86 results on '"Chamoun R"'
Search Results
2. Image Guided Epilepsy Surgery
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Comair, Y. G., Chamoun, R. B., Lozano, Andres M., editor, Gildenberg, Philip L., editor, and Tasker, Ronald R., editor
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- 2009
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3. From soil to lab: Utilization of clays as catalyst supports in hydrogen generation from sodium borohydride fuel
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Chamoun, R., Demirci, B., Cornu, D., Zaatar, Y., Khoury, R., Khoury, A., and Miele, P.
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- 2011
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4. Co-αAl 2O 3-Cu as shaped catalyst in NaBH 4 hydrolysis
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Chamoun, R., Demirci, U.B., Zaatar, Y., Khoury, A., and Miele, P.
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- 2010
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5. Cobalt-supported alumina as catalytic film prepared by electrophoretic deposition for hydrogen release applications
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Chamoun, R., Demirci, U.B., Cornu, D., Zaatar, Y., Khoury, A., Khoury, R., and Miele, P.
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- 2010
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6. Rôle du récepteur minéralocorticoïde dans la physiologie du cortex surrénalien et le développement d’adénomes produisant de l’aldostérone (APA)
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Fayad, M., El Zein, R.M., Faedda, N., Fedlaoui, B., Chamoun, R., Rezvanisanijouybari, P., Boulkroun, S., Fernandes-Rosa, F.L., Giscos-Douriez, I., Davies, E., and Zennaro, M.C.
- Abstract
Les surrénales avec un adénome produisant l’aldostérone (APA) présentent une augmentation de la nodulation et un remodelage important. Le récepteur minéralocorticoïde (MR) lie l’aldostérone et est exprimé dans la zone glomérulée (ZG) de la corticosurrénale et dans les APA. Dans d’autres tissus, le MR est impliqué dans le remodelage et la fibrose tissulaire. Nous avons donc émis l’hypothèse que l’aldostérone pourrait être impliqué dans la physiopathologie de l’APA à travers le MR par un mécanisme autocrine/paracrine.
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- 2024
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7. Role of temozolomide in spinal cord low grade astrocytomas: results in two paediatric patients
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Chamoun, R. B., Alaraj, A. M., Al Kutoubi, A. O., Abboud, M. R., and Haddad, G. F.
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- 2006
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8. Spontaneous subdural haematoma in anabolic steroids dependent weight lifters: reports of two cases and review of literature
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Alaraj, A. M., Chamoun, R. B., Dahdaleh, N. S., Haddad, G. F., and Comair, Y. G.
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- 2005
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9. The Effect of Debulking Surgery on Brainstem Dosimetry and Toxicity for Large Vestibular Schwannomas Treated with Fractionated Stereotactic Radiation Therapy
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Mallory, M., primary, Kauweloa, K., additional, Staecker, H., additional, Camarata, P., additional, Chamoun, R., additional, Badkul, R., additional, Tennapel, M.J., additional, and Wang, F., additional
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- 2018
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10. Fractionated Stereotactic Radiation Therapy for Large Vestibular Schwannomas
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Mallory, M., primary, Wang, F., additional, Badkul, R.K., additional, Tennapel, M.J., additional, Camarata, P., additional, Staecker, H., additional, and Chamoun, R., additional
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- 2017
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11. Sodium borohydride hydrolysis : Development of efficient and cheap catalysts for room temperature hydrogen release
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Ouardia, Akdim, Demirci, Umit B., Miele, Philippe, Chamoun, R., Rachiero, G.P., Cavaliere, Sara, Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), and FALQUE, Philippe
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[CHIM] Chemical Sciences ,[CHIM]Chemical Sciences ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 2011
12. Cobalt in hydrolysis of sodium borohydride
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Demirci, Umit B., Akdim, O., Chamoun, R., Cavaliere, S., Miele, Philippe, Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), and FALQUE, Philippe
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[CHIM] Chemical Sciences ,[CHIM]Chemical Sciences ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 2011
13. Metal nanoparticles in hydrolytic dehydrogenation of boron-based complex hydrides
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Demirci, Umit B., Miele, Philippe, Chamoun, R., Akdim, O., Rachiero, G.P., Cavaliere, S., Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), and FALQUE, Philippe
- Subjects
[CHIM] Chemical Sciences ,[CHIM]Chemical Sciences ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 2011
14. α-Na2Ni2Fe(PO4)3: a dual positive/negative electrode material for sodium ion batteries
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Essehli, R., primary, Belharouak, I., additional, Ben Yahia, H., additional, Chamoun, R., additional, Orayech, B., additional, El Bali, B., additional, Bouziane, K., additional, Zhou, X. L., additional, and Zhou, Z., additional
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- 2015
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15. Ammonia Borane and Sodium Borohydride: Boron Hydrides as Hydrogen Storage Materials Intended to Specific and Different Applications
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Demirci, U. B., Hannauer, J., Chamoun, R., Miele, P., Grube, Thomas, and Stolten, Detlef
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- 2010
16. Nervus intermedius meningioma
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Rodgers, B, primary, Chamoun, R, additional, Newell, K, additional, and Lin, J, additional
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- 2014
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17. Co-αAl2O3-Cu as shaped catalyst in NaBH4 hydrolysis
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Chamoun, R., primary, Demirci, U.B., additional, Zaatar, Y., additional, Khoury, A., additional, and Miele, P., additional
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- 2010
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18. Sodium Borohydride Hydrolysis as Hydrogen Generator: Issues, State of the Art and Applicability Upstream from a Fuel Cell
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Demirci, U. B., primary, Akdim, O., additional, Andrieux, J., additional, Hannauer, J., additional, Chamoun, R., additional, and Miele, P., additional
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- 2010
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19. Spontaneous subdural haematoma in anabolic steroids dependent weight lifters: reports of two cases and review of literature
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Alaraj, A. M., primary, Chamoun, R. B., additional, Dahdaleh, N. S., additional, Haddad, G. F., additional, and Comair, Y. G., additional
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- 2004
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20. Co-αAl2O3-Cu as shaped catalyst in NaBH4 hydrolysis
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Chamoun, R., Demirci, U.B., Zaatar, Y., Khoury, A., and Miele, P.
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COBALT compounds , *METAL catalysts , *HYDROLYSIS , *SODIUM borohydride , *ELECTROPHORETIC deposition , *THIN films , *CHEMICAL kinetics - Abstract
Abstract: A study about catalytic films of Co-supported-over-αAl2O3 fabricated by electrophoretic deposition (EPD) is reported, the as-prepared shaped catalysts being intended to catalyze NaBH4 hydrolysis. Co-αAl2O3 supported over Cu substrate can be prepared by a 2-step route: (i) preparation of the supported catalyst Co-αAl2O3 (in powder form) by wet impregnation of CoCl2 over αAl2O3, followed by a reduction, and (ii) fabrication of Co-αAl2O3-Cu (thin film over Cu) by EPD. Both types of catalysts, whatever their form, are highly efficient in hydrolyzing NaBH4, conversions of 100% and HGRs of tens of mL(H2) min−1 being achieved at 60–80 °C. The Co-αAl2O3-Cu catalysts are even more reactive than the Co-αAl2O3 catalysts because the surface of the former materials becomes much more acid than that of the latter ones in the course of the EPD process. The respective rate laws and reaction kinetics have been determined. Independently on the catalyst form, apparent activation energies of about 52 kJ mol−1 and positive reaction orders versus the initial NaBH4 concentration (i.e. 0.3–0.7) were calculated, suggesting that the EPD does not affect the reaction mechanisms. Besides, it is showed that the hydrolysis is really catalytic as well as typical of a heterogeneous process. For example, an apparent reaction order versus the Co content of 0.9 was calculated. All of these results among others are reported and discussed in the present article. [Copyright &y& Elsevier]
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- 2010
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21. Is SSRI use a risk factor for intracranial hemorrhage after craniotomy for tumor resection?
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Estes BJ, Masri AR, and Chamoun R
- Abstract
Introduction: Prior studies have identified SSRI use as a risk factor for certain adverse bleeding outcomes. However, the risk of significant bleeding from perioperative SSRI use after brain tumor resection remains largely undetermined. This study evaluates if patients taking SSRIs perioperatively have a higher risk of intracranial hemorrhage (ICH) following elective craniotomy for tumor resection., Methods: Researchers reviewed electronic medical records of patients age 18 and older, who received elective craniotomy for tumor resection between 2010 and 2019. Data collection included subject demographics and relevant medical history. We compared intracranial hemorrhage rates and risks between perioperative SSRI-use cohorts., Results: Of 1,061 patients, 796 (75%) did not use SSRIs perioperatively while 265 (25%) used SSRIs perioperatively. Among those using perioperative SSRIs, 8 patients (3.0%) experienced an ICH within 1 week and 11 patients (4.2%) had an ICH within 1 month. Similarly, for those who stopped SSRI use perioperatively, we found 31 patients (3.9%) experienced an ICH within 1 week and 40 patients (5.0%) had an ICH within 1 month. Using logistic regression analysis, the relative risk for perioperative SSRI-use and ICH was statistically non-significant at 0.692 (95% CI: 0.260 - 1.839, p = 0.460)., Conclusions: Based on our results, perioperative SSRI use does not appear to result in an increased risk of bleeding within 1 week or month of craniotomy for tumor resection. These results remained consistent when controlled for several additional bleeding comorbidities and demographics between cohorts., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)
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- 2024
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22. Atrial fibrosis by cardiac MRI is a correlate for atrial stiffness in patients with atrial fibrillation.
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Lamy J, Taoutel R, Chamoun R, Akar J, Niederer S, Mojibian H, Huber S, Baldassarre LA, Meadows J, and Peters DC
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- Humans, Contrast Media, Predictive Value of Tests, Gadolinium, Heart Atria, Magnetic Resonance Imaging, Fibrosis, Atrial Fibrillation diagnostic imaging, Catheter Ablation
- Abstract
A relationship between left atrial strain and pressure has been demonstrated in many studies, but not in an atrial fibrillation (AF) cohort. In this work, we hypothesized that elevated left atrial (LA) tissue fibrosis might mediate and confound the LA strain vs. pressure relationship, resulting instead in a relationship between LA fibrosis and stiffness index (mean LA pressure/LA reservoir strain). Sixty-seven patients with AF underwent a standard cardiac MR exam including long-axis cine views (2 and 4-ch) and a free-breathing high resolution three-dimensional late gadolinium enhancement (LGE) of the atrium (N = 41), within 30 days prior to AF ablation, at which procedure invasive mean left atrial pressure (LAP) was measured. LV and LA Volumes, EF, and comprehensive analysis of LA strains (strain and strain rates and strain timings during the atrial reservoir, conduit and active, i.e. active atrial contraction, phases) were measured and LA fibrosis content (LGE (ml)) was assessed from 3D LGE volumes. LA LGE was well correlated to atrial stiffness index overall (R = 0.59, p < 0.001), and among patient subgroups. Pressure was only correlated to maximal LA volume (R = 0.32) and the time to peak reservoir strain rate (R = 0.32) (both p < 0.01), among all functional measurements. LA reservoir strain was strongly correlated with LAEF (R = 0.95, p < 0.001) and LA minimum volume (r = 0.82, p < 0.001). In our AF cohort, pressure is correlated to maximum LA volume and time to peak reservoir strain. LA pressure/ LA reservoir strain, a metric of stiffness, correlates with LA fibrosis (LA LGE), reflecting Hook's Law., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)
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- 2024
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23. Atrial Fibrosis by cardiac MRI is a correlate for atrial stiffness in patients with atrial fibrillation.
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Lamy J, Taoutel R, Chamoun R, Akar J, Niederer S, Mojibian H, Huber S, Baldassarre LA, Meadows J, and Peters DC
- Abstract
Aims: A relationship between left atrial strain and pressure has been demonstrated in many studies, but not in an atrial fibrillation (AF) cohort. In this work, we hypothesized that elevated left atrial (LA) tissue fibrosis might mediate and confound the LA strain vs. pressure relationship, resulting instead in a relationship between LA fibrosis and stiffness index (mean pressure/LA reservoir strain)., Methods and Results: Sixty-seven patients with AF underwent a standard cardiac MR exam including long-axis cine views (2 and 4-ch) and a free-breathing high resolution three-dimensional late gadolinium enhancement (LGE) of the atrium (N=41), within 30 days prior to AF ablation, at which procedure invasive mean left atrial pressure (LAP) was measured. LV and LA Volumes, EF, and comprehensive analysis of LA strains (strain and strain rates and strain timings during the atrial reservoir, conduit and active phases) were measured and LA fibrosis content (LGE (ml)) was assessed from 3D LGE volumes. LA LGE was well correlated to atrial stiffness index (LA mean pressure/LA reservoir strain) overall (R=0.59, p<0.001), and among patient subgroups. Pressure was only correlated to maximal LA volume (R=0.32) and the time to peak reservoir strain rate (R=0.32), among all functional measurements. LA reservoir strain was strongly correlated with LAEF (R=0.95, p<0.001) and LA minimum volume (r=0.82, p<0.001)., Conclusion: In our AF cohort, pressure is correlated to maximum LA volume and time to peak reservoir strain. LA LGE is a strong marker of stiffness., Competing Interests: Conflicts of Interest: The authors have no conflicts to disclose.
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- 2023
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24. Metastatic esthesioneuroblastoma with widespread recurrence to the central nervous system.
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Heskett C, Kabangu JL, Bhargav A, Chamoun R, and Ohiorhenuan I
- Abstract
Background: Esthesioneuroblastomas (ENBs) are rare malignancies of the upper digestive tract, often demonstrating local metastasis to the intracranial space through the cribriform plate. These tumors show high rates of recurrence locally following treatment. Here, we report a patient with advanced recurrent ENB 2 years following initial treatment, affecting both the spine and intracranial space without evidence of local recurrence or contiguous extension from the initial tumor site., Case Description: A 32-year-old male presents with a 2 month history of neurological symptoms 2 years following treatment of Kadish C/AJCC stage IVB (T4a, N3, M0) ENB. No evidence of locoregional recurrent disease was observed prior with intermittent imaging. Imaging revealed a large ventral epidural tumor invading multiple levels of the thoracic spine as well as a ring enhancing lesion in the right parietal lobe. The patient was treated surgically with debridement, decompression, and posterior stabilization of the thoracic spine followed by radiotherapy to the spinal and parietal lesions. Chemotherapy was also initiated. Despite treatment, the patient passed away 6 months after surgery., Conclusion: We report a case of delayed recurrent ENB with widespread metastases to the central nervous system without evidence of local disease or contiguous extension from initial tumor site. This represents a highly aggressive form of this tumor as recurrences are primarily locoregional. In follow-up of ENB treatment, clinicians must be cognizant of these tumors demonstrated ability to spread to distal regions. All new onset neurological symptoms should be investigated fully even if no local recurrence is observed., Competing Interests: There are no conflicts of interest., (Copyright: © 2023 Surgical Neurology International.)
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- 2023
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25. Bilateral Pulmonary Embolism Masked by New-Onset Atrial Fibrillation with Rapid Ventricular Rate: The Role of Mechanical Thrombectomy.
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Taoutel R, Beck M, Chamoun R, Caroline M, and Doroshow J
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- Aged, 80 and over, Dyspnea, Humans, Male, Thrombectomy methods, Atrial Fibrillation complications, Pulmonary Embolism complications, Pulmonary Embolism diagnosis, Pulmonary Embolism therapy, Shock, Ventricular Dysfunction, Right etiology
- Abstract
BACKGROUND Management of atrial fibrillation (AF) with rapid ventricular rate in the setting of submassive pulmonary emboli (PE) has not been well defined in the literature. It is challenging as the hemodynamics caused by a PE can change the management of AF. We report a case of bilateral PE masked by new-onset AF with rapid ventricular rate that was treated pharmaceutically and mechanically, with thrombectomy. CASE REPORT An 85-year-old man presented with gradual dyspnea and was found to be in AF with rapid ventricular rate (~160-180 bpm). The patient had tachypnea and hypoxia requiring oxygen administration. On physical examination, he had euvolemia. Chest X-ray did not reveal pulmonary vascular congestion. He was started on standard AF management with atrioventricular nodal blockers. Laboratory tests revealed a normal troponin level but mildly elevated B-type natriuretic peptide and lactate. Because his dyspnea was out of proportion to the physical examination, radiographic, and laboratory findings, a D-dimer level was obtained and was elevated. Computed tomography with pulmonary angiogram showed extensive bilateral PE. An echocardiogram (TTE) showed evidence of right ventricular failure. The patient underwent mechanical thrombectomy with clot retrieval, deterring the risk of hemodynamic collapse that would have ensued with atrioventricular nodal blockers monotherapy. On repeat TTE, right ventricular dysfunction was completely resolved and the remaining hospitalization was uneventful. CONCLUSIONS In patients with concomitant AF with rapid ventricular rate and submassive PE, the use of mechanical thrombectomy, in addition to the standard AF management, could be beneficial in deterring the risk of hemodynamic collapse.
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- 2022
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26. Micronutrient Improvement of Epithelial Barrier Function in Various Disease States: A Case for Adjuvant Therapy.
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DiGuilio KM, Rybakovsky E, Abdavies R, Chamoun R, Flounders CA, Shepley-McTaggart A, Harty RN, and Mullin JM
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- Animals, COVID-19 epidemiology, COVID-19 metabolism, COVID-19 virology, Humans, Micronutrients pharmacology, Pandemics prevention & control, SARS-CoV-2 physiology, Tight Junctions drug effects, Tight Junctions metabolism, Vitamin A pharmacology, Vitamin D pharmacology, Vitamins metabolism, Vitamins pharmacology, Zinc pharmacology, Inflammatory Bowel Diseases metabolism, Intestinal Mucosa metabolism, Micronutrients metabolism, Vitamin A metabolism, Vitamin D metabolism, Zinc metabolism
- Abstract
The published literature makes a very strong case that a wide range of disease morbidity associates with and may in part be due to epithelial barrier leak. An equally large body of published literature substantiates that a diverse group of micronutrients can reduce barrier leak across a wide array of epithelial tissue types, stemming from both cell culture as well as animal and human tissue models. Conversely, micronutrient deficiencies can exacerbate both barrier leak and morbidity. Focusing on zinc, Vitamin A and Vitamin D, this review shows that at concentrations above RDA levels but well below toxicity limits, these micronutrients can induce cell- and tissue-specific molecular-level changes in tight junctional complexes (and by other mechanisms) that reduce barrier leak. An opportunity now exists in critical care-but also medical prophylactic and therapeutic care in general-to consider implementation of select micronutrients at elevated dosages as adjuvant therapeutics in a variety of disease management. This consideration is particularly pointed amidst the COVID-19 pandemic.
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- 2022
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27. Mechanical Properties in the Glioma Microenvironment: Emerging Insights and Theranostic Opportunities.
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Bhargav AG, Domino JS, Chamoun R, and Thomas SM
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Gliomas represent the most common malignant primary brain tumors, and a high-grade subset of these tumors including glioblastoma are particularly refractory to current standard-of-care therapies including maximal surgical resection and chemoradiation. The prognosis of patients with these tumors continues to be poor with existing treatments and understanding treatment failure is required. The dynamic interplay between the tumor and its microenvironment has been increasingly recognized as a key mechanism by which cellular adaptation, tumor heterogeneity, and treatment resistance develops. Beyond ongoing lines of investigation into the peritumoral cellular milieu and microenvironmental architecture, recent studies have identified the growing role of mechanical properties of the microenvironment. Elucidating the impact of these biophysical factors on disease heterogeneity is crucial for designing durable therapies and may offer novel approaches for intervention and disease monitoring. Specifically, pharmacologic targeting of mechanical signal transduction substrates such as specific ion channels that have been implicated in glioma progression or the development of agents that alter the mechanical properties of the microenvironment to halt disease progression have the potential to be promising treatment strategies based on early studies. Similarly, the development of technology to measure mechanical properties of the microenvironment in vitro and in vivo and simulate these properties in bioengineered models may facilitate the use of mechanical properties as diagnostic or prognostic biomarkers that can guide treatment. Here, we review current perspectives on the influence of mechanical properties in glioma with a focus on biophysical features of tumor-adjacent tissue, the role of fluid mechanics, and mechanisms of mechanical signal transduction. We highlight the implications of recent discoveries for novel diagnostics, therapeutic targets, and accurate preclinical modeling of glioma., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Bhargav, Domino, Chamoun and Thomas.)
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- 2022
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28. Fatigue in breast cancer patients on chemotherapy: a cross-sectional study exploring clinical, biological, and genetic factors.
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Hajj A, Chamoun R, Salameh P, Khoury R, Hachem R, Sacre H, Chahine G, Kattan J, and Rabbaa Khabbaz L
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- Aged, Alleles, Anemia chemically induced, Anemia genetics, Breast Neoplasms psychology, CLOCK Proteins genetics, Cross-Sectional Studies, Female, France, Humans, Middle Aged, Pharmacogenomic Variants genetics, Pilot Projects, Polymorphism, Single Nucleotide, Quality of Life, Receptors, Dopamine D2 genetics, Surveys and Questionnaires, Antineoplastic Agents adverse effects, Breast Neoplasms drug therapy, Breast Neoplasms genetics, Fatigue chemically induced, Fatigue genetics
- Abstract
Background: Cancer-related fatigue (CRF) is one of the most common and distressing complaints reported by cancer patients during chemotherapy considerably impacting all aspects of a patient's life (physical, psychosocial, professional, and socioeconomic). The aim of this study was to assess the severity of cancer-related fatigue in a group of breast cancer patients undergoing chemotherapy and explore the association between fatigue scores and sociodemographic, clinical, biological, psychiatric, and genetic factors., Methods: A cross-sectional pilot study carried out at the oncology outpatient unit of Hôtel-Dieu de France University Hospital recruited 67 breast cancer patients undergoing chemotherapy between November 2017 and June 2019 to evaluate fatigue using the EORTC QLQ-C30 scale (European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire). Genotyping for seven gene polymorphisms (COMT, DRD2, OPRM1, CLOCK, PER2, CRY2, ABCB1) was performed using the Lightcycler
® (Roche)., Results: The prevalence of fatigue was 46.3%. Multivariable analysis taking the fatigue score as the dependent variable showed that a higher number of cycles and a lower hemoglobin level were significantly associated with higher odds of exhibiting fatigue. Moreover, having at least one C allele for DRD2 SNP (vs. TT) was significantly associated with a 4.09 higher odds of expressing fatigue compared to TT patients. Finally, patients with at least one C allele for CLOCK SNP tended to display higher fatigue levels than TT patients., Conclusions: Our study showed that anemic breast cancer patients with a high number of chemotherapy cycles and those carrying at least one C allele for DRD2 and CLOCK SNPs are at greater risk of exhibiting fatigue. Since no previous research has reported such genetic results, future studies are necessary to confirm our findings., (© 2021. The Author(s).)- Published
- 2022
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29. 5-Aminolevulinic acid for enhanced surgical visualization of high-grade gliomas: a prospective, multicenter study.
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Schupper AJ, Baron RB, Cheung W, Rodriguez J, Kalkanis SN, Chohan MO, Andersen BJ, Chamoun R, Nahed BV, Zacharia BE, Kennedy J, Moulding HD, Zucker L, Chicoine MR, Olson JJ, Jensen RL, Sherman JH, Zhang X, Price G, Fowkes M, Germano IM, Carter BS, Hadjipanayis CG, and Yong RL
- Abstract
Objective: Greater extent of resection (EOR) is associated with longer overall survival in patients with high-grade gliomas (HGGs). 5-Aminolevulinic acid (5-ALA) can increase EOR by improving intraoperative visualization of contrast-enhancing tumor during fluorescence-guided surgery (FGS). When administered orally, 5-ALA is converted by glioma cells into protoporphyrin IX (PPIX), which fluoresces under blue 400-nm light. 5-ALA has been available for use in Europe since 2010, but only recently gained FDA approval as an intraoperative imaging agent for HGG tissue. In this first-ever, to the authors' knowledge, multicenter 5-ALA FGS study conducted in the United States, the primary objectives were the following: 1) assess the diagnostic accuracy of 5-ALA-induced PPIX fluorescence for HGG histopathology across diverse centers and surgeons; and 2) assess the safety profile of 5-ALA FGS, with particular attention to neurological morbidity., Methods: This single-arm, multicenter, prospective study included adults aged 18-80 years with Karnofsky Performance Status (KPS) score > 60 and an MRI diagnosis of suspected new or recurrent resectable HGG. Intraoperatively, 3-5 samples per tumor were taken and their fluorescence status was recorded by the surgeon. Specimens were submitted for histopathological analysis. Patients were followed for 6 weeks postoperatively for adverse events, changes in the neurological exam, and KPS score. Multivariate analyses were performed of the outcomes of KPS decline, EOR, and residual enhancing tumor volume to identify predictive patient and intraoperative variables., Results: Sixty-nine patients underwent 5-ALA FGS, providing 275 tumor samples for analysis. PPIX fluorescence had a sensitivity of 96.5%, specificity of 29.4%, positive predictive value (PPV) for HGG histopathology of 95.4%, and diagnostic accuracy of 92.4%. Drug-related adverse events occurred at a rate of 22%. Serious adverse events due to intraoperative neurological injury, which may have resulted from FGS, occurred at a rate of 4.3%. There were 2 deaths unrelated to FGS. Compared to preoperative KPS scores, postoperative KPS scores were significantly lower at 48 hours and 2 weeks but were not different at 6 weeks postoperatively. Complete resection of enhancing tumor occurred in 51.9% of patients. Smaller preoperative tumor volume and use of intraoperative MRI predicted lower residual tumor volume., Conclusions: PPIX fluorescence, as judged by the surgeon, has a high sensitivity and PPV for HGG. 5-ALA was well tolerated in terms of drug-related adverse events, and its application by trained surgeons in FGS for HGGs was not associated with any excess neurological morbidity.
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- 2021
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30. Compartmentalization: An Open Technique for Frontal Sinus Repair and Preservation-Description of Technique and Early Case Series.
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Miller C, Weisbrod L, Beahm D, and Chamoun R
- Abstract
Background Cranialization or obliteration is widely accepted intervention for traumatic or intentional breach of the frontal sinus. These techniques, however, result in the loss of frontal sinus function and have a persistent risk of cerebrospinal fluid (CSF) leak and mucocele. Compartmentalization is an open technique for repair of the frontal sinus using allograft onlay and a vascularized periosteal flap that allows for preservation of frontal sinus function. Objective The main objective of this article is to describe the technique for compartmentalization of the frontal sinus and demonstrate its efficacy and complication rate with an early patient series. Methods Our technique includes the following key components: harvesting of a pedicled periosteal flap, frontal sinus repair through a bifrontal craniotomy with minimal mucosa removal, ensuring the patency of the nasal frontal outflow tract, and separation of the brain from the frontal sinus with a dual layer of periosteum and allograft. All cases of frontal sinus repair using the compartmentalization technique at our institution were reviewed. Charts were reviewed for CSF leak, mucocele, and other complications. Results Twenty-three patients underwent the described frontal sinus repair technique 17 for tumor and 6 for trauma. There were no CSF leaks and no mucoceles. One patient experienced postoperative anemia and a "parameningeal reaction" that were managed with a short course of antibiotics. Conclusions Compartmentalization, due to its sinus preservation and low complication rate, represents a meaningful step forward in neurosurgical technique for open frontal sinus repair. However, long-term outcomes are necessary to fully evaluate risk of mucocele., Competing Interests: Conflict of Interest None., (Thieme. All rights reserved.)
- Published
- 2021
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31. Temporal Trends in Arrhythmogenicity Related to Treatment of COVID-19 Infection.
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Hummel JP, Maraj I, Taoutel R, Chamoun R, Workman VK, Tran L, Abboud JM, Afif C, Chouairi S, Delvecchio A, Howes CJ, Enriquez AD, and Akar JG
- Subjects
- Action Potentials drug effects, Aged, Antiviral Agents pharmacokinetics, Arrhythmias, Cardiac diagnosis, Arrhythmias, Cardiac physiopathology, COVID-19, Cardiotoxicity, Coronavirus Infections diagnosis, Coronavirus Infections virology, Female, Humans, Hydroxychloroquine pharmacokinetics, Male, Middle Aged, Pandemics, Pneumonia, Viral diagnosis, Pneumonia, Viral virology, Retrospective Studies, Risk Assessment, Risk Factors, Time Factors, Treatment Outcome, COVID-19 Drug Treatment, Antiviral Agents adverse effects, Arrhythmias, Cardiac chemically induced, Coronavirus Infections drug therapy, Heart Rate drug effects, Hydroxychloroquine adverse effects, Pneumonia, Viral drug therapy
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- 2020
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32. Incidence and determinants of QT interval prolongation in COVID-19 patients treated with hydroxychloroquine and azithromycin.
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Maraj I, Hummel JP, Taoutel R, Chamoun R, Workman V, Li C, Tran L, DelVecchio A, Howes C, and Akar JG
- Subjects
- Azithromycin adverse effects, Humans, Hydroxychloroquine adverse effects, Incidence, Pandemics, Patients, SARS-CoV-2, COVID-19, Long QT Syndrome epidemiology, Torsades de Pointes
- Published
- 2020
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33. Laser ablation after stereotactic radiosurgery: a multicenter prospective study in patients with metastatic brain tumors and radiation necrosis.
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Ahluwalia M, Barnett GH, Deng D, Tatter SB, Laxton AW, Mohammadi AM, Leuthardt E, Chamoun R, Judy K, Asher A, Essig M, Dietrich J, and Chiang VL
- Subjects
- Ablation Techniques, Adult, Aged, Brain Neoplasms secondary, Female, Humans, Karnofsky Performance Status, Magnetic Resonance Imaging, Male, Middle Aged, Necrosis, Neoplasm Recurrence, Local, Postoperative Complications diagnostic imaging, Postoperative Complications psychology, Progression-Free Survival, Prospective Studies, Quality of Life, Radiation Injuries diagnostic imaging, Radiation Injuries psychology, Radiosurgery adverse effects, Treatment Outcome, Brain Neoplasms surgery, Laser Therapy methods, Postoperative Complications surgery, Radiation Injuries surgery, Radiosurgery methods
- Abstract
Objective: Laser Ablation After Stereotactic Radiosurgery (LAASR) is a multicenter prospective study of laser interstitial thermal (LITT) ablation in patients with radiographic progression after stereotactic radiosurgery for brain metastases., Methods: Patients with a Karnofsky Performance Scale (KPS) score ≥ 60, an age > 18 years, and surgical eligibility were included in this study. The primary outcome was local progression-free survival (PFS) assessed using the Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) criteria. Secondary outcomes were overall survival (OS), procedure safety, neurocognitive function, and quality of life., Results: Forty-two patients—19 with biopsy-proven radiation necrosis, 20 with recurrent tumor, and 3 with no diagnosis—were enrolled. The median age was 60 years, 64% of the subjects were female, and the median baseline KPS score was 85. Mean lesion volume was 6.4 cm3 (range 0.4–38.6 cm3). There was no significant difference in length of stay between the recurrent tumor and radiation necrosis patients (median 2.3 vs 1.7 days, respectively). Progression-free survival and OS rates were 74% (20/27) and 72%, respectively, at 26 weeks. Thirty percent of subjects were able to stop or reduce steroid usage by 12 weeks after surgery. Median KPS score, quality of life, and neurocognitive results did not change significantly for either group over the duration of survival. Adverse events were also similar for the two groups, with no significant difference in the overall event rate. There was a 12-week PFS and OS advantage for the radiation necrosis patients compared with the recurrent tumor or tumor progression patients., Conclusions: In this study, in which enrolled patients had few alternative options for salvage treatment, LITT ablation stabilized the KPS score, preserved quality of life and cognition, had a steroid-sparing effect, and was performed safely in the majority of cases.
- Published
- 2019
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34. Betrixaban: A Novel Oral Anticoagulant With a New Niche.
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Murphy G, Grace Y, Chaudry S, and Chamoun R
- Abstract
Objective: To evaluate the efficacy, safety, and clinical implication of betrixaban for prophylaxis of venous thromboembolism (VTE) in patients with acute medical illness. Data Sources: A search for clinical trials was performed from January 2006 to January 2017 in English language using Clinicaltrials.gov and PubMed/MEDLINE. The following search terms were used: betrixaban, pharmacokinetics, pharmacology, and drug safety. Study Selection: The following limits were used to access the clinical trials: controlled clinical trial, randomized clinical trial, clinical trial, clinical trial phase II, and clinical trial phase III. The search was narrowed to include only humans. Data Extraction: The search criteria resulted in 6 clinical trials assessing the safety and efficacy of betrixaban. Additionally, references from publications assessing the safety and efficacy of betrixaban in atrial fibrillation, treatment and prevention of VTE, and extended duration VTE prophylaxis were assessed. Data Synthesis: Prior to 2017, no anticoagulant therapy had been approved for extended VTE prophylaxis in acutely ill medical patients. Betrixaban is the first direct oral anticoagulant approved for VTE prophylaxis in adult, acutely ill patients at risk for thromboembolisms. Based on the APEX trial, betrixaban 80 mg administered daily for 35 to 42 days was compared to enoxaparin administered daily for 6 to 14 days. In 7441 patients, fewer VTEs were seen in the betrixaban compared to enoxaparin with no significant difference in adverse reactions. Conclusion: Based on clinical trials, betrixaban appears to be safe and effective in preventing VTE in acutely ill patients who are at risk of developing VTE., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2018.)
- Published
- 2018
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35. Endoscopically Assisted Drilling, Exposure of the Fundus through a Presigmoid Retrolabyrinthine Approach: A Cadaveric Feasibility Study.
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Muelleman T, Shew M, Alvi S, Shah K, Staecker H, Chamoun R, and Lin J
- Subjects
- Cadaver, Cerebellopontine Angle anatomy & histology, Ear, Inner anatomy & histology, Feasibility Studies, Humans, Cerebellopontine Angle surgery, Ear, Inner surgery, Endoscopy methods
- Abstract
The presigmoid retrolabyrinthine approach to the cerebellopontine angle is traditionally described to not provide access to the internal auditory canal (IAC). We aimed to evaluate the extent of the IAC that could be exposed with endoscopically assisted drilling and to measure the percentage of the IAC that could be visualized with the microscope and various endoscopes after drilling had been completed. Presigmoid retrolabyrinthine approaches were performed bilaterally on 4 fresh cadaveric heads. We performed endoscopically assisted drilling to expose the fundus of the IAC, which resulted in exposure of the entire IAC in 8 of 8 temporal bone specimens. The microscope afforded a mean view of 83% (n = 8) of the IAC. The 0°, 30°, 45°, and 70° endoscope each afforded a view of 100% of the IAC in 8 of 8 temporal bone specimens. In conclusion, endoscopic drilling of the IAC of can provide an extradural means of exposing the entire length of the IAC while preserving the labyrinth.
- Published
- 2018
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36. Does a not-so-recent ankle sprain influence interjoint coordination during walking?
- Author
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Dedieu P, Chamoun R, Lacaud G, Moulinat T, Queron M, and Zanone PG
- Subjects
- Biomechanical Phenomena, Gait physiology, Humans, Male, Muscle, Skeletal physiology, Psychomotor Performance, Young Adult, Ankle Injuries physiopathology, Ankle Joint physiology, Sprains and Strains physiopathology, Walking physiology
- Abstract
Background: Ankle sprains are common joint injuries in daily and sports activities, whose underlying mechanisms have been amply studied. If joint structures are directly damaged, neuromuscular activity can be affected, particularly in the time domain. This study aims to establish whether previous ankle injury correlates with changes in the inter-joint synergy of the entire lower limb and in the muscle activity pattern during walking., Methods: Three-dimensional walking-gait analysis was conducted on twenty-four adults. Ten of them had never suffered from ankle sprain; fourteen had suffered from ankle sprain at least once during the three preceding years. Continuous Relative Phase (CRP) between the moving limbs assessed inter-joint coordination, and muscular activity was recorded by EMG., Findings: CRP between ankle and knee and between ankle and hip indicates that both joints moved in tight synchronization in the same direction on the injured side, whereas there was a time lag between joints on the healthy side for each sprained participants or on both side for the control group. Start-time and/or duration of muscular activity of tibialis anterior, soleus and peroneus longus occurred earlier and were longer on the injured side, respectively., Interpretation: Our findings suggest that ankle sprain modifies inter-joint coordination and muscular activity of the injured limb, inducing not an entirely new pattern of coordination but an alteration of the existing pattern. CRP revealed slight modifications in the extant inter-joint coordination which may not be captured by other kinematic variables, which opens perspectives on therapy and relapse prevention., (Copyright © 2017 Elsevier Ltd. All rights reserved.)
- Published
- 2017
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37. Morphometric Analysis of the Middle Clinoid Process Using Maxillofacial Computed Tomography Scans.
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Miller C, Chamoun R, and Beahm D
- Subjects
- Adult, Aged, Female, Humans, Imaging, Three-Dimensional, Male, Middle Aged, Skull Base diagnostic imaging, Sphenoid Bone diagnostic imaging, Sella Turcica diagnostic imaging, Tomography, X-Ray Computed methods
- Abstract
Background: The interest in detailed anatomy of the sella and parasellar regions has resurged recently due to the wide clinical applications of the expanded endoscopic approaches to the skull base. The middle clinoid process (MCP) is a bony structure that can affect wide endoscopic exposure of the sella and parasellar region., Objective: To study and analyze the anatomic variations of the MCP in the general population using computed tomography scans., Methods: A total of 150 maxillofacial computed tomography scans were reviewed to characterize the MCP. Only adult patients without intracranial or nasal pathology were included. Measurements were made in the axial and sagittal planes to determine the maximum diameter, length, angulation, and location of the MCP., Results: The prevalence of the MCP was 30.7% in male and 42.7% in female patients. Of the MCPs, 41.8% were ring forming, whereas 76.4% were pneumatized. Quantitatively, the average axial base diameter was 4.6 ± 1.4 mm, the average sagittal base diameter was 5.0 ± 1.8 mm, the average length was 4.7 ± 1.7 mm, the average midline distance was 5.9 ± 2.3 mm, the average distance from the sellar-clival junction was 10.6 ± 3.3 mm, the average sagittal angle was 91.0 ± 21.1°, and the average axial angle was 45.2 ± 15.5°. A significant increase was found in the prevalence of MCPs in white patients compared with black patients, and a significantly greater midline distance and axial angle were found in male compared with female patients., Conclusion: A clear understanding of the sellar and parasellar anatomy is crucial for successful and safe expanded endoscopic approaches. This study provides a quantitative anatomic characterization of the MCP in the U.S. population with demographic data analysis., (Copyright © 2016 by the Congress of Neurological Surgeons)
- Published
- 2017
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38. Rosette-forming glioneuronal tumor of the thalamus.
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Eastin M, Shah KJ, Newell KL, and Chamoun R
- Subjects
- Adult, Female, Humans, Rosette Formation, Brain Neoplasms pathology, Neoplasms, Neuroepithelial pathology, Thalamus pathology
- Published
- 2016
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39. Delayed intraventricular metastasis of clival chordoma.
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Smith KA, Crabtree K, and Chamoun R
- Published
- 2016
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40. Genes of the de novo and Salvage Biosynthesis Pathways of Vitamin B6 are Regulated under Oxidative Stress in the Plant Pathogen Rhizoctonia solani.
- Author
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Samsatly J, Chamoun R, Gluck-Thaler E, and Jabaji S
- Abstract
Vitamin B6 is recognized as an important cofactor required for numerous metabolic enzymes, and has been shown to act as an antioxidant and play a role in stress responses. It can be synthesized through two different routes: salvage and de novo pathways. However, little is known about the possible function of the vitamin B6 pathways in the fungal plant pathogen Rhizoctonia solani. Using genome walking, the de novo biosynthetic pathway genes; RsolPDX1 and RsolPDX2 and the salvage biosynthetic pathway gene, RsolPLR were sequenced. The predicted amino acid sequences of the three genes had high degrees of similarity to other fungal PDX1, PDX2, and PLR proteins and are closely related to other R. solani anastomosis groups. We also examined their regulation when subjected to reactive oxygen species (ROS) stress inducers, the superoxide generator paraquat, or H2O2, and compared it to the well-known antioxidant genes, catalase and glutathione-S-transferase (GST). The genes were differentially regulated with transcript levels as high as 33 fold depending on the gene and type of stress reflecting differences in the type of damage induced by ROS. Exogenous addition of the vitamers PN or PLP in culture medium significantly induced the transcription of the vitamin B6 de novo encoding genes as early as 0.5 hour post treatment (HPT). On the other hand, transcription of RsolPLR was vitamer-specific; a down regulation upon supplementation of PN and upregulation with PLP. Our results suggest that accumulation of ROS in R. solani mycelia is linked to transcriptional regulation of the three genes and implicate the vitamin B6 biosynthesis machinery in R. solani, similar to catalases and GST, as an antioxidant stress protector against oxidative stress.
- Published
- 2016
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41. Neuroendoscopic treatment of symptomatic giant Virchow-Robin spaces.
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Smith KA, Lavin P, and Chamoun R
- Abstract
Background: Virchow-Robin spaces (VRS) or perivascular spaces are interstitial cystic spaces surrounding the vasculature of brain parenchyma and course from the subarachnoid space. Small VRS (<2 mm) appear in all age groups, but can enlarge and be confused with other lesions like cystic neoplasms. These enlarged VRS are termed giant tumefactive perivascular spaces (GRPVS)., Case Description: We present the case of a 50-year-old male who presents with right eye pain, blurred vision, headache, and gait imbalance. He was diagnosed with GRPVS and underwent an endoscopic third ventriculostomy and cyst fenestration. Postoperative imaging showed a decrease in size of the ventricular system with evidence of flow through the aqueduct and ventriculostomy. Brainstem VRS cysts decreased in size., Conclusion: Unlike the other small number of case reports, this patient is unique in his age of presentation and successful endoscopic method of treatment. The endoscopic approach provided great exposure and adequate access to the lesions. Clinically, symptoms improved, cyst size decreased, and need for permanent shunt placement was averted.
- Published
- 2015
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42. Suppression subtractive hybridization and comparative expression of a pore-forming toxin and glycosyl hydrolase genes in Rhizoctonia solani during potato sprout infection.
- Author
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Chamoun R, Samsatly J, Pakala SB, Cubeta MA, and Jabaji S
- Subjects
- Amino Acid Sequence, Bacillus subtilis physiology, Base Sequence, DNA, Complementary genetics, Down-Regulation, Fungal Proteins genetics, Gene Library, Genome, Fungal genetics, Glycoside Hydrolases metabolism, Host-Pathogen Interactions, Molecular Sequence Data, Mycotoxins metabolism, Phylogeny, Plant Diseases microbiology, Rhizoctonia cytology, Rhizoctonia enzymology, Sequence Analysis, DNA, Stachybotrys physiology, Up-Regulation, Gene Expression Regulation, Fungal genetics, Glycoside Hydrolases genetics, Mycotoxins genetics, Rhizoctonia genetics, Solanum tuberosum microbiology, Subtractive Hybridization Techniques methods
- Abstract
Rhizoctonia solani is a plant pathogenic fungus that causes black scurf on tubers and stem and stolon canker on underground parts of potato plant. Early in the season, the fungus attacks germinating sprouts underground before they emerge from the soil. Damage at this stage results in delayed emergence of weakened plants with poor and uneven stands. The mechanism underlying this phenomenon has been investigated in this study by coupling a cDNA-suppression subtractive hybridization (SSH) library to differential screening to identify transcripts of R. solani that are down-regulated during infection of potato sprouts. We report on the identification of 33 unique genes with functions related to carbohydrate binding, vitamin synthesis, pathogenicity, translation, ATP and nucleic acid binding and other categories. RACE-PCR was used to clone and characterize the first full-length cDNA clones, RSENDO1 and RSGLYC1 that encode for an eukaryotic delta-endotoxin CytB protein and an intracellular glycosyl hydrolase, respectively. Quantitative real-time PCR revealed the down-regulation of RSENDO1 during infection of potato sprouts and the up-regulation of RSGLYC1 when the fungus was grown on a cellulose-based nutrient medium. In contrast, additional experiments have highlighted the down-regulation of RSENDO1 when R. solani was co-cultured with the mycoparasite Stachybotrys elegans and the bacterial antagonist Bacillus subtilis B26. These results advance our understanding of R. solani-potato interaction in subterranean parts of the plant. Such approaches could be considered in building an efficient integrated potato disease management program.
- Published
- 2015
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43. Metabolic responses of willow (Salix purpurea L.) leaves to mycorrhization as revealed by mass spectrometry and (1)H NMR spectroscopy metabolite profiling.
- Author
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Aliferis KA, Chamoun R, and Jabaji S
- Abstract
Unlabelled: The root system of most terrestrial plants form symbiotic interfaces with arbuscular mycorrhizal fungi (AMF), which are important for nutrient cycling and ecosystem sustainability. The elucidation of the undergoing changes in plants' metabolism during symbiosis is essential for understanding nutrient acquisition and for alleviation of soil stresses caused by environmental cues. Within this context, we have undertaken the task of recording the fluctuation of willow (Salix purpurea L.) leaf metabolome in response to AMF inoculation. The development of an advanced metabolomics/bioinformatics protocol employing mass spectrometry (MS) and (1)H NMR analyzers combined with the in-house-built metabolite library for willow (http://willowmetabolib., Research: mcgill.ca/index.html) are key components of the research. Analyses revealed that AMF inoculation of willow causes up-regulation of various biosynthetic pathways, among others, those of flavonoid, isoflavonoid, phenylpropanoid, and the chlorophyll and porphyrin pathways, which have well-established roles in plant physiology and are related to resistance against environmental stresses. The recorded fluctuation in the willow leaf metabolism is very likely to provide AMF-inoculated willows with a significant advantage compared to non-inoculated ones when they are exposed to stresses such as, high levels of soil pollutants. The discovered biomarkers of willow response to AMF inoculation and corresponding pathways could be exploited in biomarker-assisted selection of willow cultivars with superior phytoremediation capacity or genetic engineering programs.
- Published
- 2015
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44. Identification of signatory secondary metabolites during mycoparasitism of Rhizoctonia solani by Stachybotrys elegans.
- Author
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Chamoun R, Aliferis KA, and Jabaji S
- Abstract
Stachybotrys elegans is able to parasitize the fungal plant pathogen Rhizoctonia solani AG-3 following a complex and intimate interaction, which, among others, includes the production of cell wall-degrading enzymes, intracellular colonization, and expression of pathogenic process encoding genes. However, information on the metabolome level is non-existent during mycoparasitism. Here, we performed a direct-infusion mass spectrometry (DIMS) metabolomics analysis using an LTQ Orbitrap analyzer in order to detect changes in the profiles of induced secondary metabolites of both partners during this mycoparasitic interaction 4 and 5 days following its establishment. The diketopiperazine(s) (DKPs) cyclo(S-Pro-S-Leu)/cyclo(S-Pro-S-Ile), ethyl 2-phenylacetate, and 3-nitro-4-hydroxybenzoic acid were detected as the primary response of Rhizoctonia 4 days following dual-culturing with Stachybotrys, whereas only the latter metabolite was up-regulated 1 day later. On the other hand, trichothecenes and atranones were mycoparasite-derived metabolites identified during mycoparasitism 4 and 5 days following dual-culturing. All the above secondary metabolites are known to exhibit bioactivity, including fungitoxicity, and represent key elements that determine the outcome of the interaction being studied. Results could be further exploited in programs for the evaluation of the bioactivity of these metabolites per se or their chemical analogs, and/or genetic engineering programs to obtain more efficient mycoparasite strains with improved efficacy and toxicological profiles.
- Published
- 2015
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45. Hearing preservation after middle fossa vestibular schwannoma removal: are the results durable?
- Author
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Quist TS, Givens DJ, Gurgel RK, Chamoun R, and Shelton C
- Subjects
- Adult, Aged, Aged, 80 and over, Audiometry, Pure-Tone, Cranial Fossa, Middle surgery, Female, Humans, Male, Microsurgery, Middle Aged, Neurosurgical Procedures methods, Treatment Outcome, Hearing, Neuroma, Acoustic surgery, Otologic Surgical Procedures methods
- Abstract
Objective: To describe 5-year hearing preservation rates following microsurgical excision of vestibular schwannoma (VS) via the middle cranial fossa (MCF) approach., Study Design: Case series with chart review., Setting: This study was performed at a tertiary care academic medical center., Subjects and Methods: Fifty-seven subjects with VS underwent resection via an MCF approach between February 1998 and January 2009. Pure-tone average (PTA) and word recognition score (WRS) were obtained preoperatively, immediately postoperatively, and at 5-year follow-up., Results: Preoperative serviceable hearing (American Academy of Otolaryngology-Head and Neck Surgery class A/B) was present in 49 (86%) of the 57 patients, with an average PTA of 23 dB (range, 1-50 dB) and an average WRS of 97% (range, 76%-100%). Immediate postoperative serviceable hearing was maintained in 27 (55%) patients, with an average PTA and WRS of 31 dB (5-50 dB) and 96% (70%-100%), respectively. Five-year follow-up was available for 16 of the 27 patients. Twelve (75%) of the 16 patients maintained serviceable hearing with an average PTA and WRS of 35 dB (4-49 dB) and 95% (84%-100%), respectively. Of the 16 subjects who did maintain class A or B hearing, the mean change in PTA and WRS was 5 dB and 0.4%, respectively. Of the 4 patients who did not maintain class A/B hearing, average change in PTA and WRS was 16 dB (4.5-23 dB) and 16% (0%-40%), respectively., Conclusions: For patients with VS in whom serviceable hearing is preserved following the MCF approach, the long-term hearing outcome remains durable in most patients., (© American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.)
- Published
- 2015
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46. Insight into sulfur reactions in Li-S batteries.
- Author
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Xu R, Belharouak I, Zhang X, Chamoun R, Yu C, Ren Y, Nie A, Shahbazian-Yassar R, Lu J, Li JC, and Amine K
- Abstract
Understanding and controlling the sulfur reduction species (Li2Sx, 1 ≤ x ≤ 8) under realistic battery conditions are essential for the development of advanced practical Li-S cells that can reach their full theoretical capacity. However, it has been a great challenge to probe the sulfur reduction intermediates and products because of the lack of methods. This work employed various ex situ and in situ methods to study the mechanism of the Li-S redox reactions and the properties of Li2Sx and Li2S. Synchrotron high-energy X-ray diffraction analysis used to characterize dry powder deposits from lithium polysulfide solution suggests that the new crystallite phase may be lithium polysulfides. The formation of Li2S crystallites with a polyhedral structure was observed in cells with both the conventional (LiTFSI) electrolyte and polysulfide-based electrolyte. In addition, an in situ transmission electron microscopy experiment observed that the lithium diffusion to sulfur during discharge preferentially occurred at the sulfur surface and formed a solid Li2S crust. This may be the reason for the capacity fade in Li-S cells (as also suggested by EIS experiment in Supporting Information ). The results can be a guide for future studies and control of the sulfur species and meanwhile a baseline for approaching the theoretical capacity of the Li-S battery.
- Published
- 2014
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47. Endoscopic extracapsular dissection for resection of pituitary macroadenomas: technical note.
- Author
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Chamoun R, Takashima M, and Yoshor D
- Subjects
- Adenoma pathology, Humans, Magnetic Resonance Imaging, Male, Middle Aged, Pituitary Neoplasms pathology, Treatment Outcome, Adenoma surgery, Neurosurgical Procedures methods, Pituitary Neoplasms surgery
- Abstract
Objective: With the increasing use of the endoscope in neurosurgery, transsphenoidal surgery has undergone a considerable technical evolution. However, most recently reported advances relate to the approach to the sella turcica or to extended transsphenoidal approaches, whereas the dissection technique for pituitary tumor removal itself has received more limited attention. A notable exception is Oldfield's elegant description of an extracapsular dissection of functional pituitary microadenomas. Our objective is to describe and illustrate our technique for endoscopic extracapsular resection of pituitary macroadenomas., Methods: Influenced by Oldfield's description, we have adopted an extracapsular dissection technique in the endoscopic resection of pituitary macroadenomas. After carefully opening the dura without disrupting the macroadenoma pseudocapsule, the pseudocapsule is dissected inferiorly and laterally. The tumor is then internally debulked and the extracapsular dissection is extended circumferentially; the resection is then complete., Results: The enhanced visualization and illumination afforded by the endoscope enables the identification and surgical dissection of the pseudocapsule at the periphery of the macroadenomas under direct vision in most cases. As demonstrated in the illustrative case, working around the macroadenoma pseudocapsule allows for a definitive and complete macroadenoma resection with direct visual confirmation and with preservation of the normal gland and diaphragma., Conclusion: The endoscopic transsphenoidal approach permits an extracapsular dissection of many pituitary macroadenomas. In our preliminary experience, this technique appears to result in a high rate of complete resection without an increase in complications., (Georg Thieme Verlag KG Stuttgart · New York.)
- Published
- 2014
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48. Gonadotroph adenoma with secondary hypersecretion of testosterone.
- Author
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Chamoun R, Layfield L, and Couldwell WT
- Subjects
- Follicle Stimulating Hormone blood, Gonadotropins metabolism, Hemianopsia etiology, Humans, Luteinizing Hormone blood, Magnetic Resonance Imaging, Male, Middle Aged, Neurosurgical Procedures methods, Sphenoid Bone surgery, Treatment Outcome, Vision Disorders etiology, Adenoma metabolism, Adenoma pathology, Gonadotrophs metabolism, Gonadotrophs pathology, Pituitary Neoplasms metabolism, Pituitary Neoplasms pathology, Testosterone metabolism
- Abstract
Objective: Gonadotroph pituitary adenomas are common, but the overwhelming majority are classified as nonfunctioning adenomas. Approximately one-third secrete follicle-stimulating hormone (FSH) and/or luteinizing hormone (LH), resulting in an increase in serum levels; however, the sex hormone levels are typically not elevated and the secreted gonadotropin hormones are thought to be biologically inactive. Rarely, gonadotroph adenomas induce an ovarian hyperstimulation syndrome in females. In males, an increase in the testosterone level is even rarer. The authors report the case of a male patient with a gonadotroph pituitary adenoma causing hypersecretion of testosterone and review the medical literature., Case Description: A 45-year-old man had progressive bilateral visual loss over a 4-year period. Bitemporal hemianopsia was diagnosed by an ophthalmologist, but no other symptoms were reported. Neurosurgical evaluation was otherwise normal. Magnetic resonance imaging of the brain showed a large enhancing sellar and suprasellar tumor consistent with pituitary macroadenoma. Levels of FSH, LH, α-subunit, testosterone, free testosterone, and prolactin were elevated. The patient underwent transsphenoidal resection of the pituitary tumor. Pathologic analysis confirmed the diagnosis of pituitary adenoma, and immunohistochemistry demonstrated a population of cells with cytoplasmic staining for FSH but not for LH. The postoperative hormonal profile showed normalization of FSH and low LH, testosterone, morning cortisol level, and free thyroxine. The patient was treated with levothyroxine and hydrocortisone therapy for replacement. His vision subjectively improved at a formal visual testing follow-up to monitor the degree of improvement., Conclusions: Gonadotroph adenomas are considered a type of nonfunctioning pituitary tumors, because the commonly associated increase in serum FSH and LH does not typically result in elevated sex hormone levels. Herein, we report a rare case of high testosterone level caused by a gonadotroph adenoma successfully treated with transsphenoidal resection. Interestingly, in adult males, the increase in sex hormones does not seem to lead to a recognizable clinical syndrome, and the clinical presentation remains similar to that of nonfunctioning adenomas., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
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49. Supraclinoid internal carotid artery-inferior petrosal sinus arteriovenous fistula after high-voltage electrical burn injury.
- Author
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Krisht KM, Chamoun R, and Couldwell WT
- Subjects
- Aneurysm, False diagnostic imaging, Aneurysm, False etiology, Aneurysm, False surgery, Angiography, Digital Subtraction, Arteriovenous Fistula surgery, Carotid Artery, Internal surgery, Cranial Sinuses surgery, Embolization, Therapeutic, Humans, Male, Neurosurgical Procedures, Surgical Instruments, Young Adult, Arteriovenous Fistula diagnostic imaging, Arteriovenous Fistula etiology, Burns, Electric complications, Carotid Artery, Internal diagnostic imaging, Cranial Sinuses diagnostic imaging
- Abstract
High-voltage electrical burns can cause immediate and long-term neurological and cerebrovascular injuries. The authors present a 21-year-old man who developed an intracranial arteriovenous fistula secondary to high-voltage electrical injury. CT angiography demonstrated a left supraclinoid internal carotid artery (ICA)-inferior petrosal sinus (IPS) fistula. A subsequent angiogram revealed an irregularity of the cavernous and supraclinoid ICA with stenosis involving the supraclinoid segment and a fistulous connection between the ICA and IPS distal to the ophthalmic take-off and proximal to the anterior choroidal artery. The patient underwent a decompressive hemicraniectomy and clip-wrapping of his ICA pseudoaneurysm with successful obliteration of the fistulous connection. To our knowledge, this is the first report of an intracranial arteriovenous fistula secondary to an electrical burn injury., (Copyright © 2012 Elsevier Ltd. All rights reserved.)
- Published
- 2013
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50. Characterization and transcriptional regulation of Stachybotrys elegans mitogen-activated-protein kinase gene smkA following mycoparasitism and starvation conditions.
- Author
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Chamoun R, Aliferis KA, and Jabaji SH
- Subjects
- Amino Acid Sequence, Blotting, Western, Chromatography, Liquid, Mass Spectrometry, Molecular Sequence Data, Phosphorylation, Phylogeny, Real-Time Polymerase Chain Reaction, Sequence Alignment, Stachybotrys classification, Stachybotrys enzymology, Stachybotrys genetics, Stress, Physiological genetics, Gene Expression Regulation, Fungal, Microbial Interactions genetics, Mitogen-Activated Protein Kinases genetics, Mitogen-Activated Protein Kinases metabolism, Rhizoctonia physiology, Stachybotrys physiology
- Abstract
Mitogen-activated protein kinase (MAPK) signaling pathways play an important role in the development and conidiation of fungal pathogens on their hosts and the sensing of host-derived cues. Mycoparasitism is a fungus-fungus interaction comprising host-pathogen cross talk. Until now, only little information is available on the role of the MAPK signaling pathway during this interaction. Here, we report on the differential expression of a MAPK/ERK gene in the mycoparasite Stachybotrys elegans in response to direct parasitism of different vegetative structures of the plant pathogen Rhizoctonia solani (i.e., carbon-rich condition) and to nutrient starvation (i.e., carbon-poor condition). Western blot analysis against ERK1/2 highlighted an increase in their phosphorylated forms when S. elegans was grown under starvation condition compared to that detected in response to mycoparasitism. A higher abundance of phosphorylated ERK1/2 at the third day of interaction compared to that estimated under starvation condition was detected applying LC-MS/MS. At the transcriptional level, smkA, a YERK1 class member, was significantly induced in response to hyphal parasitism compared to parasitized sclerotia at 3, 4, and 5 days of interaction. However, under starvation condition, smkA levels were significantly induced after 7 days of growth. Southern blot analysis revealed that smkA is member of a small gene family. Collectively, these results suggest that smkA could be implicated in the mycoparasitic process in S. elegans as well as in stress-activated pathways. These results may be of wider significance in other fungus-fungus interactions.
- Published
- 2013
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