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Results for “clonal analysis”

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At least 775 records · Page 43Linked to original sources
PubMed2001

Clonal hemopoiesis and risk of thrombosis in young female patients with essential thrombocythemia.

OBJECTIVE: Several studies demonstrated a high prevalence of nonrandom X-chromosome inactivation pattern (X-CIP) in essential thrombocythemia (ET). This study explored the incidence of clonal hemopoiesis in myeloid precursors and endogenous erythroid colonies (EECs) in ET patients and its correlation with thrombotic manifestations. MATERIALS AND METHODS: Clonal analysis of hemopoiesis using X-CIP was performed in 40 female patients with ET. Median age was 40.5 years (range 20-64), and median platelet count at testing time was 700 x 10(9)/L (range 220-1300 x 10(9)/L). Patients older than 65 years were excluded to reduce age-related skewing. Clonality was assessed on neutrophils, platelets, EECs, and bone marrow CD34(+) cells. RESULTS: Eight (20%) of 40 patients developed thrombosis mainly at diagnosis. Clonal hemopoiesis was found in 17 (42.5%) patients, 15 (37.5%) had polyclonal hemopoiesis, and 8 (20%) were considered uninterpretable due to constitutive skewing. Clonality was confirmed on purified CD34(+) subpopulations from bone marrow, documenting that clonality does not appear lineage-restricted. There were no statistical differences in age at diagnosis, median platelet count at testing time, and length of follow-up. Thrombotic episodes were significantly more frequent in the monoclonal group (p = 0.04, Fisher exact test). CONCLUSIONS: Young female patients with ET exhibiting a clonal pattern of hemopoiesis by X-CIP analysis are at higher risk for thrombosis. X-CIP analysis may contribute to defining the individual risk leading to appropriate treatment. X-CIP will allow a correct diagnosis in patients with latent myeloproliferative disorders and thrombosis in unusual sites. Clonal hemopoiesis is easily recognized by X-CIP, but its applicability is limited to the female sex and is hampered by the presence of age-related or constitutive skewing.

Adult↗
PubMed2001

The domino gene of Drosophila encodes novel members of the SWI2/SNF2 family of DNA-dependent ATPases, which contribute to the silencing of homeotic genes.

The Drosophila domino gene has been isolated in a screen for mutations that cause hematopoietic disorders. Generation and analysis of loss-of-function domino alleles show that the phenotypes are typical for proliferation gene mutations. Clonal analysis demonstrates that domino is necessary for cell viability and proliferation, as well as for oogenesis. domino encodes two protein isoforms of 3202 and 2498 amino acids, which contain a common N-terminal region but divergent C termini. The common region includes a 500 amino acid DNA-dependent ATPase domain of the SWI2/SNF2 family of proteins, which function via interaction with chromatin. We show that, although domino alleles do not exhibit homeotic phenotypes by themselves, domino mutations enhance Polycomb group mutations and counteract Trithorax group effects. The Domino proteins are present in large complexes in embryo extracts, and one isoform binds to a number of discrete sites on larval polytene chromosomes. Altogether, the data lead us to propose that domino acts as a repressor by interfering with chromatin structure. This activity is likely to be performed as a subunit of a chromatin-remodeling complex.

Adenosine Triphosphatases↗
PubMedDate not supplied

The ultrastructure of fresh and cultured cells in fifteen soft tissue and bone tumors.

Cultured cells from 15 soft tissue and bone tumors and surgical specimens from 14 of these were studied by electron microscopy. The cells, cultured for one to five weeks, maintained ultrastructural features similar to those found in the fresh tumor tissue. The ultrastructural characteristics of the cultured cells were distinct enough for diagnostic purposes. Short-term cultures from all tumors were subjected to cytogenetic analysis. Clonal chromosome aberrations were found in 11 of the tumors and normal karyotypes in the remaining four. Ultrastructural analysis of cultured cells can be used for cell type identification and tumor classification.

Adolescent↗
PubMed1994

T cell clones expressing the natural killer cell-related p58 receptor molecule display heterogeneity in phenotypic properties and p58 function.

A new anti-p58 monoclonal antibody (mAb), termed CH-L, has been used to characterize a minor subset of T lymphocytes co-expressing p58 and CD3 molecules. In two-color immunofluorescence analysis, CH-L+CD3+ cells represented 0.5 to 6% of the peripheral blood lymphocytes (in 20 healthy donors). Clonal analysis showed that most CD3+CH-L+ T cell clones expressed the CD8+4- T cell receptor (TcR) alpha/beta+ phenotype, while only a few were CD8-4+ TcR alpha/beta, CD8-4- TcR alpha/beta+ or CD8-4- TcR gamma/delta+. Western blot analysis indicated that the CH-L mAb identifies the same 56-58-kDa diffuse band in both T and natural killer cell (NK) clones. A minority of T cell clones also expressed other NK-related markers such as CD16, CD56 and CD94 and two clones also reacted with the anti-p58 mAb EB6. Interestingly, most clones displayed cytolytic activity in an anti-CD3 mAb-triggered redirected killing assay against the Fc gamma receptor+ P815 target cells and NK-like activity against K562 and Raji cells. In contrast, the IGROV-1 ovarian carcinoma cell line was resistant to cytolysis by all of these clones. Since p58 molecules have previously been shown to exert regulatory functions on NK-mediated lysis, we investigated whether anti-p58 mAb could also influence cytotoxicity mediated by CD3+p58+ T lymphocytes. Lysis of P815 target cells, triggered by anti-CD3 mAb, could be inhibited by anti-p58 mAb in 8 out of 12 cytolytic clones tested, while 4 clones were not inhibited. In addition, anti-p58 mAb enhanced the cytolytic activity of 3 clones against IGROV-1 and of 4 other clones against Raji target cells. Taken together, these data indicate that p58+ T cells express heterogeneous phenotypes and different forms of TcR and, in most instances, display cytolytic functions. Perhaps more importantly, the p58 molecule appears to modulate the cytolytic activity triggered via the CD3/TcR complex.

Antigens, Differentiation, T-Lymphocyte↗
PubMed2006

BMP2 and BMP6 control p57(Kip2) expression and cell growth arrest/terminal differentiation in normal primary human epidermal keratinocytes.

Functional studies of the canonical Bone Morphogenetic Protein (BMP) signalling pathway in human epidermal keratinocytes have been limited to the immortalized and p53-mutated HaCaT cells and are primarily dependent on BMP6 treatment in mouse epidermal keratinocytes. Despite these insightful analyses, the molecular mechanism underlying the role of BMP signalling in the precise balance between growth arrest and terminal differentiation of keratinocytes still remains not clearly defined. The current study first investigated the hitherto uncharacterized status and functions of BMP signalling in normal human keratinocytes by using three independent strains of primary interfollicular epidermal keratinocytes. Then we provided data demonstrating the role of BMP2 compared to BMP6 in the inhibition of growth and induction of subsequent terminal differentiation of these cells. A second relevant finding is based on the clonal analysis of colony types present in untreated and BMP2/6-treated cultures in absence of EGF. BMP treatment results in the clonal transition from proliferative to abortive colonies, suggesting that BMP signalling most likely inhibits stem cell proliferation and triggers cell cycle exit from transit amplifying cells. Third, we showed evidence that, of the three members of the Cip/Kip family of cyclin-dependent kinase inhibitors, only p57(Kip2) and p21(Cip1) have a BMP2/6-induced expression. One mechanism of inhibition of cell proliferation involves p57(Kip2) as an immediate early response, in contradistinction with p21(Cip1) which largely depends on de novo protein synthesis for its effect to proceed. All together, these results clarify the BMP signalling status in normal primary human keratinocytes and support a new mechanism of inhibition of the proliferation of interfollicular epidermal keratinocytes coupled with induction of their terminal differentiation following BMP2 or BMP6 addition.

Biomarkers↗
PubMed1992

Assessment of X-chromosome inactivation patterns using the hypervariable probe M27 beta in normal hemopoietic cells and acute myeloid leukemic blasts.

The value of the hypervariable X-linked probe M27 beta for use in the analysis of X-chromosome inactivation patterns in normal blood and bone marrow cells and in the assessment of clonality in acute myeloid leukemia (AML) blast cells has been determined. By electrophoresing samples for 30 h, heterozygosity of the M27 beta locus was demonstrable in 324/415 females (78%) and this value could be increased to 93% by electrophoresing for 50 h. Determination of the X-chromosome inactivation patterns in blood and bone marrow samples from hematologically normal females was possible in approximately 90% of heterozygous individuals. The X-chromosome inactivation ratios obtained with M27 beta were comparable with phosphoglycerate kinase or hypoxanthine phosphoribosyl transferase in 46 individuals heterozygous for one of these genes in addition to M27 beta. The results obtained were closely correlated (r = 0.89). In 21 of 35 (60%) AML blasts, however, there was hypermethylation of the M27 beta locus and clonal analysis was not possible. Hypermethylation was not related to FAB type.

Bone Marrow Cells↗
PubMed2002

Clonally unrelated Hodgkin's disease following autologous stem cell transplant for B-cell lymphoma.

Lymphoproliferative disorders after autologous stem cell transplantation (SCT) are rare. We describe two cases of Hodgkin's disease (HD) as a late secondary neoplasia following autologous SCT for mantle cell lymphoma and B-cell chronic lymphocytic leukaemia respectively. Both HD cases were of mixed cellularity type, showed Epstein-Barr virus (EBV) positivity and followed an aggressive course. Clonal analysis of rearranged immunoglobulin genes from the primary B-cell neoplasm and the secondary HD provided evidence of separate clonal origins of the two tumours in both patients, thus excluding secondary transformation of the original B-cell clone through EBV as the causative event for development of HD.

Gene Rearrangement, B-Lymphocyte, Heavy Chain↗
PubMed2001

Profiling clonality and progression in multiple premalignant and malignant oral lesions identifies a subgroup of cases with a distinct presentation of squamous cell carcinoma.

A cohort of head and neck cancer patients, without exposure to tobacco and alcohol, presented with multiple preneoplastic and neoplastic lesions, the natural history of which may span several decades. Examination of these cases provides an opportunity to study the relationship between genetic, morphological, and clonal progression in these fields and establish whether they represent a unique presentation of squamous cell carcinoma. The presence of a common novel microsatellite allele, a common breakpoint or concordant allelic imbalance at multiple loci, reveals that a high proportion of these serial lesions arise due to spread of a precursor. The tumors arising in these patients were typically nonaggressive, although metastases developed at a late stage, supporting the notion that the genotype results in a phenotype with a propensity for lateral spread, rather than invasion. Different genetic aberrations were detected in morphologically similar phenotypes such that no consistent early or late events were associated with development of premalignant lesions. Combining information about the clinicopathological features and histological examination of the margins with that derived from clonality analysis reveals that a subgroup of patients, without exposure to the traditional risk factors associated with this disease, developed multiple clonally related oral lesions and represents a unique presentation of head and neck squamous cell carcinoma. We suggest the term clonal cancerization to describe multiple premalignant and malignant lesions when there is conclusive evidence that they arise due to lateral spread from a common precursor.

Adult↗
PubMed2004

Hypereosinophilic syndrome and cyclic oscillations in blood cell counts. A clonal disorder of hematopoiesis originating in a pluripotent stem cell.

We studied a patient with hypereosinophilic syndrome (HES) who had myeloproliferative features, was unresponsive to imatinib mesylate, and showed cyclic oscillations in blood cell counts. No rearrangement in PDGFRA, PDGFRB and ETV6 genes was detected. Clonal analysis of hematopoiesis consistently showed skewed X-chromosome inactivation patterns in both granulocytes and T-lymphocytes, indicating a clonal myeloproliferative disorder originating in a pluripotent stem cell.

Adult↗
PubMed2003

The identification of monoclonality in fibrous dysplasia by methylation-specific polymerase chain reaction for the human androgen receptor gene.

The nature of fibrous dysplasia, a well-known and relatively common bone lesion, is controversial. We report here the first polymerase chain reaction (PCR)-based clonality analysis of fibrous dysplasia in which 11 cases obtained from females with a polymorphism at the human androgen receptor gene locus ( HUMARA) were examined using a methylation-specific PCR procedure. This assay allowed accurate evaluation of the clonality status of this disease by eliminating restriction enzyme digestion that had been used previously in conventional HUMARA analysis. Eight samples proved to be informative for the assay, and they all showed non-random X-chromosome inactivation, indicative of a monoclonal pattern. These findings demonstrate a clonal origin for fibrous dysplasia, suggesting that the disease is a neoplastic lesion rather than a "dysplastic" process, as has been generally believed.

Adolescent↗
PubMed2000

The shut-down gene of Drosophila melanogaster encodes a novel FK506-binding protein essential for the formation of germline cysts during oogenesis.

In Drosophila melanogaster, the process of oogenesis is initiated with the asymmetric division of a germline stem cell. This division results in the self-renewal of the stem cell and the generation of a daughter cell that undergoes four successive mitotic divisions to produce a germline cyst of 16 cells. Here, we show that shut-down is essential for the normal function of the germline stem cells. Analysis of weak loss-of-function alleles confirms that shut-down is also required at later stages of oogenesis. Clonal analysis indicates that shut-down functions autonomously in the germline. Using a positional cloning approach, we have isolated the shut-down gene. Consistent with its function, the RNA and protein are strongly expressed in the germline stem cells and in 16-cell cysts. The RNA is also present in the germ cells throughout embryogenesis. shut-down encodes a novel Drosophila protein similar to the heat-shock protein-binding immunophilins. Like immunophilins, Shut-down contains an FK506-binding protein domain and a tetratricopeptide repeat. In plants, high-molecular-weight immunophilins have been shown to regulate cell divisions in the root meristem in response to extracellular signals. Our results suggest that shut-down may regulate germ cell divisions in the germarium.

Alleles↗
PubMed2005

Evidence from the stop-EGFP mouse supports a niche-sharing model of epidermal proliferative units.

The classical model of epidermal proliferative units (EPUs) postulates that each EPU is composed of a single column of corneocytes plus epidermal cells directly below the column and is maintained by a single stem cell within the unit. Using the stop-enhanced green fluorescent protein (stop-EGFP) transgenic mouse system, we previously showed epidermal stem cell clonal lineages could produce multiple adjacent corneocytes (i.e. epidermal cells belonging to multiple adjacent EPUs), contradicting the classical EPU model. One possible problem with our earlier study was that N-ethyl-N-nitrosourea (ENU) was used to generate mutations for clonal analysis. This could alter the normal environment of the epidermal tissue and might lead to an artificial expansion of stem cell clonal lineages. In this study, we replicate our earlier findings using untreated stop-EGFP mice and relying on spontaneous mutations to generate clonal cell lineages. We propose an alternative to the classical EPU model to explain the dynamic nature of epidermal proliferation. Our niche-sharing model of EPUs allows epidermal cells to horizontally migrate among EPUs, so that multiple stem cells cooperatively maintain a larger proliferative compartment.

Animals↗
PubMed2003

['Reverse' variant of follicular lymphoma with monoclonality of the immunoglobulin heavy chain and T cell receptor gamma chain genes].

We report an unusual case of the 'reverse' variant of follicular lymphoma in which the nodules had central parts that stained dark and cuffs that stained pale. Because diagnosis was difficult relying only on formalin-fixed histopathology, we examined the cell surface markers and karyotype. The patient, a 65-year-old man, presented with multiple lymphadenopathy, low-grade fever, night sweats, anorexia, dry cough and sense of chest oppression. Cell surface marker analysis showed that pathologic lymphocytes were positive for CD 10, CD 19, CD 20, HLA-DR, IgM/IgD and kappa, and t (14; 18) (q 32; q 21) was detected by karyotypic analysis. The 'reverse' variant of follicular lymphoma, clinical stage IVB was diagnosed the rearrangement band was detected with PCR-based clonality analysis in not only the immunoglobulin heavy chain gene but also the T cell receptor gamma chain gene, thus confirming monoclonal proliferation of both B cells and T cells.

Aged↗
PubMed1999

Clonal evolution as judged by immunoglobulin heavy chain gene rearrangements in relapsing precursor-B acute lymphoblastic leukemia.

Oligoclonality and ongoing clonal evolution are common features in patients with precursor-B (pre-B) acute lymphoblastic leukemia (ALL), as judged by immunoglobulin heavy chain (IgH) gene rearrangement analysis. These features are considered to be results of secondary rearrangements after malignant transformation or emergence of new tumor clones. In the present study we analyzed the IgH gene rearrangement status in 18 cases with relapsing pre-B ALL using variable heavy chain (V(H)) gene family specific polymerase chain reaction (PCR) amplification and single stranded conformation polymorphism (SSCP) analysis. Clonal IgH rearrangements were displayed in all leukemias but one, and altered rearrangement patterns occurred in five cases (29%), which were selected for detailed nucleotide sequence analysis. In one case, multiple subclones at diagnosis were suggested to be derived from a progenitor clone through joining of different V(H) germline gene segments to a pre-existing D-J(H) complex (V(H) to D-J(H) joining). Evidence for V(H) gene replacement with identical N-sequences at the V(H)-D junction and a common D-J(H) region was observed in one case. Diversification at the V(H)-D junction consisting of heterogeneous N-sequences were observed in one case. This molecular modification of the V(H)-D region could fit a hypothesized "open-and-shut" mechanism. Nevertheless, despite these ongoing events at least one IgH rearrangement remained unchanged throughout the disease in most patients, indicating that the immunoglobulin heavy chain locus can be a suitable marker for detection of minimal residual disease (MRD).

Base Sequence↗
PubMed2002

Clinical and biological significance of clonal macrophage detection in hemophagocytic syndrome.

By using the method of clonal analysis the evidence to prove that Hemophagocytic syndrome (HPS) is reactive or malignant was investigated to probe into the pathogenesis of HPS and its relations with clinical prognosis. The macrophages abnormally proliferated in bone marrow were isolated. Electrophoresis analysis was made after DNA extraction, enzyme restriction of human ardrogen receptor (HUMARA) genetic locus, and PCR amplification. In the 9 specimens, clonal proliferation was found in 2 cases and nonclonal proliferation in 7. Among the 7 cases of nonclonal proliferation, 3 were voluntarily discharged without clinical outcome, 2 cases fully recovered after 2-3 week treatment of large dose gamma globulin intravenous drip and hormone therapy, 1 case died at the 43th day after the hormone and anti-infection therapy, and one case was found to have granular leukoblast in peripheral blood after 3 weeks and diagnosed as having M2a after bone puncture. For the two patients with clonal proliferation, one obtained remission after chemotherapy and the other was died after 32 days without chemotherapy. It was concluded that there do exist clonal or malignant proliferation in HPS, so not every case is reactive.

Child↗
PubMed2004

Gbb/Bmp signaling is essential for maintaining germline stem cells and for repressing bam transcription in the Drosophila testis.

Stem cells are responsible for replacing damaged or dying cells in various adult tissues throughout a lifetime. They possess great potential for future regenerative medicine and gene therapy. However, the mechanisms governing stem cell regulation are poorly understood. Germline stem cells (GSCs) in the Drosophila testis have been shown to reside in niches, and thus these represent an excellent system for studying relationships between niches and stem cells. Here we show that Bmp signals from somatic cells are essential for maintaining GSCs in the Drosophila testis. Somatic cyst cells and hub cells express two Bmp molecules, Gbb and Dpp. Our genetic analysis indicates that gbb functions cooperatively with dpp to maintain male GSCs, although gbb alone is essential for GSC maintenance. Furthermore, mutant clonal analysis shows that Bmp signals directly act on GSCs and control their maintenance. In GSCs defective in Bmp signaling, expression of bam is upregulated, whereas forced bam expression in GSCs causes the GSCs to be lost. This study demonstrates that Bmp signals from the somatic cells maintain GSCs, at least in part, by repressing bam expression in the Drosophila testis. dpp signaling is known to be essential for maintaining GSCs in the Drosophila ovary. This study further suggests that both Drosophila male and female GSCs use Bmp signals to maintain GSCs.

Activin Receptors, Type II↗
PubMed2001

Characterization of the T-cell repertoire in autologous graft-versus-host disease (GVHD): evidence for the involvement of antigen-driven T-cell response in the development of autologous GVHD.

Administration of cyclosporine A (CsA) after autologous stem cell transplantation elicits an autoimmune syndrome with pathology similar to graft-versus-host disease (GVHD). This syndrome, termed autologous GVHD, is associated with the appearance of autoreactive T cells directed at major histocompatibility class (MHC) class II antigens. In the rat model of autologous GVHD, clonal analysis reveals that the effector T cells are highly conserved and recognize a peptide from the invariant chain peptide presented by MHC class II. Although human autologous GVHD effector T cells share a similar phenotypic specificity, clonality of the response in humans has not been determined. To examine the human effector T-cell response, the T-cell repertoire of peripheral blood lymphocytes was assessed by complementarity-determining region 3 (CDR3) size distribution analysis and T-cell clonotype analysis in 26 patients treated with CsA after transplantation. Autologous GVHD developed in 3 of 4 patients with human leukocyte antigen (HLA)-DRB1*0701, and clonal expansions of beta-chain variable region (BV)16(+) T cells were shared. Clonal expansions within BV15(+) and BV22(+) T cells were also detected in 4 of 6 patients with HLA-DRB1*1501 and in 3 of 4 patients with HLA-DRB1*0401, respectively. Sequencing of BV16 cDNA for which the CDR3 size pattern exhibited apparent clone predominance revealed an identical CDR3 peptide sequence in 2 different patients, one with HLA-DRB1*0701 and the other with HLA-DRB1*1502. These findings indicate that the discrete antigen-driven expansion of T cells is involved in autologous GVHD. (Blood. 2001;98:868-876)

Adult↗
PubMed1995

Cell lineage and patterns of migration in the developing cortex.

Knowledge of cell lineage in the cortex is important for understanding normal development as well as brain malformations. We studied cell lineage in rats by injecting a library of up to 3400 retroviruses, distinguishable by PCR analysis and encoding alkaline phosphatase, at E14-19. Histological analysis at P15 revealed normal cell morphology and allowed identification of about 80% of all labelled cells. PCR amplification of DNA tags allowed clonal analysis. Cortical cells labelled at E15 formed clustered or widespread clones with equal frequency. Clustered clones contained one to four cells within about 1 mm that had similar morphology and laminar location. However, 48% of cortical clones contained multiple cell types with widely different locations (2.1-6.7 mm; mean, 3.8 mm). Widespread clones contained two to four 'subunits' (one to five neurons each), spaced at apparent intervals of 2-3 mm, with each subunit morphologically indistinguishable from a clustered clone. Distinct subunits in the same clone usually differed in laminar location suggesting sequential formation. Clones labelled at E17 contained fewer neurons and up to two subunits. Clustered clones seem to be produced by stationary progenitors, whereas progenitors of clusters may themselves be produced by migratory, multipotential cells.

Animals↗