Exam 4 Flashcards
what are the Metal distribution categories
Geological, Biological, Anthropological
what are the 2 binding sites of heavy metals?
SH or carboxyl groups, cation binding sites
in what places in the body are heavy metals accumulated?
bone, liver, and kidneys
what is the reactive form of heavy metals?
free metal
when is a metal in its transport form?
bound
Risk groups or concerns of heavy metal tox
children, those frequently drinking milk
why are children more at risk for heavy metal poisoning?
bones are still growing/more fragile, have an immature BBB, have an increased GI absorbtion
what are heavy metal tox treatments?
chelators
3 examples of chelators
EDTA, BAL, DMSA
3 challenges of heavy metal tox treatment
inherent toxicity (like BAL), can bind and remove essential metals (EDTA), can increase toxicity (contamination)
symptoms of mercury poisoning
- CNS/PNS degeneration
- tingling/numbness
- impaired motor functions
- impaired vision/speech
what was released in Minamata Bay (1925)?
mercuric chloride (HgCl2)
what happened to the mercury released in minamata bay?
was quickly methylated to methyl Hg via aquatic bacteria
itai-itai disease is caused by what?
cadmium
3 symptoms of itai-itai
- soft fragile bones
- excessive osteon production
- very thin renal cortex
A kidney/liver protein that is capable of binding and sequestering metal ions, particularly those that are toxic to cells such as cadmium, zinc, and copper
metallothionein
4 types of radiation
- α particles
- charged particles
- 𝛾 rays
- X-rays
what are the 2 charged particle radiation forms?
β particles and positrons
this is the result of atomic decay (i.e. particle loss)
ionizing radiation
3 sources of ionizing radiation
- α particle loss
- Nuclear release of energy (𝛾 rays)
- Inner-shell orbital electrons removed (X-rays)
this occurs when radiation causes a transfer of energy to biological systems, resulting in an effect
Energy deposition
primarily calculated as the amount of energy absorbed; “D=e/m”
Radiation dosage
a weighted dosage based on the type of radiation or the absorption ability of certain tissues
Effective dosage (He)
radiation type weighting from highest to lowest
α > 𝛾 or X-rays
absorption ability weighting from highest to lowest
gonads > bone marrow > skin
these are numbers given to certain factors to determine the actual effect of energy deposited in tissues
Weighing factors
1 J/kg; units of absorbed dosage
Grays
Effective dosage of Grays
Sieverts
what is the Risk of cancer for radiation exposure
about 4-5% per Sievert of dosage
what is the average Background radiation exposure
about 2 mSv per year
4 sources of Background radiation
- Cosmic radiation
- Terrestrial radiation
- Internal emitters
- Major background exposure
Terrestrial radiation examples
uranium & potassium
Internal emitters example
potassium
Major background exposure examples
radon/radium
Lifetime exposure (85 years) of radiation for lung, bone marrow, body
180, 10, 260 mSv
DNA damage can lead to what outcomes:
repair, lethality, mutations
ionizations from energy deposition occur in the genome at what percentage
1%
Stochastic effects of irradiation
DNA strand breaks, mitosis susceptibility
4 Non-stochastic effects of irradiation
- blebbing plasma membrane
- membrane permeability
- cell death/necrosis
- tissue damage
4 Susceptible tissues to Non-stochastic effects of irradiation
- GI
- neuromuscular
- Hemopoietic system
- neurons/CNS
a toxicant response that is very similar to “essential” toxicants (high dose and very low doses have high lethality)
Hormesis
this is a complex, bitter organic compound that contain nitrogen and usually oxygen
Alkaloids
Alkaloids mainly occur in what?
seed plants
5 Alkali-like substances
nicotine, atropine, cocaine, novocaine, morphine
Morphine mechanism of action in the cell?
leads to membrane hyperpolarization via K+ channel opening
what toxicant response is the most common in plant tox?
local tox
GI local tox of plant toxicants symptoms
nausea, vomiting, diarrhea, poor absorption, gastroenteritis, dehydration
4 plants that cause GI local tox
- California Buckthorn
- Horse chestnut
- Ohio Buckeye
- Autumn crocus
3 GI local plant toxins
emodin, esculin, and colchicine
responses to skin irritation from plant local tox
nerve desensitization, contact dermatitis, inflammatory
4 plants that cause skin irritation
- Spurge family
- Philodendron
- poison ivy
- stinging nettles
6 skin irritants plant toxins
latex, diterpene, resorcinols, catechols, histamine, NTMs
types of systemic tox responses to plant toxins
cardiac tox, nervous system tox
Na/K ATPase disfunction = cardiac arrhythmia
Foxglove
Foxglove toxin
digitalis
nicotinic ACh antagonist = diaphragm paralysis
Chondrodendron
muscarinic antagonist = CNS, pupil dilation
Bellodona, nightshade
Bellodona, nightshade toxin
atropine
Chondrodendron toxin
curare
the result of “dirty” coal burning that released massive amounts of sulfur dioxide into the air
London ‘fog’ of 1952
Five major gaseous/toxic pollutants
SO2, NO2, O3, CO, Fluoride
Health + environmental effects of SO2
depletes soil calcium, decreases plant growth, pulmonary irritant
Health + environmental effects of NO2
pulmonary irritant
Health + environmental effects of O3
respiratory and eye irritant, protein and AA changes
Health + environmental effects of CO2
high-affinity heme binding
Health + environmental effects of fluoride
gastroenteritis, weakness, dental fluorosis, skeletal fluorosis
good! Provides UV protection from the sun
Upper atmosphere ozone
bad! Formed from reactions between VOCs and nitrogen oxides (NOx) with sunlight
Ground-level ozone
3 Indoor pollution sources
cigarette smoke, formaldehyde, and radon gas
members of a single species that live in the same place
Population
all the species that live in an ecosystem
Community
biotic and abiotic components and their interactions
Ecosystem
high population growth (r), low survival to adulthood, short lifespan, oscillating population
R-strategists
low population growth, high adulthood survival, long lifespans, steady population at carrying capacity (K)
K-strategists
following a toxic insult which strategist rebounds faster?
r-strategists rebound much faster
3 Density-dependent factors
resources, predation, disease
3 Density-independent factors
weather, seasonal changes, direct-acting toxicants
concentration in the organism / environment concentration
Bioconcentration (BF)
cultures in test water, seed germination in test soils (highest control)
Lab Bioassay
Lab Bioassay specimens
daphnia, shrimp, bees, quail, trout, fathead minnows
Bioconcentration (BF) of lipophilic compounds
higher
Bioconcentration (BF) of metals
low
studies that involve caged fish, earthworm canisters
Field Bioassay
study type that involves tissue analysis of field-collected organisms
Field specimens
study type that involves field observation and measurements of environment
Field studies
things observed in a field study test
Abundance, productivity, and community structures & relate them to tox gradients in the ecosystem
observation of a natural population member like groundhogs or marmots in their natural habitat
Endemic Indicators
this includes species attractions to (likely toxic) environments to observe them (European starlings with nest boxes)
Enhanced Indicators
specimens are kept in a contained area and treated with various toxicants to observe the responses in a relatively uncontrolled environment
Enclosed Indicators
this clause prohibits the FDA approval of food additives that were found to induce cancer when ingested by humans or animals
Delaney clause
generally recognized as safe
GRAS
Direct Food Additives examples
anticakers, processing aids, colors, flavors, etc
materials that were either unintentionally added to foods or were never removed from the food
Unintentional
Unintentional Food Additives wxamples
Herbicides, pesticides, antibiotics, anabolic agents, therapeutic drugs, residues
materials present in food due to environmental pollution or faulty handling of the foods
Contaminants
3 food Contaminants types
Biological
Metals
Synthetics
synthetic food additives examples
PCBs or PBBs
sources of lead food contaminants
lead crystals, ceramics, ‘tin’ cans
a biological food contaminant considered to be a mycotoxin
aflatoxin B1