Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Dermanysuss gallinae attacks humans. Mind the gap!
    Cafiero, Maria Assunta ; Barlaam, Alessandra ; Camarda, Antonio ; Radeski, Miroslav ; Mul, Monique ; Sparagano, Olivier ; Giangaspero, Annunziata - \ 2019
    Avian Pathology 48 (2019)sup1. - ISSN 0307-9457 - p. S22 - S34.
    dermatitis - diagnosis - Europe - future needs - humans - management

    Dermanyssus gallinae is a haematophagous ectoparasite primarily known as a pest of domestic and wild birds. It occasionally feeds on a range of mammals, and, more importantly, is of growing concern in human medicine. This review highlights mite attacks on people working with poultry, and updates the increasing incidence of dermanyssosis in urban environments in Europe. Although several cases of dermanyssosis have been documented, there are a number of reasons why diagnosis of D. gallinae infestations in humans is likely to be underestimated. Firstly, medical specialists are not well aware of D. gallinae infestations in humans. There is also a lack of collaboration with specialists from other disciplines. The problem is compounded by misdiagnoses and by the lack of diagnostic tools. We review the literature on human dermanyssosis cases in Europe, and also provide information on the epidemiology, clinical, histo-pathological and immunological aspects of dermanyssosis. We stress the need for improved recognition of this challenging infestation in humans, and provide straightforward recommendations for health practitioners, starting with collection of the correct anamnestic information and including appropriate management methods for case recognition and resolution. Finally, we indicate the most urgent areas to be addressed by future research. RESEARCH HIGHLIGHTSDermanyssus gallinae is of growing concern in human medicine. Most physicians are not well aware of dermanyssosis in humans. Bio-epidemiological and clinical aspects of this ectoparasitosis are highlighted. Practical key actions for diagnosis and correct management of infestation in humans are provided.

    The relationship between measures of fear of humans and lameness in broiler chicken flocks
    Vasdal, G. ; Moe, R.O. ; Jong, I.C. de; Granquist, E.G. - \ 2018
    Animal 12 (2018)2. - ISSN 1751-7311 - p. 334 - 339.
    broiler - fear - humans - lameness - Welfare Quality
    In the Welfare Quality® assessment protocol for broilers, the touch test is included to assess the human–animal relationship in the flock. The test is designed to measure the animals’ fear of humans, assuming that broilers will withdraw from the observer if they are fearful. However, many broilers close to slaughter age have impaired walking ability, and the results from the touch test may thus be biased by lameness and poor leg health. As the touch test is currently being used in several countries to assess human–animal relationship in broilers, there is an urgent need to examine this potential relationship for a further validation of the test. In the present study, fear of humans was assessed in 50 randomly selected Norwegian broiler flocks, using the touch test as described in the Welfare Quality® protocol for ty broilers. Leg health was assessed by examining the gait of 150 random birds in each of the flocks, using a six-point gait score scale from 0 to 5. The coefficient for the relationship between touch test score and gait score was 0.034 (P<0.001), indicating that the animals express less fear as assessed by the touch test when the gait scores increase. This implies that the touch test may be confounded by impaired walking ability and therefore might be a suboptimal method of assessing fear of humans and human–animal relationship in broilers. In conclusion, the results from this study suggests that the touch test must be further validated in broilers and perhaps be replaced with a fear test that doesn’t rely on walking ability.
    Non-Typhoidal Salmonella Colonization in Chickens and Humans in the Mekong Delta of Vietnam
    Trung, N.V. ; Carrique-Mas, J.J. ; Nghia, N.H. ; Tu, L.T.P. ; Mai, H.H. ; Tuyen, H.T. ; Campbell, J. ; Nhung, N.T. ; Nhung, H.N. ; Minh, P.V. ; Chieu, T.T.B. ; Hieu, T.Q. ; Mai, N.T.N. ; Baker, S. ; Wagenaar, J.A. ; Hoa, N.T. ; Schultsz, C. - \ 2017
    Zoonoses and Public Health 64 (2017)2. - ISSN 1863-1959 - p. 94 - 99.
    antimicrobial resistance - chickens - colonization - humans - Non-typhoidal Salmonella - Vietnam
    Salmonellosis is a public health concern in both the developed and developing countries. Although the majority of human non-typhoidal Salmonella enterica (NTS) cases are the result of foodborne infections or person-to-person transmission, NTS infections may also be acquired by environmental and occupational exposure to animals. While a considerable number of studies have investigated the presence of NTS in farm animals and meat/carcasses, very few studies have investigated the risk of NTS colonization in humans as a result of direct animal exposure. We investigated asymptomatic NTS colonization in 204 backyard chicken farms, 204 farmers and 306 matched individuals not exposed to chicken farming, in southern Vietnam. Pooled chicken faeces, collected using boot or handheld swabs on backyard chicken farms, and rectal swabs from human participants were tested. NTS colonization prevalence was 45.6%, 4.4% and 2.6% for chicken farms, farmers and unexposed individuals, respectively. Our study observed a higher prevalence of NTS colonization among chicken farmers (4.4%) compared with age-, sex- and location- matched rural and urban individuals not exposed to chickens (2.9% and 2.0%). A total of 164 chicken NTS strains and 17 human NTS strains were isolated, and 28 serovars were identified. Salmonella Weltevreden was the predominant serovar in both chickens and humans. NTS isolates showed resistance (20–40%) against tetracycline, chloramphenicol, sulfamethoxazole-trimethoprim and ampicillin. Our study reflects the epidemiology of NTS colonization in chickens and humans in the Mekong delta of Vietnam and emphasizes the need of larger, preferably longitudinal studies to study the transmission dynamics of NTS between and within animal and human host populations.
    Methicillin-resistant Staphylococcus aureus and extended-spectrum and AmpC b-lactamase-producing Escherichia coli in broilers and in people living and/or working on organic broiler farms
    Huijbers, P.M.C. ; Hoek, A.H.A.M. van; Graat, E.A.M. ; Haenen, A.P.J. ; Florijn, A. ; Hengeveld, P.D. ; Duijkeren, E. van - \ 2015
    Veterinary Microbiology 176 (2015)1-2. - ISSN 0378-1135 - p. 120 - 125.
    livestock-associated mrsa - risk-factors - prevalence - netherlands - humans
    The aim of this study was to estimate the prevalence of methicillin-resistantStaphylococcus aureus (MRSA) and extended-spectrum and AmpC b-lactamase (ESBL/AmpC)-producing Escherichia coli among broilers, and humans living and/or working on organic broiler farms; further characterise isolates; and compare these results with those from conventional farms. In the Netherlands, only 9 certified organic broiler farms were present. On 8 of these farms, 60 throat swabs and 20 cloacal swabs were taken per farm for MRSA and ESBL/AmpC-E. coli detection, respectively, at an average age of both 34 (T1) and 68 (T2) days. Faecal swabs and questionnaires were returned by 27 out of 36 humans. For selected ESBL/AmpC-producing E. coli isolates, phylogenetic groups, b-lactamase genes, plasmid families, and sequence types were determined. MRSA was not detected in broiler and human samples. ESBL/AmpC-producing E. coli were isolated from broilers on 7/8 farms at T1 and on all farms at T2. Furthermore, 3 farmers at T1, and 2 farmers and 1 family member at T2 were positive. Genes found in broilers and humans were almost exclusively blaCTX-M-1 and blaCMY-2. Given the high overall human ESBL/AmpC-prevalence (18.5%), which is similar to conventional farms, contact with live broilers is assumed a risk factor for carriage. Farm and sample-level prevalence at T1 are consistent with those from conventional farms. At T2, just before slaughter, sample-level prevalence of ESBL/AmpC-E. coli appears to have decreased (94.3%vs. 80%), which could have important consequences for contamination of retail meat.
    There are no nonresponders to resistance-type exercise training in older men and women
    Churchward-Venne, T.A. ; Tieland, C.A.B. ; Verdijk, L. ; Leenders, M. ; Dirks, M.L. ; Groot, C.P.G.M. de; Loon, L.J.C. van - \ 2015
    Journal of the American Medical Directors Association 16 (2015)5. - ISSN 1525-8610 - p. 400 - 411.
    fiber contractile function - protein supplementation - myofiber hypertrophy - physical-activity - cluster-analysis - elderly-people - muscle size - sarcopenia - strength - humans
    Objective To assess the proposed prevalence of unresponsiveness of older men and women to augment lean body mass, muscle fiber size, muscle strength, and/or physical function following prolonged resistance-type exercise training. Design/Setting/Participants A retrospective analysis of the adaptive response to 12 (n = 110) and 24 (n = 85) weeks of supervised resistance-type exercise training in older (>65 years) men and women. Measurements Lean body mass (DXA), type I and type II muscle fiber size (biopsy), leg strength (1-RM on leg press and leg extension), and physical function (chair-rise time) were assessed at baseline, and after 12 and 24 weeks of resistance-type exercise training. Results Lean body mass increased by 0.9 ± 0.1 kg (range: -3.3 to +5.4 kg; P <.001) from 0 to 12 weeks of training. From 0 to 24 weeks, lean body mass increased by 1.1 ± 0.2 kg (range: -1.8 to +9.2 kg; P <.001). Type I and II muscle fiber size increased by 324 ± 137 µm2 (range: -4458 to +3386 µm2; P = .021), and 701 ± 137 µm2 (range: -4041 to +3904 µm2; P <.001) from 0 to 12 weeks. From 0 to 24 weeks, type I and II muscle fiber size increased by 360 ± 157 µm2 (range: -3531 to +3426 µm2; P = .026) and 779 ± 161 µm2 (range: -2728 to +3815 µm2; P <.001). The 1-RM strength on the leg press and leg extension increased by 33 ± 2 kg (range: -36 to +87 kg; P <.001) and 20 ± 1 kg (range: -22 to +56 kg; P <.001) from 0 to 12 weeks. From 0 to 24 weeks, leg press and leg extension 1-RM increased by 50 ± 3 kg (range: -28 to +145 kg; P <.001) and 29 ± 2 kg (range: -19 to +60 kg; P <.001). Chair-rise time decreased by 1.3 ± 0.4 seconds (range: +21.6 to -12.5 seconds; P = .003) from 0 to 12 weeks. From 0 to 24 weeks, chair-rise time decreased by 2.3 ± 0.4 seconds (range: +10.5 to -23.0 seconds; P <.001). Nonresponsiveness was not apparent in any subject, as a positive adaptive response on at least one training outcome was apparent in every subject. Conclusions A large heterogeneity was apparent in the adaptive response to prolonged resistance-type exercise training when changes in lean body mass, muscle fiber size, strength, and physical function were assessed in older men and women. The level of responsiveness was strongly affected by the duration of the exercise intervention, with more positive responses following more prolonged exercise training. We conclude that there are no nonresponders to the benefits of resistance-type exercise training on lean body mass, fiber size, strength, or function in the older population. Consequently, resistance-type exercise should be promoted without restriction to support healthy aging in the older population.
    Modeling of eating style and its effect on intake
    Boer, J.H.W. van den; Mars, M. - \ 2015
    Appetite 86 (2015). - ISSN 0195-6663 - p. 25 - 30.
    food-intake - social facilitation - behavior - humans - perception - duration - power - size
    Observational research has indicated that modeling of eating style might occur when eating in the presence of an eating companion. This experiment investigated the effect of bite frequency of a same-sex eating companion on bite frequency, meal size and meal duration. A total of 30 normal weight young adults (m/f¿=¿8/22, age: 21.2¿±¿1.9¿years, BMI: 21.2¿±¿1.6¿kg/m2) had three ad libitum meals together with a same-sex confederate (i.e. instructed eating companion). Confederates were instructed to eat at a slow (3¿bites/min), medium (5¿bites/min) or fast (7¿bites/min) bite frequency in randomized order. Eating style was assessed through video registration and weighing left-overs. It was found that the participants' bite frequency was similar during all three conditions, i.e. slow: 3.9¿±¿1.3, medium: 4.0¿±¿1.1, fast: 4.0¿±¿1.3¿bites/min (p¿=¿0.75), as was average bite size (11¿±¿2.6¿g). Time eaten of the participants was shorter in the medium (14.9¿±¿3.6¿min) and fast condition (14.4¿±¿3.7¿min) compared to the slow condition (16.8¿±¿4.8¿min) (post hoc in both cases p¿
    Longer Oral Exposure with Modified Sham Feeding Does Not Slow Down Gastric Emptying of Low- and High-Energy-Dense Gastric Loads in Healthy Young Men
    Wijlens, G.M. ; Erkner, A. ; Mars, M. ; Graaf, C. de - \ 2015
    The Journal of Nutrition 145 (2015)2. - ISSN 0022-3166 - p. 365 - 371.
    food-intake - appetite - stimulation - fat - responses - humans - satiation - ghrelin - liquids - volume
    Background: A long oral exposure to food and a high-energy density of food are shown to increase satiety feelings. The effect of energy density is predominantly caused by an inhibition of gastric emptying. It is hypothesized that prolonging oral exposure may have an additional effect on this inhibition of gastric emptying. However, little human data are available to support this hypothesis. Objective: The objective was to assess the effect of oral exposure duration to food on gastric emptying rate of gastric loads (GLs) low and high in energy density and on satiety feelings. Methods: Twenty-six healthy men (22 ± 3 y, 23 ± 1 kg/m2) participated in a randomized crossover trial with 4 treatments and a control. Treatments consisted of either 1- or 8-min modified sham feeding (MSF) of cake, and a GL of either 100 or 700 kcal infused in the stomach via a nasogastric tube (500 mL, 62.5 mL/min). The control consisted of no MSF and a GL of 500 mL of water. Gastric emptying rate was assessed with a 13C breath test. Breath samples and satiety feelings were collected at fixed time points until 90 min after start of the treatment. Results: Gastric emptying rate and satiety feelings were not affected by duration of MSF (P = 0.27). However, the 700-kcal GL treatments slowed gastric emptying [41% lower area under the curve (AUC)] and increased satiety feelings (22–31% higher AUC) compared with the 100-kcal GL treatments (P <0.001). No interaction between MSF duration and energy density of GL was found (P = 0.44). Conclusions: Higher gastric energy density inhibited gastric emptying and increased satiety feelings in healthy young men. However, prolonging oral exposure to food did not have an additional effect. This study provides more insight in satiety regulation. This trial was registered at as NTR3601.
    Prediction of in vivo developmental toxicity of all-trans-retinoic acid based on in vitro toxicity data and in silico physiologycally based kinetic modeling
    Louisse, J. ; Bosgra, S. ; Blaauboer, B.J. ; Rietjens, I. ; Verwei, M. - \ 2015
    Archives of Toxicology 89 (2015)7. - ISSN 0340-5761 - p. 1135 - 1148.
    dose-dependent kinetics - laboratory-animals - response curves - human liver - rat - metabolism - expression - integration - humans - glucuronidation
    The use of laboratory animals for toxicity testing in chemical safety assessment meets increasing ethical, economic and legislative constraints. The development, validation and application of reliable alternatives for in vivo toxicity testing are therefore urgently needed. In order to use toxicity data obtained from in vitro assays for risk assessment, in vitro concentration–response data need to be translated into in vivo dose–response data that are needed to obtain points of departure for risk assessment, like a benchmark dose (BMD). In the present study, we translated in vitro concentration–response data of the retinoid all-trans-retinoic acid (ATRA), obtained in the differentiation assay of the embryonic stem cell test, into in vivo dose–response data using a physiologically based kinetic model for rat and human that is mainly based on kinetic model parameter values derived using in vitro techniques. The predicted in vivo dose–response data were used for BMD modeling, and the obtained BMDL10 values [lower limit of the 95 % confidence interval on the BMD at which a benchmark response equivalent to a 10 % effect size (BMR10) is reached (BMD10)] for rat were compared with BMDL10 values derived from in vivo developmental toxicity data in rats reported in the literature. The results show that the BMDL10 values from predicted dose–response data differ about sixfold from the BMDL10 values obtained from in vivo data, pointing at the feasibility of using a combined in vitro–in silico approach for defining a point of departure for toxicological risk assessment.
    Emotions on the loose: emotional contagion and the role of oxytocin in pigs
    Reimert, I. ; Bolhuis, J.E. ; Kemp, B. ; Rodenburg, T.B. - \ 2015
    Animal Cognition 18 (2015)2. - ISSN 1435-9448 - p. 517 - 532.
    social cognition - sus-scrofa - behavior - animals - empathy - humans - responses - welfare - slaughter - distress
    We studied emotional contagion, a simple form of empathy, and the role of oxytocin herein in pigs. Two training pigs per pen (n = 16 pens) were subjected to a positive treatment (pairwise access to a large compartment filled with peat, straw and some chocolate raisins) and a negative treatment (social isolation in a small compartment) in a test room using a within-subjects design. Thereafter, two naive pen mates joined the training pigs in the test room, but were not given access to the treatments. This allowed testing for emotional contagion. Subsequently, the naive pigs, serving as their own controls, were given 24 IU of oxytocin or a placebo intranasally 30 min before accompanying the training pigs, which were exposed to either the negative or positive treatment, to the test room. Behavioral differences found between the positive and negative treatments (e.g., play and “tail wagging” vs. standing alert, urinating, defecating and ears backward) show that the treatments induced a positive and negative emotional state in the training pigs, respectively. Changes in behaviors of the training pigs with and without naive pigs present (e.g., in ears backwards) and of the naive pigs with and without training pigs present (e.g., in standing alert) indicated that emotional contagion occurred, especially during the negative treatment. Oxytocin did not seem to affect the behavior of the treated naive pigs, but did affect behaviors (e.g., defecating) of the training pigs which had not received oxytocin. This suggests a role for oxytocin in pig communication, which merits further research.
    Staphylococcus aureus ST398 gene expression profiling during ex vivo colonization of porcine nasal epithelium
    Tulinski, P. ; Duim, B. ; Wittink, F.R. ; Jonker, M.J. ; Breit, T.M. ; Putten, J.P. van; Wagenaar, J.A. ; Fluit, A.C. - \ 2014
    BMC Genomics 15 (2014). - ISSN 1471-2164
    clumping factor-b - methicillin-resistant - carriage - model - adherence - humans - proteinases - determinant - infections - cells
    Background: Staphylococcus aureus is a common human and animal opportunistic pathogen. In humans nasal carriage of S. aureus is a risk factor for various infections. Methicillin-resistant S. aureus ST398 is highly prevalent in pigs in Europe and North America. The mechanism of successful pig colonization by MRSA ST398 is poorly understood. Previously, we developed a nasal colonization model of porcine nasal mucosa explants to identify molecular traits involved in nasal MRSA colonization of pigs. Results: We report the analysis of changes in the transcription of MRSA ST398 strain S0462 during colonization on the explant epithelium. Major regulated genes were encoding metabolic processes and regulation of these genes may represent metabolic adaptation to nasal mucosa explants. Colonization was not accompanied by significant changes in transcripts of the main virulence associated genes or known human colonization factors. Here, we documented regulation of two genes which have potential influence on S. aureus colonization; cysteine extracellular proteinase (scpA) and von Willebrand factor-binding protein (vWbp, encoded on SaPIbov5). Colonization with isogenic-deletion strains (Delta vwbp and Delta scpA) did not alter the ex vivo nasal S. aureus colonization compared to wild type. Conclusions: Our results suggest that nasal colonization with MRSA ST398 is a complex event that is accompanied with changes in bacterial gene expression regulation and metabolic adaptation.
    Of Monkeys and Men: A Metabolomic Analysis of Static and Dynamic Urinary Metabolic Phenotypes in Two Species
    Saccenti, E. ; Tenori, L. ; Verbruggen, P. ; Timmerman, M.E. ; Bouwman, J. ; Greef, J. de; Luchinat, C. ; Smilde, A.K. - \ 2014
    PLoS ONE 9 (2014)9. - ISSN 1932-6203
    multilevel component analysis - time - creatinine - evolution - pathways - humans - diet
    Background Metabolomics has attracted the interest of the medical community for its potential in predicting early derangements from a healthy to a diseased metabolic phenotype. One key issue is the diversity observed in metabolic profiles of different healthy individuals, commonly attributed to the variation of intrinsic (such as (epi)genetic variation, gut microbiota, etc.) and extrinsic factors (such as dietary habits, life-style and environmental conditions). Understanding the relative contributions of these factors is essential to establish the robustness of the healthy individual metabolic phenotype. Methods To assess the relative contribution of intrinsic and extrinsic factors we compared multilevel analysis results obtained from subjects of Homo sapiens and Macaca mulatta, the latter kept in a controlled environment with a standardized diet by making use of previously published data and results. Results We observed similarities for the two species and found the diversity of urinary metabolic phenotypes as identified by nuclear magnetic resonance (NMR) spectroscopy could be ascribed to the complex interplay of intrinsic factors and, to a lesser extent, of extrinsic factors in particular minimizing the role played by diet in shaping the metabolic phenotype. Moreover, we show that despite the standardization of diet as the most relevant extrinsic factor, a clear individual and discriminative metabolic fingerprint also exists for monkeys. We investigate the metabolic phenotype both at the static (i.e., at the level of the average metabolite concentration) and at the dynamic level (i.e., concerning their variation over time), and we show that these two components sum up to the overall phenotype with different relative contributions of about 1/4 and 3/4, respectively, for both species. Finally, we show that the great degree diversity observed in the urinary metabolic phenotype of both species can be attributed to differences in both the static and dynamic part of their phenotype
    Comparison of the chemical composition of three species of smartweed (genus Persicaria) with a focus on drimane sesquiterpenoids
    Prota, N. ; Mumm, R. ; Bouwmeester, H.J. ; Jongsma, M.A. - \ 2014
    Phytochemistry 108 (2014). - ISSN 0031-9422 - p. 129 - 136.
    polygonum genus - antifeedant - flavonoids - humans
    The genus Persicaria is known to include species accumulating drimane sesquiterpenoids, but a comparative analysis highlighting the compositional differences has not been done. In this study, the secondary metabolites of both flowers and leaves of Persicaria hydropiper, Persicaria maculosa and Persicaria minor, three species which occur in the same habitat, were compared. Using gas chromatography–mass spectrometry (GC–MS) analysis of extracts, overall 21/29 identified compounds in extracts were sesquiterpenoids and 5/29 were drimanes. Polygodial was detected in all species, though not in every sample of P. maculosa. On average, P. hydropiper flowers contained about 6.2 mg g FW 1 of polygodial, but P. minor flowers had 200-fold, and P. maculosa 100,000 fold lower concentrations. Comparatively, also other sesquiterpenes were much lower in those species, suggesting the fitness benefit to depend on either investing a lot or not at all in terpenoid-based secondary defences. For P. hydropiper, effects of flower and leaf development and headspace volatiles were analysed as well. The flower stage immediately after fertilisation was the one with the highest content of drimane sesquiterpenoids and leaves contained about 10- fold less of these compounds compared to flowers. The headspace of P. hydropiper contained 8 compounds: one monoterpene, one alkyl aldehyde and six sesquiterpenes, but none were drimanes. The potential ecological significance of the presence or absence of drimane sesquiterpenoids and other metabolites for these plant species are discussed.
    An experimental Toxoplasma gondii dose response challenge model to study therapeutic or vaccine efficacy in cats
    Cornelissen, J.B.W.J. ; Giessen, J.W.B. van der; Takumi, K. ; Teunis, P.F.M. ; Wisselink, H.J. - \ 2014
    PLoS ONE 9 (2014)9. - ISSN 1932-6203 - 9 p.
    crude rhoptry proteins - united-states - tissue cysts - oocysts - bradyzoites - infectivity - tachyzoites - outbreak - animals - humans
    High numbers of Toxoplasma gondii oocysts in the environment are a risk factor to humans. The environmental contamination might be reduced by vaccinating the definitive host, cats. An experimental challenge model is necessary to quantitatively assess the efficacy of a vaccine or drug treatment. Previous studies have indicated that bradyzoites are highly infectious for cats. To infect cats, tissue cysts were isolated from the brains of mice infected with oocysts of T. gondii M4 strain, and bradyzoites were released by pepsin digestion. Free bradyzoites were counted and graded doses (1000, 100, 50, 10), and 250 intact tissue cysts were inoculated orally into three cats each. Oocysts shed by these five groups of cats were collected from faeces by flotation techniques, counted microscopically and estimated by real time PCR. Additionally, the number of T. gondii in heart, tongue and brains were estimated, and serology for anti T. gondii antibodies was performed. A Beta-Poisson dose-response model was used to estimate the infectivity of single bradyzoites and linear regression was used to determine the relation between inoculated dose and numbers of oocyst shed. We found that real time PCR was more sensitive than microscopic detection of oocysts, and oocysts were detected by PCR in faeces of cats fed 10 bradyzoites but by microscopic examination. Real time PCR may only detect fragments of T. gondii DNA without the presence of oocysts in low doses. Prevalence of tissue cysts of T. gondii in tongue, heart and brains, and anti T. gondii antibody concentrations were all found to depend on the inoculated bradyzoite dose. The combination of the experimental challenge model and the dose response analysis provides a suitable reference for quantifying the potential reduction in human health risk due to a treatment of domestic cats by vaccination or by therapeutic drug application.
    Extended-spectrum and AmpC B-lactamase-producing Escherichia coli in broilers and peoplelivingand/or working on broiler farms: prevalence, risk factors and molecular characteristics
    Huijbers, P.M.C. ; Graat, E.A.M. ; Haenen, A.P.J. ; Santen, M.G. van; Essen-Zandbergen, A. van; Mevius, D.J. ; Duijkeren, E. van; Hoek, A.H.A.M. van - \ 2014
    Journal of Antimicrobial Chemotherapy 69 (2014)10. - ISSN 0305-7453 - p. 2669 - 2675.
    livestock-associated mrsa - enterobacteriaceae - netherlands - humans - identification - plasmids - poultry - genes - meat - pcr
    OBJECTIVES: The objectives of this study were to: estimate the prevalence of extended-spectrum ß-lactamase (ESBL)- and AmpC ß-lactamase-producing Escherichia coli carriage among broiler farmers, their family members and employees; identify and quantify risk factors for carriage, with an emphasis on contact with live broilers; and compare isolates from humans and broilers within farms with respect to molecular characteristics to gain insight into transmission routes. METHODS: A cross-sectional prevalence study was conducted on 50 randomly selected Dutch broiler farms. Cloacal swabs were taken from 20 randomly chosen broilers. Faecal swabs were returned by 141 individuals living and/or working on 47 farms. ESBL/AmpC-producing E. coli were isolated and, for selected isolates, phylogenetic groups, plasmids and sequence types were determined. Questionnaires were used for risk factor analysis. RESULTS: All sampled farms were positive, with 96.4% positive pooled broiler samples. The human prevalence was 19.1%, with 14.3% and 27.1% among individuals having a low and a high degree of contact with live broilers, respectively. Five pairs of human-broiler isolates had identical genes, plasmid families and E. coli sequence types, showing clonal transmission. Furthermore, similar ESBL/AmpC genes on the same plasmid families in different E. coli sequence types in humans and broilers hinted at horizontal gene transfer. CONCLUSIONS: The prevalence among people on broiler farms was higher than in previous studies involving patients and the general population. Furthermore, an increased risk of carriage was shown among individuals having a high degree of contact with live broilers. The (relative) contribution of transmission routes that might play a role in the dissemination of ESBL/AmpC-encoding resistance genes to humans on broiler farms should be pursued in future studies.
    A physiologically based kinetic (PBK) model describing plasma concentrations of quercetin and its metabolites in rats
    Boonpawa, R. ; Spenkelink, A. ; Rietjens, I. ; Punt, A. - \ 2014
    Biochemical Pharmacology 89 (2014)2. - ISSN 0006-2952 - p. 287 - 299.
    flavonoid-mediated inhibition - blood partition-coefficients - oral bioavailability - biological-activity - biliary-excretion - intestinal uptake - glucuronidation - humans - absorption - tissues
    Biological activities of flavonoids in vivo are ultimately dependent on the systemic bioavailability of the aglycones as well as their metabolites. In the present study, a physiologically based kinetic (PBK) model was developed to predict plasma concentrations of the flavonoid quercetin and its metabolites and to tentatively identify the regiospecificity of the major circulating metabolites. The model was developed based on in vitro metabolic parameters and by fitting kinetic parameters to literature available in vivo data. Both exposure to quercetin aglycone and to quercetin-4'-O-glucoside, for which in vivo data were available, were simulated. The predicted plasma concentrations of different metabolites adequately matched literature reported plasma concentrations of these metabolites in rats exposed to 4'-O-glucoside. The bioavailability of aglycone was predicted to be very low ranging from 0.004%-0.1% at different oral doses of quercetin or quercetin-4'-O-glucoside. Glucuronidation was a crucial pathway that limited the bioavailability of the aglycone, with 95–99% of the dose being converted to monoglucuronides within 1.5–2.5 h at different dose levels ranging from 0.1 to 50 mg/kg bw quercetin or quercetin-4'-O-glucoside. The fast metabolic conversion to monoglucuronides allowed these metabolites to further conjugate to di- and tri-conjugates. The regiospecificity of major circulating metabolites was observed to be dose-dependent. As we still lack in vivo kinetic data for many flavonoids, the developed model has a great potential to be used as a platform to build PBK models for other flavonoids as well as to predict the kinetics of flavonoids in humans.
    Salivary lipase and a-amylase activities are higher in overweight than in normal weight subjects: Influences on dietary beharior
    Mennella, I. ; Fogliano, V. ; Vitaglione, P. - \ 2014
    Food Research International 66 (2014). - ISSN 0963-9969 - p. 463 - 468.
    alpha-amylase - food-consumption - oral-sensitivity - lingual lipase - fat perception - taste - questionnaire - responses - humans - women
    Mounting evidence shows that hedonic eating, leading to overeating just for pleasure, can be driven by oro-sensory factors through the activation of reward processing and learning in the brain. Foods rich in sugars and fats are potent rewards and saliva composition influences oral taste, texture and aroma perception. A role for salivary a-amylase and lipase in the gustatory system and a link between salivary a-amylase activity and dietary habits were recently hypothesized. The objective of this study was to verify the relationship among salivary lipase and a-amylase activities as well as zinc concentration with food preference and choice of people with different body mass indices. Forty-two (23 normal weight and 19 overweight) healthy subjects participated in the study. Data showed that a-amylase and lipase were 1.8 and 2.4 folds higher in overweight than in normal weight subjects, respectively. On the other hand, overweight subjects showed a 33% reduced salivary zinc concentration compared to normal weight subjects. Only lipase activity positively correlated with individual preference for high-fat foods and with fat content of the diets. All in all data suggested that high salivary lipase activity in overweight subjects could be an adaptive response to the low fat-taste perception related to the reduced zinc concentration. It cannot be ruled out that other factors but diet might influence salivary a-amylase activity in overweight subjects.
    Large inter-individual variation in isoflavone plasma concentration limits use of isoflavone intake data for risk assessement
    Velpen, V. van der; Hollman, P.C.H. ; Nielen, M. van; Schouten, E.G. ; Mensink, M.R. ; Veer, P. van 't; Geelen, A. - \ 2014
    European Journal of Clinical Nutrition 68 (2014). - ISSN 0954-3007 - p. 1141 - 1147.
    randomized controlled-trials - soy isoflavones - premenopausal women - soybean isoflavones - equol production - gut microflora - healthy-adults - habitual diet - bioavailability - humans
    Background/objectives: Isoflavones are present in soy foods and soy-based supplements. Despite low plasma isoflavone concentrations in the general Western population, concentrations in supplement users exceed those suggested to be beneficial for health in Asian populations, raising concerns for adverse effects. To aid risk assessment, quantification of the relation between isoflavone intake and plasma concentrations is essential. Subjects/methods: Plasma samples were collected from postmenopausal women in three placebo-controlled crossover studies with 8-week periods for supplements (two studies, ~100¿mg isoflavones/day, n=88) or 4-week periods for soy foods (one study, ~48¿mg isoflavones/day, n=15). Plasma isoflavone concentrations (daidzein, equol, genistein and glycitein) were quantified using high-performance liquid chromatography and electrochemical detection. The association between plasma concentrations and isoflavone intake, equol producer status, intake–producer interaction and background dietary intake was assessed based on the assumption of a log-linear relation. Results: Median plasma total isoflavone concentrations after the soy food and supplement interventions were respectively 2.16 and 3.47¿µmol/l for equol producers and 1.30 and 2.39¿µmol/l for non-producers. Regression analysis showed that doubling isoflavone intake increased plasma concentrations by 55–62% (±s.e. 1–2%, R2>0.87) for daidzein, genistein, equol (only for producers) and total isoflavones; for glycitein the association was weaker (15±1%, R2=0.48). Adjustments for energy, carbohydrate and fat intake did not affect these estimates. Inter-individual variation, estimated based on repeated measures in one of the studies, was 30–96%. Conclusions: Although the relation between isoflavone intake and plasma concentrations was adequately quantified, the use of isoflavone intake data for risk assessment needs caution due to large inter-individual variation in plasma concentrations.
    Different in the prospective association between individual plasma phospholipid saturated fatty acids and incident type 2 diabetes: the EPIC-InterAct case-cohort study
    Forouhi, N.G. ; Koulman, A. ; Sharp, S.J. ; Groenendijk-van Woudenbergh, G.J. ; Feskens, E.J.M. - \ 2014
    The Lancet Diabetes & Endocrinology 2 (2014)10. - ISSN 2213-8587 - p. 810 - 818.
    dairy product intake - de-novo lipogenesis - risk-factors - dietary - humans - cancer - biomarker - mellitus - disease - project
    Background Conflicting evidence exists regarding the association between saturated fatty acids (SFAs) and type 2 diabetes. In this longitudinal case-cohort study, we aimed to investigate the prospective associations between objectively measured individual plasma phospholipid SFAs and incident type 2 diabetes in EPIC-InterAct participants. Methods The EPIC-InterAct case-cohort study includes 12¿403 people with incident type 2 diabetes and a representative subcohort of 16¿154 individuals who were selected from a cohort of 340¿234 European participants with 3·99 million person-years of follow-up (the EPIC study). Incident type 2 diabetes was ascertained until Dec 31, 2007, by a review of several sources of evidence. Gas chromatography was used to measure the distribution of fatty acids in plasma phospholipids (mol%); samples from people with type 2 diabetes and subcohort participants were processed in a random order by centre, and laboratory staff were masked to participant characteristics. We estimated country-specific hazard ratios (HRs) for associations per SD of each SFA with incident type 2 diabetes using Prentice-weighted Cox regression, which is weighted for case-cohort sampling, and pooled our findings using random-effects meta-analysis. Findings SFAs accounted for 46% of total plasma phospholipid fatty acids. In adjusted analyses, different individual SFAs were associated with incident type 2 diabetes in opposing directions. Even-chain SFAs that were measured (14:0 [myristic acid], 16:0 [palmitic acid], and 18:0 [stearic acid]) were positively associated with incident type 2 diabetes (HR [95% CI] per SD difference: myristic acid 1·15 [95% CI 1·09–1·22], palmitic acid 1·26 [1·15–1·37], and stearic acid 1·06 [1·00–1·13]). By contrast, measured odd-chain SFAs (15:0 [pentadecanoic acid] and 17:0 [heptadecanoic acid]) were inversely associated with incident type 2 diabetes (HR [95% CI] per 1 SD difference: 0·79 [0·73–0·85] for pentadecanoic acid and 0·67 [0·63–0·71] for heptadecanoic acid), as were measured longer-chain SFAs (20:0 [arachidic acid], 22:0 [behenic acid], 23:0 [tricosanoic acid], and 24:0 [lignoceric acid]), with HRs ranging from 0·72 to 0·81 (95% CIs ranging between 0·61 and 0·92). Our findings were robust to a range of sensitivity analyses. Interpretation Different individual plasma phospholipid SFAs were associated with incident type 2 diabetes in opposite directions, which suggests that SFAs are not homogeneous in their effects. Our findings emphasise the importance of the recognition of subtypes of these fatty acids. An improved understanding of differences in sources of individual SFAs from dietary intake versus endogenous metabolism is needed. Funding EU FP6 programme, Medical Research Council Epidemiology Unit, Medical Research Council Human Nutrition Research, and Cambridge Lipidomics Biomarker Research Initiative.
    Sensory-specific appetite is affected by actively smelled food odors and remains stable over time in normal-wight women
    Ramaekers, M.G. ; Boesveldt, S. ; Lakemond, C.M.M. ; Boekel, M.A.J.S. van; Luning, P.A. - \ 2014
    The Journal of Nutrition 144 (2014)8. - ISSN 0022-3166 - p. 1314 - 1319.
    cephalic phase responses - cue exposure - unrestrained eaters - olfactory-bulb - chewing gum - satiety - hunger - humans - perception - attention
    Understanding overconsumption starts with knowledge of how separate factors influence our eating behavior. Food cues such as food odors are known for their effect on general appetite and sensory-specific appetite (SSA). Active sniffing rather than passive exposure may induce satiation over time. The objective of this study was to investigate how actively sniffing banana odors affects general appetite, SSA, and subsequent food intake. In a crossover study, 61 women actively smelled cups containing natural banana, artificial banana odor, or water (no odor) for 10 min. Treatment order was randomly assigned as much as possible. General appetite and SSA were monitored by using 100-mm visual analog scales during the 10 min of active sniffing, followed by ad libitum intake of banana milkshake. Results showed that SSA was consistently high (+12 mm) during actively sniffing natural or artificial banana odors, with no decrease in SSA over time. Sniffing both banana odors increased the appetite for banana (+11 mm) and other sweet products (+4 mm), whereas the appetite for savory products decreased by 7 mm (all P <0.01) compared with no odor. Actively sniffing banana odor did not significantly influence food intake (P = 0.68) or general appetite scores (P = 0.06). In conclusion, SSA scores during active sniffing were identical to the SSA found in a similar study that used passive smelling, suggesting that SSA is independent of the manner of sniffing and exposure time. Moreover, sweet/savory categorization may suggest that food odors communicate information about the nutrient composition of their associated foods. These data clearly show the appetizing effects of food odors.
    Food preference and intake in response to ambient odours in overweight and normal-weight females
    Zoon, H.F.A. ; He, W. ; Wijk, R.A. de; Graaf, C. de; Boesveldt, S. - \ 2014
    Physiology and Behavior 133 (2014). - ISSN 0031-9384 - p. 190 - 196.
    cephalic phase responses - cue exposure - unrestrained eaters - eating behavior - external cues - appetite - humans - perception - obesity - brain
    In our food abundant environment, food cues play an important role in the regulation of energy intake. Odours can be considered as external cues that can signal energy content in the anticipatory phase of eating. This study aims to determine whether exposure to olfactory cues associated with energy dense foods leads to increased food intake and greater preference for energy-dense foods. In addition, we assessed whether BMI and hunger state modulated this effect. Twenty-five overweight (mean BMI: 31.3 kg/m2, S.E.: 0.6) and 25 normal-weight (mean BMI: 21.9 kg/m2, S.E.: 0.4) females, matched on age and restraint score, participated. In 6 separate sessions they were exposed to odours of three different categories (signalling non-food, high-energy food and low-energy food) in two motivational states (hungry and satiated). After 10 min of exposure food preference was assessed with a computerized two-item forced choice task and after 20 min a Bogus Taste Test was used to determine energy intake (kcal and g). In a hungry state, the participants ate more (p <.001) and preferred high-energy products significantly more often (p <.001) when compared to the satiated state. A trend finding for the interaction between hunger and BMI suggested that the food preference of overweight participants was less affected by their internal state (p = .068). Neither energy intake (kcal: p = .553; g: p = .683) nor food preference (p = .280) was influenced by ambient exposure to odours signalling different categories. Future studies need to explore whether food odours can indeed induce overeating. More insight is needed regarding the possible influence of context (e.g. short exposure duration, large variety of food) and personality traits (e.g. restraint, impulsive) on odour-induced overeating.
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