Prevalence of obesity, diabetes and hypertension in immigrant populations in northeastern Mexico.

Introduction: Hispanic immigrants are a fast-growing population in the United States of America (USA) that disproportionately suffer from chronic diseases. Despite the increasing prevalence of obesity in Latin-American countries, only a few studies have examined the onset of chronic diseases in Mexican and Central American migrants in Mexico. Objective: The objective of this study is to determine the prevalence of obesity, diabetes, and hypertension in Central American immigrants who are in the process of traveling through northeastern Mexico to the United States. Methods: An observational, descriptive, cross-sectional study was conducted among migrants, mostly Central Americans. Migrants who agreed to participate in the study were interviewed face-to-face by researchers to obtain their sociodemographic data. To obtain the prevalence, many health indicators related to obesity, diabetes, and hypertension, including weight, height, fasting glucose, and blood pressure, were measured. Results: In total, 520 migrants were interviewed; sociodemographic data indicated that most participants were men (76%), from Honduras (72.6%), single (61.2%), and have elementary level of education (48.6%). The somatometric evaluation revealed that 28.9% were diagnosed as overweight, 10.7% with obesity, and 3.3% with malnutrition. Of less prevalence, 8.8% were detected with hypertension and 4.6% had fasting hyperglycemia. The mean participant age was 29.11 ± 10.00 years. For each participant, the average weight was 66.72 ± 13.09 kg; the average height was 1.64 ± 0.08 m; the average body mass index (BMI) was 24.59 ± 4.32; the mean systolic and diastolic pressures were 116.26 ± 15.13 and 74 ± 9.65, respectively; and the average glycemia was 100.97 ± 21.99. El Salvador showed the highest proportion of people with diabetes (14.7%). Women who participated in this study had a higher proportion of obesity (23.4%, p = 0.02) and overweight (36.2%) than men (8.4 and 29.2%, respectively). People from Mexico, Nicaragua, and Honduras reported a high prevalence of overweight participants (63.6, 47.4, and 30.7%, respectively), while people from El Salvador and Nicaragua had a high prevalence of obese participants (23.5 and 21.1%, respectively). Conclusion: We found significant differences in the rates of obesity, diabetes, and hypertension between groups of Central American migrants and their place of origin, age, educational level, and gender. Our findings highlight the importance of exploring differences within groups of Central American migrants traveling through northeastern Mexico to the United States, which may explain several health indicators.

Antigiardial Activity of Foeniculum vulgare Hexane Extract and Some of Its Constituents.

Foeniculum vulgare is used for the treatment of diarrhea in Mexican traditional medicine. Hexane extract showed 94 % inhibition of Giardia duodenalis trophozoites at 300 µg/mL. Therefore, 20 constituents of hexane extract were evaluated to determine their antigiardial activity. Interestingly, six compounds showed good activity toward the parasite. These compounds were (1R,4S) (+)-Camphene (61%), (R)(-)-Carvone (66%), estragole (49%), p-anisaldehyde (67%), 1,3-benzenediol (56%), and trans, trans-2,4-undecadienal (97%). The aldehyde trans, trans-2,4-undecadienal was the most active compound with an IC50 value of 72.11 µg/mL against G. duodenalis trophozoites. This aldehyde was less toxic (IC50 588.8 µg/mL) than positive control metronidazole (IC50 83.5 µg/mL) against Vero cells. The above results could support the use of F. vulgare in Mexican traditional medicine.

Furanocoumarins from Ruta chalepensis with Amebicide Activity.

Entamoeba histolytica (protozoan; family Endomoebidae) is the cause of amoebiasis, a disease related to high morbidity and mortality. Nowadays, this illness is considered a significant public health issue in developing countries. In addition, parasite resistance to conventional medicinal treatment has increased in recent years. Traditional medicine around the world represents a valuable source of alternative treatment for many parasite diseases. In a previous paper, we communicated about the antiprotozoal activity in vitro of the methanolic (MeOH) extract of Ruta chalepensis (Rutaceae) against E. histolytica. The plant is extensively employed in Mexican traditional medicine. The following workup of the MeOH extract of R. chalepensis afforded the furocoumarins rutamarin (1) and chalepin (2), which showed high antiprotozoal activity on Entamoeba histolytica trophozoites employing in vitro tests (IC50 values of 6.52 and 28.95 µg/mL, respectively). Therefore, we offer a full scientific report about the bioguided isolation and the amebicide activity of chalepin and rutamarin.

Latent tuberculosis infection in medical students in the Northeast of Mexico.

BACKGROUND: Medical students are considered to be personnel with a high level of risk for developing latent tuberculosis infection (LTBI). One possible reason is lack of knowledge about the transmission, prevention, and biosafety standards for tuberculosis disease. OBJECTIVE: This research aimed to determine the rate of LTBI among medical students studying in a private School of Medicine in Monterrey, Mexico. METHODS: In this cross-sectional study, we obtained blood samples from 174 medical students. LTBI was diagnosed using the QuantiFERON®-TB Gold Plus test. The prevalence of LTBI was compared with the socio-demographic data of the students and their level of knowledge and use of personal protective equipment (PPE). RESULTS: The proportion of LTBI in the students was 20.6%. Medical students in their first few years of medical school had a lower prevalence of LTBI than students in their final years of medical school. Additionally, students with a low level of knowledge on LTBI and low use of proper PPE had a higher prevalence of LTBI. CONCLUSIONS: In a School of Medicine in Monterrey, Mexico, the proportion of medical students with LTBI was low but the proportion increased in advanced students. Students who demonstrated adequate knowledge and use of respiratory protective masks had lower prevalence rates for LTBI.

Risk Factors for SARS-CoV-2 Infection, Pneumonia, Intubation, and Death in Northeast Mexico.

Despite the social distancing and mobility restriction measures implemented for susceptible people around the world, infections and deaths due to COVID-19 continued to increase, even more so in the first months of 2021 in Mexico. Thus, it is necessary to find risk groups that can benefit from more aggressive preventive measures in a high-density population. This is a case-control study of suspected COVID-19 patients from Nuevo León, Mexico. Cases were: (1) COVID-19-positive patients and COVID-19-positive patients who (2) developed pneumonia, (3) were intubated and (4) died. Controls were: (1) COVID-19-negative patients, (2) COVID-19-positive patients without pneumonia, (3) non-intubated COVID-19-positive patients and (4) surviving COVID-19-positive patients. ≥ 18 years of age, not pregnant, were included. The pre-existing conditions analysed as risk factors were age (years), sex (male), diabetes mellitus, hypertension, chronic obstructive pulmonary disease, asthma, immunosuppression, obesity, cardiovascular disease, chronic kidney disease and smoking. The Mann-Whitney U tests, Chi square and binary logistic regression were used. A total of 56,715 suspected patients were analysed in Nuevo León, México, with 62.6% being positive for COVID-19 and, of those infected, 14% developed pneumonia, 2.9% were intubated and 8.1% died. The mean age of those infected was 44.7 years, while of those complicated it was around 60 years. Older age, male sex, diabetes, hypertension, and obesity were risk factors for infection, complications, and death from COVID-19. This study highlights the importance of timely recognition of the population exposed to pre-existing conditions to prioritise preventive measures against the virus.

Acellular fraction from malignant effusions has cytotoxicity in breast cancer cells.

Malignant ascites (MA) and malignant pleural effusion (MPE) are frequently developed in patients with metastatic cancer; however, the biological properties of these fluids have not been clarified. The present study explored the biological role of a low molecular fraction derived from malignant effusions on the activation of peripheral blood mononuclear cells and on the proliferation of breast cancer cells and fibroblast 55x cells. A <10-kDa fraction from effusions of 41 oncological patients and 34 individuals without cancer was purified, and its potential role in inhibiting nitric oxide (NO) production on lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells was explored, as well as its cytotoxicity on MCF-7 breast cancer cells and fibroblast 55x cells. A significant decrease in NO production was observed in the <10-kDa fraction from malignant effusions. In addition, the acellular fraction from MA decreased the viability of breast cancer cells without affecting human fibroblasts. These data support the presence of low molecular weight molecules in malignant samples with a specific role in inhibiting the defense mechanisms of peripheral blood mononuclear cells and decreasing the viability of breast cancer cells in vitro.

D-Lactate and intestinal fatty acid-binding protein are elevated in serum in patients with acute ischemic stroke.

Experimental studies suggest that the intestinal barrier is affected in ischemic stroke. D-Lactate and intestinal fatty acid-binding protein (IFABP) are markers of intestinal mucosa integrity and barrier function. Our purpose was to evaluate the serum concentrations of these markers in patients with acute ischemic stroke (AIS). We included patients with AIS and used healthy subjects as controls. Clinical, demographic and outcome measures were recorded. Blood was drawn within 24 h of symptom onset. Serum concentrations of D-Lactate and IFABP were determined using commercially available colorimetric and ELISA kits, respectively. We included a total of 61 patients (median age of 64 years). The majority of patients were male (57.4%). The most common cause of stroke was atherosclerosis (34.4%), followed by small-vessel disease and cardioembolic (32.7% each). Mean admission NIHSS score was 8. Median IFABP and D-Lactate concentrations were significantly higher in patients than in controls. Concentrations were not associated with stroke severity or 3-month outcome. Patients with large-artery atherosclerosis and cardioembolic etiology had higher D-Lactate values than patients with small-vessel disease. D-Lactate and IFABP were significantly elevated in patients with AIS. This suggests that there is disruption of the intestinal barrier in patients with AIS.

Antiprotozoal Activity against Entamoeba histolytica of Flavonoids Isolated from Lippia graveolens Kunth.

Amebiasis caused by Entamoeba histolytica is nowadays a serious public health problem worldwide, especially in developing countries. Annually, up to 100,000 deaths occur across the world. Due to the resistance that pathogenic protozoa exhibit against commercial antiprotozoal drugs, a growing emphasis has been placed on plants used in traditional medicine to discover new antiparasitics. Previously, we reported the in vitro antiamoebic activity of a methanolic extract of Lippia graveolens Kunth (Mexican oregano). In this study, we outline the isolation and structure elucidation of antiamoebic compounds occurring in this plant. The subsequent work-up of this methanol extract by bioguided isolation using several chromatographic techniques yielded the flavonoids pinocembrin (1), sakuranetin (2), cirsimaritin (3), and naringenin (4). Structural elucidation of the isolated compounds was achieved by spectroscopic/spectrometric analyses and comparing literature data. These compounds revealed significant antiprotozoal activity against E. histolytica trophozoites using in vitro tests, showing a 50% inhibitory concentration (IC50) ranging from 28 to 154 µg/mL. Amebicide activity of sakuranetin and cirsimaritin is reported for the first time in this study. These research data may help to corroborate the use of this plant in traditional Mexican medicine for the treatment of dyspepsia.

LipF increases rifampicin and streptomycin sensitivity in a Mycobacterium tuberculosis surrogate.

BACKGROUND: Mortality due to tuberculosis (TB) has increased due to the development of drug resistance, the mechanisms of which have not been fully elucidated. Our research group identified a low expression of lipF gene in Mycobacterium tuberculosis clinical isolates with drug resistance. The aim of this work was to evaluate the effect of lipase F (LipF) expression on mycobacterial drug resistance. RESULTS: The effects of expressing lipF from Mycobacterium tuberculosis in Mycobacterium smegmatis on resistance to antituberculosis drugs were determined with resazurin microtiter assay plate and growth kinetics. Functionality of ectopic LipF was confirmed. LipF expression reduced the rifampicin (RIF) and streptomycin (STR) minimum inhibitory concentration (MIC) from 3.12 µg/mL to 1.6 µg/mL and 0.25 µg/mL to 0.06 µg/mL respectively, moreover a reduced M. smegmatis growth in presence of RIF and STR compared with that of a control strain without LipF expression (p < 0.05 and p < 0.01) was shown. CONCLUSIONS: LipF expression was associated with increased RIF and STR sensitivity in mycobacteria. Reduced LipF expression may contribute to the development of RIF and STR resistance in Mycobacterium species. Our findings provide information pertinent to understanding mycobacterial drug resistance mechanisms.

In Vitro Study of Antiamoebic Activity of Methanol Extracts of Argemone mexicana on Trophozoites of Entamoeba histolytica HM1-IMSS.

Infections caused by parasites in humans represent one of the main public health concerns. Amoebiasis, a parasitic infection caused by Entamoeba histolytica (E. histolytica), is considered endemic in Mexico, where Argemone mexicana (A. mexicana) has been used in traditional medicine to treat intestinal parasitic diseases. The objective of this work was to evaluate the potential biological activity of A. mexicana on E. histolytica. For this purpose, a methanolic extract was prepared from A. mexicana leaves, and a differential fractionation was carried out with solvents of different polarities. The inhibitory capacities of the extract and its fractions were evaluated in vitro using HM1-IMSS, a strain of Entamoeba histolytica. A. mexicana extract was found to have a growth-inhibiting activity for E. histolytica, showing IC50 = 78.39 µg/mL. The extract was characterized phytochemically, and the methanolic extract fractions were analyzed by liquid chromatography (HPLC) and mass spectrometry (MS). Berberine and jatrorrhizine were present in the active fractions, and these compounds may be responsible for the antiparasitic activity. The identification of amoebicidal activity of A. mexicana on E. histolytica gives support to the traditional use. Further studies with berberine and jatrorrhizine will be carried out to understand the mechanism involved.

Tocopherol and selenite modulate the transplacental effects induced by sodium arsenite in hamsters.

Human studies suggest that in utero exposure to arsenic results in adverse pregnancy outcomes. The use of dietary supplements, such as sodium selenite (SS) or α-tocopherol succinate (α-TOS), is a reasonable approach to ameliorate such health effects. Sodium arsenite at 100ppm was administered via drinking water to female hamsters from gestational days 1 or 8 to the time of delivery. Viable fetuses, fetal resorptions and non-viable fetuses were recorded during and after pregnancy and total arsenic and its metabolites were characterized in pregnant animals, placentas and fetuses. Arsenic was found to accumulate in the placenta and fetus, increasing fetal mortality, non-viable fetuses and resorptions. Co-administration of SS and α-TOS significantly reduced the observed teratogenic effects. SS influenced arsenic biotransformation by reducing the MMA/InAs index and increasing the DMA/MMA, whereas α-TOS more likely exerts its protective effect through its potent antioxidant activity.

Detection of anti-HspX antibodies and HspX protein in patient sera for the identification of recent latent infection by Mycobacterium tuberculosis.

Mycobacterium tuberculosis is a pathogen causing tuberculosis (TB) a spectrum of disease including acute and asymptomatic latent stages. Identifying and treating latently-infected patients constitutes one of the most important impediments to TB control efforts. Those individuals can remain undiagnosed for decades serving as potential reservoirs for disease reactivation. Tests for the accurate diagnosis of latent infection currently are unavailable. HspX protein (α-crystallin), encoded by Rv2031c gene, is produced in vitro by M. tuberculosis during stationary growth phase and hypoxic or acidic culture conditions. In this study, using standard, and Luminex xMAP® bead capture ELISA, respectively, we report on detection of anti-HspX IgG and IgM antibodies and HspX protein in sera from acute and latent TB patients. For the antibody screen, levels of IgG and IgM antibodies were similar between non-infected and active TB patients; however, individuals classified into the group with latent TB showed higher values of anti-HspX IgM (p = 0.003) compared to active TB patients. Using the bead capture antigen detection assay, HspX protein was detected in sera from 56.5% of putative latent cases (p< 0.050) compared to the background median with an average of 9,900 pg/ml and a range of 1,000 to 36,000 pg/ml. Thus, presence of anti-HspX IgM antibodies and HspX protein in sera may be markers of latent TB.

meso-Dihydroguaiaretic acid derivatives with antibacterial and antimycobacterial activity.

Thirty-three meso-dihydroguaiaretic acid (meso-DGA) derivatives bearing esters, ethers, and amino-ethers were synthesized. All derivatives were tested against twelve drug-resistant clinical isolates of Gram-positive and Gram-negative bacteria, including sensitive (H37Rv) and multidrug-resistant Mycobacterium tuberculosis strains. Among the tested compounds, four esters (7, 11, 13, and 17), one ether (23), and three amino-ethers (30, 31, and 33) exhibited moderate activity against methicillin-resistant Staphylococcus aureus, whereas 30 and 31 showed better results than levofloxacin against vancomycin-resistant Enterococcus faecium. Additionally, nineteen meso-DGA derivatives displayed moderate to potent activity against M. tuberculosis H37Rv with minimum inhibitory concentration (MIC) values ranging from 3.125 to 50µg/mL. Seven meso-DGA derivatives bearing amino-ethers (26-31 and 33) exhibited the lowest MICs against M. tuberculosis H37Rv and G122 strains, with 31 being as potent as ethambutol (MICs of 3.125 and 6.25µg/mL). The presence of positively charged group precursors possessing steric and hydrophobic features (e.g. N-ethylpiperidine moieties in meso-31) resulted essential to significantly increase the antimycobacterial properties of parent meso-DGA as supported by the R-group pharmacophoric and field-based QSAR analyses. To investigate the safety profile of the antimycobacterial compounds, cytotoxicity on Vero cells was determined. The amino-ether 31 exhibited a selectivity index value of 23, which indicate it was more toxic to M. tuberculosis than to mammalian cells. Therefore, 31 can be considered as a promising antitubercular agent for further studies.

A Modified Behavior Risk Factor Surveillance System to Assess Diabetes Self-management Behaviors and Diabetes Care in Monterrey Mexico: A Cross-sectional Study.

Type 2 diabetes mellitus (T2DM) is one of the leading causes of death from worldwide non-communicable diseases. The prevalence of diabetes in the Mexico (MX)-United States border states exceeds the national rate in both countries. The economic burden of diabetes, due to decreased productivity, disability, and medical costs, is staggering and increases significantly when T2DM-related complications occur. The purpose of this study was to use a modified behavioral risk factor surveillance system (BRFSS) to describe the T2DM self-management behaviors, diabetes care, and health perception of a convenience sample of adults with T2DM in Monterrey, MX. This cross-sectional study design, with convenience sampling, was conducted with a convenience sample (n = 351) of adults in the metropolitan area of Monterrey, MX who self-reported a diagnosis of T2DM. Potential participants were recruited from local supermarkets. Twenty-six diabetes and health-related items were selected from the BRFSS and administered in face-to-face interviews by trained data collectors. Data analysis was conducted using descriptive statistics. The mean age was 47 years, and the mean length of time with T2DM was 12 years. The majority was taking oral medication and 34% required insulin. Daily self-monitoring of feet was performed by 56% of the participants; however, only 8.8% engaged in blood glucose self-monitoring. The mean number of health-care provider visits was 9.09 per year, and glycated hemoglobin level (HbA1c) was assessed 2.6 times per year. Finally, only 40.5% of the participants recalled having a dilated eye exam. We conclude the modified BRFSS survey administered in a face-to-face interview format is an appropriate tool for assessing engagement in T2DM self-management behaviors, diabetes care, and health perception. Extension of the use of this survey in a more rigorous design with a larger scale survey is encouraged.

[Not Available]. / Threshold values of sagittal abdominal diameter for the detection of cardio-metabolic risk factors in Northeastern Mexico: a cross-sectional study.

BACKGROUND: The use of sagittal abdominal diameter (SAD) has been proposed for screening cardio-metabolic risk factors; however, its accuracy can be influenced by the choice of thresholds values. AIM: To determine the SAD threshold values for cardio-metabolic risk factors in Mexican adults; to assess whether parallel and serial SAD testing can improve waist circumference (WC) sensitivity and specificity; and to analyze the effect of considering SAD along with WC and body mass index (BMI) in detecting cardio-metabolic risk. METHODS: This cross-sectional study was conducted during 2012-2014 in Northeast Mexico (n = 269). Data on anthropometric, clinical, and biochemical measurements were collected. Sex-adjusted receiver-operating characteristic curves (ROC) were obtained using hypertension, dysglycemia, dyslipidemia and insulin resistance as individual outcomes and metabolic syndrome as a composite outcome. Age-adjusted odds ratios and 95% confidence intervals (CI) were estimated using logistic regression. RESULTS: The threshold value for SAD with acceptable combination of sensitivity and specificity was 24.6 cm in men and 22.5 cm in women. Parallel SAD testing improved WC sensitivity and serial testing improved WC specificity. The co-occurrence of high WC/high SAD increased the risk for insulin resistance by 2.4-fold (95% CI: 1.1-5.3), high BMI/high SAD by 4.3-fold (95% CI: 1.7-11.9) and SAD alone by 2.2-fold (95% CI: 1.2.-4.2). CONCLUSIONS: The use of SAD together with traditional obesity indices such as WC and BMI has advantages over using either of these indices alone. SAD may be a powerful screening tool for interventions for high-risk individuals.

Threshold values of sagittal abdominal diameter for the detection of cardio-metabolic risk factors in Northeastern Mexico: a cross-sectional study / Valores de corte del diámetro sagital del abdomen para la detección de factores de riesgo cardiovascular en el noreste mexicano: estudio transversal

Background: The use of sagittal abdominal diameter (SAD) has been proposed for screening cardio-metabolic risk factors; however, its accuracy can be influenced by the choice of thresholds values. Aim: To determine the SAD threshold values for cardio-metabolic risk factors in Mexican adults; to assess whether parallel and serial SAD testing can improve waist circumference (WC) sensitivity and specificity; and to analyze the effect of considering SAD along with WC and body mass index (BMI) in detecting cardio-metabolic risk. Methods: This cross-sectional study was conducted during 2012-2014 in Northeast Mexico (n = 269). Data on anthropometric, clinical, and biochemical measurements were collected. Sex-adjusted receiver-operating characteristic curves (ROC) were obtained using hypertension, dysglycemia, dyslipidemia and insulin resistance as individual outcomes and metabolic syndrome as a composite outcome. Age-adjusted odds ratios and 95% confidence intervals (CI) were estimated using logistic regression. Results: The threshold value for SAD with acceptable combination of sensitivity and specificity was 24.6 cm in men and 22.5 cm in women. Parallel SAD testing improved WC sensitivity and serial testing improved WC specificity. The co-occurrence of high WC/high SAD increased the risk for insulin resistance by 2.4-fold (95% CI: 1.1-5.3), high BMI/high SAD by 4.3-fold (95% CI: 1.7-11.9) and SAD alone by 2.2-fold (95% CI: 1.2.-4.2). Conclusions: The use of SAD together with traditional obesity indices such as WC and BMI has advantages over using either of these indices alone. SAD may be a powerful screening tool for interventions for high-risk individuals (AU)

Introducción: el diámetro sagital del abdomen (SAD) se ha usado para detectar factores de riesgo cardiometabólicos; su precisión se ve afectada por los valores de corte. Objetivo: determinar valores de corte para factores de riesgo cardiometabólicos en mexicanos adultos; evaluar la sensibilidad y especificidad cuando se utiliza en serie o en paralelo con la circunferencia de la cintura (WC); y analizar el uso del SAD individualmente o junto a WC o el índice de masa corporal (IMC) para detectar factores de riesgo cardiometabólicos. Métodos: en forma transversal, de 2012 a 2014 se estudiaron 209 sujetos provenientes del noreste mexicano. Se recopilaron datos antropométricos, clínicos y bioquímicos. Se construyeron curvas ROC ajustadas por sexo utilizando como resultado individual hipertensión, disglicemia y resistencia a la insulina y como resultado compuesto, el síndrome metabólico. Se calcularon razón de momios e intervalos de confianza (IC 95%) mediante regresión logística. Resultados: los valores de corte fueron 24,6 cm en hombres y 22,5 cm en mujeres. El SAD en paralelo con la WC mejoró sensibilidad y en forma seriada, la especificidad de WC. La coocurrencia de WC y SAD por encima de los rangos incrementó el riesgo para resistencia a la insulina 2,4 veces (95% CI: 1,1-5,3); BMI y SAD elevados, 4,3 veces (95% CI: 1,7-11,9) y SAD individualmente, 2,2 veces (95% CI: 1,2-4,2). Conclusiones: utilizar el SAD junto a índices tradicionales de obesidad (WC y BMI) tiene ventajas sobre su uso individual. El SAD puede ser una poderosa herramienta de tamizaje para intervenciones en individuos de alto riesgo (AU)

An acidic sphingomyelinase Type C activity from Mycobacterium tuberculosis.

Sphingomyelinases (SMases) catalyze the hydrolysis of sphingomyelin to ceramide and phosphorylcholine. Sphingolipids are recognized as diverse and dynamic regulators of a multitude of cellular processes mediating cell cycle control, differentiation, stress response, cell migration, adhesion, and apoptosis. Bacterial SMases are virulence factors for several species of pathogens. Whole cell extracts of Mycobacterium tuberculosis strains H37Rv and CDC1551 were assayed using [N-methyl-(14)C]-sphingomyelin as substrate. Acidic Zn(2+)-dependent SMase activity was identified in both strains. Peak SMase activity was observed at pH 5.5. Interestingly, overall SMase activity levels from CDC1551 extracts are approximately 1/3 of those of H37Rv. The presence of exogenous SMase produced by M. tuberculosis during infection may interfere with the normal host inflammatory response thus allowing the establishment of infection and disease development. This Type C activity is different from previously identified M. tuberculosis SMases. Defining the biochemical characteristics of M. tuberculosis SMases helps to elucidate the roles that these enzymes play during infection and disease.

Actividad de una esfingomielinasa ácida tipo C producida por Mycobacterium tuberculosis / An acidic sphingomyelinase Type C activity from Mycobacterium tuberculosis

Sphingomyelinases (SMases) catalyze the hydrolysis of sphingomyelin to ceramide and phosphorylcholine. Sphingolipids are recognized as diverse and dynamic regulators of a multitude of cellular processes mediating cell cycle control, differentiation, stress response, cell migration, adhesion, and apoptosis. Bacterial SMases are virulence factors for several species of pathogens. Whole cell extracts of Mycobacterium tuberculosis strains H37Rv and CDC1551 were assayed using [N-methyl-14C]-sphingomyelin as substrate. Acidic Zn2+-dependent SMase activity was identified in both strains. Peak SMase activity was observed at pH 5.5. Interestingly, overall SMase activity levels from CDC1551 extracts are approximately 1/3 of those of H37Rv. The presence of exogenous SMase produced by M. tuberculosis during infection may interfere with the normal host inflammatory response thus allowing the establishment of infection and disease development. This Type C activity is different from previously identified M. tuberculosis SMases. Defining the biochemical characteristics of M. tuberculosis SMases helps to elucidate the roles that these enzymes play during infection and disease.

Las esfingomielinasas (SMasas) catalizan la hidrólisis de esfingomielina a ceramida y fosforilcolina. Los esfingolípidos son reconocidos como reguladores diversos y dinámicos de una multitud de procesos celulares que median en el control del ciclo celular, la diferenciación, la respuesta al estrés, la migración celular, la adhesión y la apoptosis. Las esfingomielinasas bacterianas son factores de virulencia reconocidos en varias especies de patógenos. En este trabajo se analizaron los extractos de células enteras de las cepas de Mycobacterium tuberculosis H37Rv y CDC1551 utilizando [N-metil-14C]-esfingomielina como sustrato. Se identificó actividad de SMasa-ácida dependiente de zinc en ambas cepas. La actividad máxima se observó a pH 5.5. Curiosamente, los niveles de actividad de SMasa generados a partir de extractos de la cepa CDC1551 son aproximadamente un tercio de los de la cepa H37Rv. La presencia de una SMasa exógena producida por M. tuberculosis durante la infección puede interferir con la respuesta inflamatoria del huésped, permitiendo así el establecimiento de la infección y el desarrollo de la enfermedad. Esta actividad tipo C es distinta de las actividades previamente reportadas para M. tuberculosis. Definir las características bioquímicas de las esfingomielinasas de M. tuberculosis ayudará a dilucidar el papel que desempeñan estas enzimas durante la infección y la enfermedad.

Interferon Gamma-Based Detection of Latent Tuberculosis Infection in the Border States of Nuevo Leon and Tamaulipas, Mexico.

Nearly one-third of the world's population is infected with latent tuberculosis (LTBI). Tuberculosis (TB) rates in the border states are higher than national rates in both the US and Mexico, with the border accounting for 30% of total registered TB cases in both countries. However, LTBI rates in the general population in Mexican border states are unknown. In this region, LTBI is diagnosed using the tuberculin skin test (TST). New methods of detection more specific than TST have been developed, although there is currently no gold standard for LTBI detection. Our objective is to demonstrate utility of the Quantiferon TB gold In-Tube (QFT-GIT) test compared with the TST to detect LTBI among border populations. This is an observational, cross-sectional study carried out in border areas of the states of Nuevo Leon and Tamaulipas, Mexico. Participants (n = 210) provided a TST and blood sample for the QFT-GIT. Kappa coefficients assessed the agreement between TST and QFT-GIT. Participant characteristics were compared using Fisher exact tests. Thirty-eight percent of participants were diagnosed with LTBI by QFT-GIT. The proportion of LTBI detected using QFT-GIT was almost double [38% (79/210)] that found by TST [19% (39/210)] (P < 0.001). Concordance between TST and QFT-GIT was low (kappa = 0.37). We recommend further studies utilizing the QFT-GIT test to detect LTBI among border populations.