Search PubMed⌕ Search

Biomedical subjects

W F Jarrett

Publications and source records attributed to W F Jarrett.

At least 37 records · Page 2Linked to original sources
PubMed1986

Papillomavirus infection in cattle: viral and chemical cofactors in naturally occurring and experimentally induced tumours.

Six different types of bovine papillomavirus (BPV-1 to BPV-6) have been identified and classified into two subgroups: subgroup A, which induce fibropapillomas, and subgroup B, which induce true epithelial papillomas. BPV-4, a member of subgroup B, is the aetiological agent of papillomas of the upper alimentary canal, which can become a focus for transformation to squamous-cell carcinomas in animals feeding on bracken fern. Strong circumstantial evidence suggests that the progression to malignancy is due to the interplay between BPV-4 and carcinogen(s) present in the fern. The carcinomas of the upper alimentary canal are often accompanied by adenomas and adenocarcinomas of the lower bowels, and by carcinomas and hemangiosarcomas of the urinary bladder. Bracken-grazing animals are also heavily immunosuppressed. Florid papillomatosis of the upper alimentary canal and cancers of the urinary bladder have been experimentally reproduced in animals either kept on a diet of bracken or immunosuppressed with azathioprine. Several bladder cancers contained multiple episomal copies of BPV-2 DNA, suggesting that this virus, or its genome, can be present in a latent form, and that it can be implicated in malignant transformation. Further indication of latent infection is provided by the onset of skin warts in papillomatosis-free animals. These warts developed at sites of damaged skin and harboured either BPV-1 or BPV-2. BPV-4 DNA has not been found in the naturally occurring cancers of the upper alimentary canal and of the lower bowels, except in one tongue carcinoma and one transforming papilloma, indicating that the viral genome is not required for the maintenance of the malignant state in the alimentary canal.

Animal Feed↗
PubMed1986

Viral DNA sequences detected in a hamster liposarcoma induced by bovine papillomavirus type 4.

Following intradermal inoculation of bovine papillomavirus type 4 (BPV-4) into a Syrian hamster, a liposarcoma developed at the inoculation site 20 months later. The DNA of this tumour contained multiple copies of the BPV-4 genome which existed in a free unintegrated state. Unintegrated viral DNA and viral DNA isolated from virus particles from bovine alimentary tract papillomas revealed identical cleavage patterns with CpG methylation-resistant and -sensitive restriction enzymes: apparently there was no gross methylation of CpG sites in either case. The entire BPV-4 genome appeared to be represented in the tumour DNA.

Animals↗
PubMed1985

A new transmissible agent causing acute hepatitis, chronic hepatitis and cirrhosis in dogs.

There is a hepatitis of dogs which occurs in acute, persistent and chronic forms. Histological studies of spontaneous cases suggested that several apparently diverse hepatic diseases might be stages of one process. This was also implied by follow up studies and case histories: acute non-lethal episodes were followed later by the development of chronic hepatitis, cirrhosis and liver failure. Serum was taken and homogenates of liver were made from three field cases representing different putative temporal stages of the complex. These were injected into experimental dogs and a hepatitis was induced in all. The cytopathological and histological changes were the same in all animals and were identical to field cases. Acute lethal disease and persistent infections were produced. Two second passages were carried out and an identical condition was induced, characterised by recurrent episodes of subclinical hepatitis and persistent infection. It is suggested that the disease might be named canine acidophil cell hepatitis in view of the pathognomonic cytopathology. Specific morphological criteria have been established for this hepatitis.

Alanine Transaminase↗
PubMed1985

The presence of bovine papillomavirus type 4 DNA is not required for the progression to, or the maintenance of, the malignant state in cancers of the alimentary canal in cattle.

In the Western Highlands of Scotland there is a very high incidence of alimentary cancers in cattle. The carcinomas of the upper alimentary canal are found in association with virus-induced benign papillomas, and transformation of papillomas to carcinomas has been observed. Strong circumstantial evidence suggests that the progression to malignancy is due to the interplay between the virus, bovine papillomavirus type 4 (BPV-4), and carcinogen(s) present in bracken fern, which infests the marginal upland grazing grounds. The carcinomas are often accompanied by adenomas and adenocarcinomas of the lower bowels. To elucidate the role of the virus in the transformation process, we have analysed several malignancies of the alimentary canal, and have detected the viral genome in only one case of transforming papilloma of the oesophagus and one case of carcinoma of the tongue. We conclude that, although required for the induction of papillomas, the presence of the BPV-4 DNA is not necessary for the progression to, or the maintenance of, the transformed state.

Animals↗
PubMed1985

A cutaneous fibropapilloma from a red deer (Cervus elaphus) associated with a papillomavirus.

A cutaneous fibropapilloma was found on a Scottish red deer (Cervus elaphus), and a papillomavirus was isolated from it. The virus appeared to be related to bovine papillomavirus type 1 (BPV1) or type 2 (BPV2) because: (i) it cross-reacted in peroxidase-antiperoxidase tests with antisera raised against these virions; (ii) BPV1 and BPV2 DNAs cross-hybridized to the red deer papillomavirus in situ; and (iii) BPV1 and/or BPV2 DNA cross-hybridized to the red deer papillomavirus DNA on Southern blots under conditions of high stringency. These tests also revealed a unique restriction enzyme cleavage pattern for the red deer papillomavirus DNA.

Animal Diseases↗
PubMed1984

Papillomas of the teats and udder of cattle and their causal viruses.

An abattoir survey was carried out on 1657 cattle to determine the incidence and parameters of teat and udder papillomas and their causal viruses. Recent research has characterised six different bovine papillomaviruses of which three have been found to be particularly associated with teat tumours. Of the population studied 37.3 per cent had teat warts and 86.2 per cent of these had multiple infections; 28.4 per cent had papillomas attributed to bovine papillomavirus 1, 88.5 per cent to bovine papillomavirus 5 and 92.3 per cent to bovine papillomavirus 6. There was no predilection site between teats. Herefords and their crosses dominated the breed incidence and showed the highest numbers of warts but it was not possible to make a realistic comparison with other breeds. Dairy cattle were poorly represented. Bovine papillomavirus 4 was never found and from this it was concluded that there is no association between alimentary and teat papillomas. The implications of these findings in terms of prophylaxis and control are discussed.

Animals↗
PubMed1984

A novel bovine papillomavirus (BPV-6) causing true epithelial papillomas of the mammary gland skin: a member of a proposed new BPV subgroup.

A papillomavirus has been isolated from frond epithelial papillomas of the bovine udder. It is clearly distinguishable from all other bovine papillomaviruses (BPVs) based on DNA sequence homology and antigenic properties and is thus characterised as a new entity, designated BPV-6. BPV-6 does not possess the interspecific papillomavirus antigen, its genomic DNA (7.2 kb) is smaller than, and does not show any sequence homology to BPV-1, BPV-2, or BPV-5, whereas it is approximately the same length as BPV-3 or BPV-4, with which it shares some sequence homology. The bovine papillomaviruses have been classified into two subgroups: subgroup A, composed of BPV-1, BPV-2, and BPV-5, all of which induce fibropapillomas, and subgroup B, composed of BPV-3, BPV-4, and BPV-6, all of which cause true epithelial papillomas.

Animals↗
PubMed1984

Alimentary fibropapilloma in cattle: a spontaneous tumor, nonpermissive for papillomavirus replication.

Fibropapillomatosis of the upper alimentary canal of cattle is described. The tumors, found in the esophagus, esophageal groove, and rumen, showed involvement of the subepithelial fibroblasts as well as of the squamous epithelial layer. Although the fibropapilloma cells harbored multiple episomal copies of the genome of bovine papillomavirus type 2 (BPV-2) easily detected by hybridization techniques, no mature virus could be isolated from these lesions or seen by electron microscopy, and no viral antigen could be detected by immunohistochemical methods. It would appear, therefore, that within the limitations of the techniques employed the alimentary canal epithelium and the underlying fibroblasts, while allowing BPV-2 DNA replication, are nonpermissive for the expression of the viral vegetative functions and that transformation of the epithelial cells, like transformation of fibroblasts, can take place in the absence of infectious viral progeny.

Animals↗
PubMed1983

Association of the human type C retrovirus with a subset of adult T-cell cancers.

To determine whether the human T-cell lymphoma-leukemia virus (HTLV) is associated with particular cancers, patient sera were surveyed for HTLV-specific antibodies. An association was seen with aggressive cancers of mature T-cells, specifically Japanese adult T-cell leukemia (ATL) and T-cell lymphosarcoma cell leukemia (TLCL), a similar cancer of Caribbean blacks. Ninety to 100% of these patients possessed HTLV-specific antibody. Forty-seven and 20% of relatives of ATL and TLCL patients, respectively, and 12 and 4% of healthy donors from ATL and TLCL endemic areas were also antibody positive. Visceral organ involvement, hypercalcemia, and skin manifestation, features of ATL and TLCL, were often seen in other antibody-positive patients. Childhood cancers, most cutaneous T-cell and all non-T-cell leukemias and lymphomas, myeloid leukemias, Hodgkin's disease, and solid tumors were not associated with HTLV. Healthy United States donors and European patients with non-malignant diseases were antibody negative. HTLV is thus associated with a subtype of adult T-cell leukemia-lymphoma, clustered in viral endemic areas, with apparent racial and geographic predilection.

Adult↗
PubMed1981

Control of parasitic bronchitis in calves: vaccination or treatment?

A 16-day infection of Dictyocaulus viviparus in two groups of calves was treated with levamisole and fenbendazole respectively. Five days afterwards the calves were reinfected with 4000 larvae and necropsied 21 days later. Although the lungworm burdens of the two groups of calves were reduced by about 70 per cent compared to a control group the clinical signs of dyspnoea, tachypnoea and coughing were indistinguishable from a primary infection. This was due to pulmonary emphysema, oedema and an acute epithelialising pneumonia apparently associated with the death and disintegration of lungworms in situ, the result of an incompletely developed immune response. The results are compared with those obtained with the lungworm vaccine. It was concluded that the outcome of any system of "control" which depends on drug therapy and reinfection is unpredictable and that vaccination offers the only effective method of prophylaxis.

Animals↗
PubMed1981

Unintegrated viral DNA sequences in a hamster tumor induced by bovine papilloma virus.

A fibrosarcoma was induced in a hamster by bovine papilloma virus type 2 (BPV2). The content of BPV2 DNA sequences was measured by DNA-DNA and cRNA-DNA hybridizations. The tumor contained approximately 300 BPV2 genome equivalents per cell. Southern blot hybridization indicated that the viral DNA was in free form, the entire genome most likely being present. In situ hybridization with BPV2 cRNA showed that multiple genome copies were present in each cell. Neither virus particles nor virus coat antigens could be detected in the tumor. A cell line was established from the fibrosarcoma, and the cells contained multiple copies of the BPV2 genome. The latter was in free form, and all of the DNA sequences appeared to be present in multiple copies and in all cells. An extensive search failed to reveal the presence of virus or viral antigens.

Animals↗
PubMed1978

Virus-induced papillomas of the alimentary tract of cattle.

An abattoir survey was carried out to determine the incidence and aetiology of squamous papillomas of the alimentary tract of cattle in Scotland and North England as they were suspected of being involved in the genesis of alimentary carcinoma in certain localized geographical areas. A total of 7,746 cattle of a wide age range was examined. Various subsets of this number were subjected to analyses of certain specific factors. The calculated overall incidence was 19% and the detailed site incidence and tumour multiplicity are given. The sites at which papillomas were found were identical with those at which carcinoma had been noted in animals from a high-cancer area. The number of sites affected by papilloma and the tumour multiplicity were much lower in the general population than in the high-cancer area. Inclusion bodies, identified by electronmicroscopy as virus, were found in tumour cell nuclei and a typical papilloma virus was purified from the tumours. The structure of the tumours is described and the possible plurality of bovine papilloma-viruses is discussed in the light of recent findings in the human viruses. The general interest of a naturally occurring and geographically localized oncogenic system, in which an environmental carcinogen and a virus might be involved, is extended.

Animals↗