Ceftriaxone-induced neutropenia successfully overcome by a switch to penicillin G in Cardiobacterium hominis endocarditis.

Leukopenia, including agranulocytosis, is a severe complication of treatment with all ß-lactam antibiotics. Its incidence increases with age. Cardiobacterium hominis endocarditis after implantation of an aortic valve bio-prosthesis in a 77-year-old woman was treated with ceftriaxone 2 g/day plus gentamicin 160 mg/day intravenously. On Day 25 of treatment, blood leukocytes had decreased to 1800/µl (neutrophils 370/µl). Antibiotic therapy was switched to penicillin G 20 million international units (IU)/day. Thereafter, blood leukocytes including neutrophils normalized suggesting that penicillin G was less bone marrow-toxic than ceftriaxone. High-dose ciprofloxacin, the alternative to penicillin G, was avoided because of the risk of cognitive and behavioral side effects. The present case suggests that with close laboratory monitoring a ß-lactam with differing side chains should not be considered contraindicated after ß-lactam antibiotic-induced neutropenia.

Dysphagia in amyotrophic lateral sclerosis: Quantification of bulbar motor dysfunction.

BACKGROUND: Dysphagia as a sequel and possible early sign of amyotrophic lateral sclerosis (ALS) is caused by progressive impaired bulbar motor function. OBJECTIVE: To evaluate bulbar motor dysfunction in patients suffering from ALS compared to a healthy reference group. METHODS: A clinical study and prospective group comparison was designed. Patients and healthy volunteers were examined in the outpatient clinic of our university medical center. Ten patients with ALS and 20 healthy volunteers were included. All participants underwent a flexible endoscopic evaluation of swallowing (FEES) and a manometric measurement of the maximal sub-palatal atmospheric pressure generated by suction as well as of the prevalent pressure during swallowing. Additionally, the Sydney Swallow Questionnaire (SSQ) was completed by all participants to score the self-rated extent of dysphagia. RESULTS: Comparing maximal suction pressures, the group of patients showed significantly lower values (p < .001). There was a significant correlation between reduced pressures and the degree of dysphagia (SSQ score) (r = -0.73). CONCLUSIONS: As the oral cavity is an easily accessible compartment of the upper digestive tract, manometric measurements might serve as a simple instrument in order to detect or to monitor bulbar motor dysfunction. Oral manometry may facilitate early detection and monitoring of dysphagia in ALS. Larger studies are required to confirm our findings.

Quantum Anomalous Hall Effects in Graphene from Proximity-Induced Uniform and Staggered Spin-Orbit and Exchange Coupling.

We investigate an effective model of proximity modified graphene (or symmetrylike materials) with broken time-reversal symmetry. We predict the appearance of quantum anomalous Hall phases by computing bulk band gap and Chern numbers for benchmark combinations of system parameters. Allowing for staggered exchange field enables quantum anomalous Hall effect in flat graphene with Chern number C=1. We explicitly show edge states in zigzag and armchair nanoribbons and explore their localization behavior. Remarkably, the combination of staggered intrinsic spin-orbit and uniform exchange coupling gives topologically protected (unlike in time-reversal systems) pseudohelical states, whose spin is opposite in opposite zigzag edges. Rotating the magnetization from out of plane to in plane makes the system trivial, allowing us to control topological phase transitions. We also propose, using density functional theory, a material platform-graphene on Ising antiferromagnet MnPSe_{3}-to realize staggered exchange (pseudospin Zeeman) coupling.

Cav2.3 channels contribute to dopaminergic neuron loss in a model of Parkinson's disease.

Degeneration of dopaminergic neurons in the substantia nigra causes the motor symptoms of Parkinson's disease. The mechanisms underlying this age-dependent and region-selective neurodegeneration remain unclear. Here we identify Cav2.3 channels as regulators of nigral neuronal viability. Cav2.3 transcripts were more abundant than other voltage-gated Ca2+ channels in mouse nigral neurons and upregulated during aging. Plasmalemmal Cav2.3 protein was higher than in dopaminergic neurons of the ventral tegmental area, which do not degenerate in Parkinson's disease. Cav2.3 knockout reduced activity-associated nigral somatic Ca2+ signals and Ca2+-dependent after-hyperpolarizations, and afforded full protection from degeneration in vivo in a neurotoxin Parkinson's mouse model. Cav2.3 deficiency upregulated transcripts for NCS-1, a Ca2+-binding protein implicated in neuroprotection. Conversely, NCS-1 knockout exacerbated nigral neurodegeneration and downregulated Cav2.3. Moreover, NCS-1 levels were reduced in a human iPSC-model of familial Parkinson's. Thus, Cav2.3 and NCS-1 may constitute potential therapeutic targets for combatting Ca2+-dependent neurodegeneration in Parkinson's disease.

Protected Pseudohelical Edge States in Z_{2}-Trivial Proximitized Graphene.

We investigate topological properties of models that describe graphene on realistic substrates which induce proximity spin-orbit coupling in graphene. A Z_{2} phase diagram is calculated for the parameter space of (generally different) intrinsic spin-orbit coupling on the two graphene sublattices, in the presence of Rashba coupling. The most fascinating case is that of staggered intrinsic spin-orbit coupling which, despite being topologically trivial, Z_{2}=0, does exhibit edge states protected by time-reversal symmetry for zigzag ribbons as wide as micrometers. We call these states pseudohelical as their helicity is locked to the sublattice. The spin character and robustness of the pseudohelical modes is best exhibited on a finite flake, which shows that the edge states have zero g factor, carry a pure spin current in the cross section of the flake, and exhibit spin-flip reflectionless tunneling at the armchair edges.

ROS-IGTL-Bridge: an open network interface for image-guided therapy using the ROS environment.

PURPOSE: With the growing interest in advanced image-guidance for surgical robot systems, rapid integration and testing of robotic devices and medical image computing software are becoming essential in the research and development. Maximizing the use of existing engineering resources built on widely accepted platforms in different fields, such as robot operating system (ROS) in robotics and 3D Slicer in medical image computing could simplify these tasks. We propose a new open network bridge interface integrated in ROS to ensure seamless cross-platform data sharing. METHODS: A ROS node named ROS-IGTL-Bridge was implemented. It establishes a TCP/IP network connection between the ROS environment and external medical image computing software using the OpenIGTLink protocol. The node exports ROS messages to the external software over the network and vice versa simultaneously, allowing seamless and transparent data sharing between the ROS-based devices and the medical image computing platforms. RESULTS: Performance tests demonstrated that the bridge could stream transforms, strings, points, and images at 30 fps in both directions successfully. The data transfer latency was <1.2 ms for transforms, strings and points, and 25.2 ms for color VGA images. A separate test also demonstrated that the bridge could achieve 900 fps for transforms. Additionally, the bridge was demonstrated in two representative systems: a mock image-guided surgical robot setup consisting of 3D slicer, and Lego Mindstorms with ROS as a prototyping and educational platform for IGT research; and the smart tissue autonomous robot surgical setup with 3D Slicer. CONCLUSION: The study demonstrated that the bridge enabled cross-platform data sharing between ROS and medical image computing software. This will allow rapid and seamless integration of advanced image-based planning/navigation offered by the medical image computing software such as 3D Slicer into ROS-based surgical robot systems.

Transcranial doppler sonography is not a valid diagnostic tool for detection of basilar artery stenosis or in-stent restenosis: a retrospective diagnostic study.

BACKGROUND: There are contradictory reports concerning the validity of transcranial sonography (TCD and TCCS) for examinations of the basilar artery. Here we investigated sensitivity and specificity of transcranial sonography for the detection of basilar artery stenosis and in-stent-restenosis compared to cerebral angiography. METHODS: We analyzed data of 104 examinations of the basilar artery. The association between sonographic peak systolic velocity (PSV) and degree of stenosis obtained by cerebral angiography was evaluated applying Spearman's correlation coefficient. Receiver Operating Characteristics (ROC) curves and areas under the curve (AUC) were calculated for the detection of a ≥50% stenosis defined by angiography. Optimal cut-off was derived using the Youden-index. RESULTS: A weak but statistically significant correlation between PSV and the degree of stenosis was found (n=104, rho=0.35, p<0.001). ROC analysis for a detection of ≥50% stenosis showed an AUC of 0.70, a sensitivity of 74.0% and a specificity of 65.0% at the optimal cut off of 124 cm/s. Results were consistent when analyzing examinations done in stented and unstented arteries separately (TCD VS DSA/CTA in unstented artery: AUC=0.66, sensitivity 61.0%, specificity 65.0%, TCD/TCCS VS DSA in stented artery: AUC=0.63, sensitivity 71.0%, specificity 82.0%). Comparing TCCS measurements exclusively to angiography, ROC analysis showed an AUC of 1.00 for the detection of an in-stent-restenosis ≥50% with a sensitivity and specificity of 100% when a PSV of 132 cm/s was used as a cut off value. CONCLUSION: Validity of TCD in the assessment of basilar artery stenosis or in-stent restenosis is poor. First results for TCCS are promising, but due to the small samplesize further studies with larger samples sizes are warranted.

Femtosecond photo-switching of interface polaritons in black phosphorus heterostructures.

The possibility of hybridizing collective electronic motion with mid-infrared light to form surface polaritons has made van der Waals layered materials a versatile platform for extreme light confinement and tailored nanophotonics. Graphene and its heterostructures have attracted particular attention because the absence of an energy gap allows plasmon polaritons to be tuned continuously. Here, we introduce black phosphorus as a promising new material in surface polaritonics that features key advantages for ultrafast switching. Unlike graphene, black phosphorus is a van der Waals bonded semiconductor, which enables high-contrast interband excitation of electron-hole pairs by ultrashort near-infrared pulses. Here, we design a SiO2/black phosphorus/SiO2 heterostructure in which the surface phonon modes of the SiO2 layers hybridize with surface plasmon modes in black phosphorus that can be activated by photo-induced interband excitation. Within the Reststrahlen band of SiO2, the hybrid interface polariton assumes surface-phonon-like properties, with a well-defined frequency and momentum and excellent coherence. During the lifetime of the photogenerated electron-hole plasma, coherent hybrid polariton waves can be launched by a broadband mid-infrared pulse coupled to the tip of a scattering-type scanning near-field optical microscopy set-up. The scattered radiation allows us to trace the new hybrid mode in time, energy and space. We find that the surface mode can be activated within ∼50 fs and disappears within 5 ps, as the electron-hole pairs in black phosphorus recombine. The excellent switching contrast and switching speed, the coherence properties and the constant wavelength of this transient mode make it a promising candidate for ultrafast nanophotonic devices.

Excitonic Valley Effects in Monolayer WS2 under High Magnetic Fields.

Transition-metal dichalcogenides can be easily produced as atomically thin sheets, exhibiting the possibility to optically polarize and read out the valley pseudospin of extremely stable excitonic quasiparticles present in these 2D semiconductors. Here, we investigate a monolayer of tungsten disulfide in high magnetic fields up to 30 T via photoluminescence spectroscopy at low temperatures. The valley degeneracy is lifted for all optical features, particularly for excitons, singlet and triplet trions, for which we determine the g factor separately. While the observation of a diamagnetic shift of the exciton and trion resonances gives us insight into the real-space extension of these quasiparticles, magnetic field-induced valley polarization effects shed light onto the exciton and trion dispersion relations in reciprocal space. The field dependence of the trion valley polarizations is in line with the predicted trion splitting into singlet and triplet configurations.

Infiltration of circulating myeloid cells through CD95L contributes to neurodegeneration in mice.

Neuroinflammation is increasingly recognized as a hallmark of neurodegeneration. Activated central nervous system-resident microglia and infiltrating immune cells contribute to the degeneration of dopaminergic neurons (DNs). However, how the inflammatory process leads to neuron loss and whether blocking this response would be beneficial to disease progression remains largely unknown. CD95 is a mediator of inflammation that has also been proposed as an apoptosis inducer in DNs, but previous studies using ubiquitous deletion of CD95 or CD95L in mouse models of neurodegeneration have generated conflicting results. Here we examine the role of CD95 in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridin (MPTP)-induced neurodegeneration using tissue-specific deletion of CD95 or CD95L. We show that DN death is not mediated by CD95-induced apoptosis because deletion of CD95 in DNs does not influence MPTP-induced neurodegeneration. In contrast, deletion of CD95L in peripheral myeloid cells significantly protects against MPTP neurotoxicity and preserves striatal dopamine levels. Systemic pharmacological inhibition of CD95L dampens the peripheral innate response, reduces the accumulation of infiltrating myeloid cells, and efficiently prevents MPTP-induced DN death. Altogether, this study emphasizes the role of the peripheral innate immune response in neurodegeneration and identifies CD95 as potential pharmacological target for neurodegenerative disease.

Anle138b: a novel oligomer modulator for disease-modifying therapy of neurodegenerative diseases such as prion and Parkinson's disease.

In neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and prion diseases, deposits of aggregated disease-specific proteins are found. Oligomeric aggregates are presumed to be the key neurotoxic agent. Here we describe the novel oligomer modulator anle138b [3-(1,3-benzodioxol-5-yl)-5-(3-bromophenyl)-1H-pyrazole], an aggregation inhibitor we developed based on a systematic high-throughput screening campaign combined with medicinal chemistry optimization. In vitro, anle138b blocked the formation of pathological aggregates of prion protein (PrP(Sc)) and of α-synuclein (α-syn), which is deposited in PD and other synucleinopathies such as dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). Notably, anle138b strongly inhibited all prion strains tested including BSE-derived and human prions. Anle138b showed structure-dependent binding to pathological aggregates and strongly inhibited formation of pathological oligomers in vitro and in vivo both for prion protein and α-synuclein. Both in mouse models of prion disease and in three different PD mouse models, anle138b strongly inhibited oligomer accumulation, neuronal degeneration, and disease progression in vivo. Anle138b had no detectable toxicity at therapeutic doses and an excellent oral bioavailability and blood-brain-barrier penetration. Our findings indicate that oligomer modulators provide a new approach for disease-modifying therapy in these diseases, for which only symptomatic treatment is available so far. Moreover, our findings suggest that pathological oligomers in neurodegenerative diseases share structural features, although the main protein component is disease-specific, indicating that compounds such as anle138b that modulate oligomer formation by targeting structure-dependent epitopes can have a broad spectrum of activity in the treatment of different protein aggregation diseases.

Inhibition of rho kinase enhances survival of dopaminergic neurons and attenuates axonal loss in a mouse model of Parkinson's disease.

Axonal degeneration is one of the earliest features of Parkinson's disease pathology, which is followed by neuronal death in the substantia nigra and other parts of the brain. Inhibition of axonal degeneration combined with cellular neuroprotection therefore seem key to targeting an early stage in Parkinson's disease progression. Based on our previous studies in traumatic and neurodegenerative disease models, we have identified rho kinase as a molecular target that can be manipulated to disinhibit axonal regeneration and improve survival of lesioned central nervous system neurons. In this study, we examined the neuroprotective potential of pharmacological rho kinase inhibition mediated by fasudil in the in vitro 1-methyl-4-phenylpyridinium cell culture model and in the subchronic in vivo 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson's disease. Application of fasudil resulted in a significant attenuation of dopaminergic cell loss in both paradigms. Furthermore, dopaminergic terminals were preserved as demonstrated by analysis of neurite network in vitro, striatal fibre density and by neurochemical analysis of the levels of dopamine and its metabolites in the striatum. Behavioural tests demonstrated a clear improvement in motor performance after fasudil treatment. The Akt survival pathway was identified as an important molecular mediator for neuroprotective effects of rho kinase inhibition in our paradigm. We conclude that inhibition of rho kinase using the clinically approved small molecule inhibitor fasudil may be a promising new therapeutic strategy for Parkinson's disease.

Pegylated granulocyte colony-stimulating factor conveys long-term neuroprotection and improves functional outcome in a model of Parkinson's disease.

Recent proof-of-principle data showed that the haematopoietic growth factor granulocyte colony-stimulating factor (filgrastim) mediates neuroprotection in rodent models of Parkinson's disease. In preparation for future clinical trials, we performed a preclinical characterization of a pegylated derivative of granulocyte colony-stimulating factor (pegfilgrastim) in the mouse 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of Parkinson's disease. We determined serum and cerebrospinal fluid drug levels after subcutaneous injection. A single injection of pegfilgrastim was shown to achieve stable levels of granulocyte colony-stimulating factor in both serum and cerebrospinal fluid with substantially higher levels compared to repetitive filgrastim injections. Leucocyte blood counts were only transiently increased after repeated injections. We demonstrated substantial dose-dependent long-term neuroprotection by pegfilgrastim in both young and aged mice, using bodyweight-adjusted doses that are applicable in clinical settings. Importantly, we found evidence for the functionally relevant preservation of nigrostriatal projections by pegfilgrastim in our model of Parkinson's disease, which resulted in improved motor performance. The more stable levels of pegylated neuroprotective proteins in serum and cerebrospinal fluid may represent a general advantage in the treatment of chronic neurodegenerative diseases and the resulting longer injection intervals are likely to improve patient compliance. In summary, we found that pegylation of a neuroprotective growth factor improved its pharmacokinetic profile over its non-modified counterpart in an in vivo model of Parkinson's disease. As the clinical safety profile of pegfilgrastim is already established, these data suggest that evaluation of pegfilgrastim in further Parkinson's disease models and ultimately clinical feasibility studies are warranted.

Both systemic and local application of granulocyte-colony stimulating factor (G-CSF) is neuroprotective after retinal ganglion cell axotomy.

BACKGROUND: The hematopoietic Granulocyte-Colony Stimulating Factor (G-CSF) plays a crucial role in controlling the number of neutrophil progenitor cells. Its function is mediated via the G-CSF receptor, which was recently found to be expressed also in the central nervous system. In addition, G-CSF provided neuroprotection in models of neuronal cell death. Here we used the retinal ganglion cell (RGC) axotomy model to compare effects of local and systemic application of neuroprotective molecules. RESULTS: We found that the G-CSF receptor is robustly expressed by RGCs in vivo and in vitro. We thus evaluated G-CSF as a neuroprotectant for RGCs and found a dose-dependent neuroprotective effect of G-CSF on axotomized RGCs when given subcutaneously. As stem stell mobilization had previously been discussed as a possible contributor to the neuroprotective effects of G-CSF, we compared the local treatment of RGCs by injection of G-CSF into the vitreous body with systemic delivery by subcutaneous application. Both routes of application reduced retinal ganglion cell death to a comparable extent. Moreover, G-CSF enhanced the survival of immunopurified RGCs in vitro. CONCLUSION: We thus show that G-CSF neuroprotection is at least partially independent of potential systemic effects and provide further evidence that the clinically applicable G-CSF could become a treatment option for both neurodegenerative diseases and glaucoma.