Untitled - D Ank Unlimited

density gradient centrifugation 222 dermatographism
Dense deposit disease.
Dense deposit disease.
as a consequence of alternate complement pathway activation.
C4 is normal. Sialic acid-rich glomerular basement
membrane glycoproteins increase in number. Patients
may possess a serum factor, termed nephritic factor, that
activates the alternate complement pathway. This factor
is an immunoglobulin molecule that reacts with alternate
complement pathway-activated components such as the
bimolecular C3b and activated factor B complex. Nephritic
factor stabilizes alternate pathway C3 convertase.
density gradient centrifugation
The centrifugation of relatively large molecules such as
in a solution of DNA with a density gradient substance
such as cesium chloride. This method permits the separation
of different types of cells as they are centrifuged
through a density gradient produced by a substance to
which they are impermeable. A commonly used material
is Ficoll–Hypaque. Separation of cells is according to size
as they progress through the gradient. When they reach the
level where their specific gravity is the same as that of the
medium, cell bands of different density are produced. This
technique is widely employed to separate hematopoietic
cells.
deoxyguanosine
Refer to purine nucleoside phosphorylase (PNP) deficiency.
deoxyribonuclease
An endonuclease that catalyzes DNA hydrolysis.
deoxyribonuclease I
An enzyme that catalyzes DNA hydrolysis to a mono- and
oligonucleotide mixture composed of fragments terminating
in a 5′-phosphoryl nucleotide.
deoxyribonuclease II
An enzyme that catalyzes DNA hydrolysis to a mono- and
oligonucleotide mixture composed of fragments terminating
in a 3′-phosphoryl nucleotide.
deoxyribonucleoprotein antibodies
Antibodies reactive with insoluble deoxyribonucleoprotein
(DNP) that occur in 60 to 70% of patients with active systemic
lupus erythematosus (SLE). Immunoglobulin G (IgG)
DNP antibodies, which fix complement, cause the LE cell
phenomenon and yield a homogeneous staining pattern.
depot-forming adjuvants
Substances that facilitate an immune response by holding
an antigen at the injection site following inoculation. Based
on adjuvant-induced granuloma formation that facilitates
the slow release of antigen over an extended time and helps
attract macrophages and antigen-presenting cells to the site
of antigen deposition. To be effective, the adjuvants must be
administered with the antigen. Water-in-oil emulsions of the
Freund type and aluminum salt (aluminum hydroxide) adjuvants
are examples of depot-forming adjuvants. In the past,
depot-forming and centrally acting adjuvants were distinguished.
However, adjuvant action depends upon far more
complicated cellular and molecular mechanisms than the
simplistic views of depot formation advanced in the past.
dermatitis herpetiformis (DH)
A skin disease with grouped vesicles and urticaria that is
related to celiac disease. Dietary gluten exacerbates the
condition and should be avoided to help control it. Most
patients (70%) manifest no bowel disease symptoms.
Immunoglobulin A (IgA) and C3 granular immune deposits
occur along dermal papillae at the dermal–epidermal
junction. Groups of papules, plaques, or vesicles appear in
a symmetrical distribution on knees, elbows, buttocks, posterior
scalp, neck, and superior back region. The disease is
chronic unless gluten is deleted from the diet. Neutrophils
(PMNs) and fibrin collect at dermal papillae tips, producing
microabscesses. Microscopic blisters, which ultimately
develop into subepidermal blisters, may develop at the
tips of these papillae. These lesions must be distinguished
from those of bullous pemphigoid. DH is associated with
HLA-B8, HLA-DR3, HLA-B44, and HLA-DR7 haplotypes.
dermatitis venenata
Refer to contact dermatitis.
dermatographism
Wheal-and-flare reaction of the immediate hypersensitivity
type induced by scratching the skin. Thus, minor physical
trauma induces degranulation of mast cells with the release