Term
|
Definition
ΔG = ΔH −TΔS (chemical reactions are spontaneous when
ΔG < 0 ) |
|
|
Term
|
Definition
H, a measure of the amount of energy in a
system available for mechanical work |
|
|
Term
|
Definition
| S, a measure of the disorder of the system |
|
|
Term
| three factors on protein adsorption |
|
Definition
Dehydration, redistribution of charged groups, structural
rearrangement |
|
|
Term
|
Definition
|
|
Term
|
Definition
Since the bonds between amino acids are called peptide bonds,
are a kind of polymers. proteins are also called polypeptides. Polypeptides are formed
via condensation reactions |
|
|
Term
|
Definition
linear order of amino acids as dictated by
the codons. has a fundamental influence
in all other levels of structures. Example, substitution of a single amino acid in the polypeptide chain that composes
hemoglobin, the protein that carries oxygen in the blood,
changes its overall folded shape and results in the disease
known as sickle cell anemia |
|
|
Term
|
Definition
caused by localized interactions between
amino acid residues. α -helix structure is one of the two most common types of
secondary structures. β -pleated sheet structure is another one of the two most
common types of secondary structures |
|
|
Term
|
Definition
three-dimensional arrangement of an
entire polypeptide chain It shows the secondary structural
elements are folded. A common example is triosephosphate
isomerase (TIM)-barrel fold (this distinctive structure has eight
parallel β -strands surrounded by eight α -helices on the
outside) |
|
|
Term
|
Definition
describes the three-dimensional
arrangement of the polypeptide chains. If there are one, two,
three, and more chains, it is monomer, dimmer, trimer, etc,
respectively When pH changes, protein structures are changed, which
subsequently changes the adsorption of proteins on the surface
of a biomaterial. |
|
|
Term
| Transport of proteins to surface is affected by |
|
Definition
diffusion, thermal convection, flow (also called
convective transport), coupled transport (combinations
of others, such as convection and diffusion). Transport phenomena due to flow, thermal convection, and
diffusion |
|
|
Term
|
Definition
given by V = 2Q/(μR^2)*[1-(r/R)^2], where V is the
velocity, Q is the volumetric flow rate of liquid through the cylinder, μ is the viscosity, and r and R are radial distance and
the radius of vessel, respectively |
|
|
Term
| The protein transport equation |
|
Definition
given by ∂C/∂t + V*∂C/∂z = D*1/r*∂/∂r*(r ∂C/∂r), where C stands for the concentration of a protein at time t ,
position z (axial), and r in a vessel, V is the velocity, D is
diffusion coefficient (this equation only describes the transport
of the protein through a solution, but not the rate of transport of
protein to the surface) |
|
|
Term
| Monolayer protein coverage |
|
Definition
Rearrangement of proteins on a surface to allow more proteins
to be adsorbed to the surface, which explains why the rate
adsorption increase after a slow down |
|
|
Term
|
Definition
| Proteins may first be adsorbed to the surface loosely |
|
|
Term
|
Definition
then change their conformation to bind to
the surface permanently |
|
|
Term
|
Definition
a phenomenon where proteins with higher
concentration will rapidly attach, and then be replaced over
time by proteins with greater surface affinity |
|
|
Term
|
Definition
Initially adsorbed proteins may be exchanged by other proteins
with a stronger affinity to the surface |
|
|
Term
| Adsorption chromatography |
|
Definition
is one type of affinity
chromatography. It measures the time that proteins stick to a
particular chemical analyte (column) in the instrument to
determine the types of proteins contained in the sample
injected. Proteins that stick strongly to the column will come
out later |
|
|
Term
| types of adsorption chromatography |
|
Definition
normal
phase chromatography (more hydrophilic molecules are euted
later); and (2) reverse-phase chromatography (more hydrophilic
species are eluted first) |
|
|
Term
| Ion exchange chromatography |
|
Definition
another type of adsorption
chromatography, but its discussion is beyond the scope of the
text. |
|
|
Term
|
Definition
are the simplest test for the presence of a
given protein involves direct reaction of the component with a
marker chemical to cause a specific color change (the molecule
causing this specific color is called chromophore) |
|
|
Term
|
Definition
are similar to the colorimetric assays but
here the reaction causes the attachment of a fluorescing
molecule (fluorophore) to the protein of interest. After the attachment of fluorophore in the protein smaple,
visible light of specific wavelengths is used to excite the
molecules in the sample and the fluoresced lights are detected. are able to quantify fluorescently labeled
protein molecules |
|
|
Term
|
Definition
an instrument that uses fluorescence to
identify proteins |
|
|
Term
| advantages of fluorescent assays |
|
Definition
the
fluorescent phenomena are detectable at one to three orders of
magnitude lower concentration than that observable with
traditional colorimetric (absorbance) techniques; and if the
protein of interest contains enough of amino acids that are
intrinsic fluorophores, an additional reaction to label the protein
is unnecessary. |
|
|
Term
| enzyme-linked immunosorbent assay (ELISA) |
|
Definition
used to
determine in the sample the amount of proteins that are specific
to a given antibody. |
|
|
Term
|
Definition
which uses an antibody to identify proteins
and measure their amount through a spectrophotometer |
|
|
Term
|
Definition
used to determine the protein types
(different sizes) in the initial sample |
|
|
Term
| Sodium dodecyl sulfate (SDS) |
|
Definition
used to treat the sample first
before the western blotting process so that the proteins are
strongly negatively charged and can be attracted to the positive
electrode |
|
|
Term
reversed-phase
chromatography |
|
Definition
Areas of curves of reversed-phase HPLC chromatographs can
be used to determine the amount of certain separated species
present in the original sample |
|
|
Term
| There are two stimuli for activation of platelets |
|
Definition
exposure to
soluble factors, and interaction with extracelluar matrix
(ECM) and/or cells of injured vessel walls |
|
|
Term
|
Definition
nonnucleated fragments of megakaryocytes with a
diameter of 3-4 μm and a half-life of 8-12 days |
|
|
Term
| Two main hemostatic functions of platelets are |
|
Definition
initially
reduce bleeding through the creation of a platelet plug, and further stabilize this plug through activation of the blood
coagulation cascade |
|
|
Term
| collagen and von Willebrand factor (vWF) |
|
Definition
| arepotent platelet activators |
|
|
Term
| The sequelae of activation of platelets are |
|
Definition
change their
shapes from disc-like to irregular form, and release of stored
granule contents due to a contraction of cytoskeletal proteins in
the platelets. |
|
|
Term
| The function changes of activated platelets are |
|
Definition
adhere to
ECM proteins, aggregate, secrete various bioactive
factors for further platelet stimulation, and exhibit
coagulatory activity (promote localized blood coagulation). |
|
|
Term
| Intrinsic and extrinsic pathways |
|
Definition
Both pathways result in a
common pathway that converts fibrinogen to fibrin, the main
constituent of the blood clot. |
|
|
Term
|
Definition
are substances that bind calcium and are very
effective anticoagulants (calcium is needed to form
coagulation). |
|
|
Term
|
Definition
is initiated by trauma to blood itself or
exposure of blood to exposed extracellular matrix (ECM)
molecules in a damaged vessel wall. It begins with adsorption
of one of the coagulation contact proteins, Factor XII, to a
negatively charged surface |
|
|
Term
|
Definition
is initiated by the release of tissue factor
(TF) and clotting can commence via this pathway within 15
seconds. |
|
|
Term
|
Definition
depends on the activations of stimulated
platelets. |
|
|
Term
|
Definition
an enzyme that is extremely important substance
in the coagulation cascade, with both pro- and anticoagulant
activities. It cleaves fibrinogen to form fibrin monomer and
fibrinopeptides that can be polymerized to form long fibrin
fibers for blood clotting. Thrombin is synthesized and released
by platelet. It catalyzes the production of more thrombin and
stimulates adenosine diphosphate (ADP) and thromboxane A2
release. |
|
|
Term
| Two means of coagulation control |
|
Definition
physiological factors
(such as normal blood flow), and soluble and insoluble
biochemical factors (soluble agents may bind coagulation
factors and inhibit their actions and insoluble substances such
as thrombomodulin that is found on the endothelial surface of
the blood vessel walls plays a large role in the control of
coagulation) |
|
|
Term
|
Definition
is required to restore normal blood flow to the
damaged area. It occurs primarily via fibrinolysis, or cleavage
of the fibrin fibers in a controlled manner |
|
|
Term
|
Definition
the interior wall of a blood vessel. It has a
number of anticoagulative properties in its native state but it
will be a main mechanism of coagulation initiation after injury
where the protective glycocalyx is compromised |
|
|
Term
|
Definition
a coating of endothelium and imparts smoothness
to the walls of the vessel |
|
|
Term
| Five categories of hemocompatibility that need to be tested |
|
Definition
thrombosis, coagulation, platelets, hematology, and
immunology (complement and leukocyte activation) |
|
|
Term
| Local and systemic effects |
|
Definition
local effects are localized blood
clotting that could negatively affect device function, and systemic effects of device-mediated coagulation include
thrombus embolization, in which pieces of the clot break off
and are carried elsewhere in the circulatory system. |
|
|
Term
Both local and systemic effects from blood contacting devices
can result from the following three factors |
|
Definition
blood characteristics, flow regime, and material surface
characteristics. |
|
|
Term
There are four quantifiable parameters for in vitro test of
hemocompatibility |
|
Definition
coagulation time, amount of adhered
platelets, mass of adherent thrombus, amount of platelet
granule released (this requires specific assays for chemical
mediators found in platelet granules, such as platelet factor-4
and β –thromboglobulin) |
|
|
Term
| In vitro hemocompatibility tests |
|
Definition
have a low cost but have a
limited value for prediction of in vivo responses |
|
|
Term
| Factors to consider for in vivo hemocompatibility tests include |
|
Definition
choice of animal, length of study and choice of time
points, and inclusion of proper control materials. |
|
|
Term
| Ex vivo hemocompatibility tests |
|
Definition
are in vivo tests but they place
devices being tested outside of body and use tubes to connect
them with blood vessels in the body. |
|
|
Term
|
Definition
a nonspecific immunity that is the first line
of defense. |
|
|
Term
|
Definition
a specific immune response that involves
the activation of a type of white blood cell called lymphocyte |
|
|
Term
|
Definition
if the organism persists after exposure to
both the innate and acquired immune response. |
|
|
Term
|
Definition
|
|
Term
| There are several types of leukocytes |
|
Definition
granulocytes (can be subdivided into neutrophils, eosinophils
and basophils), monocytes (have a large phagocytic
capability), lymphocytes/plasma cells (part of the acquired
immune response), and megakaryocytes (in the bone
marrow to produce platelets). |
|
|
Term
|
Definition
from the pluripotent hematopoetic
stem cell. |
|
|
Term
| Leukocytes are only present |
|
Definition
in the blood to be transported to a
tissue where they are needed. |
|
|
Term
There are four main components of the defense provided by
innate immunity |
|
Definition
anatomic barriers (skin and mucous
membranes), physiologic barriers (temperature of body, low
pH or acidic in stomach),phagocytic cells (granulocytes),
and inflammation (tissue swelling when one gets injured). |
|
|
Term
| There are four clinical signs of inflammation |
|
Definition
rubor
(redness), tumor (swelling),tumor (swelling), dolore (pain). |
|
|
Term
|
Definition
a part of innate immunity and is an
immediate response to tissue injury. |
|
|
Term
|
Definition
a symptom persists over
weeks to months |
|
|
Term
|
Definition
a movement of the neutrophils out of the blood
vessels and into the tissue |
|
|
Term
| There are four steps of migration of neutrophils |
|
Definition
| rolling, activation, arrest and adhesion, and migration. |
|
|
Term
| A main task of neutrophils |
|
Definition
to phagocytose foreign agents.
This process is called phagocytosis |
|
|
Term
|
Definition
a glucose metabolism that is increased up
to tenfold and oxygen consumption increased two- to threefold,
which leads to the formation of reactive oxygen and nitrogen
species (radicals and strong oxidizers) in intracellular granules
and then released to kill foreign organisms |
|
|
Term
|
Definition
are secreted by neutrophils to have specific effects
on several cell types, such as, attract lymphocytes and attract
more neutrophils |
|
|
Term
|
Definition
at the injury site five to six hours after the
inflammatory response begins (partially due to the signals
released by the neutrophils). |
|
|
Term
|
Definition
enlarged monocytes. They mature in up to
eight hours and involve swelling of the cell and formation of a
large quantity of lysosomes |
|
|
Term
|
Definition
in the same way as for neutrophils but
an individual macrophage can engulf many more bacteria or
particles than a neutrophil. |
|
|
Term
|
Definition
is observed if the size of the
nondegradable material is much larger than that of the cell |
|
|
Term
|
Definition
| are secreted by activated macrophages |
|
|
Term
| Effects of some or all of the chemical mediators are |
|
Definition
effects
on the inflammatory response, effects on the acquired
immune response, and systemic effects |
|
|
Term
| antigen-presenting cell (APC) |
|
Definition
is a key function of
the macrophage (provides a direct connection between the
innate and acquired immune responses) |
|
|
Term
|
Definition
eosinophils (have a smaller phagocytic
capacities as compared to neutrophils/macrophages, but they
are important because they destroy parasites and detoxify some
of the inflammation-inducing agents), and basophils
(similar to mast cells that release heparin, histamine, bradykinin
and serotonin, which are soluble mediators of inflammation) |
|
|
Term
| Acute inflammation is terminated |
|
Definition
as the stimulus for acute
inflammation is removed |
|
|
Term
Indicators of activation of leukocyte (that are most commonly
neutrophils or macrophages) due to biomaterials are |
|
Definition
cell
adhesion and spreading, cell death, cell migration, cytokine release, and cell surface marker expression. |
|
|
Term
|
Definition
generally examine one or more indicators of
activation of leukocyte. |
|
|
Term
Cell characterization via fluorescence-activated cell sorting
(FACS) |
|
Definition
is based on immunostaining techniques (see
Chapter 9) for tagging antibody to the receptor of interest on
the inflammatory cells |
|
|
Term
| Test of response of endothelial cells |
|
Definition
is a further in vitro assay
for the inflammatory potential of biomaterials |
|
|
Term
The upregulation of cell surface receptors or ligands on
endothelial cells |
|
Definition
promotes the migration of neutrophils and
macrophages and thus is a key step in the inflammatory
response. |
|
|
Term
| three major stages for wound healing |
|
Definition
acute
inflammation, chronic inflammation, and granulation
tissue formation |
|
|
Term
|
Definition
a tissue characterized histologically by a
pebbly, granular appearance (thus its name) |
|
|
Term
| Neovascularization or angiogenesis |
|
Definition
the process of production
of granulation tissue that is formed by the creation of many
vascular buds sprouting from existing blood vessels. |
|
|
Term
|
Definition
are some of the fibroblasts that take on features
of smooth muscle cells. They are responsible for wound
contraction, which results in faster healing due to a decrease in
the overall defect size |
|
|
Term
The foreign body reaction is dependent on several factors
associated with the implant |
|
Definition
surface properties of the
material (smooth surfaces invoke only macrophages that are
only one to two cells in thickness, while rough surfaces may
have a mixture of macrophages and FBGCs); and the shape
of the implanted material (in particular, a high surface area to
volume ratio will have higher ratios of macrophages and
FBGCs at the tissue-material interface, while implants with a
lower surface area to volume ratio show more fibrous or
granulation tissue production) |
|
|
Term
|
Definition
a process that involves foreign body
giant cells (FBGCs) and the elements of granulation tissue |
|
|
Term
|
Definition
the final stage of healing for implants
made from nondegradable materials |
|
|
Term
There are four factors on degree of long-term capsule
formation |
|
Definition
degree of original injury during implantation, amount of subsequent cell death, location of implant site,
and degradation time of implant (if degradable) |
|
|
Term
| four factors on thickness of the capsule |
|
Definition
| amount and composition of small particulates produced, mechanical factors at implant site, shape of implant, and electrical currents (if produced). |
|
|
Term
| Size of the fibrous capsule |
|
Definition
increases in proportion to the rate of
shedding of small particulates, which can be caused by
corrosion, degradation, and wear |
|
|
Term
|
Definition
may correspond to current density of
electrodes. |
|
|
Term
|
Definition
characterized by the presence of
mononuclear cells, including lymphocytes and plasma cells,
which may also indicate that the material has triggered an
acquired immune response. It is also less uniform histologically
than acute inflammation. |
|
|
Term
|
Definition
to restore to the body’s status quo after injury
through inflammation and wound healing response |
|
|
Term
| There are four main types of possible resolutions |
|
Definition
extrusion
(force materials out of body), resorption (implant is
biodegradable), integration (in limited cases such as
implantation of pure titanium in bone), and encapsulation
(traditional response to nonresorbable materials). |
|
|
Term
| The two processes to form functional tissues are |
|
Definition
repair (for
deeper wounds); and regeneration (for small wounds). |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
a reepithelialization (for smaller skin
wounds that are contained in the epidermal layer and a full
regeneration of the defect are possible). |
|
|
Term
Factors that are related to a biomedical implant that may affect
the in vivo response |
|
Definition
the material(s); intended additives,
process contaminants, and residues; leachable substances; degradation products; other components and their
interactions in the final produce; and the properties and
characteristics of the final product. |
|
|
Term
There are four means of in vivo biological responses for the
factors that are related to the biomedical implant |
|
Definition
interactions of biological molecules or cells with the implant, interactions of biological molecules or cells with soluble
agents leached from the implant, interactions of biological
molecules or cells with insoluble particulates, and alterations in load or strain in the area around the implant (can
be caused by material properties, but is also affected by
geometry and final properties of the device). |
|
|
Term
|
Definition
the ability of a medical device to perform
with an appropriate host response in a specific application |
|
|
Term
| Biocompatibility assessment |
|
Definition
to measure the magnitude and
duration of the adverse alterations in homeostatic mechanisms
(includes carcinogenicity, hemocompatibility, immune
response, and the inflammatory response). |
|
|
Term
| proper selection of animal species is based upon |
|
Definition
on a similarity in
physiology and healing response to that which would occur in
humans for a given application. |
|
|
Term
| Implant site in an animal |
|
Definition
should be the site that is as close as
possible to that which will be used in the final application |
|
|
Term
| There are four different lengths of study |
|
Definition
acute toxicity (up
to 24 hours), subacute toxicity (14-28 days), subchronic
toxicity (within the first 90 days or less than 10% of the
lifetime of the animal), and chronic toxicity (longer time). |
|
|
Term
| There are four factors of “Dose” |
|
Definition
implant weight and/or
bulk size, implant surface area, implant topography, and number of implants per animal. |
|
|
Term
|
Definition
| means effects of the shape of the implant material. |
|
|
Term
| In histology/immunohistochemistry |
|
Definition
tissues containing the
implant are sectioned and stained, either with conventional dyes
or antibodies, after explantation. |
|
|
Term
| two forms of microscopy that can be used to examine tissue response to an implant |
|
Definition
transmission electron microscopy (TEM) and scanning
electron microscopy (SEM) |
|
|
Term
|
Definition
help assess inflammation after
biomaterial implantation. |
|
|
Term
|
Definition
used to test explanted specimens
including the implant and surrounding tissue on a mechanical
testing frame. |
|
|
Term
| Three additional effects of biomaterials are |
|
Definition
| infection, tumorigenesis, and pathologic calcification. |
|
|
Term
| There are nine characteristics of implant-associated infections |
|
Definition
presence of biomaterial and/or damaged underlying
extracellular matrix (ECM), bacterial colonization of tissue, resistance to host defense mechanisms and antibiotic
therapy, presence of characteristic bacteria types, transformation of relatively innocuous bacterial species into
virulent organisms by the presence of a biomaterial, presence of multiple bacteria species, persistence of
infection until removal of the substratum, absence of
integration of the biomaterial with the host, and presence of
cell damage or necrosis. |
|
|
Term
Three organisms that are most often responsible for
biomaterial-related infection |
|
Definition
gram-positive bacteria
(staphylococcus aureus and staphylococcus epidermidis), gram-negative bacteria (Enterobacteriaceae and pseudomonas
aeriginosa), and fungi (candida spp). |
|
|
Term
| Superficial immediate infection |
|
Definition
occurs if there is growth of
microorganisms on the skin in association with an implant (e.g.
growth under burn dressings) |
|
|
Term
|
Definition
occurs at the implant site soon after
surgery |
|
|
Term
|
Definition
may occur months to years after the implantation
surgery |
|
|
Term
| There are four stages of a clinical infection |
|
Definition
bacterial
attachment (to the surface of biomaterial), adhesion
(binding with receptor-ligand interactions), aggregation
(divide and form colonies, exude an extracellular
polysaccharide slime to form biofilm, which may occur as early
as one day after bacterial attachment), and dispersion
(carrying a portion of the bacterial colony to other areas of the
body, which may occur as soon as two days after initial
bacterial attachment). |
|
|
Term
|
Definition
a film that protects the microorganisms from
phagocytosis by neutrophils or tissue macrophages and
provides a favorable environment for bacterial growth |
|
|
Term
An ideal biomaterial surface would have two simultaneously
characteristics |
|
Definition
bacteria resistant; and cell friendly; both
of which are directly related to the type of proteins that adsorb
to the material. |
|
|
Term
| Gram-positive bacteria species |
|
Definition
have a single bilayered
phospholipids membrane and a thick cell wall composed of
peptidoglycan. |
|
|
Term
Gram-negative bacteria species possess two phospholipids
membranes |
|
Definition
the cell membrane; and an outer membrane
with a thin peptidoglycan cell wall between the membranes. |
|
|
Term
|
Definition
Certain species of both gram-positive and gramnegative
bacteria have such an outer layer composed of
polysaccharides that form the cell capsule. |
|
|
Term
|
Definition
is an exudation of slime that forms a
specialized microenvironment (a microzone) that allows the
bacterial to trap ions important to their survival and protects
them from the body’s natural defenses (several types of bacteria
can be housed under a single biofilm coating). |
|
|
Term
|
Definition
| a 100 times greater concentration of oral antibiotics is needed to kill them |
|
|
Term
Two important biomaterial surface properties that affect the
adhesion of bacteria are |
|
Definition
| surface hydrophobicity and charge. |
|
|
Term
| The two physical properties on bacteria adhesion are |
|
Definition
steric
concerns; and surface roughness |
|
|
Term
|
Definition
have effects on the adhesion of bacteria. For
example, the type of proteins found in the media (solvent)
surrounding the material will affect bacteria adhesion. |
|
|
Term
| Nonspecific interaction involved in bacterial adhesion |
|
Definition
is
modeled based on the work from Derjaguin, Landau, Verway,
and Overbeek (DLVO) theory. In the case of specific interaction, receptors and ligands can
extend into the media to promote binding and overcome the
energy barrier depicted in the DLVO model. Microbial surface components recognizing adhesive matrix
molecules (MSCRAMMs) are receptors of many bacteria for a
variety of ECM components |
|
|
Term
| Implant-associated infections |
|
Definition
are unique in that they are usually
caused by transformation of relatively innocuous bacterial
species into virulent organisms by the presence of a biomaterial
(implanted biomaterial plays a compounding role in infection). |
|
|
Term
|
Definition
can be quantified using contact angle
measurements. |
|
|
Term
| Microbial adherence to hydrocarbons (MATH) |
|
Definition
is another
technique to assess bacterial hydrophobicity |
|
|
Term
| Hydrophobic interaction chromatography (HIC) |
|
Definition
is a more
quantitative assessment of the degree of bacterial
hydrophobicity. |
|
|
Term
| Electrophoretic mobility test |
|
Definition
used for testing the surface
charge of bacteria surface. |
|
|
Term
| Electrostatic interaction chromatography (EIC) |
|
Definition
an alternative
method to quantify the bacterial surface charge |
|
|
Term
| In vitro infection testing |
|
Definition
focuses on quantification of bacterial
adhesion to biomaterials under static or well-defined flow
conditions. |
|
|
Term
| Ex vivo models of infection |
|
Definition
involve the use of external shunts
connected to vessels, much like those described for
hemocompatibility testing. |
|
|
Term
| In vivo models of infection |
|
Definition
use both small animals (rodents)
and larger animals. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| an excessive and uncontrolled cell proliferation |
|
|
Term
|
Definition
a tumor that is composed of proliferating
neoplastic cells and surrounding connective tissue and blood
vessels |
|
|
Term
|
Definition
tumors that do not invade adjacent tissues or
spread to distant sites. |
|
|
Term
|
Definition
tumors that invade surrounding tissues
and gain entry into lymph and blood vessels, so they can be
transported to distant sites (this is called tumor metastasis). |
|
|
Term
|
Definition
a stimulus that causes malignant transformation
that is thought to occur due to mutations in the DNA of normal
cells (mutagenesis). |
|
|
Term
|
Definition
not a carcinogen in its native form, but can be
converted to one by metabolic processes found in vivo |
|
|
Term
|
Definition
possesses little or no inherent mutagenic
potential, but enhances the activity of pro- or complete
carcinogens. |
|
|
Term
| three stages of tumorigenesis |
|
Definition
| initiation, latency (may be on the order of 15-20 years), and promotion. |
|
|
Term
|
Definition
is tumor-causing substances that have
leached from the implant (hydrocarbon-based molecules are
usually carcinogens) |
|
|
Term
| Foreign body carcinogenesis |
|
Definition
caused by solid implants with
even no chemical carcinogenic activity (the ability of the
material to induce malignant transformation increases with the
size of the implant). |
|
|
Term
There are six possible causes of foreign-body carcinogenesis of
large implants |
|
Definition
bulk chemical properties, physicochemical surface properties, viral contamination, interruption of cellular communication (due to the presence of
the implant), local tissue damage (leading to insufficient
nutrient exchange), and disturbed cellular growth (around
the implant). |
|
|
Term
| Small fiber tumorigenesis |
|
Definition
Certain cancers have been
implicated by small fibers (less than 1 μm in diameter and more
than 8 μm in length), regardless of their chemical composition
(discovered in humans who have inhaled asbestos fibers and developed a type of cancer known as
mesothelioma). |
|
|
Term
| implant-related tumorigenesis |
|
Definition
| is relatively low for humans |
|
|
Term
|
Definition
used to test for mutagenic potential (all
carcinogens are mutagens). |
|
|
Term
|
Definition
a commonly used method of predicting mutagenic
potential (a mutant bacteria line that requires the amino acid
histidine for growth and thus only non-histidine-dependent
phenotype will be able to survive and proliferate in histidinefree
media if the biomaterial causes the bacteria to mutate). |
|
|
Term
| In vivo carcinogenesis assessment |
|
Definition
generally undertaken as a
part of general biocompatibility testing, as suggested by ISO
and ASTM guidelines |
|
|
Term
|
Definition
an undesired formation of nodules of
calcium phosphate within or on the surface of an implanted
material (on devices such as cardiac valves, blood pumps,
urinary prostheses, and soft contact lenses). |
|
|
Term
|
Definition
denotes the deposition of inorganic material in a
tissue. |
|
|
Term
|
Definition
denotes a subset of mineralization in which
calcium is the major specific inorganic material deposited in the
tissue |
|
|
Term
| Initiation of calcium deposits |
|
Definition
thought that the calcium
deposits are initiated on dead cells or cell membrane fragments
(on proteins with attached phosphate groups that may act as nucleation sites to form calcium phosphate crystals) of
pretreated natural materials (pretreated with gluteraldehyde or
formaldehyde). |
|
|
Term
| There are three factors of pathologic calcification |
|
Definition
host
metabolism, surface and bulk properties of the biomaterial
chosen, and the mechanical environment of the device. |
|
|
Term
| One way to reduce the occurrence of pathologic calcification |
|
Definition
target calcium phosphate crystal initiation (including
localized release of inhibitors of calcium-phosphate crystal
formation such as trivalent metal ions, Fe3+ or Al3+). |
|
|
Term
| In vitro studies of calcium deposition |
|
Definition
can be performed with
materials or entire devices placed in a bath containing media
approximating the chemical composition of a particular in vivo
location (e.g., urine or blood). |
|
|
Term
There are two types of in vivo experiments for pathologic
calcification |
|
Definition
subcutaneous implantation (the material to be
tested is placed under the skin, usually in mice or rats, although
rabbit models are sometimes used), and insertion of the final
device directly at the target location. |
|
|
Term
|
Definition
is to test degree of calcium deposition (for
both in vitro and in vivo experiments). |
|
|
Term
| In histological techniques |
|
Definition
samples are stained and examined
with a light microscope and other methods such as electron
microscopes |
|
|
Term
| Innate response to an implanted material |
|
Definition
is a nonspecific
response. |
|
|
Term
| Acquired immune response to an implanted material |
|
Definition
is a
response to specific portions of the biomaterial (or proteins
adsorbed on the biomaterial) and is mediated by lymphocytes
circulating constantly in the blood and tissues. |
|
|
Term
|
Definition
refers to adverse effects on the function of the
immune system or other body systems as a result of alterations
in immune system function |
|
|
Term
| There are four characteristics of acquired immune response |
|
Definition
| specificity (B and T cells respond to antigens), diversity, self/nonself recognition, and immunologic memory |
|
|
Term
| There are two types of acquired immunity |
|
Definition
humoral (based
on the actions of antibodies against foreign substances) and cellular (utilizes specialized lymphocytes, or T cells, to detect
altered self cells such as those from viral infections or cancer). |
|
|
Term
The major histocompatibility complex (MHC) Class I
molecules |
|
Definition
transmembrane glycoproteins that are found on
almost all nucleated cells in conjunction with a smaller protein,
β 2-macroglobulin. |
|
|
Term
|
Definition
transmembrane glycoproteins
having α and β chains. |
|
|
Term
|
Definition
are inherited from both parents (three loci
each) and thus are different from person to person, and should
be tested for organ transplants |
|
|
Term
|
Definition
is to determine how similar the MHC molecules
are between the host and donor |
|
|
Term
|
Definition
such as viral proteins or proteins
produced in cancerous cells reside within a host cell |
|
|
Term
|
Definition
are produced outside the host cell and
ingested by phagocytosis. |
|
|
Term
| There are two main types of lymphocytes |
|
Definition
|
|
Term
|
Definition
B cells are processed in bone marrow and
further matured in the peripheral lymphoid tissues (lymph
nodes and spleen). |
|
|
Term
|
Definition
T cells are formed in the bone marrow and
mature in the thymus. |
|
|
Term
| Activation of lymphocytes |
|
Definition
Both T and B cells are ultimately
activated through the presence of antigens |
|
|
Term
|
Definition
are produced by lymphocyte rapid mitosis,
forming a clonal population of cells that all are specific to that
antigen after activation. |
|
|
Term
| There are two types of B cells |
|
Definition
memory B cells (express
membrane-bound antibodies) and effector B cells or plasma
cells (producing soluble antibodies). |
|
|
Term
| There are five main classes of antibodies |
|
Definition
|
|
Term
There are four mechanisms for antibodies to remove a
pathogen |
|
Definition
agglutination (multiple large particles with
antigens on their surfaces are bound into a clump by
antibodies), precipitation (it takes place when the complex
of antibody and antigen becomes very large so that they are no
longer soluble), neutralization (antibodies bind and cover the active or toxic sites on a foreign substance), and (4) lysis
(direct attack on the cell membrane of an invading organism by
certain antibodies). |
|
|
Term
| There are two main types of T cells |
|
Definition
| Helper T cell (Th), and cytotoxic T cell (Tc). |
|
|
Term
|
Definition
are those that acquired immune deficiency syndrome
(AIDS) destroys, rendering the AIDS patients defenseless to
diseases. |
|
|
Term
| Effector and memory Th cells |
|
Definition
Once activated, Th cells form a
clonal population including effector and memory Th cells |
|
|
Term
There are four actions of cytokines that are secreted by effector
Th cells |
|
Definition
stimulation of B cell (growth and differentiation), stimulation of Tc cell proliferation, further stimulation of
Th cell activation, and promotion of chemotaxis and
activation of macrophages |
|
|
Term
Effector and memory Tc cells (cytotoxic T lymphocytes or short
for CTLs) |
|
Definition
come from Tc cells. CTLs secrete perforins, which
lyse cells by using mechanisms that are similar to the
membrane attack complex of the complement system to be
discussed below. |
|
|
Term
|
Definition
is a part of innate immunity but it is highly
interrelated with the acquired immune response (it is composed
of over 20 plasma proteins involved in a cascade that ultimately
causes the elimination of foreign elements). |
|
|
Term
|
Definition
forms pores with diameters of 70-
100Ǻ on cell membranes to allow continuous leakage of ions
and small molecules to kill foreign cells |
|
|
Term
| Regulation of the complement system |
|
Definition
is needed to confine the
effects of the complement system to a localized area and
prevent host cells from being lysed by mechanisms intended to
kill only foreign pathogens |
|
|
Term
| Effects of the complement system |
|
Definition
Complement system
activation often amplifies the actions of antibodies. |
|
|
Term
There are several undesired effects of the acquired immune
response |
|
Definition
donor organ rejection, autoimmune disease,
and allergies |
|
|
Term
|
Definition
means compatibility with
the innate immune system |
|
|
Term
| Hypersensitivity reaction |
|
Definition
an allergic reaction, which is an
undesired immune response mediated by the acquired immune
system (even with synthetic biomaterials). |
|
|
Term
| IgE mediated (type I) allergy |
|
Definition
is caused by plasma cells (effector
B cells) that secrete IgE molecules specific for the allergen |
|
|
Term
| Antibody mediated (type II) allergy |
|
Definition
is caused by antibodies
work alone or in connection with the complement system to
destroy cells or platelets presenting a foreign antigen on their
surface |
|
|
Term
| For immune complex mediated (type III) allergy |
|
Definition
the symptoms
may appear days to weeks after original exposure to the antigen
because, in this type of hypersensitivity, both antigen and antibody must be present in the tissue or circulation at the same
time. It is the mechanism of action of autoimmune diseases
such as lupus |
|
|
Term
| T cell mediated (type IV) allergy |
|
Definition
is a delayed-type
hypersensitivity since the symptoms can appear 24-72 hours
after the second contact with the allergen (antigen) |
|
|
Term
|
Definition
Evidence of type IV response to polymers
remains controversial (chemical additives used in the
manufacture of latex gloves may cause this type of
hypersensitivity). |
|
|
Term
|
Definition
Litigation has been filed alleging that
silicone breast implants caused autoimmune diseases
(destruction of body tissues due to unchecked acquired immune
response) and thus many of the major makers of these implants
decided to withdraw from the market in 1992. Subsequent
settlements cost these companies billions of dollars and one
manufacturer was forced into bankruptcy. However, after years
of study that found no direct link between silicone breast
implants and these diseases, in 2006 the U.S. FDA approved a
new generation of these implants for use in cosmetic surgeries |
|
|
Term
| There are six markers for T and B cells |
|
Definition
cell adhesion and
spreading, cell death, cell migration (lymphocyte
migration inhibition assay that is used to determine if a
lymphocyte is activated), cytokine release, cell surface
marker expression, and cell proliferation (lymphocyte
transformation tests or LTTs) |
|
|
Term
| An unresolved immune response |
|
Definition
will have characteristics
similar to chronic inflammation, but includes the presence of
lymphocytes as well as inflammatory cells |
|
|
Term
he most common means of
assessment after implantation in an animal model |
|
Definition
is
histology/immunohistochemistry, with an emphasis on
visualizing the amount of lymphocytes present around the
material. |
|
|
Term
|
Definition
the placement of
possible antigens from the biomaterial on/under the skin to look for localized inflammation |
|
|
Term
| Monitor the immune response |
|
Definition
can be accomplished by taking blood samples from the animal
periodically without euthanizing it |
|
|
Term
Biomaterials should support all functions of attached cells.
These functions include |
|
Definition
Viability (all cell types, often
associated with adhesion/spreading on substrate); communication (all cell types); protein synthesis (all cell
types); proliferation (some cell types); migration (some
cell types); activation/differentiation (some cell types); and programmed cell death (some cell types). |
|
|
Term
| Protein-surface interaction |
|
Definition
|
|
Term
|
Definition
is often specific (usually occur via
receptor-ligand interactions). |
|
|
Term
| three general types of cytoskeletal elements |
|
Definition
| Actin microfibrils, intermediate filaments, and microtubules |
|
|
Term
| Endoplasmic reticulum (ER) |
|
Definition
| responsible for protein synthesis |
|
|
Term
|
Definition
tight junctions (membrane to
membrane contact), ap junctions (small, hydrophilic
channels), and desmosomes (mechanical attachments of two
cells) |
|
|
Term
| Receptor molecules include |
|
Definition
cadheins, selectins, mucins, integrins, and other cell adhesion molecules
(CAMs). |
|
|
Term
|
Definition
contain carbohydrates (glycan) that take the form
of long chains of polysaccharides (sugars) called
glycosaminoglycans (GAGs). |
|
|
Term
The chemical structure of the polysaccharide component of the
most common glycosaminoglycans (GAGs) include |
|
Definition
hyaluronic
acid (HA), keratin sulfate (KS), chondroitin/dermatan sulfate
(CS or DS), heparin sulfate (HS), and heparin |
|
|
Term
|
Definition
are a type of “glue” to link various tissue
components. They are found in the extracellular environment
(ECM). |
|
|
Term
ECM molecules, particularly collagen and certain types of
proteoglycans |
|
Definition
can be used as biomaterials to reduce unwanted
immune responses and the risk of material “rejection.” |
|
|
Term
| Gene expression can affect the following functions of cells |
|
Definition
| cell viability, proliferation, differentiation, and protein synthesis |
|
|
Term
| Cell proliferation has three types |
|
Definition
labile (continuously
differentiate), permanent (terminally differentiated), and stable (between labile and permanent). |
|
|
Term
| Mesenchymal stem cells (MSCs) |
|
Definition
have the potential to
differentiate through a number of different pathways to form
mesenchymal tissues such as bone, cartilage, muscle, tendon,
ligament, and adipose tissue. |
|
|
Term
| Collagen synthesis has the following steps in sequence |
|
Definition
The portion of chromatin coding for collagen becomes less
compact, allowing enzymes that “unzip” the double helix to
separate the DNA strands; Transcription: The enzymes, called RNA polymerases, then
synthesize linear mRNA strands that are complementary to the
collagen gene on the DNA using the base-paring technique.
Every three bases in the mRNA will form a codon for a specific
amino acid (out of a total of 20 different amino acids that are
building blocks for proteins). After fabrication, the mRNA
strand moves out of the nucleus through nuclear pores and enter
the ER in the cell; Translation: In the ER, tRNA (translation RNA), which acts
adaptor molecules and possess binding sites for a specific
amino acid on one end and the mRNA molecule on the other.
The binding site of the tRNA for the mRNA is a series of three
bases known as the anticodon; The process of translation has three stages: initiation,
elongation, and termination. In the initiation process, mRNA
interacts with a small ribosomal subunit and then also with a
larger ribosomal subunit that has two binding sites to hold two
tRNA molecules which assemble amino acids according to the
codons in mRNA. The elongation process will continue the
amino acid assembly until reaching a termination signal in the
mRNA codes, which initiates the termination process. The
termination process will first end the amino acid assembly to
complete the production of the protein, and then dissolve the
ribosomal subunits; Post-translational process: The completed protein (a fully
formed collagen pro-α chain) will move into the ER lumen and
then go through the process in both ER and Golgi to associate
three pro-α chains to form a procollagen molecule. The
procollagen molecules will be secreted into the ECM to further
stabilize the triple-helical structure to form fibril and finally the
fiber assembly. |
|
|
Term
|
Definition
based on Derjaguin, Landau, Verway, and
Overbeek. It is a basic model for cell adhesion to a surface. There are many limitations of the DLVO theory since many
factors have not been included. In addition, the important
receptor-ligand interaction is not considered. The model of receptor-ligand complex concentration over time
is given by a further model: dC/dt = kf*RL - kr*C where kf and kr are
the reaction rates of complex formation and dissociation, and
where R , L, and C represent the concentrations of the free
receptor, free ligand, and receptor-ligand complex,
respectively. However, it is possible to combine these models with the
DLVO theory to make a more accurate prediction of cellsubstrate
adhesion, taking intro account both specific and
nonspecific interactions |
|
|
Term
|
Definition
integrin receptors of cell membrane
interact with ligands on the material surface to firmly anchor
the cell in place. |
|
|
Term
|
Definition
is to test if cells die when directly contact
biomaterials that are toxic to cells |
|
|
Term
|
Definition
is to test if cells die when contact
biomaterials that are toxic to cells through a buffer of agar
layer |
|
|
Term
|
Definition
used to determine the cytotoxicity of leachable
molecules found in biomaterials, such as nonreacted monomers
or degradation products. used to determine the cytotoxicity of leachable
molecules found in biomaterials, such as nonreacted monomers
or degradation products. used to determine the cytotoxicity of leachable
molecules found in biomaterials, such as nonreacted monomers
or degradation products. The elution from the biomaterials is added to cell wells and the
cell viability is tested after certain period of time of cell growth,
say, 24 hours, at body temperature (37 degrees centigrade). |
|
|
Term
| Parallel plate flow chamber |
|
Definition
used for testing cell adhesion and
spreading. The number of cells washed away is an indication of
the cell adhesion ability |
|
|
Term
|
Definition
used to determine if there is direct
damage to a cell’s DNA caused by a biomaterial |
|
|
Term
The reverse-transcription polymerase chain reaction (RT-PCR)
process |
|
Definition
similar to that of PCR, except that the starting
material to be analyzed is mRNA, which needs to have a
reverse transcription to obtain single strand DNA (ssDNA) to
use the normal PCR process. |
|
|
Term
|
Definition
similar to the Southern blotting but it is for
RNA only |
|
|
Term
|
Definition
used to quantify and locate
proteins in a thin section of tissue (determine where and how
much specific proteins have been produced or synthesized). |
|
|
