Ingrid Žitňanová - Academia.edu (original) (raw)

Papers by Ingrid Žitňanová

Collection Symposium Series, 2005

Peptides, 2010

Ecdysis triggering hormones (ETH) from peripheral endocrine Inka cells initiate the ecdysis seque... more Ecdysis triggering hormones (ETH) from peripheral endocrine Inka cells initiate the ecdysis sequence through action on central neurons expressing ETH receptors (ETHR) in model moth and dipteran species. We used various biochemical, molecular and blast search techniques to detect these signaling molecules in representatives of diverse arthropods. Using peptide isolation from tracheal extracts, cDNA cloning or homology search, we identified ETHs in a variety of hemimetabolous and holometabolous insects. Most insects produce two related ETHs, but only a single active peptide was isolated from the cricket and one peptide is encoded by eth gene of the honeybee, parasitic wasp and aphid. Immunohistochemical staining with antiserum to Manduca PETH revealed Inka cells on tracheal surface of diverse insects. In spite of conserved ETH sequences, comparison of the natural and ETH-induced ecdysis sequence in the honeybee and beetle revealed considerable species-specific differences in pre-ecdysis and ecdysis behaviors. DNA sequences coding for putative ETHR were deduced from available genomes of several hemimetabolous and holometabolous insects. In all examined insects the ethr gene encodes two subtypes of the receptor (ETHR-A and ETHR-B). Phylogenic analysis showed that these receptors fall into a family of closely related GPCRs. Here we report for the first time presence of putative ETHs and ETHRs in genomes of other arthropods, the tick (Arachnida) and water flea (Crustacea). Possible source of ETH in ticks was detected in paired cells located in all pedal segments. Our results provide further evidence of structural and functional conservancy of ETH-ETHR signaling.

Proceedings of the National Academy of Sciences, 2004

Corazonin is a highly conserved neuropeptide hormone of wide-spread occurrence in insects yet is ... more Corazonin is a highly conserved neuropeptide hormone of wide-spread occurrence in insects yet is associated with no universally recognized function. After discovery of the corazonin receptor in Drosophila , we identified its ortholog in the moth, Manduca sexta , as a prelude to physiological studies. The corazonin receptor cDNA in M. sexta encodes a protein of 436 amino acids with seven putative transmembrane domains and shares common ancestry with its Drosophila counterpart. The receptor exhibits high sensitivity and selectivity for corazonin when expressed in Xenopus oocytes (EC 50 ≈ 200 pM) or Chinese hamster ovary cells (EC 50 ≈ 75 pM). Northern blot analysis locates the receptor in peripheral endocrine Inka cells, the source of preecdysis- and ecdysis-triggering hormones. Injection of corazonin into pharate larvae elicits release of these peptides from Inka cells, which induce precocious preecdysis and ecdysis behaviors. In vitro exposure of isolated Inka cells to corazonin (25...

Physiological Research, Oct 17, 2014

Oxidative stress is a phenomenon associated with imbalance between production of free radicals an... more Oxidative stress is a phenomenon associated with imbalance between production of free radicals and reactive metabolites (e.g. superoxide and hydrogen peroxide) and the antioxidant defences. Oxidative stress in individuals with Down syndrome (DS) has been associated with trisomy of the 21 st chromosome resulting in DS phenotype as well as with various morphological abnormalities, immune disorders, intellectual disability, premature aging and other biochemical abnormalities. Trisomy 21 in patients with DS results in increased activity of an important antioxidant enzyme Cu/Zn superoxide dismutase (SOD) which gene is located on the 21 st chromosome along with other proteins such as transcription factor Ets-2, stress inducing factors (DSCR1) and precursor of beta-amyloid protein responsible for the formation of amyloid plaques in Alzheimer disease. Mentioned proteins are involved in the management of mitochondrial function, thereby promoting mitochondrial theory of aging also in people with DS. In defence against toxic effects of free radicals and their metabolites organism has built antioxidant defence systems. Their lack and reduced function increases oxidative stress resulting in disruption of the structure of important biomolecules, such as proteins, lipids and nucleic acids. This leads to their dysfunctions affecting pathophysiology of organs and the whole organism. This paper examines the impact of antioxidant interventions as well as positive effect of physical exercise on cognitive and learning disabilities of individuals with DS. Potential terapeutic targets on the molecular level (oxidative stress markers, gene for DYRK1A, neutrophic factor BDNF) after intervention of natural polyphenols are also discussed.

Free Radical Research, 2006

The purpose of this randomized, double-blind and placebo controlled study was to test the effect ... more The purpose of this randomized, double-blind and placebo controlled study was to test the effect of polyphenolic extract of pine bark Pycnogenol w (Pyc) on the level of oxidized purines represented by 8-oxo-7,8-dihydroguanine (8-oxoG) and on the total antioxidant status (TAS) in children with attention deficit/hyperactivity disorder (ADHD). We have found significantly increased damage to DNA in ADHD children when compared to controls. 8-oxoG was significantly lower after 1 month of Pyc administration in comparison to the beginning state and to placebo group. TAS in ADHD children was lower in comparison to controls. After Pyc administration, TAS was elevated but statistically significant increase was recorded after 1 month of termination of Pyc application. Improvement of DNA damage and TAS after Pyc administration is associated with the improvement of attention in ADHD children. In conclusion, Pycnogenol w administration reduces oxidative damage to DNA, normalizes TAS and improves attention of ADHD children. Explanation of mutual relation between oxidative damage to DNA, TAS and symptoms of ADHD and mechanism of Pyc's action needs further investigations.

Zenodo (CERN European Organization for Nuclear Research), May 11, 2023

Bunková senescencia zohráva významnú úlohu v procese starnutia organizmu. Senescentné bunky hroma... more Bunková senescencia zohráva významnú úlohu v procese starnutia organizmu. Senescentné bunky hromadiace sa so zvyšujúcim sa vekom v organizme prispievajú k zhoršeniu funkcií tkanív a orgánov a rozvoju ochorení spojených so starnutím. V našej práci sme sledovali vplyv extraktu Pycnogenol® na rozvoj stresom indukovanej predčasnej senescencie, nakoľko Pycnogenol® (extrakt z kôry francúzskej prímorskej borovice Pinus pinaster) má výrazné antioxidačné vlastnosti a ukazuje sa aj jeho pozitívne pôsobenie na starnúci organizmus.

Redox Report, 2012

Objectives: This study was focused on the monitoring how the anti-inflammatory substance, N 1meth... more Objectives: This study was focused on the monitoring how the anti-inflammatory substance, N 1methylnicotinamide (MNA), could influence oxidation and glycooxidation stress markers in rats under conditions of streptozotocin (STZ)-induced diabetes mellitus. Methods: Diabetes mellitus was induced in 60 male Wistar rats by intraperitoneal injection of STZ and after 7 days diabetic animals were allocated to five groups according to the dose of MNA administered for 7 weeks. The degree of DNA damage in lymphocytes, as well as advanced glycation endproducts (AGEs), protein carbonyls, lipid peroxides, and total antioxidant capacity (TEAC) in plasma were measured. Results: Glycation damage to proteins (represented by AGEs level) was significantly increased in all diabetic groups compared to untreated non-diabetic animals. MNA did not affect TEAC of plasma in any group of diabetic rats. Supplementation of diabetic rats with MNA at the dose of 200 mg/kg resulted in decreased protein carbonyls (from 0.0818 ± 0.0091 to 0.0558 ± 0.0044 nmol/mg proteins; P < 0.05, n = 15) and DNA oxidation, reflected by the levels of 8-oxoG (0.6302 ± 0.085 vs. 0.9213 ± 0.108 8-oxoG/10 6 G; P < 0.05, n = 15), compared to untreated diabetic animals. Discussion: Our results demonstrated that MNA at suitable concentrations could influence oxidative modifications of proteins and DNA.

ISEE Conference Abstracts, 2020

SÚHRN Ultra malé superparamagnetické nanočastice oxidov železa (USPIONs) vďaka svojím fyzikálno-c... more SÚHRN Ultra malé superparamagnetické nanočastice oxidov železa (USPIONs) vďaka svojím fyzikálno-chemickým vlastnostiam majú veľký potenciál použitia v rôznych biomedicínskych a klinických aplikáciách. Niekoľko štúdií však popisuje, že podávanie rôznych nanočastíc oxidov železa, zvyčajne používaných ako kontrastné látky, môžu vyvolať oxidačný stres. Ich interakcie s biomakromolekulami sa však zriedka študovali a to najmä v podmienkach akútneho stresu. Keďže oxidačný stres zohráva významnú úlohu v patogenéze hypertenzie, je preto potrebné dôkladne poznať všetky mechanizmy, ktoré úzko súvisia s používaním nanočastíc v medicínskych aplikáciách. Táto štúdia bola navrhnutá za účelom sledovania vplyvu akútneho stresu a USPIONs na aktivitu katalázy v erytrocytoch normotenzných (WKY) a spontánne hypertenzných (SHR) potkanov. ABSTRACT Ultrasmall superparamagnetic iron oxide nanoparticles (USPIONs) have a great potential for use in a variety of biomedical and clinical applications due to their...

SÚHRN V rámci našich experimentov sme sa zamerali na sledovanie protektívnych účinkov vitamínu D ... more SÚHRN V rámci našich experimentov sme sa zamerali na sledovanie protektívnych účinkov vitamínu D na senescentné (starnúce) bunky MRC-5 v pasáži 21 (p21) a nesenescentné (mladé) bunky v pasáži 8 (p8) pred a po poškodení peroxidom vodíka. MTT testom sme zistili, že vitamín D zvýšil prežívanie buniek p8 nad 100 % v koncentrácii 20 µmol/L a 25 µmol/L. V prípade buniek p21 vitamín D zvýšil prežívanie buniek nad 100 % v koncentrácii 10 µmol/L a 25 µmol/L. Tieto zvýšenia však neboli signifikantné. Následne sme sledovali vplyv vitamínu D na poškodenie DNA buniek indukované peroxidom vodíka a zistili sme, že vitamín D vykazuje nielen protektívny, ale aj reparačný účinok. Tento účinok bol signifikantný v koncentráciách 1, 10, 20, 25 a 50 µmol/L. ABSTRACT In our experiments we focused on monitoring the protective effects of vitamin D on senescent MRC-5 cells at passage 21 (p21) and non-senescent cells at passage 8 (p8) before and after hydrogen peroxide damage. By MTT test we found that vitami...

Physiological Research, 2021

Autonomic nervous system (ANS) disorders are common in multiple sclerosis (MS). Previous studies ... more Autonomic nervous system (ANS) disorders are common in multiple sclerosis (MS). Previous studies showed differences in insulin resistance (IR) and lipoprotein levels in MS subjects compared to controls. Lipolysis caused by increased sympathetic activity could be one of the possible linking mechanisms leading to dyslipidemia in MS. Our study aimed to evaluate ANS activity in the context of glucose and lipid metabolism in people with MS. We prospectively measured short-term heart rate variability (HRV), fasting lipoprotein concentrations, and calculated IR indices based on plasma glucose and insulin levels during oral glucose tolerance test (oGTT) in 32 patients with MS and 29 healthy controls matched for age, sex and body mass index in our study. There was no significant difference in HRV parameters and lipoprotein levels between MS and controls. A significant positive correlation was found between low/high-frequency power ratio (LF/HF) and triglycerides (r=0.413, p=0.021) in MS subj...

Nutrition Research, 2003

The effect of Pycnogenol ® (PYC) (extract from the bark of the French maritime pine, Pinus pinast... more The effect of Pycnogenol ® (PYC) (extract from the bark of the French maritime pine, Pinus pinaster) and placebo on lipid metabolism, antioxidant status and erectile function was investigated in 21 patients suffering from erectile dysfunction (ED). The patients were treated with PYC (120 mg/day) or placebo for three months in a double-blind study. After three months of administration, PYC significantly improved ED (p Ͻ 0.05) from moderate to mild stage determined with International Index of Erectile Function (IIEF-5). Simultaneously, a significant increase of plasma antioxidant activity (p Ͻ 0.01) was observed. Three months after PYC administration, the level of total cholesterol decreased from 5.41 to 4.98 mmol/L and LDL-cholesterol from 3.44 to 2.78 mmol/L. Placebo had no effect. The levels of HDL-cholesterol and TAGs were not changed. Pycnogenol ® seems to have a beneficial effect on treatment of erectile dysfunction.

Physiological Research, 2019

Erectile dysfunction (ED) and diabetes mellitus (DM) share common pathophysiological risk factors... more Erectile dysfunction (ED) and diabetes mellitus (DM) share common pathophysiological risk factors including endothelial dysfunction which together with hyperglycemia contribute to the increased oxidative/glycooxidative stress. A reduced NO concentration is insufficient for relaxation processes in the penis. Chronic inflammation and endoglin are involved in the regulation of endothelial function. Adiponectin from the adipose tissue has anti-inflammatory effects. Our study aimed to investigate the relation between erectile function in patients with and without DM and the oxidative stress, hormone adiponectin, and endothelial dysfunction marker endoglin. Men (n=32) with ED evaluated by the International Index of Erectile function (IIEF-5) questionnaire (17 without DM (NDM); 15 with type 2 diabetes mellitus (DM)) and 31 controls were included. Advanced glycation end products (AGEs), 8-isoprostanes (8-isoP), protein carbonyls, antioxidant capacity, adiponectin and endoglin were determine...

$Research paper thumbnail of Endothelial Function in Patients with Multiple Sclerosis: The Role of GLP-1 Agonists, Lipoprotein Subfractions, and Redox Balance$

International Journal of Molecular Sciences

Introduction: Epidemiological studies have suggested an increased vascular risk in patients with ... more Introduction: Epidemiological studies have suggested an increased vascular risk in patients with multiple sclerosis (MS). There is increasing evidence of the beneficial effects of GLP-1 agonists (GLP-1a) in preventing vascular complications and slowing the progression of neurodegeneration. Our objective was to explore the changes in the endothelial function of MS patients after 12 months of GLP-1a therapy. We also explored the role of lipoprotein subfractions and the antioxidant capacity of plasma. Methods: MS patients were enrolled in a prospective, unicentric study. GLP-1a (dulaglutide) was administered to 13 patients. The control population consisted of 12 subjects. Endothelial function was determined by peripheral arterial tonometry and expressed as reperfusion hyperemia index (RHI). Trolox equivalent antioxidant capacity (TEAC) was used to assess the total antioxidant capacity of the plasma. The levels of lipoprotein subfractions were evaluated. Results: The GLP-1a group did no...

Food & Function, 2017

Senescence is a permanent cell cycle arrest that is accompanied by changes in cell morphology and... more Senescence is a permanent cell cycle arrest that is accompanied by changes in cell morphology and physiology occurringin vitroandin vivo.

$Research paper thumbnail of Lipoprotein Subfractions Associated with Endothelial Function in Previously Healthy Subjects with Newly Diagnosed Sleep Apnea—A Pilot Study$

Life

Background: Obstructive sleep apnea (OSA) activates several pathophysiological mechanisms which c... more Background: Obstructive sleep apnea (OSA) activates several pathophysiological mechanisms which can lead to the development of vascular diseases. Endothelial dysfunction (ED) is an initial step in the development of atherosclerosis. The association between ED and OSA has been described in several studies, even in previously healthy subjects. High-density lipoproteins (HDL) were generally considered to be atheroprotective, and low-density lipoprotein (LDL) to be an atherogenic component of lipoproteins. However, recent findings suggest a pro-atherogenic role of small HDL subfractions (8–10) and LDL subfractions (3–7). This study aimed to evaluate the relationship between endothelial function and lipid subfractions in previously healthy OSA subjects. Material and Methods: We prospectively enrolled 205 subjects with sleep monitoring. Plasma levels of triacylglycerols, total cholesterol, LDL, HDL, and their subfractions were assessed. Endothelial function was determined using peripheral...

Oxidative Medicine and Cellular Longevity

Due to unique properties, nanoparticles (NPs) have become a preferred material in biomedicine. Th... more Due to unique properties, nanoparticles (NPs) have become a preferred material in biomedicine. The benefits of their use are indisputable, but their safety and potential toxicity are becoming more and more important. Especially, excessive production of reactive oxygen species (ROS) induced by the strong oxidation potential of metal NPs could evoke adverse effects associated with damage to nucleic acids, proteins and lipids. Our study gives a view on the potential cytotoxicity of gold NPs (Au NPs) of different size from the perspective of the redox state of healthy (HEK 293 T) and cancer (A375 and A594) cell lines. These cells were incubated in the presence of two concentrations of Au NPs for 24 h or 72 h and total antioxidant capacity, 8-isoprostane, and protein carbonyl levels were determined. Furthermore, the activity of antioxidant enzymes such as superoxide dismutase, glutathione peroxidase, and catalase was detected in cell lysates. Our results compared to the results of other ...

Antioxidants, Apr 9, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Neuro endocrinology letters, 2019

OBJECTIVES To compare two different analytical methods for determination of small dense LDL and t... more OBJECTIVES To compare two different analytical methods for determination of small dense LDL and to determine a share of corresponding and non-corresponding (inconsistent) results METHODS: In the group of 104 hyperlipidemic patients and 20 healthy individuals of the control group we analysed the total cholesterol and triglycerides by enzymatic CHOD PAP method (Roche Diagnostics, Germany) in EDTA-K2 plasma. Small dense LDL (sdLDL) were quantified by the electrophoretic method for lipoprotein analysis on polyacrylamide gel (PAG) (Lipoprint LDL System, Quantimetrix, CA, USA) and simultaneously, the small dense LDL concentrations in the indentical samples were analysed by an enzymatic method LDL-EX ´Seiken´(Randox, England). RESULTS In 31 patients we found the discrepancy in the sdLDL levels using the two different procedures. Out of them, 24 patients tested by enzymatic method ´SEIKEN´ had higher sdLDL values (more than 0.9 mmol/l) compared to the Lipoprint LDL results, which identified...

Lipids in Health and Disease, 2021

Background Obstructive sleep apnea (OSA) is a disorder with a significant risk for cardiovascular... more Background Obstructive sleep apnea (OSA) is a disorder with a significant risk for cardiovascular diseases. Dyslipidemia and redox imbalance belong to potential mechanisms linking OSA with the development of vascular diseases. The main aim of this study was the evaluation of the presence of lipid abnormalities in OSA patients, focusing on small dense low-density lipoprotein (LDL) and high-density lipoprotein (HDL) subfractions and determination of the redox imbalance by evaluating the marker of oxidative damage to plasma lipids - lipoperoxides. Methods The study included 15 male subjects with polysomnographically confirmed OSA and 16 male healthy controls. Plasma levels of total cholesterol, LDL and HDL and their subfractions, triacylglycerols and lipoperoxides were determined in all study individuals. Plasma LDL and HDL subfractions were separated by the Lipoprint system which is a polyacrylamide gel electrophoresis. Lipoperoxide levels were determined spectrophotometrically. Resul...