Question

Endocrinology Fifth Assignment (Practical) Q1: A:What are ethical issues that should be taken in consideration in using animals in research and teaching? And what are the main characteristics of these animals? B: Determine the sources of errors (experimenter and instrumental) in doing ELISA? C: The following figure represents the response of four subjects to oral glucose tolerance test (A, B, C, and D), interpret the results for each case and if is not normal, what will be the cause and the treatment? Oral Glucose Tolerance Test (OGTT) A

Answer 1

Solution:

A) Ethical issue in using animal in research and teaching:

There are some ethical issues that should be considered while using an animal for experimentation. Before experiments on animals are conducted, the research protocol must be reviewed by animal ethics committees. The guiding principle of these committees is usually the 3 R's.

1. Animal experiments must be replaced wherever possible by other methods such as mathematical modeling, or an in vitro biological system.
2. There must be a reduction in the number of animals used. Only the number required to obtain reliable data must be used in an experiment. A thorough literature search must be done beforehand to prevent duplicating experiments.
3. Third, the study must be refined to minimize its overall impact on the animals used.

There should also be a local animal care committee in order to ensure that the animals are housed in appropriate facilities. The committee should also determine if the animals are needed to test the hypotheses listed as well. If so, the animal care committee should also determine the appropriate sample sizes and procedures that are to be used in the experiment. The animals should have access to veterinary care in deed. All personnel who work with the animals should be sufficiently trained in both the experimental procedure and ethical handling of the animals.

The importance of research ethics is what drives how these animals should be treated. That includes having a clear reason for why a hypothesis needs to be tested using animals. Also, there should be a reasonable expectation that the experiment will generate useful data. The study design should also seek to minimize the number of animals used in the experiment while still being statistically appropriate.

The characteristics of animals used in laborotory reasearch are as follows:

1. The animal model must have similar physiology and anatomy to humans.
2. Animals can be fed identical and we can closely monitor their diets. As with inbred mice, members of some animal species are genetically identical, enabling researchers to compare different procedures on identical animals.
3. Their life cycle is short and the gestation period is less compared to humans.
4. Ease of availability is also one of their characteristics.
5. The therapeutic target must be naturally present in the animal model.

B) Sources of errors in ELISA:

Some of the sources of errors that happen during ELISA are as follows:

1. Out of Range: Sometimes this can happen based on your samples(Samples contain no or below detectable levels of analyte), insufficient washing or incorrect dilution prepared, buffers contaminated with metals or HRP. This can result in a loss of data due to negative or no results.
2. High Variation: High variation can be due to sample preparation mistakes( Samples may have high particular matter), pipette errors and inconsistencies, insufficient plate agitation, crosswell contamination among other problems. Data with high variation can skew the real results and cause inconsistencies in your data.
3. Background is high: High background may result from inadequate washing steps, cross reactivity of samples or contamination. Again high background may result in false positive/negative data and affect your results.
4. No Signal: No signal in your ELISA assay may result from numerous sample and assay problems including wash buffer contains azide, target below detection of assay or avidin-HRP was not added. No signal may mean no results from precious samples, have a read through the reasons below to avoid these problems.
5. Poor Standard Curve: A poor standard curve will prove unpublishable results if not prepared correctly. Reasons may included reagents are poorly mixed, the standard has degraded or pipetting errors.
6. If longer incubation than needed is done, then it can lead to various errors.
7. The dilutions of antibody/reagents are poorly mixed.

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