Distribution, sources and dispersion of polybrominated diphenyl ethers in the water column of the Strait of Georgia, British Columbia, Canada.

Dissolved and particulate polybrominated diphenyl ether (PBDE) concentrations were measured in the water column of the Strait of Georgia (SoG), Haro Strait, Juan de Fuca Strait, Burrard Inlet, and the Fraser River to assess their sources and dispersion. Total PBDE concentrations in the water column of the southern basin of the SoG are surprisingly high (similar to the load reported for coastal zones heavily impacted by human activities). Moreover, the dissolved fraction (i.e. passing through a 2.2 µm pore size filter) accounts for >95 % of the total load, which is unlike what is more typically found in other coastal zones, where particulate PBDEs generally dominate. Decreasing concentrations away from the southern SoG, eventually reaching typical open ocean values in Juan de Fuca Strait, point to the Vancouver metropolitan area as the main proximal source of PBDEs. About half of the direct PBDE input comes from wastewater treatment plants, with atmospheric deposition and the Fraser river accounting for most of the rest. However, these direct sources alone cannot explain the high dissolved PBDE load observed in the water column of southern SoG. PBDE scavenging rates estimated from concentration gradients and water transit times imply a PBDE flux to the seafloor which largely exceeds the measured burial rates of PBDEs in sediments. To reconcile these observations and explain the dominance of the dissolved fraction in the water column of the southern SoG, we invoke and provide supporting evidence for the release of colloidal PBDE from the resuspension of PBDE-contaminated sediments by bottom currents. If confirmed, this continued PBDE exchange between sediments and the water column would maintain high levels of PBDEs, and possibly other hydrophobic and persistent organic contaminants, in the water column of the southern SoG until the contaminated sediments are buried below the sediment mixed layer.

[Trauma and resilience associated with the COVID-19 pandemic in the cities of Bafoussam and Dschang in Cameroon]. / Traumatisme et résilience associés à la pandémie de la COVID-19 dans les villes de Bafoussam et de Dschang au Cameroun.

INTRODUCTION: The emergence of the Covid-19 pandemic in Cameroon, as in Africa and around the world, was marked by a suddenness and unpredictability that fascinated the imagination. The considerable psychic and social repercussions of the pandemic mobilized a significant anguish of death. The sudden onset of the pandemic was followed by spectacular, high-profile deaths that fascinated the imagination, listing it in the order of traumatic events, provoking reactions of astonishment, flight and avoidance. GOAL: The objective of this study is to determine the symptomatology of post-traumatic stress disorder, as well as the resilience, associated with the Covid-19 pandemic in the Western Region of Cameroon. METHODOLOGY: The research was carried out following the model of general population mental health surveys. The availability of area frames (sampling) made it possible to opt for probabilistic calculations. First and second year master's students in clinical psychology from Dschang University were involved in data collection. They benefited from a two-day seminar on data collection techniques in the general population. The calculated sample size is 384 households. The anticipated response rate, set at 90%, made it possible to increase robustness and to anticipate a total sample of 424 households, spread over 3 districts of Bafoussam and Dschang, according to the choice previously made. The study followed the ethical provisions of the Helsinki Protocol. The data collection tools used are: the Impact of Event Scale-Revised and the Connor-Davidson Resilience Scale. RESULTS: 409 subjects were recruited, representing a completion rate of 106.5%. 70.7% of subjects exhibited symptoms of PTSD. These symptoms are more often mild (40.9%) or moderate (25.6%). Women are more affected (73.7%) by PTSD than men (67.9%). In addition to sex and age, area of residence and marital status, appear to be significantly associated with symptoms of PTSD: subjects under 35 years of age have a significantly higher prevalence rate than those over 35; the rate of PTSD is significantly higher in subjects living in urban areas than in those living in rural areas; single subjects are more affected by PTSD (40.1%) than married subjects (26.7%). The average score recorded on the CD-RISC is 64.3, the standard deviation is 15.3 and the coefficient of variation is 24%. This average falls into the second quartile of the distribution, indicating average resilience. CD-RISC scores are not affected by gender, age, marital status, level of education, or occupational status. These characteristics are therefore not factors of resilience. CONCLUSION: The Covid-19 pandemic has had a psychological impact in Cameroon which has made it a major psychosocial stressor. More than 6 in 10 people have symptoms of PTSD. But this symptomatology is often weak or moderate, testifying to an effective resilience, to balance the traumatic effects of the pandemic.

Cr Isotopes and the Engineered Attenuation of Cr(VI)-Rich Runoff.

The leaching of lateritic soils can result in drainage waters with high concentrations of Cr(VI). Such Cr(VI)-rich waters have developed in streams that drain lateritic soils in Central Sulawesi Island, Indonesia. Chromium in this lateritic drainage system is removed by reduction of Cr(VI) to Cr(III) through two faucets delivering an FeSO4 solution to the drainage waters. Cr stable isotope compositions from both water and sediment samples along the drainage path were used to evaluate the efficacy of this remediation strategy. Overall, dissolved [Cr(VI)] decreased moving downstream, but there was an increase in [Cr(VI)] after the first faucet that was effectively removed at the second faucet. This intermittent increase in [Cr(VI)] was the likely result of oxidative remobilization of sediment Cr(III) through reaction with Mn oxides. Cr isotope distributions reflect near quantitative reduction associated with the FeSO4 faucets but also reveal that Cr isotope fractionation is imparted due to Cr redox cycling, downstream. During this redox cycling, fractionation appeared to accompany oxidation, with the product Cr(VI) becoming enriched in 53Cr relative to the reactant Cr(III) with an apparent fractionation factor of 0.7 ± 0.3‰. This study suggests that while FeSO4 effectively removes Cr(VI) from the drainage, the presence of Mn oxides can confound attenuation and improvements to Cr(VI) remediation should consider means of preventing the back reaction of Cr(III) with Mn oxides.

Pembrolizumab Treatment-Induced Liver Toxicity.

T cells play a critical role in immune responses against neoplasm. This finding contributed to the immunotherapy development, an effective treatment for many cancers nowadays. Programmed cell death protein 1 (PD1) is an inhibitory receptor on T cells which downregulate T-cell function per ligation with its ligands (PDL1 and PDL2). PD1 blockade is used to enhance antitumor immunity. Pembrolizumab is a humanized monoclonal anti-PD1 antibody currently used in the management of melanoma, non-small-cell lung cancer, and Hodgkin lymphoma. Most of the treatment toxicities are immune-related adverse events, but grade 3-4 toxicities occur in up to 5% of patients, mainly dermatologic. We present a case of grade 4 pembrolizumab-induced liver toxicity associated with an excellent treatment response in a Caucasian woman.

[Anxiety and Depression Associated with the Management of COVID-19 Among Healthcare workers in Cameroon]. / Anxiété et dépression associées à la prise en charge de la COVID-19 chez les personnels de santé au Cameroun.

OBJECTIVE: The COVID-19 pandemic has had a significant impact worldwide, at different levels. The literature consulted indicates that healthcare workers, who are the first to respond, are generally the ones who pay the highest price. The present study assesses the extent of anxious and depressive symptoms among these actors responding to COVID-19, in the context of Cameroon. METHOD: The Hospital Anxiety and Depression Scale (HADS) was used to assess anxious and depressive symptoms. Data collection involved the use of a web questionnaire for this purpose through the Google Forms virtual platform. The questionnaire link was sent to professional groups spread throughout Cameroon's ten regions. A total of 331 health professionals were interviewed over the period from April 5 to 19, 2020. RESULT: The results show a high rate of anxiety (41.8%) and depression (42.8%). There is a higher susceptibility to depression in young people (30-39 years). Fear of contamination and fear of death are modulators of depression and anxiety. The anxiety-depression comorbidity in the sample is 14.73%. The prevalence rates of major depressive disorder and adjustment disorder in the sample were 8.2% and 3.3%, respectively. The data presented confirm the trends recorded in the literature regarding the impact of fatal epidemics on the mental health of healthcare workers. DISCUSSION: The results indicate, as is the case with most of the work consulted in the literature, that the Covid 19 pandemic is significantly affecting the mental health of healthcare workers. This underlines the urgency of setting up a specialized aid and/or support system, in the context of the current pandemic, such as that of similar health crises. Such a device does not exist in Cameroon, where the mental health response remains weak. CONCLUSION: These results suggest that the healthcare staff involved in the response to COVID-19 in Cameroon are significantly affected in their mental health. This underlines the need for specialized psychological help for nursing staff.

Psychological distress among health care professionals of the three COVID-19 most affected Regions in Cameroon: Prevalence and associated factors.

OBJECTIVES: The present study aimed to assess the prevalence of symptoms of anxiety and depression among health professionals in the three most affected regions in Cameroon. MATERIALS AND METHODS: The study was a descriptive cross-sectional type. Participants were health care professionals working in the three chosen regions of Cameroon. The non_probability convinient sample technique and that of the snowball were valued via a web questionnaire. The non-exhaustive sample size was 292. The diagnosis of anxiety and depression was made by the HAD (Hospital Anxiety and Depression scale). RESULTS: The prevalence of symptoms of anxiety ranging from mild to severe and those of depression were 42.20% and 43.50% respectively. Anxiety symptoms were associated with the age of the participants (P = 0.006), fear of contamination (P = 0.019), fear of death (P = 0.000), and depressive symptoms associated to the fear of death (P = 0.000).

OBJECTIFS: Les auteurs rapportent que le secteur médical est classé à un plus grand risque de contracter le COVID-19 et de le propager potentiellement à d'autres. Le nombre sans cesse croissant de cas confirmés et suspects, la pression dans les soins, l'épuisement des équipements de protection individuelle et le manque de médicaments spécifiques peuvent contribuer à un vécu anxio-dépressif significatif. La présente étude s'est donnée pour ambition d'évaluer la prévalence des symptômes de l'anxiété et de la dépression chez les professionnels de santé dans les trois Régions les plus concernées au Cameroun. MATÉRIELS ET MÉTHODES: Le choix des trois Régions du Cameroun se justifie non seulement par le fait qu'elles totalisent 95,8 % des cas de coronavirus au pays depuis le début de la pandémie, mais aussi parce qu'elles disposent de plus de la moitié des personnels de santé (56 %). Il s'agit d'une étude transversale, descriptive et analytique. Les participants sont des professionnels de la santé en service dans les Régions du Centre, Littoral et de l'Ouest du Cameroun. La méthode d'échantillonnage non probabiliste de convenance couplée à celle de boule de neige via un web questionnaire a été adoptée. La collecte des données a duré du 5 au 19 avril 2020, intervalle de temps après lequel on n'avait plus eu de répondants. À la fin de cette période, la taille de l'échantillon non exhaustive était de 292 professionnels. Le diagnostic de l'état anxio-dépressive était posé via l'échelle de HAD (Hospital Anxiety and Depression scale). Dans le HAD, chaque réponse cotée évalue de manière semi-quantitative l'intensité du symptôme au cours de la semaine écoulée. Un score total est obtenu ainsi que des scores aux deux sous-échelles : le score maximal est de 42 pour l'échelle globale et de 21 pour chacune des sous-échelles. Le coefficient alpha de Cronbach est de 0,70 pour la dépression et de 0,74 pour l'anxiété. Certains auteurs après plusieurs travaux ont proposé qu'une note inférieure ou égale à 7 indique une absence d'anxiété ou de dépression ; celle comprise entre 8 et 10 suggère une anxiété ou une dépression faible à bénigne ; entre 11 et 14, pour une anxiété ou une dépression modérée ; enfin, une note comprise entre 15 et 21 est révélatrice d'une anxiété sévère. Le logiciel Excel 2013 et Epi Info version 7.2.2.6 ont été utilisés pour les traitements statistiques. Les liens entre les variables ont été considérées significatifs pour une valeur de p < 0,05. RÉSULTATS: Les résultats montrent que le personnel féminin a été relativement plus représentatif (54,50 %) avec un sex-ratio (F/M) de 1,19. La classe médiane [31­35 ans] présente la plus grande fréquence (35,30 %) en termes de tranche d'âge. La catégorie Infirmières et Médecins était en tête des répondants avec les fréquences respectives de 57,50 % et 25,30 %. L'étude montre que les prévalences des symptômes de l'anxiété et de la dépression chez le personnel de la santé étaient respectivement de 42,20 % et 43,50 %. On note aussi dans la présente étude des taux de 27,10 % pour l'anxiété modérée et de 15,10 % pour l'anxiété sévère d'une part et d'autre part de 33,90 % pour la dépression modérée et 9,60 % pour la dépression sévère. On a aussi observé une forte disparité de cette prévalence au sein des différentes catégories professionnelles spécifiques. En ce sens, les taux d'anxiété de 57,90 % et de dépression de 52,60 % ont été notés dans la catégorie d'Aide-Soignant, les inscrivant au premier rang de la détresse psychologique. Dans une perspective générale, la symptomatologie anxieuse des soignants était entre autres associée à l'âge des participants (0,006) à la peur de se contaminer (p = 0,019) et de mourir (p = 0,000). En ce qui concerne la symptomatologie dépressive, la seule relation statistiquement significative était celle l'associant à la peur de mourir (p = 0,000). CONCLUSIONS: L'amélioration des conditions de travail et notamment la fourniture d'équipement de protection, la mise en place des cellules spéciales d'écoute pour le personnel de santé pourraient être proposées.

Hepatitis B infection in the rural area of Dschang, Cameroon: seroprevalence and associated factors.

INTRODUCTION: viral hepatitis B remains a major public health problem around the world, especially in underdeveloped and developing countries. Cameroon shows a grate variability in prevalence of this infection in the country and even within different populations groups. The aim of this study was to determine the prevalence and factors associated with viral hepatitis B infection in the rural area of Dschang. METHODS: we conducted a cross-sectional community-based study, involving 551 participants of both genders recruited by a voluntary sampling technique. The biological diagnosis of HBsAg was done by the Immunochromatographic method (PKL® kit of PARAMEDICAL srl laboratories). Positive cases were confirmed by ELISA method (reagent Kit from DIALAB Laboratories). RESULTS: results show a Viral Hepatitis B prevalence of 5.08% (95% CI: 3.2-6.9). University students were the most infected (11/88) with a positivity rate of 12.50% (95%CI: 5.6-19.4). Only 29/551 participants (5.26%) had received at least one dose of vaccine against the disease and were less infected (3.44%) than the others (5.17%). Age (p=0.000), level of education (p=0.013), occupation (p = 0.002), belief in the traditional healing of hepatitis B (p=0.000) and knowledge about the disease and its contamination roads (p=0.049) were associated with viral hepatitis B. CONCLUSION: there is a need of intensifying awareness, education, routine screening and vaccination of the population, especially in schools and university milieu to better counteract the infection with hepatitis B virus in our local Communities.

Immune Checkpoint Inhibitors Rechallenge Efficacy in Non-Small-Cell Lung Cancer Patients.

BACKGROUND: Immune checkpoint inhibitor (ICPi) rechallenge could represent an attractive option in non-small-cell lung cancer (NSCLC), yet no sufficient data supporting this strategy are available. This retrospective observational multicenter national study explored the efficacy of anti-programmed cell death 1 (PD-1)/programmed death ligand 1 (PD-L1) rechallenge in advanced NSCLC patients, looking for potential clinical features associated with greater outcomes. PATIENTS AND METHODS: We retrospectively collected data from 144 advanced NSCLC patients whose disease was rechallenged with ICPis after ≥ 12 weeks of discontinuation. The progression-free survival (PFS) and overall survival (OS) were calculated from first or second ICPi initiation to disease progression (PFS1 and PFSR, respectively), death, or last follow-up (OS1, OSR), respectively. RESULTS: The median (interquartile range) age was 63 (58-70) years. Most patients were male (67%) and smokers (87%). Most had adenocarcinomas (62%) and/or stage IV disease at diagnosis (66%). The best response at rechallenge was not associated with that under the first ICPi (P = 1.10-1). The median (95% confidence interval) PFS1 and PFSR were 13 (10-16.5) and 4.4 (3-6.5) months, respectively. The median (95% confidence interval) OS1 and OSR were 3.3 (2.9-3.9) and 1.5 (1.0-2.1) years, respectively. Longer PFSR and OSR were found in patients discontinuing first ICPi because of toxicity or clinical decision, those not receiving systemic treatment between the two ICPis, and those with good Eastern Cooperative Oncology Group performance status at rechallenge. Only performance status proved to affect outcomes at multivariate analysis. CONCLUSION: Patients discontinuing first ICPi because of toxicity or clinical decision, those able to maintain a treatment-free period, and those with good performance status may be potential candidates for rechallenge.

Chaos theory applied to the outbreak of Covid-19: an ancillary approach to decision-making in pandemic context

Predicting the course of an epidemic is difficult, predicting the course of a pandemic from an emerging virus even more so. The validity of most predictive models relies on numerous parameters, involving biological and social characteristics often unknown or highly uncertain. Data of the COVID-19 epidemics in China, Japan, South Korea and Italy were used to build up deterministic models without strong hypothesis. These models were then applied to other countries to identify the closest scenarios in order to foresee their coming behaviour. The models enabled to predict situations that were confirmed little by little, proving that these tools can be efficient and useful for decision-making in a quickly evolving operational context.

Changes in Circulation and Particle Scavenging in the Amerasian Basin of the Arctic Ocean over the Last Three Decades Inferred from the Water Column Distribution of Geochemical Tracers.

Since the 1980-1990s, international research efforts have augmented our knowledge of the physical and chemical properties of the Arctic Ocean water masses, and recent studies have documented changes. Understanding the processes responsible for these changes is necessary to be able to forecast the local and global consequences of these property evolutions on climate. The present work investigates the distributions of geochemical tracers of particle fluxes and circulation in the Amerasian Basin and their temporal evolution over the last three decades (from stations visited between 1983 and 2015). Profiles of 230-thorium (230Th) and 231-protactinium (231Pa) concentrations and neodymium isotopes (expressed as εNd) measured in the Amerasian Basin prior to 2000 are compared to a new, post-2000s data set. The comparison shows a large scale decrease in dissolved 230Th and 231Pa concentrations, suggesting intensification of scavenging by particle flux, especially in coastal areas. Higher productivity and sediment resuspension from the shelves appear responsible for the concentration decrease along the margins. In the basin interior, increased lateral exchanges with the boundary circulation also contribute to the decrease in concentration. This study illustrates how dissolved 230Th and 231Pa, with εNd support, can provide unique insights not only into changes in particle flux but also into the evolution of ocean circulation and mixing.

[Culinary arts as reinforcement for paediatric end-of-life suffering]. / L'art culinaire pour accompagner les souffrances pédiatriques en fin de vie.

This article presents a support model of paediatric suffering based on a culinary activity guided by the nurse. It is based on a clinical end-of-life situation for a child in a Cameroon hospital. The caring approach helps to strengthen psycho-emotional links between the child and his/her loved ones, and to ease anxieties around the mother/child dyad.

Carbon dioxide release from the North Pacific abyss during the last deglaciation.

Atmospheric carbon dioxide concentrations were significantly lower during glacial periods than during intervening interglacial periods, but the mechanisms responsible for this difference remain uncertain. Many recent explanations call on greater carbon storage in a poorly ventilated deep ocean during glacial periods, but direct evidence regarding the ventilation and respired carbon content of the glacial deep ocean is sparse and often equivocal. Here we present sedimentary geochemical records from sites spanning the deep subarctic Pacific that--together with previously published results--show that a poorly ventilated water mass containing a high concentration of respired carbon dioxide occupied the North Pacific abyss during the Last Glacial Maximum. Despite an inferred increase in deep Southern Ocean ventilation during the first step of the deglaciation (18,000-15,000 years ago), we find no evidence for improved ventilation in the abyssal subarctic Pacific until a rapid transition approximately 14,600 years ago: this change was accompanied by an acceleration of export production from the surface waters above but only a small increase in atmospheric carbon dioxide concentration. We speculate that these changes were mechanistically linked to a roughly coeval increase in deep water formation in the North Atlantic, which flushed respired carbon dioxide from northern abyssal waters, but also increased the supply of nutrients to the upper ocean, leading to greater carbon dioxide sequestration at mid-depths and stalling the rise of atmospheric carbon dioxide concentrations. Our findings are qualitatively consistent with hypotheses invoking a deglacial flushing of respired carbon dioxide from an isolated, deep ocean reservoir, but suggest that the reservoir may have been released in stages, as vigorous deep water ventilation switched between North Atlantic and Southern Ocean source regions.

Eastern Pacific cooling and Atlantic overturning circulation during the last deglaciation.

Surface ocean conditions in the equatorial Pacific Ocean could hold the clue to whether millennial-scale global climate change during glacial times was initiated through tropical ocean-atmosphere feedbacks or by changes in the Atlantic thermohaline circulation. North Atlantic cold periods during Heinrich events and millennial-scale cold events (stadials) have been linked with climatic changes in the tropical Atlantic Ocean and South America, as well as the Indian and East Asian monsoon systems, but not with tropical Pacific sea surface temperatures. Here we present a high-resolution record of sea surface temperatures in the eastern tropical Pacific derived from alkenone unsaturation measurements. Our data show a temperature drop of approximately 1 degrees C, synchronous (within dating uncertainties) with the shutdown of the Atlantic meridional overturning circulation during Heinrich event 1, and a smaller temperature drop of approximately 0.5 degrees C synchronous with the smaller reduction in the overturning circulation during the Younger Dryas event. Both cold events coincide with maxima in surface ocean productivity as inferred from 230Th-normalized carbon burial fluxes, suggesting increased upwelling at the time. From the concurrence of equatorial Pacific cooling with the two North Atlantic cold periods during deglaciation, we conclude that these millennial-scale climate changes were probably driven by a reorganization of the oceans' thermohaline circulation, although possibly amplified by tropical ocean-atmosphere interaction as suggested before.

Reduced nitrogen fixation in the glacial ocean inferred from changes in marine nitrogen and phosphorus inventories.

To explain the lower atmospheric CO2 concentrations during glacial periods, it has been suggested that the productivity of marine phytoplankton was stimulated by an increased flux of iron-bearing dust to the oceans. One component of this theory is that iron-an essential element/nutrient for nitrogen-fixing organisms-will increase the rate of marine nitrogen fixation, fuelling the growth of other marine phytoplankton and increasing CO2 uptake. Here we present data that questions this hypothesis. From a sediment core off the northwestern continental margin of Mexico, we show that denitrification and phosphorite formation-processes that occur in oxygen-deficient upwelling regions, removing respectively nitrogen and phosphorus from the ocean-declined in glacial periods, thus increasing marine inventories of nitrogen and phosphorus. But increases in phosphorus were smaller and less rapid, leading to increased N/P ratios in the oceans. Acknowledging that phytoplankton require nitrogen and phosphorus in constant proportions, the Redfield ratio, and that N/P ratios greater than the Redfield ratio are likely to suppress nitrogen fixation, we suggest therefore that marine productivity did not increase in glacial periods in response to either increased nutrient inventories or greater iron supply.