According to serologic testing, murine norovirus is the most prevalent viral pathogen in contemporary laboratory mice. Previously, murine norovirus 1 (MNV-1) was the only norovirus reported to infect research mice. In this study, 3 novel murine norovirus strains—MNV-2, MNV-3, and MNV-4—were isolated from geographically separate mouse research colonies. All 4 murine norovirus strains used as individual antigens in microsphere fluorescent immunoassays displayed serologic cross-reactivity to serum from mice inoculated with MNV-1, MNV-2, MNV-3, or MNV-4. In addition, reverse transcriptase–polymerase chain reaction analysis at 8 wk postinoculation detected virus in the feces and tissues of all mice experimentally inoculated with MNV-2, MNV-3, or MNV-4. This finding suggests that mice can have prolonged fecal shedding of and can become persistently infected with murine noroviruses.

Human patients with renal disease frequently develop disturbed sleep and severe fatigue. To develop a model for studying factors that contribute to these symptoms, we characterized the sleep patterns of various strains of mice after acute challenge with the fungal organism Candida albicans. After intravenous administration to mice, C. albicans typically colonizes the kidney, producing acute pyelonephritis. Various strains of inbred mice demonstrate marked variation in the temperature and sleep responses that develop after challenge, with individual strains generally showing increased or reduced somnolence in association with fever or hypothermia, respectively. C. albicans-infected mice may be a useful model for identifying the genes and mechanisms that link sleep, temperature, fatigue, and the immune response.

Phenotypic analysis of mutant mice is limited by lack of accurate, simple, and nondestructive in utero imaging techniques. This study evaluated the usefulness of ultrasound imaging (US) to stage fetal mouse gestational age (GA) and depict morphologic development. We imaged 16 pregnant CD-1 mice and a total of 92 fetuses with a 15-MHz US transducer from 9.5 d postcoitus (DPC) until 20.5 DPC or delivery. Parameters recorded included gestational sac dimensions, crown–rump length (CRL), biparietal diameter (BPD), thoracoabdominal diameter (TAD), onset of cardiac activity, and morphologic development. At 9.5 d DPC, all gestations appeared as rounded sacs, with a diameter (mean ± standard error) of 4.4 ± 1 mm. BPD, CRL, and GA were highly correlated. The following structures were first identifiable at the following GA: cardiac activity, 10.5 DPC; major cardiovascular structures, 11.5 DPC; limb buds, 10.5 DPC; spine, 12.5 DPC; face and skull ossification, 13.5 DPC; rib ossification, 15.5 DPC; hind- and forelimb digits, 15.5 DPC; stomach and urinary bladder, 17.5 DPC; visualization of the rhombencephalic vesicle, 13.5 DPC; and visualization of the lateral ventricles, 14.5 DPC. The echogenic lungs were distinct from the liver as early as 12.5 DPC. The circle of Willis was detectable with color Doppler as early as 13.5 DPC and was easily visualized at 15.5 DPC. We found that US provides accurate, simple staging criteria for fetal mouse gestational development after 9.5 DPC and may be a nondestructive means of documenting phenotypic alterations in mutant mice in utero.

Chlamydia pneumoniae is a common human respiratory pathogen, and sera from infected individuals recognize several proteins of C. pneumoniae. We produced C. pneumoniae-specific proteins in a Bacillus subtilis expression system. We then used these recombinant C. pneumoniae proteins and purified C. pneumoniae elementary bodies as antigens in enzyme immunoassays to assess the kinetics and protein specificity of the systemic and mucosal antibody responses induced by C. pneumoniae intranasal infection in BALB/c mice. The systemic antibodies in mice recognized strong 'key' immunogens of Chlamydia, Omp2 and Hsp60, but weakly targeted the MOMP protein, the major immunogen in chlamydial species other than C. pneumoniae. The IgA antibodies in bronchial secretions specifically recognized the putative surface protein of C. pneumoniae, Omp4. Our preliminary observations point to the necessity of further characterization of the mucosal antibody response during C. pneumoniae infection.

In the face of emerging multidrug-resistant microbes, reliable animal models are needed to study potential new therapies in infected wounds. To this end, we implanted screw-top titanium chambers subdermally in full-thickness wounds on both flanks (n = 6 per flank) of 2 Goettinger minipigs. After 1 wk, chambers were inoculated with Staphylococcus aureus, Pseudomonas aeruginosa, or vehicle only. Throughout the study, wound fluid was harvested for quantitative bacterial cultures to monitor infection. Animals were followed for 4 wk, after which tissue biopsies were taken for histologic analysis and quantitative bacterial counts. The implanted titanium chambers were well tolerated by the pigs throughout the study. After inoculation of the chambers, wound infection was established and maintained for 14 d. Despite infection, no systemic effects were noted. Cross-contamination was negligible, compared with the vehicle-only control. After tissue ingrowth, each chamber creates a closed system that allows harvest of exudate or application of substances without loss of material from the chamber. Because 12 chambers are implanted in each pig, researchers have the opportunity to compare multiple treatment options (for example, antibiotics, antimicrobial peptides, gene therapy) in the same animal, with no interindividual variation. We conclude that the use of titanium chambers in pigs provides a reliable and reproducible in vivo model to investigate wound healing, wound infection, and treatment options.

We used various substrates and selective inhibitors of human cytochrome P450 (CYP) isozymes as probes to study the metabolism of liver microsomes from Chinese Bama miniature pigs. Nifedipine oxidation (NOD) and testosterone 6β-hydroxylation (6β-OHT) activities were similar between human liver microsomes and those from Bama miniature pigs. However, compared with those from humans, liver microsomes from Bama miniature pigs showed decreased phenacetin O-deethylation, coumarin 7-hydroxylation, and chlorzoxazone 6-hydroxylation activities, whereas dextromethorphan O-demethylation activity was increased. Ketoconazole selectively inhibited NOD and 6β-OHT activities in microsomes from Bama pigs, and 8-methoxypsoralen and tranylcypromine inhibited coumarin 7-hydroxylation in pig microsomes. However, furafylline and quinidine failed to selectively inhibit phenacetin O-deethylation and dextromethorphan O-demethylation in microsomes from Bama pigs, whereas chlormethiazole more efficiently inhibited coumarin 7-hydroxylation activity than chlorzoxazone 6-hydroxylation in pig microsomes. Our results suggest that liver microsomes from Chinese Bama miniature pigs are similar to those from humans in regard to metabolism of nifedipine and testosterone (both are probe substrates for human CYP3A4). In addition, chemical inhibitors used as specific probes for human P450 enzymes did not always show the same selectivity toward corresponding enzyme activities in liver microsomes from Bama pigs. However, ketoconazole (a potent inhibitor of human CYP3A4) could be used as a selective inhibitor probe for the NOD and 6β-OHT activities in liver microsomes from Chinese Bama miniature pigs.

In contrast to those for human females, observational cycle data available for chimpanzees suggest that menstrual cycling, and thus reproductive potential, continues until near death. This study documents age-related changes in estrous cycling and hormone profiles in 14 female chimpanzees (Pan troglodytes) ranging in age from 31 to 50 y. Estrous data were analyzed from daily cycle charts, averaging 13.3 y of cycle data per subject, after omission of gestational and postpartum amenorrhea. Concentrations of total luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E₂), and other hormones were assayed in serum samples taken biannually. Sample collection times were chosen to avoid the ovulatory LH and FSH peaks of the female's cycle and yielded a mean of 19.6 serum samples over an average of 14.4 y per subject. Analysis of cycle charts revealed a negative relationship between age and the percentage of cycle days at maximal tumescence. There also were positive relationships between age and the length of the estrous cycle and age and the percentage of cycle days at complete detumescence. Analysis of hormonal data revealed curvilinear relationships between age and both LH and FSH. These cycle and hormonal changes mirror those in perimenopausal and menopausal women. Our data provide evidence of perimenopause (at 30 to 35 y) and menopause (at 35 to 40 y) in the chimpanzee.