Midterm 1: Lectures 3-4 Flashcards
Disease
the manifestation of aberrant physiology
Pathogenesis
the mechanism of disease development
Pathology
examines relationship between change in structure and function to an underlysing disease
Who is the Father of modern pathology?
Rudolf Virchow
- described the life cycle of pork worm
Microscopy
apparatus that uses different lens to permit magnification
- resolution of 200nm
Resolution
ability to identify 2 points clearly
3 types of electron microscopy
- transmission: electron beam passed through tissue
- scanning: provides a 3D image
- scanning-transmission: highest detailed image
resolution of electron microscopy
1-200nm
immunohistochemistry
Lab method that uses antibodies to detect specific antigens in cell tissue
1) primary antibody binds to antigens on tissue
2) secondary antibody binds primary antibody and has an attached fluorochrome for detection
fluorescence microscopy
atoms on the fluorochrome emit longer detectable wavelength
confocal microscopy
- images have high resolution and multiple images can be generated into a 3D image
- provide real time images on living tissue
molecular pathology
- used in diagnostic pathology for tumour biology
- examines molecular composition of cells
small strand conformation polymorphism
- identifies small changes in genome
- an altered gene sequence has a change in the 3D structure of proteins which affects the proteins migration on PAGE gels
comparative genome hybridization
- testing for healthy vs tumor DNA
- can examine individual chromosomes or complete genome
- red flag = normal; blue flag = abnormal
- if we see a 50:50 ratio the DNA is normal
in-situ hybridization
identifies and localizes an abnormal cell within a tissue section
PCR
- amplification technique that amplifies undetectable amounts of RNA/DNA to detectable levels
- good to detect change in tumour genome and microbial pathogens
Tissue microarrays
1) multiple tissues put on slide and examined together for a single trait
2) a single tissue is examined using different diagnostic tests
2 streams of pathology in vet med
- anatomic pathologist
- clinical pathologist
Anatomic pathologist
examines structural change in tissues and organs to identify cause of disease
Clinical pathologist
examines change in blood and tissue biopsy to identify cause of disease
Infectious Thromboembolic Meningoencephalitis
Blood work reveals: leukopenia, neutropenia, degenerative left shift, normal serum
- caused by Hemophilus somnus
- septicemia and vasculitis
- blindness as key indicator
Fibrinopleuropneumonia
- caused by Hemophilis somnus
- problem in feedlots
- 90% fatality if not treated
Multicentric Bovine Lyphosarcoma
- ‘huffing puffing cow’
- problem in pedigree livestock and dairy herds
- retrovirus
- uncontrolled lymphocyte growth
Who performs necropsies in the farm setting?
- the general practitioner in the field
- done to determine cause of death and if the herd is at risk
Toxicosis
a diseased condition resulting from poisoning
Poison
substance that causes injury, illness, or death
Toxin
one of a number of poisons produced by certain plants, animals, and bacteria
Hyperkalemia
too much potassium becomes toxic
- cats
Toxic material
- common cause of non-infectious diseases in livestock
How are toxic materials classified? 5 categories
- classified by type of material or organism which produces the poison
1. Bacterial toxins
2. Metallic or chemical poisons
3. Zootoxins
4. Mycotoxins
5. Phytotoxins
Bacterial toxins
- endotoxin = part of the bacteria cell wall (LPS of gram -ve)
- exotoxin = released by bacteria into host
- antitoxin = neutralizes the toxin (ex. antibody)
Metallic/chemical toxins
metals interfere with the disulfide linkage enzymes present in mitochondria
Phytotoxins
- plant toxins
- largest group of potential poisons in livestock
- SILKY LUPIN = crooked calf syndrome; mom ingests plant and causes uterus not to move and stops kinesis
Zootoxins
- venom produced by animals
What type of zootoxin does the blue ring octopus produce?
- Maculotoxin
- similar to tetrodotoxin from puffer fish
Mycotoxins
- produced by mold or fungi and grow on grass, grain, peanuts, corn etc.
What are mycotoxins an antagonist to?
- vitamin K (needed to coagulate blood)
Clavicepi purpurea
- example of a mycotoxin
- ergotamine = vasoconstrictor, necrosis of digits, hallucinogenic
Cell injury
any change in the cell that has lost its ability to maintain the normal or adaptive homeostatic state
2 types of cell injury
- reversible cell injury (degeneration)
- irreversible cell injury
5 mechanisms for cell death
- ATP depletion
- Oxygen free radicals
- Increased intracellular calcium
- Membrane permeability defects
- Irreversible mitochondrial damage
ATP depletion
- needed to power synthetic and degradative cell processes
- produced by: oxidative phosphorylation (aerobic) and glycolytic pathways (anaerobic)
Oxygen free radicals
- biproduct of aerobic metabolism (oxidative phosphorylation
- they are missing an electron and will damage lipids, proteins, and nucleic acids to get one
- cell has a free-radical scavenging system but if the radicals overwhelm the system, damage occurs
Increased intracellular Ca2+ (loss of Ca2+ homeostatic mechanism)
Calcium aka The Cell Assassin
- will activate phospholipidase, protease, ATPase, and endonuclease
- usually pumps ensure excess calcium is returned to the extracellular matric or sequestered in the mitochondria and ER
Membrane permeability defects
- loss of selective membrane permeability; ions flood cell
- ions cause H2O to follow and cause swelling
Irreversible mitochondrial damage
- mammalian cells are dependent on oxidative metabolism
Selenosis
- selenium toxicity
- Se is essential to animals but too much is a problem
Who is most susceptible to selenosis?
swine>horses>cattle>sheep
What will Se replace in proteins?
- very similar to sulfur
- affects disulfide linkages, tertiary & quaternary structures, and enzyme activity
- narrow range btw Se deficiency and toxicity
How do animals ingest too much Se?
- pyritic Se goes into soil and forms selenite and selenate both of which are water soluble
- animals orally uptake H2O, eat plants rich in Se, or are over-supplemented
What are 6 clinical signs of acute selenosis?
- laboured breathing
- abdominal pain and bruxism
- no appetite, vomiting, diarrhea
- garlic breath
- drop in blood pressure
- death
Polymyelomalacia
- selenosis unique to swine
- wasting of the gray matter of the spinal cord = motor neurons shut down paralyzing the animal
- animal is still 100% mentally aware
Chronic selenosis
- aka alkali disease
- > 30 days of Se exposure
- alopecia and dystrophic hoof growth
- swelling, pain, lame
