Tox 2

BOS 4201, Toxicology 1 Cou rse Learning Outcomes for Unit II Upon completion of this unit, students should be able to: 6. Evaluate the effects of toxins on target organs of the body. 6.1 Identify the factors that modify toxicity. 6.2 Discuss the beneficial applications of toxins. Course/Unit Learning Outcomes Learning Activity 6.1 Unit Lesson, Unit Reading 6.2 Unit Lesson, Unit Reading Reading Assignment Chapter 3: Toxicity and the Factors That Modify Toxic Responses Chapter 4: Biological Poisons: Plant and Animal Toxins Unit Lesson The first part of this unit lesson discusses the factors that modify toxic responses and biological poisons. The second part discusses biological poisons, including bacterial toxins, mycotoxins, and animal and plant toxins. Toxicity and Toxic Responses There is a large variation in the effects of chemicals on the body. Some exa mples of chemical injury include the scenarios below.  Cells and tissue self -repair and return to normal function.  A repair is incomplete but is sufficient to return to normal function.  There is death of an organ or organism.  Neoplastic growth occur s, resu lting in the death of the organism (Richards & Bourgeois, 2014). The following chart demonstrates the variability in the toxic damage to cells. From the chart , you can see how the tissue will either return to normal, be a complete loss of organ function, or result in cancer. The effects of exposure can also be classified as acute or chronic effects. Acute effects are the immediate effects , evident in days to months. Chronic effects are delayed responses that occur from months to years after exposure. An example is carbon monoxide exposure where the acute effects include asphyxiation through carboxyhemoglobin. The chronic effects of carbon monoxide exposure include heart and brain toxicity. One cannot prevent exposure to all toxic chemicals. The toxicity is determined by the physical and chemical properties, the duration of exposure, the route of exposure , and the health of the individual. The routes of exposure include inh alation, ingestion, and absorption . Inhalation is the most common route of exposure. Ingestion of a substance is usually accidental. Absorption through the skin usually occurs when a substance dissolves in the oils of the skin and passes through the pores (Richards & Bourgeois, 2014). UNIT II STUDY GUIDE Factors That Modify Toxic Responses and Natural Sources of Toxins BOS 4201, Toxicology 2 UNIT x STUDY GUIDE Title Factors that modify toxicity are age, disease, gender, lifestyle, diet , and genetics . For age , the decreased organ functions in elderly persons leave them more susceptible to hepatic and renal toxicants. Examples of lifestyle factors are cigarette smoking, drug use, alcohol abuse, and caffeine consumption. A classic example is cigarette smoking and exp osure to a substance such as asbestos. If one is exposed to asbestos and smokes , his or her risk of developing lung cancer can increase by about 80% . There is growing research as to how genetics affect toxicity.

Toxicogenetics examines the effects of chem ical exposure on gene activity and protein expression. According to Rou quie et al. (2015) , toxicogenomic technologies and computational tools are available to provide mechanistic insight in toxicological mo de of action (MOA) of the adverse effects observed in laboratory animals. The vision described as Tox21 (Toxic ology Testing in the 21st century) aims at predicting in vivo toxicity by using a bottom -up approach that starts with understanding MOA based on in vitro data to ultimately predict adverse effects in humans. This is a fairly new approach to toxicity studies and how chemicals can affect an organism. The individual variations in people make some more susceptible or resilient to exposure to hazardous substances than others . There is a difference in the expression of the detoxification enzymes , which results in different rates of biotransformation. Obviously, there are many factors that can modify the toxic response. Biological Poisons: Plant and Animal Toxins Biological poisons include bacterial toxins, mycotoxins , and animal and plant toxins. Toxins are a poisonous substance produced by living things. The categories of toxins , based on what produces them , include the list below:  bacteria ,  fungi (mycotoxins ),  algae (phycotoxins ),  plants (phycoto xins ), and  animals (zootoxins ). An example of a bacterial toxin is the botulinum toxin produced by the bacteria Clostridium botulinum. The botulinum toxin is the most acutely toxic substance known , and the spores are found in the soil. The bacterium Clost ridium tetani produces the toxin tetanus. This toxin causes the skeletal muscles to contract , and death results from respiratory and heart failure. This bacteria can enter the body through wounds or from piercings and tattoo s. Staphylococcus aureus (Staph infection) is another bacteria that produces an alpha toxin. Staphylococcus aureus is the most common cause of nosocomial infections and is frequently responsible for food poisoning. The symptoms of exposure include nausea, vomiting, stomach cramps , and diarrhea. The graphic depicts toxic damage to cells. (Richards & Bourgeois, 2014 ) BOS 4201, Toxicology 3 UNIT x STUDY GUIDE Title Mycotoxins are produced by fungi, some of which are found everywhere in the environment, both indoors and outdoors. Common indoor fungi include Cladosporium , Aspergillus , and Penicillium . These fungi grow on any damp surface in the building environment. Some fungi are associ ated with a condition known as sick building syndrome . Stachybotrys is known to cause irritation of the mucus membranes, headaches, itchy skin, nausea , and fatigue. Th ere is considerable controversy in this area because of the individual susceptibility to the fungus. Fungal toxins that come from mushrooms cause four main types of responses : gastrointestinal effects , disulfiram -like effects, neurotoxic effects , and cytotoxic effects . The gastrointestinal effects include nausea, vomiting , and abdominal cramps. Some mushrooms produce coprine , which interferes with the metabolism of ethanol . If alcohol is consumed within 3 days of exposure to coprine, the effects includ e nausea, headache, and vomiting. Some mushrooms can have neurotoxic effects , which include hallucinations, fever, coma, blurred vision, and difficulty breathing. Cytotoxic effects of mushrooms are not common but include organ failure, jaundice, and a coma . Animal toxins are probably the best -known toxins. For example, scorpions produce a toxin that is neurotoxic but relatively harmless to humans. Another example is venomous snakes . There are many different categories of snakes and the venom they produce. The snake venom contain s enzymes that produce the toxic effects. Acetylcholinesterase is an example of a venom that causes paralysis. An example of a plant that produces a toxin is poison ivy . It produces an organic oil called urushiol that causes an allergic reaction on the skin upon contact. Another example is the giant hogweed. This plant has a clear , watery sap that is a photosensitizer. A photosensitizer sensitizes the skin to ultraviolet light. Exposure to the sap and sunlight can cause swelling, burns, and blisters. Other examples of plants that are dangerous when consumed are listed below:  oleander (contains cardio -glycosides ),  lilies ,  privet (produces berries that contain syringin and ligustrin ),  wolfsbane (contains aconitum in the s eeds and roots ), and  mayapple (contains podophyllotoxin ) (Richards & Bourgeois, 2014) . Some examples of outdoor workers who may be exposed to hazardous plants while performing their jobs are listed below:  construction workers,  road crews,  forestry worke rs,  loggers,  farmers, and  land surveyors. Nerium oleander is an evergreen shrub or small tree in the dogbane family Apocynaceae. It is most commonly known as oleander but has many other names. Oleander is one of the most poisonous of commonly grown garden plants and can be very toxic if ingested in sufficient quantity. (Enking, 2010) BOS 4201, Toxicology 4 UNIT x STUDY GUIDE Title Some coral s also have toxic chemicals, the most deadly being Palythoa . It can kill a human with only four micrograms of toxin . Palytoxin is one of the most toxic organic poisons and includes symptoms of chest pains, breathing difficulties , and a racing pulse. Death can occur within minutes , and there is currently no treatment. An example of an animal toxin is spider venom. The venom of the widow spider is neurotoxic , and exposure results in pain in the lymph nodes, nausea, muscle cramps, profuse sweating, respiratory distress, and even death. References Centers for Disease Control Prevention. (1998). Public Health Image Library (PHIL) [Photograph ]. Retrieved from https://phil.cdc.gov/phil/details_linked.asp?pid=1110 Enking, E. (2010). Nerium oleande r [Photograph ]. Retrieved from https://www.flickr.com/photos/33037982@N04/4964872248/in/photolist -8yJgxE -anuKGE Richards, I. S. , & Bourgeois, M. M. (2014). Principles and practice of toxicology in public health (2nd ed.). Burlington, MA: Jones & Bartlett Learning . Rouquie, D., Heneweer, M., Botham, J., Ketelslegers, H., Markell, L., Pfister, T., . . . Hennes, C. (2015). Contribution of new technologies to characterization and prediction of adverse effects. Critical Reviews in Toxicology, 45 (2), 172 –183. Retrieved from http://www.tandfonline.com/doi/full/10.3109/10408444.2014.986054?scroll=top&needAccess=true Suggested Reading Click here to access the Chapter 3 PowerPoint presentation. Click here to access a PDF version of the presentation . Click here to access the Chapter 4 PowerPoint presentation. Click here to access a PDF version of the presentation . In order to access the following resource, click the link below: The following article is on biological toxins as related to toxicity . Morales, P. J. (2012). The need to establish the organisation for the prohibition of biological weapons: A proposal for the future. Public Organization Review, 12 (1), 57 –70. Retrieved from https://libraryresources.columbiasouthern.edu/login?auth=CAS&url=https://libraryresources.columbia southern.edu/login?url=http://search.proquest.com.library resources.columbiasouthern.edu/docview/9 20111699?accountid=33337 Learning Activities (Non -Graded) Non -Graded Learning Activities are provided to aid students in their course of study. You do not have to submit them. If you have questions, contact your instructor for further guidance and information. Research two extreme cases of plant or animal toxins from the county or municipal health depart ment websites in your area . Find the exposure, the symptoms, and the treatment for each case. Leaves in threes characterize poison ivy . This plant is common in the eastern United States. (Centers for Disease Control and Prevention, 1998)