Monetary valuation of unsorted waste: A shadow price approach.

Improving the management of municipal solid waste (MSW) is fundamental to promote circular economy and sustainability. Unsorted waste involves negative environmental impacts which often are ignored in economic feasibility studies due to its difficult valuation. In this study the shadow price of unsorted waste using the directional distance function was estimated. This methodological approach also allowed us to compute eco-efficiency scores of a set of municipalities in the provision of MSW services. The empirical application focused on a sample of 119 Chilean municipalities. The results showed that the average shadow price of unsorted waste was 297.66 €/ton which means that the environmental cost of left waste as unsorted was 297.66 € per ton. A regression tree model illustrated that population density, tourism intensity and the generation of waste per capita significantly influenced the shadow price of unsorted waste. Moreover, it was illustrated that Chilean municipalities were very inefficient in the management of MSW since the average eco-efficiency score was 0.272. The findings from this study reveal that additional and alternative policies should be adopted to improve the management of MSW and increase its recycling rate.

Factors influencing eco-efficiency of municipal solid waste management in Chile: A double-bootstrap approach.

Improving eco-efficiency in the provision of municipal solid waste plays an important role for a sustainable economy. Eco-efficiency of municipal solid waste service providers (MSWSPs) has been generally assessed using the conventional data envelopment analysis (DEA) method. However, this approach is sensitive to data noise and has no statistical properties. To overcome these limitations, in this paper, we adopt the double-bootstrap DEA model to derive robust eco-efficiency scores. This nonparametric method allows conducting statistical inference to explore environmental factors affecting the eco-efficiency of MSWSPs. The empirical approach focused on a sample of 298 MSWSPs in Chile, a middle-income country whose policies for promoting waste recycling are incipient. The results indicated that based on the bias-corrected eco-efficiency scores, the potential saving in costs and unsorted waste could be up to 37.8% on average to generate the same level of output (recycled waste). The findings showed that dealing with data noise and uncertainly is of great importance when conducting benchmarking analysis. The region where the municipality is located, tourism, population density and waste per capita are environmental variables that significantly influenced eco-efficiency of Chilean MSWSPs. Several policy implications are discussed based on the findings of this study.

The eco-efficiency of municipalities in the recycling of solid waste: A stochastic semi-parametric envelopment of data approach.

Eco-efficiency assessment of municipal solid waste (MSW) suppliers is a useful tool in the transition to a circular economy. Furthermore, it provides evidence of the economic and environmental performance of municipalities that can be used for decision-making and/or elaboration of regulatory policies. In this study, eco-efficiency scores were computed for a sample of 140 Chilean municipalities in the provision of MSW services. In doing so, the stochastic semi-parametric envelopment of data method was applied. It is a novel technique which overcomes the limitations of parametric (stochastic frontier analysis) and non-parametric (data envelopment analysis) methods previously employed to evaluate the eco-efficiency of MSW services. The average eco-efficiency of the 140 assessed municipalities was 0.332 which indicates that they could save 66.8% of their operational costs and recycling the same amount of waste. Moreover, 61.4% of the evaluated municipalities presented an eco-efficiency score which was lower than 0.4, whereas the other municipalities (38.6% of the sample) exhibited an eco-efficiency which raged between 0.4 and 0.80. Hence, none of the municipalities assessed was identified as eco-efficient which, implies that there is room for all municipalities to reduce operational costs in the management of MSW. Population density, tourism and location of the municipality were identified as factors influencing the eco-efficiency of the municipalities in MSW management.

Valp1, a Newly Identified Temperate Phage Facilitating Coexistence of Lysogenic and Non-Lysogenic Populations of Vibrio anguillarum.

Vibrio anguillarum is a pathogen for several fish and shellfish species. Its ecology is influenced by diverse factors, including bacteriophages. Here, we identify and characterize a new temperate bacteriophage (Valp1) of V. anguillarum. Valp1 is a myovirus with a 60 nm head and a 90 nm contractile tail. Its double-stranded DNA genome of 42,988 bp contains 68 genes, including a protelomerase gene, typical of telomeric phages. Valp1 inhibits the growth of the virulent strain of V. anguillarum PF4, while the derived lysogenic strain P1.1 presents a slight reduction in its growth but is not affected by the presence of Valp1. Both strains present similar virulence in a larval zebrafish (Danio rerio) model, and only slight differences have been observed in their biochemical profile. Co-culture assays reveal that PF4 and P1.1 can coexist for 10 h in the presence of naturally induced Valp1, with the proportion of PF4 ranging between 28% and 1.6%. By the end of the assay, the phage reached a concentration of ~108 PFU/mL, and all the non-lysogenic PF4 strains were resistant to Valp1. This equilibrium was maintained even after five successive subcultures, suggesting the existence of a coexistence mechanism between the lysogenic and non-lysogenic populations of V. anguillarum in conjunction with the phage Valp1.

A comprehensive assessment of energy efficiency of wastewater treatment plants: An efficiency analysis tree approach.

Wastewater treatment plants (WWTPs) are energy intensive facilities. Controlling energy use in WWTPs could bring substantial benefits to people and environment. Understanding how energy efficient the wastewater treatment process is and what drives efficiency would allow treating wastewater in a more sustainable way. In this study, we employed the efficiency analysis trees approach, that combines machine learning and linear programming techniques, to estimate energy efficiency of wastewater treatment process. The findings indicated that considerable energy inefficiency among WWTPs in Chile existed. The mean energy efficiency was 0.287 suggesting that energy use should cut reduce by 71.3 % to treat the same volume of wastewater. This was equivalent to a reduction in energy use by 0.40 kWh/m3 on average. Moreover, only 4 out of 203 assessed WWTPs (1.97 %) were identified as energy efficient. It was also found that the age of treatment plant and type of secondary technology played an important role in explaining energy efficiency variations among WWTPs.

Assessing eco-efficiency of wastewater treatment plants: A cross-evaluation strategy.

Evaluating the eco-efficiency of wastewater treatment plants (WWTPs) is crucial for enhancing environmental and economic performance in the water utility sector. Previous studies in this area estimated WWTP eco-efficiency through self-evaluation, which might have led to overestimation and biased policy recommendations. To address these issues, this study applies a cross-evaluation strategy, combining self-evaluation and peer-evaluation, to assess the eco-efficiency of WWTPs. The empirical application focuses on a sample of Spanish WWTPs, yielding the following key findings. Average eco-efficiency scores were 0.353 and 0.230, for self-evaluation and global peer-evaluation approaches, respectively, confirming the overestimation of eco-efficiency scores based on self-evaluation. If WWTPs were eco-efficient, they could potentially reduce greenhouse gas (GHG) emissions by up to 0.39 kg CO2eq/year. The application of reliable methods, such as peer-evaluation, for eco-efficiency assessment of WWTPs provides water regulators with a comprehensive understanding of the environmental and economic performance of WWTPs. This knowledge guides decision-making, policy development, and resource allocation, facilitating sustainable and efficient wastewater management practices.

Assessing the dynamic performance of water companies through the lens of service quality.

The measurement of performance within the water industry holds significant importance for policymakers, as it can help guide decision-making for future development and management initiatives. In this study, we apply data envelopment analysis (DEA) cross-efficiency techniques to evaluate the productivity change of the Chilean water industry during the years 2010-2018. Water leakage and unplanned interruptions are included in the analysis as quality of service variables. Moreover, we use cluster analysis and regression techniques to better understand what drives productivity change of water companies. The results indicate that the Chilean water industry is characterized by considerable high levels of inefficiency and low levels of productivity change. This is due to the existence of technical regress whereas gains in efficiency were small. Concessionary water companies were found to be more productive than full private and public water companies. Best and worst performers need to make efforts to reduce production costs and improve service quality. Other factors such as customer density and ownership type statistically affect productivity.

Eco-efficiency assessment under natural and managerial disposability: an empirical application for Chilean water companies.

Getting a good understanding regarding the economic and environmental performance of water utilities is of great importance to achieve the goal of an efficient and sustainable industry. In this study, we apply the range adjusted measure (RAM) data envelopment analysis (DEA) model to evaluate the integrated (production and environmental) efficiency of several water utilities located in Chile. Integrated efficiency is evaluated using the concepts of natural and managerial disposability. This approach further allows us to quantify the contribution of each input and undesirable product on efficiency scores. The results highlighted that the Chilean water industry showed high levels of production and environmental efficiency over time. Under natural disposability, water utilities could control production costs to reduce water leakage and unplanned water supply interruptions by 3.3% on average. Under managerial disposability, water utilities could further cut down undesirable outputs by 1.4% on average by adopting best managerial practices. On average, potential savings in operating costs, employment, water leakage, and unplanned water supply interruptions were higher for concessionary utilities as they showed slightly lower efficiency scores than full private utilities.

Energy efficiency of drinking water treatment plants: A methodological approach for its ranking.

Drinking water treatment systems (DWTSs) are energy intensive facilities, and are an example of the water-energy nexus. Benchmarking energy efficiency is a valuable tool for improving the economic and environmental performance of such facilities. Data envelopment analysis (DEA) is typically used to assess efficiency, allocating flexible weights (FSW) to variables that maximise energy efficiency scores for each DWTS (DEA-FSW). It means that different conditions are applied to each DWTS. Moreover, the DEA-FSW approach has finite discriminatory power which limits cross-unit comparison of energy efficiency hindering the benchmarking of DWTSs. To overcome these limitations, our study explored the effect of estimating the energy efficiency scores of DWTSs by allocating common sets of weights (CSW) within DEA (DEA-CSW). This approach was applied empirically on a sample of 146 DWTSs. Evaluated DWTSs had poor energetic performance based on both DEA-FSW and DEA-CSW estimates (low energy efficiency scores: 0.329 and 0.163, respectively). Even in the optimistic scenario, the average energy efficiency score was low (0.220), with potential electricity savings of 78 % by DWTPs when energy efficient. Unlike DEA-FSW, DEA-CSW allowed energy efficient DWTSs to be distinguished from the 146 facilities. Significant differences in the weights allocated to electricity and pollutants removed from raw water were reported for both approaches, and contributed to diverging energy efficiency scores. In conclusion, this study demonstrated the relevance of using suitable methods to generate comparable results for water companies, allowing the energy performance of DWTSs to be objectively evaluated for benchmarking purposes.

Understanding water-energy nexus in drinking water provision: An eco-efficiency assessment of water companies.

Understanding water-energy nexus in the provision of drinking water services is a challenge which has outstanding relevance in the current climatic emergency. Environmental efficiency and eco-efficiency assessment of water companies are two useful tools to address this challenge. In this study, we estimated hyperbolic and enhanced hyperbolic distance functions to compute the potential reduction in greenhouse gas (GHG) emissions and energy costs in the provision of drinking water. The empirical application focused on the English and Welsh water companies over 2011-2019. Average environmental efficiency and eco-efficiency scores were 0.920 and 0.962, respectively which indicates that water companies performed well but there is room for improvement. Moreover, due to the economies of scale, the cost of reducing GHG emissions was higher for water and sewerage companies than for water only companies. The results and conclusions of this study allow better understanding of the relationship between the provision of drinking water, energy costs and GHG emissions.

How much does it cost to collect recyclable and residual waste in medium-income countries? A case study in the Chilean waste sector.

Improper municipal solid waste (MSW) management leads to contamination of water, soil and air with negative impacts on human health. Moreover, not dealing with residual waste has huge implications for meeting circular economy targets. Understanding how much it costs could lead to a better quality of service and boost environmental sustainability. This study estimates an input distance function using econometric techniques to measure the technical efficiency of the MSW sector in Chile. This approach further allows us to estimate the shadow price of residual waste in terms of total costs. The results indicated that the average technical efficiency of the waste sector was 0.592. This means that the potential savings in costs and residual waste among municipalities could be at the level of 40.8%. Large divergences among municipalities were found since efficiency scores ranged between 0.029 and 0.863. It is found that for 53% of the municipalities evaluated, efficiency scores varied between 0.61 and 0.80. On average, the cost of reducing residual waste was 81.10 US $ per kilogram. This means that on average the cost of preventing one more kilogram of residual waste not being collected and recycled was 81.10 US $. It was also found that on average as population density increased, the shadow price of residual waste increased as well.Implications: The study provides a methodology that allows the policy makers to estimate the efficiency of the solid waste sector where limited available statistical data usually exists in developing and medium-income countries. They have the opportunity to understand what drives costs and identify the best and worst performers. This information is essential to develop local initiatives to enhance waste recycling and therefore, achieving the targets established at national level. Managers can also see if there are other operating factors that could influence performance such as population density. The proposed methodology allows integrating other exogenous variables that might be interesting to policy makers. For instance, a tourism index could be included in the assessment to evaluate whether tourism impacts on the efficiency of municipalities in the provision of municipal solid waste services and therefore, to analyze the implementation of an eco-tax for tourists.

Estimation of greenhouse gases shadow price in the English and Welsh water industry.

Moving to a more sustainable and low-carbon footprint urban water cycle is essential in the light of climate change. In this paper, we estimate the implicit cost of reducing greenhouse gas (GHG) emissions for several English and Welsh water companies from 2013 to 2019. Using econometric techniques, we compute the shadow prices of direct and indirect CO2 emissions associated with the provision of drinking water. This methodological approach also allows us to investigate the impact of a set of environmental variables on the costs of water companies and therefore on the costs of reducing GHG emissions. We then compute the returns to scale, technical change, and technical efficiency of the water companies. The empirical results show the following: (1) the average shadow price of CO2 across years was 0.114 £/kgCO2, which means that the English and Welsh water industry needs to spend an extra £0.114 in operating expenditure to prevent the emission of one kilogramme of CO2; (2) the cost of reducing GHG emissions is very variable among water companies and across years; (3) water taken from boreholes and average pumping head increases cost requirements and therefore the inefficiency of water companies; and (4) the water industry may lower its production costs and thus the costs of reducing GHG emissions by improving its daily operations and adopting new technologies. From a policy perspective, this study evidences that in the English and Welsh water industry, a market-based approach may be more suitable to reduce GHG emissions than a carbon tax policy.

Total factor productivity assessment of water and sanitation services: an empirical application including quality of service factors.

Assessing the productivity change of water companies provides relevant information for both water regulators and companies' managers. Past research has illustrated that different indicators and indexes have been applied although not all of them are equally reliable. Thus, this study evaluates the total factor productivity (TFP) change and its drivers employing the Luenberger-Hicks-Moorsteen productivity indicator (LHMPI) including, for the first time, quality of service variables as undesirable outputs. Moreover, unlike the previous studies, LHMPI was decomposed into three drivers; namely technical change, technical efficiency change and scale efficiency change. Our empirical application conducted on a sample of Chilean water companies over 2007-2018 embracing full private water companies (FPWCs) and concessionary water companies (CWCs). Results evidenced that, on average, TFP increased at an annual rate of 2.2%, mainly due to outputs rise. The main driver of productivity growth was scale efficiency change suggesting that adjustments in the water companies' scale of operations could lead to lower operational costs. It was also evidenced that FPWCs performed better than CWCs over the period analyzed.

Eco-Efficiency of the English and Welsh Water Companies: A Cross Performance Assessment.

Analyzing costs and greenhouse gas (GHG) emissions could be of great importance for the water utilities to supply water services in a healthy and sustainable manner. In this study, we measured the eco-efficiency of several water utilities in England and Wales by incorporating GHG as an undesirable output. For the first time, we evaluated the eco-efficiency of the water production process using robust cross-efficiency data envelopment analysis (DEA) techniques. The further use of clustering and regression techniques allowed us to better understand the drivers of eco-efficiency. The results showed that the mean eco-efficiency of the water sector was 0.748, which indicates that costs and GHG emissions could be reduced by 25.2% to generate the same level of output. Large water companies with high energy costs and levels of GHG emissions belonged to the less eco-efficient group. Environmental factors related to density, topography, and treatment complexity further impacted eco-efficiency. Finally, we linked our results to the regulatory cycle and discuss some policy implications.

Estimating the environmental and resource costs of leakage in water distribution systems: A shadow price approach.

Water scarcity is one of the main problems faced by many regions in the XXIst century. In this context, the need to reduce leakages from water distribution systems has gained almost universal acceptance. The concept of sustainable economic level of leakage (SELL) has been proposed to internalize the environmental and resource costs within economic level of leakage calculations. However, because these costs are not set by the market, they have not often been calculated. In this paper, the directional-distance function was used to estimate the shadow price of leakages as a proxy of their environmental and resource costs. This is a pioneering approach to the economic valuation of leakage externalities. An empirical application was carried out for the main Chilean water companies. The estimated results indicated that for 2014, the average shadow price of leakages was approximately 32% of the price of the water delivered. Moreover, as a sensitivity analysis, the shadow prices of the leakages were calculated from the perspective of the water companies' managers and the regulator. The methodology and findings of this study are essential for supporting the decision process of reducing leakage, contributing to the improvement of economic, social and environmental efficiency and sustainability of urban water supplies.

Relación entre el tiempo de circulación extracorpórea y el pinzamiento aórtico con diferentes variables de evolución postquirúrgicas / Relationship between cardiopulmonary bypass time and aortic cross clamping time with different variables of post-surgical evolution

Resumen Justificación: La mayor cantidad de cirugías cardiacas realizadas a nivel mundial se efectúa con circulación extracorpórea y pinzamiento de la aorta, lo que conlleva una serie de alteraciones fisiopatológicas que deben ser reconocidas por el personal de salud que participa en la atención de estos pacientes. Objetivo: Describir el perfil y los factores de riesgo presentes en los pacientes sometidos a cirugía cardiaca con circulación extracorpórea, y analizar la existencia de una potencial relación entre el tiempo de circulación extracorpórea y el pinzamiento aórtico, con la aplicación de desfibrilaciones tras al pinzado de la aorta, la necesidad de soporte cardiovascular farmacológico, el comportamiento del nivel de lactato plasmático y la mortalidad. Métodos: Se desarrolló un estudio observacional y descriptivo con una muestra de 104 pacientes electivos, sometidos a intervención quirúrgica y circulación extracorpórea, en el Hospital México, desde octubre de 2016 a noviembre de 2017. Se caracterizó la población en estudio, se analizaron los factores de riesgo incluido el EuroSCORE I y II, el tiempo de circulación extracorpórea, el tiempo de pinzamiento aórtico, las desfibrilaciones posteriores al pinzamiento aórtico, e lactato inmediatamente postcirculación extracorpórea, y a las 2, 6, 24 h postquirúrgicas, el uso de soporte cardiovascular farmacológico en infusión continua posterior a la circulación extracorpórea y mortalidad a los 30 días. Resultados: La edad media fue 56,4 años, predominó el sexo masculino (69 %) y la hipertensión arterial fue el factor de riesgo más frecuente (76,07 %). Se registró un tiempo de pinzado aórtico menor a 100 min en 61 pacientes (58,65 %) y superior a ese tiempo en 43 pacientes (41,35 %). El EuroSCORE I promedio fue del 4,21 % (DE: 4,80), mientras que el EuroSCORE II fue del 2,37 % (DE: 2,41). El tiempo promedio de circulación extracorpórea fue de 129 minutos (DE: 36,88) y el de pinzado aórtico, de 94 minutos (DE:32,04). Hubo un pico de lactato a las 6 horas postquirúrgicas (5,13 mmol/L, DE:2,89); un 8,65 % de los pacientes fueron desfibrilados después del retiro de la pinza en la aorta; se utilizó soporte cardiovascular en el 16,35 % y la mortalidad quirúrgica fue del 1,92 %. Conclusiones: En el estudio, el tiempo de circulación extracorpórea y el pinzado aórtico junto con el uso de inotrópicos, vasoconstrictores, hiperlactatemia y mortalidad quirúrgica, no alcanzó una relación significativa.

Abstract Justification: Currently, the largest number of cardiac surgeries performed worldwide are performed with cardiopulmonary bypass and aortic cross clamp, which leads to a series of pathophysiological alterations that are important for health personnel involved in the care of these patients. Objective: To describe the profile and risk factors present in patients undergoing cardiac surgery with cardiopulmonary bypass and the existence of a potential relationship between the cardiopulmonary bypass time and aortic cross clamping time, with the use of post clamp defibrillations, pharmacological cardiovascular support, plasma lactate behavior and mortality. Methods: An observational and descriptive study was carried out with a sample of 104 elective patients, undergoing surgical intervention and cardiopulmonary bypass at Hospital México, from October 2016 to November 2017. The study population was characterized, risk factors were analyzed including EuroSCORE I and II, CPB time, aortic cross clamping time, post-aortic clamping defibrillation, lactate immediately after extracorporeal circulation and at 2, 6, 24 hours postoperatively, use of pharmacological cardiovascular support in continuous infusion after extracorporeal circulation and mortality at 30 days. Results: The mean age was 56.4 years, the male sex predominated (69%) and arterial hypertension was the most frequent risk factor (76.07%). Aortic cross clamp time of less than 100 min was recorded in 61 patients (58.65%) and greater than that time in 43 patients (41.35%). The average EuroSCORE I was 4.21% (SD: 4.80), while the EuroSCORE II was 2.37% (SD: 2.41). The average cardiopulmonary bypass time was 129 minutes (SD: 36.88) and aortic cross clamp time was 94 minutes (SD: 32.04). There was a lactate peak at 6 postoperative hours (5.13 mmol/L, SD: 2.89); 8.65% of patients were defibrillated after removal the clamp in the aorta; pharmacological cardiovascular support was used in 16.35% and surgical mortality was 1.92%. Conclusions: In this study, cardiopulmonary bypass time and aortic cross clamp time together with the use of inotropics, vasoconstrictors, hyperlactatemia and surgical mortality did not reach a significant relationship.

Dengue y Bradicardia: caracterización clínica y evolución

Introducción: Las alteraciones de la conducción cardiaca y bradicardia, están descriptos en el Dengue, aunque su fisiopatología no es del todo clara. Objetivo: Describir las características clínicas y evolución de los pacientes con dengue y bradicardia. Metodología: estudio observacional, descriptivo, longitudinalde seguimiento de una cohorte. Fueron incluidos pacientes de 1 mes a 18 años ingresados en el Servicio de Urgencias del Hospital General Pediátrico Niños de Acosta Ñu, con diagnóstico de dengue, que presentaron bradicardia y que hayan tenido seguimiento hasta la desaparición del síntoma. Variables edad, sexo, clasificación del dengue, resultado del electrocardiograma (ECG), radiografía de tórax, inicio de bradicardia, frecuencia cardiaca al egreso, duración de la bradicardia en el seguimiento y días de hospitalización. Los datos fueron analizados en SPSSv 21, utilizando la estadística descriptiva. El protocolo fue aprobado por el Comité de ética. Resultados: En el periodo de estudio se hospitalizaron 310 pacientes con Dengue. El 6,4% (20/310) presentó bradicardia. La edad media fue de 12,7±2,8 años, con predominio del sexo masculino. Algunos pacientes ya tenían bradicardia en el momento del ingreso (9/20), mientras que otros lo presentaron en el curso de la hospitalización (11/20). Hubo un caso de bloqueo AV y los demás presentaron bradicardia sinusal (19/29). La bradicardia persistió al alta en la mayoría de los pacientes (18/20) y se resolvió durante la primera semana de seguimiento. El promedio de días de hospitalización fue 7,1±1,9. Conclusión: La frecuencia de bradicardia fue del 6,4%. La mayoría de los pacientes tenía el diagnóstico de Dengue Grave. Un alto porcentaje continuaba con bradicardia al momento del alta sin manifestaciones clínicas de dengue. En la mayoría de los pacientes se presentó durante la hospitalización y se normalizó durante el seguimiento al alta.

Introduction: Alterations in cardiac conduction and bradycardia are described in Dengue, although its pathophysiology is not entirely clear. Objective: To describe the clinical characteristics and course of patients with dengue and bradycardia. Methodology: This was an observational, descriptive and longitudinal cohort study. We enrolled patients from 1 month to 18 years of age who were admitted to the Emergency Department of the Acosta Ñu Children's General Hospital with a diagnosis of dengue, who presented bradycardia and who had follow-up until the disappearance of the symptom. The variables were age, sex, dengue classification, electrocardiogram (ECG) results, chest x-ray, onset of bradycardia, heart rate at discharge, duration of bradycardia during follow-up and days of hospitalization. Data were analyzed in SPSSv 21, using descriptive statistics. The protocol was approved by the Hospital Ethics Committee. Results: During the study period, 310 patients with Dengue were hospitalized. 6.4% (20/310) had bradycardia. The average age was 12.7 ± 2.8 years, with a predominance of males. Some patients already had bradycardia at the time of admission (9/20), while others developed it during hospitalization (11/20). There was one case of AV block and the others presented sinus bradycardia (19/29). Bradycardia persisted at discharge in most patients (18/20) and resolved during the first week of follow-up. The average number of hospitalization days was 7.1 ± 1.9. Conclusions: The frequency of bradycardia was 6.4%. The majority of patients had a diagnosis of severe dengue. A high percentage of patients continued to have bradycardia at discharge with no other clinical manifestations of dengue. In the majority of patients, bradycardia presented during hospitalization and normalized at their discharge follow-up.

Selenium supplementation modulates zinc levels and antioxidant values in blood and tissues of diabetic rats fed zinc-deficient diet.

Diabetes mellitus is associated to a reduction of antioxidant defenses that leads to oxidative stress and complications in diabetic individuals. The present study was undertaken to investigate the effect of selenium on blood biochemical parameters, antioxidant enzyme activities, and tissue zinc levels in alloxan-induced diabetic rats fed a zinc-deficient diet. The rats were divided into two groups; the first group was fed a zinc-sufficient diet, while the second group was fed a zinc-deficient diet. Half of each group was treated orally with 0.5 mg/kg sodium selenite. Tissue and blood samples were taken from all animals after 28 days of treatment. At the end of the experiment, the body weight gain and food intake of the zinc-deficient diabetic animals were lower than that of zinc-adequate diabetic animals. Inadequate dietary zinc intake increased glucose, lipids, triglycerides, urea, and liver lipid peroxidation levels. In contrast, serum protein, reduced glutathione, plasma zinc and tissue levels were decreased. A zinc-deficient diet led also to an increase in serum glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, and liver glutathione-S-transferase and to a decrease in serum alkaline phosphatase activity and glutathione peroxidase. Selenium treatment ameliorated all the values approximately to their normal levels. In conclusion, selenium supplementation presumably acting as an antioxidant led to an improvement of insulin activity, significantly reducing the severity of zinc deficiency in diabetes.

Vitamin D supplementation modulates blood and tissue zinc, liver glutathione and blood biochemical parameters in diabetic rats on a zinc-deficient diet.

Previous studies suggest a protective effect of vitamin D3 on zinc deficiency-induced insulin secretion and on pancreas ß-cell function. The aim of this study was to investigate the effect of vitamin D on blood biochemical parameters, tissue zinc and liver glutathione in diabetic rats fed a zinc-deficient diet. For that purpose, Alloxan-induced diabetic rats were divided into four groups. The first group was fed a zinc-sufficient diet while the second group was fed a zinc-deficient diet. The third and fourth groups received zinc-sufficient or zinc-deficient diets plus oral vitamin D3 for 27 days. At the end of the experiment, blood, femur, pancreas, kidney and liver samples were taken from all rats. The serum, femur, pancreas, kidney and liver zinc concentrations, liver glutathione, serum alkaline phosphatase activity, daily body weight gain and food intake were lower in the zinc-deficient rats in comparison with those receiving adequate amounts of zinc. These values were increased in the zinc-deficient group that was supplemented with vitamin D3. The serum total cholesterol, triglycerides, total protein, urea, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and blood glucose values were higher in rats fed a zinc adequate diet, but their concentrations were decreased by vitamin D3 supplementation. The serum total protein levels were not changed by zinc deficiency and vitamin D3 supplementation. These results suggest that vitamin D3 modulates tissue zinc, liver glutathione and blood biochemical values in diabetic rats fed a zinc-deficient diet.