Seminar - Caging Flashcards
What are the two common stainless steel types? How do they differ? The addition of what element to which steel type reduces corrosion?
304 and 316, vary in the amount of chromium and nickel in the alloy. Molybdenum in 316 reduces corrision.
What factors vary in each type of caging polymer?
Resistance (to chemicals and heat), impact strength, cost
Describe polycarbonate caging.
Clear, rigid plastic with high impact strength. Autoclavable to 250 F. Cracked cages release BPA.
Describe hi-temp polycarbonate caging.
Clear with a slight tint. Similar to polycarbonate but autoclavable to 270 F.
Describe polysulfone/polyethersulfone caging.
Clear, right plastic with slight tint. High impact strength, autoclavable to 270 F.
Describe polyethylene terephthalate caging.
Used for disposable caging.
What is bisphenol A? Where is it found? Why is it released from these products? What does it mimic?
Constituent of some polymers (epoxies, polycarbonates, polysulfone). Release from polycarbonate cages and bottles, to lesser extend polysulfone components. Release as a un-poylmerized constituent or as a result of degradation secondary to hydrolysis at high temps or age-related release at room temp. Acts as an endocrine-disrupting chemical similar to 17B-estradiol.
How is polysulfone produced? What is generated as a breakdown product?
Produced by dimerization of BPA and diphenyl sulfone. Breakage of bonds produces BPS.
What cross-contamination risk does BPS pose? What risk to animals does it pose?
Released from damaged polysulfone cages and bottles. Cage washer water and internal surfaces can be contaminated, cross-contaminating intact cage surfaces. Acts as an endocrine-disrupting chemical similar to 17B estradiol.
What is the recommended dry bulb macroenvironmental temperatures for 1. Mice, rats, hamsters, gerbils, GP; 2. Rabbits; 3. Cats, dogs, nonhuman primates; 4. Farm animals, poultry
- 20-26 C, 68-79 F
- 16-22 C, 61-72 F
- 18-29 C, 64-84 F
- 16-27 C, 61-81 F
What is the thermal neutral zone? What is the mouse and rat TNZ?
Ambient temp range where thermoregulation occurs without the need to increase metabolic heat production or activate heat loss mechanisms.
Mouse = 26-34 C, 79-93 F
Rat = 26-30 C, 79-86 F
What were wire bottom cages suspended over litter trays w/o contact bedding previously used for? Why the shift away?
Toxicology. Foot lesions and rodent preference.
Who developed the static microisolater cage? When?
Robert Sedlacek in 1982
What are advantages and disadvantages of static microisolater cages?
A: Biocontainment, bioexclusion, chemical containment, containment of animal allergens.
D: Change in microenvironment (humidity and NH3) shortly after cage change. Air exchange rate markedly reduced compared to open cages.
Where does most air exchange occur in a static microisolater cage?
At the cage-lid interface, not the filter.
How to improve poor microenvironment air quality?
- Change cages at sufficient density
- Reduce housing density
- Contact bedding with better performance
- Reduce room humidity
- Increase room temperature, reducing MiE relative humidity
When were IVCs developed?
Late 1980s, early 90s
How large is the filter on the top of an IVC?
0.2 microns
What is an enhanced containment IVC? What is a risk in power failure?
Sealed with positive pressure, cage releases < 0.2 ng/m3 of allergens. If power out, animals only have 1 hour of oxygen. Unsealed cages have enough leakage.
What is the sound generation level of an IVC? Air speed?
Less than 50 dBA, no ultrasound emission. Air speed less than 0.2 m/sec
HEPA-filtered exhaust air or direct-ducted to room exhaust reduces what? (3)
- Exposure to allergens
- Bacterial contamination of MaE
- Room odor
What NH3, CO2, and intracage air speed measurements should be achieved?
NH3 < 50 ppm
CO2 < 5000 ppm
Intracage air speed < 50 lfpm
What gas sterilization methods can be used to sanitize rack units?
Vaporized hydrogen peroxide, chlorine dioxide, paraformaldehyde.
What is a risk of hazard containment rack cages?
Can explode!
What are the two type of Tecniplast ISOcages and their functions?
ISOCage N - high risk biocontainment.
ISOCage P - high bio-exclusion
What does CLAMS stand for?
Comprehensive Lab Animal Monitoring System
What are the features of a Mass Air Deplacement Unit (MADU)?
Unidirectional laminar flow, positive or negative. Do not protect operators
What type of air is used by MADUs?
Class 100 Air - No more than 100 particles 0.5 um or larger per cubic foot of air
What are features of a biosafety cabinet?
HEPA filtered with glass sash front opening. Provides product and personnel protection. Useful in high containment situations.
What are the three types of biological safety cabinets and their features?
Class I - No product protection, like laminar flow hood, no protection of animal, protection of user
Class II - Type A2 (70%), Type B1 (50%), Type B2 (0%) air recirculation
Class III - Enclosed cabinet, look like isolators
What are the features of a changing station?
HEPA filter above the work surface with product protection if sashes are positioned correctly. Much of air captured and is HEPA filtered below the work surface before release to room. Not suitable for use with hazards.
What are general sanitation frequency for cages?
Enclosures and accessories, such as tops, sanitized at least once very 2 weeks. Solid-bottom cages, bottles, and sipper tubes at least weekly.
What was the old standard for cage wash cleaning?
180 F for 3 minutes. Kills vegetative bacteria in one second.
Does washing and sanitation require the use of chemicals? Why might chemicals be avoided?
No, can rely in heating and spray/agitation alone. Chemical residues can adversely affect animals and reduce stability and longevity of thermoplastics.