A dusty veil shading Betelgeuse during its Great Dimming.

Red supergiants are the most common final evolutionary stage of stars that have initial masses between 8 and 35 times that of the Sun1. During this stage, which lasts roughly 100,000 years1, red supergiants experience substantial mass loss. However, the mechanism for this mass loss is unknown2. Mass loss may affect the evolutionary path, collapse and future supernova light curve3 of a red supergiant, and its ultimate fate as either a neutron star or a black hole4. From November 2019 to March 2020, Betelgeuse-the second-closest red supergiant to Earth (roughly 220 parsecs, or 724 light years, away)5,6-experienced a historic dimming of its visible brightness. Usually having an apparent magnitude between 0.1 and 1.0, its visual brightness decreased to 1.614 ± 0.008 magnitudes around 7-13 February 20207-an event referred to as Betelgeuse's Great Dimming. Here we report high-angular-resolution observations showing that the southern hemisphere of Betelgeuse was ten times darker than usual in the visible spectrum during its Great Dimming. Observations and modelling support a scenario in which a dust clump formed recently in the vicinity of the star, owing to a local temperature decrease in a cool patch that appeared on the photosphere. The directly imaged brightness variations of Betelgeuse evolved on a timescale of weeks. Our findings suggest that a component of mass loss from red supergiants8 is inhomogeneous, linked to a very contrasted and rapidly changing photosphere.

Effects of a multifaceted intervention to promote the use of intravenous iron sucrose complex instead of ferric carboxymaltose in patients admitted for more than 24 h.

PURPOSE: Although more practical for use, the impact of ferric carboxymaltose (FCM) on the hospital budget is considerable, and intravenous iron sucrose complex (ISC) represents a cost-saving alternative for the management of iron deficiency anemia in patients during hospitalization. The Drug Committee decided to reserve FCM for day hospitalizations and contraindications to ISC, especially allergy. ISC was available for prescription for all other situations. METHODS: The impact of a multifaceted intervention promoting a switch from FCM to ISC was evaluated using an interrupted time series model with segmented regression analysis. The standardized rate of the dispensing of FCM, ISC, and oral iron by the hospital pharmacy, as well as the rate of the dispensing of packed red blood cells and the number of biological iron status measurements, was analyzed before and after the intervention. RESULTS: There was an immediate decrease in FCM consumption following the intervention, with a reduction of 88% (RR: 0.12 [CI95% 0.10 to 0.15]). Conversely, there was a large increase in ISC use (RR: 5.1 [CI95% 4.4 to 5.9]). We did not observe a prescription shift to packed red blood cells or oral iron after the intervention. The time series analysis showed the frequency of iron status testing to remain stable before and after. The direct savings for intravenous iron for 8 months were 187,417.54 €. CONCLUSION: Our intervention to lower the impact of intravenous iron therapy on the hospital budget was effective.

Test of the Einstein Equivalence Principle near the Galactic Center Supermassive Black Hole.

During its orbit around the four million solar mass black hole Sagittarius A* the star S2 experiences significant changes in gravitational potential. We use this change of potential to test one part of the Einstein equivalence principle: the local position invariance (LPI). We study the dependency of different atomic transitions on the gravitational potential to give an upper limit on violations of the LPI. This is done by separately measuring the redshift from hydrogen and helium absorption lines in the stellar spectrum during its closest approach to the black hole. For this measurement we use radial velocity data from 2015 to 2018 and combine it with the gravitational potential at the position of S2, which is calculated from the precisely known orbit of S2 around the black hole. This results in a limit on a violation of the LPI of |ß_{He}-ß_{H}|=(2.4±5.1)×10^{-2}. The variation in potential that we probe with this measurement is six magnitudes larger than possible for measurements on Earth, and a factor of 10 larger than in experiments using white dwarfs. We are therefore testing the LPI in a regime where it has not been tested before.

[Adult intramedullary gliomas]. / Tumeurs gliales intramédullaires de l'adulte : la série du rapport.

OBJECTIVES: Intramedullary gliomas are rare tumors accounting for less than 4% of all primary central nervous system tumors. The aims of this retrospective multicenter study were to assess their natural outcome as well as management. METHODS AND MATERIALS: We studied 332 patients from 1984 to 2011. Histopathological examination revealed 72% ependymomas (94% were low grade tumors), 24% astrocytomas (29% were high grade tumors), 2.4% mixed gliomas and 1.7% oligodendrogliomas. RESULTS: The mean age at diagnosis was 42.4 years for ependymomas, with male predominance, versus 39.6 years for astrocytomas. Pain was the most common initial presentation. In 20% of cases, astrocytomas were biopsied alone, but more than 80% of ependymomas had surgical resection. Radiotherapy and chemotherapy were reserved for malignant tumors, especially if they were ependymomas. The 5-year survival rate was 76.8% for astrocytomas and 94.5% for ependymomas. Histology, functional status prior to surgery, and tumor grade are among the prognostic factors. CONCLUSION: Our study showed that surgical treatment of gliomas is well codified, at least for ependymomas, but adjuvant treatment continues to play a marginal role in the management even in astrocytomas, which are infiltrative tumors.

DIABETES INSIPIDUS IN A PATIENT WITH BRONCHOGENIC CARCINOMA AND SECONDARIES TO THE HYPOTHALAMUS - CASE REPORT.

We present a middle-aged man with features of diabetes insipidus, visual and mental impairments as a result of metastases from bronchogenic carcinoma. This case is being presented because it is uncommon; high index of suspicion and the relevant imaging techniques are required for diagnosis. Surgical resection of the pituitary secondaries with post-operative chemo-radiation brought resolution of symptoms. CONCLUSION: In conclusion, hypothalamic metastases are uncommon and are often associated with compression of the pituitary gland and optic chiasma leading to diabetes insipidus, visual impairment and mental defects. MRI for diagnosis and surgical resection followed with chemoradiation lead to improvement of symptoms but mortality is high.

Surgical management of multilevel lumbar spondylolysis: a case report and review of the literature.

Multilevel lumbar spondylolysis accounts for less than 6% of the cases of lumbar spondylolysis and its treatment, as reported in the literature, has not been consistent. Fewer than ten cases presenting triple lumbar spondylosis have been published. We describe the case of a 33-year-old male presenting bilateral L3, L4, and L5 isthmic lysis with no spondylolisthesis or disc degeneration. The MRI and CT of the lumbar spine were decisive elements in the therapeutic choice and the surgical treatment performed was bilateral L3 and L4 isthmic repair via a combined anterior and posterior L5S1 approach. The clinical and radiological results were good at the last follow-up visit.

C1-C2 stabilization by Harms arthrodesis: indications, technique, complications and outcomes in a prospective 26-case series.

INTRODUCTION: C1-C2 arthrodesis is a surgical challenge due to the proximity of neurovascular structures (vertebral arteries and spinal cord) and the wide range of motion of the joint, hampering bone fusion. A variety of techniques have been successively recommended to reduce anatomic risk and improve results in terms of biomechanical stability and fusion rates. Recently, Harms described a new technique using polyaxial screws in the C1 lateral masses and C2 pedicles. MATERIAL AND METHOD: The present study reports our experience in a consecutive series of 26 patients operated on by C1-C2 arthrodesis using the Goel and Harms technique, and details technical aspects step by step. Routine systematic immediate postoperative CT and 6-month CT controlled screw positioning and assessed fusion. Follow-up was at least 1 year, except in 2 cases (10 months). RESULTS: Twenty-six patients with a mean age of 57 years were included. Indications comprised: C2 non-union (n=11), C1-C2 fracture and/or dislocation (n=11), inflammatory pathology (n=2) and tumoral pathology (n=2). The results showed the technique to be reliable (no neurovascular complications and 85% of screws with perfect positioning) and an excellent rate of fusion (100% at 6 months). CONCLUSION: Anatomic and biomechanical considerations, combined with the present clinical and radiological outcomes, indicate that Goel and Harms fusion is to be considered the first-line attitude of choice for posterior C1-C2 arthrodesis. LEVEL OF EVIDENCE: Level IV prospective study.

Lumbar-sacral fusion by a combined approach using interbody PEEK cage and posterior pedicle-screw fixation: clinical and radiological results from a prospective study.

INTRODUCTION: This prospective series evaluated the clinical and radiological results of a circumferential lumbar fusion achieved by a combined approach in one stage (anterior then posterior) using interbody PEEK cages and posterior pedicle-screw fixation. HYPOTHESIS: The combined approach in one stage is a safe and efficient technique with few complications to achieve a fusion with a satisfying clinical and radiological outcome. MATERIALS AND METHODS: Thirty-nine consecutive patients were prospectively included, with a one-year clinical and radiological minimum follow-up, from December 2008 to July 2011. All patients suffering from degenerative disc disease or low-grade isthmic spondylolisthesis requiring L5S1, L4L5 or L4S1 spinal fusions were included. Clinical outcome was assessed using VAS, ODI and Rolland-Morris scores. Radiological outcome was assessed by analyzing PI, PT, lumbar lordosis, segmental lordosis, disc height, C7/CSFD ratio on full spine radiographies and the quality of bone fusion on a CT scan at 1-year follow-up. Blood loss, surgery time and adverse events were also recorded. RESULTS: Twenty-nine patients (74%) were operated for a lumbar degenerative disc disease and 10 patients (26%) for an isthmic spondylolisthesis. Mean age was 46 (± 10.1) years old. Clinical outcome were satisfactory. VAS, ODI and Rolland-Morris scores substantially improved. Mean follow-up was 22.5 months (± 8.7). Mean surgery time was 227 min (± 41.4) for complete surgical procedure time. Mean blood loss was 308 mL (± 179.2) for total surgery. Fusion was assessed in all cases. Disc height and segmental lordosis significantly improved in postoperative. The segmental lordosis at operated level(s) increased by 8.5° (± 5) regardless of the level, and by 11.6° (± 6) for L5-S1. CONCLUSION: The combined procedure meets the requested criteria for a lumbar fusion in terms of clinical and functional results, fusion rates, and restoration of segmental lordosis. It cumulates the advantages of the anterior and posterior approach performed alone and should be considered by surgeons before realizing a lumbar fusion.

One-stage combined lumbo-sacral fusion, by anterior then posterior approach: clinical and radiological results.

INTRODUCTION: We intended to prospectively evaluate the clinical and radiological results of lumbo-sacral fusion achieved by a combined approach, anterior then posterior. MATERIAL AND METHODS: 62 patients were consecutively treated at L5-S1, L4-L5 or L4-S1 for degenerative disc disease or low-grade isthmic spondylolisthesis by combined surgery. RESULTS: Mean operative time and blood loss were 209 min and 308 ml, respectively, including the two approaches. VAS, ODI and Roland-Morris scores significantly improved postoperatively at 1 year (p < 0.005) and fusion was obtained in all cases on the CT scan at 1-year follow-up. Segmental lordosis significantly improved postoperatively (p < 0.05) with a mean gain of 10.2° at L5-S1 and 5.5° at L4-L5. CONCLUSION: The combined procedure meets the requested criteria for a lumbar fusion in terms of clinical results, functional outcomes, fusion rates while restoring segmental lordosis and disc height. It cumulates the advantages of the anterior and posterior approach performed alone, especially for L5-S1.

Intraoperative neurophysiologic monitoring in spine surgery. Developments and state of the art in France in 2011.

Intraoperative spinal cord monitoring consists in a subcontinuous evaluation of spinal cord sensory-motor functions and allows the reduction the incidence of neurological complications resulting from spinal surgery. A combination of techniques is used: somatosensory evoked potentials (SSEP), motor evoked potentials (MEP), neurogenic motor evoked potentials (NMEP), D waves, and pedicular screw testing. In absence of intraoperative neurophysiological testing, the intraoperative wake-up test is a true form of monitoring even if its latency long and its precision variable. A 2011 survey of 117 French spinal surgeons showed that only 36% had neurophysiological monitoring available (public healthcare facilities, 42%; private facilities, 27%). Monitoring can be performed by a neurophysiologist in the operating room, remotely using a network, or directly by the surgeon. Intraoperative alerts allow real-time diagnosis of impending neurological injury. Use of spinal electrodes, moved along the medullary canal, can determine the lesion level (NMEP, D waves). The response to a monitoring alert should take into account the phase of the surgical intervention and does not systematically lead to interruption of the intervention. Multimodal intraoperative monitoring, in presence of a neurophysiologist, in collaboration with the anesthesiologist, is the most reliable technique available. However, no monitoring technique can predict a delayed-onset paraplegia that appears after the end of surgery. In cases of preexisting neurological deficit, monitoring contributes little. Monitoring of the L1-L4 spinal roots also shows low reliability. Therefore, monitoring has no indication in discal and degenerative surgery of the spinal surgery. However, testing pedicular screws can be useful. All in all, thoracic and thoracolumbar vertebral deviations, with normal preoperative neurological examination are currently the essential indication for spinal cord monitoring. Its absence in this indication is a lost opportunity for the patient. If neurophysiological means are not available, intraoperative wake-up test is a minimal obligation.

The challenge of infection prevention in spine surgery: an update.

Prevention is particularly challenging in implant-associated bone and joint infection, as it could reduce the following: (1) the risk of infection in particular patient populations; (2) the risk associated with particular surgical procedures; and/or (3) the risk of infection with particular pathogen that has the ability to produce biofilm, such as staphylococci. As a consequence, it is crucial to identify: (1) host-related risk factors that may be involved in the acquisition of infection; (2) surgical procedures particularly at risk of infection; and (3) the different ways to target the most frequent pathogens involved in implant-associated spinal infection. In this article, we reviewed the data of the literature on the infection prevention in spine surgery.

The follow-up of patients with postoperative infection of the spine.

The follow-up of patients with postoperative infection of the spine required a multidisciplinary teamwork under the guidance of the spine surgeon and the infectious disease (ID) specialist. During follow-up, the spine surgeon has to ensure the absence of neurological, mechanical and implant-related complications using clinical parameters and different imaging modalities. The ID physician has to give particular attention to antimicrobial efficacy and toxicity, especially during the first weeks when patients necessitate high-dose intravenous treatment.

A new prognostic clinicopathological classification of pituitary adenomas: a multicentric case-control study of 410 patients with 8 years post-operative follow-up.

Pituitary adenomas are currently classified by histological, immunocytochemical and numerous ultrastructural characteristics lacking unequivocal prognostic correlations. We investigated the prognostic value of a new clinicopathological classification with grades based on invasion and proliferation. This retrospective multicentric case-control study comprised 410 patients who had surgery for a pituitary tumour with long-term follow-up. Using pituitary magnetic resonance imaging for diagnosis of cavernous or sphenoid sinus invasion, immunocytochemistry, markers of the cell cycle (Ki-67, mitoses) and p53, tumours were classified according to size (micro, macro and giant), type (PRL, GH, FSH/LH, ACTH and TSH) and grade (grade 1a: non-invasive, 1b: non-invasive and proliferative, 2a: invasive, 2b: invasive and proliferative, and 3: metastatic). The association between patient status at 8-year follow-up and age, sex, and classification was evaluated by two multivariate analyses assessing disease- or recurrence/progression-free status. At 8 years after surgery, 195 patients were disease-free (controls) and 215 patients were not (cases). In 125 of the cases the tumours had recurred or progressed. Analyses of disease-free and recurrence/progression-free status revealed the significant prognostic value (p < 0.001; p < 0.05) of age, tumour type, and grade across all tumour types and for each tumour type. Invasive and proliferative tumours (grade 2b) had a poor prognosis with an increased probability of tumour persistence or progression of 25- or 12-fold, respectively, as compared to non-invasive tumours (grade 1a). This new, easy to use clinicopathological classification of pituitary endocrine tumours has demonstrated its prognostic worth by strongly predicting the probability of post-operative complete remission or tumour progression and so could help clinicians choose the best post-operative therapy.

[Analysis of asbestos bodies and nude fibres in the lung parenchyma of operated lung cancers. A retrospective monocentric study of 73 cases]. / Analyse de corps asbestosiques et de fibres nues dans le parenchyme pulmonaire de cancers du poumon opérés. Étude monocentrique rétrospective de 73 cas.

We report on a study concerning a retrospective monocentric series of 73 lung cancers operated on between July 2004 and December 2009. All patients had a mineralogical analysis of a sample of lung tissue combined with an occupational questionnaire. This combination enables us to suggest a declaration of occupational exposure in almost one third of cases. We suggest that a healthy parenchymal fragment is to be obtained by biopsy routinely in cases of lung cancer surgery. The analysis should be carried out if the occupational survey does not demonstrate any evident exposure and if the patient is not known to be presenting a pleuropulmonary disease following asbestos exposure (pleural plaques and asbestosis).

How do COPD and healthy-lung patients tolerate the reduced volume ventilation strategy during OLV ventilation.

BACKGROUND: Although a strategy of tidal volume (V(t)) reduction during the one-lung ventilation (OLV) period is advised in thoracic surgery, the influence of the pre-operative respiratory status on the tolerance of this strategy remains unknown. Therefore, the aim of this study was to compare the pulmonary function between chronic obstructive pulmonary disease (COPD) and healthy-lung patients during the operative and the post-operative period. METHODS: Forty-eight patients undergoing a planned lobectomy for cancer and presenting either a healthy lung function (n=24) or a moderate COPD stage (n=24) were ventilated without external positive end-expiratory pressure (PEEP) and received 9 ml/kg V(t) during the two-lung ventilation (TLV) period, secondary reduced to 6 ml/kg during the OLV period. Lung function was assessed by peroperative gas exchange, venous admixture, respiratory mechanical parameters and post-operative spirometric measurements. RESULTS: Although the PaO(2) was superior in the healthy-lung group during the TLV, once the OLV was established, no difference was observed between the two groups. Moreover, the PaO(2)/FiO(2) was proportionally more impaired in the healthy-lung group compared with the COPD group (50 ± 13 vs. 72 ± 19% of the baseline values after exclusion and 32 ± 15 vs. 51 ± 25% after the thoracotomy, P<0.05 for each) as well as the venous admixture. In the post-operative period, a higher decrease was observed in the healthy-lung group for the forced vital capacity and the forced expiratory volume. CONCLUSIONS: Reducing V(t) to 6 ml/kg without the adjunction of external PEEP during OLV is associated with better preservation of lung function in the case of moderate COPD than in the case of healthy-lung status.

Charcot spine: two new case reports and a systematic review of 109 clinical cases from the literature.

OBJECTIVE: The goal of the present work was to report two new clinical cases on Charcot spinal arthropathy (Charcot spine) and to identify and review all cases reported in the literature since 1978. METHOD: In parallel with a description of the clinical and radiological features of two new cases, we performed a detailed literature review after searching the PubMed and Pascal databases with the following keywords "Charcot spine", "Charcot spinal arthropathy" and "neuropathic arthropathy of the spine". RESULTS: We identified 36 publications comprising a total of 109 cases of Charcot spine. Charcot spinal arthropathy generally occurs as a late complication of traumatic spine injury (17 years afterwards, on average) and predominantly affects the thoracolumbar junction. The main symptoms are pain, spinal deformity, a change in neurological status and the presence of an audible cracking noise during movement. The radiological features combine major disc and vertebral destruction associated with hypertrophic bone formation. The therapeutic indications must be discussed on a case-by-case basis, depending on the patient's neurological and general status. CONCLUSIONS: Our review emphasizes the value of regular, systematic, long-term radiological and clinical monitoring of the injured spine, in order to detect this rare but probably under-diagnosed complication.

[Assessment of efficacy of hypertonic saline - hydroxyethylstarch in haemorrhagic shock]. / Intérêt du mélange sérum salé hypertonique-hydroxyéthylamidon lors du choc hémorragique.

OBJECTIVE: Assessment of haemodynamic, respiratory and renal effects of hypertonic saline-hydroxyethyl starch (HyperHES) in critically ill-patients with hemorrhagic shock. PATIENTS AND METHODS: Seventeen mechanically ventilated patients with hemorragic shock benefiting from a cardiovascular monitoring by PiCCO device and requiring rapid volume loading. Two hundred and fifty milliliters of HyperHES were given over 5 minutes. The efficacy of volume loading was assessed by the measure of the systolic arterial pressure (SAP), cardiac index (CI), stroke volume variation (SVV) and the indexed systemic vascular resistance (iSVR). Studied parameters were assessed at baseline, 5, 30, 60 and 180 minutes after the end of HyperHES infusion. RESULTS: SAP (105 + or - 23 vs 77 + or - 10; p<0.001) and CI (4.8 + or - 1.1 vs 3.5 + or - 0.9; p<0.001) were significantly increased whereas iSVR (1175 + or - 310 vs 1501 + or - 337; p<0.01) and SVV (13 + or - 7 vs 20 + or - 5; p<0.01) were significantly decreased 5 minutes after the HyperHES infusion. Sodium (145 + or - 6 vs 136 + or - 5; p<0.001) and chloride (118 + or - 7 vs 107 + or - 6; p<0.001) were increased 5 minutes after the infusion. The PaO(2)/FiO(2) ratio as the extravascular lung water was not influenced by the infusion. The follow-up of renal parameters during the three first days (creatinemia, uremia and diuresis) did not revelead significant variations. CONCLUSION: In patients with hemorrhagic shock, the infusion of hypertonic saline (7.5%) hydroxyethyl starch association was followed by an increase in SAP, CI serum sodium and chloride concentrations. STUDY DESIGN: Prospective observational study.

[Endoscopy versus microsurgery: results in a consecutive series of nonfunctioning pituitary adenomas]. / Résultats comparés de la chirurgie endoscopique et de la microchirurgie dans une série consécutive de macroadénomes hypophysaires non fonctionnels.

Microsurgical removal of nonfunctioning pituitary adenomas (NFPAs) is often subtotal. Removing the blind spots as viewed through the microscope, endoscopic surgery may improve the quality of removal. Our purpose was to compare the results of the two techniques in a series of NFPA patients operated on by a single surgeon. Thirty-six patients with newly diagnosed NFPAs were operated on using a purely endoscopic procedure and 29 with a microsurgical technique. All patients were explored pre- and postoperatively (at 3 and 6 months and then every 12 months) by endocrine assays, ophthalmologic exam, and 3D MRI. The endocrine and ophthalmologic results as well as the quality of resection and the complications from the two techniques were compared. The follow-up duration and the mean tumor volume (higher in the microsurgical group) were the only differences observed between the two groups. Tumor height and the invasion of the cavernous sinus were not different. All patients with preoperative visual impairment in the endoscopic group improved, whereas in the microsurgical group 90.9% improved, 4.5% were stabilized, and 4.5% worsened (p=ns). Regarding anterior pituitary functions, 42.8% of the patients improved in the endoscopic group, 45.7% remained stable, and 11.4% worsened compared to, respectively, 31, 44,8, and 24.1% in the microsurgical group (p=ns). Gross total removal was achieved in 86.1% for the endoscopic group and in only 65.5% for the microsurgical group (p=0.075). Morbidity was similar in the two groups. This retrospective series showed that endoscopic surgery compared to microsurgery increases the quality of NFPA removal with similar morbidity.

Reasoning as simulation.

The theory that human cognition proceeds through mental simulations, if true, would provide a parsimonious explanation of how the mechanisms of reasoning and problem solving integrate with and develop from mechanisms underlying forms of cognition that occur earlier in evolution and development. However, questions remain about whether simulation mechanisms are powerful enough to exhibit human-level reasoning and inference. In order to investigate this issue, we show that it is possible to characterize some of the most powerful modern artificial intelligence algorithms for logical and probabilistic inference as methods of simulating alternate states of the world. We show that a set of specific human perceptual mechanisms, even if not implemented using mechanisms described in artificial intelligence, can nevertheless perform the same operations as those algorithms. Although this result does not demonstrate that simulation theory is true, it does show that whatever mechanisms underlie perception have at least as much power to explain non-perceptual human reasoning and problem solving as some of the most powerful known algorithms.