Adobe Systems Aim of the practicals ̶Basic of radiobiology ̶Model of acute radiation syndrome - blood form ̶Evaluation of the data obtained during practice on a model of acute radiation syndrome Adobe Systems Ionizing radiation ̶The radiation emitted by radioactive nuclides ̶Electromagnetic or corpuscular radiation, which causes the penetration of mass ionization (must have sufficiently high energy). ̶Energy is in the range of keV-MeV Types of ionizing radiation Corpuscular α, β, neutrons electromagnetic γ RadiationPenetration2-pn ral2-3 Adobe Systems The energy spectrum of radiation Výsledek obrázku pro radiation energy vs ionisation vs damage Adobe Systems Ionization vs. excitation M M+ + e- M Mexcit •Ionization = process of creating charged atoms •Excitation = atoms absorp energy without ionizazion. Orbital electrons are raised to next level. • • Both types of interactions are very fast • • Formed in a ratio of 1:2 • Výsledek obrázku pro radiation energy vs ionisation vs excitation Adobe Systems ̶MeV, a unit of energy ̶Roentgen, a unit of exposure [C / kg dry air] ̶Becquerel, activity [s-1] ≈ Curie ̶Gray, dose [J / kg] ≈ rad ̶Sievert, dose equivalent [J / kg] ≈ rem Units Adobe Systems https://upload.wikimedia.org/wikipedia/commons/0/03/SI_Radiation_dose_units.png ̶Dose equivalent ̶ = dose * constant WR ̶γ, β, X = 1 ̶neutrons = 10 ̶α = 20 Units Sources of ionizing radiation? Natural space exposure increases with altitude solar terrestrial sources natural radioactive decay of radioisotopes (soil and rock) Radon gas, there is a decay of radium-226 (Uranium) Artificial medicine diagnosis, therapy, sterilization industrial nuclear energy radsources raddoses Adobe Systems Biological effects of ionizing radiation ̶Direct ionizing = direct destruction of biomacromolecules ̶Indirectly (nondirect) effects = production of free radicals (radiolysis of water) ̶ Výsledek obrázku pro cells ionisation effect Chemical effect of ionizing radiation Oxygen effect!! Radiolysis_of_water Výsledek obrázku pro gamma radiation protein damage Adobe Systems Výsledek obrázku pro cells ionisation effect Výsledek obrázku pro cells ionisation effect DNA damage Very serious state DNA damage is reflected in the synthesis of damaged proteins DNA repair mechanisms Reproductive ability of cells Image:Brokechromo.jpg Výsledek obrázku pro heterochromatin dividing vs non dividing Výsledek obrázku pro heterochromatin dividing vs non dividing Výsledek obrázku pro heterochromatin dividing vs non dividing Adobe Systems Mechanisms of DNA damage 5174 https://www.bio-connect.nl/uploads/websiteimages/1%20Lev%20BC/GeneTex/DNA-repairs.gif damage response enables life on earth as we know it Adobe Systems Výsledek obrázku pro proteins radiation figure Improving the Therapeutic Ratio of Radiotherapy by Targeting the DNA Damage Response | Radiology Key Adobe Systems Výsledek obrázku pro parp inhibitors Repair mechanisms Direct repair Excision repair Mismatch repair SSB repair (DSB repair) Image:Dnarepair1.jpg Adobe Systems Effects of ionizing radiation on the human body ̶Deterministic effects ̶Stochastic effects Adobe Systems Deterministic effects ̶There are those that will take effect after total body irradiation, or a tissue once ̶The dependence of the probability of occurrence of damage to an equivalent dose have the sigmoid character Adobe Systems Deterministic effects ̶Acute radiation sickness (radiation syndrome) ̶Local acute skin damage ̶Damage to fetus ̶Infertility ̶Lenticular opacities Adobe Systems Stochastic effects ̶They result from damage to a small number of cells ̶They can occur after a single exposure of sub-threshold dose or chronic radiation tissue or whole body Character of biological effects Deterministic – severity dependent (“determined”) on the dose – manifestation is specific – effect only when exposure exceeded threshold – damage of large amount of cells – onset rather close to the exposure (short latency) – types: acute radiation syndrome chronic post-radiation syndrome cataract, radiation dermatitis, damage of the foetus in utero sterility Stochastic – probability increases with the dose (not the severity!) – manifestation non-specific – gradual increase of the risk without “safe” threshold – damage of the single cell enough to cause effect – manifestation delayed (typically years) – types: somatic mutation - cancer leukemias, thyroid, lung, breast, bones germinative mutation (oocyte, sperm cell) Acute radiation syndrome affecting the hematopoietic, gastrointestinal system and cerebrovascular timing, extent and severity graded according to the dose - deterministic effect!! from several hours to several months after exposure acute radiation syndrome Adobe Systems Acute radiation syndrome ̶Haematopoetic syndrome (> 1GY) ̶GI syndrome (> 10Gy) ̶early (hours) - nausea, vomiting, diarrhea ̶late (days) - loss of intestinal integrity malabsorption, dehydration, toxemia / sepsis, ileus, bleeding ̶Cerebrovascular syndrome (tens of Gy) ̶headache, cognitive impairment, disorientation, ataxia, convulsions, fatigue and hypotension ̶Cutaneous ̶erythema, burns, edema, impaired wound healing Hematopoetic syndrome bone marrow irradiation (> 1GY) leads to an exponential cell death - haematological crisis marrow hypoplasia to aplasia + peripheral pancytopenia (infection, bleeding) subpopulation of stem bb is selectively more radioresistant, (probably due to predominance bb. stage in Go) necessary for regeneration anemia is the result of late (erythrocytes ~ 120 days)! massive stress response (glucocorticoids) contribute to lymphopenia (cytolytic effect) and paradoxically delay the onset of granulocytopenia (release stocks. granulocytes from the spleen) blood count Blood Count Adobe Systems Therapeutic effects of ionizing radiation ̶Teleterapy (60Co) ̶Contact therapy (32P, 90Sr) ̶Brachytherapy (60Co, 137Cs) ̶Endotherapy (Na131I) ̶Radioimunotherapy ̶ hemopoiesis Hemopoesis ex20 • Erythropoiesis erythropoiesis http://www.noblesmedart.com/morph.mov Adobe Systems Erythropoiesis ̶Erythropoiesis is the development of mature red blood cells (erythrocytes). ̶Like all blood cells, erythroid cells begin as pluripotential stem cells. ̶The first cell that is recognizable as specifically leading down the red cell pathway is the proerythroblast . ̶As development progresses, the nucleus becomes somewhat smaller and the cytoplasm becomes more basophilic, due to the presence of ribosomes. In this stage the cell is called a basophilic erythroblast . ̶The cell will continue to become smaller throughout development. As the cell begins to produce hemoglobin, the cytoplasm attracts both basic and eosin stains, and is called a polychromatophilic erythroblast . ̶The cytoplasm eventually becomes more eosinophilic, and the cell is called an orthochromatic erythroblast . ̶This orthochromatic erythroblast will then extrude its nucleus and enter the circulation as a b . Reticulocytes are so named because these cells contain reticular networks of polyribosomes. As reticulocytes loose their polyribosomes they become mature red blood cells. Adobe Systems Reticulocyte 001 Adobe Systems Reticulocytes ̶Reticulocytes are immature red blood cells, typically composing about 1% of the red cells in the human body. ̶Reticulocytes develop and mature in the red bone marrow and then circulate for about a day in the blood stream before developing into mature red blood cells. ̶Like mature red blood cells, reticulocytes do not have a cell nucleus. ̶They are called reticulocytes because of a reticular (mesh-like) network of ribosomal RNA that becomes visible under a microscope with certain stains such as new methylene blue. C:\Dokumenty\retik.jpg Adobe Systems Classification of reticulocyte counts ̶Counting with imersion, magnification 100 ̶ ̶Out of 1000 RBC in the moving viewing field, the number of RET will be counted ̶Normal counts RAT: app. 20 %o RET ̶Normal counts MAN: app 0.5-1.5% (5-15%o) RET ̶ number: increasing bloodforming (regeneration) ¯ number: inhibition of erythropoiesis Adobe Systems Differential leucocyte counts ̶Changes in WBC number (%) ̶Indication of infection, poisoning, leukemia, chemotherapy, alergic reaction ̶ ̶Normal WBC counts in man: ̶neutrophils 60-70% (incr. in bacterial infection) ̶lymphocytes 20-25% (incr. in viral infection) ̶monocytes 3-8 % (incr. in fungal/viral infection) ̶eozinophils 2-4 % (incr. in alergic reaction and parasital infect.) ̶bazophils <1% (incr. in alergic reaction) Adobe Systems Normal counts of WBC in rat ̶Number of WBC............cca 12.5 tis.mm-3 - neutrophil granulocytes 18 - 36% - eozinophil granulocytes 1 - 4% - bazophil granulocytes 0 - 1% - lymphocytes 62 - 75% - monocytes 1 - 6% Blood smear neutrophil „band“ neutrophil „segment“ monocyte lymphocyte eozinophil bazophil trombocyte C:\Dana\Dokumenty\Praktika\Radiace_2\HEME100.jpg Adobe Systems Praktikum I - design Schema Praktika_1 Adobe Systems Praktikum I – operační postup Operacni Pristup Adobe Systems Praktikum I - hodnocení Schema Praktika_A Burkerova_komurka 0,2 mm 0,05 mm Výška = 0,1 mm Adobe Systems • The stained smear will first be viewed at a low magnification and an area where white cells are not overlaid by red cells will be selected. • Using an immersion objective, a total of 100 WBC will be registered and identified as to their individual type. • The viewing field will be moved in order to count the prescribed number of leucocytes. • • Viewing of smear Adobe Systems Výsledek obrázku pro that's all folks j.gumulec@med.muni.cz | @jarogumulec | www.med.muni.cz/masariklab