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RAD Protect:
Molecular Cellular Biology
| Question | Answer |
|---|---|
| The Law of Bergonie & Tribondeau is related to the: | Radiosensitivity is a function of the metabolic state of tissue being irradiated - Tissue with HIGHER metabolic rate are more sensitive |
| Bergonie & Tribondeau found that radiation is more effective against: | - cells that actively dividing - undifferentiated cells - cell with a long dividing future |
| Who modified Bergonie & Tribondeau's theory? | Ancel & Vitemberger |
| They modified the Bergonie & Tribondeau's theory to say that: | Inherent susceptibility of any cell to damage by ionizing radiation is the same, BUT, that the time of appearance of radiation-induced damage differs among different types of cells. |
| The appearance of radiation damage is influenced by: | - biologic stress on a cell - conditions to which cell is exposed pre and post irradiation |
| What are the three external factors that affect radio sensitivity / Cell and Tissue responses? | - physical - chemical - biological |
| How does LET affect the severity of radiation response | LET (energy absorb by body) - irradiation of same biological system with different LET radiation will produce different severity of response HIGH LET = more damage = ALPHA RADIATION |
| RBE compares the response to: | RBE (damage by LET) compares response to quality of radiation HIGH LET = HIGH RBE |
| RBE increases as dose per fraction: | RBE increases as dose per fraction increases, BUT, RBE & dose per fraction is DEPENDENT on size & shape of initial portion of survival curve |
| What is the dose rate? | rate at which radiation is delivered |
| How does dose rate affect radiation response? | low dose rates produce LESS damage than high dose rates |
| What are radiation sensitizers? | chemicals that enhance responses to radiation |
| What is the response of cells to radiation in the presence of oxygen? | Oxygen Effect |
| What is OER? | Oxygen Enhancement Ratio HIGH LET means OER is not very effect LOW LET means OER is more effect |
| What is the OER formula? | dose w/out Oxygen OER = _______________________ dose w/ oxygen |
| What chemical mimics oxygen & its effect? | Nitro-imidazoles |
| What are radiation protectors? Give example | reduces effects of radiation..... example is SULFHYDRYL |
| What biological factors affect radiosensitivity? | - position if cell in cycle at time of irradiation - IntraCellular Repair - capability of cell to repair sub-letah damage - If dose delivered in fractions, over time, the # of cells surviving increases w/ time b/w fraction - Fractionization - |
| List cell/tissue sensitivity from highest radiosensitivity to lowest. | LymphoCytes Spermatogonia LeukoCytes ErythroCytes Intestinal Crypt Cells EndoThelial Cells OsteoBlasts Spermatids FibroBlasts Muscle Nerve Chondrytes / Cartilage |
| What is used to compare & contrast responses to different tissues to radiation? | ASSAY |
| What are the criteria for assay of tissue? | - must be Quantifiable - effect must INCREASE with INCREASE in dose |
| Assays of damage in organized tissues & organs can be divided into: | - Clonogenic = reproductive stem cell - Specific Tissue Function - Lethiality |
| What is the LD 50/30? | Lethal Dose that kills 50% of pop. in 30 Days ( LD 50/30 ) |
| Define dose response relationship. | a graph of radiation dose and magnitude of observed response |
| What is a linear relationship? | response directly related to dose |
| What is a non linear relationship? | response is NOT directly related to dose |
| What is a nonthreshold relationship? | ANY dose regardless of its size is EXPECTED to produce a response |
| What is a threshold relationship? | has a dose at which NO response would be expected |
| Early EFFECTS of RAD - Response of an organism to total body radiation is determined by: | a combined response to of all systems in the body |
| Total body radiation syndrome occurs under the following conditions: | - acute exposure - total body exposure - external radiation |
| When do early effects of radiation occur? | within days / weeks of exposure |
| What is the acute radiation syndrome? | syndrome following exposure - leading to death (more than 100rads) |
| What are the 3 stages of acute radiation syndrome? | - Prodromal - Latent - Manifest |
| What are the symptoms of prodromal stage? It occurs at dose above: | Symptoms: Nausea, Vomit, Diarrhea, decrease white blood cell (leukopenia) Occurs at Dose above 100 rads Appears within mins/hrs and lasts up to 2 wks |
| What is the latent stage? | Healthy Appearance - Chgs are taking place in systems damaged by radiation - will lead to either demise or recovery of individual Can last weeks to months |
| What is the manifest stage? | Symptoms reflect damage to systems.... person either recovers or dies |
| Where has data been accumulated to study early effects of radiation? | - lab & industry accidents - Pacific test grounds - Hiroshima & Nagasaki - Cancer Therapy - Chernobyl Accident - Fukushima Accident |
| Acute radiation syndrome is classified into what 3 syndromes? | 1- Bone Marrow (hematologic) 2- GastroIntestinal 3- Central Nervous System (CNS) |
| What dose can cause the hematologic syndrome? | Dose of 100 to 1000 Rads |
| During the bone marrow syndrome, what happens in the prodromal stage, latent stage & manifest stage? | PRODROMAL - few hrs after exposure -Symptoms are Nausea, Vomit, & Diarrhea LATENT - few days to 3 wks post exposure. Number of blood cells in circulating blood not severely depressed , so person seems well, BUT stem cells in bone marrow are dying MANIFEST - 3to5 wks post exposure - Pancytopenia occurs - Symptoms are Vomit, Diarrhea, malaise, lethargy, Fever - Death occurs due to infection, hemorrhage, electrolyte imbalance & dehydration |
| The mean survival time for bone marrow syndrome is: | 18 to 24 months |
| The GI syndrome occurs at what dose? | dose of 1000 to 5000 Rads |
| Survival time ______________ with the dose. ____________ occurs at same time regardless of the ________________. | Survival time _DOES NOT VARY_ with the dose. _DEATH_ occurs at same time regardless of the _DOSE_. Appears 3 to 10 days post exposure with no medical attention |
| During the GI syndrome, what happens in the prodromal stage, latent stage & manifest stage? | PRODROMAL - occurs w/in few hrs post exposure. Symptoms are Nausea, Vomit, Cramps, diarrhea. This stage last 1 day. LATENT - 2 to 5 days post exposure - Person feels OK MANIFEST - 5 to 10 days - Symptoms are severe Diarrhea, Nausea, Vomit, Fever |
| Damage by radiation in the GI syndrome is primarily in the________________________ | small intestine, but also bone marrow |
| Radiation can cause destruction of the Cells in the ______________________________.The ___________ will not be able to: | crypts of Lieberkuhn. the Villi will be able to absorb materials across the intestine wall |
| In the GI syndrome, _____________________ is absorbed by the bloodstream causing: | Bacteria - causing infection & death |
| Death due to the GI syndrome is due to: | |
| What are the symptoms of the GI syndrome? | Anorexia, Diarrhea, Fever, Dehydration |
| The Central Nervous System syndrome occurs at does greater than: | greater than 5000 rads |
| In the CNS syndrome, what occurs in the prodromal stage, latent stage, & manifest stage? | PRODROMAL - appears few mins/ hrs depending on dose. Symptoms are extreme Nervousness, Confusion, severe Nausea, & Vomit - loss of consciousness & burn sensation to skin LATENT - lats several hrs MANIFEST - appears 5 to 6 hrs post exposure .... DEATH Symptoms are Disorientation, loss of Muscle Coordination, Watery Diarrhea, Seizures, Coma, Dyspenia, loss of Equilibrium, Lethargy, DEATH |
| In the CNS syndrome, death is suggested to be due to: | due to increase press in the cranium caused by damage to blood vessels (edema) |
| The mean survival time for CNS syndrome is: | Avg survival time b/w exposure and death |
| What is the LD 50/30 & LD 50/60? Which is more relevant for humans? | Lethal Dose to 50% of pop in 30 days Lethal Dose to 50% of pop in 60 days LD 50/60 is more relevant to humans |
| In local tissue damage response depends on: | depends on Radiosensitivity, Cell Proliferation, and Maturity of Cell |
| The skin is composed of the : | Epidermis, Dermis, SubCutaneous, FAT, and Connective Tissue |
| At 200-300 KV skin damage may include: | Erythema - redness to skin Desquamation - ulceration of skin Epilation (alopecia) - loss of hair |
| What is erythema? | Erythema - redness to skin |
| What is Desquamation? | Desquamation - ulceration of skin |
| What is Epilation? | Epilation (alopecia) - loss of hair |
| Skin reaction to radiation follows what dose response relationship? | follow Non-Linear Threshold relationship - requires dose threshold before damage |
| What is the skin erythema dose? | SED - 500/600 rad will affect 50% of subjects |
| The gonads are very: | very Radiosensitive |
| In the female radiation effects are _____________ dependent. | AGE DEPENDENT |
| In females, ___________rads can cause temporary sterility , ___________rads can cause permanent sterility. | 200 Rads - Temp Sterility 500 Rad - Perm Sterility |
| What is the germ cell in the male? What effect occurs at high doses? _____________ is discouraged following high radiation dosage. | Male Germ Cell = Spermatozoa ATROPHY (wasting) occurs at HIGH DOSES PROCREATION is discourage following HIGH DOSES |
| In males, ____________rads can cause temporary sterility, ____________rads can cause permanent sterility. | 200 Rads - Temp Sterility 500 Rads - Permanent Sterility |
| The hemopoietic system includes: | Hemopoietic (Blood) system includes: Bone Marrow, Blood, Lymphoid Tissue |
| Radiation will __________ the number of blood cells manufactured in _______________ | Radiation will DECREASE # of red blood cells made in bone marrow |
| What are the types of blood cells? | Lymphocytes - immune system Granulocytes - fight bacteria Thrombocytes (platelets) - initiate clotting Erythrocytes - transport oxygen |
| List blood cells from most radiosensitive to least radiosensitive. | Lymphocytes - immune system Granulocytes - fight bacteria Thrombocytes (platelets) - initiate clotting Erythrocytes - transport oxygen |
| What is cytogentics? | study of cell genetics - ANY radiation causing disturbance of cell function & division; may cause ANY type of Chromosome Abberation (mutation) |
| Cytogentics - These effects have what dose response relationship? | Linear NonThreshold dose response |
| Radiation damage to cells appears at the next ___________following irradiation. It may take ___________________________ before any effects are seen. | mitosis may take MONTHS or YRS before any effects are seen |
| Chromosome damage may be caused by: | Single or Multi hits Multi Hit aberration is the most significant in LATENT human damage |
| Which cause of Chromosome damage is most significant in latent human damage? | Multi Hit aberration is the most significant in LATENT human damag |
| Which of the following are parts of the law of Bergonie & Tribondeau? a. A fetus is less radiosensitive than an adult b. Stem cells are radiosensitive c. The more mature a cell, the more radiosensitive it is d. When proliferation rate is high, so is radioresistance | b. Stem cells are radiosensitive |
| The Law of Bergonie & Tribondeau states that a. Mature cells are more sensitive than stem cells b. Metabolic activity results in radioprotection c. Radiosensitivity increases with increasing hypoxia d. Radiosensitivity increases with proliferation rate | d. Radiosensitivity increases with proliferation rate |
| The RBE a. Describes tissue radiosensitivity b. Increases as x-ray energy increases c. is a descriptor of type of radiation d. is equal to 3 keV/um for alpha | b. Increases as x-ray energy increases |
| The law of Bergonie & Tribondeau relates to which of the following? a. Radiocurability & tumor size b. radioresistance & cell lethality c. Radioresistance & oxygenation d. Radiosensitivity & cellular differentiaiton | d. Radiosensitivity & cellular differentiaiton |
| What is Fractionation? | break up dose into smaller amounts over time |
Created by:
jeffmcmullen