Biomedical subjects

A Navrátilová

Publications and source records attributed to A Navrátilová.

16 recordsLinked to original sources

PubMed2005

Long-range organization of plant satellite repeats investigated using strand-specific FISH.

The technique of chromosomal orientation and direction fluorescence in situ hybridization (COD-FISH) was adapted for plant chromosomes in order to study long-range organization of two families of satellite repeats, VicTR-B of Vicia sativa and PisTR-B of Pisum sativum. The technique allowed FISH to be performed on mitotic chromosomes in a strand-specific manner, resulting in visualization of the repeat orientation along the chromosomes and with respect to the direction of telomeric repeats. The VicTR-B probe applied to V. sativa chromosomes produced signals on a single chromatid at most regions containing corresponding sequences, thus confirming a presence of long arrays of head-to-tail arranged repeat monomers which is typical for satellite DNA. However, hybridization signals of different or equal intensities on both chromatids were also detected at some loci, suggesting a more complex arrangement of the repeats. Similar observations were made for PisTR-B repeats on P. sativum chromosomes, although the proportion of loci displaying signals on both chromatids was lower. In contrast to VicTR-B, orientation of the PisTR-B clusters with respect to telomeric sequences appeared to be conserved among subtelomeric regions of metacentric chromosomes and of the short arms of acrocentric chromosomes.

Base Sequence↗

PubMed2001

Microarray-based survey of repetitive genomic sequences in Vicia spp.

A modified DNA microarray-based technique was devised for preliminary screening of short fragment genomic DNA libraries from three Vicia species (V. melanops, V. narbonensis, and V. sativa) to isolate representative highly abundant DNA sequences that show different distribution patterns among related legume species. The microarrays were sequentially hybridized with labeled genomic DNAs of thirteen Vicia and seven other Fabaceae species and scored for hybridization signals of individual clones. The clones were then assigned to one of the following groups characterized by hybridization to: (1) all tested species, (2) most of the Vicia and Pisum species, (3) only a few Vicia species, and (4) preferentially a single Vicia species. Several clones from each group, 65 in total, were sequenced. All Group I clones were identified as rDNA genes or fragments of chloroplast genome, whereas the majority of Group II clones showed significant homologies to retroelement sequences. Clones in Groups III and IV contained novel dispersed repeats with copy numbers 10(2)-10(6)/1C and two genus-specific tandem repeats. One of these belongs to the VicTR-B repeat family, and the other clone (S12) contains an amplified portion of the rDNA intergenic spacer. In situ hybridization using V. sativa metaphase chromosomes revealed the presence of the S12 sequences not only within rDNA genes, but also at several additional loci. The newly identified repeats, as well as the retroelement-like sequences, were characterized with respect to their abundance within individual genomes. Correlations between the repeat distributions and the current taxonomic classification of these species are discussed.

Blotting, Southern↗

PubMed2000

Two new families of tandem repeats isolated from genus Vicia using genomic self-priming PCR.

A modified genomic self-priming technique was used for rapid isolation of tandem repeats from several Vicia species. Based on homologies of their nucleotide sequences the newly isolated clones were assigned to two repeat families named VicTR-A and VicTR-B. Both families are rich in AT (74%) and are organized as long blocks of tandemly repeated units. The VicTR-A repeats are characterized by a monomer size of 69 bp, whereas the VicTR-B repeat monomer is about 38 bp long, and the two families do not share significant sequence homology. VicTR sequences show different degrees of amplification (up to 10(6)-10(7) copies/haploid genome) in individual Vicia species and are not amplified in other legumes. The abundances of these repeats do not correlate with genome sizes but are similar in species that belong to the same taxonomic section within the genus Vicia. Primed in situ (PRINS) labeling of metaphase chromosomes of V. pannonica revealed that VicTR-A sequences are located predominantly in the telomeric regions of the short arms of all chromosomes. In contrast, labeling of VicTR-B repeats in V. sativa resulted in mainly intercalary bands of various intensities and only weak telomeric signals.

Base Composition↗

PubMed1990

[Our surgical approach in the treatment of otosclerosis over the past 10 years].

The most frequently used technique of surgery of otosclerosis used during the past ten years in the Central Military Hospital was Schuknecht's technique of wire and fat. 575 thus operated patients account for 89.4% of the total number of 643 operations. A compensation of the bone reserve to 0-10 dB was achieved in the late results of 56.3% of the operated patients, in another 30% there were auditory gains of speech frequencies, on average above 10 dB. Favourable late results were thus achieved in 86.3% of the operated patients, deterioration of hearing was recorded in 4.8% (13 operated patients). Pistons of Schuknecht's type were used in 23 patients with the obliterating form of otosclerosis. As to late results, in 21 of the evaluated patients compensation of the bone reserve to 0-10 dB was recorded in 28.6%. The mean auditory gains as regards speech frequencies higher than 10 dB were achieved in 47.6%. Favourable late results were thus recorded in 76.2% of operated patients with the obliterating form of otosclerosis. Deterioration of hearing occurred in this group in one operated patient (4.8%).

Humans↗

PubMed1989

[Revision after surgical procedures in the middle ear and mastoid].

In a group of 46 revised operations the most frequent cause of revision was persisting secretion--in 41 patients. After elimination of general causes and after failure of conservative treatment, during revision the following local causes were revealed: relapse of cholesteatoma in 44%, inflammation of the residual or repneumatized spaces in 41%, ostitis of the long process of the incus in 10% and inflammation in the divided trepanation cavities in 5%. By the first revision the authors achieved a dry trepanation cavity in 58.5% of the operated patients. By the second and third revision they increased the number of dry trepanation cavities to 83% and in the remaining ones there was only an occasional secretion. The revision involved usually a more radical procedure. In some of the patients operated by the "closed" technique the authors changed to the "open" technique. A radical approach to the auditory ossicles and the ear drum, if they were preserved during the primary operation, led to a deterioration of hearing in 22 of 41 operated patients, i. e. in 53.66%. This is the cost of obtaining a dry trepanation cavity.

Adolescent↗

PubMed1987