Several studies have indicated a strong association between asthma and aspiration of stomach contents. However, the complex association between these inflammatory processes has not been studied extensively in animal models. In the present study, we developed an animal model to evaluate the inflammatory cell, chemokine, and airway responses to asthma complicated by aspiration. The model was produced by sensitizing mice to cockroach allergens from house-dust extracts. Mice with asthma-like airway responses then were inoculated intratracheally with either an acidic solution or saline. Acid aspiration increased airway hyperresponsiveness in mice with asthma for at least 8 h. After 6 h, the combined injury caused an additive, not synergistic, increase in airway hyperresponsiveness and neutrophil recruitment to the airways. Although cysteinyl leukotrienes in bronchoalveolar lavage fluid were higher after acid aspiration, treatment with a receptor antagonist before aspiration did not diminish airway hyperresponsiveness. Vagal mechanisms reportedly mediate airway responses in acid aspiration; however, pretreatment with an anticholinergic agent did not reduce airway responses to acid. These results are consistent with an effective model of the acute effects of aspiration on the allergic lung. Further studies could examine how various forms of aspiration influence the severity of asthma.

Mitogenic growth factors play an important role in cellular development and differentiation. The purpose of this study was to assess the extent to which epidermal growth factor (EGF) and transforming growth factor α (TGFα) and their cognate receptor (EGFR) are crucial for normal preimplantation embryo development. We used RNA interference to decrease expression of growth factors in preimplantation mouse embryos. We microinjected 1-cell mouse embryos individually with short interfering RNA (siRNA) specific to EGF, TGFα, and EGFR and then analyzed temporal and spatial gene expression patterns at different stages of development before implantation. Transfection with siRNA significantly reduced growth factor expression in 1-cell, 2-cell, morula, early-blastocyst, and late-blastocyst embryos to levels similar to those in untreated 'cloned' embryos derived through intracytoplasmic nuclear injection. In addition, siRNA effectively decreased expression of maternally inherited genes between 24 and 72 h after transfection, with recovery of gene expression during late-blastocyst stage at 96 h after transfection. Furthermore, siRNA significantly decreased blastocyst formation, increased the number of apoptotic cells, and reduced the total number of differentiated cells in blastocysts; these changes were greatest after decreasing EGFR and of both EGF and TGFα simultaneously. These results support our hypothesis that EGF and TGFα are crucial for embryo survival and development. Further, dysregulated expression of growth factors is associated with poor development of cloned mouse embryos.

The objective of this study was to determine whether a simple, noninvasive method involving administration of isoproterenol could be used to produce myocardial injury and cardiac dysfunction in the mouse heart with a low incidence of mortality. Adult Swiss–Webster mice were injected with isoproterenol (100 mg/kg SC) once daily for 5 d. Myocardial histology and left ventricular (LV) function were assessed 10 to 14 d after the last isoproterenol injection in 14 surviving isoproterenol-treated mice and 15 saline-treated control mice. Left ventricular systolic and diastolic pressures were evaluated in vitro by means of isovolumically contracting, perfused Langendorff preparations. Isoproterenol induced marked endocardial injury, associated with hypertrophy of surviving myocytes, and an increase in myocardial fibrosis (collagen types I and III according to picrosirius red microscopy). The hearts from isoproterenol-treated mice demonstrated decreased LV compliance, as evidenced by an upward shift in the diastolic pressure–volume relationship, with normal LV systolic function. Isoproterenol administration provides a simple, noninvasive means to induce endocardial injury and diastolic dysfunction without significant impairment of systolic function. This model has a low incidence of mortality and may be useful to assess the effects of gene or stem cell therapy on cardiac dysfunction without the potential confounding effects of invasive procedures.

Spontaneous dwarf rats are a useful experimental model for studying various biologic events associated with pituitary dwarfism. Dwarf rats occurred serendipitously in our colony of Wistar rats during experimental breeding. This study aimed to describe the sleep pattern and physiologic characteristics of these rats compared with normal-sized adult rats. Because growth hormone can attenuate the upregulation of ceruloplasmin expression caused by acute inflammation, we also assessed the basal levels of serum ceruloplasmin in these animals. At 90 d of age, body weight and length were significantly lower in dwarf rats relative to normal rats. Dwarves had lower concentrations of serum testosterone and growth hormone, but progesterone was unchanged. Corticosterone levels did not differ between groups. During the light period, the percentage of sleep time recorded and duration of slow-wave sleep did not differ between groups. However, compared with controls, dwarf rats had marked fragmentation of sleep and less paradoxical sleep. During the dark phase, sleep patterns in dwarf rats were within the normal range. Immunoblotting data showed that the levels of ceruloplasmin in serum were lower in dwarf rats. Our findings provide insight into pathologic processes related to growth hormone deficiency.

Angiogenic factors such as vascular endothelial growth factor (VEGF) are implicated in pulmonary hypertension (PH). However, the pathway of angiogenic factor-mediated pathologic angiogenesis in PH remains unclear. In this study, we evaluated the temporal expression of angiopoietin (Ang) 1, Ang2, and their receptor (Tie2) as well as VEGF, endothelial nitric oxide synthase (eNOS), inducible NOS (iNOS), and heme oxygenase 1 (HO1) in the monocrotaline-induced PH model. Histologic evaluation showed pathologic vascular remodeling in the arteries of lung sections 1 wk after monocrotaline treatment. Protein levels of Ang1, Ang2, eNOS, iNOS, HO1, and VEGF were increased 1 wk after monocrotaline treatment but Tie2 protein levels were decreased 2 wk afterward. These results suggest that Ang2 mediates vascular remodeling in PH by decreasing Tie2 expression. Therefore, the Ang–Tie2 system may play a role in the pathophysiology of PH.

A high incidence of gingival overgrowth occurred in a group of New Zealand White rabbits receiving daily cyclosporine (15 mg/kg IM) while on a retinoblastoma study. Over the course of 2 mo, rabbits presented with clinical signs of ptyalism (4 of 18 rabbits), inappetence (3 of 18), or both (3 of 18); facial dermatitis and erythema occurred secondary to ptyalism. Reducing the dose of cyclosporine to 10 mg/kg led to complete resolution of clinical signs in all but 2 rabbits, which then received azithromycin (62.5 mg PO once daily for 7 d), a common treatment for cyclosporine-induced gingival overgrowth in other species. After dose reduction and azithromycin treatment, clinical signs resolved and did not reoccur for the remainder of the study. Fourteen rabbits were necropsied at the end of the study, and gingival width was measured. Although some rabbits were clinically normal, the gingiva in all rabbits was grossly thickened. Rabbits on cyclosporine had molar gingiva that was significantly thicker (4.8 mm) than controls (2.5 mm) not treated with cyclosporine. Histologic analysis of the gingiva revealed mild to moderate gingival epithelial hyperplasia, hyperkeratosis, and mild inflammation. Gingival overgrowth is a known side effect of cyclosporine administration in other species but, to our knowledge, this report is the first description of the condition in rabbits. Because rabbits frequently are used in studies that involve systemic cyclosporine administration, clinicians are advised to include this possibility in their differential list for cases involving hypersalivation, facial dermatitis, or inappetence in rabbits.

Campylobacter jejuni is 1 of the most common enteric bacterial pathogens worldwide. The mechanisms of pathogenesis remain obscure, in part because of limitations of small animal models. Young ferrets develop diarrhea when fed C. jejuni, but their pathology and the immune response after infection have not been examined in detail. In the present study, we examined the pathogenesis of C. jejuni CG8421 and associated immune responses in ferrets. After oral infection with C. jejuni CG8421, 86.7% of the animals developed diarrhea and inflammatory responses that were similar to those seen in human infection. Pronounced histopathologic changes in the colonic mucosa of infected animals were observed during the acute phase (days 1 through 3) of infection. Electron micrographs of colonic epithelium revealed disruption of the villi and internalized bacteria that were not within membrane vacuoles. During the acute phase, C. jejuni was isolated from the livers of 7 of 9 (78%) animals, and bacteria were visualized immunohistochemically in the livers from 5 of the 7 animals (71%) from which C. jejuni was isolated. A vigorous systemic and mucosal immune response to Campylobacter antigens was elicited after infection of ferrets. The data presented contribute to the current knowledge of the pathogenicity of and immunologic response to C. jejuni CG8421 in ferrets and better understanding of this model.

The characterization of porcine antithrombin III (ATIII)—a highly powerful anticoagulant—is essential for using porcine liver in xenotransplantation applications. The objective of this study was to clarify the functions of porcine ATIII through comparison with human ATIII. We cloned porcine ATIII and compared its important functional sites with those of human ATIII. The full-length cDNA of porcine ATIII was cloned by screening a porcine liver cDNA library, and the ATIII activities of 23 pigs were determined. The full-length cDNA of porcine ATIII spanned 1498 bp and encoded 463 amino acids. Porcine ATIII shared 87.67% nucleotide identity and 89.06% amino acid identity with human ATIII. Complete identity was found at active center Arg393–Ser394, and remarkably high similarities were found at 2 critical heparin-binding sites (residues 41 through 49 and 114 through 156) and in some key residues involved in heparin binding. An ATIII assay found no significant difference between porcine and human plasma. The high level of similarity between porcine ATIII and human ATIII suggests that porcine ATIII will function in a manner similar to human ATIII in xenotransplantation.

Issues of cost and genetics can result in inbreeding of canine genetic disease colonies. Beagles often are used to maintain such colonies, providing stock for outcrosses. Factor VII (FVII) deficiency is a hemostatic disorder found at increased frequency in beagles and has been characterized at the DNA level. Deficiency of FVII presents obstacles in colonies founded with beagles. An initial finding of a FVII-deficient pup from a longstanding colony prompted us to evaluate FVII deficiency fully in this colony. Current and archival records and tissues were used to reconstruct the colony pedigree, assess the contribution from beagles, and test samples to document the source and frequency of the mutant FVII allele. As part of this study we developed a PCR-based diagnostic assay that was simpler than what was previously available. Pedigree analysis revealed a founder effect implicating beagles that led to high frequency (55%) of the mutant allele. In addition, affected animals were identified. The complete picture of the clinical effect within the colony remains unclear, but unusual neonatal presentations, including hemoabdomen, have occurred in pups affected with FVII deficiency. Use of a PCR-based diagnostic assay to screen all potential beagle breeding stock will prevent similar occurrences of FVII deficiency in future canine research colonies.

We performed a cross-sectional study to estimate the prevalence of 2 gamma-2-herpesviruses, rhesus rhadinovirus (RRV) and retroperitoneal fibromatosis herpesvirus (RFHV), in breeding colonies of rhesus macaques. Of 90 animals selected for sampling, 73 (81%) were positive for RRV, which was detected only in blood in 22 (24%), only in saliva in 15 (16%), and in both blood and saliva in 36 (40%). Detection of RRV DNA in blood and saliva was significantly higher in animals younger than 2 y. In comparison, RFHV was detected in 40 (44%) of the 90 animals: only in blood in 5 (6%), only in saliva in 26 (29%), and in both blood and saliva in 9 (10%). Dual infection was detected in 38 (42%) animals; RFHV was only detected in coinfections. The mean RRV genome copy number in blood was significantly higher than that for RFHV. Age was a significant predictor of RRV copy number in blood and RFHV copy number in saliva. Of the 90 animals, 88 (98%) were positive for rhadinoviral antibodies on an immunofluorescent assay. Both RRV and RFHV are highly endemic in socially housed breeding colonies of rhesus macaques, and their patterns of infection are similar to that for the betaherpesvirus rhesus cytomegalovirus.