How does obstructive sleep apnea alter cerebral hemodynamics?

STUDY OBJECTIVES: We aimed to characterize the cerebral hemodynamic response to obstructive sleep apnea/hypopnea events, and evaluate their association to polysomnographic parameters. The characterization of the cerebral hemodynamics in obstructive sleep apnea (OSA) may add complementary information to further the understanding of the severity of the syndrome beyond the conventional polysomnography. METHODS: Severe OSA patients were studied during night sleep while monitored by polysomnography. Transcranial, bed-side diffuse correlation spectroscopy (DCS) and frequency-domain near-infrared diffuse correlation spectroscopy (NIRS-DOS) were used to follow microvascular cerebral hemodynamics in the frontal lobes of the cerebral cortex. Changes in cerebral blood flow (CBF), total hemoglobin concentration (THC), and cerebral blood oxygen saturation (StO2) were analyzed. RESULTS: We considered 3283 obstructive apnea/hypopnea events from sixteen OSA patients (Age (median, interquartile range) 57 (52-64.5); females 25%; AHI (apnea-hypopnea index) 84.4 (76.1-93.7)). A biphasic response (maximum/minimum followed by a minimum/maximum) was observed for each cerebral hemodynamic variable (CBF, THC, StO2), heart rate and peripheral arterial oxygen saturation (SpO2). Changes of the StO2 followed the dynamics of the SpO2, and were out of phase from the THC and CBF. Longer events were associated with larger CBF changes, faster responses and slower recoveries. Moreover, the extrema of the response to obstructive hypopneas were lower compared to apneas (p < .001). CONCLUSIONS: Obstructive apneas/hypopneas cause profound, periodic changes in cerebral hemodynamics, including periods of hyper- and hypo-perfusion and intermittent cerebral hypoxia. The duration of the events is a strong determinant of the cerebral hemodynamic response, which is more pronounced in apnea than hypopnea events.

Transcranial, Non-Invasive Evaluation of Potential Misery Perfusion During Hyperventilation Therapy of Traumatic Brain Injury Patients.

Hyperventilation (HV) therapy uses vasoconstriction to reduce intracranial pressure (ICP) by reducing cerebral blood volume. However, as HV also lowers cerebral blood flow (CBF), it may provoke misery perfusion (MP), in which the decrease in CBF is coupled with increased oxygen extraction fraction (OEF). MP may rapidly lead to the exhaustion of brain energy metabolites, making the brain vulnerable to ischemia. MP is difficult to detect at the bedside, which is where transcranial hybrid, near-infrared spectroscopies are promising because they non-invasively measure OEF and CBF. We have tested this technology during HV (∼30 min) with bilateral, frontal lobe monitoring to assess MP in 27 sessions in 18 patients with traumatic brain injury. In this study, HV did not lead to MP at a group level (p > 0.05). However, a statistical approach yielded 89 events with a high probability of MP in 19 sessions. We have characterized each statistically significant event in detail and its possible relationship to clinical and radiological status (decompressive craniectomy and presence of a cerebral lesion), without detecting any statistically significant difference (p > 0.05). However, MP detection stresses the need for personalized, real-time assessment in future clinical trials with HV, in order to provide an optimal evaluation of the risk-benefit balance of HV. Our study provides pilot data demonstrating that bedside transcranial hybrid near-infrared spectroscopies could be utilized to assess potential MP.

Comparison of cerebral metabolic rate of oxygen, blood flow, and bispectral index under general anesthesia.

Significance: The optical measurement of cerebral oxygen metabolism was evaluated. Aim: Compare optically derived cerebral signals to the electroencephalographic bispectral index (BIS) sensors to monitor propofol-induced anesthesia during surgery. Approach: Relative cerebral metabolic rate of oxygen ( rCMRO 2 ) and blood flow (rCBF) were measured by time-resolved and diffuse correlation spectroscopies. Changes were tested against the relative BIS (rBIS) ones. The synchronism in the changes was also assessed by the R-Pearson correlation. Results: In 23 measurements, optically derived signals showed significant changes in agreement with rBIS: during propofol induction, rBIS decreased by 67% [interquartile ranges (IQR) 62% to 71%], rCMRO 2 by 33% (IQR 18% to 46%), and rCBF by 28% (IQR 10% to 37%). During recovery, a significant increase was observed for rBIS (48%, IQR 38% to 55%), rCMRO 2 (29%, IQR 17% to 39%), and rCBF (30%, IQR 10% to 44%). The significance and direction of the changes subject-by-subject were tested: the coupling between the rBIS, rCMRO 2 , and rCBF was witnessed in the majority of the cases (14/18 and 12/18 for rCBF and 19/21 and 13/18 for rCMRO 2 in the initial and final part, respectively). These changes were also correlated in time ( R > 0.69 to R = 1 , p - values < 0.05 ). Conclusions: Optics can reliably monitor rCMRO 2 in such conditions.

High frequency of acute decompensation and cancer in patients with compensated cirrhosis due to nonalcoholic fatty liver disease: A retrospective cohort study.

The natural history of compensated cirrhosis due to nonalcoholic fatty liver disease (NAFLD) has not been completely characterized. The aim of the present study was to assess the incidence and risk factors of acute decompensation of cirrhosis, hepatocellular carcinoma, and extrahepatic cancers. This was a multicenter, retrospective, cohort study including 449 patients with compensated cirrhosis due to NAFLD. We calculated cumulative incidences and used competitive risk analysis to determine the risk factors associated with decompensation and cancer development. Over a median of 39 months of follow-up, 124 patients (28%) presented acute decompensation. The most frequent decompensation was ascites (21%) followed by hepatic encephalopathy (15%), variceal bleeding (9%), and spontaneous bacterial peritonitis (3%). Acute-on-chronic liver failure was diagnosed in 6% of patients during follow-up. Liver function parameters and specifically an albumin level below 40 g/L were independently associated with an increased risk of decompensation. The presence of ischemic heart disease was independently associated with acute decompensation. Seventy-eight patients (18%) developed hepatocellular carcinoma or extrahepatic cancers during follow-up (51 and 27, respectively). Conclusion: Patients with compensated cirrhosis due to NAFLD are at high risk of severe liver complications, such as the development of acute decompensation, in a relative short follow-up time. This population is at high risk of hepatic and extrahepatic cancers.

Chronic hypogammaglobulinemia after allogeneic stem cell transplantation and their treatment with subcutaneous immunoglobulin in pediatric patients.

INTRODUCTION: Hypogammaglobulinemia in the first months after allogeneic hematopoietic stem cell transplantation (HSCT) is common in paediatric patients. During this phase, replacement therapy with human immunoglobulin must be administered parenterally to prevent infections. In some cases, this hypogammaglobulinemia persists over time, which forces further treatment when the patient is usually no longer a carrier of a central line, making them ideal candidates for subcutaneous replacement therapy. There is little published literature describing the use of this method in paediatric patients undergoing HSCT, widely described in replacement treatment in children with primary immunodeficiencies with very good results. PATIENTS AND METHODS: An observational, descriptive, longitudinal and retrospective study is carried out. During the years 2008-2019, we evaluated all paediatric patients undergoing HSCT in our center with persistent chronic hypogammaglobulinemia (for over a year). The treatment phase with intravenous immunoglobulin (Privigen®) and the first four years of treatment with subcutaneous immunoglobulin (Hizentra®) are evaluated using a questionnaire. RESULTS: During the years 2008-2019, 175 patients underwent HSCT, 143 (82%) of whom exceeded three months after transplantation. Three (2%) of them had persistent hypogammaglobulinemia. All three share factors described in the literature involved in immune reconstitution. After analysing the questionnaire, it is observed that switching from intravenous to subcutaneous gammaglobulin has involved a great improvement in their quality of life. CONCLUSIONS: The origin of chronic hypogammaglobulinemia in our patients shows different factors and cannot be attributed to a single cause. Due to the limited number of patients no conclusions can be drawn at the population level. We have been able to observe that replacement treatment with Hizentra 20% has been as effective as the intravenous administration without evidence of an increase in bacterial infections. Furthermore, it has also led to an improvement in quality of life and increased comfort, as the patients themselves have stated.

Experience of the Spanish Group for Hematopoietic Transplantation (GETMON-GETH) in allogenic Hematopoietic stem cell Transplantation in Philadelphia acute lymphoblastic leukemia.

INTRODUCTION: Outcomes in patients diagnosed of acute lymphoblastic leukemia with Philadelphia chromosome (Ph-ALL) remains unfavourable compared to other subtypes of acute lymphoblastic leukemia despite improvements in drug treatments as well as advances in hematopoietic stem cell transplantation (HSCT). PATIENTS AND METHODS: The role of allogeneic HSCT in Ph-ALL patients has been analysed through a multicentric study where data belonging to 70 patients diagnosed of this entity in different centers that received HSCT between years 1998 and 2014, were reported by the Grupo Español de Trasplante Hematopoyético (GETH). RESULTS: The performance of HSCT from year 2004, in first complete remission (CR) status with thymoglobulin (ATG) based conditioning had a favorable impact on overall survival (OS). HSTC performance from year 2004, in first CR with ATG-based conditioning in addition to acute graft versus host disease (aGvHD) development, increased event free survival (EFS). Treatment with imatinib as well as undetectable minimal residual disease (MRD) prior to HSCT, combined with aGvHD, reduced risk of relapse (RR). Patient age less than 10 years when HSCT, first CR and ATG-based conditioning were associated to a lower transplant related mortality (TRM). CONCLUSIONS: Patients that could achieve first CR that also received ATG-based conditioning had a better OS and EFS, so HSCT should be considered for this group of patients.

Environmental heterogeneity in human health studies. A compositional methodology for Land Use and Land cover data.

The use of Land use and Land cover (LULC) data is gradually becoming more widely spread in studies relating the environment to human health. However, little research has acknowledged the compositional nature of these data. The goal of the present study is to explore, for the first time, the independent effect of eight LULC categories (agricultural land, bare land, coniferous forest, broad-leaved forest, sclerophyll forest, grassland and shrubs, urban areas, and waterbodies) on three selected common health conditions: type 2 diabetes mellitus (T2DM), asthma and anxiety, using a compositional methodological approach and leveraging observational health data of Catalonia (Spain) at area level. We fixed the risk exposure scenario using three covariates (socioeconomic status, age group, and sex). Then, we assessed the independent effect of the eight LULC categories on each health condition. Our results show that each LULC category has a distinctive effect on the three health conditions and that the three covariates clearly modify this effect. This compositional approach has yielded plausible results supported by the existing literature, highlighting the relevance of environmental heterogeneity in health studies. In this sense, we argue that different types of environment possess exclusive biotic and abiotic elements affecting distinctively on human health. We believe our contribution might help researchers approach the environment in a more multidimensional manner integrating environmental heterogeneity in the analysis.

Community Risk Factors in the COVID-19 Incidence and Mortality in Catalonia (Spain). A Population-Based Study.

The heterogenous distribution of both COVID-19 incidence and mortality in Catalonia (Spain) during the firsts moths of the pandemic suggests that differences in baseline risk factors across regions might play a relevant role in modulating the outcome of the pandemic. This paper investigates the associations between both COVID-19 incidence and mortality and air pollutant concentration levels, and screens the potential effect of the type of agri-food industry and the overall land use and cover (LULC) at area level. We used a main model with demographic, socioeconomic and comorbidity covariates highlighted in previous research as important predictors. This allowed us to take a glimpse of the independent effect of the explanatory variables when controlled for the main model covariates. Our findings are aligned with previous research showing that the baseline features of the regions in terms of general health status, pollutant concentration levels (here NO2 and PM10), type of agri-food industry, and type of land use and land cover have modulated the impact of COVID-19 at a regional scale. This study is among the first to explore the associations between COVID-19 and the type of agri-food industry and LULC data using a population-based approach. The results of this paper might serve as the basis to develop new research hypotheses using a more comprehensive approach, highlighting the inequalities of regions in terms of risk factors and their response to COVID-19, as well as fostering public policies towards more resilient and safer environments.

[Experience of the Spanish Group for Hematopoietic Transplantation (GETMON-GETH) in allogenic hematopoietic stem cell transplantation in Philadelphia acute lymphoblastic leukemia]. / Experiencia del Grupo Español de Trasplante Hematopoyético (GETMON-GETH) en el trasplante alogénico de progenitores hematopoyéticos en leucemia aguda linfoblástica Philadelphia.

INTRODUCTION: Outcomes in patients diagnosed of acute lymphoblastic leukemia with Philadelphia chromosome (Ph-ALL) remains unfavourable compared to other subtypes of acute lymphoblastic leukemia despite improvements in drug treatments as well as advances in hematopoietic stem cell transplantation (HSCT). PATIENTS AND METHODS: The role of allogeneic HSCT in Ph-ALL patients has been analysed through a multicentric study where data belonging to 70 patients diagnosed of this entity in different center that received HSCT between years 1998 and 2014, were reported by the Grupo Español de Trasplante Hematopoyético (GETH). RESULTS: The performance of HSCT from year 2004, in first complete remission (CR) status with thymoglobulin (ATG) based conditioning had a favorable impact on overall survival (OS). HSTC performance from year 2004, in first CR with ATG-based conditioning in addition to acute graft versus host disease (aGvHD) development, increased event free survival (EFS). Treatment with imatinib as well as undetectable minimal residual disease (MRD) prior to HSCT, combined with aGvHD, reduced risk of relapse (RR). Patient age less than 10 years when HSCT, first CR and ATG-based conditioning were associated to a lower transplant related mortality (TRM). CONCLUSIONS: Patients that could achieve first CR that also received ATG-based conditioning had a better OS and EFS, so HSCT should be considered for this group of patients.

Surgical reconstitution of the perineum after delivery: a qualitative study of a pedagogical practice. / Reconstituição cirúrgica do períneo após o parto: um estudo qualitativo de uma prática pedagógica.

A pedagogical activity with Master's Degree and Postgraduate students in Maternal Health and Obstetrics Nursing is described, applying principles of simulated practice in perineal suturing after delivery. This procedure causes a lot of insecurity and generates great anxiety in the students, when they start the internship in a delivery room. OBJECTIVES: to develop the psychomotor skills in students for perineal surgical reconstruction; increase students' self-confidence to perform the procedure. METHODOLOGY: qualitative, with 2 moments of data collection applied to two courses. Questionnaire with open questions, focus group session and filming. Content analysis of the answers to the questions and verbatim of the focus group. RESULTS: a close relationship was observed between simulation and skills development. CONCLUSION: the students emphasized the importance of the pedagogical activity in the acquisition of suturing skills, improving their self-confidence and reducing the initial anxiety. The use of the qualitative research allowed identifying the impact of the simulated practice on the development of the students' skills and to identify aspects to be improved, contributing to the progress of pedagogical practices.

Descreve-se uma atividade pedagógica com estudantes do Mestrado e Pós-Licenciatura em Enfermagem de Saúde Materna e Obstetrícia, aplicando princípios da prática simulada na realização da sutura perineal após o parto. Este procedimento causa muita insegurança e gera grande ansiedade nos estudantes, quando iniciam estágio em bloco de partos. Os objetivos deste artigo são desenvolver competências psicomotoras nos estudantes para a reconstituição cirúrgica perineal; aumentar a autoconfiança dos estudantes para o procedimento. Metodologia qualitativa, com 2 momentos de recolha de dados aplicados a dois cursos. Questionário com perguntas abertas, sessão de "focus group" e filmagem. Análise de conteúdo das respostas às perguntas abertas e verbatim do "focus group". Como Resultados destaca-se uma estreita relação entre a simulação e o desenvolvimento de competências. Os estudantes salientaram a importância da atividade pedagógica na aquisição de competências de sutura, reforço da autoconfiança e na diminuição da ansiedade inicial. O uso da investigação qualitativa permitiu identificar o impacto da prática simulada no desenvolvimento de competências dos estudantes, identificar aspetos a aperfeiçoar na metodologia, contribuindo para a melhoria das práticas pedagógicas.

Reconstituição cirúrgica do períneo após o parto: um estudo qualitativo de uma prática pedagógica / Surgical reconstitution of the perineum after delivery: a qualitative study of a pedagogical practice

Resumo Descreve-se uma atividade pedagógica com estudantes do Mestrado e Pós-Licenciatura em Enfermagem de Saúde Materna e Obstetrícia, aplicando princípios da prática simulada na realização da sutura perineal após o parto. Este procedimento causa muita insegurança e gera grande ansiedade nos estudantes, quando iniciam estágio em bloco de partos. Os objetivos deste artigo são desenvolver competências psicomotoras nos estudantes para a reconstituição cirúrgica perineal; aumentar a autoconfiança dos estudantes para o procedimento. Metodologia qualitativa, com 2 momentos de recolha de dados aplicados a dois cursos. Questionário com perguntas abertas, sessão de "focus group" e filmagem. Análise de conteúdo das respostas às perguntas abertas e verbatim do "focus group". Como Resultados destaca-se uma estreita relação entre a simulação e o desenvolvimento de competências. Os estudantes salientaram a importância da atividade pedagógica na aquisição de competências de sutura, reforço da autoconfiança e na diminuição da ansiedade inicial. O uso da investigação qualitativa permitiu identificar o impacto da prática simulada no desenvolvimento de competências dos estudantes, identificar aspetos a aperfeiçoar na metodologia, contribuindo para a melhoria das práticas pedagógicas.

Abstract A pedagogical activity with Master's Degree and Postgraduate students in Maternal Health and Obstetrics Nursing is described, applying principles of simulated practice in perineal suturing after delivery. This procedure causes a lot of insecurity and generates great anxiety in the students, when they start the internship in a delivery room. Objectives: to develop the psychomotor skills in students for perineal surgical reconstruction; increase students' self-confidence to perform the procedure. Methodology: qualitative, with 2 moments of data collection applied to two courses. Questionnaire with open questions, focus group session and filming. Content analysis of the answers to the questions and verbatim of the focus group. Results: a close relationship was observed between simulation and skills development. Conclusion: the students emphasized the importance of the pedagogical activity in the acquisition of suturing skills, improving their self-confidence and reducing the initial anxiety. The use of the qualitative research allowed identifying the impact of the simulated practice on the development of the students' skills and to identify aspects to be improved, contributing to the progress of pedagogical practices.

Reviewing the reliability of Land Use and Land Cover data in studies relating human health to the environment.

BACKGROUND: In recent years, research has been increasingly devoted to understanding the complex human health-environment relationship. Nevertheless, many different measurements have been applied to characterize the environment. Among them, the application of Land Use and Land Cover (LULC) data is becoming more noticeable over time. AIMS: This research aims to analyse the reliability of Land Use and Land Cover data (LULC) data as a suitable describer of the environment in studies relating human health to the environment. With a specific focus on the methodologies using LULC data, we also examine the study designs and analytical methods that have been commonly performed so far. MATERIALS AND METHODS: We gathered studies relating human health outcomes to Land Use and Land Cover (LULC) data. A Boolean search limited to reviews was conducted in February 2019 using Web of Science Core Collection search engines. Five reviews were selected as our preliminary starting set of literature and from those, two backward snowballing searches were conducted. The first backward snowballing search used the reference lists of the first 5 reviews and revealed 17 articles. From these, the second search gathered 24 new articles also fulfilling the inclusion criteria established. In total, 41 articles were examined. RESULTS: Our main results reported that Land Use and Land Cover (LULC) data national level data was preferred over LULC international level data. However, this tendency seems to be strongly related to the specific aims of the articles. They essentially defined the living environment either through buffer zones, using the administrative boundaries wherein the individuals reside, or using the specific location of the individuals assessed. As for the characterization of the environment, authors performed 4 principal methodologies: extracting the percentage of green space, computing the "Land Use mix", recording the type of land cover, and using the percentage of tree canopy. Besides, all the articles included measurements in urban contexts and most of them evaluated the accessibility of individuals to their surroundings. Furthermore, it was clearly stated that the complexity of the topic and the challenging data leads authors to carry out advanced statistical methods and mostly cross-sectional designs with no causal relations. DISCUSSION AND CONCLUSIONS: Land Use and Land Cover (LULC) data has been demonstrated to be a versatile tool supporting both local-focused studies with few individuals involved and broad territorial-scoped studies with huge populations. Promising synergy has been highlighted between Electronic Health Records (EHR) and LULC data in studies dealing with massive information and broader scopes with regards to the assessment of territorial realities. As this emerging topic matures, investigators should (1) elucidate subjects of ongoing debate such as the measurement of the living environment and its characterization; (2) explore the whole potential of LULC data, using methodologies that encompass both their biophysical and socioeconomic information; (3) perform innovative designs that are able to establish causal relationships among the studied variables (for example, Cellular Automata models), and (4) expand the current set of studied health outcomes leveraging comprehensive and trustworthy health data sources such as EHR.

Distinct flavors of Zipf's law and its maximum likelihood fitting: Rank-size and size-distribution representations.

In recent years, researchers have realized the difficulties of fitting power-law distributions properly. These difficulties are higher in Zipfian systems, due to the discreteness of the variables and to the existence of two representations for these systems, i.e., two versions depending on the random variable to fit: rank or size. The discreteness implies that a power law in one of the representations is not a power law in the other, and vice versa. We generate synthetic power laws in both representations and apply a state-of-the-art fitting method to each of the two random variables. The method (based on maximum likelihood plus a goodness-of-fit test) does not fit the whole distribution but the tail, understood as the part of a distribution above a cutoff that separates non-power-law behavior from power-law behavior. We find that, no matter which random variable is power-law distributed, using the rank as the random variable is problematic for fitting, in general (although it may work in some limit cases). One of the difficulties comes from recovering the "hidden" true ranks from the empirical ranks. On the contrary, the representation in terms of the distribution of sizes allows one to recover the true exponent (with some small bias when the underlying size distribution is a power law only asymptotically).

The Brevity Law as a Scaling Law, and a Possible Origin of Zipf's Law for Word Frequencies.

An important body of quantitative linguistics is constituted by a series of statistical laws about language usage. Despite the importance of these linguistic laws, some of them are poorly formulated, and, more importantly, there is no unified framework that encompasses all them. This paper presents a new perspective to establish a connection between different statistical linguistic laws. Characterizing each word type by two random variables-length (in number of characters) and absolute frequency-we show that the corresponding bivariate joint probability distribution shows a rich and precise phenomenology, with the type-length and the type-frequency distributions as its two marginals, and the conditional distribution of frequency at fixed length providing a clear formulation for the brevity-frequency phenomenon. The type-length distribution turns out to be well fitted by a gamma distribution (much better than with the previously proposed lognormal), and the conditional frequency distributions at fixed length display power-law-decay behavior with a fixed exponent α ≃ 1.4 and a characteristic-frequency crossover that scales as an inverse power δ ≃ 2.8 of length, which implies the fulfillment of a scaling law analogous to those found in the thermodynamics of critical phenomena. As a by-product, we find a possible model-free explanation for the origin of Zipf's law, which should arise as a mixture of conditional frequency distributions governed by the crossover length-dependent frequency.

Executive Summary of the Consensus Document on the Diagnosis and Management of Patients with Primary Immunodeficiencies.

Primary immunodeficiencies (PIDs) are rare, undiagnosed and potentially fatal diseases. Clinical manifestations of PID can be fatal or leave sequelae that worsen the quality of life of patients. Traditionally, the treatment of PIDs has been largely supportive, with the exception of bone marrow transplantation and, more recently, gene therapy. The discovering of new affected pathways, the development of new molecules and biologics, and the increasing understanding of the molecular basis of these disorders have created opportunities in PIDs therapy. This document aims to review current knowledge and to provide recommendations about the diagnosis and clinical management of adults and children with PIDs based on the available scientific evidence taking in to account current practice and future challenges. A systematic review was conducted, and evidence levels based on the available literature are given for each recommendation where available.

Executive Summary of the Consensus Document on the Diagnosis and Management of Patients with Primary Immunodeficiencies.

Primary immunodeficiencies (PIDs) are rare, undiagnosed and potentially fatal diseases. Clinical manifestations of PID can be fatal or leave sequelae that worsen the quality of life of patients. Traditionally, the treatment of PIDs has been largely supportive, with the exception of bone marrow transplantation and, more recently, gene therapy. The discovering of new affected pathways, the development of new molecules and biologics, and the increasing understanding of the molecular basis of these disorders have created opportunities in PIDs therapy. This document aims to review current knowledge and to provide recommendations about the diagnosis and clinical management of adults and children with PIDs based on the available scientific evidence taking in to account current practice and future challenges. A systematic review was conducted, and evidence levels based on the available literature are given for each recommendation where available.

Reactivation of SARS-CoV-2 after Asymptomatic Infection while on High-Dose Corticosteroids. Case Report.

As SARS-CoV-2 and its related clinical syndrome (COVID-19) became a pandemic worldwide, questions regarding its clinical presentation, infectivity, and immune response have been the subject of investigation. We present a case of a patient previously considered recovered from nosocomially transmitted asymptomatic COVID-19 illness, who presented with new respiratory, radiological, and RT-PCR findings consistent with COVID-19, while on high-dose prednisolone due to a suspected secondary demyelinating disease. Importantly, it led to three subsequent cases within patient's household after discharge from the hospital. After reviewing this case in light of current evidence and debates surrounding SARS-CoV-2 RT-PCR results, we hypothesize that patients on corticosteroids may have particular viral shedding dynamics and should prompt a more conservative approach in regard to isolation discontinuation and monitoring.

Duodenal tumors on cross-sectional imaging with emphasis on multidetector computed tomography: a pictorial review.

Duodenal tumours are uncommon, but they can cause significant morbidity and mortality. As stomach and colon are a more common site of gastrointestinal malignancies, radiologists sometimes neglect the duodenum. Multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) can accurately locate and characterize mass-forming duodenal lesions, making them invaluable for the differential diagnosis and determining management strategies such as biopsy or surgery. Although conventional endoscopy continues to play an important role in the diagnosis of duodenal tumors, MDCT and MRI are very useful for evaluating the duodenal wall, extraduodenal space, and surrounding viscera, as well as the intraluminal content seen on endoscopy. This pictorial review aims to illustrate the most common benign and malignant mass-forming duodenal lesions and to focus on the imaging features that are most helpful in reaching the correct diagnosis.

Time window to constrain the corner value of the global seismic-moment distribution.

It is well accepted that, at the global scale, the Gutenberg-Richter (GR) law describing the distribution of earthquake magnitude or seismic moment has to be modified at the tail to properly account for the most extreme events. It is debated, though, how much additional time of earthquake recording will be necessary to properly constrain this tail. Using the global CMT catalog, we study how three modifications of the GR law that incorporate a corner-value parameter are compatible with the size of the largest observed earthquake in a given time window. Current data lead to a rather large range of parameter values (e.g., corner magnitude from 8.6 to 10.2 for the so-called tapered GR distribution). Updating this estimation in the future will strongly depend on the maximum magnitude observed, but, under reasonable assumptions, the range will be substantially reduced by the end of this century, contrary to claims in previous literature.