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Abstract Background We explored the imputation performance of the program IMPUTE in an admixed sample from Mexico City. The following issues were evaluated: (a) the impact of different reference panels (HapMap vs. 1000 Genomes) on imputation; (b) potential differences in imputation performance between single-step vs. two-step (phasing and imputation) approaches; (c) the effect of different INFO score thresholds on imputation performance and (d) imputation performance in common vs. rare markers. Methods The sample from Mexico City comprised 1,310 individuals genotyped with the Affymetrix 5.0 array. We randomly masked 5% of the markers directly genotyped on chromosome 12 (n = 1,046) and compared the imputed genotypes with the microarray genotype calls. Imputation was carried out with the program IMPUTE. The concordance rates between the imputed and observed genotypes were used as a measure of imputation accuracy and the proportion of non-missing genotypes as a measure of imputation efficacy. Results The single-step imputation approach produced slightly higher concordance rates than the two-step strategy (99.1% vs. 98.4% when using the HapMap phase II combined panel), but at the expense of a lower proportion of non-missing genotypes (85.5% vs. 90.1%). The 1,000 Genomes reference sample produced similar concordance rates to the HapMap phase II panel (98.4% for both datasets, using the two-step strategy). However, the 1000 Genomes reference sample increased substantially the proportion of non-missing genotypes (94.7% vs. 90.1%). Rare variants ( Conclusions The program IMPUTE had an excellent imputation performance for common alleles in an admixed sample from Mexico City, which has primarily Native American (62%) and European (33%) contributions. Genotype concordances were higher than 98.4% using all the imputation strategies, in spite of the fact that no Native American samples are present in the HapMap and 1000 Genomes reference panels. The best balance of imputation accuracy and efficiency was obtained with the 1,000 Genomes panel. Rare variants were not captured effectively by any of the available panels, emphasizing the need to be cautious in the interpretation of association results for imputed rare variants.

Background: Permanent occupational disability is one of the most severe consequences of diabetes that impedes the performance of usual working activities among economically active individuals. Survival rates and worker compensation expenses have not previously been examined among Mexican workers. We aimed to describe the worker compensation expenses derived from pension payments and also to examine the survival rates and characteristics associated with all-cause mortality, in a cohort of 34,014 Mexican workers with permanent occupational disability caused by diabetes during the years 2000-2013 at the Mexican Institute of Social Security., Methods: A cross-sectional analysis study was conducted using national administrative records data from the entire country, regarding permanent occupational disability medical certification, pension payment and vital status. Survival rates were estimated using the Kaplan-Meier method. Multivariate Cox proportional hazard model was used to estimate adjusted hazard ratios (HR) and 95 % confidence intervals (95 % CI) in order to assess the cohort characteristics and all-cause mortality risk. Total expenses derived from pension payments for the period were accounted for in U.S. dollars (USD, 2013)., Results: There were 12,917 deaths in 142,725.1 person-years. Median survival time was 7.26 years. After multivariate adjusted analysis, males (HR, 1.39; 95 % CI, 1.29-1.50), agricultural, forestry, and fishery workers (HR, 1.41; 95 % CI, 1.15-1.73) and renal complications (HR, 3.49; 95 % CI, 3.18-3.83) had the highest association with all-cause mortality. The all-period expenses derived from pension payments amounted to $777.78 million USD (2013), and showed a sustained increment: from $58.28 million USD in 2000 to $111.62 million USD in 2013 (percentage increase of 91.5 %)., Conclusions: Mexican workers with permanent occupational disability caused by diabetes had a median survival of 7.26 years, and those with renal complications showed the lowest survival in the cohort. Expenses derived from pension payments amounted to $ 777 million USD and showed an important increase from 2000 to 2013.

Background: The lower extremity amputations diminish the quality of life of patients with Diabetes Mellitus (DM). The aim of this study was to describe the lower extremity amputation rates in subjects with DM in the Mexican Social Security Institute (IMSS), comparing 2004 and 2013., Methods: A comparative cross-sectional study was done. Amputations were identified from the hospital records of System of Medical Statistics (DataMart). The DM patient census was obtained from the System of Integral Attention to Health. Major and minor amputations rates were expressed per 100,000 DM patients., Results: We observed 2 334 340 and 3 416 643 DM patients during 2004 and 2013, respectively. The average age at the time of the amputation was similar in 2004 and 2013 (61.7 and 65.6 years old for minor and major amputations respectively). The major amputations rates were 100.9 and 111.1 per 100 000 subjects with DM in during 2004 and 2013 (p = 0.001); while minor amputations rates were 168.8 and 162.5 per 100 000 subjects with DM in during 2004 and 2013 respectively (p = 0.069)., Conclusions: The lower extremity amputations rates at IMSS are very high compared with that reported in developed countries. The major amputations rate increased in 2013 compared with 2004.

Background: In recent years, medical practice has followed two different paradigms: evidence-based medicine (EBM) and values-based medicine (VBM). There is an urgent need to promote medical education that strengthens the relationship between these two paradigms. This work is designed to establish the foundations for a continuing medical education (CME) program aimed at encouraging the dialogue between EBM and VBM by determining the values relevant to everyday medical activities., Methods: A quasi-experimental, observational, comparative, prospective and qualitative study was conducted by analyzing through a concurrent triangulation strategy the correlation between healthcare personnel-patient relationship, healthcare personnel's life history, and ethical judgments regarding dilemmas that arise in daily clinical practice.In 2009, healthcare personnel working in Mexico were invited to participate in a free, online clinical ethics course. Each participant responded to a set of online survey instruments before and after the CME program. Face-to-face semi-structured interviews were conducted with healthcare personnel, focusing on their views and representations of clinical practice., Results: The healthcare personnel's core values were honesty and respect. There were significant differences in the clinical practice axiology before and after the course (P <0.001); notably, autonomy climbed from the 10th (order mean (OM) = 8.00) to the 3rd position (OM = 5.86). In ethical discernment, the CME program had an impact on autonomy (P ≤0.0001). Utilitarian autonomy was reinforced in the participants (P ≤0.0001). Regarding work values, significant differences due to the CME intervention were found in openness to change (OC) (P <0.000), self-transcendence (ST) (P <0.001), and self-enhancement (SE) (P <0.019). Predominant values in life history, ethical discernment and healthcare personnel-patient relation were beneficence, respect and compassion, respectively., Conclusions: The healthcare personnel participating in a CME intervention in clinical ethics improved high-order values: Openness to change (OC) and Self Transcendence (ST), which are essential to fulfilling the healing ends of medicine. The CME intervention strengthened the role of educators and advisors with respect to healthcare personnel. The ethical values developed by healthcare professionals arise from their life history and their professional formation.

The aim of this study was to determine the frequency of drug resistance and the clonality of genotype patterns in M. tuberculosis clinical isolates from pediatric patients in Mexico (n = 90 patients from 19 states; time period-January 2002 to December 2003). Pulmonary disease was the most frequent clinical manifestation (71%). Children with systemic tuberculosis (TB) were significantly younger compared to patients with localized TB infections (mean 7.7 ± 6.2 years versus 15 ± 3.4 years P = 0.001). Resistance to any anti-TB drug was detected in 24/90 (26.7%) of the isolates; 21/90 (23.3%) and 10/90 (11.1%) were resistant to Isoniazid and Rifampicin, respectively, and 10/90 (11.1%) strains were multidrug-resistant (MDR). Spoligotyping produced a total of 55 different patterns; 12/55 corresponded to clustered isolates (n = 47, clustering rate of 52.2%), and 43/55 to unclustered isolates (19 patterns were designated as orphan by the SITVIT2 database). Database comparison led to designation of 36 shared types (SITs); 32 SITs (n = 65 isolates) matched a preexisting shared type in SITVIT2, whereas 4 SITs (n = 6 isolates) were newly created. Lineage classification based on principal genetic groups (PGG) revealed that 10% of the strains belonged to PGG1 (Bovis and Manu lineages). Among PGG2/3 group, the most predominant clade was the Latin-American and Mediterranean (LAM) in 27.8% of isolates, followed by Haarlem and T lineages. The number of single drug-resistant (DR) and multidrug-resistant (MDR-TB) isolates in this study was similar to previously reported in studies from adult population with risk factors. No association between the spoligotype, age, region, or resistance pattern was observed. However, contrary to a study on M. tuberculosis spoligotyping in Acapulco city that characterized a single cluster of SIT19 corresponding to the EAI2-Manila lineage in 70 (26%) of patients, not a single SIT19 isolate was found in our pediatric patient population. Neither did we find any shared type belonging to the EAI family which represents ancestral PGG1 strains within the M. tuberculosis complex. We conclude that the population structure of pediatric TB in our setting is different from the one prevailing in adult TB patient population of Guerrero.

The knowledge of the molecular basis of diabetes mellitus physiopathology will allow improvements in treatment or prevention of the disease. Diabetes mellitus is a complex disease in which hyperglycemia leads to complications in several organs. In this condition, there is increase in reactive oxygen species (ROS) as a result of glucose autooxidation; its metabolism produces accumulation of metabolites such as fructose, sorbitol, and triose phosphate. The latter generates a oxoaldehydes with high capacity to produce protein glycation and oxidative stress. Moreover, there is an increase in synthesis of diacylglycerol from triosephosphate, which activates protein kinase C. On the other hand, alteration of normal ratio between reduced and oxidized niacinamide nucleotides leads to low efficiency of antioxidative systems. Finally, this metabolic dysregulation causes altered signal transduction, abnormal gene expression, and tissue damage, resulting in development of diabetic complications.

The present work describes the anti-measles vaccination program by the inhaled aerosol method undertaken in Mexico between 1988 and 1990. Detailed descriptions are given of the equipment, staff, training programs, promotion and campaigns. The vaccine is specified: Edmonston-Zagreb strain cultured in diploid cells at the Instituto Nacional de Virología of the Secretaría de Salud in Mexico with titres varying from 1045 plaque forming units (PFU/ml) to 1048 PFU/ml administered in a 30 sec inhalation with aerosol. During this exposure period, 2800 to 4000 PFU per child are estimated to enter the child, of which approximately 25% is the retained doses, i.e. 700 to 1000 PFU/child. A total of 3760684 children of school and pre-school age have been vaccinated in 13 of the 32 federal entities of the country. No undesirable effects of any importance were observed, and the limited serological and field studies support the effectiveness and security of this method. On the other hand, the method is much cheaper, faster and better accepted by the population than the subcutaneous injection.

A brief description of the effects that smallpox caused in the worldwide population places the events that gave rise to the evolution of the concept and practice of the smallpox vaccine in context. Through a description of various events in Jenner's life in relation to his study and use of inoculation, the lessons that have been learned from the dissemination of the technique and the development of smallpox vaccination campaigns and programs throughout the world are commented on. The article indicates that the analysis of the process that culminated in the eradication of smallpox has current applications in programs underway to control, eliminate and eventually eradicate certain diseases. Finally, some lessons are highlighted that have been used in successful national, regional and worldwide vaccination campaigns in the struggle against other infectious diseases.

A comparative study of two different staining methods for estimation of yeast's viability is assessed by microbial flow cytometry. Propidium iodide (PI) a well known nucleic-acid binding vital dye exclusion is compared with light green (LG), a cytoplasmic function related vital dye widely used in histological, histochemical and immunocytochemical staining. The yeast model used was heat-killed Candida guilliermondii cells. The stained heat-killed bacterial population showed on the dot-plot flow cytometer analysis, a clear separation towards the green-orange (350-600 nm) for LG, and orange-red (550-725 nm) for PI on the fluorescence spectrum-zone channels. Both dyes showed by non-parametric Kolmcgorov-Smirnov, 99% of probability of difference between heat-killed and live microorganism's histogram-population, with a D = ranking from 0.50-0.64 for LG to 0.91-0.98 for PI. Higher cost and carcinogenic risk when handling PI, make LG a better choice for flow cytometry yeast viability tests.

We propose that the ratios of lymphocyte subsets: CD4+/CD8+, CD4+/CD3+, and CD8+/CD3+, graphically displayed in this order, could be an easy way of immunophenotyping and a simple form of interpretation both for clinicians and patients. A total of 187 asymptomatic HIV-positive patients, -including 83 symptomatic patients with AIDS- and a normal comparative age group of 36 patients, were studied by flow cytometry. Ratios were graphically displayed on millimetric-grid paper, and a specific point was given to each obtained ratio. The points were connected by a line. The angles formed by the lines were measured and graphically displayed over a circle. The point of reference 0 degree was located on the left side of the circle, giving the corresponding 90 degrees, 180 degrees, and 240 degrees angles. The graph of the control group shows a "beach chair" image. As soon as the CD4+ lymphocytes diminish and the CD8+ lymphocytes increase in HIV+ patients, "the chair's headrest" descends and the "chair's footpiece" swivels back. Given the ranks and fluctuations of the lymphocyte subsets, their graphic display provides a better representation of the immunological status.

A total of 72 peptonated water samples suspected of carrying Vibrio cholerae were assessed by laser flow cytometry (LFC) and compared with positive culture. We used a direct fluorescence technique using polyclonal (PolAb) and monoclonal antibodies (MoAb) conjugated to fluorescein. The PolAb were able to detect 33 positive samples. A clear difference among the 20 positive samples was found with only three V. cholerae O1 false negatives when MoAb were used whereas all 13 V. cholerae Non O1 samples were detected. The correlation index comparing control autofluorescence with peptonated water samples show a R = 0.69, versus 0.96 with pure V. cholerae O1 strains. Our data suggest that the LFC technique is able to recognize V. cholerae O1 from a mixture of microorganisms with high sensitivity and specificity in a few hours.

The treatment received by children aged under 5 years with diarrhoea was studied in the Hospital Infantil de México (Federico Goméz), Mexico City. The costs of treatment were calculated and estimates were made of how these had changed since the establishment of an oral rehydration unit in the hospital in 1985. The results indicate that drug treatment of outpatients was generally appropriate and inexpensive. In contrast, the cost of drugs for inpatients was considerably higher. The seriousness of the cases justified much of this additional expense for inpatients, but there is evidence that the costs could be reduced further without jeopardizing the quality of the care. Diagnostic tests were relatively expensive, frequently failed to identify diarrhoeal etiology, and their results correlated poorly with the treatment prescribed. The oral rehydration unit resulted in significant savings by causing a 25% fall in the number of inpatients with diarrhoea.