A hybrid zone with coincident clines for autosomal and sex-specific markers in the Sorex araneus group.

In hybrid zones, endogenous counter-selection of hybrids is usually first expressed as reduced fertility or viability in hybrids of the heterogametic sex, a mechanism known as Haldane's rule. This phenomenon often leads to a differential of gene flow between sex-linked markers. Here, we address the possibility of a differential gene flow for Y chromosome, mtDNA and autosomal markers across the hybrid zone between the genetically and chromosomally well-differentiated species Sorex antinorii and Sorex araneus race Vaud. Intermarker comparison clearly revealed coincidental centre and very abrupt clines for all three types of markers. The overall level of genetic differentiation between the two species must be strong enough to hinder asymmetric introgression. Cyto-nuclear mismatches were also observed in the centre of hybrid zone. The significantly lower number of mismatches observed in males than in females possibly results from Y chromosome-mtDNA interactions. Results are compared with those previously reported in another hybrid zone between S. antinori and S. araneus race Cordon.

Extra microchromosome mosaicism in amniotic cells confirmed in fetal tissues.

Mosaicism for an extra microchromosome was discovered in amniotic cell cultures of a 39-year-old woman. Using G, Q, C bands and silver staining, it was concluded that the extra chromosome was bisatellited. Parents' karyotype was normal. Parents elected for termination of the pregnancy. The presence of the extra microchromosome was confirmed in various tissues of the aborted fetus. The literature on the subject is briefly reviewed.

Proximal 11p deletion syndrome (P11pDS): additional evaluation of the clinical and molecular aspects.

The combination of multiple exostoses (EXT) and enlarged parietal foramina (foramina parietalia permagna, FPP) represent the main features of the proximal 11p deletion syndrome (P11pDS), a contiguous gene syndrome (MIM 601224) caused by an interstitial deletion on the short arm of chromosome 11. Here we present clinical aspects of two new P11pDS patients and the clinical follow-up of one patient reported in the original paper describing this syndrome. Recognised clinical signs include EXT, FPP, mental retardation, facial asymmetry, asymmetric calcification of coronary sutures, defective vision (severe myopia, nystagmus, strabismus), skeletal anomalies (small hands and feet, tapering fingers), heart defect, and anal stenosis. In addition fluorescence in situ hybridisation and molecular analysis were performed to gain further insight in potential candidate genes involved in P11pDS.

Contribution à la cytotaxonomie des Soricidés (Mammalia, Insectivora) de l'Afrique occidentale.

Chromosomes analysis of 28 shrews belonging to the genus Crocidura from West Africa allowed the detection of five new karyotypes: C. wimmeri (2n = 50, NF = 84), C. cf. gracilipes (56/86), C. cf. nimbae (46/68), and C. cf. planiceps (44/72). Among the individuals identified morphologically as C. poensis (52/70) a distinct species was recognized on the basis of its chromosome complement, C. nigeriae (50/76). The karyotype of C. occidentalis was confirmed with the study of another subspecies, C. occidentalis manni (50/66). An identical chromosome set characterizes C. odorata giffardi and provides evidence for its relationship with C. occidentalis.

Prediction of 18-month survival in patients with primary myelodysplastic syndrome. A regression model and scoring system based on the combination of chromosome findings and the Bournemouth score.

The predictive potential of six selected factors was assessed in 72 patients with primary myelodysplastic syndrome using univariate and multivariate logistic regression analysis of survival at 18 months. Factors were age (above median of 69 years), dysplastic features in the three myeloid bone marrow cell lineages, presence of chromosome defects, all metaphases abnormal, double or complex chromosome defects (C23), and a Bournemouth score of 2, 3, or 4 (B234). In the multivariate approach, B234 and C23 proved to be significantly associated with a reduction in the survival probability. The similarity of the regression coefficients associated with these two factors means that they have about the same weight. Consequently, the model was simplified by counting the number of factors (0, 1, or 2) present in each patient, thus generating a scoring system called the Lausanne-Bournemouth score (LB score). The LB score combines the well-recognized and easy-to-use Bournemouth score (B score) with the chromosome defect complexity, C23 constituting an additional indicator of patient outcome. The predicted risk of death within 18 months calculated from the model is as follows: 7.1% (confidence interval: 1.7-24.8) for patients with an LB score of 0, 60.1% (44.7-73.8) for an LB score of 1, and 96.8% (84.5-99.4) for an LB score of 2. The scoring system presented here has several interesting features. The LB score may improve the predictive value of the B score, as it is able to recognize two prognostic groups in the intermediate risk category of patients with B scores of 2 or 3. It has also the ability to identify two distinct prognostic subclasses among RAEB and possibly CMML patients. In addition to its above-described usefulness in the prognostic evaluation, the LB score may bring new insights into the understanding of evolution patterns in MDS. We used the combination of the B score and chromosome complexity to define four classes which may be considered four possible states of myelodysplasia and which describe two distinct evolutional pathways.

Clinical, molecular, and prognostic significance of WHO type inv(3)(q21q26.2)/t(3;3)(q21;q26.2) and various other 3q abnormalities in acute myeloid leukemia.

PURPOSE: Acute myeloid leukemia (AML) with inv(3)(q21q26.2)/t(3;3)(q21;q26.2) [inv(3)/t(3;3)] is recognized as a distinctive entity in the WHO classification. Risk assignment and clinical and genetic characterization of AML with chromosome 3q abnormalities other than inv(3)/t(3;3) remain largely unresolved. PATIENTS AND METHODS: Cytogenetics, molecular genetics, therapy response, and outcome analysis were performed in 6,515 newly diagnosed adult AML patients. Patients were treated on Dutch-Belgian Hemato-Oncology Cooperative Group/Swiss Group for Clinical Cancer Research (HOVON/SAKK; n = 3,501) and German-Austrian Acute Myeloid Leukemia Study Group (AMLSG; n = 3,014) protocols. EVI1 and MDS1/EVI1 expression was determined by real-time quantitative polymerase chain reaction. RESULTS: 3q abnormalities were detected in 4.4% of AML patients (288 of 6,515). Four distinct groups were defined: A: inv(3)/t(3;3), 32%; B: balanced t(3q26), 18%; C: balanced t(3q21), 7%; and D: other 3q abnormalities, 43%. Monosomy 7 was the most common additional aberration in groups (A), 66%; (B), 31%; and (D), 37%. N-RAS mutations and dissociate EVI1 versus MDS1/EVI1 overexpression were associated with inv(3)/t(3;3). Patients with inv(3)/t(3;3) and balanced t(3q21) at diagnosis presented with higher WBC and platelet counts. In multivariable analysis, only inv(3)/t(3;3), but not t(3q26) and t(3q21), predicted reduced relapse-free survival (hazard ratio [HR], 1.99; P < .001) and overall survival (HR, 1.4; P = .006). This adverse prognostic impact of inv(3)/t(3;3) was enhanced by additional monosomy 7. Group D 3q aberrant AML also had a poor outcome related to the coexistence of complex and/or monosomal karyotypes and cryptic inv(3)/t(3;3). CONCLUSION: Various categories of 3q abnormalities in AML can be distinguished according to their clinical, hematologic, and genetic features. AML with inv(3)/t(3;3) represents a distinctive subgroup with unfavorable prognosis.

Genome-wide arrays in routine diagnostics of hematological malignancies.

Over the last three decades, cytogenetic analysis of malignancies has become an integral part of disease evaluation and prediction of prognosis or responsiveness to therapy. In most diagnostic laboratories, conventional karyotyping, in conjunction with targeted fluorescence in situ hybridization analysis, is routinely performed to detect recurrent aberrations with prognostic implications. However, the genetic complexity of cancer cells requires a sensitive genome-wide analysis, enabling the detection of small genomic changes in a mixed cell population, as well as of regions of homozygosity. The advent of comprehensive high-resolution genomic tools, such as molecular karyotyping using comparative genomic hybridization or single-nucleotide polymorphism microarrays, has overcome many of the limitations of traditional cytogenetic techniques and has been used to study complex genomic lesions in, for example, leukemia. The clinical impact of the genomic copy-number and copy-neutral alterations identified by microarray technologies is growing rapidly and genome-wide array analysis is evolving into a diagnostic tool, to better identify high-risk patients and predict patients' outcomes from their genomic profiles. Here, we review the added clinical value of an array-based genome-wide screen in leukemia, and discuss the technical challenges and an interpretation workflow in applying arrays in the acquired cytogenetic diagnostic setting.

Monosomal karyotype in acute myeloid leukemia: a better indicator of poor prognosis than a complex karyotype.

PURPOSE: To investigate the prognostic value of various cytogenetic components of a complex karyotype in acute myeloid leukemia (AML). PATIENTS AND METHODS: Cytogenetics and overall survival (OS) were analyzed in 1,975 AML patients age 15 to 60 years. RESULTS: Besides AML with normal cytogenetics (CN) and core binding factor (CBF) abnormalities, we distinguished 733 patients with cytogenetic abnormalities. Among the latter subgroup, loss of a single chromosome (n = 109) conferred negative prognostic impact (4-year OS, 12%; poor outcome). Loss of chromosome 7 was most common, but outcome of AML patients with single monosomy -7 (n = 63; 4-year OS, 13%) and other single autosomal monosomies (n = 46; 4-year OS, 12%) did not differ. Structural chromosomal abnormalities influenced prognosis only in association with a single autosomal monosomy (4-year OS, 4% for very poor v 24% for poor). We derived a monosomal karyotype (MK) as a predictor for very poor prognosis of AML that refers to two or more distinct autosomal chromosome monosomies (n = 116; 4-year OS, 3%) or one single autosomal monosomy in the presence of structural abnormalities (n = 68; 4-year OS, 4%). In direct comparisons, MK provides significantly better prognostic prediction than the traditionally defined complex karyotype, which considers any three or more or five or more clonal cytogenetic abnormalities, and also than various individual specific cytogenetic abnormalities (eg, del[5q], inv[3]/t[3;3]) associated with very poor outcome. CONCLUSION: MK enables (in addition to CN and CBF) the prognostic classification of two new aggregates of cytogenetically abnormal AML, the unfavorable risk MK-negative category (4-year OS, 26% +/- 2%) and the highly unfavorable risk MK-positive category (4-year OS, 4% +/- 1%).

A non-random chromosome abnormality found in precursor-B lineage acute lymphoblastic leukaemia: dic(9;20)(p1?3;q11).

A comparison of cytogenetical data on acute lymphoblastic leukaemia studied at four large European centres has revealed a non-random dicentric chromosome abnormality: dic(9;20) (p1?3;q11) in 10 patients, nine of whom were children. All had early precursor-B lineage ALL, and eight children had a non-standard risk clinical presentation. The origin of the dicentric chromosome was demonstrated using a range of chromosome banding techniques. This was confirmed by FISH using paints and centromeric probes for chromosomes 9 and 20, together with a number of cosmid probes. The follow-up time of these patients is presently too short and the number of patients too few to determine the prognostic significant of this chromosome abnormality.

Systemic mastocytosis with associated myeloproliferative disease and precursor B lymphoblastic leukaemia with t(13;13)(q12;q22) involving FLT3.

Systemic mastocytoses represent neoplastic proliferations of mast cells. In about 20% of cases systemic mastocytoses are accompanied by clonal haematopoietic non-mast cell-lineage disorders, most commonly myeloid neoplasms. A case of systemic mastocytosis carrying the characteristic mutation at codon 816 (D816V) in the KIT gene of mast cells, with two concurrent accompanying clonal haematopoietic non-mast cell-lineage disorders, chronic myeloproliferative disease, unclassifiable and precursor B lymphoblastic leukaemia is documented. Both accompanying clonal haematopoietic non-mast cell-lineage disorders carried the wild-type KIT gene, but had a novel t(13;13)(q12;q22) involving the FLT3 locus at 13q12. The chronic myeloproliferative disease, unclassifiable and the precursor B lymphoblastic leukaemia were cured by syngenous stem cell transplantation, but the systemic mastocytosis persisted for more than 10 years. The additional impact of molecular techniques on the correct diagnosis in haematological malignancies is highlighted, and evidence is provided that, apart from internal tandem duplications and mutations, FLT3 can be activated by translocations.

Genetic and karyotypic structure in the shrews of the Sorex araneus group: are they independent?

The species of the common shrew (Sorex araneus) group are morphologically very similar but exhibit high levels of karyotypic variation. Here we used genetic variation at 10 microsatellite markers in a data set of 212 individuals mostly sampled in the western Alps and composed of five karyotypic taxa (Sorex coronatus, Sorex antinorii and the S. araneus chromosome races Cordon, Bretolet and Vaud) to investigate the concordance between genetic and karyotypic structure. Bayesian analysis confirmed the taxonomic status of the three sampled species since individuals consistently grouped according to their taxonomical status. However, introgression can still be detected between S. antinorii and the race Cordon of S. araneus. This observation is consistent with the expected low karyotypic complexity of hybrids between these two taxa. Geographically based cryptic substructure was discovered within S. antinorii, a pattern consistent with the different postglaciation recolonization routes of this species. Additionally, we detected two genetic groups within S. araneus notwithstanding the presence of three chromosome races. This pattern can be explained by the probable hybrid status of the Bretolet race but also suggests a relatively low impact of chromosomal differences on genetic structure compared to historical factors. Finally, we propose that the current data set (available at http://www.unil.ch/dee/page7010_en.html#1) could be used as a reference by those wanting to identify Sorex individuals sampled in the western Alps.

Chromosome localization of microsatellite markers in the shrews of the Sorex araneus group.

The extremely high rate of karyotypic evolution that characterizes the shrews of the Sorex araneus group makes this group an exceptionally interesting model for population genetics and evolutionary studies. Here, we attempted to map 46 microsatellite markers at the chromosome arm level using flow-sorted chromosomes from three karyotypically different taxa of the Sorex araneus group (S. granarius and the chromosome races Cordon and Novosibirsk of S. araneus). The most likely localizations were provided for 35 markers, among which 25 were each unambiguously mapped to a single locus on the corresponding chromosomes in the three taxa, covering the three sexual chromosomes (XY1Y2) and nine of the 18 autosomal arms of the S. araneus group. The results provide further evidence for a high degree of conservation in genome organization in the S. araneus group despite the presence of numerous Robertsonian rearrangements. These markers can therefore be used to compare the genetic structure among taxa of the S. araneus group at the chromosome level and to study the role of chromosomal rearrangements in the genetic diversification and speciation process of this group.

The long-term culture of porcine urothelial cells and induction of urothelial stratification.

OBJECTIVE: To assess porcine urothelial cell cultures and the in vitro induction of urothelial stratification in long-term cultures, to study their morphological, functional and genetic behaviour, and thus provide potential autologous urothelium for tissue-engineered substitutes for demucosalized gastric or colonic tissue. MATERIALS AND METHODS: Primary cultures of porcine urothelium were established and the cells passaged thereafter. Cell specificity was confirmed by cytokeratin analysis, cell membrane stability assessed using lactate dehydrogenase leakage, cell de-differentiation by gamma-glutamyl transferase activity and genomic stability by karyotype investigations. Histology and scanning electron microscopy were performed to study the cultured cells and the stratified constructs. Furthermore, collagen matrices were tested as cell scaffolds. RESULTS: The cells were cultured for 180 days; 10 subcultures were established during this period. Stratification was induced in a culture flask and on a collagen matrix. Cytokeratins 7, 8, 17 and 18 were expressed in all cultures, and cell membranes were stable, with no evident de-differentiation. The cultures were stable in their genotype and no chromosomal aberrations were found. The histology and immunohistochemistry of the stratified porcine constructs, and cell membrane stability and cell de-differentiation, were compared with those in the human system. CONCLUSION: Pig and human urothelial cells can be cultured over a long period with no signs of senescence. Urothelial stratification can be induced in vitro. The collagen matrix seems to be an excellent scaffold, allowing cell adherence and growth.