Reduction & Replacement

Question 1

Two main types of tissue cultures

Answer 1

• organotypic cultures - parts of a tissue or organ placed in culture medium (3d structure limits access to nutrients and removal of waste, resulting in decreased durability)
• cell cultures ( typically results in loss of morphological and biochemical properties of cells and progressive divergence from the original cell type; commonly used for vaccine production, e.g. poliomyelitis vaccine produced form kidney cells

Question 2

Pros of in vitro studies

Answer 2

• generally more sensitive than in vivo studies since the isolated cells and organs receive no input form other body parts + models grown under well-controlled conditions
• no need for anesthesia (which might interfere)
• interpretation may be easier (although extrapolation is more problematic)

Question 3

Use of lower species

Answer 3

• bacteria, fungi, insects, mulluscs, plants…
• e.g. use of bacteria in Ames test to screen new compounds for mutagenic properties (carcinogenesis)
• yeast is used on a large scale as a vector for the expression of specific genes coding for antibody fragments or vaccine antigens
• by transgenesis, plants can also be made suitable for vaccine production

Question 4

Some examples of in vitro & other techniques for replacement

Answer 4

• HPLC (high pressure liquid chromatography) - most naturally derived hormones are now produced by rDNA techniques resulting in purer products. HPLC is being used for potency testing of these hormone preparations.
• physiologically based pharmacokinetic modelling can make predictions of the absorption, distribution, metabolism and excretion of drugs
• human tissues, blood, etc.
• replacement of the rabbit eye irritation test by using bovine or chicken eyes from slaughterhouses

Question 5

Classical fallacies in (ethical) argumentation with respect to relevance

Answer 5

• appeal to the public
• argumentum ad hominem
• unwarranted appeal to compassion (sentimental)
• argument from authority
• appeal to involvement (someone suffering from heart disease in your family)

Question 6

Logical fallacies in (ethical) argumentation:

Answer 6

• argument from ignorance (no evidence of pain in cows, means no pain in cows)
• circular argument (begging the question)
• argument from correspondence (logically false analogies)
• unwarranted generalization (not all animal research yields useful results…therefore no point)
• a priori reasoning (accident; health is good, gene therapy improves health, ergo gene therapy is good)
• post hoc ergo propter hoc (sequence is confused with consequence)
• naturalistic fallacy (is/ought) (use of animals fits into the normal order of nature)
• on not being consequent (against animal experimentation and still accepting medicine for sick child
• equivocation (ambiguous terms and concepts