Instruct: Given a scientific claim, retrieve relevant documents that support or refute the claim.
Query: Pediatric SCD patients with vaso-occlusive crisis show increased morphine use after breathing 80 ppm iNO for 4 hours.
CONTEXT Vaso-occlusion is central to the painful crises and acute and chronic organ damage in sickle cell disease. Abnormal nitric oxide-dependent regulation of vascular tone, adhesion, platelet activation, and inflammation contributes to the pathophysiology of vaso-occlusion. Nitric oxide may have promise as a mechanism-of-disease-based therapy for treatment of vaso-occlusion. OBJECTIVE To explore the efficacy and safety of inhaled nitric oxide (INO) for treatment of vaso-occlusive crisis in pediatric patients. DESIGN Prospective, double-blind, placebo-controlled, randomized clinical trial with enrollment between September 1999 and October 2001. SETTING Urban, tertiary care children's hospital in the United States. PARTICIPANTS Twenty patients aged 10 to 21 years with sickle cell disease and severe acute vaso-occlusive crisis. INTERVENTION Patients were randomly assigned to receive INO (80 ppm with 21% final concentration of inspired oxygen; n = 10), or placebo (21% inspired oxygen; n = 10) for 4 hours. MAIN OUTCOME MEASURES Change in pain at 4 hours of inhalation compared with preinhalation pain, measured on a 10-cm visual analog scale (VAS); secondary outcome measures were pain over 6 hours, parenteral narcotic use over 24 hours, duration of hospitalization, blood pressure, oxygen saturation, and methemoglobin concentration. RESULTS Preinhalation VAS pain scores were similar in the INO and placebo groups (P =.80). The decrease in VAS pain scores at 4 hours was 2.0 cm in the INO group and 1.2 cm in the placebo group (P =.37). Repeated-measures analysis of variance for hourly pain scores showed a 1-cm/h greater reduction in the INO group than the placebo group (P =.02). Morphine use over 6 hours was significantly less in the INO group (mean cumulative use, 0.29 vs 0.44 mg/kg; P =.03) but was not different over 4 hours (0.26 vs 0.32 mg/kg; P =.21) or 24 hours (0.63 vs 0.91 mg/kg; P =.15). Duration of hospitalization was 78 and 100 hours in the INO and placebo groups, respectively (P =.19). No INO toxicity was observed. CONCLUSIONS Results of this exploratory study suggest that INO may be beneficial for acute vaso-occlusive crisis. These preliminary results warrant further investigation.
To determine the relative contributions of endothelial-derived nitric oxide (NO) vs. intravascular nitrogen oxide species in the regulation of human blood flow, we simultaneously measured forearm blood flow and arterial and venous levels of plasma nitrite, LMW-SNOs and HMW-SNOs, and red cell S-nitrosohemoglobin (SNO-Hb). Measurements were made at rest and during regional inhibition of NO synthesis, followed by forearm exercise. Surprisingly, we found significant circulating arterial-venous plasma nitrite gradients, providing a novel delivery source for intravascular NO. Further supporting the notion that circulating nitrite is bioactive, the consumption of nitrite increased significantly with exercise during the inhibition of regional endothelial synthesis of NO. The role of circulating S-nitrosothiols and SNO-Hb in the regulation of basal vascular tone is less certain. We found that low-molecular-weight S-nitrosothiols were undetectable and S-nitroso-albumin levels were two logs lower than previously reported. In fact, S-nitroso-albumin primarily formed in the venous circulation, even during NO synthase inhibition. Whereas SNO-Hb was measurable in the human circulation (brachial artery levels of 170 nM in whole blood), arterial-venous gradients were not significant, and delivery of NO from SNO-Hb was minimal. In conclusion, we present data that suggest (i) circulating nitrite is bioactive and provides a delivery gradient of intravascular NO, (ii) S-nitroso-albumin does not deliver NO from the lungs to the tissue but forms in the peripheral circulation, and (iii) SNO-Hb and S-nitrosothiols play a minimal role in the regulation of basal vascular tone, even during exercise stress.
A 17-year-old boy with frequent faints due to blood-injury phobia was studied. During cardiovascular reflex investigation in our syncope unit, 50 seconds of asystole were recorded. He was treated using systematic desensitization with muscular tension and cognitive techniques by the Pediatric Psychosocial Department and has not experienced syncopal events again.
Anorectic drugs have been used for more than 30 years as an aid in weight reduction for obese persons. The use of aminorex, an amphetamine analog that increases norepinephrine levels in the central nervous system, led to an epidemic of primary pulmonary hypertension (PPH) in Europe in the late 1960s and early 1970s. The use of fenfluramine and later dexfenfluramine [drugs that inhibit 5-hydroxytryptamine (5-HT) release and reuptake and increases 5-HT and thus 5-HT secretion in the brain] was associated with a second epidemic of PPH. All of these drugs have been voluntarily withdrawn from the market. The pathogenesis of PPH in patients treated with these agents is uncertain, but recent evidence suggests that potassium channel abnormalities and vasoactive and proliferative properties of 5-HT may play a role. There is increasing experimental evidence suggesting that aminorex, fenfluramine and dexfenfluramine inhibit 4-aminopyridine-sensitive currents in potassium channels resulting in vasoconstriction in pulmonary resistance vessels and perhaps smooth muscle cell proliferation. 5-HT causes pulmonary artery vasoconstriction and smooth muscle cell proliferation. Its levels are known to be high in those with fenfluramine-induced PPH. However, a firm cause-and-effect relationship has not yet been established. One potentially beneficial effect of the epidemics of anorectic-related PPH is that it may have provided important insights into the causes of PPH unrelated to anorectic agents.
In patients with spinal cord injury, the primary or mechanical trauma seldom causes total transection, even though the functional loss may be complete. In addition, biochemical and pathological changes in the cord may worsen after injury. To explain these phenomena, the concept of the secondary injury has evolved for which numerous pathophysiological mechanisms have been postulated. This paper reviews the concept of secondary injury with special emphasis on vascular mechanisms. Evidence is presented to support the theory of secondary injury and the hypothesis that a key mechanism is posttraumatic ischemia with resultant infarction of the spinal cord. Evidence for the role of vascular mechanisms has been obtained from a variety of models of acute spinal cord injury in several species. Many different angiographic methods have been used for assessing microcirculation of the cord and for measuring spinal cord blood flow after trauma. With these techniques, the major systemic and local vascular effects of acute spinal cord injury have been identified and implicated in the etiology of secondary injury. The systemic effects of acute spinal cord injury include hypotension and reduced cardiac output. The local effects include loss of autoregulation in the injured segment of the spinal cord and a marked reduction of the microcirculation in both gray and white matter, especially in hemorrhagic regions and in adjacent zones. The microcirculatory loss extends for a considerable distance proximal and distal to the site of injury. Many studies have shown a dose-dependent reduction of spinal cord blood flow varying with the severity of injury, and a reduction of spinal cord blood flow which worsens with time after injury. The functional deficits due to acute spinal cord injury have been measured electrophysiologically with techniques such as motor and somatosensory evoked potentials and have been found proportional to the degree of posttraumatic ischemia. The histological effects include early hemorrhagic necrosis leading to major infarction at the injury site. These posttraumatic vascular effects can be treated. Systemic normotension can be restored with volume expansion or vasopressors, and spinal cord blood flow can be improved with dopamine, steroids, nimodipine, or volume expansion. The combination of nimodipine and volume expansion improves posttraumatic spinal cord blood flow and spinal cord function measured by evoked potentials. These results provide strong evidence that posttraumatic ischemia is an important secondary mechanism of injury, and that it can be counteracted.
Besides synthesizing nitric oxide (NO), purified neuronal NO synthase (nNOS) can produce superoxide (.O2-) at lower L-Arg concentrations. By using electron paramagnetic resonance spin-trapping techniques, we monitored NO and .O2- formation in nNOS-transfected human kidney 293 cells. In control transfected cells, the Ca2+ ionophore A23187 triggered NO generation but no .O2- was seen. With cells in L-Arg-free medium, we observed .O2- formation that increased as the cytosolic L-Arg levels decreased, while NO generation declined. .O2- formation was virtually abolished by the specific NOS blocker, N-nitro-L-arginine methyl ester (L-NAME). Nitrotyrosine, a specific nitration product of peroxynitrite, accumulated in L-Arg-depleted cells but not in control cells. Activation by A23187 was cytotoxic to L-Arg-depleted, but not to control cells, with marked lactate dehydrogenase release. The cytotoxicity was largely prevented by either superoxide dismutase or L-NAME. Thus, with reduced L-Arg availability NOS elicits cytotoxicity by generating .O2- and NO that interact to form the potent oxidant peroxynitrite. Regulating arginine levels may provide a therapeutic approach to disorders involving .O2-/NO-mediated cellular injury.
Cytochrome P450 (P450)-dependent metabolites of arachidonic acid, the epoxyeicosatrienoic acids (EETs), are proposed to be endothelium-derived hyperpolarizing factors (EDHF) that affect vascular tone; however, the effects of EDHF on endothelial-derived nitric oxide biosynthesis remain unknown. We examined the regulation of endothelial nitric-oxide synthase (eNOS) by EDHF and investigated the relevant signaling pathways involved. The P450 epoxygenases CYP102 F87V mutant, CYP2C11-CYPOR, and CYP2J2 were transfected into cultured bovine aortic endothelial cells, and the effects of endogenously formed or exogenously applied EETs on eNOS expression and activity were assessed. Transfection with the P450 epoxygenases led to increased eNOS protein expression, an effect that was attenuated by cotreatment with the P450 inhibitor 17-ODYA. Northern analysis demonstrated that P450 transfection led to increased eNOS mRNA levels consistent with an effect at the pretranslational level. P450 epoxygenase transfection resulted in increased eNOS activity as measured by the conversion of L-arginine to L-citrulline. Addition of synthetic EETs (50-200 nM) to the culture media also increased eNOS expression and activity. Treatment with mitogen-activated protein kinase (MAPK), MAPK kinase, and protein kinase C inhibitors apigenin, 2'-amino-3'-methoxyflavone (PD98059), and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), respectively, significantly inhibited the effects of P450 transfection on eNOS expression. Overexpression of P450 epoxygenases or addition of synthetic EETs increased Thr495 phosphorylation of eNOS, an effect that was inhibited by both apigenin and PD98059. Overexpression of P450 epoxygenases in rats resulted in increased aortic eNOS expression, providing direct evidence that EDHF can influence vascular eNOS levels in vivo. Based on this data, we conclude that EDHF up-regulates eNOS via activation of MAPK and protein kinase C signaling pathways.
Importance Although non–vitamin K antagonist oral anticoagulants (NOACs) are increasingly used to prevent thromboembolic disease, there are limited data on NOAC-related intracerebral hemorrhage (ICH). Objective To assess the association between preceding oral anticoagulant use (warfarin, NOACs, and no oral anticoagulants [OACs]) and in-hospital mortality among patients with ICH. Design, Setting, and Participants Retrospective cohort study of 141 311 patients with ICH admitted from October 2013 to December 2016 to 1662 Get With The Guidelines–Stroke hospitals. Exposures Anticoagulation therapy before ICH, defined as any use of OACs within 7 days prior to hospital arrival. Main Outcomes and Measures In-hospital mortality. Results Among 141 311 patients with ICH (mean [SD] age, 68.3 [15.3] years; 48.1% women), 15 036 (10.6%) were taking warfarin and 4918 (3.5%) were taking NOACs preceding ICH, and 39 585 (28.0%) and 5783 (4.1%) were taking concomitant single and dual antiplatelet agents, respectively. Patients with prior use of warfarin or NOACs were older and had higher prevalence of atrial fibrillation and prior stroke. Acute ICH stroke severity (measured by the National Institutes of Health Stroke Scale) was not significantly different across the 3 groups (median, 9 [interquartile range, 2-21] for warfarin, 8 [2-20] for NOACs, and 8 [2-19] for no OACs). The unadjusted in-hospital mortality rates were 32.6% for warfarin, 26.5% for NOACs, and 22.5% for no OACs. Compared with patients without prior use of OACs, the risk of in-hospital mortality was higher among patients with prior use of warfarin (adjusted risk difference [ARD], 9.0% [97.5% CI, 7.9% to 10.1%]; adjusted odds ratio [AOR], 1.62 [97.5% CI, 1.53 to 1.71]) and higher among patients with prior use of NOACs (ARD, 3.3% [97.5% CI, 1.7% to 4.8%]; AOR, 1.21 [97.5% CI, 1.11-1.32]). Compared with patients with prior use of warfarin, patients with prior use of NOACs had a lower risk of in-hospital mortality (ARD, −5.7% [97.5% CI, −7.3% to −4.2%]; AOR, 0.75 [97.5% CI, 0.69 to 0.81]). The difference in mortality between NOAC-treated patients and warfarin-treated patients was numerically greater among patients with prior use of dual antiplatelet agents (32.7% vs 47.1%; ARD, −15.0% [95.5% CI, −26.3% to −3.8%]; AOR, 0.50 [97.5% CI, 0.29 to 0.86]) than among those taking these agents without prior antiplatelet therapy (26.4% vs 31.7%; ARD, −5.0% [97.5% CI, −6.8% to −3.2%]; AOR, 0.77 [97.5% CI, 0.70 to 0.85]), although the interaction P value (.07) was not statistically significant. Conclusions and Relevance Among patients with ICH, prior use of NOACs or warfarin was associated with higher in-hospital mortality compared with no OACs. Prior use of NOACs, compared with prior use of warfarin, was associated with lower risk of in-hospital mortality.
BACKGROUND Patent ductus arteriosus (PDA) with significant left to right shunt in preterm infants increases morbidity and mortality. Early closure of the ductus arteriosus may be achieved pharmacologically using cyclooxygenase inhibitors or by surgery. The efficacy of both treatment modalities is well established. However, the preferred initial treatment of a symptomatic PDA in a preterm infant, surgical ligation or treatment with indomethacin, has not been well established. OBJECTIVES To compare the effect of surgical ligation of PDA vs. medical treatment with cyclooxygenase inhibitors (using indomethacin, ibuprofen, or mefenamic acid), each used as the initial treatment, on neonatal mortality in preterm infants with a symptomatic PDA. SEARCH STRATEGY The standard search strategy of the Cochrane Neonatal Review Group was used. This included search of electronic databases: Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2007), MEDLINE (1966 - July 2007), CINAHL (1982 - July 2007), EMBASE (1980 - July 2007); and hand search of abstracts of Pediatric Academic Societies annual meetings published in Pediatric Research (1990 - April 2002) or on line from May 2002 -July 2007. No language restrictions were applied. SELECTION CRITERIA All trials 1) using randomized or quasi-randomized patient allocation, 2) in preterm infants < 37 weeks gestational age or low-birth-weight infants (< 2500 grams) with symptomatic PDA in the neonatal period (< 28 days) and 3) comparing surgical ligation with medical treatment with cyclooxygenase inhibitors, each used as the initial treatment for closure of PDA. DATA COLLECTION AND ANALYSIS Assessment of methodological quality and extraction of data for included trials was undertaken independently by the authors. RevMan 4.1 was used for analysis of the data. MAIN RESULTS Only one study, trial B in the report of Gersony 1983, was found eligible. No additional studies were identified in the literature searches performed in July 2007. The trial compared the effect of surgical ligation of PDA vs. medical treatment with indomethacin, each used as the primary treatment. No trials comparing surgery to other cyclooxygenase inhibitors (ibuprofen, mefenamic acid) were found. Trial B of Gersony 1983 enrolled 154 infants. The study found no statistically significant difference between surgical closure and indomethacin treatment in mortality during hospital stay, chronic lung disease, other bleeding, necrotizing enterocolitis, sepsis, creatinine level, or intraventricular hemorrhage. There was a statistically significant increase in the surgical group in incidence of pneumothorax [RR 2.68 (95% CI 1.45, 4.93); RD 0.25 (95% CI 0.11, 0.38); NNH 4 (95% CI 3, 9)] and retinopathy of prematurity stage III and IV [RR 3.80 (95% CI 1.12, 12.93); RD 0.11 (95% CI 0.02, 0.20), NNH 9 (95% CI 5, 50] compared to the indomethacin group. There was as expected a statistically significant decrease in failure of ductal closure rate in the surgical group as compared to the indomethacin group: [RR 0.04 (95% CI 0.01, 0.27); RD -0.32 (95% CI -0.43, -0.21), NNT 3 (95% CI 2, 4)]. AUTHORS' CONCLUSIONS The data regarding net benefit/harm are insufficient to make a conclusion as to whether surgical ligation or medical treatment with indomethacin is preferred as initial treatment for symptomatic PDA in preterm infants. It should be noted that three recent observational studies indicated an increased risk for one or more of the following outcomes associated with PDA ligation; chronic lung disease, retinopathy of prematurity and neurosensory impairment . It is possible that the duration of the "waiting-time" and transport to another facility with surgical capacity to have the PDA ligated could adversely affect outcomes, as could the perioperative care.
BACKGROUND The role of the diffusible messenger nitric oxide (NO) in the regulation of pain transmission is still a debate of matter, pro-nociceptive and/or anti-nociceptive. S-Nitrosylation, the reversible post-translational modification of selective cysteine residues in proteins, has emerged as an important mechanism by which NO acts as a signaling molecule. The occurrence of S-nitrosylation in the spinal cord and its targets that may modulate pain transmission remain unclarified. The "biotin-switch" method and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry were employed for identifying S-nitrosylated proteins. RESULTS Here we show that actin was a major protein S-nitrosylated in the spinal cord by the NO donor, S-nitroso-N-acetyl-DL-penicillamine (SNAP). Interestingly, actin was S-nitrosylated, more in the S2 fraction than in the P2 fraction of the spinal homogenate. Treatment of PC12 cells with SNAP caused rapid S-nitrosylation of actin and inhibited dopamine release from the cells. Just like cytochalasin B, which depolymerizes actin, SNAP decreased the amount of filamentous actin cytoskeleton just beneath the membrane. The inhibition of dopamine release was not attenuated by inhibitors of soluble guanylyl cyclase and cGMP-dependent protein kinase. CONCLUSION The present study demonstrates that actin is a major S-nitrosylated protein in the spinal cord and suggests that NO directly regulates neurotransmitter release by S-nitrosylation in addition to the well-known phosphorylation by cGMP-dependent protein kinase.
AIMS The present study aims to investigate the interaction between nitric oxide (NO) and hydrogen sulfide (H(2)S), the two important gaseous mediators in rat hearts. METHODS AND RESULTS Intracellular calcium in isolated cardiomyocytes was measured with a spectrofluorometric method using Fura-2. Myocyte contractility was measured with a video edge system. NaHS (50 µM, an H(2)S donor) had no significant effect on the resting calcium level, electrically induced (EI) calcium transients, and cell contractility in ventricular myocytes. Stimulating endogenous NO production with l-arginine or exogenous application of NO donors [sodium nitroprusside (SNP) and 2-(N,N-diethylamino)-diazenolate-2-oxide] decreased myocyte twitch amplitudes accompanied by slower velocities of both cell contraction and relaxation. Surprisingly, NaHS reversed the negative inotropic and lusitropic effects of the above three NO-increasing agents. In addition, the mixture of SNP + NaHS increased, whereas SNP alone decreased, the resting calcium level and the amplitudes of EI calcium transients. Angeli's salt, a nitroxyl anion (HNO) donor, mimicked the effect of SNP + NaHS on calcium handling and myocyte contractility. Three thiols, N-acetyl-cysteine, l-cysteine, and glutathione, abolished the effects of HNO and SNP + NaHS on myocyte contraction. Neither Rp-cAMP [a protein kinase A (PKA) inhibitor] nor Rp-cGMP [a protein kinase G (PKG) inhibitor] affected the effects of SNP + NaHS, suggesting a cAMP/PKA- or cGMP/PKG-independent mechanism. CONCLUSION H(2)S may interact with NO to form a thiol sensitive molecule (probably HNO) which produces positive inotropic and lusitropic effects. Our findings may shed light on the interaction of NO and H(2)S and provide new clues to treat cardiovascular diseases.
BACKGROUND Endothelium-dependent modulation of coronary tone is impaired in the collateral-dependent coronary microcirculation. We used a porcine model of chronic coronary occlusion and collateral development to evaluate the hypothesis that exercise training enhances endothelium-mediated relaxation and increases endothelial nitric oxide synthase (ecNOS) mRNA levels of collateral-dependent microvasculature. METHODS AND RESULTS Adult female miniature swine were subjected to chronic, progressive ameroid occlusion of the proximal left circumflex coronary artery (LCx); after 2 months, animals were randomly exposed to 16-week exercise-training (EX group; treadmill running) or sedentary (SED group; cage confinement) protocols. After completion of EX or SED programs, coronary arterioles ( approximately 100 microm in diameter) were isolated from collateral-dependent LCx (distal to occlusion) and nonoccluded left anterior descending coronary artery (LAD) regions of each heart. Arterioles were studied by in vitro videomicroscopy or frozen for ecNOS mRNA analysis (RT-PCR techniques). Relaxation to the endothelium-dependent vasodilator bradykinin was decreased (P<0.05) in arterioles isolated from collateral-dependent LCx versus nonoccluded LAD regions of SED animals. Bradykinin-mediated relaxation, however, was not different in LCx versus LAD arterioles isolated from EX animals. Nitroprusside-induced relaxation was unaffected by either chronic occlusion or exercise. Importantly, ecNOS mRNA expression was significantly decreased in arterioles isolated from LCx versus LAD regions of SED animals. After training, ecNOS mRNA expression was not different between LAD and LCx arterioles. CONCLUSIONS These data indicate that exercise training enhances bradykinin-mediated relaxation of collateral-dependent LCx arterioles isolated after chronic coronary occlusion, most likely because of effects on ecNOS mRNA expression and increased production of NO.
Background: Vasoconstriction and reactive oxygen species (ROS) accumulation following contrast media (CM) injection are the key factors triggering CM-induced nephropathy. We compared the effects of N-acetylcysteine (NAC), theophylline or sodium bicarbonate on intrarenal vasoconstriction and ROS generation in a rat model of CM-induced nephropathy. Methods: Following a 3-day dehydration, Sprague-Dawley rats received CM (Telebrix) or sham ‘CM’ injection of 0.9% saline. Part of them received NAC, theophylline or bicarbonate prior to CM. Medullar renal blood flow was estimated by laser Doppler. The animals were sacrificed 1, 15 or 30 min after the respective treatments, their kidneys allocated and intrarenal STAT-8 isoprostane, PGE2 and NO assessed. Results: Vasoconstriction was significantly attenuated by NAC. Theophylline only mildly attenuated the perfusion drop at 15 min, and was ineffective following 30 min. Unlike theophylline or bicarbonate, NAC significantly augmented intrarenal PGE2. NAC, theophylline but not bicarbonate, gradually increased intrarenal NO. In all experimental variables, CM-induced ROS accumulation, represented by STAT-8 isoprostane estimation, progressed undisturbed. Conclusions: (1) CM-induced intrarenal vasoconstriction was efficiently prohibited by NAC but not bicarbonate or theophylline; (2) the vasodilatory effect of NAC was mediated via increased PGE2 synthesis, and (3) ROS accumulation was a primary renal response to CM-induced injury, not affected by any pharmacologic manipulations.
CONTEXT Dexamethasone is widely used to prevent postoperative nausea and vomiting (PONV) in pediatric tonsillectomy. OBJECTIVE To assess whether dexamethasone dose-dependently reduces the risk of PONV at 24 hours after tonsillectomy. DESIGN, SETTING, AND PATIENTS Randomized placebo-controlled trial conducted among 215 children undergoing elective tonsillectomy at a major public teaching hospital in Switzerland from February 2005 to December 2007. INTERVENTIONS Children were randomly assigned to receive dexamethasone (0.05, 0.15, or 0.5 mg/kg) or placebo intravenously after induction of anesthesia. Acetaminophen-codeine and ibuprofen were given as postoperative analgesia. Follow-up continued until the 10th postoperative day. MAIN OUTCOME MEASURES The primary end point was prevention of PONV at 24 hours; secondary end points were decrease in the need for ibuprofen at 24 hours and evaluation of adverse effects. RESULTS At 24 hours, 24 of 54 participants who received placebo (44%; 95% confidence interval [CI], 31%-59%) had experienced PONV compared with 20 of 53 (38%; 95% CI, 25%-52%), 13 of 54 (24%; 95% CI, 13%-38%), and 6 of 52 (12%; 95% CI, 4%-23%) who received dexamethasone at 0.05, 0.15, and 0.5 mg/kg, respectively (P<.001 for linear trend). Children who received dexamethasone received significantly less ibuprofen. There were 26 postoperative bleeding episodes in 22 children. Two of 53 (4%; 95% CI, 0.5%-13%) children who received placebo had bleeding compared with 6 of 53 (11%; 95% CI, 4%-23%), 2 of 51 (4%; 95% CI, 0.5%-13%), and 12 of 50 (24%; 95% CI, 13%-38%) who received dexamethasone at 0.05, 0.15, and 0.5 mg/kg, respectively (P = .003). Dexamethasone, 0.5 mg/kg, was associated with the highest bleeding risk (adjusted relative risk, 6.80; 95% CI, 1.77-16.5). Eight children had to undergo emergency reoperation because of bleeding, all of whom had received dexamethasone. The trial was stopped early for safety reasons. CONCLUSION In this study of children undergoing tonsillectomy, dexamethasone decreased the risk of PONV dose dependently but was associated with an increased risk of postoperative bleeding. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00403806.
Vascular endothelial cells produce nitric oxide (NO), which is a potent vasodilator substance and is thought to have antiatherosclerotic properties. Therefore, it has also been proposed that NO may be useful to regulate vascular tonus and prevent progression of atherosclerosis. On the other hand, NO activity reduces with aging. We previously reported that the plasma nitrite/nitrate (NOx: the stable end product of NO) concentration was significantly increased by intense aerobic exercise training in healthy young humans. We hypothesized that lifestyle modification (e.g., even mild regular exercise training) can increase NO production in previously sedentary older humans. We measured the plasma NOx concentration before and after a mild aerobic exercise training regimen (cycling on a leg ergometer at 80% ventilatory threshold for 30 min, 5 days/week) for 3 months in elderly women. In addition, we assessed the plasma concentration of cyclic guanosine monophosphate (cGMP), a second messenger of NO, in the same samples. The individual ventilatory threshold increased significantly after the 3-month exercise training. The blood pressure at rest significantly decreased after exercise training. These results suggest that the 3-month exercise training in the older women produced favorable physiological effects. The plasma concentration of NOx significantly increased by the exercise training, and the plasma concentration of cGMP also increased by the exercise training. The present study suggests that even a mild regular aerobic-endurance exercise increases NO production in previously sedentary older humans, which may have beneficial effects (i.e., antihypertensive and antiatherosclerotic effects by endogenous NO) on the cardiovascular system.
Nitric oxide (NO) is produced in the vascular endothelium and is a potent vasodilator substance that participates in the regulation of local vascular tone. Exercise causes peculiar changes in systemic and regional blood flow, i.e., an increase of systemic blood flow and a redistribution of local tissue blood flow, by which the blood flow is greatly increased in the working muscles, whereas it is decreased in some organs such as the kidney and intestine. Thus we hypothesized that exercise causes a tissue-specific change of NO production in some internal organs. We studied whether exercise affects expression of NO synthase (NOS) mRNA and protein, NOS activity, and tissue level of nitrite/nitrate (stable end products of NO) in the kidneys (in which blood flow during exercise is decreased) and lungs (in which blood flow during exercise is increased with the increase of cardiac output) of rat. Rats ran on a treadmill for 45 min at a speed of 25 m/min. Immediately after this exercise, kidneys and lungs were quickly removed. Control rats remained at rest during this 45-min period. Expression of endothelial NOS (eNOS) mRNA in the kidneys was markedly lower in exercise rats than in control rats, whereas that in the lungs was significantly higher in exercise rats than in control rats. Western blot analysis confirmed down- and upregulation of eNOS protein in the kidney and lung, respectively, after exercise. On the other hand, neither expression of neuronal NOS (nNOS) mRNA and nNOS protein nor inducible NOS (iNOS) mRNA and iNOS protein in the kidneys and lungs differed between exercise and control rats. NOS activity in the kidney was significantly lower in exercise rats than in control rats, whereas that in the lung was significantly higher in exercise rats than in control rats. On the other hand, the iNOS activity in the kidneys and lungs did not differ between exercise rats and control rats. Tissue nitrite/nitrate level in the kidneys was markedly lower in exercise rats, whereas that in the lungs was significantly higher in exercise rats. The present results show that production of NO is markedly and tissue-specifically changed in the kidney and lung by exercise.
Chronic exercise upregulates endothelial nitric oxide synthase (eNOS) gene expression. Whether the expression of inducible nitric oxide synthase (iNOS) is affected by exercise is unknown. We therefore investigated the effects of chronic exercise on iNOS and eNOS expression in isolated rat aortic endothelial and smooth muscle cells separately. Five-week-old male Wistar rats were randomly divided into control and exercise groups. After 10 weeks of running training, animals were sacrificed under ether anesthesia. The standard curve quantitative competitive reverse transcriptase-polymerase chain reaction method was used to quantify NOS mRNA expression in isolated endothelial/smooth muscle cells. To evaluate the functional role of iNOS, we examined phenylephrine-induced vascular responses with or without pretreatment with aminoguanidine. We found that (1) expression of iNOS and eNOS mRNA in endothelial cells was increased by chronic exercise and (2) chronic exercise blunted phenylephrine-induced vascular responses, probably by increasing NO release via iNOS. Our results show that chronic exercise increases both iNOS and eNOS gene expression in endothelium. These alterations may be partially responsible for the change in vascular response after exercise.
BACKGROUND Raised concentrations of nitrate and nitrite have been found in exhaled breath condensate (EBC) in airway disease, and it has been postulated that this reflects increased nitric oxide (NO) metabolism. However, the chemical and anatomical origin of nitrate and nitrite in the airways has not yet been sufficiently studied. METHODS The fraction of exhaled NO at an exhalation flow rate of 50 ml/s (FE(NO)) and nitrite and nitrate in EBC, nasal condensate, and saliva were measured in 17 tracheostomised and 15 non-tracheostomised subjects, all of whom were non-smokers without respiratory disease. Tracheal and oral samples were taken from the tracheostomised subjects and nasal (during velum closure) and oral samples from the non-tracheostomised subjects. Measurements were performed before and after sodium nitrate ingestion (10 mg/kg) and use of antibacterial mouthwash (chlorhexidine 0.2%). RESULTS In tracheostomised subjects oral FE(NO) increased by 90% (p<0.01) while tracheal FE(NO) was not affected 60 minutes after nitrate ingestion. Oral EBC nitrite levels were increased 23-fold at 60 minutes (p<0.001) whereas the nitrite levels in tracheal EBC showed only a minor increase (fourfold, p<0.05). Nitrate was increased the same amount in oral and tracheal EBC at 60 minutes (2.5-fold, p<0.05). In non-tracheostomised subjects oral FE(NO) and EBC nitrite increased after nitrate ingestion and after chlorhexidine mouthwash they approached baseline levels again (p<0.001). Nasal NO, nitrate, and nitrite were not affected by nitrate intake or mouthwash. At baseline, mouthwash with deionised water did not affect nitrite in oral EBC or saliva, whereas significant reductions were seen after antibacterial mouthwash (p<0.05 and p<0.001, respectively). CONCLUSIONS Besides the salivary glands, plasma nitrate is taken up by the lower airways but not the nasal airways. Nitrate levels in EBC are thus influenced by dietary intake. Nitrate is reduced to nitrite by bacterial activity which takes place primarily in the oropharyngeal tract of healthy subjects. Only oropharyngeal nitrite seems to contribute to exhaled NO in non-inflamed airways, and there is also a substantial contribution of nitrite from the oropharyngeal tract during standard collection of EBC.
Paraquat intoxication is a fatal problem. Most paraquat intoxications happen through oral administration. We report a case of death after intravenous paraquat injection. There is little clinical data on parenteral paraquat exposure, and we describe this case and fatal progression. Toxic symptoms and severe organ function impairment developed soon after injection. Treatment with repeated activated charcoal hemoperfusion with pulse steroids, cyclophosphamide, and antioxidants was attempted. The patient died from multiple organ failure 3 days after intoxication. This case indicates that paraquat intoxication via intravenous injection, even in very small amounts, has an extremely poor prognosis.
Methylphenidate is a medication used routinely in the management of attention deficit hyperactivity disorder. We report a case of a prepubertal child who developed unwanted erections after commencing a response-adjusted dosing regimen of sustained release methylphenidate. Despite priapism being a rare adverse reaction associated with methylphenidate, physicians and parents need to be aware as it can have significant long-term complications.
Hypercholesterolemia is associated with impairments in endothelium-dependent vascular relaxations. Paradoxically, endothelial production of nitrogen oxides is increased in early stages of hypercholesterolemia. Prior work has shown that oxidized low density lipoprotein (LDL) has both stimulatory and inhibitory effects on endothelial nitric oxide synthase expression (eNOS) and has focused on lysophosphatidyl choline (LPC) as a component of oxidized LDL which may modulate this effect. Another biologically active component of oxidized LDL is 13-hydroperoxyoctadecadienoic acid (13-HPODE), an oxidized form of linoleic acid. The purpose of this study was to determine the effect of HPODE on the expression of eNOS in bovine aortic endothelial cells (BAECs). Twenty four hour treatment of endothelial cells with HPODE caused a dose-dependent increase in eNOS mRNA levels as assessed by Northern analysis. The time response studies show that HPODE treatment significantly increased eNOS mRNA levels at 12 and 24 h. Concomitant with the increase in eNOS mRNA levels, 20 microM HPODE treatment significantly increased eNOS protein content and enzyme activity. Nuclear run-on studies indicated that the rate of transcription of eNOS gene was significantly elevated 4 h after HPODE treatment when compared to control cultures. Also, actinomycin D studies demonstrated that the half-life of eNOS mRNA was increased from 6 h to 12 h by HPODE treatment. Thus, HPODE-induced up-regulation of eNOS expression is mediated by both transcriptional and posttranscriptional mechanisms. These observations suggest that endothelial cells may attempt to compensate for oxidative injury by increasing expression of eNOS in early stages of hypercholesterolemia.
The hypoxia-inducible factor (HIF) prolyl hydroxylase (PHD) enzymes represent novel targets for the treatment of anemia, ulcerative colitis, and ischemic and metabolic disease inter alia. We have identified a novel small-molecule inhibitor of PHD, 1-(5-chloro-6-(trifluoromethoxy)-1H-benzoimidazol-2-yl)-1H-pyrazole-4-carboxylic acid (JNJ-42041935), through structure-based drug design methods. The pharmacology of JNJ-42041935 was investigated in enzyme, cellular, and whole-animal systems and was compared with other compounds described in the literature as PHD inhibitors. JNJ-42041935, was a potent (pK(I) = 7.3-7.9), 2-oxoglutarate competitive, reversible, and selective inhibitor of PHD enzymes. In addition, JNJ-42041935 was used to compare the effect of selective inhibition of PHD to intermittent, high doses (50 μg/kg i.p.) of an exogenous erythropoietin receptor agonist in an inflammation-induced anemia model in rats. JNJ-42041935 (100 μmol/kg, once a day for 14 days) was effective in reversing inflammation-induced anemia, whereas erythropoietin had no effect. The results demonstrate that JNJ-42041935 is a new pharmacological tool, which can be used to investigate PHD inhibition and demonstrate that PHD inhibitors offer great promise for the treatment of inflammation-induced anemia.
CONTEXT Noninvasive ventilation (NIV) has been associated with lower rates of endotracheal intubation in populations of patients with acute respiratory failure. OBJECTIVE To compare NIV with standard treatment using supplemental oxygen administration to avoid endotracheal intubation in recipients of solid organ transplantation with acute hypoxemic respiratory failure. DESIGN AND SETTING Prospective randomized study conducted at a 14-bed, general intensive care unit of a university hospital. PATIENTS Of 238 patients who underwent solid organ transplantation from December 1995 to October 1997, 51 were treated for acute respiratory failure. Of these, 40 were eligible and 20 were randomized to each group. INTERVENTION Noninvasive ventilation vs standard treatment with supplemental oxygen administration. MAIN OUTCOME MEASURES The need for endotracheal intubation and mechanical ventilation at any time during the study, complications not present on admission, duration of ventilatory assistance, length of hospital stay, and intensive care unit mortality. RESULTS The 2 groups were similar at study entry. Within the first hour of treatment, 14 patients (70%) in the NIV group, and 5 patients (25%) in the standard treatment group improved their ratio of the PaO2 to the fraction of inspired oxygen (FIO2). Over time, a sustained improvement in PaO2 to FIO2 was noted in 12 patients (60%) in the NIV group, and in 5 patients (25%) randomized to standard treatment (P = .03). The use of NIV was associated with a significant reduction in the rate of endotracheal intubation (20% vs 70%; P = .002), rate of fatal complications (20% vs 50%; P = .05), length of stay in the intensive care unit by survivors (mean [SD] days, 5.5 [3] vs 9 [4]; P = .03), and intensive care unit mortality (20% vs 50%; P = .05). Hospital mortality did not differ. CONCLUSIONS These results indicate that transplantation programs should consider NIV in the treatment of selected recipients of transplantation with acute respiratory failure.
Asthma is one of the most common inflammatory diseases characterized by airway hyperresponsiveness, inflammation, and remodeling. Morin, an active ingredient obtained from Moraceae plants, has been demonstrated to have promising anti-inflammatory activities in a range of disorders. However, its impacts on pulmonary diseases, particularly on asthma, have not been clarified. This study was designed to investigate whether morin alleviates airway inflammation in chronic asthma with an emphasis on oxidative stress modulation. In vivo, ovalbumin- (OVA-) sensitized mice were administered with morin or dexamethasone before challenge. Bronchoalveolar lavage fluid (BALF) and lung tissues were obtained to perform cell counts, histological analysis, and enzyme-linked immunosorbent assay. In vitro, human bronchial epithelial cells (BECs) were challenged by tumor necrosis factor alpha (TNF-α). The supernatant was collected for the detection of the proinflammatory proteins, and the cells were collected for reactive oxygen species (ROS)/mitogen-activated protein kinase (MAPK) evaluations. Severe inflammatory responses and remodeling were observed in the airways of the OVA-sensitized mice. Treatment with morin dramatically attenuated the extensive trafficking of inflammatory cells into the BALF and inhibited their infiltration around the respiratory tracts and vessels. Morin administration also significantly suppressed goblet cell hyperplasia and collagen deposition/fibrosis and dose-dependently inhibited the OVA-induced increases in IgE, TNF-α, interleukin- (IL-) 4, IL-13, matrix metalloproteinase-9, and malondialdehyde. In human BECs challenged by TNF-α, the levels of proteins such as eotaxin-1, monocyte chemoattractant protein-1, IL-8 and intercellular adhesion molecule-1, were consistently significantly decreased by morin. Western blotting and the 2',7'-dichlorofluorescein assay revealed that the increases in intracellular ROS and MAPK phosphorylation were abolished by morin, implying that ROS/MAPK signaling contributes to the relief of airway inflammation. Our findings indicate for the first time that morin alleviates airway inflammation in chronic asthma, which probably occurs via the oxidative stress-responsive MAPK pathway, highlighting a novel profile of morin as a potent agent for asthma management.
Hydrogen sulfide (H(2)S) was recently discovered to be synthesized in mammalian tissues by several different enzymes. Numerous studies have shown that H(2)S has vasodilator and antihypertensive effects in the cardiovascular system. However, intracellular mechanisms of the H(2)S-induced vasodilation and its interactions with other endothelium-derived relaxing factors, such as nitric oxide (NO), remain unclear. We investigated whether H(2)S directly regulates endothelial NO synthase (eNOS) activity and NO production in endothelial cells. NaHS, a H(2)S donor, dose-dependently increased NO production in cultured endothelial cells. This effect was abolished by a calcium chelator (BAPTA-AM), but not by the absence of extracellular calcium. The NaHS-induced NO production was partially blocked by inhibitors of ryanodine receptor (dantrolene) or inositol 1,4,5-triphosphate receptor (xestospongin C). NaHS significantly increased intracellular calcium concentrations, and this effect was attenuated by dantrolene or xestospongin C. NaHS induced phosphorylation of eNOS at the activating phosphoserine residue 1179. The NaHS-induced eNOS phosphorylation and NO production were not affected by a PI3K/Akt inhibitor (wortmannin). The data of this study suggest that H(2)S directly acts on endothelial cells to induce eNOS activation and NO production by releasing calcium from the intracellular store in endoplasmic reticulum, which may explain one of mechanisms of its vasodilator function.