Naturally Acquired Mouse Kidney Parvovirus Infection Produces a Persistent Interstitial Nephritis in Immunocompetent Laboratory Mice.

Mouse kidney parvovirus (MKPV), also known as murine chapparvovirus (MuCPV), is an emerging, highly infectious agent that has been isolated from laboratory and wild mouse populations. In immunocompromised mice, MKPV produces severe chronic interstitial nephropathy and renal failure within 4 to 5 months of infection. However, the course of disease, severity of histologic lesions, and viral shedding are uncertain for immunocompetent mice. We evaluated MKPV infections in CD-1 and Swiss Webster mice, 2 immunocompetent stocks of mice. MKPV-positive CD-1 mice (n = 30) were identified at approximately 8 weeks of age by fecal PCR (polymerase chain reaction) and were subsequently housed individually for clinical observation and diagnostic sampling. Cage swabs, fecal pellets, urine, and blood were evaluated by PCR at 100 and 128 days following the initial positive test, which identified that 28 of 30 were persistently infected and 24 of these were viremic at 100 days. Histologic lesions associated with MKPV in CD-1 (n = 31) and Swiss mice (n = 11) included lymphoplasmacytic tubulointerstitial nephritis with tubular degeneration. Inclusion bodies were rare; however, intralesional MKPV mRNA was consistently detected via in situ hybridization within tubular epithelial cells of the renal cortex and within collecting duct lumina. In immunocompetent CD-1 mice, MKPV infection resulted in persistent shedding of virus for up to 10 months and a mild tubulointerstitial nephritis, raising concerns that this virus could produce study variations in immunocompetent models. Intranuclear inclusions were not a consistent feature of MKPV infection in immunocompetent mice.

Successful management of rabbit anesthesia through the use of nasotracheal intubation.

Although nasotracheal intubation in the rabbit has been briefly described, scientific assessment of the procedure has not been reported. In this report we describe nasotracheal intubation performed in 38 male New Zealand White rabbits (3.0 to 5.5 kg) used for a vascular patch study. The rabbits were placed under general anesthesia twice, with 2 mo between the initial and final intubations. Rabbits were intubated by the oral or nasotracheal route and compared. Previous literature dismissed nasotracheal intubation, citing the possibility of introducing pathogens into the lungs and the necessity of high oxygen flow rates (presumably greater than 3 L/min). However, no clinical signs of respiratory disease were noted among the study animals, nor were high oxygen flow rates necessary. Several key points collectively facilitated a successful procedure. Total relaxation was essential, modification of the classic blind approach eased placement, a correct approach was necessary, and our development of a unique method of securing the tube improved tube management. The findings suggest that nasotracheal intubation can be used as an easy, less traumatic method of rabbit intubation when compared with orotracheal intubation.

An acute osteomyelitis model in traumatized rat tibiae involving sand as a foreign body, thermal injury, and bimicrobial contamination.

The multfactorial nature of bone injuries in modern warfare and emergency trauma patients warrants enhancement of existing models. To develop a more appropriate model, rat tibiae (n = 195) were mechanically injured, divided into 2 groups (with or without thermal injury), and contaminated with a range of Staphylococcus aureus (Cowan 1) inocula. In some experiments, S. aureus inocula also contained Escherichia coli or foreign bodies (sand or soil). The primary outcome measure was the amount of S. aureus remaining in the tibia (tibial bacterial load) 24 h after contamination, reported as log10 cfu/g bone. S. aureus showed ID50 and ID95 values of 72 and 977 cfu, respectively. Values were lower than seen previously by using S. aureus strain SMH. S. aureus tibial bacterial loads were higher in tibiae with mechanical and thermal injury (log10 4.15 +/- 0.27 cfu/g) versus mechanical injury alone (log10 3.1 +/- 0.47 cfu/g, P = 0.028). The addition of E. coli to the S. aureus inoculum had no effect on tibial bacterial loads (S. aureus only, log10 4.24 +/- 0.92 cfu/g; S. aureus + E. coli, log10 4.1 +/- 1.0 cfu/g, P = 0.74). Sand, added as a foreign body, increased tibial bacterial load. Combined mechanical and thermal trauma of the tibia is associated with increased S. aureus tibial bacterial loads, increasing the risk of acute osteomyelitis. Understanding the interplay of mechanical and thermal injuries, bimicrobial contamination, and foreign bodies may improve our understanding of traumatic bone injuries and the pathogenesis of osteomyelitis.

Comparison of tympanic, transponder, and noncontact infrared laser thermometry with rectal thermometry in strain 13 guinea pigs (Cavia porcellus).

The purpose of this experiment was to assess the practicality, ease, and reliability of using tympanic, transponder, and noncontact infrared laser thermometry versus rectal thermometry in strain 13 guinea pigs. Body temperatures were measured by all four methods within each animal over 10 min, and three sets of measurements were taken over 2 days. Each method was compared for agreement over time and agreement with the rectal temperature of each animal. Over time the transponder temperatures were the most reliable and had the closest agreement with the rectal temperatures. There was an overall difference in mean temperatures among methods but not between times, indicating that the guinea pigs had stable body temperatures over different time periods. Although the mean temperatures from the transponder and tympanic thermometers were not significantly different from the rectal temperatures, only the transponder method was in close agreement with the rectal method. The tympanic and noncontact infrared laser methods had poor agreement with the rectal method. These study results suggest that transponder thermometry is an easy and accurate alternative to rectal thermometry in strain 13 guinea pigs.