Laser-Degeneration Study of Nerve Fibers in the Optic Nerve

Knowledge about wiring of neurons is one of the most important goals of neurobiology. Neuronal processes -axons and dendrites- degenerate when they are severed from their cell body. Since different staining procedures distinguish between the degenerating axons and their healthy neighbors, most neuroanatomical pathways have been mapped through the follow-up of degenerating axons after spontaneous or experimental lesions at some point of the pathway. Mapping of neuroanatomical connections has been enormously enriched during the past few years, thanks to new labelling techniques with great resolution power [1]. However, the resolution of the older degeneration procedures is only limited by the extent of the lesion and the resolution of the differential staining of degenerating axons. As we will show in this report, the use of a laser to produce small lesions in the retina of birds, coupled to the detection of degenerating axons in semi-thin plastic sections [2] is allowing us to understand the relationship between axons along the optic pathway with a resolution comparable to that of “in vivo” labelling techniques

Two distributions of axons in the optic nerve of quails: a study of nerve degeneraron after láser lesions of the retina

Order in the optic pathway has been under cióse scrutiny since the last century. In fishes, the position of the axons along the optic nerve is a function of the position or of the age of the corresponding neu- ronal body in the retina5’12’13. However, in cats, optic axons only show a crude retinotopic order8. Our observations in the quail showed the existence of at least two kinds of axons according to their position in the optic nerve. Although some axons were found in cióse spatial relationship with others originating in the same región of the retina, other axons occupied positions independent of their site of origin in the retina

Distribution of nerve fibers in the optic nerve of the quail: a laser-degeneration study

Normal visual function requires specific connections between the retina and the visual centers. Connections arise after migration of the optic axons to the brain; however, the biological basis of their specificity are mostly unknown. Som9 of the postulated mechanisms require a recognition between axons and brain neurons, whereas others depend on the maintenance of a retinotopic order along the optic pathways. (P&aacute;rrafo extra&iacute;do a modo de resumen)</em

Riesgo de anomalías congénitas en grupos étnicos de Sudamérica

El objetivo del trabajo fue estimar el riesgo de defectos congénitos según condición étnica de los padres del recién nacido. Fueron seleccionados 20.940 neonatos con 10 anomalías congénitas específicas y un grupo similar de controles, clasificados según su condición étnica. Se estimaron los riesgos de las 10 anomalías congénitas aisladas mediante métodos de regresión logística, ajustando los riesgos por índices de propensión (Propensity Score) utilizando la prueba de Mantel-Haenszel. Los resultados del presente trabajo mostraron que en europeos latinos existe un mayor riesgo de tener un recién nacido con espina bífida, sindactilia 2-3 del pie e hipospadias; en judíos el riesgo mayor es para hipospadias; en nativos para microtia, labio leporino, polidactilia preaxial y atresia anal; en afrodescendientes para polidactilia postaxial e hipospadias y en árabes para espina bífida. En conclusión, en Sudamérica algunos grupos étnicos muestran un riesgo incrementado para ciertas anomalías congénitas, independientemente de la edad de los padres, el nivel socioeconómico y el número de embarazos, sugiriendo susceptibilidad de ciertos grupos étnicos para determinados defectos congénitos.The objective of this study was to estimate the risk of congenital anomalies according to the ethnicity of the newborn’s parents. A sample of 20,940 newborns with 10 specific congenital anomalies was selected, together with a similar group of controls, and separated by ethnic group. The risks for the 10 isolated congenital anomalies were estimated by logistic regression methods, adjusting for Propensity Score using the Mantel-Haenszel test. The results of the present study showed that Latin Europeans have a high risk for spina bifida, syndactyly 2-3 of toes, and hypospadias; Jews for hypospadias; natives (Amerindian) for microtia, oral clefts, preaxial polydactyly and anal atresia; African descendants for postaxial polydactyly and hypospadias, and Arabs for spina bifida. In conclusion, inSouth America some ethnic groups have an increased risk for some congenital defects, which are not attributable to parental age, socioeconomic status or the number of pregnancies, suggesting that certain ethnic groups are more susceptible to specific birth defects

Determinantes sociales adversos y riesgo para anomalías congénitas seleccionadas

Introducción. Diferentes trabajos han relacionando condiciones sociales adversas a nivel familiar y regional con resultados perinatales (mortalidad neonatal, bajo peso y prematuridad); sin embargo, pocos estudiaron el efecto de la pobreza sobre anomalías congénitas. Objetivo. Evaluar el riesgo de ocurrencia de 25 anomalías congénitas y determinantes sociales adversos según el nivel socioeconómico de la familia y de la región. Población y métodos. Estudio caso-control exploratorio, en el que se utilizaron datos del Estudio Colaborativo Latinoamericano de Malformaciones Congénitas (ECLAMC). La muestra consistió en 3786 recién nacidos vivos con una única malformación y 13 344 controles, seleccionados entre 546 129 nacimientos, ocurridos en 39 hospitales de Argentina durante el período 1992-2001. Se estimaron los riesgos (OR) directos, indirectos (a través de la región de residencia) y la interacción entre el nivel socioeconómico individual y residencial para cada uno de los 25 defectos congénitos. Resultados. Los defectos labio leporino con/sin paladar hendido (OR= 1,43) y comunicación interventricular (OR= 1,38) mostraron un riesgo significativamente mayor en el nivel socioeconómico más bajo. Los niveles socioeconómicos bajos se asociaron de manera significativa con una mayor frecuencia de consanguinidad parental, ancestros nativos, edad materna menor de 19 años, más de 4 embarazos, bajo número de visitas prenatales y residencia en regiones desfavorables. Conclusión. La fisura labial con o sin paladar hendido y los defectos del tabique interventricular estuvieron asociados significativamente con un nivel socioeconómico más bajo. La falta de planificación familiar, de control prenatal y la exposición a agentes ambientales o teratógenos pueden explicar estos hallazgos.Introduction.Different studies have related familiar and regional adverse social conditions to perinatal outcome (neonatal mortality, low birth weight and prematurity); however, few studies have studied the effect of poverty on congenital anomalies. Objective.To assess the hazard ratio of 25 congenital anomalies and adverse social determinants as per the socioeconomic level of families and regions. Population and methods.Exploratory, casecontrol study using data from the Latin-American Collaborative Study of Congenital Malformations (Estudio Colaborativo Latinoamericano de Malformaciones Congénitas, ECLAMC). The sample consisted of 3786live newborn infants with a single malformation and 13 344 controls selected among 546 129 births occurred in 39hospitals from Argentina in the 1992- 2001 period. Both direct and indirect (residence) risks (OR) were estimated, together with the interaction between the individual and residential socioeconomic levels for each of the 25 congenital anomalies. Results.Cleft lip with/without cleft palate (OR= 1.43) and ventricular septal defect (OR= 1.38) showed a significantly higher risk in the lower socioeconomic level. Low socioeconomic levels were significantly associated with a higher frequency of parental sibship (blood relationship), native descent, maternal age younger than 19 years old, more than four pregnancies, a low number of antenatal care visits, and residence in deprived regions. Conclusion. Cleft lip with/without cleft palate and ventricular septal defects were significantly associated with a lower socioeconomic level. Lack of family planning and antenatal care, and exposure to environmental or teratogenic agents may account for these findings

Association of candidate gene polymorphisms with clinical subtypes of preterm birth in a Latin American population

Background. Preterm birth (PTB) is the leading cause of neonatal mortality and morbidity. PTB is often classified according to clinical presentation: Idiopathic (PTB-I), preterm premature rupture of membranes (PTB-PPROM), and medically induced (PTBM). The aim of this study was to evaluate the associations between specific candidate genes and clinical subtypes of PTB. Methods. 24 SNPs were genotyped in 18 candidate genes in 709 infant triads. Of them, 243 were PTB-I, 256 PTB-PPROM, and 210 PTB-M. These data were analyzed with a Family-Based Association. Results. PTB was nominally associated with rs2272365 in PON1, rs883319 in KCNN3, rs4458044 in CRHR1, and rs610277 in F3. Regarding clinical subtypes analysis, 3 SNPs were associated with PTB-I (rs2272365 in PON1, rs10178458 in COL4A3, and rs4458044 in CRHR1), rs610277 in F3 was associated with PTBPPROM, and rs883319 in KCNN3 and rs610277 in F3 were associated with PTB-M. Conclusions. Our study identified polymorphisms potentially associated with specific clinical subtypes of PTB in this Latin American population. These results could suggest a specific role of such genes in the mechanisms involved in each clinical subtype. Further studies are required to confirm our results and to determine the role of these genes in the pathophysiology of clinical subtypes

Informe de personal de apoyo: Campaña, Hebe Edith (2011-2012)

Proyectos de investigaci&oacute;n en los cuales colabora: a) Ambiente y riesgo para anomal&iacute;as cong&eacute;nitas b) Epidemiolog&iacute;a de defectos cong&eacute;nitos Anomal&iacute;as menores como predictoras de defectos mayores. Hendiduras orales y multigravidez Gastrosquisis y madre adolescente c) Resultados perinatales adversos en Am&eacute;rica del Sur d) Monitorizaci&oacute;n trimestral de defectos cong&eacute;nitos </div

Informe de personal de apoyo: Campaña, Hebe Edith (2013-2014)

Proyectos de investigaci&oacute;n en los cuales colabora: a) Ambiente y riesgo para defectos cong&eacute;nitos b) Epidemiolog&iacute;a de defectos cong&eacute;nitos c) Retinopat&iacute;a del prematuro e) Anomal&iacute;as cong&eacute;nitas en grupos &eacute;tnicos de Latinoam&eacute;ric

Informe de personal de apoyo: Campaña, Hebe Edith (2016-2017)

El Laboratorio de Epidemiología Genética de la Dirección de Investigación del Centro de Educación Médica e Investigaciones Clínicas (CEMIC) integra la coordinación del Estudio Latinoamericano de Malformaciones Congénitas, creado en el año 1967. Es un programa de investigación clínica y epidemiológica de anomalías congénitas y sus causas. El objetivo principal es la prevención primaria de los defectos congénitos mediante la investigación científica. En aproximadamente 100 hospitales, distribuidos en 42 ciudades, de diez países sudamericanos, todos los recién nacidos fueron diariamente examinados de acuerdo a idénticas normas operativas y los malformados diagnosticados fueron registrados y descriptos de acuerdo a un protocolo único. Más de seis millones de nacimientos han sido examinados por la red en los últimos casi 50 años. Esta base de datos con alrededor de 200.000 malformados constituye un material apto para el estudio de los factores genéticos y ambientales que interactúan en la compleja causalidad de las malformaciones

Informe de personal de apoyo: Campaña, Hebe Edith (2014-2015)

Exposici&oacute;n sint&eacute;tica de la labor desarrollada a. Ambiente y riesgo para defectos cong&eacute;nitos b. Epidemiolog&iacute;a de defectos cong&eacute;nitos. + Tasas de prevalencia de defectos cong&eacute;nitos + Gastrosquisis y madre adolescente + Aborto espont&aacute;neo y defectos cong&eacute;nitos c. Prematuro e. Anomal&iacute;as cong&eacute;nitas en grupos &eacute;tnicos de Latinoam&eacute;ric