Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

4 ( 1 )

2019 ( 3 )

2018 ( 5 )

2017 ( 6 )

Custom range...

Search Results: 1 - 10 of 2666 matches for " JF Vazquez-Jimenez "
All listed articles are free for downloading (OA Articles)
Page 1 /2666
Display every page Item
High oxygen treatment during preparation of children for open-heart surgery leads to a decrease in total antioxidant capacity
CTA Evelo, SLM Coort, NJG Jansen, JF Vazquez-Jimenez, M-C Seghaye
Critical Care , 2001, DOI: 10.1186/cc1008
Abstract: Total trolox equivalents in antioxidant capacity (TEAC) were calculated from the reactivity toward the artificially generated 2,2'-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) radical. To exclude the possibility that TEAC values decrease as a result of haemodilution, we measured the triglyc-eride content using the GPO-trinder (Sigma) reagent in a microtitre-plate spectrophotometric analysis.Total antioxidant capacity was decreased shortly after the onset of surgery in plasma of children (aged 8-14 months) treated for ventricular septal defect (VSD; n = 17) and tetralogy of Fallot (TOF; n = 15). Figure 1 shows a significant (Friedman test; P < 0.05) decrease in both VSD and TOF from time point 1.1 (induction of anaesthesia) to time point 2 (heparin administration before CPB). Decrease in TEAC values can therefore not be a result of haemodilution during CPB. This was confirmed by the fact that total plasma triglyceride values did not decrease between these time points. Shortly after CPB (time point 4) the TEAC values were already significantly (P < 0.05) higher than at time point 3 (10 min after the onset of CPB), and they returned to normal during the 4 h after the operation and remained normal thereafter.We showed a decrease in antioxidant capacity early during the operation, which could not have been caused by haemodilution. The most likely cause appears to be the high oxygen that was given during preparation for CPB. The methodology described here will be useful for study of the influences of different approaches in, for example, oxygen treatment, clamping techniques, temperature treatment and antioxidant supply on the oxidative stress that occurs during open-heart surgery.
Relationship between cardiac troponin I (cTnI) release during cardiac operations and myocardial cell death
JF Vazquez-Jimenez, Ma Qing, B Klosterhalfen, O Liakopoulos, G von Bernuth, BJ Messmer, M-C Seghaye
Critical Care , 2000, DOI: 10.1186/cc722
Abstract: Eighteen young pigs were operated on with standardized cardiopulmonary bypass (CPB). Release of cTnI in the cardiac lymph (CL), coronary sinus (CS), and arterial blood (A) was related to postoperative myocardial cell death by both necrosis and apoptosis. Apoptotic cells were detected by a TUNEL detection kit. Necrotic cells were counted by light microscopy.In all animals, cTnI was significantly released and reached peak values observed simultaneously in A (cTnI, 20.1 ± 2.6 ng/ml) (mean ± SEM), CS (19.5 ± 3.2 ng/ml) and CL (5202 ± 2500 ng/ml). Percentage of total myocardial cell death was 3.1 ± 0.5%, including 1.2 ± 0.35% necrosis and 1.9 ± 0.5% apoptosis. cTnI release during and after CPB did not correlate with the degree of myocardial apoptosis or necrosis.Cardiac operations with CPB are related to myocardial cell damage including myocardial cell death due to both necrosis and apoptosis. As the loss of cTnI is not related to the amount of cell death, our results suggest that increased cardiac myocyte membrane permeability more than cell death is responsible for intraoperative and postoperative cTnI release.
Effect of temperature on leukocyte activation during cardiopulmonary bypass (CPB) and postoperative organ damage
M Qing, M-C Seghaye, JF Vazquez-Jimenez, RG Grabitz, B Klosterhalfen, M Sigler, BJ Messmer, G von Bernuth
Critical Care , 1999, DOI: 10.1186/cc331
Abstract: 18 young pigs were randomly assigned to a T°- group during CPB: normothermia (T° 37°C; n = 6), mild hypothermia (T° 28°C; n = 6) and deep hypothermia (T° 20°C; n = 6). Leukocyte count and plasma levels of tumor necrosis factor (TNFα) were measured before, during and after CPB. At the end of the experimentation (6 h post-CPB), probes of heart, lungs, liver, kidney, and intestine were taken for histological examination.There was a significant fall of leukocyte count at induction of CPB, without any intergroup difference. During and at the end of CPB, leukocyte count was significantly higher in group 37°C as compared with the other groups. At a later stage after CPB, group 20°C showed significantly higher leukocyte count than group 28°C and group 37°C, respectively. The course of neutrophils was similar.TNF-α was not released in group 28°C neither during nor after CPB. By contrast, there was a significant production of TNF-α in groups 37°C and 20°C, the circulating levels being significantly higher in group 37°C. Histological examination showed that the most important tissue damage in terms of interstitial edema and leukostasis in heart, lung, liver, kidney, and small intestine was seen in group 37°C followed by group 20°C while the least important damage was present in group 28°C.CPB-induced postoperative organ damage, probably related to leukocyte activation and TNF-α production, is highest in pigs operated on in normothermia and lowest in those operated on in mild hypothermia.
Myocardial cell damage related to arterial switch operation in neonates with transposition of the great arteries
HH H?vels-Gürich, JF Vazquez-Jimenez, A Silvestri, K Schumacher, S Kreitz, J Duchateau, BJ Messmer, G von Bernuth, M-C Seghaye
Critical Care , 2001, DOI: 10.1186/cc1009
Abstract: Sixty-three neonates (age 2-28 [8.1 ± 4.6] days), who were operated on under combined deep hypothermic (15°C) circulatory arrest and low-flow cardiopulmonary bypass (CPB), were studied. Inclusion criteria were transposition of the great arteries with or without ventricular septal defect (VSD) that was suitable for arterial switch operation (VSD-; n = 53), and if necessary additional VSD closure (VSD+; n = 10). Patients were differentiated clinically into two groups by presence or absence of MD within 24 h after surgery. MD was defined as myocardial ischaemia after coronary reperfusion and/or myocardial hypocontractility as assessed by echocardiography. MD was related to clinical outcome parameters and to perioperative release of cardiac troponin-T (cTnT) and production of interleukin-6 and interleukin-8.MD was observed in 11 patients (17.5%). Two patients died early after surgery from myocardial infarction, and two died late after surgery (6.3%). CPB and cross-clamping, but not deep hypothermic circulatory arrest times, were correlated with MD; MD was more frequent in the VSD+ than in the VSD- group because of longer support times. Coronary status and age at surgery were not related to MD. Patients with MD had more frequently impaired cardiac, respiratory and renal functions. cTnT, interleukin-6 and interleukin-8 were significantly elevated at the end of CPB, and 4 and 24 h after surgery, as compared with preoperative values in both groups. Postoperative cTnT, interleukin-6 and interleukin-8 concentrations were significantly higher in MD patients than in the others. Multivariable analysis of independent risk factors for MD revealed interleukin-6 4 h after surgery to be significant (P = 0.04; odds ratio 1.24 [95% confidence interval 1.01-1.52] per 10 pg/ml). The cutoff point for prediction of MD was set at 500 pg/ml (specificity 95.4%, sensitivity 72.7%).Cardiac operations in neonates induce the production of the proinflammatory cytokines interelukin-6 and interleuki
Is gastric malperfusion and endotoxemia one motor of the systemic inflammatory response syndrome following cardiac surgery?
JP Groetzner, T Graeter, I Lauermann, L Demircan, S Jockenh?vel, JF Vazquez-Jimenez, BJ Messmer, HJ HJ Sch?fers
Critical Care , 1999, DOI: 10.1186/cc318
Abstract: We evaluated one group with low risk for developing SIRS (Group1: coronary artery bypass grafting without CHF) and a high risk group (Group 2: mitral valve surgery with CHF) with 10 patients each for clinical and laboratory signs of SIRS as defined by BONE. Intramucosal gastric pH, endotoxin was detected using a tonometric gastric tube (Baxter Inc.), TNFα and interleukin 6 (IL6) were measured with an ELISA at nine different times pre-, intra- and postoperatively.Groups were similar with regards to age and sex. Cardiac Index was lower in Group 2 (1.7 ± 0.3 l/min/cm3) than in Group 1 (2.8 ± 0.5 l/min/cm3; P < 0.05). In Group 2 the aortic cross clamping time was longer (Group 1: 59.6 ± 15.2 min, Group 2: 42.7 ± 19.4 min) and norepinephrine requirements for maintenance of vascular resistance were higher (8.2 ± 12.6 mg) than in Group 1 (1.7 ± 2 mg; P < 0.05).At the end of CPB gastric pH dropped to 7.33 ± 0.34 in Group 2 whereas the other group remained stable between 7.47 and 7.5 (P < 0.05). Endotoxin levels were significantly elevated and significantly higher in Group 2 (37.2 ± 3.2 pg/ml) than in Group 1 (20.6 ± 3.7 pg/ml; P < 0.05) after aortic cross clamp was opened. In Group 1 only in 1 of 3 patients (33%) with gastric acidosis endotoxin was detected, whereas in Group 2 8/9 patients (88%) endotoxemia occurred.TNFα was elevated in both groups during CPB and significantly higher in Group 2 at aortic declamping (Group 1: 19.6 ± 2.9 pg/ml; Group 2: 39 ± 4.8 pg/ml; P < 0.05) and after protamin application (Group 1: 27.3 ± 4.2 pg/ml; Group 2: 62.8 ± 8.1 pg/ml; P < 0.05). After protamin application IL6 raised postoperatively and was significantly higher in Group 2 (653 ± 75 pg/ml) than in Group 1 (547 ± 439 pg/ml). SIRS occurred more often in Group 2 (9/10) than in Group 1 (6/10) postoperatively. All patients with detected endotoxemia developed SIRS (13/13). (see Figure).SIRS is more common in patients with CHF undergoing CPB than in others. This seems to be related to a dr
The use of moderate hypothermia during cardiac surgery is associated with repression of tumour necrosis factor-α via inhibition of activating protein-1: an experimental study
Ma Qing, Michael W?ltje, Kathrin Schumacher, Magdalena Sokalska, Jaime F Vazquez-Jimenez, Ralf Minkenberg, Marie-Christine Seghaye
Critical Care , 2006, DOI: 10.1186/cc4886
Abstract: Twelve female pigs were randomly subjected to standardized cardiopulmonary bypass with moderate hypothermia or normothermia (temperature 28°C and 37°C, respectively; six pigs in each group). Myocardial probes were sampled from the right ventricle before, during and 6 hours after bypass. We detected mRNA encoding TNF-α by competitive RT-PCR and measured protein levels of TNF-α, inducible nitric oxide synthase and cyclo-oxygenase-2 by Western blotting. Finally, we assessed the activation of NF-κB and activating protein-1, as well as phosphorylation of p38 mitogen-activated protein kinase by electrophoretic mobility shift assay with super shift and/or Western blot.During and after cardiac surgery, animals subjected to hypothermia exhibited lower expression of TNF-α and cyclo-oxygenase-2 but not of inducible nitric oxide synthase. This was associated with lower activation of p38 mitogen-activated protein kinase and of its downstream effector activating protein-1 in hypothermic animals. In contrast, NF-κB activity was no different between groups.These findings indicate that the repression of TNF-α associated with moderate hypothermia during cardiac surgery is associated with inhibition of the mitogen-activated protein kinase p38/activating protein-1 pathway and not with inhibition of NF-κB. The use of moderate hypothermia during cardiac surgery may mitigate the perioperative systemic inflammatory response and its complications.Myocardial damage is an important complication of cardiac surgery involving cardiopulmonary bypass (CPB) [1]. Synthesis of tumour necrosis factor (TNF)-α in the myocardium is thought to play a central role in its pathophysiology [2,3]. Indeed, there is a large body of evidence that, in experimental models, over-expression of TNF-α in the myocardium is related to adverse cardiac effects such as postinfarct remodelling and ventricular dilatation [4], transition from hypertrophic to dilated cardiomyopathy due to apoptosis [5] and impaired postischaemi
Does cardiac surgery in newborn infants compromise blood cell reactivity to endotoxin?
Kathrin Schumacher, Stefanie Korr, Jaime F Vazquez-Jimenez, G?tz von Bernuth, Jean Duchateau, Marie-Christine Seghaye
Critical Care , 2005, DOI: 10.1186/cc3794
Abstract: We investigated 17 newborn infants with transposition of the great arteries undergoing arterial switch operation. Ex vivo production of the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α), of the regulator of the acute-phase response IL-6, and of the natural anti-inflammatory cytokine IL-10 were measured by enzyme-linked immunosorbent assay in the cell culture supernatant after whole blood stimulation by the endotoxin lipopolysaccharide before, 5 and 10 days after the operation. Results were analyzed with respect to postoperative morbidity.The ex vivo production of TNF-α and IL-6 was significantly decreased (P < 0.001 and P < 0.002, respectively), whereas ex vivo production of IL-10 tended to be lower 5 days after the operation in comparison with preoperative values (P < 0.1). Ex vivo production of all cytokines reached preoperative values 10 days after cardiac surgery. Preoperative ex vivo production of IL-6 was inversely correlated with the postoperative oxygenation index 4 hours and 24 hours after the operation (P < 0.02). In contrast, postoperative ex vivo production of cytokines did not correlate with postoperative morbidity.Our results show that cardiac surgery in newborn infants is associated with a transient but significant decrease in the ex vivo production of the pro-inflammatory cytokines TNF-α and IL-6 together with a less pronounced decrease in IL-10 production. This might indicate a transient postoperative anti-inflammatory shift of the cytokine balance in this age group. Our results suggest that higher preoperative ex vivo production of IL-6 is associated with a higher risk for postoperative pulmonary dysfunction.Cardiac surgery is associated with a systemic inflammatory reaction comprising activation of the complement system, stimulation of leukocytes, synthesis of cytokines, and increased interactions between leukocytes and endothelium [1,2]. In children, contact activation, ischemia/reperfusion injury and endotoxin released from the gut [
Prevalence of and risk factors for perioperative arrhythmias in neonates and children after cardiopulmonary bypass: continuous holter monitoring before and for three days after surgery
Lars Grosse-Wortmann, Suzanna Kreitz, Ralph G Grabitz, Jaime F Vazquez-Jimenez, Bruno J Messmer, Goetz von Bernuth, Marie-Christine Seghaye
Journal of Cardiothoracic Surgery , 2010, DOI: 10.1186/1749-8090-5-85
Abstract: 494 consecutive patients, including 96 neonates, were studied with serial 24-hour Holter electrocardiograms before as well as uninterruptedly during the first 72 hours after surgery and prior to discharge.Within 24 hours of surgery 59% of the neonates and 79% of the older children developed arrhythmias. Junctional ectopic tachycardia occurred in 9% of neonates and 5% of non-neonates and ventricular tachycardia in 3% and 15%, respectively.For neonates, male sex and longer cross-clamping time independently increased the risk for arrhythmias (odds ratios 2.83 and 1.96/minute, respectively). Ventricular septal defect repair was a strong risk factor for junctional ectopic tachycardia in neonates and in older children (odds ratios 18.8 and 3.69, respectively). For infants and children, older age (odds ratio 1.01/month) and closure of atrial septal defects (odds ratio 2.68) predisposed to arrhythmias of any type.We present the largest cohort of neonates, infants and children that has been prospectively studied for the occurrence of arrhythmias after cardiac surgery. Postoperative arrhythmias are a frequent and transient phenomenon after cardiopulmonary bypass, provoked both by mechanical irritation of the conduction system and by humoral factors.Arrhythmias are common in the early postoperative period after cardiac surgery for congenital heart disease[1-3]. Although transient and treatable in most cases, they are the cause of substantial morbidity and mortality during a vulnerable phase of hemodynamic instability.Thus far the overall incidence and risk factors of transient early postoperative arrhythmias in neonates and children undergoing cardiac surgery have only been addressed in a limited number of studies,[3,4] each using overhead bedside monitoring. While this method is sensitive enough for sustained and hemodynamically significant arrhythmias, shorter or more subtle rhythm disorders that may still reflect electrical instability of the myocyctes and a propensity to d
Neuroendoscopy in Epilepsy Surgery  [PDF]
Oscar Humberto Jimenez-Vazquez, Norma Nagore
World Journal of Neuroscience (WJNS) , 2016, DOI: 10.4236/wjns.2016.62014
Abstract: Epilepsy surgery has constantly evolved in various fields of knowledge. Surgical criteria have shifted from standard procedures to individualized forms of treatment, depending on physiological tests and specific imagenology findings in an individual patient. New instruments and applications based upon older instruments have been described in the treatment of epilepsy surgery, including the use of endoscopes. Frequent indications of neuroendoscopy in epilepsy surgery have been mostly to assist in open procedures, particularly when fluid-filled spaces are present within the surgical field, such as cystic parasites, tumors, arachnoid, or other types of cysts. Other indications certainly include cases of temporal lobe epilepsy, where ventricular exploration precedes intraventricular electrode placing as a tool to localize epileptogenic zones. Although described several years ago, there has been a recent trend in performing endoscopy-assisted section of the corpus-callosum in patients with generalized seizures. As neurosurgical instruments and techniques continue their progress, endoscopy will be included more frequently as part of the armamentarium in epilepsy surgery.
Powering AGNs with super-critical black holes
A. Avgoustidis,R. Jimenez,L. Alvarez-Gaume,M. A. Vazquez-Mozo
Physics , 2009,
Abstract: We propose a novel mechanism for powering the central engines of Active Galactic Nuclei through super-critical (type II) black hole collapse. In this picture, ~$10^3 M_\odot$ of material collapsing at relativistic speeds can trigger a gravitational shock, which can eject a large percentage of the collapsing matter at relativistic speeds, leaving behind a "light" black hole. In the presence of a poloidal magnetic field, the plasma collimates along two jets, and the associated electron synchrotron radiation can easily account for the observed radio luminosities, sizes and durations of AGN jets. For Lorentz factors of order 100 and magnetic fields of a few hundred $\mu G$, synchrotron electrons can shine for $10^6$ yrs, producing jets of sizes of order 100 kpc. This mechanism may also be relevant for Gamma Ray Bursts and, in the absence of magnetic field, supernova explosions.
Page 1 /2666
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.