Quiz 4: Anti-infective Coating & Infection Prevention

Question 1

high infection rate from devices is due to

Answer 1

direct exposure to bodily fluids and invasive placement within the body

Question 2

control of biofilm formation: Antimicrobial approaches

Answer 2

Most biomaterials in this category either display or release bioactive molecules, while others promote cell lysis by exposing functional groups that effectively interact with bacteria cell membranes. (Intrinsically bioactive biomaterials: Cationic materials)

Question 3

Biomaterials releasing bioactive molecules

Answer 3

Surface modification with antibacterial agents:
- Antibiotics
- Metal ions
- Nitric oxide

Question 4

Different strategies to apply bioactive molecules to biomaterial surface:

Answer 4

• Physical adsorption (simplest strategy: surface)
• Impregnation inside the biomaterial (bulk, e.g., pores)
• Complexation
• Conjugation

Question 5

Antibiotics

Answer 5

Examples in orthopedic applications:
- Gentamicin (most common)
- Gentamicin + Vancomycin

Antibiotics-loaded (A-L) bone cement (bone cement impregnation)

Coating implant surfaces with biodegradable materials that release antibiotics in a controlled fashion.
- PLGA or PLA polymer as coatings for Titanium (Ti) implants to deliver gentamicin.
- Mesoporous hydroxyapatite, combined with antibiotics as coatings for dental and bone implants.

Question 6

Silver

Answer 6

Silver (Ag+) accumulates at the cellular membrane and leads to membrane perforation. Also, Ag+ promotes the generation of reactive oxygen species.
- Formulations include Ag salts, Ag oxide, metallic Ag, Ag alloy, or Ag nanoparticles (the most active form).
- Silver has been loaded in PLGA coating for Ti implants; commonly used in urinary catheters; successfully used in wound-dressing materials.

Question 7

Low-dose Nitric Oxide (NO)

Answer 7

kill bacteria primarily due to its reactive and toxic effects on microbial cells.
- Generation of Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) that are highly toxic to bacterial cells, damaging essential cellular components like DNA, proteins, and lipids.
- Inhibition of enzymes necessary for bacterial cell wall synthesis, susceptible to lysis.
- NO has been shown to be effective in breaking down biofilms— penetrate biofilms and weaken the bacterial community, making individual bacteria more susceptible to immune cells and treatments.

Question 8

Intrinsically bioactive biomaterials: Cationic materials

Answer 8

Promote cell lysis by exposing functional groups that effectively interact with bacteria cell membranes

Cationic polymers with a net positive charge (backbone or side chain) bind to the negatively charged components of the microbial cell membrane promoting membrane disassembly and leakage or lysis.
- chitosan (in wound dressings, drug formulations, and tissue engineering)
- Antimicrobial peptides (Small cationic peptides, 10-50 amino acids, produced by the innate immune system)
- Synthetic cationic polymers (e.g., Polyethyleneimine (PEI), but has cytotoxicity concerns in human cells)

Question 9

Intrinsically bioactive biomaterials: Cationic materials advantages

Answer 9

long lifetime and low propensity to induce antibiotic resistance.

Question 10

control of biofilm formation: Antifouling approaches

Answer 10

Repel microbes, thereby impairing bacterial adhesion and biofilm formation.
(1) Hydrophilic polymers
a) PEG
b) Zwitterionic materials

(2) Superhydrophobic materials
a) “Lotus leaf effect”, unique self-cleaning and bacterial-fouling resistant properties.
b) Can be obtained by combining hydrophobic moieties with proper micro/nanoscale topography.

(3) Materials with nano/microscale surface texture
Bactericidal surfaces: disrupt bacterial cell, causing death (e.g., dragonfly and cicada wings and geiko skin)

Question 11

Materials with nano/microscale surface texture: nanopillars or nanospikes

Answer 11

Bactericidal Mechanism of nano-
textured surfaces:
Bacteria cell walls stretch and disfigure when they interact with textured surfaces. Stretching occurs in the regions between structures, and if sufficient, cell rupture and death occur.

Question 12

Quorum sensing

Answer 12

bacterial cell-cell communication within biofilms, primarily known
as “quorum sensing,” is facilitated by the secretion of signaling molecules called autoinducers, which build up concentration gradients within the biofilm environment, allowing bacteria to coordinate their behavior based on the local population density.

Question 13

control of biofilm formation: Biomaterials affecting biofilm
architecture

Answer 13

Biomaterials expose enzymes or quorum sensing (QS) molecules that modify biofilm structure and enhance biofilm removal by either physical methods or antibiotic treatments.

Question 14

Biomaterials modified with QS-quenching enzymes

Answer 14

• QS signal molecules include lipids and cyclic or linear peptides.
• Enzymes that degrade these molecules can lead to reduced biofilm thickness, reduced biofilm formation, and interfere with QS pathways

Question 15

Biofilm matrix-degrading enzymes

Answer 15

• Dispersin-B and DNase I
• These two enzymes can degrade components in the biofilm EPS matrix

Question 16

Infection Prevention: general principles of sterilization or disinfection of medical devices

Answer 16

In general, reusable medical devices or patient-care equipment that enters normally sterile tissue or the vascular system or through which blood flows should be sterilized before each use.

Sterilization means the use of a physical or chemical procedure to destroy all microbial life, including highly resistant bacterial endospores.

The major sterilizing agents used in hospitals are a) dry heat, b) moist heat by steam autoclaving, c) ethylene oxide gas, and, d) radiation

Disinfection means the use of a chemical procedure that eliminates virtually all recognized pathogenic microorganisms but not necessarily all microbial forms (e.g., bacterial endospores) on inanimate objects.

Question 17

which of the following best describes the function of an anti-infective coating on a medical device?
it improves the strength and durability of the device
it prevents the adhesion and growth of microoganisms
it promotes biofilm formation on the device surface
it enhances the device’s compatibility with human tissue

Answer 17

It prevents the adhesion and growth of microorganisms

Question 18

which dressing type prolongs silver release for sustained antimicrobial efficacy?
hydrophilic dressing
hydrophobic dressing
no difference
cannot be determined

Answer 18

hydrophobic dressing

Question 19

which property of a biomaterial is most likely to reduce bacterial biofilm formation on a medical implant?
micro-scale roughless
high hydrophobicity
nanoscale roughness
high porosity

Answer 19

nanoscale roughness

Question 20

why are nanotextured surfaces effective in antifouling applications?
they attract bacterial cells with a positive charge, preventing detachment
they make grooves and pits that trap bacteria, making them adhere strongly
they form a hydration layer that prevents bacterial attachment
they have nanoscale features that disrupt bacterial cell walls on contact

Answer 20

they have nanoscale features that disrupt bacterial cell walls on contact

Question 21

true or false: anti-infective coatings can prevent biofilm formation by directly killing bacteria or blocking attachment to surfaces

Answer 21

true

Question 22

true or false: hydrophilic coatings are generally less effective in reducing bacterial adhesion compared to hydrophobic coating

Answer 22

false

Question 23

sterilization

Answer 23

validated process used to render a product free from viable microorganisms
sterile: refers to the absence of microorganisms

Question 24

sterility assurance level (SAL)

Answer 24

probability of a single microorganism being present in a sterilized product. a statistical measurement of the likelihood that a sterilized item is still non-sterile. SAL=10^-6
most processes are designed to overkill sterilization

Question 25

disinfection

Answer 25

reduces the number of pathogens on surfaces. it is usually less effective than sterilization. used for environmental surfaces and non-critical items.

Question 26

factors affecting the outcome and effectiveness of the sterilization process

Answer 26

cleanliness of the material being sterilized nature and extent of initial bioburden design, manufacture, and assembly of device/implant chemistry/reactivity of underlying biomaterials features such as convoluted channels or internal porosity

Question 27

sterilization techniques

Answer 27

radiation sterilization ethylene oxide sterilization

Question 28

thermal sterilization

Answer 28

used mostly in hospital settings paired with established validation processes often not possible when biologics or liquids are added to device or when a combination product is repacked for use (aseptic processing of the product preferred to ensure SAL can be maintained)

Question 29

Sterilization methods for liquid products

Answer 29

use one of the variations of steam sterilization small volume parenteral also might be compatible with radiation sterilization avoid aseptic filtration/fill unless absolutely dictated by product compatibility

Question 30

Sterilization methods for non-liquid products

Answer 30

steam, dry heat, and radiation sterilization are preferred over ethylene oxide these processes are relatively simple and do not leave toxic residues in the product

Question 31

Radiation-based techniques: safety concerns

Answer 31

possible lethal exposure to radiation and ozone inhalation safety measures: shielding and robust interlocks implemented in radiation processing as well as ozone monitors and adequate ventilation

Question 32

Radiation-based techniques used for

Answer 32

mass-produced medical devices bc of its simplicity and convenience in terms of large-scale processing, including sutures, gloves, face masks, syringes, surgical stapler etc

Question 33

Radiation causes

Answer 33

DNA damage in bacteria and viruses preventing pathogens from reproducing and inactivating them.

Question 34

Radiation sterilization occurs through three methods:

Answer 34

gamma, electron beam, x-ray

Question 35

material considerations for radiation sterilization

Answer 35

free radicals cause scission to DNA but may also disrupt material properties of polymers resulting in chain scission or cross-linking, or even reacting with oxygen to damage synthetic or biological materials of the sample material of the product remains inert to the low doses that occur during

Question 36

material considerations for radiation sterilization: mitigating alteration ex

Answer 36

PLGA experiences a decrease in MW after sterilization. changes in MW may alter degradation in vivo and drug release kinetics. this can be accounted for and considered by making the initial MW higher or to conduct radiation sterilization while the product is refrigerated.

Question 37

material considerations for radiation sterilization for biologics and human-based tissue

Answer 37

low dose radiation sterilization method, adding free radical scavengers or radioprotectors (antioxidant ascorbic acid) ex. drug-material combinatorial products such as tissue-engineering scaffolds

Question 38

chemical techniques

Answer 38

machines: bulk EO sterilization machine, tabletop sterilization machine colorless gas, very toxic and flammable requires special equipment with special venting requirements low temperature sterilization method of choice for heat sensitive instruments: plastics, suture material, lenses, finely sharpened instruments materials must be well aerated after sterilization materials/instruments must be dry

Question 39

material considerations for radiation sterilization: ethylene oxide

Answer 39

ethylene oxide functions on the basis of its strong alkylating property, causing disruption of cellular processes, including clotting of proteins, inactivation of enzymes, and disruption of DNA, resulting in preventing the replication of microorganisms. preferred sterilized method for almost half the medical device manufacturing market. also effective for porous dressings and woven materials liquids and powders are not compatible bc the gas has a hard time penetrating them unless spread out in a thin layer

Question 40

other popular chemical agents

Answer 40

hydrogen peroxide and ozone primarily leverage oxidation of the cell walls and proteins, resulting in the destruction of cell walls and even endospores with prolonged contact

Question 41

thermal sterilization

Answer 41

oldest class of sterilization technique. high temperature in both techniques (dry heat and steam) is the main principle of microbial inactivation. kill microorganisms by coagulation of proteins, including structural components of the cells, as well as by rupturing cell walls

Question 42

thermal techniques: dry heat

Answer 42

most convenient method for heat-stable materials such as nonaqueous materials, oil-based injectable pharmaceuticals, powders, glassware, and metallic surigcal instruments uses hot air without added moisture to kill microbes relies on temperature and exposure time (generally high temp (160-330C) for 3 h) typically requires higher temp and longer exposure compared to steam sterilization

Question 43

thermal techniques: steam sterilization

Answer 43

sterilization by steam under pressure is relatively simple involving exposure of the product to steam at the desired temp and pressure. carried out in a pressure vessel designed to withstand high temp and pressure for uniform temp dist: important to remove the air from the sterilization chamber (accompanied by gravity displacement or by a vacuum system) a vacuum system is generally preferred when compatible with the product/package system to ensure efficient air removal and optimum steam penetration moist heat requires significantly reduced heat exposure time compared to dry heat and is nontoxic, rapid, penetrating, and energy efficient

Question 44

steam sterilization: autoclaving

Answer 44

autoclave: self locking machine that sterilizes with steam under pressure sterilization achieved by the high temp that steam under pressure can reach high pressure ensures saturation of wrapped surgical packs ideal for metal instruments typically a drying cycle for sterilizing items that need to be dry for immediate use or storage (surgical instruments, glass, metal tools) drying cycle used for processing materials that would be compromised by residual moisutre

Question 45

steam sterilization advantages and disadvantages

Answer 45

advantages: simplicity, relatively short processing times, lack of toxic residues a combination of high T with moisture has advantages over dry heat such as reduced sterilization time disadvantage: relatively high T, humidity, high pressure may lead to softening, degradation, and hydrolysis of polymer-based materials. not effective at destroying endotoxin

Question 46

steam sterilization use

Answer 46

widely used in hospitals for sterilization of pharmaceuticals in glass ampules, plasticware, and metallic surgical instruments intended for reuse by applying saturates, pressurized steam to be compatible with steam sterilization, a product must be stable with respect to temp and moisture, and the product/package must be readily penetrated by steam

Question 47

prion

Answer 47

misfolded protein that induces misfolding in normal variants of the same protein, leading to cellular death heat-stable meaning it can survive sterilization procedures

Question 48

endotoxins

Answer 48

lipopolysaccharides found in the cell wall of gram-negative bacteria, which can induce inflammation and fever as an immune response in higher organisms heat-stable meaning it can survive sterilization procedures

Question 49

blood coagulation (clotting)

Answer 49

process by which blood changes from a liquid to a gel, forming a blood clot. results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair when artificial surfaces are placed in contact with blood, a complex set of interdependent reactions happen between the surface, platelets, and coagulation proteins

Question 50

which of the following is the primary goal of sterilization? to kill all microorganisms, including spores to reduce the microbial load to a safe level to disinfect surfaces to enhance the appearance of medical instruments

Answer 50

to kill all microorganisms, including spores

Question 51

which method is suitable for sterilization heat-sensitive medical equipment? steam autoclave dry heat sterilization ethylene oxide gas boiling

Answer 51

ethylene oxide gas

Question 52

in a standard steam autoclave, what is the typical temperature and pressure used to ensure effective sterilization? 100C and 10psi 121C and 15psi 160C and atmospheric pressure 180C and 30psi

Answer 52

121C and 15psi

Question 53

which statement best differentiates sterilization from disinfection? sterilization uses steam, while disinfection uses dry heat sterilization completely kills all microbes; disinfection reduces them disinfection kills all bacterial spores; sterilization only reduces them sterilization and disinfection are identical processes in infection control

Answer 53

sterilization completely kills all microbes; disinfection reduces them

Question 54

why is a drying cycle important in an autoclave process when sterilizing reusable biomedical equipment? to enhance the effectiveness of dry heat sterilization to remove moisture that could affect sterility and equipment function to protect moisture-sensitive materials from damage to maintain a high temperature for prolonged sterilization

Answer 54

to remove moisture that could affect sterility and equipment function

Question 55

true or false: dry heat sterilization better eliminates all microbes and spores on biomedical instruments, compared to steam

Answer 55

false

Question 56

true or false: ethylene oxide gas is often used to sterilize biomedical equipment that cannot tolerate high temperatures or moisture

Answer 56

true

Question 57

hemostatsis

Answer 57

process of blood clotting and then the subsequent dissolution of the clot, following repair of the injured tissue crucial in regenerative medicine and tissue engineering bc it provides the initial step in wound healing. the hemostatic mechanism is designed to stop bleeding from injured blood vessels

Question 58

four stages of wound healing (7a slide 5)

Answer 58

hemostasis inflammation proliferation remodeling

Question 59

cellular composition of blood: red cells

Answer 59

passive participants in the process of hemostasis comprise 40-50% of the total blood volume

Question 60

cellular composition of blood: leukocytes (white cell)

Answer 60

perform many functions in inflammation, infection, wound healing, and the blood response to foreign materials, such as monocytes, neutrophils etc

Question 61

cellular composition of blood: platelets

Answer 61

nonnucleated, disk-shaped cells having a diameter of 2-3 um platelets are produced in the bone marrow, circulate in the blood vessels, and occupy ~0.3% of the total blood volume

Question 62

platelet functions

Answer 62

initially arrest bleeding through the formation of platelet plugs stabilize the initial platelet plugs by catalyzing coagulation reactions leading to the formation of fibrin

Question 63

platelet structure: platelet receptors

Answer 63

membrane-bound receptors that mediate the contact reactions of adhesion (platelet-surface interactions) and aggregation (platelet-platelet interactions)

Question 64

cytoplasmic storage granules

Answer 64

α-Granules, which are numerous and contain the platelet-specific proteins platelet factor 4 (PF-4) and β- thromboglobulin (β-TG), and proteins found in plasma (including fibrinogen, albumin, fibronectin, coagulation factors V and VIII). dense granules contain adenosine diphosphate (ADP), calcium ions (Ca2+), and serotonin. Lysosomal granules contain enzymes (acid hydrolases)

Question 65

Hemostasis events that occur in a set order following the loss of vascular integraity

Answer 65

1. vasconstriction (vascular constriction). limits the flow of blood to the area of injury 2. platelet activation. platelets activated by thrombin and aggregate at injury site, forming a temporary, loose platelet plug. the protein fibrinogen is primarily responsible for stimulating platelet clumping. platelets clump by binding to collagen that becomes exposed following rupture of the endothelial lining of vessels. Upon activation, platelets release ADP (Adenosine Diphosphate) and TXA2 (Thromboxane A2) (which activate additional platelets), serotonin, phospholipids, lipoproteins, and other proteins important for the coagulation cascade. In addition to induced secretion, activated platelets change their shape to accommodate the formation of the plug. 3. blood clot. to ensure the stability of the initially loose platelet plug, a fibrin mesh (clot) forms and entraps the plug 4. fibrinolysis & clot degradation. clot must be dissolved in order for normal blood flow to resume following tissue repair. dissolution of the clot occurs through the action of plasmin.

Question 66

platelet activation definition

Answer 66

causes platelets to become sticky and change to irregular spheres with spiny pseudopods

Question 67

platelet activation

Answer 67

platelets bind to matrix and spread to cover the damaged surface; aggregation to form temporary plug - initiates the wound healing process through secretion of soluble small molecules from cytoplasmic granules called growth factors and cytokines, derived growth factor, fibronectin, von willebron factor, and transforming growth factor-beta - these substances are sticky and bind to matrix, chemotactic (draw cells up the concentration gradient through migration) and/or mitogenic agents for leukocytes, endothelial cells and fibroblasts

Question 68

Hemostasis: Vasoconstriction & Plug Formation

Answer 68

1. exposed collagen binds and activates platelets 2. release of platelet factors 3. attract more platelets 4. aggregate into platelet plug

Question 69

fibrin clot formation - thrombogenesis

Answer 69

process by which a blood clot (thrombus) forms through the conversion of fibrinogen to fibrin by the action of thrombin fibrin stabilizes the platelet plug and seals the site of injury to prevent further blood loss

Question 70

fibrin clot formation - thrombogenesis pathways

Answer 70

two main pathways: converse upon a final common pathway, which leads to the formation of thrombin and an insoluble fibrin gel when thrombin acts on fibrinogen both pathways are complex and involve numerous proteolytic enzymes called clotting factors

Question 71

thrombogenesis intrinsic pathway

Answer 71

clot in response to an abnormal vessel wall superficial injury in the absence of tissue injury longer and slower compared to extrinsic can take between a few seconds or minutes to produce factor X more Factor X produced than extrinsic

Question 72

thrombogenesis extrinsic pathway

Answer 72

clot formation in response to tissue injury, actual breakage of blood vessels reacts almost instantaneously by producing factor X main function is to augment the intrinsic pathway by slowing the flow of blood outside the vessel by producing little Factor X but quickly completes the clot and allows for the blood vessel to be repaired

Question 73

coagulation & clot stabilization

Answer 73

clotting factors (proenzymes) interact in a sequential series of enzymatic activation reactions (coagulation cascade), leading to amplified production of the enzyme thrombin, which in turn cleaves fibrinogen to form a fibrin polymer that stabilizes the clot or thrombus

Question 74

platelet coagulant activity

Answer 74

when platelets aggregate, platelet coagulant activity is initiated including the expression of negatively charged membrane phospholipids, which accelerate two critical steps of the blood coagulation sequence: factor X activation and the conversion of prothrombin to thrombin

Question 75

thrombin

Answer 75

key enzyme that plays a central role in blood clotting. once formed from its proenzyme, prothrombin, thrombin not only converts fibrinogen into fibrin (to form a clot) but also activates other clotting factors

Question 76

activatable factors

Answer 76

clotting factors that exist in an inactive form (proenzymes or precursors) and need to be activated to participate in the clotting process. thrombin triggers their activation, allowing them to contribute to the formation and stabilization of a blood clot factors like factor V,VIII,XIII are examples of clotting factors that can be activated by thrombin

Question 77

Factors V,VIII,XIII activation

Answer 77

Va: cofactor in the conversion of prothrombin to thrombin VIIIa: plays role as cofactor in the intrinsic pathway XIIIa: helps cross-link fibrin strands to stabilize the clot

Question 78

dissolving the clot and anticoagulants

Answer 78

the fibrinolytic system removes unwanted fibrin deposits to improve blood flow following thrombus formation and to facilitate the healing process after injury and inflammation

Question 79

plasmin

Answer 79

plasmin: most well-studied fibrinolytic enzyme, circulates in an inactive form as the protein plasminogen

Question 80

plasminogen

Answer 80

adheres to fibrin clot being incorporated into the mesh during polymerization activated to plasmin by the actions of plasminogen activators, which may be present in blood or released from tissues, or which may be administered therapeutically

Question 81

Important plasminogen activators

Answer 81

tissue plasminogen activator (tPA) and urokinase

Question 82

following activation of plasminogen

Answer 82

plasmin digests the fibrin clot, releasing soluble fibrin-fibrinogen digestion products (FDP) into circulating blood, which may be assayed as markers of in vivo fibrinolysis

Question 83

fibrinolysis is inhibited by

Answer 83

plasminogen activator inhibitors (PAIs) and by a thrombin-activated fibrinolysis inhibitor (TAFI) which promotes the stabilization of fibrin and fibrin clots

Question 84

fibrinolytic sequence

Answer 84

Plasminogen activators, such as tissue plasminogen activator (tPA) or urokinase, activate plasminogen to form plasmin. Plasmin enzymatically cleaves insoluble fibrin polymers into soluble degradation products (FDPs), thereby effecting the removal of unnecessary fibrin clot.

Question 85

blood material interactions

Answer 85

There are two primary mechanisms through which thrombus formation is initiated from contact between blood and artificial materials: 1. interaction between platelets with the material surface, which is mediated by adsorbed proteins, leading to platelet activation 2. contact-activation of the intrinsic clotting cascade directly by the material surface

Question 86

thrombus formation induced by platelet adhesion on a synthetic material surface

Answer 86

(A) Adsorption of plasma proteins to material surface. (B) Conformational changes in adsorbed proteins followed by the adhesion of nonactivated platelets from the blood stream. (C) Platelet activation leading to the release of activating factors. (D) Platelet aggregation and the activation of the blood coagulation cascade leading to thrombus formation, along with the subsequent activation of complement and inflammatory processes.

Question 87

granulocyte

Answer 87

any blood cell containing specific granules (neutrophils, eosinophils, basophils)

Question 88

leukocyte

Answer 88

colorless blood cell capable of ameboid movement (lymphocytes, monocytes, granulocytes)

Question 89

macrophage

Answer 89

large phagocytic mononuclear cell

Question 90

ameboid

Answer 90

describes the adaptable, flowing movement of certain cells that allows them to move and interact with their surroundings, similar to the way an ameoba moves. they have the ability to change shape and move by extending and retracting pseudopodia (temporary projections of the cell membrane) to crawl or move

Question 91

what is the first step in the hemostasis process?

Answer 91

vasoconstriction

Question 92

which enzyme is responsible for converting fibrinogen to fibrin during clot formation?

Answer 92

thrombin

Question 93

what role does factor XIII play in the coagulation process

Answer 93

cross-links fibrins to stabilize the clot

Question 94

which of the following statements about platelets is true? platelets are the main component of the clotting cascade platelets adhere to the exposed collagen at the site of injury platelets do not play a role in the release of clotting factors platelets dissolve the fibrin clot after it is formed

Answer 94

platelets adhere to the exposed collagen at the site of injury

Question 95

what is the main function of plasmin in the hemostasis process? to form the initial platelet plug to activate thrombin dissolve the fibrin clot during fibrinolysis convert fibrinogen to fibrin

Answer 95

dissolve the fibrin clot during fibrinolysis

Question 96

true or false: thrombin is responsible for activating multiple clotting factors, including factor V and factor VIII

Answer 96

true

Question 97

true or false: fibrin degradation products (FDPs) are insoluble fragments formed during clot formation

Answer 97

false soluble and formed during clot degradation

Question 98

true or false: the intrinsic and extrinsic pathways of the coagulation cascade converge at the activation of factor X

Answer 98

true