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B Ballester

Publications and source records attributed to B Ballester.

17 recordsLinked to original sources
PubMed2006

Ensembl 2007.

The Ensembl (http://www.ensembl.org/) project provides a comprehensive and integrated source of annotation of chordate genome sequences. Over the past year the number of genomes available from Ensembl has increased from 15 to 33, with the addition of sites for the mammalian genomes of elephant, rabbit, armadillo, tenrec, platypus, pig, cat, bush baby, common shrew, microbat and european hedgehog; the fish genomes of stickleback and medaka and the second example of the genomes of the sea squirt (Ciona savignyi) and the mosquito (Aedes aegypti). Some of the major features added during the year include the first complete gene sets for genomes with low-sequence coverage, the introduction of new strain variation data and the introduction of new orthology/paralog annotations based on gene trees.

Animals↗
PubMed2006

Gene expression profiling identifies molecular subgroups among nodal peripheral T-cell lymphomas.

The classification of peripheral T-cell lymphomas (PTCL) is still a matter of debate. To establish a molecular classification of PTCL, we analysed 59 primary nodal T-cell lymphomas using cDNA microarrays, including 56 PTCL and three T-lymphoblastic lymphoma (T-LBL). The expression profiles could discriminate angioimmunoblastic lymphoma, anaplastic large-cell lymphoma and T-LBL. In contrast, cases belonging to the broad category of 'PTCL, unspecified' (PTCL-U) did not share a single molecular profile. Using a multiclass predictor, we could separate PTCL-U into three molecular subgroups called U1, U2 and U3. The U1 gene expression signature included genes known to be associated with poor outcome in other tumors, such as CCND2. The U2 subgroup was associated with overexpression of genes involved in T-cell activation and apoptosis, including NFKB1 and BCL-2. The U3 subgroup was mainly defined by overexpression of genes involved in the IFN/JAK/STAT pathway. It comprised a majority of histiocyte-rich PTCL samples. Gene Ontology annotations revealed different functional profile for each subgroup. These results suggest the existence of distinct subtypes of PTCL-U with specific molecular profiles, and thus provide a basis to improve their classification and to develop new therapeutic targets.

Gene Expression Profiling↗
PubMed2003

Flow cytometry analysis of gamma-radiation-induced Epstein-Barr virus reactivation in lymphocytes.

Epstein-Barr virus (EBV), a member of the gamma-herpesvirus family, is involved in the development of several diseases, and the infection is believed to persist for life in latent form. Ionizing radiation at clinically relevant doses may increase the amount of virus reactivation in B cells, and the combination of radiation with stress could amplify EBV reactivation. In vitro experiments were performed on several cell lines, including EBV-positive Burkitt lymphoma cells. The presence of the immediate-early protein ZEBRA, which is a hallmark of EBV reactivation, was evaluated using flow cytometry, which enabled us to measure the percentage of ZEBRA-positive cells. The process was studied previously in the EBV-positive Burkitt lymphoma cell line B95-8. Forty-eight hours after irradiation alone, 13.6 and 19.9% ZEBRA-positive cells were observed at 2 and 4 Gy, respectively, compared to the basal level of 1.85%. Thus irradiation induces EBV reactivation. The addition of a glucocorticoid (the final effector of the stress response) had no effect on EBV reactivation in our model. However, the combination of radiation and treatment with a glucocorticoid (dexamethasone) increased the expression of ZEBRA in B95-8 cells (15.8 and 28.75% of the cells was positive at 24 and 48 h after gamma irradiation, respectively). Thus the combination of gamma radiation and a glucocorticoid may play an important role in EBV reactivation.

Cell Cycle↗
PubMed2001

The bacterial nucleoside N(6)-methyldeoxyadenosine induces the differentiation of mammalian tumor cells.

Contrary to bacterial DNA, mammalian DNA contains very little if any N(6)-methyldeoxyadenosine (MDA). The possible biological effect of this nucleoside on eukaryotic cells has been studied on different tumor cell lines. Addition of MDA to C6.9 glioma cells triggers a differentiation process and the expression of the oligodendroglial marker 2',3'-cyclic nucleotide 3'phosphorylase (CNP). The biological effects of N(6)-methyldeoxyadenosine were not restricted to C6.9 glioma cells since differentiation was also observed on pheochromocytoma and teratocarcinoma cell lines and on dysembryoplastic neuroepithelial tumor cells. The precise mechanism by which MDA induces cell differentiation remains unclear, but is related to cell cycle modifications. These data point out the potential interest of N(6)-methyldeoxyadenosine as a novel antitumoral and differentiation agent. They also raise the intriguing question of the loss of adenine methylation in mammalian DNA. Furthermore, the finding that a methylated nucleoside found in bacterial DNA induces a biological process might have implications in gene therapy approaches when plasmid DNAs are injected into humans.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗
PubMed1999

[Apoptosis and gamma rays].

Gamma radiation can induce cell death in lymphocytes. Apoptosis is characterized by numerous morphological, biochemical and molecular modifications measurable using various methods. Some radioprotectors have antioxidant properties and are able to inhibit radiation-induced DNA fragmentation and caspase activation. There are several caspases that cleave proteolytically many proteins and trigger phosphatidylserine externalization recognized by phagocytes. Three main proteins are involved in the regulation of radiation-induced apoptosis: p53, Fas and Bcl-2. The pharmacological regulation of cell death is discussed in order to investigate the subsequent effects related to cell regeneration following radiation injury.

Animals↗
PubMed1996

Radiation-induced apoptosis in thymocytes: inhibition by diethyldithiocarbamate and zinc.

Apoptosis is a process of physiological cell death characterized by DNA fragmentation, chromatin condensation, loss of membrane asymmetry, mitochondrial alterations and cell lethality. In the present study, apoptosis induced in thymocytes by gamma irradiation is evaluated by flow cytometry, by a diphenylamine colorimetric method and by gel electrophoresis. Treatment of thymocytes with diethyldithiocarbamate or zinc shows that these compounds can inhibit radiation-induced apoptosis. Moreover, a synergistic effect is observed by using combinations of both compounds: ZnSO4 potentiates the effect of diethyldithiocarbamate at concentrations at which the compounds used separately show a low efficacy. A study of kinetics shows that addition of 1 microM diethyldithiocarbamate + 50 microM ZnSO4 (the most efficient combination) after irradiation can decrease DNA fragmentation even when it is added 2-3 h after irradiation. However, 1 microM diethyldithiocarbamate + 50 microM ZnSO4 cannot prevent the radiation-induced loss of membrane asymmetry and the decrease in alteration of the mitochondrial membrane as measured by binding of merocyanine 540 and uptake of rhodamine 123, respectively.

Acetylcysteine↗
PubMed1995

DNA fragmentation induced in lymphocytes by gamma irradiation or dexamethasone: inhibition by diethyldithiocarbamate (DTC), potentiated by zinc.

Apoptosis is a process of physiological cell death characterized by DNA fragmentation, chromatin condensation, loss of membrane asymmetry and cell lethality. In the present study, apoptosis induced in thymocytes by dexamethasone or gamma irradiation is evaluated by flow cytometry, gel electrophoresis and other techniques. Treatment of thymocytes with DTC or zinc shows that these products can inhibit radiation- or dexamethasone-induced apoptosis. Moreover, a synergistic effect is observed by using associations of both products (5 microM DTC + 50 microM ZnSO4): ZnSO4 potentiates the effect of DTC at concentrations for which the molecules used separately show a low efficacy. These results indicate that DNA fragmentation induced by dexamethasone or irradiation in thymocytes share some identical mechanisms.

Animals↗
PubMedDate not supplied

[Study of the sentinel node in breast cancer using lymphoscintigraphy and a fast method for cytokeratin].

INTRODUCTION: Histopathological examination of the axillary sentinel node (SN) is becoming a routine procedure in the surgical phase of infiltrating ductal carcinoma of the breast (IDC). The SN exam may yield false negative cases mainly due to identification failure of the SN but some of the false negative cases may be the result of the pathological examination procedure applied. MATERIAL AND METHODS: Sixty two (62) cases of clinically staged N0 IDC of the breast by TNM nomenclature were assigned to breast surgery along with conventional axillary node dissection. The identification technique included lymphoscintigraphy and intraoperative gamma-detecting probe after peritumoral injection of 99mTc-labeled colloids.The histological study of SN was performed with paired 4 microm slices and staining with hematoxylin-eosin and with a fast method of cytokeratins for freezing. RESULTS: In only two of the 62 patients, it was not possible to identify the SN. Eighteen of the remaining 60 had SN involvement by metastasis, having no metastases in the other nodes of the axillary dissection in 6 of them. Ten of those were micrometastasis (size of metastasis= or <0.2 cm). In two out of these last 10 cases, diagnosis of the micrometastasis was only possible using slices stained with CK. There were no false negative results. CONCLUSIONS: The lymphoscintigraphy, after peritumoral injection of small volumes and low dose of the tracer, makes it possible to obtain excellent results in the intraoperative detection of the SN in breast cancer. The study of this SN with a fast method for CK decreases the number of false negative results of the technique.

Breast Neoplasms↗
PubMedDate not supplied

Effects of selenium supplementation on malignant lymphoproliferative pathologies associated with OF1 mouse ageing.

Low plasma selenium (Se) levels have been shown to correlate with increased cancer incidence in humans and in mice. This study was undertaken to investigate the ability of Se to decrease mortality rate and tumor production in ageing mice. Se (2.5 ppm) given as sodium selenite in drinking water to 8 months old OF1 mice, for 4 consecutive months, reduced significantly the mortality of mice with 6% and 50% mortality rate for Se and control groups, respectively. In addition 80% of control deaths resulted from a lymphoid cell neoplasma, while no one of Se supplemented mice produced tumor. Evaluation of parameters of free radical metabolism showed highly significant reduction of the antioxidant defence system in the liver of cancer mice, with a 78% decrease in GSH-Px activity, a 65% decrease in superoxide dismutase (SOD) activity, a 75% decrease in the GSH/GSSG ratio and a 62% decrease of plasma Se level, as compared to healthy old mice. Nevertheless in the conditions of our experiment, Se didn't really improve the endogenous antioxidant status of ageing mice.

Aging↗