In El Salvador, chronic kidney disease had reached epidemic proportions towards the end of this century’s first decade. In 2011–2012, the Ministry of Health reported it was the leading cause of hospital deaths in men, the fifth in women, and the third overall in adult hospital fatalities. Farming was the most common occupation among men in dialysis (50.7%). By 2017, chronic kidney disease admissions had overwhelmed hospital capacity. In 2009, El Salvador’s Ministry of Health, Cuba’s Ministry of Public Health and PAHO launched a cooperative effort to comprehensively tackle the epidemic. The joint investigations revealed a total prevalence of chronic kidney disease in the adult population of farming communities higher than that reported internationally (18% vs.11%–14.8%), higher in men than in women (23.9% vs 13.9%) and higher in men who were farmers/farmworkers than in men who were not (31.3% vs. 14.8%). The disease was also detected in children. An association was found between chronic kidney disease and exposure to agrochemicals (OR 1.4–2.5). In 51.9% of all chronic kidney disease cases, traditional causes (diabetes, hypertension, glomerulopathies, obstructive nephropathies and cystic diseases) were ruled out and the existence of a particular form of chronic kidney disease of nontraditional etiology was confirmed (whose initial cases were reported as early as 2002). In the patients studied, functional alterations and histopathologic diagnosis confirmed a chronic tubulointerstitial nephritis; most presented with neurosensory hearing loss, altered tendon reflexes and tibial artery damage. The main results of this cooperation were the epidemiologic, physiopathologic, clinical and histopathologic characterization of chronic kidney disease of nontraditional etiology. This characterization facilitated case definition for the epidemic and led to the hypothesis of systemic toxicity from agrochemicals (e.g., paraquat, glyphosate), which particularly affect the kidneys and to which farmers/farmworkers (who may also become dehydrated in the fields) are most exposed. The research thus also laid the foundations for design of comprehensive intersectoral government actions to reduce cases and put an end to the epidemic. Chronic kidney disease; chronic renal failure; tubulointerstitial nephritis; epidemiology; histopathology; international cooperation; agrochemicals; environmental pollutants, noxae, and pesticides; occupational health; PAHO; El Salvador; Cuba

INTRODUCTION: For at least a decade, a chronic kidney disease unassociated with diabetes mellitus, hypertension or any of the more common traditional causes, has been reported in Salvadoran agricultural communities. OBJECTIVE: Characterize histopathology of chronic kidney disease of unknown etiology in patients from Salvadoran agricultural communities, describe renal damage associated with each disease stage, and assess associations between histopathological alterations and sociodemographic variables. METHODS: The study involved 46 patients of both sexes, aged ≥18 years. After clinical, laboratory and imaging examinations, kidney biopsies were performed and renal tissue assessed for interstitial fibrosis, tubular atrophy, interstitial inflammatory infiltration, sclerosis, increase in glomerular size and extraglomerular vascular lesions (according to the Banff 97 classification used for kidney transplant rejection). Special staining was done: Schiff periodic acid, Masson trichrome and methenamine silver. Immunofluorescence techniques were used to evaluate IgA, IgG, IgM, complement C1q and C3, fibrin, and kappa and lambda light chain deposits. RESULTS: The main findings were interstitial fibrosis and tubular atrophy with or without inflammatory monocyte infiltration. In addition, generalized sclerosis, increased glomerular size, collapse of some glomerular tufts, and lesions of extraglomerular blood vessels (such as intimal proliferation and thickening and vacuolization of the tunica media) were observed. Interstitial fibrosis and glomerulosclerosis were associated with male sex. Sugarcane workers showed more interstitial fibrosis and tubular atrophy and less glomerulomegaly than other occupational groups. CONCLUSION: The morphological pattern in all biopsies was one of chronic tubulointerstitial nephropathy with secondary glomerular and vascular damage, in different stages of evolution of chronic kidney disease, independent of age, sex or occupation.

Mantle cell lymphoma is an infrequent type of non-Hodgkin lymphoma with high relapse rates and poor prognosis. Lymphomas can induce kidney damage in several ways, including renal infiltration and the development of glomerulopathies. A case associated to the clinical onset of a mantle cell lymphoma with lymphocytic infiltration into the renal parenchyma and mesangiocapillary glomerulonephritis without cryoglobulinemia was presented. This is the first case report that describes this association which evidences the different types of renal lesions in no Hodgkin lymphoma and the value of renal histological study for the diagnosis and prognosis of onco-hematologic diseases with kidney damage.

El linfoma de células del manto es una forma infrecuente de linfoma no Hodgkin con alta frecuencia de recaídas y peor pronóstico. Los linfomas pueden inducir daño renal de diferentes modos, entre los que se encuentran la infiltración renal y el desarrollo de glomerulopatías. Se presentó un caso en el que se asocia el comienzo clínico de un linfoma de células del manto con infiltración parenquimatosa renal y glomerulonefritis mesangiocapilar sin crioglobulinemia. Este constituye el primer caso reportado con esta asociación y pone en evidencia las diferentes formas de afectación renal del linfoma no Hodgkin y el valor del estudio histológico renal, para el diagnóstico y el pronóstico de las enfermedades oncohematológicas con daño renal.

En los últimos años, los mercados de valores han adquirido una mayor importancia dentro de la economía; cada vez es mayor el número de personas interesadas en su funcionamiento y que centran su atención en el mercado de capitales. Las empresas especializadas se dirigen a las bolsas de valores a demandar fondos o a invertirlos; los inversionistas independientes también han acudido frecuentemente a buscar mejores rendimientos para sus inversiones. Por todo lo anterior, este estudio muestra la eficiencia aplicada a un caso de estudio sobre un grupo de activos del mercado bursátil, el cual tendrá especial interés para aquellas personas que desean invertir o estudiar empresas que cotizan en la Bolsa Mexicana de Valores. El presente artículo puede resultar de gran interés para personas que, con diferente formación, invierten en valores negociados en la bolsa, en específico en acciones de empresas que cotizan para el índice de Precios y Cotizaciones (IPC). Por ello, se detallan algunas definiciones importantes para el entendimiento del portafolio de inversión, además se describe la metodología utilizada para calcular los rendimientos del portafolio con el propósito de realizar inversiones óptimas en instrumentos de renta variable como las acciones, utilizando el procedimiento de Harry Markowitz con un enfoque estocástico.

In recent years, stock markets have become more important in the economy. The number of people interested in them and focusing their attention on the capital market is increasing. Specialized companies address the stock exchanges to demand or invest funds; independent investors also do so frequently, seeking better returns on their investments. Given the above, this study shows the efficiency applied to a case study of a group of assets in the stock market, which will be of particular interest to those who wish to invest in or study companies listed on the Mexican Stock Exchange. This article may be of great interest for those who, having different backgrounds, invest in securities traded on the stock market, specifically in shares of companies listed in the Index of Prices and Quotations (IPC). It explains some important definitions for the understanding of the investment portfolio, as well as the methodology used to calculate the returns of the portfolio in order to make optimal investments in equity instruments such as stocks, using the Harry Markowitz procedure with a stochastic approach.

Nos últimos anos, os mercados de valores têm adquirido mais importância na economia. Cada vez mais é maior o número de pessoas interessadas no seu desempenho e que focaliza a sua atenção no mercado de capitais. Empresas especializadas procuram bolsas de valores para demandar fundos ou para investir. Investidores independentes também têm vindo com frequência para buscar melhores rendimentos sobre os seus investimentos. Diante do exposto, este estudo mostra a eficiência aplicada a um caso de estudo de um grupo de ativos no mercado bolsista, que será de particular interesse para aqueles que desejam investir ou estudar companhias listadas na Bolsa Mexicana de Valores. Este artigo pode ser de grande interesse para pessoas com diferentes formações, que investem em valores negociados na bolsa, especialmente em ações de empresas listadas no índice de Preços e Cotações (IPC). Portanto, detalham-se algumas definições importantes para a compreensão da carteira de investimentos, e descreve-se a metodologia usada para calcular os rendimentos da carteira, a fim de fazer investimentos ótimos em instrumentos de rendas variáveis, tais como ações, utilizando o procedimento de Harry Markowitz com uma abordagem estocástica.