase Complex metabolism, Protein Aggregates, Stress Granules, Lipid Droplets metabolism, Saccharomyces cerevisiae metabolism
- Abstract
Protein aggregates arise naturally under normal physiological conditions, but their formation is accelerated by age or stress-induced protein misfolding. When the stressful event dissolves, these aggregates are removed by mechanisms, such as aggrephagy, chaperone-mediated autophagy, refolding attempts, or the proteasome. It was recently shown that mitochondria in yeast cells may support these primarily cytosolic processes. Protein aggregates attach to mitochondria, and misfolded proteins are transported into the matrix and degraded by mitochondria-specific proteases. Using a proximity labeling method and colocalization with an established stress granule (SG) marker, we were able to show that these mitochondria-localized aggregates that harbor the "super aggregator" Ola1p are, in fact, SGs. Our in vivo and in vitro studies have revealed that Ola1p can be transferred from mitochondria to lipid droplets (LDs). This "mitochondria to LD" aggregate transfer dampens proteotoxic effects. The LD-based protein aggregate removal system gains importance when other proteolytic systems fail. Furthermore, we were able to show that the distribution of SGs is drastically altered in LD-deficient yeast cells, demonstrating that LDs play a role in the SG life cycle., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2023
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7. Melatonin as a Therapy for Preterm Brain Injury: What Is the Evidence?
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Häusler S, Robertson NJ, Golhen K, van den Anker J, Tucker K, and Felder TK
- Abstract
Despite significant improvements in survival following preterm birth in recent years, the neurodevelopmental burden of prematurity, with its long-term cognitive and behavioral consequences, remains a significant challenge in neonatology. Neuroprotective treatment options to improve neurodevelopmental outcomes in preterm infants are therefore urgently needed. Alleviating inflammatory and oxidative stress (OS), melatonin might modify important triggers of preterm brain injury, a complex combination of destructive and developmental abnormalities termed encephalopathy of prematurity (EoP). Preliminary data also suggests that melatonin has a direct neurotrophic impact, emphasizing its therapeutic potential with a favorable safety profile in the preterm setting. The current review outlines the most important pathomechanisms underlying preterm brain injury and correlates them with melatonin's neuroprotective potential, while underlining significant pharmacokinetic/pharmacodynamic uncertainties that need to be addressed in future studies.
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- 2023
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8. The Janus-Faced Role of Lipid Droplets in Aging: Insights from the Cellular Perspective.
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Bresgen N, Kovacs M, Lahnsteiner A, Felder TK, and Rinnerthaler M
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- Animals, Drosophila melanogaster, Aging, Longevity physiology, Caenorhabditis elegans metabolism, Saccharomyces cerevisiae, Mammals, Lipid Droplets metabolism, Diabetes Mellitus, Type 2 metabolism
- Abstract
It is widely accepted that nine hallmarks-including mitochondrial dysfunction, epigenetic alterations, and loss of proteostasis-exist that describe the cellular aging process. Adding to this, a well-described cell organelle in the metabolic context, namely, lipid droplets, also accumulates with increasing age, which can be regarded as a further aging-associated process. Independently of their essential role as fat stores, lipid droplets are also able to control cell integrity by mitigating lipotoxic and proteotoxic insults. As we will show in this review, numerous longevity interventions (such as mTOR inhibition) also lead to strong accumulation of lipid droplets in Saccharomyces cerevisiae , Caenorhabditis elegans , Drosophila melanogaster , and mammalian cells, just to name a few examples. In mammals, due to the variety of different cell types and tissues, the role of lipid droplets during the aging process is much more complex. Using selected diseases associated with aging, such as Alzheimer's disease, Parkinson's disease, type II diabetes, and cardiovascular disease, we show that lipid droplets are "Janus"-faced. In an early phase of the disease, lipid droplets mitigate the toxicity of lipid peroxidation and protein aggregates, but in a later phase of the disease, a strong accumulation of lipid droplets can cause problems for cells and tissues.
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- 2023
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9. Topical Diacerein Decreases Skin and Splenic CD11c + Dendritic Cells in Psoriasis.
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Brunner SM, Ramspacher A, Rieser C, Leitner J, Heil H, Ablinger M, Tevini J, Wimmer M, Koller A, Piñón Hofbauer J, Felder TK, Bauer JW, Kofler B, Lang R, and Wally V
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- Animals, Mice, Spleen metabolism, Mice, Inbred C57BL, Skin metabolism, Cytokines metabolism, Dendritic Cells metabolism, Disease Models, Animal, Mice, Inbred BALB C, Psoriasis pathology, Dermatitis metabolism
- Abstract
Psoriasis is an inflammatory skin disease characterized by increased neo-vascularization, keratinocyte hyperproliferation, a pro-inflammatory cytokine milieu and immune cell infiltration. Diacerein is an anti-inflammatory drug, modulating immune cell functions, including expression and production of cytokines, in different inflammatory conditions. Therefore, we hypothesized that topical diacerein has beneficial effects on the course of psoriasis. The current study aimed to evaluate the effect of topical diacerein on imiquimod (IMQ)-induced psoriasis in C57BL/6 mice. Topical diacerein was observed to be safe without any adverse side effects in healthy or psoriatic animals. Our results demonstrated that diacerein significantly alleviated the psoriasiform-like skin inflammation over a 7-day period. Furthermore, diacerein significantly diminished the psoriasis-associated splenomegaly, indicating a systemic effect of the drug. Remarkably, we observed significantly reduced infiltration of CD11c
+ dendritic cells (DCs) into the skin and spleen of psoriatic mice with diacerein treatment. As CD11c+ DCs play a pivotal role in psoriasis pathology, we consider diacerein to be a promising novel therapeutic candidate for psoriasis.- Published
- 2023
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10. Diagnostic Workup of Microcytic Anemia: An Evaluation of Underuse or Misuse of Laboratory Testing in a Hospital Setting Using the AlinIQ System.
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Cadamuro J, Simundic AM, von Meyer A, Haschke-Becher E, Keppel MH, Oberkofler H, Felder TK, and Mrazek C
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- Humans, Iron, Hemoglobins analysis, Hospitals, Anemia, Iron-Deficiency diagnosis, Thalassemia diagnosis
- Abstract
Context.—: Underuse of laboratory testing has been previously investigated in preselected populations, such as documented malpractice claims. However, these numbers might not reflect real-life situations., Objective.—: To evaluate the underuse and misuse of laboratory follow-up testing in a real-life hospital patient population with microcytic anemia, using laboratory results ordered during routine patient care., Design.—: From all patients in whom a microcytic anemia was detected during routine diagnostics in 2018, all available laboratory data were collected and screened for appropriateness of diagnostic workup of iron deficiency and thalassemia. Subgroup analysis was performed for patient groups with mean corpuscular volume values 75 to 79 μm3 (group 1), 65 to 74 μm3 (group 2), and <65 μm3 (group 3)., Results.—: A total of 2244 patients with microcytic anemia were identified. Follow-up testing for iron deficiency was not performed in 761 cases (34%). For inconclusive ferritin levels due to elevated C-reactive protein results (n = 336), reticulocyte hemoglobin content or soluble transferrin receptor levels were missing in 86 cases (26%). In patients with suspected thalassemia (n = 127), follow-up testing for hemoglobin variants was not performed in 70 cases (55%). Subgroup analysis showed that the frequency of underuse of iron status as well as thalassemia/hemoglobinopathy testing decreased from group 1 to group 3. When considering relevant preexisting anemia diagnoses, laboratory tests were underused in 904 cases (40.3%)., Conclusions.—: Because 40% (n = 904) of the patients with microcytic anemia were potentially not followed up correctly, laboratory specialists are advised to act by implementing demand management strategies in collaboration with clinicians to overcome underuse of laboratory tests and to improve patient safety., (© 2023 College of American Pathologists.)
- Published
- 2023
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11. Management of intoxicated patients - a descriptive outcome analysis of 4,267 ICU patients.
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Rezar R, Jung C, Mamandipoor B, Seelmaier C, Felder TK, Lichtenauer M, Wernly S, Zwaag SM, De Lange DW, Wernly B, and Osmani V
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- Female, Hospital Mortality, Humans, Male, Respiration, Artificial, Retrospective Studies, Survivors, Critical Care, Intensive Care Units
- Abstract
Introduction: Intoxications are common in intensive care units (ICUs). The number of causative substances is large, mortality usually low. This retrospective cohort study aims to characterize differences of intoxicated compared to general ICU patients, point out variations according to causative agents, as well as to highlight differences between survivors and non-survivors among intoxicated individuals in a large-scale multi-center analysis., Methods: A total of 105,998 general ICU patients and 4,267 individuals with the admission diagnoses "overdose" and "drug toxicity" from the years 2014 and 2015 where included from the eICU Collaborative Research Database. In addition to comparing these groups with respect to baseline characteristics, intensive care measures and outcome parameters, differences between survivors and non-survivors from the intoxication group, as well as the individual groups of causative substances were investigated., Results: Intoxicated patients were younger (median 41 vs. 66 years; p<0.001), more often female (55 vs. 45%; p<0.001), and normal weighted (36% vs. 30%; p<0.001), whereas more obese individuals where observed in the other group (37 vs. 31%; p<0.001). Intoxicated individuals had a significantly lower mortality compared to general ICU patients (1% vs. 10%; aOR 0.07 95%CI 0.05-0.11; p<0.001), a finding which persisted after multivariable adjustment (aOR 0.17 95%CI 0.12-0.24; p<0.001) and persisted in all subgroups. Markers of disease severity (SOFA-score: 3 (1-5) vs. 4 (2-6) pts.; p<0.001) and frequency of vasopressor use (5 vs. 15%; p<0.001) where lower, whereas rates of mechanical ventilation where higher (24 vs. 26%; p<0.001) in intoxicated individuals. There were no differences with regard to renal replacement therapy in the first three days (3 vs. 4%; p=0.26). In sensitivity analysis (interactions for age, sex, ethnicity, hospital category, maximum initial lactate, mechanical ventilation, and vasopressor use), a trend towards lower mortality in intoxicated patients persisted in all subgroups., Conclusion: This large-scale retrospective analysis indicates a significantly lower mortality of intoxicated individuals compared to general ICU patients., (© 2022. The Author(s).)
- Published
- 2022
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12. Changing Metabolic Patterns along the Colorectal Adenoma-Carcinoma Sequence.
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Tevini J, Eder SK, Huber-Schönauer U, Niederseer D, Strebinger G, Gostner JM, Aigner E, Datz C, and Felder TK
- Abstract
Colorectal cancer (CRC) is a major public health burden and one of the leading causes of cancer-related deaths worldwide. Screening programs facilitate early diagnosis and can help to reduce poor outcomes. Serum metabolomics can extract vital molecular information that may increase the sensitivity and specificity of colonoscopy in combination with histopathological examination. The present study identifies serum metabolite patterns of treatment-naïve patients, diagnosed with either advanced adenoma (AA) or CRC in colonoscopy screenings, in the framework of the SAKKOPI (Salzburg Colon Cancer Prevention Initiative) program. We used a targeted flow injection analysis and liquid chromatography-tandem mass spectrometry metabolomics approach (FIA- and LC-MS/MS) to characterise the serum metabolomes of an initial screening cohort and two validation cohorts (in total 66 CRC, 76 AA and 93 controls). The lipidome was significantly perturbed, with a proportion of lipid species being downregulated in CRC patients, as compared to AA and controls. The predominant alterations observed were in the levels of lyso-lipids, glycerophosphocholines and acylcarnitines, but additionally, variations in the quantity of hydroxylated sphingolipids could be detected. Changed amino acid metabolism was restricted mainly to metabolites of the arginine/dimethylarginine/NO synthase pathway. The identified metabolic divergences observed in CRC set the foundation for mechanistic studies to characterise biochemical pathways that become deregulated during progression through the adenoma to carcinoma sequence and highlight the key importance of lipid metabolites. Biomarkers related to these pathways could improve the sensitivity and specificity of diagnosis, as well as the monitoring of therapies.
- Published
- 2022
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13. Immunometabolism as predictor of frailty.
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Gostner JM, Laffon B, and Felder TK
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- Aged, Aging immunology, Aging metabolism, Frailty etiology, Humans, Immune System physiology, Tryptophan metabolism, Frailty immunology, Immune System metabolism, Immunosenescence
- Published
- 2021
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14. Soluble suppression of tumorigenicity 2 as outcome predictor after cardiopulmonary resuscitation: an observational prospective study.
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Rezar R, Paar V, Seelmaier C, Pretsch I, Schwaiger P, Kopp K, Kaufmann R, Felder TK, Prinz E, Gemes G, Pistulli R, Hoppe UC, Wernly B, and Lichtenauer M
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- Aged, Biomarkers blood, Female, Humans, Male, Middle Aged, Prospective Studies, Cardiopulmonary Resuscitation mortality, Interleukin-1 Receptor-Like 1 Protein blood
- Abstract
Prognostication after cardiopulmonary resuscitation (CPR) is complex. Novel biomarkers like soluble suppression of tumorigenicity 2 (sST2) may provide an objective approach. A total of 106 post-CPR patients were included in this single-center observational prospective study. Serum sST2 levels were obtained 24 h after admission. Individuals were assigned to two groups: patients below and above the overall cohort's median sST2 concentration. Primary outcome was a combined endpoint at 6 months (death or Cerebral Performance Category > 2); secondary endpoint 30-day mortality. A uni- and multivariate logistic regression analysis were conducted. Elevated sST2-levels were associated with an increased risk for the primary outcome (OR 1.011, 95% CI 1.004-1.019, p = 0.004), yet no patients with poor neurological outcome were observed at 6 months. The optimal empirical cut-off for sST2 was 46.15 ng/ml (sensitivity 81%, specificity 53%, AUC 0.69). Levels above the median (> 53.42 ng/ml) were associated with higher odds for both endpoints (death or CPC > 2 after 6 months: 21% vs. 49%, OR 3.59, 95% CI 1.53-8.45, p = 0.003; death after 30 days: 17% vs. 43.3%, OR 3.75, 95% CI 1.52-9.21, p = 0.003). A positive correlation of serum sST2 after CPR with mortality at 30 days and 6 months after cardiac arrest could be demonstrated., (© 2021. The Author(s).)
- Published
- 2021
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15. Laboratory Demand Management Strategies-An Overview.
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Mrazek C, Haschke-Becher E, Felder TK, Keppel MH, Oberkofler H, and Cadamuro J
- Abstract
Inappropriate laboratory test selection in the form of overutilization as well as underutilization frequently occurs despite available guidelines. There is broad approval among laboratory specialists as well as clinicians that demand management strategies are useful tools to avoid this issue. Most of these tools are based on automated algorithms or other types of machine learning. This review summarizes the available demand management strategies that may be adopted to local settings. We believe that artificial intelligence may help to further improve these available tools.
- Published
- 2021
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16. Friend or Foe: Lipid Droplets as Organelles for Protein and Lipid Storage in Cellular Stress Response, Aging and Disease.
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Geltinger F, Schartel L, Wiederstein M, Tevini J, Aigner E, Felder TK, and Rinnerthaler M
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- Animals, Endoplasmic Reticulum metabolism, Humans, Aging metabolism, Lipid Droplets metabolism, Lipid Metabolism, Neurodegenerative Diseases metabolism, Proteome metabolism, Stress, Physiological
- Abstract
Lipid droplets (LDs) were considered as a mere lipid storage organelle for a long time. Recent evidence suggests that LDs are in fact distinct and dynamic organelles with a specialized proteome and functions in many cellular roles. As such, LDs contribute to cellular signaling, protein and lipid homeostasis, metabolic diseases and inflammation. In line with the multitude of functions, LDs interact with many cellular organelles including mitochondria, peroxisomes, lysosomes, the endoplasmic reticulum and the nucleus. LDs are highly mobile and dynamic organelles and impaired motility disrupts the interaction with other organelles. The reduction of interorganelle contacts results in a multitude of pathophysiologies and frequently in neurodegenerative diseases. Contacts not only supply lipids for β-oxidation in mitochondria and peroxisomes, but also may include the transfer of toxic lipids as well as misfolded and harmful proteins to LDs. Furthermore, LDs assist in the removal of protein aggregates when severe proteotoxic stress overwhelms the proteasomal system. During imbalance of cellular lipid homeostasis, LDs also support cellular detoxification. Fine-tuning of LD function is of crucial importance and many diseases are associated with dysfunctional LDs. We summarize the current understanding of LDs and their interactions with organelles, providing a storage site for harmful proteins and lipids during cellular stress, aging inflammation and various disease states.
- Published
- 2020
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17. Errors within the total laboratory testing process, from test selection to medical decision-making - A review of causes, consequences, surveillance and solutions.
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Mrazek C, Lippi G, Keppel MH, Felder TK, Oberkofler H, Haschke-Becher E, and Cadamuro J
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- Centrifugation, Europe, Humans, Medical Overuse, Patient Safety, Quality Control, Quality Indicators, Health Care, Reference Values, Reproducibility of Results, Clinical Decision-Making, Clinical Laboratory Techniques standards, Medical Errors prevention & control, Phlebotomy standards
- Abstract
Laboratory analyses are crucial for diagnosis, follow-up and treatment decisions. Since mistakes in every step of the total testing process may potentially affect patient safety, a broad knowledge and systematic assessment of laboratory errors is essential for future improvement. In this review, we aim to discuss the types and frequencies of potential errors in the total testing process, quality management options, as well as tentative solutions for improvement. Unlike most currently available reviews on this topic, we also include errors in test-selection, reporting and interpretation/action of test results. We believe that laboratory specialists will need to refocus on many process steps belonging to the extra-analytical phases, intensifying collaborations with clinicians and supporting test selection and interpretation. This would hopefully lead to substantial improvements in these activities, but may also bring more value to the role of laboratory specialists within the health care setting., Competing Interests: Potential conflict of interest: None declared., (Croatian Society of Medical Biochemistry and Laboratory Medicine.)
- Published
- 2020
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18. Low rate of new-onset primary biliary cholangitis in a cohort of anti-mitochondrial antibody-positive subjects over six years of follow-up.
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Zandanell S, Strasser M, Feldman A, Tevini J, Strebinger G, Niederseer D, Pohla-Gubo G, Huber-Schönauer U, Ruhaltinger S, Paulweber B, Datz C, Felder TK, and Aigner E
- Subjects
- Adult, Aged, Aged, 80 and over, Female, Follow-Up Studies, Humans, Immunoblotting, Liver immunology, Liver Cirrhosis, Biliary diagnosis, Liver Cirrhosis, Biliary immunology, Male, Middle Aged, Autoantibodies immunology, Liver Cirrhosis, Biliary epidemiology, Mitochondria immunology
- Abstract
Background and Aims: Anti-mitochondrial antibodies (AMA) are closely linked to primary biliary cholangitis (PBC). The prevalence of AMA in the general population is low, and AMA positivity may precede PBC. We aimed to determine the natural history of subjects with positive AMA., Methods: In total, 302 patients were tested AMA-positive over a ten-year period. Of these, immunoblotting confirmed specific AMA in 184 (29 male, 155 female, age 59.6 ± 14.1 years). These subjects were invited to our liver outpatient clinic for clinical and biochemical re-evaluation. Detailed clinical history data were additionally collected from the hospital computer system and by telephone. The subsequent course with regard to mortality, liver-related morbidity, extrahepatic co-morbidities and effectiveness of PBC treatment was determined in 150 subjects (81.5%)., Results: After 5.8 ± 5.6 years of follow-up (FU), of 184 AMA-positive subjects, 28 subjects (15.2%; liver-related mortality n = 5) were deceased, and 122 subjects (66.3%) completed FU while 34 subjects (18.5%) were not available for FU. The 122 patients who completed FU were 63 patients with established PBC, six de novo cases of PBC (10.2% of 59 initially at risk), 42 (34.4%) subjects were still AMA-positive without PBC, and 11 (9.0%) subjects were AMA-negative at FU., Conclusions: Anti-mitochondrial antibodies-positive patients without PBC at baseline infrequently developed PBC over six years of FU. AMA positivity represented a transient serological autoimmune phenomenon in a significant proportion of subjects., (© 2019 The Authors. Journal of Internal Medicine published by John Wiley & Sons Ltd on behalf of Association for Publication of The Journal of Internal Medicine.)
- Published
- 2020
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19. Heart-Type Fatty Acid-Binding Protein (H-FABP) and its Role as a Biomarker in Heart Failure: What Do We Know So Far?
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Rezar R, Jirak P, Gschwandtner M, Derler R, Felder TK, Haslinger M, Kopp K, Seelmaier C, Granitz C, Hoppe UC, and Lichtenauer M
- Abstract
Background: Heart failure (HF) remains one of the leading causes of death to date despite extensive research funding. Various studies are conducted every year in an attempt to improve diagnostic accuracy and therapy monitoring. The small cytoplasmic heart-type fatty acid-binding protein (H-FABP) has been studied in a variety of disease entities. Here, we provide a review of the available literature on H-FABP and its possible applications in HF. Methods: Literature research using PubMed Central was conducted. To select possible studies for inclusion, the authors screened all available studies by title and, if suitable, by abstract. Relevant manuscripts were read in full text., Results: In total, 23 studies regarding H-FABP in HF were included in this review., Conclusion: While, algorithms already exist in the area of risk stratification for acute pulmonary embolism, there is still no consensus for the routine use of H-FABP in daily clinical practice in HF. At present, the strongest evidence exists for risk evaluation of adverse cardiac events. Other future applications of H-FABP may include early detection of ischemia, worsening of renal failure, and long-term treatment planning., Competing Interests: The authors declare no conflict of interest.
- Published
- 2020
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20. The endogenous cardiotonic steroid Marinobufagenin and decline in estimated glomerular filtration rate at follow-up in patients with arterial hypertension.
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Keppel MH, Piecha G, März W, Cadamuro J, Auer S, Felder TK, Mrazek C, Oberkofler H, Trummer C, Grübler MR, Schwetz V, Verheyen N, Pandis M, Borzan V, Haschke-Becher E, Tomaschitz A, and Pilz S
- Subjects
- Adult, Aged, Albuminuria blood, Albuminuria physiopathology, Animals, Biomarkers blood, Cardiotonic Agents blood, Enzyme Inhibitors blood, Female, Follow-Up Studies, Humans, Male, Middle Aged, Proteinuria blood, Proteinuria physiopathology, Rats, Renal Insufficiency, Chronic blood, Renal Insufficiency, Chronic physiopathology, Bufanolides blood, Glomerular Filtration Rate physiology, Hypertension blood, Hypertension physiopathology
- Abstract
Background: Marinobufagenin (MBG) is an endogenous cardiotonic steroid (CTS) that inhibits the Na+/K+-ATPase. Human MBG is significantly increased in end-stage renal disease and immunization against MBG attenuates cardiovascular fibrosis in a rat model of uremic cardiomyopathy. Mineralocorticoid antagonists (MRA) block MBG binding sites and decrease proteinuria in chronic kidney disease (CKD) patients. We therefore aimed to investigate the association of MBG and albuminuria, as a marker of renal damage, as well as MBG and decline of glomerular filtration rate (GFR)., Methods: The Graz endocrine causes of hypertension (GECOH) study is a single center study of adults routinely referred for screening of endocrine hypertension. Plasma MBG was measured by an enzyme-linked immunoassay, and in a post-hoc analysis, follow-up creatinine levels were obtained. Patients with proteinuria >3.5g/day at baseline were excluded from further evaluation., Results: We measured MBG concentrations in 40 hypertensive subjects and excluded one patient due to pre-existing proteinuria. Plasma MBG was significantly correlated with albuminuria (Spearman ρ = .357; p = .028) and proteinuria (ρ = .336; p = .039). In linear regression analysis, the association remained significant after adjustment for age, sex, and BMI (β = .306; p = .036), and for mean systolic blood pressure (β = .352; p = .034). In follow-up analyses (N = 30), MBG was significantly associated with decline in GFR after adjustment for time-to-follow-up (β = -.374; p = .042)., Conclusion: The findings suggest that MBG plasma concentrations were associated with albuminuria as well as decline in kidney function. Whether MBG predicts hard renal endpoints warrants further investigations., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
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21. Basal pharmacokinetic parameters of topically applied diacerein in pediatric patients with generalized severe epidermolysis bullosa simplex.
- Author
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Ablinger M, Felder TK, Wimmer M, Zauner R, Hofbauer P, Lettner T, Wolkersdorfer M, Lagler FB, Diem A, Bauer JW, and Wally V
- Subjects
- Administration, Topical, Anthraquinones administration & dosage, Anthraquinones chemistry, Anti-Inflammatory Agents administration & dosage, Anti-Inflammatory Agents chemistry, Humans, Male, Molecular Structure, Anthraquinones pharmacokinetics, Anthraquinones therapeutic use, Anti-Inflammatory Agents pharmacokinetics, Anti-Inflammatory Agents therapeutic use, Epidermolysis Bullosa Simplex drug therapy
- Abstract
Generalized severe epidermolysis bullosa simplex (EBS-gen sev) is caused by mutations within either the KRT5 or KRT14 gene, phenotypically resulting in blistering and wounding of the skin and mucous membranes after minor mechanical friction. In a clinical phase 2/3 trial, diacerein has recently been shown to significantly reduce blister numbers upon topical application. In this study we addressed basic pharmacokinetic parameters of locally applied diacerein in vitro and in vivo. Ex vivo experiments using a Franz diffusion cell confirmed the uptake and bio-transformation of diacerein to rhein in a porcine skin model. Rhein, the active metabolite of diacerein, was also detected in both urine and serum samples of two EBS-gen sev patients who topically applied a 1% diacerein ointment over a period of 4 weeks. The accumulated systemic levels of rhein in EBS-gen sev patients were lower than reported levels after oral application. These preliminary findings point towards the uptake and prolonged persistance of diacerein / rhein within the intended target organ - the skin. Further, they imply an acceptable safety profile at the systemic level. TRIAL REGISTRATION: DRKS. DRKS00005412 . Registered 6 November 2013.
- Published
- 2018
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22. Influence of centrifugation conditions on the results of 77 routine clinical chemistry analytes using standard vacuum blood collection tubes and the new BD-Barricor tubes.
- Author
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Cadamuro J, Mrazek C, Leichtle AB, Kipman U, Felder TK, Wiedemann H, Oberkofler H, Fiedler GM, and Haschke-Becher E
- Subjects
- Centrifugation, Chemistry, Clinical instrumentation, Humans, Inorganic Chemicals blood, Organic Chemicals blood, Blood Specimen Collection instrumentation, Chemistry, Clinical methods
- Abstract
Introduction: Although centrifugation is performed in almost every blood sample, recommendations on duration and g-force are heterogeneous and mostly based on expert opinions. In order to unify this step in a fully automated laboratory, we aimed to evaluate different centrifugation settings and their influence on the results of routine clinical chemistry analytes., Materials and Methods: We collected blood from 41 healthy volunteers into BD Vacutainer PST II-heparin-gel- (LiHepGel), BD Vacutainer SST II-serum-, and BD Vacutainer Barricor heparin-tubes with a mechanical separator (LiHepBar). Tubes were centrifuged at 2000xg for 10 minutes and 3000xg for 7 and 5 minutes, respectively. Subsequently 60 and 21 clinical chemistry analytes were measured in plasma and serum samples, respectively, using a Roche COBAS instrument., Results: High sensitive Troponin T, pregnancy-associated plasma protein A, ß human chorionic gonadotropin and rheumatoid factor had to be excluded from statistical evaluation as many of the respective results were below the measuring range. Except of free haemoglobin (fHb) measurements, no analyte result was altered by the use of shorter centrifugation times at higher g-forces. Comparing LiHepBar to LiHepGel tubes at different centrifugation setting, we found higher lactate-dehydrogenase (LD) (P = 0.003 to < 0.001) and lower bicarbonate values (P = 0.049 to 0.008) in the latter., Conclusions: Serum and heparin samples may be centrifuged at higher speed (3000xg) for a shorter amount of time (5 minutes) without alteration of the analytes tested in this study. When using LiHepBar tubes for blood collection, a separate LD reference value might be needed., Competing Interests: Potential conflict of interest: Janne Cadamuro received a personal fee as guest member of a Becton Dickinson Advisory board meeting.
- Published
- 2018
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23. The ketogenic diet is not feasible as a therapy in a CD-1 nu/nu mouse model of renal cell carcinoma with features of Stauffer's syndrome.
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Vidali S, Aminzadeh-Gohari S, Feichtinger RG, Vatrinet R, Koller A, Locker F, Rutherford T, O'Donnell M, Stöger-Kleiber A, Lambert B, Felder TK, Sperl W, and Kofler B
- Abstract
The ketogenic diet (KD), a high-fat low-carbohydrate diet, has shown some efficacy in the treatment of certain types of tumors such as brain tumors and neuroblastoma. These tumors are characterized by the Warburg effect. Because renal cell carcinoma (RCC) presents similar energetic features as neuroblastoma, KD might also be effective in the treatment of RCC. To test this, we established xenografts with RCC 786-O cells in CD-1 nu/nu mice and then randomized them to a control diet or to KDs with different triglyceride contents. Although the KDs tended to reduce tumor growth, mouse survival was dramatically reduced due to massive weight loss. A possible explanation comes from observations of human RCC patients, who often experience secondary non-metastatic hepatic dysfunction due to secretion of high levels of inflammatory cytokines by the RCCs. Measurement of the mRNA levels of tumor necrosis factor alpha (TNFα) and interleukin-6 revealed high expression in the RCC xenografts compared to the original 786-O cells. The expression of TNFα, interleukin-6 and C-reactive protein were all increased in the livers of tumor-bearing mice, and KD significantly boosted their expression. KDs did not cause weight loss or liver inflammation in healthy mice, suggesting that KDs are per se safe, but might be contraindicated in the treatment of RCC patients presenting with Stauffer's syndrome, because they potentially worsen the associated hepatic dysfunction., Competing Interests: CONFLICTS OF INTEREST The authors state no conflicts of interest.
- Published
- 2017
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24. What´s floating on my plasma?
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Cadamuro J, Wiedemann H, Felder TK, Mrazek C, Kipman U, Hannes O, and Haschke-Becher E
- Subjects
- Blood Chemical Analysis methods, Blood Platelets chemistry, Blood Specimen Collection instrumentation, Blood Specimen Collection methods, Cholesterol chemistry, Fats chemistry, Fibrinogen chemistry, Gels chemistry, Humans, Hydrogen-Ion Concentration, Leukocytes chemistry, Particulate Matter chemistry, Reproducibility of Results, Thrombosis, Blood Chemical Analysis standards, Blood Glucose analysis, Blood Specimen Collection standards, Heparin chemistry
- Abstract
We report on a preanalytical issue we encountered during routine clinical chemistry analyses, potentially leading to deviated analysis results and believe that it might help other laboratories to overcome similar problems. In a heparin-gel tube we measured an implausible glucose value of 0.06 mmol/L. Re-measurement of the same sample resulted in a glucose value of 5.4 mmol/L. After excluding an analytical error, we inspected the sample closer and found a white material as well as fatty droplets floating on the surface of the plasma tube. Evaluation of these structures revealed that the white particulate matter (WPM) consisted of fibrinogen, platelets and leukocytes and the fatty droplets most probably originated from the separator gel. We concluded that these structures formed a temporary clot in the instruments pipetting needle thereby altering the sampling volume and subsequently the measured glucose value. The formation of WPM might be attributable to high speed centrifugation, high cholesterol levels, the gel formulation or a combination of several issues such as temperature, heparin concentration, pH and patient-specific factors. The gel droplets were most probably caused by an aberrant gel formulation in combination with an improper storage of the empty tubes on the wards prior to phlebotomy. After adding an additional instrument cleansing cycle and changing to another batch of heparin tubes the problems could be significantly reduced., Competing Interests: Potential conflict of interest: None declared.
- Published
- 2017
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25. The Human NADPH Oxidase, Nox4, Regulates Cytoskeletal Organization in Two Cancer Cell Lines, HepG2 and SH-SY5Y.
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Auer S, Rinnerthaler M, Bischof J, Streubel MK, Breitenbach-Koller H, Geisberger R, Aigner E, Cadamuro J, Richter K, Sopjani M, Haschke-Becher E, Felder TK, and Breitenbach M
- Abstract
NADPH oxidases of human cells are not only functional in defense against invading microorganisms and for oxidative reactions needed for specialized biosynthetic pathways but also during the past few years have been established as signaling modules. It has been shown that human Nox4 is expressed in most somatic cell types and produces hydrogen peroxide, which signals to remodel the actin cytoskeleton. This correlates well with the function of Yno1, the only NADPH oxidase of yeast cells. Using two established tumor cell lines, which are derived from hepatic and neuroblastoma tumors, respectively, we are showing here that in both tumor models Nox4 is expressed in the ER (like the yeast NADPH oxidase), where according to published literature, it produces hydrogen peroxide. Reducing this biochemical activity by downregulating Nox4 transcription leads to loss of F-actin stress fibers. This phenotype is reversible by adding hydrogen peroxide to the cells. The effect of the Nox4 silencer RNA is specific for this gene as it does not influence the expression of Nox2. In the case of the SH-SY5Y neuronal cell line, Nox4 inhibition leads to loss of cell mobility as measured in scratch assays. We propose that inhibition of Nox4 (which is known to be strongly expressed in many tumors) could be studied as a new target for cancer treatment, in particular for inhibition of metastasis.
- Published
- 2017
- Full Text
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26. Metabolomic profiling identifies potential pathways involved in the interaction of iron homeostasis with glucose metabolism.
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Stechemesser L, Eder SK, Wagner A, Patsch W, Feldman A, Strasser M, Auer S, Niederseer D, Huber-Schönauer U, Paulweber B, Zandanell S, Ruhaltinger S, Weghuber D, Haschke-Becher E, Grabmer C, Rohde E, Datz C, Felder TK, and Aigner E
- Subjects
- Adult, Blood Glucose metabolism, Citrulline blood, Citrulline metabolism, Cross-Sectional Studies, Diabetes Mellitus, Type 2 metabolism, Female, Ferritins analysis, Ferritins blood, Ferritins metabolism, Glucose Tolerance Test, Homeostasis, Humans, Insulin Resistance physiology, Iron blood, Male, Metabolic Syndrome metabolism, Metabolomics methods, Middle Aged, Obesity blood, Sarcosine blood, Sarcosine metabolism, Glucose metabolism, Iron metabolism
- Abstract
Objective: Elevated serum ferritin has been linked to type 2 diabetes (T2D) and adverse health outcomes in subjects with the Metabolic Syndrome (MetS). As the mechanisms underlying the negative impact of excess iron have so far remained elusive, we aimed to identify potential links between iron homeostasis and metabolic pathways., Methods: In a cross-sectional study, data were obtained from 163 patients, allocated to one of three groups: (1) lean, healthy controls (n = 53), (2) MetS without hyperferritinemia (n = 54) and (3) MetS with hyperferritinemia (n = 56). An additional phlebotomy study included 29 patients with biopsy-proven iron overload before and after iron removal. A detailed clinical and biochemical characterization was obtained and metabolomic profiling was performed via a targeted metabolomics approach., Results: Subjects with MetS and elevated ferritin had higher fasting glucose (p < 0.001), HbA1c (p = 0.035) and 1 h glucose in oral glucose tolerance test (p = 0.002) compared to MetS subjects without iron overload, whereas other clinical and biochemical features of the MetS were not different. The metabolomic study revealed significant differences between MetS with high and low ferritin in the serum concentrations of sarcosine, citrulline and particularly long-chain phosphatidylcholines. Methionine, glutamate, and long-chain phosphatidylcholines were significantly different before and after phlebotomy (p < 0.05 for all metabolites)., Conclusions: Our data suggest that high serum ferritin concentrations are linked to impaired glucose homeostasis in subjects with the MetS. Iron excess is associated to distinct changes in the serum concentrations of phosphatidylcholine subsets. A pathway involving sarcosine and citrulline also may be involved in iron-induced impairment of glucose metabolism.
- Published
- 2016
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27. Topical diacerein for epidermolysis bullosa: a randomized controlled pilot study.
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Wally V, Kitzmueller S, Lagler F, Moder A, Hitzl W, Wolkersdorfer M, Hofbauer P, Felder TK, Dornauer M, Diem A, Eiler N, and Bauer JW
- Subjects
- Administration, Topical, Adolescent, Adult, Blister drug therapy, Child, Double-Blind Method, Epidermolysis Bullosa Simplex genetics, Epidermolysis Bullosa Simplex pathology, Humans, Keratin-14 genetics, Middle Aged, Pilot Projects, Treatment Outcome, Young Adult, Anthraquinones administration & dosage, Anthraquinones therapeutic use, Anti-Inflammatory Agents administration & dosage, Anti-Inflammatory Agents therapeutic use, Epidermolysis Bullosa Simplex drug therapy
- Abstract
Blistering in epidermolysis bullosa simplex type Dowling-Meara (EBS-DM) is associated with an inflammatory phenotype, which can be disrupted by diacerein in vitro. In this pilot study we hypothesized, that a topical formulation of diacerein 1% reduces blistering. Five patients initially applied diacerein underneath both armpits. Then, each participant received 1% diacerein-cream for one armpit, and placebo for the other (randomized withdrawal). The number of blisters was reduced significantly (left: -78%; right: -66% of baseline) within two weeks and remained significantly below the initial level even during withdrawal in four patients. These findings point to a relevant effect of diacerein and provide important information for a confirmative study.
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- 2013
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28. Yno1p/Aim14p, a NADPH-oxidase ortholog, controls extramitochondrial reactive oxygen species generation, apoptosis, and actin cable formation in yeast.
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Rinnerthaler M, Büttner S, Laun P, Heeren G, Felder TK, Klinger H, Weinberger M, Stolze K, Grousl T, Hasek J, Benada O, Frydlova I, Klocker A, Simon-Nobbe B, Jansko B, Breitenbach-Koller H, Eisenberg T, Gourlay CW, Madeo F, Burhans WC, and Breitenbach M
- Subjects
- Amino Acid Sequence, Caspases genetics, Caspases metabolism, Cytoskeleton metabolism, Endoplasmic Reticulum enzymology, Green Fluorescent Proteins genetics, Green Fluorescent Proteins metabolism, Microscopy, Fluorescence, Microscopy, Phase-Contrast, Molecular Sequence Data, Mutation, NADPH Oxidases classification, NADPH Oxidases genetics, Open Reading Frames genetics, Phylogeny, Saccharomyces cerevisiae genetics, Saccharomyces cerevisiae Proteins genetics, Superoxides metabolism, Actins metabolism, Apoptosis, NADPH Oxidases metabolism, Reactive Oxygen Species metabolism, Saccharomyces cerevisiae metabolism, Saccharomyces cerevisiae Proteins metabolism
- Abstract
The large protein superfamily of NADPH oxidases (NOX enzymes) is found in members of all eukaryotic kingdoms: animals, plants, fungi, and protists. The physiological functions of these NOX enzymes range from defense to specialized oxidative biosynthesis and to signaling. In filamentous fungi, NOX enzymes are involved in signaling cell differentiation, in particular in the formation of fruiting bodies. On the basis of bioinformatics analysis, until now it was believed that the genomes of unicellular fungi like Saccharomyces cerevisiae and Schizosaccharomyces pombe do not harbor genes coding for NOX enzymes. Nevertheless, the genome of S. cerevisiae contains nine ORFs showing sequence similarity to the catalytic subunits of mammalian NOX enzymes, only some of which have been functionally assigned as ferric reductases involved in iron ion transport. Here we show that one of the nine ORFs (YGL160W, AIM14) encodes a genuine NADPH oxidase, which is located in the endoplasmic reticulum (ER) and produces superoxide in a NADPH-dependent fashion. We renamed this ORF YNO1 (yeast NADPH oxidase 1). Overexpression of YNO1 causes YCA1-dependent apoptosis, whereas deletion of the gene makes cells less sensitive to apoptotic stimuli. Several independent lines of evidence point to regulation of the actin cytoskeleton by reactive oxygen species (ROS) produced by Yno1p.
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- 2012
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29. Characterization of novel peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) isoform in human liver.
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Felder TK, Soyal SM, Oberkofler H, Hahne P, Auer S, Weiss R, Gadermaier G, Miller K, Krempler F, Esterbauer H, and Patsch W
- Subjects
- 8-Bromo Cyclic Adenosine Monophosphate pharmacology, Animals, Blotting, Northern, Chromatin Immunoprecipitation, Dexamethasone pharmacology, Female, Gene Expression drug effects, Gene Expression genetics, Genotype, Heat-Shock Proteins genetics, Hep G2 Cells, Humans, Immunoblotting, In Vitro Techniques, Mice, Microscopy, Fluorescence, Molecular Sequence Data, Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha, Protein Isoforms genetics, RNA, Messenger genetics, Rats, Transcription Factors genetics, Heat-Shock Proteins metabolism, Liver metabolism, Protein Isoforms metabolism, Transcription Factors metabolism
- Abstract
Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) is a transcriptional coactivator that contributes to the regulation of numerous transcriptional programs including the hepatic response to fasting. Mechanisms at transcriptional and post-transcriptional levels allow PGC-1α to support distinct biological pathways. Here we describe a novel human liver-specific PGC-1α transcript that results from alternative promoter usage and is induced by FOXO1 as well as glucocorticoids and cAMP-response element-binding protein signaling but is not present in other mammals. Hepatic tissue levels of novel and wild-type transcripts were similar but were only moderately associated (p < 0.003). Novel mRNA levels were associated with a polymorphism located in its promoter region, whereas wild-type transcript levels were not. Furthermore, hepatic PCK1 mRNA levels exhibited stronger associations with the novel than with the wild-type transcript levels. Except for a deletion of 127 amino acids at the N terminus, the protein, termed L-PGC-1α, is identical to PGC-1α. L-PGC-1α was localized in the nucleus and showed coactivation properties that overlap with those of PGC-1α. Collectively, our data support a role of L-PGC-1α in gluconeogenesis, but functional differences predicted from the altered structure suggest that L-PGC-1α may have arisen to adapt PGC-1α to more complex metabolic pathways in humans.
- Published
- 2011
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30. Cardiac troponins T and I: reproducible discrepancies in the clinical setting.
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Cadamuro J, Felder TK, and Patsch W
- Subjects
- Adult, Aged, Aged, 80 and over, Biomarkers blood, Female, Humans, Male, Middle Aged, Reproducibility of Results, Retrospective Studies, Troponin I blood, Troponin T blood
- Published
- 2011
- Full Text
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31. Hepatic adiponectin receptors (ADIPOR) 1 and 2 mRNA and their relation to insulin resistance in obese humans.
- Author
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Felder TK, Hahne P, Soyal SM, Miller K, Höffinger H, Oberkofler H, Krempler F, and Patsch W
- Subjects
- Adiponectin blood, Adult, Body Mass Index, Female, Forkhead Box Protein O1, Forkhead Transcription Factors genetics, Forkhead Transcription Factors metabolism, Gene Expression, Humans, Male, Obesity genetics, Obesity physiopathology, RNA, Messenger genetics, RNA, Messenger metabolism, Receptors, Adiponectin genetics, Risk Factors, Insulin Resistance genetics, Obesity metabolism, Receptors, Adiponectin metabolism
- Abstract
Objective: Adiponectin signalling attenuates insulin resistance (IR) and steatosis hepatis in animal models. As adiponectin receptor (ADIPOR)1 and ADIPOR2 are critical components in the adiponectin signalling cascade, we studied hepatic ADIPOR1/2 mRNA levels in humans and their relation to IR., Design: We determined metabolic risk factors and levels of hepatic mRNA transcribed from ADIPOR1, ADIPOR2 and FOXO1, a putative up-stream regulator, in 43 and 34 obese subjects with low and high homeostasis model assessment-IR, respectively., Results: Plasma adiponectin and metabolic risk factors showed associations with IR as expected. Both hepatic ADIPOR1 and ADIPOR2 mRNA expression levels were higher in insulin-resistant subjects (P<0.0035). ADIPOR1 mRNA correlated with FOXO1 mRNA in obese insulin resistant (P=0.0034), but not insulin-sensitive subjects, while no correlations of ADIPOR2 with FOXO1 mRNA were noted. FOXO1 enhanced transcription from the ADIPOR1, but not the ADIPOR2 promoter in HepG2 cells., Conclusion: Increased hepatic ADIPOR1 and ADIPOR2 mRNA in insulin-resistant obese subjects may, at least in part, reflect a compensatory mechanism for reduced plasma adiponectin. FOXO1 may contribute to enhanced ADIPOR1, but not ADIPOR2 transcription in IR.
- Published
- 2010
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32. The SREBF-1 locus is associated with type 2 diabetes and plasma adiponectin levels in a middle-aged Austrian population.
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Felder TK, Oberkofler H, Weitgasser R, Mackevics V, Krempler F, Paulweber B, and Patsch W
- Subjects
- Aged, Austria epidemiology, Body Mass Index, Case-Control Studies, Diabetes Mellitus, Type 2 metabolism, Female, Genetic Predisposition to Disease epidemiology, Genetic Variation, Genotype, Humans, Insulin Resistance, Male, Middle Aged, Prevalence, Risk Factors, Sterol Regulatory Element Binding Protein 1 metabolism, Adiponectin blood, Diabetes Mellitus, Type 2 epidemiology, Diabetes Mellitus, Type 2 genetics, Polymorphism, Single Nucleotide, Sterol Regulatory Element Binding Protein 1 genetics
- Abstract
Context: The sterol regulatory element-binding protein-1c (SREBP-1c) is a transcription factor involved in the regulation of lipid and glucose metabolism and has been implicated in the pathophysiology of type 2 diabetes mellitus (T2DM)., Objective: We aimed to confirm associations of the SREBF-1 gene with T2DM in an Austrian population and to study possible associations with diabetes-related quantitative traits., Design, Settings and Participants: We genotyped a diabetic cohort (n=446) along with a control group (n=1524) for a common C/G variation that is located in exon 18c (rs2297508) and has been associated with obesity and T2DM in French populations., Main Outcome Measures: Body mass index (BMI), indices of insulin sensitivity and beta-cell function, plasma adiponectin, T2DM and single-nucleotide polymorphism rs2297508., Results: Genotype distributions associated with rs2297508 differed by T2DM status (P=0.0045), but not by BMI. The variant G allele was associated with a modest, but significant, increase in the prevalence of T2DM after adjustment for age, sex and BMI (G/G: odds ratios (OR) (95% confidence intervals)=1.45 (0.99-2.11) and G/C: OR=1.37 (1.04-1.81)). In a cross-sectional population of non-diabetic subjects, associations of rs2297508 genotypes with plasma adiponectin levels adjusted for age, sex and BMI (P=0.0017) were observed in that the risk G/G genotype displayed the lowest adiponectin levels., Conclusions: We observed associations of rs2297508 with T2DM prevalence and plasma adiponectin. SREBP-1c has been implicated in the regulation of adiponectin gene expression. Our results therefore raise the possibility that sequence variations at the SREBF-1 gene locus might contribute to T2DM risk, at least in part, by altering circulating adiponectin levels.
- Published
- 2007
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33. Role of peroxisome proliferator-activated receptor-gamma coactivator-1alpha in the transcriptional regulation of the human uncoupling protein 2 gene in INS-1E cells.
- Author
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Oberkofler H, Klein K, Felder TK, Krempler F, and Patsch W
- Subjects
- Animals, Cell Line, Tumor, Gene Expression Regulation physiology, Humans, Insulin Secretion, Insulin-Secreting Cells cytology, Ion Channels, Membrane Transport Proteins metabolism, Mitochondrial Proteins metabolism, Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha, Rats, Species Specificity, Transcriptional Activation genetics, Transcriptional Activation physiology, Triiodothyronine metabolism, Uncoupling Protein 2, Heat-Shock Proteins physiology, Insulin metabolism, Insulin-Secreting Cells metabolism, Membrane Transport Proteins genetics, Mitochondrial Proteins genetics, Promoter Regions, Genetic genetics, Regulatory Sequences, Nucleic Acid genetics, Transcription Factors physiology
- Abstract
A role of uncoupling protein 2 (UCP2) as negative modulator of insulin secretion has been suggested, but the transcriptional pathways regulating beta-cell UCP2 gene expression have been established in rodents only. We show here that the underlying sequence motifs are not conserved in the human gene and provide evidence for regulatory mechanisms involving the transcriptional cofactor peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1alpha). PGC-1alpha potentiates thyroid hormone (T(3))-mediated transcriptional activation of the human UCP2 gene in INS-1E cells. Two thyroid hormone response elements (TREs) located at -322/-317 (TRE1) and -170/-165 (TRE2) were identified, and mutation of either TRE1 or TRE2 abrogated the stimulatory effect of T(3) treatment. Furthermore, two E-box motifs at -911/-906 (E1) and -743/-738 (E2) are involved in the regulation of UCP2 gene expression by sterol regulatory element binding protein isoforms (SREBP)-1a, -1c, and -2. Mutational analysis revealed that the presence of either E1 or E2 is sufficient to mediate activation of UCP2 gene transcription by nuclear active SREBPs. PGC-1alpha coactivates liver X receptor-mediated expression of SREBP-1c as well as dexamethasone-stimulated SREBP-2 expression in INS-1E cells. These transcriptional responses are antagonized by orphan nuclear receptor short heterodimer partner overexpression, which might explain its positive effects on glucose-stimulated insulin secretion in beta-cells overexpressing UCP2. We also provide evidence that despite a lack of sequence homology within the regulatory region, the principal mechanisms regulating UCP2 gene expression are similar in rats and humans, being consistent with a role for UCP2 as a modulator of insulin secretion in humans.
- Published
- 2006
- Full Text
- View/download PDF
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