Browsing by Author "Stanojević, Maja (57828665700)"

Hematophagous arthropods are important vectors for zoonotic pathogens. To date, a huge number of viruses have been identified in these arthropods, with a considerable proportion of them being human pathogens. However, the viromes of hematophagous arthropods are still largely unresearched. In this study, a number of arthropods were collected from Belgrade, Serbia including mosquitoes, ticks and bedbugs. The viromes of these arthropods were identified and characterized using Illumina MiSeq sequencing. In total, 21 viruses belonging to 11 families were characterized, with 11 of them representing novel species. These results may contribute to our knowledge of RNA viruses in arthropods and the discovery of novel human pathogens. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

Hematophagous arthropods are important vectors for zoonotic pathogens. To date, a huge number of viruses have been identified in these arthropods, with a considerable proportion of them being human pathogens. However, the viromes of hematophagous arthropods are still largely unresearched. In this study, a number of arthropods were collected from Belgrade, Serbia including mosquitoes, ticks and bedbugs. The viromes of these arthropods were identified and characterized using Illumina MiSeq sequencing. In total, 21 viruses belonging to 11 families were characterized, with 11 of them representing novel species. These results may contribute to our knowledge of RNA viruses in arthropods and the discovery of novel human pathogens. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

Previous molecular studies of Serbian HIV epidemic identified the dominance of subtype B and presence of clusters related HIV-1 transmission, in particular among men who have sex with men (MSM). In order to get a deeper understanding of the complexities of HIV sub-epidemics in Serbia, epidemic trends, temporal origin and phylodynamic characteristics in general population and subpopulations were analyzed by means of mathematical modeling, phylogenetic analysis and latent class analysis (LCA). Fitting of the logistic curve of trends for a cumulative annual number of new HIV cases in 1984–2016, in general population and MSM transmission group, was performed. Both datasets fitted the logistic growth model, showing the early exponential phase of the growth curve. According to the suggested model, in the year 2030, the number of newly diagnosed HIV cases in Serbia will continue to grow, in particular in the MSM transmission group. Further, a detailed phylogenetic analysis was performed on 385 sequences from the period 1997–2015. Identification of transmission clusters, estimation of population growth (Ne), of the effective reproductive number (Re) and time of the most recent common ancestor (tMRCA) were estimated employing Bayesian and maximum likelihood methods. A substantial proportion of 53% of subtype B sequences was found within transmission clusters/network. Phylodynamic analysis revealed Re over one during the whole period investigated, with the steepest slopes and a recent tMRCA for MSM transmission group subtype B clades, in line with a growing trend in the number of transmissions in years approaching the end of the study period. Contrary, heterosexual clades in both studied subtypes – B and C – showed modest growth and stagnation. LCA analysis identified five latent classes, with transmission clusters dominantly present in 2/5 classes, linked to MSM transmission living in the capital city and with the high prevalence of co-infection with HBV and/or other STIs. Presented findings imply that HIV epidemic in Serbia is still in the exponential growth phase, in particular, related to the MSM transmission, with estimated steep growth curve until 2030. The obtained results imply that an average new HIV patient in Serbia is a young man with concomitant sexually transmitted infection. Copyright © 2019 Jovanović, iljić, Ćirković, Salemović, Peić-Pavlović, Todorović, Ranin, Jevtović and Stanojević. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).

Previous molecular studies of Serbian HIV epidemic identified the dominance of subtype B and presence of clusters related HIV-1 transmission, in particular among men who have sex with men (MSM). In order to get a deeper understanding of the complexities of HIV sub-epidemics in Serbia, epidemic trends, temporal origin and phylodynamic characteristics in general population and subpopulations were analyzed by means of mathematical modeling, phylogenetic analysis and latent class analysis (LCA). Fitting of the logistic curve of trends for a cumulative annual number of new HIV cases in 1984–2016, in general population and MSM transmission group, was performed. Both datasets fitted the logistic growth model, showing the early exponential phase of the growth curve. According to the suggested model, in the year 2030, the number of newly diagnosed HIV cases in Serbia will continue to grow, in particular in the MSM transmission group. Further, a detailed phylogenetic analysis was performed on 385 sequences from the period 1997–2015. Identification of transmission clusters, estimation of population growth (Ne), of the effective reproductive number (Re) and time of the most recent common ancestor (tMRCA) were estimated employing Bayesian and maximum likelihood methods. A substantial proportion of 53% of subtype B sequences was found within transmission clusters/network. Phylodynamic analysis revealed Re over one during the whole period investigated, with the steepest slopes and a recent tMRCA for MSM transmission group subtype B clades, in line with a growing trend in the number of transmissions in years approaching the end of the study period. Contrary, heterosexual clades in both studied subtypes – B and C – showed modest growth and stagnation. LCA analysis identified five latent classes, with transmission clusters dominantly present in 2/5 classes, linked to MSM transmission living in the capital city and with the high prevalence of co-infection with HBV and/or other STIs. Presented findings imply that HIV epidemic in Serbia is still in the exponential growth phase, in particular, related to the MSM transmission, with estimated steep growth curve until 2030. The obtained results imply that an average new HIV patient in Serbia is a young man with concomitant sexually transmitted infection. Copyright © 2019 Jovanović, iljić, Ćirković, Salemović, Peić-Pavlović, Todorović, Ranin, Jevtović and Stanojević. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).

In this study, we investigated the mutation status of KRAS gene in pretherapeutic and preoperative biopsies in 63 specimens of locally advanced rectal cancers in order to evaluate its potential predictive and/or prognostic role. Regions of interest of KRAS exon 2 were amplified and visualized on 2% agarose gel. Obtained PCR products were subjected to direct sequencing. KRAS mutations were detected in 35% of patients, 91% of which were located in codon 12 and 9% in codon 13. In general, KRAS mutation status did not affect the response to neoadjuvant chemoradiotherapy (CRT). However, patients harboring mutated KRAS gene, simultaneously with high vascular endothelial growth factor (VEGF) expression, exhibited a worse response to CRT (p = 0.030), a more frequent appearance of local recurrences and distant metastasis (p = 0.003), and shorter overall survival (p = 0.001) compared to all others. On the contrary, patients with GGT>GCT KRAS mutation exhibited a significantly better response to CRT than those with any other type of KRAS mutation (p = 0.017). Moreover, the presence of GGT>GCT mutation was associated with low VEGF and Ki67 expression (p = 0.012 in both cases), parameters related to less aggressiveness of the disease. Our results suggest that KRAS mutation status could have some predictive and prognostic importance in rectal cancer when analyzed together with other parameters, such as VEGF and Ki67 expression. In addition, it seems that not only the presence but the type of KRAS mutation is important for examining its impact on CRT response. © 2016 Elsevier GmbH.

In this study, we investigated the mutation status of KRAS gene in pretherapeutic and preoperative biopsies in 63 specimens of locally advanced rectal cancers in order to evaluate its potential predictive and/or prognostic role. Regions of interest of KRAS exon 2 were amplified and visualized on 2% agarose gel. Obtained PCR products were subjected to direct sequencing. KRAS mutations were detected in 35% of patients, 91% of which were located in codon 12 and 9% in codon 13. In general, KRAS mutation status did not affect the response to neoadjuvant chemoradiotherapy (CRT). However, patients harboring mutated KRAS gene, simultaneously with high vascular endothelial growth factor (VEGF) expression, exhibited a worse response to CRT (p = 0.030), a more frequent appearance of local recurrences and distant metastasis (p = 0.003), and shorter overall survival (p = 0.001) compared to all others. On the contrary, patients with GGT>GCT KRAS mutation exhibited a significantly better response to CRT than those with any other type of KRAS mutation (p = 0.017). Moreover, the presence of GGT>GCT mutation was associated with low VEGF and Ki67 expression (p = 0.012 in both cases), parameters related to less aggressiveness of the disease. Our results suggest that KRAS mutation status could have some predictive and prognostic importance in rectal cancer when analyzed together with other parameters, such as VEGF and Ki67 expression. In addition, it seems that not only the presence but the type of KRAS mutation is important for examining its impact on CRT response. © 2016 Elsevier GmbH.

Liposarcoma represents the most frequent group of soft tissue sarcomas. The group can be divided into three different classes: (1) differentiated/ undifferentiated (WDLPS/DDLPS), (2) myxoid/round cell (MLPS/RCLPS) and (3) pleomorphic liposarcoma (PLS). It has become apparent that p53-p14 and Rb-p16 pathways play important roles in the pathogenesis of various sarcoma types. Molecular studies of the genes involved in these two pathways showed wide variations between the liposarcoma subtypes or even within the same subtype. We sought to examine mutational status of p53 and methylation status of p16 INK4a/p14ARF genes in primary and recurrent liposarcoma tumors. There were twelve myxoid (12/18, 66.7 %) and six pleomorphic liposarcoma (6/18, 33.3 %) samples. Immunohistochemical analysis revealed that p53 protein was overexpressed in 3/12 MLPS (25 %) and 6/6 PLS (100 %). Mutational analysis showed that 2/11 MLPS (18.2 %) and 2/6 PLS (33.3 %) contained mutated p53 gene. On the other hand, 3/18 samples (16.7 %) had methylated p16 promoter. However, the frequencies of the p14ARF gene methylation were 83.3 % (10/12) and 50 % (3/6) in myxoid and pleomorphic group, respectively. Overall, 15 out of 18 (83.3 %) samples had either p53 gene mutation or methylated p14 ARF promoter. The results from the current study suggest significant impact of the p14ARF gene methylation on the pathogenesis and progression of myxoid and to a lesser extent pleomorphic liposarcoma. Despite the limited number of samples, our study points to necessity of further investigation of p53-p14 and Rb-p16 pathways in liposarcoma. © Springer Science+Business Media New York 2013.

Liposarcoma represents the most frequent group of soft tissue sarcomas. The group can be divided into three different classes: (1) differentiated/ undifferentiated (WDLPS/DDLPS), (2) myxoid/round cell (MLPS/RCLPS) and (3) pleomorphic liposarcoma (PLS). It has become apparent that p53-p14 and Rb-p16 pathways play important roles in the pathogenesis of various sarcoma types. Molecular studies of the genes involved in these two pathways showed wide variations between the liposarcoma subtypes or even within the same subtype. We sought to examine mutational status of p53 and methylation status of p16 INK4a/p14ARF genes in primary and recurrent liposarcoma tumors. There were twelve myxoid (12/18, 66.7 %) and six pleomorphic liposarcoma (6/18, 33.3 %) samples. Immunohistochemical analysis revealed that p53 protein was overexpressed in 3/12 MLPS (25 %) and 6/6 PLS (100 %). Mutational analysis showed that 2/11 MLPS (18.2 %) and 2/6 PLS (33.3 %) contained mutated p53 gene. On the other hand, 3/18 samples (16.7 %) had methylated p16 promoter. However, the frequencies of the p14ARF gene methylation were 83.3 % (10/12) and 50 % (3/6) in myxoid and pleomorphic group, respectively. Overall, 15 out of 18 (83.3 %) samples had either p53 gene mutation or methylated p14 ARF promoter. The results from the current study suggest significant impact of the p14ARF gene methylation on the pathogenesis and progression of myxoid and to a lesser extent pleomorphic liposarcoma. Despite the limited number of samples, our study points to necessity of further investigation of p53-p14 and Rb-p16 pathways in liposarcoma. © Springer Science+Business Media New York 2013.

In recent years mathematical modeling has become a valuable tool in the analysis of infectious disease dynamics at both individual and population level. Mathematical models allow us to extrapolate from current information about the natural history of a disease, therapy/intervention outcome, state and progress of an outbreak, to predict the future and, most importantly, to quantify the uncertainty in these predictions, thus, increasingly gaining the ability to perform as a link between basic science, clinical medicine and public health. © GERMS 2012.

In recent years mathematical modeling has become a valuable tool in the analysis of infectious disease dynamics at both individual and population level. Mathematical models allow us to extrapolate from current information about the natural history of a disease, therapy/intervention outcome, state and progress of an outbreak, to predict the future and, most importantly, to quantify the uncertainty in these predictions, thus, increasingly gaining the ability to perform as a link between basic science, clinical medicine and public health. © GERMS 2012.