Women's Health and Education Center (WHEC)


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Identical Twin: twins produced by the division of a single zygote; both have identical genotypes. See also -- fraternal twin.

Idiotypes: The unique and characteristic parts of an antibody's variable region, which can themselves, serve as antigens.

Immune: the state of being secure against harmful agents (e.g., bacteria, virus, or other foreign proteins) or influences.

Immune Clearance: clearance of antigen from the circulation after complexing with antibodies.

Immunotherapy: using the immune system to treat disease, for example, in the development of vaccines. May also refer to the therapy of diseases caused by the immune system. See also -- cancer.

Immune Response: a specific response that results in immunity. The total response includes an afferent phase during which responsive cells are "primed" by antigen, a central response during which antibodies or sensitized lymphoid cells are formed, and an efferent or effector response during which immunity is effected by antibodies or immune cells.

Immunity: the state of being able to resist or overcome harmful agents or influences. Active: Immunity acquired as the result of experience with an organism or other foreign substance. Passive: Immunity resulting from acquisition of antibody or sensitized lymphoid cells.

Immunize: the act or process of rendering an individual resistant or immune to a harmful agent.

Immunocompetent Cell (Antigen-sensitive Cell): any cell that can be stimulated by antigen to form antibodies or give rise to sensitized lymphoid cells, including inducible cells, primed cells, and memory cells.

Immunoconjugate: a monoclonal antibody linked to a chemotherapy agent, radioisotope, or natural toxin to increase ability to kill target cells.

Immunogen: an antigen that incites specific immunity.

Immunoglobulins: classes of globulins to which all antibodies belong.

Immunologic Enhancement: enhanced survival of incompatible tissue grafts (tumor or normal tissue) caused by specific humoral or other blocking factors.

Immunologic Paralysis: absence of normal specific immunologic response to an antigen, resulting from previous contact with the same antigen, administered in a quantity greatly exceeding that required to elicit an immunologic response. The normal capacity to respond to other unrelated antigens is retained.

Immunologic Surveillance: effective immunologic surveillance relies on the presence of tumor-specific antigenic determinants on the surfaces of neoplastic cells, which enable these altered cells to be recognized as non-self and to be destroyed by immunologic reactions.

Immunologic Tolerance: (antigenic paralysis, immunologic suppression, immunologic unresponsiveness, antigen tolerance) failure of the antibody response to a potential antigen after exposure to that antigen. Tolerance commonly results from prior exposure to antigens.

Immunoreaction: reaction between antigen and its antibody.

Immunotoxin: a monoclonal antibody linked to a natural toxin.

Impact: the total, direct and indirect, effects of a program, service or institution on a health status and overall health and socio-economic development.

Impact Assessment: impact assessment is about judging the effect that a policy or activity will have on people or places. It has been defined as the "prediction or estimation of the consequences of a current or proposed action" (Vanclay and Bronstein, 1995)

Impartial: not favoring a particular belief or point of view; unbiased.

Implantation: attachment of the balstocyst to the endometrial lining of the uterus and subsequent embedding in the endometrium. Implantation begins at about 5-7 days after fertilization and may be complete as early as 8-9 days after fertilization.

Implementation: the carrying out of a project or program.

Imprinting: the imposition of a stable behavior pattern in a young animal by exposure, during a particular period in its development, to one of a restricted set of stimuli.

Imprinting (Genetics): a phenomenon in which the disease phenotype depends on which parent passed on the disease gene. For instance, both Prader-Willi and Angelman syndromes are inherited when the same part of chromosome 15 is missing. When the father's complement of 15 is missing, the child has Prader-Willi, but when the mother's complement of 15 is missing, the child has Angelman syndrome.

Incentives: systems which reward and therefore tend to encourage certain types of activity.

Incidence: occurrence, or the rate of occurrence. The number of instances of illness commencing or of persons falling ill, during a given period in a specified population. More generally, the number of new events, e.g., new cases of a disease in a defined population, within a specified period of time. The term incidence is sometimes used to denote INCIDENCE RATE.

Incidence Rate: measures the new cases of a specific disease that develop during a defined period of time and the approximation of the risk for developing the disease. The incidence rate focuses on events. Incidence measures the probability of developing a disease.

Incidence of Bacilloscopically Positive (BK+) Tuberculosis: the number of new cases of bacilloscopically confirmed tuberculosis, in a specific year, expressed per 100.000 population, for a given country, territory, or geographic area.

Incidence of Oral Cavity Cancer: incidence of oral cavity cancer (ICD-10: C00-C08). Age-standardized rate (ASR) per 100,000 world standard population.

Incidence Rate: the number of new cases of a disease in a defined population over a specified period of time.

Incontinence: accidental or involuntary loss of urine or feces (stool). A person may have urinary or fecal incontinence or both (sometimes called double incontinence).

Independent Variable: the independent variable is used to explain the dependent variable.

Index Admission: the first admission for the subject in the study period.

Index Patient: the original patient diagnosed for a particular infection.

Indicator: a variable with characteristics of quality, quantity and time used to measure, directly or indirectly, changes in a situation and to appreciate the progress made in addressing it. It also provides a basis for developing adequate plans for improvement. Variable susceptible of direct measurement that is assumed to be associated with a state that cannot be measured directly. Indicators are sometimes standardized by national or international authorities. Variable that helps to measure changes in a health situation directly or indirectly and to assess the extent to which the objectives and targets of a program are being attained. Markers for assessing and/or understanding a particular (social, economic, political, medical, etc.) phenomenon.

Indirect Methods: methods or questions that obscure the data collector's true intentions.

Induced Abortion: intentional termination of pregnancy prior to fetus reaching the state of viability by mechanical (surgical) means or by drugs. Provoked termination of pregnancy.

Indwelling Catheters: tube device inserted into the bladder to drain the urine continuously. Sometimes called a Foley catheter.

Indwelling Urethral Catheterization: process of inserting a tube device into the bladder through the urethra to drain urine continuously.

Inequalities Audit / Equity Audit: a review of inequalities within an area or of the coverage of inequalities issues in a policy, program or project, usually with recommendations as to how they can be addressed.

Inequality in Health: differences in health across individuals in the population.

Infant Mortality Rate (IMR): the quotient between the number of deaths in children under 1 year of age in a given year and the number of live births in that year, for a given country, territory, or geographic area, expressed per 1,000 live births, as reported from the national health authority. The reported neonatal mortality rate is defined as the quotient between the number of children born alive that died before the age of 28 days in a given year and the number of live births in that year, for a given country, territory, or geographic area, expressed per 1,000 live births, as reported from the national health authority. The reported post-neonatal mortality rate is defined as the quotient between the number of children that were alive after 27 days of age and died before the age of 1 year in a given year and the number of live births in that year, for a given country, territory, or geographic area, expressed per 1,000 live births, as reported from the national health authority. The estimated infant mortality rate is the quotient between the number of deaths in children under 1 year of age in a given year and the number of live births in that year, for a given country, territory, or geographic area, expressed per 1,000 live births, as estimated by the United Nations' Population Division.

Infertility: inability to conceive; usually assumed to exist if pregnancy is not achieved after 12 months of regular sexual intercourse, without the use of any form of birth control.

Infestation: development of a pathogenic agent on the body, e.g., body lice.

Inflation: Consumer Prices Index's Annual Growth Rate: the annual average rate of change in the cost, to the average consumer, of acquiring a defined basket of goods and services that may be fixed or changed at specific intervals, for a given national economy, during a one year period. Technical Note: Consumer price index is usually derived explicitly as the weighted arithmetic mean of the current prices of goods and services from the fixed basket, obtained through recurring price surveys, based on their fixed value-based weights for the base period (Laspeyres formula), which are also obtained from household expenditure surveys. Consumer price index growth rates are those estimated by the World Bank from the corresponding data in the United Nations's Systems of National Accounts using the least-squares method.

Informants: persons with special knowledge or insights based on experience, training, or social position.

Information Asymmetry: the difference in the amount of information available to the various parties to a transaction which does not place them on equal footing to strike a deal.

Informative: a term used to describe the situation when the two homologous chromosomes from an individual can be distinguished from one another at a given locus; heterozygous is an alternative term.

Informed Consent: the ethical practice of providing sufficient information for potential research subjects to make informed decisions about their participation in a research study; informed consent involves the presentation to the subjects of a statement of all the risks and benefits of participation.

Inner Cell Mass: the centrally located cells within the balstocyst; these cells will develop into the embryo.

Inpatient: a patient who is formally admitted (or "hospitalized") to an institution for treatment and/or care and stays for a minimum of one night in the hospital or other institution providing inpatient care.

Input: a quantified amount of a resource put in a process.

Insertion: a mutation caused by the presence of an additional sequence of nucleotide pairs in DNA. The addition of a DNA sequence into the genome.

In-Situ Hybridization: use of a DNA or RNA probe to detect the presence of the complementary DNA sequence in cloned bacterial or cultured eukaryotic cells.

Institution: an organization or association, established for the promotion of some object, especially one of public or general utility.

Instrumental Goal: a goal whose pursuit is really a means to another end.

Integrated Impact Assessment: integrated impact assessment brings together components of environmental, health, social and other forms of impact assessment in an attempt to incorporate an exploration of all the different ways in which policies, programs or projects may affect the physical, social and economic environment.

Integrated Model: compulsory or voluntary health insurance or third-party funding in which both the insurance and provision of health care is supplied by the same organization in a vertically integrated system.

Integrated Pollution Prevention Control Regulations: in October 1996 the European Commission published a Directive on Integrated Pollution Prevention and Control (IPPC) which came into effect on 30 October 1999. As a result, European Union Member States were required to introduce a regulatory system to ensure that particular industries take action to ensure "an integrated approach to pollution control" in order to achieve "a high level of protection for the environment as a whole" when considering both routine and accidental releases. The definition of pollution in the Directive includes releases to air, land or water "which may be harmful to human health". In the UK, Pollution Prevention and Control regulations were introduced in 2000 and they require that health authorities are consulted on IPPC. Three are around 7,000 sites affected across the country and the types of activity which are covered by the regulations include the energy, metals, oil, chemical and waste management industries, paper production, food production and some intensive livestock rearing (University of Birmingham, 2002).

Integrated Services: availability of multiple health services—for instance, family planning and STI treatment—through a single facility or at a single visit.

Integration: incorporation of other services into already existing services.

Intellectual Property Rights (IPR): these are exclusive rights, often temporary, granted by the state for the exploitation of intellectual creations. Intellectual property rights fall into two categories: rights relating to industrial property (invention patents, industrial designs and models, trademarks and geographical indications) and those relating to literary and artistic property (copyright). The Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS) covers the main categories of intellectual property law.

Interferon: a family of proteins released by cells in response to a virus infection. These substances represent non-specific immunity and appear to have non-specific tumoricidal characteristics.

Interleukin--1: a macrophage-derived cytokine that is necessary for the initial step in activation of specific T cells and the process of in vivo production of effector T cells.

Interleukin--2: a lymphokine with multiple in vitro and in vivo effects. It is an essential factor for the growth of T cells; it augments various T cell functions; it supports the preservation and augmentation of NK cell function; and it is critical for the generation of LAK cells.

Interleukins: polypeptides secreted by lymphocytes, monocytes, or other accessory cells that function in the regulation of the hematopoietic or immune system; these molecules have an important role in cell-to-cell communication.

Intermediate HIA Monitoring and Evaluation: an intermediate HIA may combine a workshop with key stakeholders followed by desk based work to build up a more detailed picture of the potential health impacts than those which would be identified during a rapid or "mini" HIA. It may involve a limited literature search, usually non-systematic, and is mostly reliant on routine, readily available data (Parry and Stevens, 2001).

Intermittent Catheterization: the use of catheters inserted through the urethra into the bladder every 3-6 hours for bladder drainage in persons with urinary retention. Intermittent catheterization performed by the patient at home is called clean intermittent catheterization (CIC).

Internal Validity: the index and comparison groups are selected and compared in such a manner that the observed differences between them on the dependent variables under study may, apart from sampling error, be attributed only to the hypothesized effect under investigation.

Intersectoral Action: action in which the health sector and other relevant sectors of the economy collaborate, or interact to pursue health goals.

International Law: This is the body of rules that are binding on states and other subjects of international law, in particular international organizations, in their relations with each other. Closely related to the concept of sovereignty of states, the norms of international law are binding because states consent that they should be. The expression of this consent appears from the actual practice of states in the case of customary international law and from ratifications in the case of treaties, to which the concept of pacta sunt servanda applies. This asserts that treaties are binding on the parties to them and must be executed in good faith. To the extent that the rules of international law influence the behavior of states in world politics, they are a "social reality", thus constituting an institution of "international society", or proof of the existence of an international community.

Intervention: an activity or set of activities aimed at modifying a process, course of action or sequence of events, in order to change one or several of their characteristics such as performance or expected outcome.

Interview Protocol: standard list of questions together with guidance on how to classify responses.

Intervention Research: also called operations research; research that includes design, implementation, and assessment of a service-delivery or community intervention.

Intrauterine Growth Restriction: estimated fetal weight less than the 10th percentile. The term intrauterine growth restriction includes normal fetuses at the lower end of the growth spectrum, as well as those specific clinical conditions in which the fetus fails to achieve its inherent growth potential as a consequence of either pathologic extrinsic influences (such as maternal smoking) or intrinsic genetic defects (such as aneuploidy). Distinctions between normal and pathologic growth often cannot be made reliably in clinical practice, especially before birth.

Intravesical Pressure: pressure within the bladder.

Intrinsic Goal: a goal that is valued in and of itself.

Intrinsic Sphincter Deficiency (ISD): cause of stress urinary incontinence in which the urethral sphincter is unable to contract and generate sufficient resistance in the bladder, especially during stress maneuvers. ISD may be due to congenital sphincter weakness, such as myelomeningocele or epispadias, or it may be acquired subsequent to prostatectomy, trauma, radiation therapy, or sacral cord lesions.

Introitus: external vaginal opening.

Intron: a region of a gene, made up of non-coding DNA sequences that lies between exons. Portions of genomic DNA that are interspersed between exons and are transcribed along with the exons into Heteronuclear RNA.

Inverse Square Law: the intensity of radiation from a point varies inversely as the square of the distance from the source. Thus, the dose rate at 2 cm from a source is one fourth that at 1 cm. At 3 cm, the dose rate is one-ninth that at 1 cm.

Inversion: a mutation involving the removal of a DNA sequence, its rotation through 180 degrees, and its reinsertion in the same location.

In- Vitro: studies performed outside a living organism such as in a laboratory.

In- Vivo: studies carried out in living organisms.

Independent Assortment: during meiosis each of the two copies of a gene is distributed to the germ cells independently of the distribution of other genes. See also -- linkage.

Informatics: see -- bioinformatics.

Informed Consent: an individual willingly agrees to participate in an activity after first being advised of the risks and benefits. See also -- privacy.

Inherit: in genetics, to receive genetic material from parents through biological processes.

Inherited: see -- inherit.

Insertion: a chromosome abnormality in which a piece of DNA is incorporated into a gene and thereby disrupts the gene's normal function. See also -- chromosome, DNA, gene, mutation.

Insertional Mutation: see -- insertion.

Intellectual Property Rights: patents, copyrights, and trademarks. See also -- patent.

Interference: one crossover event inhibits the chances of another crossover event. Also known as positive interference. Negative interference increases the chance of a second crossover. See also -- crossing over.

Interphase: the period in the cell cycle when DNA is replicated in the nucleus; followed by mitosis.

Intron: DNA sequence that interrupts the protein-coding sequence of a gene; an intron is transcribed into RNA but is cut out of the message before it is translated into protein. See also -- exon.

Ionization: the removal of an electron from an atom, leaving a positively charged ion.

Ionizing Radiation: radiation capable of causing ionization.

Ischemia: it is impairment of blood flow to tissues either because of constriction or frank obstruction of a blood vessel.

Iso- : identical.

Isoantibody: the term used in blood grouping studies to designate an antibody formed by one individual that reacts with antigens of another individual of the same species. See also alloantibody.

Isoantigen: see alloantigen. The isoantigen is commonly used in hematology.

Isoenzyme: an enzyme performing the same function as another enzyme but having a different set of amino acids. The two enzymes may function at different speeds.

Isogeneic: see syngeneic.

Isograft: see syngraft.

Isoimmune: see alloimmune.

Isologous: see syngeneic.

Isotope: nuclides having an equal number of protons but a different number of neutrons (excitable situation).

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