A sample is one or more parts taken from an ensemble that is studied. A sample is either stored for later quantification or prepared and possibly separated into subsamples, which are enclosed in a system for qualitative or quantitative investigation. A pure sample S is a pure gas, pure liquid or pure solid of a defined elementary entity-type. Then the system used to investigate sample S contains only entities of entity-type S, and the volume VS [L] and mass mS [kg] of the (sub)sample S are identical to the volume V and mass m of the experimental system. A pure sample S may be mixed with other components to be investigated as a mixture, and (sub)sample s is investigated in combination with other components in an experimental system, such that the volume Vs [L] and mass Ms [kg] of the (sub)sample s are smaller than the volume V and mass m of the experimental system. Clarity of statistical representation is improved, if the symbol N is used for the number of primary samples taken from a study group, and the symbol n is used for the number of subsamples studied as technical repeats.
Abbreviation: s, S
Reference: BEC 2020.1
Communicated by Gnaiger Erich last update 2020-05-30
Sample type, sample and subsample
- A sample of a defined sample type subjected to a specific sample preparation (see MitoPedia: Sample preparations) may be, e.g., a mitochondrial preparation obtained from an organ, cells suspended from a cell culture dish, a tissue biopsy, an organ, an individual organism, or a group of organisms (e.g. a number of nematodes studied collectively in an experimental chamber).
- Example: Sample and subsample
- A blood sample or a biopsy taken from an individual organism. The sample size, N, corresponds to the number of replica, e.g., N organisms in a study group (arm). A sample may be processed and split into a number of subsamples (e.g., smaller volumes of blood taken from a larger volume of blood) for (i) application of different types of assay, and (ii) a number of repetitions, n, of the same assay, using subsamples of the same sample.
- A sample is one or more parts taken from a system and intended to provide information on the system, often to serve as a basis for evaluation of the system (diagnosis) or for a decision on intervention (therapy, production process) (ISO 15189:2012 Medical laboratories — Particular requirements for quality and competence).
- The term 'system' is used in this context with reference to a 'study system', distinguished from the 'system' in the context of thermodynamics (open, closed, isolated systems; instrumental chamber).
- Compare: Primary sample.
Application in HRR
Addition of sample to the respirometer chamber
- Isolated mitochondria (imt): Imt are typically added with a Hamilton syringe. Care should be taken to not exert damaging low pressure during aspiration of the sample into the syringe or exerting high pressure during injection into the chamber.
- Living cells (ce) are typically added with a pipette. Care should be taken to not exert damaging low pressure during aspiration of the sample into the pipette or exerting high pressure during injection into the chamber.
- Very large and/or fragile living cells (ce): Some cell types may be easily damaged when injected with a syringe. For these we recommend: remove the Stopper, replace a defined volume of the respiration medium with cell suspension, close the chamber again. Sometimes (i.e. microalgal cells) the whole volume of the chamber (2 mL) is replaced by the cells suspension with the cell concentration adjusted to the desired value.
- PBMCs and Platelets: We recommend adding for PBMC 2·106 x/mL; for PLT 200·106 x/mL.
- Permeabilized tissue (pti): For permeabilized tissue, remove the Stopper, add the permeabilized tissue into the O2k-chamber, close the chamber again.
- Permeabilized muscle fibers (pfi): Remove the Stopper, add the permeabilized fibers into the O2k-chamber, close the chamber again.
- Permeabilized cells (pce): If the cells can be loaded into a syringe, they may be injected with a Hamilton syringe. If the cells are rather fragile, remove the Stopper, replace a defined volume of the respiration medium with cell suspension, close the chamber again.
|MitoFit 2020.4.v0||Gnaiger Erich (2020) A X-mass Carol. From Quantities, Symbols, and Units to Body Mass Excess and mitObesity. MitoFit Preprint Arch 2020.4.v0.|
|BEC 2020.1 doi10.26124bec2020-0001.v1||Gnaiger Erich et al ― MitoEAGLE Task Group (2020) Mitochondrial physiology. Bioenerg Commun 2020.1. doi:10.26124/bec:2020-0001.v1.||2020|
MitoPedia concepts: MitoFit Quality Control System
MitoPedia topics: Sample preparation