Katerina Rebok

Katerina Rebok
Ss. Cyril and Methodius University in Skopje, Faculty of Natural Sciences and Mathematics-Skopje · Department of Cytology, Histology and Embryology

PhD

About

56
Publications
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262
Citations

Publications

Publications (56)
Article
Background and purpose: Pigmented macrophage aggregates (PMAs) are a part of the immune system of fish and are considered as valuable biomarkers of the impact of water pollution on fish health.Materials and methods: Immunomodulatory effect of water contaminated with high levels of metals on spleen and splenic PMAs of Vardar chub (Squalius vardarens...
Article
Full-text available
A lipoma is a benign tumour of mature adipocytes which may appear in various species, including marine and freshwater fish. It usually occurs in isolated locations, such as a superficial or deep mass, mainly in the skin and seldom in other organs. In non-mammalian vertebrates, there is no agreed minimal size for the mass to be considered a lipoma....
Article
The main aim of this study was to histochemically estimate the relative copper content in the liver during the breeding cycle of female Ohrid trout, a wild population endemic to the Ohrid Lake. The histology of the oogenetic cycle in this species was documented for the first time. Histochemistry with semi-quantification revealed positive correlatio...
Article
Pigmented macrophage aggregates (MAs) are known to change under influence of various factors, such as aging, season, starvation, and/or pollution. In this study, changes in the pigment content of the MAs in the spleen of Vardar chub (Squalius vardarensis, Karaman) (n = 129) collected in spring and autumn, from three rivers with different pollution...
Article
Full-text available
Crn Drim river is the single major outflow of the outstanding Ohrid lake. Surprisingly, data on the presence of heavy metals in waters and sediments for the whole Ohrid watershed are very scarce. This study presents the data on the concentration of heavy metals Fe, Mn, Zn, Cu, Cd and Pb in both waters and sediments collected along the river Crn Dri...
Article
For 22 days after monocrotaline injection two groups of rats received either of the monocarbonyl curcumin analogs (2E,6E)‐2,6‐bis(2‐bromobenzylidene)cycloxehanone (B2BrBC) and (2E,6E)‐2,6‐bis([2‐trifluoromethyl]benzylidene)cyclohexanone (C66), and their right ventricle parameters were compared to those from the control and the monocrotaline injected...
Article
Full-text available
Metals play crucial physiological roles, but they can also cause irreparable toxic effects through binding to important cellular biomolecules in aquatic organisms. The aim of this study was to determine the exact molecular masses and to identify several selected metal-binding biomolecules in hepatic and gill cytosols of Vardar chub (Squalius vardar...
Article
Freshwater contamination with mining waste can result with high concentrations of toxic metals in the water and in fish organs. In North- Eastern Macedonia, several rivers (e.g., Zletovska, Kriva) are exposed to acid mine drainage from active Pb/Zn mines. Previous studies confirmed high concentrations of dissolved metals in their water. This study...
Article
Full-text available
Iron is an essential micronutrient for the normal metabolism of all cells. Intracellular iron varies within normality ranges, and depletion or overload of brings serious consequences. As such, iron can also be deleterious when appearing as an environmental toxicant. The aim of this study was to estimate semi-quantitatively the liver iron content in...
Poster
Full-text available
Pathologic cardiac hypertrophy is a hallmark of heart dysfunction, myocardial ischemia, ventricular arrhythmias, and sudden death. The monocrotaline (MCT) rat model can be useful in evaluating pharmacological treatments for pulmonary arterial hypertension (PAH)-associated right ventricular (RV) hypertrophy. Oxidative stress, lipid peroxidation, inf...
Article
Full-text available
Heavy metal pollution of aquatic ecosystems is worldwide problem with consequences on the aquatic organisms. The concentrations of selected heavy metals (Fe, Mn, Zn, Cu, Cd and Pb) were determined in liver, kidney, gills, muscle and bone of barbel (Barbus rebeli) and chub (Squalius squalius) from the river Crn Drim in Macedonia. In general, liver a...
Article
Full-text available
Enzymatic biomarkers are sensitive to environmental changes and they respond by changing their activity. Barbus peloponnesius is considered a potential bioindicator to changes that can be caused in an environment by various pollutants. The results from the organs of the experimental group of fish from the aquaculture that were treated with a sublet...
Article
Many bioindicators have not yet been well characterized regarding their tendency to bind trace elements by different cytosolic biomolecules in response to trace element exposure. Accordingly, our principal aim was to define the cytosolic distributions of Cd, Co, Cu, Fe, Mn, Mo, Se, and Zn among the biomolecules of different molecular masses in live...
Conference Paper
Full-text available
Two decapod crustaceans from the family Astacidae occur in freshwater habitats in the Republic of Macedonia: noble crayfish Astacus astacus (Linnaeus 1758), and stone crayfish, Austropotamobius torrentium (Schrank 1803). Despite their importance in aquatic ecosystems, these species receive limited conservation attention and publicity in our country...
Article
Full-text available
Lipid peroxidation product, malondialdehyde (MDA), was studied in Vardar chub(Squalius vardarensis Karaman) as indicator of oxidative stress, using native fish from three rivers in northern Macedonia: mining impacted Zletovska and Kriva rivers, and agriculturally impacted Bregalnica River. MDA concentrations were measured in the intestine in spring...
Article
Full-text available
Changes in fish macrophage aggregate centres (MACs) are a useful indicator of environmental stress. In this study we evaluated stereologically the values of these cells in the polluted sites compared to the clean site in the River Bregalnica. MACs aggregates were randomly distributed in spleen and often showed irregular form. Dominant pig-ment in t...
Article
Full-text available
Integrated chemical and biomarker approaches were performed to estimate if there is ongoing toxicity in the River Bregalnica, namely connected with the presence of metals. The study was performed in water, sediment, and barbel (Barbus peloponnesius), collected in two seasons, from two suspected polluted and one reference zones. The water analyses r...
Article
Pollution with heavy metals may influence the immune system of fish, leading to impairment of their health or even increase their mortality. The fish kidney is one of the first fish organs to be affected by water contamination. Amounts of kidney macrophages (MACs), which are involved in fish immune response, as well as the qualitative and quantitat...
Article
Full-text available
In past decades macrophage aggregates (MACs) were being used in many monitoring studies as useful immu-nological biomarkers of environmental pollution and they are still encountered in the so-called “future biomarkers”, since quantitative studies in aquaculture and/or field of their normal fluctuations as a result of the influence of natural factor...
Article
Full-text available
The Republic of Macedonia is a country on the Balkan Peninsula without any history of forensic entomology use even when insects are the only available indicators of time since death. Here, we report forensic entomology cases in which the necrophagous blow fly Chrysomia albiceps was used for the first time to estimate the time between death and the...
Conference Paper
Full-text available
Trichoptera is a very rich order in the Balkan Peninsula, but knowledge of caddisflies in the Republic of Macedonia is still not complete. Adult caddisflies were collected during June 2016 on the Orevovecka Reka River, after the local fishpond, using ultraviolet (UV) light traps and an entomological hand net. Herein, Wormaldia juliani Kumanski, 197...
Conference Paper
The degradation of the water quality has become a major environmental concern due to continued anthropogenic pressure. To protect rivers, various methodologies have been developed to assess their ecological status. Several studies, have demonstrated that Chironomids (non-biting midges) are responsive to environmental changes with different species...
Article
Target screening of 463 organic contaminants in surface water using ultra high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) with direct injection was performed in spring of 2015 in northern Macedonia, at six sampling sites in four rivers belonging to Vardar basin: Kriva, Zletovska, Bregalnica and Var...
Article
This study on wild female Ohrid trout was primarily designed to provide a general overview of the breeding cycle influence upon selected aspects of hepatocytes. According with a semiquantitatively evaluation, some of these cell's structural compartments change during the breeding cycle. Structural modifications were disclosed in the relative occurr...
Article
Many natural freshwater ecosystems, especially in the north eastern Macedonia, are polluted with heavy metals, which are released by active mines. Long-term exposure to high levels of dissolved metals might result in increased metal bioaccumulation in organs of aquatic organisms, and consequently might cause various sub-toxic and toxic effects. The...
Article
Full-text available
The strong negative anthropogenic pressure on the River Bregalnica resulted in the increase of pollution in the river ecosystem. The aim of this study was to evaluate if aquatic pollutants generate genotoxic effects in barbel (Barbus peloponnesius). Thirty individuals were collected from three localities along the river: one control site and two lo...
Article
Ohrid trout stock levels have been declining for decades in the Europe’s oldest lake, Lake Ohrid, between Albania and Macedonia. Limited datasets indicate that this decrease is linked to overfishing and pollution. Histopathological hepatic lesions in fish have been regularly strongly associated with exposure to chemical contaminants. We collected b...
Article
The occurrence of overweight and obesity has become a world-wide problem. People with obesity or overweight have a much greater risk of developing different kinds of serious disease conditions. Obesity is not a problem only in developed countries; it is also starting to increase in developing countries as well. The Republic of Macedonia is a develo...
Article
Macrophages are involved in innate and acquired immune responses, being key players in immunotoxicology. Changes in the quantities of pigmented macrophage aggregates (PMQ) in fish are often used as biomarkers of pollution. Most studies offer only qualitative data on PMQ changes, and effects of age, sex and season are poorly known. We present a ster...
Article
Quantification of histopathological alterations in the gills of Vardar chub (Squalius vardarensis Karaman) was performed in 2012 in rivers of north-eastern Macedonia, with the aim to examine the effects of water quality in the rivers (Zletovska and Kriva River - impacted by active Pb/Zn mines ; Bregalnica River - contaminated by agricultural waste)...
Conference Paper
Full-text available
Pollution of surface water presents the major ecological problem in developed industrial world. Various human activities lead to the deterioration of water quality and mining presents one of those impacts. This need for resources has been proven to have extremely negative influence on all biological as well as physico-chemical characteristics of wa...
Conference Paper
Full-text available
Anthropogenic activities increase discharge of different pollutants in the aquatic environment which cause deterioration of the environment. Mining activities release in the environment different inorganic species and metals, which has negative effects on the water quality, aquatic organisms and humans. Aquatic organisms are affected by metal conce...
Conference Paper
Full-text available
Contamination of surface waters is a world-wide environmental problem. Anthropogenic activities like industry and mining can increase metal concentrations in the surface waters and may result in significant deterioration of water quality. Microorganisms are commonly used as biological indicators of surface water conditions. Microorganisms respond r...
Conference Paper
Full-text available
Fish parasites with a complex life cycle, including intermediate and paratenic hosts, can be used as indicators of aquatic environmental stress. Their identification is however often difficult, due to the high level of intraspecific variability. The aim of the present study was to identify metazoan parasites found in Vardar chub (Squalius vardarens...
Conference Paper
Full-text available
In the past decades, the interrelation between parasites and contaminants has gained increasing interest, especially in aquatic ecotoxicology. Fish intestinal parasites, acanthocephalans, were reported to effectively accumulate metals in concentrations that are orders of magnitude higher than those in the commonly used indicator organisms like fish...
Conference Paper
Full-text available
Mining activity can seriously affect the quality of surface water, especially regarding the levels of trace elements, which present a serious threat to the aquatic organisms because of their toxicity, persistence and bioaccumulation. The aim of this study was to assess bioavailability of metals and metalloids in the river water based on their accum...
Conference Paper
Full-text available
The natural environment of many river ecosystems, especially in the north eastern part of Macedonia, is more and more polluted with heavy metals, most of which were released into the environment by the active mines in this region. It could be presumed with high certainty that long-term exposure to high levels of dissolved metals will result in incr...
Conference Paper
Full-text available
Fish are frequently selected as the organisms of choice in aquatic biomonitoring due to their top position in the biotic communities and their sensitivity to low concentrations of environmental pollutants. Among other pollutants, metals represent a serious threat to the aquatic environment, since they are not biodegradable and can accumulate in the...
Conference Paper
Full-text available
Metallothionein (MT) and total cytosolic protein (TP) concentrations were determined as biomarkers of water contamination in gill and hepatic cytosols of Vardar chub (Squalius vardarensis) caught in three rivers in north-eastern Macedonia, one agriculturally impacted (Bregalnica) and two mining impacted (Zletovska and Kriva), in spring (May/June) o...
Conference Paper
Full-text available
Histopathological alterations on the gills of Vardar chub (Squalius vardarensis) were studied in three rivers in Pb/Zn mining region in north-eastern Macedonia. The Zletovska and Kriva River are directly impacted by active Pb/Zn mines Zletovo and Toranica, respectively, whereas the Bregalnica River is moderately contaminated mainly by agricultural...
Conference Paper
Full-text available
Disturbed natural balance as a result of significant pollution pressure by mining activities has been already reported for the major waterways in the Republic of Macedonia. An exceeded metal concentration in the aquatic environment has the potential to induce serious harm in wild organisms, to impair their health, condition, reproduction or their h...
Article
Changes in fish macrophages (Macs) are useful indicators of environmental pressures, but responses due to chemical and nonchemical stresses may be confounded by natural sources of variability. These may include sex and gonadal stage. In this study, we start addressing the following question: is the seasonally dependent ovary stage a factor to consi...
Article
Full-text available
Quantitative microscopic studies of season- and breeding-related changes in the liver of farm-raised fish are very scarce, and those of wild fish populations are virtually nonexistent. Moreover, none of the available studies investigated breeding-related changes in hepatic stroma, although it is already known that changes might exist in the parench...
Article
Full-text available
The Ohrid trout is an endemic autochthonous species dating from the Tertiary period with an unique ecologi-cal and commercial value. We still lack the basic knowledge of normal histology of many visceral organs in this species, including the spleen. To tackle this limitation, the investigation was focused on a histological description of the spleen...
Conference Paper
Full-text available
Natural perturbations and increased anthropogenic influences (water abstraction, canalization, damming, introductions of exotic species, agricultural and industrial waste waters) on freshwater resources have become more intense over the last few decades in the R. Macedonia. These alterations had direct and indirect influence on fish communities. Ri...
Article
This article contains the description of the origin and clasification of the new spermatogonia of Ohrid belvica (Acantholingua ohridana) in the period after the spawning. As to the new spermatogonial population we can conclude that in the latter phase of the postspawning period it is more present in the wall of the seminiferous lobules, an intesive...
Article
Fish macrophages (MACs) are judged useful in evaluating contamination, but responses due to chemical exposure must be distinguished from the natural sources of variability. It is well known that several natural factors (such as aging and nutrition) influence those cells, but it is not established whether MACs undergo seasonal and breeding dependent...
Article
In this paper a comparative analysis of interlobular interstitium od Dojran perch (Perca fluviatilis macedonica Kar.) and Ohrid trout (Salmo letnica Kar.) in prespawning and post spawning period is made. The vascularization on the level of interlobular interstitium in the prespawning period in Dojran perch is enormously narrowed, minimally present,...
Article
Summary Tavciovska-Vasileva, I. & K. Rebok, 2005. Ultrastructural changes in Sertoli cells in Ohrid trout - Salmo letnica (Karaman) during the prespawning and postspawning period. Bulg. J. Vet. Med., 8, No 1, 47�57. A cytological analysis based on ultrastructural findings in some regions of Ohrid trouttestesSalmo letnica (Karaman) in the prespawnin...
Article
In this paper the ultrastructural analysis of macrophages of the testes of salmonidae from Ohrid lake has been done. In the seminiferous lobules of Ohrid trout, Salmo letnica (Karaman) and Ohrid belvica (Acantholingua ohridana) where Sertoli degenerated material is present, it is characteristic that there are macrophages located in the wall of the...
Article
Full-text available
For evaluating pollution impacts on aquatic ecosystems there is a need to establish early- warning signals (biomarkers) using bioindicator organisms. Some studies suggested that rodlet cells (RCs) changes in fish can be used as pollution biomarkers. Looking for supporting evidence, we quantitatively estimate the RCs amounts in liver, as well as gen...

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