Biomedical subjects

S Kloska

Publications and source records attributed to S Kloska.

8 recordsLinked to original sources

PubMed2003

[Dose reduction of radiographs of the pediatric pelvis for diagnosing hip dysplasia using a digital flat-panel detector system].

PURPOSE: To evaluate a possible dose reduction in pediatric pelvic radiographs in congenital hip dysplasia using a digital flat-panel system instead of a phosphor-storage system. MATERIALS AND METHODS: During a six-month period, all pediatric patients referred for pelvic radiography for the evaluation of congenital hip dysplasia were randomly assigned to be examined by either a phosphor-storage system or a digital flat-panel system, whereby the latter system was operated with half the radiation dose. Thirty pairs of radiographs were assessed for the visibility of 16 anatomic details and for 5 orthopedic-radiographic measurements (5-point scale with 1 = excellent; three independent observers). The projection indices of Ball and Kommenda and of Tönnis and Brunken were calculated for all radiographs. The Student's t-test was used to compare the flat-panel and the phosphor-storage radiographs for observers' assessments, patients' age and projection indices. RESULTS: In a total of 7560 observations, the scores for the visibility of anatomic details and orthopedic-radiographic measurements were respectively 2.72 and 2.64 for the flat-panel system and 2.93 and 2.79 for the phosphor-storage system. No significant differences were found between both systems (p > 0.05) and between patient age and projection indices (p > 0.05). CONCLUSION: Pediatric pelvic radiographs can be obtained with a digital flat-panel system using half the radiation dose instead of a phosphor-storage system without sacrificing relevant information in the diagnosis of congenital hip dysplasia.

Age Factors↗

PubMed2002

[HIV-associated cerebral toxoplasmosis -- review and retrospective analysis of 36 patients].

Highly active antiretroviral therapy (HAART) has resulted in a reduction of morbidity and mortality in HIV-associated cerebral opportunistic infection. Before HAART, up to 50% of all HIV-infected patients in Europe developed cerebral toxoplasmosis, an encephalitis caused by reactivation of Toxoplasma gondii infection. Although potent therapeutical options exist, the prognosis is still poor. We describe the course of 36 AIDS patients with cerebral toxoplasmosis and present a review of clinical signs, diagnosis, therapy, and survival times. The main criteria for differential diagnosis from other secondary neuromanifestations such as primary CNS lymphoma, progressive multifocal leukencephalopathy, abscesses, and ischemic infarctions are described. Indications and problems of stereotactic biopsy are discussed.

AIDS-Related Opportunistic Infections↗

PubMed2001

Integrated studies on plant biology using multiparallel techniques.

Plant biology, especially the fields of molecular genetics and molecular physiology, is currently undergoing a change in paradigm from 'vertical' analysis of the role(s) of one or a few genes to 'horizontal' holistic approaches, studying the function of many or even all of the genes of an organism simultaneously. This change is leading us beyond genomes to transcriptomes, proteomes and metabalomes, and to an understanding of life at an entirely new level. Profiling strategies are putting this change into effect through the generation of large amounts of data, requiring that current bioinformatic approaches adapt and grow in order to make the most of these data.

Arabidopsis↗

PubMed2001

Response of Arabidopsis to iron deficiency stress as revealed by microarray analysis.

Gene expression in response to Fe deficiency was analyzed in Arabidopsis roots and shoots through the use of a cDNA collection representing at least 6,000 individual gene sequences. Arabidopsis seedlings were grown 1, 3, and 7 d in the absence of Fe, and gene expression in roots and shoots was investigated. Following confirmation of data and normalization methods, expression of several sequences encoding enzymes known to be affected by Fe deficiency was investigated by microarray analysis. Confirmation of literature reports, particularly for changes in enzyme activity, was not always possible, but changes in gene expression could be confirmed. An expression analysis of genes in glycolysis, the tricarboxylic acid cycle, and oxidative pentose phosphate pathway revealed an induction of several enzymes within 3 d of Fe-deficient growth, indicating an increase in respiration in response to Fe deficiency. In roots, transcription of sequences corresponding to enzymes of anaerobic respiration was also induced, whereas in shoots, the induction of several genes in gluconeogenesis, starch degradation, and phloem loading was observed. Thus, it seemed likely that the energy demand in roots required for the Fe deficiency response exceeded the capacity of oxidative phosphorylation, and an increase in carbon import and anaerobic respiration were required to maintain metabolism.

Adaptation, Physiological↗

PubMed1999

A complete BAC-based physical map of the Arabidopsis thaliana genome.

Arabidopsis thaliana is a small flowering plant that serves as the major model system in plant molecular genetics. The efforts of many scientists have produced genetic maps that provide extensive coverage of the genome (http://genome-www. stanford.edu/Arabidopsis/maps.html). Recently, detailed YAC, BAC, P1 and cosmid-based physical maps (that is, representations of genomic regions as sets of overlapping clones of corresponding libraries) have been established that extend over wide genomic areas ranging from several hundreds of kilobases to entire chromosomes. These maps provide an entry to gain deeper insight into the A. thaliana genome structure. A. thaliana has been chosen as the subject of the first large-scale project intended to determine the full genome sequence of a plant. This sequencing project, together with the increasing interest in map-based gene cloning, has highlighted the requirement for a complete and accurate physical map of this plant species. To supply the scientific community with a high-quality resource, we present here a complete physical map of A. thaliana using essentially the IGF BAC library. The map consists of 27 contigs that cover the entire genome, except for the presumptive centromeric regions, nucleolar organization regions (NOR) and telomeric areas. This is the first reported map of a complex organism based entirely on BAC clones and it represents the most homogeneous and complete physical map established to date for any plant genome. Furthermore, the analysis performed here serves as a model for an efficient physical mapping procedure using BAC clones that can be applied to other complex genomes.

Arabidopsis↗

PubMed1996

Transfer of rps19 to the nucleus involves the gain of an RNP-binding motif which may functionally replace RPS13 in Arabidopsis mitochondria.

The discovery of disrupted rps19 genes in Arabidopsis mitochondria prompted speculation about the transfer to the nuclear compartment. We here describe the functional gene transfer of rps19 into the nucleus of Arabidopsis. Molecular cloning and sequence analysis of rps19 show that the nuclear gene encodes a long N-terminal extension. Import studies of the precursor protein indicate that only a small part of this extension is cleaved off during import. The larger part of the extension, which shows high similarity to conserved RNA-binding domains of the RNP-CS type, became part of the S19 protein. In the Escherichia coli ribosome S19 forms an RNA-binding complex as heterodimer with S13. By using immuno-analysis and import studies we show that a eubacterial-like S13 protein is absent from Arabidopsis mitochondria, and is not substituted by either a chloroplastic or a cytosolic homologue of this ribosomal protein. We therefore propose that either a highly diverged or missing RPS13 has been functionally replaced by an RNP domain that most likely derived from a glycine-rich RNA-binding protein. These results represent the first case of a functional replacement of a ribosomal protein by a common RNA-binding domain and offer a new view on the flexibility of biological systems in using well-adapted functional domains for different jobs.

Amino Acid Sequence↗

PubMed1994

On the identification of group II introns in nucleotide sequence data.

Four different consensus sequences (GTI, group II identifiers) have been derived from domains V of known group II introns and are used as query input sequences for sensitive database screenings with the FASTA and LFASTA programs. The set of four GTI sequences can identify all domains V of the 96 known group II introns in the completely sequenced chloroplast genomes of Marchantia polymorpha, Epifagus virginiana, Oryza sativa, Nicotiana tabacum and the completely sequenced mitochondrial genomes of Saccharomyces cerevisiae, Podospora anserina, Schizosaccharomyces pombe and Marchantia polymorpha. Seven moderately high-scoring hits can easily be rejected as false-positives since they do not fulfil secondary structure requirements. Large FASTA outputs obtained after screening the entire nucleotide sequence database are evaluated in a second step by a program (D5SCAN) that allows the assignment of variable selection criteria for potential domain V secondary structures. Database searches with these routines yield evidence for several group II intron sequences previously unrecognized. These include novel intron structures in the cyanobacterium Synechocystis and in the mitochondrial genomes of Marchantia, soybean, pea, broad bean, sugar beet and a heterobasidiomycete. Potential intron remnants are found contributing to the secondary structure of rRNAs in several trypanosome species. At a given sensitivity of 95% positively identified true domains V, the search routine produces one false positive hit per 10,000 kb.

Amino Acid Sequence↗

PubMed1993

An adenine nucleotide translocator gene from Arabidopsis thaliana.

The sequence of an adenine nucleotide translocator (ANT) gene of Arabidopsis contains three introns, the first of which is located upstream of the assumed initiation codon. The presequence characteristic for plant ANTs is processed also in Arabidopsis as suggested by Western blot analysis, most likely at the conserved cleavage site.

Amino Acid Sequence↗