Bartonella henselae in a dog with ear tip vasculitis.

BACKGROUND: Bartonella henselae, a Gram-negative, zoonotic, alpha-proteobacteria has been previously implicated in association with cutaneous vasoproliferative lesions (bacillary angiomatosis), nodular panniculitis and multifocal erythema (erythema multiforme) in dogs. OBJECTIVE: Describe clinical, microbiological and histological lesions in a dog with ear margin vasculitis and B. henselae infection. ANIMALS: A 12-month-old, specific pathogen-free intact female beagle dog maintained in a vector-free laboratory animal resource facility. METHODS AND MATERIALS: Bartonella and Rickettsia serological evaluation, Bartonella and Rickettsia PCR, Bartonella alpha-proteobacteria growth medium (BAPGM) enrichment blood culture/PCR, histopathological investigation and confocal immunohistochemical evaluation. RESULTS: Serological investigation (seroreversion) and PCR testing of aural tissue biopsies failed to support Rickettsia rickettsii as a cause of the aural vasculitis; however, B. henselae, genotype San Antonio 2 DNA was amplified and sequenced from both ear tip margins and from normal-appearing abdominal skin. Seroconversion to B. henselae was documented retrospectively by IFA testing. Bartonella henselae organisms were visualized by confocal immunostaining within all three biopsies. Histopathology revealed small vessel necrotizing vasculitis and dermal necrosis. Bartonella henselae seroreversion and complete resolution of skin lesions occurred in conjunction with administration of oral doxycycline and enrofloxacin for six weeks. CONCLUSIONS AND CLINICAL IMPORTANCE: Bartonella henselae is an emerging zoonotic pathogen that has been associated with leucocytoclastic vasculitis in humans and may have had a contributing or causative role in the development of the cutaneous aural margin vasculitis in this beagle.

Preclinical derivation and imaging of autologously transplanted canine induced pluripotent stem cells.

Derivation of patient-specific induced pluripotent stem cells (iPSCs) opens a new avenue for future applications of regenerative medicine. However, before iPSCs can be used in a clinical setting, it is critical to validate their in vivo fate following autologous transplantation. Thus far, preclinical studies have been limited to small animals and have yet to be conducted in large animals that are physiologically more similar to humans. In this study, we report the first autologous transplantation of iPSCs in a large animal model through the generation of canine iPSCs (ciPSCs) from the canine adipose stromal cells and canine fibroblasts of adult mongrel dogs. We confirmed pluripotency of ciPSCs using the following techniques: (i) immunostaining and quantitative PCR for the presence of pluripotent and germ layer-specific markers in differentiated ciPSCs; (ii) microarray analysis that demonstrates similar gene expression profiles between ciPSCs and canine embryonic stem cells; (iii) teratoma formation assays; and (iv) karyotyping for genomic stability. Fate of ciPSCs autologously transplanted to the canine heart was tracked in vivo using clinical positron emission tomography, computed tomography, and magnetic resonance imaging. To demonstrate clinical potential of ciPSCs to treat models of injury, we generated endothelial cells (ciPSC-ECs) and used these cells to treat immunodeficient murine models of myocardial infarction and hindlimb ischemia.

Analgesic effects of tramadol, tramadol-gabapentin, and buprenorphine in an incisional model of pain in rats (Rattus norvegicus).

Postoperative pain management in laboratory animals relies heavily on a limited number of drug classes, such as opioids and nonsteroidal antiinflammatory drugs. Here we evaluated the effects of saline, tramadol, tramadol with gabapentin, and buprenorphine (n = 6 per group) in a rat model of incisional pain by examining thermal hyperalgesia and weight-bearing daily for 6 d after surgery. All drugs were administered preemptively and continued for 2 consecutive days after surgery. Rats treated with saline or with tramadol only showed thermal hyperalgesia on days 1 through 4 and 1 through 3 after surgery, respectively. In contrast, buprenorphine-treated rats showed no thermal hyperalgesia on days 1 and 2 after surgery, and rats given tramadol with gabapentin showed reduced thermal hyperalgesia on days 2 and 4. For tests of weight-bearing, rats treated with saline or with tramadol only showed significantly less ipsilateral weight-bearing on day 1 after surgery, whereas rats given either buprenorphine or tramadol with gabapentin showed no significant change in ipsilateral weight-bearing after surgery. These data suggest that tramadol alone provides insufficient analgesia in this model of incisional pain; buprenorphine and, to a lesser extent, tramadol with gabapentin provide relief of thermal hyperalgesia and normalize weight-bearing.

The pharmacokinetics of enrofloxacin in adult African clawed frogs (Xenopus laevis).

Pharmacokinetics of enrofloxacin, a fluoroquinolone antibiotic, was determined in adult female Xenopus laevis after single-dose administration (10 mg/kg) by intramuscular or subcutaneous injection. Frogs were evaluated at various time points until 8 h after injection. Plasma was analyzed for antibiotic concentration levels by HPLC. We computed pharmacokinetic parameters by using noncompartmental analysis of the pooled concentrations (naive pooled samples). After intramuscular administration of enrofloxacin, the half-life was 5.32 h, concentration maximum was 10.85 µg/mL, distribution volume was 841.96 mL/kg, and area under the time-concentration curve was 57.59 µg×h/mL; after subcutaneous administration these parameters were 4.08 h, 9.76 µg/mL, 915.85 mL/kg, and 47.42 µg×h/mL, respectively. According to plasma pharmacokinetics, Xenopus seem to metabolize enrofloxacin in a manner similar to mammals: low levels of the enrofloxacin metabolite, ciprofloxacin, were detected in the frogs' habitat water and plasma. At necropsy, there were no gross or histologic signs of toxicity after single-dose administration; toxicity was not evaluated for repeated dosing. The plasma concentrations reached levels considered effective against common aquatic pathogens and suggest that a single, once-daily dose would be a reasonable regimen to consider when treating sick frogs. The treatment of sick frogs should be based on specific microbiologic identification of the pathogen and on antibiotic susceptibility testing.