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PubMedDate not supplied

Prognostic significance of different biological markers (DNA index, PCNA index, apoptosis, p53, karyotype) in 126 adenocarcinoma gastric biopsies.

BACKGROUND: The different clinical evolution of gastric adenocarcinomas with the same clinico-pathologic characteristics prompted the authors to investigate the prognostic significance of different biological markers. METHODS: One hundred twenty-six preoperative cancer gastric biopsies, selected according the stage evaluated after following gastrectomy, were examined for DNA content by means the static cytometry, proliferating cell nuclear antigen (PCNA), p53 mutation, apoptosis by immunohistochemistry and karyotype using fluorescence in situ hybridization (FISH) techniques. RESULTS: The gastric cancers, ail belonging at stage III, were adenocarcinomas histologically typed as: 26 well differentiated (G1), 45 moderately differentiated (G2), 43 poorly differentiated (G3) and 12 of undifferentiated type with signet-ring cells. The tumours showed a prevalence of diploidy (68%), a mean PCNA-LI of 4.8%, trisomy of chromosome 7 in 40% of the cases, low presence of apoptosis (30%) and p53 mutation (17%). Only apoptosis was significantly correlated to histological diagnosis (p = 0.009). A multivariate analysis showed that the DNA content and PCNA-LI were the only independent prognostic markers for survival (p = 0.005 and p = 0.0002 respectively). CONCLUSIONS: The evaluation of these two biological variables, especially of the PCNA index, on gastric cancer biopsies may be useful in predicting the aggressiveness of each tumor and in identifying patients in need of additional perioperative therapies.

Adenocarcinoma↗
PubMed1985

The myelodysplastic syndromes: different evolution patterns based on sequential morphological and cytogenetic investigations.

Serial morphological and cytogenetic investigations were performed in 46 patients with the myelodysplastic syndrome (MDS). Twenty-one patients (45.5%) progressed to AML (greater than 30% blasts in bone marrow smears). Based on sequential determinations of percentages of bone marrow blasts, three patterns of evolution were observed in MDS. Patients with evolution pattern A (48%) had an apparently stable disease with minimal or no increase in bone marrow blasts. Exceptionally they developed new or additional chromosomal anomalies during the course of their disease. Cases in this group, who showed no abnormal localization of immature myeloid precursors (ALIP) at time of diagnosis experienced prolonged survival (median: 43 months), while ALIP positive patients had shorter survival times (median: 14 months), with high probability of early death from infections and/or bleeding problems. Patients with evolution pattern B (28%) initially had a morphologically stable disease, comparable to cases with evolution pattern A, but showed an abrupt shift from MDS to AML. Most of these patients (82%) were ALIP positive and a substantial proportion (46%) showed karyotype anomalies at diagnosis. The abrupt shift to AML in these patients was frequently (61.5%) associated with additional cytogenetic anomalies. Patients with evolution pattern C (24%) showed a gradual increase in bone marrow blasts. The majority of these cases (8/11) ultimately developed acute myeloid leukaemia (gradual progression to AML), whereas some patients (3/11) died from infections and/or haemorrhagic complications before they had reached the level of clinical AML. All of these patients were ALIP positive at diagnosis and no additional cytogenetic alterations occurred during evolution. Acquisition of new karyotypic anomalies during the course of MDS was almost invariably associated with abrupt shift to AML. From this retrospective study we conclude that evolution in MDS shows two important aspects, which seem to be preponderant in determining the course and outcome of the disease: one is the proliferative capacity and resulting growth advantage of the neoplastic clone over normal haematopoiesis, as measured by increasing percentages of bone marrow blasts in sequential aspirates; the other one is instability of the clone. Unstable clones have a high propensity to further intraclonal changes; they are expressed morphologically by the abrupt increase in bone marrow blasts and cytogenetically by the acquisition of new or additional karyotype anomalies.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

Inversion of chromosome 16 and dysplastic eosinophils in accelerated phase of chronic myeloid leukemia.

Abnormalities of chromosome 16, including inv(16)(p13q22), del(16)(q22), and t(16;16)(p13;q22), have been reported almost exclusively in association with acute myelomonocytic leukemia and are characteristically accompanied by abnormal eosinophils with dysplastic granules in the bone marrow. We observed an inv(16)(p13q22) in two patients with typical Philadelphia chromosome positive chronic myeloid leukemia (CML). The appearance of the abnormality of chromosome 16 was associated with acceleration of disease or onset of blast crisis and with the appearance in the bone marrow of abnormal eosinophils. In both cases the marrow karyotypes were 46,XY,t(9;22)(q34;q11)/46,XY,inv(16)(p13q22),t(9;22)(q34;q11). In these two patients the temporal association of the acquisition of the inversion 16 and the appearance of monocytoid cells and dysplastic eosinophils in the bone marrow further supports the relationship of this karyotypic abnormality with leukemic monocytoid and eosinophilic evolution. This secondary cytogenetic change appears to be an infrequent manifestation of specific phenotypic disease progression in CML.

Adult↗
PubMedDate not supplied

The chromosomes of the living coelacanth and their remarkable similarity to those of one of the most ancient frogs.

The karyotype of the coelacanth is reported for the first time. Latimeria chalumnae has a 48-chromosome karyotype that contains metacentric, subtelocentric, and telocentric chromosomes as well as microchromosomes. This karyotype is unlike those found in lung-fishes but is very similar to the 46-chromosome karyotype of one of the ancient frogs, Ascaphus truei.

Animals↗
PubMed1981

An assessment of the nature of chromosomal rearrangements in 18 species of Peromyscus (Rodentia: Cricetidae).

G- and C-banded karyotypes from 9 previously unstudied species of Peromyscus are described and compared to the 9 species described in the literature. Additional new data are presented for P. eremicus. A hypothetical evolutionary tree for the 18 species was constructed based on the assumption that, where possible, shared chromosomal rearrangements became established in a common ancestor. A minimum of 60 chromosomal rearrangements (34 heterochromatic additions and 26 pericentric inversions) were needed to construct the most parsimonious tree. Seven of the 18 species have heterochromatin in noncentromeric areas. Three times as many inversions have been identified in the 11 largest pairs as have been observed in the 12 smallest pairs. Peromyscine rodents are characterized by a pattern of chromosomal variation quite distinct from that described for other rodent genera, such as Sigmodon and Mus. Karyotypic orthoselection in rodents appears to be relatively common in closely related species.

Animals↗
PubMed1998

Comparative karyotype of pig and cattle using whole chromosome painting probes.

The extent and distribution of conserved chromosomal segments between pig and cattle chromosomes were established using hybridization of porcine chromosome painting probes on bovine metaphases. A total of 44 segments of conserved synteny were identified, resulting in a nearly complete coverage of the bovine karyotype. This study provides new data on chromosome evolution of mammals.

Animals↗
PubMed1996

Cell senescence and a mechanism of clonal evolution leading to continuous cell proliferation, loss of heterozygosity, and tumor heterogeneity: studies on two immortal colon cancer cell lines.

Extensive karyotypic analysis was performed on early and late passages of two continuous human cell lines, SW480 and SW620, that were derived from the same colon cancer patient. We cultivated these two cell lines in vitro for a period of 24 months and periodically examined their chromosome constitution. SW480 cells, from passage 138, were injected subcutaneously into 20 nude mice. The tumors that grew in nude mice were then cultivated in vitro for several passages to compare histopathologic findings and tumor growth patterns with clonal chromosomal profiles. Despite some karyotypic diversity, the two cell lines exhibited common marker chromosomes and followed similar patterns of evolution. During subsequent passages, acquisition of new chromosomal abnormalities gave rise to sidelines with a near-diploid genome that frequently underwent endoreduplication. Genomic instability seemed to play an important role in the emergence, growth, and subsequent elimination of the heterogenous sidelines by selection, clonal expansion, and cell death by senescence. Despite continuous growth, both the cell lines occasionally showed telomeric associations and random dicentric and multicentric formations. These lesions were considered evidence of cell senescence and were related to the disappearance of particular sidelines through evolution. Successful evolutionary steps were characterized by elimination of pre-existing marker chromosomes that were subsequently replaced in the karyotype by their cytologically intact homologous chromosomes possibly after selective endoreduplication. Frequent loss of heterozygosity for the chromosomes taking part in this process is postulated. We suggest that one of the mechanisms by which cancer cells bypass senescence may be related to their potential for continuous clonal diversification.

Animals↗
PubMedDate not supplied

The rat Nb2 lymphoma: a novel model for tumor progression.

Tumor progression of cancers is manifested by phenotypic property changes including development of hormone/growth factor independence and metastatic ability. The progression results from acquired genomic alterations leading to clonal heterogeneity and outgrowth of more aggressive and therapy-resistant sublines. Previously, a cultured rat "Nb2 lymphoma" cell line was established, whose viability depends critically on the hormone, prolactin, acting as the principal growth factor. By prolactin starvation, prolactin-independent sublines were generated which possessed the parent karyotype plus extra acquired chromosomal changes (clonal evolution). In this study, the parent line (Nb2-U17) and a cloned subline (SFJCD1) were compared for metastatic ability using single s.c. tumor transplants in Noble rats. Rats (22) bearing Nb2-U17 tumors showed no evidence of metastases at autopsy, even when tumors at implantation site reached a size of 9 cm (length + width). In contrast, rats (19) bearing SFJCD1 tumors showed multiple metastases (liver, kidney) when transplants exceeded 5 cm. This difference in metastatic ability may be related to the acquisition of an inversion in chromosome 1, i.e. inv(1)(q31q41). The 1q41 locus is adjacent to the reported H-ras-1 proto-oncogene locus (1q41-q42). In another subline, tetraploidization (flow cytometric analysis, karyotyping) occurred spontaneously following prolonged culturing (20 mo). Together, the parent Nb2 lymphoma line and its clonal derivatives provide a novel system for studying cellular and molecular mechanisms underlying tumor progression to the metastatic phenotype.

Animals↗
PubMed1979

Chromosomal evolution in primates: tentative phylogeny from Microcebus murinus (Prosimian) to man.

The karyotypes of more than 60 species of Primates are studied and compared, with the use of almost all existing banding techniques. There is a very close analogy of chromosome banding between the Simians studied and man. The quantitative or qualitative variations detected all involve the heterochromatin. It is very likely that all the euchromatin (nonvariable R and Q bands) is identical in all the species. Approximately 70% of the bands are common to the Simians and to the Lemurs (Prosimians). In the remaining 30%, technical difficulties prevented a valuable comparison, but this does not exclude the possibility that a complete analogy may exist. Thus, it is very likely that chromosomal evolutions of the Simians, and probably of all the Primates, has occurred without duplication or deficiency of the euchromatin. Approximately 150 rearrangements could be identified and related to the human chromosomes. The types of rearrangement vary from one group (suborder, family, genus) to another. For instance, Robertsonian translocations are preponderant among the Lemuridae (44/57), but are nonexistent among the Pongidae. Chromosome fissions are very frequent amng the Cercopithecidae (10/23), but were not found elsewhere, and pericentric inversions are preponderant in the evolution of Pongidae and man (17/28). This suggest that the chromosomal evolution may be directed by the genic constitution (favouring the occurrence of a particular type of rearrangement, by enzymatic reaction), by the chromosomal morphology (the probability that Robertsonian translocation will be formed depends at least partially on the number of acrocentrics), and by the reproductive behaviour of the animals. Reconstitution of the sequence of the chromosomal rearrangements allowed us to propose a fairly precise genealogy of many Primates, giving the positions of the Catarrhines, the Platyrrhines, and the Prosimians. It was also possible to reconstruct the karyotypes of ancestors that died out several dozen million years ago. The possible role of chromosomal rearrangements in evolution is discussed. It appears necessary to consider different categories of rearrangements separately, depending on their behaviour. The 'nonfavoured' rearrangements, such as pericentric inversions, need to occur in an isolated small population for implanting, by an equivalent of genic derivation. The 'favoured' rearrangements, e.g., Robertsonian translocations, may occur and diffuse in panmictic populations, and accumulate. Their role of gametic barrier could be much more progressive. For discrimination between these two categories, it was necessary to differentiate the selective advantage or disadvantage of the rearrangement itself. It was not possible to show that chromosomal rearrangements play a direct role in modification of the phenotype by position effect. Comparison of the rearrangement that have occurred during evolution and those detected in the human population shows a strong correlation for some of them...

Animals↗
PubMed1982

Chromosomal localization of 18S + 28S and 5S Ribosomal RNA genes in evolutionarily diverse anuran amphibians.

The chromosomal locations of the 18S + 28S and 5S ribosomal RNA genes have been analyzed by in situ hybridization in ten anuran species of different taxonomic positions. The chosen species belong to both primitive and evolved families of the present day Anura. Each examined species has 18s + 28S rRNA genes clustered in one locus per haploid chromosome set: this locus is placed either in an intercalary position or proximal to the centromere, or close to the telomere. The 5S rRNA genes are arranged in clusters which vary in number from one to six per haploid set. The 5S rDNA sites are found in intercalary positions, at the telomeres, and at, or close to, the centromeres. Microchromosomes and small chromosomes in primitive karyotypes have been found to carry 5S rDNA sequences. The results are discussed in relation to ideas on the karyological evolution of Amphibia.

Animals↗
PubMed1981

Cytogenetic study of five species of Cercopithecus.

The G- and C-banded karyotypes of five species of Cercopithecus are reported. The chromosome numbers are: for C. ascanius katangae 2 n = 66 (XX); for C. petaurista petaurista 2 n = 66 (XY); for C. mona mona 2 n = 68 (XX); for C. pogonias grayi 2 n = 72 (XY) and for C. hamlyni 2 n = 64 (XY). We always found three types of chromosome: metacentric, sub-metacentric and acrocentric. The 'marker chromosomes' typical of the Cercopithecidae are of the last type. The karyotype of C. pogonias grayi shows a characteristic pair of acrocentric autosomes which is again found in the hybrid karyotypes.

Animals↗
PubMed1992

Chromosome banding in Amphibia. XVII. First demonstration of multiple sex chromosomes in amphibians: Eleutherodactylus maussi (Anura, leptodactylidae).

A cytogenetic study performed on a population of the South American leptodactylid frog Eleutherodactylus maussi revealed multiple sex chromosomes of the X1X1X2X2 female/X1X2Y male (= XXAA female/XXAY male) type. The diploid chromosome number is 2n = 36 in all females and 2n = 35 in most males. The multiple sex chromosomes originated by a centric fusion between the original Y chromosome and a large autosome. In male meiosis the X1X2Y (= XXAY) multiple sex chromosomes form a classical trivalent configuration. E. maussi is the first species discovered in the class Amphibia that is distinguished by a system of multiple sex chromosomes. Only one single male was found in the population with 2n = 36 chromosomes and lacking the Y-autosomal fusion. This karyotype (XYAA male) is interpreted as the ancestral condition, preceding the occurrence of the Y-autosome fusion.

Animals↗
PubMed1997

[Feasibility of analysis of macroevolutionary rearrangements of mammalian chromosomes].

In the Institute of Cytology and Genetics, Siberian Division, Russian Academy of Sciences, detailed studies on chromosome sets of humans and domestic animals were initiated and supported by D.I. Belyaev and started by S.I. Radzhabli. They believed that analysis of differentially stained chromosomes and mapping of the genomes of main commercial species provide for a better understanding of the processes that occurred during their evolution and domestication. Several new approaches to studying macroevolutionary karyotypic rearrangements associated with divergence of remote taxa, such as primates and paridigitate ungulates, are discussed.

Animals↗
PubMed2003

Structural characterization of chromosome I size variants from a natural yeast strain.

Many yeast strains isolated from the wild show karyotype instability during vegetative growth, with rearrangement rates of up to 10(-2) chromosomal changes per generation. Physical isolation and analysis of several chromosome I size variants of one of these strains revealed that they differed only in their subtelomeric regions, leaving the central 150 Kb unaltered. Fine mapping of these subtelomeric variable regions revealed gross alterations of two very similar loci, FLO1 and FLO9. These loci are located on the right and left arms, respectively, of chromosome I and encompass internal repetitive DNA sequences. Furthermore, some chromosome I variants lacking the FLO1 locus showed evidence of recombination at a DNA region on their right arm that is enriched in repeated sequences, including Ty LTRs. We propose that repetitive sequences in many subtelomeric regions in S. cerevisiae play a key role in karyotype hypervariability. As these regions encode several membrane-associated proteins, subtelomeric plasticity may allow rapid adaptive changes of the yeast strain to specific substrates. This pattern of semi-conservative chromosomal rearrangement may have profound implications, both in terms of evolution of wild strains and for biotechnological processes.

Blotting, Southern↗
PubMedDate not supplied

[Relationship between the study of DNA reassociation kinetics of various chromosomal forms of Ellobius and questions concerning the pathways of chromosome rearrangement during evolution].

Fifteen chromosome forms of Ellobius talpinus (from 2n = 31 to 2n = 54) were found in the small area in the Pamirs. Low-chromosome karyotypes evolved from 54-chromosomal ancestral form by Robertsonia centric fusions. The DNA reassociation kinetics of 34- and 54-chromosome forms of E. talpinus have been studied. For comparison DNA of E. lutescens (2n = 17) the karyotype of which seems to have arisen from 54-chromosome ancestor by Robertsonian and other types rearrangements was examined. Reassociation profiles of Ellobius DNA suggest the existence of several repeated sequences families with different frequences of repetitions. The reassociation curves of DNA from 34- and 54-chromosome forms were identical. These data indicate absence of changes in DNA molecular organization during the evolution of E. talpinus karyotypes by Robertsonian fusions. Comparative analysis of DNA reassociation kinetics of E. talpinus and E. lutescens showed identical characteristics of highly repeated sequences and of one from the three intermediate fractions, however Cot 1/2, complexity and repetitive frequencies of two intermediate fractions of E. talpinus and E. lutescens were different. It is possible that non-robertsonian rearrangements of E. lutescens karyotype affected only intermediate repetitions. The alternative explanation of these data is a simple divergence of repeated sequences during the evolution of E. lutescens DNA.

Animals↗
PubMed1982

Chronic T-cell leukemias. II. Cytogenetic studies.

Chromosome abnormalities were documented in the PHA-stimulated lymphoid cells from 10 patients with chronic T-cell leukemias (6 T-PLL, 3 T-CLL and 1 T-LCL). One or more marker chromosomes were present in most metaphases in every case of T-PLL but they were different in each case. Structural abnormalities were also observed in T-CLL and T-LCL but less consistently. Chromosomes involved in marker formation in two or more cases were: Nos. 2, 7, 8, 9, 11 and 16. The karyotype was hypodiploid in five cases and hyperdiploid in two. Chromosomes Nos. 2 and 8 were the most frequently involved in structural and numerical abnormalities: Nos. 8 in 2 T-CLL and the 6 T-PLL and No. 2 in 1 T-CLL, 1 T-LCL and 5 T-PLL. Abnormalities of chromosome No. 2 are rare in human neoplastic disease but may be common in T-lymphoproliferative disorders. The differences between T-PLL and T-CLL reported here may have some bearing on the clinical features. T-PLL, characterised in all cases by clonal abnormalities, has an aggressive clinical course. In contrast, T-CLL with less consistent karyotypic changes has a protracted and benign clinical evolution.

Adult↗
PubMed2001

Cytotaxonomic considerations on Neotropical Psittacidae birds and description of three new karyotypes.

Chromosomes obtained from feather tissues of 14 species of Brazilian Psittacidae were analyzed by Giemsa conventional staining and the karyotypes of Ara chloroptera, Propyrrhura maracana and Nandayus nenday are presented for the first time. The remaining species showed no chromosome differences when compared with previous literature data. Two basic karyotype patterns were observed. A karyotype pattern is mostly characterized by biarmed macrochromosomes, while in the other one most macrochromosomes are telocentrics.

Animals↗