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Biomedical subjects

R J Wanders

Publications and source records attributed to R J Wanders.

At least 379 records · Page 21Linked to original sources

3-Hydroxydicarboxylic aciduria due to long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency associated with sudden neonatal death: protective effect of medium-chain triglyceride treatment.

Two siblings were found to be affected by long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency, one of which died suddenly and unexpectedly on the 3rd day of life suffering from extreme hypoketotic hypoglycaemia. The younger sibling started to have feeding problems, lowered consciousness, and liver dysfunction at the age of 5 months. Her urine contained large amounts of C6-C14 3-hydroxydicarboxylic acids and conjugated 3-hydroxyoctanoic acid, as verified by gas chromatography/mass spectrometry. Plasma long-chain acylcarnitine was increased. A clue to the diagnosis was given by the results of a phenylpropionic acid loading test. This revealed small, but significant amounts of conjugated 3-hydroxyphenylpropionic acid (phenylhydracrylic acid) in the patient's urine. Subsequently, the activity of long-chain 3-hydroxyacyl-CoA dehydrogenase was found to be deficient in cultured skin fibroblasts. Based on the findings obtained by a medium-chain triglyceride load, a diet enriched in this type of fat was prescribed. On this regimen the patient started to thrive, signs of cardiomyopathy disappeared, and her liver function normalized.

3-Hydroxyacyl CoA Dehydrogenases↗

Peroxisomal fatty acid beta-oxidation in relation to adrenoleukodystrophy.

X-linked adrenoleukodystrophy is a neurological disease characterized by progressive demyelination with destruction of the white matter, and adrenal insufficiency. Biochemically there is accumulation of very-long-chain fatty acids resulting from an impairment in the peroxisomal oxidation of these fatty acids. In this paper we describe the present state of our knowledge with regard to the organization of the peroxisomal fatty acid oxidation system, with particular emphasis on X-linked adrenoleukodystrophy.

Adrenoleukodystrophy↗

Identification of pristanoyl-CoA oxidase activity in human liver and its deficiency in the Zellweger syndrome.

The ability of human liver to oxidize pristanic acid was investigated. Liver from control subjects was found to contain pristanic acid oxidase activity, an H2O2-producing enzyme activity not previously demonstrated in mammals. In livers from patients with the cerebro-hepato-renal syndrome of Zellweger, a genetic disease characterized by the absence of morphologically distinguishable peroxisomes, pristanic acid oxidase activity was found to be deficient. These results indicate that pristanic acid is oxidized in peroxisomes rather than in mitochondria as believed until now. Furthermore, our findings provide an explanation for the elevated levels of pristanic acid in body fluids from patients lacking peroxisomes.

Acyltransferases↗

Rapid diagnosis of 3-hydroxy-3-methylglutaryl-coenzyme A lyase deficiency via enzyme activity measurements in leukocytes or platelets using a simple spectrophotometric method.

Patients with 3-hydroxy-3-methylglutaric aciduria due to a deficiency of 3-hydroxy-3-methylglutaryl Coenzyme A lyase usually present with a life-threatening crisis of hypoglycemia, metabolic acidosis and hyperammonemia. Diagnosis of this inborn error of leucine degradation is usually based upon gas-chromatographic analysis of organic acids in a patient's urine. In this paper we describe a simple spectrophotometric method allowing the activity of HMG-CoA lyase to be measured in leukocytes or platelets within a few hours, thus contributing to a rapid, unequivocal diagnosis and subsequent treatment. The validity of the method was established by demonstrating a deficient activity of HMG-CoA lyase in two patients with 3-hydroxy-3-methylglutaric aciduria. Furthermore, using this method, heterozygote detection can be done with great reliability.

Blood Platelets↗

Latency of the peroxisomal enzyme acyl-CoA:dihydroxyacetonephosphate acyltransferase in digitonin-permeabilized fibroblasts: the effect of ATP and ATPase inhibitors.

We have studied the activity of acyl-CoA:dihydroxyacetonephosphate acyltransferase (DHAP-AT) in fibroblasts treated with low concentrations of digitonin so that the cytoplasmic compartment was freely accessible to the substrates of DHAP-AT while intracellular membranes remained intact. DHAP-AT activity exhibited 70% latency under these conditions. This latency could be overcome by addition of ATP, resulting in a four-fold stimulation of DHAP-AT activity. Virtually no stimulatory effect of ATP on DHAP-AT activity was observed in sonicated fibroblasts or when a non-hydrolyzable ATP analogue was used. Furthermore the stimulatory effect of ATP was prevented in part by DCCD. N-ethylmaleimide and high concentrations of oligomycin; bafilomycin had no effect. This pattern of inhibitor sensitivity is similar to that of the ATPase activity in peroxisomal fractions from rat liver. We conclude that peroxisomes in situ exhibit structure linked latency and that ATP is required for the transport of at least one of the substrates of DHAP-AT.

Acyltransferases↗

Human liver L-alanine-glyoxylate aminotransferase: characteristics and activity in controls and hyperoxaluria type I patients using a simple spectrophotometric method.

We have studied the characteristics of human liver alanine-glyoxylate aminotransferase, which is deficient in hyperoxaluria type I, an inherited disorder of glyoxylate metabolism. The enzyme was optimally active at pH 8.0 showing apparent Km values for L-alanine and glyoxylate of 8.3 and 1.3 mmol/l, respectively. Activity was found to proceed linearly for up to 4 h. Measurements under these optimal conditions enabled the biochemical diagnosis of hyperoxaluria type I to be made via enzyme activity measurements in percutaneous needle biopsy specimens of liver tissue.

Alanine↗

Properties of the ATPase activity associated with peroxisome-enriched fractions from rat liver: comparison with mitochondrial F1F0-ATPase.

Highly purified peroxisomal fractions from rat liver contain ATPase activity (18.8 +/- 0.1 nmol/min per mg, n = 6). This activity is about 2% of that found in purified mitochondrial fractions. Measurement of marker enzyme activities and immunoblotting of the peroxisomal fraction with an antiserum raised against the beta-subunit of mitochondrial ATPase indicates that the ATPase activity in the peroxisomal fractions can not be ascribed to contamination with mitochondria or other subcellular organelles. From the sensitivity of the ATPase present in the peroxisomal fraction towards a variety of ATPase inhibitors, we conclude that it displays both V-type and F-type features and is distinguishable from both the mitochondrial F1F0-ATPase and the lysosomal V-type ATPase.

Adenosine Triphosphatases↗

Linkage of DNA markers at Xq28 to adrenoleukodystrophy and adrenomyeloneuropathy present within the same family.

We present a large kindred that contained patients with either adrenoleukodystrophy (ALD) or adrenomyeloneuropathy (AMN). The pedigree clearly supported the X-linked mode of inheritance of the nonneonatal form of ALD/AMN. Analysis with DNA markers at Xq28 suggested segregation of both ALD and AMN with an identical haplotype. This indicated that nonneonatal ALD and AMN are caused by a mutation in the same gene at Xq28. It showed, furthermore, that phenotypic differences between ALD and AMN are not necessarily the consequence of allelic heterogeneity due to different mutations within the same gene. The maximal lod score for linkage of the ALD/AMN gene and the multiallelic anonymous DNA marker at DXS52 was 3.0 at a recombination fraction of 0.00. This made a prenatal or presymptomatic diagnosis and heterozygote detection by DNA analysis with this marker reliable.

Adrenoleukodystrophy↗