Systemic Sclerosis: Elevated Levels of Leukotrienes in Saliva and Plasma Are Associated with Vascular Manifestations and Nailfold Capillaroscopic Abnormalities.

The role of leukotrienes (LTs) in the pathogenesis of systemic sclerosis (SSc) needs clarification. We analyzed the association of salivary (sa) and plasma (p) levels (pg/mL) of cysteinyl-leukotrienes (CysLT) and LTB4 with SSc vascular manifestations and nailfold capillaroscopy (NFC) in a cross-sectional study. Patients and healthy controls were evaluated for vascular manifestations and NFC. LTs were compared between groups as follows: SSc with or SSc without vascular features and controls, and by NFC parameters. Twenty SSc patients and 16 volunteers were recruited; Raynaud's phenomenon (RP) history (SSc: saCysLT 99.4 ± 21.8 vs. controls: 23.05 ± 23.7, p = 0.01), RP at examination (SSc: saCysLT 129.3 ± 24.6 vs. controls: 23.05 ± 22.46, p = 0.01; pCysLT SSc: 87.5 ± 11.2 vs. controls: 32.37 ± 10.75, p = 0.002), capillary loss (saCysLT 138.6 ± 26.7 vs. 23.05 ± 21.6, p = 0.0007; saLTB4 3380.9 ± 426.6 vs. 1216.33 ± 346.1, p = 0.0005), "late" scleroderma pattern vs. controls (saCysLT 205.6 ± 32 vs. 23 ± 19.6, p = 0.0002; saLTB4 4564.9 ± 503.6 vs. 1216.3 ± 308.3; p < 0.0001) were all significant. Late patterns had higher levels (saCysLT, p = 0.002; LTB4 p = 0.0006) compared to active and early patterns (LTB4, p = 0.0006), and giant capillaries (p = 0.01) showed higher levels of LTs. Levels of pCysLT were higher in patients with RP at examination vs. patients without RP; saCysLT and LTB4 were higher in SSc group with vs. without capillary loss. LTs could be involved in the pathophysiology of vascular abnormalities. Further research is required to determine if blocking LTs could be a therapeutic target for SSc vascular manifestations.

Social Class for Collective Health Research: A Conceptual and Empirical Challenge.

Social Determination of Health (SDH)/Collective Health is a Latin American framework that sees the Marxist core concept of social class as fundamental for understanding health inequalities. In contrast to social stratification approaches, Marxist proposals seek to understand health as part of the historical transformations of capitalism's mode of production. In this article we aim to analyze the relationship between social class and health inequalities using data from the IV Oral Health National Study in Colombia. We conducted hierarchical cluster analyses to classify the population in five class positions and three living conditions clusters, which reflect how the spheres of production and social reproduction relate to social classes in Colombia. To measure oral health we use DMFT, as well as care and treatment needs indexes. Through variance analysis models we found that people from more exploited class positions and worse living conditions have more active disease and higher treatment needs. Despite technical and conceptual challenges, we conclude that a social class analytical framework can be operationalised via the interrelated spheres of production and social reproduction, which sheds light on the relationship between health inequalities and the class structure of the capitalist system.

Problemas del lenguaje en niños con parálisis cerebral / Language problems in children with cerebral palsy

La parálisis cerebral es una lesión no progresiva en las estructuras cerebrales que genera un trastorno del movimiento y de la postura. Estas lesiones también pueden afectar otras áreas responsables del desarrollo del lenguaje, tales como el sistema del habla, el sistema lingüístico o el procesamiento léxico, además de conllevar otras comorbilidades en diversas áreas. Objetivo. . Constatar el desarrollo del sistema lingüístico mediante la longitud media de los enunciados verbales y analizar el desempeño del procesamiento léxico que presentaron 142 niños mexicanos con parálisis cerebral cuyas edades comprendían de los 7 a los 13 años. Material y métodos. Mediante una elicitación de datos controlados la población debían nombrar 107 entidades clasificadas en 12 campos semánticos y contar el cuento Frog, Where are you? («Dónde está la ranita») siguiendo las imágenes de la historia para comprobar su longitud media de los enunciados verbales. Results. Solo el 16.9% de estos niños lograron nombrar más de 50 imágenes y contar el cuento que se les había mostrado. La longitud media de los enunciados verbales solo correspondió con la edad cronológica de un solo niño; el resto estuvo por debajo de lo esperado. El 83.1% de los 142 niños con parálisis cerebral evaluados no lograron emitir más de 10 palabras en ambas elicitaciones (AU)

Cerebral palsy is a non-progressive lesion in the brain structures that generates a disorder of movement and posture. These lesions can also affect other areas responsible for the language development system such as speech, linguistic or lexical retrieval system, as well as leading to other comorbidities in various areas. Objective. To observe the development of the language system using the Mean Length of Utterance and an analysis of the lexical retrieval presented in 142 Mexican children with cerebral palsy with ages ranging from 7 to 13 years. Material and methods. Using controlled data elicitation, the children with Cerebral Palsy were to name 107 entities (images) classified into 12 semantic fields and tell a story about «Frog, Where are you?», following the images of the story in order to check the Mean Length of Utterances. Results. Only 16.9% of these children were able to name more than 50 images that were shown and tell a story. The Mean Length of Utterance only corresponded with the chronological age in just one child, with the rest being lower than expected. The vast majority (83.1%) of the 142 children with palsy cerebral assessed did not exceed 10 words (AU)

[Level of clinical competence in seven cohorts of medical students at the end of the internship]. / Grado de competencia clínica de siete generaciones de estudiantes al término del internado médico de pregrado.

INTRODUCTION: Objective structured clinical examination is the instrument with more validated evidence to assess the degree of clinical competence of medical students. OBJECTIVES: To assess the degree of clinical competence of medical students at the end of their internship; to assess the reliability of the instruments with G theory. METHODS: This was an observational, longitudinal, and comparative study. The target population was composed of 5,399 interns of seven generations that finished their internship at the Faculty of Medicine of UNAM, between 2009 and 2015. The instrument used was 18 OSCE stations, three in each subject of the internship. RESULTS: The undergraduate medical interns show a sufficient degree of clinical competence to be general practitioners. The laboratory interpretation and physical examination had the highest scores. The interpretation of imaging studies was the component with the lowest score. The Family Medicine disciplinal area had the highest average score in the OSCE; in contrast, Pediatrics obtained the lowest score on average. The reliability was measured with Generalizability Theory and ranged between 0.81 and 0.93. CONCLUSIONS: The clinical competence of undergraduate medical interns is considered sufficient. The results also show the subjects that require educational interventions to improve clinical competence of students.

Reliability analysis of the objective structured clinical examination using generalizability theory.

BACKGROUND: The objective structured clinical examination (OSCE) is a widely used method for assessing clinical competence in health sciences education. Studies using this method have shown evidence of validity and reliability. There are no published studies of OSCE reliability measurement with generalizability theory (G-theory) in Latin America. The aims of this study were to assess the reliability of an OSCE in medical students using G-theory and explore its usefulness for quality improvement. METHODS: An observational cross-sectional study was conducted at National Autonomous University of Mexico (UNAM) Faculty of Medicine in Mexico City. A total of 278 fifth-year medical students were assessed with an 18-station OSCE in a summative end-of-career final examination. There were four exam versions. G-theory with a crossover random effects design was used to identify the main sources of variance. Examiners, standardized patients, and cases were considered as a single facet of analysis. RESULTS: The exam was applied to 278 medical students. The OSCE had a generalizability coefficient of 0.93. The major components of variance were stations, students, and residual error. The sites and the versions of the tests had minimum variance. CONCLUSIONS: Our study achieved a G coefficient similar to that found in other reports, which is acceptable for summative tests. G-theory allows the estimation of the magnitude of multiple sources of error and helps decision makers to determine the number of stations, test versions, and examiners needed to obtain reliable measurements.

Stability of unstimulated and stimulated whole saliva flow rates in children.

OBJECTIVE: To analyze the stability of the unstimulated saliva flow rate (USFR) and the stimulated saliva flow rate (SSFR) in children followed from age 7 to 12 years old. METHODS: Longitudinal study. Whole saliva samples were collected from school children (50 girls and 50 boys). Forty-four girls and 32 boys remained in this cohort for 6 years (dropout rate 24%). Variables that could influence USFR or SSFR patterns were analyzed in a repeated-measures manova. RESULTS: Over a 6-year follow-up, the children's USFR ranged from 0.41 to 0.46 mL/min in the initial and final observation, respectively, and showed no significant differences (P = 0.4455) during the follow-up. The children consistently belonged to one of three distinct SSFR groups (P < 0.0001). A repeated-measures manova model showed that USFR and SSFR were not associated with sex, body mass index, or indoor temperature during sampling. CONCLUSION: These results indicate that USFR and SSFR patterns were stable from 7 to 12 years old. This finding may be useful in oral health prevention or treatment and in the search for biomarkers in saliva for screening or diagnostic purposes.

A Water and Education Provision Intervention Modifies the Diet in Overweight Mexican Women in a Randomized Controlled Trial.

BACKGROUND: There is minimal information on the impact of replacing sugar-sweetened beverage (SSB) consumption with water on diet quality from randomized controlled trials. OBJECTIVE: We evaluated the effect of a water intake intervention on diet quality in overweight Mexican women. METHODS: Women with a body mass index ≥25 and <39, 18-45 y old, and a self-reported high intake of SSBs (≥250 kcal/d) were randomly allocated to either the water and education provision (WEP) group (n = 120) or the education provision (EP) only group (n = 120). Each group received monthly nutrition counseling, and the WEP group received biweekly water deliveries for 9 mo. Three 24-h recalls, anthropometry, and demographic information were collected at baseline, and 3, 6, and 9 mo. Energy, macronutrient, sugar, SSB, fruit and vegetable, salty snack, cake and cookie, and fast food intakes were assessed in study completers (n = 189) classified by intervention assignment and by actual water intake at every time point (low <1200 vs. high ≥1200 mL/d). RESULTS: The WEP group reported greater decreases in SSB intake than the EP group (from 20.9% to 10.3% of energy/d vs. from 20.1% to 17.8%). Thirty-eight percent of the EP group and 84.3% of the WEP group reported attaining a water intake ≥1200 mL/d. Reductions in energy intake and food groups were similar across intervention groups. However, the high actual water intake group reported greater increases vs. the lower intake group in intake of fruits and vegetables (117 vs. 47 g/d), as well as larger reductions in salty snacks (4.6 vs. 0.7 g/d) and cakes and cookies (31.7 vs. 14.7 g/d). CONCLUSIONS: Other than SSBs, improvements in food group intake did not differ by intervention group in overweight Mexican women. However, post hoc analyses suggested that achieving a high actual water intake was associated with additional beneficial changes in food group intake. This trial was registered at clinicaltrials.gov as NCT01245010.

Estímulos económicos, exigencias de trabajo y salud en académicos universitarios mexicanos / Economic stimulus, work requirements and health in Mexican university faculty

Establecer la asociación entre las principales exigencias de trabajo y los daños a la salud en académicos que tienen la opción de participar en los programas de estímulos económicos. Estudio transversal y observacional, participaron 192 académicos universitarios con base en un muestreo aleatorio estratificado. Se recabaron datos sociodemográficos, exigencias laborales, perfil de daños a la salud e implicaciones derivadas de la participación en los programas de becas. Se utilizó el JMP8 y se controlaron variables confusoras (edad, género y antigüedad) estableciendo un nivel de significancia de p<0.05. El 64% cuenta con algún tipo de estímulo económico. El perfil de daños a la salud se caracterizó por trastornos músculo-esqueléticos (42%). Las exigencias de trabajo más representativas fueron: laborar en días de descanso (86%), cubrir una cuota de trabajo (80%) y sobrecarga de trabajo (60%); éstas se asociaron significativamente con: lumbalgia, músculo-esqueléticos, túnel del carpo y disfonía. Prevalecen tasas elevadas de trastornos músculo-esqueléticos, lumbalgia y disfonía, entre 3 y 4 de cada 10 trabajadores. Las exigencias laborales para poder concursar en los estímulos económicos se asociaron más significativamente con los daños a la salud, que los propios estímulos como tal. Es necesario visibilizar estos resultados para prevenirlos y atenderlos en materia de salud de los trabajadores.

To examine the association between the main job demands and adverse health effects among Mexican university faculty who have the option of participating in economic stimulus programs. Cross-sectional, observational study, involving a stratified random sample of 192 university academics. Data were collected on sociodemographics, job demands, adverse health profile implications arising from participation in economic incentive programs. The JMP8 was used and the analysis controlled for confounding variables (age, gender and age); statistical significance level was set at p < 0.05. Sixty-four percent of respondents indicated being eligible for some type of economic stimulus. The adverse health profile was characterized by musculoskeletal disorders (42%). The most representative job demands were working on days off (86%), covering for others (80%) and increased workload (60%). These factors were significantly associated with low back pain, musculoskeletal, carpal tunnel syndrome and dysphonia. The prevailing high rates of musculoskeletal disorders, back pain and dysphonia, affected between 3 and 4 out of 10 workers. Job demands required to participate in the economic stimulus were more significantly associated with adverse health than the economic incentives themselves.

[Clinical competence evaluation using the Objective Structured Clinical Examination (OSCE) in medical internship at UNAM]. / Evaluación de la competencia clínica con el examen clínico objetivo estructurado en el internado médico de la Universidad Nacional Autónoma de México.

INTRODUCTION: The Objective Structured Clinical Examination (OSCE) is a widely used measurement tool to assess clinical competence in the health sciences. There is little published evidence of its use in Mexican medical schools. OBJECTIVE: To assess clinical competence in medical students with an OSCE, before and after the Medical Internship. METHODS: Prospective cohort study, pre- post-test research design. The assessed population was medical students at UNAM Faculty of Medicine in Mexico in their Internship year. The instrument was an 18-stations OSCE, three stations per academic area of the Internship curriculum. RESULTS: We assessed the clinical competence of 278 students in a pretest OSCE when starting the Internship year, and tested them 10 months later with an equivalent post-test OSCE. The sample of students was 30.4% of the total Internship population. Test reliability with Cronbach's alpha was 0.62 in the pre-test and 0.64 in the post-test. The global mean score in the pretest OSCE was 55.6 ± 6.6 and in the post-test 63.2 ± 5.7 (p < 0.001), with a Cohen's d of 1.2. CONCLUSIONS: The clinical competence of medical students measured with an OSCE is higher after the medical internship year. This difference suggests that the internship can influence the development of clinical competence in medical students.

Aflatoxin (B1 , B2 , G1 , and G2 ) contamination in rice of Mexico and Spain, from local sources or imported.

Rice is an important cereal but it is often contaminated with aflatoxins (AFs). The purpose of this study was to identify and quantify AF (B1 , B2 , G1 , and G2 ) in 67 rice samples cultivated in Mexico and Spain, and from imported crops collected in 2008 and 2009. The methodology was validated, the rice samples were concentrated and purified with immunoaffinity columns and were quantified by high-pressure liquid chromatography (HPLC). The average total AF (AFt) in the Spanish rice was 37.3 µg/kg, the range was from 1.6 to 1383 µg/kg, the most contaminated samples being from San Juan de Aznalfarache, Sevilla (AFt = 138.6 µg/kg), from Tortosa, Tarragona (AFt = 104.6 µg/kg), and Calasparra, Murcia (AFt = 103.9 µg/kg). The rice imported from France to Spain had AFt of 26.6 µg/kg and from Pakistan AFt of 18.4 µg/kg, showing less AF contamination than the local one. The rice which originated from Mexico contained (AFt = 16.9 µg/kg), and those imported from the United States (AFt = 14.4 µg/kg) and Uruguay (AFt = 15.6 µg/kg). The imported rice had better quality in terms of the presence of AFs.

Interacciones tempranas madre-niño y predicción de desarrollo motor mediante ecuaciones estructurales: Aplicación del modelo en niños con riesgo de daño neurológico perinatal / Mother-child interactions and early motor development prediction using structural equation: Application of the model in children with perinatal risk of neurological damage

Los impactos más importantes de las expresiones tempranas del daño neurológico en los niños, son las dificultades para establecer intercambios con su medio social, afectando en la etapa inicial las primeras interacciones con su madre. Niños con riesgo biológico muestran grandes dificultades para iniciar interacciones. Cuando las madres se ajustan en una relación bidireccional se logra un aumento en las iniciaciones del niño; si las madres responden menos, los niños disminuyen las iniciaciones y aumentan la irritabilidad. Los programas de intervención temprana que integran en sus estrategias el manejo de las interacciones madre-niño se han considerado exitosos por sus implicaciones directas en el desarrollo del niño. Se requiere mayor soporte empírico sobre la influencia de patrones específicos de interacciones tempranas madre-hijo y el desarrollo posterior de niños con daño neurológico perinatal, en términos de prevención de alteraciones o discapacidad. Se realizó un estudio longitudinal y se reporta el efecto de las interacciones de reciprocidad madre-hijo en el desarrollo motor observado en niños a los 4, 8 y 12 meses de edad, a través del empleo del Modelo de Ecuaciones Estructurales (Curva de Crecimiento Latente). Se concluye que el modelo permitió mostrar que en niños de riesgo perinatal, las interacciones madre-hijo representan un buen predictor del desarrollo motor en el primer año de vida. Estos hallazgos tienen importantes implicaciones en la práctica clínica como estrategia integral para el diseño de acciones de intervención temprana debido a que los logros motores en los primeros meses representan un indicador predictivo del desarrollo infantil posterior.(AU)

The most important impact of early expressions of neurological damage in children is the difficulty of mixing up in their social environment which at the beginning affects their interactions with their mother. Children with biological risks show great difficulties to begin interactions. When mothers get adjusted to bidirectional relations with neurologically damaged children, an increase in the commencement of interactions by a child is achieved, while fewer responses of the mother to child produce fewer interactions and increases irritability. Early intervention programs which contain in their strategies management of mother-infant interactions have been considered effective for child development. However, further empirical studies are required, concerning the influence of specific patterns of early mother-infant interaction and future development of children with perinatal neurological damage, in terms of prevention of alterations or disability. The present longitudinal study reports the effect of reciprocity of mother-infant interactions in the motor development observed in children of 4, 8, and 12 months old, latent growth curve in structural equation modeling. This model permits the identifications of causal factors that could affect the results in different age groups and provides predictions of the relations in a more complex form than lineal relations. Based on the model designed, it could be shown that mother-infant interactions of reciprocity best characterized children with higher development level while the absence is seen in children with retarded development. We classified mothers and children in two types, respectively: interactive and organized mothers vs. non-interactive and disorganized ones; interactive and responsive children vs. non-interactive and non-responsive ones. Subjecting these two types of mothers and children to four possible combinations, the model results showed different motor development predictions in the children. On one hand, we estimated regression coefficient of four dyadic systems, obtained by combinations of different types of mothers and children: interactive and organized mother with interactive and responsive child (Dyadic system 1); interactive and organized mother with non-interactive and non-responsive child (Dyadic system 2); non-interactive and disorganized mother with interactive and responsive child (Dyadic system 3); and non-interactive and disorganized mother with non-interactive and non-responsive child (Dyadic system 4). Dyadic system 1 was associated with a better motor development in children with a mayor regression coefficient (19.82), followed by System 2 and System 3 (regression coefficient of 17.54 and 11.46, respectively). System 4 had a negative estimate value of regression coefficient (-11.27) in our model. On the other hand, we estimated intercept values according to the interactive type of these mothers and children. Among the four interactive types, solely two of them had statistically significant intercepts (p < .05), or = 66.13 for interactive children and or = 42.76, for non-interactive children. To predict the motor development of 4, 8, and 12 months old children, the slope with attenuation permitted to give a mayor model fitting, with the regression coefficient of 0, 1 and 1.5, respectively. This model presented excellent values of model fitting indicators (X² = .96, p = .97, CFI = 1.00, RMSEA = .00). This line of study should be widened, because motor development is the principal domain consolidated in the first months of life. It is fundamental in domain organizations of higher complexity as cognition and language. We conclude that this model showed that in high risk perinatal children, early mother-child interactions represent a good predictor of motor development in the first year of life. Moreover, we found that motor achievements in the first months of life can be a strong predictive indicator of future development of a child. These findings suggest the importance in clinical practice of observation and registration of mother-child interactions as part of an integral strategy of child evaluation.(AU)

Interacciones tempranas madre-niño y predicción de desarrollo motor mediante ecuaciones estructurales: Aplicación del modelo en niños con riesgo de daño neurológico perinatal / Mother-child interactions and early motor development prediction using structural equation: Application of the model in children with perinatal risk of neurological damage

Los impactos más importantes de las expresiones tempranas del daño neurológico en los niños, son las dificultades para establecer intercambios con su medio social, afectando en la etapa inicial las primeras interacciones con su madre. Niños con riesgo biológico muestran grandes dificultades para iniciar interacciones. Cuando las madres se ajustan en una relación bidireccional se logra un aumento en las iniciaciones del niño; si las madres responden menos, los niños disminuyen las iniciaciones y aumentan la irritabilidad. Los programas de intervención temprana que integran en sus estrategias el manejo de las interacciones madre-niño se han considerado exitosos por sus implicaciones directas en el desarrollo del niño. Se requiere mayor soporte empírico sobre la influencia de patrones específicos de interacciones tempranas madre-hijo y el desarrollo posterior de niños con daño neurológico perinatal, en términos de prevención de alteraciones o discapacidad. Se realizó un estudio longitudinal y se reporta el efecto de las interacciones de reciprocidad madre-hijo en el desarrollo motor observado en niños a los 4, 8 y 12 meses de edad, a través del empleo del Modelo de Ecuaciones Estructurales (Curva de Crecimiento Latente). Se concluye que el modelo permitió mostrar que en niños de riesgo perinatal, las interacciones madre-hijo representan un buen predictor del desarrollo motor en el primer año de vida. Estos hallazgos tienen importantes implicaciones en la práctica clínica como estrategia integral para el diseño de acciones de intervención temprana debido a que los logros motores en los primeros meses representan un indicador predictivo del desarrollo infantil posterior.

The most important impact of early expressions of neurological damage in children is the difficulty of mixing up in their social environment which at the beginning affects their interactions with their mother. Children with biological risks show great difficulties to begin interactions. When mothers get adjusted to bidirectional relations with neurologically damaged children, an increase in the commencement of interactions by a child is achieved, while fewer responses of the mother to child produce fewer interactions and increases irritability. Early intervention programs which contain in their strategies management of mother-infant interactions have been considered effective for child development. However, further empirical studies are required, concerning the influence of specific patterns of early mother-infant interaction and future development of children with perinatal neurological damage, in terms of prevention of alterations or disability. The present longitudinal study reports the effect of reciprocity of mother-infant interactions in the motor development observed in children of 4, 8, and 12 months old, latent growth curve in structural equation modeling. This model permits the identifications of causal factors that could affect the results in different age groups and provides predictions of the relations in a more complex form than lineal relations. Based on the model designed, it could be shown that mother-infant interactions of reciprocity best characterized children with higher development level while the absence is seen in children with retarded development. We classified mothers and children in two types, respectively: interactive and organized mothers vs. non-interactive and disorganized ones; interactive and responsive children vs. non-interactive and non-responsive ones. Subjecting these two types of mothers and children to four possible combinations, the model results showed different motor development predictions in the children. On one hand, we estimated regression coefficient of four dyadic systems, obtained by combinations of different types of mothers and children: interactive and organized mother with interactive and responsive child (Dyadic system 1); interactive and organized mother with non-interactive and non-responsive child (Dyadic system 2); non-interactive and disorganized mother with interactive and responsive child (Dyadic system 3); and non-interactive and disorganized mother with non-interactive and non-responsive child (Dyadic system 4). Dyadic system 1 was associated with a better motor development in children with a mayor regression coefficient (19.82), followed by System 2 and System 3 (regression coefficient of 17.54 and 11.46, respectively). System 4 had a negative estimate value of regression coefficient (-11.27) in our model. On the other hand, we estimated intercept values according to the interactive type of these mothers and children. Among the four interactive types, solely two of them had statistically significant intercepts (p < .05), or = 66.13 for interactive children and or = 42.76, for non-interactive children. To predict the motor development of 4, 8, and 12 months old children, the slope with attenuation permitted to give a mayor model fitting, with the regression coefficient of 0, 1 and 1.5, respectively. This model presented excellent values of model fitting indicators (X² = .96, p = .97, CFI = 1.00, RMSEA = .00). This line of study should be widened, because motor development is the principal domain consolidated in the first months of life. It is fundamental in domain organizations of higher complexity as cognition and language. We conclude that this model showed that in high risk perinatal children, early mother-child interactions represent a good predictor of motor development in the first year of life. Moreover, we found that motor achievements in the first months of life can be a strong predictive indicator of future development of a child. These findings suggest the importance in clinical practice of observation and registration of mother-child interactions as part of an integral strategy of child evaluation.

Tracheal dimensions in the Mexican population.

BACKGROUND: There are few studies regarding the measurement of tracheal dimensions. Most are focused on morphology and tracheal development. The aim of this study was to determine the length and tracheal diameter of adults in our population and its correlation with external measurements. METHODS: The study design was prospective, observational and descriptive. We included a nonrandom sampling of deaths of Mexican national citizens who were between 18 and 65 year old. The study period was from June 1 to November 30, 2009, and the study was carried out at the facilities of the Forensic Medical Service of the Federal District, Mexico. Standardized measurements of tracheal diameter and length were correlated with external measurements. RESULTS: We dissected 44 cadavers, 19 (43%) females and 25 (57%) males. In females the average age was 39.2 ± 13.9 years (range: 19-61 years), average height 161.9 ± 7.4 cm (range: 154-179 cm), tracheal length (TL) 8.6 ± 0.5 cm (range: 7.8-9.5 cm) and transverse diameter (TD) 1.7 ± 0.3 cm (range: 1.3-2.0 cm). Average age of males was 36.4 ± 14.4 years (range: 19-65 years), average height 169.8 ± 6.7 cm (range: 156-184 cm), TL 9.1 ± 0.9 cm (range: 8.0-10.7) and TD 1.9 ± 0.2 cm (range: 1.6-2.3 cm). TL was significantly correlated with sternal length (0.82, p <0.0001) and age (0.56, p = 0.0003). According to gender, there was no significant correlation between TL and height. CONCLUSIONS: We found a low average TL and no significant correlation with height. These data should be considered when carrying out direct procedures on the trachea.

El trabajo precario: origen de los daños a la salud en la industria de la construcción / Precarious work and adverse to health effects in the construction industry

Las nuevas formas de organización laboral provocan incertidumbre, precarización y violación de los derechos de los trabajadores. El obrero de la construcción es vulnerable porque tiene que aceptar condiciones de trabajo inhumanas para poder sobrevivir. Este estudio analiza la relación entre esas condiciones y los trastornos musculoesqueléticos, la fatiga y los accidentes. Se aplicó una encuesta validada en población trabajadora mexicana (n=128). Esta industria en México se caracteriza por pésimas condiciones de trabajo: la jornada es al menos de 12 horas, 99% de los trabajadores tiene contrato temporal y 77% no tiene ninguna prestación. Más de 75% está expuesto a múltiples riesgos que se asociaron con trastornos musculoesqueléticos de miembros superiores e inferiores (57,8%), lumbalgia (50%), fatiga crónica (48,4%) y accidentes de trabajo (44,5%). Las interacciones sinérgicas mostraron que la extensión y la intensidad de la jornada se encontraron fuertemente relacionadas con el esfuerzo físico intenso y las posiciones forzadas, para generar los diversos padecimientos.

New forms of work organization cause uncertainty and increased precariousness, and infringe on workers’ rights. Construction workers are vulnerable because they have to accept inhumane working conditions in order to survive. This study analyzes the relationship between these conditions and musculoskeletal disorders, fatigue and accidents. A previously validated survey was administered to a population of Mexcian workers (n=128). Conditions in the construction industry in Mexico are extremely poor: the work shifts are at least 12 hours long, 99% of workers work under temporary contracts, and 77% of workers receive no benefits. More than 75% are exposed to multiple hazards which were associated with musculoskeletal disorders of the limbs (57.8%), low back pain (50%), chronic fatigue (48.8%) and occupational injuries (44.5%). Synergistic interactions showed that the long duration and intensity of the working day were strongly related to intense physical activity and awkward positions in generating the various adverse health effects observed.

Noción de la palabra escrita y noción gramatical de la oración escrita en niños con antecedente de encefalopatía perinatal / Noção da palavra escrita e noção gramatical da oração escrita em criançascom antecedente de encefalopatia perinatal / The notion of the written word and the grammatical notion of the written sentence in children with a history of perinatal encephalopathy

El objetivo de esta investigación fue describir las características de la noción de la palabra escrita y la noción gramatical de la oración escrita, en 28 niños de 4 a 8 años con encefalopatías hipóxicoisquémica, hiperbilirrubinémica y mixta en el periodo perinatal. Para tal fin, se aplicaron las pruebas Monterrey y Terman Merrill, y se documentó la secuela neuropsicológica. El 75% de los niños presentó secuela cognoscitiva leve; 82% estuvo en el nivel esperado de las nociones evaluadas acordes con su edad, y del 18% de los niños con atraso en la lectura cuatro tuvieron antecedentes de encefalopatía mixta y uno antecedentes de hiperbilirrubinemia. Se discuten los niveles de conceptualización de lecto-escritura y su relación con variables biológicas y sociales.

The objective of this research project was to describe the notion of the written word and the grammatical notion of the written sentence in 28 children between the ages of 4 and 8, who suffered hypoxic ischemic, hyperbilirubinemic, or mixed encephalopathy during the perinatal period. For that purpose, the Monterrey and the Terman Merrill instruments were administered, and the neuropsychological sequelae were documented. 75% of the children showed slight cognitive sequelae; 82% were at the expected level for their age regarding the notions evaluated; and of the 18% of the children with reading delays, four had a history of mixed encephalopathy and one of hyperbilirubinemia. The study discusses the levels of conceptualization regarding reading and writing, and their relation to biological and social variables.

O objetivo desta investigação foi descrever as características da noção da palavra escrita e a noção gramatical da oração escrita, em 28 crianças de 4 a 8 anos com encefalopatias hipóxico-isquêmica, hiperbilirrubinêmica e mista no período perinatal. Com esta finalidade, aplicaram-se as provas Monterrey e Terman Merrill, e documentou-se a seqüela neuropsicológica. Apresentam seqüela cognoscitiva leve 75% das crianças; 82% estiveram no nível esperado das noções avaliadas de acordo com sua idade, e entre 18% das crianças com atraso na leitura, quatro têm antecedentes de encefalopatia mista e um antecedente de hiperbilirrubinemia. Discutem-se os níveis de conceitualização de lecto-escritura e sua relação com variáveis biológicas e sociais.

Polymorphisms associated with the risk of lung cancer in a healthy Mexican Mestizo population: Application of the additive model for cancer.

Lung cancer is the leading cause of cancer mortality in Mexico and worldwide. In the past decade, there has been an increase in the number of lung cancer cases in young people, which suggests an important role for genetic background in the etiology of this disease. In this study, we genetically characterized 16 polymorphisms in 12 low penetrance genes (AhR, CYP1A1, CYP2E1, EPHX1, GSTM1, GSTT1, GSTPI, XRCC1, ERCC2, MGMT, CCND1 and TP53) in 382 healthy Mexican Mestizos as the first step in elucidating the genetic structure of this population and identifying high risk individuals. All of the genotypes analyzed were in Hardy-Weinberg equilibrium, but different degrees of linkage were observed for polymorphisms in the CYP1A1 and EPHX1 genes. The genetic variability of this population was distributed in six clusters that were defined based on their genetic characteristics. The use of a polygenic model to assess the additive effect of low penetrance risk alleles identified combinations of risk genotypes that could be useful in predicting a predisposition to lung cancer. Estimation of the level of genetic susceptibility showed that the individual calculated risk value (iCRV) ranged from 1 to 16, with a higher iCRV indicating a greater genetic susceptibility to lung cancer.

Polymorphisms associated with the risk of lung cancer in a healthy Mexican Mestizo population: application of the additive model for cancer

Lung cancer is the leading cause of cancer mortality in Mexico and worldwide. In the past decade, there has been an increase in the number of lung cancer cases in young people, which suggests an important role for genetic background in the etiology of this disease. In this study, we genetically characterized 16 polymorphisms in 12 low penetrance genes (AhR, CYP1A1, CYP2E1, EPHX1, GSTM1, GSTT1, GSTPI, XRCC1, ERCC2, MGMT, CCND1 and TP53) in 382 healthy Mexican Mestizos as the first step in elucidating the genetic structure of this population and identifying high risk individuals. All of the genotypes analyzed were in Hardy-Weinberg equilibrium, but different degrees of linkage were observed for polymorphisms in the CYP1A1 and EPHX1 genes. The genetic variability of this population was distributed in six clusters that were defined based on their genetic characteristics. The use of a polygenic model to assess the additive effect of low penetrance risk alleles identified combinations of risk genotypes that could be useful in predicting a predisposition to lung cancer. Estimation of the level of genetic susceptibility showed that the individual calculated risk value (iCRV) ranged from 1 to 16, with a higher iCRV indicating a greater genetic susceptibility to lung cancer.

Motor response of 14-month-old female mice exposed to diazepam prenatally.

The response of adult female mice to diazepam (DZ) can be sculpted by the prenatal experience with the drug. Experiments were performed in ICR strain (Harlan México) mice exposed in utero to DZ. They were born from dams injected (s.c.) with 2.7 mg/kg/bw of DZ or just saline solution from day 6 to 17 of pregnancy. They were maintained at 12:12 dark/light cycles with food and water ad libitum. On the experimental day, mice were introduced in an activity meter (actometer) for 5 min. Recordings were run at 25 mm/min. The time they remained motionless or clearly sleepy was determined in millimeters. After that, all animals received (s.c.) 2.7 mg/kg/bw of DZ; 15 min later they were introduced into the actometer again for 5 min. Before DZ, control animals injected with saline during gestation showed 1.57 +/- 0.53 mm and the experimental (DZ) prenatally exposed to DZ, 3.69 +/- 1.72 mm (p =0.27). After DZ, control animals remained motionless for 37.27 +/- 6.77 mm and DZ mice, 59.95 +/- 7.10 mm (p=0.03). This result indicates a significantly larger response to DZ in the pretreated animals, suggesting that exposure of the developing fetus to the drug may lead to persistent (14 months) morphological alterations in several areas of the central nervous system with physiological repercussion on motor behavior and learning, sometimes attributed to brain circuitry modifications or to the developmental vulnerability of synaptic neurochemical mechanisms.

Testing a test: Analysis of the consistency of a pharmacology exam.

In higher education, learning variables are critical for professional activity and they should be properly assessed. Therefore, adequacy of evaluation instruments is very important. Consistency of an exam is one characteristic frequently studied to determine exam reliability. The subject of this study is a Pharmacology test of 70 items, taken by 849 medical students during a Pharmacology course at Medical School in the National University of Mexico in 2008. It explores whether students have been exposed to the same knowledge domain and if consistent execution in all parts of the exam is seen. Exam items were analyzed as independent items and as grouped items (by topic) and tested for consistency with Cronbach's test. Data were processed with the JMP statistical program (SAS Institute Inc.). The coefficient alpha was greater for independent items. We consider that grouping of items into topics tests integration of knowledge; a reasonable degree of consistency found when items are grouped, might favor this conclusion. Information obtained from the analysis of consistency of the exam, should provide elements for feedback during a course. Long term goals of this study include: to develop test instruments useful in formative evaluation and knowledge integration, to characterize the specificity of a Pharmacology exam, to determine degrees of knowledge acquisition and to get feedback about the quality of courses and exams.

Maternal dietary omega fatty acid intake and auditory brainstem-evoked potentials in Mexican infants born at term: cluster analysis.

OBJECTIVE: To identify biological and socioeconomic factors associated with the neurological development of Mexican infants born at term, as measured by brainstem auditory-evoked potentials (BAEPs). SUBJECTS AND METHODS: We conducted a cohort study among 76 women with low risk pregnancies recruited in their third trimester of pregnancy and followed their infants until 12 months of age. BAEP tests were conducted on the infants before 3 months of age during physiologic sleep, using 100 msec bipolar clicks. Maternal dietary intake was evaluated by food frequency questionnaire. Two BAEP groups (short latency, long latency) were identified by cluster analysis. The association between BAEP group and maternal PUFAs was estimated using logistic regression models adjusted for socioeconomic and biological factors. RESULTS: Short latency BAEPs were associated with a maternal diet rich in arachidonic acid (OR=3.63, 95% CI 1.23-10.67) after adjusting for age (in days) sex, head circumference and gestational age but was not significantly associated to a maternal diet rich in docosahexaenoic acid (DHA). CONCLUSIONS: Our results suggest the importance of arachidonic acid intake during pregnancy for short latency BAEPs and adequate fetal myelination.