Lesson A3 - DOSE-RESPONSE CURVES AND SELECTIVE TOXICITY Flashcards
__________ refers to the amount of drug that must be given to obtain a particular response.
Potency
If drug A is more potent then drug B then a user need to take __________ of Drug ____to get the same effects as drug ___
Less, A, B
___________ Is the maximum effect that is obtainable with a given drug
Efficacy
Morphine had a greater _________ than aspirin in the relief of pain
Efficacy ( Morphine can relieve more intense pain than aspirin can)
What is more important? Potency or Efficacy?
Efficacy (Because no matter how potent a drug is ……. If the efficacy of the other drug is greater you will be able to achieve higher maximum results)
On a dose response curve the x -axis ( horizontal axis) measures the __________ of a drug
Potency
On a dose response curve the y -axis ( Vertical axis) measures the __________ of a drug
Efficacy
A pesticide used for killing insects is know as an _____________
Insecticide
A pesticide used for killing plant life is know as an _____________
Herbicide
_______________ means the injury of one type of living matter without harming some other kind
Selective Toxicity
There is a widespread need for agents, knows as ___________, that will kill fungi, weeds, and insects pests without harming plant growth
Pesticides
Explain a case of selective toxicity
10% Sulphuric Acid –> It it toxic to weeds but not to cereal grass. Weeds exterior is rough and wax free so it can accumulate but the exterior of cereal grass is smooth and waxy so the Sulphuric Acid runs off
In order to treat cancer a combination of _______________ are often used
Anticancer drugs
What are two mulitdrug resistance proteins that have been found in cancer treatment
P-glycoprotein, the mulitdrug resistance protein (MRP)
Some cancer cells which are resistant to the action of these drugs have been found to have a mechanism for ____________ these ______________
extruding, Anticancer
Two drugs that have a normal function in the body , but if overproduced by a tumour, can result in drug resistance
P-glycoprotein, the mulitdrug resistance protein (MRP)
Chemotherapy is an example of _______________
Selective toxcitiy
Early theories of disease suggested the body was overcome by _____________ and the most efficacious treatment was to get rid of these spirits from the body
Evil spirits
List 3 ways that people tried to rid the body from evil spirits
- Sulphur burnt to create bad fumes and drive evil spirits away
- Blood letting
- Administer agents promoting urination
The demonstration that diseases of many types are caused by __________ was made by _________ in the ____ century
Microbes, Pasteur and Koch, 19th
What demonstration caused people to attack disease on a rational basis
The demonstration was to show that diseases of many types are caused by microbes
During the latter part of the 19th century, most scientific workers believed that there was little hope of finding a cure for ____________________
Microbial diseases
What did people believe about substances that killed microbes?
That these substances would also kill the individual whose body the bacteria were living
What pessimistic view did Paul Ehrlich not share with other scientist and who is Paul Ehrlich?
- He didn’t believe that any substance that killed microbes had to also kill the individual whose body the bacteria were living
What did Paul Ehrlich also observe regarding dyes?
Some dyes stained certain body tissues and not others
The dye methylene blue stained ______________(3 words)_________
Preferably
What did Paul Ehrlich reason?
That he should be able to design chemicals that would specifically stain parasites
Paul Ehrlich realized that the staining of the parasite would be ____________ to the strong binding of chemical to the parasite
Equivalent
Paul Ehrlch reasoned that if he could attach a _______________ to the chemical he would be able to design a substance that would __________4 words_______________________
toxic grouping, specifically kill the parasite
Paul Ehrlich reasoned that the specifically-designed chemical would bind only to the __________ and not the ___________
Parasite, Human cells
Who said the following quote?
“In this way, we arrive in an natural manner to this: that chemotherapeutic agents built up in a complicated manner may be compared to a poisoned arrow. The fixing group of the drug which anchors to the chemoreceptor of the parasite, corresponds to the point of the arrow. The binding member is the shaft and the poison group is the arrow poison fixed to the shaft of the arrow.”
Paul Ehrlich
Paul Ehrlich said the proposition “ Corpora non agunt nisi fixata which means “ bodies do not act unless fixed”. What did he mean by this?
By this he meant that a drug would not act on a parasite unless it was attached to it first.
The idea of a drug would not act on a parasite unless it was attached to it first was not believed by many scientists. How did the scientists think drugs worked in this time?
At the time, it was believed that drugs acted by stimulating the body’s defence system.
The drug Atoxyl was active in a test tube but not in a person’s body. True or false?
False, It was active in a person’s body but not a test tube and therefore people believed that this drug worked by stimulating the body’s defence system.
What was Ehrlich able to show about how Atoxyl worked in the body
Ehrlich was able to show that Atoxyl is converted in the body to an active form which then attaches to the parasite.
Ehrlich utilized _______ as his toxic grouping and synthesized many derivatives of this compound.
arsenic
What was Ehrlich arsenic compound used to treat and where was it tested
Syphilis, Rabbits
How many compounds did Ehrlich test before he found one that could kill the syphilis organism in rabitts and was safe to use in humans
606th
True or False! At the beginning of the 20th
century, most hospital beds in London were occupied by patients with syphilis. By 1920, several years after the introduction of Salvarsan, such patients were rarely seen on the wards. Instead they were treated on an out-patient basis in special clinics.
True –> Paul Ehrlich used his arsenic based compound
What were the 4 requirements that Ehrlich said were necessary for success in scientific research?
(1) Geld (money); (2) Geduld (patience); (3) Geschick (cleverness); (4) Gluck (luck).
In 1935 Domagk, working at the Bayer factory in Germany, Studied the effects of a large number of chemical compounds against a bacterium know as ___________ in mice
Streptococcus
What drug did Domagk discover that was able to harm the streptococcus without harming the mouse.
Prontosil
Between the years 1932-1935, _________ of patients having streptococcus in their blood died.However, after 1935 with the introduction of ___________, very few patients died from this cause.
71%, Prontosil
Prontosil was found to be __________ against the streptococcus in the test tube.
Inactive
Why was Prontosil found to be inactive in the test tube?
Because Prontosil is split in the liver to give sulfanilamide which is the active principle
Prontosil was found to be inactive in the test tube because Prontosil is ________________________ to give _____________ which is the ________ Principle
split in the liver, sulfanilamide, active
Why is sulfanilamide selectively toxic?
Because both microbes and the host cells require a substance called “Folic Acid” for growth. Folic acid is available in the body and crosses into the host’s cells which are then able to use the folic acid. Folic acid is, however, unable to enter microbes.
What does PABA stand for?
para-aminobenzoic acid
Sulfanilamide closely resemble _____________ in structure
PABA
___________ closely resemble PABA in structure
Sulfanilamide
What is the analogy regarding PABA and sulfanilamide
PABA can be considered the key for the lock. Sulfanilamide closely resembles the key, gets into the lock and blocks the lokc so that PABA (The key) cannot get into and open the lock
How do microbes continue to grow if they can’t make folic acid?
They take up PABA –> Which is then used to make Folic acid
The microbe cannot distinguish between ____________ and _______ and is __________ into trying to use ________________ instead of _______
Sulfanilamide, PABA, fooled, Sulfanilamide, PABA
Sulfanilamide are referred to as ____________
Antimetabolites
What are Antimetabolites?
They act against substances required for the metabolism of an organism
Since the host cell uses ________________________, it does not require ______ and is therefore not affected by the PABA antagonist, _____________
Preformed folic acid, PABA Sulfanilamide
“It was thought that if differences could be found, then chemicals could be designed to interfere with a reaction going on specifically in the microbe.” Studies of this type led to the the development of several drugs for the treatment of what diseases?
Viral diseases including the HIV virus
