Viral Infections of Nonhuman Primates. Laboratory Animal Science 47 (5): 461.
Results from 53,000 serologic tests and viral isolation studies submitted to Virus Reference Laboratory, Inc are summarized.
Highlights include:
More chimpanzees and gorillas were seropositive to human HSV-1, HSV-2, and V-Z virus than were organgutans and gibbons. Positive reactivity to CMV and EBV were found in each of these species. Chimpanzees had the highest incidence of Hepatitis A and B reactivity.
13.7% of the macaque serum samples were positive for herpes B virus. Other viruses giving a relatively high percentage (40-98%) positive serum titres in macaques include: CMV, EBV, measles virus, Hep A, SRV, foamy virus, SV40, SA 11.
When compared to other macaques, the rhesus tested significantly higher for adenovirus.
Baboons tested positive for SA6, EBV, SA8, and measles and were rarely positive for B virus.
Squirrel monkeys had antibodies to H. tamarinus and H. saimiri (about 20%). Squirrel monkey CMV antibody was present in about 50% of all of the New World Primates tested.
See table for complete listing of anti-viruses antibodies analyzed and percentages of species scoring positive reactions.
Questions:
1. Positive Adenovirus titres are most common in which one of the following:
A: Cynomologous
B: Rhesus
C: Pig-tail
D: Stump-tail
2. Why is the information presented in this manuscript important ?
3. The shape of an electron micrograph of a monkeypox virus could best be described as:
A: circular
B: oval
C: cigar-shaped
D: square
4. In which of the following species would you most likely find a positive titre to B virus:
A. Macaques
B. Baboons
C. Vervets
D. Chimpanzees
5. The prevelance for positive B virus samples reported here was significantly decreased from a previous report. Why might this be so?
Questions:
1. Serologic samples that are sent to a diagnostic laboratory generally need
to be sent on dry ice? T or F
2. A positive Epstein-Barr virus titer is not frequently found in nonhuman
primates? T or F
3. Viral isolation is an easy procedure that has a low false negative result?
T or F
Answers:
1. B
2. Important for developing models of human viral infection. Important for selection of animals in the use of xenotransplantation. Provides insights for establishing a risk assesment and for developing a plan for monitoring of disease in a colony. May provide insights as to the prevelance of specific zoonotic diseases in defining husbandry practices and policy development.
3. A: see cover of this issue, 47(5)
4. A. 13.7% tested positive
5. The authors speculate that this may be a reflection of recent selective breeding strategies and stringent colony management practices aimed at producing B virus
Answers:
1. F
2. F
3. F

Detection of Urogenital Mycoplasmal Infections in Primates by Use of Polymerase Chain Reaction. Laboratory Animal Science 47 (5): 468.
232 specimens were obtained from 166 primates (Macaca fascicularis, M. mulata, M. nemistrina, Papio sp., and Pan troglodytes). All healthy animals wee anesthetized. Vaginal, cervical, or endometrial swabs were taken from females and urethral swabs were taken from males. The swabs were tested for Ureaplasma urealyticum, Mycoplasma hominis, and Mycoplasma genitalium-all of which are considered to be human urogenital mycoplasmas. These organisms were identified by polymerase chain reaction (PCR). "Specific PCR indicated that M genitalium was significantly less common that M. hominis and U. urealyticum" but all were observed in the species studied. Positive "generic" PCR results may be the result of other types of mycoplasma present.
Mycoplasmas may play a role in decreased fertility/low birth rates of some primate colonies. Also primates may be an important animal model for human urogenital mycoplasma infections.
Question:
What is the advantage of using PCR to identify mycoplasma sp.?
Answer:
Mycoplasma culture methods are less sensitive and subject to inhibition by antibiotics. They also may require weeks for results.

Five Spontaneous Deaths Associated with Clostridium difficile in a Colony of Cotton-Top Tamarins (Saguinus oedipus). Laboratory Animal Science 47 (5): 472.
Clostridium difficile is a gram-positive, anaerobic, spore-forming bacillus. C. difficile can be found in the GI tract of most mammals and the environment. Under normal conditions, C. difficile dose not cause clinical disease. However, antibiotic - induced changes in the GI microflora may promote C. difficile proliferation and toxin production. C. Difficile uses a fecal-oral route of transmission.. This bacterium produces resistant spores that promote environmental contamination and bacterial transmission
C. difficile causes pseudomembranous colitis in humans. Most human infections are associated with antibiotic therapy. Common clinical findings in people are watery or mucoid diarrhea (+\- hematochezia), pyrexia, abdominal pain, and a leukocytosis. Diagnosis of C. difficile in humans requires the following information: history of antibiotic use, clinical signs, endoscopy, and detection of C. difficile toxin in the feces. Enteric cultures should be interpreted with caution, since most mammals may carry C. difficile in their GI tracts. Vancomycin and metronidazole are the antibiotics of choice for the treating C. dificile infections in humans.
This case-report suggested that antibiotic induced colitis and diarrhea may be associated with C. difficile infection in Cotton-Top Tamarins. A colony Tamarins was treated with antibiotics (erythromycin or norfloxacin) following an outbreak of diarrhea. A Campylobacter spp. was cultured from most of the affected animals prior to antibiotic therapy. This colony of received antibiotics in the past to control cyclical episodes of diarrhea attributed to Campylobacter infections. Five Tamarins died spontaneously following a recent antibiotic treatment. The deaths ranged from 9 to 38 days post antibiotic therapy. Weight loss, diarrhea, hematochezia, weakness, and sudden collapse were some of the clinical signs seen prior to death. Two Tamarins had histological evidence of a pseudomembranous colitis. The clinical signs, history of antibiotic therapy, evidence of C. dificile toxin, and the presence of pseudomembranous colitis suggested that C. difficile was the etiologic agent.
QUESTIONS:
1. Which antibiotics are MOST frequently associated with psuedomembranous colitis in people:
a. clindamycin
b. baytril
c. ampicillin
d. cephalosporins
e. a,b, and c
f. a,c, and d
g. a and c
2. (T or F) In the Syrian hamster model, pseudomembranes are a common histological finding.
3. In captivity, Cotton-Top Tammarins have a high incidence of spontaneous ________ associated with _________ of the colon.
ANSWERS:
1. f (These antibiotics have bee implicated more frequently in causing C. dificile infections in people; however, all oral antibiotics have the potential to promote C. dificile infections.)
2. False (Pseudomembranes, which are common in the human disease, are seen less frequently in the Syrian hamster)
3. colitis, adenocarcinoma

Anthelmintic Treatment to Eradicate Cutaneous Capillariasis in a Colonly of South African Clawed Frogs (Xenopus laevis). Laboratory Animal Science 47 (5): 477.
This nematode, a skin parasite, is common in laboratory facilities with prevalence >30% in wild caught frogs, as well as those bred in captivity. Frogs are asymtomatic until stressed. Dorsally, the skin becomes gray and rough;ventrally, it is reddish brown. Skin scrpings are used identify eggs, adults and skin tunnels. Ivermectin orally and injection (dorsal lymph sac) did not eliminate the parasite. Ivermectin-medicated tank water is not feasible due to its low solubity in water. Elimination of the parasite was reiably achieved by the use of levamisole-medicated tank water after two treatments 10 to 14 days apart.
Questions: T or F
1. A mono operculated egg found on X. laevis skin scraping would be Capillaria.
2. The life cycle of C. xenopodis is direct.
3. Levamisole is a immunostimulant.
Answers: 1. F 2. T 3.T

Endothelial-Target Rickettsial Infection. Laboratory Animal Science 47 (5): 483.
Rickettsia conorii infection of C3H/HeN mice provides and animal model for the human disease, Boutonneuse fever (Mediterranean Spotted Fever)
The C3H/HeN endothelial target mouse model is produced by intravenous inoculation of adult mice with viable R. conorii. The incubation period is dosage dependent. Plaque forming units of rickettsiae can cause death (high number of plaques) or overt illness from which the mice recover (lower number of plaques). Recovery is associated with intracellular destruction within endothelium, macrophages and hepatocytes.
Pathological lesions from IV inoculation are similar to those in human Boutonneuse fever except for the cutaneous inoculation site eschar: Endothelial injury, cellular immune response, histopathology of vascular lesions, meningoencephalitis, interstitial pneumonia and outcome of either fatal or immune clearance of organisms.
Day 3--swollen endothelial cells and mononuclear cell margination multifocal necrosis of single hepatocytes and accumulation of many mononuclear cells and a few PMNs
Day 5--Multifocal hepatic granulomas; Perivascular lymphohistiocytic infiltrates (stimulate nitric oxide-dependent rickettsial killing) in the brain, meninges, lungs, heart, testicular adnexa and others
Day 15-disappearance of hepatic granulomas; maintenance of infiltrates and evidence of perivascular edema
Other rickettsial organisms such as Ehrlichia, Coxiella, and Bartonella have different cellular targets and lifestyles and this is not an accurate animal model for their diseases.
Questions:
1. Rickettsia conorii infection of C3H/HeN mice is a suitable animal model for what human disease?
a. Rocky Mountain Spotted Fever
b. Boutonneuse fever
c. Israeli spotted fever
d. all the above
Pathologic features of Endothelial-Target Rickettsial Infection do NOT include:
a. Multifocal necrosis of single hepatocytes
b. Eosinophilic meningoencephalitis
c. Swollen endothelial cells
d. Interstitial pneumonia
Answers:
1) D 2) B

Cardiac Troponin T is a Sensitive, Specific Biomarker of Cardiac Injury in Laboratory Animals. Laboratory Animal Science 47 (5): 486.
Serum creatine kinase (CK) and lactate dehydrogenase (LD) are used effectively as indicators of myocardial injury in people. Due to the restricted sensitivity and specificity, these assays provide limited information on cardiac injury in laboratory animals. A more specific and sensitive immunologic method has been developed for the detection of cardiac injury in people. The assay relies on the immunodetection of a protein called cardiac troponin T (cTnT). Troponin T is a myofibrillar protein principally involved striated muscle contraction. Despite the high sensitivity of this immunoassay, some investigators question the specificity of the test. Recent reports indicate that uremia, multi-organ disease, and muscle injury caused increases in cTnT.
This experiment focused on determining the applicability of cTnT in detecting cardiac injury in laboratory animals. Results from canine and rat models of myocardial infarction demonstrated 1,000- to 10,000 - fold increases in cTnT concentrations. In these models, A high correlation was demonstrated between cTnT concentrations and infarct size 3 hours post infarct. The effectiveness of CK and LD as indicators of cardiac injury were less compared to cTnT, especially in the presence of moderate skeletal muscle injury. In addition to cardiac infarcts, cTnT levels detected cardiac injury following cardiac puncture in ferrets and doxorubicin-induced cardiotoxicosis in mice.
QUESTIONS:
1) Define Diagnostic Sensitivity: _________________________
2) Define Diagnostic Specificity: __________________________
3) cTnT is an effective biomarker for the evaluation of cardiac injury in the presence of _________ muscle injury.
a. mild
b. moderate
c. severe
d. a & c
e. a & b
f. none of the above
ANSWERS:
1. sensitivity = TP/TP+FN TP= true positive, FN = false negative
The probability of a positive test given disease
2. specificity = TN/TN+FP TN = true negative, FP = false positive
The probability of a negative test given the absence of disease
3. E

Cryopreservation of Murine Zygotes for Use in Testing Culture Environments. Laboratory Animal Science 47 (5): 496.
The purpose of the study reported here was to refine freezing techniques to provide easy access to one-cell zygotes for in vitro fertilization (IVF) environment. B6C3F1/HSD female mice were injected IP with PMSG followed 47 hours later with HCG. The female mice were bred with B602F1/HSD males and zygotes were collected at 23 and 29 hours for 1-celled zygotes and 43 hours for 2-celled embryos. Zygotes were collected in MZ medium containing BSA and transferred to 2m ethylene glycol and loaded into 0.25ml straws, frozen slowly at -0.5 degrees C/min to -40.0 degrees C before plunging into liquid nitrogen and left for five days. Straws were equilibrated for 2 minutes at room temperature followed by a 3 minute warming in a 37 degree C water bath.
Zygotes were examined for freeze-thaw damage after being cultured in mHFT and humidifed in 5% CO2/5%O2/90%N2 at 37%. There are a large number of applications of successful cryopreservation methods for one-celled mouse embryos.
Questions:
1. The most common freeze-thawed damage occurs in the form of?
2. This freeze-thaw damage is prevented by?
Answers:
1. Fractured zona pellucida and blastomeres.
2. The use of plastic straws and optimization of freezing and warming conditions.

Housing and Exercise of Dogs: Effects on Behavior, Immune Function and Cortisol Concentration. Laboratory Animal Science 47 (5): 500.
This study was designed to determine whether opportunity for exercise individually or with a conspecific is beneficial to research dogs in terms of effects on physiologic and behavioral measures designed to assess general wellbeing. Neuroendocrine (plasma cortisol), immune (humoral immunity), and behavioral (videotape) responses were assessed in four groups of dogs: exercised individually (EI), exercised with a conspecific (EC), nonexercised (NE), and cage control (CC). The duration of the study (12 weeks) was determined based upon a previous study that indicated dogs housed under conditions of relative social isolation for 3 months exhibited increased stereotypies and evidence of separation distress.
Glucocorticosteroid values are generally considered poor indicators of longterm stress because they usually return to baseline values within the first few days after an initial stimulus. The only behavioral measure significantly affected by treatment condition was barking, which occurred more frequently in exercised dogs. This study indicates that wellbeing may not be improved by providing dogs an opportunity for outofcage exercise.
Psychoneuroimmunology (PNI) is the study of the intricate interaction of consciousness (psycho), brain and central nervous system (neuro), the neuroendocrine system, and the body's defense against external infection and internal aberrant cell division (immunology)or, more generally, the relationship between the psychologic state and biologic disease processes. One working hypothesis of PNI is that stress activates the neuroendocrine system, which in turn is associated with changes in behavior and immune function. Advances in the field of PNI and stress research may provide valuable insight into physical and psychosocial wellbeing of laboratory animals.
Note: See pages 502503 (Tables 13) for descriptions of normal and aberrant behaviors.
Questions:
1) True or False: Glucocorticosteroid values are reliable indicators of chronic stress in laboratory animals.
2) What is the name of the field that studies the relationship between the psychologic state and biologic disease processes?
3) In what year was PL99198 passed? What did it require?
Answers:
1) False
2) Psychoneuroimmunology (PNI)
3) 1985; Minimal standards for exercise of dogs to be established by the USDA.

Light Contamination During the Dark Phase in "Photoperiodically Controlled" Animal Rooms: Effect on Tumor Growth and Metabolism in Rats. Laboratory Animal Science 47 (5): 511.
Tumor growth and metabolism are enhanced in animals maintained in a constant light (24L:0D) environment. Increased tumor growth is directly dependent on increased ambient plasma concentration of plasma total fatty acids (TFA), particularly linoleic acid (LA), an essential fatty acid critical for tumor growth. Linoleic acid is taken up by tumors and converted to the putative mitogenic transduction molecule 13hydroxyoctadecadienic acid (13HODE), which stimulates tumor growth. Linoleic acid utilization and 13HODE production are suppressed by the circadian neurohormone melatonin (Nacetyl5methoxytryptamine), which is secreted by the pineal gland.
In this study, male Buffalo rats BUF (BUF/Ncr) were randomized into three groups: Group I (12L:12D), Group II (12L:12h lightcontaminated [0.2 lux] dark phase), and Group III (24L:0D). Groups I and II had daily cycles in TFA and LA, whereas Group III had constant values throughout the day. Amplitude of the nocturnal melatonin surge was suppressed in Group II; circadian variation in melatonin concentration was not seen in Group III. Latency to onset of palpable tumor mass of implanted Morris hepatoma 7288CTC was markedly increased in Group II and Group III. Production of 13HODE by the hepatomas was markedly increased in Group II and Group III. Minimal light contamination of only 0.2 lux during an otherwise normal dark phase inhibits host melatonin secretion and increases the rate of tumor growth and lipid uptake and metabolism. Great care must be taken to prevent "lightleaks" in an animal room during the dark phase of the diurnal cycle. Such contamination may adversely affect the outcome of tumor growth investigation.
Questions:
1) Where are circadian rhythms generated?
2) How is tumor weight estimated?
3) What is the ratelimiting enzyme for melatonin synthesis?
4) The synchronizing signal to the Suprachiasmatic Nucleus is:
a) blue light
b) bluegreen light
c) red light
d) violet light
e) white light
Answers:
1) The Suprachiasmatic Nucleus (in the anterior portion of the hypothalamus)
2) Method of Sauer: measurements are made through the skin, using calipers (brief description on page 513).
3) Nacetyltransferase
4) b: bluegreen light

Prolonged (12 Hours) Anesthesia in the Rat. Laboratory Animal Science 47 (5): 519.
A method is described for prolonged anesthesia in the rat with subsequent recovery. Initial anesthesia was obtained by intramuscular injection of 37 mg of ketamine/kg of body weight and 7 mg of xylazine/kg (equal volumes of ketamine [100mg/ml] and xylazine [20mg/ml] mixed and injected into the lateral thigh muscles. Intravenous anesthetic was prepared by mixing 0.5 ml of ketamine (100mg/ml) and 0.08 ml of xylazine [20mg/ml] in 9.5 ml of 2.5% dextrose-0.45% sodium chloride (a 30:1 ratio of ketamine:xylazine). The solution was administered into an intravenous (jugular vein) catheter with a Model 22 Syringe Pump (Howard Apparatus Co., South Natick, Mass).
The rate of anesthetic infusion was adjusted to keep the respiratory rate between 70 and 100 breaths/min (40 to 50 ul/min) which was adequate to maintain a satisfactory depth of anesthesia (lack of a positive paw-withdrawal reflex). After anesthetic administration was discontinued at the end of the 12 hour period, the righting reflex was regained within a few hours.
Questions:
1. Ketamine causes:
a. stimulation of the cardiovascular system
b. increased heart rate, blood pressure, cardiac output and central venous pressure
c. bronchiodilation
d. a and c only
e. a, b, and c
2. T or F: Xylaxine has been reported to cause hypoglycemia in rats.
3. Prolonged anesthesia as achieved in this study was more successful when the rats rectal temperatures were maintained between what temperatures?
a. 35 - 36 C
b. 36 - 37 C
c. 37 - 38 C
d. 38 - 39 C
e. 39 - 40 C
4. Relative to the shape of the oxyhemoglobin dissociation curve, oxygen delivery to tissues is not significantly reduced until PO2 decreases to what level?
Answers:
1. e (a, b, & c)
2. F. Xylazine has been reported to cause hyperglycemia in rats, but a trend towards hypoglycemia was noted during prolonged anesthesia in the rats of this study.
3. a (35 -36 C)
4. When PO2 decreases to <60 mmHg

Appearance of Morphologically Abnormal Sertoli Cells in Infertile PD Male Rats During Postnatal Development. Laboratory Animal Science 47 (5): 524.
This study evaluated the Sertoli cells in the PD strain of rats at 7 and 21 days. The P/D rat is characterized by an autosomal recessive gene (pd) that causes polydactalism in the forelimb and the hindlimbs. Female pd/pd rats can produce offspring but males cannot. Sertoli cells were observed at 7 days in pd/pd males and noted to have light and dark cells but no abnormal cells. Dark cells observed at 7 days were not observed at 21 days. Only light and abnormal sertoli cells were observed in 21 day old pd/pd male rats. The abnormal cells had irregular shaped nuclei and a large quanity of lipid droplets in the cytoplasm. The abnormal cells accounted for 11% of the cells in the pd/pd male rats and were half that many in the male pd/+ control rats. This small percentage of abnormal cells were considered to be possible degenerative remains of the dark cells observed at 7 days.
No questions

Hematologic and Serum Biochemical and Electrolyte Values in Clinically Normal Domestically Bred Rhesus Monkeys (Macaca mulatta) According to Age, Sex, and Gravidity. Laboratory Animal Science 47 (5): 528.
The article provides a set of blood values for clinically normal, domestically reared rhesus monkeys of different age, sex, and gravidity. Blood was collected from 251 nongravid females, 97 gravid females and 179 males. Date of birth and pedigree were known for all animals. The following hematologic and biochemical values were obtained:

HCT HGB WBC RBC
MCV MCH MCHC Bili
ALT AST ALP CR
GLU BUN TP ALB
GLOB CHOL GGT TRIGLY
Ca P CK LD
UA Cl Na K

Significant differences by age were observed, as well as between sexes and gravidity. An interaction between age and gravidity was also observed for some of the values tested.
For those using rhesus monkeys, excellent charts showing the values obtained by age, sex and pregnancy. However, it didn't list the stage of pregnancy at which values were obtained.
No questions.

Neoplastic Mass of the Vagina and Vulva in a Dog. Laboratory Animal Science 47 (5): 534.
This case report details the detection and histopathologic evaluation of a Canine Transmissible Venereal Tumor (CTVT) in an adult mixed breed bitch. This tumor was 10cm x 10cm, multilobulated and friable and protruded from the vulva.
CTVT's are round cell tumors of reticuloendothelial origin and are transmitted by transplantation of viable tumor cells during coitus. Oncogenic viral particles have not been observed. These tumors can affect the external genitalia of either sex.
Currently, the most effective treatment of CTVT appears to be chemotherapy using Vincristine weekly for 4-6 weeks. Surgical excision has also been used successfully but reoccurrence is more common. Metastasis is uncommon. Left untreated, these tumors may spontaneously regress.
Questions.
1. T/F Canine Transmissible Venereal Tumors are only seen in female dogs.
2. T/F Canine Transmissible Venereal Tumors are transmitted by an oncogenic virus.
3. Name the Genus and species for the dog.
Answers
1. False. CTVT's can be seen on the external genitalia of either sex.
2. False. CTVT's are transmitted by transplantation of viable tumor cells and not by a virus.
3. Canis familiaris

Use of Endoscpic and Ultrasound Techniques in the Guinea Pig Leiomyoma Model. Laboratory Animal Science 47 (5): 537.
This study explained the use of ultrasound and endoscopy in evaluating the presence of leiomyomas in the guinea pig . Five animals were ovariectomized and divide into two groups. Three that were not exposed to E2( estradiol-17B) and two that were exposed. The implants were removed after 4 months. All the animals were followed a total of 9 months. All the OVX animals that were treated with E2 developed leiomyomas within 3 months, but the ones not treated did not. The leiomyomata were followed using ultrasound. Once formation was evident by ultrasound the guinea pigs were given and endoscopic examination with a 1.9 mm zero degree diagnostic endoscope through a supra umbilical incision. All the animals exposed to the E2 formed large spherical or sessile leomyomata primarily on the abdominal wall and small peduculated tumors on the surface of the uterus. There were no cardio pulmonary complications in the animals with pneumoperitoneum from the endoscopy even after being repeated 3 times over a five month period. No other complications were noted in association with the repeated endoscopic examinations. These less invasive/ non invasive techniques are very useful in the examination of abdominal leiomyomata in comparison to laparotomy. They not only reduce the stress, but the ultrasound allow the scientist to verify the tumor size before laparotomy.
Questions:
1. What is the gestation period of the guinea pig?
2. What are the signs of estrogen toxicity?
Answers:
1. 63 days
2. Bone marrow depression.

Multifocal Necrotizing Enteritis with Hepatic and Splenic Infarction Associated with Clostridium perfringens Type A in a Guinea Pig Raised in a Conventional Environment. Laboratory Animal Science 47 (5): 540.
This report describes a case of enteritis in a Guinea Pig caused by C. perfringens. The animal presented with lethargy and anorexia.
Necropsy revealed fibrinous adhesions of the small intestine and liver to the peritoneum, the liver was white and friable, surfaces of the ileum were covered with ecchymotic hemorrhages, 5 mls of pertioneal effusion was present.
Differential diagnosis: Salmonella spp., Yersinia pseudotuberculosis, C. piliforme (Tyzzers), C. perfringens and C. difficile.
Histology: acute, multifocal, severe, necrotizing, ulcerative ileitis and typhlitis. Brown and Brenn staining revealed large gram-pos rods with central subterminal spores.
Confirmation of C. perfringens: PCR was performed on paraffin embedded samples to test for presence of genes for alpha toxin, beta toxin, epsilon toxin, iota toxin and enterotoxin.
Results of CPR: alpha toxin present--this is present in all Clostridiums, but primers used here were unique for C. perfringens alpha toxin. Identity of PCR product was confirmed using restriction enzyme analysis verifying presence of EcoRV site in the PCR product.
Unfortunately, the organism was not cultured, which would have allowed fulfillment of Koch's postulates.
Questions:
Contrast the above findings with those typical for C. difficile
Answer:
1. C. difficile causes an enterotoxemia, so pathology generally confined to the intestinal tract.
2. Hepatic and splenic lesions are not typically seen (as were seen in this case).
3. Often associated with (or secondary to) antibiotic therapy

Speedy Backcrossing through In Vitro Fertilization, Using Pre-pubertal Superovulation and Neonatal Death Dependent on Genetic Background in Angiotensinogen-Deficient Mice. Laboratory Animal Science 47 (5): 545.
To accelerate the process of developing congenic mice, the authors utilized in vitro fertilization of oocytes collected by superovulation of prepubertal females. Specifically, a chimera with a targeted mutation of the angiotensinogen gene was mated with C57BL/6J mice. Female F1 animals that were heterozygous for the targeted angiotensinogen gene were superovulated with pregnant mare serum gonadotropin (25 days old) and human chorionic gonadotropin (27 days old). The collected oocytes were fertilized with spermatozoa from male C57BL/6J mice and subsequently 2-cell stage embryos were transferred into pseudopregnant ICR mice. The time required to backcross one generation by natural breeding compared to the time required for in vitro fertilization combined with prepubertal superovulation was on average 3 months/generation and 1.6 months/generation, respectively. The 8th backcrossed generation of heterozygous mice were mated to produce C57BL/6J angiotensinogen deficient homozygous mice. Of 72 mice offspring, 18 were homozygous mutants and all 18 homozygous mutants died in the neonatal period (less than 10 days old). This finding of neonatal death was in contrast to previous observations by the authors, whereby 11 of 15 homozygous mutants with a mixed genetic background survived past weaning.
Questions:
1. In the development of a congenic inbred strain with a mutation that is autosomal dominant or codominant, what mating system is commonly used? For a mutation that is recessive?
Answers:
1. Backcross, Cross-intercross

F344-rnu/rnu Athymic Rats: Breeding Performance and Acceptance of Subcutaneous and Intracranial Xenografts at Different Ages. Laboratory Animal Science 47 (5): 549.
Background
Female rnu/rnu rats are normally fertile and produce offspring, however, they can rear only a few newborn. To circumvent this problem, most facilities use heterozygous females rnu/+ bred to either homozygous rnu/rnu or heterozygous rnu/+ males.
The survival of xenographs in athymic rats is age dependent and could be attributed to the increasing number of T-cells at older ages. This article examines the use of athymic rats as a preferable model system for central nervous system xenografting. The objective was to compare four methods of breeding F344-rnu/rnu athymic rats. The authors compare the transplantability of tumor xenografts, subcutaneous and intracranial implantation, in homozygous and heterozygous athymic rats. Xenografts were cell lines of human and mouse origin.
Results
Male F344-rnu/rnu x female F344-rnu/+ was the optimal mating system producing the highest litter size and highest number of weaned pups per litter.
Tumor xenograft size was significantly larger is 9 month old nude rats than in 9 week old nude rats. Tumor xenografts grew in F344 rnu/rnu rats but did not grow in F344 rnu/+ rats when injected intracranially.
Conclusions
Mating male F344-rnu/rnu with female F344-rnu/rnu rats appears to be the optimal breeding system for nude rats. The poor mothering capability of nude rats is confirmed as well as the poor sucking ability of the dam. Tumor xenografts of human glioblastoma cells could be accepted subcutaneously and intracranially by homozygous nude rats but not heterozygous nude rats making them potentially useful in surgical organ xenotransplantation. The lack of xenotransplantation rejection in F344-rnu/rnu rats older than 9 months suggests they may be of use as a model of long-term xenotransplantation.
Questions:
1. The nude mutation is a
a. autosomal dominant
b. autosomal recessive
c. incomplete dominance
d. sex-linked recessive
2. Homozygous rnu/rnu rats are difficult to bred because
a. females are not compatible with males
b. females are not fertile
c. females produce a lower than normal litter size
d. females demonstrate poor maternity and suckling skills
3. The optimal breeding system for rnu/rnu rats was the following;
a. homozygous females and homozygous males
b. heterozygous females and homozygous males
c. heterozygous females and heterozygous males
d. homozygous males and homozygous females
Answers:
1. b
2. d
3. b

Mycotic Thromboses in Sheep Implanted with Biomedical Cardiac Devices. Laboratory Animal Science 47 (5): 554.
Infection of cardiovascular prosthese in human patients is a common complication. Open heart surgery is the most common predisposing factor to fungal endocarditis, which complicates up to 1% of all heart surgeries. This is a report of 3 sheep who developed systemic mycoses following implantation with the Penn State electric left ventricular assist device (2 sheep) or a Bjork-Shiley convexo-concave mitral valve. In all three sheep, thrombi formed along the grafted implants and caused failure of the devices. PAS was used to demonstrate fungal hyphae in the thrombi in all 3 sheep. One sheep was infected with Mucor spp., the other sheep with Aspergillus. In two sheep, embolization from the thrombi caused infarcts in the kidneys and small intestine.
The two sheep who received left heart assist devices were adequately anticoagulated by heparin during surgery followed by maintentance with oral warfarin, and the thrombi were deemed to be caused by the fungal infection. The authors believe that construction in the facility was responsible for increased environmental levels of fungi, and that prophylactic antibiotic treatment may also have increased the sheeps' susceptibility to fungal infections.
Questions:
1. What is PAS stain, and what biochemical compound does it stain?
2. What drug can be used to anatagonize heparin?
3. Would you want something called a Bjork-shiley convexo-concave mitral valve implanted in YOUR heart? Egads!
Answers:
1. Periodic acid Schiff. It stains carbohydrate, and is more usually used to stain things such as mucus in goblet cells, glycogen in the liver, etc.
2. protamine sulfate
3. :)