Assessing changes in regional cerebral hemodynamics in adults with a high-density full-head coverage time-resolved near-infrared spectroscopy device.

Significance: Cerebral oximeters have the potential to detect abnormal cerebral blood oxygenation to allow for early intervention. However, current commercial systems have two major limitations: (1) spatial coverage of only the frontal region, assuming that surgery-related hemodynamic effects are global and (2) susceptibility to extracerebral signal contamination inherent to continuous-wave near-infrared spectroscopy (NIRS). Aim: This work aimed to assess the feasibility of a high-density, time-resolved (tr) NIRS device (Kernel Flow) to monitor regional oxygenation changes across the cerebral cortex during surgery. Approach: The Flow system was assessed using two protocols. First, digital carotid compression was applied to healthy volunteers to cause a rapid oxygenation decrease across the ipsilateral hemisphere without affecting the contralateral side. Next, the system was used on patients undergoing shoulder surgery to provide continuous monitoring of cerebral oxygenation. In both protocols, the improved depth sensitivity of trNIRS was investigated by applying moment analysis. A dynamic wavelet filtering approach was also developed to remove observed temperature-induced signal drifts. Results: In the first protocol (28±5 years; five females, five males), hair significantly impacted regional sensitivity; however, the enhanced depth sensitivity of trNIRS was able to separate brain and scalp responses in the frontal region. Regional sensitivity was improved in the clinical study given the age-related reduction in hair density of the patients (65±15 years; 14 females, 13 males). In five patients who received phenylephrine to treat hypotension, different scalp and brain oxygenation responses were apparent, although no regional differences were observed. Conclusions: The Kernel Flow has promise as an intraoperative neuromonitoring device. Although regional sensitivity was affected by hair color and density, enhanced depth sensitivity of trNIRS was able to resolve differences in scalp and brain oxygenation responses in both protocols.

Epidemic change-point detection in general integer-valued time series.

In this paper, we consider the structural change in a class of discrete valued time series, where the true conditional distribution of the observations is assumed to be unknown. The conditional mean of the process depends on a parameter θ∗ which may change over time. We provide sufficient conditions for the consistency and the asymptotic normality of the Poisson quasi-maximum likelihood estimator (QMLE) of the model. We consider an epidemic change-point detection and propose a test statistic based on the QMLE of the parameter. Under the null hypothesis of a constant parameter (no change), the test statistic converges to a distribution obtained from increments of a Browninan bridge. The test statistic diverges to infinity under the epidemic alternative, which establishes that the proposed procedure is consistent in power. The effectiveness of the proposed procedure is illustrated by simulated and real data examples.

Detection of Hepatitis E Virus (HEV) in Pork Sold in Saint-Louis, the North of Senegal.

The hepatitis E virus (HEV) is a zoonotic pathogen with various hosts, including pigs, which act as reservoirs. In industrialized countries, sporadic cases caused by genotype 3, contracted by ingesting contaminated uncooked or undercooked meat, have been reported. However, in developing countries, HEV infection is mainly dominated by genotype 2 and often associated with poor hygiene conditions and drinking water supplies. HEV infection and its circulation in domestic fauna in West Africa are poorly documented. This study aimed to assess the presence of HEV in pork sold in Saint-Louis, Senegal. Meat products (250 g samples, n = 74) were purchased in August 2022 from three locations. Then, 2 g/sample was minced to extract total nucleic acids using the Purelink™ Viral DNA/RNA kit. RT-PCR reactions were performed using the One-Taq™ One-Step RT-PCR kit targeting the HEV ORF2 genomic region. The products obtained were visualized on a 1% agarose gel. Of a total of 74 samples, divided into pork meat (n = 65) and pork liver (n = 9), 5.4% (n = 4) tested positive for HEV. In both cases, two samples were positive, representing a rate of 3.1% and 22.2% for meat and pork liver, respectively. All new viral sequences were obtained from a monophyletic group within HEV genotype 3. This study is the first to report the presence of HEV in pork sold in Senegal and the results reveal a potential circulation of HEV in the pig population. The high proportion of contamination in the pork liver samples highlights a major risk associated with their consumption.

Field experience with the 8-HPV-type oncoprotein test for cervical cancer screening among HPV-positive women living with and without HIV in LMICs.

Overexpression of HPV-oncoproteins E6 and E7 is necessary for HPV-driven cervical carcinogenesis. Hence, these oncoproteins are promising disease-specific biomarkers. We assessed the technical and operational characteristics of the 8-HPV-type OncoE6/E7 Cervical Test in different laboratories using cervical samples from HPV-positive women living with (WLWH) and without HIV. The 8-HPV-type OncoE6/E7 Test (for short: "OncoE6/E7 test") was performed in 2833 HIV-negative women and 241 WLWH attending multicentric studies in Latin America (ESTAMPA study), and in Africa (CESTA study). Oncoprotein positivity were evaluated at each testing site, according to HIV status as well as type-specific agreement with HPV-DNA results. A feedback questionnaire was given to the operators performing the oncoprotein test to evaluate their impression and acceptability regarding the test. The OncoE6/E7 test revealed a high positivity rate heterogeneity across all testing sites (I2: 95.8%, p < .01) with significant lower positivity in WLWH compared to HIV-negative women (12% vs 25%, p < .01). A similar HPV-type distribution was found between HPV DNA genotyping and oncoprotein testing except for HPV31 and 33 (moderate agreement, k = 0.57). Twenty-one laboratory technicians were trained on oncoprotein testing. Despite operators' concerns about the time-consuming procedure and perceived need for moderate laboratory experience, they reported the OncoE6/E7 test as easy to perform and user-friendly for deployment in resource-limited settings. The high positivity rate variability found across studies and subjectivity in test outcome interpretation could potentially results in oncoprotein false positive/negative, and thus the need for further refinements before implementation of the oncoprotein testing in screen-triage-and-treat approaches is warranted.

Advancing environmental monitoring across the water continuum combining biomarker analysis in multiple sentinel species: A case study in the Seine-Normandie Basin (France).

Nowadays, biomarkers are recognized as valuable tools to complement chemical and ecological assessments in biomonitoring programs. They provide insights into the effects of contaminant exposures on individuals and establish connections between environmental pressure and biological response at higher levels. In the last decade, strong improvements in the design of experimental protocols and the result interpretation facilitated the use of biomarker across wide geographical areas, including aquatic continua. Notably, the statistical establishment of reference values and thresholds enabled the discrimination of contamination effects in environmental conditions, allowed interspecies comparisons, and eliminated the need of a reference site. The aim of this work was to study freshwater-estuarine-coastal water continua by applying biomarker measurements in multi-species caged organisms. During two campaigns, eight sentinel species, encompassing fish, mollusks, and crustaceans, were deployed to cover 25 sites from rivers to the sea. As much as possible, a common methodology was employed for biomarker measurements (DNA damage and phagocytosis efficiency) and data interpretation based on guidelines established using reference values and induction/inhibition thresholds (establishment of three effect levels). The methodology was successfully implemented and allowed us to assess the environmental quality. Employing multiple species per site enhances confidence in observed trends. The results highlight the feasibility of integrating biomarker-based environmental monitoring programs across a continuum scale. Biomarker results align with Water Framework Directive indicators in cases of poor site quality. Additionally, when discrepancies arise between chemical and ecological statuses, biomarker findings offer a comprehensive perspective to elucidate the disparities. Presented as a pilot project, this work contributes to gain insights into current biomonitoring needs, providing new questions and perspectives.

An elevated level of interleukin-17A in a Senegalese malaria cohort is associated with rs8193038 IL-17A genetic variant.

Malaria infection is a multifactorial disease partly modulated by host immuno-genetic factors. Recent evidence has demonstrated the importance of Interleukin-17 family proinflammatory cytokines and their genetic variants in host immunity. However, limited knowledge exists about their role in parasitic infections such as malaria. We aimed to investigate IL-17A serum levels in patients with severe and uncomplicated malaria and gene polymorphism's influence on the IL-17A serum levels. In this research, 125 severe (SM) and uncomplicated (UM) malaria patients and 48 free malaria controls were enrolled. IL-17A serum levels were measured with ELISA. PCR and DNA sequencing were used to assess host genetic polymorphisms in IL-17A. We performed a multivariate regression to estimate the impact of human IL-17A variants on IL-17A serum levels and malaria outcomes. Elevated serum IL-17A levels accompanied by increased parasitemia were found in SM patients compared to UM and controls (P < 0.0001). Also, the IL-17A levels were lower in SM patients who were deceased than in those who survived. In addition, the minor allele frequencies (MAF) of two IL-17A polymorphisms (rs3819024 and rs3748067) were more prevalent in SM patients than UM patients, indicating an essential role in SM. Interestingly, the heterozygous rs8193038 AG genotype was significantly associated with higher levels of IL-17A than the homozygous wild type (AA). According to our results, it can be concluded that the IL-17A gene rs8193038 polymorphism significantly affects IL-17A gene expression. Our results fill a gap in the implication of IL-17A gene polymorphisms on the cytokine level in a malaria cohort. IL-17A gene polymorphisms also may influence cytokine production in response to Plasmodium infections and may contribute to the hyperinflammatory responses during severe malaria outcomes.

Relevance of flounder caging and proteomics to explore the impact of a major industrial accident caused by fire on the Seine estuarine water quality.

On September 26th 2019, a major fire occurred in the Lubrizol factory located near the Seine estuary, in Rouen-France. Juvenile flounders were captured in the Canche estuary (a reference system) and caged one month in the Canche and in the Seine downstream the accident site. No significant increases of PAHs, PCBs and PFAS was detected in Seine vs Canche sediments after the accident, but a significant increase of dioxins and furans was observed in water and sewage sludge in the Rouen wastewater treatment plant. The proteomics approach highlighted a dysregulation of proteins associated with cholesterol synthesis and lipid metabolism, in fish caged in the Seine. The overall results suggested that the fire produced air borne dioxins and furans that got deposited on soil and subsequently entered in the Seine estuarine waters via runoff; thus contaminating fish preys and caged flounders in the Seine estuary.

HPV vaccination in Africa in the COVID-19 era: a cross-sectional survey of healthcare providers' knowledge, training, and recommendation practices.

Introduction: Although the burden of cervical cancer in Africa is highest, HPV vaccination coverage remains alarmingly low in this region. Providers' knowledge and recommendation are key drivers of HPV vaccination uptake. Yet, evidence about providers' knowledge and recommendation practices about the HPV vaccine against a backdrop of emerging vaccine hesitancy fueled by the COVID-19 pandemic is lacking in Africa. Methods: A cross-sectional study was conducted in 2021-2022 among healthcare providers involved in cervical cancer prevention activities in Africa. They were invited to report prior training, the availability of the HPV vaccine in their practice, whether they recommended the HPV vaccine, and, if not, the reasons for not recommending it. Their knowledge about the HPV vaccine was assessed through self-reporting (perceived knowledge) and with three pre-tested knowledge questions (measured knowledge). Results: Of the 153 providers from 23 African countries who responded to the survey (mean age: 38.5 years, SD: 10.1), 75 (54.0%) were female and 97 (63.4%) were based In countries with national HPV immunization programs. Overall, 57 (43.8%) reported having received prior training on HPV vaccine education/counseling, and 40 (37.4%) indicated that the HPV vaccine was available at the facility where they work. Most respondents (109, 83.2%) reported recommending the HPV vaccine in their practice. Vaccine unavailability (57.1%), lack of effective communication tools and informational material (28.6%), and need for adequate training (28.6%) were the most commonly reported reasons for not recommending the HPV vaccine. While 63 providers (52.9%) reported that their knowledge about HPV vaccination was adequate for their practice, only 9.9% responded correctly to the 3 knowledge questions. Conclusion: To increase HPV vaccination coverage and counter misinformation about this vaccine in Africa, adequate training of providers and culturally appropriate educational materials are needed to improve their knowledge of the HPV vaccine and to facilitate effective communication with their patients and the community.

HyperTRCSS: A hyperspectral time-resolved compressive sensing spectrometer for depth-sensitive monitoring of cytochrome-c-oxidase and blood oxygenation.

Significance: Hyperspectral time-resolved (TR) near-infrared spectroscopy offers the potential to monitor cytochrome-c-oxidase (oxCCO) and blood oxygenation in the adult brain with minimal scalp/skull contamination. We introduce a hyperspectral TR spectrometer that uses compressive sensing to minimize acquisition time without compromising spectral range or resolution and demonstrate oxCCO and blood oxygenation monitoring in deep tissue. Aim: Develop a hyperspectral TR compressive sensing spectrometer and use it to monitor oxCCO and blood oxygenation in deep tissue. Approach: Homogeneous tissue-mimicking phantom experiments were conducted to confirm the spectrometer's sensitivity to oxCCO and blood oxygenation. Two-layer phantoms were used to evaluate the spectrometer's sensitivity to oxCCO and blood oxygenation in the bottom layer through a 10 mm thick static top layer. Results: The spectrometer was sensitive to oxCCO and blood oxygenation changes in the bottom layer of the two-layer phantoms, as confirmed by concomitant measurements acquired directly from the bottom layer. Measures of oxCCO and blood oxygenation by the spectrometer were highly correlated with "gold standard" measures in the homogeneous and two-layer phantom experiments. Conclusions: The results show that the hyperspectral TR compressive sensing spectrometer is sensitive to changes in oxCCO and blood oxygenation in deep tissue through a thick static top layer.

Climate and COVID-19 transmission: a cross-sectional study in Africa.

The role of climate in the Coronavirus disease 2019 (COVID-19) transmission appears to be controversial, as reported in earlier studies. In Africa, the subject is poorly documented. In this study, over the period from January 1st, 2020 to September 31, 2022, the daily variations in cumulative confirmed cases of COVID-19 for each African country (54 countries) are modelled through time-series-based approaches and using meteorological factors as covariates. It is suggested from the findings that climate plays a role in COVID-19 transmission since at least one meteorological factor is found to be significant in 32 countries. In decreasing order, the most often occurring meteorological factors are dewpoint temperature, relative and absolute humidity, average temperature and solar radiation. Most of these factors show a lagged effect with confirmed cases (between 0 and 28 days). Also, some meteorological factors exhibit contrasting effects on COVID-19 transmission, resulting in both positive and negative association with cumulative cases, therefore highlighting the complex nature of the interplay between climate and COVID-19 transmission.

Genetic differentiation and structuration of the Gobra zebu cattle breeds reared in Senegal.

The Gobra zebu genetic breeding program has resulted in the genetic improvement of a new population. This population gained genetic characteristics that set them apart from the other cattle populations reared in Senegal. The cause of these differences might be the reproductive isolation and selection to which this population of the "Centre de Recherches Zootechniques" of Dahra has been subjected since the 1950s. This study aimed to assess the genetic differentiation and structuration of this population compared to the main cattle breeds used in Senegal. A total of 180 individuals, selected from the Gobra selection nucleus and bovine populations from four main breeds in Senegal, were included in this study. We used a panel of 21 microsatellite markers among those recommended by the Food Agriculture Organization, to conduct the molecular genotyping of our sampled populations. The basic genetic parameters of differentiation and structuration were calculated using various bioinformatics software. The results of this study, particularly the degrees of genetic differentiation (Fst), the coefficient of genetic homogeneity (Gst), and the gene flow (Nm), show a significant genetic differentiation of the Gobra from the station compared to the other populations studied. Structuring and phylogeny analyses reveal a micro-structuring within the Gobra population as a novelty. This micro-structuring clearly identifies the Gobra individuals from Dahra's station among the other Gobra populations studied. The main causes of these observations would be reproductive isolation and the selection pressure exerted on this population for several decades.

Real-World Effectiveness of Nirmatrelvir/Ritonavir on Coronavirus Disease 2019-Associated Hospitalization Prevention: A Population-based Cohort Study in the Province of Quebec, Canada.

BACKGROUND: Nirmatrelvir/ritonavir has shown to reduce COVID-19 hospitalization and death before Omicron, but updated real-world evidence studies are needed. This study aimed to assess whether nirmatrelvir/ritonavir reduces the risk of COVID-19-associated hospitalization among high-risk outpatients. METHODS: A retrospective cohort study of outpatients with SARS-CoV-2 between March 15 and 15 October 2022, using data from the Quebec clinico-administrative databases. Outpatients treated with nirmatrelvir/ritonavir were compared with infected ones not receiving nirmatrelvir/ritonavir using propensity-score matching. Relative risk (RR) of COVID-19-associated hospitalization within 30 days was assessed using a Poisson regression. RESULTS: A total of 8402 treated outpatients were matched to controls. Regardless of vaccination status, nirmatrelvir/ritonavir treatment was associated with a 69% reduced RR of hospitalization (RR: .31; 95% CI: .28; .36; number needed to treat [NNT] = 13). The effect was more pronounced in outpatients with incomplete primary vaccination (RR: .04; 95% CI: .03; .06; NNT = 8), while no benefit was found in those with a complete primary vaccination (RR: .93; 95% CI: .78; 1.08). Subgroups analysis among high-risk outpatients with a complete primary vaccination showed that nirmatrelvir/ritonavir treatment was associated with a significant decrease in the RR of hospitalization in severely immunocompromised outpatients (RR: .66; 95% CI: .50; .89; NNT = 16) and in high-risk outpatients aged ≥70 years (RR: .50; 95% CI: .34; .74; NNT = 10) when the last dose of the vaccine was received at least 6 months ago. CONCLUSIONS: Nirmatrelvir/ritonavir reduces the risk of COVID-19-associated hospitalization among incompletely vaccinated high-risk outpatients and among some subgroups of completely vaccinated high-risk outpatients.

Fast estimation of adult cerebral blood content and oxygenation with hyperspectral time-resolved near-infrared spectroscopy.

Near-infrared spectroscopy (NIRS) can measure tissue blood content and oxygenation; however, its use for adult neuromonitoring is challenging due to significant contamination from their thick extracerebral layers (ECL; primarily scalp and skull). This report presents a fast method for accurate estimation of adult cerebral blood content and oxygenation from hyperspectral time resolved NIRS (trNIRS) data. A two-phase fitting method, based on a two-layer head model (ECL and brain), was developed. Phase 1 uses spectral constraints to accurately estimate the baseline blood content and oxygenation in both layers, which are then used by Phase 2 to correct for the ECL contamination of the late-arriving photons. The method was validated with in silico data from Monte-Carlo simulations of hyperspectral trNIRS in a realistic model of the adult head obtained from a high-resolution MRI. Phase 1 recovered cerebral blood oxygenation and total hemoglobin with an accuracy of 2.7 ± 2.5 and 2.8 ± 1.8%, respectively, with unknown ECL thickness, and 1.5 ± 1.4 and 1.7 ± 1.1% when the ECL thickness was known. Phase 2 recovered these parameters with an accuracy of 1.5 ± 1.5 and 3.1 ± 0.9%, respectively. Future work will include further validation in tissue-mimicking phantoms with various top layer thicknesses and in a pig model of the adult head before human applications.

Human papillomavirus testing using existing nucleic acid testing platforms to screen women for cervical cancer: implementation studies from five sub-Saharan African countries.

OBJECTIVES: To demonstrate acceptability and operational feasibility of introducing human papillomavirus (HPV) testing as a principal cervical cancer screening method in public health programmes in sub-Saharan Africa. SETTING: 45 primary and secondary health clinics in Malawi, Nigeria, Senegal, Uganda and Zimbabwe. PARTICIPANTS: 15 766 women aged 25-54 years presenting at outpatient departments (Senegal only, general population) or at antiretroviral therapy clinics (all other countries, HIV-positive women only). Eligibility criteria followed national guidelines for cervical cancer screening. INTERVENTIONS: HPV testing was offered to eligible women as a primary screening for cervical cancer, and HPV-positive women were referred for visual inspection with acetic acid (VIA), and if lesions identified, received treatment or referral. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcomes were the proportion of HPV-positive women who received results and linked to VIA and the proportion of HPV-positive and VIA-positive women who received treatment. RESULTS: A total of 15 766 women were screened and tested for HPV, among whom 14 564 (92%) had valid results and 4710/14 564 (32%) were HPV positive. 13 837 (95%) of valid results were returned to the clinic and 3376 (72%) of HPV-positive women received results. Of women receiving VIA (n=2735), 715 (26%) were VIA-positive and 622 (87%) received treatment, 75% on the same day as VIA. CONCLUSIONS: HPV testing was found to be feasible across the five study countries in a public health setting, although attrition was seen at several key points in the cascade of care, namely results return to women and linkage to VIA. Once women received VIA, if eligible, the availability of on-site cryotherapy and thermal ablation allowed for same-day treatment. With sufficient resources and supportive infrastructure to ensure linkage to treatment, use of HPV testing for cervical cancer screening as recommended by WHO is a promising model in low-income and middle-income countries.

A framework for advancing sustainable magnetic resonance imaging access in Africa.

Magnetic resonance imaging (MRI) technology has profoundly transformed current healthcare systems globally, owing to advances in hardware and software research innovations. Despite these advances, MRI remains largely inaccessible to clinicians, patients, and researchers in low-resource areas, such as Africa. The rapidly growing burden of noncommunicable diseases in Africa underscores the importance of improving access to MRI equipment as well as training and research opportunities on the continent. The Consortium for Advancement of MRI Education and Research in Africa (CAMERA) is a network of African biomedical imaging experts and global partners, implementing novel strategies to advance MRI access and research in Africa. Upon its inception in 2019, CAMERA sets out to identify challenges to MRI usage and provide a framework for addressing MRI needs in the region. To this end, CAMERA conducted a needs assessment survey (NAS) and a series of symposia at international MRI society meetings over a 2-year period. The 68-question NAS was distributed to MRI users in Africa and was completed by 157 clinicians and scientists from across Sub-Saharan Africa (SSA). On average, the number of MRI scanners per million people remained at less than one, of which 39% were obsolete low-field systems but still in use to meet daily clinical needs. The feasibility of coupling stable energy supplies from various sources has contributed to the growing number of higher-field (1.5 T) MRI scanners in the region. However, these systems are underutilized, with only 8% of facilities reporting clinical scans of 15 or more patients per day, per scanner. The most frequently reported MRI scans were neurological and musculoskeletal. The CAMERA NAS combined with the World Health Organization and International Atomic Energy Agency data provides the most up-to-date data on MRI density in Africa and offers a unique insight into Africa's MRI needs. Reported gaps in training, maintenance, and research capacity indicate ongoing challenges in providing sustainable high-value MRI access in SSA. Findings from the NAS and focused discussions at international MRI society meetings provided the basis for the framework presented here for advancing MRI capacity in SSA. While these findings pertain to SSA, the framework provides a model for advancing imaging needs in other low-resource settings.

Re-Emergence of Dengue Serotype 3 in the Context of a Large Religious Gathering Event in Touba, Senegal.

Dengue virus (DENV) was detected in Senegal in 1979 for the first time. Since 2017, unprecedented frequent outbreaks of DENV were noticed yearly. In this context, epidemiological and molecular evolution data are paramount to decipher the virus diffusion route. In the current study, we focused on a dengue outbreak which occurred in Senegal in 2018 in the context of a large religious gathering with 263 confirmed DENV cases out of 832 collected samples, including 25 life-threatening cases and 2 deaths. It was characterized by a co-circulation of dengue serotypes 1 and 3. Phylogenetic analysis based on the E gene revealed that the main detected serotype in Touba was DENV-3 and belonged to Genotype III. Bayesian phylogeographic analysis was performed and suggested one viral introduction around 2017.07 (95% HPD = 2016.61-2017.57) followed by cryptic circulation before the identification of the first case on 1 October 2018. DENV-3 strains are phylogenetically related, with strong phylogenetic links between strains retrieved from Burkina Faso and other West African countries. These phylogenetic data substantiate epidemiological data of the origin of DENV-3 and its spread between African countries and subsequent diffusion after religious mass events. The study also highlighted the usefulness of a mobile laboratory during the outbreak response, allowing rapid diagnosis and resulting in improved patient management.

Bioaccumulation of trace metal elements and biomarker responses in caged juvenile flounder at a polluted site: Effects of fish density and time exposure.

This study investigates the effect of fish density and exposure duration on trace metal elements (TME) bioaccumulation and several biomarkers response. Juvenile flounders were caged at low, medium and high densities and exposed during 15 or 30 days in the Seine estuary. The concentrations of the TME measured in the muscle of the caged fish were all in agreement with their bioavailability percentage in the sediments. Higher concentrations of TME were found in flounders' muscle exposed for 15 days compared with those caged for 30 days. For the same exposure time, the density of fish had no effect on the accumulation of the TME in the flounders' muscle. Biomarkers responses varied according to density and duration of exposure. Special care should be taken in their interpretation. We underline that for an optimal assessment of TME pollution in the field, 15 days with low densities of fish per cage are sufficient.

Assessing the Sensitivity of Multi-Distance Hyperspectral NIRS to Changes in the Oxidation State of Cytochrome C Oxidase in the Brain.

Near-infrared spectroscopy (NIRS) measurements of tissue oxygen saturation (StO2) are frequently used during vascular and cardiac surgeries as a non-invasive means of assessing brain health; however, signal contamination from extracerebral tissues remains a concern. As an alternative, hyperspectral (hs)NIRS can be used to measure changes in the oxidation state of cytochrome c oxidase (ΔoxCCO), which provides greater sensitivity to the brain given its higher mitochondrial concentration versus the scalp. The purpose of this study was to evaluate the depth sensitivity of the oxCCO signal to changes occurring in the brain and extracerebral tissue components. The oxCCO assessment was conducted using multi-distance hsNIRS (source-detector separations = 1 and 3 cm), and metabolic changes were compared to changes in StO2. Ten participants were monitored using an in-house system combining hsNIRS and diffuse correlation spectroscopy (DCS). Data were acquired during carotid compression (CC) to reduce blood flow and hypercapnia to increase flow. Reducing blood flow by CC resulted in a significant decrease in oxCCO measured at rSD = 3 cm but not at 1 cm. In contrast, significant changes in StO2 were found at both distances. Hypercapnia caused significant increases in StO2 and oxCCO at rSD = 3 cm, but not at 1 cm. Extracerebral contamination resulted in elevated StO2 but not oxCCO after hypercapnia, which was significantly reduced by applying regression analysis. This study demonstrated that oxCCO was less sensitive to extracerebral signals than StO2.

First wave COVID-19 pandemic in Senegal: Epidemiological and clinical characteristics.

BACKGROUND: The novel coronavirus disease 2019 (COVID-19) pandemic has spread from China to the rest of the world. Africa seems less impacted with lower number of cases and deaths than other continents. Senegal recorded its first case on March 2, 2020. We present here data collected from March 2 to October 31, 2020 in Senegal. METHODS: Socio-demographic, epidemiological, clinical and virological information were collected on suspected cases. To determine factors associated with diagnosed infection, symptomatic disease and death, multivariable binary logistic regression and log binomial models were used. Epidemiological parameters such as the reproduction number and growth rate were estimated. RESULTS: 67,608 suspected cases were tested by the IPD laboratories (13,031 positive and 54,577 negative). All age categories were associated with SARS-CoV-2 infection, but also patients having diabetes or hypertension or other cardiovascular diseases. With diagnosed infection, patients over 65 years and those with hypertension and cardiovascular disease and diabetes were highly associated with death. Patients with co-morbidities were associated with symptomatic disease, but only the under 15 years were not associated with. Among infected, 27.67% were asymptomatic (40.9% when contacts were systematically tested; 12.11% when only symptomatic or high-risk contacts were tested). Less than 15 years-old were mostly asymptomatic (63.2%). Dakar accounted for 81.4% of confirmed cases. The estimated mean serial interval was 5.57 (± 5.14) days. The average reproduction number was estimated at 1.161 (95%CI: 1.159-1.162), the growth rate was 0.031 (95%CI: 0.028-0.034) per day. CONCLUSIONS: Our findings indicated that factors associated with symptomatic COVID-19 and death are advanced age (over 65 years-old) and comorbidities such as diabetes and hypertension and cardiovascular disease.