Optical/NIR stellar absorption and emission-line indices from luminous infrared galaxies

We analyze a set of optical-to-near-infrared long-slit nuclear spectra of 16 infrared-luminous spiral galaxies. All of the studied sources present H$_2$ emission, which reflects the star-forming nature of our sample, and they clearly display H I emission lines in the optical. Their continua contain many strong stellar absorption lines, with the most common features due to Ca I, Ca II, Fe I, Na I, Mg I, in addition to prominent absorption bands of TiO, VO, ZrO, CN and CO. We report a homogeneous set of equivalent width (EW) measurements for 45 indices, from optical to NIR species for the 16 star-forming galaxies as well as for 19 early type galaxies where we collected the data from the literature. This selected set of emission and absorption-feature measurements can be used to test predictions of the forthcoming generations of stellar population models. We find correlations among the different absorption features and propose here correlations between optical and NIR indices, as well as among different NIR indices, and compare them with model predictions. While for the optical absorption features the models consistently agree with the observations,the NIR indices are much harder to interpret. For early-type spirals the measurements agree roughly with the models, while for star-forming objects they fail to predict the strengths of these indices.Comment: accepted for publication in MNRA

Antimicrobial properties of membrane-active dodecapeptides derived from MSI-78

Antimicrobial peptides (AMPs) are a class of broad-spectrum antibiotics known by their ability to disrupt bacterial membranes and their low tendency to induce bacterial resistance, arising as excellent candidates to fight bacterial infections. In this study we aimed at designing short 12-mer AMPs, derived from a highly effective and broad spectrum synthetic AMP, MSI-78 (22 residues), by truncating this peptide at the N- and/or C-termini while spanning its entire sequence with 1 amino add (aa) shifts. These designed peptides were evaluated regarding antimicrobial activity against selected gram-positive Staphylococcus strains and the gram-negative Pseudomonas aeruginosa (P. aeruginosa). The short 12-mer peptide CEM1 (GIGMFLKKAKICF) was identified as an excellent candidate to fight P. aeruginosa infections as it displays antimicrobial activity against this strain and selectivity, with negligible toxicity to mammalian cells even at high concentrations. However, in general most of the short 12-mer peptides tested showed a reduction in antimicrobial activity, an effect that was more pronounced for gram-positive Staphylococcus strains. Interestingly, CEM1 and a highly similar peptide differing by only one aa-shift (CEM2: IGKFLKKAKICFG), showed a remarkably contrasting AMP activity. These two peptides were chosen for a more detailed study regarding their mechanism of action, using several biophysical assays and simple membrane models that mimic the mammalian and bacterial lipid composition. We confirmed the correlation between peptide helicity and antimicrobial activity and propose a mechanism of action based on the disruption of the bacterial membrane permeability barrier

Whole-genome analysis of Leptospira interrogans to identify potential vaccine candidates against leptospirosis

Leptospirosis is an important global human and veterinary health problem. Humans can be infected by exposure to chronically infected animals and their environment. An important focus of the current leptospiral research is the identification of outer membrane proteins (OMPs). Due to their location, leptospiral OMPs are likely to be relevant in host-pathogen interactions, hence their potential ability to stimulate heterologous immunity. The existing whole-genome sequence of Leptospira interrogans serovar Copenhageni offers a unique opportunity to search for cell surface proteins. Predicted genes encoding potential surface proteins were amplified from genomic DNA by PCR methodology and cloned into an Escherichia coli expression system. The partially purified recombinant proteins were probed by Western blotting with sera from human patients diagnosed with leptospirosis. Sixteen proteins, out of a hundred tested, were recognized by antibodies present in human sera. Four of these proteins were conserved among eight serovars of L. interrogans and absent in the non-pathogenic Leptospira biflexa. These proteins might be useful for the diagnosis of the disease as well as potential vaccine candidates.Facultad de Ciencias ExactasInstituto de Biotecnologia y Biologia Molecula

Association between age at first sexual intercourse and subsequent human papillomavirus infection: results of a Brazilian screening program

Objetivo: descrever a idade de início da atividade sexual (sexarca) e a sua associação com a idade das mulheres com a infecção por papilomavírus humano (HPV) e com as alterações citológicas no exame de papanicolaou. Métodos: mulheres da população geral foram recrutadas para participar de um estudo de rastreamento de câncer cervical e lesões pré-malignas. Após a aplicação de questionário comportamental, foram submetidas ao rastreamento com gia cervical e teste para DNA de HPV de alto risco, por meio de Captura Híbrida 2. Este projeto faz parte do Latin American Screening Study, que envolve mulheres do Brasil e da Argentina, e os dados aqui apresentados referem-se aos centros brasileiros nas cidades de Porto Alegre, São Paulo e Campinas. Resultados: de 8.649 mulheres entrevistadas, 8.641 relataram atividade sexual prévia e foram incluídas na análise. A média de idade no momento da entrevista foi de 38,1±11,04 anos, com início da atividade sexual em média aos 18,5±4,0 anos. Identificamos que a idade do início da atividade sexual aumenta de acordo com o aumento da faixa etária no momento da entrevista, isto é, mulheres mais novas relataram sexarca mais precoce que mulheres mais velhas (p<0,001). Em relação à infecção por HPV de alto risco, do total de mulheres que haviam iniciado as relações sexuais, 3.463 foram testadas, com 17,3% de positividade para HPV. Notadamente, em todos os centros, as mulheres com idade ao início da atividade sexual abaixo da média da população entrevistada apresentaram positividade maior para HPV (20,2%) do que as mulheres com sexarca em idade acima da média (12,5%) – Odds Ratio (OR)=1,8 (IC95%=1,5-2,2; p<0,001). Em relação à citologia, mulheres com sexarca abaixo da média de idade apresentaram também maior percentual de citologia alterada ≥ ASC-US (6,7%) do que mulheres com sexarca em idade maior que a média (4,3%) – OR=1,6 (IC95%=1,3-2,0; p<0,001). Conclusões: a infecção por HPV e a presença de alterações citológicas identificadas no rastreio de lesões cervicais em uma população assintomática estiveram significativamente associadas à idade mais precoce no início das relações sexuais. Ademais, identificamos também que as mulheres desta amostra apresentaram diminuição da idade ao início da atividade sexual, nas últimas décadas, sugerindo importante causa para o acréscimo da prevalência de HPV e as lesões decorrentes desta infecção.Purpose: to investigate women’s age at their first sexual intercourse and its correlation with their present age, human papillomavirus (HPV) infection and cytological abnormalities at Pap smear. Methods: women from the general population were invited to be screened for cervical cancer and pre-malignant lesions. After answering a behavior questionnaire, they were submitted to screening with cervical cytology and high-risk HPV testing with Hybrid Capture 2 (HC2). This report is part of the Latin American Screening (LAMS) study, that comprises centers from Brazil and Argentina, and the data presented herein refer to the Brazilian women evaluated at the cities of Porto Alegre, São Paulo and Campinas. Results: from 8,649 women that answered the questionnaire, 8,641 reported previous sexual activity and were included in this analysis. The mean age at the interview was 38.1±11.0 years and the mean age at the first sexual intercourse was 18.5±4.0 years. The age at the first sexual intercourse increased along with the age at the interview, i.e., younger women reported they had begun their sexual life earlier than older women (p<0.001). From the total of women who had already begun having sexual intercourse, 3,643 patients were tested for high-risk HPV infection and 17.3% of them had positive results. In all the centers, it became clear that the women with the first sexual intercourse at ages below the mean age of all the population interviewed presented higher rates of HPV infection (20.2%) than the women with the first sexual intercourse at ages above the mean (12.5%) – Odds Ratio (OR) 1.8 (IC95% 1.5-2.2;p<0,001). According to the cytology, the women with first sexual intercourse at ages under the mean, presented higher percentage of abnormal cytology ≥ ASC-US (6.7%) than the women with the first sexual intercourse at ages above the mean (4.3%) – OR 1.6 (IC95% 1.3-2.;p<0.001). ConclusionS: the high-risk HPV infection and cytological abnormalities identified during the asymptomatic population screening were significantly associated to the women’s age at the first sexual intercourse. Additionally, we have also identified that the women’s age at the first sexual intercourse has decreased during the last decades, suggesting an important contribution to the increase of HPV infection and the subsequent cervical lesions.Comissão Europeia - programa INCO-DEV (International Cooperation Development) Contrato #ICA4-2001-10013

Whole-genome analysis of Leptospira interrogans to identify potential vaccine candidates against leptospirosis

Leptospirosis is an important global human and veterinary health problem. Humans can be infected by exposure to chronically infected animals and their environment. An important focus of the current leptospiral research is the identification of outer membrane proteins (OMPs). Due to their location, leptospiral OMPs are likely to be relevant in host-pathogen interactions, hence their potential ability to stimulate heterologous immunity. The existing whole-genome sequence of Leptospira interrogans serovar Copenhageni offers a unique opportunity to search for cell surface proteins. Predicted genes encoding potential surface proteins were amplified from genomic DNA by PCR methodology and cloned into an Escherichia coli expression system. The partially purified recombinant proteins were probed by Western blotting with sera from human patients diagnosed with leptospirosis. Sixteen proteins, out of a hundred tested, were recognized by antibodies present in human sera. Four of these proteins were conserved among eight serovars of L. interrogans and absent in the non-pathogenic Leptospira biflexa. These proteins might be useful for the diagnosis of the disease as well as potential vaccine candidates.Facultad de Ciencias ExactasInstituto de Biotecnologia y Biologia Molecula

Evaluation of the effects of Quercetin and Kaempherol on the surface of MT-2 cells visualized by atomic force microscopy

AbstractThis study investigated the anti-viral effects of the polyphenolic compounds Quercetin and Kaempherol on the release of HTLV-1 from the surface of MT-2 cells. Atomic force microscopy (AFM) was used to scan the surface of the MT-2 cells. MT-2 cells were fixed with 100% methanol on round glass lamina or cleaved mica and dried under UV light and laminar flow. The images were captured on a Multimode equipment monitored by a NanoScope IIId controller from Veeco Instruments Inc operated in tapping mode and equipped with phase-imaging hardware. The images demonstrated viral budding structures 131±57nm in size, indicating profuse viral budding. Interestingly, cell-free viruses and budding structures visualized on the surface of cells were less common when MT-2 was incubated with Quercetin, and no particles were seen on the surface of cells incubated with Kaempherol. In summary, these data indicate that HTLV-1 is budding constantly from the MT-2 cell surface and that polyphenolic compounds were able to reduce this viral release. Biological samples were analyzed with crude cell preparations just after cultivation in the presence of Quercetin and Kaempherol, showing that the AFM technique is a rapid and powerful tool for analysis of antiviral activity of new biological compounds

Hormonal contraceptives and the length of their use are not independent risk factors for high-risk HPV infections or high-grade CIN

AIMS: To evaluate the role of hormonal contraceptives as a risk factor of high-risk human papillomavirus (HR-HPV), cervical intraepithelial lesions (CIN) and cervical cancer in our multi-center population-based LAMS (Latin American Screening) study. METHODS: A cohort study with >12,000 women from Brazil and Argentina using logistic regression to analyze the covariates of hormonal contraception (HOC - oral, injections, patches, implants, vaginal ring and progesterone intrauterine system) use followed by multivariate modeling for predictors of HR-HPV and CIN2+. RESULTS: HR-HPV infection was a consistent risk factor of high-grade CIN in all three groups of women. The length of HOC use was not significantly related to high-grade squamous intraepithelial lesions (HSIL)+ Pap (p = 0.069), LSIL+ Pap (p = 0.781) or ASCUS+ (p = 0.231). The same was true with the length of HOC use and histology CIN3+ (p = 0.115) and CIN2+ (p = 0.515). Frequently, HOC users have previously shown more HPV-related lesions, as well as lower HPV prevalence if they were current smokers. But HOC use and time of usage were not independent risk factors of either HR-HPV infection or high-grade CIN using multiple logistic regressions. CONCLUSIONS: No evidence was found for an association between the use of HOC with an increased risk for HR-HPV infection or high-grade CIN in this cohort.This study is a part of the ongoing LAMS (Latin American Screening) study, entitled: Improving Health Systems Towards Equality-Based Control of Cervical Cancer in Latin America, and is supported by the INCO-DEV Program of the European Commission (Project No. ICA4-CT-2001-10013). The generous contribution of Digene Corporation (USA) who donated the HCII tests at our disposal is gratefully acknowledged