Plasticity of Expression of a Synaptic Vesicle Antigen in Adult Rat Superior Cervical Ganglion

The effects of deafferentation and alterations of synaptic activity on levels of a synaptic vesicle-specific membrane protein (SV) were studied in the adult rat superior cervical ganglion (SCG) in vivo, using a monoclonal antibody directed against the protein. Levels of SV were quantified by radioimmunoassay. Deafferentation of the SCG results in a transient increase in SV levels in the SCG on days 7 and 10 after surgery, with levels then dropping below control levels on days 14, 21, and 30 after surgery. Immunohistochemical labeling of deafferented ganglia indicates that the increase is confined to the perikarya of principal ganglionic neurons. Levels of SV in an SCG target tissue, the iris, do not differ from control levels on day 7 after deafferentation, but are elevated at days 10, 14, and 30 after surgery. After reinnervation of the SCG, levels of SV in the SCG are elevated above control values, but do not differ from control values in the iris. Treatment with chlorisondamine, which blocks synaptic transmission in sympathetic ganglia, produces a significant increase in SV levels in the SCG after 7 d of treatment. Long-term chlorisondamine treatment results in reductions in SV in the SCG after 14 and 28 d. Treatment with phenoxybenzamine for 6 d, which reflexly increases synaptic activity, produces a marked decrease in SV in the SCG. These results suggest that activity, mediated by transsynaptic factors, contributes to the regulation of synthesis of a synaptic vesicle protein in the SCG. The results further suggest that accumulation of synaptic vesicles in terminals of the principal ganglion neurons may help regulate the maintenance of normal synaptic vesicle pools within sympathetic neurons

Plasticity of Expression of a Synaptic Vesicle Antigen in Adult Rat Superior Cervical Ganglion

The effects of deafferentation and alterations of synaptic activity on levels of a synaptic vesicle-specific membrane protein (SV) were studied in the adult rat superior cervical ganglion (SCG) in vivo, using a monoclonal antibody directed against the protein. Levels of SV were quantified by radioimmunoassay. Deafferentation of the SCG results in a transient increase in SV levels in the SCG on days 7 and 10 after surgery, with levels then dropping below control levels on days 14, 21, and 30 after surgery. Immunohistochemical labeling of deafferented ganglia indicates that the increase is confined to the perikarya of principal ganglionic neurons. Levels of SV in an SCG target tissue, the iris, do not differ from control levels on day 7 after deafferentation, but are elevated at days 10, 14, and 30 after surgery. After reinnervation of the SCG, levels of SV in the SCG are elevated above control values, but do not differ from control values in the iris. Treatment with chlorisondamine, which blocks synaptic transmission in sympathetic ganglia, produces a significant increase in SV levels in the SCG after 7 d of treatment. Long-term chlorisondamine treatment results in reductions in SV in the SCG after 14 and 28 d. Treatment with phenoxybenzamine for 6 d, which reflexly increases synaptic activity, produces a marked decrease in SV in the SCG. These results suggest that activity, mediated by transsynaptic factors, contributes to the regulation of synthesis of a synaptic vesicle protein in the SCG. The results further suggest that accumulation of synaptic vesicles in terminals of the principal ganglion neurons may help regulate the maintenance of normal synaptic vesicle pools within sympathetic neurons

Angle-resolved photoemission spectroscopy with quantum gas microscopes

Quantum gas microscopes are a promising tool to study interacting quantum many-body systems and bridge the gap between theoretical models and real materials. So far they were limited to measurements of instantaneous correlation functions of the form $\langle \hat{O}(t) \rangle$, even though extensions to frequency-resolved response functions $\langle \hat{O}(t) \hat{O}(0) \rangle$ would provide important information about the elementary excitations in a many-body system. For example, single particle spectral functions, which are usually measured using photoemission experiments in electron systems, contain direct information about fractionalization and the quasiparticle excitation spectrum. Here, we propose a measurement scheme to experimentally access the momentum and energy resolved spectral function in a quantum gas microscope with currently available techniques. As an example for possible applications, we numerically calculate the spectrum of a single hole excitation in one-dimensional $t-J$ models with isotropic and anisotropic antiferromagnetic couplings. A sharp asymmetry in the distribution of spectral weight appears when a hole is created in an isotropic Heisenberg spin chain. This effect slowly vanishes for anisotropic spin interactions and disappears completely in the case of pure Ising interactions. The asymmetry strongly depends on the total magnetization of the spin chain, which can be tuned in experiments with quantum gas microscopes. An intuitive picture for the observed behavior is provided by a slave-fermion mean field theory. The key properties of the spectra are visible at currently accessible temperatures.Comment: 16+7 pages, 10+2 figure

Site-resolved imaging of a fermionic Mott insulator

The complexity of quantum many-body systems originates from the interplay of strong interactions, quantum statistics, and the large number of quantum-mechanical degrees of freedom. Probing these systems on a microscopic level with single-site resolution offers important insights. Here we report site-resolved imaging of two-component fermionic Mott insulators, metals, and band insulators using ultracold atoms in a square lattice. For strong repulsive interactions we observe two-dimensional Mott insulators containing over 400 atoms. For intermediate interactions, we observe a coexistence of phases. From comparison to theory we find trap-averaged entropies per particle of $1.0\,k_{\mathrm{B}}$. In the band-insulator we find local entropies as low as $0.5\,k_{\mathrm{B}}$. Access to local observables will aid the understanding of fermionic many-body systems in regimes inaccessible by modern theoretical methods.Comment: 6+7 page

Dislocations and melting in two dimensions: The critical region

A new analysis is presented of the critical-point behavior of two-dimensional melting in the Kosterlitz-Thouless-Nelson-Halperin-Young theory. The analysis confirms the Kosterlitz-Thouless-Nelson-Halperin-Young critical-point exponent, ν̅=0.36963…, but also gives a criterion for its own range of validity amounting to t>10^13 lattice spacings. The implications of these results for experimental verification are discussed

Ultrasound-guided spermatic cord block for scrotal surgery

Background Performing spermatic cord block for scrotal surgery avoids the potential risks of neuraxial and general anaesthesia and provides long-lasting postoperative analgesia. A blindly performed block is often inefficient and bears its own potential risks (intravascular injection of local anaesthetics, haematoma formation and perforation of the deferent duct). The use of ultrasound may help to overcome these disadvantages. The aim of this study was to test the feasibility and monitor the success rate of a new ultrasound-guided spermatic cord block. Methods Twenty consecutive patients undergoing urologic surgery (subcapsular orchiectomy or vaso-vasostomy) were included in this prospective study. Using a linear ultrasound probe, the spermatic cord was identified by locating the spermatic artery and the deferent duct. A 23 G Microlance needle was advanced close to the deferent duct by avoiding vessel perforation, and local anaesthetic was deposited around the deferent duct under direct visualization. The primary outcome was the success rate of the block which was defined as surgery without any substitution of opioids, additional local anaesthetics, or sedatives. Results In 20 patients, 40 blocks were performed with a success rate of 95% (n=38). The failure rate was 5% (n=2) and no conversion to general anaesthesia was needed. The mean duration of the block was 14.1 h (sd 6.9). Conclusions The use of ultrasound guidance to perform spermatic cord block is feasible and has a high success rate. Our new approach may become a suitable alternative to neuraxial or general anaesthesia especially in the ambulatory surgical setting. Registry: International Standard Randomised Controlled Trial Number Register; www.controlled-trials.com; Registry Nr.: ISRCTN4464781

Recent Decisions

Comments on recent decisions by John M. Sullivan, William G. Greif, Joseph F. MacKrell, William N. Antonis, Thomas Meaney, Jr., William J. Hurley, Joseph H. Harrison, Robert L. Berry, Robert F. McCoy, Edward Canary, Maynard R. Bissonnette, and Luke R. Morin

Recent Decisions

Comments on recent decisions by John F. Mendoza, William J. Verdonk, William G. Greif, James L. O\u27Brien, F. Richard Kramer, Louis Albert Hafner, Peter F. Flaherty, Wilmer L. McLaughlin, Louis F. DiGiovanni, Vincent C. A. Scully, Bernard L. Weddel, and William B. Wombacher