Papers by Marcela Valko-Rokytovská
Folia veterinaria, Mar 1, 2023
Lyme borreliosis (LB) is a multisystemic tick-borne disease that can affect many organs and have ... more Lyme borreliosis (LB) is a multisystemic tick-borne disease that can affect many organs and have various clinical manifestations in dogs. We attempted to summarise various aspects of Lyme disease: i. e., pathogenesis, epidemiology, benefits and risks of diagnostic approaches, treatment options, and prevention in dogs. Several diagnostic bottlenecks for LB in dogs and humans are compared. Because the occurrence of LB in both humans and dogs is closely related, monitoring its prevalence in dogs as sentinel animals is an excellent aid in assessing the risk of Lyme disease in a given geo graphic area. Although clinical symptoms in humans help clinicians diagnose LB, they are ineffective in dogs because canines rarely exhibit LB symptoms. Despite significant differences in sensitivity and specificity, serological twostep detection of antibodies against Borrelia spp. (ELISA and Western blot) is the most commonly used method in humans and dogs. The limitations of the assay highlight the need for further research to develop new clinical markers and more accurate diagnostic tests. Due to the lack of a specific allencompassing LB test, a definitive diagnosis of LB remains a difficult and timeconsuming process in human and veterinary medicine. Understanding the disease prevalence and diagnostics, as well as preventing its spread with effective and timely treatment, are fundamental principles of good disease management.
Journal of Chromatography & Separation Techniques, 2018
An ultra-high-performance chromatography for simultaneous separation and determination of the phe... more An ultra-high-performance chromatography for simultaneous separation and determination of the phenylalanine, tyrosine and their metabolites (vanillylmandelic acid, homovanillic acid, homogentisic acid), tryptophan and its metabolites (5-hydroxyindolacetic acid, kynurenic acid, indoxylsulphate, 3-indolacetic acid) was developed. The separation was carried out on Thermo Scientific Acclaim TM 120 C18 column with a mobile phase composed of methanol and water (containing 0.1% formic acid) in gradient mode at a flow rate of 0.6 mL/min. The limit of detection of 10-15 ng/mL and limit of quantitation of 29-45 ng/mL were determined. The method was evaluated in terms of recovery, precision, linearity, limit of detection, limit of quantification. The determined parameters are in the commonly acceptable ranges for that kind of analysis. The developed chromatographic method allows the rapid screening of urine metabolites, which can serve as potential markers of various tumor diseases as well as for the monitoring of treatment processes.
CERN European Organization for Nuclear Research - Zenodo, Oct 19, 2022
Folia Veterinaria, 2018
Nickel-binding proteins play an important role in the biological processes and can also be utiliz... more Nickel-binding proteins play an important role in the biological processes and can also be utilized in several fields of biotechnology. This study was focused on analysing the nickel-binding proteins from the blood sera of humans (Homo sapiens), cattle (Bos taurus), sheep (Ovis aries), red deer (Cervus elaphus), mouflon (Ovis orientalis), fallow deer (Dama dama), horses (Equus ferus caballus), pigs (Sus scrofa domesticus), wildboars (Sus scrofa), brown bears (Ursus arctos) and pheasants (Phasianus colchicus). The presence of higher abundance proteins in the blood serum, such as albumins, may mask the detection of lower abundance proteins. The samples were depleted from these higher abundance proteins to facilitate the detection of those with lower abundance. For the characterization of these proteins, nickel cations bound to tetradentate ligand nitrilotriacetic acid(Ni-NTA)immobilized on agarose beads were incubated with animal sera to capture nickel-binding proteins and subsequentl...
International Journal of Molecular Sciences
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
International Journal of Molecular Sciences
Urine autofluorescence at 295 nm is significantly higher in patients with malignant melanoma at e... more Urine autofluorescence at 295 nm is significantly higher in patients with malignant melanoma at each clinical stage compared to the healthy group. The largest difference is in the early-stages and without metastases. With increasing stage, the autofluorescence at 295 nm decreases. There is also a significant negative correlation between autofluorescence and Clark classification. Based on our results, it is assumed that the way malignant melanoma grows also affects urinary autofluorescence.
International Journal of Molecular Sciences, 2021
Breast cancer is the most common malignancy in women with high mortality. Sensitive and specific ... more Breast cancer is the most common malignancy in women with high mortality. Sensitive and specific methods for the detection, characterization and quantification of endogenous steroids in body fluids or tissues are needed for the diagnosis, treatment and prognosis of breast cancer and many other diseases. At present, non-invasive diagnostic methods are gaining more and more prominence, which enable a relatively fast and painless way of detecting many diseases. Metabolomics is a promising analytical method, the principle of which is the study and analysis of metabolites in biological material. It represents a comprehensive non-invasive diagnosis, which has a high potential for use in the diagnosis and prognosis of cancers, including breast cancer. This short review focuses on the targeted metabolomics of steroid hormones, which play an important role in the development and classification of breast cancer. The most commonly used diagnostic tool is the chromatographic method with mass sp...
This chapter presents an overview of possibilities for the therapy of melanoma, current knowledge... more This chapter presents an overview of possibilities for the therapy of melanoma, current knowledge and future direction. Skin cancer is one of the most frequent types of cancers. Melanoma is much less common than basal cell and squamous cell skin cancers, but it is far more dangerous. Detailed knowledge of melanoma at the molecular level allows to develop new treatment alternatives and to design effective new drugs. There are two approaches in therapy of melanoma in the present based on immunotherapy and targeted therapy or their combination. Immunotherapy includes immune checkpoint blockades, whereas targeted therapy is represented by protein kinase inhibitors, such as BRAF inhibitors, MEK inhibitors, and NRAS inhibitors. Detailed knowledge of protein structure and the understanding of its role in key signaling pathways in melanoma development lead to the designation of new protein kinase inhibitors in targeted therapy.
Journal of Veterinary Science, 2020
The identification of biomarkers that distinguish diseased from healthy individuals is of great i... more The identification of biomarkers that distinguish diseased from healthy individuals is of great interest in human and veterinary fields. In this research area, a metabolomic approach and its related statistical analyses can be useful for biomarker determination and allow noninvasive discrimination of healthy volunteers from breast cancer patients. In this study, we focused on the most common canine neoplasm, mammary gland tumor, and herein, we describe a simple method using ultra-high-performance liquid chromatography to determine the levels of tyrosine and its metabolites (epinephrine, 3,4-dihydroxy-L-phenylalanine, 3,4-dihydroxyphenylacetic acid, and vanillylmandelic acid), tryptophan and its metabolites (5-hydroxyindolacetic acid, indoxyl sulfate, serotonin, and kynurenic acid) in canine mammary cancer urine samples. Our results indicated significantly increased concentrations of three tryptophan metabolites, 5-hydroxyindolacetic acid (p < 0.001), serotonin, indoxyl sulfate (p < 0.01), and kynurenic acid (p < 0.05), and 2 tyrosine metabolites, 3,4-dihydroxy-L-phenylalanine (p < 0.001), and epinephrine (p < 0.05) in urine samples from the mammary gland tumor group compared to concentrations in urine samples from the healthy group. The results indicate that select urinary tyrosine and tryptophan metabolites may be useful as non-invasive diagnostic markers as well as in developing a therapeutic strategy for canine mammary gland tumors.
Medicina, 2019
Background and objectives: Melanin, which has a confirmed role in melanoma cell behaviour, is for... more Background and objectives: Melanin, which has a confirmed role in melanoma cell behaviour, is formed in the process of melanogenesis and is synthesized from tryptophan, L-tyrosine and their metabolites. All these metabolites are easily detectable by chromatography in urine. Materials and Methods: Urine samples of 133 individuals (82 malignant melanoma patients and 51 healthy controls) were analysed by reversed-phase high-performance liquid chromatography (RP-HPLC). The diagnosis of malignant melanoma was confirmed histologically. Results: Chromatograms of melanoma patients showed increased levels of 5,6-dihydroxyindole-2-carboxylic acid, vanilmandelic acid, homovanilic acid, tryptophan, 5-hydroxyindole-3-acetic acid, and indoxyl sulphate compared to healthy controls. Concentration of indoxyl sulphate, homovanilic acid and tryptophan were significantly increased even in the low clinical stage 0 of the disease (indoxyl sulphate, homovanilic acid and tryptophan in patients with clinica...
Neoplasma, 2016
Currently, skin cancer is one of the most frequent type of cancers. Melanoma is much less common ... more Currently, skin cancer is one of the most frequent type of cancers. Melanoma is much less common than basal cell and squamous cell skin cancers, but it is far more dangerous. Melanomas represent 3% of all skin cancers but 65% of skin cancer deaths. Detailed knowledge of melanoma at the molecular level allows the development of new treatment alternatives and to design effective new drugs. There are two approaches in therapy of melanoma in the present is based on immunotherapy and targeted therapy or their combination. Immunotherapy includes immune checkpoint blockades whereas targeted therapy is represented by protein kinase inhibitors. Detailed knowledge of protein structure and the understanding of their role in key signalling pathways in melanoma development lead to the designation of new protein kinase inhibitors in targeted therapy. In the future, it is necessary to conduct further clinical trials and collect more data about overall survival, response rates, appropriate timing and sequence of combination therapy to manage the complexity of melanoma treatment.
Prague medical report, 2010
Urine contains a variety of organic and inorganic chemicals including a number of natural fluorop... more Urine contains a variety of organic and inorganic chemicals including a number of natural fluorophores. Most of them are formed by tryptophan metabolites. But there are also metabolites of riboflavin, catecholamines and porphyrins. The alternation in the autofluorescence of urine and the alternation in the concentration of these substances are developed by both physiological and pathological changes such as disorder of body metabolism, dietary intake, age and etc. In this work we present fluorescent properties of chosen urine fluorophores - i.e. 5-hydroxyindole-3-acetic acid (5-HIAA), indoxyl sulphate (urine indican), serotonin (5-HT), vanillylmandelic (VMA) and homovanillic (HVA) acids typical for various diseases. Differences of fluorescent parameters of individual fluorophores measured in vitro in the water solutions and in natural environment of urine are significant and can lead to false results and conclusions. Therefore, we present the most common influence that can occur in ...
Spectroscopy Letters, 2014
ABSTRACT The fluorescent analysis of multicomponent biological materials is very difficult. To mo... more ABSTRACT The fluorescent analysis of multicomponent biological materials is very difficult. To model a proper system to characterize their quality is therefore indispensable. Influence of mixture composition was studied in a mixture of three naturally occurring diagnostically important urine metabolites: indoxyl sulfate, 5-hydroxyindole-3-acetic acid, and 3-methoxy-4-hydroxymandelic acid. Relationships between these compounds were monitored by measurement of synchronous fluorescence spectrum matrix. The fluorescence emission of 3-methoxy-4-hydroxymandelic acid when combined with indoxyl sulfate, or even with 5-hydroxyindole-3-acetic acid, was utilized for the excitation of indoxyl sulfate or 5-hydroxyindole-3-acetic acid, resulting in an increase in their fluorescence and in a decrease in 3-methoxy-4-hydroxymandelic acid fluorescence intensity.
Celiakia je multifaktorové, chronické, zápalové, autoimunitné ochorenie prejavujúce sa širokou šk... more Celiakia je multifaktorové, chronické, zápalové, autoimunitné ochorenie prejavujúce sa širokou škálou symptόmov. Genetická predispozícia súvisí s haplotypmi HLA-DQ2 a DQ8, ale bolo opísaných viac ako 60 asociovaných lokusov. Celosvetovo postihuje 0,5 až 1,0 % populácie, pričom medzi európskymi krajinami sú veľké rozdiely. Vyskytuje sa v rôznych formách a viaceré z nich nedisponujú anamnézou charakteristickou pre klasickú celiakiu. Napriek výrazným pokrokom v laboratórnej diagnostike sa v súčasnosti stále prezentuje ako ochorenie, ktoré je poddiagnostikované. Z toho dôvodu je dôležitá včasná a komplexná diagnostika.
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Papers by Marcela Valko-Rokytovská