Siberia
Asia, Central
Indians, Central American
Radiometric Dating
Salmoniformes
Mongolia
Anseriformes
Russia
Arctic Regions
Burial
Seroprevalence of hepatitis B virus, hepatitis C virus and GB virus-C infections in Siberia. (1/177)
We studied the seroprevalence of hepatitis B virus (HBV), hepatitis C virus (HCV) and GB virus-C (GBV-C) infections in 348 Siberian natives who lived in the Kamchatka Peninsula of Russia. Of 348 samples studied, the seroprevalence of HBsAg and anti-HBs were 11.8% (41 of 348 samples) and 35.9% (125 of 348 samples), respectively. The prevalence of HCV infection was 1.4% (5 of 348 samples), and that of GBV-C RNA, using RT-PCR methods, was 7.5% (26 of 348 samples). In Siberia, the prevalences of HBV and GBV-C infections were about tenfold higher than those in Japan. The prevalence of HBsAg in subjects under 50 years of age was significantly higher than that in those over 50 years old (P < 0.05). Because HBV infection is highly endemic in Siberia, we propose that the community-based mass immunization must be conducted as soon as possible in this area. (+info)Thiorhodospira sibirica gen. nov., sp. nov., a new alkaliphilic purple sulfur bacterium from a Siberian soda lake. (2/177)
A new purple sulfur bacterium was isolated from microbial films on decaying plant mass in the near-shore area of the soda lake Malyi Kasytui (pH 9.5, 0.2% salinity) located in the steppe of the Chita region of south-east Siberia. Single cells were vibrioid- or spiral-shaped (3-4 microns wide and 7-20 microns long) and motile by means of a polar tuft of flagella. Internal photosynthetic membranes were of the lamellar type. Lamellae almost filled the whole cell, forming strands and coils. Photosynthetic pigments were bacteriochlorophyll a and carotenoids of the spirilloxanthin group. The new bacterium was strictly anaerobic. Under anoxic conditions, hydrogen sulfide and elemental sulfur were used as photosynthetic electron donors. During growth on sulfide, sulfur globules were formed as intermediate oxidation products. They were deposited outside the cytoplasm of the cells, in the peripheral periplasmic space and extracellularly. Thiosulfate was not used. Carbon dioxide, acetate, pyruvate, propionate, succinate, fumarate and malate were utilized as carbon sources. Optimum growth rates were obtained at pH 9.0 and optimum temperature was 30 degrees C. Good growth was observed in a mineral salts medium containing 5 g sodium bicarbonate l-1 without sodium chloride. The new bacterium tolerated up to 60 g sodium chloride l-1 and up to 80 g sodium carbonates l-1. Growth factors were not required. The DNA G + C composition was 56.0-57.4 mol%. Based on physiological, biochemical and genetic characteristics, the newly isolated bacterium is recognized as a new species of a new genus with the proposed name Thiorhodospira sibirica. (+info)Natural experimental models: the global search for biomedical paradigms among traditional, modernizing, and modern populations. (3/177)
During the past four decades, biomedical scientists have slowly begun to recognize the unique opportunities for studying biomedical processes, disease etiology, and mechanisms of pathogenesis in populations with unusual genetic structures, physiological characteristics, focal endemic disease, or special circumstances. Such populations greatly extend our research capabilities and provide a natural laboratory for studying relationships among biobehavioral, genetic, and ecological processes that are involved in the development of disease. The models presented illustrate three different types of natural experiments: those occurring in traditionally living, modernizing, and modern populations. The examples are drawn from current research that involves population mechanisms of adaptation among East African Turkana pastoralists; a search for etiology and mechanisms of pathogenesis of an emerging disease among the Yakut people of Siberia; and psychosocial stress, hypertension, and cardiovascular disease in women working outside the home in New York City and among subpopulations in Hawaii. The models in general, and the examples in specific, represent natural laboratories in which relatively small intrapopulation differences and large interpopulation differences can be used to evaluate health and disease outcomes. (+info)Biodosimetry results obtained by various cytogenetic methods and electron spin resonance spectrometry among inhabitants of a radionuclide contaminated area around the siberian chemical plant (Tomsk-7). (4/177)
On April 6, 1993, near the town of Tomsk (Russia) there was an accident at the Siberian Chemical Plant (SCP) which resulted in extensive contamination of an area of 250 km(2) to the north of SCP with long-lived radionuclides such as (239)Pu, (137)Cs and (90)Sr. Cytogenetic methods and electron spin resonance (ESR) spectrometry of tooth enamel were used to estimate the radiation doses received by the population. The ESR signal intensity and the chromosomal aberration frequency in lymphocytes of the tooth donors showed a good correlation. The data showed that 15% of the inhabitants of the Samus settlement received a radiation dose >90 cGy. The exceptions were results of an examination of fishermen, where ESR gave high values (80-210 cGy) but both the chromosome assay and the cytokinesis block micronucleus method gave lower ones (8-52 cGy). A large increase in chromosome damage was observed in people born between 1961 and 1969. It was found that during these years several serious accidents at the Siberian Chemical Plant had occurred causing radiation pollution of the area. The number of cells with chromosome aberrations was significantly less among the people arriving in Samus after 1980. We found good correlations between the level of carotene consumption and a decrease in frequency of both micronuclei in binucleated lymphocytes (r = 0.68, P < 0.01) and chromatid aberrations (r = 0.61, P < 0.01) among the inhabitants. We also examined the inhabitants of Samus for opisthorchis infection, which was present in 30% of the population. The Samus inhabitants affected by Opisthorchis felineus showed significantly increased levels of micronuclei in binucleated lymphocytes and chromatid aberrations as compared with the controls. (+info)Chromosome breakage at sites of oncogenes in a population accidentally exposed to radioactive chemical pollution. (5/177)
The purpose of the present study was to investigate the level of aberrations at fragile sites of chromosomes in peripheral blood lymphocytes of the population of an area polluted with radionuclides, following an accident at the Siberian Chemical Plant. We carried out the micronucleus test to screen people with radiation-related cytogenetic effects. Of the 1246 inhabitants of the settlement of Samus examined, 148 showed a significantly increased frequency of micronucleated erythrocytes and were selected for chromosome analysis as a radiation-exposed group. Additional analysis was carried out on 40 patients with gastric cancer and atrophic gastritis with stage II-III epithelial dysplasia. Eighty six individuals from a non-polluted area were used as a control group. Chromosomal breaks and exchanges occurred preferentially in chromosomes 3 and 6 among radiation-exposed persons and patients. The regions 3p14-25 and 6p23 were damaged most often. There was a tendency to preferential involvement of q21-25 of chromosome 6 in patients with gastric cancer and atrophic gastritis. Specific damage at certain chromosome sites was observed in the radiation-exposed population as well as in patients with gastric cancer. Most often this damage was located near oncogene loci, which could imply that chromosome damage induced by radiation is likely to be a predisposing factor to the expression of oncogenes and malignant transformation of cells in exposed individuals. (+info)Y-Chromosome evidence for a northward migration of modern humans into Eastern Asia during the last Ice Age. (6/177)
The timing and nature of the arrival and the subsequent expansion of modern humans into eastern Asia remains controversial. Using Y-chromosome biallelic markers, we investigated the ancient human-migration patterns in eastern Asia. Our data indicate that southern populations in eastern Asia are much more polymorphic than northern populations, which have only a subset of the southern haplotypes. This pattern indicates that the first settlement of modern humans in eastern Asia occurred in mainland Southeast Asia during the last Ice Age, coinciding with the absence of human fossils in eastern Asia, 50,000-100,000 years ago. After the initial peopling, a great northward migration extended into northern China and Siberia. (+info)Metabolic activity of permafrost bacteria below the freezing point. (7/177)
Metabolic activity was measured in the laboratory at temperatures between 5 and -20 degrees C on the basis of incorporation of (14)C-labeled acetate into lipids by samples of a natural population of bacteria from Siberian permafrost (permanently frozen soil). Incorporation followed a sigmoidal pattern similar to growth curves. At all temperatures, the log phase was followed, within 200 to 350 days, by a stationary phase, which was monitored until the 550th day of activity. The minimum doubling times ranged from 1 day (5 degrees C) to 20 days (-10 degrees C) to ca. 160 days (-20 degrees C). The curves reached the stationary phase at different levels, depending on the incubation temperature. We suggest that the stationary phase, which is generally considered to be reached when the availability of nutrients becomes limiting, was brought on under our conditions by the formation of diffusion barriers in the thin layers of unfrozen water known to be present in permafrost soils, the thickness of which depends on temperature. (+info)Thioalkalicoccus limnaeus gen. nov., sp. nov., a new alkaliphilic purple sulfur bacterium with bacteriochlorophyll b. (8/177)
Four strains of purple sulfur bacteria containing bacteriochlorophyll b were isolated from cyanobacterial mats of soda lakes in the steppe of south-east Siberia, Russia. Cells of all strains were cocci without gas vesicles. Eventually, cells with flagella were seen in the electron microscope, but motile cells were observed very rarely in cultures. Internal photosynthetic membranes were of the tubular type. Photosynthetic pigments were bacteriochlorophyll b and carotenoids with spectral characteristics similar to 3,4,3',4'-tetrahydrospirilloxanthin. The bacteria were obligately phototrophic and strictly anaerobic. Hydrogen sulfide and elemental sulfur were used as photosynthetic electron donors. Thiosulfate was not used. During growth on sulfide, sulfur globules were formed as intermediate oxidation products, deposited inside the cells and centrally located. In the presence of sulfide and sodium bicarbonate, acetate, malate, propionate, pyruvate, succinate, fumarate and yeast extract were photoassimilated. Growth factors were not required. The new bacterium is an obligate alkaliphile growing at pH 8-10 with an optimum at pH 9. It showed good growth up to 6.0% sodium chloride and up to 8.5% sodium carbonates. Phenotypically, it is similar to Thiococcus pfennigii, but different by virtue of its alkaliphily and salt tolerance. The DNA G+C content was 63.6-64.8 mol %, compared to 69.4-69.9 mol % for Thiococcus pfennigii. The 16S rDNA sequence of strain A26T was approximately 92% similar to that of Thiococcus pfennigii DSM 226 and therefore a new genus and species name, Thioalkalicoccus limnaeus gen. nov. and sp. nov., are proposed for the new bacterium. (+info)I'm sorry for any confusion, but "Siberia" is not a medical term. It's a geographical region in Russia, known for its harsh, cold climate and vast wilderness. If you have any questions about medical terms or concepts, I'd be happy to help answer those!
Central Asia is a geographical region in Asia that stretches from the Caspian Sea in the west to China in the east, and from Russia in the north to Afghanistan in the south. It includes the former Soviet republics of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan.
The medical definition of Central Asia may refer to the epidemiology, healthcare systems, or health issues specific to this region. For example, Central Asia has a high prevalence of infectious diseases such as tuberculosis, hepatitis, and HIV/AIDS, due to various factors including poverty, lack of access to healthcare, and mobility of populations. In addition, non-communicable diseases such as cardiovascular disease, cancer, and diabetes are also becoming more prevalent in Central Asia, partly due to lifestyle changes such as unhealthy diets, physical inactivity, and tobacco use.
Overall, the medical definition of Central Asia encompasses the unique health challenges and healthcare systems that exist within this geographical region.
I'm sorry for any confusion, but the term "Indians, Central American" is not a medical term. It refers to individuals or populations that originate from Central America and self-identify as indigenous or native to the region. In a medical context, it's more common to see specific references to individual ethnic groups or populations, such as Maya, Garifuna, or Miskitu, among others. These groups may have unique genetic characteristics, health risks, or cultural practices that are relevant to medical care and research. However, it's important to note that any discussion of medical issues should be sensitive to the individual's self-identified ethnicity and personal preferences.
Radiometric dating is a method used to determine the age of objects, including rocks and other fossilized materials, based on the decay rates of radioactive isotopes. This technique relies on the fact that certain elements, such as carbon-14, potassium-40, and uranium-238, are unstable and gradually decay into different elements over time.
By measuring the ratio of the remaining radioactive isotope to the stable end product, scientists can calculate the age of a sample using the following formula:
age = (ln(Nf/N0)) / λ
where Nf is the number of atoms of the decayed isotope, N0 is the initial number of atoms of the radioactive isotope, and λ is the decay constant.
Radiometric dating has been used to date objects ranging from a few thousand years old to billions of years old, making it an essential tool for archaeologists, geologists, and other scientists who study the history of our planet.
I apologize for any confusion, but "Salmoniformes" is not a medical term. It is a taxonomic category in biology, specifically an order of ray-finned fishes that includes salmon, trout, char, and related species. These fish are characterized by their adapted bodies for freshwater and saltwater living, and their important role in both commercial and recreational fishing.
I'm sorry for any confusion, but "Mongolia" is not a medical term. It is the name of a country located in Central Asia. If you have any questions about medical conditions or terminology, I would be happy to help clarify those for you.
I believe you may have made a typo in your question. "Archaeology" is the scientific study of past human cultures and societies through the recovery, examination, and analysis of material remains such as artifacts, buildings, biofacts (e.g., bones, shells), and cultural landscapes. It is not typically associated with medical definitions. If you intended to ask for a different term related to medicine or healthcare, please let me know so I can provide the correct information.
For more information about archaeology, you may be interested in visiting the World Archaeological Congress () or the Society for American Archaeology () websites to learn more about this fascinating field of study.
Anseriformes is a taxonomic order that includes approximately 150 species of waterfowl, such as ducks, geese, and swans. These birds are characterized by their short, stout bills, which often have serrated edges or a nail-like structure at the tip, and are adapted for filter-feeding or grazing on aquatic vegetation. Anseriformes species are found worldwide, with the exception of Antarctica, and they inhabit a wide range of wetland habitats, including freshwater lakes, rivers, marshes, and coastal estuaries. Many Anseriformes species are migratory and travel long distances between their breeding and wintering grounds. The order is divided into two families: Anatidae, which includes ducks, geese, and swans, and Anhimidae, which includes screamers, a group of large, terrestrial birds found in South America.
I'm sorry for any confusion, but "Russia" is not a medical term or concept. Russia is the largest country in the world by land area, located primarily in Asia with a smaller portion extending into Europe. It is a nation rich in history and culture, known for its diverse landscapes, from tundra and forests to subtropical beaches.
If you have any medical questions or terms that you would like me to define, please feel free to ask!
The Arctic region is not a medical term per se, but it is a geographical and environmental term that can have health-related implications. The Arctic is defined as the region surrounding the North Pole, encompassing the Arctic Ocean and parts of Canada, Greenland (Denmark), Russia, the United States (Alaska), Norway, Sweden, Finland, and Iceland. It is characterized by its cold climate, permafrost, and unique ecosystems.
Exposure to the harsh Arctic environment can pose significant health risks, such as hypothermia, frostbite, and other cold-related injuries. Additionally, the Arctic region has been impacted by climate change, leading to changes in the distribution of wildlife, which can have implications for food security and infectious disease transmission.
Therefore, while not a medical term itself, understanding the Arctic regions and their unique environmental and health challenges is important in fields such as wilderness medicine, environmental health, and public health.
A "cold climate" is not a medical term, but rather a geographical and environmental term. However, it is often used in the context of discussing health and medical issues, as cold climates can have various effects on human health.
In general, a cold climate is defined as a region where the average temperature remains below 15°C (59°F) throughout the year or where winter temperatures are consistently below freezing. These climates can be found in high latitudes, such as in the Arctic and Antarctic regions, as well as in mountainous areas at higher altitudes.
Exposure to cold temperatures can have both positive and negative effects on human health. On the one hand, cold weather can help to reduce inflammation and may have some benefits for people with certain medical conditions, such as multiple sclerosis. However, exposure to extreme cold can also increase the risk of hypothermia, frostbite, and other cold-related injuries.
Additionally, cold climates can exacerbate respiratory problems, such as asthma and bronchitis, and may increase the risk of developing respiratory infections like the common cold or flu. People with heart conditions may also be at greater risk in cold weather, as their blood vessels constrict to conserve heat, which can increase blood pressure and put additional strain on the heart.
Overall, while cold climates are not inherently "medical" in nature, they can have significant impacts on human health and well-being, particularly for vulnerable populations such as the elderly, young children, and people with chronic medical conditions.
I'm not a medical professional, but the term "History, Ancient" is not a medical term per se. However, in a broader context, it could refer to the study of ancient medical practices, theories, and beliefs that existed in civilizations prior to the Middle Ages or Classical Antiquity. This might include the examination of ancient texts, artifacts, and archaeological evidence to understand how illnesses were treated and viewed in these historical periods. It forms an essential part of the evolution of medical knowledge and practices over time.
Burial is the act or process of placing a deceased person or animal, usually in a specially dug hole called a grave, into the ground. The body may be placed in a casket, coffin, or shroud before burial. Burial is a common funeral practice in many cultures and religions, and it is often seen as a way to respect and honor the dead. In some cases, burial may also serve as a means of preventing the spread of disease. The location of the burial can vary widely, from a designated cemetery or graveyard to a private plot of land or even a body of water.
Phylogeny is the evolutionary history and relationship among biological entities, such as species or genes, based on their shared characteristics. In other words, it refers to the branching pattern of evolution that shows how various organisms have descended from a common ancestor over time. Phylogenetic analysis involves constructing a tree-like diagram called a phylogenetic tree, which depicts the inferred evolutionary relationships among organisms or genes based on molecular sequence data or other types of characters. This information is crucial for understanding the diversity and distribution of life on Earth, as well as for studying the emergence and spread of diseases.