However, that retrospective study has numerous study design limitations (i.e. it was nonrandomized, underpowered, and the different treatment groups were not comparable to each other).
IACUC approval requires consideration of numerous study design elements, including justification of the animal model, number of animals, procedures for animal care, and approaches to monitor and address pain and distress.
To avoid screening numerous studies designed qualitatively, methodology-related keywords were added to the search strategy.
However, having served on numerous study-design committees of such studies, I have to admit that the ideal study design is extremely difficult to find.
This has motivated numerous studies designed to investigate the survival capacity of this bacterium and its transmission routes in farm-animals and their environment [ 11].
Despite recognition of diabetes-specific quality of life as a useful patient reported outcome, as well as numerous studies designed to investigate the psychometric properties of the ADDQoL [ 11- 13], little work has been done to investigate the factors associated with diabetes-specific quality of life in large scale epidemiological studies.
The results of numerous studies designed to define conditions for the inactivation of PrPSc concluded that protein denaturants, such as sodium dodecyl sulfate (SDS) [ 13, 14], are effective in reducing infectivity, but that complete inactivation requires extremely intense conditions, such as 1 h of autoclaving at 134°C or treatment with 2 N NaOH or sodium hypochlorite for 1 h [ 12].
Numerous observational study designs exist, with the decision on which is most appropriate depending on a number of factors, including the exposure and outcome under investigation and knowledge of key methodological issues.
Since 1994 numerous studies were designed in our laboratory to determine whether aTf has a trophic effect on myelin production independent of iron.
