Many of the different professional groups may be involved in dealing with toxic chemicals including chemists, environmental scientists, food scientists, forensic scientists, clinical scientists, and regulators. Depending on their professional roles, they may take different approaches to dealing with toxic chemicals and their effects. 5 Types of Toxicology Specialty Fields Descriptive toxicology Involves toxicity testing of drugs and chemicals. Decides if a substance is toxic and the level of toxicity. Mechanistic toxicology Involves how toxic chemicals cause toxicity effects at the biochemical and system level e.g. neurochemical site blockage Regulatory toxicology Assessment of therapeutic and consumer chemicals by regulatory bodies. Various federal government agencies set standards for use, transport, and storage. Clinical toxicology Clinical Toxicologists ask the question, what was the victim poisoned with? Their conduct is in support of medi...
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Objectives Appreciate that all substances are potentially toxic Have a basic understanding of the scope of toxicology Appreciate that many scientists, technicians, clinicians, and regulators are concerned with toxic chemicals Understand there are different fields and applications of toxicology and different aims and approaches when dealing with toxic chemicals and effects The scope of toxicology Toxicology is the study of the harmful effects of chemicals on living organisms. Toxicology is a branch of pharmacology, dealing with the origin, nature, chemistry and adverse effects of chemical substances. Toxicology is the study of harmful effects of chemicals on living organisms, including the origin, nature, chemistry & adverse effects of chemical substances Potentially toxic substances include: Food Drinking water Air Medications Cosmetics Bites and Stings Venomous animals and plants Today, much knowledge of toxic substances comes from la...
Assignment title: Is it Bird Flu or Human Flu Subject: Medical Microbiology and Immunology Mark: 8/10 lost two points for needing more specific information and missing the websites on the reference list. Criteria Identify the pathogen(s) involved. Outline the type of immune defenses that might be operating. How does the pathogen enter the body, cause disease and how is it transmitted? What is the outcome of the infection? How is the disease diagnosed? What strategies exist (if any) to control the infection? References Is it Bird Flu or Human Flu? The Enemy - Microbes Avian Influenza A, also known as H5N1 or Bird Flu, is an enzootic member of the orthomyxoviridae family, representing an enveloped, ssRNA viral molecule, with surface hemagglutinin and neuraminidase surface glycoproteins. (1) The Defence - Host Disease H5N1 is more prevalent in birds in China, Asia, Europe and Africa, however, mutations have crossed the animal to human barrier causin...
Progressive Types Of Cell Injury & Response Investigating disease includes collating a clinical history, examination, offering a provisional diagnosis and providing a confirmation of diagnosis via diagnostic or lab investigation. Cell injury can be caused by: Physical trauma Extreme temperatures Electrical disturbance Chemical or radiation poisoning Biological agents Nutritional issues Most of the above cause radical production, a decrease in oxygen delivery or an increase in calcium intercellular release. They could be either reversible or irreversible causing necrosis (cell/ tissue injury) or apoptosis (normal physiological process). Hypoxia conditions can include: Stroke Brain trauma Arteriosclerosis Injury leading to hypoxia A decrease in ATP production An increase in sodium and H2O into cells An increase in potassium outside the cell Increased osmotic pressure Vacuoles formed Increased vaculation Incre...
Sequence Of Events for Vascular Cellular Repair and the Inflammation Response A break in the skin occurs Bacterial reproduction increases Macrophages engulf bacteria Macrophages secrete cytokines Activated mast cells secrete histamine Histamine and cytokines increase dilation of blood vessels White blood cells (WBCs) adhere to capillary lining (pavementing) WBCs migrate to injured site via endothelial cellular gaps via diapedis movement Monocytes turn into macrophages Macrophages and neutrophils engulf pathogens (phagocytosis) Red Blood Cells increase in concentration causing redness and head An increased amount of fluid migrates to the area causing swelling and pain. Tissue repair commences and systemic responses may be evident e.g. fever What is involved in the tissue repair response? Resolution – the toxin is neutralized, oedema decreases, capillary permeability decreases and vasoconstriction occurs Regeneration & replacement – proliferation...
Vascular & Cellular Changes Produced By Chemical Mediators Causing Inflammation Inflammation is a vascularised response to injury, mostly an immune response to infectious organisms, trauma, surgery, chemicals and extreme heat and cold. The suffix "itis" e.g. appendicitis characterises inflammation, therefore appendicitis is inflammation of the appendix. Acute inflammation Symptoms Includes vascular and cellular phases including: Redness due to hyperemia (increased blood flow) Heat due to hyperemia Swelling due to increased capillary permeability and filtration Pain due to inflammatory chemicals (bradykinin) and fluid pressure on nerves or nerve injury. The purpose of inflammation is to decrease the spread of pathogens giving the body an increased chance of removing them and damaged tissue debris and to repair the tissue damage. The sequence of acute inflammation Change in vascular calibre and blood flow Change in vascular blood flow Cellul...
How to Distinguish Between Hyperplasia, Hypertrophy, Necrosis, Atrophy & Apoptosis Topic 1 - Cellular Changes in Disease What is Hyperplasia? An INCREASE in the NUMBER of cells due to an adaptive change e.g. the removal of a kidney What is Hypertrophy? An INCREASE in the SIZE of cells due to an adaptive change e.g. half a heart not functioning What is Atrophy? A DECREASE in the SIZE of cells, failure to adapt to change, loos of cytoskeleton and organelles e.g. muscular dystrophy What is Metaplasia? One adult cell is replaced with a different adult cell What is Dysplasia? An abnormal change in size, shape and organisation (not adaptive) What is Necrosis? Necrosis is cell death caused by injured cells, usually by enzymes or denatured proteins. Types of necrosis include Coagulative, Liquefaction or Casseous Coagulative necrosis - Occurs in the heart, kidney and adrenal glands. Results from ischemia or hyp...
Cellular change in disease are often non-specific or adaptive changes to injury. Cellular disease can be identified if there are: External indicators Physical measurement changes Biochemical changes Changes in the pathology of the cell Cell damage depends on type of agent or stress, type and duration of injury or type of tissue involved. Cellular changes which are all adaptations to stressors include: Hypertrophy Atrophy Hyperplasia Metaplasia Dysplasia Handy Hint! How can you memorize the above? MADHH ( MAD H airy H ead) M etaplasia, A trophy, D ysplasia, H ypertrophy, H yperplasia How does the lack of oxygen affect cells? Hypoxia is the lack of oxygen in cells which is the most common cause of cell injury and most commonly caused Ischemia (reduced blood supply) however can also be caused by any of the following: Decrease of oxygen in the air Loss of haemoglobin or loss of Hb (Haemoglobin) function Decr...