Journal of the American Association for Laboratory Animal Science
Volume 51, Number 5, September 2012
ORIGINAL RESEARCH
Husbandry
Hurst and Litwak. Accelerative Forces Associated with Routine Inhouse Transportation of Rodent Cages, pp. 544-547
Domain 3
SUMMARY: Transportation of rodents for even small periods of time can affect research endpoints. This study used a rodent sized 24 g accelerometer inside a mouse cage to measure accelerative and decelerative forces associated with cage transport on a plastic cart, small or large metal cart, or by hand, and the effect of placing either a towel or pad between the cage and the cart. Surprisingly, the plastic cart was associated with highest acceleration forces, and hand carrying one of the lowest (n.b. the carrying was done with special attention to not moving the cage in the x-y axis at all, which is not standard for hand carrying). The best method for ameliorating the accelerative forces was the use of the towel between the cage and the cart. The route used to measure acceleration in the cage included changes in flooring type, starting and stopping, and going over the threshold of an elevator. The threshold bump produced the greatest peaks in acceleration in all cart types. The authors also discovered that housing methods did not expose the cage to acceleration, but low levels of vibration, and that motion of the cage correlated with cart type – large metal cart having the lowest acceleration of the cart types, perhaps due to hollow tube struts and spot welded shelves, that might decrease vibration transmitted to the cage.
QUESTIONS
1. What obstacle produced greatest accelerative forces within the cage on all cart types?
a. Changing floor types
b. Picking up the cage to put it on the cart
c. Entering an elevator
d. Moving the rack the cages were on
2. What was the best method of decreasing accelerative forces?
a. Padding with a towel
b. Padding with a cotton pad
c. Using a metal cart
d. Hand carrying
ANSWERS
1. c
2. a
Costa et al. Handling of Adolescent Rats Improves Learning and Memory and Decreases Anxiety, pp. 548-554
Domain 3: Research; T3. Design and Conduct Research
Domain 4: Animal Care; T1 K11. Environmental Causes and Effects on Research
Primary Species: Rat (Rattus norvegicus)
SUMMARY: The investigators were interested in examining the effects of adolescent rat’s adaptation to handling on experimental procedures and experimental outcomes. In particular they were concerned with combining behavioral responses to anxiety tests with stress hormone concentrations. Extensive evidence exists to show that handling of neonatal animals results in changes in anxiety, cognition, and fear responses, altered physiological parameters, and changes in plasticity of the CNS. Studies exist for adolescent and adult animals that show the changes in behavioral responses to anxiety-related test but none have combined behavioral studies with stress hormone concentrations of the animals. In this study, they promote the use of the Elevated Plus Maze (EPM) for examining behaviors as it allows for the evaluation of not only anxiety but also cognition behaviors. The rationale given for this is that transfer latency (movement from open arms to closed arms) can be used as a measure of learning and memory.
In the experiments 24 (n=12 handled and n=12 control) male Sprague-Dawley rats, 60 days old when the experiments began. Rats were handled for 5 minutes per day by placing the animal on the experimenters lap or on a tabletop and stroking its neck and back. This continued 5 days per week for 6 weeks. Control animals were left undisturbed for the same time period. Animals were evaluated 2 days after the last handling session in the EPM test. For testing anxiety and fear, the percentage of time spent in the open arms and latency to first open arm entry were examined. The number of closed arm entries was used as a measure of general motor activity and the percentage of open arm entries was used as a mixed index of anxiety and general motor activity. Cognitive measures in the EPM were measured 48 hours later by recording latency from the enclosed arm which would indicate learning and this was repeated 24 hours later to measure retention. Blood collection took place one week post- behavioral tests after decapitation without anesthesia. Catecholamines and corticosterone were analyzed for.
Compared with the control group, handled rats showed increases in the percentage of time spent in the open arms, the percentage of entries into the open arms, and the number of entries into the open arms all of which indicate decreased anxiety. General locomotion was not affected. These animals also showed decreases in the latency of the first open arm entry in the second round of testing indicating improved learning. This was reflected in the second trial of testing escape latency and possibly involved improved memory however the evidence for this is questionable. These findings were consistent with previous studies in variably aged animals. Plasma norepinephrine was significantly lower in the handled group but no differences were found for epinephrine or corticosterone. The authors suggest that this could be a reflection of decreased anxiety due to decreased basal activity of sympathetic nerves.
In their conclusion, the authors offer this study as evidence that the effects of handling are not restricted to neonatal periods. Handling should be considered a positive experience in adolescent rats and is valid as a form of environmental enrichment.
QUESTIONS
1. Handling of rats improves has been found to diminish anxiety when implemented:
a. During Neonatal Periods
b. During Adolescence
c. During Adulthood
d. All of the above
2. Elevated Plus Maze can be used in rats for the study alternations of:
a. Anxiety
b. Food motivation
c. Learning
d. Memory
e. All of the above
f. A, C and D
3. Anxiolytic effect in adolescent rats can be produced with:
a. 5-minutes of handling per day, 5 days per week
b. 20-minutes of handling per day, 5 days per week
c. One hour of handling per day, 5 days per week
d. 20 minutes of handling per day, once per week
ANSWERS
1. d
2. f
3. a
Management
Glueck et al. Exposure of Laboratory Animal Care Workers to Airborne Mouse and Rat Allergens, pp. 554-560
Domains 5: Regulatory Responsibilities; T3: Provide advice to OHS programs, K5: OHS
Primary Species: Mouse (Mus musculus) and Rat (Rattus norvegicus)
SUMMARY: Urine of rats and mice is the main source of allergenic proteins that can enter the respiratory tract of laboratory animal care workers. The proteins from urine can become aerosolized allowing entry into the respiratory tract of workers and this may explain why Laboratory Animal Allergy (LAA) is a common occupational hazard for workers exposed to laboratory animals. Little is known about the levels and determinants of these exposures in the United States. This study investigated differences between activities in animal facilities and levels of personal exposure to allergen by collecting personal breathing zone dust samples from caretakers during full workdays. Mice and rat urinary allergens in inhalable dust were quantified via immunoassay. The activities of the sampled workers were observed, and the methods of preventing exposure to allergens were recorded. Washing and cleaning cages and the number of mice handled daily were the most important determinants of personal exposure to mouse urinary allergen, whereas those with lower exposures were tasks in the animals rooms that did involve major animal movements. There was a positive relationship between increased allergen exposure and working with a greater number of rodents. Personal exposures to mouse urinary allergen were associated with day-to-day variation of tasks rather than characteristics of workers. Only persons who handled rats were exposed to rat urinary allergen. The current findings are valuable for establishing exposure levels against which comparisons of improvement or deterioration of personal exposures can be made.
QUESTIONS
1. Name the protein product of the mouse Mup17 gene that accounts for much of the allergenic properties of mouse urine.
2. Exposure and sensitization to rodent Mup proteins is a leading cause of what occupational disease of laboratory animal care workers and scientists?
3. Workers involved in which of the following activities experience the greatest exposure to rodent allergens? Select all that apply.
a. Daily health checks without opening cages
b. Dry cage cleaning
c. Washing cages
d. Transferring animals between cages during cage change outs
ANSWERS
1. Mus m 1, Ag1, or MA1 – all names for the same gene product
2. Laboratory Animal Allergy (LAA)
3. b & d – tasks associated with the highest rate of exposure were cleaning cages and handling of animals; washing cages, which is presumably a wet process that entails dust suppression, was associated with much lower exposures than cleaning
Weigler et al. Risk-Based Immunization Policies and Tuberculosis Screening Practices for Animal Care and Research Workers in the United States: Survey Results and Recommendations, pp. 561-572
Domain 5: Regulatory Responsibilities; T3. Provide advice to occupational health and safety programs
SUMMARY: Occupational health and safety is especially important for laboratory animal and research workers (ACRW) due to the increased exposure to animals that may carry zoonotic disease and the use of infectious disease agents in research. As with any place of employment, the United Sates Occupational Safety and Health Act requires that the employer ensure a safe working environment without recognizable hazards. A variety of individuals and committees have responsibility for assessment of risk in laboratory animal facilities including laboratory directors, principal investigators, Institutional Biosafety Committees, IACUC, biologic safety professionals, and laboratory animal veterinarians. It had been previously shown that there is a low rate of zoonotic disease in ACRW and the authors sought to describe the preventive practices that may have led to this success.
The authors have conducted a web-based survey of all veterinarians working in laboratory animal facilities in the United States. The survey consisted of 70 logic based questions allowing multiple answers and was first tested on a small group of OHS professionals (n=5). The majority of veterinarians worked in academic institutions, pharmaceutical or biotechnology companies. Most institutions reported using rodents or rabbits with 51.9% using non-human primates. All institutions maintained an OHS program and more than 90% enrolled husbandry staff, veterinarians, veterinary technicians and research investigators. The majority also enrolled maintenance workers, IACUC members, graduate and undergraduate students. Most OHS programs were located in the same building. OHS consisted of health questionnaires, animal species exposure assessment and immunizations with annual re-evaluation. Only a few institutions stored serum. All institutions that housed NHP's had a TB screening program
including purified protein derivative (PPD) intradermal skin tests and symptom questionnaires. Other modalities included the interferon-gamma release assay (IGRA) or chest radiographs. Typical immunizations included tetanus, hepatitis B, influenza, rabies and measles. Note that there are no licensed vaccines available for B virus, Q fever, Chlamydophila, Pasteurella or Orf.
Overall, they found that OHS programs are well-designed and thorough at the institutions of the respondents representing 65% of those contacted.
QUESTIONS
1. In the United States, what regulation requires that places of employment be free from recognizable hazards?
2. The IGRA:
a. Detects antibodies to Mycobacterium tuberculosis
b. Tests for response of leukocytes to M. tuberculosis
c. Requires two visits to OHS
d. Can be performed on serum
3. There are major deficiencies in OHS programs in laboratory animal facilities in the USA. T/F
4. According to this survey, the most commonly administered vaccine as part of an OHS program is:
a. Rabies
b. Influenza
c. Tetanus
d. Hepatitis B
e. Measles
ANSWERS
1. Occupational Health and Safety Act
2. b
3. F
4. c
Health Surveillance
Weiss et al. Comparison of a Fur Mite PCR Assay and the Tape Test for Initial and Posttreatment Diagnosis during a Natural Infection, pp. 574-578
Domain 1; Task 3
Primary Species: Mouse (Mus musculus)
SUMMARY: Effectiveness of the tape test and PCR assay were compared in a small population of mice at the onset of diagnosis (day 1) and during treatment at 6 wk and 12 wk. Mice were treated by placing cotton balls impregnated with Mitarrest (7.4% permethrin) in the cage once weekly for 6 weeks. PCR was performed by passing a sterile polyester swab multiple times against the grain of the fur over the dorsum, head, abdomen, and inguinal region. It was hypothesized that the PCR assay would be a more sensitive indicator than microscopic tape impression examination after treatment compared with initial diagnosis.
Results showed that PCR is a reliable diagnostic method during active fur mite infection (sensitivity 100% before treatment) but false-negative results are possible after treatment.
Therefore, negative PCR results should be interpreted carefully if mites are still suspected, and a secondary diagnostic method should be considered.
Side Note: Efficacy of treatment was not calculated – several samples remained both PCR and tape test positive after treatment.
QUESTIONS
1. How many days does it take Myobia musculi to complete a life cycle of fur-bound egg to motile nymph to reproductively mature adult in mice?
a. 8
b. 16
c. 23
d. 32
2. Identify the mites shown in the picture. How long is its life cycle?
ANSWERS
1. c
2. Myocoptes musculinus – 8-14 days
Anesthesia
Mert and Gunes. Antinociceptive Activities of Lidocaine and the Nav1.8 Blocker A803467 in Diabetic Rats, pp. 579-585
Domain 3: Research; T3. Design and conduct research; K3. animal models
Primary Species: Rat (Rattus norvegicus)
SUMMARY
Background: The streptozocin-induced diabetic rat is a model of chronic pain that shows signs of hyperalgesia and allodynia and may replicate signs in diabetic humans. Sodium channels blockade is one of the best-known treatments for relieving diabetes-induced pain. Recent work has suggested that A803467 (5-[4-chloro-phenyl]- furan-2-carboxylicacid [3, 5-dimethoxy phenyl]-amide) is a potent and highly selective blocker of Nav1.8 channels.
The authors investigated the antinociceptive effects of A803467 in diabetic rats with painful neuropathy.
Methods: They systemically (intraperitoneal) or locally (intraplantar) administered A803467 (or lidocaine, a nonselective sodium channel blocker, as a control) to diabetic rats (Wistar) with hyperalgesia and allodynia and then measured thermal latencies and mechanical thresholds. To assess sensory abnormalities that include hyperalgesia to noxious thermal and allodynia to innocuous mechanical stimuli, authors used thermal plantar test and a dynamic plantar aesthesiometer, respectively.
Results: With intraperitoneal administration, A803467 led to 6-fold greater reduction of hyperalgesia and 2-fold greater reduction of allodynia than did lidocaine.