Assessing Methods for Replacement of Soiled Bedding Sentinels in Cage-level Exhaust IVC Racks.

Soiled bedding sentinel programs have long been the cornerstone of rodent health monitoring surveillance. Many recent studies have evaluated methods to replace live animals in these programs; however, the type of ventilated rack being used greatly influences the detection rate of adventitious pathogens. This study evaluated 4 alternative sampling techniques across 5 distinct vivaria and assessed their accuracy in detecting 5 pathogens. Testing was done in an operational (real-world) setting using IVC racks that vent air at the cage level. The 5 agents surveyed were mouse norovirus, Helicobacter spp., Rodentibacter spp. Entamoeba muris, and Spironucleus muris. Samples were collected for subsequent PCR assays as follows: 1) cages with live sentinels exposed to soiled bedding; 2) filter paper placed on the lid of an unoccupied cage containing soiled bedding; 3) filter paper placed in the bedding of an unoccupied cage that contained soiled bedding; 4) swabs from an unoccupied sentinel cage that contained soiled bedding; and 5) pooled swabs from colony cages admixed with swabs from soiled bedding sentinel mice. Cumulative accuracy for all pathogens of interest was highest with the existing soiled bedding sentinel program, followed by pooled swabs of colony cages mixed with swabs from occupied soiled bedding sentinel cages. Soiled bedding sentinel cages detected mouse norovirus, Helicobacter spp., and S. muris with the highest accuracy; the pooled swabs were best in detecting Rodentibacter spp. and E. muris. The findings suggest that with the type of rack and caging used in our facilities, the soiled bedding sentinel method has highest concurrence with the expected health status of an animal room, and the results from this method can be enhanced with the addition of pooled swabs of colony animals.

Life-threatening hyperkalemia from cream of tartar ingestion.

INTRODUCTION: Cream of tartar (potassium bitartrate) has a long history as a cooking aid and medicinal purgative. Despite containing large amounts of potassium, there are no well-documented cases of it causing toxicity. We report two cases in which intentional ingestions of cream of tartar resulted in life-threatening hyperkalemia. In addition, we briefly review the use of cream of tartar as a historical purgative. CASE REPORTS: In both cases, individuals ingested a large quantity of cream of tartar in an effort to "clean themselves out". They manifested similar initial symptoms (vomiting), abnormal serum potassium (>8.0 mmol/L), and EKG's with peaked T waves. Both patients were treated for hyperkalemia and recovered without complication. A search for articles on an academic internet database failed to identify any cases specifically dealing with ill effects of potassium bitartrate and numerous websites continue to purport its beneficial health effects. CONCLUSION: Ingestion of cream of tartar can potentially result in life-threatening hyperkalemia.

Health Evaluation of Experimental Laboratory Mice.

Good science and good animal care go hand in hand. A sick or distressed animal does not produce the reliable results that a healthy and unstressed animal produces. This unit describes the essentials of assessing mouse health, colony health surveillance, common conditions, and determination of appropriate endpoints. Understanding the health and well-being of the mice used in research enables the investigator to optimize research results and animal care.

Mammary ductal carcinoma with comedo pattern in a rhesus macaque.

A 23-year-old female rhesus macaque presented with a 2.5-cm diameter, firm, moveable, lobulated subcutaneous mass associated with a supranummary teat on the right side of the chest. This animal was a retired breeder, currently in an aging study. No exogenous hormone treatments were noted in the animal's history. Chest radiographs were within normal limits. Blood screens showed no noteworthy variations from normal. Needle aspirate cytology showed clusters of neoplastic cells. Grossly the mass was well circumscribed, firm, and homogeneously tan, with a glandular appearance. Differential diagnoses included sebaceous or mammary adenoma, carcinoma in situ, and lobular or ductular carcinoma. Histopathology was consistent with a mammary ductal carcinoma with comedo pattern. Subsequent needle aspirate cytology from an adjacent right axillary lymph node showed tumor cells with a few lymphoid cells, interpreted as lymphatic spread. Chest radiographs 2 and 6 weeks postbiopsy showed no evidence of pulmonary metastasis. After 1 year, there was no marked change on chest radiographs, but a small cluster of new nodules was palpable in the right axillary region. Histopathology of an excisional biopsy of the new nodules indicated tumor growth subjacent to regional lymph nodes. Further treatment was not performed and the animal remained clinically normal five years after the initial diagnosis. Spontaneous mammary neoplasia is a major concern in human medicine, yet it rarely has been reported to occur in nonhuman primates. This case is important in documenting an additional case of spontaneous mammary tumor development.

Stroke in the female: role of biological sex and estrogen.

Women are protected from stroke relative to men until the years of menopause. Because stroke is the leading cause of serious, long-term disability in the United States, modeling sex-specific mechanisms and outcomes in animals is vital to research. Important research questions are focused on the effects of hormone replacement therapy, age, reproductive status, and identification of sex-specific risk factors. Available research relevant to stroke in the female has almost exclusively utilized rodent models. Gender-linked stroke outcomes are more detectable in experimental studies than in clinical trials and observational studies. Various estrogens have been extensively studied as neuroprotective agents in women, animals, and a variety of in vitro models of neural injury and degeneration. Most data in animal and cell models are based on 17 beta estradiol and suggest that this steroid is neuroprotective in injury from ischemia/reperfusion. However, current evidence for the clinical benefits of hormone replacement therapy is unclear. Future research in this area will need to expand into stroke models utilizing higher order, gyrencephalic animals such as nonhuman primates if we are to improve extrapolation to the human scenario and to direct and enhance the design of ongoing and future clinical studies and trials.

Low-volume jet injection for intradermal immunization in rabbits.

BACKGROUND: This study tested a low-volume (20-30 microl/20-30 microg DNA) jet injection method for intradermal delivery of a DNA vaccine. Jet injection offers the advantages of a needle-less system, low-cost, rapid preparation of the injected DNA solution, and a simple delivery system. More than one construct can be injected simultaneously and the method may be combined with adjuvants. RESULTS: Low-volume jet injection targeted delivery of a DNA solution exclusively to the dermis and epidermis of rabbits. A three injection series of plasmid DNA, encoding the Hepatitis B Surface Antigen stimulated a humoral immune response in 2/5 rabbits. One rabbit developed a significant rise in antibody titer after 1 injection and one following 2 injections. There were no significant differences between jet injection and particle bombardment in the maximal antibody titers or number of injections before response. A three injection series of the same plasmid DNA by particle bombardment elicited a significant rise in antibody titer in 3/5 rabbits. One rabbit developed antibody after 1 injection and two after 3 injections. In contrast, 0/5 rabbits receiving DNA by needle and syringe injection responded. In the jet injection and particle bombardment groups, gene expression levels in the skin did not predict response. While immune responses were similar, luciferase gene expression levels in the skin following particle bombardment were 10-100 times higher than jet injection. CONCLUSION: Low-volume jet injection is a simple, effective methodology for intradermal DNA immunization.