Environmental Lecture 1 Flashcards
Environmental and Occupational Health Encompasses?
Diagnosis
Treatment
Prevention (of injuries and illness related from exposure to exogenous chemical or physical agents)
Environmental and Occupational Health Exposure?
Workplace
Therapeutic and nontherapeutic drug consumption
Recognition Environmental and Occupational Health Diseases?
Accidents, illness, premature deaths
- Occur: mining, ag, construction, transportation and public utility
Environmental and Occupational Health ratios?
Injuries: 7400/100,000
Death: 4.8/100,000
Health Effects of Climate Changes
Human activity:
- Since 1960, 0.6 C
- Sea level has risen 1-2 mm/year
- Increase in carbon dioxide, methane, ozone (greenhouse effects)
Diseases related to climate changes?
Cardiovascular, cerebro-vascular, and respiratory disease (heat waves, air pollution)
Gastroenteritis and infectious disease epidemics (water and food contamination –> floods, disruption of clean water supplies)
Vector-borne infectious disease (malaria, west nile infection)
Malnutrition (disruption of crops)
Toxicity of chemical agents
100,000 different chemicals in commercial use in the US
- 10% of 600 tested cause cancer
- Waste sites: 4 billion pounds of toxic chemicals (72 million pounds are carcinogens)
Regulatory Agencies
Environmental Protection Agency
FDA
Occupational Safety and Health Administration
Consumer Products Safety Commision
Environmental Protection Agency
Regulates exposure to pesticides, toxic chemicals, water, and air pollutants and hazardous waste
FDA
Regulates drugs, medical devices, food additives and cosmetics
Occupational Safety and Health Administration
Mandates that employers provide safe working conditions for employees
Consumer Products Safety Commisions
Regulates all other products sold for use in homes, schools or recreations
Physicians
Should be familiar with regulatory agencies in US
- Explain the evidence in nontechnical terms
Health care providers
Cousel patients on prevention
tobacco smoking prevention 80-90% lung cancer
Toxicology
Scientific discipline that studies the distribution, effects and MOA of toxic agent
Toxicity
Degree to which a drug is able to produce illness or damage to an exposed organism
Depends on: inherent strucuture/properties and dose
Dose-Response Curve
Subthreshold dose: safe dose
Threshold dose: begin response
Ceiling effect: plateau
Xenobiotics
- “Foreign agents”
Exogenous chemicals in the environment (air, water, food and soil)
Absorbed into the body through inhalation, ingestion and skin contact
Xenbiotic metabolism non-toxic
Phase 1 (hydrolysis, reduction, oxidation) Phase 2 (sulfation, methylation, conjugation) --> more water soluble leading to elimination
Xenobiotic metabolism toxic
Nontoxic metabolite –> reactive metabolite –> effects on cellular molecules (enzymes, receptors, etc) –> toxicity
Personal exposures
Tobacco Use
Alcohol Abuse
Drug Abuse
Tobacco Use
Cigarettes, cigars, pipes, snuff
Deaths: 440,000 per year
Diseases: 10,000,000 cases of chronic diseases, increased morality and morbidity (lung cancer, cardiovascular disease, chronic respiratory disease)
Cigarette smoke consists of two phases?
Particulate phase (tar) 4,000 constituents (43 are carcinogens) Gas phase - chemical and metal (arsenic, nickel and cadmium) carcinogens, tumor promoters (acetaldehyde and chromium), irritants (NO2, formaldehyde) and cilia toxins (H cyanide), CO (binds hb --> less O2 delivery), and nicotine (alkaloid readily crosses BBB, stimulates nicotine receptors in the brain)
Tobacco addiction
Increases: heart rate, bp, coronary artery blood flow, contracitility and cardiac output
Routes of delivery for smoke
Mucous membranes
Swallowed in salvia
Alveolar capillary bed –> bloodstream
Bad stuff of smoke
Act on distant target organs --> cause variety of systemic disease Common disease (lung cancer, artery disease, etc) Effects of fetus: hypoxia --> low birth weight, prematurity, spontaneous abortions, complication at delivery Second hand smoke
Alcohol abuse
More than 10 million chronic alcoholics
More than 100,000 deaths
Results in psychological and physical dependence
Effects: depends on ethanol consumed/unit of body weight + time period in which it is ingested
Blood concentration
Amount exhaled depnds on blood concentration
- 80-100 g/dL –> DUI
2 oz of ethanol in a 70 kg persons ( 15 oz of wine, 3 12 oz beers, 4-5 oz 80-proof whiskey)
Occasional drinkers
200 mg/dL –> drowsiness
300 mg/dL –> stupor
>300 mg/dL –> coma, respiratory arrest, consequent death
Habitual drinkers
Up to 700 mg/dL –> accelerated metabolism, induction of CYPs
Metabolism of ethanol
Liver
Ethanol to acetaldehyde via ADH (alcohol DH)
- enter microsomes via CYP 2E1
- enters peroxisomes via catalase
- enter mitochondria via acetaldehyde DH into acetic acid
Alcohol oxidation by ADH
Decrease NAD and increases NADH
- NAD required for fatty oxidation in liver and conversion of lactate to pyruvate - fatty acid and lactic acidosis in alcoholics
Metabolism of CYP2E1 produces
ROS - lipid peroxidation of cell membrane – cellular injury
Chronic alcoholism causes
cirrhosis of liver, bleeding from gastric ulcers, thiamine deficiency
Alcohol in pregnancy
Fetal alcohol syndrome
Laryngeal and esophageal cancer
Due to acetaldehyde DNA adducts
Acetaldehyde
Carcinogen that can attack the DNA and cause cancer
Asians
Genetic polymorphism: aldehyde DHase that affects ethanol metabolism: Low ALDH activity –> increased acetaldehyde (facial flushing syndrome)
