Publications by authors named "Triepels R"

Purpose: To evaluate the performance of different probabilistic classifiers to predict posterior capsule rupture (PCR) prior to cataract surgery.

Methods: Three probabilistic classifiers were constructed to estimate the probability of PCR: a Bayesian network (BN), logistic regression (LR) model, and multi-layer perceptron (MLP) network. The classifiers were trained on a sample of 2 853 376 surgeries reported to the European Registry of Quality Outcomes for Cataract and Refractive Surgery (EUREQUO) between 2008 and 2018.

View Article and Find Full Text PDF

Background: The metabolic health index (MHI) is a biomarker-based model that objectively assesses the cumulative impact of comorbidities type 2 diabetes mellitus, hypertension and dyslipidemia on the health state of bariatric patients. The MHI was developed on a single-center cohort using a fully laboratory data-driven approach, resulting in a MHI score on a range from 1 to 6. To show universal applicability in clinical care, the MHI was validated externally and potential laboratory-related shortcomings were evaluated.

View Article and Find Full Text PDF

Because hyponatraemia can be caused by many disorders, the diagnostic approach to hyponatraemia can be challenging for physicians. Causes of hyponatraemia can be classified according to a combination of laboratory parameters (e.g.

View Article and Find Full Text PDF

Background: Pancreatitis-associated protein (PAP) is currently discussed as a marker in newborn screening (NBS) for cystic fibrosis (CF). However, it is not known if PAP concentrations are influenced by sex, gestational age, birth weight, blood transfusion or time of collection and what this would mean for NBS for CF.

Methods: In 2008 all newborns in part of the Netherlands were screened for CF by an IRT/PAP protocol.

View Article and Find Full Text PDF

Context: Newborn screening for cystic fibrosis (CF) is included in many routine programmes but current strategies have considerable drawbacks, such as false-positive tests, equivocal diagnosis and detection of carriers.

Objective: To assess the test performance of two newborn screening strategies for CF.

Design, Setting And Participants: In 2008 and 2009, CF screening was added to the routine screening programme as a prospective study in part of The Netherlands.

View Article and Find Full Text PDF

We describe a novel mutation in the ND6 gene (T14487C) in a patient with Leigh syndrome. Biochemical analyses indicated a low complex I activity in the patient's fibroblasts but normal values in muscle and liver. Cybrid clones showed a specific complex I defect that correlates with the mutant heteroplasmy levels.

View Article and Find Full Text PDF

Oxidative phosphorylation disorders make a contribution of 1 per 10,000 live births in man, of which isolated complex I deficiency is frequently the cause. Complex I, or NADH:ubiquinone oxidoreductase, is the largest multi-protein enzyme complex of the mitochondrial electron transfer chain. In complex I deficiency, various clinical phenotypes have been recognized, often resulting in multi-system disorders with a fatal outcome at a young age.

View Article and Find Full Text PDF

Complex I defects are one of the most frequent causes of mitochondrial respiratory chain disorders. Therefore, it is important to find new approaches for detecting and characterizing Complex I deficiencies. In this paper, we introduce a new set of monoclonal antibodies that react with 39-, 30-, 20-, 18-, 15-, and 8-kDa subunits of Complex I.

View Article and Find Full Text PDF

Deficiency of NADH:ubiquinone oxidoreductase, the first enzyme complex of the mitochondrial respiratory chain, is one of the most frequent causes of human mitochondrial encephalomyopathies. A relatively small percentage of human complex I deficiency is associated with mitochondrial DNA mutations. cDNA characterization and mutational analysis of the structural complex I genes in 19 complex I-deficient patients, in whom common mtDNA mutations have been excluded, has so far revealed five patients with alterations in evolutionary conserved nuclear-encoded proteins.

View Article and Find Full Text PDF

We retrospectively examined clinical and biochemical characteristics of 27 patients with isolated enzymatic complex I deficiency (established in cultured skin fibroblasts) in whom common pathogenic mtDNA point mutations and major rearrangements were absent. Clinical phenotypes present in this group are Leigh syndrome (n = 7), Leigh-like syndrome (n = 6), fatal infantile lactic acidosis (n = 3), neonatal cardiomyopathy with lactic acidosis (n = 3), macrocephaly with progressive leukodystrophy (n = 2), and a residual group of unspecified encephalomyopathy (n = 6) subdivided into progressive (n = 4) and stable (n = 2) variants. Isolated complex I deficiency is one of the most frequently observed disturbance of the OXPHOS system.

View Article and Find Full Text PDF

Leigh syndrome is the phenotypical expression of a genetically heterogeneous cluster of disorders, with pyruvate dehydrogenase complex deficiency and respiratory chain disorders as the main biochemical causes. We report the first missense mutation within the nuclear encoded complex I subunit, NDUFS7, in 2 siblings with neuropathologically proven complex I-deficient Leigh syndrome.

View Article and Find Full Text PDF

We present the cDNA sequence of the human mitochondrial acyl carrier protein NDUFAB1, a nuclear-encoded subunit of complex I of the mitochondrial respiratory chain. We obtained the NDUFAB1 cDNA using the cDNA sequence of the bovine mitochondrial acyl carrier protein. The human cDNA contains two putative translation initiation codons.

View Article and Find Full Text PDF

We have cloned the cDNA of the NDUFS5 subunit (15 kDa) of the human mitochondrial respiratory chain complex NADH: ubiquinone oxidoreductase (complex I). The open reading frame consists of 321 base-pairs, coding for 106 amino acids, with a calculated molecular mass of 12.5 kDa.

View Article and Find Full Text PDF

NADH:ubiquinone oxidoreductase (complex I) is an extremely complicated multiprotein complex located in the inner mitochondrial membrane. Its main function is the transport of electrons from NADH to ubiquinone, which is accompanied by translocation of protons from the mitochondrial matrix to the intermembrane space. Human complex I appears to consist of 41 subunits of which 34 are encoded by nDNA.

View Article and Find Full Text PDF

We report the cloning of the cDNA sequence of the nuclear-encoded NDUFA8 subunit of NADH: ubiquinone oxidoreductase, the first mitochondrial respiratory chain complex. The NDUFA8 open reading frame (ORF) includes 519 bp and encodes 172 amino acids (Mr=20.1 kDa).

View Article and Find Full Text PDF

Nicotinamide adenine dinucleotide (NADH):ubiquinone oxidoreductase (complex I) is the largest multiprotein enzyme complex of the respiratory chain. The nuclear-encoded NDUFS8 (TYKY) subunit of complex I is highly conserved among eukaryotes and prokaryotes and contains two 4Fe4S ferredoxin consensus patterns, which have long been thought to provide the binding site for the iron-sulfur cluster N-2. The NDUFS8 cDNA contains an open reading frame of 633 bp, coding for 210 amino acids.

View Article and Find Full Text PDF
Article Synopsis
  • Bovine NADH:ubiquinone oxidoreductase, a key enzyme in the mitochondrial respiratory chain, has around 36 subunits, with 15 of them identified in humans so far.
  • A new subunit, B17, has been discovered, with its cDNA sequence identified as 598-bp, showing high homology to the bovine version.
  • This B17 subunit is located on chromosome 2, is widely expressed in various tissues (especially in high-energy demanding ones like the kidney), and showed no mutations in a study of patients with complex I deficiency.
View Article and Find Full Text PDF

The mitochondrial electron transport chain (mtETC) consists of four multi-subunit enzyme complexes. Complex I or NADH:ubiquinone oxidoreductase, the largest mtETC multisubunit complex, consists of approximately 41 subunits. Seven of these subunits are encoded by the mitochondrial genome, the remainder by the nuclear genome.

View Article and Find Full Text PDF

NADH:ubiquinone oxidoreductase (complex I) of the mitochondrial respiratory chain can be fragmented in a flavoprotein (FP), iron-sulfur protein (IP), and hydrophobic protein (HP) subfraction. The IP subfraction is hypothesized to be significant, since it contains important prosthetic groups highly conserved among species. We cloned the cDNA of three remaining human NADH:ubiquinone oxidoreductase subunits of this IP fraction: the NDUFS2 (49 kDa), NDUFS3 (30 kDa), and NDUFS6 (13 kDa) subunits.

View Article and Find Full Text PDF