Oleoylethanolamide inhibits food intake in free-feeding rats after oral administration.

Oleoylethanolamide (OEA) is an endogenous lipid that contributes in important ways to the peripheral regulation of food intake. When administered intraperitoneally, OEA is a potent satiety-inducing anorexiant in rats and mice [Nature 414 (2001) 209; Neuropsycopharmacology 28 (2003) 1311; Nature 425 (2003) 90]. In the present study, we show that oral administration of OEA in pH-sensitive enteric-coated capsules produces a profound and long-lasting inhibition of food intake in free-feeding rats. This effect is accompanied by a marked elevation in OEA levels in the small intestine, but not in brain or muscle.     

Intestinal absorption and biliary secretion of cholesterol in rats with nephrotic syndrome

Background: Nephrotic syndrome (NS) results in hypercholesterolemia which is attributed to increased production and decreased removal of cholesterol-rich lipoproteins. Adjustments in intestinal absorption are reportedly involved in cholesterol homeostatis. We therefore, studied the intestinal absorption and biliary excretion of cholesterol in NS. Methods: We studied intestinal absorption (by in vivo perfusion and in vitro everted sac incubation techniques) and biliary secretion (by common bile duct cannulation) of cholesterol in rats with puromycin-induced NS. The results were compared with those obtained from pair-fed control (PF) animals, those given free access to food (NL) or those fed a hypercholerolemic diet (H-chol group). Micellar solutions of Krebs' phosphate buffer containing trace amounts of [¹⁴C]inulin and [³H]cholesterol, as well as different concentrations of unlabeled cholesterol, were used for absorption studies. Results: The NS and H-chol groups showed severe and comparable hypercholesterolemia. No significant difference was found in the rate of biliary cholesterol secretion among the study groups. Likewise, the rates of in vivo and in vitro cholesterol absorptions in the NS and H-chol groups were comparable with one another and similar to those found in the NL and PF groups. The rate of in vitro cholesterol absorption was directly proportional to its concentration in the incubation media at low concentrations. However, the absorption rate showed a pattern consistent with saturable transport at high cholesterol concentrations in all groups. Conclusions: We conclude that intestinal absorption and biliary secretion of cholesterol are not appreciably influenced by either nephrotic or diet-induced hypercholesterolemia in rats. The data further suggest that cholesterol absorption may be a saturable process.     

Functional, biochemical, and histopathologic consequences of high-dose interleukin-2 administration in rats

A variety of side effects have been reported with the use of interleukin-2 alone or in combination with lymphokine-activated killer cells in patients with disseminated neoplasms. The present study was undertaken to determine the effects of high-dose interleukin-2 administration in normal rats. Sprague-Dawley rats were treated with intravenous recombinant interleukin-2 (900,000 IU/kg/day) for 9 consecutive days. Animals were placed in individual metabolic cages, and arterial blood pressure, food intake, body weight, and urine output were monitored. On day 10, animals were killed by exsanguination, various tissues were harvested, and a variety of hematologic and chemical assays were performed. The results were compared with those of placebo-injected normal control and pair-fed groups. The interleukin-2-treated group exhibited anorexia, weight loss, hypotension, anemia, leukocytosis, lymphocytosis, eosinophilia, hypercalcemia, azotemia, and a marked urinary concentration defect. Histologic examination of various tissues revealed widespread infiltration with mono-nuclear cells and eosinophils in most organs, especially in the lungs and liver of interleukin-2-treated animals. Other abnormalities included severe panlobular hepatitis, hepatocellular necrosis, and thymic involution. Renal involvement was mild and consisted of focal interstitial infiltration by mononuclear cells. According to these observations, administration of high-dose interleukin-2 in normal rats results in a score of significant functional, biochemical, and histologic abnormalities.     

Bottom-up synthesis of graphene films hosting atom-thick molecular-sieving apertures

Incorporation of a high density of molecular-sieving nanopores in the graphene lattice by the bottom-up synthesis is highly attractive for high-performance membranes. Herein, we achieve this by a controlled synthesis of nanocrystalline graphene where incomplete growth of a few nanometer-sized, misoriented grains generates molecular-sized pores in the lattice. The density of pores is comparable to that obtained by the state-of-the-art postsynthetic etching (10¹² cm⁻²) and is up to two orders of magnitude higher than that of molecular-sieving intrinsic vacancy defects in single-layer graphene (SLG) prepared by chemical vapor deposition. The porous nanocrystalline graphene (PNG) films are synthesized by precipitation of C dissolved in the Ni matrix where the C concentration is regulated by controlled pyrolysis of precursors (polymers and/or sugar). The PNG film is made of few-layered graphene except near the grain edge where the grains taper down to a single layer and eventually terminate into vacancy defects at a node where three or more grains meet. This unique nanostructure is highly attractive for the membranes because the layered domains improve the mechanical robustness of the film while the atom-thick molecular-sized apertures allow the realization of large gas transport. The combination of gas permeance and gas pair selectivity is comparable to that from the nanoporous SLG membranes prepared by state-of-the-art postsynthetic lattice etching. Overall, the method reported here improves the scale-up potential of graphene membranes by cutting down the processing steps.

The direct bottom-up synthesis of two-dimensional (2D) films hosting molecular-sieving apertures is a longstanding goal in material chemistry. Materials with a high density of molecular-sized nanopores such as zeolites (1, 2), metal-organic frameworks (MOFs) (3, 4), covalent organic frameworks (5), graphitic carbon nitride (6), and protein channels (7) can be synthesized in a 2D topology, albeit in the form of nanosheets with lateral dimension limited to ∼O (1 µm), which prohibits the realization of porous, unit-cell–thick films by the bottom-up synthesis. On the other hand, the synthesis of high-quality atom-thick polycrystalline films of graphene (8) and hexagonal boron nitride (h-BN) (9) can be carried out in a scalable manner, with the production capacity of graphene films exceeding three million m² in 2017 (10). However, their lattice is impermeable in the absence of a sufficient electron-density gap for molecular transport with a reasonable energy barrier (11).The lattice of graphene can be engineered by postsynthetic etching to obtain attractive separation performance, for example, by using an electron (12) and ion (13) beam or by chemical etching techniques involving O₂ (14), O₂ plasma (15, 16), O₃ (17–19), or UV/O₃ (20). However, the postsynthetic lattice etching adds an additional and often complex processing step in the overall fabrication process. It is attractive to avoid this step from the point of view of membrane scale-up. This makes the bottom-up approach, capable of synthesizing a nanoporous graphene film in a single synthesis step, extremely desirable. For example, Ullmann coupling is a highly promising route that yields porous lattice with a precise pore structure (21); however, significant advances are needed to enlarge the ordered domains, which are currently only a few nanometers in size. Another promising strategy is to engineer the catalyst to selectively avoid graphene growth where pores are desired. For example, Park and coworkers deposited 2 to 10 nm tungsten islands in a Cu foil to locally shield the Cu surface during growth giving rise to a porous graphene with 20 to 50 nm pores and a pore density of ∼10¹⁰ cm⁻² (22).An attractive approach for the bottom-up synthesis of nanoporous graphene is to promote the incorporation of intrinsic vacancy defects in the graphene lattice during its crystallization. A proof of principle of this idea for molecular separation has been demonstrated by altering the chemical vapor deposition conditions of polycrystalline single-layer graphene (SLG) on a catalytic Cu foil (17, 18). Tuning the synthesis temperature (23), the precursor (methane, benzene) (24), and the roughness/orientation of the catalytic Cu foil (25) has been shown to yield intrinsic vacancy defects that could separate small molecules based on their size, for example H₂ from CH₄. However, the SLG’s true potential of ultrahigh molecular permeance could not be realized in these reports because the density of vacancy defects was low. To put this into perspective, the graphene lattice hosts 3.8 × 10¹⁵ atoms cm⁻², and the highest reported density of molecular-sieving vacancy defects is ∼5 × 10¹⁰ cm⁻² (24), whereas postsynthetic etching has been successfully used to incorporate defect density of 10¹² cm⁻² (16, 19, 26). Therefore, the development of a direct bottom-up method incorporating a high density of molecular-sized intrinsic vacancy defects in graphene would be highly attractive.A major source of intrinsic vacancy defects in polycrystalline graphene is the incomplete intergrowth of misaligned grains (27–34). Therefore, to increase the density of such defects, one needs to reduce the grain size. Also, to make the vacancies large enough for selective molecular translocation, one needs to increase the misalignment between the grains. To the best of our knowledge, growth conditions that promote small, misoriented grains incorporating a high density of molecular-sized vacancies in graphene have not been reported. We note that while there have been several reports on nanocrystalline graphene, none of them reported a porous lattice. For example, a helium leak test carried out on sealed nanocrystalline graphene film, synthesized via the quenching approach, verified the absence of He-permeable vacancy defects in such films (35). Nanocrystalline graphene films have also been synthesized by electron-radiation–induced cross-linking of aromatic self-assembled monolayers on Au (36), graphitization of polymeric precursor on Ge (37), diffusion of carbon through Ni grain boundaries (38), quenching of Pt foil in a carbon solution (35, 39), etc. However, molecular-scale vacancy defects were not observed.Herein, we report a graphene synthesis route based on the controlled precipitation and crystallization of carbon on Ni surface at a low temperature that limits the grain size in graphene to less than 5 nm and allows the realization of a high density (∼10¹² cm⁻²) of molecular-sieving intrinsic vacancy defects or nanopores by the bottom-up synthetic route. The nanocrystalline graphene is few layered (two to four layers) except near the nanopores where the grains taper into a single layer and eventually terminate leading to vacancies (Fig. 1A). This nanostructure, which we refer to as porous nanocrystalline graphene (PNG), is highly attractive for the membrane-based molecular separation because the layered domains increase the mechanical robustness of the film, and the atom-thick apertures allow the realization of high-permeance attributing to the single rate-limiting transition state at the center of the pore (40).Open in a separate windowFig. 1.The nanostructure of PNG film. (A) Schematic of PNG showing the nanopores that form when three or more nanocrystalline graphene grains with different orientations meet. (B) AC-HRTEM image of the PNG-1 synthesized by exposing a 25 μm thick Ni foil to the pyrolysis products of PS-b-P4VP and turanose (1:2 weight ratio) at 500 °C. The orange arrows point toward the nanopores, and the yellow squares indicate the areas used for computing the FFT images presented at the bottom of the panel. The scale bars in the FFT indicate 2 nm⁻¹, and the angles indicate the relative rotation of the graphene grains from an arbitrary reference point. (C) AC-HRTEM images of several nanopores. (Scale bar, 1 nm.) The PNG-1 samples were imaged directly after transferring to the TEM grid. No posttreatment or cleaning protocol was used before imaging.The presence of high-density intrinsic vacancy defects led to extremely high H₂ permeance (38,000 gas permeation units or GPU; 1 GPU = 3.35 × 10⁻¹⁰ mol m⁻² s⁻¹ Pa⁻¹). The pores were commensurate with the size of H₂ indicated by activated transport of H₂ and attractive H₂/CH₄, H₂/N₂ and CO₂/N₂ selectivities. The combination of permeance and selectivity is comparable to the state-of-the-art graphene membranes prepared by postsynthetic lattice etching (19, 41). Additionally, functionalization and masking methods previously demonstrated to improve the performance of postsynthetically etched graphene could be applied to PNG to fine-tune the application-specific performance. For example, oxygen functionalization of the pores increased H₂/CH₄ and H₂/N₂ selectivities by 150 and 130%, respectively. Masking PNG with CO₂-phillic polymers led to attractive carbon capture performance with CO₂ permeance of 5,700 GPU and a CO₂/N₂ separation factor of 31.     

Social isolation and chronic handling alter endocannabinoid signaling and behavioral reactivity to context in adult rats

Social deprivation in early life disrupts emotionality and attentional processes in humans. Rearing rats in isolation reproduces some of these abnormalities, which are attenuated by daily handling. However, the neurochemical mechanisms underlying these responses remain poorly understood. We hypothesized that post-weaning social isolation alters the endocannabinoid system, a neuromodulatory system that controls emotional responding. We characterized behavioral consequences of social isolation and evaluated whether handling would reverse social isolation-induced alterations in behavioral reactivity to context and the endocannabinoid system. At weaning, pups were single or group housed and concomitantly handled or not handled daily until adulthood. Rats were tested in emotionality- and attentional-sensitive behavioral assays (open field, elevated plus maze, startle and prepulse inhibition). Cannabinoid receptor densities and endocannabinoid levels were quantified in a separate group of rats. Social isolation negatively altered behavioral responding. Socially-isolated rats that were handled showed less deficits in the open field, elevated plus maze, and prepulse inhibition tests. Social isolation produced site-specific alterations (supraoptic nucleus, ventrolateral thalamus, rostral striatum) in cannabinoid receptor densities compared to group rearing. Handling altered the endocannabinoid system in neural circuitry controlling emotional expression. Handling altered endocannabinoid content (prefrontal and piriform cortices, nucleus accumbens) and cannabinoid receptor densities (lateral globus pallidus, cingulate and piriform cortices, hippocampus) in a region-specific manner. Some effects of social isolation on the endocannabinoid system were moderated by handling. Isolates were unresponsive to handling-induced increases in cannabinoid receptor densities (caudal striatum, anterior thalamus), but were sensitive to handling-induced changes in endocannabinoid content (piriform, prefrontal cortices), compared to group-reared rats. Our findings suggest alterations in the endocannabinoid system may contribute to the abnormal isolate phenotype. Handling modifies the endocannabinoid system and behavioral reactivity to context, but surmounts only some effects of social isolation. These data implicate a pivotal role for the endocannabinoid system in stress adaptation and emotionality-related disturbances.     

Myocardial Perfusion SPECT Imaging Radiomic Features and Machine Learning Algorithms for Cardiac Contractile Pattern Recognition

A U-shaped contraction pattern was shown to be associated with a better Cardiac resynchronization therapy (CRT) response. The main goal of this study is to automatically recognize left ventricular contractile patterns using machine learning algorithms trained on conventional quantitative features (ConQuaFea) and radiomic features extracted from Gated single-photon emission computed tomography myocardial perfusion imaging (GSPECT MPI). Among 98 patients with standard resting GSPECT MPI included in this study, 29 received CRT therapy and 69 did not (also had CRT inclusion criteria but did not receive treatment yet at the time of data collection, or refused treatment). A total of 69 non-CRT patients were employed for training, and the 29 were employed for testing. The models were built utilizing features from three distinct feature sets (ConQuaFea, radiomics, and ConQuaFea + radiomics (combined)), which were chosen using Recursive feature elimination (RFE) feature selection (FS), and then trained using seven different machine learning (ML) classifiers. In addition, CRT outcome prediction was assessed by different treatment inclusion criteria as the study’s final phase. The MLP classifier had the highest performance among ConQuaFea models (AUC, SEN, SPE = 0.80, 0.85, 0.76). RF achieved the best performance in terms of AUC, SEN, and SPE with values of 0.65, 0.62, and 0.68, respectively, among radiomic models. GB and RF approaches achieved the best AUC, SEN, and SPE values of 0.78, 0.92, and 0.63 and 0.74, 0.93, and 0.56, respectively, among the combined models. A promising outcome was obtained when using radiomic and ConQuaFea from GSPECT MPI to detect left ventricular contractile patterns by machine learning.

     

Effect of antioxidant therapy on blood pressure and NO synthase expression in hypertensive rats

Earlier studies have demonstrated evidence for increased reactive oxygen species, enhanced NO synthase (NOS) expression, and elevated NO production in spontaneously hypertensive rats (SHR). Given the negative-feedback regulation of NOS by NO, we hypothesized that enhanced NO inactivation by ROS may contribute to compensatory upregulation of NOS in SHR. The present study was designed to test this hypothesis. Eight-week-old male SHR and Wistar-Kyoto rats were treated for 3 weeks with either a placebo or the potent antioxidant, lazaroid (desmethyltirilazad, 10 mg. kg(-1). d(-1), by gastric gavage). Tail arterial blood pressure, urinary excretion of NO metabolites (ie, nitrate and nitrite), and immunodetectable NOS isotype proteins in the vascular, renal, cardiac, and cerebral tissues were measured. The placebo-treated SHR group showed a marked elevation of blood pressure and a significant upregulation of aorta, kidney, and cardiac tissue endothelial and inducible NOS (eNOS and iNOS, respectively) proteins and of brain and renal tissue neuronal NOS. Lazaroid therapy ameliorated hypertension and mitigated the upregulation of eNOS and iNOS in vascular, renal, and cardiac tissues but had limited effect on the expression of renal and brain neuronal NOS. In contrast, lazaroid therapy had no effect on blood pressure, urinary nitrate and nitrite excretion, or tissue NOS isotype expressions in the Wistar-Kyoto group. These findings support the role of oxidative stress in the genesis and/or maintenance of hypertension and compensatory upregulation of the expression of eNOS and iNOS in SHR.