Olgica Nedić

Bio: Olgica Nedić is an academic researcher from University of Belgrade. The author has contributed to research in topics: Insulin & Insulin-like growth factor-binding protein. The author has an hindex of 17, co-authored 120 publications receiving 1037 citations. Previous affiliations of Olgica Nedić include Bucharest University of Economic Studies & Chemical Society.

Molecular effects of advanced glycation end products on cell signalling pathways, ageing and pathophysiology.

Abstract: Advanced glycation end-products (AGEs) are a heterogeneous group of compounds formed by the Maillard chemical process of non- enzymatic glycation of free amino groups of proteins, lipids and nucleic acids. This chemical modification of biomolecules is triggered by endogeneous hyperglycaemic or oxidative stress-related processes. Additionally, AGEs can derive from exogenous, mostly diet-related, sources. Considering that AGE accumulation in tissues correlates with ageing and is a hallmark in several age-related diseases it is not surprising that the role of AGEs in ageing and pathology has become increasingly evident. The receptor for AGEs (RAGE) is a single transmembrane protein being expressed in a wide variety of human cells. RAGE binds a broad repertoire of extracellular ligands and mediates responses to stress conditions by activating multiple signal transduction pathways being mostly responsible for acute and/or chronic inflammation. RAGE activation has been implicated in ageing as well as in a number of age-related diseases, including atherosclerosis, neurodegeneration, arthritis, stoke, diabetes and cancer. Here we present a synopsis of findings that relate to AGEs-reported implication in cell signalling pathways and ageing, as well as in pathology. Potential implications and opportunities for translational research and the development of new therapies are also discussed.

Analysis of protein carbonylation — pitfalls and promise in commonly used methods

Abstract: Oxidation of proteins has received a lot of attention in the last decades due to the fact that they have been shown to accumulate and to be implicated in the progression and the patho-physiology of several diseases such as Alzheimer, coronary heart diseases, etc. This has also resulted in the fact that research scientist became more eager to be able to measure accurately the level of oxidized protein in biological materials, and to determine the precise site of the oxidative attack on the protein, in order to get insights into the molecular mechanisms involved in the progression of diseases. Several methods for measuring protein carbonylation have been implemented in different laboratories around the world. However, to date no methods prevail as the most accurate, reliable and robust. The present paper aims at giving an overview of the common methods used to determine protein carbonylation in biological material as well as to highlight the limitations and the potential. The ultimate goal is to give quick tips for a rapid decision making when a method has to be selected and taking into consideration the advantage and drawback of the methods.

Periparturient endocrine and metabolic changes in healthy cows and in cows affected by mastitis.

Abstract: Summary Transition from pregnancy to lactation in dairy cows involves considerable metabolic adaptation. Additional stress is incurred during infections such as periparturient mastitis. Multiparous Holstein–Friesian cows kept under normal production conditions (n = 15) were used to evaluate changes in circulating metabolite and hormone concentrations from 5 days before to 5 days after calving. Insulin-like growth factor binding protein (IGFBP) profiles were also monitored. Marked time-related changes were observed for plasma thyroid hormone, IGF, cortisol, insulin, β-hydroxybutyrate (BHB) and non-esterified fatty acid (NEFA) concentrations but not for plasma leptin. A decrease in IGF-II concentration and maximal intensity of the putative IGFBP-1 band occurred at parturition. When compared with the five healthy cows, low IGF-II levels were prolonged to day 2 post-partum in five cows with Escherichia coli-associated mastitis. However, marked decreases in IGFBP-2 band intensity were evident only in two of the four cases examined. Individual total ligand (IGF-I + IGF-II) concentration and IGFBP pattern pre-partum were largely regained 5 days post-partum in all cows. Hormone and metabolite concentrations in the two cows with Staphylococcus aureus-associated mastitis were very similar to those in the five healthy cows. Plasma thyroxine (T4) was lower 2 days pre-partum in the cows, which later developed Gram-negative mastitis. Multiregression analysis showed that variance in T4 concentration was significantly and independently associated with triiodothyronine (T3) and IGF-I positively and with cortisol negatively (R2 = 0.648). This study confirms the close inter-relationship between the thyroid hormone and IGF axes in cattle and indicates possible effects of Gram-negative mastitis infection on IGF-II metabolism.

Characterisation of insulin-like growth factor receptors and insulin receptors in the human placenta using lectin affinity methods

Abstract: Insulin and insulin-like growth factor receptors (IR, IGF-IR, IGF-IIR) from human placental cell membranes were solubilised and their glycoprotein properties were studied in terms of their interaction with five lectins: wheat germ agglutinin (WGA), banana lectin (BanLec), phytohaemagglutinin (PHA), concanavalin A (Con A), and Sambucus nigra agglutinin (SNA). The pattern of binding to the immobilised lectins indicated that the glycosylation of the IGF-IR, IGF-IIR and IR differed. We found several populations of receptors in placental cell membranes, differing with respect to their oligosaccharide moieties. IGF-IIR populations bore highly branched complex type N -glycans with a very high content of oligosaccharides terminating with Sia, high-mannose type N -glycans and hybrid type N -glycans. All these glycans seemed to be attached to the same IGF-II receptor molecules. Two major glycoforms of IR were detected, one having multiple highly branched N -glycans with a low content of terminal Sia and the other, having high-mannose type glycans attached to multiple N -glycosylation sites. As for the IGF-IR, multiple glycoforms were detected, bearing complex type N -glycans with various content of Sia-terminating branches, hybrid type N -glycans or high-mannose type N -glycans. The specific binding of 125 I-IGF-II to its receptor increased in the presence of immobilised WGA and SNA, which might imply the existence of a mammalian lectin counterpart whose potential physiological significance may lie in different targeting to various membrane compartments, thereby potentially modifying their cell signalling pathways.

国际刊物《Scientometrics》文献计量研究

Abstract: 本文对国际科学计量学杂志《Ｓｃｉｅｎｔｏｍｅｔｒｉｃｓ》１９７９－１９９１年的研究论文内容、栏目、作者及国别和编委及国别作了计量分析，揭示出科学计量学研究的重点、活动的中心及发展趋势，说明了学科带头人在发展科学计量学这门新兴学科中的作用。

Biomonitoring Atmospheric Heavy Metals with Lichens: Theory and Application

Abstract: Recent records of environmental contamination noted a moderate decrease of SO2 pollution, whereas the burden of atmospheric heavy metals is still considerable. The present review refers to the entrapment, uptake, and accumulation of heavy metals by lichen thalli, made apparent by parameters of lichen vitality and stress. The particulate nature of airborne heavy metals is made evident by parameters referring to the entrapment of heavy-metal containing particles by lichen thalli. The mechanism of uptake of heavy metals, investigated by means of controlled experiments, refers to extracellular and intracellular uptake. The rate of absorption and the accumulation of heavy metals is dependent on morphological features of lichen thalli in addition to kind and intensity of emission sources and to nonanthropogenic factors such as climate and topography. The role of lichens as biomonitors is demonstrated by the case of lead. In contrast to data obtained by retrospective studies, using lichens as biomonitors of heav...

General Background on the Hypothalamic-Pituitary-Thyroid (HPT) Axis

Abstract: This article reviews the thyroid system, mainly from a mammalian standpoint. However, the thyroid system is highly conserved among vertebrate species, so the general information on thyroid hormone production and feedback through the hypothalamic-pituitary-thyroid (HPT) axis should be considered for all vertebrates, while species-specific differences are highlighted in the individual articles. This background article begins by outlining the HPT axis with its components and functions. For example, it describes the thyroid gland, its structure and development, how thyroid hormones are synthesized and regulated, the role of iodine in thyroid hormone synthesis, and finally how the thyroid hormones are released from the thyroid gland. It then progresses to detail areas within the thyroid system where disruption could occur or is already known to occur. It describes how thyroid hormone is transported in the serum and into the tissues on a cellular level, and how thyroid hormone is metabolized. There is an in-depth description of the alpha and beta thyroid hormone receptors and their functions, including how they are regulated, and what has been learned from the receptor knockout mouse models. The nongenomic actions of thyroid hormone are also described, such as in glucose uptake, mitochondrial effects, and its role in actin polymerization and vesicular recycling. The article discusses the concept of compensation within the HPT axis and how this fits into the paradigms that exist in thyroid toxicology/endocrinology. There is a section on thyroid hormone and its role in mammalian development: specifically, how it affects brain development when there is disruption to the maternal, the fetal, the newborn (congenital), or the infant thyroid system. Thyroid function during pregnancy is critical to normal development of the fetus, and several spontaneous mutant mouse lines are described that provide research tools to understand the mechanisms of thyroid hormone during mammalian brain development. Overall this article provides a basic understanding of the thyroid system and its components. The complexity of the thyroid system is clearly demonstrated, as are new areas of research on thyroid hormone physiology and thyroid hormone action developing within the field of thyroid endocrinology. This review provides the background necessary to review the current assays and endpoints described in the following articles for rodents, fishes, amphibians, and birds.

IGF-dependent and IGF-independent actions of IGF-binding protein-1 and -2: implications for metabolic homeostasis

Abstract: Insulin-like growth factor (IGF)-binding proteins (IGFBPs) confer temporospatial regulation to IGF bioactivity. Both stimulatory and inhibitory effects of IGFBPs on IGF actions have been described, and IGF-independent effects of several IGFBPs are emerging. Accumulating evidence indicates important roles for members of the IGFBP family in metabolic homeostasis. For example, IGFBP-1 concentrations fluctuate inversely in response to changes in plasma insulin levels, implicating IGFBP-1 in glucoregulation, and fasting levels of IGFBP-1 predict insulin sensitivity at the population level. IGFBP-2 concentrations reflect long-term insulin sensitivity and are reduced in the presence of obesity. Here, we review the evolving roles of IGFBP-1 and IGFBP-2 in metabolic homeostasis, summarize their effects on IGF bioactivity and explore putative mechanisms by which they might exert IGF-independent cellular actions.