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Biomedical subjects

R J Higgins

Publications and source records attributed to R J Higgins.

125 records · Page 7Linked to original sources
PubMed1980

Persistent in vitro interaction of virulent and attenuated canine distemper virus with bovine cells.

Bovine macrophage and non-macrophage cultures were infected with either virulent or attenuated canine distemper virus (CDV). Macrophages were resistant to virulent CDV; however, they supported growth of the attenuated virus. Non-macrophage cultures supported growth of both virus variants in a persistent, non-lytic manner. Major differences between these two systems of in vitro viral persistence were seen in the host cell spectrum of progeny virus and the outcome of cocultivation experiments with Vero cells. Results obtained indicate that in vivo virulence of CDV is not linked to maturation in a macrophage, but rather, propagation in a given cell culture system results in selective growth of virulent or attenuated viral mutants. It is further concluded that in vivo virulence and in vitro growth potential of CDV are disparate properties of the virion.

Animals↗
PubMed1980

Virulence of tissue culture-propagated canine distemper virus.

Virulence of canine distemper virus (CDV) adapted to in vitro growth in Vero or bovine cells was determined by inoculation into CDV-susceptible neonatal gnotobiotic dogs. When compared with dogs given virulent R252-CDV, Vero R252-CDV was attenuated at passage level 14. In contrast, dogs inoculated with bovine R252-CDV at the same passage level experienced rapid fatal neurological disease. Virulence was not linked to ability to infect or replicate in canine pulmonary macrophage cultures. Retention of virulence by bovine R252-CDV is unique and worthy of further study.

Animals↗
PubMed1980

Plasma phase viremia in canine distemper virus infection.

Plasma samples from gnotobiotic pups infected with R252 canine distemper virus at 7 days of age contained free infective virus when titrated on canine pulmonary macrophage cultures. Virus was detected 7 days after infection and increased thereafter. Platelets may be involved in leukocyte-free viremia. The present study indicated that the method of dissemination of the virus in vivo involves plasma and canine distemper virus-infected leukocytes.

Animals↗
PubMed1977

Neurofibrillary accumulation in the zebra (Equus burchelli).

Two young zebra siblings from consecutive pregnancies suffered from neurological disease, characterized by ventral deviation of the neck and tetraparesis which progressed to tetraplegia within a few weeks. On histological examination widespread neuronal degeneration was observed in the ventral horns of the spinal cord and in the lower brain stem. Ultrastructurally the neuronal degeneration was characterized by accumulation of neurofibrillary material resembling neurofilaments. The findings are compared to other diseases with neurofibrillary accumulation in man and animals.

Animals↗
PubMed1977

Internal hydrocephalus and associated periventricular encephalitis in young dogs.

Six dogs that had a sudden onset and rapid progression of neurological signs with enlargement of the cranial vault at 6--8 weeks old were believed to have congenital hydrocephalus. There were severe inflammatory and necrotizing lesions in periventricular sites in the brain. A bacterial infection may have been the cause of this process.

Animals↗
PubMed1976

Neoplasms of mesenchymal origin in the spinal cord and nerve roots of three dogs.

Clinicopathological findings of three different neoplastic conditions involving the spinal cord and nerve roots in three dogs are described. One sarcomatous intra-medullary tumor closely associated with the vasculature was classified as a reticulum cell sarcoma of the spinal cord. The second case had massive and widespread neoplastic proliferation of reticulohistiocytic cells around the perineurinal vessels of many spinal nerve roots. The process was classified as a primary neoplastic reticulosis of the spinal roots. Multiple highly malignant tumors, infiltrating the spinal cord were found in one thoracic and several lumbosacral spinal nerve roots in the third case. These were considered to be anaplastic neurofibrosarcomas because of high collagen content, intact nerve fibers, whorl formation, and the tendency to palisade in some areas.

Animals↗
PubMed1976

Fibrocartilaginous emboli as the cause of ischemic myelopathy in a dog.

Acute hemiplegia and Horner's syndrome developed in a 6-year-old female black Labrador Retriever 24 hours after a day of exercise. Radiographic, cerebrospinal fluid, and electromyographic studies did not detect the site or nature of the suspected cervical lesion. The dog showed no improvement after evaluation for 5 days on corticosteroid and antibiotic therapy. Gross and microscopic examination revealed the presence of an ischemic infarct in the C6 segment of the cervical spinal cord and associated fibrocartilaginous emboli. The nature of the clinical signs and the pathologic findings in this case are similar to previous reports of human and canine cases.

Animals↗
PubMedDate not supplied

Modification and application of a Pelorus Mark III stereotactic system for CT-guided brain biopsy in 50 dogs.

The Pelorus Mark III Stereotactic System is a commercially available device for CT-guided stereotactic brain biopsy in people. With relatively minor modifications, this device was used to safely and accurately perform CT-guided stereotactic brain biopsies in 50 dogs with intracranial lesions. Modifications were necessary to accommodate a 90 degree shift in orientation of the canine head compared to the human head during the imaging phase of the procedure, and to facilitate other phases of the biopsy procedure that are affected by the uneven and variable topography of the canine skull. Description of a typical CT-guided brain biopsy procedure in dogs using the modified Pelorus Mark III Stereotactic System is provided. Accuracy of biopsy needle placement was determined by comparing the x, y and z coordinates of the biopsy target site with the actual coordinates of the needle tip on CT images. Mean needle placement error was 3.5 +/- 1.6 mm. Needle placement error was not significantly related to operator experience, dog size (body weight), or needle path length, however, needle placement error was significantly affected by lesion location.

Animals↗
PubMedDate not supplied

CT-guided brain biopsy using a modified Pelorus Mark III stereotactic system: experience with 50 dogs.

This report describes the results of CT-guided stereotactic brain biopsies performed on 50 consecutive dogs using a modified Pelorus Mark III Stereotactic System. Based on available histopathologic samples (stereotactic biopsy [n = 50], surgery [n = 17], necropsy [n = 9]) the patient population consisted of 34 dogs with primary brain tumors, 2 with invasive nasal adenocarcinomas, and 13 with non-neoplastic brain lesions. Brain tissue was not obtained from one dog. In 22 dogs a final diagnosis was made from tissue subsequently obtained from surgical resection or at necropsy. The final diagnosis was in agreement with the stereotactic biopsy diagnosis in 20 of these 22 dogs. In 17 other dogs without follow-up, stereotactic biopsy provided a diagnosis of a specific primary brain tumor subtype. Postoperative complications associated with the biopsy procedure were assessed in 41 dogs. The other 9 dogs either went directly to surgery (n = 7) or were killed (n = 2) immediately after the biopsy procedure. Thirty-six dogs recovered without apparent clinical complications. Postoperative clinical complications in the remaining 5 dogs included transient epistaxis (1 dog), transient exacerbation of cerebellar signs (1 dog), obtundation progressing to coma (1 dog), and medically uncontrollable seizures (2 dogs). The latter 3 dogs with severe neurologic complications all had large primary brain tumors and had been receiving high doses of phenobarbital and glucocorticoids to control seizures at the time of biopsy. These results suggest that this CT-guided biopsy procedure can provide an accurate pathologic diagnosis of brain lesions detected by CT and MR neuroimaging. Further refinement of both technique and case selection is expected to reduce the rate of clinical complications and to improve the accuracy of the procedure.

Adenocarcinoma↗
PubMedDate not supplied

Epidemiology of equine protozoal myeloencephalitis in North America based on histologically confirmed cases. A report.

Following a workshop on equine protozoal myeloencephalitis (EPM) convened at the Veterinary Medical Forum of the American College of Veterinary Internal Medicine in 1988, this survey of EPM in North America was developed. It is based upon 364 histologically confirmed case records from California, Florida, Illinois, Kentucky, New York, Ohio, Oklahoma, Ontario, Pennsylvania, and Texas up to 1988. The highest rate of infection was found in young Thoroughbred, Standardbred, and quarter horses. Differences in geographic location, sex, and month (season) of infection were not discernible. This report, the first comprehensive survey of EPM in North America, is intended to serve as a basis for evaluating future changes in prevalence and spread of EPM.

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