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The motility of the gastrointestinal tract is crucial for digestive activity and dysfunction can lead to severe disease pattern. A method for analysing the motility is needed when treatment approaches shall be evaluated. Therefore markers attached to different locations on the stomach and the bowel of pigs are video tracked in this research study. The markers are designed to provide a high contrast and have an adhesive side for fixation. Above the operation field a video camera has been placed to film the markers during the procedure. To analyse the video data a special algorithm has been implemented. The algorithm requires a registration process at the beginning of each recording which allows the parallel tracking of multiple markers. After the registration the algorithm tracks the position of the marker frame by frame. Each frame is converted into a greyscale picture by adding specified colour values of each pixel. This allows emphasizing certain colours. The centre of the marker is determined by computing the horizontal and vertical centre of the marker starting at the corresponding marker position of the previous frame. After completion the data is stored as coordinates and a video with the marker position displayed for further processing. For advanced analysis the data can be synchronized with electromyography signals, for example. The marked videos show a promising tracking of the markers. However, if the algorithm loses track of a marker during a recording, it is unlikely to relocate it due to the successive processing of the frames. Nevertheless this method provides a simple and easy to use solution for movement detection of the gastrointestinal tract.

Gastrointestinal (GI) motility disorders are frequent and clinically significant conditions with impairment of patient’s quality of life. Examples range from upper GI symptoms such as dysphagia and gastroparesis to lower GI manifestations, namely chronic-intestinal pseudo obstruction, diarrhea and constipation. Furthermore, postoperative motility disorders are common. Currently, available pharmacological or dietetic treatment options are limited. Since GI motility is based on myoelectric activity, electrical stimulation (ES) is a promising alternative. Numerous studies have demonstrated suitable pacing strategies and parameters in different GI segments. However, results of multilocular ES are rare. We report the first experimental study to evaluate ES of five GI parts in a porcine model. Multi-channel electromyography (EMG) recordings of gastrointestinal baseline and poststimulatory electrical activity were realized together with video-based marker tracking (VBMT). ES provoked visible GI contractions and appeared to modulate frequencies of slow waves and spikes. Further investigations are needed for analysis of locoregional and cross-organ effects of ES on the GI tract.

Background: Mechanical thrombectomy is the standard treatment for acute ischemic stroke in patients with large vessel occlusion and can be performed up to 24h after symptom onset. Despite high recanalization rates, embolism in new territories has been reported in 8.6% of the cases. Causes for this could be clot abruption during stent retrieval into the smaller opening of a standard distal access catheter, and antegrade blood flow via collaterals despite proximal balloon protection. A funnel-shaped tip with a larger internal diameter was developed to increase the rate of first-pass recanalization and to improve the safety and efficacy of mechanical thrombectomy. Methods: This in vitro study compared the efficacy of a funnel-shaped tip with a standard tip in combination with different clot compositions. Mechanical thrombectomy was performed 80 times for each tip, using two stent retrievers (Trevo XP ProVue 3/20 mm, 4/20 mm) and four different clot types (hard vs. soft clots, 0–24h vs. 72h aged clots). Results: Significantly higher first-pass recanalization rates (mTICI 3) were observed for the funnel-shaped tip, 70.0% versus 30.0% for the standard tip (absolute difference, 32; relative difference 57.1%; P <.001), regardless of the clot type and stent retriever. Recanalization could be increased using harder Chandler loop clots versus softer statically generated clots, as well as 0–24h versus 72h aged clots, respectively. Conclusion: The funnel-shaped tip achieved higher first-pass recanalization rates than the smaller standard tip and lower rates of clot abruption at the tip. Clot compositions and aging times impacted recanalization rates. [ABSTRACT FROM AUTHOR]

Introduction Accumulation of amyloid-β (Aβ) in the brain is a key event in Alzheimer's disease (AD) pathogenesis. Recent evidence suggests that in the common sporadic or late-onset forms of AD [...], According to the neurovascular hypothesis, impairment of low-density lipoprotein receptor-related protein-1 (LRP1) in brain capillaries of the blood-brain barrier (BBB) contributes to neurotoxic amyloid-β (Aβ) brain accumulation and drives Alzheimer's disease (AD) pathology. However, due to conflicting reports on the involvement of LRP1 in Aβ transport and the expression of LRP1 in brain endothelium, the role of LRP1 at the BBB is uncertain. As global Lrp1 deletion in mice is lethal, appropriate models to study the function of LRP1 are lacking. Moreover, the relevance of systemic Aβ clearance to AD pathology remains unclear, as no BBB-specific knockout models have been available. Here, we developed transgenic mouse strains that allow for tamoxifen-inducible deletion of Lrp1 specifically within brain endothelial cells ([Slco1c1- CreER.sup.T2] [Lrp1.sup.fl/fl] mice) and used these mice to accurately evaluate LRP1-mediated Aβ BBB clearance in vivo. Selective deletion of Lrp1 in the brain endothelium of C57BL/6 mice strongly reduced brain efflux of injected [[sup.125]I] A[β.sub.1-42]. Additionally, in the 5xFAD mouse model of AD, brain endothelial-specific Lrp1 deletion reduced plasma Aβ levels and elevated soluble brain Aβ, leading to aggravated spatial learning and memory deficits, thus emphasizing the importance of systemic Aβ elimination via the BBB. Together, our results suggest that receptor-mediated Aβ BBB clearance may be a potential target for treatment and prevention of Aβ brain accumulation in AD.

Large animal models of cerebral ischemia have the potential to increase the translational value of stroke research. This study aims to measure early changes of brain tissue oxygen pressure (ptiO 2) and cerebral blood flow (CBF) to characterize a porcine model of sequential middle cerebral artery occlusion (MCAO) and common carotid artery occlusion (CCAO). Eight juvenile German Landrace pigs received unilateral MCAO via a frontotemporal approach under continuous intraparenchymal multiparametric monitoring. Insufficient reduction (i.e., <50% in both ptiO 2 and CBF) was followed by additional bilateral CCAO. Neurodegenerative changes were detected by Fluoro-Jade B (FJB) staining. Only 1 of 8 animals demonstrated a decrease of >50% in both ptiO 2 and CBF after MCAO. Additional CCAO in 7 pigs led to a significant reduction of both ipsilateral and contralateral ptiO 2 (P < 0.01) but not of CBF. There was no difference in ptiO 2 and FJB positive area between hemispheres in this group. Measurement of ptiO 2 correlated negatively with the FJB positive area (P < 0.05). Intraparenchymal multiparametric measurements of acute changes in ptiO 2 and CBF were variable after MCAO. Bilateral CCAO led to a consistent decrease in ptiO 2 and correlated with early degenerative histologic changes, but CBF did not. Real-time procedural ptiO 2 monitoring could provide useful guidance in large animal ischemia models. Feasibility in the context of global cerebral hypoperfusion is demonstrated. [ABSTRACT FROM AUTHOR]

Surgical procedures that induce myocardial ischemia were investigated using spontaneously ventilated and mechanically ventilated rats under sham conditions. All animals were observed for 60 minutes after thoracotomy. Mechanically ventilated animals exhibited a spectrum ranging from hypoxia to hyperoxia. Stable myocardial parameters can be achieved in mechanically ventilated rats at an oxygen application of 30-40% at 90 strokes per minute.