Untitled - D Ank Unlimited

diazo salt 227 differentiation
Diapedesis.
diazo salt
A diazonium salt prepared by diazotization from an arylamine
to yield a product with a diazo group. Diazotization
has been widely used in the preparation of hapten–carrier
conjugates for use in experimental immunology.
diazotization
A method to introduce the diazo group into a molecule. Karl
Landsteiner used this technique extensively in coupling low
molecular weight chemicals acting as haptens to protein macromolecules
serving as carriers. Aromatic amine derivatives
can be coupled to side chains of selected amino acid residues
to prepare protein–hapten conjugates that stimulate the
synthesis of antibodies when used to immunize experimental
animals such as rabbits. Some of these antibodies are specific
for the hapten, which alone is unable to stimulate an immune
response. An aromatic amine reacts with nitrous acid generated
through the combination of sodium nitrite with HCL,
then the diazonium salt is combined with the protein at a pH
that is slightly alkaline. The reaction products include monosubstituted
tyrosine and histidine and also lysine residues that
are disubstituted.
DIC
Abbreviation for disseminated intravascular coagulation.
Dick test
A skin test to signify susceptibility to scarlet fever in subjects
lacking protective antibody against the erythrogenic toxin
of Streptococcus pyogenes. A minute quantity of diluted
erythrogenic toxin is inoculated intradermally. An area of
redness (erythema) occurs at the injection site 6 to 12 hours
following inoculation of the diluted toxin in individuals who
do not have neutralizing antibodies specific for the erythrogenic
toxin and are therefore susceptible to scarlet fever. A
heat-inactivated preparation of the same diluted toxin is also
injected intradermally in the same individual as a control
against nonspecific hypersensitivity to other products of the
preparation.
differential RNA processing
Derivation of two structural forms of a protein from a single
gene at the polyadenylation level. Numerous polyadenylation
sites are situated following two or more exons. Primary RNA
transcripts of varying lengths, including different exon and
intron subsets, will be formed based on the particular site
chosen for cleavage and polyadenylation. This process leads
to proteins with alternative C terminal amino acid sequences.
differential signaling hypothesis
A proposal that antigens that differ qualitatively may
mediate positive and negative selection of thymic T
lymphocytes.
differentiation
Process whereby a developing precursor cell or an activated
cell achieves functional specialization.
HN CH CO
AsO3H2 AsO3H2 Alkaline
CH2 AsO3H2 H2N 0–4°
Acid + nitrite
N N
solution
N N
Arsanilic acid
HN CH
OH
CH 2
CO
Tyrosine residue
Diazotization.
Intracutaneous
injection
Erythrogenic toxin
inoculation causes the
skin to redden in 24–48
hours in susceptible individuals
OH
Dick test.
D