229 research outputs found

    Deep-intronic ATM mutation detected by genomic resequencing and corrected in vitro by antisense morpholino oligonucleotide (AMO)

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    Recent development of next-generation DNA sequencing (NGS) techniques is changing the approach to search for mutations in human genetic diseases. We applied NGS to study an A-T patient in which one of the two expected mutations was not found after DHPLC, cDNA sequencing and MLPA screening. The 160-kb ATM genomic region was divided into 31 partially overlapping fragments of 4–6 kb and amplified by long-range PCR in the patient and mother, who carried the same mutation by segregation. We identified six intronic variants that were shared by the two genomes and not reported in the dbSNP(132) database. Among these, c.1236-405C>T located in IVS11 was predicted to be pathogenic because it affected splicing. This mutation creates a cryptic novel donor (5′) splice site (score 1.00) 405 bp upstream of the exon 12 acceptor (3′) splice site. cDNA analysis showed the inclusion of a 212-bp non-coding ‘pseudoexon' with a premature stop codon. We validated the functional effect of the splicing mutation using a minigene assay. Using antisense morpholino oligonucleotides, designed to mask the cryptic donor splice-site created by the c.1236-405C>T mutation, we abrogated the aberrant splicing product to a wild-type ATM transcript, and in vitro reverted the functional ATM kinase impairment of the patients' lymphoblasts. Resequencing is an effective strategy for identifying rare splicing mutations in patients for whom other mutation analyses have failed (DHPLC, MLPA, or cDNA sequencing). This is especially important because many of these patients will carry rare splicing variants that are amenable to antisense-based correction

    The role of fault rock fabric in the dynamics of laboratory faults

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    Fault stability is inherently linked to the frictional and healing properties of fault rocks and associated fabrics. Their complex interaction controls how the stored elastic energy is dissipated, that is, through creep or seismic motion. In this work, we focus on the relevance of fault fabrics in controlling the reactivation and slip behavior of dolomite-anhydrite analog faults. We designed a set of laboratory experiments where we first develop fault rocks characterized by different grain size reduction and localization at normal stresses of σN = 15, 35, 60, and 100 MPa and second, we reload and reactivate these fault rocks at the frictional stability transition, achieved at σN = 35 MPa by reducing the machine stiffness. If normal stress is lowered this way, reactivation occurs with relatively large stress drops and large peak-slip velocities. Subsequent unstable behavior produces slow stick-slip events with low stress drop and with either asymmetric or Gaussian slip velocity function depending on the inherited fault fabric. If normal stress is raised, deformation is accommodated within angular cataclasites promoting stable slip. The integration of microstructural data (showing brittle reworking of preexisting textures) with mechanical data (documenting restrengthening and dilation upon reactivation) suggests that frictional and chemically assisted healing, which is common in natural faults during the interseismic phase, can be a relevant process in developing large instabilities. We also conclude that fault rock heterogeneity (fault fabric) modulates the slip velocity function and thus the dynamics of repeating stick-slip cycles

    The Mobilome-Enriched Genome of the Competence-Deficient Streptococcus pneumoniae BM6001, the Original Host of Integrative Conjugative Element Tn5253, Is Phylogenetically Distinct from Historical Pneumococcal Genomes

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    Streptococcus pneumoniae is an important human pathogen causing both mild and severe diseases. In this work, we determined the complete genome sequence of the S. pneumoniae clinical isolate BM6001, which is the original host of the ICE Tn5253. The BM6001 genome is organized in one circular chromosome of 2,293,748 base pairs (bp) in length, with an average GC content of 39.54%; the genome harbors a type 19F capsule locus, two tandem copies of pspC, the comC1-comD1 alleles and the type I restriction modification system SpnIII. The BM6001 mobilome accounts for 15.54% (356,521 bp) of the whole genome and includes (i) the ICE Tn5253 composite; (ii) the novel IME Tn7089; (iii) the novel transposon Tn7090; (iv) 3 prophages and 2 satellite prophages; (v) 5 genomic islands (GIs); (vi) 72 insertion sequences (ISs); (vii) 69 RUPs; (viii) 153 BOX elements; and (ix) 31 SPRITEs. All MGEs, except for the GIs, produce excised circular forms and attB site restoration. Tn7089 is 9089 bp long and contains 11 ORFs, of which 6 were annotated and code for three functions: integration/excision, mobilization and adaptation. Tn7090 is 9053 bp in size, flanked by two copies of ISSpn7, and contains seven ORFs organized as a single transcriptional unit, with genes encoding for proteins likely involved in the uptake and binding of Mg2+ cations in the adhesion to host cells and intracellular survival. BM6001 GIs, except for GI-BM6001.4, are variants of the pneumococcal TIGR4 RD5 region of diversity, pathogenicity island PPI1, R6 Cluster 4 and PTS island. Overall, prophages and satellite prophages contain genes predicted to encode proteins involved in DNA replication and lysogeny, in addition to genes encoding phage structural proteins and lytic enzymes carried only by prophages. & phi;BM6001.3 has a mosaic structure that shares sequences with prophages IPP69 and MM1 and disrupts the competent comGC/cglC gene after chromosomal integration. Treatment with mitomycin C results in a 10-fold increase in the frequency of & phi;BM6001.3 excised forms and comGC/cglC coding sequence restoration but does not restore competence for genetic transformation. In addition, phylogenetic analysis showed that BM6001 clusters in a small lineage with five other historical strains, but it is distantly related to the lineage due to its unique mobilome, suggesting that BM6001 has progressively accumulated many MGEs while losing competence for genetic transformation

    Translational Radiobiological Boron Neutron Capture Therapy (BNCT) Studies for the Treatment of Different Pathologies: A Bench to Bedside Approach

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    Boron Neutron Capture Therapy (BNCT) is a binary cancer treatment modality that combines irradiation with a thermal or epithermal neutron beam with the administration of boron-10 carriers that are taken up preferentially by neoplastic cells. The high linear energy transfer alpha particles and recoiling 7 Li nuclei emitted during the boron-10 neutron-capture reaction 10B(n,α)7 Li, have a range of 5-9 µm in tissue and are known to have a high Relative Biological Effectiveness (RBE). In this way, BNCT would potentially target tumor tissue selectively, largely sparing normal tissue. Clinical trials of BNCT for the treatment of glioblastoma multiforme and/ or melanoma and, more recently, head and neck tumors, liver metastases, lung metastases and mesothelioma have been performed or are under way in Argentina, Europe, Japan, Taiwan, and the US. To date, the clinical results have shown a potential therapeutic advantage for this technique but undoubtedly leave room for improvement. Translational radiobiological studies in appropriate in vivo experimental models are pivotal to progress in this field. A significant part of our translational research efforts have been focused on exploring new applications of BNCT and optimizing BNCT for different pathologies, employing a bench to bedside approach that bridges the gap between research and clinical application. Although our work includes the assessment of the therapeutic potential of novel boron compounds in our experimental models, a large proportion of our studies have been devoted to optimize the delivery of boron compounds currently authorized for their use in humans such as Boron phenylalanine (BPA) and decahydrodecaborate (GB-10). In addition, we have designed and tested different BNCT treatment strategies tailored for different pathologies, for varying degrees of disease progression and for different clinical conditions of the patient. Some examples involve: 1) The combined use of BPA and GB-10 to improve tumor boron targeting homogeneity in the hamster cheek pouch oral cancer model, in a colon carcinoma liver metastases model in BDIX rats and in a diffuse lung metastases model in BDIX rats; 2) Aberrant tumor blood vessel normalization to improve boron delivery in the oral cancer model; 3) Sequential BNCT (BPA-BNCT followed by GB-10- BNCT with a 24-48 h interval) in the oral cancer model to optimize therapeutic efficacy and minimize mucositis in the dose-limiting precancerous tissue in the case of patients requiring abbreviated treatment; 4) Electroporation to improve the micro distribution of boron delivered by GB-10 in the oral cancer model; 5) Double applications of BNCT with 4-6 weeks interval to optimize therapeutic efficacy, reduce toxicity in terms of mucositis and inhibit the development of second primary tumors from precancerous tissue in the oral cancer model for the case of patients that do not require abbreviated treatment; 5) Assessment of the therapeutic efficacy and potential toxicity of BNCT in the liver metastases and diffuse lung metastases models in BDIX rats; 6) Local administration of GB10 or BPA for effective low dose Boron Neutron Capture Synovectomy (BNCS) for the treatment of Rheumatoid Arthritis in a model of antigen-induced arthritis in rabbits; 7) BNCT-induced local and abscopal effect in an ectopic model of colon carcinoma in BDIX rats. The knowledge gained from these radiobiological studies would contribute to design safe and effective clinical BNCT protocols. In particular, the BNCT protocols used to perform our ongoing and to date successful clinical-veterinary BNCT studies at RA-6 for cats and dogs with spontaneous head and neck cancer with no therapeutic option, are partially based on the lessons learnt from these translational studies.Fil: Schwint, Amanda Elena. Comisión Nacional de Energía Atómica. Gerencia de Area de Aplicaciones de la Tecnología Nuclear. Gerencia de Radiobiología (Centro Atómico Constituyentes); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Monti Hughes, Andrea. Comisión Nacional de Energía Atómica. Gerencia de Area de Aplicaciones de la Tecnología Nuclear. Gerencia de Radiobiología (Centro Atómico Constituyentes); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garabalino, Marcela Alejandra. Comisión Nacional de Energía Atómica. Gerencia de Area de Aplicaciones de la Tecnología Nuclear. Gerencia de Radiobiología (Centro Atómico Constituyentes); ArgentinaFil: Pozzi, Emiliano César Cayetano. Comisión Nacional de Energía Atómica. Gerencia de Area de Aplicaciones de la Tecnología Nuclear. Gerencia de Radiobiología (Centro Atómico Constituyentes); ArgentinaFil: Heber, Elisa Mercedes. Comisión Nacional de Energía Atómica. Gerencia de Area de Aplicaciones de la Tecnología Nuclear. Gerencia de Radiobiología (Centro Atómico Constituyentes); ArgentinaFil: Trivillin, Verónica Andrea. Comisión Nacional de Energía Atómica. Gerencia de Area de Aplicaciones de la Tecnología Nuclear. Gerencia de Radiobiología (Centro Atómico Constituyentes); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Impact of asymptomatic genital tract infections on in vitro Fertilization (IVF) outcome

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    BACKGROUND: Infertility is estimated to affect approximately 9-30% of reproductive-aged couples. Several conditions involving one or both partners may contribute to infertility. The aim of this study is to evaluate the role of asymptomatic genital tract infections in the outcome of In Vitro Fertilization (IVF) in couples with infertility. METHODS: A total of 285 infertile couples were enrolled in the study. Vaginal/endocervical swabs and semen samples were collected and subjected to microbiological analysis. Spermiograms were carried out on semen specimens, and lactobacilli were quantified in vaginal swabs. Data were associated with IVF results and analysed by using non parametric tests and multivariate analysis. RESULTS: Microbiological analysis showed that 46.3% of couples presented with an asymptomatic genital tract infection. Spermiogram results showed a significantly diminished motility of sperm cells in samples positive to microbiological testing compared to negative specimens. Enterococcus faecalis was the most prevalent species (11.6%) in positive semen samples and was found to negatively affect both sperm morphology (p = 0.026) and motility (p = 0.003). Analysis of genital swabs from females showed that the presence of E. faecalis (p<0.0001), Escherichia coli (p = 0.0123), Streptococcus agalactiae (p<0.0001), and Gardnerella vaginalis (p = 0.0003) was significantly associated to reduced levels of vaginal lactobacilli. Association of microbiological data with IVF outcome showed that 85.7% of IVF+ couples was microbiologically negative, while IVF was successful in just 7.5% of couples infected with E. faecalis and/or U. urealyticum and/or M. hominis (p = 0.02). CONCLUSIONS: The results show the negative impact of E. faecalis on sperm quality and the association of definite bacterial pathogens with reduced levels of vaginal lactobacilli. The presence of E. faecalis and/or U. urealyticum and/or M. hominis in genital samples of infertile couples is predictive for a negative outcome of IVF

    Teachings of our translational studies on boron neutron capture therapy (BNCT): thinking “outside the box”

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    BNCT is a technique for the treatment of solid tumors. BNCT is considered a binary technique because it involves two components that exert little or no action individually but induce a significant effect when they combine. BNCT is based on the combination of neutron irradiation and the administration of 10B compounds that are incorporated selectively by tumor tissue via different mechanisms, depending on the boron carrier.Fil: Schwint, Amanda Elena. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garabalino, Marcela Alejandra. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Monti Hughes, Andrea. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pozzi, Emiliano César Cayetano. Comisión Nacional de Energía Atómica; ArgentinaFil: Heber, Elisa Mercedes. Comisión Nacional de Energía Atómica; ArgentinaFil: Palmieri, Mónica Alejandra. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Trivillin, Verónica Andrea. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
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