Dzmitry Varabyou - Academia.edu (original) (raw)
Uploads
Papers by Dzmitry Varabyou
Journal of the Belarusian State University. Geography and Geology, 2021
The problems of the formation of hazardous natural and man-made processes in industrial cities, c... more The problems of the formation of hazardous natural and man-made processes in industrial cities, contributing to the emergence of environmental risks, are presented. To date, an extensive literary material has been accumulated on this problem, concerning the causes of its occurrence, analysis of the patterns of development, and the possibilities of managing risks, including the environmental ones. It has been established that the list of reasons for the formation of risks in cities lacks one of the most important factors that we have discovered – the structure of urban landscapes, which are quite large objects of urban development. To identify the role of these objects in the formation of environmental risks, the cities of Orsha and Pinsk were selected. These cities were laid down almost simultaneously at the beginning of the 11th century, but they have a different history of development. Maps of urban landscapes of cities were compiled, geochemical studies of their soil cover were c...
Journal of the Belarusian State University. Geography and Geology
The article presents the results of systematisation and mapping of the natural landscapes of Bela... more The article presents the results of systematisation and mapping of the natural landscapes of Belarus, which domestic researchers have been engaged since the 1960s. During this time, considerable cartographic and literary material concerning the peculiarities of distribution, a set of classification units and zoning units, approaches to their allocation and mapping has been accumulated. However, the appearance at the beginning of the 21st century of new research methods along with the possibility of using modern technologies determined the need to refine and detail many cartographic landscape developments. At the same period (2006–2015), a series of 1 : 500 000 scale wall-mounted physical and geographical maps was created in Belarus and updated information was obtained about the features of the territorial distribution of a number of components of nature. The appearance of such information, along with the available data of remote sensing of the Earth and the possibility of applicatio...
Frontiers in Immunology, 2020
Background: Variants in recombination-activating genes (RAG) are common genetic causes of autosom... more Background: Variants in recombination-activating genes (RAG) are common genetic causes of autosomal recessive forms of combined immunodeficiencies (CID) ranging from severe combined immunodeficiency (SCID), Omenn syndrome (OS), leaky SCID, and CID with granulomas and/or autoimmunity (CID-G/AI), and even milder presentation with antibody deficiency. Objective: We aim to estimate the incidence, clinical presentation, genetic variability, and treatment outcome with geographic distribution of patients with the RAG defects in populations inhabiting South, West, and East Slavic countries. Methods: Demographic, clinical, and laboratory data were collected from RAG-deficient patients of Slavic origin via chart review, retrospectively. Recombinase activity was determined in vitro by flow cytometry-based assay. Results: Based on the clinical and immunologic phenotype, our cohort of 82 patients from 68 families represented a wide spectrum of RAG deficiencies, including SCID (n = 20), OS (n = 37), and LS/CID (n = 25) phenotypes. Sixty-seven (81.7%) patients carried RAG1 and 15 patients (18.3%) carried RAG2 biallelic variants. We estimate that the minimal annual incidence of RAG deficiency in Slavic countries varies between 1 in 180,000 and 1 in 300,000 live births, and it may vary secondary to health care disparities in these regions. In our cohort, 70% (n = 47) of patients with RAG1 variants carried p.K86Vfs * 33 (c.256_257delAA) allele, either in homozygous (n = 18, 27%) or in compound heterozygous (n = 29, 43%) form. The majority (77%) of patients with homozygous RAG1 p.K86Vfs * 33 variant originated from Vistula watershed area in Central and Eastern Poland, and compound heterozygote cases were distributed among all Slavic countries except Bulgaria. Clinical and immunological presentation of homozygous RAG1 p.K86Vfs * 33 cases was highly diverse (SCID, OS, and AS/CID) suggestive of strong influence of additional genetic and/or epigenetic factors in shaping the final phenotype. Conclusion: We propose that RAG1 p.K86Vfs * 33 is a founder variant originating from the Vistula watershed region in Poland, which may explain a high proportion of homozygous cases from Central and Eastern Poland and the presence of the variant in all Slavs. Our studies in this cohort of RAG1 founder variants confirm that clinical and immunological phenotypes only partially depend on the underlying genetic defect. As access to HSCT is improving among RAG-deficient patients in Eastern Europe, we anticipate improvements in survival.
Frontiers in Immunology
Nijmegen breakage syndrome (NBS) is a DNA repair disorder characterized by combined immunodeficie... more Nijmegen breakage syndrome (NBS) is a DNA repair disorder characterized by combined immunodeficiency and a high predisposition to lymphoid malignancies. The majority of NBS patients are identified with a homozygous five base pair deletion in the Nibrin (NBN) gene (c.657_661del5, p.K219fsX19) with a founder effect observed in Caucasian European populations, especially of Slavic origin. We present here an analysis of a cohort of 136 NBS patients of Eastern Slav origin across Belarus, Ukraine, Russia, and Latvia with a focus on understanding the geographic distribution, incidence of malignancy, and treatment outcomes of this cohort. Our analysis shows that Belarus had the highest prevalence of NBS (2.3 per 1,000,000), followed by Ukraine (1.3 per 1,000,000), and Russia (0.7 per 1,000,000). Of note, the highest concentration of NBS cases was observed in the western regions of Belarus and Ukraine, where NBS prevalence exceeds 20 cases per 1,000,000 people, suggesting the presence of an “...
Journal of the Belarusian State University. Geography and Geology, 2021
The problems of the formation of hazardous natural and man-made processes in industrial cities, c... more The problems of the formation of hazardous natural and man-made processes in industrial cities, contributing to the emergence of environmental risks, are presented. To date, an extensive literary material has been accumulated on this problem, concerning the causes of its occurrence, analysis of the patterns of development, and the possibilities of managing risks, including the environmental ones. It has been established that the list of reasons for the formation of risks in cities lacks one of the most important factors that we have discovered – the structure of urban landscapes, which are quite large objects of urban development. To identify the role of these objects in the formation of environmental risks, the cities of Orsha and Pinsk were selected. These cities were laid down almost simultaneously at the beginning of the 11th century, but they have a different history of development. Maps of urban landscapes of cities were compiled, geochemical studies of their soil cover were c...
Journal of the Belarusian State University. Geography and Geology
The article presents the results of systematisation and mapping of the natural landscapes of Bela... more The article presents the results of systematisation and mapping of the natural landscapes of Belarus, which domestic researchers have been engaged since the 1960s. During this time, considerable cartographic and literary material concerning the peculiarities of distribution, a set of classification units and zoning units, approaches to their allocation and mapping has been accumulated. However, the appearance at the beginning of the 21st century of new research methods along with the possibility of using modern technologies determined the need to refine and detail many cartographic landscape developments. At the same period (2006–2015), a series of 1 : 500 000 scale wall-mounted physical and geographical maps was created in Belarus and updated information was obtained about the features of the territorial distribution of a number of components of nature. The appearance of such information, along with the available data of remote sensing of the Earth and the possibility of applicatio...
Frontiers in Immunology, 2020
Background: Variants in recombination-activating genes (RAG) are common genetic causes of autosom... more Background: Variants in recombination-activating genes (RAG) are common genetic causes of autosomal recessive forms of combined immunodeficiencies (CID) ranging from severe combined immunodeficiency (SCID), Omenn syndrome (OS), leaky SCID, and CID with granulomas and/or autoimmunity (CID-G/AI), and even milder presentation with antibody deficiency. Objective: We aim to estimate the incidence, clinical presentation, genetic variability, and treatment outcome with geographic distribution of patients with the RAG defects in populations inhabiting South, West, and East Slavic countries. Methods: Demographic, clinical, and laboratory data were collected from RAG-deficient patients of Slavic origin via chart review, retrospectively. Recombinase activity was determined in vitro by flow cytometry-based assay. Results: Based on the clinical and immunologic phenotype, our cohort of 82 patients from 68 families represented a wide spectrum of RAG deficiencies, including SCID (n = 20), OS (n = 37), and LS/CID (n = 25) phenotypes. Sixty-seven (81.7%) patients carried RAG1 and 15 patients (18.3%) carried RAG2 biallelic variants. We estimate that the minimal annual incidence of RAG deficiency in Slavic countries varies between 1 in 180,000 and 1 in 300,000 live births, and it may vary secondary to health care disparities in these regions. In our cohort, 70% (n = 47) of patients with RAG1 variants carried p.K86Vfs * 33 (c.256_257delAA) allele, either in homozygous (n = 18, 27%) or in compound heterozygous (n = 29, 43%) form. The majority (77%) of patients with homozygous RAG1 p.K86Vfs * 33 variant originated from Vistula watershed area in Central and Eastern Poland, and compound heterozygote cases were distributed among all Slavic countries except Bulgaria. Clinical and immunological presentation of homozygous RAG1 p.K86Vfs * 33 cases was highly diverse (SCID, OS, and AS/CID) suggestive of strong influence of additional genetic and/or epigenetic factors in shaping the final phenotype. Conclusion: We propose that RAG1 p.K86Vfs * 33 is a founder variant originating from the Vistula watershed region in Poland, which may explain a high proportion of homozygous cases from Central and Eastern Poland and the presence of the variant in all Slavs. Our studies in this cohort of RAG1 founder variants confirm that clinical and immunological phenotypes only partially depend on the underlying genetic defect. As access to HSCT is improving among RAG-deficient patients in Eastern Europe, we anticipate improvements in survival.
Frontiers in Immunology
Nijmegen breakage syndrome (NBS) is a DNA repair disorder characterized by combined immunodeficie... more Nijmegen breakage syndrome (NBS) is a DNA repair disorder characterized by combined immunodeficiency and a high predisposition to lymphoid malignancies. The majority of NBS patients are identified with a homozygous five base pair deletion in the Nibrin (NBN) gene (c.657_661del5, p.K219fsX19) with a founder effect observed in Caucasian European populations, especially of Slavic origin. We present here an analysis of a cohort of 136 NBS patients of Eastern Slav origin across Belarus, Ukraine, Russia, and Latvia with a focus on understanding the geographic distribution, incidence of malignancy, and treatment outcomes of this cohort. Our analysis shows that Belarus had the highest prevalence of NBS (2.3 per 1,000,000), followed by Ukraine (1.3 per 1,000,000), and Russia (0.7 per 1,000,000). Of note, the highest concentration of NBS cases was observed in the western regions of Belarus and Ukraine, where NBS prevalence exceeds 20 cases per 1,000,000 people, suggesting the presence of an “...