L3. Heavy Metals Flashcards

Question

Mercury (Hg) Clinical Effect

Answer 1

* Inorganic: * GI and renal tubular necrosis * Organic: * neurologic fibrinoid degeneration of arterioles, neuronal necrosis → blindness, staggering, incoordination, recumbancy, death

Answer 2

elemental Hg poor GIT absorption, but vapors are absorbed and dangerous Salts and organ mercurial are absorbed in the GIT

Answer 3

kidney → urine; fecal; lungs

Answer 4

**_Primary targets are the kidneys and CNS_** Bind to sulfhydryl groups Inhibits enzymes and protein synthesis Inhibit mitochondrial function by binding to alpha lipoic acid and thioctic acid Sulfer containing organic acid cofactor involved in aerobic mtabolism Pyruvate dehydrogenase complex

Answer 5

Whole Blood \>1ppm LIver kidney hair urine feeds

Answer 6

Acute Exposure: egg white, activated charcoal; sodium thiosulfate Saline cathartic or sorbitol Oral penicillamine orally DMSA Chronic organic - Se, Vitamin E

Answer 7

Bioaccumulation and bio magnification int he food chain Sediments → fish → mammals, including humans Hg residues in kidney and muscle tissue, currently most concern in fish Higher concentrations range form 0.7-1.5 ppm

Answer 8

Discovered in 1861 by Sir Williams Crooks 1862 by French Chemistr Claude-Auguste Lamy In Greek, *Thallos* “green twig” Monovalent and trivalent salts are very toxic Elementary Tl is non toxic

Answer 9

Thallic +3 oxidation state Thallous +1 oxidation state

Answer 10

World production is 12 tons/year Emissions 1500 tons/year in granite and coal Semiconductors, photocells, optic glass, thermometers Tl201 radiocative tracer used in heart scintigraphy to detect myocardial ischemia Occurs with other minerals Heavy Metals: Very toxic and highly comulative Rodenticide: 1920's-60's: tasteless, oderless, easily masked in baits Once used as a depilatory Off the market since 1965 Occasional exposure form old products, cleanout of buildings

Answer 11

Half life is 1-30 days Similarities in charge between K+ (Tl will substitutes for K+) 1) Blocks energy utilization by Na-K ATPase channel; blocks active transport of K+ across the cell membrane Tl ahs a 10 fold greater affinity than K+ in neuronal, cardiac and skeletal muscle cells 2) Blocks energy production from glucose: ADP to ATP by pyruvate kinase = K requiring enzyme Inhibition by binding with 50 fold affinity compared to K+ 3) Damages riboflavin, forming and insoluble complex and intracellular sequestration of Vitamin B6 4) Binds to SH groups and interferes with formation of disulphide bonds in heratin, structural damage to hair and nails → depilatory 5) causes activation or inhibition of other enzymes

Answer 12

Multisystemic Disease: * Gi necorsis - similar to arsenic, severe hemorrhagic gastritis, congested oral mucosa * Neurologic - trembling, motor paralysis, mental retardation * Alopecia and skin sloughing form 7 days to 2-3 weeks after ingestion, renal and liver injury * Blindness

Answer 13

Urine thallium (any concentration is significant) Kidney, liver, feces, Feces

Answer 14

Radiofardase - prussian blue insoluble capsules Treatment is ineffective once clinical signs are apparent Dithizon: specific chelatory fot Tl

Answer 15

Reactive, water soluble non-metal common in nature, but variable in distribution Sources include: Minind deposits Rock phosphate Water form deep wells/geothermal water Industrial pollution

Answer 16

Drinking water and plants Mineral deposits – effluent, tailings Pesticides Product of industrial processing of aluminum ores or phosphate fertilizers Fertilizers and calcium/phosphate minerals must be deflourinated Past history: Aerial contamination form aluminum smelters and steel mills

Answer 17

Affects mineralized tissue — teeth,a nd bone Deposited in hydroxyapatite crystal of bone and distorts normal haversian system remodeling Dental fluorosis si dystrophic formation of dentin and enamel in erupting teeth only

Answer 18

**Chonic Exposure:** Progressive debilitating disease Cattle, horses, wild herbivores **Osteroflourosis:** Bone formation on outside of long bones produces lameness **Dental Fluorsis:** Softening of tooth enamel, early wear Does not readily cross the placenta

Answer 19

Rapidly absorbed; excreted through urine About 50% of asbsorbed dose requesters in bone Mostly in developing/remodeling bone Developing teeth erupted teeth are unaffected

Answer 20

Large, acute exposure cause GI irritation and kidney damage Moderate, chornic exposures are more common, affects bones and developing teeth

Answer 21

History: exposure to feeds, environment Clinical Signs: **Lameness**, weight loss, elongated hooves, **Lapping water** Lesions: Dental Fluorosis in erupting teeth **Exostosis of limbs, ribs, mandible** Fl analysis: uring, bone Feed, water

Answer 22

No Specific Treatment Poor prognosis Pain management and soft feed may allow salvage following extended recovery periods Avoid exposure Aluminum or Ca-carbonate at 1% of diet will reduce fluoride absorption

Answer 23

Best to prevent Environmental impact Food Safety - not significant

Answer 24

_Controversial_ 1. Fluoridation is a violation of the individual's right to informed consent to medication 2. Fluoride is not an essential nutrient 3. Hundreds of research articles published over the past several decades have demonstrated potential harm to humans form fluoride at various levels of exposure, including levels currently deemed as safe 4. It also poses threats to animals as wellas the environment as large

L3. Heavy Metals Flashcards

(48 cards)