Percorrer por autor "Barroso, Helena"
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- An ancestral HIV-2/simian immunodeficiency virus peptide with potent HIV-1 and HIV-2 fusion inhibitor activityPublication . Borrego, Pedro; Calado, Rita; Marcelino, José M.; Pereira, Patrícia; Quintas, Alexandre; Barroso, Helena; Taveira, Nuno"Objectives: To produce new fusion inhibitor peptides for HIV-1 and HIV-2 based on ancestral envelope sequences. Methods: HIV-2/simian immunodeficiency virus (SIV) ancestral transmembrane protein sequences were reconstructed and ancestral peptides were derived from the helical region 2 (HR2). The activity of one ancestral peptide (named P3) was examined against a panel of HIV-1 and HIV-2 primary isolates in TZM-bl cells and peripheral blood mononuclear cells and compared to T-20. Peptide secondary structure was analyzed by circular dichroism. Resistant viruses were selected and resistance mutations were identified by sequencing the env gene. Results: P3 has 34 residues and overlaps the N-terminal pocket-binding region and heptad repeat core of HR2. In contrast to T-20, P3 forms a typical a-helical structure in solution, binds strongly to the transmembrane protein, and potently inhibits both HIV-2 (mean IC50, 63.8 nmol/l) and HIV-1 (11 nmol/l) infection, including T-20-resistant isolates. The N43K mutation in the HR1 region of HIV-1 leads to 120-fold resistance to P3 indicating that the HR1 region in transmembrane glycoprotein is the target of P3. No HIV-2-resistant mutations could be selected by P3 suggesting that the genetic barrier to resistance is higher in HIV-2 than in HIV-1. HIV-1-infected patients presented significantly lower P3-specific antibody reactivity compared to T-20. Conclusion: P3 is an HIV-2/SIV ancestral peptide with low antigenicity, high stability, and potent activity against both HIV-1, including variants resistant to T-20, and HIV-2. Similar evolutionary biology strategies should be explored to enhance the production of antiviral peptide drugs, microbicides, and vaccines."
- Antibacterial effect of ozone on cariogenic bacteria and its potential prejudicial effect on dentin bond strength : an in vitro studyPublication . Santos, Marta; Leandro, Flávia; Barroso, Helena; Delgado, António H. S.; Proença, Luís; Polido, Mário; Cruz, Joana Vasconcelos eOzone is increasingly utilized in dental caries treatment due to its antibacterial properties. In a context of limited studies and no consensus on protocols, this research aims to assess ozone’s antibacterial efficacy on cariogenic bacteria and its potential adverse impact on dentin bond strength. Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, and Actinomyces naeslundii suspensions were exposed to 40 μg/mL of ozone gas and 60 μg/mL of ozonated water (80 s) via a medical ozone generator. Negative and positive control groups (chlorhexidine 2%) were included, and UFC/mL counts were recorded. To examine microtensile bond strength (µTBS), 20 human molars were divided into four groups, and class I cavities were created. After ozone application, samples were restored using an etch-and-rinse and resin composite, then sectioned for testing. The SPSS v. 28 program was used with a significance level of 5%. The µTBS results were evaluated using one-way ANOVA, Tukey HSD, and Games-Howell. Bacterial counts reduced from 106 to 101, but dentin µTBS was significantly impacted by ozone (ANOVA, p < 0.001). Despite ozone’s attractive antibacterial activity, this study emphasizes its detrimental effect on dentin adhesion, cautioning against its use before restorative treatments.
- Association of Herpesvirus and Periodontitis : a clinical and laboratorial case–control studyPublication . Picolo, Marta; Nobre, Miguel A de Araújo; Salvado, Francisco; Barroso, HelenaObjectives: A significant influence of the Herpesviridae family in the progression of periodontal disease has been suggested. The aim of this study was to investigate the potential association of four Herpesviruses (HSV-1, HSV-2, cytomegalovirus [CMV], and Epstein-Barr virus [EBV]) with periodontal disease using a qualitative test for evaluating the presence or absence of viral DNA in crevicular fluid samples of both healthy periodontal patients and periodontal compromised patients. Materials and methods: A case-control study was conducted in 100 participants at a university clinic. A qualitative test was used for evaluating the presence/absence of viral DNA in crevicular fluid samples of both healthy periodontal patients and periodontal compromised patients, and considering the periodontitis staging (stage II, stage III, and stage IV) and grading (grade A, grade B, and grade C). Statistical analysis: The distribution of the same exposure variables to the periodontitis staging and grading was compared using Chi-square, Fisher's exact, and Gamma tests depending on the variable characteristics. The significance level was set at 5%. The association of the variables: age, sex, diabetes, smoking, alcohol, and oral hygiene was also considered. Results: The prevalence of Herpesviridae family virus DNA was 6% for the periodontal healthy group and 60% for the periodontitis group (roughly 60% on periodontitis stages II, III, and IV, p <0.001; and twofold increase in moderate and rapid progression grades compared with the slow progression grade, p <0.001). HSV1 DNA was prevalent in all periodontitis stages and grades. HSV 2, EBV, and CMV DNA had increasing prevalence rates in more severe stages (stages III and IV, p <0.001); while considering periodontitis grade, HSV2 (p = 0.001), CMV (p = 0.019) and EBV (p <0.001) DNA were prevalent only in grades B and C, with EBV DNA registering a marked prevalence in grade C. Conclusion: A significant different distribution of Herpesviridae virus DNA per each stage of disease was registered.
- Baseline susceptibility of primary HIV-2 to entry inhibitorsPublication . Borrego, Pedro; Calado, Rita; Marcelino, José M; Bártolo, Inês; Rocha, Cheila; Cavaco-Silva, Patrícia; Doroana, Manuela; Antunes, Francisco; Maltez, Fernando; Caixas, Umbelina; Barroso, Helena; Taveira, NunoBackground: The baseline susceptibility of primary HIV-2 to maraviroc (MVC) and other entry inhibitors is currently unknown.
- Beach sand and the potential for infectious disease transmission: observations and recommendationsPublication . Solo-Gabriele, Helena M.; Harwood, Valerie J.; Kay, David; Fujioka, Roger S.; Sadowsky, Michael J.; Whitman, Richard L.; Wither, Andrew; Caniça, Manuela; Fonseca, Rita Carvalho da; Duarte, Aida; Edge, Thomas A.; Gargaté, Maria J.; Gunde-Cimerman, Nina; Hagen, Ferry; McLellan, Sandra L.; Silva, Alexandra Nogueira da; Babič, Monika Novak; Prada, Susana; Rodrigues, Raquel; Romão, Daniela; Sabino, Raquel; Samson, Robert A.; Segal, Esther; Staley, Christopher; Taylor, Huw D.; Veríssimo, Cristina; Viegas, Carla; Barroso, Helena; Brandão, João C."Recent studies suggest that sand can serve as a vehicle for exposure of humans to pathogens at beach sites, resulting in increased health risks. Sampling for microorganisms in sand should therefore be considered for inclusion in regulatory programmes aimed at protecting recreational beach users from infectious disease. Here, we review the literature on pathogen levels in beach sand, and their potential for affecting human health. In an effort to provide specific recommendations for sand sampling programmes, we outline published guidelines for beach monitoring programmes, which are currently focused exclusively on measuring microbial levels in water. We also provide background on spatial distribution and temporal characteristics of microbes in sand, as these factors influence sampling programmes. First steps toward establishing a sand sampling programme include identifying appropriate beach sites and use of initial sanitary assessments to refine site selection. A tiered approach is recommended for monitoring. This approach would include the analysis of samples from many sites for faecal indicator organisms and other conventional analytes, while testing for specific pathogens and unconventional indicators is reserved for high-risk sites. Given the diversity of microbes found in sand, studies are urgently needed to identify the most significant aetiological agent of disease and to relate microbial measurements in sand to human health risk."
- Can chlorhexidine gluconate baths reduce fungal colonisation in intensive care unit patients?Publication . Nascimento, Teresa; Inácio, João; Guerreiro, Daniela; Patrício, Patrícia; Proença, Luís; Toscano, Cristina; Diaz, Priscila; Barroso, HelenaBackground: Chlorhexidine Gluconate (CHG) bathing is widely used in Intensive Care Units (ICUs) to reduce bacterial colonisation, yet its efficacy against fungal skin colonisation, particularly Candida spp., is not well understood. This study aimed to evaluate the impact of daily CHG bathing on Candida colonisation among ICU patients. Methods: From 2020 to 2022, axillary/inguinal swabs were collected from 675 ICU patients across three units on admission (Day 1, D1), Day 5 (D5) and Day 8 (D8). Patients received daily CHG bathing (either 2% impregnated wipes or 4% liquid solution) from D1 to D5, followed by soap-and-water bathing from Day 6 to D8. Standard and molecular microbiological methods were used to identify fungal species, and colony-forming units (CFUs) were quantified. Colonisation rates and fungal burden were compared across time points and bathing protocols. Results: A total of 988 swabs from 675 patients were collected, 675 on D1, 203 on D5 and 110 on D8. CHG bathing had no significant impact on Candida burden at individual time points, (D1, p = 0.223; D5, p = 0.939 and D8, p = 0.669). No significant differences in colonisation or fungal burden were observed between the use of 4% CHG solution and 2% CHG-impregnated wipes upon ICU admission. However, in the subgroup of 89 patients monitored longitudinally, a transient reduction in colonisation was observed during the CHG bathing period (D1–D5), followed by a significant increase during the soap-and-water period (D6–D8) (p = 0.005; between periods: p < 0.001). Among the 329 positive swabs, 274 yielded > 100 CFU/ml. High colony counts of C. albicans (> 1000 CFU/mL) were observed, with no significant association between colonisation levels and specific Candida species (p = 0.940). Conclusions: CHG bathing demonstrated only a limited and transient impact on Candida colonisation in ICU patients. Colonisation rates rebounded after cessation of CHG use, suggesting ongoing acquisition during ICU stay. These findings highlight the need for additional or alternative infection control measures targeting fungal pathogens in critical care settings.
- Candida spp. colonization among intensive care unit patients : preliminary resultsPublication . Nascimento, Teresa; Inácio, João; Ferreira, Isabel; Diaz, Priscila; Freitas, Paulo; Barroso, HelenaCandida spp. colonization is recognized as a major risk factor for invasive candidiasis. To assess patient colonization, upon admission and during their stay in intensive care units (ICU), a surveillance study has been conducted since January 2020, in the Lisbon area of Portugal. A total of 219 swab samples were obtained from 113 ICU patients. The yeast identification was conducted by microbiological conventional and molecular methods. Upon admission to the ICU, 27% of patients were already colonized, and 17% became colonized during their ICU stay. Candida albicans was the most isolated species. These results may offer an opportunity for prevention of candidemia.
- Children and sand play: screening of potential harmful microorganisms in sandboxes, parks, and beachesPublication . Romão, Daniela; Sabino, Raquel; Veríssimo, Cristina; Viegas, Carla; Barroso, Helena; Duarte, Aida; Solo-Gabriele, Helena; Gunde-Cimerman, Nina; Babič, Monika Novak; Marom, Tal; Brandão, JoãoSand serves as a reservoir for potentially pathogenic microorganisms. Children, a high-risk group, can acquire infections from sand in sandboxes, recreational areas, and beaches. This paper reviews the microbes in sands, with an emphasis on fungi. Recreational areas and beach sands have been found to harbor many types of fungi and microbes. A newly emerging group of fungi of concern include the black yeast-like fungi. After establishing that sand is a reservoir for fungi, clinical manifestations of fungal infections are described with an emphasis on ocular and ear infections. Overall, we recommend environmental studies to develop monitoring strategies for sand and studies to evaluate the link between fungi exposure in sand and human health impacts.
- Effect of a tea tree oil mouthwash on plaque-induced gingivitis when comparing to chlorhexidine: an exploratory randomised clinical trialPublication . Menat, Alfred; Rozan, Cecília; Barroso, Helena; Proença, Luís; Salema-Oom, Madalena; Botelho, João; Zhiri, Abdesselam; Manso, Ana CristinaGingivitis, the most common periodontal disease, is an inflammatory condition of the gingiva resulting from bacterial biofilm accumulation without periodontal attachment loss. Chlorhexidine (CHX) is the gold standard for chemical plaque control, yet its prolonged use is associated with undesirable side effects. Tea tree essential oil (TTO, Melaleuca alternifolia), with documented antimicrobial and anti-inflammatory properties, has emerged as a potential natural alternative. This exploratory randomized, controlled, triple-blind clinical trial evaluated the antimicrobial, cytotoxic, and clinical effects of a 1% TTO-based mouthwash compared with 0.12% CHX in 30 adults with plaque-induced gingivitis. Both mouthwashes significantly reduced plaque and gingival indices as well as bacterial counts after 15 days (p < 0.001), with no significant intergroup differences in clinical outcomes. CHX achieved a greater reduction in bacterial load, while TTO presented fewer adverse effects, limited to mild taste alteration and transient increase in salivary flow. Both formulations exhibited in vitro cytotoxicity, though clinical tolerance was high. These results suggest that, under the tested conditions, TTO formulation at 1% (v/v) exerts an antibacterial effect comparable to CHX, while displaying a dose-dependent pattern.
- Effects of probiotic short-term regiment on oral health parameters in children : a pilot randomized controlled trialPublication . Starck, Edouard; Machado, Vanessa; Botelho, João; Proença, Luís; Barroso, Helena; Ascenso, Carla; Rozan, CecíliaBackground/Objectives: Streptococcus mutans (S. mutans) is a primary cariogenic bacterium contributing to biofilm acidogenicity and enamel demineralization. Conventional caries prevention relies mainly on mechanical plaque control and dietary modification, but probiotics have emerged as potential adjuncts for oral microbiota modulation. This pilot randomized controlled trial aimed to evaluate the short-term effects of a multi-strain probiotic containing Lactobacillus and Bifidobacterium on clinical and microbiological parameters associated with dental caries in children. Methods: A double-blind, randomized, placebo-controlled clinical trial was conducted in 40 children aged 6–14 years from a community setting. Participants were randomly allocated (1:1) to receive either probiotic or placebo lozenges for 30 days. Clinical assessments included the Gingival Index (GI), Plaque Index (PI), International Caries Detection and Assessment System (ICDAS), salivary pH, buffering capacity, and salivary S. mutans concentration. The study was preregistered (10.17605/OSF.IO/GKVUW) and ethically approved. Results: The intervention was well tolerated, with no adverse events reported and high participant acceptability. Despite there being no statistically significant differences in any clinical or microbiological parameter (p > 0.05), we found trends toward higher salivary pH, improved buffering capacity, and reduced S. mutans counts in the probiotic group. Conclusions: Short-term probiotic supplementation was safe and well accepted among children but did not produce statistically significant improvements in oral health parameters over 30 days. These findings highlight the feasibility of probiotic use in pediatric populations and support the need for larger, longer-term trials to clarify their potential role as adjuncts in caries prevention.