Anaerobic metabolism of indoleacetate.

The anaerobic metabolism of indoleacetate (indole-3-acetic acid [IAA]) in the denitrifying betaproteobacterium Azoarcus evansii was studied. The strain oxidized IAA completely and grew with a generation time of 10 h. Enzyme activities that transformed IAA were present in the soluble cell fraction of IAA-grown cells but were 10-fold downregulated in cells grown on 2-aminobenzoate or benzoate. The transformation of IAA did not require molecular oxygen but required electron acceptors like NAD(+) or artificial dyes. The first products identified were the enol and keto forms of 2-oxo-IAA. Later, polar products were observed, which could not yet be identified. The first steps likely consist of the anaerobic hydroxylation of the N-heterocyclic pyrrole ring to the enol form of 2-oxo-IAA, which is catalyzed by a molybdenum cofactor-containing dehydrogenase. This step is probably followed by the hydrolytic ring opening of the keto form, which is catalyzed by a hydantoinase-like enzyme. A comparison of the proteome of IAA- and benzoate-grown cells identified IAA-induced proteins. Owing to the high similarity of A. evansii with strain EbN1, whose genome is known, we identified a cluster of 14 genes that code for IAA-induced proteins involved in the early steps of IAA metabolism. These genes include a molybdenum cofactor-dependent dehydrogenase of the xanthine oxidase/aldehyde dehydrogenase family, a hydantoinase, a coenzyme A (CoA) ligase, a CoA transferase, a coenzyme B(12)-dependent mutase, an acyl-CoA dehydrogenase, a fusion protein of an enoyl-CoA hydratase and a 3-hydroxyacyl-CoA dehydrogenase, a beta-ketothiolase, and a periplasmic substrate binding protein for ABC transport as well as a transcriptional regulator of the GntR family. Five predicted enzymes form or act on CoA thioesters, indicating that soon after the initial oxidation of IAA and possibly ring opening, CoA thioesters are formed, and the carbon skeleton is rearranged, followed by a CoA-dependent thiolytic release of another CoA thioester. We propose a scheme of an anaerobic IAA metabolic pathway that ultimately leads to 2-aminobenzoyl-CoA or benzoyl-CoA.

Right ventricular rupture after lateral thoracotomy for removal of rib-associated telangiectatic osteosarcoma in a dog.

OBJECTIVE: To describe a case of a focal right ventricular rupture following removal of a rib-associated telangiectatic osteosarcoma (TOS) in a dog. CASE SUMMARY: A 2-year-old spayed female mixed-breed dog, weighing 20 kg, was presented in compensated hypovolemic shock due to active bleeding into the thoracic cavity. The dog was stabilized with appropriate fluid administration. Subsequent computed tomographic examination revealed a large mineralized mass originating from the body of a rib and displacing the heart. Two days after surgical removal of this mass, focal right ventricular rupture occurred and the dog died. The mass was later identified as a TOS. NEW OR UNIQUE INFORMATION PROVIDED: Although hemothorax secondary to TOS has been described previously, this report describes for the first time, spontaneous focal right ventricular rupture as a rare complication of thoracotomy and rib resection for the removal of a rib-associated, intrathoracic TOS.

Magnetic resonance imaging of feline hippocampal necrosis.

The clinical, neuropathologic, and magnetic resonance (MR) imaging features in four cats with necrosis of the hippocampus and piriform lobe are described. All cats had acute generalized seizures and behavioral changes including aggression, salivation, polyphagia, and disorientation. Routine hematologic, serum chemistry, and cerebrospinal fluid analyses were normal. MR imaging abnormalities were restricted to the area of the hippocampus and piriform lobe. The lesions were T2-hyperintense, T1-hypointense, and were characterized by various degrees of contrast enhancement. Lesions were consistent with necrotizing encephalitis. Two cats were euthanized and underwent postmortem examination within a week after MR imaging due to the lack of response to antiepileptic drug therapy and progressive encephalopathy [corrected] The remaining two cats lived for about four months and were then euthanized because of persistent behavioral and neurologic signs; only one of these cats underwent postmortem examination with histopathologic examination. Histopathological findings were typical of severe, diffuse, bilateral symmetric necrosis, and degeneration of neurons in the hippocampus and piriform lobe, but an etiologic agent was not apparent. This apparently unique feline syndrome, now reported in Switzerland and Italy, has no known cause at this time.

A follow-up study of neurologic and radiographic findings in working German Shepherd Dogs with and without degenerative lumbosacral stenosis.

OBJECTIVE: To identify radiographic abnormalities associated with degenerative lumbosacral stenosis (DLSS) in German Shepherd Dogs (GSDs) and determine whether specific radiographic abnormalities could be used to identify dogs at risk of developing DLSS. DESIGN: Cohort study. ANIMALS: 33 GSDs working as police dogs. PROCEDURES: Results of physical, neurologic, and orthopedic examinations were used to identify dogs with DLSS. Survey radiography of the lumbosacral junction was performed, and radiographs were compared with radiographs obtained 3 years earlier. RESULTS: DLSS was diagnosed in 15 of the 33 (45%) dogs. Thirteen of the 15 dogs with DLSS and 14 of the 18 dogs without DLSS had radiographic abnormalities of the lumbosacral junction. Twenty-two (67%) dogs were able to perform unrestricted duties, including 3 dogs with suspected DLSS. Six (18%) dogs had been excluded from active duty during the period of surveillance because of DLSS. Significant progression in specific clinical and radiographic signs was detected, but multiple logistic regression analysis did not identify any radiographic signs that could be used to predict the development of DLSS. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that survey radiography cannot be used to predict development of DLSS in working GSDs.

Computed tomography in small animals--basic principles and state of the art applications.

Since its clinical introduction, computed tomography (CT) has revolutionized veterinary medicine and is considered to be one of the most valuable tools for the imaging work-up of neurological, oncological and orthopaedic canine and feline patients. In small animals with acute trauma, particularly those involving complex anatomic areas such as the head, spine or pelvis, CT has been established as a standard imaging method. With the increasing availability of radiation therapy in veterinary medicine, CT has also become the principal tool to stage a tumour, assess response, and guide radiation therapy. The increasing availability of helical CT in veterinary medicine has allowed novel techniques such as spiral CT angiography and high-resolution CT. This review provides a brief overview of the historical and technical development of CT and literature reviews of the major clinical CT applications in small animals such as intracranial and extracranial lesions, the spine, the appendicular skeleton, and abdominal and thoracic diseases.

Radiographic, ultrasonographic, and computed tomographic appearance of alveolar echinococcosis in dogs.

Alveolar echinococcosis is a rare metacestodal infection of humans and domestic animals with Echinococcus multilocularis and predominantly affects the liver. In humans, diagnosis is based on serology, ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI), techniques that have not yet been validated for the diagnosis of alveolar echinococcosis in dogs. Therefore, the purpose of this retrospective study was to describe the radiographic, ultrasonographic, and CT appearance of canine alveolar echinococcosis. Eleven dogs with confirmed alveolar echinococcosis (PCR or histology from biopsy material of metacestode tissue) diagnosed between 1995 and 2003 were included in the study. The age of the dogs at initial presentation ranged from 7 months to 10.5 years. Abdominal radiographs were made in nine animals, abdominal ultrasonography was performed in 10 dogs, and two CT studies in one dog, respectively. The history, clinical presentation, and laboratory findings for the 11 dogs were unspecific, the most frequent clinical finding being nonpainful progressive abdominal distention. All radiographed dogs had large liver masses; they contained small mineralizations in five. The most frequent ultrasonographic finding was multiple large cavitary masses with or without wall mineralizations. Seven animals received surgical and subsequent medical therapy with albendazole (10mg/kg) and all went into clinical remission. This study reviewed for the first time imaging findings associated with alveolar echinococcosis. The disease has to be included in the list of differential diagnoses in dogs with large, cavitary liver masses, particularly when mineralization is noted.

Myxosarcoma in the eye and brain in a dog.

A male mixed breed dog of unknown age was presented with sudden onset of blindness and a slightly exophthalmic right eye. Ophthalmoscopically, a spherical, pinkish mass protruding from the region of the optic disc into the vitreous was seen in the right eye. Ultrasound and computer tomography demonstrated an extension of the mass into the right retrobulbar space, continuing intracranially to the optic chiasm. Cytologic findings, obtained by ultrasound-guided fine needle aspiration from the retrobulbar space, were consistent with myxosarcoma. On the basis of these findings of a well-delineated mass in the brain stem area, irradiation was planned as the therapy of choice. The dog was treated under general anesthesia using a proton beam at the Paul Scherrer Institute (PSI, Villigen, Switzerland). A curative protocol (56 Gy in 16 fractions over 4 weeks, 3.5 Gy/fraction) was used. Twenty-seven days post radiation therapy the dog was euthanized, as clinical symptoms progressed. Enlargement of the intracranial tumor was seen on a CT study repeated on the day of euthanasia. A gross pathologic and histologic examination were performed and confirmed the diagnosis of a myxosarcoma involving the eye, retrobulbar space of the right side, and the optic chiasm. Post-mortem examination failed to identify any abnormalities or metastases elsewhere in the body.