Techniques d’imagerie fonctionnelle du système respiratoire par tomographie d’impédance électrique

RÉSUMÉ Les maladies liées au système respiratoire ont un impact socio-économique très important. Par exemple, en 2008, le taux de mortalité mondiale causée par les tumeurs malignes, les infections et les maladies de l’appareil respiratoire a été de 15 %. Ces dernières comprennent des maladies caractérisées par des rapports ventilation/perfusion faibles, comme l’asthme, l’oedème pulmonaire, le syndrome de détresse respiratoire aiguë et la bronchite chronique et également des maladies caractérisées par des rapports ventilation/perfusion élevées comme l’emphysème, l’embolie pulmonaire et la broncho-pneumopathie chronique obstructive. En raison du large spectre d’anomalies respiratoires, le développement de nouvelles méthodes et d’instruments pour le monitorage du système respiratoire et le diagnostic des maladies qui lui sont associées demeure très pertinent. Un exemple de ces nouveaux instruments est le système de tomographie d’impédance électrique (TIE), développé à l’Institut de Génie Biomédical (IGB) de l’École Polytechnique de Montréal. La TIE est une technique qui permet d’obtenir l’image de la distribution spatio-temporelle des propriétés électriques des tissus biologiques impliqués dans l’activité cardio respiratoire. L’acquisition de données de TIE s’effectue au moyen d’électrodes que l’on fixe sur le pourtour du thorax. Ces électrodes servent à appliquer un courant sinusoïdal de faible amplitude et à mesurer les différences de potentiel qui résultent du passage du courant dans les tissus du thorax. Un algorithme de reconstruction permet de traiter ces données pour produire des images de la distribution de conductivité électrique. La TIE est donc une technique non invasive que l’on peut utiliser pour le monitorage de longue durée de patients. Les systèmes de TIE sont sécuritaires, compacts, et peu coûteux à l’achat et en frais d’opération. En contraste, d’autres techniques d’imagerie médicale, comme la scintigraphie et la tomodensitographie, requièrent des appareils coûteux et encombrants qui comportent l’administration de substances radioactives ou encore l’exposition aux rayons X. L’interprétation des images de TIE est toutefois difficile en raison de leur faible résolution spatiale et de la superposition de différents phénomènes physiologiques. L’objectif du projet exposé dans ce mémoire est de repousser ces limites en mettant en oeuvre des techniques d’imagerie fonctionnelle qui permettent d’extraire des informations d’intérêt clinique.----------ABSTRACT Respiratory diseases have a significant socio-economic impact. For example, in 2008, the global mortality rate caused by malignant neoplasms, infections, and respiratory pathologies was 15%. These include pathologies characterized by a low ventilation/perfusion ratio, such as asthma, pulmonary edema, acute respiratory distress syndrome, and chronic bronchitis; and those characterized by a high ventilation/perfusion ratio such as emphysema, pulmonary embolism and chronic obstructive pulmonary disease. Because of the wide spectrum of respiratory pathologies, the development of new methods and instruments for monitoring the respiratory system and assist clinicians in the diagnosis and treatment of these diseases remains highly relevant. An example of these new instruments is the electrical impedance tomography (EIT) system developed by the Institut de Génie Biomédical (IGB) of École Polytechnique de Montréal. EIT is a technique that allows imaging the spatio-temporal changes in electrical properties of biological tissues involved in cardiac and respiratory activity. Acquisition of EIT data is done by means of electrodes positioned on the periphery of the thorax. These electrodes are used to apply a small sinusoidal current and to measure potential differences arising from the flow of the applied current through the thoracic tissues. A reconstruction algorithm processes the data to produce images of the electrical conductivity distribution. EIT is therefore a non-invasive technique that can be used for long term patient monitoring. EIT systems are safe, compact and involve low initial investment and operating costs. By contrast, other medical imaging techniques such as scintigraphy and tomodensitography require systems that are very expensive, bulky and involve the administration of radioactive compounds or exposure to X-rays. The interpretation of EIT images is however difficult, due to the low spatial resolution and the superposition of effects from different physiological processes. The objective of the project described in this dissertation is to overcome these limitations by implementing functional imaging techniques that allow extracting clinically significant information. Our work is based on functional imaging techniques described in the scientific literature that have been validated by off-line data processing. We believe that these techniques will achieve a significant impact only if they can be executed in real time, so that the information they provid

The Phenotypic Characterization of the Cammalleri Sisters, an Example of Exceptional Longevity

This article shows demographic, clinical, anamnestic, cognitive, and functional data as well as biochemical, genetic, and epigenetic parameters of two exceptional siblings: Diega (supercentenarian) and Filippa (semisupercentenarian) Cammalleri. The purpose of this study is to provide new insights into the extreme phenotypes represented by semisupercentenarians and supercentenarians. Different studies have been published on supercentenarians, but to the best of our knowledge, this is the only concerning two sisters and the most detailed from a phenotypic point of view. Our findings agree with the suggestion that supercentenarians have an increasing relative resistance to age-related diseases, approximating the limits of the functional human reserve to address successfully the acute causes of death. More interestingly, our data agree with, and extend, the suggestion that inflammation and oxidative stress predict centenarian mortality

Kinetic Phenomena in Thin Film Electronic Materials

Contains reports on twelve research projects.National Science Foundation (Grant ECS 85-06505)U.S. Air Force - Office of Scientific Research (Contract AFOSR-85-0154)Semiconductor Research Corporation (Contract 87-SP-080)National Science Foundation (Grant ECS 85-06565)International Business Machines, Inc.Sony International Business Machines, Inc.National Science Foundation (Grant DMR 84-18718)International Business Machines, Thomas J. Watson Research CenterJoint Services Electronics Program (Contract DAALO3-86-K-0002)National Science Foundation (Grant DMR 85-06030)Charles Stark Draper Laboratory (Contract DL-H-261827)Nippon Telegraph and Telephone, Inc

Microstructural Evolution in Thin Films of Electronic Materials

Contains reports on eight research projects.National Science Foundation (Grant ECS 85-06565)U.S. Air Force - Office of Scientific Research (Contract AFOSR 85-0154)National Science Foundation-Materials Research Laboratory(Grant DMR 81-19285)National Science Foundation (Grant DMR 85-06030)International Business Machines, Inc. Faculty Development AwardMitsui Career Development AwardInternational Business Machines, Inc.Semiconductor Research Corporation (Contract 86-05-080)Joint Services Electronics Program (Contract DAAG-29-83-K-0003)Charles Stark Draper LaboratoryDefense Advanced Research Projects Agency (DARPA)Nippon Telegraph and Telephone, Inc

Colorectal Cancer Stage at Diagnosis Before vs During the COVID-19 Pandemic in Italy

IMPORTANCE Delays in screening programs and the reluctance of patients to seek medical attention because of the outbreak of SARS-CoV-2 could be associated with the risk of more advanced colorectal cancers at diagnosis. OBJECTIVE To evaluate whether the SARS-CoV-2 pandemic was associated with more advanced oncologic stage and change in clinical presentation for patients with colorectal cancer. DESIGN, SETTING, AND PARTICIPANTS This retrospective, multicenter cohort study included all 17 938 adult patients who underwent surgery for colorectal cancer from March 1, 2020, to December 31, 2021 (pandemic period), and from January 1, 2018, to February 29, 2020 (prepandemic period), in 81 participating centers in Italy, including tertiary centers and community hospitals. Follow-up was 30 days from surgery. EXPOSURES Any type of surgical procedure for colorectal cancer, including explorative surgery, palliative procedures, and atypical or segmental resections. MAIN OUTCOMES AND MEASURES The primary outcome was advanced stage of colorectal cancer at diagnosis. Secondary outcomes were distant metastasis, T4 stage, aggressive biology (defined as cancer with at least 1 of the following characteristics: signet ring cells, mucinous tumor, budding, lymphovascular invasion, perineural invasion, and lymphangitis), stenotic lesion, emergency surgery, and palliative surgery. The independent association between the pandemic period and the outcomes was assessed using multivariate random-effects logistic regression, with hospital as the cluster variable. RESULTS A total of 17 938 patients (10 007 men [55.8%]; mean [SD] age, 70.6 [12.2] years) underwent surgery for colorectal cancer: 7796 (43.5%) during the pandemic period and 10 142 (56.5%) during the prepandemic period. Logistic regression indicated that the pandemic period was significantly associated with an increased rate of advanced-stage colorectal cancer (odds ratio [OR], 1.07; 95%CI, 1.01-1.13; P = .03), aggressive biology (OR, 1.32; 95%CI, 1.15-1.53; P < .001), and stenotic lesions (OR, 1.15; 95%CI, 1.01-1.31; P = .03). CONCLUSIONS AND RELEVANCE This cohort study suggests a significant association between the SARS-CoV-2 pandemic and the risk of a more advanced oncologic stage at diagnosis among patients undergoing surgery for colorectal cancer and might indicate a potential reduction of survival for these patients

Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition)

The third edition of Flow Cytometry Guidelines provides the key aspects to consider when performing flow cytometry experiments and includes comprehensive sections describing phenotypes and functional assays of all major human and murine immune cell subsets. Notably, the Guidelines contain helpful tables highlighting phenotypes and key differences between human and murine cells. Another useful feature of this edition is the flow cytometry analysis of clinical samples with examples of flow cytometry applications in the context of autoimmune diseases, cancers as well as acute and chronic infectious diseases. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid. All sections are written and peer‐reviewed by leading flow cytometry experts and immunologists, making this edition an essential and state‐of‐the‐art handbook for basic and clinical researchers.DFG, 389687267, Kompartimentalisierung, Aufrechterhaltung und Reaktivierung humaner Gedächtnis-T-Lymphozyten aus Knochenmark und peripherem BlutDFG, 80750187, SFB 841: Leberentzündungen: Infektion, Immunregulation und KonsequenzenEC/H2020/800924/EU/International Cancer Research Fellowships - 2/iCARE-2DFG, 252623821, Die Rolle von follikulären T-Helferzellen in T-Helferzell-Differenzierung, Funktion und PlastizitätDFG, 390873048, EXC 2151: ImmunoSensation2 - the immune sensory syste

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Doubly-balanced Gilbert Cell Down-conversion Mixer in AMS 0.35 um SiGe CMOS for Mode-1 MB-OFDM UWB Receivers

This work presents the design of a mixer in RF CMOS technology for a MB-OFDM UWB band transceiver operating in Mode-1 (3.1–4.8 GHz). Working at circuit-level in ADSTM RF CAD and at system-level in Matlab-SimulinkTM, a Gilbert cell architecture is proposed, exploiting current bleeding, integrated matching and inductive tuning techniques. Circuit performance results in AMS 0.35 μm SiGe CMOS technology prove the feasibility of the circuit for integration in a low-cost UWB receiver