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H Houstková

Publications and source records attributed to H Houstková.

9 recordsLinked to original sources
PubMed2001

Pulmonary storage with emphysema as a sign of Niemann-Pick type C2 disease (second complementation group). Report of a case.

A case is described of Niemann-Pick type C2 disease presenting an infantile pneumopathic phenotype known to occur in this recently established, second, minor complementation group of Niemann-Pick type C (NPC) disease. However, the pulmonary involvement was unique, being dominated, in addition to the usual storage macrophage infiltration of the alveolar and septal compartments, by irregular emphysema attributed to storage cell migration into the bronchiolar lumen. The latter modified considerably the X-ray findings and hindered the initial clinical diagnosis. Otherwise, the storage phenotype, including the range of stored lipids, storage distribution, and cell and organ pathology, was found to be identical to that in the whole Niemann-Pick type C disease group dominated by NPC1. The biochemical findings (cholesterol esterification level) corresponded to the classical biochemical phenotype. Emphysema should thus be considered as a variant of the pulmonary NPC2 storage process, governed most probably by an epigenetic mechanism responsible for storage macrophage migration into the bronchiolar compartment.

Emphysema↗
PubMed1999

Defective kinetics of cytochrome c oxidase and alteration of mitochondrial membrane potential in fibroblasts and cytoplasmic hybrid cells with the mutation for myoclonus epilepsy with ragged-red fibres ('MERRF') at position 8344 nt.

We have investigated pathogenic effects of the tRNA(Lys) A8344G mutation associated with the syndrome myoclonus epilepsy with ragged-red fibres (MERRF) by using fibroblasts and fibroblast-derived cytoplasmic hybrid cells harbouring different percentages of mutated mitochondrial DNA (mtDNA). The activity of cytochrome c oxidase (COX) in patient fibroblasts with 89% mutated mtDNA was decreased to 20% of the control levels. COX exhibited altered kinetics, with a decreased V(max) for both the low-affinity and high-affinity phases; however, the K(m) values were not significantly changed. The substrate-dependent synthesis of ATP was decreased to 50% of the control. Analysis of the mitochondrial membrane potential, DeltaPsi, in digitonin-treated cells with tetramethylrhodamine methyl ester (TMRM) with the use of flow cytometry showed a 80% decrease in DeltaPsi at state 4 and an increased sensitivity of DeltaPsi to an uncoupler in fibroblasts from the patient. The investigation of transmitochondrial cytoplasmic hybrid clones derived from the patient's fibroblasts enabled us to characterize the relationship between heteroplasmy of the MERRF mutation, COX activity and DeltaPsi. Within the range of 87-73% mutated mtDNA, COX activity was decreased to 5-35% and DeltaPsi was decreased to 6-78%. These results demonstrate that the MERRF mutation affects COX activity and DeltaPsi in different proportions with regard to mutation heteroplasmy and indicate that the biochemical manifestation of the MERRF mutation exerts a very steep threshold of DeltaPsi inhibition.

Adenosine Triphosphate↗
PubMed1999

Complex approach to prenatal diagnosis of cytochrome c oxidase deficiencies.

Different severe disorders of cytochrome c oxidase (COX) have been described in children, but only the defects with autosomal inheritance are suitable for prenatal diagnosis. To perform prenatal diagnosis of fatal infantile COX deficiency a complex approach has been used which combined determination of the genetic origin of the defect, and detailed analysis of the function, content and subunit composition of the enzyme in cultured fetal cells. The tissues and cultured fibroblasts of the patient with Leigh's syndrome showed a COX deficiency of systemic character. The decrease of COX activity to 5-11 per cent was accompanied by proportionally decreased content of the assembled COX enzyme. With the help of transmitochondrial cybrids derived from patient fibroblasts it was proven that the COX defect was of nuclear origin. In a successive pregnancy, the function of oxidative phosphorylation (OXPHOS) was analysed in cultured amniocytes by substrate-stimulated ATP production and COX activity was compared with the activity of citrate synthase. The amount and composition of OXPHOS complexes was estimated by two-dimensional (Blue Native/SDS) polyacrylamide gel electrophoresis and was verified immunochemically with specific antibodies. Three independent lines of evidence provided us with reliable data on the function of COX and OXPHOS in fetal cells which were sufficient to rule out the expected enzymatic defect within three weeks after amniocentesis.

Adenosine Triphosphate↗
PubMed1997

[Enzyme therapy in children with severe forms of Gaucher's disease].

The enzyme therapy with Ceredase in patients with Gaucher's disease is at present probably the most expensive treatment in the whole world. One-year treatment of an adult patient with Gaucher's disease costs more than 7 million crowns. Indications for treatment in individual patients as well as financial provisions are so far problematic in the Czech Republic. From a total of 28 patients of varying age with Gaucher's disease diagnosed by the authors Ceredase was administered to two boys with a severe course of the disease. Within one year of treatment the health status of both children improved, growth became normal, the spleen diminished in size by 20-35%, haematological manifestations of hypersplenism are receding, there was a 32-46% decline of the activity of serum chitotriosidase and biochemical parameters of the disease improved.

Child↗
PubMed1995

Altered properties of mitochondrial ATP-synthase in patients with a T-->G mutation in the ATPase 6 (subunit a) gene at position 8993 of mtDNA.

A family is described with a T-->G mutation at position 8993 of mtDNA. This mutation is located in the ATPase 6 gene of mtDNA which encodes subunit a of the ATP-synthase complex (FlFo-ATPase). Clinically, the patients showed severe infantile lactate acidosis and encephalomyopathy in a form that was different from the classical Leigh syndrome. In 3 affected boys, ranging in age from 3 months to 8 years, the mutation was found in 95-99% of the mtDNA population. The clinical symptoms correlated with the mtDNA heteroplasmy and in the healthy mother 50% of the mtDNA was mutated. The rate of mitochondrial ATP production by cultured skin fibroblasts containing 99% of mutated mtDNA was about 2-fold lower than that in normal fibroblasts. Native electrophoresis of the mitochondrial enzyme complexes revealed instability of the FlFo-ATPase in all the tissues of the patient that were investigated (heart, muscle, kidney, liver). Only a small portion of the ATP-synthase complex was present in the complete, intact form (620 kDa). Incomplete forms of the enzyme were present as subcomplexes with approx. molecular weights of 460, 390 and 150 kDa, respectively, which differed in the content of F1 and Fo subunits. Immunochemical analysis of the subunits of the FlFo-ATPase further revealed a markedly decreased content of the Fo subunit b in mitochondria from muscle and heart, and an increased content of the Fo subunit c in muscle mitochondria, respectively. These results indicate that in this family the T-->G point mutation at position 8993 in the mitochondrial ATPase 6 gene is accompanied by structural instability and altered assembly of the enzyme complex, that are both most likely due to changes in the properties of subunit a of the membrane sector part of the ATP-synthase.

Acidosis, Lactic↗
PubMed1985

Resin hemoperfusion in hepatic porphyrias.

In three types of hepatic porphyrias, 32 hemoperfusions over polyhema-coated Amberlite XAD-2 resin were performed. An attack of acute intermittent porphyria subsided after a 6-h hemoperfusion. During the procedure, 13 L of plasma was completely cleared of porphyrins. In a child with variegate porphyria, the laboratory changes were slight and no clinical effect of hemoperfusion was seen. In a patient suffering from porphyria cutanea tarda resistant to standard therapy, 30 hemoperfusions were performed during a period of 10 months. The total plasma porphyrin concentration increased sharply following the start of the treatment, and preceding the fifth procedure it reached a peak of four times the initial value. Since then, the plasma porphyrin level decreased, eventually to one-half the starting value. The mean drop in porphyrin level during each perfusion was 22%. Similar changes were observed in the amount of porphyrins excreted into the urine, which, following an early rise, decreased to 25% of the initial value. However, the patient's skin vulnerability improved only slightly. There were no untoward effects of the treatment.

Adult↗
PubMed1983

[Isovaleric aciduria].

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Amino Acid Metabolism, Inborn Errors↗