Laboratory Animal Models

Question 1

First Veterinarian in laboratory medicine.

Answer 1

Dr. Simon Brimhall, VMD

Question 2

Role of Veterinarians in Biomedical Research

Answer 2

1. Provide Veterinary Care
2. Oversee Animal husbandry
3. Manage Animal Facilities and Breeding Colonies
4. Study laboratory animal diseases
5. Perform collaborative independent research

Question 3

Uses of toxicological testing

Answer 3

1. Pharmaceutical products
2. Agrochemical products
3. Veterinary drug
   -Safety in food animals
   -Safety assessment of residues

Question 4

3 “R”s

Answer 4

Replacement
Reduction
Refinement

Question 5

DA Administrative Order 40

Answer 5

Authority of BAI

Question 6

Species of choice in Reproductive toxicity testing

Answer 6

Rats and Mice

Question 7

Primarily used to determine hazard regarding the potential effect of prenatal exposure on the developing fetus

Answer 7

Developmental toxicity testing
Species of Choice: Rodents and Rabits

Question 8

Measurement of reproductive functional and structural defects in both sexes

Answer 8

Reproductive toxicity test

Question 9

Species of choice in cutaneous toxicity test

Answer 9

Albino rabbit and guinea pigs

Question 10

Asses potential acute local limitation and to evaluate acute subchronic and chronic systemic toxic effects

Answer 10

Cutaneous toxicity testing

Question 11

Species of choice in genotoxicity testing

Answer 11

Rodents

Question 12

Detect gene damage induced by the test compound

Answer 12

Genotoxicity testing

Question 13

Examine the possibility that a tested agent might cause tumors and other chemically related effects in one or more animal soecie

Answer 13

Carcinogenicity testing

Question 14

Detect adverse effects of xenobiotics on the immune system including all the relevant cells, organs and immune mechanisms

Answer 14

Immunotoxicity testing

Question 15

Chemical Injury MOA

Answer 15

Direct contact&raquo_space; Coagulate protein or damage cell membrane lipids

Question 16

Mercuric chloride poisoning MOA

Answer 16

Increased membrane permeability and inhibition of ion transport

Damage Kidney and GIT cells

Question 17

Necrosis of epithelial cells MOA

Answer 17

Affect key enzymes and metabolic intermediate of affected cells

Question 18

Mechanism of Oxalic Acid (Plant toxin)

Answer 18

Inhibit succinic dehydrogenase

Question 19

Mechanism of Fluoroacetate (Rodenticide)

Answer 19

Aconitase

Question 20

Toxicant in the inhibition of Oxidative Phosphorylation and its mechanism

Answer 20

Cyanides
Inhibition of enzymes containing iron, predominantly of cytochrome oxidase

Limited oxygen uptake
Low ATP production
- Fatigue
-Weakness

Question 21

Toxicants of Uncoupling Phosphorylation and its mechanism

Answer 21

Dinitriphenols
Chlorophenol
Arsenates

Increase oxygen utilization
Energy dissipated as heat
No ATP formation

-Fatigue
-Weakness
-Fever

Question 22

Plants that can cause Cyanide poisoning

Answer 22

Peach
Apricos
Arrowgras
Johnsongrass
Plum
Cherry
Almond
Elderberry

Question 23

Toxicants of inhibition nucleic acid and protein synthesis and its mechanism

Answer 23

Aflatoxin
Organimecurials
Amantin (Mushroom Toxin)

Combine with large or small ribosomal unit
Alkylation of DNA and inhibit replication/transcription

Question 24

MOA of Aflatoxin

Answer 24

Produced by Aspergillus flavus and A. parasiiticus

Inhibit transcription and translation

Question 25

"thiol poisons"

Answer 25

Organimercurials React with the -SH groups of proteins and they disturb the activity of proteins

Question 26

Example of organimercurials and its MOA

Answer 26

Methylmercury inhibit choline acetyl transferase ✓Signs and symptoms of motor dysfunction

Question 27

Carbon tetrachloride toxicity

Answer 27

Failure of the liver to transport triglyceride-rich low density lipoproteins into the plasma =accumulation of fats in the cells

Question 28

MOA of Strychnine

Answer 28

Antagonizes the inhibitory neurotransmitter glycine Strychnos nux-vomica

Question 29

MOA of DDT

Answer 29

Dichloro-diphenyl-trichloroethane Delay closing og Na+ channels and slowing opening K+ gates >> enhanced initiation of Action potentials >> increase seizure tendencies

Question 30

MOA of organophosphate insecticides

Answer 30

Inhibit acetylcholinesterase by bunding irreversibly to its esteric state

Question 31

Direct and indirect effect of neuronal necrosis

Answer 31

Direct: Organomecurials >> impairment of protein synthesis Indirect: Carbon monoxide or cyanide >> anoxia

Question 32

Toxicants in Demyelination and its MOA

Answer 32

Hexachlorophene Uncoupling of oxidative phosphorylation >> decreased Na+ K+ ATPase activity >> retention of water in myelin lamellae >> intramyelinic edema >> separation of myelin lamellae

Question 33

Toxicants in impaired axonal transport and its MOA

Answer 33

Vincristine Bind to tubulin >> inhibit microtubule formation >> disruption of fast axonal transport which relies on microtubules

Question 34

Hypoplasia and aplasia of cellular components of blood will lead to?

Answer 34

Direct toxic effect on bone marrow precursor cells

Question 35

MOA of nitrite and paracetamol poisoning

Answer 35

Fe in heme is oxidized >> methemoglobin >> incapable of reversible oxygenation >> decreased oxygen content of blood

Question 36

MOA of Carbon monoxide poisoning

Answer 36

CO competes with O2 >> carboxyhemoglobin>> cannot carry oxygen >> decreased oxygen content of the blood

Question 37

Any xenobiotic associated with adverse effects on development of male or female reproductive function.

Answer 37

Reproductive toxicants

Question 38

Cause of osteodystrophy due to excessive level of nutrients.

Answer 38

Dietary phosphorus stimulate PTH

Question 39

Effect of any synthetic or naturally occurring xenobiotic which can affect the endocrine system of exposed individuals

Answer 39

Endocrine disruption

Question 40

Immunotoxicants

Answer 40

✓Heavy Metals ✓Mycotoxins ✓Organophosphates

Question 41

Substances that induce birth defects

Answer 41

Teratogens ✓ Heavy Metals ✓ Antifungal drugs ✓ Nicotiana spp. - crooked calf disease in cattle

Question 42

Chemicals or its reactive metabolite causes a permanent change in the DNA of the target cell, such as mutation, a distortion of the DNA

Answer 42

Tumor initiators

Question 43

Influence the proliferation of initiated cells which results in the proliferation of preneoplastic cells

Answer 43

Tumor promoters

Question 44

T/F Initiator exposure followed by repeated promoter exposure will result tumor.

Answer 44

True

Question 45

T/F Repeated promoter exposure followed by initiator exposure will result tumor.

Answer 45

False