In-Vivo Preclinical Trial
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An In-Vivo Preclinical Trial is a Preclinical Trial that is based on in-vivo testing that involves other living organisms than humans to predict clinical endpoints.
- Example(s):
- Counter-Example(s):
- See: Clinical Trial, Randomized Comparative Experiment, In-Vitro Experiment.
References
2022
- (Wikipedia, 2022) ⇒ https://en.wikipedia.org/wiki/In_vivo Retrieved:2022-1-15.
- Studies that are in vivo (Latin for "within the living"; often not italicized in English ) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and plants, as opposed to a tissue extract or dead organism. This is not to be confused with experiments done in vitro ("within the glass"), i.e., in a laboratory environment using test tubes, Petri dishes, etc. Examples of investigations in vivo include: the pathogenesis of disease by comparing the effects of bacterial infection with the effects of purified bacterial toxins; the development of non-antibiotics, antiviral drugs, and new drugs generally; and new surgical procedures. Consequently, animal testing and clinical trials are major elements of in vivo research. In vivo testing is often employed over in vitro because it is better suited for observing the overall effects of an experiment on a living subject. In drug discovery, for example, verification of efficacy in vivo is crucial, because in vitro assays can sometimes yield misleading results with drug candidate molecules that are irrelevant in vivo (e.g., because such molecules cannot reach their site of in vivo action, for example as a result of rapid catabolism in the liver). The English microbiologist Professor Harry Smith and his colleagues in the mid-1950s found that sterile filtrates of serum from animals infected with Bacillus anthracis were lethal for other animals, whereas extracts of culture fluid from the same organism grown in vitro were not. This discovery of anthrax toxin through the use of in vivo experiments had a major impact on studies of the pathogenesis of infectious disease. The maxim in vivo veritas ("in a living thing [there is] truth") Life Science Technologies, Cell Signaling: In Vivo Veritas, Science Magazine, 2007 is used to describe this type of testing and is a play on in vino veritas, ("in wine [there is] truth"), a well-known proverb.
2016
- (Grant, 2016) ⇒ William B. Grant (2016). "The role of geographical ecological studies in identifying diseases linked to UVB exposure and/or vitamin D". In: Dermato Endocrinology 8(1):e1137400. DOI:10.1080/19381980.2015.1137400.
- QUOTE: Four methods exist to determine whether UVB exposure and vitamin D affect disease outcomes: ecological studies, observational studies, laboratory studies, and clinical trials.
- Ecological studies can be of 2 types:
- Geographical. Health outcomes and risk-modifying factors are averaged for populations divided along geographical lines.
- Temporal. Health outcomes are examined for seasonal variations or trends.
- Observational studies come in several forms:
- Case–control. Risk-modifying factors measured at the time of disease diagnosis.
- Cohort and nested case–control. Subjects are enrolled in a study, risk-modifying factors are assessed, and then the cohort is monitored (for up to many years). Those who develop diseases are compared with like individuals who did not.
- Cross-sectional. An entire population is sampled, with health status and health parameters and risk-modifying factors measured.
- Laboratory studies are generally of 3 types:
- Animal studies. Animal models of various diseases are challenged with various agents.
- Detailed cell and tissue analysis. Cells and tissues from patients can be examined for genetic variations, etc.
- In clinical trials, people are enrolled and randomly assigned to take a substance or a placebo for a specified time. The object is to see whether taking the agent yields a better result for the outcome of interest.