Comparative Medicine - LABSG



Comparative Medicine

Volume 55, Issue 2 (April 2005)

Rodent Models of Rheumatoid Arthritis (pages 114-122)

There are many rodent models of arthritis, each with clear difference in etiology, however they all result in inflammation and destruction of one or more joints. The most widely used are the K/BxN and collagen-induced arthritis (CIA) mouse models.

Arthritis has 3 stages: inflammation, thickening of the synovium (pannus) and degradation of cartilage and bone. Rheumatoid arthritis (RA) exhibits a strong association with MHC II antigens HLA-Dr1 and HLA-DR4. There is a theory for cofactor influence, suggesting roles for cytomegalovirus, Epstein-Barr virus and enteric bacteria. Because the exact etiology of RA is not known, there are many models. This includes induced and spontaneous rodent models. Induced models induction with albumin, type II collagen, human cartilage proteoglycan, cell-wall peptidoglycans from Streptococcus and complete Freund's adjuvant(CFA). Spontaneous models may more accurately reflect the human condition. Each model is slightly different and offers unique avenues for studying this complex disease state.

The models are:

Collagen-induced arthritis (CIA): Collagen is emulsified in IFA for rats or CFA for mice and is injected intradermally in the tail. DBA/1LacJ are most commonly used mouse strain with onset of disease between days 14-21. Most often affects wrist or ankle and may take 8 weeks to run its course. Inflammation will gradually subside often accompanied by ankylosis of the affected joints.

K/BxN arthritis model: Hybrid between KRN and nonobese diabetic mice resulted in a model with developed severe destructive arthritis in all distal joints. This model is used widely today to study inflammation, immune regulation and autoimmunity.

Antigen-induced arthritis (AIA): rodents are immunized with a model antigen (i.e. BSA) followed by an intra-articular challenge with the same antigen. Arthritis it limited to the antigen-injected joint. Maximum swelling is achieve 4 days after challenge. Technique most easily performed in rats and rabbits.

Adjuvant arthritis (AA): One of the first animal models. Certain strains of rats develop arthritis after a single intracutaneous injection with CFA. It primarily affects the peripheral joints, but there is spinal involvement and other manifestations such as uveitis, gastritis and weight loss. This model is used to study efficacy of anti-inflammatory drugs.

Oil-induced arthritis (OIA): Arthritis can be induced by the intra-articular injection of IFA, mineral oil, Arlacel A (mannide monooleate) and pristane (2,6,10,14-tetramethylpentadecane). Pristane can also induce arthritis in mice following intraperitoneal injections. In the rat model, intradermal injections of pristane are required.

Proteoglycan-induced arthritis (PGIA): Link protein (90), proteoglycans and gp-39 can induce arthritis in rodents. Polyarthritis ensues in which peripheral joints and ankylosing spondylitis peak at 7-9 weeks. Spinal involvement is evident. BALB/c mice are used which allows for each acquisition of this model. SKG mice (ZAP-70 mutation): A point mutation in a BALB/c resulted in a model which develops spontaneous arthritis. Mice also develop pneumonitis and dermatitis and have high titers of rheumatoid factor. This is an excellent model for natural mechanisms leading to autoimmune injury.

TNF-alpha and IL-1ra-/- transgenic mice: Mice expressing the transgene for TNF-alpha develop a progressive, chronic polyarthritis in all joints. BALB/c mice which are deficient in the IL-1Beta antagonist receptor develop a polyarthropathy as early as 5 weeks of age. This is being used to investigate the role of IL-1Beta in rheumatic disease.

General considerations: Minimal group sizes of approximately 10 animals are necessary to detect even slight alterations in incidence or severity. Repeat studies are typically needed also. Animal welfare concerns are significant and require selection of humane endpoints. Analgesics are problematic as they can influence inflammatory pathways. The use of soft bedding and frequent assessment of clinical status is necessary.

NOTE: See chart on page 119 for comparisons of models.

Questions:

1. Which are the most frequently used mouse models?

2. What are the 3 necessary stages of arthritis?

3. What mouse model mimics autoimmune injury?

4. Pristane can be injected IP to create what arthritis model?

5. Name the first animal model of arthritis. What other clinical signs are noted?

Answers:

1. The most widely used are the K/BxN and collagen-induced arthritis (CIA) mouse models.

2. Arthritis has 3 stages: inflammation, thickening of the synovium (pannus) and degradation of cartilage and bone.

3. SKG mice (ZAP-70 mutation)

4. Oil-induced arthritis (OIA)

5. Adjuvant arthritis (AA); uveitis, gastritis and weight loss

Low-dose infectivity of Staphylococcus aureus (SMH strain) in traumatized rat tibiae provides a model for studying early events in contaminated bone injuries (pages 123-128)

This article describes an animal model of post-traumatic acute osteomyelitis (OM) by contaminating mechanically traumatized rat tibia with various doses of S. aureus (SMH strain ? known to cause human OM). Bacteria were introduced into the exposed medullary cavity of tibia. Curettage and lavage were then performed, and at different time points, rat tibia were harvested for assessment of bacterial load and determination of minimal infective doses for 50% (ID50) and 95% (ID95). The dose-response curve of inoculum showed a steep slope, indicating the model was responsive to low levels of inocula. Logistic regression analysis determined the ID50 to be 1.8x103 CFU, and ID95 to be 9.2x103 CFU. Inocula above the ID95 did not increase bacterial load in tibia at 24 hours after contamination. Intra-operative curette and lavage removed many bacteria from bone, but did not prevent subsequent infection or disease. At 15 days after contamination, most (14 of 17) tibia were infected, with macroscopic and radiological signs of established OM, despite minimal clinical signs associated with the injury. Authors conclude that this rat model mimics human long-bone infection, allowing scientists to study early pathology in contaminated bone injuries as well as evaluate clinical interventions that may reduce infection and prevent disease.

Questions:  

1. What does ?ID50? and ?ID95? stand for?

2. What cellular component does SMH strain of Staph. aureus binds to?

Answers:

1. Minimal infective doses for 50% (ID50) and 95% (ID95) of subjects.

2. Collagen.

Birth of rhesus macaque (Macaca mulatta) infants after in vitro fertilization and gestation in female rhesus or pigtailed (Macaca nemestrina) macaques (pages 129-135)

SUMMARY: In rhesus macaques, previous studies have demonstrated successful in vitro fertilization as well as the viability of early-stage embryos after cryopreservation. Heterospecific embryo transfers have been successful in multiple species (cynomolgus monkey embryo in female rhesus, Indian desert kitten to domestic cat, Przewalski horse and Grant’s zebra to domestic horses, goats to Spanish ibex kids, and ewes to mouflon lambs. This study explored the use of in vitro fertilization and gestation of rhesus macaques in female rhesus or pigtailed macaques. If successful, it would be useful to have pigtails act as a surrogate for rhesus embryos/infants since rhesus (unlike pigtails) are seasonal breeders. Therefore, it would be possible to create a more consistent supply of rhesus infants for study. Also, the technique may be useful in the conservation of endangered primate species.

Female rhesus were superovulated with a combination of recombinant follicle stimulating hormone (rFSH) and recombinant HCG. Semen was collected by penile electrostimulation. Oocytes were stripped of cumulus cells and then incubated with the semen. Selected embryos were frozen and then thawed prior to embryo transfer. Embryos were implanted in the infundibulum or oviduct 3 days after the recipient females’ estradiol level peaked. Two embryo were implanted in each female. After transfer, ultrasound examination was performed every 30 days. Infants were born by elective cesarean section. Placental tissues were collected and examined at this time.

RESULTS;

Cycle length and estradiol levels: Menstrual cycle lengths didn’t differ between rhesus and pigtails or between different seasons. Estradiol levels peaked earlier and at a higher level in pigtails.

Embryo transfers: 15 embryos were implanted in rhesus; 12 into pigtails. The efficiency of generating pregnancies from heterospecific embryo transfers was significantly lower than with rhesus recipients. 8 rhesus and 1 pigtail became pregnant. 8 rhesus infants were born (by c-section) to rhesus surrogates. 3 infants were aborted. 1 infant was born to the pigtail surrogate and subsequently grew and matured normally.

Placenta analysis: All macaques have hemochorial placentation and in all animal species placental tissues are of fetal origins. “The placenta of the rhesus-pigtailed infant was bidiscoidal with extremely rounded, thickened discs. The disks were “ball shaped” when compared with normal flattened macaque placental disks.” The umbilical cord of the rhesus-pigtailed placenta was unusually long and of small circumference. Histologically, there was hypertrophy of the chorionic layer, evidence of maternal floor infarction, and thrombosis of the placental vascular tree. Although the cause of the placental abnormalities is unknown, it was suggested that they may be the result of incompatibility between rhesus conceptus and its pigtailed surrogate manifested through partial rejection and malformation.

The conclusion of this study was that related macaques can be used for heterospecific embryo transfers. Future studies will examine ways of improving the efficacy of the process.

No questions submitted

Use of frozen-thawed oocytes for efficient production of normal offspring from cryopreserved mouse spermatozoa showing low fertility (pages 136-139)

Summary: In vitro fertilization is becoming a frequently-used tool for assisted reproduction in mice. In many cases, spermatozoa and oocytes are frozen prior to the fertilization process. This allows for transport or sharing of resources. However, spermatozoa have difficulty in penetrating oocytes because of hardening of the zona pellucida during the freezing process. The paper compared fresh and frozen gamete fertilization using intracytoplasmic sperm injection (ICSI). Unfertilized oocytes were collected following superovulation of the mice with 5 IU pregnant mare serum gonadotropin IP followed by injection of 5 IU of human chorionic gonadotropin 48 hours later. Sperm were collected from the cauda epididymides of male mice. Gametes were frozen and thawed according to standard protocols. ICSI was accomplished using piezo pulses with a piezo-micromanipulator.

Compared with fresh unfertilized oocytes, frozen-thawed unfertilized oocytes were highly tolerant to damage by injection. Frozen-thawed oocytes that survived after sperm injection developed normally and gave rise to offspring. These offspring also had reproductive ability; female mice became pregnant and gave birth to normal pups. This technique was performed in C57Bl as well as transgenic mice with the same success rate. These results indicate that ICSI is an efficient technique for offspring production with frozen gametes.

Questions:

1. What is the technique for superovulation in mice?

2. What structure is collected for sperm harvesting in mice?

3. What is ICSI?

Answers:

1. 5 IU of pregnant mare serum gonadotropin IP followed by 5 IU of human chorionic gonadotropin 48 hours later.

2. cauda epididymides

3. intracytoplasmic sperm injection

Relationship Between Storage Temperature and Fertilizing Ability of Freeze-Dried Mouse Spermatozoa (pages 140-144)

Summary: The authors describe the fertilizing ability of freeze-dried mouse spermatozoa that has been stored at 4 different temperatures for 1 week, 1, 3, and 5 months. They compared the temperature and times with fertility and normalcy of offspring produced. Sperm stored at -70, -20, and +4 degrees centigrade for 5 months produced normal offspring. Sperm stored at +24 degrees centigrade were maintain well for 1 month but degraded thereafter. The conclusion was that spermatozoa can be stored at +4 degrees for at least 5 months without harming the genetic material. They authors also suggest that sperm can be shipped at +24 degrees without harming the sperm.

Questions:

1.What are the advantages of freeze drying sperm rather than cryopreservation?

2.What are the disadvantages of freeze drying sperm rather than cryopreservation?

Answers:

1 Spermatozoa can be preserved without cyroprotectants and do not require a supply of liquid nitrogen. They do not required dry ice to ship.

2. Spermatozoa lose their motility after rehydration and intracytoplasmic sperm injection is required for fertilization of oocytes.

Survey of Captive Cynomologus Macaque Colonies for SRV/D Infection Using Polymerase Chain Reaction Assays (pages 145-149)

The eradication of exogenous of SRV/D from breeding colonies of Asian Macaques is an essential goal. Not all animals carrying the virus present with detectable antibodies for serological testing and virus isolation can be cost prohibited and labor intensive. PCR is a rapid effective testing method for a multitude of SRV/D serotypes. The authors designed an SRV/D-T specific PCR primer set based on sequences of the aligned gag regions of SRV/D-1,-2, and -3 and SRV/D-T. A SRV/D-T specific nested primer set was designed to increase the sensitivity of the PCR. Cynomologus monkeys in a conventional and SPF colonies were tested using a direct PCR method with EDTA (ethlylenediamine tetraacetic acid) treated whole blood comparing SRV/D-T specific primer set with established primer sets that detect SRV/D. Utilization of established primers for SRV/D-1,-2 and-3 yielded no signals in either colony. Use of primer sets for SRV/D that simultaneously detect multiple SRV/D subtypes failed to identify SRV/D. SRV/D-T specific primers failed to amplify any products in the SPF animals tested. Testing of the conventional colony using SRV/D-T specific primers amplified products from blood DNA from 11 of 49 monkeys. The 381-bp products were sequenced to confirm that SRV/D-T was most likely the predominant subtype present.

Questions

1). What does EDTA stand for?

2). SRV/D-T specific primers were designed based on the nucleic acid sequences in the pol region of SRV/D-1,-2,-3 and SRV/D-T true or false

3) By treating whole blood with EDTA yields genomic DNA to be used as a template for nested PCR allowing the detection of SRV/D-T from whole blood eliminating the need to purify PBMCs? True or False

4) For the colony surveyed the established SRV/D primers failed to detect SRV/D-T from positive animals? True or False

Answers

1). Ethlylenediamine tetraacetic acid.

2). False gag region

3). True

4). True

Title:  Ovine Model to evaluate Ovarian Vascularization by Using Contrast-Enhanced Sonography (pages 150-155)

Summary: This study evaluated a sheep model for use of a transvaginal ultrasound contrast agent to visualize the microcirculation of normal ovaries.  Purpose for this study is, in humans, detection of ovarian tumors is hampered by their small size.  Current techniques to detect ovarian tumors use ultrasound with contrast agents.  The earlier (smaller) that tumors can be detected, the better chance of successfully treating.  Sheep were chosen for their size similarity to humans and also their ovaries behave similarly to humans histochemically and hormonally.  Sheep do not normally get ovarian tumors, but the authors currently are trying to develop a sheep ovarian tumor model.  Ultrasound contrast agents consist of microbubbles that are around 3 microns in size.  These bubbles stay in the vasculature for a short period of time, then are expired in the exhaled air within 15 minutes after injection.

This study used a bolus injection of Sonovue, which is a second-generation agent in a suspension of stabilized sulphur hexafloride.  The first phase of the study compared enhancement in the ovary at three different doses (2.5, 5.0, and 7.5 ml) of agent.  It was determined that once a plateau of enhancement is seen, higher doses make little difference.  The dose of 5 ml per bolus was optimal.  The second phase of the study compared enhancement of signal, time to peak enhancement, and enhancement ratio.  The study compared ovaries at different stages of development, from inactive to estrus to luteal.  Overall, they found an enhancement of 248% with use of a contrast agent.  Time to enhancement was 10.8 sec and the peak enhancement was seen at 24.7 sec.  The ovary on the side of ovulation and subsequent corpus luteum had a stronger enhancement than the non-cycling ovary (358% vs 175%).

The authors summarized by stating the sheep is an excellent model for transvaginal ultrasound examination of ovaries and with use of contrast agents, the microvasculature density can be assessed.  An increase in microvasculature density may be caused by an ovarian tumor, but the authors warn that stage of the ovarian cycle can influence this.

 Questions: 

    1.  Sheep were chosen because of their similar size to humans,  their ovaries behave similarly to humans histochemically and hormonally, and they get spontaneous ovarian tumors,  T or F

    2.  Ultrasound contrast agents work by _____________ the ultrasound signal.

a.  Enhancing

b.  Blocking

c.  Obliterating

3.  Ultrasound contrast agents generally leave the body within _______ minutes via the __________.

Answers:

1:  False

2:  A

3:  15 minutes,  lungs

Reference Cardiopulmonary Values in Normal Dogs (pages 156-161)

Cardiopulmonary values on 97 instrumented, unsedated, normovolemic dogs. Body weight; arterial and mixed-venous pH and blood gases; mean arterial, pulmonary arterial, pulmonary artery occlusion, and central venous blood pressures; cardiac output; heart rate; hemoglobin; and core temperature were measured. Body surface area; bicarbonate concentration; base deficit; cardiac index; stroke volume index, systemic and pulmonary vascular resistance indices; left and right cardiac work indices; alveolar partial pressure of oxygen (pO2) ; alveolar-arterial pO2 gradient (A-apO2); arterial, mixed-venous, and pulmonary capillary oxygen content; oxygen delivery; oxygen consumption; oxygen extraction; venous admixture; arterial and mixed-venous blood CO2 contents; and CO2 production were calculated. In the 97 normal, resting dogs, mean arterial and mixed-venous pH were 7.38 and 7.36, respectively; partial pressure of carbon dioxide (pCO2), 40.2 and 44.1 mm Hg, respectively; base-deficit, -2.1 and -1.9 mEq/liter, respectively; pO2, 99.5 and 49.3 mm Hg, respectively; oxygen content, 17.8 and 14.2 ml/dl, respectively; A-a pO2 was 6.3 mm Hg; and venous admixture was 3.6%. The mean arterial blood pressure (ABPm), mean pulmonary arterial blood pressure (PAPm), pulmonary artery occlusion pressure (PAOP) were 103, 14, and 5.5 mm Hg, respectively; heart rate was 87 beats/min; cardiac index (CI) was 4.42 liters/min/m2; systemic and pulmonary vascular resistances were 1931 and 194 dynes.sec.cm-5, respectively; oxygen delivery, consumption and extraction were 790 and 164 ml/min/m2 and 20.5%, respectively. This study represents a collation of cardiopulmonary values obtained from a large number of dogs (97) from a single laboratory using the same measurement techniques.

Questions:

1. What is the significance of the venous admixture measurement?  Is it usually increased or decreased with pulmonary parenchymal disease?

2. True or false:  Except for heart rate and mean blood pressure, most of the cardiopulmonary values in this paper fall within the range of normal human values.

3.  What is the significance of D02 (oxygen delivery, a calculated value)?

Answers:

1.  It is a calculated value used to assess lung oxygenated efficiency.   The value is usually increased with pulmonary parenchymal disease.

2.  True

3.  Oxygen delivery, as the name implies, represents an overview of cardiopulmonary performance.  Any disease process that decreases blood oxygenation, hemoglobin concentration or cardiac output tends to diminish D02.

 

Cardiomyopathy in Captive Owl Monkeys (Aotus nancymae) (pages 162-168)

   Authors characterized incidence of cardiac disease in owl monkeys via use of echocardiography.  A survey of a colony of owl monkeys over the past 15 years revealed a significant amount of cardiac disease.  Although no animals showed clinical signs of cardiac disease at the time of these exams, some monkeys died prior to completion of this study (e.g. 2nd exam, 14 months following initial exam).  A pathology exam (gross and histopath.) were conducted of the deceased animals, and the data obtained from the echocardiography measurements supported the pathological evidence of dilated cardiomyopathy in this colony.

  Authors noted that animals found with a questionable diagnosis of cardiomyopathy during the first exam ultimately showed progression of the disease over time.  M-mode and 2D echocardiograms were taken, using right parasternal short-axis views.  Since the colony had a high prevelance of disease, authors were reluctant to establish reference intervals for echocardiography for this species.  Hopefully, preliminary information can be utilized from this study to pursue further echocardiographic guidelines in this species.

 Questions:

1.  Which other primate species has cardiomyopathy been identified?

    

    a.  vervet                                               d.  baboons

    b. squirrel monkeys                                  e.  owl monkeys

    c. all of the above                                    f.  b, d, and e

2.  Which view for conducting the echocardiogram exams provided the most repeatable,

     consistent view?

     a.  dorsal view                                         c.  parasternal short-axis view

    b.  parasternal long-axis view                     d.  ventral recumbency view

3.  List some other Differentials for cardiac hypertrophy.

Answers:

1.  f         2.  c        3.  chronic systemic hypertension; trypanosomiasis; taurine deficiency

Age-Related Diffuse Chronic Telogen Effluvium-Type Alopecia in female Squirrel Monkeys (Saimiri boliviensis boliviensis) (pages 169-174)

Summary: The purpose of this study was to examine the pathology associated with chronic alopecia observed in females from a colony of squirrel monkeys.  Materials and Methods:  All monkeys were fed a high protein monkey chow supplemented with fresh fruit and vegetables.  They were housed in indoor-outdoor pens.  One hundred (100) adult females and ten (10) adult males  were randomly selected for inclusion in this study.  Evaluation included physical examination, evaluation of haircoat, and serum biochemistry profile.  To evaluate condition of hair, trichograms and skin biopsies were performed and hair density was calculated.  Finally, behavior was evaluated in 2 groups consisting of 50 monkeys each.  Results:  No hair abnormalities were observed in the 10 male monkeys.  Of the 100 females,  65 had alopecia and 35 had no evidence of alopecia.  Statistically significant differences were observed for age and parity, but no differences were observed for body weight and serum chemistry results.  Hair densities were greater in the control group.  The trichogram demonstrated twice as many club hairs (telogen hairs) in the alopecia group versus the control group.  Analysis of behavior did not find enough activity to account for the hairloss observed in the alopecia.  Dominant males were responsible for most of the aggressive behavior directed against females in the colony.  Conclusion:  After discussion of pathophysiology of several conditions in which alopecia is a symptom, the authors stated that the hairloss pattern observed was consistent with chronic telogen effluvium.        

Questions: 

    1.  Give the genus species of the squirrel monkeys in this study.

    2.  In a trichogram, how are telogen hairs identified?

    3.  What are the 3 differential diagnoses for diffuse scalp hair loss in human females?

    4.  Define telogen effluvium.

    5.  The lifespan of a hair is determined by the duration of anagen phase.  T or F

    6.  The alopecia observed in the squirrel monkeys in this study was statistically associated with:

                                    a) hormone levels

                                    b)  age 

                                    c)  parity

                                    d)  position of dominance within group

                                    e)  age and parity

Answers:

1. Saimiri boliviensis boliviensis 

2. Telogen hairs have a thinner shaft and bulbous ends ("club" hairs). 

3. a) androgenetic alopecia, b)  chronic telogen effluvium, and c)  alopecia arreta.

    4.  Telogen effluvium is the disruption in the hair cycle resulting in increased shedding of telogen hairs.  Can be acute or chronic disease.

    5.  True.

    6.  The correct response is : e) age and parity

Susceptibility of rats to corneal lesions after injectable anesthesia (pages 175-182)

Corneal injury is a common side effect after general anesthesia in rats.  This study examined several different anesthesia methods to determine if the incidence of corneal opacities or ulcers was different among the various methods.  This study also examined strain variation in the development of corneal ulcers.   It was determined that animals anesthetized with ketamine-xylazine were at greater risk of developing corneal ulcers compared to animals anesthetized with inhalational agents (isoflurane or enflurane).  It was also noted that Wistar, Long-Evans (LE), and Fischer 344 (F344) rats were more likely to develop lesions than Sprague-Dawley (SD) and Lewis rats.

Materials and Methods: Results for this article were taken from three separate groups: a retrospective study of animal records and tissues used in other studies, female Wistar rats assigned to 5 experimental anesthetic groups, and male rats of 5 different strains anesthetized with ketamine-xylazine.  Retrospective study- Histopathology was performed on eyes from 402 male and female Wistar rats used in other studies.  Several anesthetic methods were used in this portion of the study: enflurane, isoflurane, ketamine-xylazine, Hypnorm-midazolam.   Anesthetic influence- The five experimental groups were O2 control without jackets, O2 control with jackets, ketamine-xylazine, pentobarbital, Hypnorm-midazolam, and isoflurane.  Strain influence- The five strains compared were Wistar, F344, SD, LE, and Lewis.

Results: Retrospective study- Animals anesthetized with ketamine-xylazine demonstrated the greatest incidence of corneal lesions and ulcers- 71% of animals had lesions of a score of 2 or greater.  Animals anesthetized with inhalational methods had only a 2% rate of corneal changes (one animal).  There were no sex-associated differences. Anesthetic influence- Ketamine-xylazine anesthesia was associated with the greatest incidence of corneal changes- 66%.  In comparison, only 11% of animals anesthetized with isoflurane developed corneal changes.  Strain influence- F344 rats were most sensitive, developing the greatest number and most severe lesions. Wistar and LE rats also developed corneal lesions after anesthesia.  SD and Lewis rats were more resistant to changes.

Discussion: Results of this study indicate that despite precautions taken to prevent corneal damage (ophthalmic ointment applied at anesthetic induction), corneal lesions are common in rats.  Severe lesions are associated with ketamine-xylazine anesthesia and with certain strains of rats.  Lesion development is thought to be associated with the vasoconstrictive effects of xylazine, and suppress the parasympathetic tone to the iris.  This may lead to local and systemic hypoxia resulting in corneal injury.  Repeated administration of eye lubricant may not have a beneficial effect, as studies in both humans and rats show that repeated application of eye lubricant after traumatic injury may exacerbate corneal damage.

Questions:

Which anesthetic method is associated with the greatest risk of corneal damage?

T or F- Male rats develop corneal lesions at a greater rate than do female rats.

T or F- Use of ophthalmic ointment can eliminate the risk of developing corneal lesions in anesthetized animals.

Answers:

ketamine-xylazine

False- there is no sex-associated difference

False- All animals in this study received ophthalmic ointment at anesthetic induction, yet many developed corneal lesions.

A National Survey of Laboratory Animal Workers Concerning Occupational Risks for Zoonotic Diseases (pages 183-191)

The investigators conducted a cross sectional epidemiological study to estimate the frequency of all episodes associated with laboratory animals regardless of their medical significance, severity, consequences, or other aspects that will affect OSHA standards. A self administered survey questionnaire, including return-reply postage, was mailed to all persons in the survey. Of 4802 survey questionnaire supplied, 30% responded back, out of which 94% had worked with lab animal for past five years and 84.5% worked with fresh tissues, blood or body fluids. Of these respondents there was an estimate of 6202 person-years of zoonotic disease exposure. 70.1% of the respondents had bachelor's degree and 26.6% had doctoral degree.

The overall estimated annualized incidence rate of occupationally acquired infection with zoonotic agents from laboratory animals from this study was 45 cases per 10,000 worker-years. Statistical analysis showed that persons working at AAALAC accredited institutions that had received educational information about zoonotic diseases and had more years of experience were less likely to have been medically evaluated for exposure to a laboratory animal zoonotic agent at work. Although the data from this study confirmed that the zoonotic diseases of laboratory animals continue to be important, although rare in the present environment. The data presented in the study may be biased, especially by recall bias.

Questions.

True or False

1. The incidence of occupational acquired infection from lab animal are high for the lab workers.

2. The incidence of illness acquired from lab animal increases with education.

3. Most of the institutions do not have a safety office/officer to evaluate zoonotic diseases from lab animals.

Answers.

1. False

2. False

3. False

Successful Cyclosporine Treatment for Atopic Dermatitis (AD) in a Rhesus Macaque (Macaca mulatta) (pages 192-196)

A juvenile (1 year old ) female rhesus macaque (Macaca mulatta) developed a chronic active skin condition characterized by pruritus, erythema, alopecia, scaling, exfoliation, and lichenification. Lesions were limited to the ventrum, specifically rostral mandible and neck, axilla and inguinal regions, distal extremities, and interdigital regions. Differential diagnoses included infection, dietary deficiency, metabolic abnormality, endocrinopathy, and immunological injury. Diagnostic tests included complete hemogram, serum chemistry, skin scrapes for ectoparasite detection, hair plucks for dermatophyte culture, and a serum-based hypersensitivity panel. All results were within normal limits. Dermal biopsies revealed lesions consistent with active allergic dermatitis, and a diagnosis of atopic dermatitis was made. Oral cyclosporine (5 mg/kg daily) rapidly eliminated clinical evidence of dermatitis. Histologically, lesions resolved after 12 months of treatment. Atopic dermatitis is an inflammatory skin condition for which there are neither pathognomonic clinical or diagnostic features nor a single successful therapy. Basic criteria such as pruritus, lichenification, a chronic course, and history of allergies strongly support the diagnosis. One successful therapeutic agent is a macrolide calcineurin inhibitor, cyclosporine. It represents a safer class of immunomodulatory drugs than corticosteroids and provides targeted alteration of lymphocyte function.

Questions:

1)      Diagnostic tests to confirm AD are unreliable, suffering from inadequate specificity and sensitivity. (T/F)

2)      Oral cyclosporine (5 mg/kg daily) rapidly eliminated clinical evidence of Atopic dermatitis.(T/F)

3)       Mode of action of cyclosporine might be due to preferential inhibition of  T lymphocytes (T/F)

Answers:

1)      T

2)      T

3)      T

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