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Adult Stem Cell
Adult stem cells are undifferentiated cells, found throughout the body after development, that multiply by cell division to replenish dying cells and regenerate damaged tissues. Also known as somatic stem cells (from Greek σωματικóς, meaning ''of the body''), they can be found in juvenile, adult animals, and humans, unlike embryonic stem cells. Scientific interest in adult stem cells is centered around two main characteristics. The first of which is their ability to divide or self-renew indefinitely, and the second their ability to generate all the cell types of the organ from which they originate, potentially regenerating the entire organ from a few cells. Unlike embryonic stem cells, the use of human adult stem cells in research and therapy is not considered to be controversial, as they are derived from adult tissue samples rather than human embryos designated for scientific research. The main functions of adult stem cells are to replace cells that are at risk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission Electron Microscopy
Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a grid. An image is formed from the interaction of the electrons with the sample as the beam is transmitted through the specimen. The image is then magnified and focused onto an imaging device, such as a fluorescent screen, a layer of photographic film, or a detector such as a scintillator attached to a charge-coupled device or a direct electron detector. Transmission electron microscopes are capable of imaging at a significantly higher resolution than light microscopes, owing to the smaller de Broglie wavelength of electrons. This enables the instrument to capture fine detail—even as small as a single column of atoms, which is thousands of times smaller than a resolvable object seen in a light microscope. Transmission electron micr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laboratory Rat
Laboratory rats or lab rats are strain (biology), strains of the rat subspecies ''Rattus norvegicus domestica'' (Domestic Norwegian rat) which are bred and kept for scientific research. While Animal testing on rodents, less commonly used for research than laboratory mice, rats have served as an important animal model for research in psychology and biomedical science, and "lab rat" is commonly used as an idiom for a test subject. Origins of rat breeding In 18th-century Europe, wild brown rats (''Rattus norvegicus'') ran rampant and this infestation fueled the industry of rat-catching. Rat-catchers would not only make money by trapping the rodents, but also by selling them rat meat, for food or, more commonly, for rat-baiting. Rat-baiting was a popular sport, which involved filling a pit with rats and timing how long it took for a terrier to kill them all. Over time, breeding the rats for these contests may have produced color variations, notably the albino rat, albino and hoode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Culture
Cell culture or tissue culture is the process by which cell (biology), cells are grown under controlled conditions, generally outside of their natural environment. After cells of interest have been Cell isolation, isolated from living tissue, they can subsequently be maintained under carefully controlled conditions. They need to be kept at body temperature (37 °C) in an incubator. These conditions vary for each cell type, but generally consist of a suitable vessel with a substrate or rich growth medium, medium that supplies the essential nutrients (amino acids, carbohydrates, vitamins, minerals), growth factors, hormones, and gases (Carbon dioxide, CO2, Oxygen, O2), and regulates the physio-chemical environment (Buffer solution, pH buffer, osmotic pressure, temperature). Most cells require a surface or an artificial substrate to form an adherent culture as a monolayer (one single-cell thick), whereas others can be grown free floating in a medium as a suspension culture. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clonogenic Assay
A clonogenic assay is a cell biology technique for studying the effectiveness of specific agents on the survival and proliferation of cells. It is frequently used in cancer research laboratories to determine the effect of drugs or radiation on proliferating tumor cells as well as for titration of Cell-killing Particles (CKPs) in virus stocks. It was first developed by T.T. Puck and Philip I. Marcus at the University of Colorado in 1955. Although this technique can provide accurate results, the assay is time-consuming to set up and analyze and can only provide data on tumor cells that can grow in culture. The word "clonogenic" refers to the fact that these cells are clones of one another. Procedure The experiment involves three major steps: # The treatment is applied to a sample of cells. # The cells are "plated" in a tissue culture vessel and allowed to grow. # The colonies produced are fixed, stained, and counted. At the conclusion of the experiment, the percentage of cells t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
In Vitro
''In vitro'' (meaning ''in glass'', or ''in the glass'') Research, studies are performed with Cell (biology), 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, known as clinical trials, and whole plants. Definition ''In vitro'' (Latin language, Latin for "in glass"; often not italicized in English usage) studies are conducted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unipotent
In mathematics, a unipotent element ''r'' of a ring ''R'' is one such that ''r'' − 1 is a nilpotent element; in other words, (''r'' − 1)''n'' is zero for some ''n''. In particular, a square matrix ''M'' is a unipotent matrix if and only if its characteristic polynomial ''P''(''t'') is a power of ''t'' − 1. Thus all the eigenvalues of a unipotent matrix are 1. The term quasi-unipotent means that some power is unipotent, for example for a diagonalizable matrix with eigenvalues that are all roots of unity. In the theory of algebraic groups, a group element is unipotent if it acts unipotently in a certain natural group representation. A unipotent affine algebraic group is then a group with all elements unipotent. Definition Definition with matrices Consider the group \mathbb_n of upper-triangular matrices with 1's along the diagonal, so they are the group of matrices :\mathbb_n = \left\. Then, a unipotent group can be define ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unipotent Cell
Cell potency is a cell's ability to differentiate into other cell types. The more cell types a cell can differentiate into, the greater its potency. Potency is also described as the gene activation potential within a cell, which like a continuum, begins with totipotency to designate a cell with the most differentiation potential, pluripotency, multipotency, oligopotency, and finally unipotency. Totipotency Totipotency () is the ability of a single cell to divide and produce all of the differentiated cells in an organism. Spores and zygotes are examples of totipotent cells. In the spectrum of cell potency, totipotency represents the cell with the greatest differentiation potential, being able to differentiate into any embryonic cell, as well as any extraembryonic tissue cell. In contrast, pluripotent cells can only differentiate into embryonic cells. A fully differentiated cell can return to a state of totipotency. The conversion to totipotency is complex and not fully ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuron
A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural network in the nervous system. They are located in the nervous system and help to receive and conduct impulses. Neurons communicate with other cells via synapses, which are specialized connections that commonly use minute amounts of chemical neurotransmitters to pass the electric signal from the presynaptic neuron to the target cell through the synaptic gap. Neurons are the main components of nervous tissue in all Animalia, animals except sponges and placozoans. Plants and fungi do not have nerve cells. Molecular evidence suggests that the ability to generate electric signals first appeared in evolution some 700 to 800 million years ago, during the Tonian period. Predecessors of neurons were the peptidergic secretory cells. They eventually ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glial Cell
Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (the brain and the spinal cord) and in the peripheral nervous system that do not produce electrical impulses. The neuroglia make up more than one half the volume of neural tissue in the human body. They maintain homeostasis, form myelin, and provide support and protection for neurons. In the central nervous system, glial cells include oligodendrocytes (that produce myelin), astrocytes, ependymal cells and microglia, and in the peripheral nervous system they include Schwann cells (that produce myelin), and satellite cells. Function They have four main functions: * to surround neurons and hold them in place * to supply nutrients and oxygen to neurons * to insulate one neuron from another * to destroy pathogens and remove dead neurons. They also play a role in neurotransmission and synaptic connections, and in physiological processes such as breathing. While glia w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Offspring
In biology, offspring are the young creation of living organisms, produced either by sexual reproduction, sexual or asexual reproduction. Collective offspring may be known as a brood or progeny. This can refer to a set of simultaneous offspring, such as the chick (young bird), chicks hatched from one clutch (eggs), clutch of eggs, or to all offspring produced over time, as with the brood (honeybee), honeybee. Offspring can occur after mating, artificial insemination, or as a result of cloning. Human offspring (lineal descendant, descendants) are referred to as children; male children are sons and female children are daughters (see Kinship). Overview Offspring contains many parts and properties that are precise and accurate in what they consist of, and what they define. As the offspring of a new species, also known as a child or f1 generation, consist of genes of the father and the mother, which is also known as the parent generation. Each of these offspring contains numerous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multipotency
Cell potency is a cell's ability to differentiate into other cell types. The more cell types a cell can differentiate into, the greater its potency. Potency is also described as the gene activation potential within a cell, which like a continuum, begins with totipotency to designate a cell with the most differentiation potential, pluripotency, multipotency, oligopotency, and finally unipotency. Totipotency Totipotency () is the ability of a single cell to divide and produce all of the differentiated cells in an organism. Spores and zygotes are examples of totipotent cells. In the spectrum of cell potency, totipotency represents the cell with the greatest differentiation potential, being able to differentiate into any embryonic cell, as well as any extraembryonic tissue cell. In contrast, pluripotent cells can only differentiate into embryonic cells. A fully differentiated cell can return to a state of totipotency. The conversion to totipotency is complex and not fully ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Cycle
The cell cycle, or cell-division cycle, is the sequential series of events that take place in a cell (biology), cell that causes it to divide into two daughter cells. These events include the growth of the cell, duplication of its DNA (DNA replication) and some of its organelles, and subsequently the partitioning of its cytoplasm, chromosomes and other components into two daughter cells in a process called cell division. In eukaryotic cells (having a cell nucleus) including animal, plant, fungal, and protist cells, the cell cycle is divided into two main stages: interphase, and the M phase that includes mitosis and cytokinesis. During interphase, the cell grows, accumulating nutrients needed for mitosis, and replicates its DNA and some of its organelles. During the M phase, the replicated Chromosome, chromosomes, organelles, and cytoplasm separate into two new daughter cells. To ensure the proper replication of cellular components and division, there are control mechanisms kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
