Chapter 8 - Technology is used to treat diseases Flashcards
What is Biotechnology?
DEFINITION: The use of biological processes to produce useful products.
- Uses CELLULAR PROCESSES to make PRODUCTS that are of use to Humans.
- used to IMPROVE HUMAN WELFARE
What does modern Biotechnology encompass?
What does it improve for human welfare?
- expanded to include genetic testing, gene manipulation, cell replacement therapies including tissue engineering
used to improve human welfare
- Treatment and prevention of disease
- food production
- production of clean energy
- enhanced efficiency of manufacturing processes
What is DNA and where is it found?
WHAT IS DNA’S APPROXIMATE LENGTH?
- Deoxyribose nucleic acid
- usually in NUCLEUS but some found in the MITOCHONDRIA
- in SOME organisms in CYTOSOL
The average length of DNA molecule that makes up a HUMAN CHROMOSOME is 140 MILLION BASE PAIRS.
Explain the Structure of DNA
Made up of 1000s of NUCLEOTIDES
Each nucleotide consists of:
- DEOXYRIBOSE (a 5-carbon sugar)
- PHOSPHATE GROUP
- NITROGENOUS BASE (the base that contains nitrogen atoms)
NUCLEOTIDES are JOINED in such a way that the ALTERNATING SUGARS and PHOSPHATES form 2 CHAINS that are LINKED BY the NITROGENOUS BASES.
- THE BASES FROM 2 STRANDS ARE ATTRACTED TO ONE ANOTHER BY WEAK HYDROGEN BONDS, FORMING A CRISS-CROSS LINK BETWEEN THE 2 STRANDS.
The TWO CHAINS ARE TWISTED INTO A SPIRAL SHAPE KNOWN AS A DOUBLE HELIX.
- ALTERNATING SUGAR PHOSPHATE BACKBONE JOINED VIA COMPLEMENTARY NITROGENOUS BASES WHICH BRANCH OF AT EACH SUGAR MOLECULE
What are the 4 bases?
What is the Base pairing rule?
How are they Joined?
WHY IS THE BASE PAIRING IMPORTANT?
ADENINE (A) THYMINE (T) CYTOSINE (C) GUANINE (G) protein synthesis uracil is changed with T
THEY ARE COMPLEMENTARY
A -T
G-C
THE BASES FROM 2 STRANDS ARE ATTRACTED TO ONE ANOTHER BY WEAK HYDROGEN BONDS, FORMING A CRISS-CROSS LINK BETWEEN THE 2 STRANDS.
THE ORDER IN WHICH THE NITROGEN BASES OCCUR IN THE DNA MOLECULE IS THE GENETIC INFORMATION THAT DETERMINES THE **STRUCTURE OF THE CELL AND THE **WAY IT FUNCTIONS
What is artificial selection or selective breeding?
An ancient form of genetic engineering where humans select desired traits and choose parents bases on these traits.
- increasing the chance of the gene for those phenotypes desired to be passed on to offspring.
- INCREASE/DECREASE INCIDENCE of certain GENES.
Quite slow and INEFFICIENT PROCESS
- Genes are passed on BY CHANCE: probability is increased but not definitive
- necessary to WAIT for the NEXT GEN. to MATURE before KNOWING THE OUTCOME.
What is Genetic Engineering?
also known as RECOMBINANT DNA TECHNOLOGY
DEFINITION: the procedures used to produce recombinant DNA; involve introducing DNA into a cell from a different type of organism or DNA that has been modified in some way.
DNA IS EITHER ADDED OR REMOVED FROM A CELL.
THE DNA PRODUCED IS RECOMBINANT DNA
What is RECOMBINANT DNA?
definition: Synthetic DNA; made by inserting genes from one source into a DNA molecule from a different source.
What is a GENETICALLY MODIFIED ORGANISM (GMO)
An organism produced by genetic engineering
- All transgenic organisms are GMOs, but not all GMOs ARE TRANSGENIC
List some ways in which GMOs can be produced using recombinant DNA technology.
- introducing genes for desired traits into organisms
- using harmless bacteria to produce proteins and replacing faulty genes
What is a TRANSGENIC ORGANISM?
AIM
EXAMPLE
DEFINITION An organism that has had DNA from ANOTHER SPECIES INTRODUCED into it ARTIFICIALLY.
AIM:
- introduce a trait that is not normally present
EXAMPLE
- GOLDEN RICE; developed to address vitamin A deficiency in developing countries
- the deficiency kills 670 000 children under the age of 5 every year
- PRODUCED BY INTRODUCING A GENE FROM MAIZE AND A BACTERIUM FOUND IN SOIL INTO RICE.
- ALLOWS the rice to PRODUCE BETA-CAROTENE, which the HUMAN BODY CAN USE TO SYNTHESISE VITAMIN
Explain the development of recombinant DNA technique
BY STANLEY NORMAN COHEN & HERBERT BOYER IN 1973
technique:
- ISOLATE and AMPLIFY GENES OR DNA SEGMENTS
- INSERT them into a BACTERIAL CELL = TRANSGENIC BACTERIUM
- INTRODUCED GENES become PART of the TRANSGENIC ORGANISM’S DNA
- CAN BE PASSED FROM ONE GEN. TO NEXT.
What is the process for RECOMBINANT DNA TECHNOLOGY TO BE MADE POSSIBLE?
- GENE of the DESIRED TRAIT MUST BE IDENTIFIED
- THEN ISOLATED
- DNA RECEIVING the gene must be ‘OPENED’
- GENE is then ADDED to the RECIPIENT and JOINS ITS DNA.
What are bacteriophages?
OR PHAGES
A VIRUS that INFECTS BACTERIA
What is the key breakthrough in genetic engineering via the use of phages?
- Discovered that certain enzymes in bacteria are able to restrict the duplication of bacteriophages by cutting up viral DNA.
- these enzymes cut the DNA at a point where there is a certain sequence of bases (RECOGNITION SITE/SEQUENCE)
- enzyme that cuts the DNA is a restriction enzyme because it restricts the duplication of bacteriophages.
What is the recognition site?
vs
What is a recognition sequence?
A specific sequence of nucleotides at which an enzyme cuts a strand of DNA
the sequence of bases in the recognition site.
What is ENDONUCLEASE?
An enzyme that breaks a nucleic acid within the strand by separating 2 nucleotides
EXAMPLE OF A RESTRICTION ENZYME
What is a restriction enzyme?
An enzyme that cuts strands of DNA at a specific sequence of nucleotides
- will cut straight or staggered cut
explain straight cut and blunt end
STRAIGHT CUT:
- A cut produced when a restriction enzyme makes a clean break across the 2 strands of DNA so that the ends terminate in a base pair: called blunt ends
BLUNT ENDS:
- the end produced by a straight cut of a sequence of nucleotide bases
- BOTH STRANDS TERMINATE IN A BASE PAIR
explain staggered cut and sticky end
STAGGERED CUT
- A cut produced by when a restriction enzyme creates fragments of DNA with the unpaired nucleotides that overhang at the break in the strands called sticky ends
STICKY ENDS
- the overhanging end produced by a staggering cut of a sequence of nucleotide bases
- sometimes called COHESIVE END
- IS A STRETCH OF UNPAIRED NUCLEOTIDES IN THE DNA MOLECULE THAT OVERHANG AT THE BREAK IN THE STRANDS
what is Palindromic?
A sequence that reads the same backwards and forwards
What are the properties of a Recognition SITE?
And what does this mean?
- are 4-8 BASE PAIRS IN LENGTH
- PALINDROMIC
This along, with the complementary nature of the bases, means that the same sequence occurs on both strands within the recognition site.
HENCE both strands will be cut resulting in the DNA molecule forming 2 segments
Each restriction enzyme will:
- Recognise a certain base sequence
2. cut at a certain point
What contributes to the type of cut?
EXAMPLES
- CERTAIN BASE SEQUENCE
- ENZYME AND ITS CUTTING STYLE
Xmal enzyme and Smal
- same recognition site
5’ - CCCGGG-3’
Xmal cuts between the first and second nucleotides and PRODUCES STICKY ENDS
Smal Cuts between the third and fourth nucleotides and produces BLUNT ENDS
What the benefit of sticky ends?
- also named due to ABILITY TO COMBINE WITH SECTIONS OF DNA THAT HAVE A COMPLEMENTARY ENDING
- USEFUL in recombinant DNA tech. as they ALLOW a SINGLE -STRANDED COMPLEMENTARY OVERHANG FROM ONE DNA FRAGMENT TO BE PAIRED WITH ANOTHER PIECE OF DNA THAT HAS A CORRESPONDING SEQUENCE
- DNA COULD BE FROM THE SAME OR A DIFFERENT ORGANISM
The name of each RESTRICTION enzyme reflects its origin.
Explain how
- 1st letter of the name comes from the genus of the bacterium from which it was ISOLATED
- 2nd 2 letters come from the species
- Next letter (4th) refers to the STRAIN OF THE BACTERIUM
- the ROMAN NUMERALs represent WHEN the enzyme was ISOLATED, where I is the 1st enzyme isolated, II is the 2nd enzyme isolated etc.
Examples of Enzyme, Recognition site, Bacterial origin
STUDY AND WRITE DOWN TABLE 8.1
Monomer Vs Polymer
Draw nucleotide
Monomer = nucleotide
Polymer = double helix
Purine VS Pyrimidine
Purine = A, G Pyrimidine = T, C
- two-carbon nitrogen ring bases (adenine and guanine) are purines,
- one-carbon nitrogen ring bases (thymine and cytosine) are pyrimidines.
Explain how are why are bases complementary.
COMPLEMENTARY BASES
- shapes differ
- sizes differ
to fit and connect properly in a double helix structure
Gene vs Genetic Code
Triplets?
Genetic code = sequence of bases
Gene = a particular sequence of bases coded for a protein
Simply the steps for Recombinant DNA (SUMMARY)
- DESIRED GENE IS IDENTIFIED, then Segment of DNA is LINED UP
- ISOLATE THE GENE (donor cell) Cut it at the RECOGNITION SITE via RESTRICTION ENZYME
- on either side of the gene - ISOLATE a PLASMID of the vector and CUT IT with the SAME RESTRICTION ENZYME.
- SPLICE (add in) the Human DNA into the PLASMID using DNA LIGASE
- recombine DNA in the double-stranded form = so it fits in - DNA CUT IS REMOVED AND REPLACED with desired FOREIGN DNA
- foreign DNA is ‘GLUED’ in place by DNA LIGASE via the process of LIGATION
- joining the 2 sections together - BACTERIA takes up RECOMBINANT PLASMID DNA and then MULTIPLIES
- via mitosis in the host cell
Benefits of Recombinant DNA
- potential to replace faulty genes with healthy ones
- Identify mutations/carriers of disease
- Introduced genes are PART OF DNA and can be PASSED ONTO GENERATIONS
What is DNA ligase? IN DETAIL
AKA; DNA-JOINING-ENZYME
An enzyme capable of combining 2 small components of single-strand DNA into one single structure.
- able to join, recombine separate pieces of DNA
FOUND IN BACTERIUM ‘ESCHERICHIA COLI’ (E. COLI)
- some version of DNA ligase is used by every living cell to ‘glue’ together short strands of DNA DURING REPLICATION = PROCESS CALLED LIGATION
what is LIGATION?
The process of joining short strands of DNA during replication
Explain what happens in the process of ligation….
- Joins the PHOSPHATE GROUP at the END of ONE STRAND to the SUGAR MOLECULE at the END of another STRAND.
- For this to be possible, the complementary bases must first join by FORMING HYDROGEN BONDS
- Then the DNA ligase can join the BACKBONE of EACH STRAND
What is a Vector?
A bacterial plasmid/viral phage or other such agent used to transfer genetic material from one cell to another.
DNA MOLECULE USED TO CARRY DNA INTO A CELL
What are PLASMIDS
In a bacterial cell, small circular strands of DNA distinct from the main bacterial genome; composed of only a few genes and able to replicate independently within cells
- double-stranded units of cytoplasmic DNA
- Capable of replicating within a cell independently of chromosomal DNA
Why are PLASMIDS important? + EXAMPLE
- bacterial plasmids and bacteriophage viruses are commonly used in Recomb. DNA Tech.
- The gene of interest is integrated into the plasmid or phage = recombinant DNA
- cloning of the vector then occurs so that numerous copies of DNA are available to insert into the HOST CELLS
- Once large quantities of the vector have been produced, they can introduced into the selected cells such as
- YEAST OR MAMMALIAN CELLS - These host cells will then produce the foreign protein using instructions in the gene recomb. DNA
example - BACTERIA INTO WHICH THE GENE FOR INSULIN PRODUCTION HAS BEEN INTRODUCED ARE NOW USED IN THE MANUFACTURE OF INSULIN FOR THE TREATMENT OF DIABETES
Examples of the use of recombinant DNA technology?
What occurred in the past?
- Has made a huge impact on the DIAGNOSIS and TREATMENT of diseases and genetic disorders
- enabled the MANUFACTURE of LARGE QUANTITIES of PURE PROTEIN for many MEDICAL PRODUCTS including
- INSULIN, GROWTH HORMONE, FACTOR VIII, FOLLICLE STIMULATING HORMONE (FSH)
** in the past these substances have been extracted from people or animals, were often impure and/or variable in strength
One example - transmission of the human variant of Creutzfeldt-Jakob disease (vCJD) by contaminated HUMAN GROWTH HORMONE
- this disease is a variant of ‘mad cow disease is a rare but fatal brain infection
- evidence that blood products used to produce the protein FACTOR VIII were contaminated with vCJD
What are recombinant vaccines?
A vaccine produced through recombinant DNA technology
- these can be introduced to the body where they will elicit an immune response
Example of Recombinant Vaccines
1st vaccine for human use that was introduced using recombinant DNA technology was the HEPATITIS B vaccine, introduced in 1986.
It was produced by inserting a gene from the hepatitis B virus into the Cowpox virus
Most vaccines currently being investigated are focused on using recombinant bacterium ‘E.coli’ or cells from mammals, insects, or yeast to produce ANTIGENS.
Explain the process of creating the hepatitis B vaccine.
Produced using recombinant technology.
- The gene for a surface antigen on the virus is isolated and added to a plasmid.
- The plasmid is introduced into a yeast cell.
- When the yeast cell divides, the new cells also contain the plasmid with the gene for the antigen.
- This gene allows the yeast cells to produce the antigen protein, which can be collected and purified.
Explain how the HUMAN PAPILLOMA VIRUS vaccine is produced.
The HPV vaccine is produced via Recomb. DNA
- Produced in a similar way to hepatitis B.
1. USING RECOMBINANT YEAST OR INSECT CELLS
2. these cells produce PROTEINS that are found in the COAT OF THE VIRUS and are COLLECTED to be USED in the vaccine.
What are DNA VACCINES?
how do they work?
A vaccine stimulates an immune response by introducing antigen DNA which causes the host cells to produce the antigen.
- The DNA of the pathogen is incorporated into the Host’s cells, which will produce the antigen.
- The thought is that the antigen will then be expressed by the host cells, in a similar way to what happens during viral infections
Recombinant Vaccines VS. DNA vaccines
Recomb: antigen is produced and then introduced in the vaccine.
DNA: the DNA for the antigen is introduced in the vaccine instead of the antigen itself.
Disadvantages of Recomb. DNA vaccines
- Expensive - as the genes for the desired antigens must be located, cloned, and expressed efficiently in a new Vector.
IN ADDITION TO THE FINANCIAL DETERRENT TO INNOVATION -
- Those involved in vaccine research must be CONSERVATIVE
- vaccines are used on large numbers of healthy people, many of whom are children, THE SAFETY IS PARAMOUNT.
therefore, if a CONVENTIONAL VACCINE is known to be Safe, there is LITTLE INCENTIVE TO DEVELOP A NEW ONE USING GENETIC ENGINEERING.
Define Diabetes
DIABETES MELLITUS
- A group of diseases, all of which result in an abnormally high level of glucose in the blood and excretion of glucose in the urine
- HORMONAL PROBLEM that SERIOUSLY DISRUPTS HOMEOSTASIS.
- A person with Diabetes will have HYPERGLYCEMIA
- Type 1 diabetes and Type 2 diabetes
- Hormones INSULIN AND GLUCAGON usually keep the Blood glucose at the correct level for normal body functioning.
- THIS IS NOT POSSIBLE, HOWEVER, IN SOMEONE WITH DIABETES
What is Hyperglycemia
An abnormally high level of sugar in the blood; frequently found in people with diabetes
What is the main role of insulin?
What happens if there are insufficient amounts?
To lower the levels of glucose in the blood by stimulating cells to take in glucose, and by the liver and muscle cells converting glucose into glycogen.
If a person produced insufficient insulin, or if their cells are resistant to the effects of insulin, the amount of glucose in the blood remains high and they excrete large quantities in the urine.
What is Type 1 diabetes?
INSULIN-DEPENDENT DIABETES
- A form of diabetes that develops rapidly, usually before the age of 20; caused by the DECLINE IN INSULIN PRODUCING CELLS of the pancreas.
- TREATMENT = INSULIN INJECTION AT REGULAR INTERVALS
- genetic
AUTOIMMUNE DISEASE THAT DESTROYS THE BETA CELLS IN ISLETS OF LANGERHANS IN THE PANCREAS.
hence the body cannot produce insulin, and therefore blood glucose levels remain high after a meal
Explain the characteristics of Insulin-dependent diabetes
- Usually begins in childhood = used to be called JUVENILE DIABETES
- in AUS 10-15% of diabetes patients suffer from type 1
- Occurs because a fault in the patient’s immune system causes the DESTRUCTION OF BETA CELLS in the ISLETS OF LANGERHANS of the pancreas
- BETA CELLS PRODUCE INSULIN- therefore a person with type 1 diabetes DOES NOT PRODUCE INSULIN
- TREATMENT: in most cases, the person’s cells respond to insulin in the normal way, so the disease CAN BE MANAGED BY GIVING THE PERSON INSULIN
- Only treatment is REGULAR INJECTIONS of INSULIN or use the PROGRAMMABLE PUMP that provides a CONTINOUS SUPPLY of INSULIN UNDER THE SKIN - Insulin CANNOT BE TAKEN IN TABLET FORM because it is DIGESTED IN ALIMENTARY CANAL.
- Treatment DOES NOT CURE TYPE 1 DIABETES - they simply FULFIL A ROLE TO ENSURE THE BODY is ABLE TO FUNCTION.
- PATIENT MUST HAVE REGULAR INJECTIONS TO STAY ALIVE, but even with the injections of insulin, the LONG TERM EFFECTS ARE LIKELY TO BE KIDNEY FAILURE, HEART ATTACK, STROKE, AMPUTATIONS, BLINDNESS OR NERVE DAMAGE.
What is Type 2 diabetes?
ADULT ONSET DIABETES or NON-INSULIN DEPENDENT
- A common form of diabetes, that usually occurs in people over the age of 45 who are overweight; usually can be controlled via diet
Explain the characteristics of adult-onset diabetes
- usually develops in people over the age of 45; although increasing numbers younger people are now being diagnosed.
- Type 2 PATIENTS ARE ABLE TO PRODUCE INSULIN, BUT CELLS DO NOT RESPOND TO IT
- IS A LIFESTYLE DISEASE; more common in people who are not physically active and overweight or obese
- Incidence of T2D in AUS + other affluent countries is increasing rapidly due to the large number of people WHO DO NOT ADOPT A HEALTHY LIFESTYLE
- SO MANY AUS DIAGNOSED MAKING IT A HEALTH CRISIS
- estimated that 1/2 of AUS WHO HAVE TYPE 2 DIABETES ARE NOT YET DIAGNOSED - LIFESTYLE FACTORS THAT INCREASE THE RISK OF DEVELOPING T2D
- lack of physical activity
- being overweight or obese
- a diet that is regularly high in fat, sugar, salt, and low in fiber
- high blood pressure
- high blood cholesterol
- smoking - Develops gradually - no symptoms, or are not noticed
- Because the cells do not respond to insulin they do not take up glucose from the blood.
THEREFORE A BLOOD TEST TAKEN AFTER FASTING (not eating) WILL DETECT ABNORMALLY HIGH LEVELS OF GLUCOSE - NO CURE - but earlier diagnoses = give better chances of successful management of the condition.
- If UNDIAGNOSED OR UNTREATED, there is an increasing RISK OF COMPLICATIONS SUCH AS HEART DISEASE, STROKE, KIDNEY DISEASE, EYE PROBLEMS, NERVE DAMAGE AND SKIN, AND FOOT PROBLEMS.
- TREATMENT = management program that aims to keep blood glucose levels within the normal range
- includes careful diet, regular physical activity, maintaining a healthy weight, monitoring blood glucose, sometimes medications if blood glucose cannot be controlled by other measures - is PREVENTABLE
- chances of suffering from the disease can be reduced by adopting a healthy lifestyle
Explain the role of the thyroid, its effects and effects, and the 2 hormones it secerets.
- Thyroid gland located in the neck secretes 2 hormones:
T4 AND T3
- both have the same effect, but the most IMPORTANT FORM IS THYROXINE - T4 affects nearly every tissue in the body by stimulating carbohydrate, protein, and fat metabolisms
- Thus the SECRETION OF THYROXINE FROM THE THYROID GLAND REGULATES BASAL METABOLIC RATE
- Some of the energy released from chen=mical reactions stimulated by the thyroxine is in the FORM OF HEAT = IMPORTANT IN MAINTAINING BODY TEMPERATURE.
- Thyroid hormones are therefore also IMPORTANT IN LONG TERM HOMEOSTASIS IN BODY TEMEPERTRAURE BY THE GRADUAL CHANGE IN METABOLIC RATE THAT OCCURS FROM SUMMER TO WINTER.
- Secretion of thyroxine hormones is controlled by the thyroid-stimulating hormone (TSH)
- ANTERIOR LOBE OF THE PITUITARY GLAND, BUT ITS RELEASE IS CONTROLLED BY THE HYPOTHALAMUS IN THE BRAIN - AN EXCESS/DEFICIENCY IN THYROXINE CAN CAUSE DISORDERS.
It may be due to a problem in the THRYOID ITSELF, but in some cases, it can be due to IMBALANCE IN TSH.
EXAMPLES = HYPERTHYROIDISM ND HYPOTHYROIDISM
Thyroxine vs Tri-iodothyronine
T4 VS T3
T4 = a hormone secreted by the thyroid gland that regulates METABOLISM, GROWTH AND DEVELOPMENT
80%
Longer ‘shelf-life
T3 = a hormone secreted by the thyroid gland contains iodine and is the most powerful of the thyroid hormones; affects many body processes including TEMPERATURE, GROWTH AND HEART RATE
20%
‘3 iodines and shorter-shelf life’
What is Hyperthyroidism?
Overactivity of the thyroid gland resulting in abnormally high levels of thyroid hormones in the blood.
- TOO MUCH THYROXINE
SYMPTOMS = Because the cells are overstimulated, and the metabolic rate is increased, the symptoms of hyperthyroidism are RAPID HEARTBEAT, WEIGHTLOSS, INCREASED APPETITE, FATIGUE, SWEATING, ANXIETY.
what is GRAVES DISEASE?
A medical condition in which the overactivity of the thyroid gland results in the secretion of excessive amounts of thyroid hormones
- MOST COMMON TYPE OF HYPERTHYROIDISM
Explain the Characteristics of Graves disease
- Enlargement of the thyroid caused by an immune system reaction
- Not inherited, there does however seem to be a genetic predisposition for the condition.
- Symptoms in the case of GRAVES DISEASE = PROTRUDING EYEBALLS, KNOWN AS EXOPHTHALMIA
Explain how the treatment is used and what are the 3 methods?
- DURING THE PRODUCTION OF T4 and T3, IODINE IS ABSORBED from the bloodstream, concentrated in cells in the thyroid, and then incorporated into the molecules to produce the hormones.
- HENCE HYPERTHYROIDISM CAN BE TREATED with DRUGS THAT BLOCK THE THYROID GLAND’S USE OF IODINE.
- another method is to GIVE PATIENT a DRINK containing RADIOACTIVE IODINE.
- the radioactive iodine molecules are taken up by the thyroid cells, which are then killed via radioactivity.
- cells elsewhere in the body do not absorb iodine and are unaffected
- radioactive iodine is usually EXCRETED IN URINE EVENTUALLY - 3rd method is to use SURGERY to REMOVE SOME OR ALL OF THE GLAND
- less thyroid will be secreted as a result of less hormone being produced
WHAT IS HYPOTHYROIDISM?
Underactivity of the thyroid gland resulting in low levels of thyroid hormones in the blood.
- TOO LITTLE THYROXINE
MUCH MORE COMMON
- 6-10% IN AUS women
- smaller portion of men also affected
OCCURS when there are problems with PIT. GLAND, HYPOTHALAMUS, OR THYROID GLAND.
SYMPTOMS arise due to the DECREASE IN METABOLISM and may include
- SLOW HEART RATE, UNEXPLAINED WEIGHT GAIN, FATIGUE OR A FEELING OF LACK OF ENERGY, INTOLERANCE TO COLD, SWELLING OF THE FACE AND GOITRE
What are the causes of hypothyroidism? (Thyroid gland)
- thyroid gland problem is due to lack of iodine
- a thyroxine molecule contains 4 atoms of iodine (T4)
- a trio-iodothyronine molecule contains 3 atoms of iodine (T3)
THUS A DEFIEICNY of IODINE in the DIET can PREVENT the THYROID GLAND FROM PRODUCING ENOUGH HORMONES
- thyroid gland may become ENLARGED IN AN EFFORT TO INCREASE HORMONE PRODUCTION = GOITRE
—- Many people may suffer from iodine deficiency without being severe enough to produce visible swelling of the neck.
What is a GOITRE?
Swelling of the neck caused by an enlargement of the thyroid gland.
What has the Gov done to increase iodine in the diet?
in AUS 46% of people are affected,
- so iodine deficiency is now a PUBLIC HEALTH PROBLEM
- to try to ensure that people get sufficient iodine, the FEDERAL GOV. introduced COMPULSORY ADDITION of IODINE in most breads in October 2009.
- ALL BREADS, except organic bread and bread mixes for baking at home MUST NOW BE MADE WITH IODISED SALT
What may be OTHER causes for hypothyroidism?
Many people may suffer from iodine deficiency without being severe enough to produce visible swelling of the neck.
Although severe deficiency of iodine can cause hypothyroidism, the MOST COMMON CAUSE is an ATTACK ON THE THYROID GLAND BY PATIENT’S IMMUNE SYSTEM
CALLED HASHIMOTO’S DISEASE
OR SURGERY FOR CANCER OF THE THYROID THAT INVOLVES IN THE REMOVAL OF ALL, OR LARGE PART OF THE GLAND
Treatment for hypothyroidism
If the cause is LACK OF IODINE
- easily treated by the INCLUSION of EXTRA IODINE in the DIET
Treatment of other causes
- Tablets containing thyroid hormone are prescribed
NO CURE and the TABLETS must be taken for LIFE LONG
- DOSE of thyroid hormone must be carefully monitored because TOO LITTLE WILL NOT RELIEVE the symptoms, BUT TOO MUCH WILL RESULT IN HYPERTHYROIDISM
How were hypothyroid patients used to be treated?
with tablets made from the dried and powdered thyroid glands of animals, mainly pigs.
tablets contained both T3 AND T4 but not necessarily in the same proportions produced by the human thyroid.
they also contain traces of other hormones
Although these ‘natural’ tablets are still available, today most patients are treated with hormones made synthetically by a chemical process
SYNTHETIC THYROXINE MANUFACTURING
WHAT IS IT CALLED AND ITS SIGNIFICANCE?
WHEN IS IT PRESCRIBED?
WHAT IS CALLED IN AUS?
thyroxine was 1st ISOLATED in 1914
SYNTHESISED IN 1927
Levothyroxine is a manufactured form of thyroxine
- now is considered safe and effective that it is listed on the WHO LIST OF ESSENTIAL MEDCINCES
- AVAILABLE IN BOTH ORAL AND INJECTABLE FORMS under many different brand name
- in AUS it is sold as OROXINE, EUTROXSIG, ELTROXIN
- IT IS MOST COMMONLY PRESCRIBED DRUG FOR THYROID HORMONE REPLACEMENT
What is gene therapy?
The treatment of disease by replacing, manipulating, or supplementing nonfunctional genes in cells and tissues
- aims to treat or cure genetic abnormalities by identifying faulty genes and inserting healthy ones
- it is a way of using the genes themselves as the treatment
UNLIKE MOST CONVENTIONAL MEDICINES, WHICH TREAT THE SYMPTOMS OF A DISEASE, GENE THERAPY HAS THE POTENTIAL TO CORRECT THE UNDERLYING CAUSE.
What is the HUMAN GENOME PROJECT
A project with the aim of mapping the base pairs and identifying the genes in human DNA
- revealed the location of around 4000 potentially faulty genes
What is gene therapy doing now?
GENE THERAPY AND CELL REPLACEMENT THERAPIES ARE ALOS USED TO TREAT DISORDERS.
- gene therapy research is concentrating on SINGLE-GENE DISORDERS such as
CYSTIC FIBROSIS
HUNTINGTON’S DISEASE
MUSCULAR DYSTROPHY
SICKLE-CELLED ANAEMIA
- also investigating in CURING T1 DIABETES
When was it introduced?
SOME AREAS OF POSSIBILITY ARE?
First introduced in 1970
- still, only at the research level
SOME AREAS OF POSSIBILITY ARE
- REPLACING a mutated gene with a healthy copy
- FIXING OR INACTIVATING mutated genes
- INSERTING a new gene that will FIGHT the disease
- making the IMMUNE SYSTEM RECOGNISE DISEASED CELLS
What is the main concept of gene therapy?
A vector can be used to deliver desired DNA into a cell.
This DNA can be incorporated into the cell’s nucleus and undergo transcription and translation to produce the desired protein.
Diabetes gene therapy idea AND METHOD
Traditional treatment = focuses on introducing the insulin that the body cannot make.
GENE THERAPY - looking at methods of making it possible for the body to produce insulin again
One possibility = REPROGRAMMING OTHER CELLS TO PRODUCE INSULIN.
- gene for insulin is introduced into a vector
- the vector is then used to ‘infect’ the desired cells such as the ALPHAS cells of the IOL.
- these cells INCORPORATE the NEW DNA into their nucleus and are able to use PROTEIN SYNTHESIS TO PRODUCE INSULIN.
SIMPLY = T1D COULD POSSIBLY BE TREATED WITH GENE THERAPY BY USING VECTORS TO INTRODUCE THE GENE FOR INSULIN INTO ALPHA CELLS SO THAT THEY CAN PRODUCE THE HORMONE AND ALLOW THE BODY TO FUNCTION NORMALLY.
What is CYSTIC FIBROSIS?
A disorder controlled by 1 recessive allele carried on an autosome that is incurable but can be detected during foetal development;
- mucus-secreting glands; become fibrous and produce abnormally thick mucus, resulting in, among other things chest infections
Explain the characteristics of cystic fibrosis
WHAT IT AFFECTS AND HOW
- most common life-threatening genetic disorder among AUS of EUROPEAN DESCENT
- Mainly AFFECTS the LUNGS AND PANCREAS, but sometimes thE LIVER and REPRODUCTIVE ORGANS
- Characterised by THICK STICKY MUCUS SECRETED BY THE MUCOUS GLANDS.
- In the lungs, this mucus may clog the tiny air passages and trap bacteria, making a person with CF SUSCEPTIBLE TO INFECTION.
- Repeated infections and continual blockage of the airways may cause IRREVERSIBLE LUNG DAMAGE AND SHORTEN LIFE EXPECTANCY
- PANCREAS is also affected, PREVENTING SECRETION OF ENZYMES REQUIRED FOR DIGESTION.
- CF frequently promotes problems with NUTRITION AND NEED TO TAKE CARE WITH THEIR DIET.
CF causes, identification, DIAGNOSIS
- RESULTS when an individual inherits the recessive allele for the condition from each parent
- DIAGNOSIS
In most AUS states, a blood sample is usually taken from a baby’s heel within 2-3 days after birth
– If the blood test reveals that a child has the disease, a special low-fat, high-carbohydrate, and high-protein diet is advised. - the IDENTIFICATION of the CF transmembrane regulator (CFTR) gene in 1989
- was a step forward in developing a treatment for CF.
- MUTATIONS IN THIS SINGLE GENE RESULT in the disease, and Since its discovery, more than 900 mutations have been identified
- In 1991 scientists successfully corrected faulty CFTR genes in CULTURED CELLS by adding normal copies of the gene to the culture
- FIRST STEP TO GENE THERAPY for CF
Why was CF the logical choice to begin gene therapy on?
CF was the logical choice because
- It is a SINGLE-GENE DISORDER,
- the most severely affected ORGAN, the LUNG is relatively EASY TO ACCESS to provide treatment
- disease is SLOW TO PROGRESS, with the lungs of a NEWBORN BEING VIRTUALLY NORMAL, thus this would ENABLE GENE THERAPY TO BEGIN before damage to lung started to occur
Explain what happened during the first experimental gene therapy treatment…
WHEN WHO PROCESS EFFECTS ANYTHING NEW CONCERNED WITH?
The first experimental gene therapy TREATMENT BEGAN IN 1993, PATIENT WITH CF
- Researchers modified a common cold virus to act as the vector to carry normal genes to the CFTR cells in the airways of the lung.
- The first study was mainly CONCERNED with the SAFETY ISSUES OF THE TREATMENT
- Amount of gene transfer was probably too small to have a real therapeutic benefit and any benefit was short-lived
TRIALS OF ALTERNATIVE METHODS OF GENE TRANSFER ARE CONTINUING
What is Huntington’s disease?
An inherited disease that causes the death of brain cells and results in changes in mood, a lack of coordination, and an unsteady gait.
What are the characteristics of Huntington’s disease?
- Single-gene disorder, Hence researchers believed that gene therapy could be used to slow down/prevent its development
- Caused by MUTATION in a single gene on CHROMOSOME 4 called IT15
- CURRENTLY INCURABLE SELDOM GENETIC DISEASE
- SYMPTOMS APPEAR BEFORE THE AGE OF 40
- MUTATED FORM of a PROTEIN called HUNTINGTIN results in NERVE CELLS in the BRAIN being DAMAGES
- CAUSES PHYSICAL, MENTAL, AND EMOTIONAL CHANGES
- disease is characterized by OCCASIONAL, UNINTENTIONAL FLAILING MOVEMENTS of the ARMS and LEGS
DIFFICULTY IN MAKING VOLUNTARY MOVEMENTS
Person SUFFERS FROM PROGRESSIVE DEMENTIA,
AND LOSS OF ABILITY TO THINK CLEARLY
How is gene therapy for Huntington’s disease possible?
- CONDUCTED ON RATS AND PRIMATES
- POSITIVE RESULTS HAVE ENCOURAGED MOVEMENT TOWARDS A CLINICAL TRIAL ON HUMANS
What are stem cells?
STEM CELLS are
- UNDIFFERENTIATED CELLS that are CAPABLE OF REPEATED MIOTIC DIVISION for LONG PERIODS OF TIME, given the RIGHT CONDITIONS Can differentiate into SPECIALISED CELLS
What is Cell Replacement Therapy
The replacement of damaged cells with healthy ones.
ANY DISORDER, INVOLVING LOSS OF, INJURY TO NORMAL CELLS IS THE POTENTIAL TO THIS ‘CRT’.
USES HUMAN EMBRYONIC STEM CELLS
- CONTROVERSIAL AND ETHICAL QUESTIONS ARISE
CURRENTLY EXPLORING OTHER SOURCES OF CELLS TO HELP RESTORE PATIENT’S BRAIN FUNCTION.
Example of stem cell therapy.
CRT FOR NERVOUS SYSTEM generated the most interest due to DEBILITATING NATURE AND WIDESPREAD OCCURENCE OF NEURODEGENERATIVE DISORDERS
EG. PARKINSONS DISEASE AND ALZHEIMER’S
MOST ATTRACTIVE METHOD for RESTORING BRAIN FUNCTION IN PARKINSON’S DISEASE
- IS THE REPLACEMENT OF DYING NEURONS WITH HEALTHY NEURONAL TISSUE
pilot studies using embryonic stem cells have been carried out in humans with some success.
- THE TRANSPLANTED CELLS NOT ONLY SURVIVED BUT ALSO GREW AND ESTABLISHED CONNECTIONS WITH ADJACENT NEURONS.
USES HUMAN EMBRYONIC STEM CELLS
- CONTROVERSIAL AND ETHICAL QUESTIONS ARISE
CURRENTLY EXPLORING OTHER SOURCES OF CELLS TO HELP RESTORE PATIENT’S BRAIN FUNCTION.
What is tissue engineering?
OBJECTIVE?
used where?
The rebuilding of damaged tissues by the use of biology, medicine, and engineering.
The MAIN OBJECTIVE = Restore healthy tissues or organs for patients, thus ELIMINATES the NEED for TISSUE OR ORGAN IMPLANTS OR ARTIFICIAL IMPLANTS.
Being used to develop a wide range tissues such as BONE, SKIN, CARTILAGE AND ADIPOSE TISSUE
Why are stem cells INCREASINGLY used in Tissue engineering?
- Early research, used CELLS FROM INTENDED RECIPIENT, But in many cases, SUCH AS GENETIC DISEASE it was NOT PRACTICABLE
- In other cases the ORGAN from which cells were to be HARVESTED was DISEASED, so NOT ENOUGH NORMAL CELLS WERE PRESENT TO ENABLE A SUCCESSFUL CULTURE.
STEM CELLS OVERCOME BOTH PROBLEMS
Define Scaffold
A structure used in tissue engineering as a template for tissue growth.
What are the Characteristics of SCAFFOLD for Tissue engineering?
- NEED TO HAVE PORE SIZES that enable the CELLS TO GROW, while SIMULTANEOUSLY ALLOWING DIFFUSION OF NUTRIENTS THROUGHOUT WHOLE STRUCTURE.
- NEEDS TO BE BIODEGRADABLE
- so they can be absorbed by surrounding tissues without having to be surgically removed. - Can be SYNTHETIC AND NATURAL MATERIAL
Why are the scaffolding characteristics important?
Needs to be carefully established AS THE RATE AT WHICH THE SCAFFOLD DEGRADES NEEDS TO MATCH (as far as possible) THE RATE OF TISSUE FORMATION.
While the NEW CELLS are MANUFACTURING THEIR OWN MATRIX STRUCTURE AROUND THEMSELVES, the scaffold is PROVDIDNG A SUPPORT STRUCTURE that will eventually breakdown, LEAVING NEWLY FORMED TISSUE
Explain the Process of Tissue engineering using Scaffolds
- Requires an abundant supply of disease-free cells of specific types
- Once a Scaffold has been devised, suitable stem cells need to be cultured.
- Stem cells are seeded onto the scaffold, which enables further cell growth and proliferation.
- These CELLS ARE INDUCED to grow on the SCAFFOLD of natural or synthetic material, TO PRODUCE A 3D tissue.
- The cell-covered scaffold is implanted into the patient at the site where new tissue is required.
- As the new cells continue to grow and divide, the material making up the scaffold begins to degrade, or in some cases to be ABSORBED.
What is Alzheimer’s disease?
Alzheimer’s disease is a progressive form of dementia.
- Dementia is a broader term for conditions caused by brain injuries or diseases that negatively affect memory, thinking, and behavior. These changes interfere with daily living.
- A progressive disease that destroys memory and other important mental functions.
- Brain cell connections and the cells themselves degenerate and die, eventually destroying memory and other important mental functions.
- Memory loss and confusion are the main symptoms.
- No cure exists, but medication and management strategies may temporarily improve symptoms.
- 7 stages
- develops after 60
- not hereditary, can have high risk though
- Alzheimer’s disease is thought to be caused by the abnormal build-up of proteins in and around brain cells. One of the proteins involved is called amyloid, deposits of which form plaques around brain cells. The other protein is called tau, deposits of which form tangles within brain cells.
What is Parkinson’s disease?
Parkinson’s disease is a progressive nervous system disorder that affects movement.
- Symptoms start gradually, sometimes starting with a barely noticeable tremor in just one hand.
- Tremors are common, but the disorder also commonly causes stiffness or slowing of movement
- A disorder of the central nervous system that affects movement, often including tremors.
- Nerve cell damage in the brain causes dopamine levels to drop, leading to the symptoms of Parkinson’s.
Parkinson’s often starts with a tremor in one hand. - Other symptoms are slow movement, stiffness, and loss of balance.
- Medication can help control the symptoms of Parkinson’s.
- Parkinson’s disease is caused by a loss of nerve cells in the part of the brain called the substantia nigra. Nerve cells in this part of the brain are responsible for producing a chemical called dopamine.
Park and Alzheimer’s similarity
- memory loss
- commonly found in elderly people
- degeneration of brain tissue
- Caused by a deficiency of neurotransmitters (dopamine in Park, ACh in Alzheimer’s)
