Pentoxifylline inhibits Vgamma9/Vdelta2 T lymphocyte activation of patients with active Behçets disease in vitro

The aim of this study is to evaluate the in vitro effect of pentoxifylline (PTX) on T Vgamma9/Vdelta2 lymphocyte function in Beh?ets disease (BD). We investigated the effect of PTX on Vgamma9/Vdelta2 T cell expansion and expression of TNFRII receptor and perforin content before and after PTX addition by means of FACS analysis lymphocyte cultures from patients with active and inactive BD and healthy subjects. The addition of PTX at a concentration of 1 mg/ml determined a significant inhibition of cell expansion, a down regulation of TNF receptor expression and inhibited the PMA-induced degranulation of perforin. Taken together these data indicate that PTX is capable of interfering with Vgamma9/Vdelta2 T cell function in BD, and although cell culture models cannot reliably predict all of the potential effects of the drug in vivo, our results encourage the possibility that this drug may find use in a range of immunological disorder characterized by dysregulated cell-mediated immunity.     

Inhibiting costimulatory activation of T cells : a viable treatment option for rheumatoid arthritis?

There is now good evidence that T cells play a central role in the inflammatory pathway that leads to the persistent synovitis that causes joint damage in rheumatoid arthritis (RA). T cells require two signals to become activated. The second step in the activation of T cells involves costimulatory pathways, the best described pathway being the binding of CD28 on T cells to CD80/86 on antigen-presenting cells. This observation has led to the development of a new category of biological response modifier. Abatacept is a fusion protein (cytotoxic T-lymphocyte-associated antigen-4 immunoglobulin [CTLA4Ig]); which blocks the binding of CD28 by avidly binding CD80/86. Without this costimulatory activation, the T cell becomes anergic.Abatacept has consistently been shown to improve the signs and symptoms of RA in phase II and phase III trials in patients with an inadequate response to methotrexate and anti-tumour necrosis factor (TNF) therapy. Onset of action is rapid and efficacy is maintained during the period of treatment. Recent trials have also provided evidence of improvement in quality-of-life measures and radiographic progression. The safety profile to date has also been favourable and supports the theory that targeting naive T cells early in the inflammatory pathway will lead to immunomodulation rather than immunosuppression. The evidence produced so far suggests that abatacept will be a useful addition to the available therapies for patients with RA.     

Submaximal PPARγ activation and endothelial dysfunction: new perspectives for the management of cardiovascular disorders

PPARγ activation plays an important role in glucose metabolism by enhancing insulin sensitization. PPARγ is a primary target for thiazolidinedione-structured insulin sensitizers like pioglitazone and rosiglitazone employed for the treatment of type 2 diabetes mellitus. Additionally, PPARγ activation inhibits adhesion cascades and detrimental vascular inflammatory events. Importantly, activation of PPARγ plays a distinctive role in regulating the physiology and expression of endothelial nitric oxide synthase (eNOS) in the endothelium, resulting in enhanced generation of vascular nitric oxide. The PPARγ activation-mediated vascular anti-inflammatory and direct endothelial functional regulatory actions could, therefore, be beneficial in improving the vascular function in patients with atherosclerosis and hypertension with or without diabetes mellitus. Despite the disappointing cardiac side effect profile of rosiglitazone-like PPARγ full agonists, the therapeutic potential of novel pharmacological agents targeting PPARγ submaximally cannot be ruled out. This review discusses the potential regulatory role of PPARγ on eNOS expression and activation in improving the function of vascular endothelium. We argue that partial/submaximal activation of PPARγ could be a major target for vascular endothelial functional improvement. Interestingly, newly synthesized partial agonists of PPARγ such as balaglitazone, MBX-102, MK-0533, PAR-1622, PAM-1616, KR-62776 and SPPARγM5 are devoid of or have a reduced tendency to cause the adverse effects associated with full agonists of PPARγ. We propose that the vascular protective properties of pharmacological agents, which submaximally activate PPARγ, should be investigated. Moreover, the therapeutic opportunities of agents that submaximally activate PPARγ in preventing vascular endothelial dysfunction (VED) and VED-associated cardiovascular disorders are discussed.     

A molecular model for an anionic opiate μ-receptor: affinity and activation of morphine conformers

In this study, the minimal neglect of differential overlap, hydrogen bonding corrected (MNDO/H) method was used to construct an explicit three component μ-opioid receptor binding site composed of formate (Glu⁻, Asp⁻), H₂O (Ser, Thr) and NH₄⁺ (Lys⁺, Arg⁺) which has optimum interactions with the protonated amine and polar oxygen regions of morphine, respectively. These moieties are common to most classes of opioids and are thought to be involved in key interactions of the protonated form with the receptor leading to recognition and activation. Two predominant conformers of morphineH⁺, NMe (equatorial) and NMe (axial) were used as templates for construction of the binding site. In these studies, a plausible recognition mechanism involving electrostatic interaction between the protonated amine and an anionic receptor site, together with a proton-donating phenolic group and proton-accepting polar oxygens was characterized. The role of hydration of both the receptor site and morphine in determining affinity was also explicitly considered. The results strongly indicate that the high-affinity binding of morphineH⁺ to an ‘anionic’ receptor site is due mainly to a large entropy term resulting from expulsion of H₂O from the receptor site upon introduction of morphine. A possible mechanism of receptor activation was also explored involving proton transfer from morphine to the receptor. Two results obtained support the plausibility of this mechanism: the barrier to proton transfer is reduced by receptor interaction with the polar oxygens and a conformational change occurs in the model receptor during this process.     

Local activation and systemic dysregulation of T lymphocytes in Sjögren's syndrome

T cells are implicated in both local and systemic pathophysiology of primary Sj?gren's syndrome (PSS). Lymphocytic infiltrates in exocrine glands are dominated by CD4+ T cells, some contributing to ectopic lymphoid tissue, others, unusually, exhibiting cytotoxic potential. Cytokine secretion patterns are complex, with Th1 and Th17 components implicated in pathology. Circulating T cells exhibit phenotypes consistent with hyperactivation, cytokine imbalance, and homeostatic alterations; CD4 lymphopenia is recognized as a risk factor for developing lymphoma. Evidence of oligoclonal expansion is found locally and systemically. Functional alterations (e.g. cytokine secretion profile, migratory potential, target cell interactions) are less clearly defined. Attempts at T cell-targeted therapy of PSS have been limited, although therapy targeted at other arms of the immune response may also affect T cells. A better understanding of T-cell dysregulation in PSS is required in order to understand its contribution to disease, aid prognosis, and improve therapeutic interventions aimed at this aspect of the disease.     

Barriers,pathways and processes for uptake,translocation and accumulation of nanomaterials in plants – Critical review

Uptake, transport and toxicity of engineered nanomaterials (ENMs) into plant cells are complex processes that are currently still not well understood. Parts of this problem are the multifaceted plant anatomy, and analytical challenges to visualize and quantify ENMs in plants. We critically reviewed the currently known ENM uptake, translocation, and accumulation processes in plants. A vast number of studies showed uptake, clogging, or translocation in the apoplast of plants, most notably of nanoparticles with diameters much larger than the commonly assumed size exclusion limit of the cell walls of ～5–20?nm. Plants that tended to translocate less ENMs were those with low transpiration, drought-tolerance, tough cell wall architecture, and tall growth. In the absence of toxicity, accumulation was often linearly proportional to exposure concentration. Further important factors strongly affecting ENM internalization are the cell wall composition, mucilage, symbiotic microorganisms (mycorrhiza), the absence of a cuticle (submerged plants) and stomata aperture. Mostly unexplored are the roles of root hairs, leaf repellency, pit membrane porosity, xylem segmentation, wounding, lateral roots, nodes, the Casparian band, hydathodes, lenticels and trichomes. The next steps towards a realistic risk assessment of nanoparticles in plants are to measure ENM uptake rates, the size exclusion limit of the apoplast and to unravel plant physiological features favoring uptake.     

Neural Basis of Benzodiazepine Reward: Requirement for α2 Containing GABAA Receptors in the Nucleus Accumbens

Despite long-standing concerns regarding the abuse liability of benzodiazepines, the mechanisms underlying properties of benzodiazepines that may be relevant to abuse are still poorly understood. Earlier studies showed that compounds selective for α1-containing GABA_A receptors (α1GABA_ARs) are abused by humans and self-administered by animals, and that these receptors may underlie a preference for benzodiazepines as well as neuroplastic changes observed in the ventral tegmental area following benzodiazepine administration. There is some evidence, however, that even L-838, 417, a compound with antagonistic properties at α1GABA_ARs and agonistic properties at the other three benzodiazepine-sensitive GABA_A receptor subtypes, is self-administered, and that the α2GABA_ARs may have a role in benzodiazepine-induced reward enhancement. Using a two-bottle choice drinking paradigm to evaluate midazolam preference and an intracranial self-stimulation (ICSS) paradigm to evaluate the impact of midazolam on reward enhancement, we demonstrated that mice carrying a histidine-to-arginine point mutation in the α2 subunit which renders it insensitive to benzodiazepines (α2(H101R) mice) did not prefer midazolam and did not show midazolam-induced reward enhancement in ICSS, in contrast to wild-type controls, suggesting that α2GABA_ARs are necessary for the reward enhancing effects and preference for oral benzodiazepines. Through a viral-mediated knockdown of α2GABA_ARs in the nucleus accumbens (NAc), we demonstrated that α2 in the NAc is necessary for the preference for midazolam. Findings imply that α2GABA_ARs in the NAc are involved in at least some reward-related properties of benzodiazepines, which might partially underlie repeated drug-taking behavior.     

Consumption of non-steroidal anti-inflammatory drugs in Serbia: a comparison with Croatia and Denmark during 2005–2008

Purpose  

To analyze the amount and pattern of use of non-steroidal anti-inflammatory drugs (NSAIDs) in Serbia and to compare these parameters with those in Croatia and Denmark. The prescribing pattern of NSAIDs in Serbia as a direct indicator of physicians’ knowledge of these agents was also assessed.     

Interaction of nucleoside diphosphate kinase B with heterotrimeric G protein βγ dimers: consequences on G protein activation and stability

It is generally accepted that G protein coupled receptors (GPCR) activate heterotrimeric G proteins by inducing a GDP/GTP exchange at the G protein alpha subunit. In addition, the transfer of high energetic phosphate by nucleoside diphosphate kinase (NDPK) and/or the beta subunit of G proteins (Gbeta) can induce G protein activation. Recent evidence suggests that the NDPK isoform B (NDPK B) forms a complex with Gbetagamma dimers. In this complex, NDPK B acts as a protein histidine kinase phosphorylating Gbeta at histidine residue 266 (His266). The high energetic phosphoamidate bond on His266 allows for a phosphate transfer specifically onto GDP and thus local formation of GTP, which binds to and thereby activates the respective G protein alpha subunit. Apparently, this process occurs independent of the classical GPCR-induced GDP/GTP exchange at least for members of the G(s) and G(i) subfamilies of heterotrimeric G proteins. By using a mutant of Gbeta(1) in which His266 was replaced by Leu, it was recently demonstrated that NDPK B/Gbetagamma-mediated G(s) activation contributes by about 50% to basal cAMP formation and contractility in rat cardiac myocytes. Besides its apparent role in G protein activation, the complex formation of NDPK B with Gbetagamma dimers might be essential for G protein stability. Depletion of either the NDPK B orthologue or Gbeta(1) isoforms in zebrafish embryos led to a similar phenotype displaying contractile dysfunction in the heart accompanied by a complete loss of heterotrimeric G protein expression. In conclusion, the interaction of NDKP B with Gbetagamma dimers might play an important role in signal transduction, and alterations in this novel pathway might be of pathophysiological importance.     

Inhalation devices for long-acting β2-agonists: efficiency and ease of use of dry powder formoterol inhalers for use by patients with asthma and COPD

ABSTRACT

Background: Since the long-acting β₂-agonist bronchodilator, formoterol, first became available for the treatment of subjects with asthma or chronic obstructive pulmonary disease (COPD), generic forms of this agent have been launched in a variety of devices. It is timely to review the characteristics of the original dry powder delivery device, the single-dose Aerolizer, its in vitro performance and its comparability with other inhaler devices that are now available for delivery of formoterol.

Scope: This review focuses on the performance of the formoterol Aerolizer inhaler in comparison with other inhalers. Publically available data (PubMed) on the device performance characteristics of the Aerolizer were reviewed and summarized, together with the results of comparative studies performed by the authors. Published studies (PubMed) on patient handling and inhaler technique that include the Aerolizer are described and studies comparing the clinical effect of formoterol in the Aerolizer with formoterol delivered via other devices were reviewed and are summarized.

Findings: The Aerolizer performs consistently in dosing efficiency across a range of inspiratory flow rates, suggesting its suitability for use by patients with differing inspiratory flow abilities. The single-dose, capsule-based nature of the device provides patients with obvious feedback on whether the drug has been taken successfully and the Aerolizer has been shown to be one of the more easily used devices in comparative patient handling studies. Studies comparing the clinical effect of formoterol delivered by different inhalation devices show that formoterol via Aerolizer has an equivalent therapeutic effect.

Conclusion: Judged on the basis of dosing efficiency, ease of use and clinical equivalence, formoterol Aerolizer remains a useful option in the management of patients with asthma or COPD.     

Augmentation therapy with alpha-lipoic acid and desvenlafaxine: A future target for treatment of depression?

This study was designed to investigate the possible antidepressant effects of the antioxidant alpha-lipoic acid (ALA) as a stand-alone treatment or in association with desvenlafaxine (DVS) in the chronic corticosterone (CORT)-induced depression model. The depression model was induced by repeated administrations of CORT (20 mg/kg, subcutaneous) in mice over a period of 14 days. Between days 15 and 21, a randomized group of mice received DVS (10 or 20 mg/kg, per os [PO]), ALA (100 or 200 mg/kg, PO), or a combination of DVS (10 or 20 mg/kg, PO) and ALA (100 or 200 mg/kg, PO) along with the CORT injections for the remaining 7 days. Other groups of mice received DVS (10 or 20 mg/kg, PO) or ALA (100 or 200 mg/kg, PO) alone. Open field test, elevated plus maze (EPM) test, tail suspension test (TST), and forced swimming test (FST) were carried out 1 h after the last injection of CORT. Repeated CORT injections induced anxiety-like and depressive-like behaviors as observed by decreased open arms entries in the EPM test and increased immobility time in the TST and FST. The administration of DVS and ALA alone was able to reverse the increases in the immobility time. The combination of ALA and DVS potentiated the observed effects of DVS. These results suggest that augmentation therapy with the addition of antioxidant drugs may be an important pharmacological approach for the treatment of depression.     

γ-Tocotrienol induces apoptosis in human T cell lymphoma through activation of both intrinsic and extrinsic pathways

Tocotrienols are members of vitamin E family and possess broad biological activities including antioxidant, anti-inflammatory and antitumor effects. In the present study, we examine the potential of α-tocotrienol (AT) and γ-tocotrienol (GT) in inhibiting the proliferation of human T cell lymphoma Jurkat cells and elucidate the pathways involved in anti tumor effects of GT. GT but not AT inhibited proliferation and induced apoptosis in Jurkat cells in a dose dependent manner. GT treatment resulted in elevated mitochondrial ROS production, activation of JNK and suppression of ERK and p38 MAPK. GT also induced calcium release, loss of mitochondrial membrane potential and cytochrome c release from the mitochondria. These changes were accompanied by increase in Bax expression with a concomitant decrease in Bcl-xl expression suggesting activation of mitochondrial apoptotic pathway. GT induced increase in mitochondrial ROS was abrogated by catalase. Besides, GT also up-regulated surface expression of Fas and FasL on Jurkat cells. Further, caspase activation and PARP degradation were also seen in cells treated with GT. Inhibitors of caspase-8 and caspase-9 significantly abrogated GT mediated apoptosis. In contrast GT was not toxic to normal human peripheral blood mononuclear cells suggesting differential cytotoxicity towards normal lymphocytes and transformed lymphoma cells. Cellular uptake studies with tocotrienols showed higher intracellular accumulation of GT as compared to AT which may be responsible for its better antitumor activity. Our results show antitumor effects of GT in human lymphoma cells via increased mitochondrial ROS generation and activation of both intrinsic and extrinsic apoptotic pathways.