Moxibustion attenuates neurogenic detrusor overactivity in spinal cord injury rats by inhibiting M2/ATP/P2X3 pathway.

PURPOSE: Activation of muscarinic receptors located in bladder sensory pathways is generally considered to be the primary contributor for driving the pathogenesis of neurogenic detrusor overactivity following spinal cord injury. The present study is undertaken to examine whether moxibustion improves neurogenic detrusor overactivity via modulating the abnormal muscarinic receptor pathway. MATERIALS AND METHODS: Female Sprague-Dawley rats were subjected to spinal cord injury with T9-10 spinal cord transection. Fourteen days later, animals were received moxibustion treatment for one week. Urodynamic parameters and pelvic afferents discharge were measured. Adenosine triphosphate (ATP) content in the voided cystometry fluid was determined. Expressions of M2, M3, and P2X3 receptors in the bladder mucosa were evaluated. RESULTS: Moxibustion treatment prevented the development of detrusor overactivity in spinal cord injury rats, with an increase in the intercontraction interval and micturition pressure threshold and a decrease in afferent activity during filling. The expression of M2 was markedly suppressed by moxibustion, accompanied by a reduction in the levels of ATP and P2X3. M2 receptor antagonist methoctramine hemihydrate had similar effects to moxibustion on bladder function and afferent activity, while the M2-preferential agonist oxotremorine methiodide abolished the beneficial effects of moxibustion. CONCLUSION: Moxibustion is a potential candidate for treating neurogenic bladder overactivity in a rat model of spinal cord injury, possibly through inhibiting the M2/ATP/P2X3 pathway.

Preclinical characterization of the JAK/STAT inhibitor SGI-1252 on skeletal muscle function, morphology, and satellite cell content.

BACKGROUND: Recent studies have highlighted the JAK/STAT signaling pathway in the regulation of muscle satellite cell behavior. Herein we report preclinical studies designed to characterize the effects of a novel JAK/STAT inhibitor on plantar flexor skeletal muscle function, morphology, and satellite cell content. METHODS: The compound, SGI-1252, was administered orally (400mg/kg) in a 10% dextrose solution to wild type mice (n = 6) 3 times per week for 8 weeks. A control group (n = 6) received only the dextrose solution. RESULTS: SGI-1252 was well tolerated, as animals displayed similar weight gain over the 8-week treatment period. Following treatment, fatigue in the gastrocnemius-soleus-plantaris complex was greater in the SGI-1252 mice during a 300 second tetanic contraction bout (p = 0.035), though both the rate of fatigue and maximal force production were similar. SGI-1252 treated mice had increased type II myofiber cross-sectional area (1434.8 ± 225.4 vs 1754.7 ± 138.5 µm2), along with an increase in wet muscle mass (125.45 ± 5.46 vs 139.6 ± 12.34 mg, p = 0.032) of the gastrocnemius relative to vehicle treated mice. SGI-1252 treatment reduced gastrocnemius STAT3 phosphorylation 53% (94.79 ± 45.9 vs 44.5 ± 6.1 MFI) and significantly increased the concentration of Pax7+ satellite cells (2589.2 ± 105.5 vs 2859.4 ± 177.5 SC/mm3) in the gastrocnemius. SGI-1252 treatment suppressed MyoD (p = 0.013) and Myogenin (p<0.0001) expression in human primary myoblasts, resulting in reduced myogenic differentiation (p = 0.039). CONCLUSIONS: Orally delivered SGI-1252 was well tolerated, attenuates skeletal muscle STAT3 activity, and increases satellite cell content in mouse gastrocnemius muscle, likely by inhibiting myogenic progression.

An upconversion nanoplatform for simultaneous photodynamic therapy and Pt chemotherapy to combat cisplatin resistance.

Platinum-based antineoplastic drugs are among the first-line chemotherapeutic agents against a variety of solid tumors, but toxic side-effects and drug resistance issues limit their clinical optimization. Novel strategies and platforms to conquer cisplatin resistance are highly desired. Herein, we assembled a multimodal nanoplatform utilizing 808 nm-excited and biocompatible core-shell-shell upconversion nanoparticles (UCNPs) [NaGdF4:Yb/Nd@NaGdF4:Yb/Er@NaGdF4] that were covalently loaded with not only photosensitizers (PSs), but also Pt(iv) prodrugs, which were rose bengal (RB) and c,c,t-[Pt(NH3)2Cl2(OCOCH2CH2NH2)2], respectively. The UCNPs had the capability to convert near infrared (NIR) light to visible light, which was further utilized by RB to generate singlet oxygen. At the same time, the nanoplatform delivered the Pt(iv) prodrug into cancer cells. Thus, this upconversion nanoplatform was able to carry out combined and simultaneous photodynamic therapy (PDT) and Pt chemotherapy. The nanoplatform was well characterized and the energy transfer efficiency was confirmed. Compared with free cisplatin or UCNPs loaded with RB only, our nanoplatform showed significantly improved cytotoxicity upon 808 nm irradiation in both cisplatin-sensitive and -resistant human ovarian cancer cells. A mechanistic study showed that the nanoparticles efficiently delivered the Pt(iv) prodrug into cancer cells, resulting in Pt-DNA damage, and that the nanoplatform generated cellular singlet oxygen to kill cancer cells. We, therefore, provide a comprehensive strategy to use UCNPs for combined Pt chemotherapy and PDT against cisplatin resistance, and our nanoplatform can also be used as a theranostic tool due to its NIR bioimaging capacity.

Astragaloside IV protects cardiomyocytes from anoxia/reoxygenation injury by upregulating the expression of Hes1 protein.

Astragaloside IV (ASI), a traditional Chinese medicine, is a main active ingredient of Astragalus membranaceus. Many clinical studies have found that ASI protects cardiomyocytes in cardiovascular diseases, but the underlying mechanisms remain obscure. The aim of this study was to investigate the molecular mechanisms responsible for the protective effects of ASI in cardiomyocytes from anoxia/reoxygenation (A/R) injury. According to the previous studies, we hypothesized that the cardioprotective effects of ASI against A/R injury might be associated with Notch1/Hes1 signaling pathway. In this study, neonatal rat primary cardiomyocytes were preconditioned with ASI prior to A/R injury. Our results showed that ASI effectively increased the cell viability, decreased the content of MDA, decreased the activities of CPK and LDH, increased the activities of GSH-Px and SOD, and reduced the reactive oxygen species (ROS) generation and the loss of mitochondrial membrane potential (Δψm). ASI inhibited the mitochondrial permeability transition pore (mPTP) opening and activation of caspase-3, and finally decreased the cell apoptosis in cardiomyocytes. Furthermore, ASI upregulated Hes1 protein expression. However, pretreatment with DAPT, a Notch1 inhibitor, effectively attenuated the cardioprotective effects of ASI against A/R injury, except MDA, SOD, GSH-Px, and the ROS generation. Taken together, we demonstrated that ASI could protect against A/R injury via the Notch1/Hes1 signaling pathway.

Antibacterial Diamines Targeting Bacterial Membranes.

Antibiotic resistance is a growing threat to human health exacerbated by a lack of new antibiotics. We now describe a series of substituted diamines that produce rapid bactericidal activity against both Gram-positive and Gram-negative bacteria, including methicillin-resistant Staphylococcus aureus and stationary-phase bacteria. These compounds reduce biofilm formation and promote biofilm dispersal in Pseudomonas aeruginosa. The most potent analogue, 3 (1,13-bis{[(2,2-diphenyl)-1-ethyl]thioureido}-4,10-diazatridecane), primarily acts by depolarization of the cytoplasmic membrane and permeabilization of the bacterial outer membrane. Transmission electron microscopy confirmed that 3 disrupts membrane integrity rapidly. Compound 3 is also synergistic with kanamycin, demonstrated by the checkerboard method and by time-kill kinetic experiments. In human cell toxicity assays, 3 showed limited adverse effects against the HEK293T human kidney embryonic cells and A549 human adenocarcinoma cells. In addition, 3 produced no adverse effects on Caenorhabditis elegans development, survival, and reproduction. Collectively, diamines related to 3 represent a new class of broad-spectrum antibacterials against drug-resistant pathogens.

Simultaneous biosynthesis of putrebactin, avaroferrin and bisucaberin by Shewanella putrefaciens and characterisation of complexes with iron(III), molybdenum(VI) or chromium(V).

Cultures of Shewanella putrefaciens grown in medium containing 10mM 1,4-diamino-2-butanone (DBO) as an inhibitor of ornithine decarboxylase and 10mM 1,5-diaminopentane (cadaverine) showed the simultaneous biosynthesis of the macrocyclic dihydroxamic acids: putrebactin (pbH2), avaroferrin (avH2) and bisucaberin (bsH2). The level of DBO did not completely repress the production of endogenous 1,4-diaminobutane (putrescine) as the native diamine substrate of pbH2. The relative concentration of pbH2:avH2:bsH2 was 1:2:1, which correlated with the substrate selection of putrescine:cadaverine in a ratio of 1:1. The macrocycles were characterised using LC-MS as free ligands and as 1:1 complexes with Fe(III) of the form [Fe(pb)]+, [Fe(av)]+ or [Fe(bs)]+, with labile ancillary ligands in six-coordinate complexes displaced during ESI-MS acquisition; or with Mo(VI) of the form [Mo(O)2(pb)], [Mo(O)2(av)] or [Mo(O)2(bs)]. Chromium(V) complexes of the form [CrO(pb)]+ were detected from solutions of Cr(VI) and pbH2 in DMF using X-band EPR spectroscopy. Supplementation of S. putrefaciens medium with DBO and 1,3-diaminopropane, 1,6-diaminohexane or 1,4-diamino-2(Z)-butene (Z-DBE) resulted only in the biosynthesis of pbH2. The work has identified a native system for the simultaneous biosynthesis of a suite of three macrocyclic dihydroxamic acid siderophores and highlights both the utility of precursor-directed biosynthesis for expanding the structural diversity of siderophores, and the breadth of their coordination chemistry.

Effects of Dangkwisoo­san, a traditional herbal medicine for treating pain and blood stagnation, on the pacemaker activities of cultured interstitial cells of Cajal.

The interstitial cells of Cajal (ICCs) are the pacemaker cells in the gastrointestinal (GI) tract. In the present study, the effects of Dangkwisoo­san (DS) on pacemaker potentials in cultured ICCs from the small intestine of the mouse were investigated. The whole­cell patch­clamp configuration was used to record pacemaker potentials from cultured ICCs and the increase in intracellular Ca2+ concentration ([Ca2+i) was analyzed in cultured ICCs using fura­2­acetoxymethyl ester. The generation of pacemaker potentials in the ICCs was observed. DS produced pacemaker depolarizations in a concentration dependent manner in current clamp mode. The 4­diphenylacetoxy­N­methyl­piperidine methiodide muscarinic M3 receptor antagonist inhibited DS­induced pacemaker depolarizations, whereas methoctramine, a muscarinic M2 receptor antagonist, did not. When guanosine 5'­[ß­thio] diphosphate (GDP­ß­S; 1 mM) was in the pipette solution, DS marginally induced pacemaker depolarizations, whereas low Na+ solution externally eliminated the generation of pacemaker potentials and inhibited the DS­induced pacemaker depolarizations. Additionally, the nonselective cation channel blocker, flufenamic acid, inhibited the DS­induced pacemaker depolarizations. Pretreatment with Ca2+­free solution and thapsigargin, a Ca2+­ATPase inhibitor in the endoplasmic reticulum, also eliminated the generation of pacemaker currents and suppressed the DS­induced pacemaker depolarizations. In addition, [Ca2+]i analysis revealed that DS increased [Ca2+]i. These results suggested that DS modulates pacemaker potentials through muscarinic M3 receptor activation in ICCs by G protein­dependent external and internal Ca2+ regulation and external Na+. Therefore, DS were observed to affect intestinal motility through ICCs.

Blocking M2 muscarinic receptor signaling inhibits tumor growth and reverses epithelial-mesenchymal transition (EMT) in non-small cell lung cancer (NSCLC).

Lung cancers express non-neuronal, cholinergic autoparacrine loop, which facilitates tumor growth. Interruption of M3 muscarinic cholinergic signaling has been reported to inhibit small cell lung cancer (SCLC) growth. The purpose of this study is to investigate if blocking autoparacrine muscarinic cholinergic signaling could inhibit non-small cell lung cancer (NSCLC) growth and possible underlying mechanisms. Our results showed that PC9 and A549 cells expressed all 5 subtypes of muscarinic receptor (mAChR) and blocking M2 mAChR (M2R) signaling using selective antagonist methoctramine or short hairpin RNA (shRNA) inhibited tumor cell proliferation in vitro and in vivo. Consistent with AChR agonists stimulating p44/42 MAPK (Erk1/2) and Akt phosphorylation, blocking M2R signaling decreased MAPK and Akt phosphorylation, indicating that non-neuronal ACh functions as an autoparacrine growth factor signaling in part through activation of M2R and downstream MAPK and Akt pathways. Importantly, further studies revealed that blocking M2R signaling also reversed epithelial-mesenchymal transition (EMT) in vitro and in vivo, indicating that non-neuronal ACh promotes EMT partially through activation of M2R. These findings demonstrate that M2R plays a role in the growth and progression of NSCLC and suggest M2R antagonists may be an efficacious adjuvant therapy for NSCLC.

Inhibition of protein synthesis and malaria parasite development by drug targeting of methionyl-tRNA synthetases.

Aminoacyl-tRNA synthetases (aaRSs) are housekeeping enzymes that couple cognate tRNAs with amino acids to transmit genomic information for protein translation. The Plasmodium falciparum nuclear genome encodes two P. falciparum methionyl-tRNA synthetases (PfMRS), termed PfMRS(cyt) and PfMRS(api). Phylogenetic analyses revealed that the two proteins are of primitive origin and are related to heterokonts (PfMRS(cyt)) or proteobacteria/primitive bacteria (PfMRS(api)). We show that PfMRS(cyt) localizes in parasite cytoplasm, while PfMRS(api) localizes to apicoplasts in asexual stages of malaria parasites. Two known bacterial MRS inhibitors, REP3123 and REP8839, hampered Plasmodium growth very effectively in the early and late stages of parasite development. Small-molecule drug-like libraries were screened against modeled PfMRS structures, and several "hit" compounds showed significant effects on parasite growth. We then tested the effects of the hit compounds on protein translation by labeling nascent proteins with (35)S-labeled cysteine and methionine. Three of the tested compounds reduced protein synthesis and also blocked parasite growth progression from the ring stage to the trophozoite stage. Drug docking studies suggested distinct modes of binding for the three compounds, compared with the enzyme product methionyl adenylate. Therefore, this study provides new targets (PfMRSs) and hit compounds that can be explored for development as antimalarial drugs.

Discovery of novel AKT inhibitors with enhanced anti-tumor effects in combination with the MEK inhibitor.

Tumor cells upregulate many cell signaling pathways, with AKT being one of the key kinases to be activated in a variety of malignancies. GSK2110183 and GSK2141795 are orally bioavailable, potent inhibitors of the AKT kinases that have progressed to human clinical studies. Both compounds are selective, ATP-competitive inhibitors of AKT 1, 2 and 3. Cells treated with either compound show decreased phosphorylation of several substrates downstream of AKT. Both compounds have desirable pharmaceutical properties and daily oral dosing results in a sustained inhibition of AKT activity as well as inhibition of tumor growth in several mouse tumor models of various histologic origins. Improved kinase selectivity was associated with reduced effects on glucose homeostasis as compared to previously reported ATP-competitive AKT kinase inhibitors. In a diverse cell line proliferation screen, AKT inhibitors showed increased potency in cell lines with an activated AKT pathway (via PI3K/PTEN mutation or loss) while cell lines with activating mutations in the MAPK pathway (KRAS/BRAF) were less sensitive to AKT inhibition. Further investigation in mouse models of KRAS driven pancreatic cancer confirmed that combining the AKT inhibitor, GSK2141795 with a MEK inhibitor (GSK2110212; trametinib) resulted in an enhanced anti-tumor effect accompanied with greater reduction in phospho-S6 levels. Taken together these results support clinical evaluation of the AKT inhibitors in cancer, especially in combination with MEK inhibitor.

Acupuncture at heterotopic acupoints enhances jejunal motility in constipated and diarrheic rats.

AIM: To investigate the effect and mechanism of acupuncture at heterotopic acupoints on jejunal motility, particularly in pathological conditions. METHODS: Jejunal motility was assessed using a manometric balloon placed in the jejunum approximately 18-20 cm downstream from the pylorus and filled with approximately 0.1 mL warm water in anesthetized normal rats or rats with diarrhea or constipation. The heterotopic acupoints including LI11 (Quchi), ST37 (Shangjuxu), BL25 (Dachangshu), and the homotopic acupoint ST25 (Tianshu), and were stimulated for 60 s by rotating acupuncture needles right and left at a frequency of 2 Hz. To determine the type of afferent fibers mediating the regulation of jejunal motility by manual acupuncture, the ipsilateral sciatic A or C fibers of ST37 were inactivated by local application of the A-fiber selective demyelination agent cobra venom or the C fiber blocker capsaicin. Methoctramine, a selective M2 receptor antagonist, was injected intravenously to identify a specific role for M2 receptors in mediating the effect of acupuncture on jejunal motility. RESULTS: Acupuncture at heterotopic acupoints, such as LI11 and ST37, increased jejunal motility not only in normal rats, but also in rats with constipation or diarrhea. In normal rats, manual acupuncture at LI11 or ST37 enhanced jejunal pressure from 7.34 ± 0.19 cmH2O to 7.93 ± 0.20 cmH2O, an increase of 9.05% ± 0.82% (P < 0.05), and from 6.95 ± 0.14 cmH2O to 8.97 ± 0.22 cmH2O, a significant increase of 27.44% ± 1.96% (P < 0.01), respectively. In constipated rats, manual acupuncture at LI11 or ST37 increased intrajejunal pressure from 8.17 ± 0.31 cmH2O to 9.86 ± 0.36 cmH2O, an increase of 20.69% ± 2.10% (P < 0.05), and from 8.82 ± 0.28 cmH2O to 10.83 ± 0.28 cmH2O, an increase of 22.81% ± 1.46% (P < 0.05), respectively. In rats with diarrhea, MA at LI11 or ST37 increased intrajejunal pressure from 11.95 ± 0.35 cmH2O to 13.96 ± 0.39 cmH2O, an increase of 16.82% ± 2.35% (P < 0.05), and tended to increase intrajejunal pressure (from 12.42 ± 0.38 cmH2O to 13.05 ± 0.38 cmH2O, an increase of 5.07% ± 1.08%, P > 0.05), respectively. In contrast, acupuncture ST25, a homotopic acupoint, decreased not only intrajejunal pressure, but also significantly decreased frequency in normal rats and rats with constipation or diarrhea. Following demyelination of Aδ fibers, acupuncture at ST37 again augmented intrajejunal pressure to 121.48% ± 3.06% of baseline. Following capsaicin application for 24 h, acupuncture at ipsilateral ST37 increased intrajejunal pressure significantly to 106.63% ± 1.26% of basal levels when compared to measurements prior to capsaicin treatment (P < 0.05). Acupuncture at LI11, ST37, or BL25 significantly rescued methoctramine-mediated inhibition of jejunal motility amplitude from 42.83% ± 1.65% to 53.43% ± 1.95% of baseline (P < 0.05), from 45.15% ± 2.22% to 70.51% ± 2.34% of baseline (P < 0.01), and from 38.03% ± 2.34% to 70.12% ± 2.22% of baseline (P < 0.01), respectively. CONCLUSION: Acupuncture at heterotopic acupoints increases the amplitude of jejunal motility in rats. C fibers and M2 receptors predominantly and partially mediate the regulation of jejunal motility by acupuncture, respectively.

Antiviral stilbene 1,2-diamines prevent initiation of hepatitis C virus RNA replication at the outset of infection.

The recent development of a cell culture model of hepatitis C virus (HCV) infection based on the JFH-1 molecular clone has enabled discovery of new antiviral agents. Using a cell-based colorimetric screening assay to interrogate a 1,200-compound chemical library for anti-HCV activity, we identified a family of 1,2-diamines derived from trans-stilbene oxide that prevent HCV infection at nontoxic, low micromolar concentrations in cell culture. Structure-activity relationship analysis of ~ 300 derivatives synthesized using click chemistry yielded compounds with greatly enhanced low nanomolar potency and a > 1,000:1 therapeutic ratio. Using surrogate models of HCV infection, we showed that the compounds selectively block the initiation of replication of incoming HCV RNA but have no impact on viral entry, primary translation, or ongoing HCV RNA replication, nor do they suppress persistent HCV infection. Selection of an escape variant revealed that NS5A is directly or indirectly targeted by this compound. In summary, we have identified a family of HCV inhibitors that target a critical step in the establishment of HCV infection in which NS5A translated de novo from an incoming genomic HCV RNA template is required to initiate the replication of this important human pathogen.

9'-Epi-3ß,3'ß-dimethylxestospongin C, a new macrocyclic diamine alkaloid from the Hainan sponge Neopetrosia exigua.

A new BIS-1-oxaquinolizidine alkaloid, 9'- EPI-3 ß,3' ß-dimethylxestospongin C (2), and three known related analogues have been isolated from the Hainan sponge Neopetrosia exigua.

Spinal cholinergic mechanism of the relieving effects of electroacupuncture on cold and warm allodynia in a rat model of neuropathic pain.

This study was performed to determine whether spinal cholinergic systems mediate the relieving effects of electroacupuncture (EA) on cold and warm allodynia in a rat model of neuropathic pain. For neuropathic surgery, the right superior caudal trunk was resected at the level between the S1 and S2 spinal nerves innervating the tail. Two weeks after the injury, the intrathecal (i.t.) catheter was implanted. Five days after the catheterization, the rats were injected with atropine (non-selective muscarinic antagonist, 30 microg), mecamylamine (non-selective nicotinic antagonist, 50 microg), pirenzepine (M(1) muscarinic antagonist, 10 microg), methoctramine (M(2) antagonist, 10 microg) or 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) (M(3) antagonist, 10 microg). Ten minutes after the injection, EA was applied to the ST36 acupoint for 30 min. The cold and warm allodynia were assessed by the tail immersion test [i.e., immersing the tail in cold (4 degrees C) or warm (40 degrees C) water and measuring the latency of an abrupt tail movement] before and after the treatments. The i.t. atropine, but not mecamylamine, blocked the relieving effects of EA on cold and warm allodynia. Furthermore, i.t. pirenzepine attenuated the antiallodynic effects of EA, whereas methoctramine and 4-DAMP did not. These results suggest that spinal muscarinic receptors, especially M(1) subtype, mediate the EA-induced antiallodynia in neuropathic rats.

Refractoriness of the sheep superior vena cava myocardial sleeve.

The cardiomyocytes in the superior vena cava (SVC) myocardial sleeve have distinct action potentials and ionic current profiles, but the refractoriness of these cells has not been reported. Using standard intracellular microelectrode techniques, we demonstrated in sheep that the effective refractory period (ERP) of the cardiomyocytes in the SVC (114.7 +/- 6.5 ms) is shorter than that in the inferior vena cava (IVC) (166.7 +/- 6.2 ms), right atrial free wall (RAFW) (201.0 +/- 6.0 ms) and right atrial appendage (RAA) (203.1 +/- 5.8 ms) (P < 0.05). The right atrial cardiomyocyte ERP was heterogeneously shortened by acetylcholine, a muscarinic type 2 receptor (M(2)R) agonist. After perfusion with 15 microM acetylcholine, the shortest ERP occurred in the SVC (the ERP in the SVC, IVC, RAFW and RAA was 53.6 +/- 2.7, 98.9 +/- 2.2, 121.8 +/- 6.0 and 109.7 +/- 5.1 ms, respectively; P < 0.05). Carbachol (1 microM), another M(2)R agonist, produced a similar effect as acetylcholine. Furthermore, we used methoctramine, a M(2)R blocker, 4-DAMP, a muscarinic type 3 receptor (M(3)R) blocker, and tropicamide, a muscarinic type 4 receptor (M(4)R) blocker to inhibit the acetylcholine-induced ERP shortening of SVC cardiomyocytes, and found that the 50% inhibitory concentration for methoctramine, 4-DAMP and tropicamide was 5.91, 45.72 and 80.34 nM, respectively. Therefore, we conclude that the sheep SVC myocardial sleeve is a unique electrophysiological region of the right atrium with the shortest ERP both under physiological condition and under cholinergic agonist stimulation. M(2)R might play a major role in the response of the SVC myocardial sleeve to parasympathetic nerve tone. The association between the distinct refractoriness in SVC and atrial fibrillation originating from the region deserves further investigation.

Recent advances in the preclinical evaluation of the topical antibacterial agent REP8839.

REP8839 is a synthetic fluorovinylthiophene-containing diaryldiamine that inhibits bacterial methionyl tRNA synthetase (MetRS) and is a new chemical entity that represents a novel pharmacological class. The compound has potent in vitro antibacterial activity against many clinically important Gram-positive bacteria including the major skin pathogens Staphylococcus aureus and Streptococcus pyogenes. In light of the emergence of methicillin-resistant S. aureus in the community and increasing resistance to mupirocin, REP8839 is being evaluated as a topical agent for the treatment of superficial skin infections. REP8839 was active against resistant phenotypes of S. aureus and can be formulated at high concentrations to minimize the development of resistance. A formulation of REP8839 has demonstrated efficacy in a porcine partial thickness wound infection model against mupirocin-resistant S. aureus.

Antagonism of nucleus accumbens M(2) muscarinic receptors disrupts operant responding for sucrose under a progressive ratio reinforcement schedule.

Diverse cholinergic signaling mechanisms regulate the excitability of striatal principal neurons and modulate striatal-dependent behavior. These effects are mediated, in part, by action at muscarinic receptors (mAChR), subtypes of which exhibit distinct patterns of expression across striatal neuronal populations. Non-selective mAChR blockade within the nucleus accumbens (NAc) has been shown to disrupt operant responding for food and to inhibit food consumption. However, the specific receptor subtypes mediating these effects are not known. Thus, we evaluated effects of intra-NAc infusions of pirenzepine and methoctramine, mAChR antagonisits with distinct binding affinity profiles, on operant responding for sucrose reward under a progressive ratio (PR) reinforcement schedule. Moderate to high doses of methoctramine disrupted operant responding and reduced behavioral breakpoint. In contrast, pirenzepine failed to impact operant performance at any dose tested. Methoctramine failed to affect latencies to complete appetitive-consummatory response sequences or to impact measures of acoustic startle, suggesting that its' disruptive effects on operant behavior were not consequent to gross motor impairment. Since methoctramine has a greater affinity for M(2) receptors compared to pirenzepine, which has a greater relative affinity for M(1) and M(3) receptors, these findings suggest that M(2) mAChRs within the NAc regulate behavioral processes underling the acquisition of reward.

Muscarinic M2 receptor is active on pancreatic islets from hypothalamic obese rat.

Hypothalamic obese rats, obtained by neonatal treatment with monosodium L-glutamate (MSG), are hyperinsulinemic, and secrete more insulin than lean ones do when stimulated by glucose, while acetylcholine insulinotropic effect decreases. The effect of acetylcholine on glucose-induced insulin secretion is attributed to muscarinic receptors of pancreatic beta cells, mainly to M(3) subtype. However, it has been observed that activation of M(2) or M(4) subtypes causes inhibition of glucose-induced insulin secretion in insulin secreting cell line. Insulin secretion was measured, stimulated by glucose in the presence of acetylcholine plus methoctramine, a muscarinic M(2) antagonist, on pancreatic islets isolated from MSG-obese and lean rats to investigate whether impairment of acetylcholine insulinotropic effect on pancreatic islets from MSG-obese rats has any relationship with muscarinic M(2) receptor function in beta cells. Insulin secretion stimulated by 8.3 mM glucose was higher in islets from obese rats than from lean ones. Insulinotropic effect of acetylcholine was reported in islets of both animals, albeit less than in obese ones. Blockage of muscarinic M(2) receptor, using methoctramine at 1; 5 and 10 microM, increased acetylcholine secretory response in islets of obese rats, while no effect has been observed in lean ones. Results demonstrate that muscarinic M(2) receptors are functioning in pancreatic islets of MSG-obese rats. The inhibitory action of muscarinic M(2) receptor may be a mechanism by which acetylcholine discloses weak insulinotropic effect in MSG-obese rats.

Syntheses and biological evaluation of alkanediamines as antioxidant and hypolipidemic agents.

A new series of compounds belonging to N,N'- [bis (1-aryl-6-hydroxy-hex-2-ene-1-one-3-yl)-1,n-alkanediamines (2-5a-f) have been synthesized and evaluated for antioxidant and hypolipidemic activities. Amongst all the synthesized compounds, seven compounds namely 2c, 2e, 4c, 5b, 5c, 5e and 5f exhibit potent antioxidant activity. These compounds have also been evaluated for hypolipidemic activity.

How to improve instrument disinfection by ultrasound.

Ultrasound technologies have a wide range of hospital and dental applications which include cleaning and disinfection of surgical and dental instruments. We measured the germicidal efficacy of sonication, with or without chemical disinfectants, in an ultrasonic bath delivering a frequency of 35 kHz and an intensity of 0.66 W/cm2. Cultures of Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans were exposed to ultrasound and to an amine-based disinfectant in non-bactericidal concentrations. Ultrasonication for 60 min alone did not cause a significant killing of the bacteria and yeast. However, we were able to show that sonication can act as a powerful synergistic agent to increase the cidal efficacy of the disinfectant against S. aureus and P. aeruginosa. C. albicans was more resistant to the combination of ultrasound and chemical disinfection. The key role in the action of ultrasound in cleaning of instruments and perhaps in enhanced disinfection is played by cavitation phenomena. The distribution of cavitations in an ultrasonic bath is not homogenous. We found a similar synergistic effect of ultrasound and disinfectant in positions with low cavitation. The synergistic effect was not reduced inside rubber tubes. Before ultrasound can be accepted as an integral part of the cleaning and disinfection process of medical instruments, the influence of intensity and frequency of sonication and the effects of cavitation must be clarified.