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PubMed2004

[Study of the clonality of cutaneous and blood lymphocytes during drug-induced hypersensitivity in 6 patients].

INTRODUCTION: The drug-induced hypersensitivity syndrome or DRESS (drug reaction with eosinophilia and systemic symptoms) is a severe toxiderma because it is accompanied by lethal visceral involvement in 6 to 10% cases. Its physiopathology remains unclear. In order to specify the immunological characteristics of this toxiderma we analyzed, prospectively, the rearrangement of the blood and cutaneous T-cell lymphocyte receptor (TCR) genes of patients exhibiting a drug-induced hypersensitivity syndrome between April 1998 and April 2000. PATIENTS AND METHODS: The inclusion criteria were: age over 18 years, occurrence of a drug-induced generalized eruption, existence of associated systemic involvement (lymph node or visceral), and presence of hypereosinophilia greater than 0.5 G/l and/or circulating atypical lymphocytes. Six patients (3 men and 3 women), with a mean age of 54 years were included. The imputable drug was an anti-seizure in 3 cases, allopurinol in 2 and oxazepam in one. Remission occurred within a delay of 10 to 30 days after the acute phase. Two patients presented several flares. RESULTS: No clonal rearrangement in TCR genes was detected in the cutaneous samples. A clonal rearrangement of TCR genes was initially detected in the blood lymphocytes of 3 out of the 6 patients (allopurinol: n=2 and oxazepam: n=1). The latter remained detectable during the evolution, during the second or third flare of the drug-induced hypersensitivity in 2 patients (allopurinol: n=1 and oxazepam: n=1). DISCUSSION: The presence of circulating T-cell clones detectable for several months after the occurrence of a drug-induced hypersensitivity shows the mono or oligoclonal expansion of activated T-cells, induced by the drug imputed. Their persistence over several months corresponds to a remnant activation of the immune system that can explain the prolonged and/or recurrent evolution of the drug-induced hypersensitivity syndrome in some patients.

Adult↗
PubMed1991

In situ studies of the primary immune response to (4-hydroxy-3-nitrophenyl)acetyl. I. The architecture and dynamics of responding cell populations.

After primary immunization with an immunogenic conjugate of (4-hydroxy-3-nitrophenyl)acetyl, two anatomically and phenotypically distinct populations of antibody-forming cells arise in the spleen. As early as 2 d after immunization, foci of antigen-binding B cells are observed along the periphery of the periarteriolar lymphoid sheaths. These foci expand, occupying as much as 1% of the splenic volume by day 8 of the response. Later, foci grow smaller and are virtually absent from the spleen by day 14. A second responding population, germinal center B cells, appear on day 8-10 and persist at least until day 16 post-immunization. Individual foci and germinal centers represent discrete pauciclonal populations that apparently undergo somatic evolution in the course of the primary response. We suggest that foci may represent regions of predominantly interclonal competition for antigen among unmutated B cells, while germinal centers are sites of intraclonal clonal competition between mutated sister lymphocytes.

Animals↗
PubMedDate not supplied

A molecular strategy for the study of bacterial invasion.

Bacterial populations are often clonal, and even within a bacterial species, the frequency of gene exchange and recombination is quite low. Consequently, mobile genetic elements--plasmids, bacteriophages, and transposons--have been the central factors in the evolution of pathogenic traits. One central feature of pathogenicity, the capacity to enter epithelial cells, is encoded by the bacterial chromosome of Yersinia pseudotuberculosis but by plasmid genes in enteroinvasive Escherichia coli. A single Yersinia gene, inv, which encodes a single 107,000-dalton protein, can be cloned in E. coli K12, and its presence is sufficient to permit the bacteria to enter cultured human cells. In contrast, fully 70 kilobases of a virulence plasmid from enteroinvasive E. coli must be transferred to E. coli K12 to achieve the same result. While researchers are at the early stages of understanding microbial entry into host cells, they can now investigate the molecular basis of this event in greater detail than has previously been possible.

Animals↗
PubMed2025

Impact of the ECM on the Mechanical Memory of Cancer Cells.

Besides genomic and proteomic analyses of bulk and individual cancer cells, cancer research focuses on the mechanical analysis of cancers, such as cancer cells. Throughout the oncogenic evolution of cancer, mechanical inputs are stored as epigenetic memory, which ensures versatile coding of malignant characteristics and a quicker response to external environmental influences in comparison to solely mutation-based clonal evolutionary mechanisms. Cancer's mechanical memory is a proposed mechanism for how complex details such as metastatic phenotypes, treatment resistance, and the interaction of cancers with their environment could be stored at multiple levels. The mechanism appears to be similar to the formation of memories in the brain and immune system like epigenetic alterations in individual cells and scattered state changes in groups of cells. Carcinogenesis could therefore be the outcome of physiological multistage feedback mechanisms triggered by specific heritable oncogenic alterations, resulting in a tumor-specific disruption of the integration of the target site/tissue into the overall organism. This review highlights and discusses the impact of the ECM on cancer cells' mechanical memory during their metastatic spread. Additionally, it demonstrates how the emergence of a mechanical memory of cancer can give rise to new degrees of individuality within the host organism, and a connection to the cancer entity is established by discussing a connection to the metastasis cascade. The aim is to identify common mechanical memory mechanisms of different types of cancer. Finally, it is emphasized that efforts to identify the malignant potency of tumors should go way beyond sequencing approaches and include a functional diagnosis of cancer physiology and a dynamic mechanical assessment of cancer cells.

Humans↗
PubMed2000

[Epidemiology, origin and genetic diversity of HTLV-1 retrovirus and STLV-1 simian affiliated retrovirus].

Human T Cell leukemia/lymphoma virus type I, the first human oncogenic retrovirus, is the aetiological factor of Adult T cell leukemia (ATL), a CD4+ malignant lymphoproliferative disease and of a chronic neuromyelopathy, the tropical spastic paraparesis or HTLV-1 associated myelopathy (TSP/HAM). HTLV-1, which infects from 15 to 25 million individuals world-wide, is highly endemic in certain areas such as south-western Japan, Central Africa, the Caribbean basin and some regions of South America, Melanesia and of the middle East (for example the Mashhad area of Iran). The three major modes of transmission for HTLV-1 infection are perinatal, sexual and by blood transfusion. Recent molecular studies on HTLV-1 have shown the existence of several molecular subtypes (genotypes). These are related to the geographical origin of the infected populations and not to the associated diseases. The virus has a very high genetic stability. Viral amplification via clonal expansion of infected cells, rather than by use of reverse transcription could explain this remarkable phenomenon which can be used as a molecular tool for gaining new insights into the origin, evolution and modes of dissemination of HTLV-1. Analyses of HTLV-1 and STLV-1 (the simian counterpart) viral strains from throughout the world suggest that four events are responsible for this pattern of dissemination: 1) the transmission in the wild of STLV-1 between simian species, 2) the transmission of STLV-1 to humans as exemplified by the high percentage of identity between STLV-1 strains from chimpanzees or from mandrills with some HTLV-1 strains present in inhabitants of Central Africa, 3) persistence of HTLV-1 over a long period of time (by sexual and perinatal transmissions) in remote populations, as seen in the Australo-Melanesian region and 4) a global distribution of HTLV-1 via large scale human migrations, e.g., the slave trade from Africa to the New World.

Animals↗
PubMed2002

[Genetic structure of a diploid-polyploid complex of the spined loach Cobitis taenia (Cypriniformes: Cobitidae) from the middle Dnieper bassin].

Biochemical genetic typing and cytometry showed that polyploid females account for 87% of the spined loach Cobitis taenia population from the middle Dnieper basin. The polyploidy series included triploids, tetraploids, and, possibly, a few pentaploids. A characteristic feature of the genetic structure of polyploids was that their genetic variation was due to the clonal variation in the haploid portion of the genome originating from Cobitis sp. and to polymorphism of the diploid portion originating from C. taenia. The results are discussed with regard to comparative evolution of alloploid complexes in fish and terrestrial vertebrates.

Animals↗
PubMed2006

Repetitive DNA elements as mediators of genomic change in response to environmental cues.

There is no logical or theoretical barrier to the proposition that organismal and cell signaling could transduce environmental signals into specific, beneficial changes in primary structure of noncoding DNA via repetitive element movement or mutation. Repetitive DNA elements, including transposons and microsatellites, are known to influence the structure and expression of protein-coding genes, and to be responsive to environmental signals in some cases. These effects may create fodder for adaptive evolution, at rates exceeding those observed for point mutations. In many cases, the changes are no doubt random, and fitness is increased through simple natural selection. However, some transposons insert at specific sites, and certain regions of the genome exhibit selectively and beneficially high mutation rates in a range of organisms. In multicellular organisms, this could benefit individuals in situations with significant potential for clonal expansion: early life stages or regenerative tissues in animals, and most plant tissues. Transmission of the change to the next generation could occur in plants and, under some circumstances, in animals.

Animals↗
PubMed2001

Evolution in action through hybridisation and polyploidy in an Iberian freshwater fish: a genetic review.

The Iberian minnow Leuciscus alburnoides represents a complex of diploid and polyploid forms with altered modes of reproduction. In the present paper, we review the recent data on the origin, reproductive modes, and inter-relationships of the various forms of the complex, in order to predict its evolutionary potential. The complex follows the hybrid-origin model suggested for most other asexual vertebrates. Diploid and triploid females from the southern river basins exhibit reproductive modes that cannot be conveniently placed into the categories generally recognised for these vertebrate complexes, which imply continuous shifting between forms, where genomes derived from both parental ancestors are cyclically lost, gained or replaced. Replacement of nuclear genomes allow the introduction of novel genetic material, that may compensate for the disadvantages of asexual reproduction. Contrasting with most other vertebrate complexes, L. alburnoides males are fertile and play an important role in the dynamics of the complex. Moreover, diploid hybrid males may have initiated a tetraploidization process, when a diploid clonal sperm fertilised a diploid egg. This direct route to tetraploidy by originating fish with the right constitution for normal meiosis (symmetric), may eventually lead to a new sexually reproducing polyploid species. This case-study reinforces the significance of hybridisation and polyploidy in evolution and diversification of vertebrates.

Animals↗
PubMed2005

Dissemination of transferable CTX-M-type extended-spectrum beta-lactamase-producing Escherichia coli in Korea.

AIMS: Among 365 Escherichia coli isolated in 2003, 31 cefotaxime-resistant isolates were obtained from clinical specimens taken from adults hospitalized in Busan, Korea. Six extended-spectrum beta-lactamase (ESBL)-producing isolates were investigated further to determine the mechanism of resistance. METHODS AND RESULTS: These isolates were analysed by antibiotic susceptibility testing, pI determination, plasmid profiles, transconjugation test, PCR-restriction fragment length polymorphism (RFLP), enterobacterial repetitive consensus (ERIC)-PCR and DNA sequencing. All six of these isolates were found to contain the CTX-M-type ESBL genes. Five clinical isolates and their transconjugants produced CTX-M-3. One clinical isolate (K17391) and its transconjugant (trcK17391) produced CTX-M-15. Five clinical isolates also produced another TEM-1. One clinical isolate (K12776) also contained another TEM-52. CTX-M-3 ESBL gene was responsible for the resistance to piperacillin, cephalothin, cefotaxime, cefepime and aztreonam. CTX-M-15 or TEM-52 was especially responsible for the resistance to ceftazidime. CONCLUSIONS: These results appear to represent the in vivo evolution of CTX-M-type beta-lactamase genes (bla(CTX-M-3) --> bla(CTX-M-15)) under the selective pressure of antimicrobial therapy (especially ceftazidime). PCR-RFLP is a reliable method to discriminate CTX-M-15 gene from CTX-M-3 gene. ERIC-PCR analysis revealed that dissemination of CTX-M-3 was not due to a clonal outbreak of a resistant strain but to the intra-species spread of resistance to piperacillin, cephalothin, cefotaxime, cefepime and aztreonam in Korea. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of the occurrence of CTX-M-1 cluster ESBLs in Korea. A more comprehensive survey of these ESBL types from Korea is urgently needed because of the in vivo evolution of CTX-M-15 from CTX-M-3. The emergence of these CTX-M-type ESBLs suggests that diagnostic laboratories should screen for ESBLs with ceftazidime as well as cefotaxime; they should still perform clavulanate synergy tests on resistant isolates.

Adult↗
PubMed1980

Phenotypic evolution of cells resistant to bromodeoxyuridine.

Variants resistant to bromodeoxyuridine (BrdUrd) and deficient in thymidine kinase (ATP:thymidine 5'-phosphotransferase; EC 2.7.1.21) have been obtained from V79 Chinese hamster cells by a combination of spontaneous and drug-induced change. Initial mutations take place in wild-type populations as a facilitating step to give partially resistant clones that can be isolated by one-step selection in BrdUrd. When these tolerant populations are maintained for extended periods in BrdUrd-containing medium, a gradual phenotypic transition occurs in which BrdUrd appears to act as an inductive as well as selective agent. Thymidine kinase activity declines logarithmically over an interval of 8-10 weeks as the growth rate rises and the cells become completely resistant to BrdUrd. Relative plating efficiency in hypoxanthine/aminopterin/thymidine medium also decreases, but the decrease is not coordinate with shifts in thymidine kinase activity. The potential for colony formation in hypoxanthine/aminopterin/thymidine continues to decrease exponentially for at least 18 weeks after thymidine kinase deficiency and complete resistance to BrdUrd have been established. These phenotypic modifications are continuous or multistep in character; by clonal analysis they are found to occur in most, if not all, cells maintained in the presence of BrdUrd. Populations in transition thus come to be complex mosaics of different phenotypes that are comparatively stable if isolated in drug-free medium. The progressive evolution of cells resistant to BrdUrd will require new models for an underlying explanation.

Animals↗
PubMed2001

Evidence for the evolution of multiple genomes in arbuscular mycorrhizal fungi.

Ancient asexuals directly contradict the evolutionary theories that explain why organisms should evolve a sexual life history. The mutualistic, arbuscular mycorrhizal fungi are thought to have been asexual for approximately 400 million years. In the absence of sex, highly divergent descendants of formerly allelic nucleotide sequences are thought to evolve in a genome. In mycorrhizal fungi, where individual offspring receive hundreds of nuclei from the parent, it has been hypothesized that a population of genetically different nuclei should evolve within one individual. Here we use DNA-DNA fluorescent in situ hybridization to show that genetically different nuclei co-exist in individual arbuscular mycorrhizal fungi. We also show that the population genetics techniques used in other organisms are unsuitable for detecting recombination because the assumptions and underlying processes do not fit the fungal genomic structure shown here. Instead we used a phylogenetic approach to show that the within-individual genetic variation that occurs in arbuscular mycorrhizal fungi probably evolved through accumulation of mutations in an essentially clonal genome, with some infrequent recombination events. We conclude that mycorrhizal fungi have evolved to be multi-genomic.

Cell Nucleus↗
PubMed2003

Understanding the pathogenesis of myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are clonal disorders of an immature hematopoietic progenitor cell. MDS hematopoiesis is characterized by abnormal progenitor proliferation and impaired cellular differentiation and maturation. As a consequence, the majority of MDS patients have a gradual evolution towards progressive bone marrow failure and/or leukemic transformation. The efforts made by several research groups during the last few years have helped to unravel the complex underlying pathogenesis of MDS. In this review, we will focus on the principal cytogenetic and molecular abnormalities involved in MDS initiation and disease progression. Additionally, we will discuss the influence of the marrow microenvironment on survival and proliferation of hematopoietic progenitors in MDS.

Cell Transformation, Neoplastic↗
PubMed2005

Single-nucleotide polymorphism-based population genetic analysis of Mycobacterium tuberculosis strains from 4 geographic sites.

We studied genetic relationships among 5069 Mycobacterium tuberculosis strains recovered from patients enrolled in 4 population-based studies in the United States and Europe, by analysis of 36 synonymous single-nucleotide polymorphisms (SNPs). All strains were assigned to 1 of 9 major genetic clusters based on sSNP profile. The same 9 genetic clusters were revealed by analysis of 227 nonsynonymous SNPs, 121 intergenic SNPs, and concatenated profiles of 578 SNPs available for a subset of 48 representative strains. IS6110 profiles, spoligotypes, and mycobacterial interspersed repetitive unit patterns were nonrandomly associated with SNP-based phylogenetic lineages, together indicating a strongly clonal population structure. Isolates of the 9 genetic clusters were not distributed with equal frequency in all localities, reflecting geographic subdivision. The SNP-based phylogenetic framework provides new insight into the worldwide evolution of M. tuberculosis and a gateway for investigating genotype-disease phenotype relationships in large samples of strains.

Bacterial Typing Techniques↗
PubMed2006

The greater than twofold cost of integration for retroviruses.

Sexual reproduction, typically conceived of as a puzzling feature of eukaryotes, has posed an extraordinary evolutionary challenge in terms of the twofold replicative advantage of asexual over sexual organisms. Here we show mathematically that a greater than twofold cost is paid by retroviruses such as HIV during reverse transcription. For a retrovirus, replication is achieved through RNA reverse transcription and the effectively linear growth processes of DNA transcription during gene expression. Retroviruses are unique among viruses in that they show an alternation of generations between a diploid free living phase and a haploid integrated phase. Retroviruses engage in extensive recombination during the synthesis of the haploid DNA provirus. Whereas reverse transcription generates large amounts of sequence variation, DNA transcription is a high-fidelity process. Retroviruses come under strong selection pressures from immune systems to generate escape mutants, and reverse transcription into the haploid DNA phase serves to generate diversity followed by a phase of transcriptional clonal expansion during the restoration of diploidy from a stable, long lived, DNA encoded provirus.

Animals↗
PubMed1987

Myelodysplastic syndromes: evolution of overt leukaemia by one or several steps of transformation.

The evolution of leukaemia was studied prospectively in 29 patients with myelodysplastic syndrome (MDS) followed for 2-6 years by sequential blast counts, cell kinetics derived from quantitative 14C-autoradiography and karyotype analysis. Overt leukaemia developed in seven patients. Two distinct patterns of leukaemic evolution were identified. The first was characterized by a gradual increase in blast cell count and in the frequency of labelled blasts, and a corresponding reduction in myeloid maturation index indicating increased intracompartmental myeloblast divisions and premature myeloid cell death. A second pattern of leukaemic evolution was marked by a sudden rise in the blast cell population in a previously stable MDS. This rise was attributed both to an increased rate of blast proliferation, and the accumulation of non-proliferating blasts. In an additional patient with smouldering ANLL and multiple karyotype abnormalities, transient clinical remission took place following prednisone and oxymetholone therapy, characterized by a sideroblastic morphology, normal karyotype, and persistence of a highly abnormal myeloid maturation index. The sudden emergence of overt leukaemia in previously stable MDS in some of our patients and the temporary reversal of overt leukaemia into sideroblastic anaemia in one case, lend support to the notion of leukaemic evolution by several steps of transformation. On the other hand, the gradual transition of MDS into overt leukaemia in other patients is compatible with a single step leukaemia transformation, although the possibility of clonal disease prior to the development of MDS cannot be excluded with certainty.

Aged↗
PubMed2000

Occurrence of angioimmunoblastic T cell lymphoma in a patient with chronic myelomonocytic leukemia features.

In a patient with recently diagnosed chronic myelomonocytic leukemia features, the biopsy of a peripheral lymphadenopathy seven months later revealed disorganised lymphoid tissue with a few large EBER (+) LMP1 (+) B-lymphocytes before any treatment was given. At this time, a clonal TCR gamma rearrangement and very faint clonal IgH rearrangement were demonstrated, and the diagnosis of angioimmunoblastic T-cell lymphoma was made. Treatment with MOPP was started, followed by Hydroxycarbamide and CHOP but the outcome was fatal. During the evolution, there was no blastic transformation of the chronic myelomonocytic leukemia. The T-cell lymphoma extended to abdominal lymph nodes, Waldeyer ring and bone marrow and the percentage of large LMPI EBER (+) B-cells increased in the lymph nodes. These findings do not support a common stem cell abnormality leading to myelodysplasia in the bone marrow and lymphoma in peripheral lymph nodes. The lack of a clearcut light chain restriction in the EBV infected B-cell is suggestive of a persistant EBV infection in polyclonal or oligoclonal activated B-cells as described in immunodepressed patients. The association of CMML features and an angioimmunoblastic T-cell lymphoma is discussed.

B-Lymphocytes↗
PubMed1984

Toward the use of monoclonal antibodies in the analysis of tumor progression and cellular heterogeneity of human breast cancer.

Most, if not all human tumors have a clonal derivation. However, during the expansion of a tumor cell clone secondary genetic changes are continuously generated (tumor progression) leading to phenotypic heterogeneity. This cellular heterogeneity appears to be the basis for the evolution of a metastatic behaviour and resistance to chemo- and radiotherapy. Using conventional histopathology only a very limited information is obtained concerning this heterogeneity but in the case of human breast cancer additional knowledge is provided by analyses of cellular DNA content and estrogen and progesteron receptors. During the last few years a very impressing progress has been made in attempts to raise monoclonal antibodies against breast cancer using the hybridoma technique. A number of diagnostically and perhaps therapeutically useful antibodies are already available. It is therefore anticipated that within the next few years a panel of anti-breast cancer antibodies will be made available which will be able to define cellular heterogeneity and identify prognostically important tumor cell markers.

Animals↗
PubMed2004

Chromosomal instability and marker chromosome evolution in oral squamous cell carcinoma.

Squamous cell carcinoma of the head and neck and its subset, oral squamous cell carcinoma (OSCC), arise through a multistep process of genetic alterations as a result of exposure to environmental agents, such as tobacco smoke, alcoholic beverages, and viruses, including human papillomavirus. We and others have shown that the karyotypes of OSCC are near-triploid and contain multiple structural and numerical abnormalities. However, despite a background of clonal chromosomal aberrations, individual cells within a culture express many nonclonal numerical and structural abnormalities, termed chromosomal instability (CIN). To evaluate CIN in oral cancer cells, we isolated clones from two OSCC cell lines and carried out classical cytogenetic analysis, fluorescence in situ hybridization using centromere-specific probes, and spectral karyotyping. We observed variation in chromosome number within clones and between clones of the same cell line. Although similar numbers of centromeric signals for a particular chromosome were present, "homologs" of a chromosome varied structurally from cell to cell (marker chromosome evolution) as documented by classical and spectral karyotyping. In addition to the numerical chromosome variations within a clone, we observed marker chromosome evolution by structural chromosome alterations. It appears that both intrinsic structural alterations and extrinsic cytoskeletal factors influence chromosome segregation, resulting in individual tumor cells that express unique karyotypes. We show that CIN and marker chromosome evolution are essential acquired features of neoplastic cells. Proliferation of this heterogeneous cell population may provide some cells with the ability to evade standard therapies.

Biomarkers↗