Detection and follow-up of fibroblast growth factor receptor 3 expression on bone marrow and circulating plasma cells by flow cytometry in patients with t(4;14) multiple myeloma.

The t(4;14)(p16;q32) translocation, found in 15% of multiple myeloma (MM) cases, indicates a poor prognosis. Plasma cells (PC) with t(4;14) ectopically express the fibroblast growth factor receptor 3 (FGFR3) tyrosine kinase receptor, which has potential transforming activity and may represent a therapeutic target. To detect FGFR3 protein expression, bone marrow (BM) aspirate from 200 consecutive newly diagnosed (n = 116) or relapsing (n = 74) MM patients was studied by flow cytometry (FC) using anti-CD138 and anti-FGFR3 antibodies. FC data was compared to real time quantitative-polymerase chain reaction (RQ-PCR) of the IGH-MMSET and FGFR3 transcripts. An IGH-MMSET transcript was found in 24/200 patients (12%). In 20 of these, FC detected CD138(+)/FGFR3(+) cells. No expression of FGFR3 was detected in the 4 FGFR3(-) cases by RQ-PCR. FGFR3 was never expressed on PC without t(4;14). Circulating PC (CPC) were detected in patients with (11/11) and patients without (13/41) t(4;14). In 2/8 t(4;14) cases studied longitudinally, coexisting FGFR3(+) and FGFR3(-) CPC were observed. Fluorescent in situ hybridisation (FISH) analysis of the FGFR3(-) subclones showed deletion of the der(14) in one patient. In conclusion, as a supplemental method to RQ-PCR or FISH, FC analysis of FGFR3 expression is a reliable and routinely available method for the detection and management of new therapeutic approaches of t(4;14) MM.

[Perioperative complications after heart valve replacement]. / Perioperative Komplikationen nach Herzklappenersatz.

These days, the majority of perioperative complications resulting from operations on heart valves are more a consequence of the increasing age and morbidity of the patients and, despite all cardiac surgical and intensive care innovations, are still more the effect of the procedure on the other organ systems of the patient than being purely of a surgical nature. The surgical short- and long-term results after heart valve operations are significantly influenced by the early detection and adequate management of these manifold complications.

[Perioperative complications after heart valve replacement]. / Perioperative Komplikationen nach Herzklappenersatz.

These days, the majority of perioperative complications resulting from operations on heart valves are more a consequence of the increasing age and morbidity of the patients and, despite all cardiac surgical and intensive care innovations, are still more the effect of the procedure on the other organ systems of the patient than being purely of a surgical nature. The surgical short - and long-term results after heart valve operations are significantly influenced by the early detection and adequate management of these manifold complications.

Characterization of hematopoietic lineage-specific gene expression by ES cell in vitro differentiation induction system.

The continuous generation of mature blood cells from hematopoietic progenitor cells requires a highly complex series of molecular events. To examine lineage-specific gene expression during the differentiation process, we developed a novel method combining LacZ reporter gene analysis with in vitro hematopoietic differentiation induction from mouse embryonic stem cells. For a model system using this method, we chose the erythroid and megakaryocytic differentiation pathways. Although erythroid and megakaryocytic cells possess distinct functional and morphologic features, these 2 lineages originate from bipotential erythro-megakaryocytic progenitors and share common lineage-restricted transcription factors. A portion of the 5' flanking region of the human glycoprotein IIb (alphaIIb) integrin gene extending from base -598 to base +33 was examined in detail. As reported previously, this region is sufficient for megakaryocyte-specific gene expression. However, previous reports that used human erythro-megakaryocytic cell lines suggested that one or more negative regulatory regions were necessary for megakaryocyte-specific gene expression. Our data clearly showed that an approximately 200-base enhancer region extending from -598 to -400 was sufficient for megakaryocyte-specific gene expression. This experimental system has advantages over those using erythro-megakaryocytic cell lines because it recapitulates normal hematopoietic cell development and differentiation. Furthermore, this system is more efficient than transgenic analysis and can easily examine gene expression with null mutations of specific genes.

Accessibility control of variable region gene assembly during T-cell development.

T-cell development is a complex and ordered process that is regulated in part by the progressive assembly and expression of antigen receptor genes. T cells can be divided into two lineages based on expression of either an alpha beta or gamma delta T-cell antigen receptor (TCR). The genes that encode the TCR beta and gamma chains lie in distinct loci, whereas the genes that encode the TCR alpha and delta chains lie in a single locus (TCR alpha/delta locus). Assembly of TCR variable region genes is mediated by a site-specific recombination process that is common among all lymphocytes. Despite the common nature of this process, recombination of TCR genes is tightly regulated within the context of the developing T cell. TCR beta, gamma and delta variable region genes are assembled prior to TCR alpha variable region genes. Furthermore, assembly of TCR beta variable region genes is regulated within the context of allelic exclusion. The regulation of rearrangement and expression of genes within the TCR alpha/delta locus presents a complicated problem. TCR alpha and delta variable region genes are assembled at different stages of T-cell development, and fully assembled TCR alpha and delta variable region genes must be expressed in distinct lineages of T cells, alpha beta and gamma delta, respectively. We have developed several experimental approaches to assess the role of cis-acting elements in regulating recombination and expression of TCR genes. Here we describe these approaches and discuss our analyses of the regulation of accessibility of the TCR beta and TCR alpha/delta loci during T-cell development.

Treatment of active gastroesophageal variceal bleeding with terlipressin or hemostatic balloon in patients with cirrhosis. A randomized controlled trial.

Gastroesophageal variceal bleeding due to portal hypertension should be treated by endoscopic sclerotherapy. This procedure, however, has some limitations. It has been established that vasoactive drugs are effective for controlling active variceal bleeding. We report the results of a randomized controlled trial comparing terlipressin to hemostatic tube (Linton-Michel tube) for the treatment of bleeding gastroesophageal varices in cirrhotic patients. Thirty-seven cirrhotic patients with a total of 40 episodes of gastroesophageal variceal bleeding were included in this trial. Patients were randomly assigned to intravenous terlipressin or Linton-Michel tube (LM tube), for 24 h. During this period, hemostasis was defined as obtaining of hemodynamic and hematocrit stabilization and/or absence of hematemesis or melena. Bleeding recurrence was assessed during a 1-month period after treatment. Twenty bleeding episodes were treated with terlipressin (Group I) and 20 with LM tube (Group II). Both groups of patients were similar in age, sex distribution, etiology of cirrhosis and degree of hepatic insufficiency. Bleeding was controlled in 70% of patients from Group I and in 95% from Group II (p < 0.05) during treatment. Bleeding recurred in 14% of patients in Group I vs. 36% in Group II 1 week following the treatment (p > 0.05) and in 16.6% in Group I vs. 83.3% in Group II 1 month after treatment (p < 0.05). Complications were more frequent in Group II than in Group I (65 vs. 15%, p < 0.05). Mortality rate was similar in both groups 1 month after treatment. In conclusion, hemostatic tubes were superior to terlipressin for the control of active gastroesophageal variceal bleeding within the first 24 h. Complications and bleeding recurrence were more frequent in patients treated by hemostatic tube within a period of 1 month after treatment. Mortality rate was similar in both groups of patients.

[Loss of a stent in the left main coronary artery and secondary migration into the left circumflex artery needing surgical extraction. Apropos of a case]. / Perte dans le tronc commun de la coronaire gauche d'une endoprothèse et migration secondaire dans l'artère circonflexe ayant conduit à une extraction chirurgicale. A propos d'un cas.

The authors report a case of accidental loss of a coronary stent in the coronary arteries and its migration into the circumflex artery. This complication occurred during revascularisation of the left anterior descending artery. In view of a dissection at the site of angioplasty and the migration of the stent, emergency surgery was undertaken comprising bypass grafting of the left anterior descending and arteriology of the left circumflex arteries to recover the stent. This is a rare complication, the frequency is probably underestimated. The authors discuss the factors predisposing to failure of implantation and the means of recovering the stents. The consequences of loss of a stent in the coronary or systemic circulations are also commented.

The CBFbeta subunit is essential for CBFalpha2 (AML1) function in vivo.

The CBFbeta subunit is the non-DNA-binding subunit of the heterodimeric core-binding factor (CBF). CBFbeta associates with DNA-binding CBFalpha subunits and increases their affinity for DNA. Genes encoding the CBFbeta subunit (CBFB) and one of the CBFalpha subunits (CBFA2, otherwise known as AML1) are the most frequent targets of chromosomal translocations in acute leukemias in humans. We and others previously demonstrated that homozygous disruption of the mouse Cbfa2 (AML1) gene results in embryonic lethality at midgestation due to hemorrhaging in the central nervous system and blocks fetal liver hematopoiesis. Here we demonstrate that homozygous mutation of the Cbfb gene results in the same phenotype. Our results demonstrate that the CBFbeta subunit is required for CBFalpha2 function in vivo.

Gene-targeted deletion and replacement mutations of the T-cell receptor beta-chain enhancer: the role of enhancer elements in controlling V(D)J recombination accessibility.

To assess the role of transcriptional enhancers in regulating accessibility of the T-cell receptor beta-chain (TCRbeta) locus, we generated embryonic stem cell lines in which a single allelic copy of the endogenous TCRbeta enhancer (Ebeta) was either deleted or replaced with the immunoglobulin heavy-chain intronic enhancer. We assayed the effects of these mutations on activation of the TCRbeta locus in normal T- and B-lineage cells by RAG-2 (recombination-activating gene 2)-deficient blastocyst complementation. We found that Ebeta is required for rearrangement and germ-line transcription of the TCRbeta locus in T-lineage cells. In the absence of Ebeta, the heavy-chain intronic enhancer partially supported joining region beta-chain rearrangement in T- but not in B-lineage cells. However, ability of the heavy-chain intronic enhancer to induce rearrangements was blocked by linkage to an expressed neomycin-resistance gene (neo(r)). These results demonstrate a critical role for Ebeta in promoting accessibility of the TCRbeta locus and suggest that additional negative elements may cooperate to further modulate this process.

Increased T-cell apoptosis and terminal B-cell differentiation induced by inactivation of the Ets-1 proto-oncogene.

The Ets-1 proto-oncogene is a member of a transcription factor family characterized by homology to the v-ets oncogene. In adult mice, Ets-1 is expressed predominantly in lymphoid cells where it has been implicated in regulating transcription of lymphocyte-specific genes. Following T-cell activation, the specific DNA binding activity of Ets-1 is inactivated by transient phosphorylation, suggesting a function in the transition from the resting to activated state. Ets-1 has also been suggested to cooperate with the AP-1 transcription factor complex to mediate cellular growth factor responses. Here we show, by using RAG-2-deficient blastocyst complementation, that Ets-1 deficiency has dramatic, but different, effects on development and function of T- and B-lineage cells. Ets-1-deficient T cells were present in reduced numbers and were highly susceptible to cell death in vitro. In contrast, Ets-1-deficient B cells were present in normal numbers but a large proportion were IgM plasma cells. Our data demonstrate that Ets-1 is essential for maintenance of the normal pool of resting T- and B-lineage cells.

Unexpected consistent involvement of V beta gene segments in inappropriate T-cell receptor beta gene rearrangements occurring in B-lineage acute lymphoblastic leukemias.

T-cell receptor beta (TCR beta) gene rearrangements occur in a third of early B-cell acute lymphoblastic leukemias (ALLs). V, D, and J segments involved in these inappropriate rearrangements remain unknown and are of interest, both because partial D beta J beta and complete V beta D beta J beta recombinations occur at distinct stages of thymic maturation and because these rearrangements are regulated differently. We have therefore studied in detail seven cases of B-lineage ALL that show inappropriate clonal TCR beta gene rearrangements. Analysis of genomic DNA by Southern hybridization with C beta, J beta 1, V beta 8, and V beta 11 probes suggested the involvement of V beta segment in tumor cell rearrangements. A complete genomic library constructed from one case was screened with a C beta probe, and the TCR beta gene rearrangement was cloned and fully sequenced to show an out of frame V beta 2.2-J beta 2.6 recombination. TCR beta gene rearrangements occurring in other cases were further analyzed by polymerase chain reaction (PCR) using J beta and V beta primers and the resulting specific PCR products were sequenced. Evidence of clonal V beta rearrangements was obtained in all cases. These unexpected findings represent the first definitive demonstration that complete V beta(D beta)J beta rearrangements can occur in B-lineage cells and contrast with the previously reported lack of V beta(D beta)J beta rearrangement in B cells from V beta-J beta-C beta-E mu transgenic mice. In the context of increasing evidence that rearrangements are linked to transcription of unrearranged gene segments, these data prompt a search in B-lineage ALL cells for the presence of germline V beta transcripts whose deregulated expression may be linked to early transforming events.

Expression of human recombination activating genes (RAG1 and RAG2) in neoplastic lymphoid cells: correlation with cell differentiation and antigen receptor expression.

Regulation of V-(D)-J recombinations that occur in antigen receptor encoding genes remains poorly understood. Recently, two genes, RAG1 and RAG2, that are able to activate rearrangement of synthetic recombination substrates were cloned in mouse and a human gene homologous to RAG1 was described. To define the differentiation stages corresponding to RAG1 and RAG2 RNA expression, we have studied a large number of B- and T-lymphoid neoplasias. First, we show that a human gene homologous to the murine RAG2 is transcribed in humans. Moreover, using a polymerase chain reaction approach, we have shown that RAG are expressed not only in T-cell receptor (TCR)-negative T-cell acute lymphoblastic leukemias (T-ALLs), but also in some cases in which a significant percentage of cells expressed surface TCR. Absence of RAG expression was shown in certain T-ALLs at variable stages of thymic differentiation. Data obtained in B-lineage ALLs show that RAG RNAs are expressed in almost all slg- B-lineage ALLs but are not transcribed in the slg+ B-cell proliferations tested, including Burkitt's ALLs, follicular center cell lymphomas, and chronic leukemias. These findings are consistent with the involvement of RAG in the control of in vivo V-(D)-J recombinations. These findings are also of interest in the delineation of potential regulatory factors acting on RAG transcription and in the understanding of the mechanisms of specific chromosomal abnormalities occurring in immature lymphoid cells.

Intracerebral stenosing arteriopathies. Contribution of three radiological techniques to the diagnosis.

Fifty-one patients with intracerebral stenosing arteriopathy were studied by computerized tomography (CT), magnetic resonance imaging (MRI) and cerebral arteriography. Clinical symptoms were varied, included impaired cognitive functions, progressive neurological deficit, headache and vomiting, and were sometimes not suggestives of the diagnosis. CT scans of the brain were normal in 25 percent of the cases or they were not probative because of various and non-specific abnormalities (hypodensity of various types or haemorrhagic hyperdensity). MRI always showed abnormalities but in many cases the lesions observed on T2-weighted images consisted of non-specific focal areas of high-intensity signal in the white matter. High-intensity signals in both white matter and cortex seemed to be more suggestive of the diagnosis. In this as in other studies, arteriography therefore remains the reference examination for stenosing arteriopathies. Inflammatory, infectious and atheromatous processes are the main causes of these arterial lesions. The aetiological value of radiological examinations is poor, and in most cases the morphology and distribution of the lesions does not point to any specific origin. However, herpes zoster arteritis usually affects the proximal segments of the anterior and middle cerebral arteries and spares the carotid siphon.

Recombination activating genes and CD3-TCR molecules are coexpressed in a subset of human T-cell acute lymphoblastic leukemias.

The V-(D) -J recombination that occurs during lymphoid differentiation is the basic event which settles the diversity of antigen receptors. Two recently cloned genes, RAG1 and RAG2, are sufficient to induce rearrangements of synthetic substrates when transfected into fibroblasts. In order to determine at which differentiation steps where the human RAG are expressed and in order to investigate the possible impairment of their expression by the leukemic process, we have recently studied a large series of B and T lymphoid neoplasias. We show that RAG are expressed in almost all sIg- B-ALL but not in the sIg+ B cell proliferations we have tested. Furthermore, we show that RAG can be expressed not only by CD3-TCR negative but also by CD3-TCRab or gd positive T-ALL cells. We conclude that the recombinase activity is not turned off by the expression of a functionnal T-cell receptor on the cell surface. This observation is in line with recent studies on RAG expression in human thymus and are of major interest to understand the set up of the TCR repertoire.

Detection of a T cell receptor delta chain with an anti-TCR alpha chain serum.

Two types of T cell antigen-specific receptors have been described. Most peripheral blood T lymphocytes express, at their surface, an antigen receptor consisting of alpha and beta subunits, while a small subset of thymocytes and a minority of mature T lymphocytes express a heterodimeric receptor termed gamma delta. Whereas the gene segments localization corresponding to the TCR gamma and beta chains are separate, genes encoding the joining and the constant regions of TCR delta chain are located between the TCR V alpha region and the J alpha-C alpha gene cluster. To determine whether V alpha gene segments are used by delta chains, immunoprecipitations from human TCR gamma delta expressing cell clones were performed with an anti-alpha serum. The results show that a rabbit antiserum raised against the purified REX TCR alpha subunit immunoprecipitates a TCR delta chain from the cell surface of only one human T cell clone termed SO1. However, since no SO1 RNA hybridization is observed with REX TCR V alpha probe and SO1 cloned cells do react with an anti-V delta 2 monoclonal antibody, we conclude that TCR delta and alpha chains expressed a limited structural homology and that REX TCR V alpha gene do not seem to be frequently used in a functional delta chain.

Regulation of transcription of the human T cell antigen receptor delta chain gene. A T lineage-specific enhancer element is located in the J delta 3-C delta intron.

We have defined transcriptional enhancing sequences inside the TCR-delta gene locus, using transient transfections with constructs containing DNA fragments cloned upstream to a reporter gene fused to a heterologous promoter. A 14-kb DNA region extending from the J delta 3 segment to 6 kb 3' to C delta was analyzed. We show the presence of positive regulatory sequences inside the J delta 3-C delta intron and have localized these sequences to two DNA fragments of approximately 300 and 258 bp. Analysis of cell specificity of the activation of such sequences demonstrates a T cell pattern for one of the two fragments. The nucleotide sequence of the T cell-specific element shows motifs sharing homology with previously described core enhancers.

Rearrangements of the T cell receptor delta gene in T acute lymphoblastic leukemia cells are distinct from those occurring in B lineage acute lymphoblastic leukemia and preferentially involve one V delta gene segment.

Rearrangement of the TCR-delta gene was studied using J delta, C delta, and V delta probes in 61 cases of acute lymphoblastic leukemia (ALL) and several cases of chronic lymphoid neoplasms to define the specificity and the diversity of rearrangements occurring at the delta locus. TCR-delta rearrangements or deletions were found in all T (33 cases) and B lineage (28 cases) ALL but not in any case of B cell chronic proliferations (13 cases). The restriction patterns of rearrangement were clearly distinct between T and B ALL and use of one V delta probe showed that rearrangement of the V delta IDP2 gene segment which is also productively rearranged in the Peer cell line, occurred frequently in T-ALL but never in B lineage ALL. Studies of WT31 and delta TCS1 antibody reactivity showed that at least 4 of 13 CD3+ T-ALL cases expressed the delta protein. CD4 and/or CD8 Ag expression were observed in some of the gamma delta expressing T-ALL. These data show that particular TCR-delta gene rearrangements occur in neoplastic early B cells and that the combinatorial diversity of TCR-delta rearrangements in T cells is higher than initially expected. In addition this study shows that an important proportion of CD3 positive T-ALL cases express the gamma delta heterodimer.