Nucleotide oligomerization domain 1 is a dominant pathway for NOS2 induction in vascular smooth muscle cells: comparison with Toll-like receptor 4 responses in macrophages

Background and purpose:

Gram-negative bacteria contain ligands for Toll-like receptor (TLR) 4 and nucleotide oligomerization domain (NOD) 1 receptors. Lipopolysaccharide (LPS) activates TLR4, while peptidoglycan products activate NOD1. Activation of NOD1 by the specific agonist FK565 results in a profound vascular dysfunction and experimental shock in vivo.

Experimental approach:

Here, we have analysed a number of pharmacological inhibitors to characterize the role of key signalling pathways in the induction of NOS2 following TLR4 or NOD1 activation.

Key results:

Vascular smooth muscle (VSM) cells expressed NOD1 mRNA and protein, and, after challenge with Escherichia coli or FK565, NOS2 protein and activity were induced. Macrophages had negligible levels of NOD1 and were unaffected by FK565, but responded to E. coli and LPS by releasing increased NO and expression of NOS2 protein. Classic pharmacological inhibitors for NF-κB (SC-514) and mitogen-activated protein kinase (SB203580, PD98059) signalling pathways inhibited responses in both cell types regardless of agonist. While TLR4-mediated responses in macrophages were specifically inhibited by the pan-caspase inhibitor z-VAD-fmk and the PKC inhibitor Gö6976, NOD1-mediated responses in VSM cells were inhibited by the Rip2 inhibitor PP2.

Conclusions and implications:

Our findings suggest a selective role for NOD1 in VSM cells, and highlight NOD1 as a potential novel therapeutic target for the treatment of vascular inflammation.     

Differential effects of cocaine on firing rate and pattern of dopamine neurons: role of alpha1 receptors and comparison with L-dopa and apomorphine

Psychostimulants, including cocaine, have two opposing effects on dopamine (DA) neurons: a DA-mediated inhibition and a non-DA-mediated excitation. The latter, expressed as an increase in both firing rate and a slow oscillation (SO) in firing pattern, has been shown to require forebrain inputs to DA neurons and activation of adrenergic alpha(1) receptors. However, since the effect was observed when the DA-mediated inhibition was blocked by a D2 antagonist, it is uncertain whether the underlying mechanism also plays a role in cocaine's effects in normal animals where D2-like receptors are not blocked. This study showed that under such conditions, cocaine decreased firing rate and bursting without significantly inhibiting the SO in DA neurons recorded in the ventral tegmental area. Different from cocaine, l-dopa and apomorphine, two nonpsychostimulant DA agonists known to lack the alpha(1)-mediated excitatory effect, consistently inhibited all three measures of DA cell activity. Blockade of alpha(1) receptors by prazosin did not enhance cocaine's ability to inhibit firing rate and bursting, but it did enable cocaine to inhibit the SO. These results suggest that in control rats where D2-like receptors are not blocked, alpha(1) receptors play an important role in cocaine's effect on the SO but not in its effect on firing rate and bursting of DA neurons. The maintained SO after cocaine injection may reflect continued modulation of DA neurons by forebrain inputs, regulate the pattern of DA release, and provide a temporal structure for selection of synaptic inputs to DA neurons.     

Bursting as a source of non‐linear determinism in the firing patterns of nigral dopamine neurons

Nigral dopamine (DA) neurons in vivo exhibit complex firing patterns consisting of tonic single‐spikes and phasic bursts that encode information for certain types of reward‐related learning and behavior. Non‐linear dynamical analysis has previously demonstrated the presence of a non‐linear deterministic structure in complex firing patterns of DA neurons, yet the origin of this non‐linear determinism remains unknown. In this study, we hypothesized that bursting activity is the primary source of non‐linear determinism in the firing patterns of DA neurons. To test this hypothesis, we investigated the dimension complexity of inter‐spike interval data recorded in vivo from bursting and non‐bursting DA neurons in the chloral hydrate‐anesthetized rat substantia nigra. We found that bursting DA neurons exhibited non‐linear determinism in their firing patterns, whereas non‐bursting DA neurons showed truly stochastic firing patterns. Determinism was also detected in the isolated burst and inter‐burst interval data extracted from firing patterns of bursting neurons. Moreover, less bursting DA neurons in halothane‐anesthetized rats exhibited higher dimensional spiking dynamics than do more bursting DA neurons in chloral hydrate‐anesthetized rats. These results strongly indicate that bursting activity is the main source of low‐dimensional, non‐linear determinism in the firing patterns of DA neurons. This finding furthermore suggests that bursts are the likely carriers of meaningful information in the firing activities of DA neurons.     

Follow‐up after systemic adverse reactions of immunotherapy

Out of 280 immunotherapy (IT)-treated patients in our allergy clinic, 37 (13%) developed systemic adverse reactions. Parietaria judaica (Pj) extract, a highly allergenic pollen in northern Israel, was part of the IT regimen in 46% of treated patients who developed systemic adverse reactions. Twenty-six (70%) of systemic adverse reactions occurred during the buildup phase, whereas 11 (30%) occurred in the maintenance phase of treatment. Mild systemic reactions developed in 15/37 (40%), moderate in 20/37 (54%), and severe in 2/37 (5%) of patients. In 22/37 (59% of our IT-treated patients, adverse reactions developed within 30 min after injection. Among these were the two patients with severe systemic reactions. In 19%, moderate adverse reactions appeared at 30-60 min; in 22%, mild to moderate reactions appeared after 1-2 h. Our study concludes that severe systemic reactions to IT usually appear within 30 min after injection. In Israel, IT with highly allergenic pollens such as Pj frequently causes systemic reactions, even during the maintenance phase of treatment. In such cases, the reduction of IT dosage should be more than 50% during the pollen season, and a waiting period of 1 h should also be considered.     

Use and effectiveness of dapagliflozin in routine clinical practice: An Italian multicentre retrospective study

In randomized controlled trials (RCTs), sodium‐glucose co‐transporter‐2 (SGLT2) inhibitors have been shown to confer glycaemic and extra‐glycaemic benefits. The DARWIN‐T2D (DApagliflozin Real World evIdeNce in Type 2 Diabetes) study was a multicentre retrospective study designed to evaluate the baseline characteristics of patients receiving dapagliflozin vs those receiving selected comparators (dipeptidyl peptidase‐4 inhibitors, gliclazide, or glucagon‐like peptide‐1 receptor agonists), and drug effectiveness in routine clinical practice. From a population of 281 217, the analysis included 17 285 patients initiating dapagliflozin or comparator glucose‐lowering medications (GLMs), 6751 of whom had a follow‐up examination. At baseline, participants starting dapagliflozin were younger, had a longer disease duration, higher glycated haemoglobin (HbA1c) concentration, and a more complex history of previous GLM use, but the clinical profile of patients receiving dapagliflozin changed during the study period. Dapagliflozin reduced HbA1c by 0.7%, body weight by 2.7 kg, and systolic blood pressure by 3.0 mm Hg. Effects of comparator GLMs were also within the expected range, based on RCTs. This real‐world study shows an initial channelling of dapagliflozin to difficult‐to‐treat patients. Nonetheless, dapagliflozin provided significant benefits with regard to glucose control, body weight and blood pressure that were in line with findings from RCTs.     

Internet-based surveillance of Influenza-like-illness in the UK during the 2009 H1N1 influenza pandemic

Background  

Internet-based surveillance systems to monitor influenza-like illness (ILI) have advantages over traditional (physician-based) reporting systems, as they can potentially monitor a wider range of cases (i.e. including those that do not seek care). However, the requirement for participants to have internet access and to actively participate calls into question the representativeness of the data. Such systems have been in place in a number of European countries over the last few years, and in July 2009 this was extended to the UK. Here we present results of this survey with the aim of assessing the reliability of the data, and to evaluate methods to correct for possible biases.     

Mitochondrial-related gene expression changes are sensitive to agonal-pH state: implications for brain disorders

Mitochondrial defects in gene expression have been implicated in the pathophysiology of bipolar disorder and schizophrenia. We have now contrasted control brains with low pH versus high pH and showed that 28% of genes in mitochondrial-related pathways meet criteria for differential expression. A majority of genes in the mitochondrial, chaperone and proteasome pathways of nuclear DNA-encoded gene expression were decreased with decreased brain pH, whereas a majority of genes in the apoptotic and reactive oxygen stress pathways showed an increased gene expression with a decreased brain pH. There was a significant increase in mitochondrial DNA copy number and mitochondrial DNA gene expression with increased agonal duration. To minimize effects of agonal-pH state on mood disorder comparisons, two classic approaches were used, removing all subjects with low pH and agonal factors from analysis, or grouping low and high pH as a separate variable. Three groups of potential candidate genes emerged that may be mood disorder related: (a) genes that showed no sensitivity to pH but were differentially expressed in bipolar disorder or major depressive disorder; (b) genes that were altered by agonal-pH in one direction but altered in mood disorder in the opposite direction to agonal-pH and (c) genes with agonal-pH sensitivity that displayed the same direction of changes in mood disorder. Genes from these categories such as NR4A1 and HSPA2 were confirmed with Q-PCR. The interpretation of postmortem brain studies involving broad mitochondrial gene expression and related pathway alterations must be monitored against the strong effect of agonal-pH state. Genes with the least sensitivity to agonal-pH could present a starting point for candidate gene search in neuropsychiatric disorders.     

Civil defence in a nuclear disaster

Any nuclear war would be horrific and our main aim should be universal abolition of nuclear weapons. Civil defence, with its medical attributes, could certainly increase the survival rate should a disaster occur. The effect of the explosion of a nuclear warhead is outlined, together with what could be done to reduce casualties. Nuclear winter is discussed and it is suggested that the results of computerization of doubtful surmises have been treated too much as proven facts. The possibility of its occurrence should not deter emergency planning. Civil defence can save lives, and the fact that medicine as we know it would cease to exist in an all‐out nuclear war does not excuse us from doing what we can to increase the survival rate, if the worst should happen. Action should therefore be taken now to plan decentralization of resources and to instruct the public in protection, first aid and self‐sufficiency.