Neoplasms, Radiation-Induced: Tumors, cancer or other neoplasms produced by exposure to ionizing or non-ionizing radiation.Radiation Injuries: Harmful effects of non-experimental exposure to ionizing or non-ionizing radiation in VERTEBRATES.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.Radiation Injuries, Experimental: Experimentally produced harmful effects of ionizing or non-ionizing RADIATION in CHORDATA animals.Radiation-Protective Agents: Drugs used to protect against ionizing radiation. They are usually of interest for use in radiation therapy but have been considered for other, e.g. military, purposes.Radiation Tolerance: The ability of some cells or tissues to survive lethal doses of IONIZING RADIATION. Tolerance depends on the species, cell type, and physical and chemical variables, including RADIATION-PROTECTIVE AGENTS and RADIATION-SENSITIZING AGENTS.Dose-Response Relationship, Radiation: The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.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.Leukemia, Radiation-Induced: Leukemia produced by exposure to IONIZING RADIATION or NON-IONIZING RADIATION.Radiation Pneumonitis: Inflammation of the lung due to harmful effects of ionizing or non-ionizing radiation.X-Rays: Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard X-rays are the higher energy, shorter wavelength X-rays. Soft x-rays or Grenz rays are less energetic and longer in wavelength. The short wavelength end of the X-ray spectrum overlaps the GAMMA RAYS wavelength range. The distinction between gamma rays and X-rays is based on their radiation source.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).Radiotherapy: The use of IONIZING RADIATION to treat malignant NEOPLASMS and some benign conditions.Radiation-Sensitizing Agents: Drugs used to potentiate the effectiveness of radiation therapy in destroying unwanted cells.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.Whole-Body Irradiation: Irradiation of the whole body with ionizing or non-ionizing radiation. It is applicable to humans or animals but not to microorganisms.Abnormalities, Radiation-Induced: Congenital changes in the morphology of organs produced by exposure to ionizing or non-ionizing radiation.Bystander Effect: The result of a positive or negative response (to drugs, for example) in one cell being passed onto other cells via the GAP JUNCTIONS or the intracellular milieu.Radiodermatitis: A cutaneous inflammatory reaction occurring as a result of exposure to ionizing radiation.Ultraviolet Rays: That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.Radiation: Emission or propagation of acoustic waves (SOUND), ELECTROMAGNETIC ENERGY waves (such as LIGHT; RADIO WAVES; GAMMA RAYS; or X-RAYS), or a stream of subatomic particles (such as ELECTRONS; NEUTRONS; PROTONS; or ALPHA PARTICLES).Apoptosis: One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA; (DNA FRAGMENTATION); at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.Chromosome Aberrations: Abnormal number or structure of chromosomes. Chromosome aberrations may result in CHROMOSOME DISORDERS.DNA Repair: The reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule which contained damaged regions. The major repair mechanisms are excision repair, in which defective regions in one strand are excised and resynthesized using the complementary base pairing information in the intact strand; photoreactivation repair, in which the lethal and mutagenic effects of ultraviolet light are eliminated; and post-replication repair, in which the primary lesions are not repaired, but the gaps in one daughter duplex are filled in by incorporation of portions of the other (undamaged) daughter duplex. Excision repair and post-replication repair are sometimes referred to as "dark repair" because they do not require light.Linear Energy Transfer: Rate of energy dissipation along the path of charged particles. In radiobiology and health physics, exposure is measured in kiloelectron volts per micrometer of tissue (keV/micrometer T).MercaptoethylaminesCesium Radioisotopes: Unstable isotopes of cesium that decay or disintegrate emitting radiation. Cs atoms with atomic weights of 123, 125-132, and 134-145 are radioactive cesium isotopes.Abnormalities, MultipleCobalt Radioisotopes: Unstable isotopes of cobalt that decay or disintegrate emitting radiation. Co atoms with atomic weights of 54-64, except 59, are radioactive cobalt isotopes.Radioactive Hazard Release: Uncontrolled release of radioactive material from its containment. This either threatens to, or does, cause exposure to a radioactive hazard. Such an incident may occur accidentally or deliberately.Tumor Suppressor Protein p53: Nuclear phosphoprotein encoded by the p53 gene (GENES, P53) whose normal function is to control CELL PROLIFERATION and APOPTOSIS. A mutant or absent p53 protein has been found in LEUKEMIA; OSTEOSARCOMA; LUNG CANCER; and COLORECTAL CANCER.Cell Survival: The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.Xerostomia: Decreased salivary flow.Mice, Inbred C57BLTime Factors: Elements of limited time intervals, contributing to particular results or situations.Amifostine: A phosphorothioate proposed as a radiation-protective agent. It causes splenic vasodilation and may block autonomic ganglia.Mice, Inbred C3HHeavy Ions: Positively-charged atomic nuclei that have been stripped of their electrons. These particles have one or more units of electric charge and a mass exceeding that of the Helium-4 nucleus (alpha particle).Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Stomatitis: INFLAMMATION of the soft tissues of the MOUTH, such as MUCOSA; PALATE; GINGIVA; and LIP.DNA Breaks, Double-Stranded: Interruptions in the sugar-phosphate backbone of DNA, across both strands adjacently.Ataxia Telangiectasia Mutated Proteins: A group of PROTEIN-SERINE-THREONINE KINASES which activate critical signaling cascades in double strand breaks, APOPTOSIS, and GENOTOXIC STRESS such as ionizing ultraviolet A light, thereby acting as a DNA damage sensor. These proteins play a role in a wide range of signaling mechanisms in cell cycle control.UkraineCell Line, Tumor: A cell line derived from cultured tumor cells.Alpha Particles: Positively charged particles composed of two protons and two NEUTRONS, i.e. equivalent to HELIUM nuclei, which are emitted during disintegration of heavy ISOTOPES. Alpha rays have very strong ionizing power, but weak penetrability.G2 Phase: The period of the CELL CYCLE following DNA synthesis (S PHASE) and preceding M PHASE (cell division phase). The CHROMOSOMES are tetraploid in this point.Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Karyotyping: Mapping of the KARYOTYPE of a cell.Cell Cycle: The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.Radiation ProtectionMagnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.DNA-Binding Proteins: Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.Cosmic Radiation: High-energy radiation or particles from extraterrestrial space that strike the earth, its atmosphere, or spacecraft and may create secondary radiation as a result of collisions with the atmosphere or spacecraft.Fibrosarcoma: A sarcoma derived from deep fibrous tissue, characterized by bundles of immature proliferating fibroblasts with variable collagen formation, which tends to invade locally and metastasize by the bloodstream. (Stedman, 25th ed)Dose Fractionation: Administration of the total dose of radiation (RADIATION DOSAGE) in parts, at timed intervals.DNA-Activated Protein Kinase: A serine-threonine protein kinase that, when activated by DNA, phosphorylates several DNA-binding protein substrates including the TUMOR SUPPRESSOR PROTEIN P53 and a variety of TRANSCRIPTION FACTORS.Radiation Genetics: A subdiscipline of genetics that studies RADIATION EFFECTS on the components and processes of biological inheritance.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.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Congenital Abnormalities: Malformations of organs or body parts during development in utero.Protein-Serine-Threonine Kinases: A group of enzymes that catalyzes the phosphorylation of serine or threonine residues in proteins, with ATP or other nucleotides as phosphate donors.Radiotherapy Dosage: The total amount of radiation absorbed by tissues as a result of radiotherapy.Mice, Hairless: Mutant strains of mice that produce little or no hair.Chromosome Disorders: Clinical conditions caused by an abnormal chromosome constitution in which there is extra or missing chromosome material (either a whole chromosome or a chromosome segment). (from Thompson et al., Genetics in Medicine, 5th ed, p429)Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Tumor Cells, Cultured: Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.Ataxia Telangiectasia: An autosomal recessive inherited disorder characterized by choreoathetosis beginning in childhood, progressive CEREBELLAR ATAXIA; TELANGIECTASIS of CONJUNCTIVA and SKIN; DYSARTHRIA; B- and T-cell immunodeficiency, and RADIOSENSITIVITY to IONIZING RADIATION. Affected individuals are prone to recurrent sinobronchopulmonary infections, lymphoreticular neoplasms, and other malignancies. Serum ALPHA-FETOPROTEINS are usually elevated. (Menkes, Textbook of Child Neurology, 5th ed, p688) The gene for this disorder (ATM) encodes a cell cycle checkpoint protein kinase and has been mapped to chromosome 11 (11q22-q23).Cell Cycle Proteins: Proteins that control the CELL DIVISION CYCLE. This family of proteins includes a wide variety of classes, including CYCLIN-DEPENDENT KINASES, mitogen-activated kinases, CYCLINS, and PHOSPHOPROTEIN PHOSPHATASES as well as their putative substrates such as chromatin-associated proteins, CYTOSKELETAL PROTEINS, and TRANSCRIPTION FACTORS.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Eye Abnormalities: Congenital absence of or defects in structures of the eye; may also be hereditary.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.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.Acute Radiation Syndrome: A condition caused by a brief whole body exposure to more than one sievert dose equivalent of radiation. Acute radiation syndrome is initially characterized by ANOREXIA; NAUSEA; VOMITING; but can progress to hematological, gastrointestinal, neurological, pulmonary, and other major organ dysfunction.Tumor Suppressor Proteins: Proteins that are normally involved in holding cellular growth in check. Deficiencies or abnormalities in these proteins may lead to unregulated cell growth and tumor development.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Radiometry: The measurement of radiation by photography, as in x-ray film and film badge, by Geiger-Mueller tube, and by SCINTILLATION COUNTING.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.Genes, p53: Tumor suppressor genes located on the short arm of human chromosome 17 and coding for the phosphoprotein p53.Nuclear Warfare: Warfare involving the use of NUCLEAR WEAPONS.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.Radiation Effects: The effects of ionizing and nonionizing radiation upon living organisms, organs and tissues, and their constituents, and upon physiologic processes. It includes the effect of irradiation on food, drugs, and chemicals.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.Thymus Neoplasms: Tumors or cancer of the THYMUS GLAND.Cell Death: The termination of the cell's ability to carry out vital functions such as metabolism, growth, reproduction, responsiveness, and adaptability.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.Head and Neck Neoplasms: Soft tissue tumors or cancer arising from the mucosal surfaces of the LIP; oral cavity; PHARYNX; LARYNX; and cervical esophagus. Other sites included are the NOSE and PARANASAL SINUSES; SALIVARY GLANDS; THYROID GLAND and PARATHYROID GLANDS; and MELANOMA and non-melanoma skin cancers of the head and neck. (from Holland et al., Cancer Medicine, 4th ed, p1651)Brain Neoplasms: Neoplasms of the intracranial components of the central nervous system, including the cerebral hemispheres, basal ganglia, hypothalamus, thalamus, brain stem, and cerebellum. Brain neoplasms are subdivided into primary (originating from brain tissue) and secondary (i.e., metastatic) forms. Primary neoplasms are subdivided into benign and malignant forms. In general, brain tumors may also be classified by age of onset, histologic type, or presenting location in the brain.In Situ Hybridization, Fluorescence: A type of IN SITU HYBRIDIZATION in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei.Proctitis: INFLAMMATION of the MUCOUS MEMBRANE of the RECTUM, the distal end of the large intestine (INTESTINE, LARGE).Radiotherapy, Conformal: Radiotherapy where there is improved dose homogeneity within the tumor and reduced dosage to uninvolved structures. The precise shaping of dose distribution is achieved via the use of computer-controlled multileaf collimators.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Syndrome: A characteristic symptom complex.Relative Biological Effectiveness: The ratio of radiation dosages required to produce identical change based on a formula comparing other types of radiation with that of gamma or roentgen rays.Genomic Instability: An increased tendency of the GENOME to acquire MUTATIONS when various processes involved in maintaining and replicating the genome are dysfunctional.Skin Neoplasms: Tumors or cancer of the SKIN.Combined Modality Therapy: The treatment of a disease or condition by several different means simultaneously or sequentially. Chemoimmunotherapy, RADIOIMMUNOTHERAPY, chemoradiotherapy, cryochemotherapy, and SALVAGE THERAPY are seen most frequently, but their combinations with each other and surgery are also used.Nuclear Proteins: Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.Salivary Glands: Glands that secrete SALIVA in the MOUTH. There are three pairs of salivary glands (PAROTID GLAND; SUBLINGUAL GLAND; SUBMANDIBULAR GLAND).Bone Marrow: The soft tissue filling the cavities of bones. Bone marrow exists in two types, yellow and red. Yellow marrow is found in the large cavities of large bones and consists mostly of fat cells and a few primitive blood cells. Red marrow is a hematopoietic tissue and is the site of production of erythrocytes and granular leukocytes. Bone marrow is made up of a framework of connective tissue containing branching fibers with the frame being filled with marrow cells.Cobalt Isotopes: Stable cobalt atoms that have the same atomic number as the element cobalt, but differ in atomic weight. Co-59 is a stable cobalt isotope.Intestinal Diseases: Pathological processes in any segment of the INTESTINE from DUODENUM to RECTUM.Antioxidants: Naturally occurring or synthetic substances that inhibit or retard the oxidation of a substance to which it is added. They counteract the harmful and damaging effects of oxidation in animal tissues.Power Plants: Units that convert some other form of energy into electrical energy.Oxidative Stress: A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).Erythema: Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of causes.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.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.Lung Neoplasms: Tumors or cancer of the LUNG.Breast Neoplasms: Tumors or cancer of the human BREAST.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.Histones: Small chromosomal proteins (approx 12-20 kD) possessing an open, unfolded structure and attached to the DNA in cell nuclei by ionic linkages. Classification into the various types (designated histone I, histone II, etc.) is based on the relative amounts of arginine and lysine in each.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Mitosis: A type of CELL NUCLEUS division by means of which the two daughter nuclei normally receive identical complements of the number of CHROMOSOMES of the somatic cells of the species.Mice, Nude: Mutant mice homozygous for the recessive gene "nude" which fail to develop a thymus. They are useful in tumor studies and studies on immune responses.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Radiobiology: Study of the scientific principles, mechanisms, and effects of the interaction of ionizing radiation with living matter. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Reactive Oxygen Species: Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of signal transduction and gene expression, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.Lymphoma: A general term for various neoplastic diseases of the lymphoid tissue.Cyclin-Dependent Kinase Inhibitor p21: A cyclin-dependent kinase inhibitor that mediates TUMOR SUPPRESSOR PROTEIN P53-dependent CELL CYCLE arrest. p21 interacts with a range of CYCLIN-DEPENDENT KINASES and associates with PROLIFERATING CELL NUCLEAR ANTIGEN and CASPASE 3.Cardiovascular Abnormalities: Congenital, inherited, or acquired anomalies of the CARDIOVASCULAR SYSTEM, including the HEART and BLOOD VESSELS.Pyrimidine Dimers: Dimers found in DNA chains damaged by ULTRAVIOLET RAYS. They consist of two adjacent PYRIMIDINE NUCLEOTIDES, usually THYMINE nucleotides, in which the pyrimidine residues are covalently joined by a cyclobutane ring. These dimers block DNA REPLICATION.Craniofacial Abnormalities: Congenital structural deformities, malformations, or other abnormalities of the cranium and facial bones.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.Salivary Gland DiseasesBase Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Mice, Transgenic: Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.Gene Deletion: A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.Neoplasms, Second Primary: Abnormal growths of tissue that follow a previous neoplasm but are not metastases of the latter. The second neoplasm may have the same or different histological type and can occur in the same or different organs as the previous neoplasm but in all cases arises from an independent oncogenic event. The development of the second neoplasm may or may not be related to the treatment for the previous neoplasm since genetic risk or predisposing factors may actually be the cause.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.Translocation, Genetic: A type of chromosome aberration characterized by CHROMOSOME BREAKAGE and transfer of the broken-off portion to another location, often to a different chromosome.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Cell Division: The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.Glioma: Benign and malignant central nervous system neoplasms derived from glial cells (i.e., astrocytes, oligodendrocytes, and ependymocytes). Astrocytes may give rise to astrocytomas (ASTROCYTOMA) or glioblastoma multiforme (see GLIOBLASTOMA). Oligodendrocytes give rise to oligodendrogliomas (OLIGODENDROGLIOMA) and ependymocytes may undergo transformation to become EPENDYMOMA; CHOROID PLEXUS NEOPLASMS; or colloid cysts of the third ventricle. (From Escourolle et al., Manual of Basic Neuropathology, 2nd ed, p21)Tumor Stem Cell Assay: A cytologic technique for measuring the functional capacity of tumor stem cells by assaying their activity. It is used primarily for the in vitro testing of antineoplastic agents.Mucositis: An INFLAMMATION of the MUCOSA with burning or tingling sensation. It is characterized by atrophy of the squamous EPITHELIUM, vascular damage, inflammatory infiltration, and ulceration. It usually occurs at the mucous lining of the MOUTH, the GASTROINTESTINAL TRACT or the airway due to chemical irritations, CHEMOTHERAPY, or radiation therapy (RADIOTHERAPY).Radiosurgery: A radiological stereotactic technique developed for cutting or destroying tissue by high doses of radiation in place of surgical incisions. It was originally developed for neurosurgery on structures in the brain and its use gradually spread to radiation surgery on extracranial structures as well. The usual rigid needles or probes of stereotactic surgery are replaced with beams of ionizing radiation directed toward a target so as to achieve local tissue destruction.Keratinocytes: Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Cell Proliferation: All of the processes involved in increasing CELL NUMBER including CELL DIVISION.Heterozygote: An individual having different alleles at one or more loci regarding a specific character.Gene Rearrangement: The ordered rearrangement of gene regions by DNA recombination such as that which occurs normally during development.Enzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.Silymarin: A mixture of flavonoids extracted from seeds of the MILK THISTLE, Silybum marianum. It consists primarily of silybin and its isomers, silicristin and silidianin. Silymarin displays antioxidant and membrane stabilizing activity. It protects various tissues and organs against chemical injury, and shows potential as an antihepatoxic agent.DNA, Neoplasm: DNA present in neoplastic tissue.G1 Phase: The period of the CELL CYCLE preceding DNA REPLICATION in S PHASE. Subphases of G1 include "competence" (to respond to growth factors), G1a (entry into G1), G1b (progression), and G1c (assembly). Progression through the G1 subphases is effected by limiting growth factors, nutrients, or inhibitors.Skin Abnormalities: Congenital structural abnormalities of the skin.Chromosome Breakage: A type of chromosomal aberration involving DNA BREAKS. Chromosome breakage can result in CHROMOSOMAL TRANSLOCATION; CHROMOSOME INVERSION; or SEQUENCE DELETION.Grewia: A plant genus of the family TILIACEAE. Members contain lupeol and betulin TRITERPENES.Homozygote: An individual in which both alleles at a given locus are identical.Enzyme Activation: Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.Cytoprotection: The process by which chemical compounds provide protection to cells against harmful agents.Brain Diseases: Pathologic conditions affecting the BRAIN, which is composed of the intracranial components of the CENTRAL NERVOUS SYSTEM. This includes (but is not limited to) the CEREBRAL CORTEX; intracranial white matter; BASAL GANGLIA; THALAMUS; HYPOTHALAMUS; BRAIN STEM; and CEREBELLUM.Cell Transformation, Neoplastic: Cell changes manifested by escape from control mechanisms, increased growth potential, alterations in the cell surface, karyotypic abnormalities, morphological and biochemical deviations from the norm, and other attributes conferring the ability to invade, metastasize, and kill.Nasopharyngeal Neoplasms: Tumors or cancer of the NASOPHARYNX.Cyclin B1: A cyclin B subtype that colocalizes with MICROTUBULES during INTERPHASE and is transported into the CELL NUCLEUS at the end of the G2 PHASE.Sunburn: An injury to the skin causing erythema, tenderness, and sometimes blistering and resulting from excessive exposure to the sun. The reaction is produced by the ultraviolet radiation in sunlight.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Thorax: The upper part of the trunk between the NECK and the ABDOMEN. It contains the chief organs of the circulatory and respiratory systems. (From Stedman, 25th ed)Urogenital Abnormalities: Congenital structural abnormalities of the UROGENITAL SYSTEM in either the male or the female.Chromosome Deletion: Actual loss of portion of a chromosome.Cell Aging: The decrease in the cell's ability to proliferate with the passing of time. Each cell is programmed for a certain number of cell divisions and at the end of that time proliferation halts. The cell enters a quiescent state after which it experiences CELL DEATH via the process of APOPTOSIS.Carcinoma, Squamous Cell: A carcinoma derived from stratified SQUAMOUS EPITHELIAL CELLS. It may also occur in sites where glandular or columnar epithelium is normally present. (From Stedman, 25th ed)Trisomy: The possession of a third chromosome of any one type in an otherwise diploid cell.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Deinococcus: A genus of gram-positive aerobic cocci found in the soil, that is highly resistant to radiation, especially ionizing radiation (RADIATION, IONIZING). Deinococcus radiodurans is the type species.Quinazolinones: Chemicals with two conjoined aromatic rings incorporating two nitrogen atoms and one of the carbons oxidized with a keto oxygen.Mice, Mutant Strains: Mice bearing mutant genes which are phenotypically expressed in the animals.Rad51 Recombinase: A Rec A recombinase found in eukaryotes. Rad51 is involved in DNA REPAIR of double-strand breaks.Sarcoma: A connective tissue neoplasm formed by proliferation of mesodermal cells; it is usually highly malignant.Triacetoneamine-N-Oxyl: Cyclic N-oxide radical functioning as a spin label and radiation-sensitizing agent.Lung Injury: Damage to any compartment of the lung caused by physical, chemical, or biological agents which characteristically elicit inflammatory reaction. These inflammatory reactions can either be acute and dominated by NEUTROPHILS, or chronic and dominated by LYMPHOCYTES and MACROPHAGES.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.RNA, Small Interfering: Small double-stranded, non-protein coding RNAs (21-31 nucleotides) involved in GENE SILENCING functions, especially RNA INTERFERENCE (RNAi). Endogenously, siRNAs are generated from dsRNAs (RNA, DOUBLE-STRANDED) by the same ribonuclease, Dicer, that generates miRNAs (MICRORNAS). The perfect match of the siRNAs' antisense strand to their target RNAs mediates RNAi by siRNA-guided RNA cleavage. siRNAs fall into different classes including trans-acting siRNA (tasiRNA), repeat-associated RNA (rasiRNA), small-scan RNA (scnRNA), and Piwi protein-interacting RNA (piRNA) and have different specific gene silencing functions.Flow 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.Proto-Oncogene Proteins: Products of proto-oncogenes. Normally they do not have oncogenic or transforming properties, but are involved in the regulation or differentiation of cell growth. They often have protein kinase activity.Intestine, Small: The portion of the GASTROINTESTINAL TRACT between the PYLORUS of the STOMACH and the ILEOCECAL VALVE of the LARGE INTESTINE. It is divisible into three portions: the DUODENUM, the JEJUNUM, and the ILEUM.Musculoskeletal Abnormalities: Congenital structural abnormalities and deformities of the musculoskeletal system.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.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.Pulmonary Fibrosis: A process in which normal lung tissues are progressively replaced by FIBROBLASTS and COLLAGEN causing an irreversible loss of the ability to transfer oxygen into the bloodstream via PULMONARY ALVEOLI. Patients show progressive DYSPNEA finally resulting in death.Infrared Rays: That portion of the electromagnetic spectrum usually sensed as heat. Infrared wavelengths are longer than those of visible light, extending into the microwave frequencies. They are used therapeutically as heat, and also to warm food in restaurants.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.In Situ Nick-End Labeling: An in situ method for detecting areas of DNA which are nicked during APOPTOSIS. Terminal deoxynucleotidyl transferase is used to add labeled dUTP, in a template-independent manner, to the 3 prime OH ends of either single- or double-stranded DNA. The terminal deoxynucleotidyl transferase nick end labeling, or TUNEL, assay labels apoptosis on a single-cell level, making it more sensitive than agarose gel electrophoresis for analysis of DNA FRAGMENTATION.Antigens, Nuclear: Immunologically detectable substances found in the CELL NUCLEUS.Radiotherapy, Intensity-Modulated: CONFORMAL RADIOTHERAPY that combines several intensity-modulated beams to provide improved dose homogeneity and highly conformal dose distributions.Rats, Inbred F344Mice, Inbred BALB CRisk 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.Particle Accelerators: Devices which accelerate electrically charged atomic or subatomic particles, such as electrons, protons or ions, to high velocities so they have high kinetic energy.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.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Chromosomes: In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Colony-Forming Units Assay: A cytologic technique for measuring the functional capacity of stem cells by assaying their activity.Transfection: The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.Coptis: A plant genus of the family RANUNCULACEAE. Members contain BERBERINE and other isoquinoline ALKALOIDS.Herpes Labialis: Herpes simplex, caused by type 1 virus, primarily spread by oral secretions and usually occurring as a concomitant of fever. It may also develop in the absence of fever or prior illness. It commonly involves the facial region, especially the lips and the nares. (Dorland, 27th ed.)