Because S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) are the substrate and product of essential methyltransferase reactions; the ratio of SAM:SAH is frequently used as an indicator of cellular methylation potential. However, it is not clear from the ratio whether substrate insufficiency, product inhibition or both are required to negatively affect cellular methylation capacity. A combined genetic and dietary approach was used to modulate intracellular concentrations of SAM and SAH. Wild-type (WT) or heterozygous cystathionine β-synthase (CBS +/−) mice consumed a control or methyl-deficient diet for 24 wk. The independent and combined effect of genotype and diet on SAM, SAH and the SAM:SAH ratio were assessed in liver, kidney, brain and testes and were correlated with relative changes in tissue-specific global DNA methylation. The combined results from the different tissues indicated that a decrease in SAM alone was not sufficient to affect DNA methylation in this model, whereas an increase in SAH, either alone or associated with a decrease in SAM, was most consistently associated with DNA hypomethylation. A decrease in SAM:SAH ratio was predictive of reduced methylation capacity only when associated with an increase in SAH; a decrease in the SAM:SAH ratio due to SAM depletion alone was not sufficient to affect DNA methylation in this model. Plasma homocysteine levels were positively correlated with intracellular SAH levels in all tissues except kidney. These results support the possibility that plasma SAH concentrations may provide a sensitive biomarker for cellular methylation status.

The demography, survival, and motor phenotypes of amyotrophic lateral sclerosis (ALS) patients have been rarely described in Hispanic countries. The clinical characteristics and survival of a series of Mexican ALS patients are described. Mexican patients with definite ALS were included in a five-year retrospective longitudinal study. Their demographic and clinical features, cumulative survival rates, and independent predictive factors for survival were analysed. Sixty-one definite ALS patients were included. The median follow-up period was 35 months (range 12–108 months). Males were predominant (1.8: 1), the mean age at onset was 47.5 ± 10.5 years, and the median interval from onset to diagnosis was 12 months. Spinal onset occurred in 66% of patients. Upper motor neuron phenotype was predominant in 53% of patients. The overall mean survival from onset was 68.6 months, and from diagnosis was 57.8 months. Longer survival was determined in patients aged ≤ 40 years (54.7 months) compared with other age groups (p = 0.006). In conclusion, the clinical heterogeneity, male predominance, and survival rates in our sample are consistent with those of other studies. Patients in this series had a younger age at onset and a clear trend toward longer survival compared with those of other population studies.

This study examines the spatial structure of children with cleft lip and palate (CLP) and its association with polluted areas in the Monterrey Metropolitan Area (MMA). The Nearest Neighbor Index (NNI) and the Spatial Statistical Scan (SaTScan) determined that the CLP cases are agglomerated in spatial clusters distributed in different areas of the city, some of them grouping up to 12 cases of CLP in a radius of 1.2 km. The application of the interpolation by empirical Bayesian kriging (EBK) and the inverse distance weighted (IDW) method showed that 95% of the cases have a spatial interaction with values of particulate matter (PM₁₀) of more than 50 points. The study also shows that 83% of the cases interacted with around 2000 annual tons of greenhouse gases. This study may contribute to other investigations applying techniques for the identification of environmental and genetic factors possibly associated with congenital malformations and for determining the influence of contaminating substances in the incidence of these diseases, particularly CLP.

This study identified risk factors for health and access to healthcare services of migrants during their journey across Mexico to the United States. Data were collected in shelters located in Monterrey, the largest city of northeastern Mexico, through a basic clinical examination and a survey completed by 75 migrants; 92% of them were undocumented Central Americans. During their transit, they are at a high risk of contracting, developing, and transmitting diseases. The need of working to survive affects health-seeking behavior and a constant fear of being traced keeps migrants away from public health services, which delays diagnosis and treatment of diseases. Negligent lifestyles, such as smoking, drinking (31.8% of men and 11.1% of women), and drug abuse (13% of men and 11% of women), were found. Regarding tuberculosis (TB), undocumented migrants are usually not screened, even though they come from countries with a high TB burden. Besides, they might be overexposed to TB because of their living conditions in overcrowded places with deficient hygiene, protection, and malnutrition (54.7% of the sample). Possible comorbidities like acquired immune deficiency syndrome (AIDS; 4%) and diabetes (2.7%, but probably under-diagnosed) were referred. Migrants have little TB knowledge, which is independent of their level of education or a previous experience of deportation. About one-third of the migrants were totally unfamiliar with TB-related symptoms, while 36% had correct knowledge of basic TB symptoms. We conclude that a shortage of information on the highly vulnerable migratory population combined with a lack of social support and health education among migrants may play a significant role in the spread of communicable diseases. We recommend that health authorities address this urgent, binational, public health concern, in order to prevent outbreaks of emerging infections.

The Monterrey Metropolitan Area (MMA) in Northeast Mexico has shown high PM_2.5 concentrations since 2003. The data shows that the annual average concentration exceeds from 2 to 3 times the Mexican PM_2.5 annual air quality standard of 12 µg/m³. In a previous work we studied the chemical characterization of PM_2.5 in two sites of the MMA during the winter season. Among the most important components we found ammonium sulfate and nitrate, elemental and organic carbon, and crustal matter. In this work we present the results of a second chemical characterization study performed during the summer time and the application of the chemical mass balance (CMB) model to determine the source apportionment of air pollutants in the region. The chemical analysis results show that the chemical composition of PM_2.5 is similar in both sites and periods of the year. The results of the chemical analysis and the CMB model show that industrial, traffic, and combustion activities in the area are the major sources of primary PM_2.5 and precursor gases of secondary inorganic and organic aerosol (SO₂, NOx, NH₃, and volatile organic compounds [VOCs]). We also found that black carbon and organic carbon are important components of PM_2.5 in the MMA. These results are consistent with the MMA emission inventory that reports as major sources of particles and SO₂ a refinery and fuel combustion, as well as nitrogen oxides and ammonium from transportation and industrial activities in the MMA and ammonium form agricultural activities in the state. The results of this work are important to identify and support effective actions to reduce direct emissions of PM_2.5 and its precursor gases to improve air quality in the MMA. Implications: The Monterrey Metropolitan Area (MMA) has been classified as the most air-polluted area in Mexico by the World Health Organization (WHO). Effective actions need to be taken to control primary sources of PM_2.5 and its precursors, reducing health risks on the population exposed and their associated costs. The results of this study identify the main sources and their estimated contribution to PM_2.5 mass concentration, providing valuable information to the local environmental authorities to take decisions on PM_2.5 control strategies in the MMA.

Abstract: We investigated the microbiological and toxicological effects of three Perla black bean extracts on the growth and culture of selected pathogenic microorganisms, the toxicity over Vero cell lines and anin vivorat model. Three different solvents were used to obtain Perla black bean extracts. All three Perla black bean extracts were tested for antibacterial and antiparasitic activity and further analysed for intrinsic cytotoxicity (IC₅₀). Methanol Perla black bean extract was used for acute toxicity test in rats, with the up‐and‐down doping method. All Perla black bean extracts inhibited bacterial growth.Pseudomonas aeruginosa,Proteus vulgaris,Klebsiella oxytoca,Enterococcus faecalis,Staphylococcus aureus,Staphylococcus epidermidisandListeria monocytogenesshowed inhibition, whileEscherichia coliandEnterobacter aerogenesdid not. Acidified water and acetic acid Perla black bean extract were tested in parasites. The best IC₅₀was observed forGiardia lamblia, while higher concentrations were active againstEntamoeba histolyticaandTrichomonas vaginalis. The Vero cells toxicity levels (IC₅₀) for methanol, acidified water and acetic acid Perla black bean extract were [mean ± S.D. (95% CI)]: 275 ± 6.2 (267.9–282.0), 390 ± 4.6 (384.8–395.2) and 209 ± 3.39 (205.6–212.4) µg/ml, respectively.In vivoacute toxicity assays did not show changes in absolute organ weights, gross and histological examinations of selected tissues or functional tests. The acetic acid and methanol Perla black bean extract proved to exhibit strong antibacterial activity and the acidified water Perla black bean extract exerted parasiticidal effects againstGiardia lamblia,Entamoeba hystoliticaandTrichomonas vaginalis. The three Perla black bean extracts assayed over Vero cells showed very low toxicity and the methanol Perla black bean extractin vivodid not cause toxicity.