Emigrants and Immigrants: People who leave their place of residence in one country and settle in a different country.Emigration and Immigration: The process of leaving one's country to establish residence in a foreign country.Thymus Gland: A single, unpaired primary lymphoid organ situated in the MEDIASTINUM, extending superiorly into the neck to the lower edge of the THYROID GLAND and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.Thymectomy: Surgical removal of the thymus gland. (Dorland, 28th ed)Gene Rearrangement, T-Lymphocyte: Ordered rearrangement of T-cell variable gene regions coding for the antigen receptors.Thymocytes: HEMATOPOIETIC PROGENITOR CELLS that have migrated to the THYMUS where they differentiate into T-LYMPHOCYTES. Thymocytes are classified into maturational stages based on the expression of CELL SURFACE ANTIGENS.Rats, Inbred BB: A strain of Rattus norvegicus which is a model for spontaneous insulin-dependent diabetes mellitus (DIABETES MELLITUS, INSULIN-DEPENDENT).T-Lymphocyte Subsets: A classification of T-lymphocytes, especially into helper/inducer, suppressor/effector, and cytotoxic subsets, based on structurally or functionally different populations of cells.Lymphopenia: Reduction in the number of lymphocytes.Cell Movement: The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.CD4-Positive T-Lymphocytes: A critical subpopulation of T-lymphocytes involved in the induction of most immunological functions. The HIV virus has selective tropism for the T4 cell which expresses the CD4 phenotypic marker, a receptor for HIV. In fact, the key element in the profound immunosuppression seen in HIV infection is the depletion of this subset of T-lymphocytes.Lymphocyte Count: The number of LYMPHOCYTES per unit volume of BLOOD.Interleukin-7: A cytokine produced by bone marrow stromal cells that promotes the growth of B-LYMPHOCYTE precursors and is co-mitogenic with INTERLEUKIN-2 for mature T-LYMPHOCYTE activation.T-Lymphocytes: Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.Somalia: Somalia is located on the east coast of Africa on and north of the Equator and, with Ethiopia, Eritrea, Djibouti, and Kenya, is often referred to as the Horn of Africa. It comprises Italy's former Trust Territory of Somalia and the former British Protectorate of Somaliland. The capital is Mogadishu.Receptors, Antigen, T-Cell: Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens (ANTIGENS, CD3). Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta (RECEPTORS, ANTIGEN, T-CELL, ALPHA-BETA) or gamma-delta (RECEPTORS, ANTIGEN, T-CELL, GAMMA-DELTA) chains.Asian Americans: Persons living in the United States having origins in any of the original peoples of the Far East, Southeast Asia, or the Indian subcontinent.Refugees: Persons fleeing to a place of safety, especially those who flee to a foreign country or power to escape danger or persecution in their own country or habitual residence because of race, religion, or political belief. (Webster, 3d ed)USSRCD4-CD8 Ratio: Ratio of T-LYMPHOCYTES that express the CD4 ANTIGEN to those that express the CD8 ANTIGEN. This value is commonly assessed in the diagnosis and staging of diseases affecting the IMMUNE SYSTEM including HIV INFECTIONS.Lymphoid Tissue: Specialized tissues that are components of the lymphatic system. They provide fixed locations within the body where a variety of LYMPHOCYTES can form, mature and multiply. The lymphoid tissues are connected by a network of LYMPHATIC VESSELS.CD8-Positive T-Lymphocytes: A critical subpopulation of regulatory T-lymphocytes involved in MHC Class I-restricted interactions. They include both cytotoxic T-lymphocytes (T-LYMPHOCYTES, CYTOTOXIC) and CD8+ suppressor T-lymphocytes.Antigens, CD45: High-molecular weight glycoproteins uniquely expressed on the surface of LEUKOCYTES and their hemopoietic progenitors. They contain a cytoplasmic protein tyrosine phosphatase activity which plays a role in intracellular signaling from the CELL SURFACE RECEPTORS. The CD45 antigens occur as multiple isoforms that result from alternative mRNA splicing and differential usage of three exons.Hispanic Americans: Persons living in the United States of Mexican (MEXICAN AMERICANS), Puerto Rican, Cuban, Central or South American, or other Spanish culture or origin. The concept does not include Brazilian Americans or Portuguese Americans.Transients and Migrants: People who frequently change their place of residence.Europe, EasternFlow Cytometry: Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.L-Selectin: Cell adhesion molecule and CD antigen that serves as a homing receptor for lymphocytes to lymph node high endothelial venules.Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.Homeostasis: The processes whereby the internal environment of an organism tends to remain balanced and stable.Mice, Inbred C57BLCentral AmericaAsia: The largest of the continents. It was known to the Romans more specifically as what we know today as Asia Minor. The name comes from at least two possible sources: from the Assyrian asu (to rise) or from the Sanskrit usa (dawn), both with reference to its being the land of the rising sun, i.e., eastern as opposed to Europe, to the west. (From Webster's New Geographical Dictionary, 1988, p82 & Room, Brewer's Dictionary of Names, 1992, p34)Mexican Americans: Persons living in the United States of Mexican descent.Immunophenotyping: Process of classifying cells of the immune system based on structural and functional differences. The process is commonly used to analyze and sort T-lymphocytes into subsets based on CD antigens by the technique of flow cytometry.Morocco: A country located in north Africa, bordering the Atlantic Ocean and the Mediterranean Sea, with a southern border with Western Sahara, eastern border with Algeria. The capital is Rabat.West Indies: Islands lying between southeastern North America and northern South America, enclosing the Caribbean Sea. They comprise the Greater Antilles (CUBA; DOMINICAN REPUBLIC; HAITI; JAMAICA; and PUERTO RICO), the Lesser Antilles (ANTIGUA AND BARBUDA and the other Leeward Islands, BARBADOS; MARTINIQUE and the other Windward Islands, NETHERLANDS ANTILLES; VIRGIN ISLANDS OF THE UNITED STATES, BRITISH VIRGINI ISLANDS, and the islands north of Venezuela which include TRINIDAD AND TOBAGO), and the BAHAMAS. (From Webster's New Geographical Dictionary, 1988, p1330)Spain: Parliamentary democracy located between France on the northeast and Portugual on the west and bordered by the Atlantic Ocean and the Mediterranean Sea.Spleen: An encapsulated lymphatic organ through which venous blood filters.Receptors, Antigen, T-Cell, alpha-beta: T-cell receptors composed of CD3-associated alpha and beta polypeptide chains and expressed primarily in CD4+ or CD8+ T-cells. Unlike immunoglobulins, the alpha-beta T-cell receptors recognize antigens only when presented in association with major histocompatibility (MHC) molecules.Haiti: A republic in the Greater Antilles in the West Indies. Its capital is Port-au-Prince. With the Dominican Republic it forms the island of Hispaniola - Haiti occupying the western third and the Dominican Republic, the eastern two thirds. Haiti belonged to France from 1697 until its rule was challenged by slave insurrections from 1791. It became a republic in 1820. It was virtually an American protectorate from 1915 to 1934. It adopted its present constitution in 1964 and amended it in 1971. The name may represent either of two Caribbean words, haiti, mountain land, or jhaiti, nest. (From Webster's New Geographical Dictionary, 1988, p481 & Room, Brewer's Dictionary of Names, 1992, p225)Latin America: The geographic area of Latin America in general and when the specific country or countries are not indicated. It usually includes Central America, South America, Mexico, and the islands of the Caribbean.Suriname: A republic in the north of South America, bordered on the west by GUYANA (British Guiana) and on the east by FRENCH GUIANA. Its capital is Paramaribo. It was formerly called Netherlands Guiana or Dutch Guiana or Surinam. Suriname was first settled by the English in 1651 but was ceded to the Dutch by treaty in 1667. It became an autonomous territory under the Dutch crown in 1954 and gained independence in 1975. The country was named for the Surinam River but the meaning of that name is uncertain. (From Webster's New Geographical Dictionary, 1988, p1167 & Room, Brewer's Dictionary of Names, 1992, p526)AfricaLymph Nodes: They are oval or bean shaped bodies (1 - 30 mm in diameter) located along the lymphatic system.United StatesNetherlands Antilles: Former Netherlands overseas territory in the Lesser Antilles in the West Indies. It had included the islands of Aruba, Bonaire, Curacao, Saba, St. Eustatius, and the southern part of St. Martin. The Netherlands Antilles dissolved on October 10, 2010. Aruba, Curacao and Sint Maarten became autonomous territories of the Kingdom of the Netherlands. Bonaire, Saba, and Sint Eustatius are under the direct administration of the Netherlands. (From US Department of State, Background Note)IsraelMexicoCell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Socioeconomic Factors: Social and economic factors that characterize the individual or group within the social structure.Ethnic Groups: A group of people with a common cultural heritage that sets them apart from others in a variety of social relationships.Mice, Transgenic: Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.Culture: A collective expression for all behavior patterns acquired and socially transmitted through symbols. Culture includes customs, traditions, and language.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Immunologic Memory: The altered state of immunologic responsiveness resulting from initial contact with antigen, which enables the individual to produce antibodies more rapidly and in greater quantity in response to secondary antigenic stimulus.Cultural Characteristics: Those aspects or characteristics which identify a culture.Language: A verbal or nonverbal means of communicating ideas or feelings.Health Services Accessibility: The degree to which individuals are inhibited or facilitated in their ability to gain entry to and to receive care and services from the health care system. Factors influencing this ability include geographic, architectural, transportational, and financial considerations, among others.HIV Infections: Includes the spectrum of human immunodeficiency virus infections that range from asymptomatic seropositivity, thru AIDS-related complex (ARC), to acquired immunodeficiency syndrome (AIDS).Canada: The largest country in North America, comprising 10 provinces and three territories. Its capital is Ottawa.Caribbean Region: The area that lies between continental North and South America and comprises the Caribbean Sea, the West Indies, and the adjacent mainland regions of southern Mexico, Central America, Colombia, and Venezuela.Yugoslavia: Created as the Kingdom of Serbs, Croats, and Slovenes in 1918. Yugoslavia became the official name in 1929. BOSNIA-HERZEGOVINA; CROATIA; and SLOVENIA formed independent countries 7 April 1992. Macedonia became independent 8 February 1994 as the Former Yugoslav Republic of Macedonia (MACEDONIA REPUBLIC).South AmericaCommunication Barriers: Those factors, such as language or sociocultural relationships, which interfere in the meaningful interpretation and transmission of ideas between individuals or groups.Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Cross-Sectional Studies: Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.New York CityLymphocyte Activation: Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.Africa, Northern: The geographical area of Africa comprising ALGERIA; EGYPT; LIBYA; MOROCCO; and TUNISIA. It includes also the vast deserts and oases of the Sahara. It is often referred to as North Africa, French-speaking Africa, or the Maghreb. (From Webster's New Geographical Dictionary, 1988, p856)Middle East: The region of southwest Asia and northeastern Africa usually considered as extending from Libya on the west to Afghanistan on the east. (From Webster's New Geographical Dictionary, 1988)Cultural Competency: Cultural and linguistic competence is a set of congruent behaviors, attitudes, and policies that come together in a system, agency, or among professionals that enables effective work in cross-cultural situations. Competence implies the capacity to function effectively as an individual and an organization within the context of the cultural beliefs, behaviors, and needs presented by consumers and their communities.CaliforniaTurkeyHealthcare Disparities: Differences in access to or availability of medical facilities and services.Population Groups: Individuals classified according to their sex, racial origin, religion, common place of living, financial or social status, or some other cultural or behavioral attribute. (UMLS, 2003)Health Status Disparities: Variation in rates of disease occurrence and disabilities between population groups defined by socioeconomic characteristics such as age, ethnicity, economic resources, or gender and populations identified geographically or similar measures.Residence Characteristics: Elements of residence that characterize a population. They are applicable in determining need for and utilization of health services.Social Welfare: Organized institutions which provide services to ameliorate conditions of need or social pathology in the community.Islam: A monotheistic religion promulgated by the Prophet Mohammed with Allah as the deity.Cell Proliferation: All of the processes involved in increasing CELL NUMBER including CELL DIVISION.El SalvadorLogistic Models: Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.Interviews as Topic: Conversations with an individual or individuals held in order to obtain information about their background and other personal biographical data, their attitudes and opinions, etc. It includes school admission or job interviews.SwedenTuberculosis: Any of the infectious diseases of man and other animals caused by species of MYCOBACTERIUM.Multilingualism: The ability to speak, read, or write several languages or many languages with some facility. Bilingualism is the most common form. (From Random House Unabridged Dictionary, 2d ed)PhilippinesHealth Surveys: A systematic collection of factual data pertaining to health and disease in a human population within a given geographic area.United States Government Agencies: Agencies of the FEDERAL GOVERNMENT of the United States.Mass Screening: Organized periodic procedures performed on large groups of people for the purpose of detecting disease.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Travel: Aspects of health and disease related to travel.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Censuses: Enumerations of populations usually recording identities of all persons in every place of residence with age or date of birth, sex, occupation, national origin, language, marital status, income, relation to head of household, information on the dwelling place, education, literacy, health-related data (e.g., permanent disability), etc. The census or "numbering of the people" is mentioned several times in the Old Testament. Among the Romans, censuses were intimately connected with the enumeration of troops before and after battle and probably a military necessity. (From Last, A Dictionary of Epidemiology, 3d ed; Garrison, An Introduction to the History of Medicine, 4th ed, p66, p119)PakistanArabs: Members of a Semitic people inhabiting the Arabian peninsula or other countries of the Middle East and North Africa. The term may be used with reference to ancient, medieval, or modern ethnic or cultural groups. (From Random House Unabridged Dictionary, 2d ed)Health Status: The level of health of the individual, group, or population as subjectively assessed by the individual or by more objective measures.Cross-Cultural Comparison: Comparison of various psychological, sociological, or cultural factors in order to assess the similarities or diversities occurring in two or more different cultures or societies.Prejudice: A preconceived judgment made without factual basis.Questionnaires: Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.Patient Acceptance of Health Care: The seeking and acceptance by patients of health service.Cuba: An island in the Greater Antilles in the West Indies, south of Florida. With the adjacent islands it forms the Republic of Cuba. Its capital is Havana. It was discovered by Columbus on his first voyage in 1492 and conquered by Spain in 1511. It has a varied history under Spain, Great Britain, and the United States but has been independent since 1902. The name Cuba is said to be an Indian name of unknown origin but the language that gave the name is extinct, so the etymology is a conjecture. (From Webster's New Geographical Dictionary, 1988, p302 & Room, Brewer's Dictionary of Names, 1992, p132)Netherlands: Country located in EUROPE. It is bordered by the NORTH SEA, BELGIUM, and GERMANY. Constituent areas are Aruba, Curacao, Sint Maarten, formerly included in the NETHERLANDS ANTILLES.Asia, Southeastern: The geographical area of Asia comprising BORNEO; BRUNEI; CAMBODIA; INDONESIA; LAOS; MALAYSIA; the MEKONG VALLEY; MYANMAR (formerly Burma), the PHILIPPINES; SINGAPORE; THAILAND; and VIETNAM.Health Knowledge, Attitudes, Practice: Knowledge, attitudes, and associated behaviors which pertain to health-related topics such as PATHOLOGIC PROCESSES or diseases, their prevention, and treatment. This term refers to non-health workers and health workers (HEALTH PERSONNEL).Transcultural Nursing: A nursing specialty created to answer the need for developing a global perspective in the practice of nursing in a world of interdependent nations and people. The focus of this nursing discipline is on the integration of international and transcultural content into the training. Courses include study in the area of cultural differences, nursing in other countries, and international health issues and organizations, as an example.Educational Status: Educational attainment or level of education of individuals.Poverty: A situation in which the level of living of an individual, family, or group is below the standard of the community. It is often related to a specific income level.China: A country spanning from central Asia to the Pacific Ocean.LuxembourgChild Guidance: The psychiatric, sociological and psychological study and treatment of the developing child with emphasis on preventive or prophylactic measures focused on the familial, educational and socio-environmental milieu of the child.ItalyDemography: Statistical interpretation and description of a population with reference to distribution, composition, or structure.Ontario: A province of Canada lying between the provinces of Manitoba and Quebec. Its capital is Toronto. It takes its name from Lake Ontario which is said to represent the Iroquois oniatariio, beautiful lake. (From Webster's New Geographical Dictionary, 1988, p892 & Room, Brewer's Dictionary of Names, 1992, p391)ChileFamily Relations: Behavioral, psychological, and social relations among various members of the nuclear family and the extended family.Ethnopsychology: Comparative PSYCHOLOGY of different ethnic and cultural groups.Public Assistance: Financial assistance to impoverished persons for the essentials of living through federal, state or local government programs.Cultural Diversity: Coexistence of numerous distinct ethnic, racial, religious, or cultural groups within one social unit, organization, or population. (From American Heritage Dictionary, 2d college ed., 1982, p955)Eligibility Determination: Criteria to determine eligibility of patients for medical care programs and services.Strongyloidiasis: Infection with nematodes of the genus STRONGYLOIDES. The presence of larvae may produce pneumonitis and the presence of adult worms in the intestine could lead to moderate to severe diarrhea.Social Values: Abstract standards or empirical variables in social life which are believed to be important and/or desirable.IraqMedically Uninsured: Individuals or groups with no or inadequate health insurance coverage. Those falling into this category usually comprise three primary groups: the medically indigent (MEDICAL INDIGENCY); those whose clinical condition makes them medically uninsurable; and the working uninsured.Community-Based Participatory Research: Collaborative process of research involving researchers and community representatives.EuropeDominican Republic: A republic in the Greater Antilles in the West Indies. Its capital is Santo Domingo. With Haiti, it forms the island of Hispaniola - the Dominican Republic occupying the eastern two thirds, and Haiti, the western third. It was created in 1844 after a revolt against the rule of President Boyer over the entire island of Hispaniola, itself visited by Columbus in 1492 and settled the next year. Except for a brief period of annexation to Spain (1861-65), it has been independent, though closely associated with the United States. Its name comes from the Spanish Santo Domingo, Holy Sunday, with reference to its discovery on a Sunday. (From Webster's New Geographical Dictionary, 1988, p338, 506 & Room, Brewer's Dictionary of Names, 1992, p151)Social Class: A stratum of people with similar position and prestige; includes social stratification. Social class is measured by criteria such as education, occupation, and income.Mental Health: The state wherein the person is well adjusted.Focus Groups: A method of data collection and a QUALITATIVE RESEARCH tool in which a small group of individuals are brought together and allowed to interact in a discussion of their opinions about topics, issues, or questions.Africa, Eastern: The geographical area of Africa comprising BURUNDI; DJIBOUTI; ETHIOPIA; KENYA; RWANDA; SOMALIA; SUDAN; TANZANIA; and UGANDA.Mothers: Female parents, human or animal.Ethiopia: An independent state in eastern Africa. Ethiopia is located in the Horn of Africa and is bordered on the north and northeast by Eritrea, on the east by Djibouti and Somalia, on the south by Kenya, and on the west and southwest by Sudan. Its capital is Addis Ababa.