Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Dose-Response Relationship, Radiation: The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.Neoplasms, Radiation-Induced: Tumors, cancer or other neoplasms produced by exposure to ionizing or non-ionizing radiation.Arsenic: A shiny gray element with atomic symbol As, atomic number 33, and atomic weight 75. It occurs throughout the universe, mostly in the form of metallic arsenides. Most forms are toxic. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), arsenic and certain arsenic compounds have been listed as known carcinogens. (From Merck Index, 11th ed)Environmental Exposure: The exposure to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals.Time Factors: Elements of limited time intervals, contributing to particular results or situations.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.Smoking: Inhaling and exhaling the smoke of burning TOBACCO.Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.Occupational Exposure: The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation.Neuromuscular Nondepolarizing Agents: Drugs that interrupt transmission at the skeletal neuromuscular junction without causing depolarization of the motor end plate. They prevent acetylcholine from triggering muscle contraction and are used as muscle relaxants during electroshock treatments, in convulsive states, and as anesthesia adjuvants.No-Observed-Adverse-Effect Level: The highest dosage administered that does not produce toxic effects.Water Pollutants, Chemical: Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.Carcinogens: Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.Arsenic Poisoning: Disorders associated with acute or chronic exposure to compounds containing ARSENIC (ARSENICALS) which may be fatal. Acute oral ingestion is associated with gastrointestinal symptoms and an encephalopathy which may manifest as SEIZURES, mental status changes, and COMA. Chronic exposure is associated with mucosal irritation, desquamating rash, myalgias, peripheral neuropathy, and white transverse (Mees) lines in the fingernails. (Adams et al., Principles of Neurology, 6th ed, p1212)Risk Assessment: The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)Body Burden: The total amount of a chemical, metal or radioactive substance present at any time after absorption in the body of man or animal.Occupational Diseases: Diseases caused by factors involved in one's employment.Risk: The probability that an event will occur. It encompasses a variety of measures of the probability of a generally unfavorable outcome.Nuclear Warfare: Warfare involving the use of NUCLEAR WEAPONS.Androstanols: Androstanes and androstane derivatives which are substituted in any position with one or more hydroxyl groups.Cohort Studies: Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.Odds Ratio: The ratio of two odds. The exposure-odds ratio for case control data is the ratio of the odds in favor of exposure among cases to the odds in favor of exposure among noncases. The disease-odds ratio for a cohort or cross section is the ratio of the odds in favor of disease among the exposed to the odds in favor of disease among the unexposed. The prevalence-odds ratio refers to an odds ratio derived cross-sectionally from studies of prevalent cases.Neuromuscular Blocking Agents: Drugs that interrupt transmission of nerve impulses at the skeletal neuromuscular junction. They can be of two types, competitive, stabilizing blockers (NEUROMUSCULAR NONDEPOLARIZING AGENTS) or noncompetitive, depolarizing agents (NEUROMUSCULAR DEPOLARIZING AGENTS). Both prevent acetylcholine from triggering the muscle contraction and they are used as anesthesia adjuvants, as relaxants during electroshock, in convulsive states, etc.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Mutagens: Chemical agents that increase the rate of genetic mutation by interfering with the function of nucleic acids. A clastogen is a specific mutagen that causes breaks in chromosomes.Atracurium: A non-depolarizing neuromuscular blocking agent with short duration of action. Its lack of significant cardiovascular effects and its lack of dependence on good kidney function for elimination provide clinical advantage over alternate non-depolarizing neuromuscular blocking agents.Benzene: Toxic, volatile, flammable liquid hydrocarbon byproduct of coal distillation. It is used as an industrial solvent in paints, varnishes, lacquer thinners, gasoline, etc. Benzene causes central nervous system damage acutely and bone marrow damage chronically and is carcinogenic. It was formerly used as parasiticide.Water Supply: Means or process of supplying water (as for a community) usually including reservoirs, tunnels, and pipelines and often the watershed from which the water is ultimately drawn. (Webster, 3d ed)Ethylene Oxide: A colorless and flammable gas at room temperature and pressure. Ethylene oxide is a bactericidal, fungicidal, and sporicidal disinfectant. It is effective against most micro-organisms, including viruses. It is used as a fumigant for foodstuffs and textiles and as an agent for the gaseous sterilization of heat-labile pharmaceutical and surgical materials. (From Reynolds, Martindale The Extra Pharmacopoeia, 30th ed, p794)Tetrachlorodibenzodioxin: A chemical by-product that results from burning or incinerating chlorinated industrial chemicals and other hydrocarbons. This compound is considered an environmental toxin, and may pose reproductive, as well as, other health risks for animals and humans.Chernobyl Nuclear Accident: April 25th -26th, 1986 nuclear power accident that occurred at Chernobyl in the former USSR (Ukraine) located 80 miles north of Kiev.Dose-Response Relationship, Immunologic: A specific immune response elicited by a specific dose of an immunologically active substance or cell in an organism, tissue, or cell.Gamma Rays: Penetrating, high-energy electromagnetic radiation emitted from atomic nuclei during NUCLEAR DECAY. The range of wavelengths of emitted radiation is between 0.1 - 100 pm which overlaps the shorter, more energetic hard X-RAYS wavelengths. The distinction between gamma rays and X-rays is based on their radiation source.Air Pollutants, Occupational: Air pollutants found in the work area. They are usually produced by the specific nature of the occupation.Environmental Pollutants: Substances or energies, for example heat or light, which when introduced into the air, water, or land threaten life or health of individuals or ECOSYSTEMS.TaiwanEdrophonium: A rapid-onset, short-acting cholinesterase inhibitor used in cardiac arrhythmias and in the diagnosis of myasthenia gravis. It has also been used as an antidote to curare principles.Environmental Monitoring: The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.Micronuclei, Chromosome-Defective: Defective nuclei produced during the TELOPHASE of MITOSIS or MEIOSIS by lagging CHROMOSOMES or chromosome fragments derived from spontaneous or experimentally induced chromosomal structural changes.PaintNeuromuscular Blockade: The intentional interruption of transmission at the NEUROMUSCULAR JUNCTION by external agents, usually neuromuscular blocking agents. It is distinguished from NERVE BLOCK in which nerve conduction (NEURAL CONDUCTION) is interrupted rather than neuromuscular transmission. Neuromuscular blockade is commonly used to produce MUSCLE RELAXATION as an adjunct to anesthesia during surgery and other medical procedures. It is also often used as an experimental manipulation in basic research. It is not strictly speaking anesthesia but is grouped here with anesthetic techniques. The failure of neuromuscular transmission as a result of pathological processes is not included here.Alcohol Drinking: Behaviors associated with the ingesting of alcoholic beverages, including social drinking.Logistic 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.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Dust: Earth or other matter in fine, dry particles. (Random House Unabridged Dictionary, 2d ed)Maximum Allowable Concentration: The maximum exposure to a biologically active physical or chemical agent that is allowed during an 8-hour period (a workday) in a population of workers, or during a 24-hour period in the general population, which does not appear to cause appreciable harm, whether immediate or delayed for any period, in the target population. (From Lewis Dictionary of Toxicology, 1st ed)Administration, Inhalation: The administration of drugs by the respiratory route. It includes insufflation into the respiratory tract.Radiometry: The measurement of radiation by photography, as in x-ray film and film badge, by Geiger-Mueller tube, and by SCINTILLATION COUNTING.Inhalation Exposure: The exposure to potentially harmful chemical, physical, or biological agents by inhaling them.Regression Analysis: Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.Carcinogens, Environmental: Carcinogenic substances that are found in the environment.Epidemiological Monitoring: Collection, analysis, and interpretation of data about the frequency, distribution, and consequences of disease or health conditions, for use in the planning, implementing, and evaluating public health programs.Tobacco Smoke Pollution: Contamination of the air by tobacco smoke.Metallurgy: The science, art, or technology dealing with processes involved in the separation of metals from their ores, the technique of making or compounding the alloys, the techniques of working or heat-treating metals, and the mining of metals. It includes industrial metallurgy as well as metallurgical techniques employed in the preparation and working of metals used in dentistry, with special reference to orthodontic and prosthodontic appliances. (From Jablonski, Dictionary of Dentistry, 1992, p494)Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Neostigmine: A cholinesterase inhibitor used in the treatment of myasthenia gravis and to reverse the effects of muscle relaxants such as gallamine and tubocurarine. Neostigmine, unlike PHYSOSTIGMINE, does not cross the blood-brain barrier.JapanNeuromuscular Junction: The synapse between a neuron and a muscle.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.Micronucleus Tests: Induction and quantitative measurement of chromosomal damage leading to the formation of micronuclei (MICRONUCLEI, CHROMOSOME-DEFECTIVE) in cells which have been exposed to genotoxic agents or IONIZING RADIATION.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Vecuronium Bromide: Monoquaternary homolog of PANCURONIUM. A non-depolarizing neuromuscular blocking agent with shorter duration of action than pancuronium. Its lack of significant cardiovascular effects and lack of dependence on good kidney function for elimination as well as its short duration of action and easy reversibility provide advantages over, or alternatives to, other established neuromuscular blocking agents.Polycyclic Hydrocarbons, Aromatic: A major group of unsaturated cyclic hydrocarbons containing two or more rings. The vast number of compounds of this important group, derived chiefly from petroleum and coal tar, are rather highly reactive and chemically versatile. The name is due to the strong and not unpleasant odor characteristic of most substances of this nature. (From Hawley's Condensed Chemical Dictionary, 12th ed, p96)Lung Neoplasms: Tumors or cancer of the LUNG.Drug Interactions: The action of a drug that may affect the activity, metabolism, or toxicity of another drug.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.China: A country spanning from central Asia to the Pacific Ocean.Nitrous Oxide: Nitrogen oxide (N2O). A colorless, odorless gas that is used as an anesthetic and analgesic. High concentrations cause a narcotic effect and may replace oxygen, causing death by asphyxia. It is also used as a food aerosol in the preparation of whipping cream.Neoplasms: New abnormal growth of tissue. Malignant neoplasms show a greater degree of anaplasia and have the properties of invasion and metastasis, compared to benign neoplasms.Diethylnitrosamine: A nitrosamine derivative with alkylating, carcinogenic, and mutagenic properties.Radiation Dosage: The amount of radiation energy that is deposited in a unit mass of material, such as tissues of plants or animal. In RADIOTHERAPY, radiation dosage is expressed in gray units (Gy). In RADIOLOGIC HEALTH, the dosage is expressed by the product of absorbed dose (Gy) and quality factor (a function of linear energy transfer), and is called radiation dose equivalent in sievert units (Sv).Diet: Regular course of eating and drinking adopted by a person or animal.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.Confidence Intervals: A range of values for a variable of interest, e.g., a rate, constructed so that this range has a specified probability of including the true value of the variable.Rats, Inbred Strains: Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.Air Pollutants: Any substance in the air which could, if present in high enough concentration, harm humans, animals, vegetation or material. Substances include GASES; PARTICULATE MATTER; and volatile ORGANIC CHEMICALS.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.Water Pollutants: Substances or organisms which pollute the water or bodies of water. Use for water pollutants in general or those for which there is no specific heading.Lead: A soft, grayish metal with poisonous salts; atomic number 82, atomic weight 207.19, symbol Pb. (Dorland, 28th)Toxicity Tests: An array of tests used to determine the toxicity of a substance to living systems. These include tests on clinical drugs, foods, and environmental pollutants.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.Asthma: A form of bronchial disorder with three distinct components: airway hyper-responsiveness (RESPIRATORY HYPERSENSITIVITY), airway INFLAMMATION, and intermittent AIRWAY OBSTRUCTION. It is characterized by spasmodic contraction of airway smooth muscle, WHEEZING, and dyspnea (DYSPNEA, PAROXYSMAL).Prenatal Exposure Delayed Effects: The consequences of exposing the FETUS in utero to certain factors, such as NUTRITION PHYSIOLOGICAL PHENOMENA; PHYSIOLOGICAL STRESS; DRUGS; RADIATION; and other physical or chemical factors. These consequences are observed later in the offspring after BIRTH.Administration, Oral: The giving of drugs, chemicals, or other substances by mouth.Mutagenicity Tests: Tests of chemical substances and physical agents for mutagenic potential. They include microbial, insect, mammalian cell, and whole animal tests.Drug Administration Schedule: Time schedule for administration of a drug in order to achieve optimum effectiveness and convenience.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.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.Hair: A filament-like structure consisting of a shaft which projects to the surface of the SKIN from a root which is softer than the shaft and lodges in the cavity of a HAIR FOLLICLE. It is found on most surfaces of the body.Industry: Any enterprise centered on the processing, assembly, production, or marketing of a line of products, services, commodities, or merchandise, in a particular field often named after its principal product. Examples include the automobile, fishing, music, publishing, insurance, and textile industries.Asbestos: Asbestos. Fibrous incombustible mineral composed of magnesium and calcium silicates with or without other elements. It is relatively inert chemically and used in thermal insulation and fireproofing. Inhalation of dust causes asbestosis and later lung and gastrointestinal neoplasms.Data Interpretation, Statistical: Application of statistical procedures to analyze specific observed or assumed facts from a particular study.DNA Adducts: The products of chemical reactions that result in the addition of extraneous chemical groups to DNA.Liver Neoplasms, Experimental: Experimentally induced tumors of the LIVER.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Linear Models: Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.Confounding Factors (Epidemiology): Factors that can cause or prevent the outcome of interest, are not intermediate variables, and are not associated with the factor(s) under investigation. They give rise to situations in which the effects of two processes are not separated, or the contribution of causal factors cannot be separated, or the measure of the effect of exposure or risk is distorted because of its association with other factors influencing the outcome of the study.Coffee: A beverage made from ground COFFEA beans (SEEDS) infused in hot water. It generally contains CAFFEINE and THEOPHYLLINE unless it is decaffeinated.Comet Assay: A genotoxicological technique for measuring DNA damage in an individual cell using single-cell gel electrophoresis. Cell DNA fragments assume a "comet with tail" formation on electrophoresis and are detected with an image analysis system. Alkaline assay conditions facilitate sensitive detection of single-strand damage.Cocarcinogenesis: The combination of two or more different factors in the production of cancer.Sex Factors: Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.Epidemiologic Studies: Studies designed to examine associations, commonly, hypothesized causal relations. They are usually concerned with identifying or measuring the effects of risk factors or exposures. The common types of analytic study are CASE-CONTROL STUDIES; COHORT STUDIES; and CROSS-SECTIONAL STUDIES.Tea: The infusion of leaves of CAMELLIA SINENSIS (formerly Thea sinensis) as a beverage, the familiar Asian tea, which contains CATECHIN (especially epigallocatechin gallate) and CAFFEINE.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Kinetics: The rate dynamics in chemical or physical systems.Radiotherapy Dosage: The total amount of radiation absorbed by tissues as a result of radiotherapy.Biological Assay: A method of measuring the effects of a biologically active substance using an intermediate in vivo or in vitro tissue or cell model under controlled conditions. It includes virulence studies in animal fetuses in utero, mouse convulsion bioassay of insulin, quantitation of tumor-initiator systems in mouse skin, calculation of potentiating effects of a hormonal factor in an isolated strip of contracting stomach muscle, etc.Drug Synergism: The action of a drug in promoting or enhancing the effectiveness of another drug.Rats, Inbred F344Body Weight: The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.Lymphocytes: White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.Chemical Industry: The aggregate enterprise of manufacturing and technically producing chemicals. (From Random House Unabridged Dictionary, 2d ed)Infusions, Intravenous: The long-term (minutes to hours) administration of a fluid into the vein through venipuncture, either by letting the fluid flow by gravity or by pumping it.Halothane: A nonflammable, halogenated, hydrocarbon anesthetic that provides relatively rapid induction with little or no excitement. Analgesia may not be adequate. NITROUS OXIDE is often given concomitantly. Because halothane may not produce sufficient muscle relaxation, supplemental neuromuscular blocking agents may be required. (From AMA Drug Evaluations Annual, 1994, p178)United StatesAflatoxin B1: A potent hepatotoxic and hepatocarcinogenic mycotoxin produced by the Aspergillus flavus group of fungi. It is also mutagenic, teratogenic, and causes immunosuppression in animals. It is found as a contaminant in peanuts, cottonseed meal, corn, and other grains. The mycotoxin requires epoxidation to aflatoxin B1 2,3-oxide for activation. Microsomal monooxygenases biotransform the toxin to the less toxic metabolites aflatoxin M1 and Q1.DNA Damage: Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Organ Size: The measurement of an organ in volume, mass, or heaviness.Motor Activity: The physical activity of a human or an animal as a behavioral phenomenon.Models, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Maternal Exposure: Exposure of the female parent, human or animal, to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals that may affect offspring. It includes pre-conception maternal exposure.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Random Allocation: A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.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.Placebos: Any dummy medication or treatment. Although placebos originally were medicinal preparations having no specific pharmacological activity against a targeted condition, the concept has been extended to include treatments or procedures, especially those administered to control groups in clinical trials in order to provide baseline measurements for the experimental protocol.Neoplasms, Experimental: Experimentally induced new abnormal growth of TISSUES in animals to provide models for studying human neoplasms.Stimulation, Chemical: The increase in a measurable parameter of a PHYSIOLOGICAL PROCESS, including cellular, microbial, and plant; immunological, cardiovascular, respiratory, reproductive, urinary, digestive, neural, musculoskeletal, ocular, and skin physiological processes; or METABOLIC PROCESS, including enzymatic and other pharmacological processes, by a drug or other chemical.Proportional Hazards Models: Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study population is multiplicative and does not change over time.Morphine: The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle.Analgesics: Compounds capable of relieving pain without the loss of CONSCIOUSNESS.Cross-Over Studies: Studies comparing two or more treatments or interventions in which the subjects or patients, upon completion of the course of one treatment, are switched to another. In the case of two treatments, A and B, half the subjects are randomly allocated to receive these in the order A, B and half to receive them in the order B, A. A criticism of this design is that effects of the first treatment may carry over into the period when the second is given. (Last, A Dictionary of Epidemiology, 2d ed)Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Acetylcholine: A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.BangladeshMethyl Ethers: A group of compounds that contain the general formula R-OCH3.Skin Neoplasms: Tumors or cancer of the SKIN.Infant, Newborn: An infant during the first month after birth.Randomized Controlled Trials as Topic: Works about clinical trials that involve at least one test treatment and one control treatment, concurrent enrollment and follow-up of the test- and control-treated groups, and in which the treatments to be administered are selected by a random process, such as the use of a random-numbers table.Exercise: Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.Radiation, Ionizing: ELECTROMAGNETIC RADIATION or particle radiation (high energy ELEMENTARY PARTICLES) capable of directly or indirectly producing IONS in its passage through matter. The wavelengths of ionizing electromagnetic radiation are equal to or smaller than those of short (far) ultraviolet radiation and include gamma and X-rays.Sex Distribution: The number of males and females in a given population. The distribution may refer to how many men or women or what proportion of either in the group. The population is usually patients with a specific disease but the concept is not restricted to humans and is not restricted to medicine.Mice, Inbred Strains: Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations, or by parent x offspring matings carried out with certain restrictions. All animals within an inbred strain trace back to a common ancestor in the twentieth generation.Multivariate Analysis: A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables.Anticonvulsants: Drugs used to prevent SEIZURES or reduce their severity.Respiratory Tract DiseasesRunning: An activity in which the body is propelled by moving the legs rapidly. Running is performed at a moderate to rapid pace and should be differentiated from JOGGING, which is performed at a much slower pace.Aerosols: Colloids with a gaseous dispersing phase and either liquid (fog) or solid (smoke) dispersed phase; used in fumigation or in inhalation therapy; may contain propellant agents.Body Mass Index: An indicator of body density as determined by the relationship of BODY WEIGHT to BODY HEIGHT. BMI=weight (kg)/height squared (m2). BMI correlates with body fat (ADIPOSE TISSUE). Their relationship varies with age and gender. For adults, BMI falls into these categories: below 18.5 (underweight); 18.5-24.9 (normal); 25.0-29.9 (overweight); 30.0 and above (obese). (National Center for Health Statistics, Centers for Disease Control and Prevention)Isoquinolines: A group of compounds with the heterocyclic ring structure of benzo(c)pyridine. The ring structure is characteristic of the group of opium alkaloids such as papaverine. (From Stedman, 25th ed)Reference Values: The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.Epidemiologic Methods: Research techniques that focus on study designs and data gathering methods in human and animal populations.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Bias (Epidemiology): Any deviation of results or inferences from the truth, or processes leading to such deviation. Bias can result from several sources: one-sided or systematic variations in measurement from the true value (systematic error); flaws in study design; deviation of inferences, interpretations, or analyses based on flawed data or data collection; etc. There is no sense of prejudice or subjectivity implied in the assessment of bias under these conditions.Pain Measurement: Scales, questionnaires, tests, and other methods used to assess pain severity and duration in patients or experimental animals to aid in diagnosis, therapy, and physiological studies.Solvents: Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)Breast Neoplasms: Tumors or cancer of the human BREAST.Life Style: Typical way of life or manner of living characteristic of an individual or group. (From APA, Thesaurus of Psychological Index Terms, 8th ed)Cadmium: An element with atomic symbol Cd, atomic number 48, and atomic weight 114. It is a metal and ingestion will lead to CADMIUM POISONING.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Atropine: An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.Health Surveys: A systematic collection of factual data pertaining to health and disease in a human population within a given geographic area.Insulin: A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).GermanyRats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Norepinephrine: Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.Radiotherapy: The use of IONIZING RADIATION to treat malignant NEOPLASMS and some benign conditions.Forced Expiratory Volume: Measure of the maximum amount of air that can be expelled in a given number of seconds during a FORCED VITAL CAPACITY determination . It is usually given as FEV followed by a subscript indicating the number of seconds over which the measurement is made, although it is sometimes given as a percentage of forced vital capacity.Drug Evaluation, Preclinical: Preclinical testing of drugs in experimental animals or in vitro for their biological and toxic effects and potential clinical applications.Animals, Newborn: Refers to animals in the period of time just after birth.Survivors: Persons who have experienced a prolonged survival after serious disease or who continue to live with a usually life-threatening condition as well as family members, significant others, or individuals surviving traumatic life events.Urinary Bladder Neoplasms: Tumors or cancer of the URINARY BLADDER.Comorbidity: The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival.Longitudinal Studies: Studies in which variables relating to an individual or group of individuals are assessed over a period of time.Pain: An unpleasant sensation induced by noxious stimuli which are detected by NERVE ENDINGS of NOCICEPTIVE NEURONS.Guinea Pigs: A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.Models, Statistical: Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.Injections, Intravenous: Injections made into a vein for therapeutic or experimental purposes.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Chromosome Aberrations: Abnormal number or structure of chromosomes. Chromosome aberrations may result in CHROMOSOME DISORDERS.Potassium: An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.Iodine Radioisotopes: Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.Statistics as Topic: The science and art of collecting, summarizing, and analyzing data that are subject to random variation. The term is also applied to the data themselves and to the summarization of the data.Area Under Curve: A statistical means of summarizing information from a series of measurements on one individual. It is frequently used in clinical pharmacology where the AUC from serum levels can be interpreted as the total uptake of whatever has been administered. As a plot of the concentration of a drug against time, after a single dose of medicine, producing a standard shape curve, it is a means of comparing the bioavailability of the same drug made by different companies. (From Winslade, Dictionary of Clinical Research, 1992)Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.DenmarkSwine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Severity of Illness Index: Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.Half-Life: The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity.Socioeconomic Factors: Social and economic factors that characterize the individual or group within the social structure.Clinical Trials as Topic: Works about pre-planned studies of the safety, efficacy, or optimum dosage schedule (if appropriate) of one or more diagnostic, therapeutic, or prophylactic drugs, devices, or techniques selected according to predetermined criteria of eligibility and observed for predefined evidence of favorable and unfavorable effects. This concept includes clinical trials conducted both in the U.S. and in other countries.Membrane Potentials: The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).