Current literature suggests that the effects of midazolam, a water-soluble benzodiazepine, on blood pressure in swine are minimal. The hypothesis of the study reported here was that a light sedative dose would induce a decrease in blood pressure in this species. Healthy female Yucatan Micropigs (n = 20), 16 to 30 (mean, 22) kg, aged four six months, were individually placed in a humane restraint sling and allowed to acclimate. Systolic (SBP), diastolic (DBP), and mean (MBP) blood pressures (mmHg) and heart rate (HR; beats per min [bpm]) were measured by use of oscillometry. The pressure cuff was placed at the base of the tail, and five sets of values were recorded at five-min intervals, beginning at 10 and ending 30 min after cuff placement. Following a three- to four-day rest period, this procedure was repeated with the addition of a dose of 0.5 mg of midazolam HCl/kg of body weight given intramuscularly at the time of cuff placement. A paired one-way Student's t-test was used to compare the means of the five measures between control and midazolam treatment. Mean ( SD) differences for SBP, DBP, MBP, and HR were 18.9 (± 3.97), 17.8 (± 5.27), and 18.6 (± 5.09) mmHg and 20.7 (± 3.73) bpm, respectively. All four parameters were significantly reduced in the midazolam-sedated group (P < 0.001). The maximal decrease in SBP, DBP, and MBP occurred at 15 and 20 min after dosing. Mean values based on the means of the five measures were 128 (± 12.6), 80 (± 9.4), and 99 (± 9.2) mmHg and 135 (± 17.4) bpm, and 109 (± 15.4), 63 (± 12.6), and 80 (± 13.6) mmHg and 115 (± 15.5) bpm for SBP, DBP, MBP, and HR in the control (n = 20) and midazolam (n = 20) groups, respectively. The control values can serve as normal oscillometric values for this age, sex, and breed of Micropig. We conclude that midazolam, given intramuscularly at a sedative dosage, negatively affects cardiovascular parameters measured by use of a blood pressure cuff, in sexually mature female Micropigs, compared with values in untreated pigs, which is similar to reports for humans.

Chicken heterophil polymorphonuclear leukocytes (CPMNLs) have NADPH oxidase activity, but lack myeloperoxidase (MPO). Stimulation of CPMNLs by phorbol 12-myristate 13-acetate or chicken opsonified zymosan results in luminoldependent chemiluminescence (CL) activity, which is small relative to that of human peroxidase-positive neutrophils (HPMNLs), as well as lucigenin-dependent CL, comparable to HPMNL responses. Inhibitors were used to investigate and characterize the CL activity of CPMNLs. Inhibition constants were calculated, using Dixon inhibition analysis, or were reported as the concentration producing 50% inhibition of the magnitude of CL responses. Azide and cyanide are effective inhibitors of luminol CL in HPMNLs, although these peroxidase inhibitors do not inhibit either luminol or lucigenin CL of CPMNLs. Since these agents also inhibit eosinophil peroxidase, lack of inhibition of CPMNL CL indicates that the small percentages of peroxidase-positive eosinophils in CPMNL preparations are not responsible for the luminol CL observed. Iodoacetate and fluoride, pre-oxidase and pre-peroxidase inhibitors of glycolytic metabolism, effectively inhibit lucigenin and luminol CL activities in CPMNLs. Superoxide dismutase competitively inhibits lucigenin and luminol CL in CPMNLs, but catalase is an ineffective inhibitor. Although luminol is efficiently dioxygenated by a MPO-dependent mechanism in HPMNL, use of peroxidase-deficient CPMNLs indicates that this substrate does not exclusively measure peroxidase activity.

Background and Purpose: Anomalous (preduodenal) portal vein was found in AKR/J mice. It is a rare congenital malformation in humans, and to the authors' knowledge, has never been reported in laboratory animals. Morphology, clinical signs of disease, and heritability of this anomaly were examined. Methods: Fifty-three strains of inbred mice (6,026 mice) in our mouse colony were examined for preduodenal portal vein and its association with clinical signs of disease (vomiting or abdominal pain) and other anomalies. Heritability also was tested by use of cross-backcross matings of AKR/J mice with clinically normal PT mice. Results: The portal vein was found at the ventral side of the duodenum in most (98%) AKR/J mice, whereas it ran at the dorsal side of the duodenum in 52 other inbred mouse strains in our mouse colony. Clinical signs of disease and other congenital anomalies were not detected in this strain of mice, although position has a high association with other congenital anomalies in humans. Heritability testing of this anomaly in AKR/J mice indicated single autosomal recessive inheritance. Conclusions: Preduodenal portal vein found in AKR/J mice is a single autosomal recessive mutation, but is not associated with clinical signs of disease and other congenital malformations.

Background and Purpose: Pentobarbital and ketamine-xylazine anesthesia in mice result in markedly decreased left ventricular fractional shortening and cardiac output. However, to the authors' knowledge, the effect of shortacting, alcohol-based anesthesia on these parameters is unknown. Methods: Fifteen mice (FVB/N, C57Bl/6J, A/J, n = 5 each) underwent high-resolution (15 MHz) 2-dimensional-directed M-mode echocardiography before and after undergoing 2.5% tribromoethanol anesthesia (0.01 ml/g of body weight). Results: Tribromoethanol anesthesia resulted in significant heart rate slowing (29%) and left ventricular enlargement (20%), and a more modest (12%) reduction in left ventricular fractional shortening. Cardiac output was unchanged. The differences in left ventricular function between conscious and tribromoethanol studies were similar for each of the three strains of mice. Conclusions: Tribromoethanol anesthesia induced only modest effects on M-mode estimates of basal cardiac function and did not influence cardiac output. The effects to tribromoethanol anesthesia were similar among three commonly used mice strains.

Normal reference range intervals for hematologic and serum biochemical values in the chimpanzee (Pan troglodytes) have seldom been reported. The few studies that have been conducted either report values on the basis of a small number of animals, report values for all age groups or both sexes combined, or were designed specifically to document the effect of a particular condition on the normal range of hematologic and serum biochemical values. On the basis of data collected from 133 chimpanzees over a 17-year period, empirically based clinical reference ranges were derived to provide a guide for basic diagnostic and clinical care of chimpanzees. For either sex within each of four age groups, there is a table that summarizes serum biochemical and a table that summarizes hematologic values. These values are compared with prior values, and their importance in the care and well being of captive chimpanzee populations is discussed.

Infant rats are susceptible to persistent rat virus (RV) infection, but risk of persistent infection after prenatal exposure to virus is unclear. We examined this aspect of RV infection in the progeny of dams inoculated with virus during or prior to pregnancy. Sprague-Dawley (SD) dams were infected during pregnancy (gestation day 9) by oronasal inoculation with 10⁵ TCID₅₀ of the UMass strain of RV. SD rats were infected prior to pregnancy by oronasal inoculation of twoday-old females with 10² TCID₅₀ of RV-UMass, which induced persistent infection. They were mated to non-immune males after reaching sexual maturity. Rats were assessed for RV infection by virus isolation, in situ hybridization, contact transmission, or serologic testing. The progeny of dams inoculated with virus during gestation had high prevalence of infection through postpartum week 9 (9 of 12 rats were virus positive at week 3, and 7 of 10 were virus positive at week 9). Additionally, 2 of 10 rats were virus positive at least through postpartum week 15. The progeny from persistently infected, seropositive dams had no evidence of infection and did not transmit infection to contact sentinels. However, 12 dams were virus positive at necropsy and 9 had transmitted infection to their breeding partners. These results indicate that prenatal infection in non-immune dams can lead to RV persistence in their progeny. By contrast, the progeny of persistently infected dams are protected from infection, presumably by maternal antibody, although their dams can transmit infection to their breeding partners.

The analgesic effect of orally administered buprenorphine was compared with that induced by a standard therapeutic injected dose (0.05 mg/kg of body weight, s.c.) in male Long-Evans rats. Analgesia was assessed by measuring pain threshold, using the hot-water tail-flick assay before and after administration of buprenorphine. The results suggest that a commonly used formula for oral buprenorphine in flavored gelatin, at a dose of 0.5 mg/kg, does not increase pain threshold in rats. Instead, oral buprenorphine doses of 5 and 10 mg/kg were necessary to induce significant increases in pain threshold. However, these doses had to be administered by orogastric infusion because the rats would not voluntarily eat flavored gelatin containing this much buprenorphine. The depth of analgesia induced by these infused doses was comparable to that induced by the clinically effective s.c. treatment (0.05 mg/kg).

The Charles River (CR) “hairless” rat is one of the autosomal recessive hypotrichotic animal models actively studied in pharmacologic and dermatologic research. Despite its widespread use, the molecular basis of this monogenic mutation remains unknown, and the skin histologic features of this phenotype have never been described. However, the designation “hairless” has been used as an extension of the hairless mouse (hr) nomenclature on the basis of the clinical absence of hairs in both phenotypes. We present a description of the histopathologic changes in heterozygous and homozygous CR hairless rat mutants during the first month of life. The postnatal homozygous rat skin was characterized by abnormal keratinization of the hair shaft and formation of a thick and dense layer of corneocytes in the lower portion of the epidermal stratum corneum. This layer prevented the improperly keratinized hair shaft from penetrating the skin surface. Starting from the latest stages of hair follicle (HF) development, obvious signs of HF degeneration were observed in homozygous skin. This process was extremely rapid, and by day 12, mainly atrophic HFs with abnormal or broken hairs were present in the skin. Therefore, the mutation in the CR rat abrogates cell proliferation in the hair matrix and affects keratinocyte differentiation in the HF and interfollicular epidermis, a phenotype that is completely distinct from hr/hr. To test whether the CR rat harbored a mutation in the hr gene, we analyzed the coding region of this gene and consensus intron splice site sequences in mutant rats and found no mutation, further supporting phenotypic evidence that the hairless phenotype in CR rats is not allelic with hairless. Finally, using intragenic polymorphisms, we were able to exclude homozygosity at the hairless locus by use of genotypic analysis. Thus, morphologic analysis of successive stages of phenotype development in the CR hairless rat, together with definitive molecular studies, indicate that this mutation may be unique among the other hypotrichotic rat mutations.

Renal development in mammalian kidneys can only be studied in embryonic animals. Hence, research in this area is hampered by the need to maintain pregnant animals and by the small size of the embryonic kidney. Here, we describe a goldfish (Carassius auratus) model for studying renal repair and nephron development in an adult animal. Previous studies have indicated that chemically induced nephrotoxicosis in goldfish is followed by new nephron development. We tested the hypothesis that new nephron development is not a one-time only event and, thus, will occur after repeated nephrotoxic events. We used repeated injections of gentamicin (50 mg/kg of body weight), a nephrotoxic antibiotic, which has been used as a model nephrotoxicant to study renal repair. Fish were allowed either a recovery period of 9 or 24 weeks between injections. In both experiments, new nephrons developed after each injection of gentamicin, supporting our hypothesis. Nephron development occurring after a 9-week recovery period was similar to development observed after a 24-week recovery period; therefore, the shorter experimental paradigm appears sufficient and can save time and money. Future research using this fish nephrogenesis model may identify the genes responsible for nephron neogenesis. Such information is a prerequisite for developing alternative renal replacement therapies based on the induction of de novo nephrogenesis in diseased kidneys.

Hematologic and blood biochemical variables are of great importance in medical and veterinary practice. In addition, these analytes may have significance as potential biomarkers of aging. Previous reports on normative values of these variables in the chimpanzees are based on cross-sectional studies that did not include individuals of advanced age. To address this omission, we performed cross-sectional and longitudinal analyses of hematologic and blood biochemical data collected from chimpanzees over a 9-year period. One-hundred forty-six females and 106 males of ages representing the entire life span of the species were studied. We derived normative cross-sectional values of 14 commonly measured hematologic and 20 blood biochemical variables, which should provide a useful reference for clinical blood studies in chimpanzees. In addition, we found in a cross-sectional regression analysis of our data that most analytes varied significantly between males and females, and that they varied markedly with age. Most variables had year-to-year consistency within the same individuals, as indicated by statistically significant intra-year correlation coefficients. Finally, we performed a longitudinal analysis of the analytes in chimpanzees by calculating the slopes and intercepts of the best-fitting trend line for each individual. The resulting slopes were analyzed by sex and by decade of age of subjects to determine whether trends were consistent. Consistent trends detected in the longitudinal analysis were usually restricted to the first decade of life, and thus represented maturational processes. The overall lack of within-animal trends covering all or most of the period from early adulthood through old age in this 9-year study suggests that a longer period of follow-up than used here may be required to document senescence-related changes.

Background and Purpose: In research facilities using non-human primates, crown-height reduction with partial coronal pulpectomy (“vital pulpotomy”) is routinely performed on canine teeth of adult male monkeys to reduce self-trauma and the potential for injury to staff or cage-mates. Success of pulpotomy techniques in humans is reportedly 40 to 60%. Failure leads to chronic inflammation and pulp necrosis, which introduces variability in research animals, and may affect research results. The purpose of the study reported here was to determine failure rate of this procedure by evaluating clinical and radiographic findings at 3, 9, and 24 months after crown amputation and partial coronal pulpectomy of maxillary canines in adult male rhesus monkeys. Methods: Forty-seven maxillary canine teeth from 24 adult male rhesus monkeys were treated by use of crown amputation and partial coronal pulpectomy, using standard dental technique. Follow-up clinical and radiographic examination was performed 3, 9, and 24 months after surgery. Results: At three months after surgery, there was no clinical evidence of failure at any of the teeth. On the basis of radiographic findings, 2 of 47 teeth had failed and one was suspicious for early failure. At nine months, clinical evidence of failure was not apparent; radiographically, 5 of 44 teeth appeared to have failed and 3 others were suspect. Two years after surgery, failure of 41 teeth was clinically evident in two animals, with radiographic evidence of failure in five, and suspicion of early failure in an additional six. Conclusions: The failure rate of crown amputation and partial coronal pulpectomy of canine teeth in adult male rhesus monkeys is high, and the chronic inflammation associated with this is cause for concern.

Purpose: We investigated the therapeutic potential of the pig-derived antimicrobial peptide protegrin-1 (PG-1) against porcine skin wounds infected with Pseudomonas aeruginosa. Materials and Methods: Using a porcine skin wound model, PG-1 was added to the wound fluid either at the time of P. aeruginosa inoculation, four hours after inoculation or 24 hours after inoculation. Wound fluids were analyzed 20-24 hours later by use of colony-forming unit (CFU) assays, semiquantitative immunoblot analysis for PG-1, and radial diffusion assays (RDA) for residual in vitro activity. Results: Results of the CFU assays indicated a 10,000-fold decrease in the number of bacteria when PG-1 was added at the time of inoculation, a 120-fold decrease when added 4 hours after inoculation and a 10-fold decrease when added 24 hours after inoculation. Results of immunoblot analysis and RDA indicated that PG-1 concentrations for each of the three conditions remained increased in wound fluid 20 to 24 hours after treatment, and correlated with increased residual in vitro antimicrobial activity. Conclusions: These results document that the endogenous antibiotic PG-1 significantly prevented the colonization of P. aeruginosa in wounds and reduced the in vivo bacterial concentration in established wound infections. Therapeutics used in the same animal species from which they were derived are a promising means for preventing and treating localized infections.

Purpose: Bacterial infections of the air sac have been reported in many nonhuman primates. Approaches to the management of airsacculitis have included combinations of medical and surgical therapies. These strategies have often required repeated attempts to drain exudate from the affected air sac, as well as necessitating that the animal endure isolation or undergo intensive postoperative care before returning to its social group. Methods: A stoma was created via deliberate apposition of the air sac lining and skin to allow continuous drainage. Antibiotic therapy based on culture and antimicrobial susceptibility of the air sac contents was administered while the chimpanzee remained in its social group. Results: We were able to attain complete resolution of the infection after a course of oral antibiotic therapy. The stoma closed gradually over a three-week period, and the chimpanzee has remained free of infection since that time. Conclusion: Despite the severity of the air sac infection in this chimpanzee, we were able to resolve the infection easily, using a simple surgical technique. This method allowed treatment without interfering with social standing or subjection to repeated anesthetic and treatment episodes. This method could be a simple, useful alternative for managing airsacculitis in nonhuman primates.

Purpose: To study etiologic aspects of hip dysplasia in a colony of Dutch-belted rabbits. Methods: Rabbits used in the study were part of a reproductive toxicologic study. Incidence of hip dysplasia among 296 Dutch-Belted rabbit kits raised on waxed cardboard, smooth Plexiglas, or Plexiglas covered with textured adhesive strips was recorded. All animals were examined at 2 to 4 weeks of age for inability to adduct one or more limbs, then were classified as normal or dysplastic. A subset of 16 juvenile male rabbits (4 normal, 12 affected) raised on Plexiglas flooring were given a physical examination at 12 weeks of age followed by complete necropsy. In four animals (one normal, three affected), pelvic radiography and neurologic examination were performed. Results: Seven percent of the rabbits kits reared on waxed cardboard flooring and 22% of those reared on smooth Plexiglas flooring developed hip dysplasia. Animals reared on Plexiglas floor with traction strips did not have evidence of hip dysplasia. Among the animals selected for detailed analysis, body weight was similar between rabbits with or without splay leg. Affected animals had splaying of one or both hind limbs, various degrees of flattening and reduction of the size of the femoral head, subluxation of the hip, valgus deformity, and patellar luxation. Histologically, there was marked thickening of the hip joint capsule with fibrocartilage formation, mild trabecular bone loss, and bony sclerosis of the proximal portion of the femur and adductor muscle hypoplasia. Conclusions: Provision of non-slippery flooring during the postnatal period is critical in preventing development of hip dysplasia in rabbits. Hip dysplasia resulted in significant musculoskeletal changes, but not abnormal neurologic development.