A novel strategy for the quantify of emerging isomeric pollutants belonging to the dihydroxybenzene family for environmental sample monitoring by amperometric detection.

This study introduces an innovative approach for quantifying isomeric pollutants utilizing an amperometric sensor. The determination of the isomers hydroquinone and catechol is based on the use of a glassy carbon electrode modified with Cu@PtPd/C nanoparticles (Cu@PtPd/C/GCE) in core-shell form, showing significant electrocatalytic activity in the oxidation of the later compounds. The determination was carried out at two different potentials: one at which where only hydroquinone is oxidized, and another in which where both hydroquinone and catechol are oxidized. Using these potentials, two calibration curves were built, one for the quantification of hydroquinone and the other for both isomers. Subsequently, the quantification of catechol was performed using a strategy based on the calculation of a difference using the information collected in the first step. The experiments using hydrogen peroxide as a redox probe demonstrate a clear synergistic effect in the catalytic reduction of hydrogen peroxide at -0.100 V, when Pt, Pd and Cu are incorporated into the core-shell nanostructure. The best performance was achieved with Cu@PtPd/C/GCE 1.00 mg mL-1. For the selected sensor, the analytical parameters are very competitive compared to similar devices reported in recent years for hydroquinone and catechol, with comparable linearity ranges of 0.010-0.200 mmol L-1 (hydroquinone) and 0.005-0.500 mmol L-1 (catechol), low limits of detection (LODs) of 14.0 nmol L-1 (S/N = 3.3) and 1.75 nmol L-1 (S/N = 3.3) for hydroquinone and catechol. The resulting sensor platform has been successfully applied for the quantification of hydroquinone and catechol in river and tap water and could be a promising candidate for environmental monitoring and drinking water safety.

Selective Detection of Paraquat in Adulterated and Complex Environmental Samples Using Raman Spectroelectrochemistry.

Growing demand for pesticides has created an environment prone to deceptive activities, where counterfeit or adulterated pesticide products infiltrate the market, often escaping rapid detection. This situation presents a significant challenge for sensor technology, crucial in identifying authentic pesticides and ensuring agricultural safety practices. Raman spectroscopy emerges as a powerful technique for detecting adulterants. Coupling the electrochemical techniques allows a more specific and selective detection and compound identification. In this study, we evaluate the efficacy of spectroelectrochemical measurements by coupling a potentiostat and Raman spectrograph to identify paraquat, a nonselective herbicide banned in several countries. Our findings demonstrate that applying -0.70 V during measurements yields highly selective Raman spectra, highlighting the primary vibrational bands of paraquat. Moreover, the selective Raman signal of paraquat was discernible in complex samples, including tap water, apple, and green cabbage, even in the presence of other pesticides such as diquat, acephate, and glyphosate. These results underscore the potential of this technique for reliable pesticide detection in diverse and complex matrices.

Investigating layer-by-layer films of carbon nanotubes and nickel phthalocyanine towards diquat detection.

The indiscriminate use of pesticides makes us susceptible to the toxicity of these chemical compounds, which may be present in high quantities in our food. It is crucial to develop inexpensive and rapid methods for determining these pesticides for government control or even for the general population. In this study, we investigated the fabrication of self-assembled LbL films using multi-walled carbon nanotubes (MWCNT) and nickel tetrasulphonated phthalocyanine (NiTsPc) as an electrochemical sensor for the herbicide Diquat (DQ). The Layer-by-Layer (LbL) assembly of the (MWCNT/NiTsPc) film was examined, along with its structural and morphological characteristics. The effect of the number of layers in DQ detection was evaluated by cyclic voltammetry, followed by the detection through differential pulse voltammetry. The achieved limit of detection was 9.62 × 10-7 mol L-1. A ~ 30% decrease in sensitivity was observed in the presence of Paraquat, a banned herbicide and electrochemical interferent due to the structural similarities, which is regularly neglected in the most published studies. The sensor was tested in real samples, demonstrating a recovery of 98.5% in organic apples.

Impact of the ´Alforja Educativa' on Ecuadorian schoolchildren's knowledge of bacteria, antibiotics, and antibiotic resistance, a pretest-posttest study.

BACKGROUND: Widespread use of antibiotics disrupts the balance in the microbial world and promotes development and spread of antibiotic resistant bacteria. Educational initiatives are important as part of strategies to mitigate antibiotic resistance. The Alforja Educativa is an innovative educational program developed in Ecuador with the aim to teach schoolchildren about antibiotic use and antibiotic resistance. The program places antibiotic resistance within a broader frame of health, well-being, and ecological awareness, highlighting the importance to maintain balance in the microbial world. The objective of this study was to evaluate the effect of the Alforja Educativa on knowledge about bacteria, antibiotics and antibiotic resistance amongst fifth and sixth grade Ecuadorian schoolchildren. METHODS: This pretest-posttest intervention study was conducted between April and June 2017 and comprised fifth and sixth grade schoolchildren from 20 schools in Cuenca, Ecuador, recruited by purposeful sampling. The Alforja Educativa was implemented over twelve 80-minute sessions by trained university students. Schoolchildren's knowledge was assessed before and after participation in the educational program using a structured questionnaire. A mean total score, the proportion of correct responses for each individual knowledge-based question, as well as correct responses for each of the multiple-choice options of the knowledge-based questions were calculated for the pretest and posttest. RESULTS: A total of 1,257 schoolchildren participated in the Alforja Educativa program, of which 980 (78%) completed both the pretest and posttest. Overall, the mean total knowledge score increased from pretest to posttest (2.58/7.00 vs. 3.85/7.00; CI = 0.5, p < 0.001). After participation in the program, the proportion of schoolchildren that correctly identified that bacteria can be both good and bad increased from 35.0 to 84.3%. In addition, scores increased for correctly identifying the meaning of antibiotic resistance (37.4-72.0%); how to prevent antibiotic resistance (63.2-74.6%); and for identifying the meaning of self-medication (46.3-54.3%). CONCLUSION: The Alforja Educativa was effective in improving the knowledge of participating schoolchildren about concepts related to bacteria, antibiotics and antibiotic resistance. The holistic perspective taken to explain the complex relationship between humans and bacteria, as well as the effect of antibiotics on the microbial world, may help provide a foundation for more sustainable antibiotic use.

Mental health outcomes in frontline healthcare workers in Brazil during the COVID-19 epidemic: Results of an online survey in four regions using respondent-driven sampling (RDS).

BACKGROUND: The COVID-19 pandemic overwhelmed health facilities and presented healthcare workers (HCWs) with a new infectious disease threat. In addition to a sanitary crisis, Brazil still had to face major political, economic, and social challenges. This study aimed to investigate mental health outcomes in frontline HCWs in different regions of the country and at different epidemic times. We also sought to identify the main risk factors associated with these outcomes. METHODS: A cross-sectional online survey using respondent-driven sampling was conducted to recruit physicians (n = 584), nurses (n = 997), and nurse technicians (n = 524) in 4 regions of Brazil (North, Northeast, Southeast, and South) from August 2020 to July 2021. We used standardized instruments to screen for common mental disorders (CMD)(SRQ-20), alcohol misuse (AUDIT-C), depression (PHQ-9), anxiety (GAD-7), and post-traumatic stress disorder (PTSD)(PCL-5). Gile's successive sampling estimator was used to produce weighted estimates. We created a three-cluster data set for each HCW category and developed a hierarchical regression model with three levels: individual characteristics; workplace-related aspects; COVID-19 personal experience. The impact of the epidemic moment on the outcomes was also studied. RESULTS: The prevalence of probable CMD was 26.8-36.9%, alcohol misuse 8.7-13.6%, depression 16.4-21.2%, anxiety 10.8-14.2%, and PTSD 5.9-8.0%. We found a stronger association between mental health outcomes and the following factors: history of psychiatric disorders, female gender, and clinical comorbidities (level 1); work overload and family isolation (level 2); sick leave (level 3). Epidemic variables, such as the number of deaths and trend of deaths by COVID-19, had almost no impact on the outcomes. CONCLUSION: An alarmingly high prevalence of depression and anxiety was found in Brazilian frontline HCWs. Individual factors were the most strongly associated with mental health outcomes. These findings indicate the need to develop programs that provide emotional support, identify professionals at risk and refer them to specialized treatment when necessary.

Seroprevalence of Dengue, Chikungunya and Zika at the epicenter of the congenital microcephaly epidemic in Northeast Brazil: A population-based survey.

BACKGROUND: The four Dengue viruses (DENV) serotypes were re-introduced in Brazil's Northeast region in a couple of decades, between 1980's and 2010's, where the DENV1 was the first detected serotype and DENV4 the latest. Zika (ZIKV) and Chikungunya (CHIKV) viruses were introduced in Recife around 2014 and led to large outbreaks in 2015 and 2016, respectively. However, the true extent of the ZIKV and CHIKV outbreaks, as well as the risk factors associated with exposure to these viruses remain vague. METHODS: We conducted a stratified multistage household serosurvey among residents aged between 5 and 65 years in the city of Recife, Northeast Brazil, from August 2018 to February 2019. The city neighborhoods were stratified and divided into high, intermediate, and low socioeconomic strata (SES). Previous ZIKV, DENV and CHIKV infections were detected by IgG-based enzyme linked immunosorbent assays (ELISA). Recent ZIKV and CHIKV infections were assessed through IgG3 and IgM ELISA, respectively. Design-adjusted seroprevalence were estimated by age group, sex, and SES. The ZIKV seroprevalence was adjusted to account for the cross-reactivity with dengue. Individual and household-related risk factors were analyzed through regression models to calculate the force of infection. Odds Ratio (OR) were estimated as measure of effect. PRINCIPAL FINDINGS: A total of 2,070 residents' samples were collected and analyzed. The force of viral infection for high SES were lower as compared to low and intermediate SES. DENV seroprevalence was 88.7% (CI95%:87.0-90.4), and ranged from 81.2% (CI95%:76.9-85.6) in the high SES to 90.7% (CI95%:88.3-93.2) in the low SES. The overall adjusted ZIKV seroprevalence was 34.6% (CI95%:20.0-50.9), and ranged from 47.4% (CI95%:31.8-61.5) in the low SES to 23.4% (CI95%:12.2-33.8) in the high SES. The overall CHIKV seroprevalence was 35.7% (CI95%:32.6-38.9), and ranged from 38.6% (CI95%:33.6-43.6) in the low SES to 22.3% (CI95%:15.8-28.8) in the high SES. Surprisingly, ZIKV seroprevalence rapidly increased with age in the low and intermediate SES, while exhibited only a small increase with age in high SES. CHIKV seroprevalence according to age was stable in all SES. The prevalence of serological markers of ZIKV and CHIKV recent infections were 1.5% (CI95%:0.1-3.7) and 3.5% (CI95%:2.7-4.2), respectively. CONCLUSIONS: Our results confirmed continued DENV transmission and intense ZIKV and CHIKV transmission during the 2015/2016 epidemics followed by ongoing low-level transmission. The study also highlights that a significant proportion of the population is still susceptible to be infected by ZIKV and CHIKV. The reasons underlying a ceasing of the ZIKV epidemic in 2017/18 and the impact of antibody decay in susceptibility to future DENV and ZIKV infections may be related to the interplay between disease transmission mechanism and actual exposure in the different SES.

Risk of adverse pregnancy and infant outcomes associated with prenatal Zika virus infection: a post-epidemic cohort in Central-West Brazil.

This study aimed to estimate the risks of adverse infant outcomes in the first year of life related to prenatal Zika virus (ZIKV) exposure. A prospective cohort of pregnant women with rash was recruited in Central-West Brazil in a post-epidemic period (January 2017 to April 2019). We evaluated participants' medical histories and performed ZIKV diagnostic testing using molecular (reverse transcription polymerase chain reaction [RT-PCR]) and serologic (immunoglobulin [Ig]M and plaque reduction neutralization tests [PRNT90]) assays. The ZIKV-positive group included both RT-PCR-confirmed cases as well as IgM and/or PRNT90-positive probable cases. Children were evaluated at birth and in the first 12 months of life. Transfontanellar ultrasound, central nervous system computed tomography, eye fundoscopy and retinography were performed. We estimated the absolute risk and 95% confidence interval (95% CI) of adverse infant outcomes among confirmed prenatally ZIKV-exposed children. Among 81 pregnant women with rash, 43 (53.1%) were ZIKV infected. The absolute risk of microcephaly among offspring of ZIKV-infected pregnant women was 7.0% (95% CI: 1.5-19.1), including the two cases of microcephaly detected prenatally and one detected postnatally. In total, 54.5% (95% CI: 39.8-68.7) of children in the ZIKV-exposed group had at least one ophthalmic abnormality, with the most frequent abnormalities being focal pigmentary mottling and chorioretinal atrophy or scarring. Our findings reinforce the importance of long-term monitoring of prenatally ZIKV-exposed children born apparently asymptomatic for Congenital Zika Syndrome.

High Incidence of Zika or Chikungunya Infection among Pregnant Women Hospitalized Due to Obstetrical Complications in Northeastern Brazil-Implications for Laboratory Screening in Arbovirus Endemic Area.

The diagnostic of arbovirus-related obstetric complications in high-risk pregnancy and childbirth care is challenging, especially in endemic areas. We conducted a prospective study to track active or recent Zika (ZIKV), dengue (DENV), or chikungunya (CHIKV) virus infection among hospitalized pregnant women (PW) with obstetric complications in a hospital at the epicenter of Zika outbreak and ZIKV-related microcephaly in Brazil. Clinical data and blood samples were collected at enrollment and 10 days after the admission of study participants, between October 2018 and May 2019. Further clinical data were extracted from medical records. Samples were screened by molecular and serological tests. Out of 780 participants, 93.1% (95% CI: 91.1-94.7%) presented previous DENV exposure (IgG). ZIKV, CHIKV, and/or DENV laboratory markers of recent or active infection were detected in 130 PW, yielding a prevalence of 16.6% (95% CI: 14.2-19.5%); 9.4% (95% CI: 7.4-11.7%), 7.4% (95% CI: 5.7-9.7%), and 0.38% (95% CI: 0.1-1.2%) of CHIKV, ZIKV, and DENV infections, respectively. Most ZIKV infections were detected by molecular assays (89.6%), while CHIKV infections were detected by serology (95.9%). Our findings highlight the need for arbovirus infections screening in PW with obstetrical complications, potentially associated to these infections in endemic areas regardless of the signs or symptoms suggestive of arboviral disease.

Titanium-Based Alloy Surface Modification with TiO2 and Poly(sodium 4-styrenesulfonate) Multilayers for Dental Implants.

Implant placement is an important repair method in dentistry and orthopedics. Increasing efforts have focused on optimizing the biocompatibility and osseointegration properties of titanium (Ti) and Ti-based alloys. In this work, Ti-based alloys were modified by the layer-by-layer (LbL) technique, which is a simple and versatile method for surface modification. The morphology and chemical structure of LbL films of poly(sodium 4-styrenesulfonate) (PSS) and Ti dioxide (TiO2) nanoparticles were first characterized employing ultraviolet-visible and Fourier-transform infrared spectroscopies as well as atomic force microscopy for further application in Ti-based alloy implants. The changes provoked by the LbL PSS/TiO2 film on the Ti-based alloy surfaces were then investigated by scanning electron microscopy and micro-Raman techniques. Finally, in vivo tests (immunolabeling and biomechanical analysis) performed with screw implants in rats suggested that PSS/TiO2 multilayers promote changes in both topography and chemical surface properties of the screw, providing beneficial effects for osteoblast activity. This simple and relatively low-cost growth process can open up possibilities to improve dental implants and, probably, bone implants in general.

Endocrine Dysfunction in Children with Zika-Related Microcephaly Who Were Born during the 2015 Epidemic in the State of Pernambuco, Brazil.

Congenital viral infections and the occurrence of septo-optic dysplasia, which is a combination of optic nerve hypoplasia, abnormal formation of structures along the midline of the brain, and pituitary hypofunction, support the biological plausibility of endocrine dysfunction in Zika-related microcephaly. In this case series we ascertained the presence and describe endocrine dysfunction in 30 children with severe Zika-related microcephaly from the MERG Pediatric Cohort, referred for endocrinological evaluation between February and August 2019. Of the 30 children, 97% had severe microcephaly. The average age at the endocrinological consultation was 41 months and 53% were female. The most frequently observed endocrine dysfunctions comprised short stature, hypothyroidism, obesity and variants early puberty. These dysfunctions occurred alone 57% or in combination 43%. We found optic nerve hypoplasia (6/21) and corpus callosum hypoplasia (20/21). Seizure crises were reported in 86% of the children. The most common-and clinically important-endocrine dysfunctions were pubertal dysfunctions, thyroid disease, growth impairment, and obesity. These dysfunctions require careful monitoring and signal the need for endocrinological evaluation in children with Zika-related microcephaly, in order to make early diagnoses and implement appropriate treatment when necessary.

Surgical findings in cryptorchidism in children with Zika-related microcephaly: a case series.

BACKGROUND: Complications in the urinary tract related to congenital Zika syndrome have recently been reported. One complication, cryptorchidism, has been reported by the Microcephaly Epidemic Research Group/MERG, in Pernambuco/Brazil. The present article describes for the first time the surgical findings in a case series of boys with Zika-related microcephaly and cryptorchidism, who underwent surgical testicular exploration as a contribution to better understand the possible mechanisms involved in gonads formation and descent. METHODS: A total of 7 children (11 testicular units), aged 3 to 4 years, were submitted to inguinal or scrotal orchidopexy for the treatment of palpable cryptorchidism between August 2019 and January 2020. Characteristics of the gonads and its annexes related to appendixes, testis-epididymis dissociation, gubernacular insertion, and associated hydroceles and/or hernias were described. Measures in centimetres were taken for volume calculate. RESULTS: We found a low prevalence of testicular and epididymal appendix (66.7%), a high prevalence of testis-epididymis dissociation (55.6%), low mean testicular volume for their ages (lower for older boys) and ectopic gubernacular insertion in all cases. There was no evidence of associated hydroceles and/or hernias in any case. No surgical complication was registered or reported, and all explored gonads were properly placed in the scrotal sac. CONCLUSIONS: We herein describe the surgical findings of these children's orchidopexies and discuss the possible mechanisms of viral action in embryogenesis and postnatal growth and development of the testes and annexes. These children need to be followed over time due to the higher risk of testicular atrophy and malignancy. Surgical timing seems to be relevant to avoid loss of testicular volume.

Pediatric neurodevelopment by prenatal Zika virus exposure: a cross-sectional study of the Microcephaly Epidemic Research Group Cohort.

BACKGROUND: The implications of congenital Zika Virus (ZIKV) infections for pediatric neurodevelopment and behavior remain inadequately studied. The aim of this study is to investigate patterns of neurodevelopment and behavior in groups of children with differening severities of ZIKV-related microcephaly and children with prenatal ZIKV exposure in the absence of microcephaly. METHODS: We conducted a cross-sectional study, nested in a cohort, of 274 children (aged 10-45 months) who were born during the peak and decline of the microcephaly epidemic in Northeast Brazil. Participants were evaluated between February 2017 and August 2019 at two tertiary care hospitals in Recife, Pernambuco, Brazil. We analyzed the children in four groups assigned based on clinical and laboratory criteria: Group 1 had severe microcephaly; Group 2 had moderate microcephaly; Group 3 had prenatal ZIKVexposure confirmed by maternal RT-PCR testing but no microcephaly; and Group 4 was a neurotypical control group. Groups were evaluated clinically for neurological abnormalities and compared using the Survey of Wellbeing of Young Children (SWYC), a neurodevelopment and behavior screening instrument validated for use in Brazil. Children with severe delays underwent further evaluation with an adapted version of the SWYC. RESULTS: Based on the SWYC screening, we observed differences between the groups for developmental milestones but not behavior. Among the 114 children with severe microcephaly of whom 98.2% presented with neurological abnormalities, 99.1% were 'at risk of development delay' according to the SWYC instrument. Among the 20 children with moderate microcephaly of whom 60% presented with neurological abnormalities, 65% were 'at risk of development delay'. For children without microcephaly, the percentages found to be 'at risk of developmental delay' were markedly lower and did not differ by prenatal ZIKV exposure status: Group 3 (N = 94), 13.8%; Group 4 (N = 46), 21.7%. CONCLUSIONS: Among children with prenatal ZIKV exposure, we found a gradient of risk of development delay according to head circumference. Children with severe microcephaly were at highest risk for delays, while normocephalic ZIKV-exposed children had similar risks to unexposed control children. We propose that ZIKV-exposed children should undergo first-line screening for neurodevelopment and behavior using the SWYC instrument. Early assessment and follow-up will enable at-risk children to be referred to a more comprehensive developmental evaluation and to multidisciplinary care management.

Health needs of indigenous Mayan older adults in Mexico and health services available.

Current data indicate that inequitable health service access is one of the major problems faced by indigenous people in Mexico and around the world. The aim of this study was to analyse the perceived health needs of indigenous older adults in a Mayan region of Mexico and the health services provided to address these needs. It used a qualitative design which explored health needs, perceptions of well-being, experiences with public health services and obstacles in accessing services through semi-structured interviews with 20 older adults, nine traditional healers and seven public healthcare providers from Mayan municipalities in southeastern Mexico during 2013-2014. We identified that cultural differences related to the language, values, beliefs and worldview of indigenous populations are ignored or incorporated only minimally by health services. The provision of services does not correspond to the health needs of indigenous Mayan older adults, and wide gaps still undermine their human rights and health status; despite the establishment of favourable regulations, healthcare services are organised for the non-indigenous population. The conditions of social vulnerability affecting indigenous older adults require that healthcare institutions incorporate an intercultural approach in order to improve the quality of care according to the necessities of the population.

Cryptorchidism in Children with Zika-Related Microcephaly.

The genitourinary tract was recently identified as a potential site of complications related to the congenital Zika syndrome (CZS). We provide the first report of a series of cryptorchidism cases in 3-year-old children with Zika-related microcephaly who underwent consultations between October 2018 and April 2019 as part of the follow-up of the children cohort of the Microcephaly Epidemic Research Group, Pernambuco, Brazil. Of the 22 males examined, eight (36.4%) presented with cryptorchidism. Among 14 undescended testis cases, 11 (78.6%) could be palpated in the inguinal region. Seven of the eight children had severe microcephaly. Conventional risk factors for cryptorchidism were relatively infrequent in these children. We hypothesize that cryptorchidism is an additional manifestation of CZS present in children with severe microcephaly. As in our cases, for most of the children, the testes were located in the inguinal region, and the possible mechanisms for cryptorchidism were gubernaculum disturbance or cremasteric abnormality.

Early epilepsy in children with Zika-related microcephaly in a cohort in Recife, Brazil: Characteristics, electroencephalographic findings, and treatment response.

OBJECTIVE: To estimate the incidence of epilepsy in children with Zika-related microcephaly in the first 24 months of life; to characterize the associated clinical and electrographic findings; and to summarize the treatment responses. METHODS: We followed a cohort of children, born during the 2015-2016 Zika virus (ZIKV) epidemic in Brazil, with congenital microcephaly and evidence of congenital ZIKV infection on neuroimaging and/or laboratory testing. Neurological assessments were performed at ≤3, 6, 12, 15, 18, 21, and 24 months of life. Serial electroencephalograms were performed over the first 24 months. RESULTS: We evaluated 91 children, of whom 48 were female. In this study sample, the cumulative incidence of epilepsy was 71.4% in the first 24 months, and the main type of seizure was infantile spasms (83.1%). The highest incidence of seizures occurred between 3 and 9 months of age, and the risk remained high until 15 months of age. The incidence of infantile spasms peaked between 4 and 7 months and was followed by an increased incidence of focal epilepsy cases after 12 months of age. Neuroimaging results were available for all children, and 100% were abnormal. Cortical abnormalities were identified in 78.4% of the 74 children evaluated by computed tomography and 100% of the 53 children evaluated by magnetic resonance imaging. Overall, only 46.1% of the 65 children with epilepsy responded to treatment. The most commonly used medication was sodium valproate with or without benzodiazepines, levetiracetam, phenobarbital, and vigabatrin. SIGNIFICANCE: Zika-related microcephaly was associated with high risk of early epilepsy. Seizures typically began after the third month of life, usually as infantile spasms, with atypical electroencephalographic abnormalities. The seizure control rate was low. The onset of seizures in the second year was less frequent and, when it occurred, presented as focal epilepsy.

Improving direct immunoassay response by layer-by-layer films of gold nanoparticles - Antibody conjugate towards label-free detection.

The conjugation of nanoparticles with antibodies has been successfully applied in sandwich immunoassays for detecting cancer biomarkers. However, two antibodies are necessary to perform such experiment, being one of them functionalized with a signal label for optical or electrochemical assay. This approach is time and cost consuming compared to direct label-free immunoassays. In this study, we propose the synthesis of gold nanoparticles conjugated to anti-PSA antibody to produce a label-free impedimetric immunosensors based on nanostructured Layer-by-Layer (LbL) films. Prostate-specific antigen (PSA) detection was performed by electrochemical impedance spectroscopy demonstrating a detection mechanism governed by Langmuir-Freundlich adsorption model. This strategy provided a significant sensitivity using 10-fold less antibody than conventional immunosensors, i.e. decreasing costs using a simple approach, with a limit of detection of 0.17 ng mL-1 and an analytical range of 0.1-20 ng mL-1 indicating that our sensor is potentially useful for clinical applications.

Layer-by-Layer Films of Gold Nanoparticles and Carbon Nanotubes for Improved Amperometric Detection of Cholesterol.

Distinct architectures of layer-by-layer (LbL) films made of carbon nanotubes and gold nanoparticles were investigated to serve as the matrix to immobilize cholesterol oxidase, with which cholesterol could be detected using amperometry. The gold nanoparticles were synthesized by metal reduction stabilized in poly(allylamine hydrochloride) (PAH) providing a stable AuNPs-PAH suspension, while multi-walled carbon nanotubes (CNTs) were functionalized with carboxylic groups to obtain an aqueous suspension. The LbL films were deposited on ITO, with a cushion film of PAH and poly(vinyl sulfonic acid) (PVS). Owing to the synergy between CNTs and AuNPs, the electrode ITO/(PAH/PVS)2 (AuNPs-PAH/CNTs)10 was selected for immobilization of cholesterol oxidase (ChOx). This sensor could detect cholesterol with a limit of detection of 14.8 µmol L-1 and sensitivity of 36.47 (µA cm-2)·(mmol L-1)-1. It was also able to determine cholesterol in egg yolk with a recovery of 97.7%.

Perinatal analyses of Zika- and dengue virus-specific neutralizing antibodies: A microcephaly case-control study in an area of high dengue endemicity in Brazil.

Laboratory confirmation of Zika virus (ZIKV) infection during pregnancy is challenging due to cross-reactivity with dengue virus (DENV) and limited knowledge about the kinetics of anti-Zika antibody responses during pregnancy. We described ZIKV and DENV serological markers and the maternal-fetal transfer of antibodies among mothers and neonates after the ZIKV microcephaly outbreak in Northeast Brazil (2016). We included 89 microcephaly cases and 173 neonate controls at time of birth and their mothers. Microcephaly cases were defined as newborns with a particular head circumference (2 SD below the mean). Two controls without microcephaly were matched by the expected date of delivery and area of residence. We tested maternal serum for recent (ZIKV genome, IgM and IgG3 anti-NS1) and previous (ZIKV and DENV neutralizing antibodies [NAbs]) markers of infection. Multiple markers of recent or previous ZIKV and DENV infection in mothers were analyzed using principal component analysis (PCA). At delivery, 5.6% of microcephaly case mothers and 1.7% of control mothers were positive for ZIKV IgM. Positivity for ZIKV IgG3 anti-NS1 was 8.0% for case mothers and 3.5% for control mothers. ZIKV NAbs was slightly higher among mothers of cases (69.6%) than that of mothers of controls (57.2%; p = 0.054). DENV exposure was detected in 85.8% of all mothers. PCA discriminated two distinct components related to recent or previous ZIKV infection and DENV exposure. ZIKV NAbs were higher in newborns than in their corresponding mothers (p<0.001). We detected a high frequency of ZIKV exposure among mothers after the first wave of the ZIKV outbreak in Northeast Brazil. However, we found low sensitivity of the serological markers to recent infection (IgM and IgG3 anti-NS1) in perinatal samples of mothers of microcephaly cases. Since the neutralization test cannot precisely determine the time of infection, testing for ZIKV immune status should be performed as early as possible and throughout pregnancy to monitor acute Zika infection in endemic areas.

Procesos educativos sobre enfermedad de Chagas con escolares de nivel básico de escuelas públicas de México / Educational processes on Chagas disease in schoolchildren from public schools in Mexico

Se presentan los cambios en conocimientos y prácticas sobre el vector y la enfermedad de Chagas con escolares de México posterior a una intervención educativa. La identificación del vector aumentó posterior a las sesiones educativas (pre=36,15% vs post=79,30%). Aumentaron los conocimientos acerca de la enfermedad de Chagas (30,90% vs 64,72%, valor de p< 0,0001) y de las acciones preventivas para evitar que el vector habite dentro de sus entornos (14,29% vs 61,81%, valor de p< 0,0001). Los escolares pueden jugar un papel fundamental en la prevención de esta problemática(AU)