"Oxidative stress induced by phthalates in mammals: State of the art and potential biomarkers".

BACKGROUND: Phthalates, plasticizers that are widely used in consumer products including toys, cosmetics, and food containers, have negative effects in liver, kidney, brain, lung and reproductive system of humans and other mammals. OBJECTIVES: To summarize, describe and discuss the available information on the effects of phthalate exposure in mammals, with emphasis on oxidative stress, and to suggest potential biomarkers of the health risks associated with phthalate exposure. METHODS: An assessment of scientific journals was performed using the PRISMA model for systematic reviews. Manuscripts reporting effects of phthalate exposure on mammalian health published in the last decade were selected according to originality, content, and association to health hazards. RESULTS AND DISCUSSION: We identified 25 peer-reviewed articles published between January 1st, 2010 and June 1st, 2021 that fit the aims and selection criteria. Phthalates induce oxidative stress and cell degenerative processes by increasing intracellular reactive species. Antioxidant cytoprotective systems decrease with time of exposure; conversely, oxidative damage markers, including thiobarbituric acid-reactive substances (TBARS), 8-hydroxy-2'-desoxyguanosine (8-OHdG) and malondialdehyde (MDA), increase. Phthalates were associated with endocrine system disfunction, metabolic disorders, infertility, nonviable pregnancy, cell degeneration, growth impairment, tumor development, and cognitive disorders. Phthalates can also aggravate health conditions such as asthma, hepatitis, diabetes, allergies, chronic liver and kidney diseases. Among humans, the more vulnerable subjects to phthalate exposure effects were children and individuals with a prior health condition. CONCLUSION: Chronic exposure to phthalates induces oxidative stress in mammals with concomitant adverse effects in reproductive, respiratory, endocrine, circulatory, and central nervous systems in both in vitro and in vivo trials. Oxidative damage markers and phthalate metabolites levels were the most common biomarkers of phthalate exposure effects. Studies in free-ranging and wild mammals are nil. Further studies on the pathways that lead to metabolic disruption are needed to identify potential treatments against phthalate-induced detrimental effects.

Fibropapillomatosis dynamics in green sea turtles Chelonia mydas over 15 years of monitoring in Akumal Bay, Quintana Roo, Mexico.

Fibropapillomatosis (FP) is a tumor disease that affects all sea turtle species but is mainly seen in green turtles Chelonia mydas. The pathology of FP has been described extensively, but its dynamics in populations over time have been less studied. We analyzed the dynamics of FP in a population of green turtles in Akumal Bay on the central coast of the Mexican Caribbean. A total of 475 green turtles were captured over 15 yr (2004-2018). The highest prevalence of FP was found in the largest turtles, and there was a positive relationship between FP prevalence and size of turtles. FP was first detected in 2008 at a prevalence of 1.6%, and annual prevalence increased markedly from 17.9% in 2015 to 54% by 2018. Likewise, severity of FP increased over time, with most turtles falling into moderately to severely diseased categories (tumor score 2). The average size of turtles with FP was significantly larger than the size of individuals without FP. Regression of tumors was seen in 21% of turtles, tumor score was higher in smaller individuals, and only tumor score 2 was present in the largest sea turtles. An increase in the prevalence and tumor score of FP coincided with the massive arrival of Sargassum in 2015, suggesting that altered environmental conditions may have played a role. The increased prevalence of FP in Akumal Bay prompts the need to explain what might be driving this phenomenon and how widespread it is in the Caribbean.

Ecological regime shift drives declining growth rates of sea turtles throughout the West Atlantic.

Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles-hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta-exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift (ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation (ENSO)-the strongest on record-combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures (SST) in the West Atlantic for years of declining growth rates (r = -.94) and the Multivariate ENSO Index (MEI) for all years (r = .74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study demonstrates the importance of region-wide collaborations.

Evidence of oxidative stress responses of green turtles (Chelonia mydas) to differential habitat conditions in the Mexican Caribbean.

Important foraging and nesting habitats for Caribbean green sea turtles (Chelonia mydas) exist within the Mesoamerican Reef System in the Mexican Caribbean. During the last 25 years, urban development and touristic activities have drastically increased in Quintana Roo, Mexico. Moreover, in the last decade, massive pelagic sargasso blooms have also afflicted this region; however, information about the biochemical responses of Caribbean green turtles to these inputs is absent. This study aimed to assess if the oxidative stress indicators in the red blood cells of green turtles are valuable biomarkers of the extent of the anthropic impact in this region. Persistent organic pollutants (POPs) were also measured in the plasma of free-living green turtles during 2015-2018 to characterize these habitats further. As biochemical biomarkers, the production rate of superoxide radical (O2•-), carbonylated protein content, and lipid peroxidation (TBARS) levels, and the activities of superoxide dismutase, glutathione S-transferase (GST), catalase, glutathione peroxidase were measured in erythrocytes. A 15 % occurrence of fibropapillomatosis (FP) was revealed, with tumor size being positively correlated with CAT activity in the affected individuals. A multivariate analysis embracing all oxidative stress markers discriminated green turtles between years of capture (p < 0.001), with those sampled during 2015 presenting the highest production of O2•- (p = 0.001), activities of GST (p < 0.001), levels of TBARS (p < 0.001) and carbonylated proteins (p = 0.02). These local and temporal biochemical responses coincided with the first massive Sargassum spp. bloom reported in the region. The results of this study corroborate the utility of the oxidative stress indicators as biomarkers of environmental conditions (sargasso blooms and POPs) in the green turtle as sentinel species.

Applying generalized linear models as an explanatory tool of sex steroids, thyroid hormones and their relationships with environmental and physiologic factors in immature East Pacific green sea turtles (Chelonia mydas).

Generalized linear models were fitted to evaluate the relationship between 17ß-estradiol (E2), testosterone (T) and thyroxine (T4) levels in immature East Pacific green sea turtles (Chelonia mydas) and their body condition, size, mass, blood biochemistry parameters, handling time, year, season and site of capture. According to external (tail size) and morphological (<77.3 straight carapace length) characteristics, 95% of the individuals were juveniles. Hormone levels, assessed on sea turtles subjected to a capture stress protocol, were <34.7nmolTL(-1), <532.3pmolE2 L(-1) and <43.8nmolT4L(-1). The statistical model explained biologically plausible metabolic relationships between hormone concentrations and blood biochemistry parameters (e.g. glucose, cholesterol) and the potential effect of environmental variables (season and study site). The variables handling time and year did not contribute significantly to explain hormone levels. Differences in sex steroids between season and study sites found by the models coincided with specific nutritional, physiological and body condition differences related to the specific habitat conditions. The models correctly predicted the median levels of the measured hormones in green sea turtles, which confirms the fitted model's utility. It is suggested that quantitative predictions could be possible when the model is tested with additional data.

Oxidative stress indicators and trace element concentrations in tissues of mako shark (Isurus oxyrinchus).

Liver, kidney and muscle from juvenile mako sharks (Isurus oxyrinchus) were collected in Baja California Sur. Lead (Pb), cadmium (Cd), mercury (Hg) and arsenic (As) concentrations were determined by atomic absorption spectrophotometry. The production of superoxide radical (O2(•-)) was measured as an indicator of reactive oxygen species production; lipid peroxidation (TBARS) and protein carbonyl levels were quantified as indicators of oxidative damage, and the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) was assessed as indicator of antioxidant defenses. Two discriminant functions separated muscle from liver and kidney samples. Cd concentration was lower in muscle than in kidney (p<0.05) and Hg concentration was higher in muscle than in liver and kidney (p<0.05). Although GR and SOD activities were higher, oxidative damage (TBARS and carbonyl protein levels) was also higher in kidney (p<0.05). SOD activity, TBARS levels, and Cd and Hg concentration were the set of predictors with significant relevance during tissue discrimination. Tissue metabolism, physiology of the organisms and environmental factors may be related to the differences in trace elements and oxidative stress indicators found in muscle, liver and kidney of the mako shark.

Description and quantification of micronucleus and nuclear abnormalities in erythrocytes of the sentinel green turtle (Chelonia mydas) with fluorescence microscopy.

Contamination in marine ecosystems is of the most critical threats to marine turtles. The identification of useful biomarkers to detect and monitor the physiological and clinical effects of pollutants on these populations will allow early detection of alterations (e.g., mutagenic damages) that could risk their viability or favor the development of diseases, thus threatening the biodiversity of these ecosystems and human population. This study is aimed at describing and quantifying nuclear anomalies in peripheral blood erythrocytes of green turtles (Chelonia mydas) from three distinct foraging areas in Mexico (Akumal, Xcalak, and Punta Herrero). We developed a novel morphological index that could be used as a biomarker to identify abnormal nuclei in peripheral blood erythrocytes. Here we describe for the first time in C. mydas, with a species-specific staining protocol, distinct nuclear abnormalities such as blebbed, lobed, notched, eight shape nuclei, and binucleated cells. These nuclear abnormalities were present in > 90 % of the subjects (n = 30). Moreover, 50 % of the organisms presented erythrocytes with micronuclei. The number of nuclear abnormalities did not correlate with size of the green turtles or differ between sites, or health status. We found a higher frequency of green turtles with nuclear abnormalities in the southern region (Punta Herrero and Xcalak) with the highest frequency of micronucleus and buds. The former could be associated to the constant exposure to chemical pollutants of oceanographic origin in the southern coast of Quintana Roo. Furthermore, the increasing anthropogenic pollution in Akumal could also explain the highest variability in the number of nuclear abnormalities presented in resident individuals. We propose that a long-term monitoring programs of green turtle populations in the Mexican Caribbean that include a micronucleus test could be a useful to determine possible mutagenic damage in these animals.

DEHP exposure impairs human skeletal muscle cell proliferation in primary culture conditions: preliminary study.

The plasticizer di (2-ethylhexyl) phthalate (DEHP) inhibits differentiation, impairs glucose metabolism, and decreases mitochondrial function in murine muscle satellite cells; however, if these effects are translated to human cells is unknown. The goal of this study was to evaluate changes in morphology and proliferation of primary human skeletal muscle cells exposed to DEHP. Rectus abdominis muscle samples were obtained from healthy women undergoing programed cesarean surgery. Skeletal muscle cells were isolated and grown under standard primary culture conditions, generating two independent sample groups of 25 subcultures each. Cells from the first group were exposed to 1 mM DEHP for 13 days and monitored for changes in cell morphology, satellite cell frequency and total cell abundance, while the second group remained untreated (control). Differences between treated and untreated groups were compared using generalized linear mixed models (GLMM). Cell membrane and nuclear envelope boundary alterations, loss of cell volume and presence of stress bodies were observed in DEHP-treated cultures. DEHP-treated cultures also showed a significant reduction in satellite cell frequency compared to controls. Exposure to DEHP reduced human skeletal muscle cell abundance. Statistical differences were found between the GLMM slopes, suggesting that exposure to DEHP reduced growth rate. These results suggest that exposure to DEHP inhibits human skeletal muscle cell proliferation, as evidenced by reduced cell abundance, potentially compromising long-term culture viability. Therefore, DEHP induces human skeletal muscle cell deterioration potentially inducing an inhibitory effect of myogenesis by depleting satellite cells.

Relation of dental wear to the concentrations of essential minerals in teeth of the California sea lion Zalophus californianus californianus.

Tooth wear in marine mammals has been attributed to age, feeding habits, behavior, and contaminants. Advanced tooth wear in some California sea lions, including some of very young age (<5 yr), in the Gulf of California, suggests that there are variations in chemical composition of tooth parts, wherein the concentrations of certain trace minerals might be anomalous, making them more susceptible to erosion. The concentrations of the essential minerals Ca, P, K, Na, Fe, Mg, and Zn in the dentition of Zalophus c. californianus are documented for the first time and are compared for sea lion teeth with different degrees of wear. Canine teeth and molars from 45 skulls collected at 15 localities since 1978 were digested in perchloric acid and analyzed using atomic adsorption spectrometry, the results being expressed in milligrams per 100 g. An index of tooth wear (Id) was established, involving the average wear on the teeth and the age of the organism. No significant difference was detected in the variables, but there was one between ages (p = 0.02). A higher degree of wear was observed up to 7 yr of age than from this age onward. Mineral concentrations did not explain the excessive wear observed (correlation, p > 0.09; ANOVA, p > 0.15); however, the Ca concentration of the teeth was inversely proportional to the age of the animal (sexes combined, p = 0.026) and particularly significant for the females (r2 = 0.112, r = -0.335, p = 0.039). Females could be more prone to decalcification because of their annual bone investment in their offspring. Animals of both sexes were susceptible to tooth wear as their age increased, but the higher frequency of animals between 4 and 7 yr suggests an impact on survival at early stages probably linked to deficient feeding and chronic malnutrition.

Oxidative damage to proteins related to metals and antioxidant defenses in breastmilk.

INTRODUCTION: Breast milk contains molecules needed for the development of children; the integrity and function of these molecules is affected by the presence of pro-oxidants. Protein carbonyls are mainly produced as a result of the interaction of metals with reactive oxygen species (ROS), which may initiate a chain reaction that promotes molecular oxidation. OBJECTIVE: This study aimed to determine the association between the concentration of protein carbonyls with the concentration of trace elements (lead [Pb], cadmium [Cd] and selenium [Se]), superoxide radical (O2•-) production, and glutathione (GSH) content, as well with the activity of the main antioxidant enzymes (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GPx], glutathione reductase [GR] and glutathione S-transferase [GST]) in breast milk. METHODS: In this study 108 transitional milk samples (7-10 days) were analyzed. Antioxidant enzyme activities, O2•-production, protein carbonyl and GSH concentrations were analyzed by spectrophotometry. Trace element concentration was quantified by atomic absorption spectrophotometry. Generalized linear modelling was used to assess the relationship between protein carbonyls concentration with oxidative stress indicators and trace elements concentration. RESULTS: Cd and Pb were detected in 21.3 and 55.6% of breast milk samples, respectively. The median concentration of Cd was 0.01 µg L-1 (0.01-3.52 µg L-1) and Pb concentration was 2.61 µg L-1 (0.08-195.20 µg L-1). According to the best-fit model, the main factors contributing to protein carbonyl concentrations were the activity of GPx, GR, and concentration of GSH, Se, Pb and Cd. CONCLUSIONS: According to the generalized linear model, the activity of GPx and GR, could help explain protein oxidation induced by Pb and Cd in breast milk.

Purine nucleoside phosphorylase and the enzymatic antioxidant defense system in breast milk from women with different levels of arsenic exposure.

Purine nucleoside phosphorylase (PNP) is an ubiquitous enzyme which plays an important role in arsenic (As) detoxification. As is a toxic metalloid present in air, soil and water; is abundant in the environment and is readily transferred along the trophic chain, being found even in human breast milk. Milk is the main nutrient source for the growth and development of neonates. Information on breast milk synthesis and its potential defense mechanism against As toxicity is scarce. In this study, PNP and antioxidant enzymes activities, as well as glutathione (GSH) and total arsenic (TAs) concentrations, were quantified in breast milk samples. PNP, superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR) activities and GSH concentration were determined spectrophotometrically; TAs concentration ([TAs]) was measured by atomic absorption spectrometry. Data suggest an increase in PNP activity (median = 0.034 U mg protein-1) in the presence of TAs (median = 1.16 g L(-1)). To explain the possible association of PNP activity in breast milk with the activity of the antioxidant enzymes as well as with GSH and TAs concentrations, generalized linear models were built. In the adjusted model, GPx and GR activities showed a statistically significant (p<0.01) association with PNP activity. These results may suggest that PNP activity increases in the presence of TAs as part of the detoxification mechanism in breast milk.

Purina nucleósido fosforilasa (PNP) es una enzima ubicua que desempeña un papel importante en la desintoxicación del arsénico (As). As es un metaloide tóxico presente en el aire, el suelo y el agua; es abundante en el medio ambiente y se transfiere fácilmente a lo largo de la cadena trófica, encontrándose incluso en la leche materna humana. Información sobre la síntesis de la leche materna y su potencial mecanismo de defensa contra tóxicos es escasa. En este estudio, se cuantificó la actividad de PNP y de las enzimas antioxidantes así como la concentración de glutatión (GSH) y de arsénico total ([TAs]) en muestras de leche materna. La actividad de PNP, superóxido dismutasa (SOD), catalasa (CAT), glutatión S-transferasa (GST), glutatión peroxidasa (GPx), glutatión reductasa (GR) y la concentración de GSH se determinaron por espectrofotometría; la [TAs] se midió por espectrometría de absorción atómica. Los datos sugieren un incremento en la actividad de PNP (mediana= 0.034 U mg proteína-1) con la presencia de TAs (mediana= 1.16 g L-1). Para explicar la posible asociación de la actividad de las enzimas antioxidantes y la concentración de GSH, así como [TAs], con la actividad de PNP en la leche materna, se construyeron modelos lineales generalizados. En el modelo ajustado, la actividad de GPx y GR presentó una asociación estadística (p.

Linking physiological approaches to marine vertebrate conservation: using sex steroid hormone determinations in demographic assessments.

Sex, age and sexual maturation are key biological parameters for aspects of life history and are fundamental information for assessing demographic changes and the reproductive viability and performance of natural populations under exploitation pressures or in response to environmental influences. Much of the information available on the reproductive condition, length at sexual maturity and sex determinations of endangered species has been derived from direct examination of the gonads in dead animals, either intentionally or incidentally caught, or from stranded individuals. However, morphological data, when used alone, do not provide accurate demographic information in sexually monomorphic marine vertebrate species (e.g. sharks, sea turtles, seabirds and cetaceans). Hormone determination is an accurate and non-destructive method that provides indirect information about sex, reproductive condition and sexual maturity of free-ranging individuals. Correlations between sex steroid concentrations and biochemical parameters, gonadal development and state, reproductive behaviour and secondary external features have been already demonstrated in many species. Different non-lethal approaches (e.g. surgical and mark-recapture procedures), with intrinsic advantages and disadvantages when applied on free-ranging organisms, have been proposed to asses sex, growth and reproductive condition. Hormone determination from blood samples will generate valuable additional demographic information needed for stock assessment and biological conservation.

Interaction between mercury (Hg), arsenic (As) and selenium (Se) affects the activity of glutathione S-transferase in breast milk; possible relationship with fish and sellfish intake.

Breast milk is regarded as an ideal source of nutrients for the growth and development of neonates, but it can also be a potential source of pollutants. Mothers can be exposed to different contaminants as a result of their lifestyle and environmental pollution. Mercury (Hg) and arsenic (As) could adversely affect the development of fetal and neonatal nervous system. Some fish and shellfish are rich in selenium (Se), an essential trace element that forms part of several enzymes related to the detoxification process, including glutathione S-transferase (GST). The goal of this study was to determine the interaction between Hg, As and Se and analyze its effect on the activity of GST in breast milk. Milk samples were collected from women between day 7 and 10 postpartum. The GST activity was determined spectrophotometrically; total Hg, As and Se concentrations were measured by atomic absorption spectrometry. To explain the possible association of Hg, As and Se concentrations with GST activity in breast milk, generalized linear models were constructed. The model explained 44% of the GST activity measured in breast milk. The GLM suggests that GST activity was positively correlated with Hg, As and Se concentrations. The activity of the enzyme was also explained by the frequency of consumption of marine fish and shellfish in the diet of the breastfeeding women.

La leche materna es considerada como una fuente ideal de nutrientes para el crecimiento y el desarrollo de los recién nacidos, pero también puede ser una fuente potencial de contaminantes. Las madres pueden estar expuestas a diversos contaminantes como resultado de su estilo de vida y de la contaminación ambiental. Mercurio (Hg) y arsénico (As) pueden afectar negativamente el desarrollo del sistema nervioso fetal y neonatal. Algunos peces y mariscos son ricos en selenio (Se), un oligoelemento esencial que forma parte de diversas enzimas relacionadas con el proceso de desintoxicación, incluyendo glutatión S-transferasa (GST). El objetivo de este estudio fue determinar la interacción entre Hg, As y Se, así como analizar su efecto sobre la actividad de GST en la leche materna. Muestras de leche materna fueron obtenidas entre los días 7 y 10 después del parto. La actividad de la GST fue determinada espectrofotométricamente. Las concentraciones totales de Hg, As y Se fueron medidas por espectrometría de absorción atómica. Para explicar la posible asociación de las concentraciones de Hg, As y Se con la actividad de la GST en la leche materna, se construyeron modelos lineales generalizados. El modelo explicó el 44% de la actividad de GST medida en leche materna. El MLG sugiere que la actividad de GST se correlacionó positivamente con las concentraciones de Hg, As y Se. La actividad de la enzima se explica también por la frecuencia de consumo de peces marinos y mariscos en la dieta de las mujeres que se encuentran en periodo de lactancia.

Marine diet and tobacco exposure affects mercury concentrations in pregnant women (I) from Baja California Sur, Mexico.

Seafood provides essential polyunsaturated fatty acids (PUFA) and other nutrients to pregnant women and their fetus(es) while a diet rich in finfish can be a major pathway of monomethyl mercury (MeHg+) exposure. We measured total mercury concentration ([THg]) in hair samples provided by 75 women in Baja California Sur (BCS) to assess its relationship with age, parity, tobacco smoke exposure, and diet based on survey methodologies. Generalized linear models (GLM) were used to explain the possible association of the different variables with [THg] in hair. Median [THg] in hair was 1.52 µgg-1, ranging from 0.12 to 24.19 µgg-1 and varied significantly by segment. Approximately 72% (54/75) of those evaluated exceed 1 µgg-1 [THg] and 8% (6/75) exceed 5 µgg-1 [THg] in hair. Although frequency of fish consumption contributed significantly to explaining hair [THg], fish consumption only explained 43% of [THg] in a GLM incorporating tobacco exposure and body mass index. This study establishes possible relationships among multiple potential sources of exposure and other factors related to [THg] in hair of women in the prenatal period. A more detailed examination of other sources of exposure and factors contributing to [THg] is warranted.

[Mercury concentration in breast milk of women from northwest Mexico; possible association with diet, tobacco and other maternal factors]. / Concentraciones de mercurio en leche de mujeres del noroeste de México; posible asociación a la dieta, tabaco y otros factores maternos.

OBJECTIVE: To determine THg levels in milk of women from Northwest Mexico and its potential association with maternal factors such as diet and tobacco smoke. METHOD: The study was performed in 108 milk samples donated by women in Baja California Sur. Data were stratified into three groups of 36 donors by number of pregnancies. General data, smoking, exposure to environmental tobacco smoke and seafood intake were explored. THg levels were measured using atomic absorption spectrophotometry. The difference between groups was evaluated with non-parametric statistics. To explain the possible association of the different variables with THg concentrations in milk, generalized linear models were performed. RESULTS: THg levels ranged from 1.23 µg/L in single-pregnancy women (GI) to 2.96 µg/L for women with 3 or more pregnancies (GIII) (p = 0.07). In the GI group THg concentration was 175% higher (p = 0.02) in women who do not eat fish, compared to those who eat fish. In the generalized linear model to adjust THg concentrations, the variables were: age, number of pregnancies, breastfeeding duration and exposure to tobacco smoke (p ≤ 0.05). CONCLUSIONS: Fish consumption was the factor that better adjusted models, relative to THg levels. The contribution associated to this factor was low; therefore, consumption of fish from the coast of Baja California Sur is safe. Tobacco increased Hg concentrations in breast milk; it is necessary to avoid the smoking habit during pregnancy and breast-feeding.

Objetivo: Determinar los niveles de mercurio total (THg) en leche de mujeres del Noroeste de México y su posible asociación con factores maternos, la dieta y el tabaco. Método: El estudio se realizó en leches donadas por 108 mujeres de Baja California Sur. Se estratificaron en tres grupos de 36 donantes según el número de gesta. Se exploraron datos generales, hábito tabáquico, exposición al humo de tabaco ambiental, ingesta de mariscos y pescados. Los niveles de THg fueron cuantificados utilizando espectrofotometría de absorción atómica. La diferencia entres grupos se evaluó con estadística no paramétrica. Para explicar la posible asociación de las diferentes variables estudiadas y las concentraciones de THg en la leche, se realizaron modelos lineales generalizados. Resultados: Los niveles de THg fueron desde 1.23 ?g/L en las primigestas (GI) a 2,96 ?g/L para las mujeres con 3 o más gestas (GIII) (p = 0,07). En el grupo de GI encontramos una concentración del THg 175% mayor (p = 0,02) entre las mujeres que no comen pescado, en comparación con las que si comen pescado. En el modelo lineal generalizado ajustado por las concentraciones de THg, las variables fueron: edad, número de embarazos, duración de la lactancia y exposición al tabaco (p =?0,05). Conclusiones: El consumo de pescado fue el factor que mejor ajustó los modelos en relación a los niveles de THg. El aporte de Hg por la dieta que se pudo asociar fue bajo, por lo que el consumo de pescado de las costas de Baja California Sur es seguro. El tabaco, incrementa las concentraciones de Hg en la leche materna, por lo que debe de limitarse su hábito durante el embarazo y la lactancia.

[Lipid peroxidation and the response of the antioxidant defense system in the obese type 2 diabetic compared with the non-obese type 2 diabetic]. / Peroxidación de lípidos y la respuesta del sistema de defensa antioxidante en el diabético tipo 2 obeso en comparación al diabético tipo 2 sin obesidad.

INTRODUCTION: Diabetes is associated with increased lipid peroxidation, quantified as the levels of thiobarbituric acid reactive substances (TBARS). In parallel, the antioxidant defense system (ADS) reacts to diminish the oxidative damage. OBJECTIVE: To determine the levels of lipid peroxidation and the activity of antioxidant enzymes in obese type 2 diabetic (DM2) individuals compared to non-obese DM2 individuals. METHODS: Lipid peroxidation was quantified by measuring TBARS and the ADS response by measuring the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). RESULTS: Two groups of 30 subjects were studied. The obese DM2 group had a mean body mass index (BMI) 38.6 ± 3.5 kg m(-2) compared to the control group 24.7 ± 3.6 kg m(-2) (p<0.01). TBARS levels in the study group were higher compared to the control group (p <0.01). Multiple linear regression analysis suggested that activities of SOD and CAT adjusted to lipid peroxidation (TBARS) in the obese DM2 individuals. CONCLUSION: TBARS levels suggest greater oxidative damage in obese DM2 subjects with a diminished response of ADS.

Introducción: La diabetes se asocia a un incremento en la peroxidación de lípidos, cuantificada a partir del nivel de sustancias reactivas al ácido tiobarbitúrico (TBARS). En paralelo, se activa el sistema de defensa antioxidante (SDA) para delimitar el daño. Objetivo: Determinar el grado de peroxidación de lípidos en individuos obesos diabéticos tipo 2 (DM2) y la respuesta del SDA en comparación con individuos con DM2 sin obesidad. Método: Se evaluó el daño a lípidos a través de la medición de las TBARS en dos grupos de 30 individuos. Se evaluó la respuesta del SDA por medio de la medición de la actividad de las enzimas catalasa (CAT), superóxido dismutasa (SOD) y glutatión peroxidasa (GPx). Resultados: El grupo de DM2 obesos presentó un índice de masa corporal (IMC) promedio de 38.6 ± 3.5 kg m-2 en comparación con el grupo control 24.7 ± 3.6 kg m-2 (p.

Oxidative damage to proteins related to metals and antioxidant defenses in breastmilk / Daño oxidativo a las proteínas relacionado con metales y defensas antioxidantes en la leche materna

Introduction: Breast milk contains molecules needed for the development of children; the integrity and function of these molecules is affected by the presence of pro-oxidants. Protein carbonyls are mainly produced as a result of the interaction of metals with reactive oxygen species (ROS), which may initiate a chain reaction that promotes molecular oxidation. Objective: This study aimed to determine the association between the concentration of protein carbonyls with the concentration of trace elements (lead [Pb], cadmium [Cd] and selenium [Se]), superoxide radical (O2 •-) production, and glutathione (GSH) content, as well with the activity of the main antioxidant enzymes (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GPx], glutathione reductase [GR] and glutathione S-transferase [GST]) in breast milk. Methods: In this study 108 transitional milk samples (7-10 days) were analyzed. Antioxidant enzyme activities, O2 •- production, protein carbonyl and GSH concentrations were analyzed by spectrophotometry. Trace element concentration was quantified by atomic absorption spectrophotometry. Generalized linear modelling was used to assess the relationship between protein carbonyls concentration with oxidative stress indicators and trace elements concentration. Results: Cd and Pb were detected in 21.3 and 55.6% of breast milk samples, respectively. The median concentration of Cd was 0.01 μg L-1 (0.01-3.52 μg L-1) and Pb concentration was 2.61 μg L-1 (0.08-195.20 μg L-1). According to the best-fi t model, the main factors contributing to protein carbonyl concentrations were the activity of GPx, GR, and concentration of GSH, Se, Pb and Cd. Conclusions: According to the generalized linear model, the activity of GPx and GR, could help explain protein oxidation induced by Pb and Cd in breast milk (AU)

Introducción: la leche materna contiene las moléculas necesarias para el desarrollo de los niños; la integridad y función de estas moléculas se afecta por la presencia de prooxidantes. Los carbonilos proteicos se producen principalmente como resultado de la interacción de metales con especies reactivas de oxígeno (ERO), los cuales pueden iniciar una reacción en cadena que promueve la oxidación molecular. Objetivo: este estudio tiene como objetivo determinar la asociación entre la concentración de carbonilos proteicos con la concentración de elementos traza (plomo [Pb], cadmio [Cd] y selenio [Se]), producción de radical superóxido (O2 •-), y contenido de glutatión (GSH), así como con la actividad de las principales enzimas (superóxido dismutasa [SOD], catalasa [CAT], glutatión peroxidasa [GPx], glutatión reductasa [GR] y glutatión S-transferasa [GST]) en leche materna. Métodos: en este estudio se analizaron 108 muestras de leche de transición (7-10 días). La actividad de las enzimas antioxidantes, producción de O2 •-, concentración de carbonilos proteicos y GSH se analizaron por espectrofotometría. La concentración de elementos traza se cuantificó por espectrometría de absorción atómica. Se utilizó un modelo lineal generalizado para evaluar la relación entre la concentración de carbonilos proteicos con los indicadores de estrés oxidativo y las concentraciones de elementos traza. Resultados: Cd y Pb fueron detectados en 21,3 y 55,6% de las muestras de leche materna, respectivamente. La mediana de la concentración de Cd fue 0,01 μg l-1 (0,01-3,52 μg l-1) y para la concentración de Pb fue 2,61 μg l-1 (0,08-195,20 μg l-1). De acuerdo con el modelo de mejor ajuste, los principales factores de afectan la concentración de carbonilos proteicos, son la actividad de GPx y GR, y las concentraciones de GSH, Se, Pb y Cd. Conclusiones: de acuerdo con el modelo lineal generalizado, la actividad de GPx y GR podría ayudar a explicar la oxidación proteica, inducida por Pb y Cd en leche materna (AU)

Oxidative stress indicators and chemical contaminants in East Pacific green turtles (Chelonia mydas) inhabiting two foraging coastal lagoons in the Baja California peninsula.

In order to determine the potential effects of contaminants in juveniles of East Pacific green turtle, Chelonia mydas, captured alive, circulating trace metal and organochlorine pesticide concentrations were correlated with body condition, antioxidant enzyme activities and lipid peroxidation levels. Turtles were sampled in Punta Abreojos (PAO) and Bahía Magdalena (BMA). Turtles from PAO showed higher silicon and cadmium concentrations, but lower α-hexachlorocyclohexane, γ-hexachlorocyclohexane, hexachlorobenzene and aldrin concentrations than individuals from BMA. In BMA cadmium concentration decreased as the standard carapace length of the turtles increased. In PAO concentrations of α-hexachlorocyclohexane, heptachlor and hexachlorobenzene were positively correlated with the weight of the individuals. Lipid peroxidation levels were positively correlated with cadmium concentrations. In turtles captured in PAO, enzymatic antioxidant activities correlated mostly with pesticide concentrations, while in individuals from BMA enzyme activities were correlated with trace element concentrations. Correlations between antioxidant enzyme activities and concentration of xenobiotics suggest physiological sensitivity of East Pacific green turtles to chemicals. Regional differences found could be influenced by habitat conditions such as currents, upwellings (PAO) and agricultural activities (BMA). We suggest that, combined, circulating contaminant concentrations, lipid peroxidation levels and antioxidant enzyme activities in sea turtles could be used as biomarkers of the habitat conditions.

[Not Available]. / Antioxidantes, especies reactivas de oxígeno y daño oxidativo asociado a la presencia de plaguicidas organoclorados en la leche materna.

Introducción: los plaguicidas organoclorados (POC) pueden incrementar la producción de especies reactivas de oxígeno (ERO). Tales efectos pueden ser contrarrestados por el sistema antioxidante, el cual se encuentra también en la leche materna. Objetivo: evaluar los indicadores de estrés oxidativo en leche materna asociados a la presencia de POC y su relación con la ingesta de alimentos marinos. Métodos: la leche materna fue colectada de 108 mujeres lactantes. Los indicadores de estrés oxidativo (actividad enzimática antioxidante, concentración de glutatión, producción de radical superóxido [O 2•- ], concentración de peroxidación de lípidos y carbonilos proteicos) se analizaron por espectrofotometría. Las concentraciones de POC se midieron por cromatografía de gases. Resultados y discusión: la producción de O 2•- no presentó relación significativa con las concentraciones de POC. Se encontraron correlaciones significativas entre las concentraciones de POC y la actividad de las enzimas antioxidantes (actividad de glutatión reductasa [GR] y concentración de aldrín [r = - 0,5], actividad de superóxido dismutasa [SOD] y concentración de α-HCH [r = 0,45]). El daño oxidativo mostró baja correlación con el contenido de POC (r < 0,30, p < 0,05). Es posible que los niveles de POC no sean suficientes para incrementar la producción de O 2•- , ya sea que el incremento en la producción de ERO se deba a especies reactivas diferentes a O 2•- o debido a que la capacidad antioxidante es suficiente para evitar el daño oxidativo en leche materna. Conclusión: los resultados de este estudio sugieren que la dieta marina no es un factor determinante en el nivel de contaminación por POC, ni en el daño oxidativo presente en leche materna.

Antioxidants, reactive oxygen species and oxidative damage associated to the presence of organochlorine pesticides in breast milk / Antioxidantes, especies reactivas de oxígeno y daño oxidativo asociado a la presencia de plaguicidas organoclorados en la leche materna

Introduction: Organochlorine pesticides (OCPs) can increase the production of reactive oxygen species (ROS), the effects of which can be countered by the antioxidant system, also present in breast milk. Objective: To evaluate the indicators of oxidative stress in breast milk associated to the presence of OCPs, and their relationship with seafood intake. Methods: Breast milk was collected from 108 lactating women. Indicators of oxidative stress (antioxidant enzyme activity, glutathione concentration, superoxide radical [O2 •-] production, lipid peroxidation and carbonylated protein concentration) were analyzed by spectrophotometry. OCPs concentrations were measured by gas chromatography. Results and discussion: O2 •- production had no significant relationship with OCPs concentrations. Significant correlations between OCPs concentrations and antioxidant enzyme activities (glutathione reductase [GR] activity and aldrin concentration [r = - 0.5], superoxide dismutase [SOD] activity and α-HCH concentration [r = 0.45]) were found. Oxidative damage had a low correlation with OCPs content (r < 0.30, p < 0.05). It is possible that OCP’s levels are not sufficient to increase O2 •- production, that production of ROS other than O2 •- is increased, or that the antioxidant capacity is sufficient to avoid oxidative damage in breast milk. Conclusion: Results from this study suggest that marine diet is not a determinant factor in the level of contamination by OCP’s or in the oxidative damage in breast milk (AU)

Introducción: los plaguicidas organoclorados (POC) pueden incrementar la producción de especies reactivas de oxígeno (ERO). Tales efectos pueden ser contrarrestados por el sistema antioxidante, el cual se encuentra también en la leche materna. Objetivo: evaluar los indicadores de estrés oxidativo en leche materna asociados a la presencia de POC y su relación con la ingesta de alimentos marinos. Métodos: la leche materna fue colectada de 108 mujeres lactantes. Los indicadores de estrés oxidativo (actividad enzimática antioxidante, concentración de glutatión, producción de radical superóxido [O2 •-], concentración de peroxidación de lípidos y carbonilos proteicos) se analizaron por espectrofotometría. Las concentraciones de POC se midieron por cromatografía de gases. Resultados y discusión: la producción de O2 •- no presentó relación significativa con las concentraciones de POC. Se encontraron correlaciones significativas entre las concentraciones de POC y la actividad de las enzimas antioxidantes (actividad de glutatión reductasa [GR] y concentración de aldrín [r = - 0,5], actividad de superóxido dismutasa [SOD] y concentración de α-HCH [r = 0,45]). El daño oxidativo mostró baja correlación con el contenido de POC (r < 0,30, p < 0,05). Es posible que los niveles de POC no sean suficientes para incrementar la producción de O2 •-, ya sea que el incremento en la producción de ERO se deba a especies reactivas diferentes a O2 •- o debido a que la capacidad antioxidante es suficiente para evitar el daño oxidativo en leche materna. Conclusión: los resultados de este estudio sugieren que la dieta marina no es un factor determinante en el nivel de contaminación por POC, ni en el daño oxidativo presente en leche materna (AU)