Search

This study sought to assess newborn feeding knowledge and attitudes among medical students. A sample of 649 Portuguese medical students completed an online survey containing a sociodemographic questionnaire, the Newborn Feeding Ability Questionnaire (NFA), and the Iowa Infant Feeding Attitudes Scale (IIFAS). The overall sample showed moderate scores for all variables. Gender analysis identified significant differences only for the dimension related to the benefits of skin-to-skin contact between mother and newborn where women scored higher. Analysis by year of training found that students with more years of training scored higher on all variables of newborn feeding knowledge that were positively correlated and were positive predictors of newborn feeding attitudes. Students with fewer years of training scored higher on work practices interfering with newborn feeding ability, which were negatively correlated and were negative predictors of newborn feeding attitudes. These results demonstrate that medical students with more years of training are the most prepared, however, the moderate results of the sample raise concerns. Our results point to the importance of providing medical students with adequate knowledge in order to influence their attitudes toward newborn feeding and contribute to better working practices for future health professionals.

Introduction: The evidence for beta-blocker use in patients after acute coronary syndrome (ACS), particularly in those with left ventricular (LV) dysfunction, dates from the late 1990s. We aimed to assess the role of beta-blockers in a contemporary population of patients with ACS. Methods: Propensity-score matching (1:2) was performed for the use of beta-blockers in a population of consecutive patients admitted to our department with ACS. After matching, 1520 patients were analyzed. Cox regression analysis was used to assess the impact of beta-blocker use on the primary outcome (one-year all-cause mortality). Results: Patients who did not receive beta-blockers were less aggressively treated with other pharmacological and invasive interventions and had higher one-year mortality (20.3% vs. 7.5%). Beta-blocker use was an independent predictor of mortality, with a significant relative risk reduction of 56%. The other independent predictors were age, diabetes, LV dysfunction, heart rate, systolic blood pressure and creatinine on admission. The impact of beta-blockers was significant for all classes of LV function, including patients with normal or mildly reduced ejection fraction. Conclusions: In a contemporary ACS population, we confirmed the benefits of beta-blocker use after ACS, including in patients with normal or mildly to moderately impaired LV function. Resumo: Introdução: A evidência para a utilização dos bloqueadores-beta em doentes após síndrome coronária aguda (SCA), particularmente em doentes com disfunção ventricular esquerda (VE) é do final dos anos 90. Foi nosso objetivo analisar o papel dos bloqueadores-beta numa população contemporânea de doentes com SCA. Métodos: Foi realizado emparelhamento de score de propensão (1:2) para a utilização de bloqueadores-beta numa população consecutiva de doentes admitidos no nosso serviço por SCA. Após emparelhamento, foram analisados 1520 doentes. Foi utilizada a análise de regressão de Cox para avaliar o impacto da utilização dos bloqueadores-beta na mortalidade de todas as causas a um ano de seguimento. Resultados: Os doentes que não receberam bloqueadores-beta foram tratados de forma menos agressiva com outras intervenções farmacológicas e invasivas e tiveram maior mortalidade a um ano (20,3% versus 7,5%). A utilização de bloqueadores-beta foi preditor independente de mortalidade com redução significativa do risco relativo de 56%. Os restantes preditores independentes foram a idade, diabetes, disfunção VE, frequência cardíaca, pressão arterial sistólica e creatinina na admissão. O impacto dos bloqueadores-beta foi significativo em todas as classes de função VE, incluindo doentes com fração de ejeção normal ou ligeiramente reduzida. Conclusões: Numa população contemporânea de doentes com SCA, confirmámos os benefícios da terapêutica bloqueadora-beta após SCA, incluindo em doentes com função VE normal ou com compromisso ligeiro a moderado. Keywords: Beta-blockers, Myocardial infarction, Prognosis, Palavras-chave: Bloqueadores-beta, Enfarte miocárdio, Prognóstico

Urinary neutrophil gelatinase-associated lipocalin (uNGAL) has been suggested as potential early marker of delayed graft function (DGF) following kidney transplantation (KTx). We conducted a prospective study in 40 consecutive KTx recipients to evaluate serial changes of uNGAL within the first week after KTx and assess its performance in predicting DGF (dialysis requirement during initial posttransplant week) and graft function throughout first year. Urine samples were collected on post-KTx days 0, 1, 2, 4, and 7. Linear mixed and multivariable regression models, receiver-operating characteristic (ROC), and areas under ROC curves were used. At all-time points, mean uNGAL levels were significantly higher in patients developing DGF (n=18). Shortly after KTx (3–6 h), uNGAL values were higher in DGF recipients (on average +242 ng/mL, considering mean dialysis time of 4.1 years) and rose further in following days, contrasting with prompt function recipients. Day-1 uNGAL levels accurately predicted DGF (AUC-ROC = 0.93), with a performance higher than serum creatinine (AUC-ROC = 0.76), and similar to cystatin C (AUC-ROC = 0.95). Multivariable analyses revealed that uNGAL levels at days 4 and 7 were strongly associated with one-year serum creatinine. Urinary NGAL is an early marker of graft injury and is independently associated with dialysis requirement within one week after KTx and one-year graft function.

The assessment of early bilingual proficiency often involves analysis of the child’s productive lexicon at different stages in acquisition. This approach implies two assumptions: that bilingual awareness is measured by lexical production, and that the child has attained a level in development compatible with the production of equivalent lexical items in each language, before any so-called language ‘differentiation’ becomes apparent. This paper discusses these assumptions, in the light of the linguistic production of three Portuguese-Swedish bilingual siblings between the ages of 0;7 and 1;9, and argues that the children’s ability to produce distinctive prosodic and phonetic patterns associated with each language at this early stage in linguistic development provides clear evidence of bilingual awareness before and at the very outset of the one-word stage.

Short tandem DNA repeats and telomerase compose the telomere structure in the vast majority of eukaryotic organisms. However, such a conserved organisation has not been found in dipterans. While telomeric DNA in Drosophila is composed of specific retrotransposons, complex terminal tandem repeats are present in chromosomes of Anopheles and chironomid species. In the sciarid Rhynchosciara americana, short repeats (16 and 22 bp long) tandemly arrayed seem to reach chromosome ends. Moreover, in situ hybridisation data using homopolymeric RNA probes suggested in this species the existence of a third putative chromosome end repeat enriched with (dA).(dT) homopolymers. In this work, chromosome micro-dissection and PCR primed by homopolymeric primers were employed to clone these repeats. Named T-14 and 93 % AT-rich, the repetitive unit is 14 bp long and appears organised in tandem arrays. It is localised in five non-centromeric ends and in four interstitial bands of R. americana chromosomes. To date, T-14 is the shortest repeat that has been characterised in chromosome ends of dipterans. As observed for short tandem repeats identified previously in chromosome ends of R. americana, the T-14 probe hybridised to bridges connecting non-homologous polytene chromosome ends, indicative of close association of T-14 repeats with the very end of the chromosomes. The results of this work suggest that R. americana represents an additional example of organism provided with more than one DNA sequence that is able to reach chromosome termini.

Nucleoli, nuclear organelles in which ribosomal RNA is synthesized and processed, emerge from nucleolar organizers (NORs) located in distinct chromosomal regions. In polytene nuclei of dipterans, nucleoli of some species can be observed under light microscopy exhibiting distinctive morphology: Drosophila and chironomid species display well-formed nucleoli in contrast to the fragmented and dispersed nucleoli seen in sciarid flies. The available data show no apparent relationship between nucleolar morphology and location of NORs in Diptera. The regulation of rRNA transcription involves controlling both the transcription rate per gene as well as the proportion of rRNA genes adopting a proper chromatin structure for transcription, since active and inactive rRNA gene copies coexist in NORs. Transcription units organized in nucleosomes and those lacking canonical nucleosomes can be analyzed by the method termed psoralen gel retarding assay (PGRA), allowing inferences on the ratio of active to inactive rRNA gene copies. In this work, possible connections between chromosomal location of NORs and proportion of active rRNA genes were studied in Drosophila melanogaster, and in chironomid and sciarid species. The data suggested a link between location of NORs and proportion of active rRNA genes since the copy number showing nucleosomal organization predominates when NORs are located in the pericentric heterochromatin. The results presented in this work are in agreement with previous data on the chromatin structure of rRNA genes from distantly related eukaryotes, as assessed by the PGRA.

The characterisation of sequences at chromosome ends of Rhynchosciara americana was continued with the screening of a genomic library using as a probe a short repeat identified in a previous report (M-22, 22 bp) which was found to be specific for noncentromeric termini of this species. Simple repeats, complex tandem and apparently dispersed repeats were present in the genomic clones analysed. Repetitive sequences do not define individual chromosome tips as they were found in all noncentromeric ends. A novel and unusually short tandem repeat type for dipteran chromosome ends (named M-16) composed of 16 nucleotides and frequently associated with M-22 arrays was characterised in this work. Islands of M-16 and M-22 tandem repeats were found in all the genomic clones analysed. Individual probes representative of each repetitive element hybridised not only to all noncentromeric ends of R. americana chromosomes but also to inter-telomeric bridges. This contrasted with the other repeat types which displayed sub-telomeric localisation as seen by double detection of hybridised probe and telomeric reverse transcriptase. Some stretches composed of M-16 and M-22 tandem repeats localised in different regions of the analysed genomic clones were either identical or showed sequence similarity that was unexpectedly higher than the mean sequence similarity observed among repeats within each of their tandem arrays. The occurrence of segmental duplications, as deduced by sequence analyses involving the two repeats that appeared to reach chromosome ends, might indicate the involvement of this type of duplication process in the chromosome end maintenance in this species.

In Drosophila, telomere retrotransposons counterbalance the loss of telomeric DNA. The exceptional mechanism of telomere recovery characterized in Drosophila has not been found in lower dipterans (Nematocera). However, a retroelement resembling a telomere transposon and termed "RaTART" has been described in the nematoceran Rhynchosciara americana. In this work, DNA and protein sequence analyses, DNA cloning, and chromosomal localization of probes obtained either by PCR or by screening a genomic library were carried out in order to examine additional features of this retroelement. The analyses performed raise the possibility that RaTART represents a genomic clone composed of distinct repetitive elements, one of which is likely to be responsible for its apparent enrichment at chromosome ends. RaTART sequence in addition allowed to assess a novel subtelomeric region of R. americana chromosomes that was analyzed in this work after subcloning a DNA fragment from a phage insert. It contains a complex repeat that is located in the vicinity of simple and complex tandem repeats characterized previously. Quantification data suggest that the copy number of the repeat is significantly lower than that observed for the ribosomal DNA in the salivary gland of R. americana. A short insertion of the RaTART was identified in the cloned segment, which hybridized preferentially to subtelomeres. Like RaTART, it displays truncated sequences related to distinct retrotransposons, one of which has a conceptual translation product with significant identity with an endonuclease from a lepidopteran retrotransposon. The composite structure of this DNA stretch probably reflects mobile element activity in the subtelomeric region analyzed in this work.

Ribosomal RNA genes of most insects are interrupted by R1/R2 retrotransposons. The occurrence of R2 retrotransposons in sciarid genomes was studied by PCR and Southern blot hybridization in three Rhynchosciara species and in Trichosia pubescens. Amplification products with the expected size for non-truncated R2 elements were only obtained in Rhynchosciara americana. The rDNA in this species is located in the proximal end of the X mitotic chromosome but in the salivary gland is associated with all four polytene chromosomes. Approximately 50% of the salivary gland rDNA of most R. americana larval groups analysed had an insertion in the R2 site, while no evidence for the presence of R1 elements was found. In-situ hybridization results showed that rDNA repeat units containing R2 take part in the structure of the extrachromosomal rDNA. Also, rDNA resistance to Bal 31 digestion could be interpreted as evidence for nonlinear rDNA as part of the rDNA in the salivary gland. Insertions in the rDNA of three other sciarid species were not detected by Southern blot and in-situ hybridization, suggesting that rDNA retrotransposons are significantly under-represented in their genomes in comparison with R. americana. R2 elements apparently restricted to R. americana correlate with an increased amount of repetitive DNA in its genome in contrast to other Rhynchosciara species. The results obtained in this work together with previous results suggest that evolutionary changes in the genus Rhynchosciara occurred by differential genomic occupation not only of satellite DNA but possibly also of rDNA retrotransposons.

The characterisation of chromosome end (terminal and sub-terminal) sequences of Rhynchosciara americana chromosomes was continued with the screening of a plasmid library made of amplified DNA fragments from a microdissected chromosome tip. An insert chosen for analysis hybridised to two chromosome ends and contains two microsatellite arrays in close vicinity to a sequence (named M-47), part of which is significantly similar to minisatellites of Salmonidae that are frequently present in the vicinity of microsatellite arrays. PCR results using a single primer representative of M-47 elements suggest that they are also repetitive in Rhynchosciara genomes. In addition, total single primer PCR products hybridised to the non-telocentric end subset of R. americana chromosomes. Another plasmid microlibrary made of chromosome tips amplified by a single M-47 primer was screened for repeats of Rhynchosciara chromosomes. Selected inserts that hybridised strongly to non-telocentric ends of R. americana and R. hollaenderi have a tandem array of 22 bp repeats (M-22). There is sequence divergence among M-22 repeats but their mean similarity is significantly high in relation to the M-22 consensus sequence derived from the cloned tandem array. M-22 elements lie distal to the 414 bp sub-telomeric satellite array characterised previously as suggested by double labelling for M-22 hybridisation and reverse transcriptase. M-47 elements, formerly identified in Salmonidae, thus contribute to specify unusually short repeats composing the sub-telomeric structure of two Rhynchosciara species.

The chromosomal localization of ribosomal DNA (rDNA) was studied in polytene and diploid tissues of four sciarid species, Trichosia pubescens, Rhynchosciara americana, R. milleri and Schwenkfeldina sp. While hybridization to mitotic chromosomes showed the existence of a single rDNA locus, ribosomal probes hybridized to more than one polytene chromosome region in all the species analyzed as a result of micronucleolar attachment to specific chromosome sites. Micronucleoli are small, round bodies containing transcriptionally active, probably extrachromosomal rDNA. In T. pubescens the rDNA is predominantly localized in chromosome sections X-10 and X-8. In R. americana the rDNA is frequently found associated with centromeric heterochromatin of the chromosomes X, C, B and A, and also with sections X-1 and B-13. Ribosomal probes in R. milleri hybridized with high frequency to pericentric and telomeric regions of its polytene complement. Schwfenkfeldina sp. displays a remarkably unusual distribution of rDNA in polytene nuclei, characterized by the attachment of micronucleoli to many chromosome regions. The results showed that micronucleoli preferentially associate with intercalary or terminal heterochromatin of all sciarid flies analyzed and, depending on the species, are attached to a few (Trichosia), moderate (Rhynchosciara) or a large (Schwenkfeldina sp.) number of polytene chromosome sites.

The chromosomal response to temperature shock in Rhynchosciara americana is similar to that observed in other Diptera. After a 33 degrees C/90 min or a 36 degrees C/30 min shock the reaction for RNA polymerase II (RpII) is enhanced at five loci. The most prominent of these was identified by in situ hybridization as the site of the hsp70 gene. At 33 degrees C, an accumulation of heat shock factor (HSF) and an increase in the level of RpII was observed at some heat shock loci after 5 min and reached a maximum after 15 min at most loci. The pattern of accumulation of HSF and RpII at individual heat shock loci was similar and their increases were generally coordinated among the loci. RpII gradually decreased at sites active prior to shock, the rate of decrease varying with the site. The B2 DNA puff retained RpII for a significant length of time while the histone locus still contained RpII after a shock of 90 min. With a 36 degrees C/30 min shock, the size of the heat shock puffs and the intensities of HSF and RpII peaked at 1-4 h post stress. The level of HSF declined rapidly after 1 h while the level of RpII remained high for an additional 4 h. The reaction of the DNA puffs to heat shock varied. Usually they did not regress completely and retained traces of RpII. BrdU incorporation continued at both amplifying and non-amplifying bands after shock but on average it appeared depressed for about 24 h post stress.

The characterization of chromosome end sequences of Rhynchosciara americana was initiated with the screening of a plasmid microlibrary made from a microdissected polytene chromosome tip. A 268 bp insert chosen for analysis hybridized specifically to non-telocentric chromosome ends in which reverse transcriptase had been previously identified. Southern-blot hybridization of R. americana genomic DNA cut with XbaI, the only restriction site identified in the 268 bp probe, showed a ladder composed of multimers of a band in the range of 400 bp indicating a tandem array of the repeat partially represented in the cloned fragment. The complete repeat unit obtained by inverse PCR is 414 bp long, 67% AT-rich, characterized by the restriction sites XbaI and SalI and displays features typical of a nematoceran telomeric satellite. The telomere-like repeat is apparently absent from the chromosomes of two other Rhynchosciara species, R. baschanti and R. milleri. Double staining for satellite hybridization and reverse transcriptase in R. americana suggests that the arrays composed of the telomeric-like satellite do not reach the chromosome ends. This may indicate that telomeric-like features of some nematoceran terminal satellites do not warrant their telomeric position.