Environmental Pathology Past Paper 2022 PDF

Dr. Nor SyafinazYaakob Fakulti Farmasi, UKM [email protected]  Climate change  Chemical agents  Physical agents  Environmental pollution  Animal and plant toxins  Bacteria and viruses  Greenhouse effects  Increase in atmospheric level of greenhouse gases (CO2, ozone...

Dr. Nor SyafinazYaakob Fakulti Farmasi, UKM [email protected]  Climate change  Chemical agents  Physical agents  Environmental pollution  Animal and plant toxins  Bacteria and viruses  Greenhouse effects  Increase in atmospheric level of greenhouse gases (CO2, ozone, methane)  How does greenhouse effect occur? http://www.nuralam.net/wp-content/uploads/2015/08/Green-House-Effect.jpg  Greenhouse effect’s impact on climate change?  Health impacts  Cardiovascular & respiratory diseases  Gastroenteritis, water/food-borne diseases  Vector-borne infectious diseases  Malnutrition  Air pollutants  Metals  Lead, mercury, arsenic  Industrial chemicals  Agricultural chemicals  Tobacco smoke  Substance abuse  Alcohol, hallucinogens  Lead (Pb) has been used by humans for at least 7000 years, because it is widespread, easy to extract, and easy to work with. Lead alloys are used in batteries, shields from radiation, water pipes. Lead-containing paint is a primary source of lead exposure in children. Adults absorb 5–15% of ingested lead and usually retain less than 5% of what is absorbed. Children absorb 42% of ingested lead with 32% retention. Lead in blood is primarily (99%) in erythrocytes bound to hemoglobin, only 1% of circulating lead in serum is available for tissue distribution. Inhibition of Ferrochelatase Inhibition of ALAD Klaassen, C.D. 2008. Casarett & Doull’s Toxicology: The Basic Science of Poisons. Ed. ke-7. New York: McGraw-Hill.  Organometallic, CH3Hg+  Major route of exposure : consumption of fish  Cooking does not lower methylmercury content  Well-absorbed from GIT  95% absorbed from fish ingestion  10% distributed to brain, 5% remains in blood  Neurotoxicity (manifestations : paresthesia, ataxia)  Inorganic mercurous (Hg1+) or mercuric (Hg2+) salts  Binds to other elements chlorine, sulfur, oxygen  Can come from _________________  Poorly absorbed from GIT, do not readily pass BBB, excreted in urine and faeces  How is it toxic?  Solvents : a class of organic liquid chemicals ; variable lipophilicity and volatility  Volatile organic compounds (VOC) : organic chemicals that easily evaporate at room temperature i.e. vapors  Organic solvents: dissolve, dilute and disperse materials that are insoluble in water.  Examples of organic solvents:  Dichloromethane used in industrial process, food prep, degreasing agent, aerosol propellent and agriculture (occupationally/ at home)  Carbon tetrachloride used in cleaning agent, fire extinguisher, human antihelminthic  Benzene, can be found in petrols  Passive tobacco smoke inhalation from environment  secondhand smoke  Can cause lung cancer even in nonsmokers, SIDS in babies  Mechanical trauma – is caused by mechanical forces eg. collision, scraping of skin, tear/disruptive stretching of tissues  Abrasion  Contusion/bruise (blunt trauma)  Wounds (internal and external)  Fractures  Caused by excess heat or excess cold  Burns – primary cause; hot liquids  skin damage; complication includes wound infection, to death  Hyperthermia  Exposure to elevated temperature (often at prolonged time) can lead to:  Heat cramps  Heat exhaustion  Heat stroke  Hypothermia  Prolonged exposure to low ambient temperature  Injuries caused by chilling/freezing of cells and tissues  Radiation : ENERGY in the form of particles and waves  Radioactive material : material that is unstable and emits radiation  Ionizing radiations  A radiation which loses energy by producing ion pairs  Enough energy to remove electrons from an atom (matter)  Atom becomes ionized or charged  Different ionization densities  Non-ionizing radiations  A radiation without enough energy to separate molecules or electrons from atoms  www.nuclear-power.net  Ionising radiations : e.g. alpha, beta, gamma rays, x-rays, higher ultraviolet cosmic rays  Non-ionising radiations : e.g. lower ultraviolet, visible light, infrared, microwaves, radio & TV waves, power transmission  Further ref: http://www.who.int/ionizing_radiation/about/what_is_ir/en/index1.html  Direct ionization  Direct energy deposits in DNA – ionization  Produce ion radicals – further react to produce DNA radicals  Indirect ionization  Ionization of other molecules closely associated with DNA e.g. hydrogen, oxygen  Form free radicals – attack DNA  DNA damage  Disruption of chemical bonding in DNA The most radio-sensitive cells are those which:  have a high division rate  have a high metabolic rate  are of a non-specialized type  are well nourished  Spiders  Snakes  Centipedes  Milipedes  Latrodectus species (Widow spiders) venoms  High-molecular weight proteins precusors (about 1000 amino acids)  Only toxic to vertebrates, not to insects or crustaceans  3D structure : tetrameric complexes with a central channel, inserts into lipid bilayer  High affinity binding to Latrophilin (GPCR), and Neurenin (TM receptor)  Affect CNS depolarizing neurons  Increase intracellular [Ca2+]  Stimulate exocytosis of neurotransmitters from nerve terminals  Complex mixtures venome : proteins and peptides, enzymes and non-enzymatic components, inorganic cations  Class of actions :  Neurotoxins – produce neuromuscular paralysis  Coagulants – initial procoagulant action that uses up clotting factors  bleeding, inhibit normal clotting, inhibit platelet aggregation  Myotoxins – direct impact on muscle contraction  paralysis  Cytotoxic – proteolytic or necrotic properties  breakdown of tissues  Nephrotoxins – kidney damage, bleeding General toxicity of plants  Unintentional exposure on contact  Eg. plant pollen  hay fever  Accidental ingestion  Eg. biting leaves (children)  Intentional ingestion  Eg. Herbal supplements consumption (chronic)  Drug – herbal interactions  Eg. Eucalyptus increase hepatic enzymes, increase drug metabolisms  Protein Synthesis Inhibition  Lectins in castor bean : ricin I and ricin II (more toxic)  Ricin II : ▪ A-chain inactivates ribosomal RNA thus blocking protein synthesis ▪ B-chain is linked to A-chain via disulfide bonds ▪ Following ingestion of mottled seeds, usually no marked symptoms within initial several days  gradual loss of appetite, nausea, vomiting, diarrhea ▪ Death possible with high doses  Fungi – Mushroom Poisoning  Most dangerous mushrooms are the Amanita phalloides or the Amanita ocreata. Most susceptible are children less than 10 years  of age Initial symptoms are nausea, vomiting, diarrhea  and irregular heart rate Amatoxin, damages the liver cells causing liver  and kidney failure and possibly death Amatoxin is very potent:  only 0.1 to 0.3 mg/kg of body weight results in death  Toxins produced by Aspergillus flavus and Aspergillus parasiticus  Grow on grains eg. maize, peanuts  Can cause toxic effects on liver; strongly associated with liver cancer