Selenium status in term neonates, according to birth weight and gestational age, in relation to maternal hypertensive pathology.

Background: Pregnancy represents a state of increased oxidative stress and antioxidants, in which selenium (Se) plays a pivotal role, contribute to maintain the oxidative balance. If antioxidant defenses are depleted, placental function is disrupted, resulting in pregnancy complications, including pregnancy-induced hypertension (PIH). Little is known about fetal selenium status in concomitant relation to maternal PIH, gestational age (GA) and birthweight (BW). Methods: We examined over a 3-year period the serum (SeS) and urine selenium (SeU) status in term neonates from normotensive (nonPIH) and hypertensive (PIH) mothers as clinical markers of oxidative stress. In this retrospective observational study, 72 neonates with maternal PIH were matched for GA and BW to 72 neonates of normotensive mothers. Four groups were obtained, based on maternal PIH and BW relative to GA (appropriate-for-gestational-age-AGA, small-for-gestational-age-SGA): nonPIH-AGA (control group), nonPIH-SGA, PIH-AGA, and PIH-SGA. Results: The results showed significant differences (p < 0.001) in selenium levels among the study groups: SeS - 44.85 ± 7.56 µg/L in nonPIH-AGA, 39.62 ± 11.42 µg/L in nonPIH-SGA, 40.01 ± 10.07 µg/L in PIH-AGA, and 25.39 ± 8.99 µg/L in PIH-SGA; SeU - 27.98 ± 7.99 µg/L in nonPIH-AGA, 22.85 ± 9.48 µg/L in nonPIH-SGA, 23.44 ± 6.73 µg/L in PIH-AGA, and 13.05 ± 5.86 µg/L in PIH-SGA. Selenium depletion was more common in neonates born from hypertensive mothers and those born small for gestational age. Though moderate in intensity, selenium levels were positively correlated with BW (0.319 for SeS, 0.397 for SeU) and negatively correlated with maternal systolic blood pressure (-0.313 for SeS, -0.324 for SeU). The main independent effects on SeS and SeU of each maternal blood pressure and birth weight turned out statistically significant. In interaction, a more pronounced effect was reached in PIH-SGA neonates. Conclusion: Selenium status seemed to reflect the negative impact that PIH exerts in neonates during intrauterine development. Clinical markers of selenium status could thus be of great value for tracking responses of individuals to selenium supplementation as part of health improvement and harm mitigation approaches.

Evaluation of Serum Selenium Status by Age and Gender: A Retrospective Observational Cohort Study in Western Romania.

Selenium, residing in a series of selenoproteins, plays an important role in both female and male reproductive function. Of particular significance for reproduction is the antioxidant glutathione peroxidase (GPx), a main selenoenzyme, whose level is regulated by the availability of Se in the body. We hypothesized that changes in Se status, closely related to GPx activity, would result in an increased risk of reproductive dysfunction in individuals. We retrospectively investigated the serum selenium (SeS) concentrations of 1264 apparently healthy people, aged 16-89 years, from Western Romania. The general analysis revealed a non-normal SeS distribution with a median SeS of 100.26 ± 18.32 µg/L and a significant difference in SeS levels between age groups. The analysis of the young group (16-35 years) revealed that up to 50% of individuals did not reach the SeS threshold corresponding to maximum GPx activity (80 µg/L), and a significant imbalance between the genders was apparent when looking at SeS values outside the range. Our results correlated with the general diminished reproductive ability registered in Romania during the last few years. Serum selenium content proves to offer a proper reflection of the fertility competence of the young population, and its monitoring is important for guiding dietary adjustments and attaining normal reproductive function.

The Link Between Selenium, Oxidative Stress and Pregnancy Induced Hypertensive Disorders.

BACKGROUND: The first line of defence against oxidative stress (OS) are the endogenous antioxidants, such as the Se containing compounds. During pregnancy, OS is caused by the intense growth activity of the fetus; therefore, the placenta is a key place for the activity of many seleno-compounds such as glutathione-peroxidase and thioredoxinreductase. METHODS: This review aims to establish the link between the type of selenium compounds, their concentration, their metabolic pathways, and their role in both physiologic and pathologic processes during pregnancy. RESULTS: A review of current literature establishes that Se containing compounds have a strong antioxidant effect. The limits that define deviations from the normal concentration range of selenium are very close. Both selenium deficiency and excess have an effect on human health. It is well known that oxidative stress, namely the increase in the concentration of reactive species of oxygen and nitrogen (ROS and RNS) and the disruption of cellular redox homeostasis, are responsible for a number of inflammatory, degenerative, autoimmune, and neoplastic diseases. Selenium deficiency in the pregnant woman's body is considered a risk factor for immune deficiency, PIH, spontaneous abortions, and premature birth. In regard to the fetus, while there seems to be a certain protection against selenium-induced toxicity, studies have shown that selenium defficiency leads to IUGR and SGA newborns. Also, combined deficiency of selenium and iodine has been linked to endemic cretinism in newborns. CONCLUSIONS: The antioxidant role that selenium performs through selenoproteins is major. Selenium-containing proteins, especially glutathione peroxidase, as antioxidant enzymes, are involved in regulating the ROS and RNS levels and redox balancing in almost all tissues. Among the multiple benefits of selenium in optimal concentrations in the body are stimulation and support of female fertility, as well as good development of the fetus. Hypertensive pathologies that occur in one of ten pregnant women, especially during the second part of the gestation period, are largely due to selenium deficiency.

Spectrophotometric Determination of Selenium Through Triiodide Anion.

BACKGROUND: Selenium is a chemical element found in the human body that plays a crucial role in its regulation. Depending on the concentration, it may have beneficial or have toxic effects. Selenium is incorporated as selenocysteine amino acid residue in selenoproteins which play an important role in many biological functions: anti-oxidant defense, regulation of the immune function and of the inflammatory response, metabolism of thyroid hormones, functioning of the central nervous system, biosynthesis of DNA and RNA, fertility, and reproduction. Excess selenium, altough less common than selenium deficiency, has equally important negative effects. METHODS: Given the importance of selenium quantification in various samples, the study proposes a simple and direct spectrophotometric determination of selenium using triiodide anions. The method is based on the oxidation of iodide in acidic medium by selenium (IV) contained in the sample, to form elemental iodine which, in turn, reacts with the excess iodide to form the triiodide anions, the most stable soluble species in aqueous solution. Triiodide is colored from yellow to brown, depending on the concentration. The coloured compound has maximum absorbance at specific wavelengths and thus, the stage of interaction with a chromogenic agent is eliminated. Due to the sensitivity of the reaction, the detection limit of triiodide, and therefore selenium, is extended toward lower values. RESULTS: The optimal conditions for the measurements were established: λ = 290 nm, pH = 1.0 - 1.5, reaction time = 15 minutes. Two areas of selenium detection were determined from the samples: 0.025 - 0.100 ppm, and 0.1 - 4.0 ppm. The detection limit of selenium was lowered at 0.100 ppm and even at 0.025 ppm, which significantly improves the sensitivity of the determination. Types of samples were specified which are suitable for analysis using the proposed method and explained why, in case of biological fluids, it must be used only accompanied by an adequate digestion method of the samples. CONCLUSIONS: Selenium can be measured by direct spectrophotometric determination of the triiodide anion resulting from the oxidation of iodide by selenium (IV) compounds from the sample. In this regard, a simple, direct, and sensitive determination method of selenium from the samples by UV-Vis spectrophotometry, without the use of chromogenic agents has been optimized.

Response to "using of 'pseudo-second-order model' in adsorption", comment letter on "phenol removal from wastewater by adsorption on zeolitic composite" [Bizerea Spiridon et al., Environ Sci Pollut Res (2013) 20:6367-6381].

This letter is a response to the issues put forth by Dr. Y.S. Ho with regard to the article "Phenol removal from wastewater by adsorption on zeolitic composite" as reported by Bizerea Spiridon et al. (Environ Sci Pollut Res 20:6367-6381, 2013). The response proposes to clarify the error slipped in the typewritten linearized equation of the pseudo-second-kinetic model and the reason for using secondary reference regarding this model.

Phenol removal from wastewater by adsorption on zeolitic composite.

It is well known that adsorption is an efficient method of removal of various pollutants from wastewater. The present study examines the phenol removal from water by adsorption on a new material, based on zeolitic volcanic tuff. This compound contains zeolitic tuff and cellulose, another known adsorbent, in a mass ratio of 4 to 1. The performances of the new adsorbent composite were compared with those of a widely used adsorbent material, zeolitic volcanic tuff. The adsorbent properties were tested on batch synthetic solutions containing 1-10 mg L(-1) (1-10 ppm) phenol, at room temperature without pH adjustment. The influence of the adsorbent dose, pH and contact time on the removal degree of phenol from water was investigated. The experimental data were modeled using the Langmuir, Freundlich, and Temkin adsorption isotherms. The Langmuir model was found to best represent our data revealing a monolayer adsorption with a maximum adsorption capacity between 0.12 and 0.53 mg g(-1) at 25 °C, for 2.00 g of adsorbent, depending on the initial phenol concentration. The adsorption kinetic study was performed using a pseudo-first- and pseudo-second-order kinetic models illustrating that phenol adsorption on zeolite composite is well described by pseudo-first kinetic equations. Our results indicated that phenol adsorption on the new adsorbent composite is superior to that on the classic zeolite.