Chromosomal effects of infections in malnourished and eutrophic children of Gran La Plata

The aim of this study was to assess the induction of structural chromosomal aberrations in peripheral blood lymphocytes of malnourished and eutrophic children with bacterial infections. Thirty-six infants concurrent to the Hospital Interzonal de Agudos y Crónicos Dr. Alejandro Korn, La Plata, Argentina were included in this analysis; 11 infected and malnourished (IM), 7 infected and eutrophic (IE) and 18 non-infected and eutrophic (NE). Children aged 1-60 months. Anthropometric and clinic evaluation were performed to assess nutritional condition. We scored structural chromosome aberrations (SCA) in 100 metaphases per individual. Statistical analysis was performed by the Epi Dat 3.0 (OPS-OMS, 2003), through «Test de Diferencias entre dos proporciones muestrales» (p<0.05). Total SCE frequency was five times higher in IM children than that of IE ones (15,1% vs. 3,33% p<0,001) and two times greater in IE than in NE children (3,33% vs. 1,88% p<0.05). Results presented here showed an increase frequency of SCA not only in relation with malnutrition but also with the presence of bacterial infections. It is difficult to discern whether structural chromosome aberrations are due to malnutrition per se, bacterial or viral infections, antibiotics or all of these factors acting on malnourished tissues. In conclusion, mutagenic factors cause chromosomal changes more easily in an altered environment.Instituto de Genética VeterinariaFacultad de Ciencias Naturales y Muse

Chromosomal effects of infections in malnourished and eutrophic children of Gran La Plata

The aim of this study was to assess the induction of structural chromosomal aberrations in peripheral blood lymphocytes of malnourished and eutrophic children with bacterial infections. Thirty-six infants concurrent to the Hospital Interzonal de Agudos y Crónicos Dr. Alejandro Korn, La Plata, Argentina were included in this analysis; 11 infected and malnourished (IM), 7 infected and eutrophic (IE) and 18 non-infected and eutrophic (NE). Children aged 1-60 months. Anthropometric and clinic evaluation were performed to assess nutritional condition. We scored structural chromosome aberrations (SCA) in 100 metaphases per individual. Statistical analysis was performed by the Epi Dat 3.0 (OPS-OMS, 2003), through «Test de Diferencias entre dos proporciones muestrales» (p<0.05). Total SCE frequency was five times higher in IM children than that of IE ones (15,1% vs. 3,33% p<0,001) and two times greater in IE than in NE children (3,33% vs. 1,88% p<0.05). Results presented here showed an increase frequency of SCA not only in relation with malnutrition but also with the presence of bacterial infections. It is difficult to discern whether structural chromosome aberrations are due to malnutrition per se, bacterial or viral infections, antibiotics or all of these factors acting on malnourished tissues. In conclusion, mutagenic factors cause chromosomal changes more easily in an altered environment.Instituto de Genética VeterinariaFacultad de Ciencias Naturales y Muse

Possible radioprotective effect of folic acid supplementation on low dose ionizing radiation-induced genomic instability <i>in vitro</i>

Ionizing radiation (IR) induces DNA damage through production of single and double-strand breaks and reactive oxygen species (ROS). Folic acid (FA) prevents radiation-induced DNA damage by modification of DNA synthesis and/or repair and as a radical scavenger. We hypothesized that in vitro supplementation with FA will decrease the sensitivity of cells to genetic damage induced by low dose of ionizing radiation. Annexin V, comet and micronucleus assays were performed in cultured CHO cells. After 7 days of pre-treatment with 0, 100, 200 or 300 nM FA, cultures were exposed to radiation (100 mSv). Two un-irradiated controls were executed (0 and 100 nM FA). Data were statistically analyzed with X2-test and linear regression analysis (P in vitro; folate status should be taken into account when studying the effect of low dose radiation in environmental or occupational exposure.Facultad de Ciencias VeterinariasFacultad de Ciencias Naturales y MuseoInstituto de Genética Veterinari

Possible radioprotective effect of folic acid supplementation on low dose ionizing radiation-induced genomic instability <i>in vitro</i>

Ionizing radiation (IR) induces DNA damage through production of single and double-strand breaks and reactive oxygen species (ROS). Folic acid (FA) prevents radiation-induced DNA damage by modification of DNA synthesis and/or repair and as a radical scavenger. We hypothesized that in vitro supplementation with FA will decrease the sensitivity of cells to genetic damage induced by low dose of ionizing radiation. Annexin V, comet and micronucleus assays were performed in cultured CHO cells. After 7 days of pre-treatment with 0, 100, 200 or 300 nM FA, cultures were exposed to radiation (100 mSv). Two un-irradiated controls were executed (0 and 100 nM FA). Data were statistically analyzed with X2-test and linear regression analysis (P in vitro; folate status should be taken into account when studying the effect of low dose radiation in environmental or occupational exposure.Facultad de Ciencias VeterinariasFacultad de Ciencias Naturales y MuseoInstituto de Genética Veterinari

Variations in estimates of underweight, stunting, wasting, overweight and obesity in children from Argentina comparing three growth charts

Objective: To compare estimates of underweight, stunting, wasting, overweight and obesity based on three growth charts. Design Cross-sectional study to estimate weight-for-age, length/height-for-age and weight-for-height comparing the 2006 WHO Child Growth Standards ('the WHO standards'), the 1977 National Center for Health Statistics (NCHS) international growth reference ('the NCHS reference') and the 1987 Argentine Pediatric Society Committee of Growth and Development reference ('the APS reference'). Cut-off points were defined as mean values ±2 s d. Epi-Info software version 6·0 (Centers for Disease Control and Prevention) was used for statistical evaluations (χ 2, P ≤ 0·05). Setting Greater La Plata conurbation, Buenos Aires, Argentina. Subjects A total of 2644 healthy, full-term children from 0 to 5 years of age. Results Prevalence of underweight was higher with the WHO standards than with the other references up to the first 6 months. For the rest of the ages, prevalence was lower with the WHO standards. Stunting prevalence was higher with the WHO standards at all ages. Prevalence of wasting was higher with the WHO standards compared with the NCHS reference up to the first 6 months and lower at 2-5 years of age. Overweight and obesity prevalences were higher with the WHO standards at all ages. Conclusions The new WHO standards appear to be a solid and reliable tool for diagnosis and treatment of nutritional diseases, also being the only one built with infants fed according to WHO recommendations. Therefore, our results support the decision of the National Ministry of Health about the utilization of the new WHO standards to monitor the nutritional status of Argentinean children aged less than 5 years.Instituto de Genética Veterinari

Possible radioprotective effect of folic acid supplementation on low dose ionizing radiation-induced genomic instability <i>in vitro</i>

Ionizing radiation (IR) induces DNA damage through production of single and double-strand breaks and reactive oxygen species (ROS). Folic acid (FA) prevents radiation-induced DNA damage by modification of DNA synthesis and/or repair and as a radical scavenger. We hypothesized that in vitro supplementation with FA will decrease the sensitivity of cells to genetic damage induced by low dose of ionizing radiation. Annexin V, comet and micronucleus assays were performed in cultured CHO cells. After 7 days of pre-treatment with 0, 100, 200 or 300 nM FA, cultures were exposed to radiation (100 mSv). Two un-irradiated controls were executed (0 and 100 nM FA). Data were statistically analyzed with X2-test and linear regression analysis (P in vitro; folate status should be taken into account when studying the effect of low dose radiation in environmental or occupational exposure.Facultad de Ciencias VeterinariasFacultad de Ciencias Naturales y MuseoInstituto de Genética Veterinari

In vitro approach to the study of chronic exposure to low doses of x-rays

El presente trabajo fue realizado con el fin de estudiar el efecto de dosis bajas y repetidas de radiación sobre dos líneas celulares de la misma especie. Se desarrolló un modelo in vitro para evitar la influencia de los factores de confusión que afectan a los estudios epidemiológicos y para simular una exposición crónica. Las técnicas utilizadas fueron el ensayo cometa y el análisis de apoptosis temprana; estas se llevaron a cabo inmediatamente después de la exposición y luego de la irradiación crónica. La irradiación secuencial indujo un aumento de células con daño en el ADN. El índice de daño fue mayor que el de los controles en ambas líneas celulares, tanto inmediatamente después de la exposición como luego de la irradiación crónica. Este aumento fue estadísticamente significativo solamente para la línea celular transformada luego de la irradiación crónica (p<0,001). El análisis de apoptosis arrojó niveles significativamente mayores al control para ambas líneas celulares luego de la exposición crónica (p<0.001). Se demostró que la exposición crónica a radiación ionizante de dosis bajas indujo daño en el ADN y apoptosis en células de hámster chino cultivadas in vitro. Las respuestas de ambos tipos celulares fueron algo diferentes. Evidentemente, el tipo celular debe ser tenido en cuenta a la hora de diseñar experimentos in vitro para entender los efectos de la radiación crónica de dosis baja en las poblaciones celulares.The present research was undertaken in order to study the effect of repeated low doses of radiation on two different cell lines from the same species. An in vitro model test was developed to avoid the influence of the confounding factors affecting epidemiological studies and to simulate a chronic exposure (50 mSv of x-rays during ten consecutive days). Comet assay and early apoptosis were analyzed immediately after exposure and after chronic irradiation. Sequential irradiation induced an increase of cells showing DNA damage. Index Damage was higher than that of the controls in both cell lines immediately after exposure and after chronic irradiation; these differences between exposed and control cells were statistically significant only for the transformed cell line after chronic irradiation (p<0.001). Significantly higher levels of apoptosis were scored after chronic exposure in both cells lines (p<0.001). The induction of DNA damage and apoptosis in hamster cells by chronic exposure to low dose ionizing radiation was demonstrated. Cell types reacted differently to chronic exposure; though further investigation is needed to understand the mechanisms of radiation effects on chronic low-dose-exposed cell populations, cellular type should be taken into account in the design of in vitro experiments to understand low-dose-irradiation effects.Instituto de Genética Veterinari

Mechanisms involved in the induction of aneuploidy: The significance of chromosome loss

The induction of aneuploidy by physical and chemical agents using different test systems was evaluated. The effect of X-rays, caffeine, acetaldehyde, ethanol, diethylstilbestrol, propionaldehyde, and chloral hydrate was studied by chromosome counting in Chinese hamster embryonic diploid cells. Aneugenic ability of cadmium chloride, cadmium sulfate, potassium dichromate, chromium chloride, nickel chloride, and nickel sulfate was assessed by means of anaphase-telophase analysis in Chinese hamster ovary cells. Chromosome counting in human fibroblasts (MRC-5 cell line) was employed to evaluate the effect of cacodilic acid, cadmium chloride, cadmium sulfate, and potassium dichromate. Finally, the induction of kinetochore-positive and kinetochore negative micronuclei by cadmium chloride, cadmium sulfate, potassium dichromate, chromium chloride, and nickel chloride was studied using CREST antibodies. When the effect of different agents was determined by chromosome counting, an increase of hypoploid but not of hyperploid cells was observed. Anaphase-telophase analysis showed that metal salts increased the frequency of lagging chromosomes. This finding has been confirmed by the increment of kinetochore-positive micronuclei using CREST antibodies. Therefore, chromosome loss could be considered as the main cause of induced aneuploidy.Facultad de Ciencias VeterinariasInstituto de Genética Veterinari

In vitro approach to the study of chronic exposure to low doses of x-rays

El presente trabajo fue realizado con el fin de estudiar el efecto de dosis bajas y repetidas de radiación sobre dos líneas celulares de la misma especie. Se desarrolló un modelo in vitro para evitar la influencia de los factores de confusión que afectan a los estudios epidemiológicos y para simular una exposición crónica. Las técnicas utilizadas fueron el ensayo cometa y el análisis de apoptosis temprana; estas se llevaron a cabo inmediatamente después de la exposición y luego de la irradiación crónica. La irradiación secuencial indujo un aumento de células con daño en el ADN. El índice de daño fue mayor que el de los controles en ambas líneas celulares, tanto inmediatamente después de la exposición como luego de la irradiación crónica. Este aumento fue estadísticamente significativo solamente para la línea celular transformada luego de la irradiación crónica (p<0,001). El análisis de apoptosis arrojó niveles significativamente mayores al control para ambas líneas celulares luego de la exposición crónica (p<0.001). Se demostró que la exposición crónica a radiación ionizante de dosis bajas indujo daño en el ADN y apoptosis en células de hámster chino cultivadas in vitro. Las respuestas de ambos tipos celulares fueron algo diferentes. Evidentemente, el tipo celular debe ser tenido en cuenta a la hora de diseñar experimentos in vitro para entender los efectos de la radiación crónica de dosis baja en las poblaciones celulares.The present research was undertaken in order to study the effect of repeated low doses of radiation on two different cell lines from the same species. An in vitro model test was developed to avoid the influence of the confounding factors affecting epidemiological studies and to simulate a chronic exposure (50 mSv of x-rays during ten consecutive days). Comet assay and early apoptosis were analyzed immediately after exposure and after chronic irradiation. Sequential irradiation induced an increase of cells showing DNA damage. Index Damage was higher than that of the controls in both cell lines immediately after exposure and after chronic irradiation; these differences between exposed and control cells were statistically significant only for the transformed cell line after chronic irradiation (p<0.001). Significantly higher levels of apoptosis were scored after chronic exposure in both cells lines (p<0.001). The induction of DNA damage and apoptosis in hamster cells by chronic exposure to low dose ionizing radiation was demonstrated. Cell types reacted differently to chronic exposure; though further investigation is needed to understand the mechanisms of radiation effects on chronic low-dose-exposed cell populations, cellular type should be taken into account in the design of in vitro experiments to understand low-dose-irradiation effects.Instituto de Genética Veterinari

Aneuploidy induction by heavy metals: evaluation using cytogenetic technics in mammalian cells

Entre las alteraciones que puede sufrir el complemento cromosómico de una especie, la aneuploidía (pérdida o ganancia de uno o varios cromosomas) reviste particular importancia por su relación etiológica con abortos espontáneos, malformaciones congénitas y transformación neoplásica. Sin embargo, no existen pruebas para la identificación de agentes aneugénicos (capaces de inducir aneuploidía) que hayan sido convalidados a nivel internacional mediante ensayos coordinados entre varios laboratorios. El presente trabajo analiza las diversas pruebas que han sido propuestos en años recientes y desarrolla el análisis crítico de uno de ellos-el de anafase-telofase- describiendo experimentos llevados a cabo con sales de metales pesados. Así, se evidencia que la prueba tiene suficiente sensibilidad como para diferenciar efectos de sustancias que, si bien poseen un modo de acción semejante, no actúan de la misma manera sobre el material genético. Por ejemplo, el cadmio (II) y el cromo (VI) fueron aneugénicos y clastogénicos mientras que el níquel (II) fue sólo aneugénico. Lo mismo puede decirse con respecto a la citotoxicidad ya que en la prueba se pudieron discriminar los efectos de las diferentes sales en función de su velocidad de ingreso a las células y de las reacciones involucradas en la formación de reactivos intermedios. Además, en todos los casos se pudieron establecer claras relaciones dosis-respuesta. Finalmente, dada su sencillez y bajo costo en términos de infraestructura necesaria y tiempo de análisis, el test puede ser recomendable para el abordaje inicial del estudio de sustancias de sospechada genotoxicidad.Among the alterations that can be induced in the chromosome complement of any specie the aneuploidy (loss or gain of one or more chromosomes) has a high relevance due to its ethiological relation with spontaneous abortus, congenital malformations and neoplastic transformation. Nevertheless, the tests proposed to identify aneugenic agents (agents able to induce aneuploidy) had no been convalidated internationally through interlaboratory coordinate assays. This work analyze the different tests proposed in recent years and develop a critical analysis of one of them -the anaphase- telophase test- describing the experiments carried out with heavy metal salts. Results obtained showed that the test has sensitivity enough to differentiate the effects of compounds that, having similar mechanisms of action do not act in the same way on the genetic material. For example, whereas cadmium (II) and chromium (VI) were aneugenics and clastogenics, nickel (II) was only aneugenic. Similarly, this test discriminated the different cytotoxic effects of the heavy metal salts in relation with the different uptake of each one by the cells and the reactions involved in the formation of reactive intermediates. Moreover, in all the cases it was possible to clearly establish dose-response relationships. Finally, due to its simplicity and low cost in terms of the necessary infrastructure and time consuming, the test can be recommended for the primary screening of suspected genotoxicants.Facultad de Ciencias Veterinaria