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NE 490 Stuff

Stuff that wasn't on Exam 1 and 2

What is the definition of cancer? Categorized by uncontrollable growth and spread of abnormal cells
What are the different types of cancer? Carcinomas: cells that cover internal and external body surfaces Ex: lung, breast, bladder, colon, prostate Leukemia: cancer of blood cells ex: Stem cells Lymphoma: cells in lymph nodes and tissues Sarcoma: cancer in supportive tissue ex: bones
Difference between benign and malignant tumors Benign don't spread, but can crowd out healthy tumors Malignant will spread
What are germ cells? Reproductive cells- sperm and ovary
What are the different types of effects from radiation? Deterministic: has threshold, above threshold: increase severity Stochastic: no threshold, probability increases with dose
What types of cancers were popular with x-ray workers? skin cancers and leukeima
What types of cancers were popular with Saxony pitchblade miners and uranium miners? Lung cancers
What workers had bone cancers? Radium: the dial painters and the people treated with radium salt (ankylosing spondylitis & tuberculosis)
What cancer did people who were treated with Thorotrast have? Liver
What is a latent period? Time period between irradiation and appearance of disease Leukemia 5 –15 years (shortest) Solid cancers possibly 10 -60+ year
What are the different risk models? Absolute, relative
Describe absolute risk model the chance of a person developing a specific disease over a specified time-period radiation induces cancers at some fixed number above the natural incidence
Describe relative risk model compare risk in two different groups of people radiation increases the natural incidence at all ages proportional to spontaneous background rates (predicts a larger number of induced cancers in old age)
Describe time-dependent relative risk model function of dose, age at exposure, time since exposure, gender, etc. (Favored by BEIR)
How do you calculate relative risk? p(event when exposed)/p(event when non-exposed)
What is dose rate effectiveness factor? the dose rate effectiveness factor by which cancer risks are reduced for low dose rate, 2-10 for animals, around 1.5-2 for humans
How is dose affected by cataracts? The higher the dose, the less of a latent period before cataract development
How is high LET radiation affected by cataracts? At high doses, RBE = 10 for neutrons At low doses, RBE = 50 for neutrons
Where do radiation induced cataracts typically develop? in the posterior region
What is the typical latent period for cataracts based on dosage? 2.5 –6.5 Gy -~8y 6.5 –11.5Gy -~4y
What is the threshold dose for cataracts? ~2 Gy for threshold ~5-8 Gy for prolonged/fractionated exposure
What are the germ cell radiation effects for males? It may take several weeks for rad symptoms to fully exposed, threshold for temp sterility is ~0.15 Gy, perm is ~6 Gy, no physical changes
Describe the germ cell for males. Sperm, goes through several divisions before progress to spermatozoa (~10 weeks)
What are the germ cell radiations effects for females? No gamete stem cells after birth, produced hormonal changes, similar to menopause, ~4 Gy is perm sterility
What is the difference between heterozygous and homozygous gene pairs? 2 genes in pair are alike in homo, 2 genes in pair are unalike in hetero
What does the y chromosome do? Determines sex
What is doubling dose? dose of radiation, if given uniformly to an entire population, needed to double the spontaneous mutation rate
What are the different mutation types? Mutation, somatic mutations, germline mutations
Describe mutation. Any change in chromosome, genes, and DNA
Somatic mutation not inheritable, occurs when the DNA of a non-reproductive cell is damaged radiation-induced somatic mutations affect only the exposed individual
Germline mutation inheritable, occurs when the DNA of a reproductive cell (sperm or ovum) is damaged example effects include miscarriages, stillbirths, congenital defects, premature death (first year of life), chromosomal abnormalities, and cancers
What is the definition for single gene mutations? DNA structural change Recessive mutations-require that the gene be present in duplicate to produce the trait (unless X-linked) Dominant mutations-require only one gene to produce the trait
What are the two heredity changes that are possible for radiation damage? Gene mutations: dominant, recessive, sex-linked Chromosomal changes: too many or too few. chromosome aberrations Multifactorial
What were the conclusions from the megamouse study? Radiosensitivity of different mutations varied significantly,only possible to speak in terms of average mutation rates, A substantial dose-rate effect in mice was observed, spreading out dose resulted in fewer observed mutations.
Other conclusions from megamouse study? Male mice were more radiosensitive than female mice at low dose rates, almost all genetic burden is carried by males, Genetic consequences of a given dose were greatly reduced if time was allowed between irradiation and conception
Is there a signature lesion or mutation from ionizing radiation? No, Radiation tends to affect the same mutations that are induced spontaneously
Is the number of mutations proportional to dose of radiation? Yes
What are the developmental effects of radiation of an unknown child? Lethal effects Malformations Growth disturbances
What is preimplantation? up to 5th day in mice, 10th day in humans, most sensitive stage to LETHAL effects, 0.1 Gy and above is lethal, "all or nothing" effect
What is organogenesis? Period where all of the major organs are being developed, end of preimplantation an lasts until beginning of fetal period, irradiation results in structural, congenital anomalies, greatest temp growth retardation
What is the fetal period? 14th day onward in mice; or at about 6 weeks onward in humans, largest degree of perm retardation, Effects on kidneys, hemotapoietic system, liver, gonads
The dose response curve for radiation-induced mutations was linear with no threshold: T or F? True
What does repair do? spares late responding normal tissue preferentially, repair of sublethal damage
What does reassortment/redistribution of cells in the cell cycle? increases acute effects, no influence on late effects, increases damage to tumor
What does Repopulation/Regeneration do? spares acute responding normal tissue preferentially, no influence on late effects, danger of tumor repopulation
What does Reoxygenation do? no influence on normal tissue responses, increases tumor damage
Created by: 1672073429469679