1,118 research outputs found

    Nucleic Acid Lateral Flow Immunoassay for the Detection of Pathogenic Bacteria from Food

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    Nucleic acid lateral flow immunoassay (NALFIA) is a method combining molecular biological principle of detection with immunochemical principle of visualisation. Following isolation of DNA from the sample, a duplex PCR with two primer sets, of which one was labelled with biotin and the other with digoxigenin or fluorescein, respectively, was performed. The PCR solution and carbon particles conjugated with avidin are directly added to the nitrocellulose membrane with two test lines of immobilised antibodies specific for digoxigenin and fluorescein. The appearance of a black line indicates the presence of specific amplicon. We would like to present the NALFIA for the simultaneous detection of L. monocytogenes in particular and the genus Listeria in general, in food. Bacteria from the genus Listeria frequently contaminate a large variety of foods. Occurrence of Listeria strains in food may indicate errors in good hygienic and manufacturing practice, only L. monocytogenes is a significant human and animal pathogen responsible for the serious illness listeriosis. Conventional microbiological methods for L. monocytogenes detection are laborious and take several days to achieve a confirmed identification

    Evidence that bipolar disorder is the poor outcome fraction of a common developmental phenotype: an 8-year cohort study in young people

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    Background Reported rates of bipolar syndromes are highly variable between studies because of age differences, differences in diagnostic criteria, or restriction of sampling to clinical contacts. Method In 1395 adolescents aged 14-17 years, DSM-IV (hypo)manic episodes (manic and hypomanic episodes combined), use of mental health care, and five ordinal subcategories representing the underlying continuous score of (hypo)manic symptoms (‘mania symptom scale') were measured at baseline and approximately 1.5, 4 and 10 years later using the Munich-Composite International Diagnostic Interview (DIA-X/M-CIDI). Results Incidence rates (IRs) of both (hypo)manic episodes and (hypo)manic symptoms (at least one DSM-IV core symptom) were far higher (714/105 person-years and 1720/105 person-years respectively) than traditional estimates. In addition, the risk of developing (hypo)manic episodes was very low after the age of 21 years [hazard ratio (HR) 0.031, 95% confidence interval (CI) 0.0050-0.19], independent of childhood disorders such as attention deficit hyperactivity disorder (ADHD). Most individuals with hypomanic and manic episodes were never in care (87% and 62% respectively) and not presenting co-morbid depressive episodes (69% and 60% respectively). The probability of mental health care increased linearly with the number of symptoms on the mania symptom scale. The incidence of the bipolar categories, in particular at the level of clinical morbidity, was strongly associated with previous childhood disorders and male sex. Conclusions This study showed, for the first time, that experiencing (hypo)manic symptoms is a common adolescent phenomenon that infrequently predicts mental health care use. The findings suggest that the onset of bipolar disorder can be elucidated by studying the pathway from non-pathological behavioural expression to dysfunction and need for car

    A qualitative approach to guide choices for designing a diary study

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    Background: Electronic diaries are increasingly used in diverse disciplines to collect momentary data on experienced feelings, cognitions, behavior and social context in real life situations. Choices to be made for an effective and feasible design are however a challenge. Careful and detailed documentation of argumentation of choosing a particular design, as well as general guidelines on how to design such studies are largely lacking in scientific papers. This qualitative study provides a systematic overview of arguments for choosing a specific diary study design (e.g. time frame) in order to optimize future design decisions. Methods: During the first data assessment round, 47 researchers experienced in diary research from twelve different countries participated. They gave a description of and arguments for choosing their diary design (i.e., study duration, measurement frequency, random or fixed assessment, momentary or retrospective assessment, allowed delay to respond to the beep). During the second round, 38 participants (81%) rated the importance of the different themes identified during the first assessment round for the different diary design topics. Results: The rationales for diary design choices reported during the first round were mostly strongly related to the research question. The rationales were categorized into four overarching themes: nature of the variables, reliability, feasibility, and statistics. During the second round, all overarching themes were considered important for all diary design topics. Conclusions: We conclude that no golden standard for the optimal design of a diary study exists since the design depends heavily upon the research question of the study. The findings of the current study are helpful to explicate and guide the specific choices that have to be made when designing a diary study

    Ethnic differences in calcium, phosphate and bone metabolism

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    The prevalence of osteoporosis and the incidence of age-related fragility fracture vary by ethnicity. There is greater than 10-fold variation in fracture probabilities between countries across the world. Mineral and bone metabolism are intimately interlinked, and both are known to exhibit patterns of daily variation, known as the diurnal rhythm (DR). Ethnic differences are described for Ca and P metabolism. The importance of these differences is described in detail between select ethnic groups, within the USA between African-Americans and White-Americans, between the Gambia and the UK and between China and the UK. Dietary Ca intake is higher in White-Americans compared with African-Americans, and is higher in White-British compared with Gambian and Chinese adults. Differences are observed also for plasma 25-hydroxy vitamin D, related to lifestyle differences, skin pigmentation and skin exposure to UVB-containing sunshine. Higher plasma 1,25-dihydroxy vitamin D and parathyroid hormone are observed in African-American compared with White-American adults. Plasma parathyroid hormone is also higher in Gambian adults and, in winter, in Chinese compared with White-British adults. There may be ethnic differences in the bone resorptive effects of parathyroid hormone, with a relative skeletal resistance to parathyroid hormone observed in some, but not all ethnic groups. Renal mineral excretion is also influenced by ethnicity; urinary Ca (uCa) and urinary P (uP) excretions are lower in African-Americans compared with White-Americans, and in Gambians compared with their White-British counterparts. Little is known about ethnic differences in the DR of Ca and P metabolism, but differences may be expected due to known differences in lifestyle factors, such as dietary intake and sleep/wake pattern. The ethnic-specific DR of Ca and P metabolism may influence the net balance of Ca and P conservation and bone remodelling. These ethnic differences in Ca, P and the bone metabolism may be important factors in the variation in skeletal health

    Depression and sickness behavior are Janus-faced responses to shared inflammatory pathways

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    It is of considerable translational importance whether depression is a form or a consequence of sickness behavior. Sickness behavior is a behavioral complex induced by infections and immune trauma and mediated by pro-inflammatory cytokines. It is an adaptive response that enhances recovery by conserving energy to combat acute inflammation. There are considerable phenomenological similarities between sickness behavior and depression, for example, behavioral inhibition, anorexia and weight loss, and melancholic (anhedonia), physio-somatic (fatigue, hyperalgesia, malaise), anxiety and neurocognitive symptoms. In clinical depression, however, a transition occurs to sensitization of immuno-inflammatory pathways, progressive damage by oxidative and nitrosative stress to lipids, proteins, and DNA, and autoimmune responses directed against self-epitopes. The latter mechanisms are the substrate of a neuroprogressive process, whereby multiple depressive episodes cause neural tissue damage and consequent functional and cognitive sequelae. Thus, shared immuno-inflammatory pathways underpin the physiology of sickness behavior and the pathophysiology of clinical depression explaining their partially overlapping phenomenology. Inflammation may provoke a Janus-faced response with a good, acute side, generating protective inflammation through sickness behavior and a bad, chronic side, for example, clinical depression, a lifelong disorder with positive feedback loops between (neuro)inflammation and (neuro)degenerative processes following less well defined triggers

    Multicentre double-blind placebo-controlled food challenge study in children sensitised to cashew nut

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    Background: Few studies with a limited number of patients have provided indications that cashew-allergic patients may experience severe allergic reactions to minimal amounts of cashew nut. The objectives of this multicentre study were to assess the clinical relevance of cashew nut sensitisation, to study the clinical reaction patterns in double-blind placebo-controlled food challenge tests and to establish the amount of cashew nuts that can elicit an allergic reaction. Methods and Findings: A total of 179 children were included (median age 9.0 years; range 2-17 years) with cashew nut sensitisation an

    Person-Specific Non-shared Environmental Influences in Intra-individual Variability : A Preliminary Case of Daily School Feelings in Monozygotic Twins

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    Most behavioural genetic studies focus on genetic and environmental influences on inter-individual phenotypic differences at the population level. The growing collection of intensive longitudinal data in social and behavioural science offers a unique opportunity to examine genetic and environmental influences on intra-individual phenotypic variability at the individual level. The current study introduces a novel idiographic approach and one novel method to investigate genetic and environmental influences on intra-individual variability by a simple empirical demonstration. Person-specific non-shared environmental influences on intra-individual variability of daily school feelings were estimated using time series data from twenty-one pairs of monozygotic twins (age = 10 years, 16 female pairs) over two consecutive weeks. Results showed substantial inter-individual heterogeneity in person-specific non-shared environmental influences. The current study represents a first step in investigating environmental influences on intra-individual variability with an idiographic approach, and provides implications for future behavioural genetic studies to examine developmental processes from a microscopic angle

    Participation and compliance in a 6-month daily diary study among individuals at risk for mental health problems.

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    Intensive longitudinal (IL)measurement,which involves prolonged self-monitoring, may have important clinical applications but is also burdening. This raises the question who takes part in and successfully completes IL measurements. This preregistered study investigated which demographic, personality, economic, social, psychological, or physical participant characteristics are associated with participation and compliance in an IL study conducted in young adults at enhanced risk for psychopathology. Dutch young adults enrolled in the clinical cohort of the TRacking Adolescents’ Individual Lives Survey (TRAILS) were invited to a 6-month daily diary study. Participant characteristics came from five earlier TRAILS assessment waves collected from Age 11 onwards. To evaluate participation, we compared diary study participants (N =134) to nonparticipants (N =309) and a sex-matched subsample (N = 1926) of individuals from the general population cohort of TRAILS. To evaluate compliance, we analyzed which characteristics were related to the proportion of completed diary entries. We found that participants (23.6 ± 0.7 years old; 57% male) were largely similar to nonparticipants. In addition, compared to the general population, participants reported more negative scores on nearly all characteristics. Internalizing problems predicted higher compliance. Externalizing problems, antisocial behavior, and daily smoking predicted lower compliance. Thus, in at-risk young adults, who scored lower on nearly every positive characteristic and higher on every negative characteristic relative to the general population, participation in a diary study is unbiased. Small biases in compliance occur, of which researchers should be aware. IL measurement is thus suitable in at-risk populations, which is a requirement for its usefulness in clinical practice.</p
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