BB Ch29 - Factors that may affect research Flashcards
- From what parental stock are SHR and WKY rats derived and does this make them homozygous?
Wistar; no, they are actually heterogeneic and some sources of WKY are outbred stocks.
- Why are neonates more sensitive to carcinogenic compounds?
Because of hepatic microsomal enzyme immaturity which limits the ability to biotransform xenobiotics.
- Why might older animals have a greater likelihood of xenobiotic toxicity?
Decreased enzyme activity, decreased hepatic and renal blood flow, smaller livers, increased body fat, decreased excretory capability.
- What was a striking difference between two strains of senescence-accelerated mice (SAM) as they aged?
SAMP1 had increased blood pressure, SAMP8 had decreased blood pressure.
- Which gender of rats has a reduced capacity to biotransform certain chemicals and therefore remains anesthetized long with hexobarbital and parathion?
females
- Which mouse gender is more susceptible to chloroform toxicity and why?
Males, because the renal conversion of chlorform to phosgene occurs 10x faster in males vs females.
- What type of immune response predominates in CBA/J mice?
TH1 or cell mediated.
- What type of immune response predominates in BALB/c mice?
TH2 or humoral.
- Which response is effective against murine leukemia virus?
TH1 response that B10.BR mice generate.
- Which response is effective against helminths?
TH2 response that BALB.K mice generate.
- What dietary conditions may alter the biotransformation of xenobiotics?
Mineral, vitamin, protein deficiencies, lipid composition.
- How will the deficiency or excess of testosterone affect cytochrome P450 enzyme activity?
Deficiency of testosterone decreases the ability to biotransform xenobiotics and excess testosterone increases the ability to biotransform xenobiotics.
- Define the thermoneutral zone.
The temperature range in which homeotherms exert minimal energy to maintain core body temperature.
- When the temperature rises does toxicity of amphetamine or ephedrine increase?
Amphetamine increases while ephedrine decreases
- Name some effects of increased environmental temperature in rodents.
. Drug toxicity; death; testicular atrophy; decreased milk quantity and tail/ear/paw/salivary gland size.
- Low temperature affects what biologic parameters in rodents?
Growth rate, litter size, neonate viability.
- How does high relative humidity affect research?
Impacts thermoregulation, decreased activity for mice, enhancement of Sendai virus transmission, decreased influenza transmission, higher microenvironment ammonia levels, alters skin absorption of various substances.
- How does low humidity affect research?
Increased mouse activity, delayed sexual maturity, ringtail
- The quality of microenvironmental air is influenced by what?
The caging system, the strain or stock of animal, bedding utilized, housing density, macroenvironmental conditions
- What are some drawbacks to static isolation caging systems?
Significantly impede air exchange, accumulate gaseous pollutants (NH3 and CO2)
- What does the acronym ACGIH stand for?
American Conference of Governmental Industrial Hygienists
- The ACGIH set an average NH3 concentration of 25 ppm for an 8 hour time period. Housing the maximum number of mice in static isolator caging for 7 days can bring NH3 levels how high?
350 ppm ( a 14 fold increase)
- What are some pathological changes induced by the respiratory irritant NH3?
Decreased cilia numbers of the respiratory epithelium, hyperplasia of respiratory epithelium, glandular crypt formation in respiratory and olfactory epithelium
- What effect might NH3 have on the eyes of inbred and F1 mouse strains?
Corneal opacities due to inhibition of hepatic microsomal enzyme system components
- What are the ACGIH exposure limits for CO2 in ppm for 8 hours?
5,000 ppm
- Name some volatile chemicals that have the potential to influence the air animals breathe?
Aromatic hydrocarbons from cedar and pine bedding, pesticides, odorants, electrically charged HVAC generated airborne particles
- The human ear is most sensitive to sounds at what KHz?
2 KHz
- Peak auditory sensitivities of rodents in KHz?
30-60 KHz
- List some effects of low frequency sounds (< 20 KHz) on rodents?
Alter H20 consumption, blood pressure, blood corticosteroids, glucose, insulin concentrations, reproductive performance, body weight, eosinophil count, tumor resistance, learning ability, adrenal and cardiac hypertrophy
- Name some effects of ultrasound on rodents.
Decreased fertility and productivity, causes diuresis, induces audiogenic seizures, decreased locomotor activity, destroys auditory structures in rodents, prenatal development interference
- Which strains of mice are genetically susceptible to audiogenic seizures?
AKR, BALB/c, CBA, C57, DBA/2
- List some of the ways light influences reproductive physiology.
Anestrus duration, vaginal opening time, ovarian and uterine weights, estrous cycle length, preweaning mortality
- In addition to light intensity and albinism, what other variables affect extent of photoreceptor damage?
Light intensity, body temperature, nocturnality, light levels under which animals were raised, age, hormone status, time of day during light exposure
- What is the current recommendation for cage-level illumination according to the Guide?
130-325 lux unless animals were raised at very low light levels
- Continuous illumination as low as __ for 7-10 days can damage photoreceptor cells in rats.
110 lux
- What is the basic physiologic process that drives photoperiodicity?
Retinal photoreceptors stimulate neuroendocrine pathways and release hypothalamic hormones, including gonadotropins
- What are the two main lab animal species that are very sensitive to photoperiod changes?
Hamster and squirrel monkey
- What are some adverse effects of continuous illumination in rodents?
. Cycling cessation, permanent vaginal cornification, excess ovarian follicle development
- What are the two principal forms of radiation?
Electromagnetic and ionizing
- Give examples of each type of radiation.
Electromagnetic: uv, visible, infrared light, microwaves, radiowaves; Ionizing: gamma rays, x rays, atomic particles (alpha and beta)
- What are some negative effects of UVB radiation?
Ocular damage, immunosuppression (which can negatively affect cancer & infectious disease)
- List some adverse effects of ionizing radiation.
DNA damage can result in genetic, teratogenic, and somatic effects
- What are 3 factors that may be altered when rats are housed in cages with metal or plastic floors?
Metabolic rate, evaporative water loss, colon temperatures
- What are some problems with ventilated caging?
Chilling, dehydration, pheromone dilution, breeding alterations
- Give a definition of xenobiotics.
LAM definition: Chemicals or compounds that are foreign to a biological system. On-line medical dictionary definition: A completely synthetic chemical compound, which does not naturally occur on earth and thus believed to be resistant to environmental degradation.
- Biotransformation of xenobiotics (aflatoxins, heavy metals, insecticides, anesthetic agents) are affected by what host factors?
Species, strain, age, sex, exposure time, enzymes, nutritional and disease status, environmental factors
- What is the principal source of xenobiotic compound exposure?
diet
- Cat breeding colonies have increased or decreased reproductive efficiency when dietary fat was increased from 15 to 27%?
increased
- List some benefits of dietary restriction.
Resisting effects of aging, degeneration, infectious disease, neoplasms; beneficial effect on endocrine system and cell-cycling rate.
- Name some drinking water contaminants found world-wide.
Pesticides, heavy metals, radionuclides, antibiotics, analgesics, antiseptics, beta-blockers, cholesterol-lowering drugs
What effects can be induced by chlorine treatment of drinking water to minimize microbial contaminants?
it may cause alterations in immune response and may be carcinogenic and mutagenic
- Name some problems with drinking water acidification:
Decreased weight gain, water consumption, numbers of ileal bacteria (with more pronounced effects in immunosuppressed mice)
- True or False: Anesthetics may be directly toxic.
True
- Which organ system does methoxyflurane affect in F344 rats?
urinary
- Which local anesthetic is associated with methemoglobinemia in several species when sprayed on mucus membranes?
benzocaine
- Which opioid is attributed to pica in rats?
Buprenorphine
- Which euthanasia methods are associated with mitogen-induced lymphoproliferation?
CO2, halothane overdose, cervical dislocation with or without anesthetic
- Which euthanasia method has been shown to cause dramatic increases in plasma catecholamine concentrations?
Decapitation
- Which euthanasia method is known to cause acidosis, decreased cerebral sodium and potassium concentrations, and lung petechiation?
CO2 inhalation
- Which euthanasia method is used by neuroscientists in order to fix brain neurochemicals and metabolites and maintain the brain’s anatomic integrity because the other methods are unsuitable?
Microwave irradiation
- What is the condition that often occurs in guinea pigs, hamsters, gerbils, and rabbit that may develop after antibiotic administration?
Enterotoxemia
- Which toxin-producing bacteria are usually affiliated with the cecal dysbiosis?
Clostridium difficile and Clostridium spiroforme
- What ingredient that is often used in penicillin, is toxic to guinea pigs, mice, and rabbits?
Procaine
- Name the organ systems affected by aminoglycosides:
Urinary, auditory, cardiac, immune
- Which anthelmintic is capable of stimulating cell-mediated immune responses, enhancing the rate of T-cell differentiation, and increasing the activity of effector lymphocytes?
Levamisole
- The lack of what components are factors in ivermectin toxicity of certain mice?
Drug transporting P-glucoproteins
- Which mammalian structure in the brain is responsible for detecting pheromones?
Vomeronasal organ
- How might a stressed rat release alarm chemosignals for inhibitory or stimulatory purposes?
From body surface into air or via urine
- Which is considered to be the most important and common viral pathogen of mice?
MHV
- Does MHV stimulate or suppress the immune system?
both
- Besides affecting the respiratory system, which arm of the immune system does Sendai virus alter in rats and mice?
Both humoral and cell mediated
- Which virus is an important zoonotic pathogen, as well as a common contaminant of transplantable tumors, cell lines, and biological materials?
Lymphocytic choriomeningitis virus (LCMV)
- What well-known rat virus may potentially interfere with research involving lacrimal and salivary glands, respiratory system, and neonatal development?
SDAV sialodacryoadenitis virus
- What is the hallmark of lactate dehydrogenase elevating enzyme virus?
Elevation of one isozyme of LDV due to reduced clearance
T or F: LCM is shed for approximately two weeks post-infection?
False - lifelong viral shedding
- Which bacterium alters the cytokinetics of colonic muscosal epithelium?
Citrobacter rodentium
- Which pathogen induces hepatic neoplasia: Helicobacter hepaticus or H. bilis?
H. hepaticus
- Which adhesion molecule is expressed as a result of infection with Pasteurella multocida?
VCAM-1
- Which fungus is not uncommon in immunocompromised lab animals?
Pneumocystis carinii
- Trichosomoides crassicauda causes what type of cellular change in the urinary bladder of rats?
Hyperplasia or papillomatosis
