Quantitative acylcarnitine profiling in fibroblasts using [U-13C] palmitic acid: an improved tool for the diagnosis of fatty acid oxidation defects.

A method was developed for the investigation of mitochondrial fatty acid beta-oxidation in cultured fibroblasts. Monolayer cultures were incubated without foetal calf serum with commercially available [U-13C] palmitic acid and L-carnitine for 96 h. The acylcarnitines produced by the cells were extracted from the cell suspension and analysed either by quantitative stable isotope dilution gas chromatography chemical ionization mass spectrometry, or by fast atom bombardment mass spectrometry.

Lactic acidosis in long-chain fatty acid beta-oxidation disorders.

Among the many disorders of fatty acid beta-oxidation known today, the disorders of long-chain fatty acid oxidation are the most severe and life-threatening. One remarkable abnormality, not observed in, for instance, medium-chain acyl-CoA dehydrogenase deficiency, is the moderate to severe lactic acidaemia in long-chain fatty acid beta-oxidation-deficient patients, suggesting that oxidation of pyruvate is also compromised. In order to understand the underlying basis of the lactic acidaemia in these patients, we have studied the formation of L-lactate and pyruvate in cultured skin fibroblasts incubated with D-glucose.

2,6-Dimethylheptanoyl-CoA is a specific substrate for long-chain acyl-CoA dehydrogenase (LCAD): evidence for a major role of LCAD in branched-chain fatty acid oxidation.

Oxidation of straight-chain fatty acids in mitochondria involves the complicated interaction between a large variety of different enzymes. So far four different mitochondrial straight-chain acyl-CoA dehydrogenases have been identified. The physiological function of three of the four acyl-CoA dehydrogenases has been resolved in recent years especially from studies on patients suffering from certain inborn errors of mitochondrial fatty acid beta-oxidation.

Molecular basis of hepatic carnitine palmitoyltransferase I deficiency.

Mitochondrial fatty acid beta-oxidation is important for energy production, which is stressed by the different defects found in this pathway. Most of the enzyme deficiencies causing these defects are well characterized at both the protein and genomic levels. One exception is carnitine palmitoyltransferase I (CPT I) deficiency, of which until now no mutations have been reported although the defect is enzymatically well characterized.

Carnitine palmitoyltransferase II specificity towards beta-oxidation intermediates--evidence for a reverse carnitine cycle in mitochondria.

Using isolated rat liver mitochondria, in the absence or presence of malonyl-CoA (an inhibitor of carnitine palmitoyltransferase I), we have found that carnitine palmitoyltransferase II (CPT II) is active with palmitoyl-CoA as well as with its beta-oxidation intermediates. A partially purified CPT II fraction from rat liver mitochondria was shown to be able to convert 3-hydroxypalmitoyl-CoA to 3-hydroxypalmitoylcarnitine, which could be identified by fast-atom-bombardment mass spectrometry. This apparent broad specificity of CPT II was further evaluated by kinetic studies using purified CPT II.

Relatedness of matrilines, dispersing males and social groups in long-tailed macaques (Macaca fascicularis).

Genealogical relatedness is thought to be an important causal factor in the evolution of cooperation. We inferred relatedness on the basis of 11 blood protein markers using the Queller and Goodnight index of relatedness in a macaque population with long-term demographic records. This estimate reflected independently determined pedigree relationships in our data set.

Succinyl-CoA:acetoacetate transferase deficiency: identification of a new patient with a neonatal onset and review of the literature.

Unlabelled: We describe the clinical symptoms and biochemical findings of a patient with succinyl-CoA:acetoacetate transferase deficiency who presented in the neonatal period and review the current literature on this subject. Our patient was initially suspected to have distal renal tubular acidosis, and subsequently, a fasting test revealed severe metabolic ketoacidosis with normal blood glucose after 13 h which suggest a defect in ketolysis. In his cultured skin fibroblasts succinyl-CoA:acetoacetate transferase was deficient (residual activity 15%).

A single [3H]thymidine-based limiting dilution analysis to determine HTLp and CTLp frequencies for bone marrow donor selection.

Histocompatibility between recipient and donor is a critical factor in allogeneic BMT which, to a large extent, determines the incidence of GVHD after BMT. Functional histocompatibility assays, such as the helper T lymphocyte precursor frequency assay (HTLp) and the cytotoxic T lymphocyte precursor frequency assay (CTLp), have proved to be helpful tools in facilitating donor selection procedures. However, a major drawback of these assays is that they are laborious and require large numbers of cells.

Analysis of atrial sensed far-field ventricular signals: a reassessment.

Accurate detection of the spontaneous far-field ventricular signal may be used to determine the ventricular activation, and hence, the interval from atrial stimulus to the ventricular R wave (AR interval) using a standard atrial pacing lead. This can be useful in developing a physiological atrial rate responsive (AAIR) pacemaker and in further improving DDD(R) pacing algorithms. In order to better characterize the atrial sensed far-field ventricular signal, 200 consecutive patients undergoing pacemaker implantation were studied.

Common missense mutation G1528C in long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency. Characterization and expression of the mutant protein, mutation analysis on genomic DNA and chromosomal localization of the mitochondrial trifunctional protein alpha subunit gene.

Mitochondrial trifunctional protein (MTP) is a recently identified enzyme involved in mitochondrial beta-oxidation, harboring long-chain enoyl-CoA hydratase, long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and long-chain 3-ketothiolase activity. A deficiency of this protein is associated with impaired oxidation of long-chain fatty acids which can lead to sudden infant death. Furthermore, it is clear that this inborn error of fatty acid oxidation is very frequent, second to medium chain acyl-CoA dehydrogenase deficiency.

Inhibition of oxidative phosphorylation by palmitoyl-CoA in digitonin permeabilized fibroblasts: implications for long-chain fatty acid beta-oxidation disorders.

Long-chain fatty acid oxidation deficient patients present early in life with more severe features than patients with a medium-chain fatty acid oxidation deficiency. This may be related to the more toxic effect of long-chain fatty acid derivatives. In this paper we have studied the effect of different acyl-CoA esters, and palmitoyl-CoA in particular, on succinate-driven oxidative phosphorylation, using digitonin permeabilized human fibroblasts.

Measurement of peroxisomal fatty acid beta-oxidation in cultured human skin fibroblasts.

One of the main functions of mammalian peroxisomes is the beta-oxidation of a variety of fatty acids and fatty acid derivatives, including very long-chain fatty acids. Oxidation of these fatty acids is deficient in a number of different peroxisomal disorders, including the disorders of peroxisome biogenesis (Zellweger syndrome, neonatal adrenoleukodystrophy and infantile Refsum disease), X-linked adrenoleukodystrophy and a number of other disorders of peroxisomal beta-oxidation of known and unknown aetiology. Accurate measurement of peroxisomal fatty acid oxidation is of utmost importance for correct postnatal and prenatal diagnosis of these disorders.

Genetic structure of a population with social structure and migration.

Long-tailed macaques (Macaca fascicularis) live in social groups consisting of resident adult females and their offspring, and immigrant males. Subadult males leave their birth group, and might establish themselves as reproducing males in another group. Females do not leave their birth group.

Studies on mitochondrial oxidative phosphorylation in permeabilized human skin fibroblasts: application to mitochondrial encephalomyopathies.

In this report we describe that the functional capacity of the mitochondrial oxidative phosphorylation system can be studied in cultured skin fibroblasts permeabilized with a limited amount of digitonin. By using a variety of different oxidizable substrates, information can be obtained on the functional activity of complex I, for instance, which is important since different diseases in man have recently been identified in which complex I is deficient. The method described may contribute to the biochemical characterization of patients suffering from one of a variety of encephalomyopathies.

Cancer patients and their network: the meaning of the social network and social interactions for quality of life.

A lot of research is carried out on the subject of social relations and quality of life. One should find at least some indication for an association between the social environment and quality of life of cancer patients; will interventions be appropriate and well-considered? But until now, less has been known about the association between the social network of cancer patients and their quality of life. In this study, the way in which the patients' network can effect their quality of life is examined.

Differentiation and proliferation of respiration-deficient human myoblasts.

Replication and transcription of mitochondrial DNA were impaired in dividing human myoblasts exposed to ethidium bromide. MtDNA content decreased linearly per cell division and mitochondrial transcript levels declined rapidly, resulting in respiration-deficiency of the myoblasts. Despite the absence of functional mitochondria the cells remained able to proliferate when grown under specific culture conditions.