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S Rost

Publications and source records attributed to S Rost.

At least 19 recordsLinked to original sources
PubMed2001

Seismic detection of rigid zones at the top of the core.

Data from earthquakes in the Tonga-Fiji region recorded at a seismic array in northern Australia show evidence for rigid zones at the top of the outer core. The ScP waveforms can be modeled by thin (0.12 to 0.18 kilometer) zones of molten iron mixed with solid material with a small, but positive, S-wave velocity (0.6 to 0.8 kilometer per second) that enables the propagation of S-waves in the outermost core. The zones may be topographic highs of the core-mantle boundary filled by light core sediments and might be important for variation of Earth's nutation and for convection of the outer core.

Journal Article↗
PubMed2001

Evaluation of DHPLC in the analysis of hemophilia A.

The manifestation of hemophilia A, a common hereditary bleeding disorder in humans, is caused by abnormalities in the factor VIII (FVIII) gene. A wide range of different mutations has been identified and provides the genetic basis for the extensive variability observed in the clinical phenotype. The knowledge of a specific mutation is of great interest as this may facilitate genetic counseling and prediction of the risk of anti-FVIII antibody development, the most serious complication in hemophilia A treatment to date. Due to its considerable size (7.2 kb of the coding sequence, represented by 26 exons), mutation detection in this gene represents a challenge that is only partially met by conventional screening methods such as denaturing gradient gel electrophoresis (DGGE) or single stranded conformational polymorphism (SSCP). These techniques are time consuming, require specific expertise and are limited to detection rates of 70-85%. In contrast, the recently introduced denaturing high performance liquid chromatography (dHPLC) offers a promising new method for a fast and sensitive analysis of PCR-amplified DNA fragments. To test the applicability of dHPLC in the molecular diagnosis of hemophilia A, we first assessed a cohort of 156 patients with previously identified mutations in the FVIII gene. Applying empirically determined exon-specific melting profiles, a total of 150 mutations (96.2%) were readily detected. Five mutations (3.2%) could be identified after temperatures were optimized for the specific nucleotide change. One mutation (0.6%) failed to produce a detectable heteroduplex signal. In a second series, we analyzed 27 hemophiliacs in whom the mutation was not identified after extensive DGGE and chemical mismatch cleavage (CMC) analysis. In 19 of these patients (70.4%), dHPLC facilitated the detection of the disease-associated nucleotide alterations. From these findings we conclude that the dHPLC technology is a highly sensitive method well suited to the molecular analysis of hemophilia A.

Base Sequence↗
PubMed2001

Lithuanian haemophilia A and B registry comprising phenotypic and genotypic data.

Haemophilia represents the most common hereditary severe bleeding disorder in humans. About 100 families with this condition live in Lithuania, one of the Baltic states with a population of 3.7 million. Haemophilia care and genetic counselling are still rendered difficult owing to limited availability of clotting factor concentrate and molecular genetic diagnosis. In the present study, a haemophilia registry, comprising phenotypic and genotypic data of the majority of Lithuanian haemophilia A and B patients, was established. The phenotype includes the degree of severity, factor VIII:C, factor VIII:Ag, factor IX:C, von Willebrand factor and antigen (VWF:RiCoF, vWF:Ag) and inhibitor status. Genotyping of the factor VIII and IX genes was performed using mutation screening methods and direct sequencing. In 61 out of 63 patients with haemophilia A (96.8%) and all eight patients with haemophilia B (100%), the causative mutations could be detected. Nineteen of the factor VIII gene defects and two of the factor IX gene mutations are reported for the first time. Identified mutations allowed direct carrier diagnosis in 83 female relatives revealing 44 carriers, 38 non-carriers and one somatic mosaicism. The information provided by this registry will be helpful for monitoring the treatment of Lithuanian haemophilia patients and also for reliable genetic counselling of the affected families in the future.

Factor IX↗
PubMed2000

De novo factor VIII gene intron 22 inversion in a female carrier presents as a somatic mosaicism.

The intron 22 inversion represents the most prevalent factor VIII gene defect in severe hemophilia A, accounting for about 40% of all mutations. It is hypothesized that the inversion mutations occur almost exclusively in germ cells during meiotic cell division by intrachromosomal recombination between 1 of 2 telomeric copies of the Int22h region and its intragenic homologue. The majority of inversion mutations originate in male germ cells, where the lack of bivalent formation may facilitate flipping of the telomeric end of the single X chromosome. This is the first intron 22 inversion that presents as a somatic mosaicism in a female, affecting only about 50% of lymphocyte and fibroblast cells of the proposita. Supposing a post-zygotic de novo mutation as the usual cause of somatic mosaicism, the finding would imply that the intron 22 inversion mutation is not restricted to meiotic cell divisions but can also occur during mitotic cell divisions, either in germ cell precursors or in somatic cells. (Blood. 2000;96:2905-2906)

Adult↗
PubMed2000

High CA repeat numbers in intron 13 of the endothelial nitric oxide synthase gene and increased risk of coronary artery disease.

Endothelial nitric oxide synthase (eNOS) plays a key role in vascular homeostasis. Because its product, nitric oxide, possesses vasodilatory and antiatherogenic properties, an altered eNOS function might promote atherosclerosis. We investigated the association between variations in CA repeat copy number [(CA), polymorphism] in intron 13 of the eNOS gene and the risk of coronary artery disease. (CA), polymorphism was investigated in 1000 consecutive patients with angiographically confirmed coronary artery disease and 1000 age- and gender-matched control subjects by a PCR-based fragment length calculation. Twenty-eight different alleles were identified containing 17-44 CA repeats. The presence of one allele containing > or = 38 repeats was associated with an excess risk of coronary artery disease (odds ratio 1.94, 95% confidence interval 1.31-2.86, P = 0.001). Carriers of alleles containing > or = 38 CA repeats were, in particular, overrepresented in the subgroup without common cardiovascular risk factors (odds ratio 3.39, 95% confidence interval 1.30-8.86, P = 0.009). Logistic regression analysis revealed that the (CA), polymorphism proved to be an independent risk factor (relative risk 2.17, 95% confidence interval 1.44-3.27, P = 0.0002). Our findings indicate that high numbers of CA repeats in intron 13 of the eNOS gene are associated with an excess risk of coronary artery disease.

Adenine↗
PubMed2000

Congenital deficiency of vitamin K dependent coagulation factors in two families presents as a genetic defect of the vitamin K-epoxide-reductase-complex.

Hereditary combined deficiency of the vitamin K dependent coagulation factors is a rare bleeding disorder. To date, only eleven families have been reported in the literature. The phenotype varies considerably with respect to bleeding tendency, response to vitamin K substitution and the presence of skeletal abnormalities, suggesting genetic heterogeneity. In only two of the reported families the cause of the disease has been elucidated as either a defect in the gamma-carboxylase enzyme (1) or in a protein of the vitamin K 2,3-epoxide reductase (VKOR) complex (2). Here we present a detailed phenotypic description of two new families with an autosomal recessive deficiency of all vitamin K dependent coagulation factors. In both families offspring had experienced severe or even fatal perinatal intracerebral haemorrhage. The affected children exhibit a mild deficiency of the vitamin K dependent coagulation factors that could be completely corrected by oral substitution of vitamin K. Sequencing and haplotype analysis excluded a defect within the gamma-carboxylase gene. The finding of highly increased amounts of vitamin K epoxide in all affected members of both families indicated a defect in a protein of the VKOR-multienzyme-complex. Further genetic analysis of such families will provide the basis for a more detailed understanding of the structure-function relation of the enzymes involved in vitamin K metabolism.

Blood Coagulation Factors↗
PubMed1998

Extracellular ATP causes apoptosis and necrosis of cultured mesangial cells via P2Z/P2X7 receptors.

Mesangial cells undergo cell death both by apoptosis and necrosis during glomerular disease. Since nucleotides are released from injured and destroyed cells in the glomerulus, we examined whether extracellular ATP and its receptors may regulate cell death of cultured mesangial cells. Addition of extracellular ATP (300 microM to 5 mM) to cultured rat mesangial cells for 90 min caused a 5. 8-fold increase in DNA fragmentation (terminal deoxynucleotidyl transferase assay) and a 4.2-fold increase in protein levels of the tumor suppressor p53, which is thought to regulate apoptosis. Apoptotic DNA fragmentation was confirmed by the diphenylamine assay and by staining with the DNA-specific fluorochrome Hoechst 33258. The necrotic markers, release of lactate dehydrogenase and uptake of trypan blue, were not positive before 3 h of ATP addition. The effects of ATP on DNA fragmentation and p53 expression were reproduced by the purinergic P2Z/P2X7 receptor agonist, 3'-O-(4-benzoylbenzoyl)-ATP, and inhibited by the P2Z/P2X7 receptor blocker, oxidized ATP. Transcripts encoding the P2Z/P2X7 receptor were expressed by cultured mesangial cells as determined by Northern blot analysis. P2Z/P2X7 receptor-associated pore formation in the plasma membrane was demonstrated by the Lucifer yellow assay. We conclude that activation of P2Z/P2X7 receptors by extracellular ATP causes apoptosis and necrosis of cultured mesangial cells. Activation of purinergic P2Z/P2X7 receptors may play a role in causing death of mesangial cells during glomerular disease.

Adenosine Triphosphate↗
PubMed1996

The chloroplast envelope is permeable for maltose but not for maltodextrins.

Permeation of [14 C]maltose into the stroma (measured as the sorbitol-impermeable space) of isolated intact spinach (Spinacia oleracea L.) chloroplasts was studied using the silicone oil centrifugation technique. Maltose uptake showed Michaelis Menten-kinetics with a K(m) of 25 mM and a Vmax of 19.5 mumol maltose. mg Chl-1. h-1 at 15 degrees C. Lack of interaction of glucose and maltose uptake suggested the presence of individual translocators for maltose and glucose in the inner chloroplast envelope. Maltose uptake was markedly inhibited by maltodextrins (maltotriose up to maltoheptaose). The corresponding [14C]maltodextrins were prepared by degradation of [14C]starch with pullulanase and alpha-amylase and purified by high performance TLC. None of these maltodextrins, when administered at a concentration of 10 mM, was transported into the sorbitol-impermeable space of the chloroplasts. The results suggest that the transport system for maltose is also accessible to maltodextrins but that only maltose can be translocated across the inner envelope of spinach chloroplasts.

Cell Membrane Permeability↗
PubMed1976

[Rehabilitation].

Explore the source record for details and available documents.

Persons with Disabilities↗
PubMed1976

[Industrial therapy 1975 (author's transl)].

The transition to industrial therapy following a preparatory period in a handicraft work therapeutic unit constitutes for the patients a decisive step from rehabilitation in a hospital to other rehabilitation facilities. Described are work principles, time of practice, payment, projects, social protection of labour, patients, working time, transitional period, assessment, theoretical instruction and work under real working conditions.

Persons with Disabilities↗