Modeling Stroke in Mice: Permanent Coagulation of the Distal Middle Cerebral Artery

Stroke is the third most common cause of death and a main cause of acquired adult disability in developed countries. Only very limited therapeutical ...

University Hospital Munich

Munich Cluster for Systems Neurology (SyNergy)

Testicular intraepithelial neoplasia (TIN) of the testis is the noninvasive precursor of testicular germ cell tumours (GCT) and can be detected by a single random biopsy in 5% of patients with GCT in the contralateral testes. Although it is generally presumed that TIN is dispersed throughout the testis, we realize in about 60% of TIN bearing tissue close to testis tumours that its distribution is not homogenously diffuse, but may be focal. Thus we tested whether we can improve diagnostic safety in detecting TIN by increasing the number of biopsies. We could finally evaluate 295 men with proven testicular tumours. Three biopsies of contralateral testes were taken (each 5 mm length) from one surgical incision site and fixed in Bouin's solution or glutaraldehyde. TIN cells were histologically identified by their typical morphological characteristics and additionally by placental alkaline phophatase (PlAP) immunohistochemistry. Patients revealed testicular tumour without contralateral TIN in 271 cases and with contralateral TIN in 24 cases (8.1%). In 6 of these 24 men with contralateral TIN the cells could be detected in only one (n=5) or two (n=1) of the three specimen investigated. That means in these six patients TIN could have been missed if only one single random biopsy was taken. By increasing the number of biopsies (=increasing the number of investigated seminiferous tubules) the detection rate of contralateral TIN may be increased up to 8.1%. Thus we recommend multiple testicular biopsies to increase the diagnostic safety in detection of TIN. Biopsies may be taken from one randomly chosen surgical incision site.

Update on the diagnostic safety for detection of testicular intraepithelial neoplasia (TIN).

Impaired bone metabolism following urinary diversion through intestinal segments has always been a controversial subject of unclear clinical relevance. Whereas the perpetuated pathophysiological considerations seem conclusive in theory, the role of acidosis and malabsorption is less clear in animal experimentation and, even more so, in the clinical reality of modern continent diversion. In hardly any of the available contemporary case series was overt derangement of the acid-base balance, rickets or osteomalacia encountered. No consistent changes in osteotropic serum parameters could be found with normal calcium and phosphate in all patients. The assumption that colonic reservoirs have a higher risk of developing metabolic bone disease could not be confirmed by clinical data. As early correction of base excess is easy and probably a common policy in patients with intestinal urinary reservoirs, it will be virtually impossible to further study the natural history of bone metabolism after urinary diversion. While there is no need for a bone specific follow-up in asymptomatic adults with a normal acid-base balance, particular attention should be paid to children and to all patients with impaired renal function.

Bladder, bowel and bones--skeletal changes after intestinal urinary diversion.

Ambident reactivity of the nitrite ion revisited.

The covariance matrix adaptation evolution strategy (CMA-ES) is one of the most powerful evolutionary algorithms for real-valued single-objective optimization. In this paper, we develop a variant of the CMA-ES for multi-objective optimization (MOO). We first introduce a single-objective, elitist CMA-ES using plus-selection and step size control based on a success rule. This algorithm is compared to the standard CMA-ES. The elitist CMA-ES turns out to be slightly faster on unimodal functions, but is more prone to getting stuck in sub-optimal local minima. In the new multi-objective CMAES (MO-CMA-ES) a population of individuals that adapt their search strategy as in the elitist CMA-ES is maintained. These are subject to multi-objective selection. The selection is based on non-dominated sorting using either the crowding-distance or the contributing hypervolume as second sorting criterion. Both the elitist single-objective CMA-ES and the MO-CMA-ES inherit important invariance properties, in particular invariance against rotation of the search space, from the original CMA-ES. The benefits of the new MO-CMA-ES in comparison to the well-known NSGA-II and to NSDE, a multi-objective differential evolution algorithm, are experimentally shown.

Covariance matrix adaptation for multi-objective optimization.

Morphological changes in preterm infants with bronchopulmonary dysplasia (BPD) have functional consequences on lung volume, ventilation inhomogeneity and respiratory mechanics. Although some studies have shown lower lung volumes and increased ventilation inhomogeneity in BPD infants, conflicting results exist possibly due to differences in sedation and measurement techniques.

Lung volume, breathing pattern and ventilation inhomogeneity in preterm and term infants.

Physiological polyamines are required in various biological processes. In the current study, we used norspermidine, a structural analog of the natural polyamine spermidine, to investigate polyamine uptake in the model organism Caenorhabditis elegans. Norspermidine was found to have two remarkable effects: it is toxic for the nematode, without affecting its food, Escherichia coli; and it hampers RNA interference. By characterizing a norspermidine-resistant C. elegans mutant strain that has been isolated in a genetic screen, we demonstrate that both effects, as well as the uptake of a fluorescent polyamine-conjugate, depend on the transporter protein CATP-5, a novel P(5B)-type ATPase. To our knowledge, CATP-5 represents the first P(5)-type ATPase that is associated with the plasma membrane, being expressed in the apical membrane of intestinal cells and the excretory cell. Moreover, genetic interaction studies using C. elegans polyamine synthesis mutants indicate that CATP-5 has a function redundant to polyamine synthesis and link reduced polyamine levels to retarded postembryonic development, reduced brood size, shortened life span, and small body size. We suggest that CATP-5 represents a crucial component of the pharmacologically important polyamine transport system, the molecular nature of which has not been identified so far in metazoa.

Caenorhabditis elegans P5B-type ATPase CATP-5 operates in polyamine transport and is crucial for norspermidine-mediated suppression of RNA interference.

The efficient application of graph cuts to Markov Random Fields (MRFs) with multiple discrete or continuous labels remains an open question. In this paper, we demonstrate one possible way of achieving this by using graph cuts to combine pairs of suboptimal labelings or solutions. We call this combination process the fusion move. By employing recently developed graph-cut-based algorithms (so-called QPBO-graph cut), the fusion move can efficiently combine two proposal labelings in a theoretically sound way, which is in practice often globally optimal. We demonstrate that fusion moves generalize many previous graph-cut approaches, which allows them to be used as building blocks within a broader variety of optimization schemes than were considered before. In particular, we propose new optimization schemes for computer vision MRFs with applications to image restoration, stereo, and optical flow, among others. Within these schemes the fusion moves are used 1) for the parallelization of MRF optimization into several threads, 2) for fast MRF optimization by combining cheap-to-compute solutions, and 3) for the optimization of highly nonconvex continuous-labeled MRFs with 2D labels. Our final example is a nonvision MRF concerned with cartographic label placement, where fusion moves can be used to improve the performance of a standard inference method (loopy belief propagation).

Fusion moves for Markov random field optimization.

Following recent advances in detection, context modeling, and tracking, scene understanding has been the focus of renewed interest in computer vision research. This paper presents a novel probabilistic 3D scene model that integrates state-of-the-art multiclass object detection, object tracking and scene labeling together with geometric 3D reasoning. Our model is able to represent complex object interactions such as inter-object occlusion, physical exclusion between objects, and geometric context. Inference in this model allows us to jointly recover the 3D scene context and perform 3D multi-object tracking from a mobile observer, for objects of multiple categories, using only monocular video as input. Contrary to many other approaches, our system performs explicit occlusion reasoning and is therefore capable of tracking objects that are partially occluded for extended periods of time, or objects that have never been observed to their full extent. In addition, we show that a joint scene tracklet model for the evidence collected over multiple frames substantially improves performance. The approach is evaluated for different types of challenging onboard sequences. We first show a substantial improvement to the state of the art in 3D multipeople tracking. Moreover, a similar performance gain is achieved for multiclass 3D tracking of cars and trucks on a challenging dataset.

Monocular visual scene understanding: understanding multi-object traffic scenes.

Many recent advances in multiple target tracking aim at finding a (nearly) optimal set of trajectories within a temporal window. To handle the large space of possible trajectory hypotheses, it is typically reduced to a finite set by some form of data-driven or regular discretization. In this work we propose an alternative formulation of multi-target tracking as minimization of a continuous energy. Contrary to recent approaches, we focus on designing an energy that corresponds to a more complete representation of the problem, rather than one that is amenable to global optimization. Besides the image evidence, the energy function takes into account physical constraints, such as target dynamics, mutual exclusion, and track persistence. In addition, partial image evidence is handled with explicit occlusion reasoning, and different targets are disambiguated with an appearance model. To nevertheless find strong local minima of the proposed non-convex energy we construct a suitable optimization scheme that alternates between continuous conjugate gradient descent and discrete trans-dimensional jump moves. These moves, which are executed such that they always reduce the energy, allow the search to escape weak minima and explore a much larger portion of the search space of varying dimensionality. We demonstrate the validity of our approach with an extensive quantitative evaluation on several public datasets.

Continuous Energy Minimization for Multi-Target Tracking.

Many recent advances in multiple target tracking aim at finding a (nearly) optimal set of trajectories within a temporal window. To handle the large space of possible trajectory hypotheses, it is typically reduced to a finite set by some form of data-driven or regular discretization. In this work, we propose an alternative formulation of multitarget tracking as minimization of a continuous energy. Contrary to recent approaches, we focus on designing an energy that corresponds to a more complete representation of the problem, rather than one that is amenable to global optimization. Besides the image evidence, the energy function takes into account physical constraints, such as target dynamics, mutual exclusion, and track persistence. In addition, partial image evidence is handled with explicit occlusion reasoning, and different targets are disambiguated with an appearance model. To nevertheless find strong local minima of the proposed nonconvex energy, we construct a suitable optimization scheme that alternates between continuous conjugate gradient descent and discrete transdimensional jump moves. These moves, which are executed such that they always reduce the energy, allow the search to escape weak minima and explore a much larger portion of the search space of varying dimensionality. We demonstrate the validity of our approach with an extensive quantitative evaluation on several public data sets.

Stefan Roth

Institute for Stroke and Dementia Research

University Hospital Munich

Modeling Stroke in Mice: Permanent Coagulation of the Distal Middle Cerebral Artery

Stefan Roth

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Institute for Stroke and Dementia Research

University Hospital Munich

Modeling Stroke in Mice: Permanent Coagulation of the Distal Middle Cerebral Artery

Institute for Stroke and Dementia Research