on 31-Jul-2016 (Sun)

because a FRA is traded on an interest rate and a futures contract is traded on a price, FRAs and futures are in opposite directions

Selectivity depicts a molecule with greater affinity for one receptor
(or
any process for that matter) over another. The key is that implicit
in this
definition (or rather characterization), is that the selectivity can be
"overcome" by overloading the system, and the "other" receptor
experiences
binding and/or activation.

Specificity takes selectivity one step further, where no increase in the
ligand or molecule of interest can activate the other receptor(s).

Here are my two cents:

The words selectivity, specificity, and sensitivity (derived from
Latin seligere, specificus, sensitivus), can be confusing terms as
they are often used synonymously in the medical literature. However,
they should not be used interchangeably as each represents a different
phenomenon:

The word selectivity describes a drug's ability to affect a particular
cell populationin preference to others. Selectivity is generally a
worthy property in a drug because a drug having high selectivity may
have a dramatic effect when there is a single agent that can be
targeted against the appropriate molecular-driver involved in the
pathogenesis of a disease. Selectivity is used to describe the
ability of a drug to affect a particular population, i.e., gene,
protein, signaling pathway, or cell, in preference to others. For
example a selective drug would have the ability to discriminate
between cell or receptor populations, and so affect only one cell
population, and thereby produce an event.

Specificity, a term most often confused with selectivity, is used to
describe the capacity of a drug to cause a particular action in a
population. For example, a drug of absolute specificity of action
might decrease or increase, a specific function of a given gene or
protein or cell type, but it must do either, not both.

Sensitivity is used to describe the capacity of a population, to
respond to a drug's ability, to stimulate that entity at a specified
dose. The smaller the dose required producing an effect, the more
sensitive is the responding system. (The word used to describe this
activity in the drug which is the cause of the population sensitivity,
is potency).

A method is specific if it produces a response for only one single
analyte. Since it is almost impossible to develop a chromatographic
assay for a drug in a biological matrix that will respond to only the
compound of interest, the term selectivity is more appropriate.
Selectivity of a method is its ability to produce a response for the
target analyte which is distinguishable from all other responses (e.g.
endogenous compounds).

If a drug has one effect, and only one effect on all biological systems it possesses the property of specificity. In experience, the vast majority of drugs are selective rather than specific. This is the case because most drugs will act on more than one receptor site once they reach an appropriately high concentration. Two examples include: a) verapamil, a blocker of L-type Ca channels, but which blocks Na channels at high concentrations; b) yohimbine a drug used therapeutically as an α2-adrenoceptor blocker but which also blocks 5-HT receptors, α1-adrenoceptors, Na channels, monoamine oxidase, and cholinesterase at higher concentrations. The concentration range over which a drug produces its therapeutic effect is known as its therapeutic window. An illustration of the therapeutic window for selective blockade of α2-adrenoceptors by yohimbine is shown in Figure 11.

Although the phenotypes of genetic diseases are diverse, their causes are not. Th e primary cause of any genetic disease is a change in the sequence or cellular content of DNA that ultimately deranges gene expression.

Most genetic diseases are caused by an alteration in DNA sequence that alters the synthesis of a single gene product.

Some genetic diseases are caused by (1) structural rearrangements that result in deletion or duplication of a group of closely linked genes or (2) abnormalities during mitosis or meiosis that result in an abnormal number of chromosomes per cell.

Furthermore, as we'll shortly see, the relations between mental agents are not always strictly hierarchical.

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