Persistent Frenulum of the Epiglottis in Four Foals

OBJECTIVE: To report the clinical signs and management of 4 foals with persistent frenulum of the epiglottis. STUDY DESIGN: Case report. ANIMALS: Four newborn foals. METHODS: Foals were admitted with a complaint of oronasal reflux after nursing. Variable systemic signs of aspiration pneumonia were evident. Nasal endoscopy confirmed persistent dorsal displacement of the soft palate. Persistent frenulum of the epiglottis, confirmed by oral endoscopic examination, was transected. RESULTS: After surgery, all foals had the epiglottis positioned normally, dorsal to the soft palate. Clinical signs of oronasal reflux resolved by the second nursing attempt in 3 foals, whereas this was difficult to assess in one foal that was nursed intermittently because of the mares behavior. This foal died 2 days later. The other 3 foals have had normal epiglottic function for 2-4 years. CONCLUSIONS: Persistent frenulum of the epiglottis should be considered in foals with oronasal reflux from birth. With appropriate medical and surgical management the prognosis for resolution should be good.     

Alternate Pathway of Infection with Hepatozoon americanum and the Epidemiologic Importance of Predation

Background: The range of American canine hepatozoonosis (ACH) is expanding from the southern USA northward. Transmission of Hepatozoon americanum occurs by ingestion of infected Gulf Coast ticks, Amblyomma maculatum. The source of the protozoan for the tick remains undetermined; infected dogs are unusual hosts for the tick. Objective: Compare possible sources of infection by field investigations of 2 multiple‐dog outbreaks of ACH. Animals: Twenty‐eight privately owned dogs (Canis familiaris), 1 coyote (Canis latrans), 31 wild‐trapped cotton rats (Sigmodon hispidus), 24 wild‐trapped field mice (Peromyscus leucopus), and 9 wild‐caught rabbits (Sylvilagus spp.) from sites in eastern Oklahoma were monitored for hepatozoonosis. Six laboratory‐raised cotton rats (S. hispidus), 6 Sprague‐Dawley rats (Rattus norvegicus), 6 C57BL/6J‐Lystbg‐J/J mice (Mus musculus), 6 outbred white mice (M. musculus), 6 New Zealand white rabbits (Oryctolagus cuniculus), and 2 dogs were acquired through commercial vendors for experimental transmission trials of H. americanum. Methods: Four of 15 dogs in a rural neighborhood and 5/12 hunting Beagles were confirmed to be infected by blood smear examination, muscle biopsy, and polymerase chain reaction assay of the 18S rRNA gene of Hepatozoon species. Histories and tick host preferences led to field collections of common prey of canids and experimental transmission trials of H. americanum to selected prey (M. musculus, S. hispidus, R. norvegicus, and O. cuniculus). Results: Dogs with ready access to prey (4/15 dogs) or that were fed prey retrieved from hunts (5/12 hunting Beagles) became infected, providing evidence that predation is an important epidemiologic component of ACH infection. Experimental transmission studies identified a quiescent, infectious stage (cystozoite) of the parasite that provides an alternate mode of transmission to canids through predation, demonstrating that cotton rats, mice, and rabbits but not brown rats may act as paratenic hosts of H. americanum. Conclusions and Clinical Importance: Predation of prey harboring infected A. maculatum or containing cystozoites of H. americanum in their tissues provide 2 modes of transmission of ACH to dogs, putting unconfined dogs at increased risk of infection in endemic areas.     

Vaginal Neurofibroma in a Hysterectomized Poodle Dog

A 15‐year‐old, spayed, female poodle dog was presented for evaluation of a mass of tissue prolapsed from the vulva. The dog had been hysterectomized when it was 5 years old. A vaginal mass had been removed approximately 10 months before presentation. Haematological and serum biochemistry analyses demonstrated mild leucocytosis and glycaemia. A vaginal smear was predominantly made up of parabasal cells and intermediate cells with no neoplastic cells. Thoracal and abdominal radiographic findings were unremarkable. The ovaries could not be identified using abdominal ultrasonography. A midline exploratory laparotomy identified both ovaries that were surgically excised. The vaginal mass was also removed following an episiotomy procedure. Histopathological examination of the mass demonstrated that it was a neurofibroma. Both ovaries had cystic changes. Four months after the surgery, the owner reported that the dog was clinically normal. To the authors’ knowledge, this is the first reported case of a vaginal neurofibroma after an incomplete ovariohysterectomy in the dog.     

Evaluation of a commercial enzyme-linked immunosorbent assay for detection of Borrelia burgdorferi exposure in dogs

OBJECTIVE: To evaluate the effectiveness of a commercially available ELISA kit for detecting antibodies against Borrelia burgdorferi in dogs. SAMPLE POPULATION: Banked sera from 440 military working dogs were used for serologic analyses. PROCEDURE: Serum samples were analyzed for antibodies against B burgdorferi by use of a commercially available ELISA and subsequently by western blot analysis as a confirmatory test. RESULTS: Results from the ELISA indicated that 89 (20%) samples were positive for exposure to B burgdorferi or canine Lyme disease vaccine, and 351 (80%) were negative. Follow-up testing by western blot analysis indicated that results for 109 (25%) samples were positive and 331 (75%) were negative for exposure. All samples that had positive results on the ELISA also had positive results on western blot analysis (true positives). Of the 351 samples that had negative results on the ELISA, only 331 had negative results on western blot analysis (true negatives). The remaining 20 samples had positive results on western blot analysis. By use of a standard 2 x 2 table, it was determined that the ELISA had a sensitivity of 82%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 94%. CONCLUSIONS AND CLINICAL RELEVANCE: The commercial ELISA kit evaluated in this study appeared to lack adequate sensitivity for detecting all potential cases of borreliosis in dogs. The ELISA was also unable to discriminate natural exposure from exposure attributable to vaccination, which could complicate interpretation of positive results and treatment of dogs with clinical signs.     

Reversible compartmentalization of de novo purine biosynthetic complexes in living cells

Purines are synthesized de novo in 10 chemical steps that are catalyzed by six enzymes in eukaryotes. Studies in vitro have provided little evidence of anticipated protein-protein interactions that would enable substrate channeling and regulation of the metabolic flux. We applied fluorescence microscopy to HeLa cells and discovered that all six enzymes colocalize to form clusters in the cellular cytoplasm. The association and dissociation of these enzyme clusters can be regulated dynamically, by either changing the purine levels of or adding exogenous agents to the culture media. Collectively, the data provide strong evidence for the formation of a multi-enzyme complex, the "purinosome," to carry out de novo purine biosynthesis in cells.     

Climate Change During the Last Deglaciation in Antarctica

Greenland ice core records provide clear evidence of rapid changes in climate in a variety of climate indicators. In this work, rapid climate change events in the Northern and Southern hemispheres are compared on the basis of an examination of changes in atmospheric circulation developed from two ice cores. High-resolution glaciochemical series, covering the period 10,000 to 16,000 years ago, from a central Greenland ice core and a new site in east Antarctica display similar variability. These findings suggest that rapid climate change events occur more frequently in Antarctica than previously demonstrated.