Involvement of cholinergic nicotinic receptors in the menthol-induced gastric relaxation

We have previously demonstrated that menthol reduces murine gastric tone in part through a neural mechanism, involving adrenergic pathways and reduction of ongoing release of acetylcholine from enteric nerves. In the present study we aimed to verify whether the gastric relaxation to menthol may be triggered by interaction with neural receptors or ionic channels proteins, such as transient receptor potential (TRP)-melastatin8 (TRPM8), TRP-ankyrin 1 (TRPA1), 5-hydroxytriptamine 3 (5-HT3) receptor or cholinergic nicotinic receptors. Spontaneous mechanical activity was detected in vitro as changes in intraluminal pressure from isolated mouse stomach. Menthol (0.3-30 mM) induced gastric relaxation which was not affected by 5-benzyloxytryptamine, a TRPM8 receptor antagonist, HC030031, a TRPA1 channel blocker. In addition, allylisothiocyanate, a TRPA1 agonist, but not (2S,5R)-2-Isopropyl-N-(4-methoxyphenyl)-5-methylcyclohexanecarboximide, a selective TRPM8 agonist, induced gastric relaxation. Genic expression of TRPA1, but not of TRPM8, was revealed in mouse stomach. Indeed, menthol-induced gastric relaxation was significantly reduced by hexamethonium, cholinergic nicotinic receptor antagonist. Menthol, at concentrations that failed to affect gastric tone, reduced the contraction induced by dimethylphenylpiperazinium, nicotinic receptor agonist. The joint application of hexamethonium and atropine, muscarinc receptor antagonist, or hexamethonium and phentholamine, α-adrenergic receptor antagonist, did not produce any additive reduction of the relaxant response to menthol. Lastly, ondansetron, a 5-HT3 receptor antagonist, was ineffective. In conclusion, our study suggests that nicotinic receptors, but not TRP and 5-HT3 receptors, are molecular targets for menthol inducing murine gastric relaxation, ultimately due to the reduction of acetylcholine release from enteric nerves.

Direct spectroscopic observation of a shallow hydrogenlike donor state in insulating SrTiO3

We present a direct spectroscopic observation of a shallow hydrogenlike muonium state in SrTiO(3) which confirms the theoretical prediction that interstitial hydrogen may act as a shallow donor in this material. The formation of this muonium state is temperature dependent and appears below ∼ 70K. From the temperature dependence we estimate an activation energy of ∼ 50 meV in the bulk and ∼ 23 meV near the free surface. The field and directional dependence of the muonium precession frequencies further supports the shallow impurity state with a rare example of a fully anisotropic hyperfine tensor. From these measurements we determine the strength of the hyperfine interaction and propose that the muon occupies an interstitial site near the face of the oxygen octahedron in SrTiO(3). The observed shallow donor state provides new insight for tailoring the electronic and optical properties of SrTiO(3)-based oxide interface systems.

GLP-2: what do we know? What are we going to discover?

Glucagon-like peptide 2 [GLP-2] is a 33-amino acid peptide released from the mucosal enteroendocrine L-cells of the intestine. The actions of GLP-2 are transduced by the GLP-2 receptor [GLP-2R], which is localized in the neurons of the enteric nervous system but not in the intestinal epithelium, indicating an indirect mechanism of action. GLP-2 is well known for its trophic role within the intestine and interest in GLP-2 is now reviving based on the approval of the GLP-2R agonist for treatment of short bowel syndrome [SBS]. Recently it also seems to be involved in glucose homeostasis. The aim of this review is to outline the importance of neuroendocrine peptides, specifically of GLP-2 in the enteric modulation of the gastrointestinal function and to focus on new works in order to present an innovative picture of GLP-2.

The use of double lasso, fully covered self-expandable metal stents with new "anchoring flap" system in the treatment of benign biliary diseases

BACKGROUND

Many benign biliary diseases (BBD) can be treated with fully covered, self-expandable metal stents (FCSEMS) but stent migration occurs in up to 35.7 %. The aim of this study was to prospectively assess the rate of, safety and effectiveness and stent migration of a new biliary FCSEMS with an anti-migration flap (FCSEMS-AF) in patients with BBD.

PATIENTS AND METHODS

This was a prospective study from four Italian referral endoscopy centers of 32 consecutive patients (10 females and 22 males; mean age: 60.1 ± 14.8 years; range: 32-84 years) with BBD who were offered endoscopic placement of a FCSEMS-AF as first-line therapy.

RESULTS

Were 24 strictures and 8 leaks. Stent placement was technically successful in 32/32 patients (100 %). Immediate clinical improvement was seen in all 32 patients (100 %). One late stent migration occurred (3.3 %). FCSEMS-AF were removed from 30 of the 32 patients (93.7 %) at a mean (± SD) of 124.4 ± 84.2 days (range: 10-386 days) after placement. All patients remained clinically and biochemically well at 1- and 3-month follow-up. One patient (3.3 %) with a post-laparoscopic cholecystectomy stricture developed distal stent migration at 125 days.

CONCLUSION

This new FCSEMS with anti-migration flap seems to be a safe and effective first-line treatment option for patients with BBD.

Direct observation of the spin texture in SmB6 as evidence of the topological Kondo insulator

Topological Kondo insulators have been proposed as a new class of topological insulators in which non-trivial surface states reside in the bulk Kondo band gap at low temperature due to strong spin-orbit coupling. In contrast to other three-dimensional topological insulators, a topological Kondo insulator is truly bulk insulating. Furthermore, strong electron correlations are present in the system, which may interact with the novel topological phase. By applying spin- and angle-resolved photoemission spectroscopy, here we show that the surface states of SmB6 are spin polarized. The spin is locked to the crystal momentum, fulfilling time reversal and crystal symmetries. Our results provide strong evidence that SmB6 can host topological surface states in a bulk insulating gap stemming from the Kondo effect, which can serve as an ideal platform for investigating of the interplay between novel topological quantum states with emergent effects and competing orders induced by strongly correlated electrons.

Superconductivity in a new layered bismuth oxyselenide: LaO(0.5)F(0.5)BiSe₂

We report superconductivity at T(c) ≈ 2.6 K in a new layered bismuth oxyselenide LaO(0.5)F(0.5)BiSe2 with the ZrCuSiAs-type structure composed of alternating superconducting BiSe2 and blocking LaO layers. The superconducting properties of LaO(0.5)F(0.5)BiSe2 were investigated by means of dc magnetization, resistivity and muon-spin rotation experiments, revealing the appearance of bulk superconductivity with a rather large superconducting volume fraction of ≈ 70% at 1.8 K.

Exogenous glucagon-like peptide 1 reduces contractions in human colon circular muscle

Glucagon-like peptide 1 (GLP1) is a naturally occurring peptide secreted by intestinal L-cells. Though its primary function is to serve as an incretin, GLP1 reduces gastrointestinal motility. However, only a handful of animal studies have specifically evaluated the influence of GLP1 on colonic motility. Consequently, the aims of this study were to investigate the effects induced by exogenous GLP1, to analyze the mechanism of action, and to verify the presence of GLP1 receptors (GLP1Rs) in human colon circular muscular strips. Organ bath technique, RT-PCR, western blotting, and immunofluorescence were used. In human colon, exogenous GLP1 reduced, in a concentration-dependent manner, the amplitude of the spontaneous contractions without affecting the frequency and the resting basal tone. This inhibitory effect was significantly reduced by exendin (9-39), a GLP1R antagonist, which per se significantly increased the spontaneous mechanical activity. Moreover, it was abolished by tetrodotoxin, a neural blocker, or Nω-nitro-l-arginine - a blocker of neuronal nitric oxide synthase (nNOS). The biomolecular analysis revealed a genic and protein expression of the GLP1R in the human colon. The double-labeling experiments with anti-neurofilament or anti-nNOS showed, for the first time, that immunoreactivity for the GLP1R was expressed in nitrergic neurons of the myenteric plexus. In conclusion, the results of this study suggest that GLP1R is expressed in the human colon and, once activated by exogenous GLP1, mediates an inhibitory effect on large intestine motility through NO neural release.

Efficacy and acceptability of sodium picosulphate/magnesium citrate vs low-volume polyethylene glycol plus ascorbic acid for colon cleansing: a randomized controlled trial

AIM

The study compared the efficacy, safety and tolerability of a low-volume picosulphate/magnesium citrate preparation with that of polyethylene glycol plus ascorbic acid (PEG + ASC) in a randomized clinical trial (RCT).

METHOD

A multicentre randomized, single-blinded study was designed. Adult outpatients undergoing colonoscopy received either picosulphate/magnesium citrate (Group 1) or PEG + ASC (Group 2). Bowel cleansing was assessed using the Boston Bowel Preparation Scale (BBPS) and rated as adequate if ≥ 2 in each segment. Patient acceptance, satisfaction and related symptoms were recorded.

RESULTS

Two-hundred and eighty-five patients were included. Preparation was adequate in 75.7% of patients in Group 1 and in 76.5% of patients in Group 2. The mean BBPS scores for the entire colon and for the right colon were comparable between groups. In addition, 97.1% patients in Group 1 and 84.8% in Group 2 reported no or mild discomfort (P < 0.0003) and 97.8% and 83.4% expressed their willingness to repeat the preparation (P < 0.0001). Palatability was better in Group 1, whereas related symptoms occurred more frequently in Group 2. Regardless of which preparation was used, the split regimen was associated with better cleansing compared with the same-day method (OR = 3.39; 95% CI: 1.1-10.4; P = 0.03). Other predictors of poor cleansing were comorbidity, discomfort during preparation and incomplete (< 75%) preparation.

CONCLUSION

Both picosulphate/magnesium citrate and PEG + ASC are effective for bowel preparation. Tolerability and palatability are better for picosulphate/magnesium citrate. A split schedule is associated with higher cleansing quality also for low-volume regimens.

Interpreting elevated fetal hemoglobin in pathology and health at the basic laboratory level: new and known γ- gene mutations associated with hereditary persistence of fetal hemoglobin

Fetal hemoglobin may be slightly or significantly elevated in post-natal life due to a number of causes. We report two novel mutations found on the promoter of the Aγ gene and summarize all common and rare determinants associated with hereditary persistence of fetal hemoglobin (HPFH) described thus far. Hematological and molecular analysis of the Aγ globin gene in two cases of HPFH. Comparison of the novel cases with all those described in the literature. We have found two novel mutations in three Italian patients with HbF values between 5.9% and 6.5% without an elevated HbA(2) and with normal hemoglobin parameters. In two probands (mother and son), a -197 C>T transition was observed, while in a single individual, a -113 A>G transition was present on the distal CCAAT box of the Aγ gene. As no other abnormalities were present in both γ-gene promoters and the changes are located on regulatory sequences, we may conclude that these mutations are responsible for the HPFH phenotype shown by the carriers. The laboratory should be able to discriminate between elevated HbF due to artifacts or to serious causes including bone marrow malignancies, aplastic anemia, and β-thalassemia major or recessive traits such as β-thalassemia minor, δβ-thalassemia, or nonpathological conditions induced by mutations or polymorphisms of the γ-gene promoters that may even be beneficial when present in patients with thalassemia major or sickle cell disease and, in particular, when these patients are treated with hydroxyurea.

Glucagon-like peptide-2 and mouse intestinal adaptation to a high-fat diet

Endogenous glucagon-like peptide-2 (GLP2) is a key mediator of refeeding-induced and resection-induced intestinal adaptive growth. This study investigated the potential role of GLP2 in mediating the mucosal responses to a chronic high-fat diet (HFD). In this view, the murine small intestine adaptive response to a HFD was analyzed and a possible involvement of endogenous GLP2 was verified using GLP2 (3-33) as GLP2 receptor (GLP2R) antagonist. In comparison with animals fed a standard diet, mice fed a HFD for 14 weeks exhibited an increase in crypt-villus mean height (duodenum, 27.5±3.0%; jejunum, 36.5±2.9%; P<0.01), in the cell number per villus (duodenum, 28.4±2.2%; jejunum, 32.0±2.9%; P<0.01), and in Ki67-positive cell number per crypt. No change in the percent of caspase-3-positive cell in the villus-crypt was observed. The chronic exposure to a HFD also caused a significant increase in GLP2 plasma levels and in GLP2R intestinal expression. Daily administration of GLP2 (3-33) (30-60  ng) for 4 weeks did not modify the crypt-villus height in control mice. In HFD-fed mice, chronic treatment with GLP2 (3-33) reduced the increase in crypt-villus height and in the cell number per villus through reduction of cell proliferation and increase in apoptosis. This study provides the first experimental evidence for a role of endogenous GLP2 in the intestinal adaptation to HFD in obese mice and for a dysregulation of the GLP2/GLP2R system after a prolonged HFD.

Two-dimensional superfluid density in an alkali metal-organic solvent intercalated iron selenide superconductor Li(C5H5N)0.2Fe2Se2

We report the low-temperature electronic and magnetic properties of the alkali metal-organic solvent intercalated iron selenide superconductor Li(C5H5N)0.2Fe2Se2 using muon-spin-spectroscopy measurements. The zero-field muon spin relaxation (μSR) results indicate that nearly half of the sample is magnetically ordered and spatially phase separated from the superconducting region. The transverse-field μSR results reveal that the superfluid density of Li(C5H5N)0.2Fe2Se2 is two dimensional in nature. The temperature dependence of the penetration depth λ(T) can be explained using a two-gap s-wave model. This implies that, despite the 2D nature of the superfluid density, the symmetry of the superconducting gap remains unaltered to the parent compound FeSe.

Structural and magnetic phase transitions in triclinic Ca10(FeAs)10(Pt3As8)

We report the structural and magnetic phase transitions of triclinic Ca10(FeAs)10(Pt3As8), which is the parent compound of the 1038-type iron-arsenide superconductors. High-resolution x-ray diffraction reveals splitting of the in-plane (a,b) lattice parameters at T(s) ≈ 120 K. Platinum-doping weakens the distortion and shifts the transition temperature to 80 K in Ca10(Fe(1-x)Pt(x)As)10(Pt3As8) with x = 0.03. μSR experiments show the onset of magnetic order near T and a broad magnetic phase transition. The structural transition involves no reduction of the space group symmetry in contrast to the other parent compounds of iron-arsenide superconductors; nevertheless the local fourfold symmetry of the FeAs-layers in Ca10(FeAs)10(Pt3As8) is broken.

Dynamical splayed ferromagnetic ground state in the quantum spin ice Yb(2)Sn(2)O(7)

From magnetic, specific heat, (170)Yb Mössbauer effect, neutron diffraction, and muon spin relaxation measurements on polycrystalline Yb(2)Sn(2)O(7), we show that below the first order transition at 0.15 K all of the Yb(3+) ions are long-range magnetically ordered and each has a moment of 1.1 μ(B) which lies at ≃ 10° to a common fourfold cubic axis. The four sublattice moments have four different directions away from this axis and are therefore noncoplanar. We term this arrangement splayed ferromagnetism. This ground state has a dynamical component with a fluctuation rate in the megahertz range. The net ferromagnetic exchange interaction has an anisotropy that favors the local threefold axis. We discuss our results in terms of the phase diagram proposed by Savary and Balents [Phys. Rev. Lett. 108, 037202 (2012)] for a pyrochlore lattice of Kramers 1/2 effective spins.

Avoided ferromagnetic quantum critical point: unusual short-range ordered state in CeFePO

Cerium 4f electronic spin dynamics in single crystals of the heavy-fermion system CeFePO is studied by means of ac susceptibility, specific heat, and muon-spin relaxation (μSR). Short-range static magnetism occurs below the freezing temperature T(g) ≈ 0.7 K, which prevents the system from accessing a putative ferromagnetic quantum critical point. In the μSR, the sample-averaged muon asymmetry function is dominated by strongly inhomogeneous spin fluctuations below 10 K and exhibits a characteristic time-field scaling relation expected from glassy spin dynamics, strongly evidencing cooperative and critical spin fluctuations. The overall behavior can be ascribed neither to canonical spin glasses nor other disorder-driven mechanisms.

Primary anastomosis vs nonrestorative resection for perforated diverticulitis with peritonitis: a prematurely terminated randomized controlled trial

AIM

This randomized controlled trial (RCT) was performed to test the hypothesis that adverse event rates following primary anastomosis (PRA) are not inferior to those following nonrestorative colon resection for perforated diverticulitis with peritonitis.

METHOD

Patients admitted for perforated diverticulitis with peritonitis were randomly assigned to PRA (left colon resection with PRA and loop ileostomy) or nonrestorative colon resection (left colon resection with end colostomy). The endpoint was adverse events defined as mortality and morbidity following PRA or nonrestorative colon resection and stoma reversal. The estimated sample size was 300 patients in each study arm (alpha 0.10; 90% power).

RESULTS

During a 9-year period, 90 patients were randomly assigned to undergo PRA or nonrestorative colon resection in 14 centres in eight countries. Thirty-four PRA patients were comparable to 56 nonrestorative colon resection patients for age (P = 0.481), gender (P = 0.190), APACHE III (P = 0.281), Hinchey stage III vs IV (P = 0.394) and Mannheim Peritonitis Index (P = 0.145). There were no differences in operating time (P = 0.231), surgeries performed at night (P = 0.083), open vs laparoscopic approach (P = 0.419) and litres of peritoneal irrigation (P = 0.096). There was no significant difference in mortality (2.9 vs 10.7%; P = 0.247) and morbidity (35.3 vs 46.4%; P = 0.38) following PRA or nonrestorative colon resection. After a similar lag time (P = 0.43), 64.7% of PRA patients and 60% of nonrestorative colon resection patients underwent stoma reversal (P = 0.659). Adverse event rates following stoma reversal differed significantly after PRA and reversal of nonrestorative resection (4.5 vs 23.5%; P = 0.0589).

CONCLUSION

No conclusions may be drawn on preference of one treatment over another from this RCT because it was prematurely terminated following accrual of 15% of its sample size.

Resect and discard strategy in clinical practice: a prospective cohort study

BACKGROUND AND STUDY AIMS

Narrow-band imaging (NBI) has shown promising results in discriminating adenomatous from non-adenomatous colonic polyps. In patients with small polyps (< 10  mm), the application of NBI within a "resect and discard" strategy, might allow post-polypectomy surveillance intervals to be determined independently from histopathology. The aim of the present study was to assess the feasibility and safety of this approach in routine clinical practice.

PATIENTS AND METHODS

Consecutive colonoscopy outpatients with one or more polyps smaller than 10  mm were prospectively included. Each polyp was categorized by the endoscopist as adenoma or non-adenoma according to simplified NBI criteria, and future post-polypectomy surveillance interval was assigned accordingly. Following histopathology, post-polypectomy surveillance interval was subsequently re-assigned, and the accordance between endoscopy- and histology-directed surveillance strategies was calculated.

RESULTS

Among 942 colonoscopy patients, 286 (30.4 %) with only small polyps were included. In total, 511 small polyps were evaluated; 350 (68.5 %) were adenomas and 18 of these (5.1 %) had histologic features of advanced neoplasia. For the in vivo diagnosis of adenoma, NBI sensitivity, specificity, accuracy, and positive and negative likelihood ratios were 94.9 %, 65.8 %, 85.7 %, 2.80, and 0.08, respectively. The endoscopy-directed surveillance strategy was in accordance with the histology-directed strategy in 237 of 286 patients (82.9 %). In 9.8 % and 7.3 % patients, the endoscopy-directed approach would have resulted in early and delayed surveillance, respectively.

CONCLUSIONS

The resect and discard strategy seems to be a viable, safe, and cost-effective approach for the management of patients with small polyps. However, caution in the application of the strategy should be advocated for patients with polyps 6 - 9  mm in size and those with right-sided lesions, due to their malignant potential. The study was registered on Clinicaltrials.gov (NCT01462123).

Kapellasite: a kagome quantum spin liquid with competing interactions

Magnetic susceptibility, NMR, muon spin relaxation, and inelastic neutron scattering measurements show that kapellasite, Cu3Zn(OH)6Cl2, a geometrically frustrated spin-1/2 kagome antiferromagnet polymorphic with herbertsmithite, is a gapless spin liquid showing unusual dynamic short-range correlations of noncoplanar cuboc2 type which persist down to 20 mK. The Hamiltonian is determined from a fit of a high-temperature series expansion to bulk susceptibility data and possesses competing exchange interactions. The magnetic specific heat calculated from these exchange couplings is in good agreement with experiment. The temperature dependence of the magnetic structure factor and the muon relaxation rate are calculated in a Schwinger-boson approach and compared to experimental results.