L'arrêt cardiaque: quelle réalité et quelle formation pour le praticien [Heart arrest: which reality and which training for the practitioner?]

Sudden death related to out-of hospital cardiac arrest is an important cause of mortality, which is mainly caused by ventricular fibrillation, a potentially reversible condition. The prognosis of out-of-hospital cardiac arrest remains dismal despite well developed emergency medical services. Witnessed arrest, ventricular fibrillation as the initial arrhythmia, cardiopulmonary resuscitation and early defibrillation are systematically associated with better survival. Key interventions must therefore be enforced to improve survival from out-of-hospital cardiac, introducing the concept of a "chain of survivals". The aim of the present article, which is illustrated by local results, is to review this important public health issue, to emphasize the role of the general practitioner in the chain of survival, and to promote education and training of basic and advanced life support.

A downstream mediator in the growth repression limb of the jasmonate pathway.

Wounding plant tissues initiates large-scale changes in transcription coupled to growth arrest, allowing resource diversion for defense. These processes are mediated in large part by the potent lipid regulator jasmonic acid (JA). Genes selected from a list of wound-inducible transcripts regulated by the jasmonate pathway were overexpressed in Arabidopsis thaliana, and the transgenic plants were then assayed for sensitivity to methyl jasmonate (MeJA). When grown in the presence of MeJA, the roots of plants overexpressing a gene of unknown function were longer than those of wild-type plants. When transcript levels for this gene, which we named JASMONATE-ASSOCIATED1 (JAS1), were reduced by RNA interference, the plants showed increased sensitivity to MeJA and growth was inhibited. These gain- and loss-of-function assays suggest that this gene acts as a repressor of JA-inhibited growth. An alternative transcript from the gene encoding a second protein isoform with a longer C terminus failed to repress jasmonate sensitivity. This identified a conserved C-terminal sequence in JAS1 and related genes, all of which also contain Zim motifs and many of which are jasmonate-regulated. Both forms of JAS1 were found to localize to the nucleus in transient expression assays. Physiological tests of growth responses after wounding were consistent with the fact that JAS1 is a repressor of JA-regulated growth retardation.

Pacemaker therapy in patients with neurally mediated syncope and documented asystole: Third International Study on Syncope of Uncertain Etiology (ISSUE-3): a randomized trial.

BACKGROUND: The efficacy of cardiac pacing for prevention of syncopal recurrences in patients with neurally mediated syncope is controversial. We wanted to determine whether pacing therapy reduces syncopal recurrences in patients with severe asystolic neurally mediated syncope. METHODS AND RESULTS: Double-blind, randomized placebo-controlled study conducted in 29 centers in the Third International Study on Syncope of Uncertain Etiology (ISSUE-3) trial. Patients were ≥40 years, had experienced ≥3 syncopal episodes in the previous 2 years. Initially, 511 patients, received an implantable loop recorder; 89 of these had documentation of syncope with ≥3 s asystole or ≥6 s asystole without syncope within 12 ± 10 months and met criteria for pacemaker implantation; 77 of 89 patients were randomly assigned to dual-chamber pacing with rate drop response or to sensing only. The data were analyzed on intention-to-treat principle. There was syncope recurrence during follow-up in 27 patients, 19 of whom had been assigned to pacemaker OFF and 8 to pacemaker ON. The 2-year estimated syncope recurrence rate was 57% (95% CI, 40-74) with pacemaker OFF and 25% (95% CI, 13-45) with pacemaker ON (log rank: P=0.039 at the threshold of statistical significance of 0.04). The risk of recurrence was reduced by 57% (95% CI, 4-81). Five patients had procedural complications: lead dislodgment in 4 requiring correction and subclavian vein thrombosis in 1 patient. CONCLUSIONS: Dual-chamber permanent pacing is effective in reducing recurrence of syncope in patients ≥40 years with severe asystolic neurally mediated syncope. The observed 32% absolute and 57% relative reduction in syncope recurrence support this invasive treatment for the relatively benign neurally mediated syncope. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00359203.

FANCD2 binds MCM proteins and controls replisome function upon activation of s phase checkpoint signaling.

Proteins disabled in Fanconi anemia (FA) are necessary for the maintenance of genome stability during cell proliferation. Upon replication stress signaling by ATR, the FA core complex monoubiquitinates FANCD2 and FANCI in order to activate DNA repair. Here, we identified FANCD2 and FANCI in a proteomic screen of replisome-associated factors bound to nascent DNA in response to replication arrest. We found that FANCD2 can interact directly with minichromosome maintenance (MCM) proteins. ATR signaling promoted the transient association of endogenous FANCD2 with the MCM2-MCM7 replicative helicase independently of FANCD2 monoubiquitination. FANCD2 was necessary for human primary cells to restrain DNA synthesis in the presence of a reduced pool of nucleotides and prevented the accumulation of single-stranded DNA, the induction of p21, and the entry of cells into senescence. These data reveal that FANCD2 is an effector of ATR signaling implicated in a general replisome surveillance mechanism that is necessary for sustaining cell proliferation and attenuating carcinogenesis.

Diagnosis and management of blunt great vessel trauma.

Traditionally, thoracic aortic rupture, suspected after blunt thoracic trauma, is characterized by a chest radiograph showing a widened mediastinum. The diagnostic machinery consecutively activated still depends heavily on the pressure as additional traumatic lesions. A patient with additional cranio-cerebral trauma would typically undergo contrast-enhanced computed tomography or magnetic resonance imaging of head, chest, and other regions. In a number of patients these analyses would confirm the presence of blood in the mediastinum without formal proof of an aortic disruption. This is because mediastinal hematomas may be caused not only by an aortic rupture, but also by numerous other blood sources including fractures of the spine and other macro- and microvascular lesions providing similar images. Therefore, aortic angiography became our preferred diagnostic tool to identify or rule out acute traumatic lesions of not only the aorta but with great vessels. However recently, a number of traumatic aortic transsections have been identified by transoesophageal echocardiography (TEE). TEE has the additional advantage of being a bed-side procedure providing additional information about cardiac function. The latter analysis allows for identification and quantification of cardiac contusions, post-traumatic myocardial infarctions, and valvar lesions which are of prime importance to develop an adequate surgical strategy and to assess the risk of the numerous emergency procedures required in patients with polytrauma. The standard approach for repair of isthmic aortic rupture is through a lateral thoracotomy. Distal and proximal control of the aorta can be achieved in a substantial number of cases before complete aortic rupture occurs and a higher proportion of direct suture repair can be achieved under such circumstances. Most proximal descending aortic procedures are performed without cardiopulmonary bypass (clamp and go) but paraplegia may occur before, during, or after the procedure. Ascending aortic lesions and disruption of the aortic arch, the supra-aortic vessels, the main pulmonary arteries, the great veins as well as cardiac lesions are best approached through a sternotomy, which may have to be extended. Cardiopulmonary bypass allowing for deep hypothermia and circulatory arrest is often required and carries its own complications. It is not clear whether the increasing proportion of ascending aortic and cardiac lesions which are observed nowadays are due to a change in trauma mechanics (i.e., speed limits, seat belts, air-bags), an improvement of the diagnostic tools or both.

Épidémiologie et physiopathologie de la rétinopathie du prématuré [Epidemiology and pathophysiology of retinopathy of prematurity].

Retinopathy of prematurity (ROP) is a major cause of visual impairment in premature infants. It is characterized by an arrest in normal retinal vascular development associated with microvascular degeneration, followed by an abnormal hypoxiainduced neovascularization. Recent studies point out that ROP is a multifactorial disease, implicating both oxygen-dependent and oxygen-independent mechanisms. Oxygen-dependent factors leading to microvascular degeneration include generation of reactive oxygen species and suppression of specific oxygen-regulated vascular survival factors, such as vascular endothelial growth factor (VEGF) and erythropoietin. The other major mechanism for the initial capillary loss is oxygen-independent and implicates a deficit in growth factor IGF-1/IGFBP3. The proliferative, second phase of ROP is triggered by increases in vascular growth factors concentrations, in an attempt to compensate for the hypoxic retina. Novel signaling pathways for vascular repair, implicating both metabolite signaling and inflammatory lipids signaling, represent new therapeutic avenues for ROP.

Ictal bradycardia and asystole: an uncommon cause of syncope.

We report on two patients with recurrent syncope secondary to ictal bradyarrhythmias, triggered by partial epileptic seizures with atypical, stereotyped auras. Ictal bradyarrhythmias are potentially lethal, and likely originate from the involvement of limbic autonomic regions. The appropriate treatment is double-headed, including an antiepileptic drug and the implantation of a pacemaker.

Early EEG correlates of neuronal injury after brain anoxia.

OBJECTIVES: EEG and serum neuron-specific enolase (NSE) are used for outcome prognostication in patients with postanoxic coma; however, it is unclear if EEG abnormalities reflect transient neuronal dysfunction or neuronal death. To assess this question, EEG abnormalities were correlated with NSE. Moreover, NSE cutoff values and hypothermic EEG features related with poor outcome were explored.¦METHODS: In a prospective cohort of 61 adults treated with therapeutic hypothermia (TH) after cardiac arrest (CA), multichannel EEG recorded during TH was assessed for background reactivity and continuity, presence of epileptiform transients, and correlated with serum NSE collected at 24-48 hours after CA. Demographic, clinical, and functional outcome data (at 3 months) were collected and integrated in the analyses.¦RESULTS: In-hospital mortality was 41%, and 82% of survivors had good neurologic outcome at 3 months. Serum NSE and EEG findings were strongly correlated (Spearman rho = 0.45; p < 0.001). Median NSE peak values were higher in patients with unreactive EEG background (p < 0.001) and discontinuous patterns (p = 0.001). While all subjects with nonreactive EEG died, 5 survivors (3 with good outcome) had NSE levels >33 μg/L.¦CONCLUSION: The correlation between EEG during TH and serum NSE levels supports the hypothesis that early EEG alterations reflect permanent neuronal damage. Furthermore, this study confirms that absent EEG background reactivity and presence of epileptiform transients are robust predictors of poor outcome after CA, and that survival with good neurologic recovery is possible despite serum NSE levels> 33 μg/L. This underscores the importance of multimodal assessments in this setting.

Efficacy and safety of a phospholipid emulsion (GR270773) in Gram-negative severe sepsis: results of a phase II multicenter, randomized, placebo-controlled, dose-finding clinical trial.

OBJECTIVE: To assess the survival benefit and safety profile of low-dose (850 mg/kg) and high-dose (1350 mg/kg) phospholipid emulsion vs. placebo administered as a continuous 3-day infusion in patients with confirmed or suspected Gram-negative severe sepsis. Preclinical and ex vivo studies show that lipoproteins bind and neutralize endotoxin, and experimental animal studies demonstrate protection from septic death when lipoproteins are administered. Endotoxin neutralization correlates with the amount of phospholipid in the lipoprotein particles. DESIGN: A three-arm, randomized, blinded, placebo-controlled trial. SETTING: Conducted at 235 centers worldwide between September 2004 and April 2006. PATIENTS: A total of 1379 patients participated in the study, 598 patients received low-dose phospholipid emulsion, and 599 patients received placebo. The high-dose phospholipid emulsion arm was stopped, on the recommendation of the Independent Data Monitoring Committee, due to an increase in life-threatening serious adverse events at the fourth interim analysis and included 182 patients. MEASUREMENTS AND MAIN RESULTS: A 28-day all-cause mortality and new-onset organ failure. There was no significant treatment benefit for low- or high-dose phospholipid emulsion vs. placebo for 28-day all-cause mortality, with rates of 25.8% (p = .329), 31.3% (p = .879), and 26.9%, respectively. The rate of new-onset organ failure was not statistically different among groups at 26.3%, 31.3%, 20.4% with low- and high-dose phospholipid emulsion, and placebo, respectively (one-sided p = .992, low vs. placebo; p = .999, high vs. placebo). Of the subjects treated, 45% had microbiologically confirmed Gram-negative infections. Maximal changes in mean hemoglobin levels were reached on day 10 (-1.04 g/dL) and day 5 (-1.36 g/dL) with low- and high-dose phospholipid emulsion, respectively, and on day 14 (-0.82 g/dL) with placebo. CONCLUSIONS: Treatment with phospholipid emulsion did not reduce 28-day all-cause mortality, or reduce the onset of new organ failure in patients with suspected or confirmed Gram-negative severe sepsis.

An unusual case of accidental poisoning: fatal methadone inhalation.

In this report, the authors present a case of unusual, accidental methadone intoxication in a 40-year-old man, who had inhaled methadone powder. The drug dealer was a pharmacy technician; methadone had been stolen from a pharmacy and sold as cocaine. After having inhaled methadone powder, he suffered cardiopulmonary arrest. He was admitted to hospital where he died after 24 h of intensive care. The autopsy revealed congestion of internal organs and cerebral and pulmonary edema. Microscopically, the heart showed no changes. The toxicological analyses performed on blood and urine taken at the hospital revealed methadone, cannabinoids, and ethanol. The blood methadone concentration was 290 μg/L. The urine methadone concentration was 160 μg/L. Midazolam and lidocaine, which were administered to the patient at the hospital, were also detected in the blood. The cause of death was determined to be methadone intoxication. The literature has been reviewed and discussed. To date, and to our knowledge, only very few cases of accidental death resulting from methadone inhalation have been described up to the case presented herein.

Extracellular deposition of matrilin-2 controls the timing of the myogenic program during muscle regeneration.

Here, we identify a role for the matrilin-2 (Matn2) extracellular matrix protein in controlling the early stages of myogenic differentiation. We observed Matn2 deposition around proliferating, differentiating and fusing myoblasts in culture and during muscle regeneration in vivo. Silencing of Matn2 delayed the expression of the Cdk inhibitor p21 and of the myogenic genes Nfix, MyoD and Myog, explaining the retarded cell cycle exit and myoblast differentiation. Rescue of Matn2 expression restored differentiation and the expression of p21 and of the myogenic genes. TGF-β1 inhibited myogenic differentiation at least in part by repressing Matn2 expression, which inhibited the onset of a positive-feedback loop whereby Matn2 and Nfix activate the expression of one another and activate myoblast differentiation. In vivo, myoblast cell cycle arrest and muscle regeneration was delayed in Matn2(-/-) relative to wild-type mice. The expression levels of Trf3 and myogenic genes were robustly reduced in Matn2(-/-) fetal limbs and in differentiating primary myoblast cultures, establishing Matn2 as a key modulator of the regulatory cascade that initiates terminal myogenic differentiation. Our data thus identify Matn2 as a crucial component of a genetic switch that modulates the onset of tissue repair.

Effects of verapamil and ryanodine on activity of the embryonic chick heart during anoxia and reoxygenation.

Perturbations of the trans-sarcolemmal and sarcoplasmic Ca2+ transport contribute to the abnormal myocardial activity provoked by anoxia and reoxygenation. Whether Ca2+ pools of the extracellular compartment and sarcoplasmic reticulum (SR) are involved to the same extent in the dysfunction of the anoxic-reoxygenated immature heart has not been investigated. Spontaneously contracting hearts isolated from 4-day-old chick embryos were submitted to repeated anoxia (1 min) followed by reoxygenation (5 min). Heart rate, atrioventricular propagation velocity, ventricular shortening, velocities of contraction and relaxation, and incidence of arrhythmias were studied, recorded continuously. Addition of verapamil (10 nM), which blocks selectively sarcolemmal L-type Ca2+ channels, was expected to protect against excessive entry of extracellular Ca2+, whereas addition of ryanodine (10 nM), which opens the SR Ca2+ release channel, was expected to increase cytosolic Ca2+ concentration. Verapamil (a) had no dromotropic effect by contrast to adult heart, (b) attenuated ventricular contracture induced by repeated anoxia, (c) shortened cardioplegia induced by reoxygenation, and (d) had remarkable antiarrhythmic properties during reoxygenation specially. On the other hand, ryanodine potentiated markedly arrhythmias both during anoxia and at reoxygenation. Thus despite its immaturity, the SR seems to be functional early in the developing chick heart and involved in the reversible dysfunction induced by anoxia-reoxygenation. Moreover, Ca2+ entry through L-type channels appears to worsen arrhythmias especially during reoxygenation. These findings show that the Ca2+-handling systems involved in irregular activity in immature heart, such as the embryonic chick heart, may differ from those in the adult.

A Comparative Policy Analysis of Seat Belt Laws, RB37-013, 2014

This analysis examined data from a variety of sources to estimate the benefit of enhancing Iowa’s current law to require all passengers to use seat belts. In addition to assessing Iowans’ opinions about changing the law, a literature review, a legislative policy review, and analysis of Iowa crash data were completed. Currently 28 states enforce seat belt laws for all passengers. Belted passengers riding with an unbelted passenger are 2 to 5 times more likely to suffer fatal injuries in a crash relative to when all occupants are using seat belts. Iowans are highly compliant (90%-94%) with the current seat belt law for front seat occupants. Of more than 1000 Iowans surveyed, 85% said they always use a seat belt when riding in the front seat, but only 36% always do so when they ride in the back seat. The most common reasons given for not using seat belts in the back seat are forgetting to buckle up and because it is not the law. Iowans widely support strengthening Iowa’s seat belt law — 62% said Iowa law should require all rear seat passengers to use seat belts. Four out of five respondents said they would use seat belts more often when sitting in the rear seat if it was the law. It is estimated rear seat fatalities would decrease about 48%, from 13 to 7 fatalities annually, if an all-passenger law was implemented in Iowa.

Phosphorylation by casein kinase 2 facilitates rRNA gene transcription by promoting dissociation of TIF-IA from elongating RNA polymerase I.

The protein kinase casein kinase 2 (CK2) phosphorylates different components of the RNA polymerase I (Pol I) transcription machinery and exerts a positive effect on rRNA gene (rDNA) transcription. Here we show that CK2 phosphorylates the transcription initiation factor TIF-IA at serines 170 and 172 (Ser170/172), and this phosphorylation triggers the release of TIF-IA from Pol I after transcription initiation. Inhibition of Ser170/172 phosphorylation or covalent tethering of TIF-IA to the RPA43 subunit of Pol I inhibits rDNA transcription, leading to perturbation of nucleolar structure and cell cycle arrest. Fluorescence recovery after photobleaching and chromatin immunoprecipitation experiments demonstrate that dissociation of TIF-IA from Pol I is a prerequisite for proper transcription elongation. In support of phosphorylation of TIF-IA switching from the initiation into the elongation phase, dephosphorylation of Ser170/172 by FCP1 facilitates the reassociation of TIF-IA with Pol I, allowing a new round of rDNA transcription. The results reveal a mechanism by which the functional interplay between CK2 and FCP1 sustains multiple rounds of Pol I transcription.

Inhibition of bicarbonate transport protects embryonic heart against reoxygenation-induced dysfunction.

It has not been well established whether the mechanisms participating in pH regulation in the anoxic-reoxygenated developing myocardium resemble those operating in the adult. We have specially examined the importance of Na+/H+ exchange (NHE) and HCO3-dependent transports in cardiac activity after changes in extracellular pH (pHo). Spontaneously contracting hearts isolated from 4-day-old chick embryos were submitted to single or repeated anoxia (1 min) followed by reoxygenation (10 min). The chronotropic, dromotropic and inotropic responses of the hearts were determined in standard HCO3- buffer at pHo 7.4 and at pHo 6.5 (hypercapnic acidosis). In distinct experiments, acidotic anoxia preceded reoxygenation at pHo 7.4. NHE was blocked with amiloride derivative HMA (1 micro mol/l) and HCO3-dependent transports were inactivated by replacement of HCO3 or blockade with stilbene derivative DIDS (100 micro mol/l). Anoxia caused transient tachycardia, depressed mechanical function and induced contracture. Reoxygenation temporarily provoked cardiac arrest, atrio-ventricular (AV) block, arrhythmias and depression of contractility. Addition of DIDS or substitution of HCO3 at pHo 7.4 had the same effects as acidosis per se, i.e. shortened contractile activity and increased incidence of arrhythmias during anoxia, prolonged cardioplegia and provoked arrhythmias at reoxygenation. Under anoxia at pHo 6.5/reoxygenation at pHo 7.4, cardioplegia, AV block and arrhythmias were all markedly prolonged. Interestingly, in the latter protocol, DIDS suppressed AV block and arrhythmias during reoxygenation, whereas HMA had no effect. Thus, intracellular pH regulation in the anoxic-reoxygenated embryonic heart appears to depend predominantly on HCO3 availability and transport. Furthermore, pharmacological inhibition of anion transport can protect against reoxygenation-induced dysfunction.