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Z Zemanová

Publications and source records attributed to Z Zemanová.

At least 19 recordsLinked to original sources

NORs and their transcription competence during the cell cycle.

In human cells ribosomal genes are organized as clusters, NORs, situated on the short arms of acrocentric chromosomes. It was found that essential components of the RNA polymerase I transcription machinery, including UBF, can be detected on some NORs, termed "competent" NORs, during mitosis. The competent NORs are believed to be transcriptionally active during interphase. However, since individual NORs were not observed in the cell nucleus, their interphase status remains unclear. To address this problem, we detected the competent NORs by two commonly used methods, UBF immunofluorescence and silver staining, and combined them with FISH for visualization of rDNA and/or specific chromosomes. We found that the numbers of competent NORs on specific chromosomes were largely conserved in the subsequent cell cycles, with certain NOR-bearing homologues displaying a very stable pattern of competence. Importantly, those and only those NORs that were loaded with UBF incorporated bromo-uridine in metaphase after stimulation with roscovitine and in telophase, suggesting that competent and only competent NORs contain ribosomal genes transcriptionally active during interphase. Applying premature chromosome condensation with calyculin A, we visualized individual NORs in interphase cells, and found the same pattern of competence as observed in the mitotic chromosomes.

Cell Cycle↗

Molecular cytogenetic stratification of recurrent oligodendrogliomas: utility of interphase fluorescence in situ hybridization (I-FISH).

In oligodendroglial brain tumours, losses of chromosomal material of the short arm of chromosome 1 and long arm of chromosome 19 have been shown to predict responsiveness to chemotherapy and prolonged patients' survival. Therefore, the correct diagnosis of these genetic alterations in tumours of oligodendroglial origin is particularly important. To detect deletions of 1p36 and/or 19q13.3 in oligodendroglial cells we used dual-colour I-FISH with locus-specific DNA probes. I-FISH was performed on isolated whole cell nuclei, prepared from fresh non-fixed tumour tissue samples resuspended in media and processed using a standard cytogenetic procedure, thus bypassing the problem of nuclear truncation. We examined 16 patients with histologically proved oligodendrogliomas (5x oligodendroglioma, 9x anaplastic oligodendroglioma, 2x anaplastic oligoastrocytoma). The results of molecular cytogenetic analyses were correlated with morphological and clinical findings. Molecular cytogenetic analyses were successful in 15 patients and, due to a non-adequate tissue specimen, were uninformative in one patient only. Combined deletions 1p36/19q13 were proved in 13 patients. However, in six of them additional genetic alterations typical for high-grade astrocytoma were found, which could have negative influence on the prognosis. One patient had isolated deletion of 1p36 and another had a normal genetic pattern without any chromosomal alterations. In summary, I-FISH on isolated cell nuclei is a powerful tool for detecting chromosomal aberrations in tumour cells. A systematic molecular cytogenetic analysis may advance diagnosis, prognostic stratification, and targeted treatment of patients with brain tumours.

Adult↗

[Molecular cytogenetics in diagnostics of malignant diseases].

Malignant cell transformation can be defined as series of progressive genetic events which are happening in one cell clone in limited number of specific genes. These genes could be oncogenes and/or tumor suppressor genes (antioncogenes, recessive oncogenes). Each change regardless if it is associated with initiation or progression of cancer can be related to a chromosomal rearrangement. If the aberration is above the limit of the light microscope sensitivity, it should be detected by classical cytogenetic techniques. Therefore it was hypothesized that the molecular characteristics of chromosomal rearrangements will lead to identification of genes with pivotal role in cancerogenesis. And indeed, genes important for origin of tumors were identified in recurrent chromosomal breakpoints. Until now, more than 1800 breakpoints were identified. Oncocytogenetics has remarkably developed after the introduction of molecular methods with higher sensitivity (100 kb). We present a short review of molecular cytogenetic methods with a survey of specific recurrent translocations and deletions of chromosomes in several malignancies and their prognostic value is given.

Chromosome Aberrations↗

Corticosteroid regulation of colonic ion transport during postnatal development: methods for corticosteroid analysis.

Many mammalian species including human are immature at birth and undergo major developmental changes during suckling and weaning period. This problem is also conspicuous for the gastrointestinal tract that undergoes abrupt transitions coinciding with birth and weaning. This review deals with the maturation of ion transport functions in colon, the intestinal segment that plays an important role in sodium and potassium absorption and secretion. The purpose of the present review is to summarize the mechanism of sodium and potassium transport pathways and show how these transport processes change postnatally and how hormones, particularly corticosteroids, modify the pattern of development. Finally we describe some of the ways, how to analyze corticosteroid metabolism in target tissue.

Adrenal Cortex Hormones↗

Assessment of nephrotoxicity in the chick embryo: effects of cisplatin and 1,2-dibromoethane.

Morphological symptoms of mesonephric kidney damage were analysed in chick embryos treated with nephrotoxic agents--CDDP or DBE. The drugs were administered intraamniotically on ED 3 at doses 0.03 and 0.3 microg CDDP or 100 and 300 microg DBE per embryo. Body weight and absolute and relative measures of the mesonephroi (length, weight and form) were evaluated on ED 10. The higher doses of both agents affected the mass of this organ significantly. Simultaneously, a dose-dependent increase of renal malformations was detected in treated embryos, while the incidence of gross and cardiovascular defects was low (DBE) or absent (CDDP). Together with less pronounced effects on the total body growth, the results gave evidence for a higher sensitivity of the mesonephros to toxic insult when compared to the whole organism. A direct cytotoxic effect multiplied by concomitant injury of blood supply seemed to be the main cause of CDDP nephrotoxicity. In the case of DBE, damage to the mesonephros was probably associated with a primary impairment of the vascular network. The chick embryo in ovo provides a promising system for the assessment of nephrotoxic effects induced by prospective therapeutic agents and environmental contaminants during the prenatal period.

Animals↗

[Lymphocyte immunophenotyping and cytogenetics for more precise prognosis in patients with type B chronic lymphatic leukemia].

BACKGROUND: The B-chronic lymphocytic leukemia (B-CLL) has highly variable prognosis. Possibility of more relevant prognosis has a great impact for the beginning and mode of therapy. METHODS AND RESULTS: One hundred patients diagnosed as having B-CLL were included into the study. Beside usual examinations necessary to establish the diagnosis, cytogenetic examination for the detection of deletion 13q14, 17p13, 11q23 and trisomy 12 and immunophenotyping was done. The mean age of the patients was 58.2 years, there were 62 men and 38 women. 91 evaluated patients were divided into two groups--those with the steady disease (55 pts) and those with progressive disease (36 pts). No relation between the number of cytogenetic abnormalities and the Rai stage of the disease was found. We identified a relation between the bone marrow infiltration pattern (diffuse) and the number of cytogenetic abnormalities and the del 13q14 (p.05). Using the immunophenotyping of the lymphocytes we found a relation between the expression of CD38 and CD11c and the disease progression (p < 0.05). Neither of the method (FISH and immunophenotyping) revealed differences between results from bone marrow samples and those from peripheral blood. CONCLUSIONS: Though the cytogenetic (FISH) and immunophenotype evaluation at the time of diagnosis did not improve the ability to define better the clinical course of the B-CLL, we suggest to use both methods routinely as an important tool to identify patients who would develop the progressive disease.

Adult↗

[Long-term results of the UHKT-911 study of adult patients under 65 years of age with de novo acute myeloid leukemias without favorable karyotypes].

Between February 1991 and April 1994 induction chemotherapy of 32 adult consecutive patients under 65 years with de novo acute myeloid leukemias (AML) was started in the study UHKT-911. They were 19 women and 13 men, aged 18-63 (median 44) years. Their AML were classified according to the FAB classification: 3 M0, 3 M1, 9 M2, 14 M4, 3 M5. Induction chemotherapy consisted of 1-2 cycles with 3-4 doses of daunorubicin (DNR) 45 mg/m2/d i.v. and 14 doses of cytosine arabinoside (Ara-C) 200 mg/m2 per 3-h infusion every 12 hours. After the treatment patients, not being in complete remission, got the HD cycle with 10 high-doses of Ara-C 2000 mg/m2 per 3-h infusion every 12 hours i.v. and DNR 45 mg/m2/d i.v. on days 4 and 5, then the EMi cycle composed of etoposide 100 mg/m2/d i.v. for 5 days and mitozantrone 10-12 mg/m2/d i.v. on days 1, 3 and 5. Complete remission (CR) was achieved in 25 of 32 (78%) patients after 1-3 cycles. Five patients died between days 5 and 24 of treatment of infections, two patients were resistant to 4 cycles of induction therapy and survived 8.4 and 13.5 months. Three patients chose allogeneic bone marrow transplantation in their 1st CR from their relatives. Two of them have been living in CR for 115 a 110 months since diagnosis, the third died of sepsis on the day 52 after transplantation. Two patients in CR died of infections after their 2nd. consolidation cycle. Twenty patients in CR completed 2-4 consolidation cycles (1-3 HD, 1 EMi). Median of their CR duration was 17.8 (2-117) months. Relapse appeared in 12 cases after 4.4-34.8 (median 12.5) months, 8 patients (6 women and 2 men, aged 29-63 years) have remained longer than 5 years in their 1st. CR. Cytogenetic examination of their bone marrow showed a normal karyotype in 4 cases, 1x 46,XX,del(1)(p32p34), 1x 46,XX,16p+, 1x 47,XX,+mar, 1x 46,XX,del(5)(q22q33). After 62 months in CR a pancytopenia with dysplastic bone marrow changes developed in one of them, probably a secondary myelodysplastic syndrome, lasting for further 33 months. Event-free survival at 5 years was 27.5% (8/29 patients), significantly better (p = 0.046) against 7.5% (3/40) patients treated without HD cycles in the years 1982-1987. The same difference was observed in 7.5-year overall survival (p = 0.036) between the two studies, when 3 of 6 patients 60-64 years old remain in their 1. CR.

Acute Disease↗

[Rearrangements of 11q in patients with hematologic malignancies].

BACKGROUND: The aim of this study was to investigate the rearrangement of MLL gene in bone marrow cells of patients with hematological malignancies with various types of 11q aberrations. These aberrations have been observed in acute lymphoblastic and acute myeloid leukemias as well as in myelodysplasias and lymphomas. METHODS AND RESULTS: Correlations of clinical characteristics, type of aberrations, diagnoses and survival of patients were evaluated. Using classical cytogenetic techniques we found 11q aberration in 17 patients with different hematological malignancies. FISH with dual color locus specific probe for MLL gene was used to confirm or exclude the rearrangement of this gene. Whole chromosome painting probes and multicolor FISH were performed for identification of chromosomes involved in complex translocations. Balanced rearrangements of 11q were found in 3 patients, in 14 patients unbalanced aberrations were found with rearrangement (4), deletion (4) and amplification (2) of MLL gene. In 7 patients no rearrangement of MLL gene was found. CONCLUSIONS: Correlation between clinical characteristics, type of aberrations, diagnoses and survival of patients was not significant, therefore further studies of larger cohort of patients are necessary to evaluate the prognostic value of 11q rearrangement.

Adult↗

Location of the BCR/ABL fusion genes on both chromosomes 9q34 in Ph negative chronic myeloid leukemia.

We present two patients with Ph-negative chronic myeloid leukemia (CML) and fusion signal BCR/ABL on both chromosomes 9, located in region 9q34. The first case was a 27 years old man with CML. Molecular studies (RT-PCR) revealed the rearrangement in the major-BCR region and expression of chimeric BCR/ABL mRNA of b3a2 configuration. By classical cytogenetic studies (G-banding) karyotype 46,XY was found in short-term cultivated bone marrow cells and phytohemagglutinin (PHA) stimulated peripheral lymphocytes. FISH studies revealed the BCR/ABL fusion signals on both chromosomes 9 and green BCR signals on both chromosomes 22 in all mitoses studied. Detection of the alleles of ABL1 intragenic STR locus by fluorescence PCR followed by fragmentation analysis in the patient and his parents provided no information about transmission of the ABL gene. Quantitative assessment of BCR/ABL transcript level by RT-PCR showed 60 and 70% BCR/ABL positivity in two peripheral blood samples at 6,5 and 10,5 months after diagnosis, respectively, which does not correspond to the expression from two identical BCR/ABL hybrid genes. Therefore, the possible mechanism of the origin of two BCR/ABL fusion signals present on both chromosomes 9 could not be resolved and remains speculative. The second case was a 53 years old male with diagnosis of chronic phase of CML, with first sign of acceleration one month after diagnosis and death because of sepsis in blastic phase within four months. The cytogenetic findings were identical to those in case No. 1., i.e. karyotype 46, XY by G-banding, two BCR/ABL fusion signals on both chromosomes 9 and RT-PCR molecular studies proved b3a2 breakpoints. It is generally accepted that prognosis of the patients with fused BCR/ABL gene located on chromosome 9 is poor. The presence of two fused genes could be anticipated as two Ph chromosomes in accelerated and blastic phases of the disease. However, in our study, quantitative findings of BCR/ABL transcripts did not corresponded to the expression of two BCR/ABL genes originating from duplication. If this assumption is correct then the expression of both fused genes BCR/ABL was in case No. 1 equally suppressed and total expression reached about the level of one BCR/ABL gene.

Adult↗

Transepithelial potential in mesonephric nephrons of 7-day-old chick embryos in relation to the histochemically detected sodium pump.

In order to obtain basic information on the transport properties of differentiating embryonic nephrons, we examined the 7-day-old chick mesonephros by measuring the transtubular epithelial potential difference (TPD) and by histochemical detection of Na,K-ATPase activity. TPD as an indicator of the electrogenic transport was measured in individual segments of superficial nephrons in vivo. Their electric polarity was always lumen-negative. TPD was reduced by addition of 10 mM KCN applied to the mesonephric nephrons from the outside. In the proximal tubules, TPD was significantly lower (mean+/-SD: -1.0+/-0.5 mV) than in the distal and collecting tubules (-2.2+/-1.0 mV, p< or =0.05). Activity of the sodium pump was evaluated histochemically by detection of ouabain-sensitive potassium-dependent p-nitrophenyl phosphatase in cryostat sections of the mesonephros. The enzyme activity was demonstrated only in distal tubules and in the collecting ducts, but not in the proximal tubules. These findings have revealed significant differences between embryonic nephron segments: the distal tubule, in contrast to the proximal one, is supplied by the sodium pump and is able to generate higher TPD. Therefore, we consider that it is only the distal nephron, which possesses the ability of active transport.

4-Nitrophenylphosphatase↗

[Importance of prognostic factors in patients with chronic B-lymphocytic leukemia at the time of diagnosis].

BACKGROUND: B-chronic lymphocytic leukemia (B-CLL) is the most common adult leukemia in the Western countries. Any routinely used staging system does not distinguish exactly the probable course of the disease at the time of diagnosis. Therefore the new prognostic factors, which help to assess the optimal therapeutic plan of patients, are searched intensively. METHODS AND RESULTS: We evaluated 154 patients with the B-CLL at the time of diagnosis--133 of them were retrospectively divided into two groups--one with stable form and the other with progressive form of the disease. We compared these two groups of patients with some of the prognostic factors (absolute lymphocyte count, the level of C-reactive protein, lactatdehydrogenase, beta-2-microglobulin, tumour necrosis factor, the immunoglobulin levels, the expression of CD38, FMC7, surface immunoglobulins, the type of bone marrow infiltration, and the cytogenetic abnormalities (trisomy 12, del(13)(q14), del(17)(p13) a del(11)(q23)). We found higher absolute lymphocyte count, level of beta-2-mikroglobulin, tumour necrosis factor, expression of CD38, light chains lambda, lower expression of FMC7 and less frequent nodular type of bone marrow infiltration by the patients with progressive disease. The correlation of the cytogenetic abnormalities and the course of the disease or stage according to the RAI et al. [27] staging system were not significant may be due to the small number of evaluated patients and short period of follow up. CONCLUSION: The routine evaluation of some risk factors in patients with B-chronic lymphocytic leukemia at the time of diagnosis helps to distinguish those with the probable more aggressive course of the disease and have the implication for the design of risk-adapted treatment strategies. The prognostic impact of the cytogenetic abnormalities and other risk factors has to be evaluated on larger group of patients during longer follow up period and repeated evaluations.

Biomarkers, Tumor↗

[Fluorescent in situ hybridization (FISH) in the diagnosis of acute childhood lymphatic leukemia (ALL)].

Classical cytogenetic analysis plays an important role in the diagnosis, classification, therapy monitoring and prognosis of patients with leukemia. Many recurrent cytogenetic abnormalities with major prognostic values have been described in childhood ALL. Hyperdiploidy and/or t(12;21) are associated with good prognosis, whereas t(9;22) and/or rearrangements of MLL gene correlate with poor outcome and therefore early detection of these abnormalities is very important. FISH can overcome some limitations of conventional cytogenetic and molecular-genetic analyses and due to high sensitivity specific chromosomal aberrations in mitoses and/or interphase nuclei can be detected. In the Center of Oncocytogenetics of the 3rd Medical Department for assessment of hyperdiploidy and structural rearrangements we use double-color FISH with centromeric and/or locus-specific probes and complex aberrations are ascertained by whole chromosome painting probes and multicolor FISH. Among 275 children with ALL examined during the last 8 years by different FISH methods we found seven patients with translocation t(9;22) and 14 patients with MLL rearrangements in bone marrow cells. Since 1988 we focus on detection of hyperdiploidy and/or t(12;21). High hyperdiploidy was found in 35 children, 10 of them had further complex rearrangements. Translocation t(12;21) was proved in 37 patients and complex rearrangements were found in 22 of them. FISH, cytogenetic and molecular-genetic analyses become obligatory for the first diagnostic examination as well as for monitoring of treatment effect in children with ALL.

Child↗

[Multicolor fluorescence in situ hybridization (mFISH].

Various techniques are now available for wide genome screening of alterations in copy number, structure and expression of genes and DNA sequences. Molecular cytogenetics has special techniques of comparative genomic hybridization (CGH), spectral karyotyping (SKY) and multicolor FISH (mFISH). We present principles of these methods, their use in molecular cytogenetic examinations of patients. We quote our experience with mFISH for analyses of complex chromosomal rearrangements in neoplastic cells and identification of inborn supernumerary marker chromosome. Further, we also review the first experiences with multicolor high resolution banding of chromosome (mBAND). This method was used for analysis of bone marrow cells of patient with myelodysplastic syndrome and deletion of chromosome No. 5. With mBAND exact breakpoints were localized. Multicolor fluorescence methods mFISH and mBAND becones the new tools for more precise analyses of inborn and acquired numerical and structural chromosomal rearrangements.

Chromosome Deletion↗

[Deletion of the long arm of chromosome 5 in patients with hematologic malignancies].

Deletion of part of the long arm of chromosome 5 (5q-) is one of the most common structural aberrations in patients with myeloid disorders. The deletion is interstitial and the deleted segment is variable in size and breakpoint localization. Precise analysis of chromosomal breakpoints proved that band 5q31 is the most common deleted region. Extensive molecular studies have been performed to identify one or several tumor suppressor gene(s) in this critical region. Although these genes have not been identified as yet, the candidate genes are being intensively studied. Isolation and characterization of tumor suppressor genes will lead to the understanding of molecular mechanisms of normal hematopoiesis and that of leukemic transformation.

Chromosome Deletion↗

Embryotoxicity of 1,2-dibromoethane in chick embryos in ovo: early and late effects.

Embryotoxic effects of 1,2-dibromoethane (DBE), a compound still widely used in industry, have been analyzed using chick embryos in ovo. Administration on embryonic days (ED) 3,4 or 5 induced dose-dependent embryotoxicity, manifested namely as the early embryonic death. A serious disturbance of the vascular system represented probably the main cause of strong embryolethality and growth retardation in the group of survivors. Amniotic bands in the parietal region and defects of brain and aorta prevailed in the malformation spectrum registered on ED 10. The local character of early induced changes suggests a direct effect of DBE itself in the embryotoxic action. This process is probably accomplished through interaction with lipids in cell membranes owing to the hydrophobic character of DBE molecules. The results, however, did not exclude an involvement of reactive metabolites in final embryotoxicity via the formation of DNA-adducts. In any case, a decreasing embryotoxicity of DBE with the age of treated embryos documented that the onset of liver function, assumed to occur on ED 5, did not increase the efficacy of DBE bioactivation. Our results confirmed the short-term embryotoxic properties of DBE reported in rat embryonic cultures. In addition, the in ovo system enabled us to reveal also long-term consequences represented namely by the formation of amniotic bands, not detectable in studies in vitro. The results obtained with the chick embryo in ovo confirmed the suitability of this system for embryotoxicity testing.

Abnormalities, Drug-Induced↗

[The interphase fluorescence in situ hybridization (I-FISH) technique in patients with chronic lymphatic leukemia (CLL)].

BACKGROUND: Trisomy 12 was found to be the most frequent chromosomal aberration identified by conventional cytogenetic studies of bone marrow cells and peripheral lymphocytes of patients with CLL. Molecular-cytogenetic techniques which enable examination of dividing and/or non-diving interphase nuclei (I-FISH), proved existence of other chromosomal abnormalities, mainly deletions, which could have in CLL patients relation to the origin, course and prognosis of the disease. METHODS AND RESULTS: During the last two years bone marrow chromosomes of all patients with CLL were examined by G-banding and by I-FISH. The numerical changes of chromosome 12 were followed by centromeric DNA probe in dividing and non-dividing cells. The small deletions were ascertained by locus specific probes for 13q14 (Rb gene), 17p13 (p53 protein) and 11q23 (MLL gene). These genes are responsible for cell division and their function is probably in connection with neoplastic process. It is of interest whether numerical and structural chromosomal rearrangements are primary or secondary changes and what is their impact on etiology of CLL. 93 patients were examined by DNA prove CEP12 and trisomy 12 was found in 24 of them (25.8%), the range of the clone was 2.5-75.5% of the screened cells. Deletion del(13)(q14) was examined by probe D13S319 in 73 patients and proved in 24 of them (32.8%), pathological clone ranged 2.5-80.0% of the cells. Deletion del(17)(p13) was found in 14 patients out of 61 examined by probe LSI p53 (22.9%). The extent of the clone was 2.5-34.0% of examined cells. Deletion 11q23 was not ascertained in any of 11 patients by means of probe LSI 11q23 (MLL). All probes used for FISH were manufactured by VYSIS. CONCLUSIONS: FISH is very sensitive method, suitable for molecular-cytogenetic examination of leukemic patients. With I-FISH the deletion of 13q14 was ascertained as the most frequent chromosomal aberration in series of 73 patients with CLL. We continue to increase the number of patients screened by I-FISH with all eligible DNA probes and start the prospective study on patients with chromosomal pathology. We will correlate the immunophenotype, morphology, clinical course and prognosis with karyotypic findings.

Adult↗

Importance of using comparative genomic hybridization to improve detection of chromosomal changes in childhood acute lymphoblastic leukemia.

We used comparative genomic hybridization (CGH) and conventional cytogenetics (CC) to define chromosomal changes and to evaluate the usefulness of CGH in 65 patients having childhood acute lymphoblastic leukemia (ALL). Subsequently, fluorescence in situ hybridization (FISH) was used to evaluate the CGH and cytogenetic results. Comparative genomic hybridization revealed DNA copy number changes in 49 (75%) patients (including 7 patients with unsuccessful cytogenetics and 2 patients with normal karyotype). A total of 85 losses and 195 gains were detected. The most commonly gained chromosomes were 21 (35%), X (31%), 18 (27%), 10 (26%), 6 (25%), 17 (25%), 4 (23%), and 14 (22%). Losses were most frequently observed on chromosomes 9p (18%) and 12p (11%). Other losses were detected on chromosomes 13q (9%), 6q (9%), 7p (8%), and chromosome X (6%). Conventional cytogenetics revealed chromosomal changes in 53 (82%) patients. The employment of CGH and FISH together with CC analysis revealed chromosomal changes in 62 (95%) of the childhood ALL patients investigated. The CGH completed CC results in 36 patients; in 9 patients, the changes escaped detection without using CGH. The results of our study were compared to 6 other CGH studies previously reported. Our observations underline the benefits of supplementing routine cytogenetic investigation in childhood ALL by FISH and CGH, because small unbalanced changes may escape detection when conventional cytogenetics is the only diagnostic method used.

Adolescent↗