Inhibition of spinal cytosolic phospholipase A(2) expression by an antisense oligonucleotide attenuates tissue injury-induced hyperalgesia.

Activation of the spinal phospholipase A(2) (PLA(2)) -cyclooxygenase (COX) -prostaglandin signaling pathway is widely implicated in nociceptive processing. Although the role of spinal COX isoforms in pain signal transmission has been extensively characterized, our knowledge of PLA(2) enzymes in this cascade is limited. Among all PLA(2) groups, cytosolic calcium-dependent PLA(2) group IVA (cPLA(2)IVA) appears to be the predominant PLA(2) enzyme in the spinal cord. In the present study we sought to (i) characterize anatomical and cellular distribution and localization of cPLA(2)IVA in dorsal horn of rat spinal cord, (ii) verify efficacy and selectivity of intrathecal (IT) delivery of an antisense oligonucleotide (AS) targeting rat cPLA(2)IVA mRNA on spinal expression of this enzyme, and (iii) examine the effect of down-regulation of spinal cPLA(2)IVA on peripheral tissue injury-induced pain behavior. Here we demonstrate that cPLA(2)IVA is constitutively expressed in rat spinal cord, predominantly in dorsal horn neurons and oligodendrocytes but not in astrocytes or microglia. Intrathecal injection of AS significantly down-regulated both protein and gene expression of cPLA(2)IVA in rat spinal cord, while control missense oligonucleotide (MS) had no effect. Immunocytochemistry confirmed that the reduction occurred in neurons and oligodendrocytes. cPLA(2)IVA AS did not alter expression of several other PLA(2) isoforms, such as secretory PLA(2) (groups IIA and V) and calcium-independent PLA(2) (group VI), indicating that the AS was specific for cPLA(2)IVA. This selective knockdown of spinal cPLA(2)IVA did not change acute nociception (i.e. paw withdrawal thresholds to acute thermal stimuli and intradermal formalin-induced first phase flinching), however, it significantly attenuated formalin-induced hyperalgesia (i.e. second phase flinching behavior), which reflects spinal sensitization. Thus the present findings suggest that cPLA(2)IVA may specifically participate in spinal nociceptive processing.

Rapid stent-supported revascularization in acute ischemic stroke.

We report the case of a patient with an acute middle cerebral artery occlusion emergently revascularized with a Neuroform self-expanding stent.

Metabolism and excretion of peptide leukotrienes in the anesthetized rat.

The metabolism and excretion of the peptide leukotrienes C4, D4, E4 and N-acetylleukotriene E4 have been studied in the anesthetized rat. The intravenous administration of [3H]leukotriene C4 (2.6 X 10(-11) mol/kg) showed a rapid clearance of radioactivity from the blood and a time-related biliary excretion, recovering 69 +/- 1.6% (n = 6) over 60 min. Less than 1% of total radioactivity was recovered in the urine over the same time period. Similarly, the intravenous administration of [3H]leukotriene D4 (2.5 X 10(-11) mol/kg), [3H]leukotriene E4 (2.5 X 10(-11) mol/kg) and N-acetyl[3H]leukotriene E4 (2.1 X 10(-11) mol/kg) showed a 62 +/- 7.5% (n = 4), 52 +/- 1.5% (n = 4) and 37 +/- 4.6% (n = 5) biliary recovery of radioactivity, respectively, after 60 min. Examination of bile identified leukotriene D4 and N-acetylleukotriene E4 as the main products, although substantial radioactivity, which probably represents unidentified polar products, was present at the solvent fronts of the reverse-phase HPLC. Time course studies indicated a relatively rapid conversion of leukotriene C4 to leukotriene D4, while leukotriene D4 metabolism appeared to be much slower. Leukotriene E4 was a minor product, suggesting that the N-acetylation process is rapid. Incubation of [3H]leukotriene C4 in rat plasma and whole blood in vitro resulted in a slow conversion of leukotriene C4 to leukotriene D4 and leukotriene E4 only. These data suggest that the majority of the leukotriene metabolism and excretion in vivo in the anesthetized rat occurs predominantly in the hepatic system. We conclude that this model is suitable for the measurement of in vivo production of peptide leukotrienes.

Activation of leukocyte movement and displacement of [3H]leukotriene B4 from leukocyte membrane preparations by (12R)- and (12S)-hydroxyeicosatetraenoic acid.

Both (12R)- and (12S)-hydroxyeicosatetraenoic acid were demonstrated to produce aggregation of rat leukocytes and enhance human leukocyte chemokinesis. (12R)-Hydroxyeicosatetraenoic acid was 10-20-fold more potent than (12S)-hydroxyeicosatetraenoic acid but at least 500-fold less potent than leukotriene B4 in these assays. These relative potencies are correlated with the potencies of (12R)- and (12S)-hydroxyeicosatetraenoic acid for competition of [3H]leukotriene B4 binding to rat and human leukocyte membrane preparations.

Mechanisms of antinociception of spinal galanin: how does galanin inhibit spinal sensitization?

Galanin by a spinal action has been shown to have an antihyperalgesic action. Thus, in rats with lumbar intrathecal (IT) catheters, the thermal hyperalgesia evoked by carrageenan paw injection was blocked by IT delivery of galanin(1-29) (Gal(1-29)) and galanin(2-11) (Gal(2-11)) with the rank order of activity being Gal(1-29)>Gal(2-11). We sought to determine whether this spinal action reflects an effect upon afferent transmitter release, e.g., substance P (SP), and/or on secondary neurons, e.g., signaling postsynaptic to neurokinin 1 (NK1) receptor activation. To address the question on afferent release, we investigated the effect of IT administration of galanin on tissue injury-induced spinal NK1 internalization (an indicator of SP release). Noxious stimulation (paw compression) produced an increase in NK1 internalization in dorsal horn lamina I. IT pretreatment of rats with Gal(1-29) and Gal(2-11) significantly attenuated the evoked NK1 internalization, with the rank order of activity being Gal(1-29)>Gal(2-11)>saline. To address the question of postsynaptic action, we examined the effects of IT galanin upon IT SP-induced thermal hyperalgesia and spinal PGE2 release. Application of SP (30 nmol) directly to spinal cord led to a decrease in thermal thresholds and a profound increase in PGE(2) concentration in spinal dialysates. Both phenomena were reversed by Gal(1-29) and Gal(2-11) (10nmol, IT). These findings suggest that the antihyperalgesic effect of spinal galanin is due to its action on sites both presynaptic (inhibition of SP release) and postsynaptic (blockade of SP-evoked hyperalgesia and PGE2 production) to the primary afferents.

Spinal release of tumour necrosis factor activates c-Jun N-terminal kinase and mediates inflammation-induced hypersensitivity.

BACKGROUND: Mounting evidence points to individual contributions of tumour necrosis factor-alpha (TNF) and the c-Jun N-terminal kinase (JNK) pathway to the induction and maintenance of various pain states. Here we explore the role of spinal TNF and JNK in carrageenan-induced hypersensitivity. As links between TNF and JNK have been demonstrated in vitro, we investigated if TNF regulates spinal JNK activity in vivo. METHODS: TNF levels in lumbar cerebrospinal fluid (CSF) were measured by enzyme-linked immunosorbent assay, spinal TNF gene expression by real-time polymerase chain reaction and TNF protein expression, JNK and c-Jun phosphorylation by western blotting. The role of spinal TNF and JNK in inflammation-induced mechanical and thermal hypersensitivity was assessed by injecting the TNF inhibitor etanercept and the JNK inhibitors SP600125 and JIP-1 intrathecally (i.t.). TNF-mediated regulation of JNK activity was examined by assessing the effect of i.t. etanercept on inflammation-induced spinal JNK activity. RESULTS: TNF levels were increased in CSF and spinal cord following carrageenan-induced inflammation. While JNK phosphorylation followed the same temporal pattern as TNF, c-jun was only activated at later time points. Intrathecal injection of TNF and JNK inhibitors attenuated carrageenan-induced mechanical and thermal hypersensitivity. TNF stimulation induced JNK phosphorylation in cultured spinal astrocytes and blocking the spinal actions of TNF in vivo by i.t. injection of etanercept reduced inflammation-induced spinal JNK activity. CONCLUSIONS: Here we show that spinal JNK activity is dependent on TNF and that both TNF and the JNK signalling pathways modulate pain-like behaviour induced by peripheral inflammation.

Predictors of functional disability and mortality after status epilepticus.

The authors identified predictors of functional disability and mortality after status epilepticus in a multivariate analysis of 83 episodes in 74 patients. Twenty-one percent (14/85) of episodes were fatal. Increased age (OR = 1.1; 95% CI, 1.0 to 1.1) and acute symptomatic seizures (OR = 6.0; 95% CI, 1.2 to 30.3) were predictors of mortality. Functional outcome at discharge deteriorated in 23% (16/69) of nonfatal episodes. Increased length of hospitalization (OR = 1.04; 95% CI, 1.0 to 1.1) and acute symptomatic seizures (OR = 3.9; 95% CI, 1.0 to 14.7) were predictors of functional disability.

Development of 2,3-dihydro-6-(3-phenoxypropyl)-2-(2-phenylethyl)-5-benzofuranol (L-670,630) as a potent and orally active inhibitor of 5-lipoxygenase.

Leukotrienes are potent biological mediators of allergic and inflammatory diseases and are derived from arachidonic acid through the action of the 5-lipoxygenase. In this study, the syntheses and comparative biological activities of three series of 2,3-dihydro-2,6-disubstituted-5-benzofuranols with various substituents on position 3 are described. Compounds from each series were evaluated for their ability to inhibit the production of leukotriene B4 (LTB4) in human peripheral blood polymorphonuclear (PMN) leukocytes and the 5-lipoxygenase reaction in cell-free preparations from rat PMN leukocytes. The structure-activity relationships of each series in vitro and in vivo are presented. The bioavailability, metabolism, and toxicity profile of each series are discussed. The series with no substituent at position 3 was the most potent and among the compounds in that series 2,3-dihydro-6-(3-phenoxypropyl)-2-(2-phenylethyl)-5-benzofuranol (46, L-670,630) was chosen for further development.

Depression in Parkinson's disease.

Approximately 50% of patients with Parkinson's disease experience clinical depression. Neurotransmitter deficits in depression and Parkinson's disease suggest a common lesion may be responsible for this high incidence. In addition to similar psychological profiles, the clinical features of Parkinson's disease and depression likewise overlap making the distinction difficult. Differentiating these two diseases is very important, as each is treatable. The neuroscience nurse is in a unique position to evaluate the patient with Parkinson's disease for signs and symptoms of depression.

Parkinson's disease. Quality of life issues.

PD affects many dimensions of quality of life. This article has identified motor and nonmotor features of PD that are directly related to a patient's quality of life. Medication therapy can help to ameliorate some of the symptoms, yet side effects can be as disabling as the symptoms of PD. Nursing care should include assessment, intervention, and evaluation of both physical and psychosocial aspects of care for patients with PD to assist them in achieving maximum functioning.

Spinal matrix metalloproteinase 3 mediates inflammatory hyperalgesia via a tumor necrosis factor-dependent mechanism.

Matrix metalloproteinases (MMPs) have been implicated in the modulation of synaptic plasticity, glial activation, and long-term potentiation in the CNS. Here we demonstrate for the first time a mechanism for the regulation of nociceptive processing by spinal MMP-3 during peripheral inflammation. We first determined by western blotting that the catalytic (active) form of MMP-3 (cMMP-3) is increased in lumbar spinal cord following peripheral inflammation in rats. The peripheral inflammation-induced thermal hyperalgesia and tactile hypersensitivity was transiently (2-3 h) attenuated by intrathecal (IT) pretreatment with either an MMP-3 inhibitor (NNGH), or a broad spectrum MMP inhibitor (GM6001). In addition, IT delivery of cMMP-3 evoked hypersensitivity, whereas the pro (enzymatically inactive) form of MMP-3 did not. This suggests a pro-algesic effect of spinal MMP-3 mediated by an enzymatic mechanism. This cMMP-3-induced hypersensitivity is concurrent with increased tumor necrosis factor (TNF) in the spinal cord. The hypersensitivity behavior is prevented by intrathecal etanercept (TNF blockade). Treatment with cMMP-3 resulted in an increase in TNF release from spinal primary microglial, but not astrocyte cultures. These findings thus present direct evidence implicating MMP-3 in the coordination of spinal nociceptive processing via a spinal TNF-dependent mechanism.

Diagnostic cerebral angiography: the interventional neurology perspective.

BACKGROUND/OBJECTIVE: Cerebral angiography (CA) is increasingly used in clinical practice with advances in neurointerventional therapy. We present our CA experience performed by neurologists at an academic institution. METHOD: CA performed between July 2005 and March 2008 was reviewed. Major neurological outcome was defined as a new neurological deficit lasting >24 hours or worsening of pre-existing neurological deficit by 4 points on the National Institutes of Health Stroke Scale. Major non-neurological outcomes were defined as any death within 24 hours of the procedure, vascular injury requiring surgery, arteriovenous fistula, or pseudo-aneurysm formation and access site hematoma >5 cm, and/or requiring blood transfusion. RESULTS: In total 661 angiograms were performed over 30 months. CA indications were ischemic stroke in 210/661 (31.7%), hemorrhagic stroke in 321/661 (48.6%), trauma for 16/661 (2.4%), presurgical epilepsy workup 95/661 (14.3%), and other conditions 19/661 (2.9%). Mean age of the group was 49 +/- 18 years. Permanent neurological deficit occurred in .2% (1 patient) and reversible neurological deficits occurred in .2% (1/661). Major non-neurological complications occurred in .9% (6/661). All these rates were less than established guidelines. CONCLUSIONS: The safety and efficacy of CA performed by interventional neurologists is acceptable by current guidelines.

Measurement of antiplatelet inhibition during neurointerventional procedures: the effect of antithrombotic duration and loading dose.

BACKGROUND/OBJECTIVE: Symptomatic thromboembolic events are the most common complications associated with aneurysm coiling, and carotid and intracranial stenting. Our objective is to assess the effect of aspirin (ASA) and clopidogrel dose and duration on platelet inhibition using a point of care assay in neurointerventional (NI) suite. METHOD: The dose, duration, and point of care platelet function assay data for clopidogrel and aspirin therapy were prospectively collected between February 2006 and November 2007. Inadequate platelet inhibition for ASA was defined as >or=550 ASA reaction units (ARU), and for clopidogrel was defined as or=7 days, 300 mg for 24 hours, and 600 mg same day load had a mean P2Y12/ADP inhibition of 45%, 35% (P-value = .09), and 16%, respectively (P-value = .005). CONCLUSION: Premedication with clopidogrel, in contrast to aspirin, does not achieve adequate platelet inhibition in about two-third of the patients. Same day antiplatelet loading may be insufficient to achieve adequate platelet inhibition and should be avoided if clinically feasible.

Long term clinical and angiographic outcomes with the Wingspan stent for treatment of symptomatic 50-99% intracranial atherosclerosis: single center experience in 51 cases.

BACKGROUND AND AIM: Two independent post-approval registries have reported favorable periprocedural and short term outcomes with the use of the Wingspan stent for treatment of intracranial arterial stenosis. Data on long term clinical and imaging outcomes after Wingspan stent placement are limited. METHODS: All patients treated with the Wingspan stent in a single academic center from January 2006 to February 2008 were identified. Data on stenting indication, severity of stenosis, technical success, re-stenosis and clinical outcome were collected. RESULTS: 51 patients were treated with the Wingspan stent system for a symptomatic intracranial atherosclerotic stenosis of 50-99%. The technical success rate was 98%. The mean pre- and post-stent stenoses were 73 (11)% and 21 (7)%. Any stroke or death within 24 h of the procedure occurred in 1/51 (2%). The frequency of any stroke or death within 30 days or ipsilateral stroke beyond 30 days was 5/51 (10.0%) at a mean follow-up time of 14.6 months (range 8-30). The frequency of ≥ 50% re-stenosis on follow-up imaging was 7/29 (24%) at 8.6 (4.4) months (range 3-20); all were detected on the initial imaging within 3-6 months, and only one was symptomatic. CONCLUSION: The use of the Wingspan stent in patients with ≥50% symptomatic intracranial stenosis is associated with good long term clinical outcome. One stroke occurred after the first 30 days, suggesting a significant stabilization of the adverse event rate after the first month.

Lipoxin synthesis by arachidonate 5-lipoxygenase purified from porcine leukocytes.

Arachidonate 5-lipoxygenase purified from porcine leukocytes produced several more polar compounds from 5,15-dihydroperoxy-eicosatetraenoic acid added as such or generated from 15-hydroperoxy acid. These polar products with absorption maxima at 301-302 nm and shoulders at 289 nm and 316-317 nm were identified as 5S,6R,15S-11-cis-lipoxin A and its 6-epimer, all-trans-lipoxin A isomers, and all-trans-lipoxin B isomers. Most of these lipoxins were presumably degradation products of a 5,6-epoxy intermediate formed by the catalysis of leukotriene A synthase, an integral part of 5-lipoxygenase. The rate of the enzymatic lipoxin synthesis from 15-hydroperoxy acid was about 6% of arachidonate 5-oxygenation.

Evidence of in-vivo omega-oxidation of peptide leukotrienes in the rat: biliary excretion of 20-CO2H N-acetyl LTE4.

In a previous study in our laboratory it was observed that after [3H] LTC4 administration (luCi/kg i.v.) to the anesthetized rat, significant amounts of injected radioactivity (approximately 25%) were associated with previously unidentified biliary polar metabolite(s). In the present study we describe the isolation and characterization of the predominant polar metabolite. Rats were injected with synthetic LTC4 (20 microgram/kg i.v.) and bile collected over 30 min. After extraction and purification (2 step RP-HPLC procedure), the retention time of the metabolite was compared (plus coinjections) and found to be identical with synthetic 20-CO2H N-Ac LTE4 in two RP-HPLC systems. Also, the UV spectrum of the biologically derived metabolite was compared and found identical to the synthetic material, giving a characteristic conjugated triene absorption in the UV with a max of 281 nm and shoulders at 270 and 290 nm. Further, the trimethyl ester derivative of the metabolite showed identical chromatographic behaviors in 2 reverse and 2 normal phase HPLC systems compared with synthetic 20-CO2H N-Ac LTE4 trimethyl ester. We conclude omega-oxidation of peptide leukotrienes occurs in the rat and that 20-CO2H N-Ac LTE4 is an in vivo product of LTC4 metabolism.

Clinical study of mianserin, imipramine and placebo in depression: blood level and MHPG correlations.

1. The clinical efficacy of mianserin, a tetracyclic compound, was compared with imipramine and placebo in 47 hospitalized depressed patients. 2. The clinical ratings showed that the three treatment groups improved equivalently during hospitalization. 3. Plasma levels of mianserin correlated with changes in the Hamilton Rating Scale for depression, total score and two of its factors (anxiety/somatization, and retardation) and the item 'late insomnia'. 4. Drowsiness was a more frequent side-effect among mianserin patients on day 4; no other side-effect distinguished the treatments. 5. No relationship between MHPG levels and treatment or treatment outcome were observed.