SELENIUM LEVELS IN PEDIATRIC PATIENTS WITH ENDOCRINE DISEASES: EVIDENCE FROM A SYSTEMATIC REVIEW

Selenium (Se) is essential micronutrient involved in several physiological processes. In many regions around the world, a suboptimal intake of Se has been reported in several health conditions, also in pediatric age. Studies on association between Se level and diseases in children reported contrasting results. We took an aim to perform a systematic review of literature and provide evidence-based conclusion on the magnitude of Se deficit in endocrine diseases in children. PubMed, ISI WoS, and Scopus databases were searched to identify eligible studies, published until July 25, 2019. Methodological quality was assessed using Newcastle–Ottawa Scale. After careful selection, 13 eligible studies were included. Majority were conducted in Turkey (n=5) and Iran (n=5), and sample size varied from 61 to 628 children, with a mean (±SD) age of cases from 5.1±1.6 months up to 13.8±4.5 years. Eleven studies focused on different thyroid diseases, and two on children with type 1 diabetes mellitus (T1DM). In goitrous patients, Se level ranged from mean (±SD), 25.71±20.68 μg/L to 114.9±34.1 μg/L, while in patients with T1DM was 20.9±12.9 μg/mL and mean (95% CI)=58.4 μg/L (55.0–63.09). We may conclude that goiter and thyroid dysfunction are prominent signs of Se deficiency in children. Although deficiency of iodine and selenium are usually combined in some area, our systematic review showed that Se deficiency is important goitrogenic factor in school children. Further randomized controlled trials are needed to adequately explore the role of Se in endocrine disorders in children, across different populations and regions

STUDENTS’ INJURIES AT THE FACULTY OF SPORT AND PHYSICAL EDUCATION - AN ANALYSIS OF TWO STUDY PROGRAMS

The aim of this research is to analyze the injuries of the students of the Faculty of Sport and Physical Education, as well as to determine, if possible, if the increase in the number of injuries is caused by increased pressure, brought by a new study program, when doing exercises. The sample was composed of 207 participants, who attended the Faculty of Sport and Physical Education, University of Nis, aged 23 years ± 6 months. The questionnaire was the main measuring instrument for the evaluation of injuries. The participants were asked to answer by circling options concerning the location of their injury, the classes during which the injury occurred, as well as the type of injury. All the gathered data have been represented numerically and in percentages, and used for further analysis. The analysis of the gathered results showed that there is a higher index of injury during practice with students who have studied according to the Undergraduate academic study program, and that there is a difference in the rate of injuries in certain classes between the two study programs. The results of this study show that an increase in the intensity of work and increase in the teaching hours led to higher risk of injury. Future research, dealing with similar topics, on the basis of this research may compare students’ injuries in both the old and new school system, which gives this study a special significance

ANTIOXIDANTS AND THEIR IMPORTANCE DURING MUSCULAR EXERCISE: A REVIEW

Physiological levels of reactive oxygen species, as an essential part of the homeostatic milieu, are required for normal functioning of skeletal muscle. High levels of reactive oxygen species promote contractile dysfunction resulting in muscle weakness and fatigue, oxidative stress, apoptosis and necrosis of muscle cells. It is known that both resting and contracting skeletal muscles produce reactive oxygen species and reactive nitrogen species. The first suggestion that physical exercise results in free radical-mediated damage to tissues appeared in 1978. The newest researches investigate the mechanisms by which oxidants influence skeletal muscle contractile properties and explore how to protect muscle from oxidant-mediated dysfunction. Principal antioxidant enzymes include superoxide dismutase, glutathione peroxidase, and catalase. Numerous non-enzymatic antioxidants exist in cells within skeletal muscle fibers, the most abundant of which include glutathione, bilirubin, α-Lipoic acid , uric acid, and ubiquinones, or coenzyme Q (CoQ) andflavonoids. Dietary antioxidants are vitamins C- L ascorbic acid , vitamin A, retinol and their provitamins, carotenoids (especially β-carotene), vitamins E, tocopherol (especially a-tocoferol ), folic acid or folates. The usage of endogenous enzymatic and non-enzymatic antioxidants protects muscle from strong damaging effects caused by free radicals during acute exercise or longer term physical exercise. Scientific researches now confirm that the long-term use of antioxidants is safe and effective. The actual recommendation for physically active individuals is to ingest a diet rich in antioxidants

Heart Rate Variability in Children with Exercise-Induced Idiopathic Ventricular Arrhythmias

Ventricular arrhythmias (VAs) are common pediatric rhythm disorders requiring comprehensive laboratory evaluation. Although usually idiopathic, implying a benign character and favorable prognosis, the initial clinical approach is still not established in all cases. Considering their prognostic significance, exercise-induced (precipitated or aggravated) VAs usually require additional diagnostics, treatment, and follow-up. A number of reports have presented experimental and clinical evidence that increased sympathetic activity can initiate, or at least facilitate, VAs. Recent data highlight the relationship between exercise-induced idiopathic VAs (IVAs) and the long-term risk of cardiovascular death. The aim of this study was to assess the utility of heart rate variability (HRV) analysis as a noninvasive method for estimating autonomic nervous activity in children with exerciseinduced IVAs. The study included 42 children with IVAs, who were divided into two groups: children with exerciseinduced (precipitated or aggravated) IVAs and children with exercised-suppressed IVAs. Time-domain HRV parameters were analyzed from 24-h ambulatory electrocardiography recordings, and the majority of children underwent an exercise stress test using the McMaster protocol. The results of this study showed no significant changes in parasympathetic index, i.e., the square root of the mean of the sum of the squares of the differences between adjacent NN intervals (the length between two successive heartbeats) between the groups examined. On the other hand, we observed diminished time-domain values for the standard deviation of all adjacent NN intervals, as well as diminished time-domain values for standard deviation of the averages of NN intervals in all 5-min segments in the group of children with exercise-induced IVAs, implicating increased sympathetic activity in such individuals. HRV analysis could be a helpful diagnostic method, giving useful information regarding cardiac autonomic control in some children with exercise-induced IVAs. © Springer Science+Business Media, LLC 2009

Stable colloidal dispersions of fullerene C60, curcumin and C60-curcumin in water as potential antioxidants

Despite many advantages, the practical application of fullerene C60 and curcumin (CUR) has been limited by their hydrophobic nature, deficient solubility in aqueous media and, therefore, poor bioavailability. In this study, aqueous nanoformulations containing C60 and CUR in the absence and presence of three solubility enhancers, β-cyclodextrin (CD), Tween 80 (T80) and polyvinylpyrrolidone (PVP), were prepared and subjected to the antioxidant activity assessment. The content of C60 and CUR, stability, size and morphology of nanoparticles were determined using UV–vis, DLS and SEM techniques. Contrary to better solubility of pure C60 than the corresponding C60-CUR system, the solubilization of CUR in hybrid suspensions was improved compared to corresponding pure CUR suspensions, with the exception of the C60-CUR-PVP formulation. The DLS results revealed nearly monodisperse nature of CUR-T80 nanoformulation, while other ones ranged from widely dispersed to polydispersed. Depending on the type of solubilizer, similarity was observed in the particle size distributions of T80- and PVP-coated nanoformulations as well as water and CD nanoformulations. The presence of T80 differently and significantly reduces the particle size in all three nanoformulations, while PVP slightly reduces CUR-based nanoparticles but increases the size of C60 nanoparticles. Zeta potential values, ranging from − 9 mV to − 34 mV, show variation in the starting stability of nanoparticles, from unstable or relatively stable three PVP formulations and C60-T80 to highly stable CUR-T80 and C60-water. Compared to water nanoformulations as a control, SEM images of dispersant-coated nanoparticles lost the visible morphology of active components, showing variation in their morphology depending on the type of dispersant and active component used. Nanoformulations containing CUR in PVP and T80 expressed a very good antioxidant potential in DPPH radical scavenging assay, much stronger than ascorbic acid. At the same time, a moderate to high antioxidant activity in β-carotene bleaching assay was reached in PVP and T80 nanoformulations containing C60, CUR, and their noncovalent hybrid, as well. Our studies have shown that T80 and PVP colloidal systems containing C60-CUR hybrid, but also their individual components, can be used as stable antioxidant nanoformulations with potential application in the field of food and pharmacology

BEZGLUTENSKA DIJETA NECELIJAČNIH SPORTISTA - BENEFITI I POTENCIJALNI ŠTETNI EFEKTI

The aim of this paper is to present the latest scientific data related to a gluten-free diet, the justification of the introduction of a diet, the advantages and disadvantages of this dietary approach in the population of athletes. Non-celiac gluten sensitivity, previously defined as gluten sensitivity, is a relatively new clinical entity first defined in 2011. This disorder is characterized by intestinal symptoms (abdominal pain, bloating, diarrhea, and constipation) and extra intestinal symptoms such as headache, chronic fatigue, impaired concentration or “brain fog”, numbness and muscle or bone pain are frequently reported. Since most of the symptoms are subjective without accompanying clinical signs, and since no specific biomarker for diagnostics exists in clinical practice, there is always a dilemma whether this is really a health problem. A gluten-free diet has become popular among athletes due to the opinion that it has ergogenic effects. It should also be borne in mind that the introduction of a gluten-free diet has its drawbacks. Several studies suggest that a gluten-free diet is deficient in whole grains, dietary fiber, micronutrients and minerals. The data collected from the National Health and Nutrition Examination Survey study indicate the existence of higher concentrations of heavy metals in urine and blood samples taken from people following a gluten-free diet as a result of narrowed food choices. These data remind us to keep in mind the justification of the introduction of a gluten-free diet and the potential damage to health when observed adherence to this pattern of nutrition in the long run.Cilj ovog rada je da prikaže najnovije naučne podatke koji govore o bezglutenskoj dijeti, opravdanosti uvođenja dijete, prednostima i nedostacima ovakvog dijetarnog pristupa u populaciji sportista. Necelijačna glutenska senzitivnost (ranije definisana kao glutenska senzivnost) je relativno nov klinički entitet prvi put definisan 2011.godine. Ovaj poremećaj karakterišu intestinalni simptomi (abdominalni bol, nadimanje, proliv i zatvor) i ekstraintestinalni simptomi kao što su glavobolja, hronični umor, poremećaj koncentracije, osećaj trnjenja u rukama i nogama kao i bolovi u mišićima, zlobovima i kostima. S obzirom da je većina simptoma subjektivna bez pratećih kliničkih znakova, a kako ne postoji specifičan biomarker za dijagnostikovanje u kliničkoj praksi uvek postoji dilema da li se zaista radi o ovom zdravstvenom problemu. Bezglutenska dijeta je postala popularna među sportistima zbog mišljenja da ima ergogene efekte. Takođe treba imati na umu da uvođenje bezglutenske dijete ima svojih nedostataka. Više studija upućuju da je bezglutenska dijeta deficitarna u integralnim žitaricama, dijetnim vlaknim i pojedinim mikonutrijentima. Podaci prikupljeni iz NHANES studije (prema engl. the National Health and Nutrition Examination Survey), ukazuju na postojanje veće koncentracije teških metala u uzorcima urina i krvi uzetih od osoba na bezglutenskoj dijeti što je posledica suženog izbora namirnica. Ovi podaci podsećaju da treba imati na umu opravdanost uvođenja bezglutenske dijete i potencijalnu štetu po zdravlje kada dugoročno posmatramo pridržavanje ovakakvom obrascu ishrane

Polysaccharide-fullerene supramolecular hybrids: Synthesis, characterization and antioxidant activity

An efficient encapsulation of the fullerene into two hydrophobized and one native polysaccharide provided water soluble supramolecular hybrids. After covalent modification of polysaccharides by cholesterol, noncovalent hybrids were prepared by a three-step procedure, including mixing of individual aqueous solutions of hydrophobized, as well as native sugar with solution of the fullerene in pyridine, dialysis and lyophilization. Although the degree of the fullerene incorporation into hydrophobized substrates, cholesterol-levan and cholesterol-pullulan, was lower in comparison to the native polysaccharide levan, hydrophobization provided nanoparticles with improved properties. The particle size distribution, studied by dynamic light scattering and scanning electron microscopy revealed formation of moderately polydisperse aggregates, with the diameter contraction in comparison to the corresponding free polysaccharide, especially in the case of hydrophobized substrates. The morphological examination, done by scanning electron microscopy indicated the self-organization of the fullerene-native polysaccharide to round individual structures, while fullerene-hydrophobized polysaccharide hybrids tend to form networks. The antioxidant activity of the synthesized polysaccharide-C60 noncovalent hybrids versus starting polysaccharides was investigated by the DPPH radical scavenging and the β-carotene-linoleic acid bleaching methods. In all three complexes, the radical scavenging ability of the fullerene remained preserved, and a positive effect of levan hydrophobization was observed.The peer-reviewed version: [http://cherry.chem.bg.ac.rs/handle/123456789/3830