Occupational Lead Exposure Ototoxicity Evaluated With Distortion-Product Otoacoustic Emissions.

OBJECTIVES: To evaluate the extent of hearing loss among pottery workers in Mexico exposed to lead. DESIGN: The authors conducted a cross-sectional study including 315 adult pottery workers. Auditory function was evaluated by air conduction pure-tone audiometry (pure-tone average) and distortion-product otoacoustic emission (DPOAE) levels (amplitude and signal-to-noise ratio). Lead exposure was assessed with a single blood sample test and classified as low, medium, and high according to blood lead tertiles. Logistic regression models were calculated for the association between blood lead levels, pure-tone average, and DPOAE records. RESULTS: Median (25th-75th) blood lead levels were 14 µg/dL (7.5-22.6 µg/dL). The audiometric pattern and DPOAE records were similar across blood lead levels groups in all frequencies, and no statistically significant differences were found. Adjusted logistic regression models showed no increase in the odds for hearing thresholds >25 dB (HL) and DPOAE absence associated with blood lead levels, and no dose-response pattern was observed ( p > 0.05). CONCLUSIONS: Given the results from this cross-sectional study, no association was found between blood lead levels and hearing loss assessed with DPOAE. Future longitudinal work should consider chronic lead exposure estimates among underrepresented populations, which can potentially inform safer work practices to minimize the risk of ototoxicity.

Relationship between urinary biomarkers of early kidney damage and exposure to inorganic toxins in a pediatric population of Apizaco, Tlaxcala, Mexico.

BACKGROUND: In recent years, chronic kidney disease has increased in the pediatric population and has been related to environmental factors. In the diagnosis of kidney damage, in addition to the traditional parameters, early kidney damage biomarkers, such as kidney injury molecule 1, cystatin C, and osteopontin, among others, have been implemented as predictors of early pathological processes. OBJECTIVE: This study aimed to evaluate the relationship between exposure to environmental pollutants and early kidney damage biomarkers. METHODS: A cross-sectional pilot study was conducted in February 2016 and involved 115 apparently healthy children aged 6-15 residing in Apizaco, Tlaxcala. Participant selection was carried out randomly from among 16,472 children from the municipality of Apizaco. A socio-demographic questionnaire included  age, sex, education, duration of residence in the area, occupation, water consumption and dietary habits, pathological history, and some non-specific symptoms. Physical examination included blood pressure, weight, and height. The urine concentrations of urinary aluminum, total arsenic, boron, calcium, chromium, copper, mercury, potassium, sodium, magnesium, manganese, molybdenum, lead, selenium, silicon, thallium, vanadium, uranium, and zinc, were measured. Four of the 115 participants selected for the study were excluded due to an incomplete questionnaire or lack of a medical examination, leaving a final sample population of 111 participants. RESULTS: The results showed a mean estimated glomerular filtration rate of 89.1 ± 9.98 mL/min/1.73m2 and a mean albumin/creatinine ratio of 12.9 ± 16.7 mg/g urinary creatinine. We observed a positive and significant correlation between estimated glomerular filtration rate with fluoride, total arsenic and lead, and a correlation of albumin/creatinine ratio with fluoride, vanadium, and total arsenic. There was also a significant correlation between the early kidney damage biomarkers and fluoride, vanadium, and total arsenic, except for cystatin C. CONCLUSION: In conclusion, our results show that four urinary biomarkers: α1-microglobulin, cystatin C, kidney injury molecule 1, and neutrophil gelatinase-associated lipocalin are related to environmental exposure to urinary fluoride, vanadium, and total arsenic in our pediatric population.

Assessment of miR-103a-3p in leukocytes-No diagnostic benefit in combination with the blood-based biomarkers mesothelin and calretinin for malignant pleural mesothelioma diagnosis.

Malignant pleural mesothelioma (MPM) is a cancer associated with asbestos exposure and its diagnosis is challenging due to the moderate sensitivities of the available methods. In this regard, miR-103a-3p was considered to increase the sensitivity of established biomarkers to detect MPM. Its behavior and diagnostic value in the Mexican population has not been previously evaluated. In 108 confirmed MPM cases and 218 controls, almost all formerly exposed to asbestos, we quantified miR-103-3a-3p levels in leukocytes using quantitative Real-Time PCR, together with mesothelin and calretinin measured in plasma by ELISA. Sensitivity and specificity of miR-103-3a-3p alone and in combination with mesothelin and calretinin were determined. Bivariate analysis was performed using Mann-Whitney U test and Spearman correlation. Non-conditional logistic regression models were used to calculate the area under curve (AUC), sensitivity, and specificity for the combination of biomarkers. Mesothelin and calretinin levels were higher among cases, remaining as well among males and participants ≤60 years old (only mesothelin). Significant differences for miR-103a-3p were observed between male cases and controls, whereas significant differences between cases and controls for mesothelin and calretinin were observed in men and women. At 95.5% specificity the individual sensitivity of miR-103a-3p was 4.4% in men, whereas the sensitivity of mesothelin and calretinin was 72.2% and 80.9%, respectively. Positive correlations for miR-103a-3p were observed with age, environmental asbestos exposure, years with diabetes mellitus, and glucose levels, while negative correlations were observed with years of occupational asbestos exposure, creatinine, erythrocytes, direct bilirubin, and leukocytes. The addition of miR-103a-3p to mesothelin and calretinin did not increase the diagnostic performance for MPM diagnosis. However, miR-103a-3p levels were correlated with several characteristics in the Mexican population.

Neurotoxicidad en trabajadores petroquímicos con bajos índices de exposición a disolventes orgánicos.

OBJETIVO: Estimar el desempeño neuropsicológico y su asociación con la exposición a disolventes orgánicos (DO) en trabajadores petroquímicos en México. Material y méto-dos. Estudio transversal en 203 trabajadores: 102 expuestos a DO y 101 no expuestos. Se evaluó el desempeño neuropsi-cológico con Neurobehavioral Core Test Battery y la exposición a DO con la medición de metabolitos de exposición para tolueno, xilenos y benceno. RESULTADOS: Los trabajadores expuestos presentaron un peor desempeño en todas las pruebas (p<0.05), excepto en la prueba de Santa Ana. Esto se corroboró con modelos de regresión; los trabajadores expuestos a DO tuvieron un mayor número de errores y realizaron las pruebas en mayor tiempo (p<0.05), además de presentar mayores probabilidades de padecer síntomas de neurotoxicidad (OR: 2.93; IC95%: 0.96, 8.96). Conclusio-nes. La exposición ocupacional a disolventes orgánicos, aun a niveles permitidos por la normatividad mexicana vigente, se relacionó con un menor desempeño neuropsicológico.

Neurotoxicidad en trabajadores petroquímicos con bajos índices de exposición a disolventes orgánicos / Neurotoxicity among petrochemical workers with low exposure indexes to organic solvents

Resumen: Objetivo: Estimar el desempeño neuropsicológico y su asociación con la exposición a disolventes orgánicos (DO) en trabajadores petroquímicos en México. Material y métodos: Estudio transversal en 203 trabajadores: 102 expuestos a DO y 101 no expuestos. Se evaluó el desempeño neuropsicológico con Neurobehavioral Core Test Battery y la exposición a DO con la medición de metabolitos de exposición para tolueno, xilenos y benceno. Resultados: Los trabajadores expuestos presentaron un peor desempeño en todas las pruebas (p<0.05), excepto en la prueba de Santa Ana. Esto se corroboró con modelos de regresión; los trabajadores expuestos a DO tuvieron un mayor número de errores y realizaron las pruebas en mayor tiempo (p<0.05), además de presentar mayores probabilidades de padecer síntomas de neurotoxicidad (OR: 2.93; IC95%: 0.96, 8.96). Conclusiones: La exposición ocupacional a disolventes orgánicos, aun a niveles permitidos por la normatividad mexicana vigente, se relacionó con un menor desempeño neuropsicológico.

Abstract: Objective: To estimate the neuropsychological performance and its association with exposure to organic solvents (OS) among petrochemical workers in Mexico. Materials and methods: Cross-sectional study including 203 workers: 102 exposed to OS and 101 non-exposed. Neuropsychological performance was evaluated with Neurobehavioral Core Test Battery. Exposure to OS was evaluated with the metabolites from exposure to toluene, xylenes and benzene. Results: Exposed workers presented with a worse performance in all tests (p<0.05), except for Santa Ana test. This was corroborated with regression models; workers exposed to OS had a higher number of mistakes and performed the tests in longer time (p<0.05), together with having greater odds of neurotoxicity symptoms (OR: 2.93; 95%CI: 0.96, 8.96). Conclusions: Occupational exposure to organic solvents, even at levels allowed by current Mexican standards, was related to an impaired neuropsychological performance.

Association between lead source exposure and blood lead levels in some lead manufacturing countries: A systematic review and meta-analysis.

Lead is one of the 10 most toxic chemicals of greatest concern for its effects on public health. Predominantly, in undeveloped countries, high blood lead levels (BLLs) persist in the population. To develop intervention strategies that may reduce lead exposure in populations, it is a priority to know the sources of lead pollution. The objective of this critical review and meta-analysis is to assess whether there is an association between different sources of lead exposure and the mean difference in blood lead levels in people exposed. To identify the major lead source exposure, a statistical analysis was performed on selection studies. This investigation reveals the limited information available on the sources of lead in Mexico and other lead producer countries, such as Croatia, Ecuador, Brazil, South Korea, India, Nigeria, Turkey, and China. Meta-analysis could be performed only in battery, smelting mining, and glazed ceramic workers. Battery manufacturing workers have the highest mean difference level of lead in their blood worldwide. Mexico has the second highest mean difference BLL in battery workers in the world. An interesting difference between the mean difference in BLL in mining workers from uncontrolled industry (-39.38) and controlled industry (-5.68) was found. This difference highlighted the success of applying strict control of lead sources and community education to reduce BLL and its potential harmful effects on human health and the environment. Children living near mining sites have the highest mean difference BLL (-11.1). This analysis may aid in assessing the source of lead exposure associated with a range of BLLs in people. Furthermore, this review highlights several social and cultural patterns associated with lead exposure and lead levels in control populations. These results could help to develop international lead regulations and appropriate public health guidelines to protect people around the world.

Audiometric findings of printing press workers exposed to noise and organic solvents.

OBJECTIVE: To determine if exposure to organic solvents and noise is associated with audiometric results among workers from a printing press in Mexico City. DESIGN: Cross-sectional study. STUDY SAMPLE: One hundred and seventy-six male workers at a printing press in Mexico City exposed to noise and organic solvents, including xylene, and 103 non-exposed male workers as reference group. Hearing thresholds were assessed with pure-tone audiometry. RESULTS: Poorer hearing thresholds were observed among printing workers than non-exposed controls, particularly among groups with over 5 years of exposure. Hearing thresholds differences were observed in the frequencies above 500 Hz, especially in 4000 Hz in all exposure groups compared to the reference. Adjusted models for age and previous exposure to noise and organic solvents showed worse hearing thresholds as years of seniority increased -ß coefficients (95% CI): ≤5 years: 3.06 dB (0.01, 6.10); >5-10 years: 4.51 dB (1.13, 7.89); >10 years: 4.58 dB (1.20, 7.96). Further analyses showed no interaction between noise and organic solvents on hearing thresholds, considering both current and previous occupational exposures. CONCLUSION: Exposure to noise levels that were below recommended exposure limits and organic solvents were associated with poorer hearing thresholds than those observed among non-exposed study participants. This suggests that workers exposed to solvents should be included in hearing conservation programmes, even when noise exposures are below 85 dB. If only noise levels were taken into consideration in the risk assessment of this worker population, the risk of hearing effects could have been overlooked.

Neuropsychological effects among workers exposed to organic solvents.

OBJECTIVE: To assess neuropsychological performance among workers at a paint factory in Mexico City. MATERIALS AND METHODS: During 2004 and 2005 we assessed the neuropsychological performance of 208 workers who were exposed to organic solvents at a paint factory, mainly toluene and xylene. We categorized workers into low and high exposure groups using a cumulative index for toluene, based on times spent in different tasks. We evaluated cognitive and motor functions with 13 neuropsychological tests. RESULTS: We found lower attention, longer time to complete the test ß=5.5 (R2=12.3%), and a lower score in the motor-cognitive test ß=-15.7 (R2=19.5%) in the high exposure group through multiple linear regression model analysis, with adjustment for age and education. CONCLUSIONS: Our results are similar to the ones reported in the literature, but the effects are less severe, probably due to lower exposure to organic solvents.

OBJETIVO: Evaluar el desempeño neuropsicológico de los trabajadores de una fábrica de pintura en la Ciudad de México. MATERIAL Y MÉTODOS: Se evaluó el desempeño neuropsicológico de 208 trabajadores expuestos a disolventes orgánicos, principalmente tolueno y xileno, en una fábrica de pintura en la Ciudad de México durante 2004 y 2005. Se categorizaron en grupos de baja y alta exposición con un índice acumulado de tolueno con base en el tiempo empleado por actividad. Se evaluaron funciones motoras y cognitivas con 13 pruebas neuropsicológicas. RESULTADOS: Se registró un tiempo más largo para completar la prueba ß=5.5 (R2=12.3%) y una puntuación baja en la prueba motor-cognitiva de ß=- 15.7 (R2=19.5%) en el grupo de alta exposición en los modelos de regresión lineal múltiple, ajustados por confusores. CONCLUSIONES: Los presentes resultados son similares a los reportados en la literatura, aunque los efectos son menos graves, probablemente debido a la baja exposición.

Neuropsychological effects among workers exposed to organic solvents / Efectos neuropsicológicos en trabajadores expuestos a disolventes orgánicos

Abstract: Objective: To assess neuropsychological performance among workers at a paint factory in Mexico City. Materials and methods: During 2004 and 2005 we assessed the neuropsychological performance of 208 workers who were exposed to organic solvents at a paint factory, mainly toluene and xylene. We categorized workers into low and high exposure groups using a cumulative index for toluene, based on times spent in different tasks. We evaluated cognitive and motor functions with 13 neuropsychological tests. Results: We found lower attention, longer time to complete the test β=5.5 (R2=12.3%), and a lower score in the motor-cognitive test β=-15.7 (R2=19.5%) in the high exposure group through multiple linear regression model analysis, with adjustment for age and education. Conclusion: Our results are similar to the ones reported in the literature, but the effects are less severe, probably due to lower exposure to organic solvents.

Resumen: Objetivo: Evaluar el desempeño neuropsicológico de los trabajadores de una fábrica de pintura en la Ciudad de México. Material y métodos: Se evaluó el desempeño neuropsicológico de 208 trabajadores expuestos a disolventes orgánicos, principalmente tolueno y xileno, en una fábrica de pintura en la Ciudad de México durante 2004 y 2005. Se categorizaron en grupos de baja y alta exposición con un índice acumulado de tolueno con base en el tiempo empleado por actividad. Se evaluaron funciones motoras y cognitivas con 13 pruebas neuropsicológicas. Resultados: Se registró un tiempo más largo para completar la prueba β=5.5 (R2=12.3%) y una puntuación baja en la prueba motor-cognitiva de β=-15.7 (R2=19.5%) en el grupo de alta exposición en los modelos de regresión lineal múltiple, ajustados por confusores. Conclusión: Los presentes resultados son similares a los reportados en la literatura, aunque los efectos son menos graves, probablemente debido a la baja exposición.

Chronic Kidney Disease in Children Aged 6-15 Years and Associated Risk Factors in Apizaco, Tlaxcala, Mexico, a Pilot Study.

INTRODUCTION: Tlaxcala, a small state in central Mexico, has the highest prevalence of chronic kidney disease (CKD) deaths in population aged 5-14 in Mexico, most of them with unknown etiology. OBJECTIVE: To determine the prevalence of CKD in apparently healthy pediatric population in Apizaco, Tlaxcala. METHODS: A cross-sectional pilot study was carried out in children deemed as healthy; subjects with previous diagnosis of CKD were excluded. Informed consent was obtained in all cases. A physical examination was performed, a questionnaire was applied. Blood and urine samples were obtained for serum creatinine, urinalysis, and microalbumin/creatinine ratio. A second and third evaluation was performed after 6 and 18 months in those found with urinary anomalies/CKD to confirm the diagnosis. RESULTS: One hundred and nine subjects completed physical examination, which are the biological samples. Median age was 12 years. CKD stage 2 was confirmed in 5 subjects in the sixth month confirmation visit (4.6%). One patient accepted renal biopsy and Alport Syndrome was found. In a robust multivariate analysis, the risk factors related to reduction in the glomerular filtration rate were males -5.15 mL/min/1.73 m2 (p = 0.002), older participants as by -1.58 mL/min/1.73 m2 per year (p < 0.0001), and among participants living close to a river -3.76 mL/min/1.73 m2 (p = 0.033). DISCUSSION/CONCLUSION: The prevalence of CKD in the population studied in Apizaco Tlaxcala was confirmed in 4.6 cases per 100 inhabitants between 6 and 15 years. Males, older age, and living close to a river were the risk predictive factors. More studies are needed to determine the causes of the high CKD prevalence in this population.

Mesothelin, Calretinin, and Megakaryocyte Potentiating Factor as Biomarkers of Malignant Pleural Mesothelioma.

PURPOSE: Malignant pleural mesothelioma (MPM) is a highly lethal cancer caused by exposure to asbestos. Currently, the diagnosis is a challenge, carried out by means of invasive methods of limited sensitivity. This is a case-control study to evaluate the individual and combined performance of minimally invasive biomarkers for the diagnosis of MPM. METHOD: A study of 166 incident cases of MPM and 378 population controls of Mestizo-Mexican ethnicity was conducted. Mesothelin, calretinin, and megakaryocyte potentiating factor (MPF) were quantified in plasma by ELISA. The samples were collected from 2011 to 2016. RESULTS: Based on ROC analysis and a preset specificity of 95%, the combination of the three biomarkers reached an AUC of 0.944 and a sensitivity of 82% in men. In women, an AUC of 0.937 and a sensitivity of 87% were reached. In nonconditional logistic regression models, the adjusted ORs in men were 7.92 (95% CI 3.02-20.78) for mesothelin, 20.44 (95% CI 8.90-46.94) for calretinin, and 4.37 (95% CI 1.60-11.94) for MPF. The ORs for women were 28.89 (95% CI 7.32-113.99), 17.89 (95% CI 3.93-81.49), and 2.77 (95% CI 0.47-16.21), respectively. CONCLUSIONS: To our knowledge, this is the first study evaluating a combination of mesothelin, calretinin, and MPF, and demonstrating a sex effect for calretinin. The biomarker panel showed a good performance in a Mestizo-Mexican population, with high sensitivity and specificity for the diagnosis of MPM.

Determination of reference ranges for coagulation tests in Mexican-mestizo population / Determinación de límites de referencia de pruebas de coagulación en población mestizo-mexicana

Background: It is necessary to establish biological parameters for each population. Objective: To establish reference values for prothrombin time (PT), activated partial thromboplastin time (PTT) and fibrinogen in healthy population and to determine intra- and inter-assay concordance. Methods: Cross-sectional study that included 204 women and 202 men from the Blood Donor service. Coagulation tests were carried out in order to obtain reference ranges. All procedures were made according to the Clinical & Laboratory Standards Institute guidelines. Results: Mean PT, PTT and fibrinogen were 14.1 s, 28.8 s and 381 mg/dL in men, and 15.1 s, 29.0 s and 381 mg/dL in women. The proposed PT, PTT and fibrinogen reference ranges for men were 12.7 to 16.3 s, 24.2 to 36.3 s and 239 to 276 mg/dL, respectively; for women, 12.7 to 16.6 s, 23.5 to 35.4 s and 276 to 598 mg/dL. The latter was statistically significant (p ≤ 0.001). Conclusions: Reference values for blood coagulation tests were determined. This is of great importance for fast medical diagnosis and treatment. The results from this study can be adopted by other clinic laboratories after appropriate validation procedures.

Introducción: Es necesario establecer valores de referencia biológicos para cada población. Objetivo: Establecer los límites de referencia de tiempo de protrombina (TP), tiempo parcial de tromboplastina (TTP) y fibrinógeno en población mestizo-mexicana sana, así como la correlación y la concordancia en la determinación de estas pruebas con los dos equipos utilizados. Métodos: Estudio transversal en 204 mujeres y 202 hombres que acudieron al servicio de donadores y se les determinó TP, TTP y fibrinógeno para obtener los límites de referencia. Los procedimientos se realizaron de acuerdo con las guías del Instituto de Estándares de Laboratorio y Clínicos (CLSI C28-A3). Resultados: La media de TP, TTP y fibrinógeno en hombres fue de 14.1 s, 28.8 s y 381 mg/dL, y en mujeres de 15.1 s, 29.0 s y 381 mg/dL, respectivamente. Los límites de referencia para hombres en TP, TTP y fibrinógeno fueron de 12.7 a 16.3 s, de 24.2 a 36.3 s y de 239 a 276 mg/dL; para mujeres de 12.7 a 16.6 s, de 23.5 a 35.4 s y de 276 a 598 mg/dL, respectivamente. Este último fue estadísticamente significativo (p ≤ 0.001). Conclusiones: Se determinaron los límites de referencia para las pruebas de coagulación. Los resultados obtenidos en este estudio pueden ser adoptados por otros laboratorios clínicos, después de su apropiada validación.

Biomarkers for Predicting Malignant Pleural Mesothelioma in a Mexican Population.

Background: Diagnosis of malignant pleural mesothelioma (MPM) remains a challenge, especially when resources in pathology are limited. The study aimed to evaluate cost-effective tumor markers to predict the probability of MPM in plasma samples in order to accelerate the diagnostic workup of the tissue of potential cases. Methods: We conducted a case-control study stratified by gender, which included 75 incident cases with MPM from three Mexican hospitals and 240 controls frequency-matched by age and year of blood drawing. Plasma samples were obtained to determine mesothelin, calretinin, and thrombomodulin using enzyme-linked immunosorbent assays (ELISAs). We estimated the performance of the markers based on the area under the curve (AUC) and predicted the probability of an MPM diagnosis of a potential case based on the marker concentrations. Results: Mesothelin and calretinin, but not thrombomodulin were significant predictors of a diagnosis of MPM with AUCs of 0.90 (95% CI: 0.85-0.95), 0.88 (95% CI: 0.82-0.94), and 0.51 (95% CI: 0.41-0.61) in males, respectively. For MPM diagnosis in men we estimated a true positive rate of 0.79 and a false positive rate of 0.11 for mesothelin. The corresponding figures for calretinin were 0.81 and 0.18, and for both markers combined 0.84 and 0.11, respectively. Conclusions: We developed prediction models based on plasma concentrations of mesothelin and calretinin to estimate the probability of an MPM diagnosis. Both markers showed a good performance and could be used to accelerate the diagnostic workup of tissue samples in Mexico.

[Chronic kidney disease in Mexico and its relation with heavy metals]. / Enfermedad renal crónica en México y su relación con los metales pesados.

Chronic kidney disease (CKD) is a public health problem in Mexico, causing 25% of deaths related to diabetes mellitus (DM) and 28% related to hypertensive heart disease. In 2008 CKD reached the highest incidence of end-stage renal disease in the world. Diabetes mellitus is the main risk factor associated with CKD in Mexican population; however, heavy metals such as lead, arsenic, cadmium and mercury have been associated to nephropathies. In Mexico there are still high levels of these compounds in occupational and environmental settings; therefore, chronic exposures to these metals persist. In this review we approach to the main mechanisms of action of these metals in the body and its renal effects, as well as information about the sources of exposure to these chemical risks, the relationship between exposure to heavy metals and CKD, coupled with the economic and social consequences of this disease.

La enfermedad renal crónica (ERC) constituye un problema de salud pública en México, pues ocasiona el 25% de las muertes en pacientes con diabetes mellitus (DM) y 28% de las muertes relacionadas con cardiopatía hipertensiva. En 2008 la ERC alcanzó la tasa de incidencia más alta de enfermedad renal terminal en el mundo. La DM es el principal factor de riesgo asociado a la ERC en la población mexicana; sin embargo, los metales pesados como el plomo, el arsénico, el cadmio y el mercurio se han relacionado con las nefropatías. En México aún persisten niveles elevados de estos compuestos en diversos trabajos y en el ambiente, lo que condiciona una exposición crónica en la población. En esta revisión se describen los principales mecanismos de acción de estos metales en el organismo, así como sus efectos a nivel renal, además de información acerca de las fuentes de exposición a estos riesgos químicos, la relación entre la exposición a metales pesados y ERC, y, por último, las consecuencias económicas y sociales de esta enfermedad.

[Intelligence quotient loss in Mexican pottery artisan's children]. / Pérdida de coeficiente intelectual en hijos de alfareros mexicanos.

BACKGROUND: In Mexico, artisans frequently use lead oxide or greta in order to produce utensils, which are destined to preparation and storage of food and drinks. Additionally, the risk of lead poisoning of artisans and their families is greater than in general population, and within these families, children are the most susceptible to lead poisoning. The aim of this study was to estimate IQ loss in Mexican children from potter families exposed to lead. METHODS: Lead concentrations in soil were determined in 19 potter's homes that functioned as pottery workshops in seven Mexican states between 2009 and 2012. This information was used to estimate blood lead levels through the integrated exposure uptake biokinetic (IEUBK) model. The loss of IQ points was then estimated according to the Lanphear and Schwartz models. RESULTS: The mean lead concentration found in the workshops' soil was 1098.4 ppm. Blood lead levels estimated in children under 8 years old were 26.4 µg/dL and the loss of IQ points comprised from 7.13 to 8.84 points depending on the model. CONCLUSIONS: It is possible that 11 children from families of artisans in Mexico may be losing between 7.13 to 8.84 IQ points, due to lead exposure in their houses-workshops. This loss in IQ points could have important health, economic and social impacts.

Introducción: en México, los alfareros continúan usando frecuentemente el óxido de plomo o greta para producir utensilios, los cuales se destinan a la preparación y almacenamiento de alimentos y bebidas. Adicionalmente, el riesgo de intoxicación por plomo de los alfareros y sus familias es mayor que en la población general, y en tales familias, los niños son los más susceptibles a la intoxicación por plomo. El objetivo del estudio fue estimar la pérdida de puntos de coeficiente intelectual (CI) en hijos de alfareros mexicanos expuestos al plomo. Métodos: durante el periodo de 2009 a 2012 se determinaron las concentraciones de plomo en suelo de 19 casas-talleres de alfareros en siete estados mexicanos. Esta información se utilizó para estimar el nivel de plomo en sangre, por medio del modelo biocinético integrado de absorción por exposición (IEUBK, por sus siglas en inglés). Posteriormente, se calcularon los puntos perdidos de CI según los modelos de Schwartz y Lanphear. Resultados: la concentración promedio de plomo en suelo fue de 1098.4 ppm. Se estimó un nivel de plomo en sangre de 26.4 µg/dL para menores de 8 años. La pérdida de puntos de CI estimada fue 7.13 y 8.84, según el modelo utilizado. Conclusión: es posible que al menos 11 niños de familias alfareras mexicanas estén perdiendo entre 7.13 y 8.84 puntos de CI, debido a la exposición al plomo en sus casas-talleres, lo que supone importantes impactos económicos, sociales y de salud.

[Update on epidemiology, pathophysiology, diagnosis and treatment of malignant pleural mesothelioma]. / Actualización sobre la epidemiología, fisiopatología, diagnóstico y tratamiento del mesotelioma maligno pleural.

Malignant pleural mesothelioma is an occupational tumor caused by asbestos exposure. In Mexico, as asbestos usage is not prohibited, an increase in the number of cases is expected. Asbestos exposure is ubiquitous due to the great amount of products in which it is present. Its carcinogenicity is caused as the inhaled asbestos fibers cannot be eliminated by macrophages and, thus, they travel to the pleura through lymphatic pathways, producing a persistent inflammatory response. Diagnosis approach includes occupational history, along with clinical signs and symptoms, and paraclinical studies, such as pleural fluid cytology, chest x-rays, computed tomography, magnetic resonance imaging, and biopsy with immunohistochemistry. The main differential diagnosis is lung adenocarcinoma. Regarding the treatment of this tumor, it mainly comprises palliative care, even though chemotherapy, radiotherapy, and, in selected cases, surgical treatments have been used. There is an urgent need for general physicians and specialists to identify asbestos exposure, in order to make a timely diagnosis. Research is necessary to develop screening and prompt diagnostic tools, along with an epidemiological surveillance program for the workers and the general population exposed to asbestos.

El mesotelioma maligno pleural es un tumor ocupacional ocasionado por la exposición a cualquier tipo de fibra de asbesto. Y dado que en México el uso del asbesto no está prohibido, se espera que la incidencia de este tumor siga aumentando. La exposición al asbesto es ubicua, debido a la gran diversidad de productos en los que se encuentra. Su carcinogenicidad está dada porque las fibras de asbesto inhaladas no pueden ser eliminadas por los macrófagos y viajan hacia la pleura por vía linfática, donde producen una reacción inflamatoria persistente. Para su diagnóstico se precisa de una historia clínica laboral, además de que hay que orientarse con base en el cuadro clínico y los estudios paraclínicos, como la citología de líquido pleural, radiografía de tórax, tomografía axial computarizada, resonancia magnética y biopsia con inmunohistoquímica. El principal diagnóstico diferencial es el adenocarcinoma de pulmón. El tratamiento es principalmente paliativo, aunque se ha utilizado quimioterapia, radioterapia y, en seleccionados casos, cirugía. Para lograr un diagnóstico oportuno y certero es de vital importancia identificar las exposiciones al asbesto. Por otra parte, es necesaria la investigación para desarrollar pruebas de diagnóstico temprano y tamizaje, además de un programa de vigilancia epidemiológica para los trabajadores y la población general expuesta al asbesto.

[Brainstem auditory evoked potentials latencies, by age and sex, among Mexican adult population]. / Latencias de los potenciales evocados auditivos del tallo cerebral, por edad y sexo, en población adulta mexicana.

BACKGROUND: Brainstem auditory evoked potentials (BAEP) evaluate the auditory pathway, and are a complementary test for tone audiometry in evaluating auditory diseases. The aim of the study was to determine BAEP mean latencies of waves and intervals, among healthy adults. METHODS: Cross-sectional study, comprising 196 subjects, aged 16 to 65 years, without auditory diseases, to whom family and personal history were asked, physical examination and laboratory studies were made, as well as tonal audiometry, impedanciometry and BAEP. RESULTS: A total of 107 men and 89 women were studied. The mean latency periods of waves I, III and V, and intervals I-III, III-V and I-V from both ears were similar. An increase in the latency periods for each age category was observed. Latency periods were significantly shorter in women compared to men. The predictors that increased the latency periods in the multiple linear regression models for waves and intervals were male gender and age ≥45 years. CONCLUSIONS: Age and sex were the variables that showed more statistical power to explain the latencies' differences.

Introducción: los potenciales evocados auditivos del tallo cerebral (PEATC) evalúan la vía auditiva central y son una herramienta complementaria de la audiometría tonal para analizar enfermedades auditivas. El objetivo de este estudio fue determinar el tiempo promedio de las latencias de las ondas y los intervalos de los potenciales evocados auditivos en adultos sanos. Métodos: estudio transversal que contó con 196 participantes, de 16 a 65 años de edad normo-oyentes, a quienes se investigaron antecedentes familiares y personales patológicos, se realizó exploración física y se obtuvieron estudios de laboratorio, audiometría tonal e impedanciometría normales, y potenciales evocados auditivos. Resultados: Se estudiaron 107 hombres y 89 mujeres. El promedio de las latencias de las ondas I, III y V e intervalos I-III, III-V y I-V de ambos oídos fueron similares. Los predictores que incrementaron el tiempo de latencia en los modelos de regresión lineal múltiple de las ondas e intervalos fueron el sexo masculino y la edad ≥ 45 años. Conclusiones: la edad y el sexo fueron las variables que mostraron mayor poder estadístico para explicar las diferencias de las latencias en este grupo de personas.

Blood lead determinants and the prevalence of neuropsychiatric symptoms in firearm users in Mexico.

OBJECTIVES: To identify blood lead predictors and the prevalence of neuropsychiatric symptoms in firearm users of public security in Mexico. MATERIAL AND METHODS: A cross-sectional study was performed on 65 males. We obtained socio-occupational data and determined venous blood lead (blood (B), lead (Pb) - BPb), as well as neuropsychiatric symptoms using the Q-16 questionnaire. A multiple linear regression model was constructed to assess determinants of BPb. RESULTS: The mean age in the study group was 34.8 years (standard deviation (SD) = 6.9, range: 21-60); the mean number of years spent in the company amounted to 14 years (SD = 8.5, range: 1-48). Twenty percent of the respondents (N = 13) used leaded glazed clay pottery (lead (Pb), glazed (G), and clay pottery (C) - PbGC) in the kitchen. During practice they fired a mean of 72 shots (SD = 60, range: 20-250), and during their whole duration of employment 5483 shots (SD = 8322.5, range: 200-50 000). The mean BPb was 7.6 µg/dl (SD = 6.8, range: 2.7-51.7). Two caretakers from the firing range had 29.6 µg/dl and 51.7 µg/dl BPb. The subjects who had shooting practice sessions ≥ 12 times a year reported a greater percentage of miscarriages in their partners (24% vs. 0%). Twelve percent of the respondents showed an increase in neuropsychiatric symptoms. The BPb multiple linear regression model explained R2 = 44.15%, as follows: those who had ≥ 12 practice sessions per year - ß = 0.5339 and those who used PbGC - ß = 0.3651. CONCLUSIONS: Using firearms and PbGC contributes to the increased BPb in the studied personnel. The determinants of BPb were: shooting practices >12 times a year and using PbGC. Blood lead concentrations reported in the study, despite being low, are a health risk, as evidenced by the prevalence of neuropsychiatric symptoms.

Alteraciones neuropsicológicas por exposición crónica a concentraciones bajas de monóxido de carbono en trabajadores de autopista de peaje de México / Neuropsychological alterations by chronic exposure to low concentrations of carbon monoxide in highway workers of Mexico

ANTECEDENTES: Trabajadores de la industria automovilística, estaciones de servicio, autopistas de peaje, estacionamientos y los que laboran en las calles, están en contacto crónico con bajas concentraciones de monóxido de carbono (CO) y, por lo tanto, en riesgo de sufrir alteraciones en los sistemas cardiovascular, hematológico y nervioso. OBJETIVO: Identificar la relación de las alteraciones neuropsicológicas con la exposición crónica a bajas concentraciones de CO, en trabajadores de autopistas de peaje. MÉTODO: Estudio transversal en 72 trabajadores de autopistas de peaje de la carretera México-Puebla; 60 cajeros y 12 encargados de turno. Se exploraron variables socio-demográficas, clínicas y ocupacionales, y se determinó hemoglobina (Hb), hematocrito (Htc) y carboxihemoglobina (COHb) en sangre. Se aplicaron pruebas neuropsicológicas (Carbon monoxide neuropsychological screening battery CONSB). Los encargados de turno conformaron el grupo menos expuesto y los cajeros el de mayor exposición a CO. RESULTADOS: En 49 trabajadores, Hb: 18.1±1.9 mg/dL y Htc: 55.3±8.7, sin diferencias significativas entre grupos (p = 0.82). Se observó menor desempeño en el grupo más expuesto, en el test de dígitos y símbolos (p = 0.012), senderos B (p = 0.002) y dígitos (p = 0.003). El test de construcción con bloques resultó limítrofe (p = 0.07). DISCUSIÓN Y CONCLUSIÓN: El grupo de mayor exposición al CO tuvo menor desempeño en percepción visual, codificación, percepción visomotora y memoria inmediata. Por ello, consideramos importante realizar vigilancia epidemiológica en los trabajadores, para intervenir en los casos con alteraciones en las pruebas. Asimismo, se debe evitar la percepción de que la exposición crónica al CO en estos trabajadores es inocua.

BACKGROUND: Workers of the automobile industry, service stations and those working in the streets, are in chronic contact to low concentrations of carbon monoxide and at risk to damage the cardiovascular, haematology and nervous systems. OBJECTIVE: Identify erythrocytosis and neuropsychological alterations in highway workers chronically exposed to low concentrations of CO. METHOD: Cross-sectional study that included 72 workers of the Mexico-Puebla Highway cabins (guards); 60 cashiers and 12 workers in charge of the shift, in which socio-demographic, clinical and occupational variables were explored; haemoglobin(Hb), hematocrit (Htc) and carboxyhemoglobin (COHb) was determined in their blood, and it was applied the Carbon monoxide neuropsychological screening battery (CONSB). The workers who are in charge of the full shift integrated the less exposed to CO group, while the cashiers would shape the greater exposure group. RESULTS: In 49 workers, Hb: 18.1±1.9 mg/dL and Htc: 55.3±8.7 without significant differences between groups (p=0.82). The greater alteration was identified in the exposed group in the test of digit symbol (p= 0.012), trail-making part B (p= 0.002), and digit span (p=0.003); the test of blocks design resulted borderline (p=0.07). DISCUSSION AND CONCLUSIÓN: The group with the highest exposure to CO had lower performance in visual perception, encoding, visual-motor perception and immediate memory. Therefore important to consider epidemiological surveillance workers to intervene in cases with abnormal tests. The perception of innocuousness of chronic exposure to CO in these workers must avoid.

[Historical and social perspective from the 64-65 Mexican medical movement]. / Perspectiva histórica y social del Movimiento Médico de 1964-1965 en México.

The Mexican Medical Movement from 1964-1965 constitutes an important event from the rising urban middle-class, besides it was the first time medical doctors claimed for fair working conditions. The background of this movement is the so-called Crisis of 1958, which included the Movements from the educators union, oil workers union, telegraph workers union and the railroad workers union. The conflict began because interns and residents from the "Hospital 20 de Noviembre" would not get a payment at the end of the year, so on November 26th, 1964, the movement started. The Asociación Mexicana de Médicos Residentes e Internos (AMMRI) was created and their demands were the following: 1) Full working site restitution without retaliations, 2) Legal examination of the scholarship-contract terms, in order to get annual, renewable and progressive contracts, and a fixed salary with the usual working-hours and characteristics of each institution, 3) To have preference to get an adscription at the hospital where the resident studied, 4) Active participation from the resident in the elaboration of the academic plans, and 5) Resolution of each hospital's problems. This movement had social impact for Mexico's contemporary life, nevertheless some of the demands are still unchanged among medical residents.

El movimiento médico mexicano de 1964-1965 constituyó parte del primer despertar de la clase media urbana, además de haber sido la primera vez que los médicos reclamaron condiciones de trabajo justas. Como antecedente se tiene la llamada crisis de 1958, la cual incluyó los movimientos: revolucionario del Magisterio, del Sindicato de Trabajadores Petroleros, de la Alianza de Telegrafistas, y del Sindicato de Trabajadores Ferrocarrileros de la República Mexicana. El comienzo del conflicto médico se debió a que los residentes e internos del Hospital 20 de Noviembre del hoy Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE) no recibieron su aguinaldo, por lo que el 26 de noviembre de 1964 inició el paro, a partir del cual se formó la Asociación Mexicana de Médicos Residentes e Internos (AMMRI), cuyas demandas fueron: 1) Restitución total en sus puestos, sin represalias, 2) Revisión legal y cambio de los términos del contrato-beca, en el sentido de lograr contratos de trabajo anuales, renovables y progresivos, con el horario y características acostumbrados en cada institución además de determinación de sueldos base, 3) Preferencia para ocupar plaza de médico adscrito a los residentes egresados de las propias instituciones, 4) Participación activa del residente en la elaboración de los planes de enseñanza, y 5) Resolución de los problemas de cada hospital. Este movimiento, aunque tuvo repercusiones sociales para la vida contemporánea en México, a 50 años de su inicio, algunas de las demandas siguen sin ser resueltas para los médicos residentes.