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Introduction For patients on renal replacement therapy (RRT), "travel" and "independence" are rated as 2 of the top 5 factors that inform their choice of treatment modality. While home dialysis modalities offer patients a high degree of independence, the most common RRT in the United States is in-center hemodialysis (IHD). The limits imposed by IHD treatment can present a variety of challenges for patients who wish to travel. This study explored how IHD patients managed their travel and the role of dialysis social workers in executing travel arrangements for patients. Methods We performed a qualitative descriptive investigation using semi-structured interviews with adults receiving IHD (n = 16) and renal social workers (n = 8) from Iowa, Minnesota, North Dakota, South Dakota, and Wisconsin. Data were analyzed using a constant comparative method. Findings Three themes emerged from the interviews: travel process, travel-related barriers, and travel-related facilitators. The travel process entailed transient dialysis unit challenges and the need for multiple preparations and precautions. Barriers included comorbidities and not having a relationship with transient dialysis unit staff. Facilitators focused on the importance of travel and staff professionalism at transient dialysis units. Overall, there was lack of uniform protocols to guide the travel process at the patient and the dialysis unit levels. Discussion This study identified multiple perspectives regarding travel arrangements in chronic IHD patients. There is limited research on travel issues for IHD patients and this investigation is among the first to articulate barriers and facilitators associated with travel from the perspective of patients and social workers. Supporting travel for IHD patients can increase their sense of autonomy and provide opportunities to improve their quality of life.

In recent years, cannabinoid type 2 receptors (CB2R) have emerged as promising therapeutic targets in a wide variety of diseases. Selective ligands of CB2R are devoid of the psychoactive effects typically observed for CB1R ligands. Based on our recent studies on a class of pyridazinone 4-carboxamides, further structural modifications of the pyridazinone core were made to better investigate the structure–activity relationships for this promising scaffold with the aim to develop potent CB2R ligands. In binding assays, two of the new synthesized compounds [6-(3,4-dichlorophenyl)-2-(4-fluorobenzyl)-cis-N-(4-methylcyclohexyl)-3-oxo-2,3-dihydropyridazine-4-carboxamide (2) and 6-(4-chloro-3-methylphenyl)-cis-N-(4-methylcyclohexyl)-3-oxo-2-pentyl-2,3-dihydropyridazine-4-carboxamide (22)] showed high CB2R affinity, with Ki values of 2.1 and 1.6 nm, respectively. In addition, functional assays of these compounds and other new active related derivatives revealed their pharmacological profiles as CB2R inverse agonists. Compound 22 displayed the highest CB2R selectivity and potency, presenting a favorable in silico pharmacokinetic profile. Furthermore, a molecular modeling study revealed how 22 produces inverse agonism through blocking the movement of the toggle-switch residue, W6.48.

Background & aims Anticoagulants are commonly indicated in cirrhotic patients due to high rate of (pro)thrombotic conditions. Low molecular weight heparin (LMWH) is safe in patients with esophageal varices. However, the safety of LMWH is unknown in patients undergoing prophylactic endoscopic variceal ligation (EVL). To define the 4-week risk of bleeding and death after prophylactic EVL in cirrhotic patients continuously treated with LMWH. Methods All EVLs performed at a tertiary Italian Center from 2009 to 2016 were retrospectively reviewed. Patients treated with LMWH were classified as on-LMWH; the remaining as no-LMWH. Endoscopic characteristics at first and index EVL (that preceding an endoscopy either showing a bleeding episode or the absence of further treatable varices) and clinical events within 4 weeks from the procedures were recorded. Results and conclusions Five hundred fifty-three EVLs were performed in 265 patients (in 215 as a primary prophylaxis): 169 EVLs in 80 on-LMWH and 384 in 185 no-LMWH (4.9 ± 1.1 vs 4.8 ± 1.0 bands/session, respectively; P = .796). Six patients bled (2.2%) without between-groups difference (3.8% on-LMWH vs 1.6% no-LMWH, Log-rank P = .291). Large varices with red marks (100% vs 51.4%, P = .032), number of bands (5.6 ± 0.5 vs 4.6 ± 1.2, P = .004), underlying portal vein thrombosis (66.7% vs 23.6%, P = .033), and creatinine (2.2 ± 2.7 vs 1.0 ± 0.8 mg/dL, P = .001) at index EVL were significantly different between bleeders and non-bleeders. Six patients died within 4-week from index EVL, without between-groups difference (2.5% on-LMWH vs 2.2% no-LMWH, Log-rank P = .863). LMWH does not increase the risk of post-procedural bleeding and does not affect survival of cirrhotic patients undergoing prophylactic EVL.

The A3 adenosine receptor (A3 AR) subtype is a novel, promising therapeutic target for inflammatory diseases, such as rheumatoid arthritis (RA) and psoriasis, as well as liver cancer. A3 AR is coupled to inhibition of adenylyl cyclase and regulation of mitogen-activated protein kinase (MAPK) pathways, leading to modulation of transcription. Furthermore, A3 AR affects functions of almost all immune cells and the proliferation of cancer cells. Numerous A3 AR agonists, partial agonists, antagonists, and allosteric modulators have been reported, and their structure-activity relationships (SARs) have been studied culminating in the development of potent and selective molecules with drug-like characteristics. The efficacy of nucleoside agonists may be suppressed to produce antagonists, by structural modification of the ribose moiety. Diverse classes of heterocycles have been discovered as selective A3 AR blockers, although with large species differences. Thus, as a result of intense basic research efforts, the outlook for development of A3 AR modulators for human therapeutics is encouraging. Two prototypical selective agonists, N6-(3-Iodobenzyl)adenosine-5'-N-methyluronamide (IB-MECA; CF101) and 2-chloro-N6-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (Cl-IB-MECA; CF102), have progressed to advanced clinical trials. They were found safe and well tolerated in all preclinical and human clinical studies and showed promising results, particularly in psoriasis and RA, where the A3 AR is both a promising therapeutic target and a biologically predictive marker, suggesting a personalized medicine approach. Targeting the A3 AR may pave the way for safe and efficacious treatments for patient populations affected by inflammatory diseases, cancer, and other conditions.

Adenosine is an endogenous ubiquitous purine nucleoside, which is increased by hypoxia, ischaemia and tissue damage and mediates a number of physiopathological effects by interacting with four GPCRs, identified as A1 , A2A , A2B and A3 . Physiological and acutely increased adenosine is mostly associated with beneficial effects that include vasodilatation and a decrease in inflammation. In contrast, chronic overproduction of adenosine occurs in important pathological states, where long-lasting increases in the nucleoside levels are responsible for the bad side of adenosine associated with chronic inflammation, fibrosis and organ damage. In this review, we describe and critically discuss the pathological overproduction of adenosine and analyse when, where and how adenosine exerts its detrimental effects throughout the body.

Transient receptor potential vanilloid 1 (TRPV1) is an ion channel expressed on sensory neurons triggering an influx of cations. TRPV1 receptors function as homotetramers responsive to heat, proinflammatory substances, lipoxygenase products, resiniferatoxin, endocannabinoids, protons, and peptide toxins. Its phosphorylation increases sensitivity to both chemical and thermal stimuli, while desensitization involves a calcium-dependent mechanism resulting in receptor dephosphorylation. TRPV1 functions as a sensor of noxious stimuli and may represent a target to avoid pain and injury. TRPV1 activation has been associated to chronic inflammatory pain and peripheral neuropathy. Its expression is also detected in nonneuronal areas such as bladder, lungs, and cochlea where TRPV1 activation is responsible for pathology development of cystitis, asthma, and hearing loss. This review offers a comprehensive overview about TRPV1 receptor in the pathophysiology of chronic pain, epilepsy, cough, bladder disorders, diabetes, obesity, and hearing loss, highlighting how drug development targeting this channel could have a clinical therapeutic potential. Furthermore, it summarizes the advances of medicinal chemistry research leading to the identification of highly selective TRPV1 antagonists and their analysis of structure-activity relationships (SARs) focusing on new strategies to target this channel.

Granulocyte monocyte apheresis (GMA) is a non-pharmacological treatment for inflammatory bowel disease. In our study, we tested a novel GMA adsorber device in terms of clinical efficacy and safety in patients' non-response to pharmacological therapy. Secondary outcomes were the evaluation of adsorber's technical performance, the reduction of inflammatory markers and the improvement of patients' life quality. The prospective study included 18 patients enrolled from 2011 to 2012 with a monitoring of 48 weeks. All patients with Crohn's disease achieved a clinical remission after GMA treatments, sustained until the end of follow up, while 80% of ulcerative colitis patients obtained a clinical benefit, maintained after 48 weeks of monitoring. Leukocytes, neutrophils, monocytes and platelets, compared to erythrocytes and lymphocytes, were effectively removed from peripheral blood. There was no statistically significant result about serological markers of inflammation. A consistent improvement of the patients' quality of life was observed up to the end of follow up. No significant side-effects were recorded. Our study underlines the efficacy and the safety of this novel GMA adsorber device; a prospective randomized clinical trial with adequate sample size should be performed.

In the present study, the effect of low-frequency, low-energy pulsed electromagnetic fields (PEMFs) has been investigated by using different cell lines derived from neuron-like cells and microglial cells. In particular, the primary aim was to evaluate the effect of PEMF exposure in inflammation- and hypoxia-induced injury in two different neuronal cell models, the human neuroblastoma-derived SH-SY5Y cells and rat pheochromocytoma PC12 cells and in N9 microglial cells. In neuron-like cells, live/dead and apoptosis assays were performed in hypoxia conditions from 2 to 48 h. Interestingly, PEMF exposure counteracted hypoxia damage significantly reducing cell death and apoptosis. In the same cell lines, PEMFs inhibited the activation of the hypoxia-inducible factor 1α (HIF-1α), the master transcriptional regulator of cellular response to hypoxia. The effect of PEMF exposure on reactive oxygen species (ROS) production in both neuron-like and microglial cells was investigated considering their key role in ischemic injury. PEMFs significantly decreased hypoxia-induced ROS generation in PC12, SH-SY5Y, and N9 cells after 24 or 48 h of incubation. Moreover, PEMFs were able to reduce some of the most well-known pro-inflammatory cytokines such as tumor necrosis factor–α (TNF-α), interleukin (IL)-1β, IL-6, and IL-8 release in N9 microglial cells stimulated with different concentrations of LPS for 24 or 48 h of incubation time. These results show a protective effect of PEMFs on hypoxia damage in neuron-like cells and an anti-inflammatory effect in microglial cells suggesting that PEMFs could represent a potential therapeutic approach in cerebral ischemic conditions. J. Cell. Physiol. 232: 1200–1208, 2017. © 2016 Wiley Periodicals, Inc.

Pseudomonas aeruginosa produces increased levels of alginate in response to oxygen-deprived conditions. The regulatory pathway(s) that links oxygen limitation to increased synthesis of alginate has remained elusive. In the present study, using immunofluorescence microscopy, we show that anaerobiosis-induced alginate production by planktonic PAO1 requires the diguanylate cyclase (DGC) SadC, previously identified as a regulator of surface-associated lifestyles. Furthermore, we found that the gene products of PA4330 and PA4331, located in a predicted operon with sadC, have a major impact on alginate production: deletion of PA4330 (odaA, for oxygen-dependent alginate synthesis activator) caused an alginate production defect under anaerobic conditions, whereas a PA4331 (odaI, for oxygen-dependent alginate synthesis inhibitor) deletion mutant produced alginate also in the presence of oxygen, which would normally inhibit alginate synthesis. Based on their sequence, OdaA and OdaI have predicted hydratase and dioxygenase reductase activities, respectively. Enzymatic assays using purified protein showed that unlike OdaA, which did not significantly affect DGC activity of SadC, OdaI inhibited c-di-GMP production by SadC. Our data indicate that SadC, OdaA and OdaI are components of a novel response pathway of P. aeruginosa that regulates alginate synthesis in an oxygen-dependent manner.

Microglia are central nervous system (CNS)-resident immune cells, that play a crucial role in neuroinflammation. Hypoxia-inducible factor-1 (HIF-1), the main transcription factor of hypoxia-inducible genes, is also involved in the immune response, being regulated in normoxia by inflammatory mediators. Adenosine is an ubiquitous nucleoside that has an influence on many immune properties of microglia through interaction with four receptor subtypes. The aim of this study was to investigate whether adenosine may affect microglia functions by acting on HIF-1α modulation. Primary murine microglia were activated with lipopolysaccharide (LPS) with or without adenosine, adenosine receptor agonists and antagonists and HIF-1α accumulation and downstream genes regulation were determined. Adenosine increased LPS-induced HIF-1α accumulation leading to an increase in HIF-1α target genes involved in cell metabolism [glucose transporter-1 (GLUT-1)] and pathogens killing [inducible nitric-oxide synthase (iNOS)] but did not induce HIF-1α dependent genes related to angiogenesis [vascular endothelial growth factor (VEGF)] and inflammation [tumor necrosis factor-α (TNF-α)]. The stimulatory effect of adenosine on HIF-1α and its target genes was essentially exerted by activation of A2A through p44/42 and A2B subtypes via p38 mitogen-activated protein kinases (MAPKs) and Akt phosphorylation. Furthermore the nucleoside raised VEGF and decreased TNF-α levels, by activating A2B subtypes. In conclusion adenosine increases GLUT-1 and iNOS gene expression in a HIF-1α-dependent way, through A2A and A2B receptors, suggesting their role in the regulation of microglial cells function following injury. However, inhibition of TNF-α adds an important anti-inflammatory effect only for the A2B subtype. GLIA 2015;63:1933-1952.

Multiple sclerosis (MS) is an autoimmune-mediated inflammatory disease characterized by multifocal areas of demyelination. Experimental evidence indicates that A2A adenosine receptors (ARs) play a pivotal role in the inhibition of inflammatory processes. The aim of this study was to investigate the contribution of A2A ARs in the inhibition of key pro-inflammatory mediators for the pathogenesis of MS. In lymphocytes from MS patients, A1, A2A, A2B, and A3 ARs were analyzed by using RT-PCR, Western blotting, immunofluorescence, and binding assays. Moreover the effect of A2A AR stimulation on proinflammatory cytokine release such as TNF-α, IFN-γ, IL-6, IL-1β, IL-17, and on lymphocyte proliferation was evaluated. The capability of an A2A AR agonist on the modulation of very late antigen (VLA)-4 expression and NF-κB was also explored. A2A AR upregulation was observed in lymphocytes from MS patients in comparison with healthy subjects. The stimulation of these receptors mediated a significant inhibition of TNF-α, IFN-γ, IL-6, IL-1β, IL-17, and cell proliferation as well as VLA-4 expression and NF-κB activation. This new evidence highlights that A2A AR agonists could represent a novel therapeutic tool for MS treatment as suggested by the antiinflammatory role of A2A ARs in lymphocytes from MS patients.

BACKGROUND AND PURPOSE Among several pharmacological properties, analgesia is the most common feature shared by either opioid or cannabinoid systems. Cannabinoids and opioids are distinct drug classes that have been historically used separately or in combination to treat different pain states. In the present study, we characterized the signal transduction pathways mediated by cannabinoid CB2 and µ-opioid receptors in quiescent and LPS-stimulated murine microglial cells. EXPERIMENTAL APPROACH We examined the effects of µ-opioid and CB2 receptor stimulation on phosphorylation of MAPKs and Akt and on IL-1β, TNF-α, IL-6 and NO production in primary mouse microglial cells. KEY RESULTS Morphine enhanced release of the proinflammatory cytokines, IL-1β, TNF-α, IL-6, and of NO via µ-opioid receptor in activated microglial cells. In contrast, CB2 receptor stimulation attenuated morphine-induced microglial proinflammatory mediator increases, interfering with morphine action by acting on the Akt-ERK1/2 signalling pathway. CONCLUSIONS AND IMPLICATIONS Because glial activation opposes opioid analgesia and enhances opioid tolerance and dependence, we suggest that CB2 receptors, by inhibiting microglial activity, may be potential targets to increase clinical efficacy of opioids.

Background and purpose Cannabinoid (CB) receptor agonists have potential utility as anti-inflammatory drugs in chronic immune inflammatory diseases. In the present study, we characterized the signal transduction pathways affected by CB(2) receptors in quiescent and lipopolysaccharide (LPS)-stimulated murine microglia. Experimental approach We examined the effects of the synthetic CB(2) receptor ligand, JWH-015, on phosphorylation of MAPKs and NO production. Key results Stimulation of CB(2) receptors by JWH-015 activated JNK-1/2 and ERK-1/2 in quiescent murine microglial cells. Furthermore, CB(2) receptor activation increased p-ERK-1/2 at 15 min in LPS-stimulated microglia. Surprisingly, this was reduced after 30 min in the presence of both LPS and JWH-015. The NOS inhibitor L-NAME blocked the ability of JWH-015 to down-regulate the LPS-induced p-ERK increase, indicating that activation of CB(2) receptors reduced effects of LPS on ERK-1/2 phosphorylation through NO. JWH-015 increased LPS-induced NO release at 30 min, while at 4 h CB(2) receptor stimulation had an inhibitory effect. All the effects of JWH-015 were significantly blocked by the CB(2) receptor antagonist AM 630 and, as the inhibition of CB(2) receptor expression by siRNA abolished the effects of JWH-015, were shown to be mediated specifically by activation of CB(2) receptors. Conclusions and implications Our results demonstrate that CB(2) receptor stimulation activated the MAPK pathway, but the presence of a second stimulus blocked MAPK signal transduction, inhibiting pro-inflammatory LPS-induced production of NO. Therefore, CB(2) receptor agonists may promote anti-inflammatory therapeutic responses in activated microglia.

There is variable emphasis on dialysis-specific training among US nephrology fellowship programs. Our study objective was to determine the association between nephrology training experience and subsequent clinical practice. We conducted a national survey of clinical nephrologists using a fax-back survey distributed between March 8, 2010 and April 30, 2010 (N = 629). The survey assessed the time distribution of clinical practice, self-assessment of preparedness to provide care for dialysis patients at the time of certification examination, distribution of dialysis modality among patients, and nephrologists' choice of dialysis modality for themselves if their kidneys failed. While respondents spent 28% of their time caring for dialysis patients, 38% recalled not feeling very well prepared to care for dialysis patients when taking the nephrology certification examination. Sixteen percent obtained additional dialysis training after fellowship completion. Only 8% of US dialysis patients use home dialysis; physicians very well prepared to care for dialysis patients at the time of certification or who obtained additional dialysis training were significantly more likely to provide care to home peritoneal dialysis patients. Even though 92% of US dialysis patients receive thrice weekly in-center hemodialysis, only 6% of nephrologists selected this for themselves; selection of therapy for self was associated with dialysis modalities used by their patients. Nephrology training programs need to ensure that all trainees are very well prepared to care for dialysis patients, as this is central to nephrology practice. Utilization of dialysis therapies other than standard hemodialysis is dependent, in part, on training experience.

Fusarium solani is a species complex (FSSC) containing isolates that cause diseases in important crops such as root and fruit rot of Cucurbita spp., root and stem rot of pea, sudden death syndrome of soybean, foot rot of bean and dry rot of potato tubers during storage. Based on host range tests, F. solani were subdivided into different formae specialis (f. sp.) and varieties, while DNA sequences of 28S rDNA, internally transcribed spacers (ITS) rDNA and elongation factor (EF-1α) distinguished the ‘F. solani complex’ in 50 subspecific lineages. In this study we characterized, by cultural, morphological and molecular criteria, 34 isolates of F. solani obtained from potato, other crops and soil. The 34 isolates in the FSSC showed wide variability for their cultural, morphological and molecular traits. The wide variability observed with amplified fragment-length polymorphism (AFLP) and mini-microsatellite analyses is in agreement with the polymorphism observed, in a previous study, within FSSC. Nine of 34 isolates in the FSSC, classified as F. solani var. coeruleum, were morphologically distinguishable from the other F. solani isolates but they were distributed in different clusters; moreover, the nine isolates showed instability of the coeruleum pigmentation of the colonies, supporting the ambiguity of the taxa of this variety of F. solani. Using sequence data from ITS plus 5.8S rDNA region, the isolates were classified into different clades. In particular eight isolates were classified into a well-supported clade including F. solani f. sp. pisi, nine into a clade including only isolates of F. solani f. sp. radicicola and four into a clade including F. solani f. sp. cucurbitae, but this classification could not be used if is not in agreement with host specificity. Two of the nine F. solani var. coeruleum isolates were phylogenetically distinct from all the other FSSC strains.

Brain-derived neurotrophic factor (BDNF) exerts its trophic effects by acting on the high-affinity specific receptor trkB. BDNF also modulates synaptic transmission in several areas of the CNS, including the spinal cord dorsal horn, where it acts as a pain modulator by yet incompletely understood mechanisms. Spinal neurons are the main source of trkB in lamina II (substantia gelatinosa). Expression of this receptor in dorsal root ganglion (DRG) cells has been a matter of debate, whereas a subpopulation of DRG neurons bears trkA receptors and contains BDNF. By the use of two different trkB antibodies we observed that 7.7% and 10.8% of DRG neurons co-expressed BDNF + trkB but not trkA, respectively, in rat and mouse. Ultrastructurally, full-length trkB (fl-trkB) receptors were present at somato-dendritic membranes of lamina II neurons (rat: 66.8%; mouse: 73.8%) and at axon terminals (rat: 33.2%; mouse: 26.2%). In both species, about 90% of these terminals were identified as primary afferent fibres (PAFs) considering their morphology and/or neuropeptide content. All fl-trkB-immunopositive C boutons in type Ib glomeruli were immunoreactive for BDNF and, at individual glomeruli and axo-dendritic synapses, fl-trkB receptors were located in a mutually exclusive fashion at pre- or postsynaptic membranes. Thus, only a small fraction of fl-trkB-immunoreactive dendrites were postsynaptic to BDNF-immunopositive PAFs. This is the first ultrastructural description of fl-trkB localization at synapses between first- and second-order sensory neurons in lamina II, and suggests that BDNF may be released by fl-trkB-immunopositive PAFs to modulate nociceptive input in this lamina of dorsal horn.

Existence of the gastro-intestinal peptide secretin in the CNS has been a matter of debate, and contrasting results have been reported, altogether indicating that the CNS is not a major site of production of this peptide. A thorough analysis was conducted in brain of transgenic mice in which the expression of the early region of simian virus 40 large T antigen (Tag) is under control of the rat secretin gene promoter. We studied Tag expression in the brains of E14-P90 transgenic mice as well as secretin mRNA and protein expression in transgenic and control CD1 mice at corresponding developmental stages. We show here a perfect correspondence of Tag and secretin mRNA expression in the mesencephalon of transgenic and normal mice between E14 and birth. In embryos, Tag is also expressed in the spinal cord, as well as in several areas of the peripheral nervous system. Localization of Tag in P0-P90 animals becomes restricted to a single compact cellular mass in mesencephalon at the level of the dorsal raphe, raphe magnus and lateral paragigantocellular nuclei. Neurons of these nuclei display secretin mRNA from E14 to birth, in both control CD1 and transgenic mice. Approximately half of these secretin-expressing neurons are immunoreactive for serotonin (5HT) and/or tryptophan hydroxylase. These results demonstrate that the secretin gene is transiently expressed in mouse serotoninergic mesencephalic neurons during development. In addition our data suggest a trophic role for secretin on neurons known to be involved in multiple superior functions in the normal brain, and lost in neurodegenerative disorders.

Adenosine is an endogenous modulator of a large variety of physiological functions through the interaction with specific cell membrane G-protein-coupled receptors classified as A 1 , A 2A , A 2B , and A 3 . Activation of A 3 receptors has been shown to stimulate phospholipase C and to inhibit adenylate cyclase. A 3 agonists also cause stimulation of phospholipase D and the release of inflammatory mediators, such as histamine from mast cells, which are responsible for inflammation and hypotension. For these reasons, the clinical use of A 3 adenosine receptors antagonists for the treatment of asthma and inflammatory disease has been suggested. Recent studies also indicated a possible employment of these derivatives as antitumor agents. Different classes of polyheterocyclic compounds have been identified as potent A 3 antagonists. Herein, we report our past and recent results in the development of tricyclic A 3 selective antagonists. The pyrazolo[4,3-e[-1,2,4-triazolo[1,5-c]pyrimidine nucleus has especially been investigated by our group. Our interests were focused on the effects of substitution of the phenyl ring of the arylcarbamoyl moiety at N 5 position and of substituents at C 9 and/or at N 8 pyrazole nitrogen. These studies allowed us to obtain a large variety of compounds which showed affinities in the nanomolar range with human A3 adenosine receptors with a high degree of selectivity vs. all other receptors subtypes. Thanks to the introduction of alkylating groups at p-position of the N 5 -phenylcarbamoyl chain, we succeeded in realizing potent irreversible A 3 adenosine antagonists. Finally, the replacement of the phenyl nucleus of carbamoyl function with a pyridine ring conferred water solubility to the corresponding derivatives, which are also characterized by high levels of As affinity and selectivity.

The present study describes the effect of low frequency, low energy, pulsing electromagnetic fields (PEMFs) on A2A adenosine receptors in human neutrophils. Saturation experiments performed using a high affinity adenosine antagonist [3H]-ZM 241385 revealed a single class of binding sites in control and in PEMF-treated human neutrophils with similar affinity (KD=1.05±0.10 and 1.08±0.12 nM, respectively). Furthermore, after 1 h of exposure to PEMFs the receptor density was statistically increased (P

1. The present work characterizes, from a pharmacological and biochemical point of view, adenosine receptors in the human malignant melanoma A375 cell line. 2. Adenosine receptors were detected by RT - PCR experiments. A1 receptors were characterized using [3H]-DPCPX binding with a KD of 1.9+/-0.2 nM and Bmax of 23+/-7 fmol x mg(-1) of protein. A2A receptors were studied with [3H]-SCH 58261 binding and revealed a KD of 5.1+/-0.2 nM and a Bmax of 220+/-7 fmol x mg(-1) of protein. A3 receptors were studied with the new A3 adenosine receptor antagonist [3H]-MRE 3008F20, the only A3 selective radioligand currently available. Saturation experiments revealed a single high affinity binding site with KD of 3.3+/-0.7 nM and Bmax of 291+/-50 fmol x mg(-1) of protein. 3. The pharmacological profile of radioligand binding on A375 cells was established using typical adenosine ligands which displayed a rank order of potency typical of the different adenosine receptor subtype. 4. Thermodynamic data indicated that radioligand binding to adenosine receptor subtypes in A375 cells was entropy- and enthalpy-driven. 5. In functional assays the high affinity A2A agonists HE-NECA, CGS 21680 and A2A - A2B agonist NECA were able to increase cyclic AMP accumulation in A375 cells whereas A3 agonists Cl-IB-MECA, IB-MECA and NECA were able to stimulate Ca2+ mobilization. In conclusion, all these data indicate, for the first time, that adenosine receptors with a pharmacological and biochemical profile typical of the A1, A2A, A2B and A3 receptor subtype are present on A375 melanoma cell line.

The present work was devoted to the study of A3 adenosine receptors in Jurkat cells, a human leukemia line. The A3 subtype was found by means of RT-PCR experiments and characterized by using the new A3 adenosine receptor antagonist [3H]-MRE 3008F20, the only A3 selective radioligand currently available. Saturation experiments revealed a single high affinity binding site with KD of 1.9±0.2 nM and Bmax of 1.3±0.1 pmol mg−1 of protein. The pharmacological profile of [3H]-MRE 3008F20 binding on Jurkat cells was established using typical adenosine ligands which displayed a rank order of potency typical of the A3 subtype. Thermodynamic data indicated that [3H]-MRE 3008F20 binding to A3 subtype in Jurkat cells was entropy- and enthalpy-driven, according with that found in cells expressing the recombinant human A3 subtype. In functional assays the high affinity A3 agonists Cl-IB-MECA and IB-MECA were able to inhibit cyclic AMP accumulation and stimulate Ca2+ release from intracellular Ca2+ pools followed by Ca2+ influx. The presence of the other adenosine subtypes was investigated in Jurkat cells. A1 receptors were characterized using [3H]-DPCPX binding with a KD of 0.9±0.1 nM and Bmax of 42±3 fmol mg−1 of protein. A2A receptors were studied with [3H]-SCH 58261 binding and revealed a KD of 2.5±0.3 nM and a Bmax of 1.4±0.2 pmol mg−1 of protein. In conclusion, by means of the first antagonist radioligand [3H]-MRE 3008F20 we could demonstrate the existence of functional A3 receptors on Jurkat cells. British Journal of Pharmacology (2001) 134, 116–126; doi:10.1038/sj.bjp.0704254

A series of novel pyrazolo[4,3-e]1,2,4-triazolo[1,5-c]pyrimidine substituted at N 8 pyrazole nitrogen and at the 5-amino group was synthesized and their affinities to all four cloned human adenosine receptor subtypes were evaluated by competition binding assays using [ 3 H]-DPCPX (A 1 and A 2B ), [ 3 H]-SCH 58261 (A 2A ), and [ 3 H]-MRE3008-F20 (A 3 ) as radioligands. In particular, the structural requirements necessary for adenosine A 2B receptor recognition were investigated. These preliminary results confirm that the free amino group at the 5-position confers better A 2B affinity, while the effect of the chain at nitrogen pyrazole nucleus, the 8-position, seems to be preferred with respect to the corresponding N 7 regioisomers. The introduction of an aminoacyl chain at the 5-amino group produces better selectivity for A 2B receptors vs. A 2A , but the compounds still remain more potent for A 1 and a significant decrease (about 5-fold) of affinity at A 2B receptors was observed. Surprisingly, with these polar chains a good affinity at human A 3 adenosine receptors was also detected. The most interesting compounds in binding studies proved to be potent antagonists (nM range) in functional assays, measuring the inhibition of cAMP production induced by 100 nM NECA.

Adenosine regulates many physiological functions by interaction with four different G-protein-coupled receptors classified as A1, A2A, A2B, and A3. While adenosine A1 and A2A receptor subtypes have been pharmacologically characterized through the use of selective ligands, the A2B and A3 adenosine receptor subtypes are presently under study in order to better understand their physio-pathological functions. In particular, activation of adenosine A3 receptors has been shown to stimulate phospholipase C and D and to inhibit adenylate cyclase. Activation of A3 adenosine receptors also causes the release of inflammatory mediators such as histamine from mast cells, which are responsible for processes such as inflammation and hypotension. For these reasons, it has been suggested that A3 adenosine receptor antagonists can be considered potential drugs for the treatment of asthma and inflammation. In the last few years different classes of heterocyclic compounds have been identified as A3 adenosine antagonists, but none of the tested compounds showed significant selectivity for A3 adenosine receptor subtype. Herein, we report our recent results on a class of pyrazolo[4,3-e]1,2,4-triazolo[1,5-c]pyrimidine derivatives as a new class of potent and selective human A3 adenosine receptor antagonists. The full characterization of the first high-affinity radioligand antagonist for this receptor subtype, designated [3H] MRE3008F20, is briefly summarized. Drug Dev. Res. 52:406–415, 2001. © 2001 Wiley-Liss, Inc.

Several studies have evidenced the opposite role played by dopamine and adenosine receptors in the control of motor behavior. In line with those studies, we have previously shown that the acute administration of the A 2A receptor antagonist SCH 58261 potentiated the turning behavior induced by L-DOPA in the unilateral 6-hydroxydopamine (6-OHDA) rat model of Parkinson's disease (PD), suggesting that selective adenosine A 2A receptor antagonists might be useful as adjuncts to L-DOPA therapy. One of the most important problems in the treatment of PD is to find a drug regimen effective after chronic administration and devoid of dyskinesia-like side effects. Previous studies have shown that the sensitized turning response, developed in 6-OHDA-lesioned rats after chronic intermittent L-DOPA, is a useful model of dyskinesia. In the present study, we evaluated the effect of a chronic administration of SCH 58261 alone or in combination with L-DOPA in 6-OHDA lesioned rats in order to verify the effectiveness of SCH 58261 after repeated administration and its dyskinetic potential. Repeated administration of SCH 58261 (5 mg/kg) did not produce tolerance to its ability to potentiate L-DOPA-turning behavior. Moreover, chronic intermittent SCH 58261 (5 mg/kg) plus L-DOPA produced a stable turning behavior response during the course of the treatment, whereas L-DOPA alone produced a progressive increase in turning behavior intensity and duration (sensitization). These results suggest that SCH 58261 is effective in potentiating L-DOPA-induced turning behavior even after a chronic treatment and it does not produce, in combination with L-DOPA, motor response alterations. A 2A receptor antagonists could be a new and useful tool for the treatment of PD.

1 The present study describes the labelling of the nociceptin (NC) receptor, ORL1, in mouse forebrain membranes with a new ligand partially protected from metabolic degradation at the C-terminal; the ligand, [3H]-NC-NH2, has a specific activity of 24.5 Ci mmol−1 2 Saturation experiments revealed a single class of binding sites with a KD value of 0.55 nm and Bmax of 94 fmol mg−1 of protein. Non specific binding was 30% of total binding. Kinetic binding studies yielded the following rate constants: Kobs=0.104 min−1; K1=0.034 min−1; T1/2=20 min; K+1=0.07 min nm−1. 3 Thermodynamic analyses indicated that [3H]-NC-NH2 binding to the mouse ORL1 is totally entropy driven, similar to what has been observed for the labelled agonists to the opioid receptors OP1(δ), OP2(κ) and OP3(μ). 4 Receptor affinities of several NC fragments and analogues, including the newly discovered ORL-1 receptor antagonist [Phe1ψ(CH2-NH)Gly2]NC(1–13)-NH2 ([F/G]NC(1–13)-NH2), were also evaluated in displacement experiments. The competition curves for these compounds were found to be parallel to that of NC and the following order of potency was determined for NC fragments: NC-OH=NC-NH2=NC(1–13)-NH2 >> NC(1–12)-NH2 > NC(1–13)-OH >> NC(1–11)-NH2, and for NC and NC(1–13)-NH2 analogues: [Tyr1]NC-NH2 [Leu1]NC(1–13)-NH2 [Tyr1]NC(1–13)-NH2 [F/G]NC(1–13)-NH2 >> [Phe3]NC(1–13)-NH2 > [DF/G]NC(1–13)-NH2. 5 Standard opioid receptor ligands (either agonists or antagonists) were unable to displace [3H]-NC-NH2 binding when applied at concentrations up to 10 μm indicating that this new radioligand interacts with a non opioid site, probably the ORL1 receptor. British Journal of Pharmacology (1998) 125, 1485–1490; doi:10.1038/sj.bjp.0702226

Recent studies have clearly shown that the adenosine A 2A receptors are present in a variety of peripheral tissues, including smooth muscle cells, heart muscle and coronary arteries, and human circulating blood elements. This paper reviews the studies performed by our research group on the A 2A receptors on human platelets, lymphocytes, and neutrophils. Affinity and potency of typical adenosine receptor ligands were compared in binding and functional studies as adenylyl cyclase, aggregation, and superoxide anion production assays. Saturation experiments, performed by using the selective A 2A adenosine receptor antagonist [ 3 H]SCH 58261 (5-amino-/-(2-phenylethyl)-2-(2-turyl)-pyrazolo-[4,3-e]-1,2,4-triazolo-[1,5c] pyrimidine) revealed a single class of binding sites in all different preparations examined with affinity values in the nanomolar range (0.85-1.34 nM) and Bmax values ranging from 35 to 80 fmol/mg protein. Competition experiments showed that the potency order of agonists and antagonists studied was similar in all human circulating blood elements. In the functional assays, the same compounds exhibited a rank order of potency identical to that observed in binding experiments. Moreover, an excellent rank order correlation was found between cAMP accumulation, aggregation, and superoxide anion production data by adenosine receptor agonists and antagonists examined. Thermodynamic data indicated that [ 3 H]SCH 58261 binding to human lymphocytes and neutrophils is entropy and enthalpy driven, a finding in agreement with the thermodynamic behaviour of antagonists binding to rat striatal A 2A adenosine receptors.

Naturally occurring apoptotic cells have been demonstrated in the postnatal cerebellum of rodents (Wood et al. [1993] Neuron 11:621–632; Krueger et al. [1995] J. Neurosci. 15:3366–3374). The nature of these cells differs among species: they are considered to be granule cells in mouse and astrocytes in rat. We labeled proliferating and apoptotic cells in the postnatal human cerebellar cortex by using antibodies against the Ki-67/proliferating cell nuclear antigen and the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling method for fragmented DNA. We also immunocytochemically detected some proteins encoded by genes modulating apoptosis and specific markers of neuronal/glial differentiation. Proliferating cells were observed from birth to 4 months, representing 31–35% of cells within the external granular layer (EGL). Apoptotic cells were detected during the first 3 months and corresponded to 5–7% of EGL cells. Much lower percentages were calculated in other cortical layers and white matter. The balance between proliferation and apoptosis was quantitatively favorable to the latter during the first postnatal week. Expression of BCL-2, CPP32, and interleukin-1β-converting enzyme (ICE) proteins was spatially and developmentally regulated in parallel with apoptosis. Apoptotic cells were often CPP32/ICE immunoreactive but negative for BCL-2. Some apoptotic cells were positive for vimentin and, less frequently, for α-internexin or type-III β tubulin, but never expressed the glial fibrillary acidic protein. This study demonstrates that apoptosis is a significant phenomenon in early postnatal development of human cerebellar cortex and shares some of the regulatory mechanisms described in other vertebrates. J. Comp. Neurol. 399:359–372, 1998. © 1998 Wiley-Liss, Inc.

The synaptic connections of two types of cone bipolar cells in the rabbit retina were studied with the electron microscope after labeling in vitro with 4′,6-diamidino-2-phenylindole (DAPI), intracellular injection with Lucifer Yellow, and photooxidation (Mills and Massey [1992] J. Comp. Neurol. 321:133). Both types of bipolars belong to the flat variety, because they make basal junctions with a group of four to ten neighboring cone pedicles. One cell type has an axonal arborization that occupies strata 1 through 3 of the inner plexiform layer (IPL). At ribbon synaptic junctions, it is presynaptic to ganglion cell dendrites and to reciprocal dendrites belonging to narrow-field bistratified (AII) amacrine cells. In addition, it contacts and is contacted by other amacrine cell processes of unknown origin. The other cell type has an axonal arborization entirely confined to stratum 2 of the IPL; it is pre- or postsynaptic to a pleomorphic population of amacrine cell processes, and, in particular, it receives input from the lobular appendages of AII. Thus, these two bipolar types probably belong to the off-variety because they make basal junctions with cone photoreceptors and send their axon to sublamina α of the IPL, which is occupied by the dendrites of off-ganglion cells. They are also part of the rod pathway because they receive input from AII amacrine cells. © 1996 Wiley-Liss, Inc.