Tidbits Flashcards by Madison Shubert

Define the following:
Primary wound closure (First intention healing)
Delayed primary wound closure
Secondary Closure (Third intention healing)
Second intention healing

Primary wound closure = Sutured wounds
Delayed primary wound closure = suturing 2-5 days after initial injury, before granulation tissue development
Secondary Closure = Closure of the would after granulation tissue has formed in the wound bed
Second intention healing = Allow to heal without suturing - usually via contraction and epithelialization

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What are the 3 divisions of the vascular supply to the skin?

Superficial/Subpapillary plexus
Middle/Cutaneous plexus
Deep/subdermal/subcutaneous plexus

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What are the main differences between the cutaneous angiosomes in dogs and cats?

Dogs have a greater density of collateral SQ vessels
Cats have a smaller number and wider distribution of cutaneous perforating vessels

These differences apply mainly to the trunk

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What is the reported % strength of wounded skin in comparison to normal skin at the following time points:
14 days
3-4 weeks
Several months

14 days - 5-10% strength
3-4 weeks - 25%
Several months/1 year - 70 - 80% strength

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List some differences between dogs and cats in regards to wound healing:

Generally speaking - cats heal weaker and you should leave their sutures in a little longer.
* Cats have lower cutaneous perfusion for the first week (by 2 weeks, no difference)
* Cats have a significantly lower wound breaking strength 1 week post-op
* Open wounds in cat heal largely by contraction whereas dogs heal largely by central “pull” of fibroblasts and epithelialization

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Which suture materials require 3-6 square knots for security (as apposed to 4-6)?

Polyglactin 910 (Vicryl)
Polyglytone (Caprosyn)
Nylon
Prolene

For size 3-0

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Define contamination, colonization and infection:

Contamination - The presence of microbes on a surface
Colonization - Surface microorganisms are replicating
Infection - Invasion and replication of microorganisms within the tissue

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What microbial burden has been associated with a higher rate of infection? What time does it typically take to reach this level?

10^5 CFU/g
Within 6 hours

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How does the production of granulation tissue differ between cats and dogs?

Open wounds in cats produce significantly less granulation tissue and are more likely to have a peripheral, rather than central, distribution of it

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At 21 days after wounding, how does epithelialization and total healing differ in dogs and cats?

Dogs: epithelialization 89%, total healing 98%
Cats: epithelialization 34%, total healing 84%

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What are some (8) potential causes of open wounds which fail to progress towards healing?

Systemic disease (uremia, hepatic disease, Diabetes, Cushings, FIV)
Malnutrition
Local tissue hypoxia and ischemia (Normovolemia must be maintained, blood transfusion if anemic)
Bacterial colonization
Altered cellular and stress response
Repetitive trauma
Presence of necrotic tissue
Tension

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What pressure is generally recommended for high pressure irrigation?
How is this best achieved?

16-22g needle onto a fluid administration set of a 1L bag of fluids under pressure of 300mmHg

Gives you 7-8 psi

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List some hydrophilic wound dressings:

Hydrogel
Hydrocolloid
Alginate

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List hyperosmotic wound dressings:

Hypertonic saline (20%)
Honey
Sugar

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What antimicrobial effects are provided by Honey?
What is the inhibin number of medical grade Honey?

Hydrogen peroxide production
Oxygen-derived free radicals
Phytochemicals (phenols and organic acids)
Acidic pH (3.2 - 4.5)

The inhibin number is the amount of dilution to which the honey will retain its antibacterial activity

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Other than is antimicrobial properties, what other effects of honey may enhance wound healing?

Reduction of inflammation due to anti-oxidant content
Stimulation of B- and T-lymphocyte proliferation
Stimulation of phagocytic activity
Stimulation of cytokine release from monocytes

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What is the underlying prinicple of moist wound healing?

Application of a hydrophilic (moisture retentive) dressing to maintain the cellular and cytokine-rich exudate at the wound surface
This facilitates debridement, granulation, and epithelialization

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How does incorporation of silver into alginate dressing effect its function?

Increased antimicrobial activity
Improved binding affinity for elastase, MMP-2, TNF-a, and IL-8
Further inhibited production of free radicals

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What is the recommended porosity of the foam and recommended pressures for negative pressure wound management in small animals?

400 - 600 um pore foam
Recommended -125mmHg for foam-based or -80mmHg for gauze based systems

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What are the purported benefits of negative pressure wound therapy?

Improve wound perfusion
Reduce edema
Stimulate granulation tissue formation
Decrease bacterial colonization
Remove exudate

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How may NPWT be beneficial for skin grafting? Used at what pressure?

Benefits:
- Stabilization of the graft
- Reduce fluid accumulation under the graft
- Prevent desiccation
- Possibly prevent bacterial contaminations

Pressure -65 to -75mmHg

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What is the mm of char that will penetrate skin in:
Monopolar
CO2
Radiowaves

Monopolar 0.255mm
CO2 0.215 mm
Radiowave 0.171 mm

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What percentage of all dogs presented for orthopedic problems are diagnosed with OCD?

What % of dogs presenting for ortho problems at under 1 year of age are diagnosed with OCD?

3.7% of ALL orthopedic dogs

9% of orthopedic dogs under 1 year.

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In most long bones, growth plates (physes) contribute ____% of final bone length whereas epiphyses contribute approximately ____%?

Growth plates contribute MOST 75-80% of final bone length (IMPORTANT)

Epiphyses contribute approx. 20-25%

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At what age does the medial aspect of humeral condyle (a center of ossification) fuse to the lateral condyle?

6 weeks

What are the (4) zones of the physis?

Resting (epiphyseal side) Proliferative Hypertrophic Mineralization

There is a grading scheme for OCD of the proximal humerus that grades from I to IV. What does a lesion of each type look like?

Type I: Cartilage surface normal, cartilage slightly thickened, miniscule subchondral bone defect Type II: Cartilage surface mottled, more thickened, small "cleft" of subchondral bone Type III: Discoid elevation of cartilage surface. Underlying bone sclerotic Type IV: Typically a partially or fully detached flap and joint mice

Describe the lesion of osteochondrosis latens?

Early, microscopic

Describe the lesion of Osteochondrosis manifesta?

Subclinical lesion that is both macroscopically and radiologically apparent.

The articular-epiphyseal complex, at the cartilaginous end of developing bone, has two layers. The inner layer is like a physis. The outer layer is immature cartilage and is avascular. It has four zones - what are they?

Superficial zone Transitional zone Radial zone (Tidemark) Zone of calcified cartilage

OCD is considered a polygenetic trait, but there is a strong breed and bloodline predisposition. What is the reported range of heritability of OCD (in %)?

10-45%

Most long bone growth in dogs occurs between what ages?

12-26 weeks of age (IMPORTANT)

What substances are involved in the local feed-back loop of chondrocyte proliferation?

- PTHrP - IHH (Indian hedgehog) - TGF-B Controls the irreversible differentiation of proliferative chondrocytes into hypertrophic chondrocytes. BMP, thyroid hormone and others are also needed for this phenotypic change to occur. (IMPORTANT)

What effect does growth hormone have on the resting zone of cartilage?

- Promotes differentiation into daughter cells capable of making Insulin-like growth factor 1 (IGF-1) which stimulates clonal expansion of chondrocytes. (IMPORTANT)

What percentage of its original strength will at tendon have at 6 weeks post repair?

56%

What percentage of its original strength will a tendon have 1 year after repair?

79%

Name the 3 stages of muscle strain (overstretching)?

- Stage 1: Myositis and bruising but architecture intact - Stage 2: Myositis and some tearing of fascial sheath - Stage 3: Tearing of fascial sheath, muscle fiber disruption and hematoma formation

What are the two types of tendons?

Paratenon lined (vascular) (gastroc, triceps insertions) sheathed tendons (avascular) (digital flexor tendons)

What occurs during the first 4-5 days after tendon repair? What needs to happen in the first 3 weeks, after 3 weeks?

The tendon ends lose holding power, then gradually increase over the next 2 weeks Sutures must entirely resist any gap formation for 3 weeks After 3 weeks, need normal loading for correct alignment of collagen as heals ***normal daily forces only require 25-33% of tendon capacity

What are the three overlapping stages of articular cartilage changes with OA?

1. Extracellular matrix degrades, water content increased, size of aggregan molecules decreased and structure of collagen network is damaged leading to reduced stiffness 2. Chondrocytes try to compensate through enhanced proliferation and metabolic activity. Cell clusters appear surrounded by newly synthesized matrix molecules. 3. Chondrocytes are no longer able to keep up, resulting in complete loss of cartilage tissue Phase 1/2 - thickness, swelling as proliferate -> phase 3 lose the battle and thins away

What inflammatory cytokines are known to upregulate the synthesis of matrix metalloproteases (MMPs) and other proteolytic enzymes?

IL-1 IL-17 IL-18 TNF-a *Synthesis of tissue inhibitors of metalloproteinases (TIMPS) are concomitantly decreased*

What role does nitrous oxide (NO) play in OA?

NO is a major catabolic factor produced by chondrocytes in response to proinflammatory cytokines IL-1b and TNF-a - Promotes chondrocyte apoptosis, most likely via mitochondrial dysfunction

What role does COX play in OA?

Chondrocytes from human OA cartilage explants express COX-2 and spontaneously produce PGE2 - PGE2 decreases proteoglycan synthesis and enhances degradation of aggrecan and Type II collagen - Upregulation of MMP-13, disintegrin and ADAMTS-5 - Downregulation of MMP-1

What enzymes can degrade the triple helix of Type II collagen?

MMP-1 and MMP-13 maybe MMP-8 and MMP-14

What is the most abundant noncollagenous protein in articular cartilage?

Cartilage oligomeric matrix protein

What growth factors can stimulate aggrecan and collagen synthesis?

IGF-1 IGF-2 TGF-b

What cell is a key cell in driving synovial control of cartilage metabolism?

Macrophages (through release of catabolic cytokines IL-1b and TNFa)

What are the expected cell counts and differential counts of normal synovial fluid, OA, rheumatoid, Nonerosive IMPA and Infective arthritis?

Normal joint: <2 x 10^9/L >94% mono OA joint: 2-5 x 10^9/L >88% mono Rheumatoid joint: 8-38 x 10^9/L 20-80% mono Nonerosive IMPA: 4-370 x 10^9/L 5-85% mono Infective arthritis: 40-267 x 10^9/L 1-10% monos (almost all neuts)

What are the most common bacteria in infective arthritis?

Dogs - Staph intermedius - Staph aureus - B-haemolytic Strep Cats - Pasteurella multocida - Bacteroides species

List the (5) main growth factors in relation to bone production:

Transforming growth factor-Beta (TGF-B) Bone morphogenic proteins (mostly BMP-2, -4, -7) Fibroblast growth factor Insulin-like growth factor Platelet-derived growth factor

What are the basic tenets of bone regeneration and grafting?

Osteogenesis: directly supplies and supports bone-forming cells Osteoinduction: capacity to induce bone formation when placed into a site where no bone formation will otherwise occur Osteoconduction: Provides a scaffold for mesenchymal stem cells and their progeny to migrate into and proliferate Osteopromotive: A material or physical impetus that results in enhancement of regenerating bone

What percentage of cells in autogenous cancellous bone graft survive at room temperature in normal saline for up to 3hr after harvesting? When does maximum osteogenesis from autogenous cancellous bone graft occur?

- 60% - Maximum osteogenesis at 8wk

Describe the healing process of an autogenous cancellous bone graft:

Minutes-hours: inflammatory response attracts lymphocytes, plasma cells, and mononuclear cells 5 days: Capillary loops enter 20 days: Necrotic tissue is resorbed and graft is fully vascularized - Woven bone initially placed which is remodeled over several months into lamellar bone - Remodeling of lamellar bone leads to corticalization - Remodeling of deeper trabecular bone leads to medulization

Which BMPs promote differentiation of mesenchymal stem cells to an osteoprogenitor lineage? Which promote differentiation of osteoprogenitor cells into osteoblastic cells?

- Differentiation into osteoprogenitor cells : BMP-2, -6, -9 - Differnetiation into osteoblastic cells: BMP-2, -4, -7, -9

What are IHC tumor makers for Mast cell tumors?

Ki-67, PCNA, CD117 (KIT)

What are IHC markers for histiocytic tumors

Lysozyme, CD18

What are IHC markers for melanoma/amelanotic melanoma

melanoma- Vimentin, Melanin A Amelanotic S-100, NSE (neuron specific enolase)

What are markers for GIST

CD117

What are IHC markers for B and T cell lymphoma

B= CD79 T= CD3

What rae IHC markers for Leiomyosarcoma

Desmin, Smooth muscle actin

What are IHC markers for carcinoma

Cytokeratin

What are IHC markers for sarcoma

Vimentin

Tidbits Flashcards

(62 cards)