School-based physical activity interventions: which intervention characteristics are associated with participation and retention? A meta-analysis.

OBJECTIVE: Many school-based intervention studies are conducted to increase students' physical activity (PA). Recruitment and retention problems potentially impact the robustness of RCT findings. We conducted a meta-analysis to summarize recruitment and retention rates in long-term secondary school-based PA intervention studies and examined associated participant and intervention characteristics. METHODS: Web of Science, Pubmed, Medline, and PsychInfo were searched until March 20th 2023. We included studies on secondary school-based PA interventions ≥12 weeks, aimed at typically developing adolescents. We abstracted number of schools and students invited, randomized, and participating at follow-up to calculate pooled recruitment and retention rates; participant and intervention characteristics were abstracted to execute subgroup or meta-regression analyses. RESULTS: Recruitment rates were 51% for invited schools and 80% for invited students, the retention for schools was almost 100% and for students 91%. Interventions with fixed and flexible components, executed in Asia and South America, and from later publication years had higher student recruitment rates. Students' retention rates were lower for interventions which had flexible components, were theory/model-based, used an accelerometer, had a longer intervention duration, and included more females. CONCLUSION: Recruitment and retention rates in school-based PA interventions are high. Some participant and intervention characteristics influence these rates: flexibility of the intervention, theory/model-based intervention, accelerometer use, intervention duration, continent, and number of females. Researchers should consider these characteristics in intervention development to achieve optimal balance between intervention effectiveness, recruitment, and retention.

Prediction of the mobility and persistence of eight antibiotics based on soil characteristics.

Antibiotics are widely used in intensive animal husbandry in the Netherlands and are subsequently emitted to soil via manure. To predict degradation and mobility in soil, generic sorption models have been derived. However, most of the coefficients used in generic models are based on a limited range of soils and have not been validated for agricultural soils in the Netherlands. To improve model predictions and assess to what extent differences among soils affect sorption and degradation, an experimental study has been performed. Using a recently developed experimental approach, both the degradation (DT50) and mobility (Kd) of eight selected commonly used antibiotics were determined in 29 typical Dutch agricultural soils. Median DT50 values range from 5.3 days for Sulfadiazine to 120 days for Trimethoprim but are affected by soil type. The ratio of the lowest and highest DT50 for a given antibiotic among soils can be as large as 151, for Tylosin. Measured values of the logKd also range from 0.19 for Sulfadiazine to more than 2 for Doxycycline, Flumequine, Trimethoprim, Tylosin and Enrofloxacine. The impact of soil on Kd is large, especially for more mobile antibiotics such as Sulfadoxine and Sulfadiazine. Both the range in DT50 and Kd can be predicted reasonably well using a Freundlich type regression model that accounts for the variation in soil type and sampling depth. Organic matter, iron oxides, pH and clay content appear to be the main constituents and explain between 29 % (Trimethoprim) and 77 % of the variation in DT50 and between 64 % (Lincomycin) and 87 % (Sulfadoxine and Sulfadiazine) of the variation of Kd. The effect of depth on DT50 and Kd is however limited. The information thus obtained in combination with local data on soil type can be used to more accurately predict the potential risk of relevant antibiotics in soil and transport to ground- and nearby surface waters.

Chemical food safety hazards in circular food systems: a review.

Food production has increasingly become effective but not necessarily sustainable. Transitioning toward circular production systems aiming to minimize waste and reuse materials is one of the means to obtain a more sustainable food production system. However, such a circular food production system can also lead to the accumulation and recirculation of chemical hazards. A literature review was performed to identify potential chemical hazards related to the use of edible and non-edible resources in agriculture and horticulture, and edible plant and animal by-products in feed production. The review revealed that limited information was available on the chemical hazards that could occur when reusing crop residues in circular agriculture. Frequently mentioned hazards present in edible and non-edible resources are heavy metals, process and environmental contaminants, pesticides and pharmaceuticals. For feed, natural toxins and pharmaceutical residues are of potential concern. Studies, furthermore, indicated that plants are capable of taking up chemical hazards when grown on contaminated soil. The presence of chemical hazards in manure, sewage sludge, crop residues, and animal by-products may lead to accumulation in a circular food production system. Therefore, it is relevant to identify these hazards prior to application in food production and, if needed, take precautionary measures to prevent food safety risks.

Review of food safety hazards in circular food systems in Europe.

European food production systems have become very efficient in terms of high yield, quality and safety. However, these production systems are not sustainable since, amongst other reasons, a significant proportion of the production is wasted or lost in the supply chain. One of the strategies of the European Union is to achieve climate neutrality by moving towards a circular economy with better waste management. This includes, reducing food waste and losses, and reusing or recycling by-products of the food and feed production systems. A circular economy would greatly improve the sustainability of the European food systems, but attention must be paid to the emergence of (new) food safety hazards. New or not well-known hazards can occur because by-products are reintroduced into the system or new processing steps are used for recycling, and/or known hazards can accumulate in the food production chain due to the reuse of (by-)products. This review addresses food safety hazards in the circular biobased economy, covering the domains of plant production, animal production, aquaculture, and packaging. Instead of an exhaustive list of all potential hazards, example cases of circular food production systems are given, highlighting the known and potential emerging food safety hazards. Current literature covering emerging food safety hazards in the circular economy shows to be limited. Therefore, more research is needed to identify food safety hazards, to measure the accumulation and the distribution of such hazards in the food and feed production systems, and to develop control and mitigation strategies. We advocate a food safety by design approach.

The analysis of perfluoroalkyl substances at ppt level in milk and egg using UHPLC-MS/MS.

Per- and poly-fluorinated substances (PFASs) are man-made chemicals that have been used for a variety of applications and can end up in the food chain. New opinions on the risk assessment were recently published by the European Food Safety Authority, emphasising the need for more sensitive methods. From this, minimum required LOQs for the analytical method for analysis of milk and egg have been calculated for perfluorooctanoic acid (PFOA) and GenX (hexafluoropropylene oxide dimer acid, HFPO-DA). A fully validated method is described for analysis of 13 PFASs, including PFOA and HFPO-DA, in milk and egg. All compounds, except perfluorodecane sulphonate (PFDS), can be quantitatively determined in these matrices with a trueness ranging from 87% to 119% and a relative within-laboratory reproducibility between 12% and 41%. Also the method proved suitable for confirmation of the identity of the individual PFASs. The LOQ for HFPO-DA in milk and egg is 0.05 ng g-1, well below the calculated required LOQ. For PFOA in egg the determined LOQ is 0.025 ng g-1, nicely below the required level of 0.03 ng g-1. In milk the required LOQ was not achieved: 0.005 instead of 0.003 ng g-1. However, on six out of eight days an LOQ of 0.0025 ng g-1 was demonstrated. It is concluded that the required LOQs are achievable when instrument performance is optimal. The current method can be expanded with long chain PFASs by using a cellulose filter instead of the PTFE filter vials. The presented method was applied for a small-scale study in The Netherlands.

The persistence of a broad range of antibiotics during calve, pig and broiler manure storage.

After administration to livestock, a large fraction of antibiotics are excreted unchanged via excreta and can be transferred to agricultural land. For effective risk assessment a critical factor is to determine which antibiotics can be expected in the different environmental compartments. After excretion, the first relevant compartment is manure storage. In the current study, the fate of a broad scope of antibiotics (n = 46) during manure storage of different livestock animals (calves, pigs, broilers) was investigated. Manure samples were fortified with antibiotics and incubated during 24 days. Analysis was carried out by LC-MS. The dissipation of the antibiotics was modelled based on the recommendations of FOCUS working group. Sulphonamides relatively quickly dissipate in all manure types, with a DT90 of in general between 0.2 and 30 days. Tetracyclines (DT90 up to 422 days), quinolones (DT90 100-5800 days), macrolides (DT90 18-1000 days), lincosamides (DT90 135-1400 days) and pleuromutilins (DT90 of 49-1100 days) are in general much more persistent, but rates depend on the manure type. Specifically lincomycin, pirlimycin, tiamulin and most quinolones are very persistent in manure with more than 10% of the native compound remaining after a year in most manure types. For all compounds tested in the sub-set, except the macrolides, the dissipation was an abiotic process. Based on the persistence and current frequency of use, oxytetracycline, doxycycline, flumequine and tilmicosin can be expected to end up in environmental compartments. Ecotoxicological data should be used to further prioritize these compounds.

Development and validation of a quantitative confirmatory method for 30 ß-lactam antibiotics in bovine muscle using liquid chromatography coupled to tandem mass spectrometry.

A method was developed for the confirmatory and quantitative analysis of 30 ß-lactam antibiotic residues in bovine muscle. The method includes 12 penicillins (amoxicillin, ampicillin, cloxacillin, dicloxacillin, mecillinam, methicillin, nafcillin, oxacillin, penicillin G, penicillin V, piperacillin, ticarcillin), 12 cephalosporins (cefacetrile, cefadroxil, cephalexin, cefalonium, cefazolin, cefoperazone, cefotaxime, cefquinome, cefuroxime, desacetyl cephapirin, desfuroylceftiofur cysteine disulfide, desfuroylceftiofur dimer), five carbapenems (biapenem, doripenem, ertapenem, imipenem, meropenem) and faropenem. Samples were extracted using a simple solvent extraction with acetonitrile:water (80:20, v/v) and C18 dispersive solid-phase extraction (d-SPE) clean-up, followed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) detection. Chromatography was performed on a reversed phase CSH C18 column, using a binary gradient separation comprising of 0.01% formic acid and 0.2mM ammonium acetate in water (mobile phase A) and 0.01% formic acid in acetonitrile (mobile phase B). The mass spectrometer was operated in the positive electrospray ionisation mode (ESI(+)). Validation was performed following the 2002/657/EC guidelines. Trueness ranged between 69% and 143% and precision ranged between 2.0% and 29.9% under within-laboratory reproducibility conditions. The developed method uses minimal sample preparation and 30 test samples can be analysed by a single analyst in a single day. To the best of our knowledge, this is the first method for carbapenems in foodstuff that does not require derivatisation.

Image De-Identification Methods for Clinical Research in the XDS Environment.

To investigate possible de-identification methodologies within the Cross-Enterprise Document Sharing for imaging (XDS-I) environment in order to provide strengthened support for image data exchange as part of clinical research projects. De-identification, using anonymization or pseudonymization, is the most common method to perform information removal within DICOM data. However, it is not a standard part of the XDS-I profiles. Different methodologies were observed to define how and where de-identification should take place within an XDS environment used for scientific research. De-identification service can be placed in three locations within the XDS-I framework: 1) within the Document Source, 2) between the Document Source and Document Consumer, and 3) within the Document Consumer. First method has a potential advantage with respect to the exposure of the images to outside systems but has drawbacks with respect to additional hardware and configuration requirements. Second and third method have big concern in exposing original documents with all identifiable data being intact after leaving the Document Source. De-identification within the Document Source has more advantages compared to the other methods. On the contrary, it is less recommended to perform de-identification within the Document Consumer since it has the highest risk of the exposure of patients identity due to the fact that images are exposed without de-identification during the transfers.

Determination of the stability of antibiotics in matrix and reference solutions using a straightforward procedure applying mass spectrometric detection.

The stability of an antibiotic is a very important characteristic, especially in the field of antibiotic residue analysis. During method development or validation, the stability of the antibiotic has to be demonstrated no matter if the method is used for screening, confirmation, qualitative or quantitative analysis. A procedure for testing the stability of antibiotics in solutions and food samples using LC-MS/MS is described. The procedure is based on the assumption that the antibiotics are stable when stored at -70 °C. Representative solutions or spiked samples containing the antibiotic were stored at the temperature to be tested (-18 or 4 °C) and at -70 °C. After a selected storing time samples were moved from the chosen storage temperature to -70 °C. At the end of the study, all samples--per class of antibiotic--were analysed in one batch. By applying statistical models, it was finally concluded in which circumstances the antibiotic is stable. The stability of 60 antibiotics belonging to the classes of tetracyclines, sulphonamides, quinolones, penicillins, macrolides and aminoglycosides were tested. The stability of solutions containing tetracyclines and penicillins is only guaranteed for 3 months while stored at -18 °C. Solutions of all other antibiotics tested are stable for at least 6 or 12 months when stored at 4 °C. In muscle tissue stored at -18 °C no severe degradation of the tested antibiotics was observed, with the exception of the penicillins. The stability data reported here are useful as a reference for laboratories carrying out validation studies of analytical methods for antibiotic (residue) detection. The data should save the time needed for long-term stability testing of solutions and samples.

Residue analysis of tetracyclines in poultry muscle: shortcomings revealed by a proficiency test.

A proficiency test for tetracycline drug residues in poultry muscle was organized according to the guidelines of International Laboratory Accreditation Cooperation (ILAC) ILAC-G13:2000 (2000). For the proficiency test, three test materials were prepared. The homogeneity and stability of the materials during the study were demonstrated. Sixteen laboratories accepted the invitation to participate in the proficiency test; 11 laboratories reported results within the time frame of the study. Most notably, only four of the participating laboratories complied with the definition of the maximum residue limit (MRL) concerning the inclusion of 4-epimers as stated in European Commission Regulation 281/96 (1996). Most participants reported values for the decision limit (CCalpha) and detection capability (CCbeta) and hence were already in compliance with European Commission 2002/657/EC (2002) for this aspect of method validation. However, some CCalpha and CCbeta values were not in agreement with the actual within-laboratory reproducibility calculated from the results reported in this proficiency test. Although most laboratories obtained satisfactory results, it is clear that an effort is needed to include 4-epiOTC, 4-epiTC and 4-epiCTC in the analytical methods. Moreover, reconsideration of values determined for CCalpha and CCbeta with respect to their accuracy may be necessary in some cases.

Liquid chromatographic-tandem mass spectrometric determination of selected sulphonamides in milk.

Liquid chromatography-tandem mass spectrometry is used for the quantitative analysis of selected sulphonamides in milk. Ultrafiltration is the only sample pre-treatment technique which is required. Consequently, sample throughput is much higher than with conventional procedures, and analyte recoveries are high. As for quantification, both external standard and isotope dilution calibration yield satisfactory results. The method is fully validated for five sulphonamides with a maximum residue limit of 100 microg/kg, and which are included in the Dutch control programme on residues. Furthermore, results are presented on the applicability of the method to detect compounds at a much lower concentration level exemplified by a banned sulphonamide, dapsone, which has a provisional action limit of 5 microg/kg. The main conclusion is that the present, novel approach to the trace-level determination of veterinary drugs is simple and straightforward and has a wide-ranging application potential which is briefly exemplified by the analysis of selected benzimidazoles in milk by essentially the same procedure.

Polymyxin E-1 (colistin sulphate) (neuro-)intoxication in young ostriches ( Struthio camelus spp.).

Colistin (polymyxin E) is a cyclic polypeptide with a potent bactericidal action against most gramnegative bacilli. When used parenterally, polymyxins should be given with great care as they have a very small safety range, and easily induce neurotoxicity and nephrotoxicity. A dose of 39.5mg/kg body weight colistin sulphate injected subcutaneously induced rapid (within 1 to 3 h) mortality in young ostriches. Clinical signs of apathy, lethargy and hypotonia indicative of neurotoxicity of the compound were observed. At postmortem, vascular congestion of brain vessels was seen while, on histology, severe acute oedema was present in the epicardium and the intestinal serosa. Congestion of villi, swelling and vacuolization of the plexus ofAuerbach, as well as intermuscular and perivascular oedema of the heart, were also observed. In view of our observations in ostriches and in other species studied, a dose of >5mg/kg body weight polymyxin E is not considered safe for parenteral administration in ostriches.

[Percutaneous laser disk decompression. Experience since 1989]. / Die perkutane Laserdiskusdekompression (PLDD). Erfahrungen seit 1989.

Since 1987/1988 percutaneous laser disc decompression (PLDD) has been used clinically for treatment of intervertebral disc prolapses. Credible prospective investigations that have been conducted since 1989 with large patient collectives are now available for analysis of their medium-term results and comparison with other minimally invasive procedures. Our follow-up examination of the first 180 patients treated with PLDD from 1989 to 1993 shows a success rate of 72.8%, similar to that with other percutaneous techniques (automated percutaneous lumbar discectomy, percutaneous lumbar discectomy, chemonucleolysis). To guarantee success, the spinal surgeon must have command of the correct technique and also use the appropriate instruments. Good results with the PLDD procedure can be procured when contraindications and indications for patient selection are strictly observed. Overall, our 5 year results seem encouraging.