Seminar - Caging Flashcards

1
Q

What are the two common stainless steel types? How do they differ? The addition of what element to which steel type reduces corrosion?

A

304 and 316, vary in the amount of chromium and nickel in the alloy. Molybdenum in 316 reduces corrision.

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2
Q

What factors vary in each type of caging polymer?

A

Resistance (to chemicals and heat), impact strength, cost

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3
Q

Describe polycarbonate caging.

A

Clear, rigid plastic with high impact strength. Autoclavable to 250 F. Cracked cages release BPA.

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4
Q

Describe hi-temp polycarbonate caging.

A

Clear with a slight tint. Similar to polycarbonate but autoclavable to 270 F.

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5
Q

Describe polysulfone/polyethersulfone caging.

A

Clear, right plastic with slight tint. High impact strength, autoclavable to 270 F.

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6
Q

Describe polyethylene terephthalate caging.

A

Used for disposable caging.

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7
Q

What is bisphenol A? Where is it found? Why is it released from these products? What does it mimic?

A

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.

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8
Q

How is polysulfone produced? What is generated as a breakdown product?

A

Produced by dimerization of BPA and diphenyl sulfone. Breakage of bonds produces BPS.

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9
Q

What cross-contamination risk does BPS pose? What risk to animals does it pose?

A

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.

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10
Q

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

A
  1. 20-26 C, 68-79 F
  2. 16-22 C, 61-72 F
  3. 18-29 C, 64-84 F
  4. 16-27 C, 61-81 F
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11
Q

What is the thermal neutral zone? What is the mouse and rat TNZ?

A

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

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12
Q

What were wire bottom cages suspended over litter trays w/o contact bedding previously used for? Why the shift away?

A

Toxicology. Foot lesions and rodent preference.

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13
Q

Who developed the static microisolater cage? When?

A

Robert Sedlacek in 1982

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14
Q

What are advantages and disadvantages of static microisolater cages?

A

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.

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15
Q

Where does most air exchange occur in a static microisolater cage?

A

At the cage-lid interface, not the filter.

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16
Q

How to improve poor microenvironment air quality?

A
  1. Change cages at sufficient density
  2. Reduce housing density
  3. Contact bedding with better performance
  4. Reduce room humidity
  5. Increase room temperature, reducing MiE relative humidity
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17
Q

When were IVCs developed?

A

Late 1980s, early 90s

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18
Q

How large is the filter on the top of an IVC?

A

0.2 microns

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19
Q

What is an enhanced containment IVC? What is a risk in power failure?

A

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.

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20
Q

What is the sound generation level of an IVC? Air speed?

A

Less than 50 dBA, no ultrasound emission. Air speed less than 0.2 m/sec

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21
Q

HEPA-filtered exhaust air or direct-ducted to room exhaust reduces what? (3)

A
  1. Exposure to allergens
  2. Bacterial contamination of MaE
  3. Room odor
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22
Q

What NH3, CO2, and intracage air speed measurements should be achieved?

A

NH3 < 50 ppm
CO2 < 5000 ppm
Intracage air speed < 50 lfpm

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23
Q

What gas sterilization methods can be used to sanitize rack units?

A

Vaporized hydrogen peroxide, chlorine dioxide, paraformaldehyde.

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24
Q

What is a risk of hazard containment rack cages?

A

Can explode!

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25
Q

What are the two type of Tecniplast ISOcages and their functions?

A

ISOCage N - high risk biocontainment.
ISOCage P - high bio-exclusion

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26
Q

What does CLAMS stand for?

A

Comprehensive Lab Animal Monitoring System

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27
Q

What are the features of a Mass Air Deplacement Unit (MADU)?

A

Unidirectional laminar flow, positive or negative. Do not protect operators

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28
Q

What type of air is used by MADUs?

A

Class 100 Air - No more than 100 particles 0.5 um or larger per cubic foot of air

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29
Q

What are features of a biosafety cabinet?

A

HEPA filtered with glass sash front opening. Provides product and personnel protection. Useful in high containment situations.

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30
Q

What are the three types of biological safety cabinets and their features?

A

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

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31
Q

What are the features of a changing station?

A

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.

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32
Q

What are general sanitation frequency for cages?

A

Enclosures and accessories, such as tops, sanitized at least once very 2 weeks. Solid-bottom cages, bottles, and sipper tubes at least weekly.

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33
Q

What was the old standard for cage wash cleaning?

A

180 F for 3 minutes. Kills vegetative bacteria in one second.

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34
Q

Does washing and sanitation require the use of chemicals? Why might chemicals be avoided?

A

No, can rely in heating and spray/agitation alone. Chemical residues can adversely affect animals and reduce stability and longevity of thermoplastics.

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35
Q

What compounds can potentially contaminate water? (5)

A

Pesticides, heavy metals, radionuclides, endocrine disrupters, pharmaceuticals

36
Q

Municipalities analyze their drinking water in compliance with which regulation, overseen by which agency? Which type of studies require routine periodic water analysis?

A

Safe Drinking Water Act, Environmental Protection Agency. GLP studies

37
Q

Water filtration excludes particles of what size?

A

> /= to 5 um. Activated carbon can be used to reduce contamination.

38
Q

Describe reverse osmosis filtration of water

A

Most common system when high quality water necessary. Flows through ultrafiltration membrane under pressure. Removes up to 99% of compounds. Filter may foul with organic matter, affecting efficiency and supporting bacterial growth. Membrane may scale which favors fouling with hard water.

39
Q

What are the two outcomes of UV filtration? What does the dosage depend on?

A

Disinfects water, reduce total organic carbon. Dosage depends on intensity and exposure time length.

40
Q

UV water uses what type of lamp? What wavelength of light?

A

Low-pressure mercury light. Bactericidal UV ray at 254 nm.

41
Q

When should UV lights be replaced? How should they be maintained?

A

Replace when emit light <30,000 uw-s/cm2. Clean class tubes regularly.

42
Q

How does ozone sanitize? What are the requirements for use?

A

Oxidizes microorganisms and organic contaminants. Requires an ozone generator and system to diffuse ozone into water.

43
Q

What does steam destory?

A

Vegetative bacteria, bacterial spores, fungi, and viruses.

44
Q

What does autoclaving destroy? What remains? How is this typically used?

A

Destroys microorganisms, endotoxins and other contaminants remain. Usually used for filled cage bottles.

45
Q

What additives are most frequently added to water? Why, and where at in the system?

A

Hydrochloric acid or chlorine. Reduce bacterial growth, especially when housing immune deficient strains. In a reservoir or in water distribution system.

46
Q

Water is acidified to what pH with hydrochloric acid? Why? Why not lower?

A

Acidified to 2.5 to 3.0. pH below 3.0 bactericidal to Pseudomonas aeruginosa and other Gm - bacteria. Lower than 2.0 results in reduced weight gain, water consumption, low splenic weight, and reduced bacterial species in gut.

47
Q

How does acidified water react with caging components? What products must be used and avoided?

A

Corrosive. Must use plastic polymers of type 316 stainless steel. SS w/o Mo (ie 304), copper, or brass will corrode.

48
Q

Is acidified water stable?

A

Temporally stable in noncorrosive container such as plastic carboy.

49
Q

What are two advantages of chloride addition?

A

Reduces bacterial and viral contamination, controls bacterial growth and biofilm accumulation in water distribution systems

50
Q

What is the additive to chlorinate water? What is the effective/active pH?

A

Sodium hypochlorite, pH 5-7

51
Q

What is the recommended concentration of chlorine? What is the safe level? What levels have been identified as ideal? Due to what pathogen?

A

0.5-10 ppm recommended. Safe < 10 ppm. Ideal 6-8 ppm in one study. Pseudomonas aeruginosa is among most chlorine-tolerant of enteric bacteria, can be cultured at 1 ppm.

52
Q

What happens to the chlorine concentration over time? Why? (3) What distribution system is this problematic for and why?

A

Dissipates over time with 3ppm decrease in concentration over 7 days. Off-gasses if it comes in contact with air, reacts with organic matter and other oxidizable contaminants, dissipates in water bottles. Problematic in water distribution systems coated with bacteria-generated biofilm - set proportioning system to deliver at least 2 ppm to furthest point.

53
Q

Why is water quality important for chlorination? (2)

A

RO water needs less chlorine due to lack of organic compounds, chlorination of water with organic compounds can generate by-produce trihalomethans, which can be cytotoxic, mutagenic, or carcinogenic.

54
Q

What must a sample be protected from prior to testing for chlorine?

A

Exposure to sun/UV light, agitation, or air

55
Q

How may chlorine by-products be present even without treatment by the facility?

A

Municipalities may chlorinate

56
Q

Chlorine at what concentrations is used for disinfection? Chlorine should not be added to water lower than what pH?

A

50 ppm. Do not add to water pH <5, will present as gas which can damage silicon seals in drinking water lixits.

57
Q

What can be one of the most time- and labor-intensive tasks?

A

Providing water to rodents

58
Q

What can occur in glass water bottles after autoclaving?

A

Silicone formation

59
Q

Silicone rubber stoppers are what color? Synthetic neoprene stoppers what color? What is an advantage of synthetic stoppers?

A

Black - rubber
Green - neoprene. More resistant to degradation by repeated autoclaving

60
Q

What is the function of a pressure reducing station?

A

Delivers water at low pressure, as low as 3 psi for rodents.

61
Q

Why are biofilms in automatic watering systems problematic? How can they be manged?

A

Biofilms protect bacteria from shear of high pressure flush and chemical additives. Manage by avoiding dead ends in system, flush rack tubing with sodium hypochlorite after cycling through rack washer, or autoclaving rack.

62
Q

Describe pelleted feed.

A

Most efficient with highest energy per unit and higher density. Involves heat and pressure which reduces bacterial and fungal loads

63
Q

Describe an extruded diet

A

Less dense, less hard

64
Q

What is an advantage and disadvantage of powdered diets?

A

Permits incorporation of additives, but tends to cake and get wasted.

65
Q

What ingredients do rodent diets primarily differ in? What percentage fat is used for breeding, gestation, and lactation? What is a disadvantage of high fat diets in breeding?

A

Protein and fat. 11% fat for breeding. Accumulation of intra-abdominal fat due to chronic use of high fat diet may shorten reproductive life span.

66
Q

What is a closed formula diet?

A

Individual components of diet and their proportions not specified. Guaranteed analysis provided. Permits changes in association with commodity prices. Most natural ingredient rodent diets.

67
Q

What is an open formula diet?

A

Have established known ingredient/percent by weight formulation.

68
Q

Name two specific phytoestrogens. What diet component are known to contain them?

A

Isoflavones diadzein and genistein. Protein sources such as soybean meal and alfalfa, replace with casein

69
Q

What are purified diets? What is an example?

A

Formulated from refined ingredients (granulated sugar, casein, etc.). AIN-76

70
Q

What are chemically defined diets? When are they typically used?

A

Formulated with chemically pure compounds. Utilized when altering a specific nutritional dietary component. Often used in germ free studies, low antigen studies. Expensive!

71
Q

Autoclaved diets are enriched with what nutrients? What other process may occur?

A

Enriched with thiamin, vitamin A and E, pantothenic acid, pyridoxine, and B12. May also be coated with silicon dioxide in soybean oil to reduce clumping and adherence due to pellet swelling with exposure to steam.

72
Q

What is a disadvantage of excessive sterilization on feed?

A

Depletes nutrients, cause pellets to become excessively hard as a result of polymerization of feed constituents.

73
Q

How are gamma-irradiated diets processed? What are two advantages? Are they sterile?

A

Subjected to 10 - 40 Kgrey (1-4 Mrad) from a cobalt source. Less processing after receipt, not subjected to effects of heat and moisture. Not truly sterile, bacterial fungal loads markedly reduced to less than 100 bacteria or fungi/gram of feed.

74
Q

How is irradiated diet typically packaged?

A

Smaller quantities (25 lb).

75
Q

Is irradiation effective against MPV?

A

Purported ineffective, but many institutions report elimination of seasonal recurrence of MPV.

76
Q

What are certified diets? Used by what studies? What contaminants are evaluated?

A

Analyzed and certified to contain no more than established levels of contaminants. Meet requirements of FDA’s GLP. Heavy metals, chlorinated hydrocarbons, organophosphates, aflatoxins.

77
Q

At what temperature and humidity are natural ingredient diets maintained? Specialty diets?

A

Natural: Temp <70, humidity <50%
Specialty: Temp 39-40F

78
Q

What does cool storage prevent?

A

Rancidity in which unsaturated fats and lipids are oxidized and converted into hydroperoxides, which break down into aldehydes, esters, alcohols, ketones, and hydrocarbons. Bad odor and taste.

79
Q

Most feeds have a shelf life of how long? Specialty diets? Why?

A

180 days, specialty diets often have 90 day shelf life if high in fat.

80
Q

List examples of hardwood and softwood. Which should be avoided? Why?

A

H: Aspen, beech, maple, birch
S: Pine or cedar
Avoid softwood, volatile amines alter hepatic microsomal enzyme concentrations.

81
Q

What size of corncob is available? What impact on microenvironment?

A

1/4 or 1/8 inch. Inhibits accumulation of NH3.

82
Q

What are disadvantages of corn cob? (5)

A
  1. Mold growth if not autoclaved or irradiated
  2. Abrasive
  3. Off-gassing of acetic acid from decay of organic matter
  4. Does not support nest building
  5. Mice may eat when fasted
83
Q

Describe cellulose bedding.

A

Processed wood/paper products. More expensive than hardwood, good nest building characteristics.

84
Q

What is Alpha-dri made from? Good for what studies?

A

Cellulose-fiber, dust free. Fasting or pain of feet or limbs.

85
Q

What type of bedding may be used on GLP studies? Why?

A

Certified bedding. Specific toxic environmental contaminants are measured to assure that they do not exceed max permissible concentrations.

86
Q

What are four advantages of environmental enrichment?

A

Reduce intermale aggression, stress, food consumption, and thermal stress

87
Q

Why should Neslets be avoided with nude mice?

A

Fibers can impact in conjunctival sac, causing conjunctivitis.