Important Pathogeneses Flashcards
The virulence factor responsible for this lesion is?
a. leukotoxin
b. Shiga toxin
c. Lipopolysaccharide
d. Lipo-oligo saccharide
D. Lipo-oligosaccharide is the main virulence factor responsible for the lesion of TME as a result of Histophilus somni infection in ruminants. The factor targets endothelial cell apoptosis via caspase-3 activation leading to exposure of subendothelial collagen, vasculitis and a secondary thombus formation. Leukotoxin is found in Mannheimia hemolytica infections and is responsible for oat cell formation. Shiga toxin is the main factor found in Shigella in non-human primates, and LPS is found in all Gram negative bacteria.
This lesion can be the result of all of the following except:
A. Lead toxicity
B. Salt toxicity
C. Bracken fern ingestion
D. Crotalaria ingestion
D. Crotalaria is a PA toxicity producing plant with typical hepatic lesions. Lead, salt and bracken fern can all produce polioencephalomalacia which autoflouresces under UV light. Bracken fern is a thiaminase-producing plant leading to thiamine deficiency, one of the main causes of polio.
Spider lamb syndrome is due to a point mutation in which gene?
A. SLC4A2
B. FGFR3
C. SLC13A1
D. ACAN
B. Fibroblast growth factor receptor 3 leads to decreased inhitibion of chondrocytes entering hypertrophic phase and increased length of long bones with multiple ossication centers. It is normally expressed by resting chondrocytes to prevent excessive chondrycyte proliferation. SLC4A2 is the defective gene in congenital osteopetrosis. SLC13A1 mutation causes congenital dwarfsm in Texel sheep. ACAN mutation causes bulldog-type chondrodysplasia in cattle (disproportionate dwarfism).
The predominant type of collagen found in bone is:
A. Type I collagen
B. Type II colllagen
C. Type III collagen
D. Type IV collagen
A. Type I collagen is the predominant collagen in bone, dentin, ligaments, tendons and ocular sclera. Type II collage is found in growth plates. Type IV collagen is found in skin.
Vitamin C is required for which step of collagen formation?
A. synthesis on rough ER
B. enzymatic cleavage through hydroxylation of proline and lysine
C. alignment of pro-collagen chains to form triple helix
D. cleavage in extracellular spaces
E. cross-linking to stabilize collagen and give it tensile strength
B. enzymatic cleavage through hydroxylation of proline and lysine
Osteogenesis imperfecta results in what type of deficiency in Type I collagen?
A. Quantitative
B. Qualitative
C. Quantitative and qualitative
C. Quantitative and qualitative deficiency in collagen in osteogenesis imperfecta results from mutated COL1A1 and COL1A2 genes that code for the alpha 1 and alpha 2 procollagen molecules.
Tissue from an ox. Sufur granules associated with the gross lesion of this image (Gram negative coccobacilli colonies encircled by Splendore-Hoeppeli material) are indicative of what organism?
A. Actinomyces bovis
B. Actinobacillus pleuropneumoniae
C. Actinobacillus lignieresii
D. Nocardia spp.
This image is from wodden tongue caused by Actinobacillus lignieresii, part of YAACSS. Sulfur granules are found in the center of pyogranulomas within the tongue in typical wooden tongue and in lymphatics in atypical wooden tongue. A. bovis is gram positive. A. pleuropneumonia is the cause of porcine contagious pleuropneumonia in pigs. Nocardia is a Gram positive filamentous bacteria.
Salmonella uses all of the following virulence factors except:
A. Fimbriae
B. Flagella
C. Secretion system encoded on pathogenicity islands
D. Salmonella-containing vacuole
E. Leukotoxin
E. Salmonella does not use leukotoxins in its pathogenesis. Actually, Salmonella uses leukocyte trafficking to disseminate throughout the body. Endotoxins are produced by Salmonella to induce vasculitis. Enterotoxins are produced by E. coli and Vibrio cholerae. Salmonella are motile using their flagella, attach to enterocyte/M cell surfaces via their fimbriae, and use a T3SS encoded on SPI-2 to survive in its Salmonella-containing vauole within macrophages. T3SS is also encoded by SPI-1 to invade nonphagocytic cells.
Fibrous osteodystrophy in reptiles
Inadequate vitamin D from inadequate wavelength of light –> decreased activation of vitamin D –> decreased absorption of Calcium from diet –> activation of hyperparathyroidism/parathyroid hyperplasia –> activation of osteclasts to resorb Ca from bone –> replacement of mineralized bone with fibrous connective tissue.
Fibrous osteodystrophy in older cats and dogs.
CKD –> retention of phosphorus from decreased GFR –> phosphorus increases in blood –> increased serum fibroblast growth factor 23 (FGF23)–> depresses renal 1-α-hydroxylase (decreased synthesis of calcitriol/active vitamin D)–> decreased circulating levels of calcitriol results in chief cell hyperplasia and hypocalcemia > increased parathyroid hormone causes osteoclastic bone resorption to increase calcium levels in blood via activation of RANKL –> replacement of bone with fibrous connective tissue (bone marrow stromal cells differentiate into fibroblasts), usually in mandibles and maxilla
What is the mechanism of atherosclerosis from hypothyroidism in dogs?
Decreased activation of lipoprotein lipase
What does a mutation in fibroblast growth factor 4 cause?
chondrodystrophy in dogs
What does a mutation in fibroblast growth factor 3 cause?
spider lamb disease
SLC2A9 gene mutation causes what?
hyperuricosemia in the Dalmation dog; produce too much uric acid, precipitates in alkaine urine into ammonium biurate stones ; also occurs in PSS and English bulldogs
ECA10 (this stands for Equine chromosome 10 NOT a gene) gene mutation causes?
osteochondrosis in horses
