3 - Environmental Diseases I.docx

OS 230: Environmental Diseases I Xenobiotics Exogenous chemicals May be absorbed through inhalation, ingestion, or skin contact Chemical fate Excreted in urine or feces Eliminated in expired air Accumulate in bone, fat, brain, or other tissues Drug metabolization Phase 1 Active form Phase 2 Turned i...

OS 230: Environmental Diseases I Xenobiotics Exogenous chemicals May be absorbed through inhalation, ingestion, or skin contact Chemical fate Excreted in urine or feces Eliminated in expired air Accumulate in bone, fat, brain, or other tissues Drug metabolization Phase 1 Active form Phase 2 Turned into water soluble compounds for excretion P-450 Most important enzyme family involved in phase I reactions Catalyzes reactions Detoxifies xenobiotics Activate them into active compounds Activation of toxic and therapeutic chemicals Generation of a DNA-binding metabolite from benzo[a]pyrene (BaP) Carcinogen present in cigarettes smoke Metabolism of acetylsalicylic acid (aspirin) Phase 2 puts on polar group to make it soluble Alcohol metabolism Pollutants Carbon monoxide 250X stronger binding to hemoglobin than O2 Skin and Mucous membranes become cherry red when poisoning Ozone Sulfur dioxide Nitrogen dioxide Heavy metals Considered heavy metals if 5x water density Lead Microcytic hypochromic anemia with basophilic stippling of red blood cells Microscopic description of early signs Excess lead taken up by bones and developing teeth Forms Burton’s line in the bones and gingiva Interferes with bone remodelling Mercury Very little free mercury in dental amalgam FDA and ADA affirm amalgam is safe and effective Arsenic Cadmium Industrial exposures Formaldehyde Biopsy fixative Bisphenol A (BPA) Found in plastic water bottles Endocrine disruption Chronic alcohol consumption Fatty liver, alcoholic hepatitis, cirrhosis NAD consumed in alcohol metabolism NAD required for fatty acid metabolism Lack of NAD increases fatty acid synthesis Peripheral neuropathy and deficiency syndromes Increased risk cancers of the oral cavity, esophagus, liver, and breast Alcohol’s effect on the liver Fatty change Enlarged liver Alcohol hepatitis (10%-15%) Alcoholic cirrhosis Disruption in architecture Bridging fibrous septa, Irregular pattern, Jigsaw puzzle, … Wernicke’s syndrome Thiamine (vitamin B1) deficiency Cofactor required in carb metabolism Common among alcoholics due to malnutrition Confusion, ataxia, and diplopia from ophthalmoplegia