62 research outputs found
Contribution de la biopsie stereotaxique dans la prise en charge des tumeurs cerebrales: a propos de 283 cas
Introduction L’avènement de la biopsie stéréotaxique (BST) et le développement du scanner et de l’IRM ont amélioré la prise en charge des tumeurs cérébrales. Le but de cette étude est d’évaluer le rôle de la BST dans la prise en charge des tumeurs cérébrales. Matériel et Méthodes Etude rétrospective de 1995 à 2008 concernant 283 patients consécutifs ayant des tumeurs cérébrales, ayant bénéficié d’une BST, colligés au service de Neurochirurgie. L’âge moyen était de 45.5 ans (9 à 84). La BST fut réalisée sous guidage scannographique dans 260 cas et sous guidage IRM dans 23 cas. Pour les tumeurs pinéales, depuis Janvier 2000, une artériographie avec temps phlébographique et IRM préopératoire ont été jugées utiles pour éviter les complications hémorragiques. Resultats Dans 271 cas, la BST était concluante dès la première tentative (95.7%). La répétition de la BST a permis de rétablir un diagnostic précis. Il s’agissait de lésions malignes (70 % des cas). La mortalité péri-opératoire est passé de 5,9% avant 2000 à 0% après 2000 (Chi-carré; p = 0,013). Conclusion Les BST doivent être étagées et répétées en cas d’histologie non concluante. Pour les petites lésions profondes la BST en conditions IRM est nécessaire. Pour les tumeurs pinéales, elle doit être réalisée par voie orthogonale trans-temporale.Mots-clés: Biopsie stéréotaxique, tumeur cérébrale, pinéa
Cassini Bistatic Radar Observations of Titan's Seas: Results about Dielectric Properties and Capillary Waves Detection
The Scientific Measurement System of the Gravity Recovery and Interior Laboratory (GRAIL) Mission
The Gravity Recovery and Interior Laboratory (GRAIL) mission to the Moon utilized an integrated scientific measurement system comprised of flight, ground, mission, and data system elements in order to meet the end-to-end performance required to achieve its scientific objectives. Modeling and simulation efforts were carried out early in the mission that influenced and optimized the design, implementation, and testing of these elements. Because the two prime scientific observables, range between the two spacecraft and range rates between each spacecraft and ground stations, can be affected by the performance of any element of the mission, we treated every element as part of an extended science instrument, a science system. All simulations and modeling took into account the design and configuration of each element to compute the expected performance and error budgets. In the process, scientific requirements were converted to engineering specifications that became the primary drivers for development and testing. Extensive simulations demonstrated that the scientific objectives could in most cases be met with significant margin. Errors are grouped into dynamic or kinematic sources and the largest source of non-gravitational error comes from spacecraft thermal radiation. With all error models included, the baseline solution shows that estimation of the lunar gravity field is robust against both dynamic and kinematic errors and a nominal field of degree 300 or better could be achieved according to the scaled Kaula rule for the Moon. The core signature is more sensitive to modeling errors and can be recovered with a small margin
The Transition between Telomerase and ALT Mechanisms in Hodgkin Lymphoma and Its Predictive Value in Clinical Outcomes
International audienceBackground: We analyzed telomere maintenance mechanisms (TMMs) in lymph node samples from HL patients treated with standard therapy. The TMMs correlated with clinical outcomes of patients. Materials and Methods: Lymph node biopsies obtained from 38 HL patients and 24 patients with lymphadenitis were included in this study. Seven HL cell lines were used as in vitro models. Telomerase activity (TA) was assessed by TRAP assay and verified through hTERT immunofluorescence expression; alternative telomere lengthening (ALT) was also assessed, along with EBV status. Results: Both TA and ALT mechanisms were present in HL lymph nodes. Our findings were reproduced in HL cell lines. The highest levels of TA were expressed in CD30â/CD15â cells. Small cells were identified with ALT and TA. Hodgkin and Reed Sternberg cells contained high levels of PML bodies, but had very low hTERT expression. There was a significant correlation between overall survival (p < 10â3), event-free survival (p < 10â4), and freedom from progression (p < 10â3) and the presence of an ALT profile in lymph nodes of EBV+ patients. Conclusion: The presence of both types of TMMs in HL lymph nodes and in HL cell lines has not previously been reported. TMMs correlate with the treatment outcome of EBV+ HL patients
Quantum Gas Mixtures and Dual-Species Atom Interferometry in Space
The capability to reach ultracold atomic temperatures in compact instruments
has recently been extended into space. Ultracold temperatures amplify quantum
effects, while free-fall allows further cooling and longer interactions time
with gravity - the final force without a quantum description. On Earth, these
devices have produced macroscopic quantum phenomena such as Bose-Einstein
condensation (BECs), superfluidity, and strongly interacting quantum gases.
Quantum sensors interfering the superposition of two ultracold atomic isotopes
have tested the Universality of Free Fall (UFF), a core tenet of Einstein's
classical gravitational theory, at the level. In space, cooling the
elements needed to explore the rich physics of strong interactions and
preparing the multiple species required for quantum tests of the UFF has
remained elusive. Here, utilizing upgraded capabilities of the multi-user Cold
Atom Lab (CAL) instrument within the International Space Station (ISS), we
report the first simultaneous production of a dual species Bose-Einstein
condensate in space (formed from Rb and K), observation of
interspecies interactions, as well as the production of K ultracold
gases. We have further achieved the first space-borne demonstration of
simultaneous atom interferometry with two atomic species (Rb and
K). These results are an important step towards quantum tests of UFF in
space, and will allow scientists to investigate aspects of few-body physics,
quantum chemistry, and fundamental physics in novel regimes without the
perturbing asymmetry of gravity
Global wealth disparities drive adherence to COVID-safe pathways in head and neck cancer surgery
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Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.
PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks
Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study
PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19âfree surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19âfree surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19âfree surgical pathways. Patients who underwent surgery within COVID-19âfree surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19âfree surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity scoreâmatched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19âfree surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19âfree surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks
Variation in postoperative outcomes of patients with intracranial tumors: insights from a prospective international cohort study during the COVID-19 pandemic
Background:
This study assessed the international variation in surgical neuro-oncology practice and 30-day outcomes of patients who had surgery for an intracranial tumor during the COVID-19 pandemic.
Methods:
We prospectively included adults aged â„18 years who underwent surgery for a malignant or benign intracranial tumor across 55 international hospitals from 26 countries. Each participating hospital recorded cases for 3 consecutive months from the start of the pandemic. We categorized patientsâ location by World Bank income groups (high [HIC], upper-middle [UMIC], and low- and lower-middle [LLMIC]). Main outcomes were a change from routine management, SARS-CoV-2 infection, and 30-day mortality. We used a Bayesian multilevel logistic regression stratified by hospitals and adjusted for key confounders to estimate the association between income groups and mortality.
Results:
Among 1016 patients, the number of patients in each income group was 765 (75.3%) in HIC, 142 (14.0%) in UMIC, and 109 (10.7%) in LLMIC. The management of 200 (19.8%) patients changed from usual care, most commonly delayed surgery. Within 30 days after surgery, 14 (1.4%) patients had a COVID-19 diagnosis and 39 (3.8%) patients died. In the multivariable model, LLMIC was associated with increased mortality (odds ratio 2.83, 95% credible interval 1.37â5.74) compared to HIC.
Conclusions:
The first wave of the pandemic had a significant impact on surgical decision-making. While the incidence of SARS-CoV-2 infection within 30 days after surgery was low, there was a disparity in mortality between countries and this warrants further examination to identify any modifiable factors
MAVEN ROSE Observations of the Response of the Martian Ionosphere to Dust Storms
This article also appears in: Studies of the 2018/Mars Year 34 Planet-Encircling Dust StormDuring a Martian dust storm, the lower atmosphere is heated locally. Due to dynamical effects, the upper atmosphere and ionosphere can be lifted upward on a global scale by approximately 10 km. The connections between lower atmospheric dust events and associated ionospheric responses are poorly understood due to limited observations. Here, we present MAVEN Radio Occultation Science Experiment (ROSE) observations of ionospheric peak altitude during dust events in 2018 and 2016. In June 2018, a planet-encircling dust event arose from the Acidalia storm track in the northern hemisphere. Ionospheric peak altitudes at around 20°S were normal in ROSE egress observations on 19 June and 22 June and then 10â15 km higher on 26 June and thereafter. Ionospheric peak altitudes at around 50°N were also elevated in ROSE ingress observations, which began on 17 June. This suggests that the ionospheric peak altitude was affected by the dust event in the northern hemisphere before the southern hemisphere. We also observe evidence that smaller dust storms can trigger ionospheric responses: In JulyâOctober 2016, ionospheric peak altitudes at solar zenith angles of 54â70° and latitudes of 50â80°S were 20 km higher than expected. These observations were acquired during a modest âA stormâ during a year without a global dust storm. ©2020. American Geophysical Union. All Rights Reserved.Mariner 9, MGS, and MAVEN ionospheric data used in this work are available from the NASA Planetary Data System (https://pds.nasa.gov/). MCS and THEMIS dust data are also available from this site, as well as from the Mars Climate Database website (https://www-mars.lmd.jussieu.fr/mars/dust_climatology/). The Viking ionospheric data used in this work are available from the NASA Space Science Data Coordinated Archive (https://nssdc.gsfc.nasa.gov/). M.?F. and P.?W. acknowledge support from the MAVEN project, which is funded by NASA through the Mars Exploration Program. F.G.G. is funded by the Spanish Ministerio de Ciencia, Innovaci?n y Universidades, the Agencia Estatal de Investigacion and EC FEDER funds under project RTI2018-100920-J-I00, and acknowledges financial support from the State Agency for Research of the Spanish MCIU through the ?Center of Excellence Severo Ochoa? award to the Instituto de Astrof?sica de Andaluc?a (SEV-2017-0709). Relevant output from the LMD GCM is provided as supporting information to this articlePeer reviewe
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