Experimental study of a new open stent for vessel banding in a swine model: long-term results.

AIM: A new stent was designed, conceived for being placed externally around blood vessels to perform vessel banding in a much simple and fast way. In fact it requires the dissection of a single segment of the aortic wall, as its mechanical features allow it to slide on the tunica adventitia. After previous tests (ex vivo and in vivo test), the new stent has been evaluated in vivo long-term study. METHODS: In female pig of average weight of 60 kg, after placement of endoprosthesis in infrarenal abdominal aorta, immediately below renal arteries, aortic banding was performed with new stent at the level of each end of endoprosthesis, identified under fluoroscopic guidance. Pigs were followed up for six months, and acetylsalicylic acid was administrated: 100 mg once a day. After six months, histological evaluation of explanted abdominal aorta was performed. RESULTS: New stent made the aortic banding simple and fast. Postoperative course was uneventful. Histological results were similar to previous 10-week survival tests and not damages of aortic wall were observed. CONCLUSION: Positive outcome of three last long-term survival tests, as of all those ex vitro and in vivo tests previously performed, makes conceivable further scientific investigation and trials.

Neuronal vacuolation, myelopathy and laryngeal neuropathy in a mixed-breed dog.

A bilateral and symmetrical neuronal vacuolation associated with spinal cord white matter degeneration and laryngeal neuropathy was observed in a 12-week-old male mixed-breed dog with a history of progressive pelvic limbs ataxia. On clinical examination, signs included inspiratory stridor, spinal ataxia, tetraparesis, and proprioceptive deficits more severe in the pelvic limbs. Examination of the larynx showed bilateral laryngeal paralysis and electromyography revealed fibrillation potentials restricted to the intrinsic laryngeal muscles. Clinical and pathological findings resembled the syndrome of neuronal vacuolation and spinocerebellar degeneration described in Rottweiler dogs. This is the first report of a similar disorder in a dog different from Rottweiler.

Magnetic resonance imaging and pathological findings in a case of canine idiopathic eosinophilic meningoencephalitis.

A case of idiopathic eosinophilic meningoencephalitis in a six-month-old male Maremma shepherd dog is reported. The dog was referred with a four month history of progressive weakness and depression with loss of trained habits. Tendency to recumbency, disorientation, visual impairment, bilaterally decreased menace response and hindlimb conscious proprioception deficits were detected. Magnetic resonance imaging showed a diffuse hypointense signal involving the cerebral grey matter with enlargement of the cerebral sulci on T1-weighted and fast fluid-attenuated inversion recovery (FLAIR) sequences consistent with a diffuse necrosis or atrophy of the cortical grey matter. Histological examination revealed severe inflammatory infiltration mainly composed of eosinophils and macrophages in the subarachnoid space and in the superficial layer of the cerebral cortex where parenchymal rarefaction and necrosis of neurones were also evident. No parasites, cysts or fungi were detected, and an immunologically mediated disorder was suspected. Magnetic resonance imaging may represent a useful diagnostic tool to differentiate idiopathic eosinophilic meningoencephalitis from other inflammatory brain diseases of young dogs.

Natural vectors of dirofilariasis in rural and urban areas of the Tuscan region, central Italy.

Entomological investigations by means of dog- and human-baited traps were carried out in summers 2000-2002 in urban and rural areas of the Tuscan region in central Italy. The aim of the study was to define the mosquito species involved in the transmission of Dirofilaria nematodes and to assess the risk that their presence might represent for animal and human health. Nocturnal fieldwork on host-seeking activity and feeding preferences was followed by microscopic identification of the mosquito species attracted and by molecular identification of Dirofilaria parasites in mosquitoes. In total, 3,611 mosquito females belonging to 12 species, largely represented by Culex pipiens L. and Aedes caspius (Pallas), were caught. Some females of each species collected fed on the dogs, indicating their possible role as an intermediate host, but filarial DNA was found only in Cx. pipiens, Anopheles maculipennis s.l. (Meigen), and Coquillettidia richiardii (Ficalbi). In rural environments, the DNA evidence indicated the presence of infective larvae of Dirofilaria immitis, whereas in urban areas, infective larvae of Dirofilaria repens were present. The role of Cx. pipiens as a vector for heartworm disease and subcutaneous infections in natural and artificial environments was confirmed, whereas Ae. caspius seemed refractory to the infection. The different role of the collected species is discussed. The vector competence of An. maculipennis and Cq. richiardii needs further investigation, because the importance of these species poorly represented, and the role of species such as Aedes albopictus (Skuse), characterized by a dominant diurnal activity pattern, has to be evaluated.

Clinicopathological features of globoid cell leucodystrophy in cats.

Clinical and pathological findings consistent with globoid cell leucodystrophy (GLD) were evaluated in two domestic shorthaired cats, aged 3 and 4 months. Both showed neurological signs mainly characterized by progressive pelvic limb ataxia, paraplegia with loss of deep pain perception in the pelvic limb, and intentional tremors of the thoracic limbs. Pathological changes affecting the central and peripheral nervous systems were characterised by diffuse, bilateral and symmetrical myelin loss, and marked astrogliosis. In the leucodystrophic areas there was perivascular accumulation of large PAS-positive, non-metachromatic macrophages (globoid cells), with intracytoplasmic accumulation of crystalloid tubular aggregates. Peripheral nerves showed demyelinating features with thin myelin sheaths, myelin splitting, and ballooning; the nerve fibres had bizarre shapes due to the presence of pale inclusions in the Schwann cells. GLD in cats shares clinical and pathological features with the disease described in other animals and human beings. The neurological signs differed from those of other feline inborn neurometabolic diseases and cerebellar hypoplasia.

Meningeal carcinomatosis in two cats.

Multifocal to diffuse meningeal infiltration by neoplastic epithelial cells was observed in two aged cats with neurological signs and a history of surgical ablation of the auricular pinnae because of the presence of squamous cell carcinoma. In both cats, examination of the external ear canals revealed neoplastic lesions consistent with squamous cell carcinoma, but no changes of the tympanic bullae were noted. In one cat, post-mortem examination revealed marked thickening of the dura mater and infiltration of the arachnoid layer by cytokeratin-positive, neoplastic epithelial cells. In the other cat, no macroscopic brain lesions were noted, but multifocal dissemination of neoplastic epithelial cells to the leptomeninges was observed histologically. Several pathways by which neoplastic cells can reach the meninges have been suggested and haematogenous dissemination was considered most likely in these cats. Squamous cell carcinoma is the most common cutaneous malignant neoplasm in cats and meningeal carcinomatosis can be considered a rare complication.

Degenerative myelopathy associated with cobalamin deficiency in a cat.

A severe myelopathy was observed in a 9-year-old neutered male cat with a clinical history of chronic pancreatitis associated with deficiency of serum cobalamin and folates concentrations, and progressive spinal ataxia. The spinal cord lesions mainly involved the dorsal columns of the caudal cervical and cervico-thoracic segments, and were characterized by diffuse vacuolated myelin sheaths and axonal degeneration, marked gliosis, fibrosis and presence of gitter cells. The pancreas showed severe atrophy of the exocrine tissue, periductular fibrosis and infiltration of inflammatory cells, consistent with chronic interstitial pancreatitis. This condition can be accountable for cobalamin deficiency, as the pancreas is the only source of intrinsic factor in cats. The spinal cord lesions in the cat of this report resembled the subacute combined degeneration of the spinal cord described in human beings with cobalamin deficiency and hence a similar pathogenetic mechanism is hypothesized.

Intramedullary hemangioblastoma in a dog.

A 6-year-old male Pointer dog was presented with a 4-week history of progressive hind-limb stiffness. Magnetic resonance imaging demonstrated a focal intramedullary lesion at T1 level with a pattern of ring contrast enhancement. At necropsy, a circumscribed intramedullary reddish-gray tumor was observed. Microscopically, the tumor was composed of thin-walled capillaries lined by endothelial cells and separated by pleomorphic cells (stromal cells) with a moderate degree of anisokaryosis. Immunohistochemically, the endothelial cells were positive for factor VIII-related antigen and the stromal cells were positive for neuron-specific enolase and vimentin. GFAP-positive astrocytes were occasionally observed within the tumor. Both endothelial and stromal cells were negative for synaptophysin, S-100 protein, pankeratin, smooth muscle actin, CD34, CD68, alpha1-antichymotrypsin, and lysozyme. The tumor showed considerable morphologic and immunohistochemical similarities with human hemangioblastoma, and hence the inclusion of this tumor type within the primary neoplasms of the canine central nervous system is suggested.

Diagnosis of paratuberculosis in naturally infected goats.

A survey was carried out to verify if an immunohistochemical method associated with agar gel immunodiffusion (AGID) will establish a firm diagnosis of caprine paratuberculosis. One hundred and thirty-six goats were tested by AGID for antibodies against Mycobacterium avium subsp. paratuberculosis at two different times: the first time 22 (19.1%) were positive and the second time 25 (18%). One seronegative goat with severe diarrhea and 5 seropositive goats, two of which showing similar clinical signs, were sacrificed and necropsied. Samples were taken from small intestine, liver, spleen, mesenteric lymph nodes for bacteriological, histological and immunohistochemical examinations. M.a. paratuberculosis was isolated from intestine samples of 4 seropositive goats and from mesenteric lymph nodes of one seropositive goat; the microorganism was not isolated from samples of one seropositive and the seronegative animals. Ziehl Neelsen staining showed acid-fast bacilli in macrophages of the 5 seropositive animals and the immunohistochemical method for M. a. paratuberculosis detected bacterial antigen in the same samples.

Pathological and immunohistochemical studies of choroid plexus carcinoma of the dog.

Choroid plexus carcinomas in four dogs (three male, one female) aged small middle 2.5 to 10 years, were examined by light microscopy and immunohistochemistry. The dogs showed progressive neurological signs including ataxia, seizures, vestibular disease and cranial nerve deficits, lasting for several months in some cases. Primary tumours were localized in the lateral (one case), third (one case), and fourth (two cases) ventricles. Hydrocephalus was evident at post-mortem examination in one case. In two cases the neoplastic cells closely resembled the structure of normal choroid plexus, with a distinct papillary pattern, composed of well-differentiated columnar epithelium. In the other two cases, cellular pleomorphism, nuclear atypia, increased mitotic activity and necrosis were observed. In all cases, dissemination of neoplastic cell clusters was detected within the subarachnoid space or the ventricular cavity. Immunohistochemical examination showed a multifocal labelling pattern for pankeratin and cytokeratin AE1 and diffuse vimentin positivity in poorly differentiated tumours. Well-differentiated choroid plexus carcinomas showed multifocal immunoreactivity for cytokeratin AE3, multifocal to diffuse immunoreactivity for vimentin and occasional positivity for carcinoembryonic antigen. Epithelial membrane antigen, Ber EP4 and S-100 were negative in all cases. Glial fibrillary acidic protein labelling occurred only in a single, poorly differentiated tumour. Occasional reactions for proliferating cell nuclear antigen and MIB-1 were seen in two cases. It was concluded that at least two morphological and possibly phenotypic subtypes (well-differentiated and anaplastic) of choroid plexus carcinoma of the dog could be identified.

Necrotizing cerebellitis due to Neospora caninum infection in an old dog.

A severe, necrotizing, non-suppurative inflammation of the cerebellum associated with Neospora caninum infection was identified in a 14-year-old male Labrador Retriever. On presentation, clinical signs included mild depression and head tremor, marked ataxia of both thoracic and pelvic limbs, and abnormal postural reactions. In the central nervous system, inflammatory lesions were mainly restricted to the cerebellar leptomeninges and cerebellar cortex, which appeared necrotic and atrophic. Protozoal organisms were positively stained with an anti-N. caninum antibody in an immunohistochemical procedure.

Cerebellar granuloprival degeneration in an Italian hound.

A severe atrophy of the cerebellum was observed in a 7-month-old male Italian hound with a history of progressive ataxia and head tremor from the age of 3 months. On clinical examination, signs included severe hypermetric gait, head tremors and proprioception deficits in all limbs. At necropsy, a pronounced symmetrical reduction in size of the cerebellum was the only gross lesion observed. Histological examination of the cerebellum revealed marked thinning of the granular and molecular layers with almost complete loss of granule cells. Purkinje cells had normal morphology and distribution. These findings differ from those of previous reports of cerebellar cortical abiotrophy in dogs, which were mainly characterized by prominent Purkinje cell degeneration and loss.

Pathologic and immunohistochemical findings in naturally occuring West Nile virus infection in horses.

The pathologic and peroxidase immunohistochemical features of West Nile flavivirus (WNV) infection were compared in four horses from the northeastern United States and six horses from central Italy. In all 10 animals, there were mild to severe polioencephalomyelitis with small T lymphocyte and lesser macrophage perivascular infiltrate, multifocal glial nodules, neutrophils, and occasional neuronophagia. Perivascular hemorrhages, also noted macroscopically in two animals, were observed in 50% of the horses. In the four American horses, lesions extended from the basal nuclei through the brain stem and to the sacral spinal cord and were more severe than the lesions observed in the six Italian horses, which had moderate to severe lesions mainly in the thoracolumbar spinal cord and mild rhombencephalic lesions. WNV antigen was scant and was identified within the cytoplasm of a few neurons, fibers, glial cells, and macrophages. WNV infection in horses is characterized by lesions with little associated antigen when compared with WNV infection in birds and some fatal human infections and with other important viral encephalitides of horses, such as alphavirus infections and rabies.

Necrotizing meningoencephalitis associated with cortical hippocampal hamartia in a Pekingese dog.

A 4-year-old male Pekingese dog was referred to the clinic with a history of recurrent seizures and progressive abnormal gait and behavior, which did not respond to treatment. At necropsy, a large cortical defect in the right temporo-parietal cortex, malacia of subcortical white matter, right basal nuclei, and capsula interna, as well as abnormalities of the right hippocampus were observed. Histological examination of the brain revealed moderate to severe nonsuppurative meningoencephalitis in the left cerebral hemisphere and extensive infarction-like lesions with milder inflammation in the right hemisphere. In the right hippocampus, the pyramidal cells were arranged in a gyrus-like pattern and intermingled with gemistocytic and fibrillary astrocytes. The histopathological features of the inflammatory lesions were consistent with necrotizing meningoencephalitis and resembled those described in so-called Pug dog encephalitis. The hippocampal changes were interpreted as dysplasia (monolateral hippocampal cortical hamartia), unrelated to clinical signs and necrotizing inflammatory lesions.

Clinical and neuropathological features of West Nile virus equine encephalomyelitis in Italy.

West Nile (WN) virus infection is a mosquito-borne flavivirosis endemic in Africa and Asia. Clinical disease is usually rare and mild and only in a few cases the infection causes encephalomyelitis in horses, fever and meningoencephalitis in man. We report here the clinical and pathological findings in an epidemic of the disease involving 14 horses from Tuscany, Italy. All cases were observed from August to October 1998. Affected horses showed ataxia, weakness paresis of the hindlimbs and, in 6 cases, there was paraparesis progressing to tetraplegia and recumbency within 2 to 9 days. Eight animals recovered without any important consequences. Serological investigations revealed positivity to WN virus in all the 14 horses and the agent was isolated from the cerebellum and spinal cord of an affected horse. Postmortem examination was carried out on 6 horses. The neuropathological pattern was that of a mild to moderate, nonsuppurative polioencephalomyelitis with constant involvement of the ventral horns of the thoracic and lumbar spinal cord, where focal gliosis and haemorrhage were also apparent in some cases. Differential diagnoses with other equine viral encephalomyelitides are discussed. Climatological and environmental characteristics of the geographic area in which the outbreaks occurred suggest the existence of suitable conditions for the development of the disease. This is the first report of WN virus equine encephalomyelitis in Italy.

A case of narcolepsy-cataplexy associated with distemper encephalitis.

Narcolepsy associated with localized brain lesions is described in a 10-month-old Argentine Dogo. Neurological examination and MRI study suggested an inflammatory lesion of the left frontal lobe. Postmortem examination revealed diffuse encephalitis in the forebrain and marked necrotic lesions in the ventral pontine area. Immunohistochemistry for distemper virus antigen showed positive staining of the cytoplasm of many neurones of the pons and cerebral cortex. The pathological pattern was suggestive of post-vaccinal distemper encephalitis and the localization of the lesions was consistent with the neurological syndrome shown by the animal. At any event, the possibility of coincidental findings of distemper encephalitis and idiopathic narcolepsy must be accounted for.

Hydrocephalus with periventricular encephalitis in the dog.

A 3-month-old female Dalmatian dog and a 2.5-month-old Poodle dog were referred with a sudden onset of neurological syndrome consistent with hydrocephalus. Clinical signs included depression, severe ataxia, eye abnormalities and skull enlargement in one case. Postmortem examination revealed severe internal hydrocephalus with cavitation of the cerebral white matter associated with necrotizing and inflammatory lesions of the periventricular nervous tissue. Although no bacteria were isolated from cerebrospinal fluid and no infectious agents were detected in the brains, an infectious etiology was postulated.

Pathology of naturally acquired Angiostrongylus vasorum infection in the red fox (Vulpes vulpes).

199 out of 509 foxes culled in a rabies control scheme, were shown to be infected with the metastrongylid parasite Angiostrongylus vasorum. Pathological lesions associated with angiostrongylosis in the fox are described and compared to reported lesions of A. vasorum infection in the dog. The lesions observed in the foxes seemed to be less severe and mainly confined to the ventral parts of the lung lobes which showed granulomatous pneumonia. Right ventricular hypertrophy of the heart was present in all infected foxes. It is believed that the fox population represents an important reservoir of A. vasorum.

Increase of serum lipid-associated sialic acid concentration in dogs with neoplasms.

Serum concentrations of lipid-associated sialic acid (LASA) were determined in sera obtained from 26 apparently healthy dogs (group 1), 56 dogs with nonneoplastic disorders (group 2), and 100 dogs with neoplasms (benign [group 3], malignant [group 4]), using a simple, reliable, rapid spectrophotometric procedure. The LASA concentrations were significantly increased (P less than 0.01) in group 4 dogs (malignant neoplasms) when compared with those in dogs from groups 1, 2, and 3. The sensitivity of the test was between 71.5% and 100%, and specificity was 92.3% for group 1, 67.8% for group 2, and 80.6% for group 3. A preliminary study concerning variations of serum LASA values as a marker after surgical treatment of tumor showed a good correlation between effectiveness of therapy and serum LASA concentrations.