Participació i equivalència del rendiment dels alumnes en les activitats de docència no presencial tutoritzada (ADNPT) i en els exàmens parcials

Es presenten els resultats de participació i de rendiment assolits pels estudiants de l'assignatura optativa "Biologia del desenvolupament i Teratogènia" de la Diplomatura de Logopèdia. Es comparen les dades relatives a quatre activitats de docència no presencial tutoritzada (ADNPT) i de les parts equivalents dels dos exàmens parcials. La presentació de materials, tutories i entrega de treballs de les ADNPT s'ha fet via Campus Virtual. Els exàmens, no test, constaven de diversos tipus de pregunta. Del total de 32 alumnes matriculats el 37,5% no van participar a cap ADNPT i el 31,25 no es van presentar a cap examen. El 41%, 13 alumnes, van participar a totes les ADTNP i es van presentar als dos exàmens. Aquest últim contingent d'alumnes, considerat com el grup més implicat, ha estat seleccionat per analitzar el grau d'equivalència entre els resultats assolits a les ADNPT i als exàmens. La diferència entre ambdues notes no superava el 5% en el 46,2% d'alumnes; en el 30,8% estava entre el 5 i el 10% i en el 23,1% d'aquesta mostra d'alumnes superava el 10 %. En el 69,2% dels alumnes la nota de les ADNPT superava la dels exàmens (totes les qualificacions estaven en l'escala de 0 a 10). El grau de participació cal considerar-lo mig i les equivalències en el rendiment va ser millor en les ADNPT (mitjana: 7,0) que en els exàmens (mitjana: 6,2). Aquestes dades suggereixen més facilitat per assolir millor rendiment en les ADNPT que en els exàmens, no obstant la repercussió final a la nota no varia excessivament quan es ponderen els resultats: la nota mitjana, si les notes de les ATPN signifiquessin el 10%, seria de 6,3 mentre que si es valoressin el 50% arribarien fins al 6,6. Results concerning the involvement and achievement of the students of "Biologia del desenvolupament i Teratogènia", an elective matter of the Logopedics Diplomature, are presented. The results of four activities of "non-presential teaching" (NPT) and its equivalent parts in the mid-term exams are compared. The delivery of the teaching materials, the tutorials and the hand in of personal works had been carried out by means of Virtual Campus. The exams, of non-multiple choice format, were composed by different sort of questions. The 37,5 percent of 32 enrolled students did not participate in any NPT activity and 31,25 percent did not take any exam. Thirteen students, 41 %, of the enrolled students, did all the NPT activities and took both exams. This group of students, considered the most involved in the matter, was the chosen to analyze the degree of equivalency between the results of the NPT and the exams. The difference between both marks were less than 5% in the 46,2%; between 5 and 10 % in the 30,8% and higher than 10% in 23% of the students The qualifications reached in NPT were higher than exam's in 69,2% of the cases (all the marks were expressed in the 0-10 scale). The degree of involvement must be considered in the average and the achievement was better in the NPT (median: 7,0) than in exams (median: 6,2). This results suggest that is easier to reach better achievement in NPT than in exams, however the repercussion in the final mark did not change excessively when results are weighted: the median mark would be 6,3 if NPT would represent the 10% of the final mark and 6,6 if them represent the 50%

Cytogenetic effects of irradiation on somatic and germ cells

This paper summarizes the results obtained in two of the research projects carried out in our laboratory within the radiation protection programs of the Consejo de Seguridad Nuclear and the European Union. These two research lines are fundamentally interconnected, since the analysis of the cytogenetic effects of radiation on somatic cells studies the consequences of occupational or accidental exposure to radiation for the individual, especially from the point of view of developing some type of malignancy, while the studies carried out in germ cells evaluate the risk of exposure for future generations, through the transmission of chromosome abnormalities via affected spermatozoa. In both cases these studies, which were mainly carried out during the last six years, in addition to providing basic data for the assessment of the consequences of radiation exposure and defining the steps to be taken to prevent the transmission of chromosome anomalies to the offspring in cases of therapeutic exposure, have also been fundamental in developing more effective techniques for the evaluation of the cytogenetic consequences of exposure to radiation

Aneuploïdia radioinduïda

Descripció del recurs: el 19-08-2008Consultable des del TDXTítol obtingut de la portada digitalitzadaLa radiació ionitzant és un agent mutagènic, amb un conegut efecte clastogènic, que a nivell de DNA es pot traduir en la formació de reorganitzacions cromosòmiques estructurals. A part del DNA, la radiació podria afectar altres elements cel·lulars implicats en la segregació cromosòmica originant aneuploïdia, que és la condició on el nombre de cromosomes d'una cèl·lula o organisme difereix d'un múltiple exacte del nombre haploide. Podem distingir dos tipus d'aneuploïdia, la constitucional, quan totes les cèl·lules de l'organisme es veuen afectades i la podem trobar en avortaments espontanis i en defectes del naixement; i l'aneuploïdida no constitucional, quan afecta unes quantes cèl·lules de l'organisme, i la màxima importància la trobem en les cèl·lules tumorals. Es va valorar la inducció i persistència d'aneuploïdia pels raigs gamma en cèl·lules somàtiques i la sensibilitat de diferents estadis de la gametogènesi en cèl·lules germinals. L'anàlisi de la inducció d'anomalies cromosòmiques numèriques en limfòcits humans irradiats in vitro a 1, 2 i 4 Gy es va fer combinant les tècniques del bloqueig de la citocinesi i la hibridació in situ fluorescent (FISH) amb sondes de DNA específiques pel centròmer de tres cromosomes. D'aquesta manera les cèl·lules resultants de la primera divisió en cultiu queden englobades en un mateix citoplasma i es pot avaluar la distribució dels senyals entre els nuclis i/o els micronuclis. Es va observar un increment estadísticament significatiu de la freqüència de micronuclis totals, dependent de la dosi que s'ajustava a una corba lineal quadràtica; fet que indica que majoritàriament contindran fragments acèntrics resultants de l'efecte clastogèncic de la radiació. Pel què fa els mecanismes que originen aneuploïdia, com són la no disjunció i la pèrdua anafàsica, es va observar un increment significatiu a 1, 2 i 4 Gy per la no disjunció i a 2 i 4 Gy per la pèrdua anafàsica, sent superiors els valors de no disjunció. Per estudiar la inducció i la persistència de l'aneuploïdia es van irradiar ratolins in vivo a 1 i 2 Gy de raigs gamma i es van establir cultius de limfòcits de la melsa a 0, 1, 3 i 28 dies després d'haver irradiat als animals. L'anàlisi dels limfòcits binucleats amb sondes de DNA específiques de dos cromosomes no va mostrar increments significatius en la freqüència de no disjunció en cap dia ni dosi estudiada. Mentre que per la pèrdua anafàsica es van observar increments significatius en els cultius establers fins a tres dies després d'haver irradiat els animals, amb la característica que majoritàriament els micronuclis presentaven dos senyals pel mateix cromosoma deixant als nuclis principals monosòmics. A l'analitzar metafases de limfòcits de ratolins irradiats in vivo a 2 Gy es va observar que el 50% de les segregacions anòmales trobades en els nuclis interfàsics serien degudes a cromosomes sencers, mentre que el 50% restant s'originarien a partir d'anomalies cromosòmiques estructurals inestables, com poden ser els cromosomes dicèntrics i els fragments acèntrics. Finalment, el comportament observat en cèl·lules somàtiques no té perquè ser extrapolable a les cèl·lules germinals, i per això es va fer un estudi analitzant espermatozoides de ratolí que havien estat irradiats als estadis d'espermatogoni cèl·lula mare, espermatòcit I, espermàtide i espermatozoide en una localització testicular i epididimal. Aplicant la FISH amb sondes de DNA subcentromèriques per dos cromosomes es va valorar el grau de disomia i de diploïdia. Es van trobar increments significatius dels dos tipus d'anomalies cromosòmiques en els espermatozoides que havien estat irradiats en els estadis d'espermatogoni cèl·lula mare, espermatòcit I, espermàtide, resultant de segregacions anòmales en els dos primers estadis, i de trencaments dins de la regió marcada en l'últim.Ionizing radiation is a mutagenic agent with a well-known clastogenic effect. At DNA level, effects of ionizing radiation can be detected as chromosome reorganizations. Apart from DNA, other cellular elements like those implicated in chromosome segregation, could be affected and originate aneuploidy, which is the condition where the cell or organism chromosome number differs from a multiple exact of the haploid number. We can distinguish two types of aneuploidy: constitutional aneuploidy and non-constitutional aneuploidy. In the first case, all cells of the organism are affected and it is present in miscarriages and birth defects. In the second case, few cells of the organism are affected and it has major importance in tumour cells. In this work, aneuploidy induction and persistence by gamma rays in somatic cells and the sensitivity of different stages of gametogenesis have been analyzed. The analysis of numerical chromosome abnormalities induced in human lymphocytes irradiated in vitro at 1, 2 and 4 Gy was made combining the techniques of cytokinesis-block micronucleus assay and fluorescent in situ hybridization (FISH) using three centromeric specific DNA probes. In this way, the binucleated cells resulting from the first division during the cell culture become included in the same cytoplasm and the distribution of the signals between the nuclei and/or the micronuclei can be evaluated. A dose-dependent significant increase in the micronuclei frequency was observed, which fits to a linear-quadratic curve; this fact indicates that most of them contain acentric fragments resulting from the clastogenic effect of radiation. Related to the mechanisms that originate aneuploidy, a significant increase was observed at 1, 2 and 4 Gy for nondisjunction and at 2 and 4 Gy for the chromosome loss, being higher for nondisjunction. The analysis of aneuploidy induction and persistence was made on splenocytes cell cultures established at 0, 1, 3 and 28 days post-irradiation (dpi) from mice irradiated in vivo at 1 and 2 Gy of gamma rays. The analysis of the binucleated lymphocytes with two subcentromeric specific DNA probes did not show significant increases in nondisjunction frequency at any day or dose studied. For chromosome loss significant increases in the cell cultures established at 0, 1 and 3 dpi were observed, with the characteristic that most micronuclei showed two signals for the same chromosome leaving the main nuclei monosomic. The metaphase analysis of mice lymphocytes irradiated in vivo at 2 Gy showed that 50% of the segregation abnormalities scored in the interphase nuclei analysis would correspond to whole chromosomes, while the remaining 50% would originate from unstable structural chromosomal abnormalities, as dicentric chromosomes and acentric fragments. Finally, we hypothesize that the behavior observed in somatic cells could be different from the behavior in germ cells. For this reason, an analysis of mouse sperm that had been irradiated in the stages of stem cell spermatogonium, spermatocyte I, spermatid and sperm in a testicular and epididimal location was made. Applying FISH with two subcentromeric DNA probes the degree of disomy and of diploidy was assessed. Significant increases of the two types of chromosome abnormalities in sperm irradiated at stem cell spermatogonium, spermatocyte I and spermatid stages were found, due to chromosome malsegregation in the first two stages and to breakage in the labeled region in the last stage

Cytogenetic effects of irradiation on somatic and germ cells

This paper summarizes the results obtained in two of the research projects carried out in our laboratory within the radiation protection programs of the Consejo de Seguridad Nuclear and the European Union. These two research lines are fundamentally interconnected, since the analysis of the cytogenetic effects of radiation on somatic cells studies the consequences of occupational or accidental exposure to radiation for the individual, especially from the point of view of developing some type of malignancy, while the studies carried out in germ cells evaluate the risk of exposure for future generations, through the transmission of chromosome abnormalities via affected spermatozoa. In both cases these studies, which were mainly carried out during the last six years, in addition to providing basic data for the assessment of the consequences of radiation exposure and defining the steps to be taken to prevent the transmission of chromosome anomalies to the offspring in cases of therapeutic exposure, have also been fundamental in developing more effective techniques for the evaluation of the cytogenetic consequences of exposure to radiation

Nucleotide, cytogenetic and expression impact of the human chromosome 8p23.1 inversion polymorphism

Background: the human chromosome 8p23.1 region contains a 3.8-4.5 Mb segment which can be found in different orientations (defined as genomic inversion) among individuals. The identification of single nucleotide polymorphisms (SNPs) tightly linked to the genomic orientation of a given region should be useful to indirectly evaluate the genotypes of large genomic orientations in the individuals. Results: we have identified 16 SNPs, which are in linkage disequilibrium (LD) with the 8p23.1 inversion as detected by fluorescent in situ hybridization (FISH). The variability of the 8p23.1 orientation in 150 HapMap samples was predicted using this set of SNPs and was verified by FISH in a subset of samples. Four genes (NEIL2, MSRA, CTSB and BLK) were found differentially expressed (p<0.0005) according to the orientation of the 8p23.1 region. Finally, we have found variable levels of mosaicism for the orientation of the 8p23.1 as determined by FISH. Conclusion: by means of dense SNP genotyping of the region, haplotype-based computational analyses and FISH experiments we could infer and verify the orientation status of alleles in the 8p23.1 region by detecting two short haplotype stretches at both ends of the inverted region, which are likely the relic of the chromosome in which the original inversion occurred. Moreover, an impact of 8p23.1 inversion on gene expression levels cannot be ruled out, since four genes from this region have statistically significant different expression levels depending on the inversion status. FISH results in lymphoblastoid cell lines suggest the presence of mosaicism regarding the 8p23.1 inversion

Centrosome clustering and Cyclin D1 gene amplification in double minutes are common events in chromosomal unstable bladder tumors

Background: Aneuploidy, centrosome abnormalities and gene amplification are hallmarks of chromosome instability (CIN) in cancer. Yet there are no studies of the in vivo behavior of these phenomena within the same bladder tumor. Methods: Twenty-one paraffin-embedded bladder tumors were analyzed by conventional comparative genome hybridization and fluorescence in situ hybridization (FISH) with a cyclin D1 gene (CCND1)/centromere 11 dual-color probe. Immunofluorescent staining of α, β and γ tubulin was also performed. Results: Based on the CIN index, defined as the percentage of cells not displaying the modal number for chromosome 11, tumors were classified as CIN-negative and CIN-positive. Fourteen out of 21 tumors were considered CIN-positive. All T1G3 tumors were included in the CIN-positive group whereas the majority of Ta samples were classified as CIN-negative tumors. Centrosome clustering was observed in six out of 12 CIN-positive tumors analyzed. CCND1 amplification in homogeneously staining regions was present in six out of 14 CIN-positive tumors; three of them also showed amplification of this gene in double minutes. Conclusions: Complex in vivo behavior of CCND1 amplicon in bladder tumor cells has been demonstrated by accurate FISH analysis on paraffin-embedded tumors. Positive correlation between high heterogeneity, centrosome abnormalities and CCND1 amplification was found in T1G3 bladder carcinomas. This is the first study to provide insights into the coexistence of CCND1 amplification in homogeneously staining regions and double minutes in primary bladder tumors. It is noteworthy that those patients whose tumors showed double minutes had a significantly shorter overall survival rate (p < 0.001)

Quantitative analysis of somatically acquired and constitutive uniparental disomy in gastrointestinal cancers

Altres ajuts: GCB13131592CAST de la Fundación Científica de la Asociación Española Contra el Cáncer; PERIS (SLT002/16/00398, Generalitat de Catalunya)Somatically acquired uniparental disomies (aUPDs) are frequent events in solid tumors and have been associated with cancer-related genes. Studies assessing their functional consequences across several cancer types are therefore necessary. Here, we aimed at integrating aUPD profiles with the mutational status of cancer-related genes in a tumor-type specific manner. Using TCGA datasets for 1,032 gastrointestinal cancers, including colon (COAD), rectum (READ), stomach (STAD), esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC), we show a non-random distribution of aUPD, suggesting the existence of a cancer-specific landscape of aUPD events. Our analysis indicates that aUPD acts as a "second hit" in Knudson's model in order to achieve biallelic inactivation of tumor suppressor genes. In particular, APC , ARID1A and NOTCH1 were recurrently inactivated by the presence of homozygous mutation as a consequence of aUPD in COAD and READ, STAD and ESCC, respectively. Furthermore, while TP53 showed inactivation caused by aUPD at chromosome arm 17p across all tumor types, copy number losses at this genomic position were also frequent. By experimental and computationally inferring genome ploidy, we demonstrate that an increased number of aUPD events, both affecting the whole chromosome or segments of it, were present in highly aneuploid genomes compared to near-diploid tumors. Finally, the presence of mosaic UPD was detected at a higher frequency in DNA extracted from peripheral blood lymphocytes of patients with colorectal cancer compared to healthy individuals. In summary, our study defines specific profiles of aUPD in gastrointestinal cancers and provides unequivocal evidence of their relevance in cance