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Challenges to Biomedical Research

(Student Guided Notes) updated 5.2012

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BT11.01Interpret personal beliefs about

biomedical research.

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A.Personal Beliefs About Biomedical

Research

1. There are different beliefs about biomedical research and they vary widely.2. What is the difference between fact,

opinions and myths

(Activity in NCABR: Unit III Ch. 1 page 1.3; 1.8 and 1.13)

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Biotechnology • Biotechnology is basically

known as the recreation and reinvention of nature. It deals with the _______________ of living organisms in order to make or improve products, enhance plants and animals or generate ______________ to make human life and the environment better. Biotechnology has been practiced for ___________ of years. It dates back to when man first learned how to plant crops or breed animals.

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BT11.02

Analyze transgenic animals

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Transgenic Animals

Biotechnology- collection of scientific ___________ that use living cells and molecules to __________ products and _____________ problems.

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Transgenic Organisms Plant, animal, or

bacteria that has been ________ ____________to contain _________ species’ genes within their chromosomes.

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This is accomplished by _____________ specific genes from one species to another.

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A.Early Beginnings:

Streptococcus lactis and other lactic acid bacteria are used to make cheese. They ripen the cheese and provide characteristic flavour.

Historically- used in selective breeding of livestock, controlled plant pollination, and _________________ to bake _________, brew beer, and make __________.

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Early Beginnings: (cont.)

First, transgenic

organisms were

_______________.

Remember the

bread, beer and

cheese? What about

a few of these other

items?

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Transgenic Organisms

• The first transgenic organisms were bacteria and were created in a _________________!

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BACTERIA

• Pharmaceutical companies use ___________ to produce insulin, human growth hormone, interferons to treat cancer.

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The technologies used to produce transgenic animals has become so well defined that scientists around the world use customized transgenic animals for their own research.

- These include: sheep, goats, cows, chickens, pigs, mice, rabbits, rats, and fish.

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Scientific research uses animal models and mice are used most often because they:

• They reproduce quickly• Small and easily housed• Their genetic makeup is easily understood• Their lifespan is 3-4 years so researchers can

follow a disease from infancy to old age quickly• Transgenic mice are used to study cancer,

multiple sclerosis, muscular dystrophy, Alzheimer's and immune deficiencies

B. 1 Benefits of Transgenic Animals:

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____________ are the animals most often used in research

laboratories!

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B.2 Pharmaceutical production or PHARMING

• In the past, drug companies would produce drugs by growing mammalian cells in tissue cultures.

• Now they use ______________ animals to produce more substances used in medicines by introducing the gene into larger farm animals.

• It is more economical than using bacteria in the lab.

• These substances are then used in medicine and it is called ______________________________.

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B.3 Organ Donors –_____________________ -using organs

from other species• When transplanting a

major blood vessel into a patient, what animal was the xenograft from? _________

• _____________ is the biggest challenge with pig organs in human transplants.

• Production of pigs whose organs look more “____________” or “__________” our immune system.

PIGS

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B.4 Livestock improvement

• Agricultural researchers realized that transgenic technology could produce animals that are larger, leaner and more resistant to disease.

• It is very expensive.

• Opposition-Some people are afraid to eat the meat and drink the milk from transgenic livestock.

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Most consumers _____ _____ _____________ to purchase genetically modified produce.

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Genetically Modified Organisms• A newly discovered technique in the

food industry is that of Genetic Modification and GMO's. This is where, through science, a tomato can have a gene from fish added to it to make it have a longer shelf life.

• Also, the same technique can be used to make newly born animals grow quicker and fatter to make more meat more quickly.

• All of this sounds good but by changing the way these organisms are made up, we are altering nature in a very unpredictable and dangerous way.

• We simply do not know what the long term effect will be.

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The following steps are followed to produce a transgenic animal.

C.

Production of Transgenic Animals:

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1. The transgene ( which contains the _________ the scientist wants to transfer) is injected into a _________ _____ _________________.

2. So it is transferred from one organism to another (_______________)

3. The embryo is transferred to a ________________ mother of the same strain who has been given hormones so the eggs can implant and grow.

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Statistics of Transgenic animal success:

4. Success rate is low (10%-30%) in mice• 100 mouse embryos are microinjected• 60% survive and are reimplanted• 30% of these are born (18)• 10-30% of the 18 are actually transgenic- the

transgene successfully copied itself

5. Success rate decreases even more in other mammals because of their size. (cows)

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D. Care of Transgenic Animals

Most do not require special care.

However some develop a susceptibility to disease which then requires special care, food, water, antibiotics, etc.

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E.E.Government’s role in transgenic Government’s role in transgenic

animals:animals:

• Before you create a transgenic animal researchers must apply for a _________ from the __ ___ _______ and ________ Office

• NIH (National Institute of Health) guidelines are the only government policies written for research involving recombinant DNA molecules

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F. Ethical Considerationsof Transgenic Animals

Opposition • Transgenic animals

______________ our environment, health & food safety.

• Some believe we are playing ____________.

• Some believe scientists will use these techniques on __________________.

• There was opposition in 1997 when Dolly the sheep, a mammal was cloned.

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Those in favor, say “Aye”

• Scientist believe that through transgenic animal research:– we will be able to find cures for diseases

• Cancer, sickle cell anemia– medications to save lives– production of organs for transplants– and food to feed the hungry

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G.Future of Transgenic Animals

1. Current research limited to transferring small amount of genes at a time.

2. Much work remains to be done to fine-tune techniques and decrease the risks.

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Future of Transgenic Animals(cont.)

3. Possible effects of foreign DNA remains a concern.

4. The use of “transgenic models” is an ________________ part of biomedical research. It is _________ to stay!

5. This is your future in science.

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Current use of transgenic model

Remember science is always evolving.

Biomedical technology and the use of transgenic animals are vital to our future!!!

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BT11.03Evaluate therapeutic vs.

reproductive cloning

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CLONING

• Cloning may be the most discussed --- and most misunderstood --- issue in

biomedical research today.• What do you think of when asked about

cloning?– Dolly the sheep?– Twins in your neighborhood? 3:1,000 births;

“natural cloning”– Star Wars Episode II: Attack of the Clones?

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So….What is a Clone?

• Clone = precise ______ copy.

3 types of cloning• ________________ DNA Cloning

– Utilizes microorganisms for new products, manipulating DNA-most often uses bacteria

• __________________ Cloning– Reproductive cloning is really somatic cell nuclear

transfer (SCNT) but we usually say the word “Cloning”.

• __________________ Cloning– Embryonic Stem Cell Production

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Cloning

Very few scientists believe human cloning (reproductive cloning) should be permitted.

However most medical scientists support & are in __________ of therapeutic (beneficial) cloning.

Therapeutic Cloning is the procedure used to produce embryonic stem cells that theoretically can be used to treat diseases.

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A.History Of Cloning

• _________ the sheep - First cloned

____________ in 1997.

• She is an example of ___________ Cloning

• She was euthanized in 2003 due to a lung disease.

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Quick Discussion on Reproductive Cloning

(how it is done)• The nucleus is removed from an unfertilized

egg- this is called “enucleated”.• The nucleus of a cell removed from the animal to

be “cloned” is inserted into the enucleated egg.• The reconstituted embryo is then placed in the

uterus of a surrogate mother and carried to full term.

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C.Obstacles to Reproductive Cloning

Using Animals

• The Success rate is very low—3 in 100 cloned embyros

• Vast majority of problems occur during fetal development.

• Additional problems show up after birth and years later.

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Obstacles to Reproductive Cloning Using Animals

“Large Offspring Syndrome”-

Cloned newborns 20-30% larger than usual, making it hard to deliver unborn babies.

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Human Reproductive Cloning(which is not being done in the US today)

• Fyi---don’t take notes, just read

• For human cloning, a female would donate her eggs to be enucleated.

• The nuclei of her cells would be removed and the person being cloned would donate somatic cells for the nuclear transfer.

• A surrogate mother would then accept the fertilized ova in hopes of carrying one to term.

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Status of Human ReproductiveCloning in the World

• There is ________ evidence of _________________human cloning in the world.

• Remember: Reproductive cloning is really somatic cell nuclear transfer (SCNT) but we usually say the word “Cloning”.

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Now to discuss Therapeutic (beneficial) Cloning

• In therapeutic cloning, the embryo is not placed in a surrogate, but rather, undergoes cell division in the lab until it reaches blastocyst stage.

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• This is a procedure that allows a longer time for the embryo to develop in the laboratory (five days instead of two to three) and enables the embryo to reach blastocyst stage. A blastocyst contains 2 layers: the inner mass can form virtually all of the tissues of the body.

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Therapeutic (beneficial) Cloning cont.

• To obtain embryonic stem cells, the blastocyst is opened, and the inner cell mass is placed in tissue culture. – So it is NOT placed in a surrogate; it is placed

in a tissue culture in a lab setting

• In culture, the cells divide and make the exact copies of themselves, forming “clones”. This means MORE embryonic stem cells that can grow into tissues to treat diseases.

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There are 2 classifications of stem cells: adult and embryonic

• Adult Stem Cells are undifferentiated cells, found in small amounts throughout the body after embryonic development, that multiply by cell division to replenish dying cells and regenerate damaged tissues. Most often found in the ________ ____________.

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When would someone need an adult stem cell ______________?

• When _________ treatment for ________ has ____________ the person stem cell’s.– A patient may freeze their own bone marrow

before the radiation treatments and receive a transplant of their own bone marrow which has adult stem cells present. These cells will reproduce RBC, WBC and platelets.

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Embryonic Stem Cells• A recently _____________ egg is “totipotent” which means it has

the potential to become any kind of cell

• During the first rounds of cell division, each cell has the potential to form a fetus (this is how we get identical twins)

• After 4 days, a blastocyst develops- and the inner mass of embyronic stems becomes pluripotent-which means they have the potential to become many types of cells, but no longer every type- which means they can no longer become a fetus.

• Parents of newborns can now bank baby’s umbilical cord blood in case their child needs new stem cells later in life.

• Scientists think these stem cells work better than bone marrow because they are less “mature”.

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Embryonic Stem Cells

• The purpose of performing embryonic

stem cell research is to develop _______ & _____________ ways to treat ___________.

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Embryonic Stem Cells

• Embryonic Stem Cells are the so-called starter cells that can turn into any sort of body tissue, from brain to bone to blood.

• These unspecialized cells can divide for indefinite periods in vitro.

• The scientists hope the embryonic stem cells will generate specific tissues to help repair damaged and diseased organs.

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Why are Stem Cells so important to Medical Researchers?

They are important to medical researchers because they may be used to __________ perfectly __________ _______________ to treat an individual _____________ or disorder.

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E.Differences Between reproductive

and therapeutic cloning:• Reproductive Cloning:

– The Goal of this is to create a new organism, human or other animal.

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• Therapeutic Cloning:– The goal of this is to produce embryonic stem

cells.

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Remember…….

Very few scientists believe human cloning (reproductive cloning) should be permitted.

However most medical scientists ____________ & are in favor of ___________ (beneficial) cloning.

Therapeutic Cloning is the procedure used to produce embryonic stem cells that theoretically can be used to treat diseases.

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F.Human Stem Cell Research

• In 2001 legislation allowed federal funding of research using 64 existing human embryonic stem cell lines.

• Same legislation declared no federal funds for any other research or cloning of human embryos for any purposes.

• This decision did not affect research funded by private companies or state government so if a scientist wants to __________ a __________ stem cell line they could with ___________ funding.

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G.Therapeutic Potential of Stem CellsResearchers must use existing human stem

cell lines for research or find private funding resources.

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The creation of embryonic stem cells does not use a fertilized egg.

This method instead uses an unfertilized egg, with its nucleus removed and fuses it with the genetic material from an adult’s body.

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Therapeutic Potential of Stem Cells(cont.)

On the other hand. . . It does have the potential to become a living thing if transplanted into the uterus.

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Question

Is life destroyed if the stem cells are removed from the blastocyst four days later? This is the question at the core of the debate about stem cell research.

As noted in slide 48 a fertilized egg is used but it is allowed to grow to a blastocyst stage.

After 4 days, a blastocyst develops- and the inner mass of embyronic stems becomes pluripotent-which means they have the potential to become many types of cells, but no longer every type- which means they can no longer become a fetus.

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Therapeutic Potential of Stem Cells(cont.)

Real advantage of Stem Cells – Permits the production of perfect-match tissue.

Scientists have found that embryonic stem cells pick up cues from ___________ cells and differentiate into that _______ type.

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Therapeutic Potential of Stem Cells(cont.)

Scientists hope stem cells will be used to treat ________ disease, Parkinson’s and other diseases of the __________ system.

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WHAT IS YOUR OPINION?