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Biomedical subjects

J W Nesbit

Publications and source records attributed to J W Nesbit.

At least 19 recordsLinked to original sources
PubMed1999

Spinal nephroblastoma in an Irish wolfhound.

A 1-year-old Irish wolfhound was presented with a history of slowly progressive left pelvic limb paresis. A neurological examination demonstrated bilateral deficits referable to the thoracolumbar spinal cord. Lumbar cerebrospinal fluid contained neoplastic cells. An intradural, extramedullary mass was demonstrated by myelography at the caudal aspect of T13. Surgical excision was abandoned owing to severe macroscopic damage to, and apparent infiltration of, the cord, and the dog was euthanased. The tumour was diagnosed histologically as an extrarenal nephroblastoma. Nephroblastoma should be suspected in young, large-breed dogs with intradural extramedullary masses over spinal segments T10-L2. The prognosis for complete recovery after surgical excision is guarded to poor.

Animals↗
PubMed1999

Cryptococcosis in captive cheetah (Acinonyx jubatus): two cases.

Cryptococcus neoformans is a yeast-like organism associated with pulmonary, meningoencephalitic, or systemic disease. This case report documents 2 cases of cryptococcosis with central nervous system involvement in captive cheetah (Acinonyx jubatus). In both cases the predominant post mortal lesions were pulmonary cryptococcomas and extensive meningoencephalomyelitis. Both cheetahs tested negative for feline immunodeficiency virus and feline leukaemia virus. The organism isolated in Case 2 was classified as Cryptococcus neoformans var. gattii, which is mainly associated with disease in immunocompetent hosts.

Acinonyx↗
PubMed1999

Renal pathology in working dogs in the South African National Defence Force.

Urine analysis, serum biochemical profile and a cortical wedge biopsy for histopathological examination was performed on 42 South African National Defence Force (SANDF) dogs from around the country. The only significant finding on urine analysis and serum biochemistry was a relatively large number (16/42) of dogs with elevated serum inorganic phosphate levels. Histopathology revealed that only 9 of the animals had normal kidneys reflected in the wedge biopsy material, with over 50% of them showing signs of glomerular pathology (primarily mesangioproliferative glomerulonephritis). Other conditions detected histopathologically were haemosiderosis (47% of animals), focal nephrosis (2.4%), membranoproliferative glomerulonephritis (2.4%), focal interstitial nephritis (4.7%) and acute tubular nephrosis (4.7%). The lesions observed were of limited distribution and extent; this histopathological finding may account for the absence of significant abnormalities on urine analysis or serum biochemistry profiles. It appears from these results that a large percentage of the SANDF population would be expected to have mild renal lesions, but that these lesions are not severe enough to lead to clinical signs. The findings of this study are similar to those of randomly selected populations of non-military dogs performed in other areas of the world, which also demonstrated an unexpectedly high incidence of histopathological renal pathology in dogs considered healthy. These lesions may well, however, play a role in later life, and it is recommended that military veterinarians maintain an index of suspicion for renal disease, particularly glomerular disease. The aetiology of the histopathological lesions is unknown.

Animals↗
PubMed1999

Diseases of captive cheetahs (Acinonyx jubatus jubatus) in South Africa: a 20-year retrospective survey.

As part of an ongoing study to determine the basis for high prevalences of veno-occlusive disease, glomerulosclerosis, and chronic lymphoplasmacytic gastritis in cheetahs, a retrospective pathology survey of captive cheetahs in the Republic of South Africa (RSA) was conducted. The RSA population was selected because its genetic composition and captive management were similar to those of the cheetah population in U.S. zoos, in which these diseases are common. For this study, archived pathology materials at the University of Pretoria Faculty of Veterinary Sciences in Onderstepoort and the Faculty of Veterinary Science, MEDUNSA, from 69 cheetahs that died between 1975 and 1995 were reviewed, and prevalences of common lesions were compared with those in the U.S. population. Gastritis associated with Helicobacter-like organisms was the most prevalent disease, accounting for close to 40% of the mortalities, including several cheetahs < 3 yr old. Glomerulosclerosis and veno-occlusive disease also were major causes of mortality in RSA cheetahs. RSA cheetahs also had adrenal cortical hyperplasia, cardiac fibrosis, lymphocytic depletion of the spleen, systemic amyloidosis, and splenic myelolipomas. The presence in the captive RSA cheetah population of the same unusual diseases that are common in U.S. cheetahs suggests a species predilection to develop these diseases in captivity.

Acinonyx↗
PubMed1997

Multiple malignant meningiomas in a young cat.

A 2-year-old cat was presented with generalised muscle tremors and progressive fore- and hindlimb ataxia, 5 months after the initiation of chemotherapy for thymic lymphoma. The lymphoma was treated with combination chemotherapy (cyclophosphamide, vincristine and prednisolone), which resulted in remission. The neurological signs progressed to paralysis and the cat subsequently died. On autopsy, multiple meningiomas were diagnosed, which is an unusual finding. It is possible that the lymphoma chemotherapy resulted in the development of the multiple meningiomas as secondary malignancies.

Animals↗
PubMed1997

Ulcerative pododermatitis in free-ranging African elephant (Loxodonta africana) in the Kruger National Park.

The occurrence of severe lameness in adult African elephant bulls in a shrub Mopane (Colophospermum mopane) ecosystem was investigated. Large ulcers in the soles of at least one front foot were seen in each of the recorded cases. Microscopically, the lesion can be described as a severe, chronic-active, ulcerative, bacterial pododermatitis (complicated by hypersensitivity/septic vasculitis). A variety of bacteria were isolated from these lesions as well as from regional lymph nodes. Streptococcus agalactiae was the most consistent isolate, while Dichelobacter nodosus, the only organism known to be involved with foot disease in domestic ruminants, was isolated from two cases. Contributory factors such as body mass, portal of entry and origin of potential pathogens may have predisposed to the development of the lesions.

Animals↗
PubMed1996

Triphasic nephroblastoma in a horse.

A large abdominal mass in a 3-year-old filly was discovered clinically and removed and examined after the horse had been humanely killed. Histologically, three different tissue types were noted, occurring in equal amounts: epithelium largely in the form of well-differentiated tubules, multifocally distributed cell-dense foci of blastema, and myxoid to fibrous stroma. A diagnosis of triphasic nephroblastoma, a rare tumour in the horse, was made on the basis of microscopical findings. The finding of numerous glomeruloid structures confirmed the diagnosis and assisted in distinguishing the tumour from a teratoma. The histogenesis of nephroblastoma is briefly discussed in the context of the histological and immunohistochemical findings of the case.

Abdominal Neoplasms↗
PubMed1996

Lymphangiomatosis of the pelvic limb in a Maltese dog.

A case of lymphangiomatosis is described affecting the right pelvic limb of an 18-month-old, female Maltese dog. A progressive swelling around the stifle had developed subsequent to a routine tibial crest transposition. The swollen area eventually progressed to involve the entire limb circumferentially, to end abruptly in the mid-metatarsal region. The skin of the affected area was deep red in colour, devoid of hair, and had numerous large, thin-walled vesicles that were easily ruptured and from which a serosanguineous fluid exuded. The swelling pitted on digital pressure and showed fluctuant mobility. The microscopic appearance of biopsied and post mortem material mimicked that of lymphangioma. However, the signalment, clinical presentation and histological features are consistent with a diagnosis of the recently reported variant of human lymphangiomatosis, lymphangiomatosis of the limb.

Animals↗
PubMed1996

Immunophenotypic classification of canine malignant lymphoma on formalin-mixed paraffin wax-embedded tissue by means of CD3 and CD79a cell markers.

Canine malignant lymphoma (CML) is a common lymphoid tumour. Identification of the immunophenotype is of prognostic importance: T-cell lymphomas have a worse prognosis than B-cell lymphomas. Until recently, identification of T- or B-cell lymphomas was undertaken by means of flow cytometry or fluorescent immunocytochemistry on frozen sections. Whilst valid in the research field, these methods are impractical for routine diagnostic histopathology in CML. Commercially available CD3 antibody has been successfully employed in T-cell identification in dogs in formalin-fixed paraffin wax-embedded tissue sections, but the lack of a B-cell marker has been a hindrance until the recent introduction of a commercially available pan-B cell marker, CD79a (DAKO M7051), suitable for diagnostic application upon formalin-fixed paraffin wax-embedded material. Antibody markers to CD3 and CD79a show cross-reactivity across species lines for B cells and T cells respectively. In this group of five selected canine cases, two were identified as B-cell and the other three as T-cell lymphoma, by means of CD3 and CD79a. To the best of our knowledge application of CD79a in cases of CML has not been reported.

Animals↗
PubMed1996

The comparative role of haemoglobinaemia and hypoxia in the development of canine babesial nephropathy.

Renal pathology associated with haemoglobinaemia resulting from Babesia canis infection is ascribed to haemoglobinuria, with or without a contribution from anaemic hypoxia. This study was undertaken to investigate the relative roles of haemoglobinaemia and hypoxia in renal function and pathology in the dog. Three groups of 6 dogs each were used over a 4-day period. The dogs in the 1st group were infused with homologous canine haemoglobin, anaemic hypoxia was induced in the 2nd group, and both treatments were applied in the 3rd group. Full urinalyses, serum urea and creatinine concentrations, fractional clearance of sodium and the activity of urine enzymes, were assessed daily. At the end of the trial period, the glomerular filtration rate (GFR) was determined and kidney specimens collected for light and electron microscopy. In the group with hypoxia only, the urine sediment contained more casts and a greater number of renal tubular epithelial (RTE) cells than in either of the other groups. Hypoxia resulted in greater enzymuria, suggestive of RTE cell pathology, whereas haemoglobinuria did not appear to have any effect on urine enzyme activity. Hypoxia resulted in a decreased GFR. Histological examination revealed a mild, single-cell tubular necrosis in the majority of the animals (all 3 groups), with granular casts in the hypoxic groups. There appeared to be a large individual variation in the ability of the kidney to handle infused haemoglobin. It was concluded that severe haemoglobinaemia did not induce a significant nephropathy, anaemic hypoxia appeared to cause a very mild nephropathy, and the combination of haemoglobinaemia and anaemic hypoxia did not exacerbate this change. These lesions were very different from those described in canine babesiosis.

Animals↗
PubMed1992

Malignant mesothelioma in a seven-week-old puppy.

A case of diffuse malignant peritoneal mesothelioma in a 7-week-old puppy is reported. The puppy presented with a recurrent abdominal effusion. An exploratory laparotomy revealed extensive adhesions. Necropsy findings included pleural thickening, and enlargement of the renal and anterior mediastinal lymph nodes. The microscopic features were typical of primary desmoplastic diffuse mesothelioma of the peritoneum and pleura with secondary lymph node metastasis (renal and anterior mediastinal). The tumour was classified as epithelial in type. The extent of the tumour and the distant metastasis were considered to reflect a high degree of malignancy. A congenital origin was suspected.

Animals↗
PubMed1992

Fatal acute babesiosis in a juvenile wild dog (Lycaon pictus).

Clinical examination of a 75-day-old captive juvenile wild dog suffering from lassitude revealed pale mucous membranes, icterus, laboured respiration, a "water-hammer" pulse and splenomegaly. A peripheral blood smear containing numerous Babesia-infected erythrocytes confirmed the diagnosis of babesiosis. Treatment was unsuccessful and the animal died shortly after receiving a blood transfusion. The findings at necropsy were typical for acute babesiosis and included anaemia, icterus, splenomegaly and haemoglobinuria. In addition, marked atrophy of the thymus and lymph nodes was evident. Microscopic and electron microscopic examination of selected tissues disclosed high parasitaemia with vascular stasis and injury to both endothelial and parenchymal components. It is speculated that vaccination-induced immune incompetence predisposed to development of clinical babesiosis.

Animals↗
PubMed1991

Pox virus infection in captive juvenile caimans (Caiman crocodilus fuscus) in South Africa.

Light grey macules developed on the skin and in the mouths of juvenile caimans, (Caiman crocodilus fuscus) (n = 8), kept in the quarantine section of the reptile park at the National Zoological Gardens, Pretoria, Republic of South Africa. The gross, histopathological and ultrastructural features of the lesions were commensurate with pox virus infection. This outbreak closely resembled the disease described elsewhere in 3 juvenile captive caimans.

Alligators and Crocodiles↗
PubMed1990

Accidental pentobarbital poisoning in a lioness.

A lioness was accidentally poisoned by consumption of meat of a horse euthanased with pentobarbital. The post mortem examination was negative but thin-layer gas-chromatographic and mass-spectrometric methods revealed a pentobarbitone concentration of 1, 14 mg kg-1 in the chloroform extracts of the liver of the animal.

Animal Feed↗
PubMed1990

Salmonellosis in an adult dairy cow.

An outbreak of diarrhoea occurred in a Jersey herd after the introduction of new stock. One of the cows was examined and treated unsuccessfully. Clinical findings included depression, fever, dehydration, congestion, signs of colic and a severe diarrhoea. The post mortem examination revealed emaciation, pseudomembranous enteritis, mesenteric lymphadenopathy and focal disseminated hepatic necrosis. Salmonella typhimurium was isolated from the faeces, mesenteric lymph nodes and liver.

Animals↗
PubMed1988

Mechanisms affecting the development of renal cystic disease induced by diphenylthiazole.

To provide information on the possible influence that hypertension or its treatment might have on the development of cysts in autosomal dominant polycystic kidney disease, we studied the effects of the sodium content of the diet, DOCA-salt hypertension, renovascular hypertension, and the administration of enalapril or furosemide on the development of 2-amino-4-5-diphenylthiazole (DPT)-induced renal cystic disease. DOCA-salt hypertension caused vascular and glomerular lesions and proteinuria, but it did not enhance the development of cysts. Cytogenesis was enhanced in experimental conditions where the renin-angiotensin system is known to be activated. On the other hand, interventions known to suppress the renin-angiotensin system lessened the development of cysts. We hypothesize that this effect might be mediated by intrarenal angiotensin II and its capacity to promote cell growth and to control the postglomerular vascular resistances and the compliance of the renal interstitium.

Animals↗