Linoleic acid in diets of mice increases total endocannabinoid levels in bowel and liver: modification by dietary glucose

AIM

Linoleic acid (LA) is an essential fatty acid involved in the biosynthesis of arachidonic acid and prostaglandins. LA is known to induce obesity and insulin resistance. In this study, two concentrations of LA with or without added glucose (G) were fed to mice to investigate their effects on endocannabinoid (EC) biology.

MATERIALS AND METHODS

Four groups of C57BL/6 mice were provided with diets containing 1% or 8% LA with or without added G (LAG) for 8 weeks. Body weights, food intake, circulating glucose and insulin levels were measured throughout the study. Following euthanasia, plasma, bowel and hepatic ECs, monoacylglycerol lipase and fatty acid amide hydroxylase protein levels (enzymes responsible for EC degradation) and transcriptional activity of PPARα in liver were quantified. Liver was probed for evidence of insulin receptor activity perturbation.

RESULTS

Increasing dietary LA from 1% to 8% significantly increased circulating, small bowel and hepatic ECs. 1%LAG fed mice had lowest feed efficiency, and only liver levels of both ECs were reduced by addition of G. Addition of G to 1% LA diets resulted in elevated monoacylglycerol lipase and fatty acid amide hydroxylase protein levels (p < 0.001 and p < 0.001, respectively) in liver due to increased transcriptional activity of PPARα (p < 0.05). The reduced EC levels with addition of G also correlated with a measure of enhanced insulin action.

CONCLUSION

In conclusion, body weight of mice is influenced by the source of calorie intake. Furthermore, tissue EC/g are dependent on tissue-specific synthesis and degradation that are modulated by dietary LA and G which also influence food efficiency, and down-stream insulin signalling pathways. The findings could potentially be useful information for weight management efforts in humans.

RUBBER BLEND AND FILLER EFFECTS ON DAMAGE MECHANISMS UNDER MONOTONIC AND FATIGUE LOADING

To appreciate the nature and failure mode of elastomers, it is important to understand their fracture behavior. There are various factors that influence the fracture characteristics of rubber vulcanizates, namely, temperature, strain rate, and type of loading. In this research, fracture behavior of gum and carbon black filled rubber compounds having 100 parts natural rubber (NR), polybutadiene rubber (BR), and 60–40 NR/BR blend is reported. The effect of strain rate, temperature, and carbon black on tensile strength, fracture/tearing energy, and crack growth is detailed. Based on our investigation, we have determined BR to be more sensitive to temperature change than NR. Also, contrasting behavior is observed for gum and filled polymer blends.

Tensile and fatigue tests were performed on a universal testing machine and tear and fatigue analyzer, respectively. The tested samples were also examined in the scanning electron microscope to obtain high-resolution imaging of fracture surfaces. The samples tested under monotonic loading provide smoother surfaces by showing the phase separation in comparison with fatigue loading.

Azimuthal Anisotropy of Heavy-Flavor Decay Electrons in p-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

Angular correlations between heavy-flavor decay electrons and charged particles at midrapidity (|η|<0.8) are measured in p-Pb collisions at sqrt[s_{NN}]=5.02  TeV. The analysis is carried out for the 0%-20% (high) and 60%-100% (low) multiplicity ranges. The jet contribution in the correlation distribution from high-multiplicity events is removed by subtracting the distribution from low-multiplicity events. An azimuthal modulation remains after removing the jet contribution, similar to previous observations in two-particle angular correlation measurements for light-flavor hadrons. A Fourier decomposition of the modulation results in a positive second-order coefficient (v_{2}) for heavy-flavor decay electrons in the transverse momentum interval 1.5<p_{T}<4  GeV/c in high-multiplicity events, with a significance larger than 5σ. The results are compared with those of charged particles at midrapidity and those of inclusive muons at forward rapidity. The v_{2} measurement of open heavy-flavor particles at midrapidity in small collision systems could provide crucial information to help interpret the anisotropies observed in such systems.

Microscopic understanding of electrocatalytic reduction of CO2 on Pd-polyaniline composite: an ab initio study

The reaction mechanism for the electroreduction of CO₂ on polyaniline (PANI) and its composite with a single palladium atom (Pd/PANI) has been investigated employing ab initio density functional theory. It is observed that the Pd/PANI composite can capture and activate CO₂ more efficiently than those for the cases of individual systems (PANI and Pd atom). Moreover, it is found that both PANI and Pd/PANI show high selectivity for the formation of formic acid (HCOOH) over the methanol (CH₃OH) production. The electroreduction of CO₂ towards formic acid (HCOOH) follows two different pathways, depending on the catalyst: on PANI the formation of HCOOH occurs through the *COOH intermediate, whereas for the case of Pd/PANI, the same reaction proceeds through the formation of formate (*OCHO). While the formation of CH₃OH from CO₂ on PANI is not feasible, electroreduction of CO₂ towards CH₃OH on Pd/PANI occurs through the formation of CO.

Traction cytometry: regularization in the Fourier approach and comparisons with finite element method

Traction forces exerted by adherent cells are quantified using displacements of embedded markers on polyacrylamide substrates due to cell contractility. Fourier Transform Traction Cytometry (FTTC) is widely used to calculate tractions but has inherent limitations due to errors in the displacement fields; these are mitigated through a regularization parameter (γ) in the Reg-FTTC method. An alternate finite element (FE) approach computes tractions on a domain using known boundary conditions. Robust verification and recovery studies are lacking but essential in assessing the accuracy and noise sensitivity of the traction solutions from the different methods. We implemented the L2 regularization method and defined a maximum curvature point in the traction with γ plot as the optimal regularization parameter (γ*) in the Reg-FTTC approach. Traction reconstructions using γ* yield accurate values of low and maximum tractions (Tmax) in the presence of up to 5% noise. Reg-FTTC is hence a clear improvement over the FTTC method but is inadequate to reconstruct low stresses such as those at nascent focal adhesions. FE, implemented using a node-by-node comparison, showed an intermediate reconstruction compared to Reg-FTTC. We performed experiments using mouse embryonic fibroblast (MEF) and compared results between these approaches. Tractions from FTTC and FE showed differences of ∼92% and 22% as compared to Reg-FTTC. Selection of an optimum value of γ for each cell reduced variability in the computed tractions as compared to using a single value of γ for all the MEF cells in this study.

Low-Bandgap Cs4 CuSb2 Cl12 Layered Double Perovskite: Synthesis, Reversible Thermal Changes, and Magnetic Interaction

Double perovskites (DPs) with a generic formula A2 M'(I)MIII X6 (A and M are metal ions, and X=Cl, Br, I) are now being explored as potential alternatives to Pb-halide perovskites for solar cells and other optoelectronic applications. However, these DPs typically suffer from wide (≈3 eV) and/or indirect band gaps. In 2017, a new structural variety, namely layered halide DP Cs4 CuSb2 Cl12 (CCSC) with bivalent CuII ion in the place of M'(I) was reported, which exhibit a band gap of approximately 1 eV. Here, we report a mechanochemical synthesis of CCSC, its thermal and chemical stability, and magnetic response of CuII d9 electrons controlling the optoelectronic properties. A simple grinding of precursor salts at ambient conditions provides a stable and scalable product. CCSC is stable in water/acetone solvent mixtures (≈30 % water) and many other polar solvents unlike Pb-halide perovskites. It decomposes to Cs3 Sb2 Cl9 , Cs2 CuCl4 , and SbCl3 at 210 °C, but the reaction can be reversed back to produce CCSC at lower temperatures and high humidity. A long-range magnetic ordering is observed in CCSC even at room temperature. The role of such magnetic ordering in controlling the dispersion of the conduction band, and therefore, controlling the electronic and optoelectronic properties of CCSC has been discussed.

D-Meson Azimuthal Anisotropy in Midcentral Pb-Pb Collisions at sqrt[s]_{NN}=5.02 TeV

The azimuthal anisotropy coefficient v_{2} of prompt D^{0}, D^{+}, D^{*+}, and D_{s}^{+} mesons was measured in midcentral (30%-50% centrality class) Pb-Pb collisions at a center-of-mass energy per nucleon pair sqrt[s_{NN}]=5.02  TeV, with the ALICE detector at the LHC. The D mesons were reconstructed via their hadronic decays at midrapidity, |y|<0.8, in the transverse momentum interval 1<p_{T}<24  GeV/c. The measured D-meson v_{2} has similar values as that of charged pions. The D_{s}^{+} v_{2}, measured for the first time, is found to be compatible with that of nonstrange D mesons. The measurements are compared with theoretical calculations of charm-quark transport in a hydrodynamically expanding medium and have the potential to constrain medium parameters.

One-Pot Tandem Hiyama Alkynylation/Cyclizations by Palladium(II) Acyclic Diaminocarbene (ADC) Complexes Yielding Biologically Relevant Benzofuran Scaffolds

A series of palladium acyclic diaminocarbene (ADC) complexes of the type cis-[(R¹NH)(R²)methylidene]PdCl₂(CNR¹) [R¹ = 2,4,6-(CH₃)₃C₆H₂: R² = NC₅H₁₀ (2); NC₄H₈ (3); NC₄H₈O (4)] were used not only to perform the C_sp² -C_sp Hiyama coupling between aryl iodide and triethoxysilylalkynes but also to subsequently carry out the one-pot tandem Hiyama alkynylation/cyclization reaction between 2-iodophenol and triethoxysilylalkynes, giving a convenient time-efficient access to the biologically relevant benzofuran compounds. The palladium ADC complexes (2-4) were conveniently synthesized by the nucleophilic addition of secondary amines, namely, piperidine, pyrrolidine, and morpholine on the cis-{(2,4,6-(CH₃)₃C₆H₂)NC}₂PdCl₂ in moderate yields (ca. 61-66%).

Cyanosilylation of Aromatic Aldehydes by Cationic Ruthenium(II) Complexes of Benzimidazole-Derived O-Functionalized N-Heterocyclic Carbenes at Ambient Temperature under Solvent-Free Conditions

A series of ruthenium complexes, namely, [{1-(N-R₁-2-acetamido)-3-(R₂)-benzimidazol-2-ylidine}Ru(p-cymene)Cl]Cl, where {R₁ = 2,6-(i-Pr)₂C₆H₃, R₂ = i-Pr (1c); R₁ = 2,6-(i-Pr)₂C₆H₃, R₂ = Et (2c); R₁ = 2,4,6-(CH₃)₃C₆H₂, R₂ = Et (3c)}, of benzimidazole-derived N/O-functionalized N-heterocyclic carbene ligands successfully carried out the cyanosilylation reaction of aromatic aldehydes and heteroaryl aldehydes with trimethylsilyl cyanide, providing good to excellent yields (ca. 60-95%) at room temperature under solvent-free condition. The ruthenium (1-3)c complexes were synthesized from the silver (1-3)b analogues in ca. 67-80% yields. The silver (1-3)b complexes exhibited an argentophilic d ¹⁰···d ¹⁰ interaction in its dinuclear macrometallacyclic motif, as observed by a short Ag···Ag contact of 3.1894(3) Å in single-crystal X-ray diffraction studies for a representative silver complex 2b and also in photoluminescence studies that showed characteristic emission band(s) at ca. 534-536 nm in the CHCl₃ solution and at ca. 482-487 and 530-533 nm in the solid state.

Healing of Circular Defects in the Rabbit Medial Meniscus Can Occur Spontaneously and Is not Improved by Intra-Articular Hyaluronic Acid

The aim of this study was to determine the effects of intra-articular hyaluronic acid on meniscal healing. Circular defects, 1.0 mm in diameter, were made in the anterior third of the medial meniscus in rabbits. In one joint, 0.4 ml hyaluronic acid (Healon®) was instilled, and in the contralateral (control) joint, 0.4 ml Ringer’s saline. Four rabbits were killed after four, eight and 12 weeks and the menisci examined histologically. By eight weeks most of the lesions had healed by filling with hyaline-like cartilage. Healing was not improved by hyaluronic acid treatment. The repair tissue stained strongly with alcian blue, and the presence of type II collagen, keratan sulphate, and chondroitin sulphate was demonstrated by immunohistochemical localisation. In contrast to the circular defects, longitudinal incisions made in the medial menisci of a further six rabbits did not show any healing after 12 weeks, indicating that the shape of the lesion largely determined the potential for healing.

The effect of hyaluronic acid on meniscal healing was tested in a rabbit model. With one millimeter circular lesions in the medial meniscus, healing by filling with hyalinelike cartilage was not significantly affected by the application of hyaluronic acid intra-articularly at the time of surgery, compared to saline controls, as assessed histologically four, eight and 12 weeks after the operation.

A Comparative Study of the Composition of Discs and of Proteoglycans from Different Spinal Levels of Sheep

Compositional analyses were undertaken on lumbar (L2L3 - L5L6) and lumbosacral (L6S1) intervertebral disc tissues from young adult (2-year-old) merino wethers. The proteoglycan level in the nucleus pulposus of the lumbosacral disc was significantly lower than that found in the nucleus pulposus of lumbar levels (p<0.05). The annulus fibrosus was richer in collagen compared to the nucleus pulposus in all discs examined, and the lumbosacral disc consistently had both higher annulus fibrosus and nucleus pulposus collagen levels than lumbar discs (p<0.05). Aggregation of the high buoyant density proteoglycans, with hyaluronic acid, was generally higher in annulus fibrosus proteogly-cans than nucleus pulposus proteogly-cans irrespective of the spinal level examined. Examination of the inter-vertebral disc proteoglycans, by composite agarose polyacrylamide gel electrophoresis, demonstrated three proteoglycan subpopulations and that the nucleus pulposus generally contained a greater proportion of higher mobility more polydisperse proteoglycan species than the annulus fibrosus.

Ovine intervertebral disc collagen and proteoglycan composition varies with spinal level. Lumbosacral intervertebral discs contain greater levels of non-aggregatable more polydisperse proteoglycan species than lumbar discs, which may reflect their relative proximities to the pelvis and the variable levels of stress experienced by the respective tissues.

The Effect of Total Meniscectomy versus Caudal Pole Hemimeniscectomy on the Stifle Joint of the Sheep

Total medial meniscectomy and caudal pole hemimeniscectomy were performed on the stifle joints of twelve sheep. The two forms of meniscectomy produced a comparable degree of postoperative lameness that resolved within two weeks of the operations. After six months the sheep were euthanatised and the stifle joints examined. Fibrous tissue that replaced the excised meniscus in the total meniscectomy group did not cover as much of the medial tibial condyle as the residual cranial pole and caudal fibrous tissue observed following hemimeniscectomy. The articular cartilage from different regions within the joints was examined for gross and histological evidence of degeneration. Analyses of the articular cartilage for water content, glycosaminoglycan composition and DNA content were performed. The proteoglycan synthesis and release from explanted articular cartilage samples in tissue culture were also measured. There were significant pathological changes in the medial compartment of all meniscectomised joints. The degree of articular cartilage degeneration that was observed following total meniscectomy and caudal pole meniscectomy was similar. Caudal pole hemimeniscectomy, involving transection of the meniscus, causes the same degree of degeneration of the stifle joint that occurs following total meniscectomy.

The effect of total medial meniscectomy versus caudal pole hemimeniscectomy on the stifle joint of sheep was studied experimentally. Six months after the operations gross pathology, histopathology, cartilage biochemical analysis and the rate of proteoglycan synthesis in tissue culture were used to compare the articular cartilage harvested from the meniscectomised joints. Degeneration of the articular cartilage from the medial compartment of the joints was present in both of the groups. Caudal pole hemimeniscectomy induces a comparable degree of articular cartilage degeneration to total medial meniscectomy in the sheep stifle joint.

Cardiac tamponade in systemic lupus erythematosus

BACKGROUND

Cardiac tamponade is a rare but life-threatening complication of systemic lupus erythematosus (SLE).

AIMS/OBJECTIVES

To describe incidence, risk factors and treatment of cardiac tamponade in a large cohort of Indian patients with SLE.

METHODS

This retrospective study was conducted at the Department of Rheumatology, IPGMER, Kolkata, India from May 2014 to December 2016 on admitted patients with SLE. Lupus-related serositis was diagnosed after excluding other causes, such as infection, malignancy or heart failure.

RESULTS

Of 409 patients with SLE, pericarditis was diagnosed in 25.4% (104/409) and cardiac tamponade in 5.9% (24/409). Tamponade was the presenting feature of SLE in 50% (12/24). Tamponade occurred in 77.8% (14/18) of large effusions and in 11.63% (10/86) of small-to-moderate effusions. The commonest autoantibody in serum and pericardial fluid was anti-nucleosme antibody. Large pericardial effusion (>20 mm) (Odd's ratio (OR): 93.2, 95% confidence interval (CI): 11.1-782.5, P < 0.001) predicted tamponade. In the subset of patients with small-to-moderate sized pericardial effusion, tamponade was associated with pleuritis (OR: 44.5, 95% CI: 1.6-1243, P = 0.025), anti-nucleosome antibody (OR: 42.9, 95% CI: 1.6-1176, P = 0.026) and size of pericardial effusion (OR: 1.36, 95% CI: 1.04-1.76, P = 0.025). Repeated pericardiocentesis was required in 3 patients and one needed surgical intervention. Immunosuppressives used were: prednisolone with monthly intravenous cyclophosphamide (in 33.33%) and intravenous methylprednisolone with monthly cyclophosphamide (in 50%).

CONCLUSIONS

Pleuritis, anti-nucleosome antibody and size of pericardial effusion predicted development of tamponade. High dose immunosuppression (methylprednisolone and IV cyclophosphamide) alleviated need for surgery in majority.