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G Palka

Publications and source records attributed to G Palka.

At least 55 records · Page 3Linked to original sources
PubMed1997

Clustering of Y chromosome deletions in subinterval E of interval 6 supports the existence of an oligozoospermia critical region outside the DAZ gene.

Y chromosome molecular analysis was performed using the STS-PCR technique in 50 patients with oligozoospermia. Microdeletions of interval 6 of the Y chromosome were detected in seven patients, in six of whom subinterval E was affected. All patients retained the RBM1 and DAZ genes, while in one deletion involved the SPGY gene. The size of the deletion was not apparently related to the severity of the disease. These results suggest the presence of an oligozoospermia critical region on the Y chromosome within subinterval E of interval 6.

Adult↗
PubMed1997

Two newborns with chromosome 4 imbalances: deletion 4q33-->q35 and ring r(4)(pterq35.2-qter).

Two patients are reported who presented with 4q deletion and r(4), respectively. Cytogenetic and FISH analysis defined the breakpoints respectively at bands 4q33-->q35 proximal to the telomere, and 4pter and 4q35.2 qter. Moreover in both cases rearranged chromosomes maintained telomeric sequences. The first patient showed some clinical features of deletion 4q and a pointed 5th finger, a characteristic finding in deletion 4q31-->qter. The second patient had mild dysmorphism associated with growth retardation.

Chromosome Deletion↗
PubMed1996

Complex chromosome translocations of standard t(8;21) and t(15;17) arise from a two-step mechanism as evidenced by fluorescence in situ hybridization analysis.

The authors report the results of cytogenetic and fluorescence in situ hybridization (FISH) analysis performed on complex chromosome translocations (CCTs) of t(8;21) and t(15;17) standard translocations associated with two M2 subtypes of acute myeloid leukemia (AML-M2) and four acute promyelocytic leukemia (APL), respectively. In one of two AML-M2 patients FISH analysis showed part of chromosome 21 on the der(8) and material from this chromosome on the der(21) and on chromosome 1 at band p32, suggesting that the t(8;21) occurred as the primary step. In the second AML-M2 patient. FISH displayed part of chromosome 21 on the der(8) and material from this chromosome on the der(21) but not on the third rearranged chromosome. Therefore, it is unclear whether chromosome 2 was rearranged secondary to the standard t(8;21). In four APL patients, FISH analysis showed material derived from chromosome 17 on the der(15). Moreover, in two patients with an i(17q) FISH disclosed material from chromosome 15 at the ends of both arms of the i(17q), suggesting that it occurred after the standard t(15;17). In the remaining two APL patients, FISH showed material from chromosome 15 on the der(17) and on chromosome 21 at band q22 in one case, and material of the p arm of chromosome 17 on chromosome 4 at band q11 in the other, demonstrating that in these two cases the first mutation also had been the t(15;17). Therefore, FISH analysis revealed that CCTs in five patients were secondary changes which occurred after standard t(8;21) and t(15;17), thus clarifying the hierarchy of the cytogenetic events, their role in the pathogenesis of the disease, and the associated clinic-hematologic findings.

Adult↗
PubMed1996

Non-invasive early prenatal molecular diagnosis using retrieved transcervical trophoblast cells.

Fetal DNA was recovered from 17 of 39 (44%) transcervical cell (TCC) samples obtained between 7 and 9 weeks of gestation by endocervical canal flushing. Trophoblast retrieval was adequate for polymerase chain reaction (PCR) amplification of Y chromosome-specific DNA sequences and detection of paternal-specific microsatellite alleles. The fetal sex predicted by PCR in TCCs was confirmed in all cases by karyotype analysis of chorionic villi at 10 weeks of gestation. The absence of the disease-associated paternal alleles in TCC samples from two pregnancies at risk for spinal muscular atrophy and myotonic dystrophy predicted unaffected fetuses in agreement with subsequent results on chorionic villi and newborns' leukocytes. A trisomy 21 fetus was diagnosed in TCCs using fluorescent in situ hybridization (FISH) and semi-quantitative PCR analysis of superoxide dismutase-1 (SOD 1). Present experience indicates that TCC sampling is a promising technique for early prenatal monitoring of Mendelian disorders and chromosome aneuploidy.

Adult↗
PubMed1996

Diagnosis of DiGeorge syndrome in nuclei released from archival autoptic heart specimens using fluorescence in situ hybridization.

Seven formalin-fixed, paraffin-embedded heart specimens set up at autopsy performed from 3 to 18 years before analysis of newborns in which DiGeorge syndrome (DGS) was suspected were evaluated by fluorescence in situ hybridization (FISH) using a DGS region-specific probe and a control probe on nuclei released from thick sections. The diagnosis was confirmed in four of the six specimens, which provided valuable results, and in none of the controls. This study supports the feasibility and usefulness of FISH genotyping of archival autoptic material, which improves and assists the counselling procedures.

Autopsy↗
PubMed1996

Molecular studies in three patients with isodicentric Y chromosome.

Three patients carrying an isodicentric (idic) Y chromosome associated with a mosaic 45,X cell line were studied using molecular techniques. Genotype-phenotype correlations suggested an effect of the 45,X cell line on sexual differentiation. A relationship was established between instability of the idic(Y) chromosome and localization of the breakpoint on Yq, and between azoospermia and deletion of interval 6 on Yq.

Adult↗
PubMed1996

cDNA characterization and chromosomal mapping of two human homologues of the Drosophila dishevelled polarity gene.

The Drosophila dishevelled gene (dsh) encodes a secreted glycoprotein, which regulates cell proliferation, acting as a transducer molecule for developmental processes, including segmentation and neuroblast specification. We have isolated and characterized cDNA clones from two different human dsh-homologous genes, designated as DVL-1 and DVL-3. DVL-1 and DVL-3 putative protein products show 64% amino acid identity. The DVL-1 product is 50% identical to dsh and 92% to a murine dsh homologue (Dvl-1). Both human DVL genes are widely expressed in fetal and adult tissues, including brain, lung, kidney, skeletal muscle and heart. DVL-1 locus maps to chromosome 1p36 and DVL-3 to chromosome 3q27. DVL-1 locus on chromosome 1 corresponds to the murine syntenic region where Dvl-1 is located. DVL-1 and DVL-3 are members of a human dsh-like gene family, which is probably involved in human development. Although the precise role of these genes in embryogenesis is only conjectural at present, the structural and evolutionary characteristics suggest that mutations at their loci may be involved in neural and heart developmental defects.

Adaptor Proteins, Signal Transducing↗
PubMed1996

Microdeletions in interval 6 of the Y chromosome detected by STS-PCR in 6 of 33 patients with idiopathic oligo- or azoospermia.

It has been proposed that interval 6 of the human Y chromosome contains the gene or genes that control spermatogenesis (AZF, azoospermia factor). We have studied this region in 33 patients with oligo- or azoospermia, using PCR amplification of the YRRM1 (RBM1) gene and of 13 sequence-tagged sites (STSs), all mapping within interval 6. Six of the 33 patients showed no amplification of specific STSs, whereas there was no failure of amplification in normal male controls. We deduce that these six patients had microdeletions in interval 6 of the Y chromosome that correlated with the oligo- or azoospermia of these individuals. On biopsy of the testis, two of these patients showed a low number of germ cells, and four showed arrest with spermatides. We conclude that PCR amplification of Y-specific regions is a powerful and very sensitive tool for screening infertile men.

Adult↗
PubMed1996

Morphometric and functional study of apoptotic cell chromatin.

Apoptosis is usually characterized by profound morphological nuclear changes. Chromatin undergoes a progressive condensation that eventually involves all the nucleus. At earlier stages chromatin appears as divided in compact and diffuse areas, while the nuclear pores disappear from the nuclear envelope that surrounds the compact areas, and cluster around diffuse chromatin. Here we have performed a morphometric study on the different chromatin areas of freeze-fractured apoptotic cell nuclei in order to investigate its morphometric and functional organization. We have found large portions of inactive chromatin aggregations corresponding to the dense cap-shaped patches, while domains of nucleosomic fibres have been identified in the diffuse chromatin areas. The correlation of the nucleosomic fibre/diffuse chromatin domain with the nuclear pore clusters is demonstrated, and its implications with a possible residual nuclear activity are discussed.

Journal Article↗
PubMed1996

FISH detection of mixed chimerism in 33 patients submitted to bone marrow transplantation.

Fluorescence in situ hybridization (FISH) and cytogenetic analysis were carried out in 33 transplanted patients suffering from different hematologic disease using probes for X and Y chromosomes and ABL and BCR genes. FISH showed that recipient cells were invariably present during post-transplant follow-up. Stable minimal residual disease was associated with clinical and hematologic remission, while a progressive increase of host cells was strictly related with disease relapse. Cytogenetic investigation on the same samples showed recipient cells only in few cases. It was concluded that FISH analysis is useful for: (1) characterizing cases in which standard cytogenetic analysis has failed; (2) detecting host cells in sex-mismatched transplanted patients; and (3) evaluating Ph-negative CML with the BCR/ABL rearrangement. The possibility of detecting chromosome rearrangements in interphase nuclei using FISH analysis improves diagnosis and prediction of disease evolution and prompts earlier therapeutic approaches.

Adolescent↗
PubMed1996

Human homologue sequences to the Drosophila dishevelled segment-polarity gene are deleted in the DiGeorge syndrome.

DiGeorge syndrome (DGS) is a developmental defect of some of the neural crest derivatives. Most DGS patients show haploinsufficiency due to interstitial deletions of the proximal long arm of chromosome 22. Deletions of 22q11 have also been reported with patients with the velocardio-facial syndrome and familial conotruncal heart defects. It has been suggested that the wide phenotype spectrum associated with 22q11 monosomy is a consequence of contiguous-gene deletions. We report the isolation of human cDNAs homologous to the Drosophila dishevelled (dsh) segment-polarity gene. Sequences homologous to the 3' UTR of these transcripts (DVL-22) were positioned within the DGS critical region and were found to be deleted in DGS patients. Human DVL mRNAs are expressed in several fetal and adult tissues, including the thymus and, at high levels, the heart. Two transcripts, 3.2 and 5kb, were detected, in northern blot analysis, with different expression patterns in the surveyed tissues when different cDNAs were used. The isolated cDNAs exhibit high amino acid homology with the mouse and Xenopus Dvl-1 gene, the only other vertebrate dsh homologues so far isolated. The pivotal role of dsh in fly development suggests an analogous key function in vertebrate embryogenesis of its homologue genes. Since DGS may be due to perturbation of differentiation mechanisms at decisive embryological stages, a Dsh-like gene in the small-region overlap (SRO) might be a candidate for the pathogenesis of this disorder.

Adaptor Proteins, Signal Transducing↗
PubMed1995

Identification of multiple transcribed sequences from the spinal muscular atrophy region of human chromosome 5.

We report the isolation and characterization of novel expressed sequences from the spinal muscular atrophy (SMA) region on human chromosome 5q13. Based on the sequence homology studies these cDNAs were grouped in four classes, one of which shows extensive homologies with the beta-glucuronidase (BG) gene, differing in exon arrangement. The other cDNAs do not show any strong homology with known DNA sequences.

Base Sequence↗
PubMed1995

Fetal translocation between chromosomes 2, 18, and 21 resolved by fish.

An apparently balanced t(2q;21q) translocation was discovered in fetal blood and amniocytes of a 22-week fetus, monitored because of ultrasonographic evidence of a heart disease. FISH (fluorescence in situ hybridization) analysis disclosed a complex translocation between chromosomes 2q, 18q, and 21q, which was inherited from the healthy mother. This observation corroborates the usefulness of molecular cytogenetic techniques in raising the quality of prenatal diagnosis and detecting subtle rearrangements not resolved by standard cytogenetics.

Adult↗
PubMed1995

Retrospective investigation of hematopoietic chimerism after BMT by PCR amplification of hypervariable DNA regions.

We report on nine patients submitted to BMT with sex-matched donors and investigated by means of PCR amplification of the VNTRs ApoB, D1S80, DXS52, and D17S5. In all cases it was possible to detect a polymorphism able to distinguish between donor and patient cells, thus allowing us to recognize the presence of complete or mixed chimerism. In eight patients PCR analysis showed a complete chimerism during the entire follow-up. Only one of these patients relapsed, while the others are alive and without any sign of relapse 56.2 months (mean) after BMT. Mixed chimerism was detected in only one patient, who relapsed 3 months after this finding. These results confirm the usefulness of the study of PCR-amplified VNTRs in the assessment of marrow engraftment after BMT, mostly in sex-matched transplants where, in the absence of specific chromosome rearrangements, cytogenetic or FISH analysis cannot be used.

Adolescent↗