To VBAC or Not to VBAC

Catherine Spong discusses new research in PLoS Medicine that sheds more light on the risks of uterine rupture for women attempting a trial of labor following previous cesarean section

Dorsal hippocampal involvement in conditioned-response timing and maintenance of temporal information in the absence of the CS

Involvement of the dorsal hippocampus (DHPC) in conditioned-response timing and maintaining temporal information across time gaps was examined in an appetitive Pavlovian conditioning task, in which rats with sham and DHPC lesions were first conditioned to a 15-s visual cue. After acquisition, the subjects received a series of non-reinforced test trials, on which the visual cue was extended (45 s) and gaps of different duration, 0.5, 2.5, and 7.5 s, interrupted the early portion of the cue. Dorsal hippocampal-lesioned subjects underestimated the target duration of 15 s and showed broader response distributions than the control subjects on the no-gap trials in the first few blocks of test, but the accuracy and precision of their timing reached the level of that of the control subjects by the last block. On the gap trials, the DHPC-lesioned subjects showed greater rightward shifts in response distributions than the control subjects. We discussed these lesion effects in terms of temporal versus non-temporal processing (response inhibition, generalisation decrement, and inhibitory conditioning)

On the selection and design of proteins and peptide derivatives for the production of photoluminescent, red-emitting gold quantum clusters

Novel pathways of the synthesis of photoluminescent gold quantum clusters (AuQCs) using biomolecules as reactants provide biocompatible products for biological imaging techniques. In order to rationalize the rules for the preparation of red-emitting AuQCs in aqueous phase using proteins or peptides, the role of different organic structural units was investigated. Three systems were studied: proteins, peptides, and amino acid mixtures, respectively. We have found that cysteine and tyrosine are indispensable residues. The SH/S-S ratio in a single molecule is not a critical factor in the synthesis, but on the other hand, the stoichiometry of cysteine residues and the gold precursor is crucial. These observations indicate the importance of proper chemical behavior of all species in a wide size range extending from the atomic distances (in the AuI-S semi ring) to nanometer distances covering the larger sizes of proteins assuring the hierarchical structure of the whole self-assembled system

Nanoscale atomic waveguides with suspended carbon nanotubes

We propose an experimentally viable setup for the realization of one-dimensional ultracold atom gases in a nanoscale magnetic waveguide formed by single doubly-clamped suspended carbon nanotubes. We show that all common decoherence and atom loss mechanisms are small guaranteeing a stable operation of the trap. Since the extremely large current densities in carbon nanotubes are spatially homogeneous, our proposed architecture allows to overcome the problem of fragmentation of the atom cloud. Adding a second nanowire allows to create a double-well potential with a moderate tunneling barrier which is desired for tunneling and interference experiments with the advantage of tunneling distances being in the nanometer regime.Comment: Replaced with the published version, 7 pages, 3 figure

Hibernation-like state induced by an opioid peptide protects against experimental stroke

BACKGROUND: Delta opioid peptide [D-ala2,D-leU5]enkephalin (DADLE) induces hibernation in summer ground squirrels, and enhances preservation and survival of isolated or transplanted lungs and hearts. In the present study, we investigated the protective effect of DADLE in the central nervous system. RESULTS: Adult Sprague-Dawley rats were pretreated with DADLE (4 mg/kg every 2 h x 4 injections, i.p.) or saline prior to unilateral occlusion of the middle cerebral artery (MCA). Daily behavioral tests revealed that ischemic animals treated with DADLE did not show any significant behavioral dysfunctions compared with saline-treated ischemic animals. Opioid antagonists only transiently inhibited the protective effect of DADLE, indicating the participation of non-opioid mechanisms in DADLE neuroprotection. Histological examination using triphenyltetrazolium chloride (TTC) revealed that brains from ischemic animals treated with DADLE, either alone or with adjuvant opioid blockers, exhibited almost completely intact striata. In contrast, brains from ischemic animals that received saline showed significant infarction in the lateral striatum. Analyses of apoptotic cell death revealed a significant increase in the p-53 mRNA expression in the striatum of ischemic animals that received saline, while those that received DADLE exhibited near normal striatal p-53 expression. This protective effect was accompanied by significant increments in protein levels of glial cell line-derived neurotrophic factor in the striatum of DADLE-treated ischemic animals. CONCLUSION: These results indicate that DADLE protected against necrotic and apoptotic cell death processes associated with ischemia-reperfusion injury. The present study demonstrates that delta opioids are crucially involved in stroke, suggesting that the opioid system is important in the study of brain injury and protection

Observation of Bose-Einstein Condensation in a Strong Synthetic Magnetic Field

Extensions of Berry's phase and the quantum Hall effect have led to the discovery of new states of matter with topological properties. Traditionally, this has been achieved using gauge fields created by magnetic fields or spin orbit interactions which couple only to charged particles. For neutral ultracold atoms, synthetic magnetic fields have been created which are strong enough to realize the Harper-Hofstadter model. Despite many proposals and major experimental efforts, so far it has not been possible to prepare the ground state of this system. Here we report the observation of Bose-Einstein condensation for the Harper-Hofstadter Hamiltonian with one-half flux quantum per lattice unit cell. The diffraction pattern of the superfluid state directly shows the momentum distribution on the wavefuction, which is gauge-dependent. It reveals both the reduced symmetry of the vector potential and the twofold degeneracy of the ground state. We explore an adiabatic many-body state preparation protocol via the Mott insulating phase and observe the superfluid ground state in a three-dimensional lattice with strong interactions.Comment: 6 pages, 5 figures. Supplement: 6 pages, 4 figure

Interferon-γ Activates Nuclear Factor-κ B in Oligodendrocytes through a Process Mediated by the Unfolded Protein Response

Our previous studies have demonstrated that the effects of the immune cytokine interferon-γ (IFN-γ) in immune-mediated demyelinating diseases are mediated, at least in part, by the unfolded protein response (UPR) in oligodendrocytes. Data indicate that some biological effects of IFN-γ are elicited through activation of the transcription factor nuclear factor-κB (NF-κB). Interestingly, it has been shown that activation of the pancreatic endoplasmic reticulum kinase (PERK) branch of the UPR triggers NF-κB activation. In this study, we showed that IFN-γ-induced NF-κB activation was associated with activation of PERK signaling in the oligodendroglial cell line Oli-neu. We further demonstrated that blockage of PERK signaling diminished IFN-γ-induced NF-κB activation in Oli-neu cells. Importantly, we showed that NF-κB activation in oligodendrocytes correlated with activation of PERK signaling in transgenic mice that ectopically express IFN-γ in the central nervous system (CNS), and that enhancing IFN-γ-induced activation of PERK signaling further increased NF-κB activation in oligodendrocytes. Additionally, we showed that suppression of the NF-κB pathway rendered Oli-neu cells susceptible to the cytotoxicity of IFN-γ, reactive oxygen species, and reactive nitrogen species. Our results indicate that the UPR is involved in IFN-γ-induced NF-κB activation in oligodendrocytes and suggest that NF-κB activation by IFN-γ represents one mechanism by which IFN-γ exerts its effects on oligodendrocytes in immune-mediated demyelinating diseases

Catheter manipulation analysis for objective performance and technical skills assessment in transcatheter aortic valve implantation

Purpose Transcatheter aortic valve implantation (TAVI) demands precise and efficient handling of surgical instruments within the confines of the aortic anatomy. Operational performance and dexterous skills are critical for patient safety, and objective methods are assessed with a number of manipulation features, derived from the kinematic analysis of the catheter/guidewire in fluoroscopy video sequences. Methods A silicon phantom model of a type I aortic arch was used for this study. Twelve endovascular surgeons, divided into two experience groups, experts (n=6) and novices (n=6), performed cannulation of the aorta, representative of valve placement in TAVI. Each participant completed two TAVI experiments, one with conventional catheters and one with the Magellan robotic platform. Video sequences of the fluoroscopic monitor were recorded for procedural processing. A semi-automated tracking software provided the 2D coordinates of the catheter/guidewire tip. In addition, the aorta phantom was segmented in the videos and the shape of the entire catheter was manually annotated in a subset of the available video frames using crowdsourcing. The TAVI procedure was divided into two stages, and various metrics, representative of the catheter’s overall navigation as well as its relative movement to the vessel wall, were developed. Results Experts consistently exhibited lower values of procedure time and dimensionless jerk, and higher average speed and acceleration than novices. Robotic navigation resulted in increased average distance to the vessel wall in both groups, a surrogate measure of safety and reduced risk of embolisation. Discrimination of experience level and types of equipment was achieved with the generated motion features and established clustering algorithms. Conclusions Evaluation of surgical skills is possible through the analysis of the catheter/guidewire motion pattern. The use of robotic endovascular platforms seems to enable more precise and controlled catheter navigation

Nuclear localization and function of polypeptide ligands and their receptors: a new paradigm for hormone specificity within the mammary gland?

The specific effects triggered by polypeptide hormone/growth factor stimulation of mammary cells were considered mediated solely by receptor-associated signaling networks. A compelling body of new data, however, clearly indicates that polypeptide ligands and/or their receptors are transported into the nucleus, where they function directly to regulate the expression of specific transcription factors and gene loci. The intranuclear function of these complexes may contribute to the explicit functions associated with a given ligand, and may serve as new targets for pharmacologic intervention