Paper-based microfluidic electro-analytical device (PMED) for magneto-assay automation: Towards generic point-of-care diagnostic devices

Rapid diagnostic tests (RDTs) for point-of-care (POC) testing of infectious diseases are popular because they are easy to use. However, RDTs have limitations such as low sensitivity and qualitative responses that rely on subjective visual interpretation. Additionally, RDTs are made using paper-bound reagents, which leads to batch-to-batch variability, limited storage stability and detection of only the analytes they were designed for. This work presents the development of a versatile technology, based on short magneto-assays and inexpensive paper-based microfluidic electro-analytical devices (PMEDs). PMEDs were produced locally using low-cost equipment, they were stable at room temperature, easy to use, and provided quantitative and objective results. The devices served to detect alternatively a variety of magneto-assays, granting quantitation of streptavidin-HRP, biotinylated HRP and Pasmodium falciparum lactate dehydrogenase (Pf-LDH) in less than 25 min, using either commercial or customized screen-printed electrodes and measurement equipment. Furthermore, Pf-LDH detection in diluted lysed whole blood displayed a linear response between 3 and 25 ng mL-1, detection and quantification limits ranging between 1 and 3 ng mL-1 and 6-12 ng mL-1, respectively, and provided results that correlated with those of the reference ELISA. In short, this technology is versatile, simple, and highly cost-effective, making it perfect for POC testing.

Nutrition supplementation plus standard of care versus standard of care alone or standard of care plus unconditional cash transfer in the prevention of chronic malnutrition in Southern Angola: study protocol for the MuCCUA study, a cluster randomized controlled trial

BACKGROUND

Chronic malnutrition is a condition associated with negative impacts on physical and cognitive development. It is multi-causal and can start very early in life, already in utero, thus it is especially challenging to find appropriate interventions to tackle it. The government of Angola is implementing a standard of care program with potential to prevent it, and the provision of cash transfers and the supplementation with small quantity lipid-based nutrients (SQ-LNS) are also promising interventions. We aimed to evaluate the impact of the standard of care program alone and of the standard of care plus a cash transfer intervention in the lineal growth of children less than 2 years old and compare it to the effectiveness of a nutrition supplementation plus standard of care program in Southern Angola.

METHODS/DESIGN

The three-arm parallel cluster randomised controlled trial is set in four communes of Huila and Cunene provinces. Clusters are villages or neighbourhoods with a population around 1075 people. A total of twelve clusters were selected per arm and forty pregnant women are expected to be recruited in each cluster. Pregnant women receive the standard of care alone, or the standard of care plus unconditional cash transfer or plus nutritional supplementation during the first 1000 days, from pregnancy to the child reaching 24 months. The primary outcome is the prevalence of stunting measured as height-for-age Z-score (HAZ) < -2 in children below 2 years. Impact will be assessed at 3, 6, 12, 18 and 24 months of children's age. Secondary outcomes include mortality, morbidity, caring, hygiene and nutrition behaviours and practices, and women and children's dietary diversity. Quantitative data are also collected on women's empowerment, household food security, expenditure and relevant clinical and social events at baseline, endline and intermediate time points.

DISCUSSION

The results will provide valuable information on the impact of the standard of care intervention alone as well as combined with an unconditional cash transfer intervention compared to a nutrition supplementation plus standard of care intervention, carried out during the first 1000 days, in the children´s growth up to 2 years and related outcomes in Southern Angola.

TRIAL REGISTRATION

Clinical Trials NCT05571280. Registered 7 October 2022.

Chagas disease deaths detected among garbage codes registered in mortality statistics in Brazil: a study from the buRden of ChAgas dISEase in the contemporary world (RAISE) project

OBJECTIVES

The objective of this study was to identify Brazil's most critical garbage codes (GCs) reclassified to Chagas disease (ChD) in mortality data and their proportions. We also estimated the potential impact of misclassification on the number of deaths attributed to ChD.

STUDY DESIGN

Population-based descriptive study.

METHODS

We used the Mortality Information System (SIM; in Portuguese) data before and after routine GC investigation in 2015-2019 to evaluate ChD deaths detected among them. We identified priority GCs, which contributed more than 0.1 % to the percentage of total ChD deaths registered. Spearman's correlation was used to evaluate the association between the reclassification of priority GCs and ChD prevalence. Then, we applied the GC correction factors to estimate the number of deaths attributed to ChD.

RESULTS

22,154 deaths were reported as ChD in the study period. Among them, 1004 deaths originally listed as priority GCs were deaths reclassified to ChD after an investigation in the SIM final database. Unspecific cardiomyopathy (10.2 %), unspecific heart diseases (4.7 %), and heart failure (2.8 %) were GCs with the highest proportions of reclassification to ChD in Brazil. Higher ChD prevalence at the state level was associated with a higher proportion of GC deaths reclassified as ChD. When applying correction factors identified after investigation, we estimated an increase of 26.4 % in registered ChD deaths, mostly in states with higher endemicity.

CONCLUSIONS

GCs might conceal deaths due to ChD, particularly in Brazil's states with higher endemicity. The approach suggested in this study may offer an alternative method for estimating ChD-related deaths in endemic countries.

Balloon-Expandable Pulmonary Valves for Patched or Native Right Ventricular Outflow Tracts

The implantation of percutaneous balloon expandable valves in native or patched right ventricular outflow tracts (nRVOT) is a challenging technique due to the diversity of anatomies and shapes, the large sizes, and the distensibility of the nRVOT, for which specific techniques have been developed. We present a single center experience with balloon expandable percutaneous pulmonary valves in nRVOT, describing the techniques used, complications observed, and a short-mid term follow-up.. This is a single center descriptive study of patients who underwent a percutaneous pulmonary valve implantation in a nRVOT with a balloon expandable pulmonary valve in our center between September 2012 and June 2022.. We implanted successfully 45 valves in 46 patients (20 Sapien and 25 Melody). Tetralogy of Fallot or pulmonary atresia with VSD were the main congenital heart disease (n = 32). All were pre-stented, 18 in a one step procedure. We used a Dryseal sheath in 13/21 Sapien. In 6 patients we used the anchoring technique, 5 with a very large nRVOT and one pyramidal nRVOT. In the 3.5 year follow-up 7 patients developed endocarditis and 3 required a valve redilation, no fractures were observed. PPVI of native RVOT with balloon expandable valves is feasible in a number of selected anatomies, including large or pyramidal nRVOT, using specific techniques, (presenting, LPA anchoring).

Percutaneous interventions in Fontan circulation

Background

In light of increased survival of patients with Fontan circulation, percutaneous interventions in these patients have become growingly significant in the recent years. Percutaneous treatments in patients with univentricular physiology can optimize the short term hemodynamics in these patients. However, information on long term outcomes is scarce.

Purpose

To present the cumulative work experience in percutaneous interventions of a tertiary center in the past 12 years in patients that have undergone total cavopulmonary deviation (TCD) and to investigate long term outcomes.

Methods

In this retrospective study, all patients with TCD that underwent follow-up in our specialized department of congenital heart disease in the past 12 years, were eligible for chart-review. Cardiac catheterization was performed by experienced interventional cardiologists, specialized in structural interventions in congenital heart disease. All catheterizations were performed under general anesthesia and mechanical ventilation. All patients underwent Fontan pressure measurements and cardiac output estimation with Fick method.

Results

A total of 80 patients, with a mean follow-up time of 24 (±7.1) years, were included in the study. Details on baseline characteristics are depicted in Table 1. Fifty-two (65%) patients underwent percutaneous intervention during follow-up, and 33% (n=17) of these patients required multiple interventions. Angioplasty with stent implantation of the Fontan conduit or the pulmonary arteries was the most common intervention (30 (58%) and 8 (15%) patients, respectively), followed by embolization of collaterals (11 (21%) patients). Patients with right systemic ventricle physiology needed more interventions and had a shorter time-to-first-intervention period. (Figure 1) Pacemaker implantation was required in a total of 15 patients, being significantly more frequent in patients with atriopulmonary connection than in patients with lateral tunnel or extracardiac conduit (11 (36%) vs 4 (11%), p&lt;0.01). Overall long-term outcome (with regards to mortality) was good (4 (0.5%) patients). Patients that required percutaneous structural interventions showed a tendency towards a higher mortality than those not in need of intervention (4 (8%) vs 0 (0%), respectively, p=0.14).

Conclusions

During long-term follow-up of patients with Fontan circulation, almost two thirds of the patients required percutaneous intervention. Patients with right systemic ventricle physiology were in greater need of intervention. Patients that required intervention had a tendency towards a worse clinical outcome.

Funding Acknowledgement

Type of funding sources: None.

Treatment of ACL injury in a professional soccer player during COVID-19 lockdown

Anterior Cruciate Ligament (ACL) injuries stand out as the most severe in sports such as soccer. This study presents the rehabilitation process of a professional soccer player who suffered a total ACL tear. It details the treatment performed after the surgical intervention and all the adaptations that had to be applied in the rehabilitation process due to the lockdown period established at the beginning of the COVID-19 pandemic. During the period comprised between weeks 9 and 21 post-surgery, the rehabilitation treatment was carried out virtually, adapting the actions, work environment and equipment used. Despite the limitations it entailed, the virtual format and the adaptations in the treatment allowed the rehabilitation process to continue, fulfilling all the pre-established objectives and deadlines with a consequent satisfactory and safe return to competitive sport. After carrying out a bibliographic research, no clinical cases have been found regarding the adaptation of the rehabilitation process of an ACL reconstruction in a professional soccer player during the COVID-19 lockdown.

Search for Subsolar-Mass Binaries in the First Half of Advanced LIGO's and Advanced Virgo's Third Observing Run

We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2  M_{⊙} and 1.0  M_{⊙} in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend our previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q≥0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14  yr^{-1}. This implies an upper limit on the merger rate of subsolar binaries in the range [220-24200]  Gpc^{-3} yr^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes in the mass range 0.2  M_{⊙}<m_{PBH}<1.0  M_{⊙} is f_{PBH}≡Ω_{PBH}/Ω_{DM}≲6%. This improves existing constraints on primordial black hole abundance by a factor of ∼3. The other is a dissipative dark matter model, in which fermionic dark matter can collapse and form black holes. The upper limit on the fraction of dark matter black holes depends on the minimum mass of the black holes that can be formed: the most constraining result is obtained at M_{min}=1  M_{⊙}, where f_{DBH}≡Ω_{DBH}/Ω_{DM}≲0.003%. These are the first constraints placed on dissipative dark models by subsolar-mass analyses.

Association of HLA-B*35 and moderate or severe cutaneous reactions secondary to benznidazole treatment in chronic Chagas disease patients

OBJECTIVES

Benznidazole is the first line treatment for Chagas disease. Adverse events appear in more than 50% of patients, leading to discontinuation in approximately 15%. Cutaneous reactions are one of the most frequent adverse events. HLA-genotyping previous studies identified an association between cutaneous reactions to benznidazole and carrying the specific allele HLA-B*35:05. We designed the present study to prospectively confirm this association.

METHODS

This is a prospective observational study including Chagas disease patients aged 18 years or more who accepted to receive benznidazole treatment following current guidelines. Allele genotyping of HLA-B was determined in all patients. Clinical and analytical follow-up was performed at days 0, 7, 14, 30 and 60 of treatment.

RESULTS

Two-hundred and seven patients were included. Seventy percent were female with a mean age of 45.1 (SD ±9.86) years mainly from Bolivia (92.8%). In 102 (49.3%) cases a cutaneous reaction was diagnosed. Forty-eight (46.6%) were classified as mild, 37 (35.9%) as moderate and 18 (17.5%) as severe. Thirty-two (15.4%) patients had to definitively interrupt the treatment due to a cutaneous reaction. Female sex (OR 4.49; 95%CI 1.62-12.47), new-onset eosinophilia prior to cutaneous symptoms (OR 2.55; 95%CI 1.2-5.43) and carrying the HLA-B*35 allelic group (OR 2.58; 95%CI 1.2-5.51) were all predictors of moderate to severe cutaneous reactions. No statistical significance was found when the specific allele HLA-B*35:05 was analyzed.

CONCLUSIONS

Patients carrying the HLA-B*35 allelic group are at higher risk of moderate to severe reactions when taking benznidazole treatment.

Clinical characteristics and in-hospital outcomes of patients coinfected with Chagas disease and SARS-CoV-2

Background

Underlying comorbidities have been widely associated with a worse prognosis for COVID-19 patients, since viral infections could act as triggers for worsening of chronic diseases.

Although Chagas disease (CD) is endemic in Latin America, it has been recognized that the disease is now a worldwide concern. Information on the interplay between COVID-19 and CDis lacking.

Purpose

To assess clinical characteristics and in-hospital outcomes of patients with CD and COVID-19, and to compare it to non-CD patients.

Methods

Patients with COVID-19 diagnosis were selected from the Brazilian COVID-19 Registry, a prospective multicenter cohort, from March to September, 2020. CD diagnosis was based on hospital record at the time of admission. Study data were collected by trained hospital staff using Research Electronic Data Capture (REDCap) tools. Genetic matching for sex, age, hypertension, DM and hospital was performed in a 4:1 ratio.

Results

Of the 7,018 patients who had confirmed infection with SARS-CoV-2 in the registry, 31 patients with CD and 124 matched controls were included. Overall, the median age was 72 (64.-80) years-old and 44.5% were male. At baseline, heart failure (25.8% vs. 9.7%) and atrial fibrillation (29.0% vs. 5.6%) were more frequent in CD patients than in the controls (p&lt;0.05 for both). C-reactive protein levels were lower in CD patients compared with the controls (55.5 [35.7, 85.0] vs. 94.3 [50.7, 167.5] mg/dL). Seventy-two (46.5%) patients required admission to the intensive care unit. In-hospital management, outcomes and complications were similar between the groups (Table 1).

Conclusions

In this large Brazilian COVID-19 Registry, CD patients had a higher prevalence of atrial fibrillation and chronic heart failure compared with non-CD controls, with no differences in-hospital outcomes. The lower C-reactive protein levels in CD patients require further investigation.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This study was supported in part by Minas Gerais State Agency for Research and Development (Fundação de Amparo à Pesquisa do Estado de Minas Gerais - FAPEMIG) [grant number APQ-00208-20], National Institute of Science and Technology for Health Technology Assessment (Instituto de Avaliação de Tecnologias em Saúde – IATS)/ National Council for Scientific and Technological Development (Conselho Nacional de Desenvolvimento Científico e Tecnolόgico - CNPq) [grant number 465518/2014-1], Table 1. Clinical outcomes

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Impact of the COVID-19 pandemic on tuberculosis management in Spain

Background

The impact of COVID-19 on the diagnosis and management of tuberculosis (TB) patients is unknown.

Methods

Participating centres completed a structured web-based survey regarding changes to TB patient management during the COVID-19 pandemic. The study also included data from participating centres on patients aged ≥18 diagnosed with TB in 2 periods: March 15 to June 30, 2020 and March 15 to June 30, 2019. Clinical variables and information about patient household contacts were retrospectively collected.

Results

A total of 7 (70%) TB units reported changes in their usual TB team operations. Across both periods of study, 169 patients were diagnosed with active TB (90 in 2019, 79 in 2020). Patients diagnosed in 2020 showed more frequent bilateral lesions in chest X-ray than patients diagnosed in 2019 (P = 0.004). There was a higher percentage of latent TB infection and active TB among children in households of patients diagnosed in 2020, compared with 2019 (P = 0.001).

Conclusions

The COVID-19 pandemic has caused substantial changes in TB care. TB patients diagnosed during the COVID-19 pandemic showed more extended pulmonary forms. The increase in latent TB infection and active TB in children of patient households could reflect increased household transmission due to anti-COVID-19 measures.

Acute respiratory distress syndrome due to COVID-19. Clinical and prognostic features from a medical Critical Care Unit in Valencia, Spain

Objective

Information from critically ill coronavirus disease 2019 (COVID-19) patients is limited and in many cases coming from health systems approaches different from the national public systems existing in most countries in Europe. Besides, patient follow-up remains incomplete in many publications. Our aim is to characterize acute respiratory distress syndrome (ARDS) patients admitted to a medical critical care unit (MCCU) in a referral hospital in Spain.

Design

Retrospective case series of consecutive ARDS COVID-19 patients admitted and treated in our MCCU.

Setting

36-bed MCCU in referral tertiary hospital.

Patients and participants

SARS-CoV-2 infection confirmed by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay of nasal/pharyngeal swabs.

Interventions

None.

Main variables of interest

Demographic and clinical data were collected, including data on clinical management, respiratory failure, and patient mortality.

Results

Forty-four ARDS COVID-19 patients were included in the study. Median age was 61.50 (53.25 - 67) years and most of the patients were male (72.7%). Hypertension and dyslipidemia were the most frequent co-morbidities (52.3 and 36.4% respectively). Steroids (1mg/Kg/day) and tocilizumab were administered in almost all patients (95.5%). 77.3% of the patients needed invasive mechanical ventilation for a median of 16 days [11-28]. Prone position ventilation was performed in 33 patients (97%) for a median of 3 sessions [2-5] per patient. Nosocomial infection was diagnosed in 13 patients (29.5%). Tracheostomy was performed in ten patients (29.4%). At study closing all patients had been discharged from the CCU and only two (4.5%) remained in hospital ward. MCCU length of stay was 18 days [10-27]. Mortality at study closing was 20.5% (n 9); 26.5% among ventilated patients.

Conclusions

The seven-week period in which our MCCU was exclusively dedicated to COVID-19 patients has been challenging. Despite the severity of the patients and the high need for invasive mechanical ventilation, mortality was 20.5%.

Efficacy and safety assessment of different dosage of benznidazol for the treatment of Chagas disease in chronic phase in adults (MULTIBENZ study): study protocol for a multicenter randomized Phase II non-inferiority clinical trial

BACKGROUND

Chagas disease (CD) continues to be a neglected infectious disease with one of the largest burdens globally. Despite the modest cure rates in adult chronic patients and its safety profile, benznidazole (BNZ) is still the drug of choice. Its current recommended dose is based on nonrandomized studies, and efficacy and safety of the optimal dose of BNZ have been scarcely analyzed in clinical trials.

METHODS/DESIGN

MULTIBENZ is a phase II, randomized, noninferiority, double-blind, multicenter international clinical trial. A total of 240 patients with Trypanosoma CD in the chronic phase will be recruited in four different countries (Argentina, Brazil, Colombia, and Spain). Patients will be randomized to receive BNZ 150 mg/day for 60 days, 400 mg/day for 15 days, or 300 mg/day for 60 days (comparator arm). The primary outcome is the efficacy of three different BNZ therapeutic schemes in terms of dose and duration. Efficacy will be assessed according to the proportion of patients with sustained parasitic load suppression in peripheral blood measured by polymerase chain reaction. The secondary outcomes are related to pharmacokinetics and drug tolerability. The follow-up will be 12 months from randomization to end of study participation. Recruitment was started in April 2018.

CONCLUSION

This is a clinical trial conducted for the assessment of different dose schemes of BNZ compared with the standard treatment regimen for the treatment of CD in the chronic phase. MULTIBENZ may help to clarify which is the most adequate BNZ regimen in terms of efficacy and safety, predicated on sustained parasitic load suppression in peripheral blood.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03191162. Registered on 19 June 2017.

Molecular detection of Rickettsia infection in field-collected bed bugs

Bed bugs are now one of the most prevalent human-associated, blood-feeding pests in the urban world, but few studies of their association with human pathogens have been conducted since their resurgence. Here, we used PCR to screen samples of field-collected bed bugs (Cimex spp.) for the presence of Rickettsia bacteria and we describe the first detection of an uncharacterized Rickettsia in Cimex lectularius in nature. Rickettsia was detected in 5/39 (12.8%) of the bed bug samples tested. In particular, three pools from the USA and two individual insects from the UK were positive for Rickettsia DNA. Sequencing and analysis of a fragment of the citrate synthase gene (gltA) from positive samples from each country revealed that the Rickettsia detected in both were identical and were closely related to a Rickettsia previously detected in the rat flea Nosopsyllus laeviceps. Additional experiments indicated that the Rickettsia localizes to multiple tissues in the bed bug and reaches high titres. Attempts were made to infect mammalian cells in culture but these efforts were inconclusive. Our findings suggest that Rickettsia are secondary endosymbionts of bed bugs and have potential implications for both bed bug control and public health. However, further investigation is required to determine the pathogenicity of this Rickettsia, its transmission mechanisms, and its contributions to bed bug physiology.

Modeling the two- and three-dimensional displacement field in Lorca, Spain, subsidence and the global implications

Land subsidence associated with overexploitation of aquifers is a hazard that commonly affects large areas worldwide. The Lorca area, located in southeast Spain, has undergone one of the highest subsidence rates in Europe as a direct consequence of long-term aquifer exploitation. Previous studies carried out on the region assumed that the ground deformation retrieved from satellite radar interferometry corresponds only to vertical displacement. Here we report, for the first time, the two- and three-dimensional displacement field over the study area using synthetic aperture radar (SAR) data from Sentinel-1A images and Global Navigation Satellite System (GNSS) observations. By modeling this displacement, we provide new insights on the spatial and temporal evolution of the subsidence processes and on the main governing mechanisms. Additionally, we also demonstrate the importance of knowing both the vertical and horizontal components of the displacement to properly characterize similar hazards. Based on these results, we propose some general guidelines for the sustainable management and monitoring of land subsidence related to anthropogenic activities.

GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral

On August 17, 2017 at 12∶41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0×10^{4}  years. We infer the component masses of the binary to be between 0.86 and 2.26  M_{⊙}, in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17-1.60  M_{⊙}, with the total mass of the system 2.74_{-0.01}^{+0.04}M_{⊙}. The source was localized within a sky region of 28  deg^{2} (90% probability) and had a luminosity distance of 40_{-14}^{+8}  Mpc, the closest and most precisely localized gravitational-wave signal yet. The association with the γ-ray burst GRB 170817A, detected by Fermi-GBM 1.7 s after the coalescence, corroborates the hypothesis of a neutron star merger and provides the first direct evidence of a link between these mergers and short γ-ray bursts. Subsequent identification of transient counterparts across the electromagnetic spectrum in the same location further supports the interpretation of this event as a neutron star merger. This unprecedented joint gravitational and electromagnetic observation provides insight into astrophysics, dense matter, gravitation, and cosmology.

Serodiscordance in chronic Chagas disease diagnosis: a real problem in non-endemic countries

According to the WHO, chronic Chagas disease (CD) diagnosis is based on two serological techniques. To establish a definitive diagnosis, the results must be concordant. In cases of discordances, the WHO proposes repeating serology in a new sample, and if results remain inconclusive, a confirmatory test should be performed. This study, conducted at two Tropical Medicine Units in Europe over 4 years, aims to assess the diagnostic yield of TESA- (trypomastigote excreted-secreted antigens) blot as a confirmatory technique in patients with inconclusive and discordant results. Of 4939 individuals screened, 1124 (22.7%) obtained positive results and 165 (3.3%) discordant results. Serology was repeated in 88/165 sera and discrepancies were solved in 25/88 (28.4%) cases. Patients without a definitive diagnosis were classified in two different groups: Group 1, including patients with inconclusive results despite retesting (n = 63), and Group 2, including patients with discordant results not retested (n = 77). TESA-blot was performed for all of Group 1 and 39/77 of Group 2 and was positive for 33/63 (52.4%) and 21/39 (53.8%), respectively. Analysis of Group 1 results showed a moderate agreement between results of the ELISA based on native antigen and TESA-blot (κ 0.53). In contrast, a clear disagreement was observed between the ELISA based on recombinant antigens and TESA-blot (κ <0). A sizeable proportion of patients are suspected to have CD with inconclusive results or in whom re-testing is not feasible. TESA-blot was positive in half of these patients, highlighting the need for a confirmatory assay in European centres caring for exposed individuals.

Immunosuppression and Chagas disease; experience from a non-endemic country

Reactivation of Chagas disease in the chronic phase may occur when immunosuppression is established, sometimes resulting in high parasitaemia and severe clinical manifestations such as meningitis and meningoencephalitis. Although this situation is being increasingly described, there is still scarce information. This retrospective observational study was performed in three Tropical Medicine Units of Barcelona (Spain) included in the International Health Programme of the Catalan Health Institute (PROSICS). The objective of the study was to describe epidemiological, clinical, microbiological, prognostic and therapeutic data from patients with Chagas disease and any kind of immunosuppressive condition attended in these three institutions from January 2007 to October 2014. From 1823 patients with Chagas disease attending these three centres during the study period, 38 (2%) had some kind of immunosuppressive condition: 12 patients had human immunodeficiency virus infection, 8 patients had neoplasia, 4 patients underwent organ transplantation and 14 patients had an autoimmune disease. Eight (21.1%) patients had cardiac involvement, and six (15.8%) patients had gastrointestinal involvement. Acute Trypanosoma cruzi infection was detected in two Spanish patients. Thirty-one (81.6%) patients received treatment with benznidazole, of whom 17 (54.8%) had some kind of adverse event. No patient had a severe manifestation or reactivation of Chagas disease. Patients with Chagas disease under immunosuppressive conditions are being increasingly described, especially in non-endemic countries. More information about this topic is required and international consensus in the diagnosis, treatment and follow up of these patients must be established to reduce the morbidity and mortality.

[Video-assisted sigmoidectomy as an option for Sigmoid volvulus management in the pediatric population]

INTRODUCTION

The aim of the present study was to evaluate clinical presentation and management of sigmoid volvulus in children. Sigmoid volvulus is one of the three leading causes of acute obstruction of the colon and is between 50 and 90% of all large bowel volvulus. In the pediatric population only 3 to 5% of bowel obstructions are caused by volvulus and there are less than 100 cases reported in the literature. The presence of a redundant sigmoid with a narrow mesentery (dolicosigmoide) is a prerequisite for the volvulus formation. The etiology in the pediatric population is considered secondary to the presence of a broad meso with a narrow base associated with abnormal fixation colon. Other factors include history of anorectal malformation, Prune Belly syndrome, intestinal malrotation and Hirschsprung disease. Initial management followed by endoscopic minimally invasive sigmoidectomy has proven safe and effective.

MATERIALS AND METHODS

This paper presents the experience of 4 patients between 9 and 14 managed in our department in 2013, with a diagnosis of volvulus of the sigmoid, which were initially taken to a first surgical endoscopic decompression of volvulus and a second half were carried sigmoid which took place in a video-assisted. In this series, no intraoperative complications were documented and monitoring more than six months only one patient has required new interventions, in a special case because the patient has associated myopathy; inflammatory leiomioscitis, which predisposes to episodes of intestinal obstruction.

CONCLUSION

We believe that endoscopic detorsion followed by an early video-assisted sigmoid is the ideal technique for the management of these patients.

[Acoustic contamination in urgent medical transportation by road]

BACKGROUND

To determine levels of exposure to noise during urgent medical transportation by road and to describe the perception of hearing function impairment in workers and the use of hearing protection devices.

MATERIAL AND METHODS

An observational study was performed in Bizkaia (Spain). The instantaneous maximum noise levels (L(peak)) and its continuous equivalents (L(eq)) were recorded through sonometric dosimetries, measured in a "sample ambulance" of the emergency network. In parallel, a survey was conducted on a representative sample of 127 workers in which self-reported hearing loss and associated factors were explored, in addition to other issues of concern from the perspective of prevention of occupational hazards.

RESULTS

L(peak) oscillating between 80 and 109 dBA were recorded depending on the location. The average Leq levels measured over 10 emergency calls, from activation until arrival at the incident and during transport to the hospital, were of 79.5 dBA and 74.3 dBA (p <0.001) respectively. Thirty-six point two percent of the surveyed workers spoke of hearing impairment in recent years. The independent variables associated with increased risk were: age over 45 years, professional seniority over 15 years and male gender. The strategies used to mitigate the siren's noise during the emergency were closing the windows of the ambulance and using the dimmer at night.

CONCLUSIONS

The values of the dosimetries do not exceed the critical values provided, but there is a high prevalence of hearing-impaired problems reported by the workers. Emphasis should be placed on the adoption of strategies to reduce noise and its effects on the ambulance service.

Evaluation of a change detection methodology by means of binary thresholding algorithms and informational fusion processes

Landcover is subject to continuous changes on a wide variety of temporal and spatial scales. Those changes produce significant effects in human and natural activities. Maintaining an updated spatial database with the occurred changes allows a better monitoring of the Earth’s resources and management of the environment. Change detection (CD) techniques using images from different sensors, such as satellite imagery, aerial photographs, etc., have proven to be suitable and secure data sources from which updated information can be extracted efficiently, so that changes can also be inventoried and monitored. In this paper, a multisource CD methodology for multiresolution datasets is applied. First, different change indices are processed, then different thresholding algorithms for change/no_change are applied to these indices in order to better estimate the statistical parameters of these categories, finally the indices are integrated into a change detection multisource fusion process, which allows generating a single CD result from several combination of indices. This methodology has been applied to datasets with different spectral and spatial resolution properties. Then, the obtained results are evaluated by means of a quality control analysis, as well as with complementary graphical representations. The suggested methodology has also been proved efficiently for identifying the change detection index with the higher contribution.

Characterizing olive grove canopies by means of ground-based hemispherical photography and spaceborne RADAR data

One of the main strengths of active microwave remote sensing, in relation to frequency, is its capacity to penetrate vegetation canopies and reach the ground surface, so that information can be drawn about the vegetation and hydrological properties of the soil surface. All this information is gathered in the so called backscattering coefficient (σ(0)). The subject of this research have been olive groves canopies, where which types of canopy biophysical variables can be derived by a specific optical sensor and then integrated into microwave scattering models has been investigated. This has been undertaken by means of hemispherical photographs and gap fraction procedures. Then, variables such as effective and true Leaf Area Indices have been estimated. Then, in order to characterize this kind of vegetation canopy, two models based on Radiative Transfer theory have been applied and analyzed. First, a generalized two layer geometry model made up of homogeneous layers of soil and vegetation has been considered. Then, a modified version of the Xu and Steven Water Cloud Model has been assessed integrating the canopy biophysical variables derived by the suggested optical procedure. The backscattering coefficients at various polarized channels have been acquired from RADARSAT 2 (C-band), with 38.5° incidence angle at the scene center. For the soil simulation, the best results have been reached using a Dubois scattering model and the VV polarized channel (r(2) = 0.88). In turn, when effective LAI (LAI(eff)) has been taken into account, the parameters of the scattering canopy model are better estimated (r(2) = 0.89). Additionally, an inversion procedure of the vegetation microwave model with the adjusted parameters has been undertaken, where the biophysical values of the canopy retrieved by this methodology fit properly with field measured values.

[Initial experience in single site laparoscopic surgery in a pediatric hospital of Bogotá]

BACKGROUND

Minimally invasive surgery is the current accepted approach for abdominal surgery. However, less invasive techniques such as single incision laparoscopic surgery (SILS) are being used more frequently and we believe it will become the standard choice for abdominal surgery. This report describes our initial experience with Single Port Incision Surgery (SILS).

METHODS

We reviewed all the patients who underwent SILS in our hospital between November 2009 and July 2011. We used a surgical glove attached to a wound retractor to yield a multi-port hybrid.

RESULTS

We present 80 patients with a mean age of 8.6 years and mean weight of 32,1 kg. The youngest patient was 8 days old and the smallest patient weighed 2.5 kg. The average duration of surgery was 48.2 minutes. The average length of stay was 48.7 hours. Different procedures were performed: appendectomies for early appendicitis (55%), hepatic biopsies (15%), appendectomies for perforated appendicitis (7.5%), and the following isolated cases: cholecystectomy, Meckel's diverticulum resection, oophorectomy, salpingo-oophorectomy, ovarian cystectomy, bowel biopsy, and a resection of an accessory spleen torsion. SILS was successfully completed in 78 cases, and 2 cases were converted to standard laparoscopy and none to open surgery. There were no intraoperative surgical complications. Postoperative complications presented in 5 cases: a superficial incisional site infection, two residual abdominal abscesses, one bowel obstruction and one evisceration. The last two cases subsequently resulted in reoperation and occurred early in our learning curve.

CONCLUSIONS

SILS is a reproducible and viable technique that may be used successfully in pediatric surgery. It may be used safely in different procedures and age groups, even in neonates. Time of surgery decreased with our learning curve. Additionally, excellent cosmetic results were obtained as evidenced by imperceptible umbilical scarring.

Small area estimation under Fay–Herriot models with non-parametric estimation of heteroscedasticity

Fay–Herriot models relate direct estimators of small area means to vectors of area-level auxiliary covariates. Estimation of error variances in these models is a problem because of the lack of data within areas. A non-parametric approach is proposed for estimating these variances. Estimators of the remaining model parameters are derived and their asymptotic properties are studied. Moreover, small area estimators that incorporate the estimated error variances are obtained and several simple estimators of the mean squared error of these estimators are proposed. Simulation experiments study the small sample performance of the new small area estimators and compare the different estimators of the mean squared errors. Finally, the results are applied to the estimation of unemployment proportions in Spanish domains.

156 IN VITRO DEVELOPMENT OF BOVINE MORULAE PRODUCED AND/OR CULTURED WITH ACTIVIN

We reported that the presence of activin during in vitro culture improves embryo development without changing the cell distribution in the blastocyst (Díez et al. 2009 AETE in press). In the present work, we aimed to analyze the morula stage as a putative milestone to activin exert differential effects. Day -5 morulae were produced with IVMFC oocytes from abattoir ovaries, using SOF with amino acids, myo-inositol, and 3 g L-1 of BSA as a culture medium. Embryo culture contained 10 ng mL-1 or 0 ng mL-1 of activin from Day -3 to Day -5. Early morulae (n = 543 out of 1099 cultured oocytes) were selected and subsequently cultured with or without 10 ng mL-1 of activin up to Day -8. Embryo development was daily monitored and cells differentially counted in Day -8 expanded blastocysts. (Thouas et al. 2001 Reprod. Biomed. 2001 3, 25-29). Data were analyzed by general linear model and presented as least squares means ± SEM. Activin from Days 3 to 5 did not change Day -5 morulae rates (P > 0.8). In morulae produced without activin (Days 5 to 8 and control), a treatment with activin from Days 5 to 8 improved total blastocyst rates v. controls, both in Day -7 and Day -8 (50.9 ± 3.6 v. 32.6 ± 3.6 and 60.8 ± 2.9 v. 42.3 ± 2.9, respectively; P < 0.01). Similarly, Day -7 expansion rates with activin (Days 5 to 8) were higher than controls (14.6 ± 1.8 v. 8.6 ± 1.8; P < 0.03). However, the above effects were not the same as those observed in morulae produced with activin (Days 3 to 5 and Days 3 to 8), where blastocyst development between activin treatment and controls only significantly differed in expansion rates on Day -7 (14.9 ± 1.8 v. 5.8 ± 1.8, respectively; P < 0.03). Morulae treated with activin (Days 5 to 8) yielded Day -7, total and expanded blastocyst rates, higher than morulae produced with activin (Days 3 to 5) (50.9 ± 3.6 v. 37.4 ± 3.6 and 14.6 ± 5.8 v. 5.8 ± 1.8, respectively; P < 0.03). Expansion rates on Day -8 were numerically higher within morulae produced and/or treated with activin (Days 3 to 8, Days 5 to 8, and Days 3 to 5) (values between 26.7 ± 2.6 and 27.4 ± 2.6) than in controls without activin at any time (19.2 ± 2.6) (P > 0.05). Trophectoderm (TE) cell numbers were reduced in embryos produced and/or treated with activin (Days 3 to 8, Days 3 to 5, and Days 5 to 8) (values between 109.4 ± 7.6 and 115.3 ± 7.9) as compared with untreated controls (141.2 ± 10.1) (P < 0.05). In morulae produced without activin, total cell counts were lower with activin being present from Day -5 to Day -8 (154.0 ± 8.8 v. 128.4 ± 7.2; P < 0.05). Inner cell mass (ICM) and ICM/total cell ratio were not affected by the presence of activin (P > 0.05). Activin did not change Day -5 morulae rates, although subsequent blastocyst development was in part affected by the presence of activin before the morula stage. Interestingly, improvements in blastocyst development, including expansion rates, triggered by activin led to reduced TE and unaltered ICM cell counts, suggesting that activin inhibits TE differentiation. Support: Cajastur (B. Trigal). MCINN: M. Muñoz (RYC08-03454); D. Martín (PTA2007-0268-I); INIA (I. Molina); Project HF2007-0126.

351 POLARIZED LIGHT MICROSCOPY: DETECTION OF MICROTUBULES AND ITS EFFECTS ON THE VIABILITY OF IN VITRO-MATURED PORCINE OOCYTES

The meiotic spindle in the oocyte is composed of microtubules and plays an important role during chromosome alignment and separation at meiosis. Polarized light microscopy (PLM) is used as a tool in human and, recently, in farm animals assisted reproductive technologies. PLM could be useful for a non-invasive evaluation of the meiotic spindle. The objectives of the present study were to assess the efficiency of PLM to detect microtubule-polymerized protein within in vitro-matured porcine oocytes and to examine the effects of PLM on the oocyte developmental competence. Cumulus-oocyte complexes from slaughterhouse ovaries were matured in vitro for 42 h as described by Gil et al. (2004 Theriogenology 62, 544-552). In the first experiment, a total of 97 oocytes from 6 replicates were placed individually in 10-μL drops of TCM-199-Hepes-FCS in a glass Petri dish. PLM was used to detect the presence of polymerized protein which could be forming a meiotic spindle. The presence of polymerized protein and a meiotic spindle was confirmed in individual oocytes by inmunostaining and chromatin detection as described by Morató et al. (2008 Mol. Reprod. Dev. 75, 191-201). In the second experiment, a total of 160 oocytes from 4 replicates were exposed or not (controls) to PLM for 10 minutes. Thereafter, the oocytes were parthenogenetically activated and cultured in vitro. Cleavage rate, total blastocyst rate, expanded blastocyst rate on Day 7 and total cell numbers in expanded blastocysts were assessed. Data were analyzed by GLM procedure of SAS. There was a positive correlation (r = 1; P < 0.0001) between the signal obtained by PLM and the presence of microtubule-polymerized protein as confirmed by inmunostaining. A positive PLM signal was detected in 98.9% of the oocytes. A barrel-shape spindle was observed in 94.8% of the individual samples by inmunostaining and all of these oocytes were positive to PLM. Moreover, oocytes exposed to PLM did not differ significantly from controls on cleavage rate (83.7 ± 1.5 v. 84.4 ± 1.5), total blastocyst rate (36.9 ± 3.6 v. 41.2 ± 3.6) and expanded blastocyst rate on Day 7 (21.9 ± 1.7 v. 26.2 ± 1.7), respectively. There were also no differences in total cell numbers counted in expanded blastocysts (32.8 ± 2.6 v. 35.6 ± 2.5). These results indicate that polarized light microscopy did not exert detrimental effects on porcine oocyte developmental competence and it seems an efficient system to detect polymerized protein in in vitro-matured porcine oocytes. Grant support: INIA: RZ2007-00013-00-00. I. Molina, M. Muñoz, B. Trigal and D. Martín are sponsored by INIA, RYC08-03454, Cajastur and PTA2007-0268-I, respectively.

Biogeographical origin and varicella risk in the adult immigration population in Catalonia, Spain (2004-2006)

Immigrants to the European Union may have a higher susceptibility to varicella-zoster virus primo-infection than the indigenous population. There is no evidence as yet that this is caused by genetic or social factors. Therefore, susceptibility could be due to a lesser transmission of the virus in their ecosystems of origin. A multicentre observational study was performed from July 2004 to June 2006 in four primary healthcare centres in Catalonia, Spain, monitoring varicella incidences and comparing standardised incidence rates and standardised rate ratios among different populations classified according to their biogeographical origin (holarctic, Asian paleotropical, African paleotropical or neotropical). Overall, 516 varicella cases were recorded. The standardised incidence rates per 1,000 inhabitants per year were: holarctic: 2.17 (95% confidence interval (CI): 1.95-2.39); autochthonous 2.26 (95% CI: 2.03-2.49); immigrants 3.59 (95% CI: 2.92-4.26); neotropical 4.50 (95% CI: 3.28-5.71); non-holarctic 5.38 (95% CI: 4.27-6.14); Asian paleotropical 7.03 (95% CI: 4.77-9.28); and African paleotropical 7.05 (95% CI: 1.12-23.58). The difference to the autochthonous population was greatest in immigrants of neotropical origin (standardised rate ratio = 2.07 (95% CI: 1.61-2.64) or 4.5 excess cases per 1,000 inhabitants per year) and Asian paleotropical origin (standardised rate ratio = 3.24 (95% CI: 2.47-4.11) or 9.6 excess cases per 1,000 inhabitants per year). Biogeographical origin may therefore account for the vulnerability of certain immigrant populations to varicella, in particular those from Asian paleotropical (Indostan and Southest Asia) and neotropical (South America and the Caribbean) ecosystems. Vaccination of immigrants at high risk (fertile women, healthcare workers) could be recommendable.

[Role of decompressive craniectomy in brain injury patient]

Second level therapeutic maneuvres for controlling intracranial hypertension (ICH) proposed by the European Brain Injury Consortium and the American Association of Neurological Surgeons include barbiturates, moderate hypothermia and decompressive craniectomy (DC). However, neither barbiturates nor hypothermia have been demonstrated to improve its outcome. DC could be a therapeutic option in the management of ICH without intracerebral masses. Therefore, our goal has been to review and analyze the clinical usefulness of DC in patients with brain injury in an attempt to deal with some concerns of the critical care physicians. Can DC improve patient outcome? Currently, there are no randomized and controlled clinical trials supporting or rejecting the practice of DC in adults. Most published reports provide level II of evidence. However, most of those studies have shown that the outcome is better in patients with DC. When should DC be performed? It should be performed early to prevent ICH from occurring more than 12 hours. What are the effects of DC on intracranial pressure and brain oxygenation? In most patients, ICP can be maintained below 25 mmHg after a DC. However, to improve brain oxygenation (PtiO(2)), the probe must be placed in the healthy area of the most severely damaged cerebral hemisphere. What is the suggested surgical procedure? Frontal-subtemporal-parietal-occipital craniectomies, including enlargement of the dura by duroplasty. And finally, what are the current contraindications of DC? Glasgow Coma Scale score 3 points post-resuscitation states with dilated and arreactive pupils, age > 65 years old, ICH > 12 hours, persistent (a-yv)DO(2) < 3.2% or PtiO(2) < 10 mmHg maintained from the moment of admission.