DEMO DEMOChanges in Certain Parameters
Heart rate can go up or down or show several different changes during the course of a drug effect. Cardiac rhythm may alter, i.e. the beat become irregular with or without the average rate changing. Systolic, diastolic and mean pressure may change independently and pulse pressure may also change.
Changes may take place from different base-lines and it may be important to know BOTH the size of the change AND the value at the start. Changes may also have a different latency or a different duration; don't just concentrate on the size of the response.
Appreciate that heart rate and blood pressure may show small spontaneous changes unrelated to the effects of administered drugs. The significance of a change is important; not the statistical significance (which would need repeated determination to be estimated) but the significance in relation to the size of the change measured and the stability of the system. Thus a change of 2 mmHg in the 50 mmHg response to a pressor agent should be noted but may not be important.
Accuracy
Measurements must be accurate bearing in mind:
i) the purpose for which the measurement is made.
e.g. If you are trying to find ' which drug is more potent ' and there is at least a ten-fold difference then a crude measurement is all that is necessary. If the question is 'how much more potent' then a more accurate measurement may be required.
ii) the system on which the measurement is made.
e.g. On a chart recorder calibrated 0-200 mmHg on a 10 cm chart there is no point in trying to measure to 0.01mmHg. The system is simply not discriminating enough.
Report Writing
1) Structure
A report PRESENTS in words the data obtained, their meaning and deviations from the expected results. This presentation is supported by data. The text MUST lead the reader through the presented data, your reasoning, a discussion and conclusions. It is NOT adequate to simply present a pile of data and the conclusions, leaving the reader to join the two parts up.
2) Presentation
Set out your report clearly. Use headings (title; introduction; methods; results; calculations; discussion; conclusions; references).
3) Be concise
Don't over-elaborate and confine the report to what is asked for.
4) Be consistent
Always use the same abbreviations. A set of rules helps and an excellent set are those provided by the British Journal of Pharmacology and detailed in, for example, Br. J. Pharmac., 114, 245-255 (1995).
5) Take care with detail
A sloppy report suggests that the writer is disorganised and hurried and can't be bothered to take the time and trouble to do a good job. The implication is that the experiments were probably done with the same attitude and that the data is not to be trusted.
6) Be neat and tidy
This is particularly important when presenting graphs and tables. Data presented carefully and neatly was probably gathered with the same attitude and is reliable.
7) Remember the scientific method
Scientific Method:
hypothesis >>>> prediction >>>> assemble experimental data to test prediction >>>> confirm, modify or reject hypothesis.