Search PubMed⌕ Search

Biomedical subjects

P Balícek

Publications and source records attributed to P Balícek.

At least 19 recordsLinked to original sources
PubMed2004

[Paracentric inversions of human chromosomes and their risks].

The incidence of paracentric inversions in the general population has not been clearly established, it ranges from 0.09 to 0.49/1,000. Homologue pairing during melosis in a paracentric-inversion heterozygote is maximized by the formation of an inversion loop. If a crossing-over occurs within this loop, dicentric and acentric chromosomes are formed. Resulting gametes can have variety of duplications and deficiencies and give a non-viable progeny. One of the exceptions to the rule is a mutation event "U loop recombination". From U-loop event a monocentric recombinant chromosome can arise by an abnormal process, which involves chromatid breakage and reunion. Most of the paracentric inversions in man are harmless and the risk of heterozygotes having a child with an unbalanced karyotype is relatively low. In carriers of an accidentally discovered paracentric inversion, amniocentesis is optional. However, in some cases, it is difficult to distinguish between a paracentric inversion and paracentric insertion--the risk of the insertion is about 15%. When a de novo inversion is detected in amniotic fluid, the overall risk for two-break rearrangements is 6.7%.

Chromosome Inversion↗
PubMed2004

[Case reports of patients with a marker chromosome].

Small, usually supernumerary chromosomes, denoted as marker chromosomes or markers, can be represented by various phenotypic expression, that depends on their origin and extent. Our article presents results of molecular cytogenetic analysis (FISH) of 34 patients with identified marker chromosome. In 21 cases a marker derived from acrocentric chromosome was identified, in 9 cases markers of gonosomal origin [der(X), der(Y)], and in 4 patients markers of some other chromosomes (5, 17, 18) were proved. The most frequent marker was that originating from chromosome 15 (8 cases). Two patients with different phenotype, markedly influenced by the extent of pseudoizodicentric chromosome 15 are described. In accordance with hitherto presented data, presence of supernumerary copies of the critical region PWACR (it is the partial trisomy, resp. tetrasomy 15q11-q13) in majority of cases brings about serious affection described as syndrome of the inverted duplication of chromosome 15. The most typical symptoms are psychomotoric retardation, hypotony, neurological symptoms and autistic features. The article stresses the importance of FISH method in the prenatal examination of marker chromosomes.

Adult↗
PubMed2002

Currarino triad: concurrent US and MRI diagnosis in the fetus and the mother.

We report an unusual case of the complete Currarino triad diagnosed in a fetus at 21 weeks' gestation by means of prenatal ultrasonography (US). The highly suspicious findings in the fetus were accompanied by analogous US findings in the mother who suffered from mild symptoms of up to that time unrecognized Currarino triad. Consecutively, magnetic resonance imaging (MRI) confirmed the findings simultaneously in the fetus and in her mother. This is the first report describing the prenatal diagnosis of Currarino triad without the background of positive family history. To our knowledge, the prenatal MRI findings of Currarino triad have not yet been published.

Abnormalities, Multiple↗
PubMed2001

[Prenatal diagnosis of de novo complex balanced rearrangements in chromosomes 3,4, and 13] ].

A case of apparently balanced de novo complex chromosome rearrangement with three breaks found in foetus by amniotic fluid examination is described. Amniocentesis was indicated because of low AFP in maternal serum during the first pregnancy of 25-year-old healthy woman. Her family anamnesis as well as her husbands on was insignificant, chromosomes were normal. Fetal karyotype was 46,XY,t(3;13;4)(q26.2;q21.3;q12). To eliminate further cryptic aberrations the multicolor FISH technique was employed. The risk of serious inborn malformation in complex rearrangement with three breaks was estimated on the basis of literary data to be 10.5% (3.5% per each break). The couple decided to terminate the pregnancy. No distinct anomaly was found in the fetus. Only 12 prenatal diagnoses of the complex balanced chromosome rearrangements formed de novo can be found in the literature. Total risk of the serious malformation relating to that small group of described cases is rather high. Only substantial enlargement of the clinic may enable to use prenatal evaluation of each individual case according to the number of chromosomal breaks or according to other criteria with more accurate results.

Abnormalities, Multiple↗
PubMed2001

[Pericentric inversion of human chromosomes and its risks] ].

Pericentric inversions of human chromosomes represent rearrangements are formed between two breaks on the short and on long arms of the chromosome with following rotation and new connection of the separated segment in the reversed position. The abnormality does not result in most of the carriers to any clinical manifestations. However, the basic risk the carriers of such inversion are exposed is the possibility of formation of a recombinant aneusomy--later transformation of the inverted chromosome during gametogenesis. Conception by the recombinant gamete usually results in spontaneous abortion or to a birth of seriously affected individual. The risk of recombination has to be in every newly registered inversion individually considered. The larger part of chromosome is taken into the pericentic inversion, the smaller is the extent of resulting duplication and smaller is the deficiency of chromosomal parts, which results from the recombination. The higher is then the viability of the affected foetus. In families with detected recombination, chromosomal examination is fully recommended. Prenatal examination is also indicated when the transformation is listed among the risk inversions or it has larger extent then recorded inversions. Beside the risk inversions, also the "safe" inversions exist, which include minor and frequently occurring transformation of chromosome No 2--inv(2)(p11q13) and inversion of chromosome 10--inv(10)(p11q21).

Chromosome Aberrations↗
PubMed1989

[Eosinophilic leukemia].

On the example of a patients with eosinophil leukaemia, which at first was manifested as eosinophilia in the peripheral blood stream and bone marrow without involvement of other organs and only after three years acquired the character of malignant growth, the authors draw attention to difficulties in the differential diagnosis of hypereosinophil syndrome. At the same time the authors review briefly views on the origin of eosinophil leukaemia, morphological and cytogenetic findings considered useful as evidence of this rare type of leukaemia.

Adult↗
PubMed1982

RHG-band polymorphism of the short arms of human acrocentric chromosomes and relationship of variants to satellite associations.

The extent of RHG-band variation of short arms of human acrocentric chromosomes was investigated in a group of 100 subjects by visually comparing the variants with the size of reference bands 7p22, 21q22 and 11q13. Marked differences were found among the chromosomes in the distribution of variants; the largest mean size of RHG-band was associated with chromosome 21, whereas the variants of chromosome 22 had the smallest band size. The study further showed that the involvement of acrocentric chromosomes in satellite association did not depend upon the size of RHG-band variants.

Chromosome Banding↗
PubMed1980

Intercalar satellites of human acrocentric chromosomes as a cytological manifestation of polymorphism in GC-rich material?

Fifteen unrelated individuals were found among the patients of the Cytogenetics Laboratory who possessed multiple-satellited marker chromosomes (14 with double satellites and 1 with triple satellites). Cytogenetic analysis was carried out by means of a conventional staining method and also by R, C, and Q banding and by the technique of silver staining. The intercalar structures of all 15 cases differed from the terminal satellites in their biochemical composition: they were resistant to heat denaturation, and stained heavily with the R-banding technique. Accordingly, they consisted of GC-rich material identical with that which in varying quantity is a regular constituent of the short arms of acrocentric chromosomes. The findings described indicate that any larger accumulation of such R band-positive material tends to dissociate from the basal segment of short arms by a proximal secondary constriction. We therefore assume that the formation of intercalar satellites may be interpreted as a cytological consequence of extreme natural R polymorphism.

Adult↗