Vesicle definition

Although several allelochemicals (primarily phenolic acids and flavonoids) have been shown to inhibit mineral absorption, only the phenolic acids have been studied at the physiological and biochemical levels to attempt to determine if mineral transport across cellular membranes can be affected directly rather than indirectly. Similar and even more definitive experiments need to be conducted with other allelochemicals that are suspected of inhibiting mineral absorption. Membrane vesicles isolated from plant cells are now being used to elucidate the mechanism of mineral transport across the plasma membrane and tonoplast (67, 68). Such vesicle systems actively transport mineral ions and thus can serve as simplified systems to directly test the ability of allelochemicals to inhibit mineral absorption by plant cells. 

CDC Case Definition An illness with acute onset of fever >101°F followed by a rash characterized by firm, deep seated vesicles or pustules in the same stage of development without other apparent cause. Clinically consistent cases are those presentations of smallpox that do not meet this classical clinical case definition (1) hemorrhagic type, (2) flat type, and (3) variola sine eruptione. Laboratory criteria for diagnosis is (1) polymerase chain reaction (PCR) identification of variola DNA in a clinical specimen, or (2) isolation of smallpox (variola) virus from a clinical specimen (Level D laboratory only confirmed by variola PCR). 

Multiple physiological roles for IP6 and the diphosphoinositol polyphosphates have been proposed, including effects on endocytosis and mRNA transport [3] however, definitive evidence for many of these functions is lacking. Such studies are complicated by possible nonspecific effects of this highly negatively charged molecule. Of note is the report of an IP6/IP7-dependent protein kinase activity that phosphorylates pacsin/syndapin I, a protein involved in synaptic vesicle recycling [21]. 

In the OECD test guideline for skin sensitization (OECD TG 406), the following definition is given Skin sensitization (allergic contact dermatitis) is an immunologically mediated cutaneous reaction to a substance. In the human, the responses may be characterized by pruritis, erythema, edema, papules, vesicles, bullae, or a combination of these. In other species, the reactions may differ and only erythema and edema may be seen. ... 

Optic placode—Mild hypoplasia Optic vesicle—Small Optic vesicle—Irregular shape Optic vesicle—Poor definition Optic vesicle—Not evident... 

One pharmacological theory of the mechanism underlying postural hypotension is the false-transmitter theory. Tyramine may be metabolized to an inactive metabolite (octopamine) that partially fills the NE storage vesicles with a false (inactive) transmitter, but definitive proof is lacking. 

Rosenmund C, Stevens CF (1996) Definition of the readily releasable pool of vesicles at hippocampal synapses. Neuron 16 1197-1207... 

The design of artificial self-organizing systems is based on the ability of some molecules which contain simultaneously hydrophobic and hydrophilic groups to form molecular assemblies of definite structure in solution. Examples of the assemblies that can be used to suppress undesirable recombination processes are polyelectrolytes, micelles, microemulsions, planar lipid membranes covering an orifice in a film separating two aqueous solutions, unilamellar vesicles, multilamel-lar vesicles and colloids of various inorganic substances (see reviews [8-18] and references therein). 

Rat liver canalicular membrane vesicles (CMV) have been used to examine the mechanisms of uptake of P-gp substrates such as daunomycin, daunorubicin, and vinblastine, whose biliary excretion is extensive (47,137, 408,409). Early work with plasma membrane vesicles, partially purified from MDR human KB carcinoma cells that accumulated [3H]vinblastine in an ATP-dependent manner, definitively showed how P-gp can act to efflux substrates from cancer cells (410). Additionally, these vesicles have been used to study microscopic aspects of P-gp-mediated efflux, such as the relationship of P-gp function to the membrane fluidity (137). 

The definition of a synapse requires at least the presence of a presynaptic element containing a concentration of vesicles and an apposed postsynaptic element, from which it is separated by the synaptic cleft (Peters et al., 1991). The vesicles of the dopamine synapses are concentrated around the points of synaptic contact rather than around the mitochondria that are part of the varicosities, so the release is probably punctate from the synaptic active zones. Notwithstanding the existence of synaptic specializations and... 

Solubilization can be defined as the preparation of a thermodynamically stable isotropic solution of a substance normally insoluble or very slightly soluble in a given solvent by the introduction of an additional amphiphilic component or components. The amphiphilic components (surfactants) must be introduced at a concentration at or above their critical micelle concentrations. Simple micellar systems (and reverse micellar) as well as liquid crystalline phases and vesicles referred to above are all capable of solubilization. In liquid crystalline phases and vesicles, a ternary system is formed on incorporation of the solubilizate and thus these anisotropic systems are not strictly in accordance with the definition given above. 

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