HLTHAGE 4Z06 Lecture Notes - Lecture 4: Acne Vulgaris, Chlordane, Lipophilicity

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Published on 19 Apr 2013
School
McMaster University
Department
Health, Aging and Society
Course
HLTHAGE 4Z06
Professor
01/30/2008
Human Health and the Environment
Lecture 4: Chemical Hazards and Human Health
From Last Class
Transformation of nitrates to nitrites – in the book it says that it is happening in
our body, professor said here in class that it is happening in water (both things
are true)
It actually depends if we have bacteria to do this transformation process in water
We always have them in our body but if we have in water this process will
definitely happen
Other thing is what is the temperature of the water – if it gets warmer this
process will speed up - i.e. reheating spinach, if spinach is fertilized heavily with
nitrogen fertilizers definitely will at least have high amount of nitrogen – nitrates
When we first eat it fresh it won’t be very dangerous for us – not a risk
But if we reheat that spinach process transformation between nitrates and
nitrites will speed up because of that heat
Chemical Hazards
Why chemical hazards all contaminants all pollutants that we discussed until
now are basically chemical hazards – in water, in air
This lecture will be about the chemical hazards that are spread everywhere – in
every medium be soil, food, plants, meat, water, even in air
Endocrine disruptors
Chemical body burdens of industrial chemicals
Some chemicals that are body burdens are also endocrine disruptors and on the
other hand endocrine disruptors can accumulate in the body and we call them
body burdens and they also do the same in industrial because endocrine
disruptors can be industrial
What is the biggest problem with these chemicals? We don’t know much about it
especially not how these chemicals affect human health
Most of our conclusions are assumptions or they are based on animal studies –
many experimental animals have a similar physiology with humans but not the
same and who knows
That is what we have right now and science is working on that very hard so soon
we will have some better answers
What are Endocrine disruptors?
First you have to know what endocrine glands are
Picture posted to show what are the endocrine glands – these organs in our body
produce hormones
What are the hormones? Chemicals that regulate many different processes that
are very important processes in our body and they regulate the processes in
very tiny amounts
What do endocrine disruptors do to these functions? Hormones are carried
through our body by some receptor also some chemical that carry the hormone
Because of the similarity between the hormone and our pollutant our endocrine
disruptor receptor is confused
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01/30/2008
What is happening? Some genes can be altered because these receptors bind
with DNA and alter the appearance of the gene
What the genes do is regulate the production of different proteins and as a result
of their changes and alterations so changes are reliable to produce proteins are
seen in a body – that is all about direct effects
Also there are many types of indirect affects – production of the hormones,
metabolism of the hormones, transport of the hormones through the body
What is specific for endocrine disruptors? Adults are not that sensitive (adverse
affects are not very visible on adults), fetuses are much more sensitive
Fetuses are more sensitive on the changes of the hormones than adults
Thyroid hormone affects mental brain development of fetuses
DES (diethylstilbestrol)
Problems are not seen if a pregnant mother is exposed to endocrine disruptor –
not much problems can be seen to your health
But the problem is changes in health and life of daughters and sons – we have to
wait 20 to 30 years to see this adverse affect until the daughter or son reach
maturity to have own kids
An example of this is DES, a synthetic estrogen hormone that physicians
prescribe to prevent spontaneous abortion
Lasted for almost 30 years from 1948 to 1971
More than one million women took this in a period of ten years from 1960 to
1970
During the 1980s started facing significant increases in some health problems
such as reproduction organ dysfunction, abnormal pregnancies in daughters,
reduction in fertility when daughters and sons try to have their own kids,
immune system disorders, and some type of carcinoma (adenocarcinoma)
This is lack of knowledge in a time when some medication is prescribed (when
we discuss risk assessment later we will come back to this problem again)
Mothers didn’t suffer that much but kids did
Endocrine disruptors – Health Implications
Other problems with the endocrine disruptors affects our health – feminization of
the males, some strange abnormal sexual behaviour, birth defects, cancer,
altered time to puberty, and thyroid dysfunction especially PCBs affect function
of the thyroid gland
Endocrine disruptors – neurobehavioural effects
Besides these factors, affects on a sexual behaviour and sexual problems neural
behavioural affects are also seen
As a result of prenatal or postnatal exposure
What is the postnatal exposure? Mostly from the breast milk and other
exposures
Gave example of PCBs – PCBs can greatly affect thyroid function but later as a
neural behaviour affect can be some problem with mental developments of the
kids, learning disabilities, some poor IQ tests later in life
In animal studies some impaired learning in non-human primates seen
Organophosphates affect directly brain development
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Document Summary

From last class: transformation of nitrates to nitrites in the book it says that it is happening in our body, professor said here in class that it is happening in water (both things are true) What are endocrine disruptors: picture posted to show what are the endocrine glands these organs in our body. Hormones are carried through our body by some receptor also some chemical that carry the hormone: because of the similarity between the hormone and our pollutant our endocrine disruptor receptor is confused. Adults are not that sensitive (adverse affects are not very visible on adults), fetuses are much more sensitive. Fetuses are more sensitive on the changes of the hormones than adults: thyroid hormone affects mental brain development of fetuses. Lasted for almost 30 years from 1948 to 1971: more than one million women took this in a period of ten years from 1960 to.

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