Previous studies have reported that housing rats and mice on softwood beddings induce microsomal enzymes. To date, no published studies investigate effects of softwood beddings on microsomal induction in rabbits. The purpose of this study was to determine whether microsomal enzymes, primarily cytochromes P450 3A and 2B, were induced in rabbits exposed to commonly used bedding substrates. Rabbits were placed in cages 7.6 cm above 1 sheet of 24×36 in. postconsumer recycled paper, approximately 16 cups (130 ounces) of pine shavings, or no substrate. Positive-control rabbits were given either rifampin (50 mg/kg) or phenobarbital (60 mg/kg) intraperitoneally once daily for 5 d. At 2, 7, and 14 d after placement in test cages, rabbits were euthanized and the livers harvested. Microsomal pellets were prepared from the livers and used in an erythromycin N-demethylase assay (to determine CYP3A activity) and a pentoxyresorufin-O-deethylation assay (to determine CYP2B activity). Although the levels of enzyme induction varied slightly in both assays, statistical significance was not reached compared to the positive-control levels. These results indicate that neither CYP450 3A or 2B enzymes are induced by exposure of rabbits to pine shavings or paper substrate as noncontact bedding for up to 14 d.

We evaluated the effects of buprenorphine (0.05 mg/kg intraperitoneally) after collagenase-induced intracerebral hemorrhage in Sprague-Dawley rats. Methods of evaluation included serum biochemistry, behavioral tests (neurologic exam and rotarod treadmill), and histopathology. Serum biochemistry parameters showed no change after surgery in controls and buprenorphine-treated animals. At 48 h after collagenase injections, the performance of treated rats on the rotarod treadmill test was not significantly different from that of untreated rats, but the neurologic exams of treated rats showed significantly improved performance. Although the volume of the hematoma was reduced with buprenorphine, the number of necrotic neurons in the penumbra was significantly increased. These data indicate that administration of buprenorphine led to neurologic and histopathologic differences in a rat model of intracerebral hemorrhage, and data from such studies should be interpreted carefully if an opioid analgesic is used to minimize pain.

Whether wild-caught animals used for biomedical research carry antibiotic-resistant bacteria is not well studied. Thirteen- lined ground squirrels (Spermophilus tridecemlineatus) are small mammals used to study hibernation. These animals are captured from the wild or are born in laboratory animal facilities to wild-caught mothers. Because microorganisms harbored by 13-lined ground squirrels may be pathogenic to their caretakers and other laboratory animals, learning more about antibiotic resistance in these animals could be useful. In this study, tetracycline- and chloramphenicol-resistant Morganella morganii and multidrug resistant Stenotrophomonas maltophilia were isolated from the ceca of four 13-lined ground squirrels. These findings support further study of antibiotic-resistant bacterial populations in wild-caught mammals used as laboratory models.

We investigated the effect of anesthesia on serum lipid parameters in adult bonnet macaques (Macaca radiata). We treated 10 animals with ketamine hydrochloride (15 mg/kg intramuscularly) and, on the next day, thiopentone sodium (25 mg/kg intravenously). Blood samples were obtained before and after anesthetic treatment. Serum cholesterol, triglycerides, very low-density lipoprotein (VLDL), and high-density lipoprotein (HDL) were measured by autoanalyzer. Ketamine anesthesia significantly decreased serum cholesterol and HDL levels, whereas thiopentone significantly reduced triglycerides and VLDL and increased HDL values. Although the effects of ketamine hydrochloride and thiopentone sodium on serum biochemical values have been reported, no literature addressing the effect of anesthesia on lipid parameters in bonnet macaques is available. These findings will be useful in designing experiments assessing pathologic and toxicologic changes in serum lipid parameters and interpreting data obtained from adult bonnet monkeys.

This study compared the efficacy of buprenorphine, carprofen, and a combination of the 2 analgesics in female baboons. Physiologic and behavioral parameters were assessed at baseline and postoperatively for 6 d by use of continuous noninvasive physiologic monitoring and twice-daily videotaping. Prior to surgery, all animals received a pre-emptive dose of either 0.01 mg/kg buprenorphine intramuscularly, 2.2 mg/kg carprofen intramuscularly, or a combination of 0.01 mg/kg buprenorphine and 2.2 mg/kg carprofen intramuscularly. All animals in the carprofen (n = 4) and buprenorphine+carprofen (n = 4) treatment groups appeared to have sufficient analgesia. Three of 4 animals in the buprenorphine group had adequate analgesia. The fourth animal had an elevated heart rate and spent less time standing during the postoperative period. In this study, the use of carprofen or a combination of carprofen plus buprenorphine provided more reliable postoperative analgesia than buprenorphine alone.

Veterinary technology students were asked to participate in a study comparing 2 methods of teaching endotracheal intubation of rabbits. The first group of students was taught to intubate rabbits by the classic 'blind' method. This method entailed holding a sternally recumbent rabbit by its head while the intubator listened to breath sounds through a partially passed endotracheal tube inserted through the rabbit's oral cavity. When the rabbit inhaled, the intubator introduced the endotracheal tube to the lower respiratory tract, timing the movement of the endotracheal tube with the opening of the laryngeal inlet. A second technique, based on the blind method of intubation of horses, was taught to a second set of students. In this method, the operator visualizes the condensation of exhalation from the respiratory tract in the transparent silicon endotracheal tube positioned at the rostral larynx. The operator uses this information to advance the endotracheal tube into the airway. All students were successful with both techniques. Although students intubated the rabbits more quickly with the classic blind technique, they expressed unanimous preference for the lateral recumbency method.

Most gene-targeted mice are produced on a mixed genetic background of C57BL/6 and substrains of 129/Sv. Mating chimeric mice containing 129/Sv-derived embryonic stem cells that are wild type at the agouti locus (A) in a nonagouti (a) donor genetic background with inbred C57BL/6 mice that are homozygous for the nonagouti allele allows the use of coat color to detect germline transmission. Agouti pups from such a cross indicate germline transmission of embryonic stem cell-derived genetic material. However, 129/Sv substrains and C57BL/6 are genetically and phenotypically quite different and, consequently, differing genetic contributions of the 2 backgrounds may influence the phenotype under investigation. To avoid this problem yet maintain the usefulness of the coat color system in detecting germline transmission, we have generated a new strain of mouse by selectively introducing the nonagouti locus into a 129/Sv inbred background. This mouse strain contains 129/Sv-derived genetic material almost entirely except for a small region surrounding the nonagouti allele. Germline transmission can be detected in the usual manner, but the agouti offspring will be almost identical to 129/Sv inbred mice. Thus, the system allows the generation of gene-targeted mutations on a 129/Sv genetic background.

Methods for generating genetically engineered mice have progressed, and the number of valuable mouse strains has increased rapidly, requiring methods for managing and maintaining these strains. Sperm cryopreservation and assisted-reproduction techniques, such as intracytoplasmic sperm injection (ICSI), can contribute greatly; however, the number of possible progeny is limited due to the finite number of cryopreserved preparations. The ability to refreeze and reuse sperm preparations would extend the utility of each cryopreserved sperm preparation. The purpose of this study was to develop a reproduction protocol involving ICSI that yielded live progeny after repeated freezing and thawing of a cryopreserved sperm preparation. We used mouse sperm subjected to repeat freezing and thawing in TYH medium for in vitro fertilization. Three inbred strains of laboratory mice—C57BL/6J, BALB/cA, and C3H/HeN—were reproduced by ICSI after reuse of a sperm preparation that had been frozen and thawed repeatedly. In particular, C57BL/6J progeny could be reproduced from spermatozoa frozen and thawed 10 times. From these results, we conclude that the reuse of cryopreserved spermatozoa can extend the opportunities for reproduction of progeny from cryopreserved sperm and can increase the utility of cryopreserved preparations as bioresources. Our results broaden management options regarding bioresource banking, particularly for mice.

Portable clinical analyzers are currently used in human and veterinary medicine for diagnostic testing and blood monitoring; however, normal values for mice and rats of varying genetic backgrounds have not previously been reported. Blood was collected from unanesthetized mice (n = 131) and rats (n = 76) into lithium heparin tubes for analysis using E6+ cartridges for the portable analyzer. Results of glucose, blood urea nitrogen (BUN), sodium, potassium, chloride, hematocrit, and hemoglobin were compared to published ranges provided by a contract diagnostic laboratory. Analyzer ranges were computed as the mean ± 2 standard deviations of the test samples, such that approximately 95% of tested animals would fall within the resultant range. The degree of overlap between analyzer and published ranges, or the percentage of the published range contained within the analyzer range, was calculated for all analytes. For mice, the ranges of 5 of 7 analytes had more than 57% overlap; for rats, ranges for 6 of 7 analytes had over 65% overlap. After the establishment of normal ranges, the analyzer was used to confirm hyperglycemia in Type I diabetic mice and elevated BUN in rats with induced glomerulosclerosis. The portable analyzer can be a valuable screening tool for both phenotyping and clinical care of rodents, with potential for investigations of both spontaneous and experimental disease in laboratory rodents.

The aim of this study was to evaluate the clinical performance of a portable analyzer for use in cynomolgus monkeys (Macaca fasicularis). During semiannual health screening, blood samples from 23 animals were analyzed by both the portable clinical analyzer and the institutional comparative pathology laboratory. Portable clinical analyzers have been evaluated for use in other species, but the suitability for macaques has not yet been determined. Results for glucose, urea (BUN), sodium, potassium, chloride, hematocrit, hemoglobin, and total CO₂ were compared by overall t test, paired t test, and Pearson correlation. Only glucose and BUN did not differ in the overall t test between methods. Only potassium values did not differ in the paired t test. Compared with those from the portable analyzer, laboratory values were lower for glucose, hematocrit, hemoglobin, and total CO₂ and higher for electrolytes and BUN. All values were within normal ranges for cynomolgus macaques which, in this study, were all apparently healthy, physiologically normal animals. We attributed differences between methods to sample type and handling and the physiologic changes in blood after collection. These results indicate that direct comparison of values obtained through different methods may not be valid, and normal ranges for point-of-care devices should be developed for each species.

Normal hematologic values for African green monkeys have been reported, but these results are confounded by the effect of chemical restraint (for example, ketamine), physical restraint, and capture stress. The dual-lumen central venous catheter, jacket, and tether combination we describe here allows intravenous fluid administration and repeated blood sampling without the use of anesthesia or inducing capture-related stress. The use of a low-concentration heparin solution for catheter maintenance significantly increased the mean patency time, compared with a saline-only catheter flush solution. Adding a low-concentration heparin solution creates a suitable system for serial blood collection in the African green monkey for as long as 25 d.

The purpose of this study was to compare the efficacy of various external heating devices in maintaining body temperature in anesthetized rabbits (Oryctolagus cuniculus). Rabbits were divided into 3 groups and placed on either no heating device, a circulating warm-water blanket, or a forced-air warming device. The animals underwent identical surgical procedures unrelated to the scope of the study, and body temperatures were monitored at 5-min intervals for a 45-min period. Results showed that rabbits had a statistically significant loss of body temperature during the procedure when no heating device was used, no significant loss in body temperature with the use of the forced air-warming device, and a minor increase in body temperature with the use of the circulating warm-water blanket. This study shows that external heating devices are necessary for maintenance of normal body temperature in rabbits under general anesthesia, and forced-air warming devices and circulating warm-water blankets are effective heating devices.

Ovarian hyperstimulation syndrome (OHS) is a rare but sometimes fatal iatrogenic complication of ovarian stimulation associated with the administration of exogenous gonadotropins to women undergoing treatment for infertility. Laboratory Xenopus spp are commonly treated with human chorionic gonadotropin (hCG) to stimulate ovulation and optimize the number of oocytes harvested for use in biomedical research. Here we report cases of OHS in 2 gonadotropin-treated laboratory Xenopus laevis. After receiving hCG, the frogs developed severe subcutaneous accumulation of fluid, coelomic distention, and whole-body edema and were unable to dive, although they continued to eat and swim. At postmortem examination, extensive subcutaneous edema was present; ascites and massive numbers of free-floating eggs were found in the coelomic cavity and in aberrant locations: around the heart-sac and adhered to the liver capsule. Whole-body edema, gross enlargement of the ovaries, ascites, and abdominal distention are findings comparable to those observed in women with OHS. The pathophysiology of OHS is thought to be related to hormonally induced disturbances of vasoactive mediators, one of which may be vascular endothelial growth factor secreted by theca and granulosa cells. We know of no other report describing OHS-like symptoms in gonadotropin-treated frogs, and the cases described here are 2 of the 3 we have observed at our respective institutions over the last 6 y. According to these results, OHS appears to be rare in gonadotropin-treated laboratory Xenopus. However, the condition should be included in the differential diagnosis for the bloated frog.

We describe a case of porcine dermatitis and nephropathy syndrome (PDNS) in a 14-wk-old Yorkshire pig purchased from a commercial farm for research use. Physical examination of the affected animal upon arrival revealed multifocal, red, papular skin lesions on the rump, vulva, perineum, thighs, and lower hindlegs. At necropsy, gross lesions consisted of dermatitis, bilaterally enlarged kidneys and patchy pulmonary congestion. Histologic findings included multiorgan necrotizing vasculitis with prominent lesions in the skin, kidneys, lung, spleen, and liver. Immunohistochemical staining for porcine circovirus type 2 (PCV2) was strongly positive in affected areas of kidney and spleen. In light of the clinical assessment and gross and histologic findings, a diagnosis of PDNS was made. We emphasize the importance of considering PDNS as a differential diagnosis in laboratory swine with skin lesions.