Biomedical Research Methods

When we look at biology to describe life processes and living organisms, we rely on chemistry to explain these processes in terms of ions and atoms. All biological processes including photosynthesis and digestion and chemical reactions involving changes in molecules made up of these atoms. All things are composed of atoms from less than 110 different elements. As scientists look for cues and cures to human and animal diseases, they must use a combination if interdependent, state of the art methods. Among these are: Chemical, mechanical, mathematical and computer simulations as they re useful in the preliminary stages of research where they can stimulate ideas about research directions In vitro tests are experiments performed in laboratory containers using tissues or cells. These are useful during the early stages of research to study the single effect of a substance in isolation (In vitro means in glass) Non-human animal models provide the most reliable and complete data on the functioning of a living system and an indication of how humans will react to a new drug or medical procedure Human studies involve taking laboratory data and effectiveness of new vaccines or medications and evaluating them in carefully staged clinical trials using informed human volunteers Epidemiological studies look at the occurrence and distribution of diseases in a population

Biomedical Research is increasingly incorporating chemical, mathematical, computer and mechanical methods to understand and simulate living systems. They are being applied in all levels of biological organization. They represent a simplified version of reality; they are helpful in understanding complicated biological principles

Chemical models

Analytical chemistry tests detect a substance or measure its potency and are useful in developing vaccines, prescription drugs and vitamins. Example: in an assay for botulism toxin (which normally requires up to 200 mice) antibodies obtained from the rabbits are modifies so the binding of the toxin can easily be detected. In 4 weeks, one mouse can produce enough antibodies to perform tests that would otherwise take thousands of mice.

Mathematical and computer models

Advances in computer technology have led to sophisticated mathematical models that can predict biological responses on the basis of a chemical’s structure and activity in an organism. Using this approach, the biological effects of chemicals can be quantified and correlated with a chemical’s biochemical properties, composition and structure. When a new or somewhat familiar compound is developed, it can be compared to the database of know compounds. This allows researchers to predict a new chemical’s likely biological properties.

Researchers are using this approach against HIV. Computer programs and structural information about the HIV’s key proteins are being used to design specific anti HIV compounds Strengths: Models increase the speed and efficiency with which data can be studied and processed. (the simpler the system being modeled, the more accurate the results). Also models provide the capability of extrapolating data from animals to humans As a result models may reduce the number of animals required in research) Limitations: They cannot replace laboratory testing and do not generate data. They only process what has been entered.

In Vitro Studies

They include an assortment of living systems, bacteria, cultured animal cells, fertilized chicken eggs or frog embryos. Scientists use cell cultures isolated tissues or organs in the early and intermediate stages of research. Many remedies are first tested in vitro to discover how they interact with human cells and tissues.

Example of in vitro studies: pregnancy tests—rabbits ere once injected with urine from a pregnant woman, then put to death in order to examine their ovaries which were used to determine if the woman was pregnant. IT WAS “GOOD NEWS” IF THE RABBIT DIED

Strengths: They allow scientists to study a single effect of a substance in isolation without the interference from other biological interferences such as enzymes, hormones and immune responses. They are also less expensive.

Cell cultures also contain cells that can replicate themselves in a liquid medium in a container. They are critical to the study of viruses which grow only in living cells. These viruses are weakened or atten_ _ _ _ _ to provide the killed or weakened virus needed for vaccines

Limitations: The chemical process leading from chemical exposure to toxic effect cannot be duplicated in vitro. Cells do not metabolize toxins in culture the same way they do in the body. It is difficult to maintain differentiated cells in culture since the cells tend to become unspecialized after a short time losing the characteristics of the organ from which they were taken so cells can’t generate sufficient reliable data Non-human animal models

For ethical reasons it may not be feasible to conduct experiments on humans. Instead animal models are used. Animals provide the best known surrogate for humans

By combining what they know about the differences with knowledge of our biological similarities, scientists can apply results from animal experiments to the human condition

Animals are vital because they provide a whole c complex living system that can interact and react and react to stimuli like humans

Strengths: Animal models provide an ethical alternative to the use of humans in experimental studies. Because they share the same structures ( cells, tissues, organs and systems)

Limitations: because animals are not identical to humans, the results from experimental animal studies must be extrapolated to humans