1,957 research outputs found

    Suggested Improvements for the Allergenicity Assessment of Genetically Modified Plants Used in Foods

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    Genetically modified (GM) plants are increasingly used for food production and industrial applications. As the global population has surpassed 7 billion and per capita consumption rises, food production is challenged by loss of arable land, changing weather patterns, and evolving plant pests and disease. Previous gains in quantity and quality relied on natural or artificial breeding, random mutagenesis, increased pesticide and fertilizer use, and improved farming techniques, all without a formal safety evaluation. However, the direct introduction of novel genes raised questions regarding safety that are being addressed by an evaluation process that considers potential increases in the allergenicity, toxicity, and nutrient availability of foods derived from the GM plants. Opinions vary regarding the adequacy of the assessment, but there is no documented proof of an adverse effect resulting from foods produced from GM plants. This review and opinion discusses current practices and new regulatory demands related to food safety

    3D Slope Stability Analyses of a Complex Formation with a Block-in-Matrix Fabric

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    Heterogeneous rock bodies composed of strong rock blocks surrounded by a weaker finer-grained matrix are often referred to as “BIMrocks” (Block-In-Matrix rocks). These complex formations present a high spatial, dimensional and lithological variability, which makes their characterization an extremely challenging task. As a consequence, geopracticioners have often planned engineering works in bimrocks ignoring the presence of the stronger rock inclusions. However, it is essential that blocks be considered in the analyses in order to obtain reliable results. In fact, rock inclusions strongly affects the strength, deformability and failure surfaces of these geomaterials. In this paper 3D stability analyses are performed with the FLAC 3D code on slope models with variable Volumetric Block Proportions (VBP) to investigate the influence of the rock inclusions on their stability. In order to take the inherent variability of bimrocks into account, a Matlab code was implemented to generate spherical blocks of variable dimensions and locate them randomly within the slope models. Moreover, the stability of a matrix-only slope model is also analyzed by way of comparison. Finally, the paper compares and comments on the results of 2D numerical simulations previously carried out by the author for the same complex block-in-matrix formation

    An Isolated Neurofibromal Polyp of the Colon

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    Solitary neurofibromal colonic polyps are a rare entity, particularly outside the setting of neurofibromatosis type 1. The clinical significance of such lesions has not yet been established. Though typically benign tumors, neurofibromas have been reported to undergo malignant transformation, with an increased risk of malignancy when associated with neurofibromatosis. In this case report, we present the rare case of a man found to have an isolated colonic neurofibroma without any personal/family history or clinical features of neurofibromatosis. A 59-year-old man with a history of dyslipidemia and degenerative joint disease presented for a routine screening colonoscopy. The colonoscopy revealed no abnormalities except a 3 mm transverse colon polyp and another 4 mm polyp in the descending colon. Biopsy results showed the descending colonic polyp to be a tubular adenoma; however, multiple levels of the 3 mm transverse colon polyp revealed interlacing bundles of spindle cells extending into the lamina propria with comma-shaped nuclei consistent with findings seen in neurofibroma. Isolated colonic neurofibromas are rare and understudied. While they are usually benign, they may undergo malignant transformation, especially when associated with neurofibromatosis. Thus, patients presenting with isolated neurofibromas should be followed for development of neurofibromatosis and malignancies

    Determinants of response to a parent questionnaire about development and behaviour in 3 year olds: European multicentre study of congenital toxoplasmosis.

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    Background: We aimed to determine how response to a parent-completed postal questionnaire measuring development, behaviour, impairment, and parental concerns and anxiety, varies in different European centres. Methods: Prospective cohort study of 3 year old children, with and without congenital toxoplasmosis, who were identified by prenatal or neonatal screening for toxoplasmosis in 11 centres in 7 countries. Parents were mailed a questionnaire that comprised all or part of existing validated tools. We determined the effect of characteristics of the centre and child on response, age at questionnaire completion, and response to child drawing tasks. Results: The questionnaire took 21 minutes to complete on average. 67% (714/1058) of parents responded. Few parents (60/1058) refused to participate. The strongest determinants of response were the score for organisational attributes of the study centre (such as direct involvement in follow up and access to an address register), and infection with congenital toxoplasmosis. Age at completion was associated with study centre, presence of neurological abnormalities in early infancy, and duration of prenatal treatment. Completion rates for individual questions exceeded 92% except for child completed drawings of a man (70%), which were completed more by girls, older children, and in certain centres. Conclusion: Differences in response across European centres were predominantly related to the organisation of follow up and access to correct addresses. The questionnaire was acceptable in all six countries and offers a low cost tool for assessing development, behaviour, and parental concerns and anxiety, in multinational studies

    The "Ram Effect": A "Non-Classical" Mechanism for Inducing LH Surges in Sheep

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    During spring sheep do not normally ovulate but exposure to a ram can induce ovulation. In some ewes an LH surge is induced immediately after exposure to a ram thus raising questions about the control of this precocious LH surge. Our first aim was to determine the plasma concentrations of oestradiol (E2) E2 in anoestrous ewes before and after the "ram effect" in ewes that had a "precocious" LH surge (starting within 6 hours), a "normal" surge (between 6 and 28h) and "late» surge (not detected by 56h). In another experiment we tested if a small increase in circulating E2 could induce an LH surge in anoestrus ewes. The concentration of E2 significantly was not different at the time of ram introduction among ewes with the three types of LH surge. "Precocious" LH surges were not preceded by a large increase in E2 unlike "normal" surges and small elevations of circulating E2 alone were unable to induce LH surges. These results show that the "precocious" LH surge was not the result of E2 positive feedback. Our second aim was to test if noradrenaline (NA) is involved in the LH response to the "ram effect". Using double labelling for Fos and tyrosine hydroxylase (TH) we showed that exposure of anoestrous ewes to a ram induced a higher density of cells positive for both in the A1 nucleus and the Locus Coeruleus complex compared to unstimulated controls. Finally, the administration by retrodialysis into the preoptic area, of NA increased the proportion of ewes with an LH response to ram odor whereas treatment with the α1 antagonist Prazosin decreased the LH pulse frequency and amplitude induced by a sexually active ram. Collectively these results suggest that in anoestrous ewes NA is involved in ram-induced LH secretion as observed in other induced ovulators

    Biologic Monitoring of Exposure to Environmental Chemicals throughout the Life Stages: Requirements and Issues for Consideration for the National Children’s Study

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    Biomonitoring of exposure is a useful tool for assessing environmental exposures. The matrices available for analyses include blood, urine, breast milk, adipose tissue, and saliva, among others. The sampling can be staged to represent the particular time period of concern: preconceptionally from both parents, from a pregnant woman during each of the three trimesters, during and immediately after childbirth, from the mother postnatally, and from the child as it develops to 21 years of age. The appropriate sample for biomonitoring will depend upon matrix availability, the time period of concern for a particular exposure or health effect, and the different classes of environmental chemicals to be monitored. This article describes the matrices available for biomonitoring during the life stages being evaluated in the National Children’s Study; the best biologic matrices for exposure assessment for each individual chemical class, including consideration of alternative matrices; the analytical methods used for analysis, including quality control procedures and less costly alternatives; the costs of analysis; optimal storage conditions; and chemical and matrix stability during long-term storage

    Metabolic syndrome in children and adolescents - criteria for diagnosis

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    In recent years, there has been a greater concern about the presence of obesity and metabolic syndrome in children and adolescents. However, there is no consensus regarding the diagnosis of metabolic syndrome in children and adolescents. It is evident that each component of the syndrome must be identified as early as possible in order to prevent definitive lesions. The question is how to do this and which cut-offs must be adopted for this diagnosis. For a matter of convenience, the definition chosen as the most appropriate is the one proposed by the IDF, with cut-offs fixed for pressure, lipids and glycemia, and abdominal circumference points assessed by percentile. Although on the one hand this definition could fail to include some children in the diagnosis of Metabolic Syndrome, on the other hand, it would be of easier acceptance as it does not use multiple tables to assess several anthropometric and metabolic criteria

    Allergenicity assessment of genetically modified crops—what makes sense?

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    GM crops have great potential to improve food quality, increase harvest yields and decrease dependency on certain chemical pesticides. Before entering the market their safety needs to be scrutinized. This includes a detailed analysis of allergenic risks, as the safety of allergic consumers has high priority. However, not all tests currently being applied to assessing allergenicity have a sound scientific basis. Recent events with transgenic crops reveal the fallacy of applying such tests to GM crops

    Value of eight-amino-acid matches in predicting the allergenicity status of proteins: an empirical bioinformatic investigation

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    The use of biotechnological techniques to introduce novel proteins into food crops (transgenic or GM crops) has motivated investigation into the properties of proteins that favor their potential to elicit allergic reactions. As part of the allergenicity assessment, bioinformatic approaches are used to compare the amino-acid sequence of candidate proteins with sequences in a database of known allergens to predict potential cross reactivity between novel food proteins and proteins to which people have become sensitized. Two criteria commonly used for these queries are searches over 80-amino-acid stretches for >35% identity, and searches for 8-amino-acid contiguous matches. We investigated the added value provided by the 8-amino-acid criterion over that provided by the >35%-identity-over-80-amino-acid criterion, by identifying allergens pairs that only met the former criterion, but not the latter criterion. We found that the allergen-sequence pairs only sharing 8-amino-acid identity, but not >35% identity over 80 amino acids, were unlikely to be cross reactive allergens. Thus, the common search for 8-amino-acid identity between novel proteins and known allergens appears to be of little additional value in assessing the potential allergenicity of novel proteins
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