[Prevalence of noncommunicable diseases and risk factors in rural population of San Luis, Argentina] / Prevalencia de enfermedades no transmisibles y factores de riesgo en población rural de San Luis, Argentina.

The objective of this study was to estimate the prevalence of diabetes mellitus (DM) and cardiovascular risk factors in a rural population in the province of San Luis, Argentina. Cross-sectional study developed between September and November 2017 with 18-year-old inhabitants and more than four towns in the Juan Martín de Pueyrredón department, San Luis. The participants answered questions by self-report on sociodemographic aspects, habits, psychosocial and risk factors for non-communicable diseases; physical measurements, FINDIRSC questionnaire and blood sample extraction were performed. Univariate estimates stratified by sex with their 95% confidence interval (95%CI) were obtained. We worked with sample expansion factors; crude and adjusted prevalences were calculated. The population consisted of 424 men (52.5%, 95%CI: 46.0-58.9) and 384 women (47.5%, 95%CI: 41.1-54.0). The adjusted prevalences for both sexes (by self-report) were: DM 11.8% (95%CI: 8.2-15.4); arterial hypertension (AHT): 35.5% (95% CI: 31.0-40.1); high cholesterol: 20.3% (CI 16.0-24.7). Males had significantly higher desirable HDL cholesterol and elevated blood pressure than females; women abdominal obesity in greater magnitude. 16.4% (95% CI: 11.0 - 23.6) had a high-very high risk of developing type 2 DM in the next 10 years. The adjusted prevalences of DM, hypertension, and high cholesterol were lower than those of the urban population of the province of San Luis. We highlight the pioneering contribution of this work to the knowledge of the health profile of rural communities in Argentina.

El objetivo de este estudio fue estimar la prevalencia de diabetes mellitus (DM) y factores de riesgo cardiovascular en una población rural de la provincia de San Luis, Argentina. Estudio transversal desarrollado entre septiembre y noviembre de 2017 con habitantes de 18 años y más de cuatro localidades del departamento Juan Martín de Pueyrredón, San Luis. Los participantes respondieron preguntas por autorreporte sobre aspectos sociodemográficos, hábitos, factores psicosociales y de riesgo para enfermedades no transmisibles; se realizaron mediciones físicas, cuestionario FINDIRSC y extracción de muestras de sangre. Se obtuvieron estimaciones univariadas estratificadas por sexo con su intervalo de confianza del 95% (IC95%). Se trabajó con factores de expansión de la muestra; se calcularon prevalencias crudas y ajustadas. La población estuvo constituida por 424 varones (52,5%, IC95%: 46,0-58,9) y 384 mujeres (47,5%, IC95%: 41,1-54,0). Las prevalencias ajustadas para ambos sexos (por autorreporte) fueron: DM 11,8% (IC95%: 8,2-15,4); hipertensión arterial (HTA): 35,5% (IC95%: 31,0-40,1); colesterol elevado: 20,3% (IC 16,0-24,7). Los varones tuvieron colesterol HDL deseable y tensión arterial elevada en una proporción significativamente superior a las mujeres; las mujeres obesidad abdominal en mayor magnitud. El 16,4 % (IC95%: 11,0 - 23,6) ostentó riesgo alto-muy alto de desarrollar DM tipo 2 en los próximos 10 años. Las prevalencias ajustadas de DM, HTA y colesterol elevado fueron inferiores a la de la población urbana de la provincia de San Luis. Destacamos la contribución pionera de este trabajo al conocimiento del perfil de salud de las comunidades rurales de Argentina.

Epidemiological study of non-communicable diseases in the rural population of San Luis, Argentina. Methodological aspects / [Estudio epidemiológico sobre enfermedades no transmisibles en población rural de San Luis, Argentina. Aspectos metodológicos]

Objective: to describe the methodological aspects of the first epidemiological study on the profile of non-communicable diseases (NCDs) in rural areas of Argentina carried out in 2017. Methods: A cross-sectional design was used. The reference population was the inhabitants of 18 years and over from the towns of Beazley, Zanjitas, Alto Pelado and Cazador, Juan M. de Pueyrredón department, San Luis province, Argentina. According to the latest census source, the number of inhabitants of that age group was 808 inhabitants. All homes in each locality were visited; All subjects who met the inclusion criteria were invited to participate. The research consisted of two phases: application of a self-report questionnaire in the home, followed by physical measurements, a FINDIRSC questionnaire (Finnish Diabetes Risk Score) and biochemical determinations. The data were dumped into a database in Epi Info 7. The statistical processing and analysis was performed in R 3.5.2 language. Results: 375 survey records with complete data were obtained, which represented 46.41% of the registered population according to census source; 252 performed laboratory analysis (67.20%) and 250 physical examination (66.67%). Participants in the survey phase exhibited characteristics similar to those who completed all stages of the investigation for most of the characteristics studied. Conclusions: this research was pioneer in generating knowledge about the NCD profile in the rural population of Argentina. It is expected to constitute an input for the planning of prevention policies, taking into account the local particularities.

Objetivo: describir los aspectos metodológicos del primer estudio epidemiológico sobre el perfil de enfermedades no transmisibles (ENT) en áreas rurales de Argentina llevado a cabo en 2017. Métodos: Se utilizó un diseño transversal. La población de referencia fueron los habitantes de 18 años y más de las localidades de Beazley, Zanjitas, Alto Pelado y Cazador, departamento Juan M. de Pueyrredón, provincia de San Luis, Argentina. El número de habitantes de esa franja etaria, según la última fuente censal, era de 808 habitantes. Se visitaron todas las viviendas de cada localidad; se invitó a participar a todos los sujetos que cumplieran con los criterios de inclusión. La investigación se conformó en dos fases: aplicación de cuestionario por autorreporte en la vivienda, seguida de mediciones físicas, cuestionario FINDIRSC (Finnish Diabetes Risk Score) y determinaciones bioquímicas. Los datos fueron volcados en una base de datos en Epi Info 7. El procesamiento y análisis estadístico se realizó en lenguaje R 3.5.2. Resultados: se obtuvieron 375 registros de encuestas con datos completos, que representó el 46.41% % de la población registrada según fuente censal; 252 realizaron análisis de laboratorio (67,20%) y 250 examen físico (66,67%). Los participantes de la fase de encuesta exhibieron características similares a aquellos que completaron todas las etapas de la investigación para la mayoría de las características estudiadas. Conclusiones: esta investigación fue pionera en generar conocimiento sobre el perfil de ENT en población rural de Argentina. Se espera que constituya un insumo para la planificación de políticas de prevención teniendo en cuenta las particularidades locales.

Development of an indirect competitive enzyme-linked immunosorbent assay applied to the Botrytis cinerea quantification in tissues of postharvest fruits.

BACKGROUND: Botrytis cinerea is a phytopathogenic fungus responsible for the disease known as gray mold, which causes substantial losses of fruits at postharvest. This fungus is present often as latent infection and an apparently healthy fruit can deteriorate suddenly due to the development of this infection. For this reason, rapid and sensitive methods are necessary for its detection and quantification. This article describes the development of an indirect competitive enzyme-linked immunosorbent assay (ELISA) for quantification of B. cinerea in apple (Red Delicious), table grape (pink Moscatel), and pear (William's) tissues. RESULTS: The method was based in the competition for the binding site of monoclonal antibodies between B. cinerea antigens present in fruit tissues and B. cinerea purified antigens immobilized by a crosslinking agent onto the surface of the microtiter plates. The method was validated considering parameters such as selectivity, linearity, precision, accuracy and sensibility. The calculated detection limit was 0.97 µg mL-1 B. cinerea antigens. The immobilized antigen was perfectly stable for at least 4 months assuring the reproducibility of the assay. The fungus was detected and quantified in any of the fruits tested when the rot was not visible yet. Results were compared with a DNA quantification method and these studies showed good correlation. CONCLUSIONS: The developed method allowed detects the presence of B. cinerea in asymptomatic fruits and provides the advantages of low cost, easy operation, and short analysis time determination for its possible application in the phytosanitary programs of the fruit industry worldwide.

A microfluidic device based on a screen-printed carbon electrode with electrodeposited gold nanoparticles for the detection of IgG anti-Trypanosoma cruzi antibodies.

In this article we report the development of an integrated microfluidic system coupled to a screen-printed carbon electrode (SPCE) applied to the quantitative determination of IgG specific antibodies present in serum samples of patients that suffer from Chagas disease. This relevant parasitic infection caused by the hemoflagellate protozoan Trypanosoma cruzi represents a major public health concern in Latin America. In order to perform the detection of mentioned antibodies, SPCE coupled to a microfluidic device was modified by electrodeposition of gold nanoparticles (AuNPs) and functionalized with Trypanosoma cruzi proteins from epimastigote membranes. The developed microfluidic immunosensor with immobilized T. cruzi proteins on the SPCE surface was successfully applied in the detection of specific IgG anti-T. cruzi antibodies, which were allowed to react immunologically with immobilized T. cruzi antigen. After that, labelled antibodies were quantified through the addition of horseradish peroxidase (HRP) enzyme-labeled secondary antibodies specific to human IgG, using 4-tert-butylcatechol (4-TBC) as enzymatic mediator. HRP in the presence of hydrogen peroxide (H(2)O(2)) catalyzes the oxidation of 4-TBC whose back electrochemical reduction was detected on a modified electrode at -100 mV. The calculated detection limit for electrochemical detection was 3.065 ng mL(-1) and the intra- and inter-assay coefficients of variation were below 6.95%.

Use of multiple sequential injections of equal volumes to determine the apparent binding constant for antibody-antigen complexes by capillary electrophoresis.

A new modified version of the well-known flow-through partial-filling technique [viz. multiple sequential injection of equal volumes (MSI-EV) of neutral marker, antigen (Ag) and antibody (Ab)] was used to calculate the apparent binding constant (Ka) of monoclonal Ab (mAb) and polyclonal Ab (pAb) to their specific antigens (Ags). Such a constant is very important in immunoassays. The procedure involves the sequential injection of small, identical volumes of a neutral marker (dimethyl sulfoxide, DMSO), an Ag and an Ab into a capillary column for electrophoresing. The apparent Ka values thus obtained from a Scatchard plot were 0.76+/-0.15 mg(-1) mL for the complex of anti-canine Immunoglobulin G (IgG) as mAb and canine IgG as Ag, and 0.79+/-0.14 mg(-1) mL for that between anti-human IgG as pAb and human IgG as Ag. These values are of the same order to those provided by indirect competition enzyme-linked immunosorbent assay (ELISA) (viz. 0.42+/-0.28 mg(-1) mL for the mAb-Ag complex and 0.81+/-0.09 mg(-1) mL for the pAb-Ag complex). The high sensitivity of the MSI-EV-CE technique affords the detection of very low concentrations of Ab.

Immuno-column for on-line quantification of human serum IgG antibodies to Helicobacter pylori in human serum samples.

This study report an human serum IgG antibodies to Helicobacter pylori quantitation procedure based on the multiple use of an immobilized H. pylori antigen on an immuno-column incorporated into an a flow-injection (FI) analytical system. The immuno-adsorbent column was prepared by packing 3-aminopropyl-modified controlled-pore glass (APCPG) covalently linking H. pylori antigens in a 3-cm of Teflon tubing (0.5 i.d.). Antibodies in the serum sample are allowed to react immunologically with the immobilized H. pylori antigen, and the bound antibodies are quantified by alkaline phosphatase (AP) enzyme-labeled second antibodies specific to human IgG. p-Aminophenyl phosphate (pAPP) was converted to p-aminophenol (pAP) by AP and an electroactive product was quantified on glassy carbon electrode (GCE) modified with multiwall carbon nanotubes (MWCNT) (GCE-CNTs) at 0.30 V. The total assay time was 25 min. The calculated detection limits for amperometric detection and the ELISA procedure are 0.62 and 1.8 UmL(-1), respectively. Reproducibility assays were made using repetitive standards of H. pylori-specific antibody and the intra- and inter-assay coefficients of variation were below 5%. The immuno-affinity method showed higher sensitivity and lower time-consumed, demonstrate its potential usefulness for early assessment of human serum immunoglobulin G (IgG) antibodies to H. pylori.

Integrated microfluidic systems with an immunosensor modified with carbon nanotubes for detection of prostate specific antigen (PSA) in human serum samples.

This paper describes the development of an immunosensor coupled to glassy carbon electrode (GCE) modified with multiwall carbon nanotubes (MWCNT) (CNT-GCE) integrated with microfluidic systems for rapid and sensitive quantification of prostate specific antigen (PSA) in human serum samples. Mouse monoclonal (5G6) to PSA antibodies were immobilized on a rotating disk. PSA in the serum sample are allowed to react immunologically with the immobilized anti-tPSA and horseradish peroxidase (HRP) enzyme-labeled second antibodies specific to PSA. HRP, in the presence of hydrogen peroxide (H(2)O(2)) catalyzes the oxidation of 4-tert-butylcatechol (4-TBC), whose back electrochemical reduction was detected on CNT-GCE at -0.15 V. The electrochemical detection can be done within 1 min and total assay time was 30 min. The calculated detection limits for electrochemical detection and the ELISA procedure are 0.08 and 0.5 microg L(-1), respectively and the intra- and inter-assay coefficients of variation were below 4.5%. The electrochemical immunosensor showed higher sensitivity and lower time consumed than the standard spectrophotometric detection ELISA method, which shows potential for detecting PSA in clinical diagnosis.

Sensitive determination of ciprofloxacin and norfloxacin in biological fluids using an enzymatic rotating biosensor.

The high sensitivity that can be attained using an enzymatic system and mediated by catechol has been verified by on-line interfacing of a rotating biosensor and continuous-flow/stopped-flow/continuous-flow processing. Horseradish peroxidase, HRP, [EC 1.11.1.7], immobilized on a rotating disk, in the presence of hydrogen peroxide catalyzed the oxidation of catechol, whose back electrochemical reduction was detected on glassy carbon electrode surface at -200mV. Thus, when ciprofloxacin (CF) or norfloxacin (NF) was added to the solution, these piperazine-containing compounds participate in Michael addition reactions with catechol to form the corresponding aminoquinone derivative, decreasing the peak current obtained in proportion with the increase of its concentration. CF was used as the model piperazine-containing compound for the study. The influence of indicator composition on the nature of the analytical response has been assessed through examining the electrochemical properties of three derivatives. Interference by electroactive species (ascorbate, urate, and tyrosine) and other physiological constituents (cysteine, glutathione) has also been assessed.

Speciation analysis of selenium in natural water using square-wave voltammetry after preconcentration on activated carbon.

A simple, accurate, sensitive and selective method was described for rapid determination of ultra-trace quantities of selenium. Selenium(IV) was collected on activated carbon (AC) after reduction to elemental Se by l-ascorbic acid. The collected selenium was then dissolved by oxidation reaction with bromate in acidic media and was indirectly determined through the bromide formation using square-wave voltammetry (OSWV). The total amount of Se(IV) and Se(VI) was collected on AC after its reduction by hydrazine. Selenium in the range 0.01-20 microg L(-1) could be determined by this method. The method was used to the determination of Se(IV) and Se(VI) in natural water with satisfactory results.

Penicillamine determination using a tyrosinase micro-rotating biosensor.

Tyrosinase [EC 1.14.18.1], immobilized on a rotating disk, catalyzed the oxidation of catechols to o-benzoquinone, whose back electrochemical reduction was detected on glassy carbon electrode surface at -150mV versus Ag/AgCl/NaCl 3M. Thus, when penicillamine (PA) was added to the solution, this thiol-containing compound participate in Michael type addition reactions with o-benzoquinone to form the corresponding thioquinone derivatives, decreasing the reduction current obtained proportionally to the increase of its concentration. This method could be used for sensitive determination of PA in drug and human synthetic serum samples. A linear range of 0.02-80 microM (r=0.999) was obtained for amperometric determination of PA in buffered pH 7.0 solutions (0.1 M phosphate buffer). The biosensor has a reasonable reproducibility (R.S.D.<4.0%) and a very stable amperometric response toward this compound (more than 1 month).

Enzymatic rotating biosensor for cysteine and glutathione determination in a FIA system.

The high sensitivity that can be attained using an enzymatic system and mediated by catechols has been verified by on-line interfacing of a rotating biosensor and continuous flow/stopped-flow/continuous-flow processing. Horseradish peroxidase, HRP, [EC 1.11.1.7], immobilized on a rotating disk, in presence of hydrogen peroxide catalyzed the oxidation of catechols, whose back electrochemical reduction was detected on glassy carbon electrode surface at -150mV. Thus, when l-cysteine (Cys) or glutathione (GSH) was added to the solution, these thiol-containing compounds participate in Michael addition reactions with catechols to form the corresponding thioquinone derivatives, decreasing the peak current obtained proportionally to the increase of its concentration. Cys was used as the model thiol-containing compound for the study. The highest response for Cys was obtained around pH 7. This method could be used to determine Cys concentration in the range 0.05-90muM (r=0.998) and GSH concentration in the range 0.04-90muM (r=0.999). The determination of Cys and GSH were possible with a limit of detection of 0.7 and 0.3nM, respectively, in the processing of as many as 25 samples per hour. Current response of the HRP-rotating biosensor is not affected by the oxidized form of GSH and Cys (glutathione disulfide, GSSG, and l-cystine, respectively), by sulfur-containing and alkyl-amino compounds such as methionine and lysine, respectively. The interferences from easily oxidizable species such as ascorbic acid and uric acid are lowest.

Enzymatic rotating biosensor for ciprofloxacin determination.

The high sensitivity that can be attained using an enzymatic system and mediated by catechol has been verified by on-line interfacing of a rotating biosensor and continuous flow/stopped-flow/continuous-flow processing. Horseradish peroxidase, HRP [EC 1.11.1.7], immobilized on a rotating disk, in the presence of hydrogen peroxide, catalyzed the oxidation of catechol, whose back electrochemical reduction was detected on a glassy carbon electrode surface at -200mV. Thus, when ciprofloxacin (CF) was added to the solution, this piperazine-containing compound participate in Michael addition reactions with catechol to form the corresponding piperazine-quinone derivatives, decreasing the peak current obtained, in proportion with the increase of its concentration. The highest response for CF was obtained around pH 7. This method could be used to determine CF concentration in the range of 0.02-65muM (r=0.999). The determination of CF concentration was possible with a detection limit of 0.4nM, in the processing of as many as 25 samples per hour. Application of this analysis to different pharmaceutical samples containing CF supports the utility of the HRP-rotating biosensor.

Multienzymatic-rotating biosensor for total cholesterol determination in a FIA system.

Fabrication of an amperometric-rotating biosensor for the enzymatic determination of cholesterol is reported. The assay utilizes a combination of three enzymes: cholesterol esterase (ChE), cholesterol oxidase (ChOx) and peroxidase (HRP); which were co-immobilizing on a rotatory disk. The method is developed by the use of a glassy carbon electrode as detector versus Ag/AgCl/3M NaCl in conjunction with a soluble-redox mediator 4-tert-butylcatechol (TBC). ChE converts esterified cholesterol to free cholesterol, which is then oxidized by ChOx with hydrogen peroxide as product. TBC is converted to 4-tert-butylbenzoquinone (TBB) by hydrogen peroxide, catalyzed by HRP, and the glassy carbon electrode responds to the TBB concentration. The system has integrated a micro packed-column with immobilized ascorbate oxidase (AAOx) that works as prereactor to eliminate l-ascorbic acid (AA) interference. This method could be used to determine total cholesterol concentration in the range 1.2muM-1mM (r=0.999). A fast response time of 2min has been observed with this amperometric-rotating biosensor. Lifetime is up to 25 days of use. The calculated detection limits was 11.9nM. Reproducibility assays were made using repetitive standards solutions (n=5) and the percentage standard error was less than 4%.

Continuous-flow/stopped-flow system for enzyme immunoassay using a rotating bioreactor: determination of Chagas disease.

The high sensitivity that can be attained using an immunoassays coupled to a rotating bioreactor with electrochemical detection mediated by [Os(bpy)2Cl(pyCOOH)]Cl, has been verified for the detection of Trypanozoma cruzi (T. cruzi), This protozoan parasite causes Chagas disease, affecting more than 18 million people in central and south America. Antibodies in the serum sample are allowed to react immunologically with whole homogenates of the parasite as antigen that are immobilized on a rotating disk. The bound antibodies are quantified by a horseradish peroxidase (HRP) enzyme labeled second antibodies specific to human IgG in presence of hydrogen peroxide using an osmium complex [Os(bpy)2Cl(pyCOOH)]Cl as enzymatic mediators. The amperometric measurement performed at 0.00 V versus Ag/AgCl can be done within 2 min and the analysis time does not exceed 23 min. The calculated detection limits was 0.01 mIU ml(-1). Reproducibility assays were made using repetitive serum of 0.182 mIU ml(-1) T. cruzi specific antibody (measured as the activity of the correspondent anti-serum's enzyme conjugated); the percentage standard error was less than 5%. The amperometric immunoreactors showed significantly higher sensitivity and lower time consumed than the standard spectrophotometric detection ELISA method.

Continuous-flow system for horseradish peroxidase enzyme assay comprising a packed-column, an amperometric detector and a rotating bioreactor.

The roles of chemical kinetics and mass transfer in three types of bioreactors (packed-column reactors, rotating disk bioreactors and amperometric detector), used with continuous-flow sample/reagent(s) processing, are discussed in detail. A normalized quantitative comparison between these types of reactors clearly shows that rotating disk reactors afford a significantly more efficient utilization of active sites and permit the effective utilization of very small amounts of biocatalysts. Horseradish peroxidase (EC 1.11.1.7), in presence of hydrogen peroxide catalyses the oxidation of [Os(bpy)(2)Cl(pyCOOH)]Cl. The electrochemical reduction back of this cosubstrate is detected on glassy carbon electrode surface at 0.00V. Furthermore, the critical effect of substrate and cosubstrate concentration on amperometric immunosensors construction in which HRP is used as an enzymatic label was studied.