Pesticide exposure and its effects on intrauterine and postnatal development / Exposición a plaguicidas y sus efectos en el desarrollo intrauterino y posnatal

Abstract Background: The period between conception and the first two postnatal years is critical and marks the individual, largely determining their health and disease patterns. Objective: To review the effect of pesticide exposure in utero and in the 1st years of life. Materials and methods: The scientific literature in relation to the subject was reviewed, both in animal models and in humans. Results: The presence of various types of pesticides in umbilical cord blood and in meconium is well documented in newborns worldwide, including Mexico. Pesticides have been associated with low birth weight, and various birth defects at the heart, gastrointestinal tract, genitourinary system, musculoskeletal system, and neurodevelopmental disorders. These substances may play a role in the increase in cases of autistic disorder. Conclusions: Despite the evidence, there are no public policies in many countries, including Mexico, to control the sale and use of pesticides. It is required to prevent exposure to these substances in the population and to do follow-up studies in mother-child pairs where exposure is suspected.

Resumen Introducción: El periodo comprendido entre la concepción y los primeros dos años posnatales es crítico y marca al individuo, determinando en buena parte sus patrones de salud y enfermedad. Objetivo: Hacer una revisión sobre el efecto de la exposición a plaguicidas en útero y en los primeros años de vida. Material y métodos: Se revisó la literatura científica en relación con el tema, tanto en modelos animales como en humanos. Resultados: La presencia de diversos tipos de plaguicidas en la sangre de cordón umbilical y en meconio está bien documentada en recién nacidos en todo el mundo, incluyendo México. Los plaguicidas se han asociado con bajo peso al nacer y diversos defectos congénitos a nivel cardiaco, del tracto gastrointestinal, sistema genitourinario y sistema musculoesquelético, así como a trastornos en el desarrollo neurológico. Estas sustancias pueden tener participación en el incremento de casos de trastorno autista. Conclusiones: A pesar de las evidencias, no existen en muchos países, incluyendo México, políticas públicas para controlar la venta y uso de plaguicidas. Se requiere prevenir la exposición a estas substancias en la población y hacer estudios de seguimiento en binomios madre-hijo donde se sospeche exposición.

Treatment with lamivudine and entecavir in severe acute hepatitis B.

Background: Severe acute hepatitis B (SAHB) is an insufficiently described clinical entity, with relatively scarce data on anti-viral therapy available in field literature. Methods: We performed an open-label study to evaluate specific antiviral therapy in SAHB in Bucharest, Romania, during 2005–2009. Patients were allocated to two treatment groups and one control group: Group 1 – lamivudine 100 mg/day, Group 2 – entecavir 0.5 mg/day and Group 3 – standard of care, without anti-viral therapy. The primary endpoint was hepatitis B surface antigen (HBsAg) to hepatitis B surface antibody (anti-HBs) seroconversion by 24 weeks. Additional analyses included assessment of HBsAg clearance and hepatitis B e antigen (HBeAg) to hepatitis B e antibody (anti-HBe) seroconversion. Results: In Group 1, 7/69 patients (10.14%, P = 0.032) reached HBsAg/Ab seroconversion by 24 weeks, compared with 9/21 (42.85%, P = 0.053) in Group 2 and 25/110 (22.72%) in Group 3. HBsAg clearance by 24 weeks: 16/69 patients (23.18%, P = 0.027) in Group 1, 11/21 (52.38%, P = 0.256) in Group 2 and 43/110 (39.09%) in Group 3. HBeAg/Ab seroconversion: 46/61 (75.40%, P = 0.399) in Group 1, 9/19 (47.36%, P = 0.001) in Group 2 and 74/100 (74.00%) in Group 3. Conclusion: Anti-viral therapy can be considered for managing selected cases of SAHB. Biochemical as well as virological parameters need to orient the choice of the anti-viral agent. Lamivudine displayed a greater decrease in viral load compared to controls, but it was associated with lower levels of HBsAg to anti-HBs seroconversion. Patients treated with entecavir showed a better response in terms of HBs seroconversion by 24 weeks.

Optical Magnification Should Be Mandatory for Microsurgery: Scientific Basis and Clinical Data Contributing to Quality Assurance

BACKGROUND: Microsurgical techniques are considered standard procedures in reconstructive surgery. Although microsurgery by itself is defined as surgery aided by optical magnification, there are no guidelines for determining in which clinical situations a microscope or loupe should be used. Therefore, we conducted standardized experiments to objectively assess the impact of optical magnification in microsurgery. METHODS: Sixteen participants of microsurgical training courses had to complete 2 sets of experiments. Each set had to be performed with an unaided eye, surgical loupes, and a regular operating microscope. The first set of experiments included coaptation of a chicken femoral nerve, and the second set consisted of anastomosing porcine coronary arteries. Evaluation of the sutured nerves and vessels were performed by 2 experienced microsurgeons using an operating microscope. RESULTS: The 16 participants of the study completed all of the experiments. The nerve coaptation and vascular anastomoses exercises showed a direct relationship of error frequency and lower optical magnification, meaning that the highest number of microsurgical errors occurred with the unaided eye. For nerve coaptation, there was a strong relationship (P<0.05) between the number of mistakes and magnification, and this relationship was very strong (P<0.01) for vascular anastomoses. CONCLUSIONS: We were able to prove that microsurgical success is directly related to optical magnification. The human eye's ability to discriminate potentially important anatomical structures is limited, which might be detrimental for clinical results. Although not legally mandatory, surgeries such as reparative surgery after hand trauma should be conducted with magnifying devices for achieving optimal patient outcomes.

Measurement of psychosocial health in medical students: Validation of the Jefferson Medical College's Questionnaire in Mexico

The greater the psychosocial health, the greater is the well-being and the capacity for adaptation and overcoming problems and common life frustrations in family, relationships, and work. Medical students and practicing physicians, in comparison with the general population and that of other professions, are exposed to academic and professional stress and therefore are vulnerable to psychosocial health problems and certain specific dysfunctions that may compromise their physical, mental, and social health. In the field of psychosocial research in medical education, the key issue is to find relevant and psychometrically sound measures. The Jefferson Medical College's Psychosocial Questionnaire contains abridged versions of nine personality tests, as well as questions about respondents' relationships with parents in the first five years of life and with classmates in the early schooling. The scales in the questionnaire have shown satisfactory internal consistency reliability and construct validity through factor analysis. To our knowledge, in Mexico, there is not a specific questionnaire that measures psychosocial profile in a non-clinical population such as medical students. The present study adapted and translated the questionnaire from English to Spanish in order to evaluate its validity and reliability in Mexican medical students, to further learn its predictive validity of academic performance. In this study, we compared the factor structure in Mexico to the results obtained in the United States research. Implications for predicting academic and clinical performance of medical students and physicians were discussed. Study participants consisted of 3,603 matriculates at the Escuela de Medicina de la Universidad Autónoma de Nuevo León (Mexico). Psychosocial measures included Loneliness, Test anxiety, General anxiety, Self-esteem, Extroversion, External locus of control, Neuroticism, Depression, Stressful life events, Perceptions of early relationships with mother and father, Peer relationships and Perception of health, used by researchers at Jefferson Medical College in the United States. The items were translated into Spanish and back translated from Spanish to English, following the guidelines for adaptation of instruments for psychological evaluation. The questionnaire was administered in the third month after admission of the students to the Medicine School in the students' usual classrooms, on a schedule and day set aside for it according to the school's administration program. They were assured of the strict confidentiality of the test scores and of the individual data. Dimensionality of 40 items of the eight brief psychosocial scales was assessed with factor analysis using the principal components extraction method and orthogonal rotation; the Depression Scale was not included in the factorial analysis because it was not shortened for the present study. Correlation coefficients and internal consistencies were calculated for all the scales. Unidimensionality and construct validity were confirmed for measures of Loneliness, Test anxiety, General anxiety, Self-esteem, and Extroversion. The pattern and direction of the scale correlations with external criterion measures supported the concurrent validity of some of the measures. Also, the magnitude and direction of the inter-scale correlations supported the convergent and discriminant validities with the exception of the External locus of control and Neuroticism scales. The results supported the psychometric properties of the scales useful for providing information for medical educators and mental health professionals in early detection of psychosocial problems. It is important to mention that in spite of frequent talk about the importance of health among college students, few schools of Medicine in Mexico and in Latin America actually promote empirical research and support detect problems and develop solutions once they are identified. The mental health professionals should be responsible for sharing their understanding. They are capable of helping faculty for optimizing mental health through allocation of educational and remedial resources when designing academic programs in agreement with necessities of their students.

Como la literatura consigna, los estudiantes y profesionales de la Medicina en comparación con la población general y de otras carreras conforman una población que resulta vulnerable frente a los trastornos de salud psicosocial. En la investigación psicosocial de la educación médica un punto clave corresponde a la identificación de medidas relevantes con cualidades psicométricas. En el presente trabajo se analiza la validez y confiabilidad de un conjunto de escalas psicosociales aplicadas a 3.603 alumnos de la Facultad de Medicina de la Universidad Autónoma de Nuevo León (México). Las escalas administradas fueron: Soledad, Ansiedad ante los exámenes, Ansiedad general, Autoestima, Extroversión, Locus de control externo, Neuroticismo, Depresión, Eventos estresantes en la vida, Percepción de relaciones tempranas con los padres y amigos y Percepción de estado de salud general. Estas escalas fueron propuestas por investigadores de la Escuela de Medicina de Jefferson (Estados Unidos). Se confirmó la unidimensionalidad y la validez de constructo de las mediciones de Soledad, Ansiedad ante los exámenes, Ansiedad general, Autoestima y Extroversión. Así también, la magnitud y dirección de las correlaciones interescalas apoyaron la validez convergente y discriminante, con excepción de Locus de control externo y Neuroticismo. Los resultados confirman las propiedades psicométricas de las escalas, las cuales son útiles para proveer información a los educadores médicos y a profesionales de la salud mental en la detección temprana de problemas psicosociales quienes en conjunto pueden coadyuvar en la optimización de la salud mental de los estudiantes de escuelas de Medicina a través de programas académicos acordes a sus necesidades.

Caracterización de antígenos de bajo peso molecular de angiostrongylus costaricensis, reconocidos durante una infección experimental en roedores / Characterization of low molecular weight antigens of angiostrongylus costaricensis recognized during an experimental infection in mice

La respuesta inmune hacia componentes de bajo peso molecular del antígeno somático de A. costaricensis fue investigada en el modelo animal experimental. Durante la fase crónica de la infección y mediante el Western blot, son detectados por la IgG e IgG1 tres antígenos inmunodominantes: uno de 20 otro de 15 y uno de 2 kDa respectivamente. Mediante el método de digestión de Edmann se obtuvo la secuencia de aminoácidos inicial de cada componente: para la banda de 15 kDa una secuencia con un 100 por ciento de homología con la enzima glutation-S-transferasa de Brugia malayi y Onchocerca volvulus, para el componete de 2kDa una secuencia con 95 por ciento de homología con la proteína Ubiquitina, y para el compontente de 20 kDa una secuencia de trece aminoácidos, que no presenta homología con alguna proteína hasta ahora descrita. En general la reacción cruzada contra estos componentes es muy débil y en el caso particular del componente de 20 kDa no se detecta ninguna reacción cruzada. Se proponen futuros estudios con sueros humanos, para verificar la utilidad de dichos antígenos en el desarrollo de una prueba diagnóstica específica para la angiostrongiliosis abdominal.

Impact of early surgical correction of curves in paralytic scoliosis

The purpose of this investigation was to investigate the advantages of early surgery in patients suffering from neuromuscular scoliosis. Between January 1992 and January 1998, 20 patients with paralytic scoliosis, with an average age of 15 years, were treated surgically in the Department of Orthopedic Surgery, University Hospital, Feiburg, Germany. The parameter investigations included correction of the scoliosis independent of preoperative curves, operation time independent of Cobb angles, complications and blood loss. Surgery included a dorsal semi rigid instrumentation with pedicle screws in the lumbo-sacral region and sublaminar wiring in the thoracic area. The preoperative scoliotic curve measured 73.1°, the postoperative curve 24.5°, the mean correction was 66.4%. The thoracic kyphosis could be corrected from 13.9-25.7°. The operation time was longer and the correction was less if high Cobb angles were found preoperatively. Two wound infections were observed. Rod breakage following a pseudarthrosis occurred in one patient, a refusion was necessary. Cobb angles alone should not be the standard to indicate surgery in neuromuscular scoliosis. If a decreased functional ability, pelvic obliquity or trunk decompensation with reduced vital capacity are found, surgery is more dangerous while the obtained correction is less. Therefore, we recommend early surgery

Treatment of tuberculous spondylitis at the cervicothoracic junction. Clinical impact of surgery by means of sternotomy

The operative treatment of tuberculous spondylitis remains a challenge with regard to the surgical approach to the cervicothoracic junction. In addition, it is difficult to restore the resected vertebral bodies. Two cases of tuberculous spondylitis in this area are presented. The first case concerns a 25-year-old African patient suffering from the effects of tuberculous spondylitis: Destruction of vertebral bodies dorsal [D]1, D2, and D3, kyphosis coupled with compression of the spinal cord, as well as incomplete motor and sensory paraplegia [Frankel grade C]. The operative treatment of tuberculous spondylitis that is described, approached the cervicothoracic junction by means of a sternotomia. Corpectomy of vertebral bodies D1 through D3 were followed by their restoration with the help of a titanium cage. As a result, the paraplegia disappeared. Ventral decompression was followed by dorsal instrumentation. The results of the operation are decompression of the spinal cord, correction of the kyphosis, and stable fusion followed by restitution of the paraplegia. Primary stability was provided by the use of a titanium cage and dorsal instrumentation. There was no need for an external brace. There was no loss of correction 3 years after the operation. The 2nd case concerns a 49-year-old European patient suffering from thoracic pain radiating around the chest. A partial destruction of D2 and D3 with kyphosis and compression of the spinal cord because of a tuberculous spondylitis were detected, neurological deficits were not found. The corpectomy of D2 and D3 were proceeded by means of a sternotomy, the defect was restored with the help of a titanium cage. Due to the use of a ventral Morscher plate an additional dorsal instrumentation was not necessary. The patient was fixed in a minerva plaster for 3 months. There was no loss of correction 2 years after the operation. Both patients are manual workers and postoperatively adapted to their former work

Carry-over of persistent organochlorine pesticides through placenta to fetus

Objetivo. Como consecuencia de la exposición ambien-tal a los plaguicidas organoclorados éstos se acumulan en tejidos ricos en grasa, como el adiposo materno, y se distribu-yen en el suero materno y el suero del cordón umbilical. Para establecer la distribución en el organismo humano, se comparó el gradiente de concentración de los plaguicidas organoclorados entre estos compartimentos. Material y métodos. Se tomaron las muestras de tejido adiposo materno, suero materno y suero del cordón umbilical de 64 participantes voluntarias admitidas para cesárea en el Hospital Benito Coquet Lagunes, de la ciudad de Veracruz, Veracruz, México, durante el periodo 1997-1998. Los residuos de plaguicidas se determinaron por cromatografía de gases y sus resultados se correlacionaron entre las muestras por medio del coeficiente de correlación de Pearson y regresión lineal simple. Resultados. Los resultados más significativos expresados en base lipídica indican que las concentracio-nes del DDT fueron más altas en el tejido adiposo mater-no (4.51 mg/kg DDE y 1.27 mg/kg pp'DDT), suero materno (4.45 mg/kg DDE y 0.78 mg/kg pp'DDT) y suero del cordón umbilical (4.70 mg/kg DDE y 0.88 mg/kg pp'DDT), debido a su mayor afinidad a los lípidos. Conclusiones. La evaluación estadística de los resultados y el pareado entre las muestras indican que los plaguicidas organoclorados absorbidos atra-viesan la barrera placentaria y forman un equilibrio entre el organismo materno y el feto.