Browsing by Issue Date, starting with "2020-12-15"
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- Collaborative study: Quantification of total folate in food using an efficient single-enzyme extraction combined with LC-MS/MSPublication . Ložnjak Švarc, Petra; Oveland, E.; Strandler, H.S.; Kariluoto, S.; Campos-Giménez, E.; Ivarsen, E.; Malaviole, I.; Motta, Carla; Rychlik, M.; Striegel, L.; Jakobsen, J.Quantification of the specific folate vitamers to estimate total folate in foods is not standardized. A collaborative study, including eight European laboratories, was conducted in order to determine the repeatability and reproducibility of the method for folate quantification in foods using the plant-origin γ-glutamyl hydrolase as part of the extraction procedure. The seven food samples analyzed represent the food groups; fruits, vegetables, dairy products, legumes, offal, fish, and fortified infant formula. The homogenization step was included, and six folate vitamers were analyzed using LC-MS/MS. Total folate content, expressed as folic acid equivalent, was 17–490 μg/100 g in all samples. Horwitz ratio values were within the acceptable range (0.60–1.94), except for fish. The results for fortified infant formula, a certified reference material (NIST 1869), confirmed the trueness of the method. The collaborative study is part of a standardization project within the Nordic Committee on Food Analysis (NMKL).
- Towards a systematic use of effect biomarkers in population and occupational biomonitoringPublication . Zare Jeddi, Maryam; Hopf, Nancy B.; Viegas, Susana; Price, Anna Bal; Paini, Alicia; van Thriel, Christoph; Benfenati, Emilio; Ndaw, Sophie; Bessems, Jos; Behnisch, Peter A.; Leng, Gabriele; Duca, Radu-Corneliu; Verhagen, Hans; Cubadda, Francesco; Brennan, Lorraine; Ali, Imran; David, Arthur; Mustieles, Vicente; Fernandez, Mariana F.; Louro, Henriqueta; Pasanen-Kase, RobertEffect biomarkers can be used to elucidate relationships between exposure to environmental chemicals and their mixtures with associated health outcomes, but they are often underused, as underlying biological mechanisms are not understood. We aim to provide an overview of available effect biomarkers for monitoring chemical exposures in the general and occupational populations, and highlight their potential in monitoring humans exposed to chemical mixtures. We also discuss the role of the adverse outcome pathway (AOP) framework and physiologically based kinetic and dynamic (PBK/D) modelling to strengthen the understanding of the biological mechanism of effect biomarkers, and in particular for use in regulatory risk assessments. An interdisciplinary network of experts from the European chapter of the International Society for Exposure Science (ISES Europe) and the Organization for Economic Co-operation and Development (OECD) Occupational Biomonitoring activity of Working Parties of Hazard and Exposure Assessment group worked together to map the conventional framework of biomarkers and provided recommendations for their systematic use. We summarized the key aspects of this work here, and discussed these in three parts. Part I, we inventory available effect biomarkers and promising new biomarkers for the general population based on the H2020 Human Biomonitoring for Europe (HBM4EU) initiative. Part II, we provide an overview AOP and PBK/D modelling use that improved the selection and interpretation of effect biomarkers. Part III, we describe the collected expertise from the OECD Occupational Biomonitoring subtask effect biomarkers in prioritizing relevant mode of actions (MoAs) and suitable effect biomarkers. Furthermore, we propose a tiered risk assessment approach for occupational biomonitoring. Several effect biomarkers, especially for use in occupational settings, are validated. They offer a direct assessment of the overall health risks associated with exposure to chemicals, chemical mixtures and their transformation products. Promising novel effect biomarkers are emerging for biomonitoring of the general population. Efforts are being dedicated to prioritizing molecular and biochemical effect biomarkers that can provide a causal link in exposure-health outcome associations. This mechanistic approach has great potential in improving human health risk assessment. New techniques such as in silico methods (e.g. QSAR, PBK/D modelling) as well as 'omics data will aid this process. Our multidisciplinary review represents a starting point for enhancing the identification of effect biomarkers and their mechanistic pathways following the AOP framework. This may help in prioritizing the effect biomarker implementation as well as defining threshold limits for chemical mixtures in a more structured way. Several ex vivo biomarkers have been proposed to evaluate combined effects including genotoxicity and xeno-estrogenicity. There is a regulatory need to derive effect-based trigger values using the increasing mechanistic knowledge coming from the AOP framework to address adverse health effects due to exposure to chemical mixtures. Such a mechanistic strategy would reduce the fragmentation observed in different regulations. It could also stimulate a harmonized use of effect biomarkers in a more comparable way, in particular for risk assessments to chemical mixtures.
- Etiology of invasive and subcutaneous fungal infection: Report from the Portuguese laboratory networkPublication . Veríssimo, CristinaThe epidemiology of invasive fungal infections has been changing with the emergence of new etiological agents. In order to better understand the epidemiology of these infections in Portugal, in 2013 the National Network for Laboratory Surveillance of Invasive and Subcutaneous Fungal Infections was made up, comprising 14 hospital laboratories. The following were included for study: i) cases of invasive fungal infection (IFI) by filamentous / dimorphic fungi, ii) cases of probable IFI, according to the criteria established by EORTC / MSG 2008, and iii) cases of subcutaneous fungal infections. Yeast and Pneumocystis jirovecii infections were not included. Participating laboratories ensure the communication of IFI cases to the Reference Laboratory, sending biological or isolated samples, accompanied by a survey containing demographic, laboratory and clinical assessments of patients with suspected fungal infection. Between June 2013 and May 2020, 76 cases were included, distributed as follows: proven IFI (n = 19), subcutaneous infection (excluding endemic fungi) (n = 25); infection by endemic fungi (n = 11), totaling 72.3% of proven deep fungal infections (n = 55), the remaining 27.6% corresponding to probable IFI. It was possible to identify the etiological fungal agent in 96% of the included cases. The genus Aspergillus was the most frequent fungal genera detected being more frequent in the proven and probable IFI. Aseptate fungi of the Mucorales order corresponded to 9.2% of infections, and infections caused by dimorphic endemic fungi represented 14.5% of the total cases. In 10 cases, no positive culture was obtained and the identification of the etiological agent was achieved by panfungal PCR followed by sequencing or though targeted PCR (Aspergillus / Mucorales). Regarding the risk factors for fungal infections, in 81.6% (n=62) of cases, the presence of one or more risk factors for fungal infection was reported. Despite the small number of cases, results allowed perceiving the high diversity of species and the main associated risk factors associated with the diagnosed IFI. Knowledge of the epidemiology of fungal infections is important to improve their diagnosis and treatment.
- Dermatophytosis and terbinafine resistances in PortugalPublication . Henriques, CamilaSuperficial mycoses caused by Trichophyton rubrum are among the most common infections worldwide. In Portugal, it is estimated that 1,510,391 of Portuguese suffer from dermatophytosis, corresponding to an incidence of 14,300 per 1,000,000 inhabitants. In a retrospective analysis carried out from 2014 to 2016, with data collected from various hospital institutions in the North and Center of the country and in the metropolitan area of Lisbon, with the aim of evaluating the etiological agents of superficial mycoses diagnosed at national level, comparing their geographic distribution as well as analyzing the species distribution in relation to the cutaneous area involved, 15 different species of dermatophytes were found, with T. rubrum being the most frequent species (53.6%) and the main etiological agent of dermatophytosis of glabrous skin and feet onychomycosis. Superficial mycoses caused by Trichophyton rubrum are among the most common infections worldwide. T. rubrum infections are difficult to treat and are often associated with recurrences after interruption of the antifungal therapy. Terbinafine is one of the allylamine antifungal agents whose target is squalene epoxidase (SQLE). This agent has been extensively used in the therapy of dermatophyte infections. The emergence of resistance to terbinafine in Trichophyton species (namely T. rubrum) has been described recently. The incidence of patients with tinea pedis or unguium tolerant to terbinafine treatment prompted us to screen the terbinafine resistance of Trichophyton isolates obtained by culture at the Mycology Reference Laboratory of the National Institute of Health Doctor Ricardo Jorge. We aimed to determine the frequency of terbinafine resistance and to identify which mutations were involved and their associated mechanism of resistance. Dermatophytes were identified by culture and MALDI-TOF and/or ITS sequencing. All isolates were grown onto agar supplemented with terbinafine in order to detect potential resistant isolates. Antifungal susceptibility testing was performed following CLSI M38A2 broth microdilution method. Among 102 T. rubrum and 17 of T. interdigitale isolates that were tested, 1 T. rubrum isolate (≈1%) and 3 T. interdigitale isolates (≈18%) showed reduced susceptibility to terbinafine. Overall, three isolates showed high terbinafine resistance (MICs, 4 to ≥ 8mg/L) and one isolate displayed moderate terbinafine resistance (MIC, 1 to 2 mg/L). After antifungal susceptibility testing, we sequenced SQLE gene and only 1 isolate from each species were found to harbor different single point mutations in the SQLE gene , leading to single amino acid substitutions at one position (Phe^397) of the SQLE protein. Taken together, our results prompt the current knowledge about the necessity of antifungal susceptibility testing to select effective strategies for management of clinical cases of dermatophytosis not only in Portugal but worldwide.