B6.3b Flashcards
How does a scab form and why is it necessary
1) protect against pathogens and stop bleeding out
Platelets are sensitive to oxygen, in the presence of this in a cut they:
- PLAYELETS change blood protein fibrinogen into fibrin , forming a network of Forbes in the cut. This is solid now.
2) here red blood cells are also trapped in the fibres. Forms the clot
3) over time clot hardens to form a scab, keeping skin clean and allowing it to heal. Once heralded it will fall off
What are the other non specific defences that body has?
Skin Cillia mucus HCL Eyes Nasal hair
Skin- Physical Barrier, in which the dead outer cells make it hard for pathogens to penetrate. Also produce antimicrobial substances by sweat glands that kill pathogens
Acid in stomach- HCL here kills pathogens in food
Cillis and mucus in airways
- respiratory tract lined with these that trap particles and waft back up to be swallowed
Eyes
- in tears prüfe enzyme lysozyme which break down bacteria on surface of eye
Nasal hairs= keep outs dust and large microorganisms
And skin…
Now what about how immune system attacks pathogens?
White blood cells in two types, how does phagocytosis work
PHAGOCYTES: engulf pathogens and make enzymes that digest them, called phagocytosis
LYMPHOCYTES: these make antitoxins and antibodies that attack pathogens alike
What are antigens
Molecules on pathogens
How do lymphocytes producing antibodies and antitoxins work?
What happens after they are killed?
What about antitoxins
When forgone antigens are detected, they will produce antibodies, proteins that are SPECIFIC to an antigen, and this takes some time to do as it is specific response.
- these are rapidly produced and cause antigens to group together making it easier for phagocytes to attack them in phagocytosis . They also Directly KILL THEM TOO
2) after they are killed, memory cells remmeber the antibody produced and stored a template for later on .Now if the same pathogen comes again, the lymphocytes will rapidly produce them and kill the, before they can cause illness- immunity .
3) they also produce antitoxins to counteract toxins by bacteria
What are monoclonal antibodies?
They are produced as clones from a single cell, therefore monoclonal. They can be used to target a specific chemical or cell.
How are they made (monoclonal) 6 marker?
1) first a Moshe is injected with an antigen (in a hormone/pathogen)
2) mouse immune system in next week will work on producing antibody this fits the antigen required. These will be found in the mouse’s B LYMPHOCYTES WHICH ARE EXTRACTED
3) As these can not divide easily and survive outside the body to produce more, they are fused with a MYELOMA. These are tumour cancerous cells which divide indefinitely. This fusion produces a hybrid : a hybridoma
4) these hybridomas clone as they divide indefinitely giving clones of the antibody , which are then harvested. And then purified
5) now can be used for things…
What ca no Nikon always antibodies be used form
Pregnancy testing
Detecting disease
Treating cancer
How do monoclonal antibodies used for detecting diseases
Why is this useful
The mocnoclonal antibdoies in the body act as markers. Here they bind to the prostrate gand cancer cell antigens for example and confirm its presence as they show a bright spot. Now under specific cameras the exact location of cancer cells are shown…
Good as it allows. For early diagnosis and higher chance of survival
How are mABs used for detecting pregnancy?
1) woman pregnant= human chronoic gonadotropin (hCG) is priced after TWO WEEKS OF CONCEPTION.
2) monoclonal antibodies have been produced that will bind to the antigens of this hCG protein causing a chemical COLUR CHANGE
3) when a woman urinated on the stick containing hCG monoclonal antibodies, colour change will take place auch that a line appears, confirming pregnancy
Man used in measuring and monitoring in sport and gps?
Used in sport to see if illegal drugs been used
GPS can use them to monitor hormone levels
How used to treat cancer mab?
What cancers are they used in
1) anti cancerb drugs can be attached attached to the monoclonal antibodies, and carry straight to the cancer cell avoiding healthy, these involve radioactive unsatnces , MORE EFFECTIVE
2) CAN also kill them or preventing them from receiving growth hormone and getting bigger
Used in breast stomach Bowel cancers…
Advantages disadvantages of monoclonal antibodies.
Why better than. Other cancer treatments
What are considerations
Mouse
1) initlslh known as magic bullets due to specificity. Here they can target cells without hurting others, favourable other radiotherapy for instance . Meaning hair won’t fall off, or nausea induced by radiotherapy…
2) being specific means extremely expensive
- difficult to attach chemicals to antibodies
- side effects there, due to them being developed by mice … and d inference of lymphocytes…
Unethical to use mouse too…
How do vaccines work and what do they contain
Vaccines contain small amounts of weakened or dead versions of a pathogen
- these carry a tigers, so even though harmless will still trigger and immune response
- memory cells will keep antibodies that had to be specifically produced against these pathogens, and they
Rosy does immediately - now when you catch the pathogens they will be destroyed even before they have a chance to make you sick. Your ar now immune
How do white blood cells detect foreign substances.
Antigens are kn al cells in body, so white blood cells recognise. As soon as foreign antigen comes, ropes. This is why cancer cells aren’t removed, as produced by own body…
What is herd immunity
What can end it
When majority of population gain immunity so that the chance of actually Sharon a patjpheb is reduced…
Yet if people, stop, then resirgence of old diseases can return
What are antibiotics?
What is example of superbug and why
How do they accomplish this
Therefore why not work on virus
How do antibiotics prescribed
What is the relationship between zone of inhibitor and effectivenss of antibiotics
Who developed penicillin the first antibiotic
Drugs that kill bacteria without damaging your own cells, but no effect in other pathogens like viruses or fungi
- naturally produced and grown on large scale
- naturally resistant to some, but over subscribing and not finishing g treatments lead to some resits t strains of bacteria, such as MRSA superbug
Damage the cell walls
4) virus don’t have cell walls
5) swab taken and bacteria grown and then tested with antibiotics and seen with zone of inhibitions
Larger inhibitions read the better
6) Alexander Fleming
What are antiseptics
Who is godfather
Common examples
How are they different to disentfectants!!
Antiseptics: Chemicals that kill are netirilse pathogens without damaging HUMAN tissue MISLRY USED FIR preventing OF INFECTION NOT TREAT IT
2) Joseph listed with carbolic acid
3) alcohol and iodine
DIsinfectants are for NON LIVING SURFACES!!!
What are antivirals
Are they specific or no
What do they do if not kill them, and why not kill?
Are drugs that destroy viruses mostly from stopping them in their conduct
They are specific on viruses
- blocks viruses from entering host cells
- prevents them releasing their genetic material
- or let’s them release but not insert into shot cell genome
Now once they can’t replicate eventually they die
Hard to kill as they take over host cell, end up killing host cell too..
Summary of these medicines?
Antibiotic bacteria in body
Antiseptics bacteria on surfaces of body like wounds
Antivirals for viruses
Disinfectants for dead surfaces non living
What is aseptic technique
Working without microorganisms, preventing foreign microorganisms from being introduced into test samples that potentially can cause CONTAMINATION that can affect results…
What ways can you work aspetically and hw do they work?
Sterile Ppe Bunsen flame Waft neck AUTOCLAVE
- disinfect all surfaces and equipment regularly with alcohol before and after working
- to ensure no microorganisms are there in area
2) sterilise equipment and glassware before and after using autoclave (steam high pressure). Even agar jelly
- unwanted contamination prevented
3) pass loop in flame inoculating this kills and sterilise
4) work close to a Bunsen flame
- hot air rises so in the air will be drawn away fr, the culture
5) flame neck of glass bacteria before and after opening
- causes air to move out f container causing unwanted dons from coming in.
6) wear gloves and necessary ppe
What about doing the Inder ich bacteria practical, how can you work aspetically and safely here
1) do not seal all the way round as pathogens thrive in anaerobic conditions
2) don’t open plates
3) incubate at 25°, so harmful pathogens won’t grow at this temp
4) keel plate upside down after streaking , means airborne particles won’t be able to fall on them
5) keep as short distances as possible, only open as little as possiboem
Finally how to briefly grow bacteria
What happens if different colour spot?
1) autoclave everything
2) now sterilise inoculating loop and streak the thing. 4 or 5 times
Sterilise and reltstse do it again
Her make a second series of streaks by crossing over the first set, picking dome of the cells and putting them in other section
Do this again for a third
Clos the lid and incubate upside down for dwysbletting them grow
If one spots then only one colony and
worked aspetically other coloured mean contamination…
What is looked for when developing drugs?
If it is safe (side ffects)
If it is effective (actually treat the symptoms and how good )
Stable (ability to be stored under normal conditions )
Successfully taken into and out of human body( reach its target, safely removed by excretion?)
So how are pre clinical trials carried out?
3
1) scientists used computer modelling to simulate a humans responsible ein a drug , and then identify promising potentials
2) next they perform lab tests kn human tissues, so cells , bacteria and tissue cultures. This bit is still pre clinical. MOST DRUGS FAIL ST THIS TSAGE BECAUSE THEY DAMAGE CELLS OR NOT WORK
3) next if passes this it goes to testing in animals. Law in U.K. is it has to pass two species of anaimls. (Some people say it cruel but shush )
How are the actual clinical trials carried out?
4
1) next tested on small group of healthy volunteers to look for any random SIDE EFFECTS when body is working normally. (Sick People could feel effects if it goes wrong, so not done on them at this point ). Basically down to see if SAFE !!!
2) then it is done on a small amount of volunteers with the ILLNESS, to see how effective the drug initially is
3) then it is done a larger number of people , few thousand, with the illness, to se show well it works and safe dir everyone
4) if pass all tests, approved by mars and can be prescribed but still knotend and looked for
When the first trials given to humans with the disease, what is done to ensure placebo effect is not happening
Placebo is when people, think they have medicine so ohsycoogicslly feel better but this isn’t rekted to symptoms
What should the company do as well?
Two grotto groups are given drug or placebo.
Here neither the doctor or patients know what is being given until the test is over, so no bias is ensured into the patient and placebo effect is negated, snd also no bias in doctor when collecting data. This is called a DOUBLE BLIND ?
Now you can actually see who feels better and effectiveness of drugs and not as a result of placebo effect…
However some trials where everyone ill it isn’t happened because unfair to negate of poetical treat,ent
2) give it to another company and carry same trials without paying them so lying doesn’t happen
