Prevalence and clinical-epidemiologic characteristics of a Mexican population with metabolic (dysfunction) associated fatty liver disease: An open population study.

INTRODUCTION AND AIMS: The risk factors for fatty liver disease are frequent in the Mexican population and the available studies appear to underestimate its prevalence. Our aims were to know the prevalence of metabolic (dysfunction) associated fatty liver disease (MAFLD) in an open population and determine the clinical and sociodemographic characteristics, nutritional status, physical activity level, and prevalence of metabolic syndrome, in the affected population. MATERIALS AND METHODS: Volunteers from the general public were invited to take part in the study. Three separate questionnaires were applied to 1) determine the sociodemographic characteristics and health status of the participants, 2) evaluate the quality of their diet, and 3) to evaluate their level of physical activity. The participants underwent somatometry, laboratory tests, liver ultrasound, and FIB-4 index determination, and transition elastography (FibroScan®) was carried out on all subjects with signs suggestive of liver fibrosis that agreed to undergo the procedure. The statistical analysis was carried out using SPSS for Windows, version 22, software. RESULTS: A total of 585 volunteers were studied, resulting in a prevalence of MAFLD of 41.3%, a predominance of men above 50 years of age, poor dietary habits, and sedentary lifestyle. Male sex, obesity, metabolic syndrome, and elevated ALT were risk factors for the disease and 40% of those affected had advanced fibrosis. CONCLUSIONS: The prevalence of MAFLD in our population is one of the highest in the world. The conditioning factors of the disease can be modified. Therefore, public policies that redirect the current trend are required.

Effect of macrocyclic lactones on nontarget coprophilic organisms: a review.

Macrocyclic lactones are frequently used dewormers in livestock farms around the world. Due to their wide spectrum of action against nematodes and arthropods and their practicality of application at very low doses, their use has become massive since their discovery. These compounds are eliminated in a large percentage in the feces of animals, causing adverse effects on coprophilic fauna. Several research groups around the world have been devoted to evaluating these effects on this fauna. The aim of this review is to register the adverse effects of the concentrations in which macrocyclic lactones are eliminated in the feces of domestic animals and the importance of the coprophilic and edaphilous fauna on the degradation of the feces of the animals. The documented data shows that the use of macrocyclic lactones has a high toxicological risk for the different species that colonize the dung, thus causing an adverse effect on its disintegration and its subsequent incorporation into the soil. Even so, more studies at the regional level and their standardization are necessary to make the comparison between different areas possible.

Biochemical characterization of the venom from the Mexican scorpion Centruroides ornatus, a dangerous species to humans.

Every year in Mexico, around 300,000 people suffer from accidents related to scorpion stings. Among the scorpion species dangerous to human is Centruroides ornatus, whose venom characterization is described here. From this venom, a total of 114 components were found using chromatographic separation and mass spectrometry analysis. The most abundant ones have molecular masses between 3000-4000 Da and 6000-8000 Da respectively, similar to other known K+ and Na+-channel specific scorpion peptides. Using intraperitoneal injections into CD1 mice, we were able to identify and fully sequenced three new lethal toxins. We propose to name them Co1, Co2 and Co3 toxins, which correspond to toxins 1 to 3 of the abbreviated species name (Co). Electrophysiology analysis of these peptides using heterologously expressed human Na+-channels revealed a typical ß-toxin effect. Peptide Co52 (the most abundant peptide in the venom) showed no activity in our in vivo and in vitro model assays. A phylogenetic analysis groups the Co1, Co2 and Co3 among other ß-toxins from Centruroides scorpions. Peptide Co52 segregates among peptides of unknown defined functions.

Microscopio como Lector de Absorbancia con Utilidad en Análisis Clínicos / Microscope as Absorbance Reader with Utility in Clinical Analysis

Resumen La descentralización de laboratorios clínicos, se encuentra en desarrollo, lo anterior ha llevado a diseñar instrumentos que ofrecen resultados rápidos, confiables y al lado del paciente, esta tendencia se le conoce como prueba en el punto de atención (point of core testing POCT) y brinda la posibilidad de dar un seguimiento inmediato al padecimiento. El objetivo de esta investigación fue la implementación de un medidor de absorbancia, empleando la estructura de un microscopio óptico, al cual se le ha adaptado un filtro de luz, y una cámara digital. Lo anterior permite obtener valores de intensidad promedio de imágenes sólidas microscópicas de reacciones enzimáticas, y a partir de ellas estimar absorbancia o concentración. Como resultados se presentan rectas de calibración de absorbancia y mediciones de concentraciones para los casos de violeta de genciana, un kit de glucosa oxidasa y muestras problemas de pacientes voluntarios. Concluimos que existe un error de medición menor de ±1mg/dL comparados con las mediciones de un lector de placas de Elisa y un analizador de química sanguínea semiautomatizado. Teniendo en cuenta lo anterior el sistema resulta ser una alternativa viable para la estimación de absorbancia y aumenta la funcionalidad de microscopios ópticos en clínicas de salud.

Abstract The decentralization of clinical laboratories is under development, which has led to the design of instruments that offer fast, reliable and patient-side results, this trend is known as point of core testing (POCT) and It offers the possibility of giving an immediate follow-up to the disease. The objective of this investigation was the implementation of an absorbance meter, using the structure of an optical microscope, to which a light filter and a digital camera have been adapted. This allows to obtain values of average intensity of solid images of enzymatic reactions, and from them to estimate absorbance or concentration. As results, we present absorbance calibration lines and concentration measurements for cases of gentian violet, a glucose oxidase kit and samples of volunteer patients. We conclude that there is a measurement error of less than ± 1mg / dl compared with the measurements of an Elisa plate reader and a semi-automated blood chemistry analyzer. Taking into account the above, the system turns out to be a viable alternative for estimating absorbance and increasing the functionality of optical microscopes in health clinics.

Overexpression of connexin 43 reduces melanoma proliferative and metastatic capacity.

BACKGROUND: Alterations in connexin 43 (Cx43) expression and/or gap junction (GJ)-mediated intercellular communication are implicated in cancer pathogenesis. Herein, we have investigated the role of Cx43 in melanoma cell proliferation and apoptosis sensitivity in vitro, as well as metastatic capability and tumour growth in vivo. METHODS: Connexin 43 expression levels, GJ coupling and proliferation rates were analysed in four different human melanoma cell lines. Furthermore, tumour growth and lung metastasis of high compared with low Cx43-expressing FMS cells were evaluated in vivo using a melanoma xenograft model. RESULTS: Specific inhibition of Cx43 channel activity accelerated melanoma cell proliferation, whereas overexpression of Cx43 increased GJ coupling and reduced cell growth. Moreover, Cx43 overexpression in FMS cells increased basal and tumour necrosis factor-α-induced apoptosis and resulted in decreased melanoma tumour growth and lower number and size of metastatic foci in vivo. CONCLUSIONS: Our findings reveal an important role for Cx43 in intrinsically controlling melanoma growth, death and metastasis, and emphasise the potential use of compounds that selectively enhance Cx43 expression on melanoma in the future chemotherapy and/or immunotherapy protocols.

Barium, TEA and sodium sensitive potassium channels are present in the human placental syncytiotrophoblast apical membrane.

The human placental syncytiotrophoblast (hSTB) is a polarized epithelial structure, without paracellular routes, forming the main barrier for materno-fetal exchange. There is ample evidence suggesting the presence of potassium (K(+)) channels in the placental apical membrane; which could contribute to membrane potential and volume regulation. We have therefore examined the K(+) currents of isolated apical membranes from human term placenta using electrophysiological methods: reconstitution of ion channels from apical membranes into giant liposomes (single channel recordings, patch clamp method) or their functional transplantation into Xenopus laevis oocytes (total currents recording, voltage clamp method). Single channel recording experiments show the presence of K(+) channels in the hSTB microvillous membrane sensitive to Tetraethylammonium (TEA) and Barium (Ba(+2)). Patch current activity was diminished 50% and 70% by 20 mmol/L TEA and 5 mmol/L Ba(+2) respectively. The more frequent conductance was approximately 73pS, however several levels of current were detected suggesting the presence of more than one type of K(+) channel. In addition, sodium (Na(+)) sensitivity was detected in the patch current thus, over 10 mmol/L Na(+) reduced the seal current to 38%. These results were corroborated by the total current experiments where the K(+) current elicited in injected oocytes with apical purified membrane was blocked by Ba(+2) and TEA. The total current was also affected by Na(+), becoming larger when a Na(+)-free solution was used. Our results show the existence of at least two types of Ba(+2)-sensitive K(+) channels including a TEA sensitive sub-population, and some of them Na(+) sensitive K(+) channels. These channels could be the conductive pathways proposed previously for this cation in placental hSTB. Our novel contribution has been to successfully obtain K(+) channel recordings in systems suitable for electrophysiological studies of isolated apical membranes.

Analysis of inherited genetic variants in ret proto-oncogene of Brazilian patients with apparently sporadic medullary thyroid carcinoma.

Mutations in different exons of ret proto-oncogene are responsible for the development of medullary thyroid carcinoma (MTC). The mutations can occur as sporadic or as part of multiple endocrine neoplasia (MEN) type 2 hereditary syndromes. Here we report the first focused study of sporadic MTC in Brazilian patients regarding clinical and molecular analysis of ret proto-oncogene. Our study seeks to estimate the risk of hereditary MTC cases among apparently sporadic cases in a Brazilian population and describe ret genetic variants in their germinative lineage. Germinative sequence variants were screened by DNA sequencing and denaturing gradient gel electrophoresis (DGGE) analysis of exons 10, 11, 13, 14, 15, and 16 of 24 Brazilian patients with apparently sporadic MTC. We identified 1 inherited case of 24 (4%) patients with apparently sporadic MTC. Polymorphisms for the ret proto-oncogene coding region were identified in codon 769 of exon 13 (LeuCTT--> LeuCTG) at a frequency of 13% (3/24) and in codon 904 of exon 15 (SerTCC--> SerTCG) at a frequency of 16.6% (4/24). The observed frequency (4%) of inherited disease among apparent sporadic MTC strengthens routine application of ret proto-oncogene germinative DNA screening in all cases of apparently sporadic MTC ascertained at Brazilian cancer hospitals.

Calidad de superficie obtenida con diferentes métodos de pulido para ionómero de vidrio y resina compuesta / Surface quality obtained by means of different polishing methods for glass ionomer cements and composite resins

El propósito de este estudio fue evaluar tres diferentes métodos de pulido: discos Sof-Lex, fresas de carburo de tungsteno para pulido y piedras de Arkansas, en función de la superficie obtenida en dos materiales: ionómero de vidrio y resina compuesta; todo manipulado de acuerdo a las instrucciones de los fabricantes. Se realizaron 78 muestras, de las cuales 39 fueron de resina y 39 de ionómero. De cada grupo, 6 muestras (3 de cada material) se destinaron para pruebas piloto y doce (seis de cada material) para muestras testigo. Para el procedimiento experimental se destinaron treinta muestras de cada material. Las superficie obtenidas con cada método de pulido fueron evaluadas con un analizador de superficies, y los resultados fueon comparados con los obtenidos del análisis de las superficies testigo: seis obtenidas con presión de cinta Mylar y seis obtenidas por fricción de lija grano 180. Después del análisis estadístico ANOVA se encontró que el uso de Sof-Lex tuvo el mejor resultado

HPV types and cofactors causing cervical cancer in Peru.

We conducted a hospital-based case-control study in Peru of 198 women with histologically confirmed cervical cancer (173 squamous cell carcinomas and 25 cases of adenocarcinoma/adenosquamous carcinoma) and 196 control women. Information on risk factors was obtained by personal interview. Using PCR-based assays on exfoliated cervical cells and biopsy specimens, HPV DNA was detected in 95.3% of women with squamous cell carcinoma and in 92.0% of women with adenocarcinoma/adenosquamous carcinoma compared with 17.7% in control women. The age-adjusted odds ratio was 116.0 (95% Cl = 48.6-276.0) for squamous cell carcinoma and 51.4 (95% Cl = 11.4-232.0) for adenocarcinoma/adenosquamous carcinoma. The commonest types in women with cervical cancer were HPV 16, 18, 31, 52 and 35. The association with the various HPV types was equally strong for the two most common types (HPV 16 and 18) as for the other less common types. In addition to HPV, long-term use of oral contraceptives and smoking were associated with an increased risk. HPV is the main cause of both squamous cell carcinoma and adenocarcinoma in Peruvian women.

TP53 polymorphism, HPV infection, and risk of cervical cancer.

The role of a polymorphism at position 72 of the tumor suppressor gene TP53 in the development of cervical cancer is not well established. The arginine variant of the p53 protein could be more susceptible to degradation by human papillomavirus (HPV) E6 protein than the protein containing proline. Recent studies show controversial results. We investigated a possible association between TP53 polymorphism and cervical cancer in a Peruvian population with high prevalence of HPV infection. HPV status and TP53 polymorphism were determined for 119 cases of invasive cervical cancer and 127 control women from Peru. HPV infection was detected by PCR of cervical cells or tumor biopsies. For determination of TP53 polymorphism, exon 4 of the TP53 gene was amplified by PCR, and DNA was subsequently subjected to restriction enzyme digest. Associations between TP53 polymorphism, HPV infection, and cervical cancer were assessed using logistic regression. Women homozygotes for arginine had a 2.2-fold increased risk (95% confidence interval: 0.6-7.6) for cervical cancer. The odds ratio for women heterozygotes for Arg/Pro was 3.5 (95% confidence interval: 0.9-14). Similarly increased risks were found when restricting analysis to HPV-positive women only. The distribution of TP53 genotypes in this Peruvian population was comparable with that found in Caucasians. Our results cannot rule out an association between the TP53 polymorphism at codon 72, HPV infection, and the etiology of cervical cancer.

Effect of initial glucose concentration and inoculation level of lactic acid bacteria in shrimp waste ensilation.

Fermentation conditions and microorganisms were determined, based on acid production, glucose concentration as carbohydrate source. Inoculation levels to obtain a stable shrimp waste silage were also determined. Shrimp waste ensilation was an efficient method of preservation, allowing the recovery of chitin and another added-value products such as pigments, proteins and enzymes. From the various lactic acid bacteria tested, Lactobacillus pentosus and Lactobacillus sp. (B2) were the best lactic acid producers, although small quantities of acetic acid were detected in samples inoculated with Lactobacillus pentosus. Therefore B2 was chosen for the analysis of glucose consumption as well as for the determination of optimum inoculation levels. The best results were obtained at 10% (w/w wet basis) and 5% (v/w wet basis) respectively. Presence of starters and initial glucose concentration were critical factors in the fermentation of shrimp waste. High initial glucose and starter concentrations reduced the time and increased the amount of lactic acid produced. The fermentation pattern changed during ensilation from hetero to homofermentative. Shrimp waste ensilation prevented the growth of spoilage microorganisms keeping their microbial counts steady and pH values within the acid region.

Estudio comparativo de ionómeros de vidrio y reforzados con metal / A comparative study of glass ionomers and metal-reinforced glass ionomers

El objetivo de este estudio fue comparar algunas propiedades físicas de cementos de ionómero de vidrio, con el fin de confirmar si realmente se incrementan éstas por la adición de partículas de plata. Cinco elementos fueron probados: dos con partículas de plata, de éstos, una mezcla experimental (Degussa tipo II + Aleación de plata Argent FD) y una mezcla comercial (Miracle Mix), uno reforzado con plata por sinterización (Ketac Silver) y dos convencionales tipo II (Fuji y Degussa). Las propiedades valoradas fueron resistencia a la compresión, diametral y a la abrasión. Cinco muestras de cada material fueron hechas para resistencia a la compresión y diametral, de acuerdo a los métodos propuestos por la ANSI/ADA, especificaciones Nros. 66 y 27. Para resistencia a la abrasión las muestras se valoraron de acuerdo a la pérdida de peso y longitud. Todas las pruebas se realizaron después de 24 horas de realizar los mezclados. Los resultados demostraron que la mezcla simple con aleación metálica "mezcla experimental" incrementa estas propiedades mecánicas. Anova (p menor 0.001) y prueba de Tukey indican diferencias entre varios de los cementos valorados

Histological and immunophenotypic profile of nasal NK/T cell lymphomas from Peru: high prevalence of p53 overexpression.

Nasal NK/T-cell lymphoma is a unique form of lymphoma highly associated with Epstein-Barr virus (EBV). These lymphomas are rare in Western populations and much more prevalent in some Asian and Latin American countries. Although there are several sizable studies from Asian countries, the same is not true from South America. The aim of this study was to analyze a series of 32 cases of nasal T-cell lymphoma from Peru and to further extend the characterization of this disease. Immunohistochemistry was performed on paraffin sections using the following antibodies: CD20 (L26), CD45RO, CD3, Ki67, CD57, CD56, TIA-1, bcl-2, and p53. The presence of EBV was investigated with immunohistochemical analysis for latent membrane protein (LMP)-1 and in situ hybridization using an antisense riboprobe to EBER 1. The 32 patients included 18 men and 14 women (M:F ratio, 1.2:1), with a median age of 43 years (11 to 72). Three categories were identified: (1) Nasal NK/T cell lymphomas (28 cases): The morphology ranged from small or medium-sized cells to large transformed cells. Necrosis was present in 86% of the cases, and angioinvasion was seen in 36% of the cases. All cases were positive for CD45RO, CD3, and for TIA-1. CD56 was positive in 21 of 27 cases (78%), and CD57 was negative in all cases. EBER 1 positivity was identified in most of the tumor cells in 27 of 28 cases (96%), including the six cases in which CD56 was negative. Overexpression of p53 was detected in 24 cases (86%). (2) Blastic NK cell lymphoma (1 case): The neoplastic cells resembled those of lymphoblastic lymphoma. CD56 and CD45RO were positive; TIA-1, TdT, and EBER-1 were negative. (3) Peripheral T-cell lymphoma (PTCL) unspecified (3 cases): CD56, TIA-1, and EBER-1 were negative. Nasal lymphomas from Peru with a T cell phenotype are predominantly EBV-associated NK/T cell lymphomas, similar to those described in Asian countries. The expression of CD56, TIA-1, and EBER-1, in combination, are very useful markers for the diagnosis of nasal NK/T cell lymphoma in paraffin-embedded tissue. The differential diagnosis of T-cell lymphomas in the nasal region should include rare cases of PTCL unspecified and the blastic variant of NK cell lymphoma. P53 is overexpressed in 86% of the cases. The significance of this finding with regard to clinical behavior and prognosis remains to be determined.

Microbial spoilage of meats offered for retail sale in Mexico City.

Causes of the food borne epidemics in Mexico City have usually been ascribed to poor handling and preparation of foods. In this work, presence of microorganisms indicative of contamination were analysed in meat sold in Mexico City's retail outlets. Enterobacteriaceae, psycorothrophs, mould and yeast, and mesophile counts, were evaluated in meat from five animal species (beef, sheep, chicken, rabbit and horse). pH, recorded as spoilage indicator, was not significantly different among days of storage nor animal species, conversely, water holding capacity was significantly higher for horse meat. Mesophiles, psychrothrophs and Enterobacteriaceae counts were above legal limits in beef after 5 days of storage at 4°C. This was not observed in rabbit nor chicken meat. Mould and yeast populations remained constant until day 4. Moulds are seldom a problem, whereas yeasts play an important role in the alteration of flavour characteristics. In general, horse had the highest initial microbial counts.

Clonación y transcripción del gen EBER-1 del virus Epstein-Barr: estudio de su expresión genética por hibridación in situ / Cloning and transcription of gene EBER-1 of Epstein-Barr virus: study of its genetic expression by hybridization in situ

La capacidad de virus de Eptein Barr (VEB) de inducir transformación e inmortalización de linfocitos y su alta prevalencia en algunas neoplásias linfoides ha motivado intensa investigación de su biología y comportamiento. Describimos la hibridación in situ (HIS), para la identidicación de transcriptos del virus de Epstein-Barr, desarrollado en la Unidad de Biología Molecular del Centro de Investigación en Cáncer Maes Heller, en biopsias de linfoma incluidas en parafina.El gen EBER-1 (Epstein Barr-encoded RNA) fue clonado y transcrito, el ARN transcrito fue evaluado con óptimos resultados en las líneas celulares Raji y Daudi que expresan EBER. Este transcrito marcado fue usado como sonda para determinar la expresión genética del virus en 159 especimenes biológicos en estudio y en controles positivos y negativos conocidos empleando la HIS.La actividad transcripcional del virus fue observada en 44 de los casos estudiados. Concluimos que la HIS en tejido incluido en parafina es una buena alternativa para detectar actividad del VEB y la presencia o ausencia de EBER puede ser considerada como marcador biológico en la etiopatología de estos linfomas

Oncogenes E6-E7 de los papilomavirus humanos de alto riesgo detectados por PCR en biopsias de pene incluidas en parafina / Oncogenes E6-E7 of the human papillomavirus of high risk detected by PCR in penile biopsia included in paraffin

La alta prevalencia del papilomavirus humano (PVH), referida a nivel mundial, en lesiones genitales de ambos sexos, el rol del varón como reservorio pasivo del virus, y el incremento de la mortalidad por cáncer genital en la mujer en nuestro país, motiva la determinación y correlación de los oncogenes de los PVH de alto riesgo con la neoplasia de pene. Informamos de diez casos de biopsias de carcinoma escamoso de pene, incluidos en parafina, los cuales fueron investigados para la presencia de los oncogenes E6-E7 de PVH de alto riesgo, utilizando cebadores tipo específico para los PVH-16 y 18, mediante la reacción en cadena de polimerasa (PCR). El 40 de los casos mostró un producto de amplificación ADN E6-E7 de los PVH estudiados, correspondiendo el 75 de ellos a detección simple por PVH-18 y el 25 presentó mixta ADN E6-E7 del PVH-16 y 18 simultáneamente. El producto de amplificación fue sometido a comprobación por análisis de restricción específico. La prevalencia obtenida de los oncogenes E6-E7 de los PVH de alto riesgo, usando un método tan sensible como la PCR, apoya el rol de estos virus en el proceso de carcinogénesis de la neoplasia de pene

Effect of calcium chloride marination on calpain and quality characteristics of meat from chicken, horse, cattle and rabbit.

Differences in the quality of meat obtained from four animal species (beef, horse, rabbit and chicken) treated with two concentrations of calcium chloride (75 or 150 mM) were evaluated by a sensory panel. Physicochemical variables analysed were water holding capacity, instrumental colour and pH. Sensory analysis was by recognition index (R-index) by untrained and trained panels. CaCl(2) led to an increase in enzymatic activity, although it was not significantly different in treated compared to untreated samples. Lightness was higher (paler) in treated meat for all species studied. R-index showed that treatment of raw beef with 75mM CaCl(2) had negligible effect on odour compared to fresh, untreated beef. More juicy meat resulted from marination. Treatments with 150 mM CaCl(2) caused a more tender meat. The best combinations of cooking method and CaCl(2) concentration to obtain the most acceptable meat varied from attribute to attribute. The best odour was obtained when beef was treated with 150 mM CaCl(2) and cooked in a convection oven, whereas juiciness was improved if beef was treated with 150 mM CaCl(2) and cooked in a microwave oven. The highest scores for tenderness were for 75 mM CaCl(2)-treated samples regardless of cooking method. Flavour profile showed that the most marked feature in marinated beef is the predominance of a bitter flavour and after taste, which probably masks other flavour attributes. It is concluded that, in accordance with other authors, marination has no adverse effects on beef odour and improves texture, producing more tender material. However, marination at the CaCl(2) levels tested caused a bitter after taste and flavour.

[Factors related to the blood lead level in children 6 to 30 months old in the Prospective Lead Study in Mexico City]. / Factores relacionados con el nivel de plomo en sangre en niños de 6 a 30 meses de edad en el Estudio Prospectivo de Plomo en la Ciudad de México.

A majority of the sample of children (N = 160-121, ages 6-30 months) from the Mexico City Prospective Lead Study exceeds the lowest limit action level (10 micrograms/dl) of the Centers for Disease Control standards for childhood lead exposure. Over one-third of the sample at 18 months and 24 months exceeds the action level (15 micrograms/dl) for aggressive intervention. Diet plays an important role in regulating early childhood blood lead levels. Fresh milk and breast feeding are associated with lower lead levels, but extended breast feeding is related to elevated lead levels. Low income and poor maternal education are associated with higher lead concentration in children. Child consumption of canned milk and juice, up to this date, is associated with elevated child lead levels. Canned products sealed with lead are disappearing from Mexican markets. Efforts to improve childhood nutrition and poverty may be expected to have the additional benefit of lowering lead levels of Mexican children.

Prenatal and postnatal blood lead level and head circumference in children to three years: preliminary results from the Mexico City Prospective Lead Study.

Multiple regression modeling was used to explore the relationship between prenatal and postnatal blood lead levels and child head circumference in the first three years of life. Maternal blood lead at 36 weeks of pregnancy and cord blood lead were found to be inversely related to 6 month and 18 month head circumference, respectively. Child 12 month blood lead was inversely related to 36 month head circumference. Limitations of the data set and the statistical techniques were discussed, as were the interpretations of the findings.

[Sources of lead in pregnant women in the Valley of Mexico]. / Fuentes de plomo en embarazadas de la Cuenca de México.

Lead levels in samples of the groups at highest risk to the effects of lead exposure, pregnant women and their infants, are higher than levels known to produce developmental retardation in children in a considerable proportion of the sample tested in Mexico City. Modeling of prenatal factors predicting maternal lead during pregnancy shows the strong effect of the use of low-temperature ceramics on lead level. The data also suggests an important contribution from air lead. The downward trend in lead exposure in pregnant women in the Valley of Mexico over the last 10 years, concurrent with downward trends in air lead is encouraging. However, reducing the manufacture and use of leaded pottery could produce a significant further reduction of lead exposure with a modest program of public education, government regulation and subsidization of lead free pottery.