Imaging the Meissner effect in hydride superconductors using quantum sensors.

By directly altering microscopic interactions, pressure provides a powerful tuning knob for the exploration of condensed phases and geophysical phenomena1. The megabar regime represents an interesting frontier, in which recent discoveries include high-temperature superconductors, as well as structural and valence phase transitions2-6. However, at such high pressures, many conventional measurement techniques fail. Here we demonstrate the ability to perform local magnetometry inside a diamond anvil cell with sub-micron spatial resolution at megabar pressures. Our approach uses a shallow layer of nitrogen-vacancy colour centres implanted directly within the anvil7-9; crucially, we choose a crystal cut compatible with the intrinsic symmetries of the nitrogen-vacancy centre to enable functionality at megabar pressures. We apply our technique to characterize a recently discovered hydride superconductor, CeH9 (ref. 10). By performing simultaneous magnetometry and electrical transport measurements, we observe the dual signatures of superconductivity: diamagnetism characteristic of the Meissner effect and a sharp drop of the resistance to near zero. By locally mapping both the diamagnetic response and flux trapping, we directly image the geometry of superconducting regions, showing marked inhomogeneities at the micron scale. Our work brings quantum sensing to the megabar frontier and enables the closed-loop optimization of superhydride materials synthesis.

A systematic review of the impact of postoperative aerobic exercise training in patients undergoing surgery for intra-abdominal cancers.

INTRODUCTION: Enhanced recovery after surgery (ERAS) programmes which advocate early mobility after surgery have improved immediate clinical outcomes for patients undergoing abdominal cancer resections with curative intent. However, the impact of continued physical activity on patient-related outcomes and functional recovery is not well defined. The aim of this review was to assess the impact of postoperative aerobic exercise training, either alone or in conjunction with another exercise modality, on patients who have had surgery for intra-abdominal cancer. METHODS: A literature search was performed of electronic journal databases. Eligible papers needed to report an outcome of aerobic capacity in patients older than 18 years of age, who underwent cancer surgery with curative intent and participated in an exercise programme (not solely ERAS) that included an aerobic exercise component starting at any point in the postoperative pathway up to 12 weeks. RESULTS: Eleven studies were deemed eligible for inclusion consisting of two inpatient, one mixed inpatient/outpatient and eight outpatient studies. Meta-analysis of four outpatient studies, each reporting change in 6-min walk test (6MWT), showed a significant improvement in 6MWT with exercise (MD 74.92 m, 95% CI 48.52-101.31 m). The impact on health-related quality of life was variable across studies. CONCLUSION: Postoperative exercise confers benefits in improving aerobic function post surgery and can be safely delivered in various formats (home-based or group/supervised).

[Serotonin receptor 1A-modulated dephosphorylation of glycine receptor α3: a new molecular mechanism of breathing control for compensation of opioid-induced respiratory depression without loss of analgesia]. / Die von Serotoninrezeptor 1A modulierte Dephosphorylierung des Glyzinrezeptors α3: Ein neuer molekularer Mechanismus der Atmungskontrolle zur Kompensation opioidinduzierter Atemdepression ohne Verlust der Analgesie.

To control the breathing rhythm the medullary respiratory network generates periodic salvo activities for inspiration, post-inspiration and expiration. These are under permanent modulatory control by serotonergic neurons of the raphe which governs the degree of phosphorylation of the inhibitory glycine receptor α3. The specific activation of serotonin receptor type 1A (5-HTR(1A)), which is strongly expressed in the respiratory neurons, functions via inhibition of adenylate cyclase and the resulting reduction of the intracellular cAMP level and a gradual dephosphorylation of the glycine receptor type α3 (GlyRα3). This 5-HTR(1A)-GlyRα3 signal pathway is independent of the µ-opioidergic transduction pathway and via a synaptic inhibition caused by an increase in GlyRα3 stimulates a disinhibition of some target neurons not only from excitatory but also from inhibitory neurons. Our physiological investigations show that this 5-HTR(1A)-GlyRα3 modulation allows treatment of respiratory depression due to opioids without affecting the desired analgesic effects of opioids. The molecular mechanism presented here opens new pharmacological possibilities to treat opioid-induced respiratory depression and respiratory disorders due to disturbed inhibitory synaptic transmission, such as hyperekplexia.

Women with hypoactive sexual desire disorder compared to normal females: a functional magnetic resonance imaging study.

Lack of sexual interest is the most common sexual complaint among women. However, factors affecting sexual desire in women have rarely been studied. While the role of the brain in integrating the sensory, attentional, motivational, and motor aspects of sexual response is commonly acknowledged as important, little is known about specific patterns of brain activation and sexual interest or response, particularly among women. We compared 20 females with no history of sexual dysfunction (NHSD) to 16 women with hypoactive sexual desire disorder (HSDD) in a functional magnetic resonance imaging (fMRI) study that included assessment of subjective sexual arousal, peripheral sexual response using a vaginal photoplethysmograph (VPP), as well as brain activation across three time points. Video stimuli included erotic, sports, and relaxing segments. Subjective arousal to erotic stimuli was significantly greater in NHSD participants compared with HSDD. In the erotic-sports contrast, NHSD women showed significantly greater activation in the bilateral entorhinal cortex than HSDD women. In the same contrast, HSDD females demonstrated higher activation than NHSD females in the medial frontal gyrus (Brodmann area (BA) 10), right inferior frontal gyrus (BA 47) and bilateral putamen. There were no between group differences in VPP-correlated brain activation and peripheral sexual response was not significantly associated with either subjective sexual response or brain activation patterns. Findings were consistent across the three experimental sessions. The results suggest differences between women with NHSD and HSDD in encoding arousing stimuli, retrieval of past erotic experiences, or both. The findings of greater activation in BA 10 and BA 47 among women with HSDD suggest that this group allocated significantly more attention to monitoring and/or evaluating their responses than NHSD participants, which may interfere with normal sexual response.

Behavioral effects in monkeys of racemates of two biologically active marijuana constituents.

Both dl-Delta(8)- and dl-Delta(9)-tetrahydrocannabinol produced marked alterations of behavior in rhesus and squirrel monkeys. Squirrel monkeys appeared to have visual hallucinations. Continuous avoidance behavior of squirrel monkeys was stimulated by both drugs, but high doses of dl-Delta(9)-tetrahydrocannabinol also caused depression after the stimulant phase. Complex behavior involving memory and visual discrimination in rhesus monkeys was markedly disrupted by both drugs.

Functional modulation of GABAA receptors by cAMP-dependent protein phosphorylation.

gamma-Aminobutyric acidA (GABAA) receptors are ligand-gated ion channels that mediate inhibitory synaptic transmission in the central nervous system. The role of protein phosphorylation in the modulation of GABAA receptor function was examined with cells transiently transfected with GABAA receptor subunits. GABAA receptors consisting of the alpha 1 and beta 1 or the alpha 1, beta 1, and gamma 2 subunits were directly phosphorylated on the beta 1 subunit by adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase (PKA). The phosphorylation decreased the amplitude of the GABA response of both receptor types and the extent of rapid desensitization of the GABAA receptor that consisted of the alpha 1 and beta 1 subunits. Site-specific mutagenesis of the serine residue phosphorylated by PKA completely eliminated the PKA phosphorylation and modulation of the GABAA receptor. In primary embryonic rat neuronal cell cultures, a similar regulation of GABAA receptors by PKA was observed. These results demonstrate that the GABAA receptor is directly modulated by protein phosphorylation and suggest that neurotransmitters or neuropeptides that regulate intracellular cAMP levels may modulate the responses of neurons to GABA and consequently have profound effects on synaptic excitability.

Imaging stress and magnetism at high pressures using a nanoscale quantum sensor.

Pressure alters the physical, chemical, and electronic properties of matter. The diamond anvil cell enables tabletop experiments to investigate a diverse landscape of high-pressure phenomena. Here, we introduce and use a nanoscale sensing platform that integrates nitrogen-vacancy (NV) color centers directly into the culet of diamond anvils. We demonstrate the versatility of this platform by performing diffraction-limited imaging of both stress fields and magnetism as a function of pressure and temperature. We quantify all normal and shear stress components and demonstrate vector magnetic field imaging, enabling measurement of the pressure-driven [Formula: see text] phase transition in iron and the complex pressure-temperature phase diagram of gadolinium. A complementary NV-sensing modality using noise spectroscopy enables the characterization of phase transitions even in the absence of static magnetic signatures.

Regulation of GABAA receptor function by protein kinase C phosphorylation.

GABAA receptors possess consensus sequences for phosphorylation by PKC that are located on the presumed intracellular domains of beta and gamma 2 subunits. PKC phosphorylation sites were analyzed using purified receptor subunits and were located on up to 3 serine residues in beta 1 and gamma 2 subunits. The role of phosphorylation in receptor function was studied using recombinant receptors expressed in kidney cells and Xenopus oocytes and was compared with native neuronal GABAA receptors. For recombinant and native GABAA receptors, PKC phosphorylation caused a reduction in the amplitudes of GABA-activated currents without affecting the time constants for current decay. Selective site-directed mutagenesis of the serine residues reduced the effects of phorbol esters and revealed that serine 343 in the gamma 2 subunit exerted the largest effect on the GABA-activated response. These results indicate that PKC phosphorylation can differentially modulate GABAA receptor function.

Adjacent phosphorylation sites on GABAA receptor beta subunits determine regulation by cAMP-dependent protein kinase.

Activation of cAMP-dependent protein kinase (PKA) can enhance or reduce the function of neuronal GABAA receptors, the major sites of fast synaptic inhibition in the brain. This differential regulation depends on PKA-induced phosphorylation of adjacent conserved sites in the receptor beta subunits. Phosphorylation of beta 3 subunit-containing receptors at S408 and S409 enhanced the GABA-activated response, whereas selectively mutating S408 to alanine converted the potentiation into an inhibition, comparable to that of beta 1 subunits, which are phosphorylated solely on S409. These distinct modes of regulation were interconvertible between beta 1 and beta 3 subunits and depended upon the presence of S408 in either subunit. In contrast, beta 2 subunit-containing receptors were not phosphorylated or affected by PKA. Differential regulation by PKA of postsynaptic GABAA receptors containing different beta subunits may have profound effects on neuronal excitability.

Cyclic AMP-dependent protein kinase phosphorylation facilitates GABA(B) receptor-effector coupling.

GABA (gamma-aminobutyric acid)(B) receptors are heterodimeric G protein-coupled receptors that mediate slow synaptic inhibition in the central nervous system. Here we show that the functional coupling of GABA(B)R1/GABA(B)R2 receptors to inwardly rectifying K(+) channels rapidly desensitizes. This effect is alleviated after direct phosphorylation of a single serine residue (Ser892) in the cytoplasmic tail of GABA(B)R2 by cyclic AMP (cAMP)-dependent protein kinase (PKA). Basal phosphorylation of this residue is evident in rat brain membranes and in cultured neurons. Phosphorylation of Ser892 is modulated positively by pathways that elevate cAMP concentration, such as those involving forskolin and beta-adrenergic receptors. GABA(B) receptor agonists reduce receptor phosphorylation, which is consistent with PKA functioning in the control of GABA(B)-activated currents. Mechanistically, phosphorylation of Ser892 specifically enhances the membrane stability of GABA(B) receptors. We conclude that signaling pathways that activate PKA may have profound effects on GABA(B) receptor-mediated synaptic inhibition. These results also challenge the accepted view that phosphorylation is a universal negative modulator of G protein-coupled receptors.

GABA(A) receptor cell surface number and subunit stability are regulated by the ubiquitin-like protein Plic-1.

Controlling the number of functional gamma-aminobutyric acid A (GABA(A)) receptors in neuronal membranes is a crucial factor for the efficacy of inhibitory neurotransmission. Here we describe the direct interaction of GABA(A) receptors with the ubiquitin-like protein Plic-1. Furthermore, Plic-1 is enriched at inhibitory synapses and is associated with subsynaptic membranes. Functionally, Plic-1 facilitates GABA(A) receptor cell surface expression without affecting the rate of receptor internalization. Plic-1 also enhances the stability of intracellular GABA(A) receptor subunits, increasing the number of receptors available for insertion into the plasma membrane. Our study identifies a previously unknown role for Plic-1, a modulation of GABA(A) receptor cell surface number, which suggests that Plic-1 facilitates accumulation of these receptors in dendritic membranes.

Optical trapping and optical force positioning of two-dimensional materials.

In recent years, considerable effort has been devoted to the synthesis and characterization of two-dimensional materials. Liquid phase exfoliation (LPE) represents a simple, large-scale method to exfoliate layered materials down to mono- and few-layer flakes. In this context, the contactless trapping, characterization, and manipulation of individual nanosheets hold perspectives for increased accuracy in flake metrology and the assembly of novel functional materials. Here, we use optical forces for high-resolution structural characterization and precise mechanical positioning of nanosheets of hexagonal boron nitride, molybdenum disulfide, and tungsten disulfide obtained by LPE. Weakly optically absorbing nanosheets of boron nitride are trapped in optical tweezers. The analysis of the thermal fluctuations allows a direct measurement of optical forces and the mean flake size in a liquid environment. Measured optical trapping constants are compared with T-matrix light scattering calculations to show a quadratic size scaling for small size, as expected for a bidimensional system. In contrast, strongly absorbing nanosheets of molybdenum disulfide and tungsten disulfide are not stably trapped due to the dominance of radiation pressure over the optical trapping force. Thus, optical forces are used to pattern a substrate by selectively depositing nanosheets in short times (minutes) and without any preparation of the surface. This study will be useful for improving ink-jet printing and for a better engineering of optoelectronic devices based on two-dimensional materials.

sn-1,2-diacylglycerol and choline increase after fertilization in Xenopus laevis.

sn-1,2-Diacylglycerol (DAG) mass and translocation of protein kinase C alpha and beta to a membrane fraction increased approximately 7 min after insemination of Xenopus laevis eggs. The DAG mass increase of 48 pmol (from 62 to 110 pmol/cell) was greater than that for inositol 1,4,5-trisphosphate (IP3; an increase of approximately 170 fmol or approximately 280-fold smaller than the DAG increase), and DAG peaks approximately 5 min after IP3. Choline mass (a measure of phosphatidyl choline-specific phospholipase D) also peaked before DAG and the choline increase (134 pmol/cell) was greater than that of DAG. There was no detectable change in phosphocholine mass (a measure of phosphatidylcholine-specific phospholipase C). During first cleavage, DAG decreased, PKC translocation was low, and choline increased and peaked (whereas published work shows an increase in IP3 mass). Artificial elevation of intracellular calcium ([Ca2+]i) increased DAG levels but prevention of the [Ca2+]i increase after fertilization did not block DAG production. Thus, sperm stimulate production of DAG and choline through [Ca2+]i-independent and [Ca2+]i-dependent paths.

Regulation of excitatory and inhibitory neurotransmitter-gated ion channels by protein phosphorylation.

Phosphorylation of ligand-gated ion channels is recognised as a potentially important mechanism for short- and long-term modulation of ion-channel function. Following the discovery of numerous sites of phosphorylation on ligand-gated ion channel proteins, recent studies have demonstrated that neurotransmitter-induced activation of serine/threonine, tyrosine and other kinases can result in the modulation of glutamate, type A gamma-aminobutyric acid (GABAA) and glycine receptors. These findings may have important consequences for our understanding of synaptic transmission and neuronal excitability.

GABA and glycine as neurotransmitters: a brief history.

gamma-Aminobutyric acid (GABA) emerged as a potentially important brain chemical just over 50 years ago, but its significance as a neurotransmitter was not fully realized until over 16 years later. We now know that at least 40% of inhibitory synaptic processing in the mammalian brain uses GABA. Establishing its role as a transmitter was a lengthy process and it seems hard to believe with our current knowledge that there was ever any dispute about its role in the mammalian brain. The detailed information that we now have about the receptors for GABA together with the wealth of agents which facilitate or reduce GABA receptor mechanisms make the prospects for further research very exciting. The emergence of glycine as a transmitter seems relatively painless by comparison to GABA. Perhaps this is appropriate for the simplest of transmitter structures! Its discovery within the spinal cord and brainstem approximately 40 years ago was followed only 2 years later by the proposal that it be conferred with 'neurotransmitter' status. It was another 16 years before the receptor was biochemically isolated. Now it is readily accepted as a vital spinal and supraspinal inhibitory transmitter and we know many details regarding its molecular structure and trafficking around neurones. The pharmacology of these receptors has lagged behind that of GABA. There is not the rich variety of allosteric modulators that we have come to readily associate with GABA receptors and which has provided us with a virtual treasure trove of important drugs used in anxiety, insomnia, epilepsy, anaesthesia, and spasticity, all stemming from the actions of the simple neutral amino acid GABA. Nevertheless, the realization that glycine receptors are involved in motor reflexes and nociceptive pathways together with the more recent advent of drugs that exhibit some subtype selectivity make the goal of designing selective therapeutic ligands for the glycine receptor that much closer.

Constitutive endocytosis of GABAA receptors by an association with the adaptin AP2 complex modulates inhibitory synaptic currents in hippocampal neurons.

Type A GABA receptors (GABA(A)) mediate the majority of fast synaptic inhibition in the brain and are believed to be predominantly composed of alpha, beta, and gamma subunits. Although changes in cell surface GABA(A) receptor number have been postulated to be of importance in modulating inhibitory synaptic transmission, little is currently known on the mechanism used by neurons to modify surface receptor levels at inhibitory synapses. To address this issue, we have studied the cell surface expression and maintenance of GABA(A) receptors. Here we show that constitutive internalization of GABA(A) receptors in hippocampal neurons and recombinant receptors expressed in A293 cells is mediated by clathrin-dependent endocytosis. Furthermore, we identify an interaction between the GABA(A) receptor beta and gamma subunits with the adaptin complex AP2, which is critical for the recruitment of integral membrane proteins into clathrin-coated pits. GABA(A) receptors also colocalize with AP2 in cultured hippocampal neurons. Finally, blocking clathrin-dependant endocytosis with a peptide that disrupts the association between amphiphysin and dynamin causes a large sustained increase in the amplitude of miniature IPSCs in cultured hippocampal neurons. These results suggest that GABA(A) receptors cycle between the synaptic membrane and intracellular sites, and their association with AP2 followed by recruitment into clathrin-coated pits represents an important mechanism in the postsynaptic modulation of inhibitory synaptic transmission.

Results of a phase II study using estramustine phosphate and vinblastine in combination with high-dose three-dimensional conformal radiotherapy for patients with locally advanced prostate cancer.

PURPOSE: To assess the feasibility and tolerance of neoadjuvant and concomitant estramustine phosphate and vinblastine (EV) with high-dose three-dimensional conformal radiotherapy (3D-CRT) for patients with unfavorable-risk prostate cancer. PATIENTS AND METHODS: Twenty-seven patients with unfavorable-risk prostate cancer were enrolled onto a prospective study to determine the feasibility of combining EV with 3D-CRT. Patients were eligible if any of the following requirements were satisfied: (1) Gleason score > or =8 and prostate-specific antigen (PSA) > 10 ng/mL; (2) Gleason score of 7 and PSA > 20 ng/mL; (3) clinical stage T3N0M0 disease with PSA > 20 ng/mL; (4) any patient with T4N0M0 disease; or (5) patients with TXN1MO disease. Therapy consisted of three 8-week cycles of EV and 8 weeks of 3D-CRT. Estramustine phosphate was given orally beginning on week 1 and continued until the completion of 3D-CRT. Each 8-week cycle of vinblastine consisted of 6 weekly intravenous injections followed by a 2-week rest period. Radiation therapy was administered using a three-dimensional conformal approach to a prescription dose of 75.6 Gy. The median follow-up was 26 months (range, 6 to 40 months). RESULTS: Twenty-three (85%) of 27 patients completed the entire course of therapy and were assessable for toxicities and biochemical outcome. Two patients (7%) developed grade 3 hematologic toxicity that resolved, and two patients (7%) developed grade 3 hepatoxicity, manifesting as persistent elevation of serum transaminase levels, necessitating discontinuation of the chemotherapy and withdrawal from the treatment program. The most prominent adverse effects from this regimen were mild to moderate (grade 1 to 2) nausea and fatigue related to estramustine. Mild peripheral edema was seen in 15% of patients and was treated with diuresis. 3D-CRT was tolerated well in these patients. Medications were required for relief of acute grade 2 rectal (gastrointestinal [GI]) and urinary (genitourinary [GU]) symptoms in 35% and 48% of patients, respectively. Three patients developed acute grade 3 GU toxicities. The 2-year actuarial likelihood of late grade 2 GI toxicity was 20%. No late grade 3 or 4 GI toxicities were observed. The 2-year actuarial likelihoods of late grade 2 and 3 GU toxicities were 25% and 12%, respectively. No grade 4 GU toxicity was observed. CONCLUSION: Neoadjuvant and concomitant EV with high-dose 3D-CRT is well tolerated in patients with unfavorable-risk prostate cancer. Although the incidence of modest (grade 2) late GI and GU toxicities seem to be increased compared with 3D-CRT alone or in combination with androgen ablation therapy, no severe toxicities were encountered with this regimen.

Cloning and functional expression of a brain G-protein-coupled ATP receptor.

A cDNA encoding a novel member of the G-protein-coupled receptor (GCR) superfamily, an ATP receptor, has been isolated from an embryonic chick whole brain cDNA library by hybridization screening. The encoded protein has a sequence of 362 amino acids (41 kDa) and shares no more than 27% amino acid identity with any known GCR. When expressed as a complementary RNA (cRNA) in Xenopus oocytes a slowly-developing inward current was observed in response to application of ATP. The pharmacology of this expressed protein defines it as a P2Y purinoceptor.

Redox modulation of GABAA receptors obscured by Zn2+ complexation.

Redox reagents are thought to modulate gamma-Aminobutyric acid type A (GABA(A)) receptors by regulating the redox state of the N-terminal disulphide bridge. Examining the redox sensitivity of recombinant GABA(A) receptors in human embryonic kidney cells, using whole-cell patch clamp techniques, revealed that alpha1beta2(H267A) and alpha1beta2gamma2 receptors, which are both less sensitive to Zn(2+) and H(+) modulation, ablated the potentiating effect of the reducing agent, dithiothreitol (DTT) seen for alpha1beta2 receptors. This effect could result from disruption to the redox signal transduction pathway or be due to DTT chelating Zn(2+) from its H267 inhibitory binding site, consequently potentiating GABA-activated currents in alpha1beta2 but not alpha1beta2(H267A) or alpha1beta2gamma2 receptors. A Zn(2+) chelating agent, tricine, potentiated GABA currents for the alphabeta constructs and vertically displaced GABA dose-response curves, suggesting that these receptors are subject to some inhibition by basal Zn(2+). Tricine, did not affect the GABA currents of either alpha1beta2(H267A) or alpha1beta2gamma2 receptors but did prevent the potentiation by 2 mM DTT and reduced the potentiation caused by 10 mM DTT on alpha1beta2 receptors. Thus, at low concentrations of DTT, a substantial component of the potentiation probably occurs via Zn(2+) chelation from H267 in the ion channel. In contrast, at higher DTT concentrations, it is more likely to be acting as a redox agent, which modulates both alphabeta and alphabetagamma subunit receptors.

m-sulphonate benzene diazonium chloride: a novel GABAA receptor antagonist.

A previously identified irreversible affinity label for the gamma-aminobutyric acid (GABA) binding site in rat brain membranes, m-sulphonate benzene diazonium chloride (MSBD), was characterized in functional studies using patch clamp and two-electrode voltage clamp recording techniques. MSBD did not exhibit any agonist activity on native GABAA receptors in cultured sympathetic ganglionic neurones but acted as an antagonist of GABA-induced membrane currents. Recombinant GABAA receptors composed of alpha 1, beta 1 and gamma 2S subunits were expressed in Xenopus oocytes following microinjection with cDNAs. Equilibrium dose-response curve analyses established that MSBD was a partially reversible, apparently non-competitive GABAA receptor antagonist. The IC50 for MSBD was estimated from an inhibition curve as 87 +/- 3 microM. In addition, the onset and recovery from MSBD-induced inhibition was independent of GABAA receptor activation. The relatively simple structure of this novel GABAA receptor antagonist, MSBD, is compared with known agonists and antagonists at the GABAA receptor. MSBD may be a useful pharmacological tool which could be used to deduce further information about the structure and function of agonist and antagonist binding sites on the GABAA receptor.