The Term Dose

The term dose appears frequently when discussing pharmacological therapy. Although the concept of dose initially appears quite simple, it is not easy to define unequivocally. As Heilman (2006) observed, it can refer to  

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Equiactive (equieffective) molar concentration (potency) ratios (EMR, EPMR), variants of the term dose ratio or equiactive dose ratios. Usually pertaining to agonists, these are the molar concentrations that produce the same response in a given system. These ratios are dependent on the affinity and efficacy of the agonists and thus are system independent, that is, characterize agonists and receptors in all systems. Care must be taken that the maximal responses of the agonists concerned are equal. 

Dose" as defined here refers to the absorption of radiation energy by human tissue. Higher doses correspond to higher potential for adverse health effects, as described in Chapter 3. The terms dose and exposure are often used interchangeably. 

Note that, to call attention to an important source of variability in the onset time, we used the term dose onset factor (Donset). As stated, it represents the decrease in Tonso, (the time at which NF performance first falls below 25% of baseline) when the incapacitating dose (IDso) is doubled. In the case of BZ, for example, doubling the absorbed dose shortens the Tonso from four hours to less than an hour. Doubling it again presumably shortens it to just a few minutes. This would be an important concept for military plarmers to consider. Our data were insufficient to measure the Domet precisely because we preferred not to administer double doses to volunteers, hr the few cases in which actual aerosol doses were considerably higher than the intended value, however, the dramatically earlier onset of incapacitation allowed an educated guess of the Donset. 

As no international consensus has been achieved in the OECD/IPCS project (OECD 2003a) in order to differentiate between dose (concentration)-response (effect) relationship and because it in reality is difficult to understand the subtle differences in the different terms as defined in the OECD/IPCS project, the broader and more general definition provided in the TGD (EC 2003) will be used in this book, and will generally be referred to as dose-response. Consequently, the term dose will, in this book, generally mean both dose and exposure concentration unless otherwise stated. 

Johns would like to restrict the term exposure to the measure of incident light energy, and the term dose to the measure of light energy absorbed.11... 

Therefore, we can identify two types of relationship with the dose of the toxicant a dose-effect relationship (graded effect) and a dose-response relationship (all-or-none effect). However, the term "dose-response relationship" is often used to describe both types. 

In radiation biology, the term "dose" has a specific meaning. Dose refers to the amount of radiation absorbed by the organ or tissue of interest per unit mass and is expressed in rads (grays). 

The term dose has different meanings for radionuclides and hazardous chemicals. In assessments of risk to human health, this term generally refers to energy imparted to tissue and its biological significance for radionuclides, but it usually refers to mass intakes for hazardous chemicals. 

The formation of a polymer networks starts with an increase in molecular weight and formation of branched structures. At a typical extent of reaction, the gelation point is that point at which a network is first formed. The extent of reaction as well as the cross-linking density in radiation-induced cross-linking processes is determined by the radiation dose. The term dose means the quantity of radiation applied to or absorbed accidentally by a given volume or mass of sample. The absorbed dose is measured in Gray (Gy), 1 Gy = 1J kg-1. Therefore, the formation of a polymeric network needs a certain dose, the gelation dose Dg, which can be determined by sol-gel analysis. ... 

Because of the uncertainty in dose delivery and the relatively benign nature of many inhaled medications used in past years, large quantities were often delivered from nebulizers to assure results. The term dose overkill will... 

Everyone is generally familiar with the term dose, or dosage, as it is used to describe the use of medicines. A single tablet of regular strength... 

The term dose means here the quantity of radiation applied to or absorbed accidentally by a given volume or mass of sample. The absorbed dose Is measured in Gray (Gy), 1 Gy = IJ/kg. 

And since dose/V X = (AUC)o following the administration of a single intravenous bolus dose, substituting for the term dose/WC in Eq. 11.17 with the term (AUC)o yields the following equation ... 

The "average" plasma concentration is always directly proportional to the dose administered (linear pharmacokinetics). The term dosing... 

The amount of radiation delivered to a specified area or the whole body. Dose rate is the dose delivered per unit of time. The term dose- or dosage- is also used generally to express the amount of energy or substance absorbed in a unit volume by an organ or individual. 

The term dose level has been used instead of loading to indicate additive concentrations. It can be assumed that a dose level of x% means x% by weight, not volmne. 

In general, to assess the delayed effects of current exposure, dose quantities of the ionizing radiations are introduced. The term dose is used in a general sense as a measure of the quantity of radiation or the energy deposited by radiation in a target. For the strictest use in dosimetry, the term must be specified as absorbed dose, equivalent dose, organ dose, etc. These quantities may refer to exposed individuals (individual dose) or to a group of people (collective dose). 

The term dose refers to the sum of the effective dose from external e q>osure in a givmi period and the committed effective dose from radionuclides taken into the body in the same period. 

The term dose—response in environmental epidemiology is typically understood to mean that quantitative relationship in which adverse effect severity and multiplicity increase in proportion to the intensity of exposure or dose indexed externally (intake/uptake quantities) or internally (exposure biomarkers). In the case of experimental animal exposures, reference is often to the administered dose, but biomarkers can also be available. Dose—response has also been employed to denote impacts at some selected effect level of a toxicant in terms of increasing affected fractions of some population as exposure increases. In this case, a dose—population response label is more precise. 

Throughout this book the term dose is used to denote the sum of the effective dose equivalent resulting from external exposure during one year and the committed effective dose equivalent from that year s intake of radionuclides. 

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