Ch 9 Flashcards
What diseases are caused by greenhouse gases and climate change? 4
- Cardiovascular/Cerebrovascular/Respi - heatwaves and air pollution
- Gastroenteritis - cholera due to water pollution
3.vector borne infections eg malaria increased weather temp
4.Malnutrition - reduced crop production
What is a Xenobiotic?
Exogenous chemicals in environment - air, water, food and soil which can become toxic or non toxic compounds
The most important catalyst of phase I reactions are (group of enzymes)
Cytochrome p450
What does the cytochrome P450 do?
Catalysed reactions that detoxify xenobiotics or convert them to active compounds that cause cell injury
What is smog?
Smoke and fog
What are examples of outdoor air pollutants?
Ozone
Lead
CO
Sulfur dioxide
What is the affinity of CO to Hb?
200x
What happens to CO in the environment?
Becomes oxidised to CO2
How does CO poisoning cause death?
CNS depression –> coma
Where are ischemic changes seen in the brain of CO poisoning?
Basal ganglia
Lenticular nuclei
What is the classic sign of acute CO poisoning in a fair skinned person?
Cherry Red skin and mucous membranes (high levels of carboxy haemoglobin)
What test is used to diagnose CO poisoning?
Blood levels of carboxyhb
The no 1 cause of lung cancer in non smokers is from (pollutant)
Radon
—-(pollutant) can cause legionnaires disease and viral pneumonias
Bioaerosols (from pet dander, dust mites)
Formaldehyde is considered a (term)
Carcinogen
How does lead cause disease?
Binds to sulfhydryl groups on proteins and interferes with calcium metabolism —> skeletal, neurological, GI, renal toxicity
Where is most of lead stores in the body (children)
Children: teeth and bones (80-85%). The rest in blood
The rest in blood (5-10%) and soft tissues
What effects are associated with lead level of 10ug/ml? 4
low IQ, hearing impairments/growth impairments/peripheral nerve function impairment
What effects are associated with lead level of 40 ug/ml? 1
Decreased Hb synthesis
What level of lead is associated with death?
150 ug/ml
What symptoms are associated with lead level of 100ug/ml? 4
Frank anemia
Nephropathy
Encephalopathy
Colic
How does lead interfere with haemoglobin synthesis?
Inhibits Delta aminovulimic dehydratase and ferrochelatase (haem synthesis)
Inhibits Na-K dependant ATPases in membranes (increases fragility of RBCs)
What is diagnostic findings of lead poisoning?
Elevated Lead levels plus either
Elevated RBC free protophyrin levels
Or elevated zinc protophyrin levels
What kind of anemia is seen in lead poisoning?
Microcytic
Anemia and basophilic stippling is classically associated with (disease)
Lead poisoning
Radiodense lead lines: lead poisoning
Radiodense lead lines: lead poisoning
What are the neurological effects of lead poisoning: children vs adults?
Children: Brain damage
Adult: peripheral demyelinating neuropathy
Lead exposure can lead to which renal problems? 2
Interstitial fibrosis
Decreased uric acid excretion eg saturnine gout
What are the types of mercury? 3
- Organic (methyl mercury)
- Inorganic (mercuric chloride)
- Metallic (elemental mercury)
What are the main sources of mercury? 2
Contaminated fish (methyl mercury)
Dental amalgrams/workers (metallic)
How does mercury cause it’s effects?
Similar to lead
Where are skin cancers caused by arsenic exposure usually found?
Palms and soles
What kinda of cancer is arsenic known to give rise to? 3
Skin
Lung
Bladder
What are the effects associated with arsenic exposure? 4
- Neurologic: sensorimotor neuropathy
- CVD: HTN and prolonged QT interval
3.skin changes: hyperpigmentation/hyperkeratosis - Cancers
What are the most toxic forms of arsenic? 3
Arsenic trioxide
Sodium arsenite
Arsenic trichloride
How does arsenic cause it’s effects (mechanism)
Inhibits oxidative phosphorylation in mitochondria (trivalent arsenic replaces P in ATP)
What is nicotine? How does it work?
Alkaloid substance found in tobacco leaves
Binds to nicotinic acetyl choline receptors in brain to release catecholamines–> increase HR, BP, cardiac contractility
Smoking: Which components are involved in development of lung cancer? 2
Polycyclic hydrocarbons
Nitrosamines
What are the fetal risks of maternal smoking?
Spontaneous abortion
Preterm birth
Intrauterine growth retardation
What are the 3 enzymes that metabolize ethanol?
Catalase
Cytochrome P450
Alcohol dehydrogenase
A blood alcohol concentration of 80mh/dL is reached after how many SD drinks?
3
Where is alcohol dehydrogenase located?
Cytosol of hepatocytes
Which cytochrome P450 isotype metabolizes ethanol?
CYP2E1
What does acetaldehyde metabolize into?
Acetate/acitic acid
Why is fat accumulated in liver of alcoholics?
Alcohol dehydrogenase causes NAD reduction (increase in NADH)
NAD is needed for FA oxidisation in liver and to convert Lactate to pyruvate
What is the main nutritional deficiency in alcoholics?
Thiamine B1