Suicide risk after psychiatric discharge: study protocol of a naturalistic, long-term, prospective observational study.

BACKGROUND: Suicide risk of psychiatric patients has proven to be strongly increased in the months after discharge from a psychiatric hospital. Despite this high risk, there is a lack of systematic research on the causes of this elevated suicide risk as well as a lack of treatment and intervention for patients at high risk after discharge. The main objective of this pilot study is, firstly, to examine the factors contributing to the elevated suicide risk and, secondly, to investigate whether an additional setting of care starting at discharge may reduce suicidality. METHODS: In this multi-centre pilot study, treatment as usual is complemented by an additional 18-month post-discharge setting of care for psychiatric patients at high risk for suicide. Two groups of patients differing in the amount of post-discharge personal contacts will be compared. One group of patients will be offered continuous personal contacts after discharge (months 1-6: monthly contacts; months 6-18: every 2 months) while another group of patients will receive contacts only at months 6, 12, and 18 after discharge. Data on suicidality, as well as associated with other symptoms, treatment, and significant events, will be collected. In the case of health-related severe events, the setting of care allows the patient to have the opportunity to connect with the doctor or therapist treating the patient. DISCUSSION: The results of this study will contribute to identifying critical factors raising suicide risk after discharge and will demonstrate the potential influence on suicide prevention of a setting of care with regular personal contact after discharge. TRIAL REGISTRATION: ZMVI1-2517FSB135 - funded by the German Federal Ministry of Health.

In vitro intestinal digestibility of cyclic aromatic polyester oligomers from polyethylene terephthalate (PET) and polybutylene terephthalate (PBT).

Linear and cyclic oligomers are unavoidable non-intentionally added substances (NIAS) present in food contact materials made from common polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyester coatings. Although polyester oligomers can migrate into fats in significant amounts in high-temperature processes such as baking or frying, little is known about their toxicological properties and their behaviour in the human gastrointestinal tract. In the present study, first indications of a possible digestibility of polyester oligomers formed from the commonly used aromatic dicarboxylic acid terephthalic acid (TPA) are provided by in vitro experiments. Three cyclic polyester oligomers originated from PET (trimer) and PBT (dimer and trimer) were extracted from the raw materials, isolated and subjected to a simulated intestinal digestion. A fast cleavage (≥75% of the initial amount) of all three cyclic oligomers into their linear counterparts was detected already within the first hour of in vitro intestinal incubation. Subsequent hydrolysis to shorter chained linear oligomers was determined especially for the PET cyclic trimer. Degradation down to the monomer TPA was not observed. In terms of risk assessment and prioritisation for non-evaluated NIAS, the threshold of toxicological concern (TTC) concept is an appropriate tool. While cyclic polyester oligomers based on TPA are assigned to the TTC Cramer class III (high potential concern, exposure threshold 1.5 µg/kg body weight per day), the corresponding linear oligomers are expected to be of a lower probable toxicological concern (Cramer class I, 30 µg/kg body weight per day). A cleavage of cyclic polyester oligomers under human intestinal conditions, which was assessed to be likely by the provided in vitro experiments, could consequently affect the risk assessment on polyester oligomers.

Learning a locomotor task: with or without errors?

BACKGROUND: Robotic haptic guidance is the most commonly used robotic training strategy to reduce performance errors while training. However, research on motor learning has emphasized that errors are a fundamental neural signal that drive motor adaptation. Thus, researchers have proposed robotic therapy algorithms that amplify movement errors rather than decrease them. However, to date, no study has analyzed with precision which training strategy is the most appropriate to learn an especially simple task. METHODS: In this study, the impact of robotic training strategies that amplify or reduce errors on muscle activation and motor learning of a simple locomotor task was investigated in twenty two healthy subjects. The experiment was conducted with the MAgnetic Resonance COmpatible Stepper (MARCOS) a special robotic device developed for investigations in the MR scanner. The robot moved the dominant leg passively and the subject was requested to actively synchronize the non-dominant leg to achieve an alternating stepping-like movement. Learning with four different training strategies that reduce or amplify errors was evaluated: (i) Haptic guidance: errors were eliminated by passively moving the limbs, (ii) No guidance: no robot disturbances were presented, (iii) Error amplification: existing errors were amplified with repulsive forces, (iv) Noise disturbance: errors were evoked intentionally with a randomly-varying force disturbance on top of the no guidance strategy. Additionally, the activation of four lower limb muscles was measured by the means of surface electromyography (EMG). RESULTS: Strategies that reduce or do not amplify errors limit muscle activation during training and result in poor learning gains. Adding random disturbing forces during training seems to increase attention, and therefore improve motor learning. Error amplification seems to be the most suitable strategy for initially less skilled subjects, perhaps because subjects could better detect their errors and correct them. CONCLUSIONS: Error strategies have a great potential to evoke higher muscle activation and provoke better motor learning of simple tasks. Neuroimaging evaluation of brain regions involved in learning can provide valuable information on observed behavioral outcomes related to learning processes. The impacts of these strategies on neurological patients need further investigations.