Integrating metabolomics profiling measurements across multiple biobanks.

To optimize the quality of large scale mass-spectrometry based metabolomics data obtained from semiquantitative profiling measurements, it is important to use a strategy in which dedicated measurement designs are combined with a strict statistical quality control regime. This assures consistently high-quality results across measurements from individual studies, but semiquantitative data have been so far only comparable for samples measured within the same study. To enable comparability and integration of semiquantitative profiling data from different large scale studies over the time course of years, the measurement and quality control strategy has to be extended. We introduce a strategy to allow the integration of semiquantitative profiling data from different studies. We demonstrate that lipidomics data generated in samples from three different large biobanks acquired in the time course of 3 years can be effectively combined when using an appropriate measurement design and transfer model. This strategy paves the way toward an integrative usage of semiquantitative metabolomics data sets of multiple studies to validate biological findings in another study and/or to increase the statistical power for discovery of biomarkers or pathways by combining studies.

The clinical utility of MRI in patients with neurodevelopmental disorders of unknown origin.

INTRODUCTION: Neuroimaging of the brain in the diagnostic work-up of patients with neurodevelopmental disorders is a matter of continuing debate. Recommendations range from performing brain imaging in all patients with neurodevelopmental disorders to performing an MRI only in those with indication on clinical examinations. Important indications for neuroimaging are head size abnormalities and focal neurological findings. METHODS: Patients with neurodevelopmental disorders of unknown origin (n = 410), referred to a specialized tertiary diagnostic center for neurodevelopmental disorders were included in a retrospective analysis. A 1-day work-up, including an MRI of the brain was performed. Studied were the: (i) yield of MRI scans of the brain and (ii) associations of specific clinical symptoms/signs with abnormal and diagnostic MRI scans. RESULTS: (i) In 30.7% of the 410 patients with neurodevelopmental disorders (n = 126), abnormal MRI scans were observed, leading to an etiological diagnosis in 5.4% of the patients (n = 22). (ii) Pyramidal disorders (P = 0.001), epilepsy (P = 0.04) and an abnormal head circumference (P = 0.02) were associated with an abnormal MRI scan. The presence of one of the following neurological symptoms/signs: movement disorders, pyramidal disorders, epilepsy, or an abnormal head circumference was associated with a diagnostic MRI scan (P < 0.001) (diagnostic MRI % in neurological versus no neurological symptoms/signs, 13.0% versus 1.9%). CONCLUSION: Neuroimaging of the brain in a tertiary care center for patients with neurodevelopmental disorders of unknown origin is useful, especially in case of neurological symptoms/signs.

Cow behaviour on a new grooved floor in comparison with a slatted floor, taking claw health and floor properties into account.

The objective of this study was to compare the behaviour of cows on a grooved floor with that of cows kept on a slatted floor. The trial was carried out with two groups of 12 Holstein-Friesian cows kept in a cowshed with two symmetrical halves, identical except for the floor. One floor was grooved longitudinally to the feeding fence (width of grooves 35mm) and the other was slatted (gaps 35mm wide) perpendicular to the feeding fence. Both floors had scrapers to remove manure. After 3 weeks of being kept on these two floors, cows were switched between floors for 3 weeks. In the third week of each 3-week-period, behavioural observations of cows related to their time budget over 24h, relocation on each floor indicated by index of movement and specific behaviours (aggression, self maintenance) performed on the floors were executed. The health of claws was examined before the trial and 6 weeks later, after the trial. The grooved floor influenced the cows' daily time budget: cows kept on the grooved floor stood less (P<0.05) with four legs inside the cubicles (group 1: 36min, group 2: 39min) than cows kept on the slatted floor (group 1: 57min, group 2: 60min). Neither the specific behaviours of cows nor their movement performed on both floors were different. After switching from the grooved floor to the slatted floor, cows lay for 669min a day (in comparison to 746min a day while kept on the grooved floor, P<0.05) and they stood parallel to the feeding fence for 174min a day (in comparison to 126min a day while kept on the grooved floor, P<0.05). Given that both groups of cows on the grooved floor and the group that began on the slatted floor had a similar daily time budget, it is possible that the different time budget of the remaining group, which started off on the grooved floor, was a reaction (pleasure or disappointment) induced by returning to the familiar floor. The grooved floor was more fouled with faeces (P<0.05) than the slatted floor. The grooved floor can be evaluated as being equal to the slatted floor with a scraper in terms of the behaviour performed on it. There were hardly any slip incidents on it (during 64h of observations, two slip incidents on the grooved floor, four slip incidents on the slatted floor). However, the occurrence of stumble incidents involving the manure scraper (66 cases on the grooved floor and 48 on the slatted floor during 64h of observations) and the occurrence of foot lesions (probably of traumatic origin) suggests that the functioning of the manure scraper, which is indispensable on grooved floors, needs to be optimised.