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Biomedical subjects

G Lendvai

Publications and source records attributed to G Lendvai.

7 recordsLinked to original sources
PubMed2003

Rapid response to artificial selection on flower size in Phlox.

Quantitative characters are often said to evolve rather slowly, taking many generations to exhibit appreciable differences among populations. We tested this notion experimentally by performing bi-directional selection on corolla diameter of plants from a wild population of Phlox drummondii for three generations. By monitoring flower size, tube length and stigma-anther proximity of flowers, we obtained the direct and indirect responses to selection, and calculated genetic correlations, realized and narrow sense heritabilities using offspring-mother regression. Realized heritability of flower size was high (0.83), whereas genetic correlations among traits were weak or not significant. The per-generation average of the response in corolla diameter was about 5%. We found that P. drummondii has a great capacity to respond rapidly to selection, and this capacity may be in part responsible for the observed high degree of differentiation within the species. We also concluded that rapid evolution of morphological floral traits is possible.

Analysis of Variance↗
PubMed2000

[Competitive polymerase chain reaction: a new method for measuring N-myc amplification].

The highly variable biological behaviour of neuroblastoma, a neoplasm which belongs to the family of primitive neuroectodermal tumours, is determined by its molecular pathological characteristics. Among them amplification of the N-myc gene is the most important factor in both therapeutic and prognostic points of view. Value of the amplification can be determined by different methods. The latest of them is the competitive polymerase chain reaction (PCR), essence of which is the parallel reaction of the target N-myc gene (exon 3.) and the endogen competitor CF gene (exon 3.) in the same reaction solution. The authors applied the method on 11 neuroblastoma cases diagnosed between 1994 and january of 1999. In three cases the amplification was determined also by fluorescens in situ hybridization (FISH). Six of the 11 cases were detected to have more than 10-fold, two of the six about 100-fold N-myc amplification. Results of the PCR and FISH correlated well. The two methods applied by the authors complete each other and are appropriate for determining the gene amplification which gives valuable prognostic and therapeutic information about the examined tumour.

Genes, myc↗
PubMed1998

Combined metaphase, interphase cytogenetic, and flow cytometric analysis of DNA content of pediatric acute lymphoblastic leukemia.

Eleven pediatric acute lymphoid leukemia patients were investigated for chromosomal aneuploidy by interphase cytogenetics using chromosome specific (peri)centromeric probes for all the somatic and sex chromosomes. Results were compared with metaphase cytogenetic and flow cytometric derived DNA aneuploidy data. Experiments performed on normal human cells using chromosome specific (peri)centromeric probes indicated that disomy could be recognized in a range of 89.1+/-2.7% (12.9)-96.8+/-0.2% (0.9) for the somatic chromosomes and in 98.1+/-0.4% (1.3) for the sex chromosomes. Using the cutoff level of the mean false monosomy and trisomy in the control cells +2 S.D., chromosome loss or gain for the somatic chromosomes could be revealed beyond a clonal ratio of 3.6-13.2% and 1.1-6.8%, respectively. The same value for the sex chromosomes was 3.5% and 0%, respectively. In 5 of 11 patients the leukemic cells proved to be diploid with all three methods at both gross DNA and chromosome levels. Interphase cytogenetics revealed chromosome loss or gain in all of the remaining six patients, however, the metaphase analysis indicated numerical aberration in only two patients. In one of them only the increased chromosome number could have been detected without identifying the chromosomes involved and in the other one the two methods indicated trisomy for a different chromosome. Flow cytometric data showed aneuploidy in three of the six aneuploid leukemia patients. The results suggest that interphase cytogenetics might be more accurate compared with flow cytometry and metaphase analysis to reveal aneuploidy.

Adolescent↗
PubMed1997

[Application of interphase cytogenetics for the determination of changes in the DNA content in acute childhood lymphoid leukemia].

The authors investigated the usefulness of the interphase cytogenetic approach to reveal numerical chromosomal abnormalities. Experiments performed on normal human cells using chromosome specific (peri)centromeric probes indicated that disomy was recognized in a range of 89.1 +/- 5.4%-96.8 +/- 0.4% for the somatic chromosomes and in 98.1 +/- 0.8% for the sex chromosomes. Using positivity threshold of mean percentage of the fals monosomy and trisomy + 2 SD, chromosome loss or gain for the somatic chromosomes could be revealed beyond clonal ratio of 3.6-13.2% and 1.1-6.8%, respectively. The same value for the sex chromosomes was 3.2% and 0%, respectively. Eleven pediatric acute lymphoid leukaemia were investigated for chromosomal aneuploidy by interphase cytogenetics using chromosome specific (peri)centromeric probes for all the somatic and sex chromosomes. Results were compared with metaphase cytogenetic and flow cytometry derived gross DNA aneuploidy data. In 5 cases the leukaemic cells proved to be diploid with all three methods at both gross DNA and chromosome levels. Interphase cytogenetics revealed chromosome loss or gain in all the remaining 6 cases, however, metaphase analysis indicated numerical aberration in only 2 patients. In one of them only the increased chromosome number could have been detected without identifying the chromosomes involved and in the other one the two methods indicated trisomy for not the same chromosome. Flow cytometry data showed aneuploidy in 3 out of the 6 aneuploid leukaemia. The results imply that interphase cytogenetics might be more accurate as compared with flow cytometry and metaphase analysis to reveale aneuploidy.

Age Factors↗