The independent variable is the lipopolysaccharide (LPS) because it is the variable that is changed among the groups. The dependent variable would be the amount of inflammotin discovered in the elderly because this variable would change with respect to LPS. For purposes of mathematical modelling this relation could also be interpreted as the amount of inflammotin being a function of LPS.
Experimental Design
Groups
In this experiment there will be 3 groups, one who will take 6mg of LPS, another 8mg, and the other no LPS. The group without LPS is the control group.
Number of subjects per group
Each group will have 8 subjects, totaling to 24 subjects for the experiment. Also, each group will have 4 females and 4 males.
Before the experiment, blood samples will be taken and analyzed from each group. Blood samples will be analyzed from our subjects using ELISA. All three groups will be tested at the same time. Time will be allowed for the LPS to affect the amount of inflammotin synthesized. Afterwards, another set of blood samples will be taken. The experiment will take place thrice. If it is found that the group who takes 6 mg of LPS has increased inflammotin levels then another three trials will be run with 5 and 4 mg groups in order to further determine a minimum level needed for effect. If instead the 8mg group is affected but not the 6mg group then a group will be tested using 9 mg in order to further narrow down the interval which contains the minimum amount of LPS needed to stimulate increased inflammotin levels. Further trials will be run on the rule of determining a narrower minimum interval in which the amount of LPS still affects inflammotin levels with the lowest determined level serving as an closed upper bound for every new set of trials. If and after below 6mg require testing then the new testing groups will only be apart by 1 mg in the amount of LPS taken in order to be able to more accurately determine a mimimum amount. At the end of these trials a small interval of 1 mg or less should be determined.
Subject Selection
The subjects should be between the ages 65 to 79 years as we are trying to see the effects of LPS on the elderly. Half of our subjects should be females, the other half males, so that we can control for any difference between genders, if one exists. They must not have any inflammation anywhere prior to the experiment. Subjects must be willing to fast for 12 hours prior to the blood test.
Sources of Error and Bias
(What are some of the potential sources of error or biases that could affect your results and how would you control for them?)
Differences in exercise, diet, environment or metabolism could affect the digestion of the pill, as it could have already fully digested or haven't finished digesting by the time blood samples are tested. To control these and other extraneous variables, subjects will be assigned to equally-sized groups based on a block randomization model. Fasting will also help lessen error caused by differences in diet. Also, the patient's own unique body would be an unavoidable source of error simply because every patient tends to react just a bit different when given the same treatment.
BME 100 Fall 2013
