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Environmental Health Concepts Exam 1 Part 2

Terms in this set (47)

target site
once an organism has been exposed to a toxicant, the compound must get into the body and to its target site in an active form to cause an effect
target organ or target tissue
site of action
What determines toxicity
the concentration of a toxicant at the sites of action
target tissue is not necessarily where a chemical is most highly concentrated
blood can be a target site
Indirect toxic responses
can occur at distant sites from the target site
Where the same dose of two chemicals can produce vastly different concentrations in target tissues
due to disposition
disposition: ADME
absorption
distribution
metabolism/biotransformation
excretion
absorption
ability of a compound to enter the blood
low absorption, low concentration at target site
distribution
a chemical translocates throughout the body
distribution results in non target storage.
metabolism/biotransformation
changing the chemical and biological properties of compounds
excretion
elimination from the body
high excretion, low concentration at target site
uncertainty factors
several factors that address weakness in the data
these factors are compounded
Nanomaterials
behave physically, chemically, and toxicologically in ways that cant be predicted by study of the parent (bulk) material such as gold, titanium dioxide
challenges of nanomaterials
testing every nanomaterial in the body isnt feasible
defining the material to be studied or which characteristics to define is difficult
-lack of standard method for detection and assessment (size and composition are issues)
-carbon needle in a carbon haystack
nanomaterials definition
materials that have at least one dimension in a range of 1-100nm
uses of nanomaterials in consumer products and applications
dry fit socks
carbon bikes
sunscreen
killing tumors
tires
electronics
Epidemiology
the study of distribution and determinants of health related states in specified populations and the application of this study to control health problems
environmental epidemiology
scientific knowledge to understand the effect on human health of physical, biological, and chemical factors in the external environment
molecular epidemiology
study of genetic and environmental factors affecting the distributions and dynamics of health outcomes in populations
genetics
compare population differences in genetic code
epigenetics
change that doesnt alter DNA itself
bias
cause error in outcomes due to deficiencies in study design
selection bias
cant be controlled
must be prevented
people chosen because they already have the disease
observation bias
make sure patient nor data collector know information such as exposure status, diagnosis
confounding bias
inevitable
variables influence each other
cohort study
group of individuals with unusual exposure
followed over time
one exposure evaluated in relation to a number of diseases
prospective: disease hasnt occurred
retrospective: disease already occurred
case control study
tries to determine if current or past exposures may be the source of specific diseases (lung cancer and smoking) evaluates a number of exposures in relation to one disease
stage 1
a pathogen that infects animals, but has not been found to infect humans (rabies, african swine fever)
stage 2
animal pathogen that is transmitted from animals to humans but not between humans (anthrax, hantavirus, west nile virus)
stage 3
animal pathogen that is transmitted between humans but is not sustained in the human population
(ebola, marburg virus)
stage 4
an animal pathogen that is naturally transmitted to humans, and is able to be transmitted between humans for long periods of time without animal hosts (dengue, influenza, chagas disease, cholera)
stage 5
a pathogen that is transmitted and sustained by humans (HIV 1, measles, malaria)
African Swine Fever
stage 1
emergence: viral disease of pigs in Africa
Transmission: domestic pigs, wild boar, warthogs
Severity: death in 7-10 days
Chagas disease
stage 4
emergence: protozoan parasite mostly in latin America
transmission: raccoons, rodents, skunks, armadillos
severity: heart failure and gastrointestinal complications
Anthrax
stage 2
emergence: wildlife populations worldwide, humans in agrarian and developing nations
Transmission: soil bacterium Bacillus Anthracis
Severity: severe; survives outside of host
hantavirus
stage 2
emergence: mostly in south and central america
transmission: rodents, shrews, bats via inhaling host droppings and urine
severity: 37% fatality. flu like hantavirus pulmonary syndrome or hemorrhagic fever with renal syndrome
Leptospirosis
emergence; pathogenic spirochete bacteria of genus leptospira
transmission: domestic and wild animals carry the bacteria such as cattle, horses, pigs, dogs, rodents
Severity: phase 1 similar to flu, phase 2 organ failure, meningitis, Weils disease
neglected tropical disease
communicable diseases in tropical and subtropical areas
usually disadvantaged populations without adequate shelter
livestock exposure and lack of water/sanitation
Septic systems
major source of emerging contaminants in drinking water
they are negatively affecting sources of drinking water
not regulated by EPA
consumer product chemicals (hormone disrupters) removed acetophinomen and caffeine within soil.
soil filters out some emerging contaminants before reaching groundwater
chloroform toxicity
a non monotonic dose response where there is a high response with a low dose
Consequence of benzo(a) pyrene causing DNA adducts
It inserts oxygen atoms as part of the metabolism process. The oxygen likes to go find other electrons (found in the DNA) and they cause mutations. We have good repair systems but when continuously bombarding the DNA, the mistakes can be missed and cancer can occur.
dose response
higher the dose, higher the response
target sites and toxicity
in order for a toxic compound to have an effect, it has to be absorbed in a certain way and distributed within the body where the toxin causes toxicity
ex. botox doesnt affect a person in small doses in the face
biotransformation & metabolism
to excrete easier, things should be water soluble
enzymes are important in this step
you can metabolize something to be more toxic
pharmaceuticals are modified to be targeted by certain enzymes to control the metabolism of a drug
factors affecting biotransformation
-species specificity: variable levels of certain enzymes
-individual susceptibility: babies dont automatically metabolize enzymes. with age you lose the capability to metabolize as well as before
-Interaction of mutliple compounds: alcohol and tylenol are metabolized by the same enzymes so one would be prioritized over the over.
acetaminophen
tylenol.
reactive intermediate (NAPQ) is the parent compound. For the final step of metabolism to occur, it has to go through this step. It happens rapidly and if short lived, it is not toxic. If a person takes too much tylenol then the reactive intermediate hangs around and will bind to the proteins of the liver destroying them
epigenetic modifications: DNA methylation
when a gene gets methylated, the gene cant be turned on or off and can result in cancer
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