Studies that are in vivo 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, 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.
In vitro studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology and its subdisciplines are traditionally done in labware such as test tubes, flasks, Petri dishes, and microtiter plates. Studies conducted using components of an organism that have been isolated from their usual biological surroundings permit a more detailed or more convenient analysis than can be done with whole organisms; however, results obtained from in vitro experiments may not fully or accurately predict the effects on a whole organism. In contrast to in vitro experiments, in vivo studies are those conducted in living organisms, including humans, and whole plants.
In vitro toxicity testing is the scientific analysis of the effects of toxic chemical substances on cultured bacteria or mammalian cells. In vitro testing methods are employed primarily to identify potentially hazardous chemicals and/or to confirm the lack of certain toxic properties in the early stages of the development of potentially useful new substances such as therapeutic drugs, agricultural chemicals and food additives.
In situ is a Latin phrase that translates literally to "on site" or "in position." It can mean "locally", "on site", "on the premises", or "in place" to describe where an event takes place and is used in many different contexts. For example, in fields such as physics, geology, chemistry, or biology, in situ may describe the way a measurement is taken, that is, in the same place the phenomenon is occurring without isolating it from other systems or altering the original conditions of the test.
Animal Free Research UK (AFRUK), formerly the Dr Hadwen Trust, is a UK medical research charity that funds and promotes non-animal techniques to replace animal experiments. Established in 1970, the work undertaken by Animal Free Research UK develops reliable science whilst avoiding animal testing.
In biology and other experimental sciences, an in silico experiment is one performed on computer or via computer simulation. The phrase is pseudo-Latin for "in silicon", referring to silicon in computer chips. It was coined in 1987 as an allusion to the Latin phrases in vivo, in vitro, and in situ, which are commonly used in biology. The latter phrases refer, respectively, to experiments done in living organisms, outside living organisms, and where they are found in nature.
Biomedicine is a branch of medical science that applies biological and physiological principles to clinical practice. Biomedicine stresses standardized, evidence-based treatment validated through biological research, with treatment administered via formally trained doctors, nurses, and other such licensed practitioners.
Ex vivo literally means that which takes place outside an organism. In science, ex vivo refers to experimentation or measurements done in or on tissue from an organism in an external environment with minimal alteration of natural conditions. Ex vivo conditions allow experimentation on an organism's cells or tissues under more controlled conditions than is possible in in vivo experiments, at the expense of altering the "natural" environment.
Streblus asper is a tree known by several common names, including Siamese rough bush, khoi, serut, and toothbrush tree. It is a medium-sized tree native to dry regions in Indonesia, Cambodia, Thailand, India, Sri Lanka, Malaysia, and Vietnam.
In chemistry, a substrate is typically the chemical species being observed in a chemical reaction, which reacts with a reagent to generate a product. It can also refer to a surface on which other chemical reactions are performed, or play a supporting role in a variety of spectroscopic and microscopic techniques. In synthetic and organic chemistry, the substrate is the chemical of interest that is being modified. In biochemistry, an enzyme substrate is the material upon which an enzyme acts. When referring to Le Chatelier's principle, the substrate is the reagent whose concentration is changed. The term substrate is highly context-dependent.
Prostaglandin D2 (or PGD2) is a prostaglandin that binds to the receptor PTGDR (DP1), as well as CRTH2 (DP2). It is a major prostaglandin produced by mast cells – recruits Th2 cells, eosinophils, and basophils. In mammalian organs, large amounts of PGD2 are found only in the brain and in mast cells. It is critical to development of allergic diseases such as asthma. Research carried out in 1989 found PGD2 is the primary mediator of vasodilation (the "niacin flush") after ingestion of niacin (nicotinic acid).
In vitro maturation (IVM) is the technique of letting the contents of ovarian follicles and the oocytes inside mature in vitro. It can be offered to women with infertility problems, combined with IVF, offering women pregnancy without ovarian stimulation.
A dry lab is a laboratory where computational or applied mathematical analyses are done on a computer-generated model to simulate a phenomenon in the physical realm. Examples of such phenomena include a molecule changing quantum states, the event horizon of a black hole or anything that otherwise might be impossible or too dangerous to observe under normal laboratory conditions. This term may also refer to a lab that uses primarily electronic equipment, for example, a robotics lab. A dry lab can also refer to a laboratory space for the storage of dry materials.
Forkhead box protein K1 is a transcription factor of the forkhead box family that in humans is encoded by the FOXK1 gene.
Simcyp Limited is a research-based company which provides modelling and simulation software to the pharmaceutical industry for use during drug development. Simcyp is based in Sheffield, UK.
Safety pharmacology is a branch of pharmacology specialising in detecting and investigating potential undesirable pharmacodynamic effects of new chemical entities (NCEs) on physiological functions in relation to exposure in the therapeutic range and above.
In natura is a phrase to describe conditions present in a non-laboratory environment, to differentiate it from in vivo and ex vivo conditions.
In vitro to in vivo extrapolation (IVIVE) refers to the qualitative or quantitative transposition of experimental results or observations made in vitro to predicts phenomena in vivo, biological organisms.
An in silico clinical trial is an individualised computer simulation used in the development or regulatory evaluation of a medicinal product, device, or intervention. While completely simulated clinical trials are not feasible with current technology and understanding of biology, its development would be expected to have major benefits over current in vivo clinical trials, and research on it is being pursued.
Yamini Dalal is an Indian American biochemist specialized in chromatin structure and epigenetic mechanisms. She is a senior investigator at the National Cancer Institute.