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Biomedical subjects

N G Wright

Publications and source records attributed to N G Wright.

At least 37 records · Page 2Linked to original sources

Immunity to canine adenovirus respiratory disease: a comparison of attenuated CAV-1 and CAV-2 vaccines.

Four litters of puppies were divided into three groups. One group was vaccinated with a live CAV-1 vaccine and another with a live CAV-2 vaccine. Throat swabs were collected from two dogs in each of these groups to monitor the possible excretion of vaccine virus, but none was found. Both groups, together with the third group of unvaccinated controls, were challenged 17 days later with an aerosol of virulent CAV-2. One dog from each group was killed on the third, fourth, seventh, ninth, 11th and 14th days after challenge. The unvaccinated dogs developed a clinical disease characterised by anorexia, dullness, coughing and tachypnoea. The lungs were consolidated and histological examination revealed the main lesion to be a severe necrotising bronchiolitis. Large amounts of virus were present in the respiratory tissues of these dogs and high titres of virus were isolated from throat swabs. In contrast, both groups of vaccinated dogs remained clinically almost normal with minimal lesions, present for a much shorter period of time. Virus was found on day 4 in the respiratory tissues of one dog vaccinated with CAV-1 but the other vaccinated animals contained little or no virus. In general, the degree of protection afforded by CAV-1 vaccine seemed similar to that provided by CAV-2 vaccine.

Adenoviridae↗

Liquoid-induced renal lesions in the dog.

The role of fibrin in the pathogenesis of renal glomerular scarring in the dog was studied. Fibrin deposition, resulting from disseminated intravascular coagulation, was induced by intravenous injection of Liquoid (sodium polyanethol sulphonate). Thirty-eight puppies were killed from 30 minutes to 39 days after treatment, and the renal lesions examined by light, electron and immunofluorescence microscopy. The major acute lesions in the glomeruli were capillary thrombosis, mesangial and endothelial cell swelling and phagocytosis of fibrin, polymorphonuclear leukocyte infiltration and necrosis. Animals that recovered from this acute phase had focal glomerular scars. Affected glomeruli showed combinations of mesangial enlargement, focal tuft hypercellularity, collagen formation, thickening, wrinkling and duplication of the glomerular basement membranes, and some capsular adhesions. These observations indicate that fibrin deposition can be an important mechanism in glomerular scarring in the dog.

Animals↗

Experimental canine adenovirus glomerulonephritis: persistence of glomerular lesions after oral challenge.

Ten dogs were given canine adenovirus by the non-lethal oral route. Eight dogs were biopsied at 10 days after administration of virus in order to establish the presence of immune-complex glomerulonephritis. At this time, granular deposits of IgG, IgM, C3 and viral antigen were observed in a mesangial location and electrondense deposits were found. The dogs were then killed up to 40 days after receiving virus and, in all cases, deposits of immunoglobulins and complement together with the mesangial proliferative lesions were found to have persisted.

Adenoviridae Infections↗

Membranous nephropathy in the cat and dog: a renal biopsy and follow-up study of sixteen cases.

A morphologic study of biopsy specimens from 16 cases of membranous nephropathy in the cat (11 cases) and dog (five cases) was carried out using conventional light microscopy, immunofluorescence, transmission electron microscopy, and scanning electron microscopy. Depending on the degree of membranous change of the capillary loops and glomerular scarring, each case was graded "mild," "moderately severe," or "advanced." Clinically, most cases were presented showing the nephrotic syndrome, although two cases were presented in chronic renal failure. Most cases were followed through to necropsy after an interval ranging between 2 days and 3 years. In some cases, repeated biopsies were taken during this period.

Animals↗

Membranous nephropathy in the cat: a clinical and pathological study.

A series of 13 cases of feline membranous nephropathy is presented. Two groups were distinguished clinically; eight cats had the nephrotic syndrome and five others were in renal failure but not nephrotic. The definitive diagnosis was based on histological, immunofluorescence and ultrastructural examinations of renal tissue obtained at renal biopsy or necropsy. Glomerular lesions were classified according to the degree of glomerular change into three distinct groups; mild, moderately severe and advanced. A relationship was established between the mild and moderately severe groups and cats with the nephrotic syndrome, and the advanced group and cats in renal failure. Diuretic therapy was satisfactory in initial control of oedema in the nephrotic cases. Monitoring of previously nephrotic cats for up to three years indicated that the disease is progressive, although in some cases it is sufficiently slow for a cat to live a relatively normal life without continuing treatment. The prognosis for cats presented in renal failure is hopeless.

Animals↗

Vaccination against canine bordetellosis: protection from contact challenge.

Eight collie-cross pups, eight weeks old, were inoculated intramuscularly with an aluminum hydroxide adjuvanted preparation of killed Bordetella bronchiseptica; the inoculation was repeated after two weeks. Two weeks after the second inoculation, the vaccinated dogs and a control group of four unvaccinated animals were placed in contact with a group of five pups of similar age which had been experimentally infected with a pathogenic strain of B bronchiseptica by an aerosol method. All four unvaccinated control dogs as well as all five experimentally infected dogs developed a respiratory disease characterised by persistent coughing. Six of the vaccinated dogs remained free from clinical respiratory disease while disease was less severe and of shorter duration in the remaining two than in controls. Only slight changes were found in the lungs of vaccinated animals at necropsy while in the controls there was a severe tracheobronchitis. There was a marked reduction in the numbers of B bronchiseptica isolated from the respiratory tract of vaccinated animals when compared with controls. An aluminium hydroxide adjuvanted vaccine may be of value in controlling naturally occurring canine respiratory disease in which B bronchiseptica is involved.

Animals↗

A study of dogs with kennel cough.

A detailed study of a population of dogs with kennel cough was undertaken. Twenty-seven (77 per cent) of a total of 35 dogs had pathological evidence of respiratory disease in the form of tracheobronchitis with, in some animals, exudative pneumonia. A variety of viral and bacterial agents were isolated from the respiratory tract of diseased dogs but Bordetella bronchiseptica and canine parainfluenza virus SV-5 appeared to be the most significant organisms recovered.

Animals↗

Transmission studies with bovine malignant catarrhal fever.

The intravenous administration of whole blood from a pathologically confirmed field case of bovine malignant catarrhal fever (MCF) resulted in the appearance of the disease in three of five experimental calves 18 to 28 days later. Infection was maintained by serial calf transmissions, and produced clinical and pathological changes identical to those of the field disease for a total of 10 passages. The sixth passage involved the simultaneous infection of 10 calves from a single donor animal; six of the 10 recipients developed the typical disease after incubation periods ranging from 20 to 36 days and in each of these MCF was confirmed by pathological examination. In addition, clinical and pathological changes in the four other calves which were slaughtered either seven or 14 days post-infection suggested that they too would have developed typical clinical signs had they been allowed to survive for the necessary length of time. The results of a detailed study of the onset, progress and duration of the clinical signs of experimentally induced MCF are presented and the opportunity has been taken to discuss the available information regarding the transmission of MCF under experimental conditions and in the field.

Animals↗

Vaccination against Bordetella bronchiseptica infection in dogs using a heat-killed bacterial vaccine.

A group of eight-week-old dogs was inoculated with a heat-killed suspension of Bordetella bronchiseptica by the intramuscular route on two occasions at an interval of two weeks. All vaccinated animals developed high circulating agglutinin titres by two weeks after the second inoculation at which time the vaccinated dogs and a comparable group of unvaccinated animals were challenged by exposure to an aerosol of live B bronchiseptica. Both vaccinated and unvaccinated dogs subsequently developed clinical respiratory disease characterised by persistent coughing but the onset of disease in vaccinated animals was delayed by up to five days when compared with the controls. B bronchiseptica was isolated from the nasal cavity, tracheobronchial tree and lung parenchyma of vaccinated and control dogs.

Animals↗

Vaccination against canine bordetellosis using an aluminum hydroxide adjuvant vaccine.

Six collie dogs, eight weeks old, were inoculated intramuscularly with an aluminium hydroxide adjuvanted preparation of killed Bordetella bronchiseptica; the inoculation was repeated after two weeks. Two weeks after the second inoculation, the vaccinated dogs and a comparable group of six unvaccinated animals were challenged by exposure to an aerosol of pathogenic B bronchiseptica. All six unvaccinated control dogs developed respiratory disease characterised by persistent coughing. In contrast, four of the vaccinated dogs remained free from clinical respiratory disease while, in the other two dogs, disease was less severe and of shorter duration than in controls. At necropsy, there were only slight changes in the lungs of vaccinated dogs but in controls there was a severe tracheobronchitis with areas of exudative pneumonia. Bacteriological examination showed a marked reduction in the numbers of B bronchiseptica isolated from the respiratory tract of vaccinated animals compared with controls. An aluminium hydroxide adjuvant vaccine may be of value in controlling naturally occurring respiratory disease in dogs in which B bronchiseptica is involved.

Adjuvants, Immunologic↗

Chronic renal failure in dogs: a comparative clinical and morphological study of chronic glomerulonephritis and chronic interstitial nephritis.

Chronic renal disease is an important clinical problem in dogs. Until recently, diffuse renal fibrosis with chronic renal failure has been attributed mainly to chronic interstitial nephritis, itself considered to be the end stage of acute leptospiral nephritis. A clinical and morphological analysis of eight cases of chronic glomerulonephritis is described and a comparison made with eight dogs suffering from severe chronic interstitial nephritis. Clinically and biochemically, the two diseases were virtually indistinguishable, both resulting in uraemia. A possible distinguishing feature of chronic interstitial nephritis was the anaemia which was absent from chronic glomerulonephritis cases. Morphologically, the two diseases appeared to be distinguishable on three grounds; the pattern and severity of fibrosis, the degree of fibrin deposition and the immunofluorescence findings.

Animals↗