Laboratory Animal Sciences 48 (1)

Laboratory Animal Science 48 (1)
1998

Animal Models of Muscular Dystrophies. Laboratory Animal Science 48 (1): 008.
This article is an overview of animal models of muscular dystrophy (MD). MD is a group of hereditary disorders resulting in muscle weakness due to muscle fiber degeneration and necrosis. Muscle fibers regenerate, with increased interstitial connective tissue. Eventually muscle fibers are replaced with fatty/fibrous tissues. This leads to respiratory and cardiovascular failure.
    Duschenne MD (DMD) is the most common human form of MD. It is xlinked recessive. Muscle lacks dystrophin. Dystrophin is normally located just beneath the sarcolemma (surface membrane of muscle fiber).   Predominantly proximal muscle weakness and hypertrophy of calf muscles.
Animal models:
1. Xchoromosomelinked MD mouse (mdx):
skeletal muscle has dystrophic changes ie. muscle fiber necrosis and regeneration
active regeneration compensates for the necrosis so that muscle fiber is NOT replace with fibrous tissue
necrosis subsides at 34 months of age, necrosed fibers regenerated
Difference from human disease:
    no clinical muscle weakness
   regenerative vs. progressive
2. Canine MD (xmd dog)
   colony of golden retrievers (University of MissouriColumbia)
   xlinked recessive
   progressive muscle weakness
3. Feline MD
   colony of cats (University of MissouriColumbia)
Difference from human disease:
hypertrophy of the sekeltal muscle, tongue and diaphragm "hypertrophic feline MD"
4. Dystrophin gene knockout mouse
   skeletal muscles hypertrophic, as in human DMD patient's calves
Difference from human disease:
   only mild muscle weakness
   muscle fibers regenerate, no intersitial fibrosis
Congenital MD
Autosomal recessive. Muscle weakness and hypotonia from early infancy.
Two types
(i) Classical type
(a) merosinpositive form
(b) merosindeficient form
   chromosome 6 affected, codes for merosin
   merosin absent from basement membrane of muscle fiers and Schwann cells
   respiratory and feeding difficulties
   can sit up but do not become ambulatory
   dystrophic muscle changes, with marked interstitial fibrosis
white matter abnormality, but signs of CNS dysfunction NOT prominent
(ii) Fukuyama type
striking CNS abnormalities
Animal Model for merosindeficent form:
Dystrophic mouse (dy)
heterozygote is normal
homozygote develps hinglimb paralysis and twitching at 35 weeks of age, dies from emaciation around 810 weeks
muscle fiber necrosis, regeneration, interstitial fibrosis
Difference from human disease:
ventral spinal roots marked reduction in myelinated fibres, agrregates of naked axons (lack Schwann cells), therefore not regarded as a useful model of MD
   chromosome 10
Severe Childhood Autosomal Recessive MD (SCARMD)
rare, symptoms mimic DMD, including proximal muscle weakness and calf hypertrophy
sarcogylcanopathy
Animal Model: Dystrophic hamster (Syrian background)
mild skeletal muscle signs; lesions resemble mdx mouse (regenerative process compensates for necrotic process)
cardiac muscle preferentially involved, leading to fatal cardiac insufficiency by one year of age
calcificaition in muscle fasicles increases with age
Facioscapulohumeral muscular dystrophy (FSHD)
affects facial and shoulder muscles
autosomal dominant
chromosome 4
Animal Model: Myodystrophy (myd) mouse
clinical signs differ from human at 3 weeks of age some small with abnormal gait, others normal
lesions resemble mdx mouse
chromosome 8
autosomal dominant
Other possible models of MD:
Dystrophic Chicken
autosomal dominant
responsible gene or proten defect unknown; unknown if this will be a good model for human disease
white muscle affected, red muscle spared
leg muscles are red/white, therefore muscle weakness is not evident
pectoral (breast) muscle is white do 'flip test' lay chicken on its back, affected chickens cannot get up
progressive disease, i.e. muscle necrosis, regeneration, interstitial fibrosis
intracytoplamic vacuoles
QUESTIONS
1. How is Duchenne muscular dystrophy inherited?
a) autosomal recessive
b) autosomal dominant
c) xlinked recessive
d) a or c
2. Which mouse strain is a model of Duchenne MD?
a) dy /dy
b) mdx
c) myd
d) dystrophin gene knock out
e) a and c
f) b and d
ANSWERS
1. c (xlinked recessive)
2. f

Clinical Disease Associated with Simian Agent 8 Infection in Baboons. Laboratory Animal Science 48 (1): 018.
   SA8 is a neurotropic alphaherpesvirus. It has been isolated in African greens and baboons. Although very similar, they are distinct viruses and it has been proposed to rename SA8 in the baboon Herpesvirus papio 2. SA8 has been isolated in the trigeminal ganglia of baboons, suggesting recurrent or latent infections.
    Lesions are primarily genital, suggesting venereal transmission. Oral lesions are seen only in juvenile baboons (<3 years old). Lesions are more severe, of longer duration and recur more often in females. Complications include vaginal stenosis and subsequent breeding problems, possible urethral blockage with subsequent pyelonephritis. The virus is also associated with neoplasia.
    The disease process of SA8 is associated with secondary bacterial infection. Neoplasia is probably related to longterm inflammation and the virus itself.
Questions:
1. SA8 virus is identical in African greens and baboons. T or F.
2. SA8 in baboons is a good model for what human herpesvirus? Why?
Answers
1. False they are similar, but distinct. It is proposed that SA8 in baboons be renamed Herpesvirus papio 2.
2.   Herpes simplex virus type II (HSV2). More severe in females, associated with neoplasia, similar clinical signs (genital lesions), and the viruses are very similar.

Shedding and transmission of baboon Herpes Virus Papio 2 (HPV2) in a breeding colony. Laboratory Animal Science 48 (1): 023.
Baboons were screened twice yearly (during routine TB testing for current Okla. State colony members or immediately or within 5 days of arrival (for animal purchased from Yerkes or acquired as imports from Africa , respectively). Blood samples and swab specimens from the oropharynx and vagina or penis were obtained from adult baboons and only swabs from oropharynx were collected from juveniles and infants. Sera were tested using ELISA; Swabs specimens were processed for virus isolation. Isolates were confirmed using PCR/restriction length fragment polymorphism analysis. 2 reference HPV2 strains were used as well as 1 strain each of SA8, Bvirus strain , HSV1, and HSV2.
Results: 128 baboons were tested over 1.5 years; shedding of infective virus was detected in 13 of 342 swabs specimens, each representing shedding by a different animal. Among longterm colony members, infective virus was recovered only twice (5 of 236 swabs specimens from 5 individuals) All but one of these were infants rather than adults, and all animals were shedding virus from the oral cavity. Four of these 5 were within a single breeding group. None of the 31 wild caught baboons added to the colony were shedding infective virus although 93.5% were seropositive for HPV2. 6 of 8 baboons transferred from Yerkes to Oklahoma (all were seropositive) were shedding HPV2 either orally (n=3) or genitally (n=3). 2 of 6 juveniles in this shipment were also found shedding virus in the oropharynx. Conclusion: Although venereal transmission of HPV2 occurs among adult animals, oral infection of young, sexually immature baboons is not uncommon. HPV2 may be acquired at an early age as oral infections; shedding of virus under normal husbandry conditions is uncommon; and overall, HPV2 infections in baboons appear to be similar to B virus in macaques.
Questions:
1. Herpesvirus papio 2 (HPV2) is antigenically and genetically closely related to what 2 other notable monkey viruses? What human virus?
2. HPV2 is a/an (choose one : alpha, beta, gamma) herpes virus?
3. What is the prevalence of HPV2 seropositivity in captive breeding colonies and newly imported wild baboons?
Answers:
1. African green monkey virus SA8 and monkey B virus of macaques(Herpes simiae); human herpes simplex 1 and 2 (HSV1 and HSV2)
2. alpha
3. approx. 85%

Epizootic of Group B Streptococcus agalactiae Serotype V in DBA/2 Mice. Laboratory Animal Science 48 (1): 029.
Authors describe an epizootic of Streptococcus agalactiae (group B) serotype V in a maximum barrier production colony (Taconic labs) of immunocompetant mice (DBA/2). (A description of the colony management and equipment was provided).
   Initial signs were an increase in weekly morbidity and mortality (from 0.1% to 0.6%) in 6 weeks. .. primarily (40%) attributable to an increase in morbidity (as evidence by rough haircoat and signs of depression. As per routine husbandry practices for that facility, moribund mice were euthanatized and necropsied. Initial necropsy results from 3 such female DBA/2 mice noted pale foci within and on the kidney and/or heart, from which Streptococcus sp was isolated in pure culture. 91% of 99 subsequent animals sent to necropsy had similar lesions in multiple organs (most commonly in/on the heart (75%), kidneys (60%), spleen (47%) and liver (30%). Other lesions were thoracic adhesions, splenomegaly, metritis, focal pale nodules on and in lung and lymph nodes, enlarged kidneys, renal pelvic exudates, hepatomegaly,and cervical lymphadenitis. Microscopically, bacterial colonies were noticed associated with lesions, and histologic diagnoses included severe chronic nephritis and pyelonephritis (87%), necrotizing suppurative myocarditis (40%), chronic suppurative metritis (27%), acute multifocal to coalescing hemorrhagic pneumonia (27%), mild acute hepatitis (13%), and acute meningitis (7%). Strep isolate was speciated as agalactiae. The syndrome appears to have originated as an ascending pyelonephritis that progressed to septicemia.
    Epizootiologic studies were conducted.. Initially fecal samples were collected, but later oropharyngeal swabs (shown to provide a more effective method for clinical isolation) were taken from breeders in production cages or from 2 randomly selected animals from nonproduction cages. Affected colonies were tested at least 2 times.. 1 or more months apart. Positives were culled. Organism was isolated primarily from DBA/2, CD2F1, ad B6D2F1 breeding colonies. Because most animals with gross lesions were older breeding animals, authors looked at effect of age and sex on organism isolation in these 3 colonies. Mean age was 30 (range, 6.559), 19.5 (range, 7 29), and 21 (range, 832) weeks.   A modified lethal dose and strain susceptibility study was performed in which female Swiss Webster and DBA mice were infected with this S. agalactiae strain at various serial dilutions. DBA/2 mice were 1000 times more susceptible than SW mice.
   The epizootic was controlled by eradication of the breeding colony, disinfection of the barrier, and autoclaving of all equipment.
Questions:
1. T/F Beta hemolytic streptococcal infections are the most common cause of morbidity and mortality in mice.
2. T/F The most common Lancefield group associated with streptococcal infections in mice is Group B.
3. Epizootiologically, this organism causes a/an acute/chronic infection with high/low morbidity and high/low mortality.
4. T/F A possible source of infection was the caretakers.
Answers:
1. False.
2. False. Most commonly it is Group C, although infections with Groups A, B, D, and G have been reported.
3. chronic; high; low;
4. True. The only thing not sterilized in this production facility was the caretakers. The facilities regional health care facility provided info on the prevalence of S. agalactiae in the human population.. it was the 7th most common isolate (3.62%of all isolates) in that geographic area (Germantown, NY), and found most commonly in urine (49.2%), wounds (28%), female repro tract (11%), and sputum/ throat (7.6%).

Neuropathologic findings associated with seizures in FVB mice. Laboratory Animal Science 48 (1): 034.
In a number of mouse strain spontaneous audigenic seizures have been described: DBA/2J, SJL/J, LP and now FVB. In the FVB mouse the histological findings include necrosis of the pyramidal cell layer and hypertrophy of asterocytes with increased GFAP staining in the brain. These findings are consistent with ischemic cell change associated with status epilepticus in humans. In some animals focal hepatic necrosis was observed.
QUESTIONS:
1. What may induce seizures in FVB mice?
2. Which mouse inbred strains are prone to audiogenic seizures?
3. What are the main neuropathologic findings associated with seizures in mice?
ANSWERS:
1. tail tattooing, fur clipping, fire alarms
2. DBA/2J, SJL/J, LP, FVB
3. ischemic cell change: necrosis of pyramidal cell layer, hypertrophy of asterocytes

Pathogenicity of Mycoplasma volis in mice and rats. Laboratory Animal Science 48 (1): 038.
Mycoplasma volis is a newly described organism found in the prairie vole (Microtus ochrogaster). After experimental intranasal inoculation in mica and rats it causes a subclinical infection with seroconversion. The organism may cause mild pneumonia in mice and hyperplasia of bronchial associated lymphoid tissue in rats. Mycoplasma volis is infectious for mice and rats and has thus to potential to interfere with biomedical research. Wild caught voles should not be housed with mice and rats.
QUESTIONS:
1. Name a newly isolated Mycoplasma strain that is infectious for mice and rats.
2. Which clinical signs are caused by M. volis infection in mice and rats?
ANSWERS:
1. Mycoplasma volis
2. none

Rapid Diagnosis of Simian Varicella Using the Polymerase Chain Reaction. Laboratory Animal Science 48 (1): 045.
Simian varicella virus (SVV) causes a highly contagious disease with clinical signs of fever, lethargy and vesicular skin rashes on the face, abdomen and extremities. SVV is a herpesvirus that is antigenically and genetically related to varicellazoster virus (VZV), which causes chickenpox (varicella) and shingles (herpes zoster) in humans. A polymerase chain reaction (PCR) assay using oligonucleotide sequences of highly conserved regions of SVV was developed. The PCR assay was able to detect SVV DNA in cell cultures and clinical samples (i.e., skin rash swabs and peripheral blood lymphocytes) from infected monkeys. The specificity of the assay was substantiated by the lack of amplification products from 2 other Old World monkey herpesviruses (i.e., herpes B virus, simian 8 agent), 2 New World monkey herpesviruses (i.e., Herpesvirus ateles, Herpesvirus saimiri), and 2 human alphaherpesviruses (i.e., HSV1, VZV).
Questions:
1. Name 3 Old World monkeys in which simian varicella has caused epizootics?
Answers:
1. African green and vervet monkeys (Cercopithecus aethiops); patas monkeys (Erythrocebus patas); cynomologus (Macaca fascicularis); pigtail (macaca nemestrina)

Prevalence of Enterotropic and Polytropic Mouse Hepatitis Virus in Enzootically Infected Mouse Colonies. Laboratory Animal Science 48 (1): 050.
Fifteen (15) different isolates of Mouse Hepatitis Virus (MHV) with 92.799.7% homology were identified from 19 independent enzootically infected mouse colonies in Switzerland. The tissue tropism of each isolate was determined by histopathological lesions in the brain, liver, spleen and intestine of nude sentinels and/or experimentally infected immunocompetent infant mice. Fourteen of the isolates elicited either intestinal lesions alone or intestinal in combination with hepatic lesions. The authors conclude that based upon the results that enterotropic MHV is more common than polytropic (respiratory) MHV in mouse colonies.
Questions:
1. MHV is a RNA virus of the family ______________.
2. True or False: Most epizootic infections with MHV in adult mice are subclinical.
Answers:
1. Coronaviridae
2. True

Improved Guinea Pig Model of Cardiac Tachyarrhythmias. Laboratory Animal Science 48 (1): 055.
In the past large animals such as dogs, pigs, rabbits, and calves have been used as models for studying short-term therapeutics in ventricular tachycardia because rodent models did not maintain the tachycardia long enough to evaluate response vs. spontaneous recovery. This paper discusses a method to achieve tachycardia of a duration >30 sec. which is sufficient for evaluating short-term therapeutic effects, thus providing a rodent model for such studies.
The model utilizes an esophageal and a periapical wire introduced via a needle passing through the diaphragm to pace the heart, a carotid catheter to measure blood pressure, and stimulation on one or both sides of the chest to induce the ventricular tachycardia (VT). The best result for prolonged VT was a rapid pacing of the heart followed by T-wave stimulation. Hearts >2.5 gm (guinea pigs > 800 gm) gave the best results.
No questions

Pulmonary Eosinophilia and Inflammation in Allergic Mice. Laboratory Animal Science 48 (1): 061.
Human Disease- Pulmonary Eosinophilia and inflammation in allergic asthma.
Model- Pulmonary Eosinophilia and inflammation in allergic mice
      Disadvantages of other models-allergic response in some animals is mediated by IgG. Monkeys and sheep- less available and poor genetic homogeneity.
     Advantages of this model- allergen challenge is mediated by IgE as in humans. Many immunological reagents and cell markers available for murine models.
     Model- B6D2F1- sensitized w/ IP injection of 15 ug. ovalbumin (OVA) adsorbed to 2 mg of alum(AIOH3) gel in saline on day 0 and 5.
     Day 12 serum level of IgE is elevated, animals are challenged w/aerosolized OVA (0.5%) for 1h in morning and afternoon.
     Animals are then sacrificed at different times.
     4-8 hours post challenge-few eosinophils, mRNA for cytokines IL-5 and IL-4 (regulate Eos influx) are increased in lung tissue.
     24h post challenge- large numbers of Eos surrounding blood vessels and the submucosal area of the bronchi and bronchioles.
     2-3 d post challenge- peak increase in Eos
     Histo- 24-48h post challenge epithelial damage, submucosal edema, increase in goblet cells, increase in mucus secretion
     Similarities w/ human disease- Eosinophil infiltration in the BAL fluid and lung tissue, histo changes damage and sloughing of airway epithelium, thickening of basement membrane, submucosal edema, and hyperplasia/hypertrophy of mucous cells.
     Increase in IL-4,-5, decrease in inflammation w/ corticosteroids
     Tx w/ antibodies to IL-4, -5 reduce severity of pulmonary eosinophilia, T cells and Mast cells may be source of cytokines.
No questions

Animal Model of Uterine Adenomyosis: Induction of the Lesion in Rats by Ectopic Pituitary Isografting. Laboratory Animal Science 48 (1): 064.
Uterine adenomyosis (or "internal endometriosis") is a benign pathologic disorder whereby endometrial components (glands and stroma) invade the myometrium. It occurs spontaneously in humans and experimental animals. Symptoms in humans include pain, profuse bleeding, and sterility. Adenomyosis can be induced by repeated treatments with estrogen and/or progesterone over a long period in mice, rabbits, guinea pigs, and monkeys.
    In mice, an anterior pituitary gland graft induces adenomyosis associated with hyperprolactinemia, suggesting an important role for prolactin in the genesis of adenomyosis. The authors report a Wistar/Tw rat model in which the lumen of each right uterine horn of 40dayold female rats was grafted with a single anterior pituitary gland from agematched male rats. Adenomyotic changes were not found in the uterus from six shamoperated control rats, whereas 6 of 8 pituitary grafted rats developed adenomyosis 12 months after surgery. There was growth of aberrant endometrial tissues, glandular and stromal components, within the inner layer of the myometrium (grade 2 according to the classification of Mori and Nagasawaoutlined below).
    The most striking ultrastructural change of the myometrium in rats with adenomyosis was the involution of the muscle cells of the inner layer bundle (see photomicrographs and electron micrographs pp.6567). The disintegration of inner smooth muscle cells is the most crucial event in the development of adenomyosis. In general, ectopic pituitary gland isografting produces a severe condition in mice characterized by subserosal nodule formation. In Wistar rats, the condition is mild. The incidence, degree, and duration of adenomyosis is influenced by the strain of mouse used; this may also be true for rats.
    Prolactin and progesterone act synergistically in the development of adenomyosis after pituitary grafting. An increase in circulating prolactin concentration may be the most important factor for genesis of adenomyosis in the pituitarygrafted model. Further studies on the sequential changes in circulating hormone values are needed in the rat model.
    Classification of Mori and Nagasawa:
Grade 1: endometrial stromal cells present in inner layer of myometrium
Grade 2: endom. glands and stromal cells in inner layer of myometrium
Grade 3: endom. tissues present between inner & outer layers of myometrium
Grade 4: endom. tissues reach subserosa & protrude outside uterus as subserosal nodules.
Questions:
1) Define internal endometriosis
2) Define external endometriosis
3) _______ is a potent inducer of progesterone secretion via stimulation of ovarian corpora lutea.
a) Estrogen
b) Luteinizing hormone
c) FSH
d) Prolactin
4) True or False: The most striking ultrastructural change of the myometrium in rats with adenomyosis was the hyperplasia of the muscle cells of the inner layer bundles.
Answers:
1) AKA Uterine Adenomyosis: the presence of endometrial components (glands, stroma) in the myometrium.
2) The presence of endometrial tissues in the regions outside the uterine body.
3) dprolactin
4) False: The most striking...was the INVOLUTION of the muscle cells of the inner layer bundles.

Relationship Between Inspiratory Pressure and Tidal Volume in the Anesthetized Canine. Laboratory Animal Science 48 (1): 069.
    Ventilation based solely on tidal volume, without regard to lung inflation pressure, is inappropriate. Currently published veterinary guidelines for appropriate mechanical ventilation consist of a recommendation for tidal volume range based on body weight (1015 ml/kg), with little regard for peak lung inflation pressure (1525 cm H2O). In a preliminary survey, the authors found that tidal volume varied significantly with changes in peak lung inflation pressure and that, at the same pressure, animals of similar weight had widely varied tidal volumes. Mucous membrane color and capillary refill time appeared normal. However, blood gas or endtidal carbon dioxide values indicated underventilation in almost all of the animals ventilated.
    The authors then investigated the relationship between body weight, tidal volume, and inspiratory pressure delivered by the ventilator (lung inflation pressure) in anesthetized hounds. Lung inflation pressures were 10, 14, and 18 cm H2O. Physiologic variables were normal only when inflation pressure was 14 cm H2O. None of the measured physical variables accurately predicted tidal volume.
    These data suggest that the inconsistency in tidal volume is due to a previously undescribed variability in respiratory compliance in the anesthetized hound. Compliance and airway resistance are determined by thoracic morphology, respiratory tract disease or injury, and ventilationperfusion mismatches. These variables are dependent on factors such as anesthesia, ventilation, body temperature, and health status. Ventilatorinduced alveolar overdistention induces significant parenchymal lung injury, which can result in pulmonary edema, increased airway resistance, and decreased respiratory system compliance. At low lung inflation pressures, alveoli are underinflated, decreasing the available gas exchange area and resulting in increased dead space volume and decreased respiratory system compliance.
    Until new guidelines are established, endtidal or arterial carbon dioxide values for anesthetized canines should be monitored closely and ventilatory parameters should be adjusted to ensure proper ventilation. The authors' recommendations include: initiating ventilation at a pressure of approximately 1014 cm H2O; monitoring arterial carbon dioxide and oxygenation (blood gas tensions or pulse oximetry and capnometry); and adjusting lung inflation pressure to vary tidal volume to maintain normal PaCO2 and PaO2.
Questions:
1) The Harvard apparatus is a _________ ventilator.
a) constant volume, variable pressure
b) constantpressure volume
c) variable pressure
d) variable volume, variable pressure
2) True or False: The Ohio ventilator is a constantpressure volume ventilator.
Answers:
1) b
2) False: it is a variable pressure ventilator. The Harvard respirator is a constantpressure volume ventilator.

Effect of In Vivo Administration of All Trans-Retinoic Acid on the Hemopoietic Cell Populations of the Spleen and Bone Marrow: Profound Strain Differences Between A/J and C57BL/6J Mice. Laboratory Animal Science 48 (1): 074.
ATRA (All Trans Retinoic Acid) is a natural metabolite of retinol. Retinoids modulate gene expression in normal cells and they are being explored as adjuncts to chemotherapy, especially for leukemias. ATRA influences the growth and development of some cells in vitro by binding intracellularly to nuclear receptors, controlling transcription of genes.
        A/J mice are susceptible to leukemias and lymphomas. Their immune cells have lower anti-tumor activity and the mice (relative to C57BL/6J mice) are more susceptible to pathogens.
        Hypotheses: There are fewer immunity-mediating cells readily available in the spleen and bone marrow of A/J mice AND it may be possible to boost the numbers of the differentiated forms by administering ATRA orally.
        ATRA was administered in corn oil to A/J and C57 mice by gavage SID for 5 days. Control mice were given corn oil only. Mice were killed 24h after final dose. Spleen and bone marrow cells were collected, enumerated and identified. Lymphoid and granuloid lineages were grouped according to size and stage of maturity.
        ATRA treatment: Comparisons to control mice not always mentioned.
A/J mice --lower total cellularity in the spleen and BM than C57 (already reported)
        All cell lineages involved in immunity contributed to low cellularity
        Erythroid cells were similar in both organs to C57 mice
        Within each strain, the total cellularity was not affected by ATRA treatment in the spleen and bone marrow after 5 d. Subpopulations did change:
   A/J mice -Increase of immature granuloid cells in BM. Decrease of mature granuloid cells in BM. (Did ATRA block differentiation of just drive the mature cells out of the BM?) Comparable numbers in spleen of both strains.
   A/J mice -- Increased numbers of small lymphocytes in BM
   -- Decreased numbers of large lymphoid cells in spleen (clones of secondary production, not from BM so ATRA may be inhibiting the spleen based lymphoid population or driving these cells out of the spleen to peripheral locations).
        Both strains--Numbers of monocytes were significantly lower in BM and spleen of ATRA treated mice (Major function of retinoic acid is to drive monocyte differentiation and activation so these cells were most likely relocated and transformed into tissue macrophages)
Questions:
1) Which strain of mice have an unusually high frequency of leukemia?
        a) BALB/C
        b) C3H/HeN
        c) A/J
        d) C57BL/6J
2) All Trans Retinoic Acid
        a) inhibits cytokine synthesis
        b) inhibits chemotaxis
        c) drives monocyte differentiation and activation
        d) all of the above
Answers: 1) c     2) d

Effects of Feeding a Liquid Diet for One Year to New Zealand White Rabbits. Laboratory Animal Science 48 (1): 081.
Some nutritional and toxicological studies require the feeding of liquid diets to laboratory animals. This study was designed to investigate the long - term effects of a liquid diet on New Zealand White rabbits.
Results:
    Body weight gains were similar between the liquid- and dry-fed groups. The following differences were observed: 1) Female rabbits (regardless of diet type) had higher Plasma cholesterol concentrations compared to the male rabbits. 2) Plasma phospholipid concentrations were higher in the dry- fed rabbits compared to the liquid-fed rabbits. 3) Liquid-fed female rabbits had increased plasma triglyceride concentrations compared to the control group and liquid-fed males.
     After 52 weeks, the liquid-fed rabbits did not show clinical or biochemical evidence of liver disease.
QUESTIONS:
#1 When the diet is deficient in cholesterol, which protein causes hypercholesterolemia in rabbits?
        a.    Soybean
        b.    Casein
        c.    Beef
        d.    Fish
#2 What is the genus and species of the New Zealand White
Rabbit:_________________________
#3 List 3 Biochemical markers of liver function:
        __________________
        __________________
        __________________
ANSWERS:
#1 b
#2 Oryctolagus cuniculus
#3 ALT, AST, ALKP, BUN, and Albumin

Comparison of Four Diagnostic Methods for Detection of Helicobacter Species in Laboratory Mice. Laboratory Animal Science 48 (1): 085.
Four species of Helicobacter have been identified in the gastro intestinal tract of rodents and the PCR method wasthe most sensitive in detecting murine Helicobacter species.
Helicobacter muridarum, H rappini, H. hepaticus and H. bilis are common colonizers of the gastrointestibal tract. Tha pathogenic potential of the murine Helicobacter is unclrear ( gastritis, hepatitis, liver tumors...).Accurated diagnosis of Helicobacter infections is needed to assess the pathogenic potential of these organism to answers concers about their impact on research results and to determine the prevalence of Helicobacter species
In this study four differents methos for detection of Helicobacter species in the mouse intestinal tract were compared: polymerasa chain reaction (PCR), bacterial culture., electron microscopy and histologic examination. PCR: bacteria were isolated from cecal and fecal specimens and 35/ 40, 87,5 had concordant results. PCR versus culture of cecal species had 83% concordance. By SEM (scaning electron micoscopy) the only species of Helicobacter detected was H hepaticus with a 66% concordance. Histological analysis with a Steiner stain was not able to differentation between Helicobacter species and It was 81,8 %concordance. PCR was more sensitive than bacterial culture, electron microscopy and histological examination and PCR method can be performed using feces as a noninvasive menas for rapidly screening large numbers of colony mice for murine Helicobacter infections.
QUESTIONS
1.-Where can you find Helicobacter in mice.T/F
a. liver
b. illeum
c. stomac
d. gastrointestinal tract
2.- Method performed for screening large number of colony
ANSWERS
1.- c
2.- PCR using feces

Diagnostic Exercise: Vascular Endothelial Lesions in Athymic nu/nu Mice. Laboratory Animal Science 48 (1): 092.
History- 40 balb/c-Hfh11nu/Hfh11nu, housed in restricted area barrier maintained colony, subcutaneously injected w/neuroblastoma cell line. Six weeks later 7 mice were exhibiting weight loss, and 3 died unexpectedly. Three affected animals were necropsied. No gross post mortems lesions, aerobic lung culture negative,.
Pathology- Several large multinucleated syncytial cells were present in the vascular endothelium of ling, heart and kidney., more prevalent in arteries than veins.
Diagnosis and discussion
Differential Diagnosis for multinucleated syncytial cells in the mouse- MHV, Sendai, EDIM, and mycoplasmosis.
Syncytial cells were in the vascular endothelium have been associated w/MHV and must be differentiated from vascular endothelial cell hypertrophy, including K virus and ectromelia. Protozoan parasites such as Sarcocystis muris have a stage of their life cycle in endothelial cell which could resemble syncytial cells.
Serology on sentinel animals ?MHV positive, negative for other commonly tested pathogens.
    MHV is a coronavirus, numerous antigenicly relayed strains w/ greatvariability in their tissue tropism and virulence Loosely classified into two types- enterotropic and respiratory tropic.
Enterotropic- selectively infect intestinal mucosa w/ little dissemination to other target tissues.
    Respiratory- most strains, initial replication in nasal epithelium and then disseminates via lymphatics and blood. Pulmonary involvement is restricted to the vascular endothelium and does not involve the respiratory mucosa
    Clinical consequences in immune compromised animals depend largely on the strain- respiratory strains may result in progressively fatal multi systemic infections or chronic wasting, depending on virulence. Immune compromised animals infected w/ enterotropic strains may develop chronic enteric infections but do not exhibit clinically apparent disease.
    Cell line was tested and found to be free of MHV, supposed mode of transmission was contamination from another room w/ MHV positive animals.
Questions
1. Differential diagnosis for syncytial cell formation
2. Most MHV strains are enterotropic/respiratory tropic, and enterotropic/respiratory tropic are more likely to be lethal in immune compromised animals.
Answers.
1. MHV, Sendai, EDIM, and mycoplasmosis.
2. respiratory tropic, respiratory tropic

Progressive necrotizing dermatitis of the pinna in outbred mice: an institutional survey. Laboratory Animal Science 48 (1): 095.
This article summarizes a survey of lesions of ears caused by necrosis of the ear pinna in Charles River Laboratory (CRL) Crl:CD1(ICR) BR mice that sometimes causes ulcerative dermatitis down the neck and over the shoulders. The lesions initially appear focally on the dorsum of the pinna, resemble engorged blood vessels and is very subtle. Then serum begins to ooze from the site with an increase in inflammatory infiltrate. If the lesion progresses, peripheral necrosis begins and results in a necrotic area sloughing in a few days leaving a notched pinna. In a small proportion of animals the lesion progresses and the site becomes secondarily infected resulting in intense pruritis possibly resulting in self trauma to the area adjacent to the pinna. Grossly thickened ears histologically have epidermal hyperplasia, hyperkeratosis, and increased cellularity of the dermis. (Definitely look at pictures on this article). Surveys of 14 institutions yielded 26 studies with affected mice of which the incidence ranged from 2% to 42% usually in mice older than 14 wks. beginning at 913 wks.; 16 studies had a preponderance of males affected; 92% were singly housed in stainless steel wirebottom cages. Bacteria isolated from lesions were primarily Staphylococcus aureus with one group D Streptococcus. No etiology was found and treatment was not effective. Vascular ischemia and neurogenic abnormalities (preliminary studies in CD1 mice have indicated physiologic and anatomic defects in the auditory system) are being investigated.
Question:
What is the only other lesion reported in the literature that looks similar to this?
Answer:
Immune complex vasculitis with secondary ulcerative dermatitis in aged (20 months) C57BL/6NNia mice (leukocytoclastic vasculitis from deposition of immune complexes)

Detection and typing of lactate dehydrogenaseelevating virus RNA from transplantable tumor, mouse liver tissues, and cell lines, using polymerase chain reaction. Laboratory Animal Science 48 (1): 099.
Lactate dehydrogenaseelevating virus (LDV) is and RNA virus of the Togaviridae family in the genus Arterivirus. It is a murine virus that establishes lifelong viremia and asymptomatic infection in mice. It modulates host reaction against immunologic stimuli and induces rapid and persistent elevation of lactic dehydrogenase activity in plasma. The most frequent source for infection in mice is transplantable tumors or other biologic materials. Viral infection is usually detected by elevation of the enzyme in plasma because antibody response is poor in infected mice. cDNA of NLDV strain was amplified from open reading frame sequences of strains LDVC and LDVP. 48 tumors, 5 mouse liver tissues, and 123 cell lines were derived from 8, 5 and 28 facilities. RNA from the specimens was extracted. Patterns of restriction enzyme cleavage for each of the 3 LDV strains was used to distinguish the 3 strains. 14/48 (29.2%) tumors derived from 3/8 (37.5%) facilities and 2/5 (40%) liver specimens derived from 2/5 (40%) facilities were positive for LDV RNA but the virus was not detected in any of the 123 cell lines tested. The LDVP strain was found to be the most common contaminant in Japan. PCR and restriction analysis described are suitable not only for detection of LDV contamination in transplantable tumors, mouse liver tissues and cell lines, but also for typing of the virus strains.
Question: How can LDV be eliminated from LDVcontaminated tumors?
Answer: LDV can be eliminated from tumors by passage of tumor cells in a rodent species other than the mouse or by maintenance of tumor cells in tissue culture because the virus can propagate only in mice and primary cell cultures of mice.

New Method for Genotyping the Mouse Lepob Mutation, Using a Polymerase Chain Reaction Assay. Laboratory Animal Science 48 (1): 103.
This study established a PCR assay to be a one step assay to identify mice for autosomal recessive mutation (Lepob/Lepob) which are severely obese and have noninsulin-dependent diabetes mellitis (NIDDM. Previous testing consisted of a two-step process of PCR and detection of fragment length polymorphism (RFLP).
    This normal gene produces leptin, when injected into mice decreases food intake, body weight, increased energy expendature and alleviation of sterility. These animals are not visually obese before 25 to 28 days of age. Heterozygous mice (+/Lepob) cannot be distinguished from homozygous mutant (Lepob/Lepob) or wild caught (+/+) homozyous. A 100 bp primer set was established for the three genotypes listed above.
    PCR results were confirmed with monganomous breedings of heterozygous (+/Lepob) males and females from the three identified 100 bp primer sets with an expected 1:4 ratio (Lepob/Lepob to +/Lepob). A second breeding of heterozygous males and females did not produce any obese mice.
Questions:
1.      Lepob/Lepob mice are not visually obese before_________and do not produce adequate levels of__________?
2.      The new assay consists of______________and consisting of_____________?
Answers:
1.      25 to 28 days; leptin
2.      a single PCR test; consisting of 100 bp primer sets.