Close supermassive binary black holes.

It has been proposed that when the peaks of the broad emission lines in active galactic nuclei (AGNs) are significantly blueshifted or redshifted from the systemic velocity of the host galaxy, this could be a consequence of orbital motion of a supermassive black-hole binary (SMBB). The AGN J1536+0441 ( = SDSS J153636.22+044127.0) has recently been proposed as an example of this phenomenon. It is proposed here instead that J1536+0441 is an example of line emission from a disk. If this is correct, the lack of clear optical spectral evidence for close SMBBs is significant, and argues either that the merging of close SMBBs is much faster than has generally been hitherto thought, or if the approach is slow, that when the separation of the binary is comparable to the size of the torus and broad-line region, the feeding of the black holes is disrupted.

Effect of primary-stage feline immunodeficiency virus infection on subsequent feline calicivirus vaccination and challenge in cats.

The effect of experimental primary-stage feline immunodeficiency virus (FIV) infection on feline calicivirus (FCV) vaccination and challenge in cats was studied. Clinical signs of acute FCV disease were more widespread in the cats which were infected with FIV than in those which were not. FIV infection also prolonged shedding of FCV, with more of the FIV-infected cats becoming chronic carriers. Although vaccination induced protection against acute FCV disease, this was to a lesser degree in FIV-infected cats. Vaccination by itself also appeared to enhance long-term virus shedding. There was evidence of an impaired anamnestic FCV-neutralizing antibody response in FIV-infected cats following FCV challenge.

Studies on the survival of canine coronavirus under different environmental conditions.

Canine coronavirus (CCV) is a common faecal agent which is difficult to isolate. This study shows CCV to survive well at temperatures below -20 degrees C but not at temperatures above 4 degrees C. The presence of faecal material markedly reduced CCV survival times at temperatures ranging from 20 degrees C to -70 degrees C. Thus, it is suggested that diagnostic faecal material should be diluted 1:10 (w/v) with growth medium and examined at the earliest opportunity.

Studies on the role of feline calicivirus in chronic stomatitis in cats.

Two groups of cats were inoculated oro-nasally with one of two isolates of feline calicivirus (FCV) from clinical cases of chronic stomatitis. All cats developed signs typical of acute FCV infection; namely, ocular and nasal discharge, conjunctivitis, and marked oral ulceration. None of the cats shed virus beyond 28 days. Seronegative control cats were then infected with a lower dose of one isolate, but again only acute signs were seen and no carriers produced. The original cats were then re-infected with the heterologous isolate. As before, only signs of acute disease were seen, but the range of clinical signs and severity was reduced. Virus shedding patterns in one group were similar to those seen originally, but in the other the duration was reduced. No chronic stomatitis developed over the 10 months of the study. Serum virus neutralising and serum and salivary class specific immunoglobulin responses were investigated. Although long-term carriers were not induced, no relationship between cessation of virus shedding in an individual animal and systemic and local antibody responses was seen.

Virus shedding and immune responses in cats inoculated with cell culture-adapted feline infectious peritonitis virus.

Eight specific pathogen-free cats were inoculated orally or parenterally with a cell culture-adapted strain of feline infectious peritonitis virus (FIPV). Faeces and oropharyngeal swabs were monitored daily for infectious virus by inoculation of feline embryo lung cells. Virus was recovered from both sites for approximately 2 weeks after inoculation, before clinical signs of disease developed. Peripheral blood lymphocytes collected from these cats were tested in an in-vitro blastogenic assay using concanavalin A (con A) and FIPV antigen. All cats showed a profound suppression of the response to con A which only recovered to pre-inoculation levels in 2 cats, one of which survived. These 2 cats also responded to FIPV antigen on the 21st day after infection, the greater response being in the survivor. The other cats, surviving 16-18 days, developed no response to FIPV antigen. Antibody titres, measured by immunofluorescence and by virus neutralization, rose rapidly to very high levels in all cats, regardless of the route of inoculation.

Studies on natural transmission of Bordetella bronchiseptica in cats.

Two pregnant specific-pathogen-free (SPF) cats, from a colony endemically infected with Bordetella bronchiseptica, were housed under barrier conditions in the latter stages of pregnancy in order to study the possible transmission of the organism to their kittens. Both queens had antibody titres to Bordetella bronchiseptica of 1 in 320 at the start of the experiment but did not shed Bordetella bronchiseptica until 9 days and 6 weeks after parturition, respectively. Five of the nine kittens had detectable maternally-derived-antibody to Bordetella bronchiseptica which declined to < or = 1 in 40 by two weeks of age. Kittens were weaned at 12 weeks of age. No Bordetella bronchiseptica was isolated from any of the kittens and none seroconverted over this time. At 15 1/2 weeks of age, half of each litter were housed separately and inoculated intra-nasally with 10(8) colony-forming-units B. bronchiseptica. Mild signs of upper respiratory tract disease were seen and the organism was isolated for 19 weeks following inoculation when the experiment ended. Seroconversion occurred at 4 weeks postinoculation. Oral treatment of two clinically-recovered kittens with doxycycline once a day did not eliminate shedding.

Systemic and pulmonary immune response to intrabronchial administration of ovalbumin in calves.

Local immunization of the respiratory tract may be the best way to achieve protection against respiratory pathogens. In order to do so successfully, it is important to fully understand how the immune response to antigen administered via the respiratory route develops. We studied the respiratory and systemic immune response after subcutaneous (SC) and intrabronchial (IB) inoculation of calves with ovalbumin (OVA). Eight calves received two SC inoculations of OVA and eight other calves received two SC and three additional IB inoculations of OVA. The occurrence of OVA-specific antibodies and antibody-secreting cells (ASC) was measured over time using isotype-specific enzyme linked immunosorbent assay (ELISA) and ELISPOT. SC immunization of calves did not result in OVA-specific IgA in bronchoalveolar lavage (BAL) fluid. Subcutaneous priming followed by intrabronchial challenge caused an initial IgG1 response in the bronchoalveolar lavage fluid, followed by a large IgA response. The presence of IgG1-ASCs indicated that the IgG1 was at least partially locally produced. Most of the OVA-specific IgA in the BAL fluid was secreted by pulmonary ASCs as indicated by the large number of IgA-ASCs in BAL samples and the low serum level of OVA-specific IgA. Antigen-specific IgG1 ASCs were detectable among peripheral mononuclear cells after culture with OVA.

Myopathy with core-like structures in a dog.

Core-like structures were seen histologically in many of the fibres of the triceps and biceps femoris muscles of an 18-months-old male Great Dane with muscle weakness and moderate proximal muscular atrophy. The structures were lightly staining and lacked cross-striations. Some contained vacuoles and nuclei. Scattered necrotic and presumably regenerating fibres were also present. Ultrastructurally, the cores contained disarrayed filament bundles attached to thickened Z-lines which were compatible with the rods of rod myopathies. The condition was not fully characterized, but has certain similarities to a group of rare human congenital muscular disorders which includes central core disease.

Thyroid pathology in canine hypothyroidism.

Biopsy or post mortem specimens from the thyroid glands of 7 dogs with clinical hypothyroidism were examined histologically. Six of the 7 cases were diagnosed histologically as lymphocytic thyroiditis which is characterized by widespread destruction and replacement of the gland by an infiltrate of lymphocytes, plasma cells and macrophages. The 7th case was characterized by fibrosis, with minimal inflammatory cell infiltration and might represent an end stage of lymphocytic thyroiditis. Five of the 7 dogs were female and 4 of these animals had shown clinical signs since 2 years of age. Comparisons are made with a previous report of functional lymphocytic thyroiditis in the pet dog and with similar conditions in man and an obese strain of White Leghorn poultry.

Canine coronavirus infection in the dog following oronasal inoculation.

The pathogenesis of canine coronavirus (CCV) infection in 10-week-old puppies was studied up to 14 days after oronasal inoculation. Mild diarrhoea was seen from three to 11 days after inoculation, approximately coincident with faecal virus shedding. Virus was initially isolated from the tonsils on day 3, and then from both small and large intestinal tissues up to 14 days after inoculation. Virus was also isolated from liver and lung. Histological changes were not seen in any tissues, but CCV antigen was detected, using a peroxidase antiperoxidase staining technique, mainly in epithelium overlying gut-associated lymphoid tissue. Virus neutralising antibody was first detected on day 10. Specific anti-CCV IgM was first detected in plasma three days after inoculation and IgG on days 4 to 7. Small amounts of anti-CCV IgG, IgM and IgA were detected in duodenal secretion, but none in bile.

Antibody and complement mediated lysis of felid herpesvirus 1 infected cells in vitro.

The lysis of cells infected by felid herpesvirus 1 (FHV) by feline anti-FHV antibody and complement was demonstrated. Lytic activity was sensitive to dilution of both antibody and, especially, complement. It was first detected within 10 to 20 minutes, increased rapidly during the next 30 minutes of incubation and then rose more slowly in a linear manner. Using standard antibody and complement concentrations and assay duration, it was shown that FHV infected cells underwent significant (P less than 0.05) lysis from eight hours after infection in a system in which FHV-specific membrane antigen was first detected at three hours after infection and spread of FHV by the intracellular route began eight to nine hours after infection. The ability of antibody and complement to reduce FHV spread in this system was demonstrated by a significant (P less than 0.05) reduction in FHV plaque numbers, although the restriction of spread was not absolute. Chelation of divalent cations and heat inactivation of complement factor B revealed that the lytic system was dependent on factor B and Mg2+ but not Ca2+, suggesting involvement of the alternative pathway of complement activation.

Efficacy of an inactivated feline calicivirus (FCV) vaccine against challenge with United Kingdom field strains and its interaction with the FCV carrier state.

The efficacy of an inactivated vaccine derived from feline calicivirus (FCV) strain FS2 was assessed against challenge with three UK field strains of FCV. The mean clinical score, calculated on the number of signs recorded per day over 21 days after challenge, was lower for vaccinated cats when compared to unvaccinated animals though the difference was not statistically significant. All cats excreted FCV throughout the three weeks following challenge and there was no difference in the number of days of virus shedding during this period between vaccinated and unvaccinated animals. The development of FCV serum neutralising antibody titres following vaccination and challenge was recorded. In the second part of the study the ability of vaccinated and challenged cats to become FCV carriers and then infect susceptible in-contact animals was demonstrated.

Responses of cats to nasal vaccination with a live, modified feline herpesvirus type 1.

Intranasal vaccination with a cold-adapted strain of feline herpesvirus type 1 (FHV-1) two days before challenge gave partial protection, and four days before challenge gave complete protection, against feline viral rhinotracheitis. Protection at this time appeared to be specific since vaccination with FHV-1 did not affect the disease caused by the unrelated feline calicivirus. The time course of onset of protection also confirmed that the protective mechanism was likely to be specific. However, six days after vaccination only low levels of FHV-specific IgA and IgM antibody and of interferon were found in serum and nasal washings. In lymphocyte transformation assays neither peripheral blood lymphocytes nor tonsil lymphocytes gave a significant proliferative response in the presence of FHV antigen. Pathogenesis experiments demonstrated that the tonsil and nasal turbinates were the most important sites of virulent FHV-1 replication. Vaccination significantly reduced levels of infectious virus found in both sites. The results provide evidence that no one mechanism is responsible for protection following vaccination but local specific responses are more likely to be involved.

A study of feline upper respiratory tract disease with reference to prevalence and risk factors for infection with feline calicivirus and feline herpesvirus.

A cross-sectional survey of a convenience sample of cats was carried out to determine the prevalence of and risk factors for respiratory tract disease, feline calicivirus (FCV) infection and feline herpesvirus (FHV) infection. Seven hundred and forty cats were studied; samples for isolation of FCV and FHV were obtained from 622 (84%). Data on individual cat and household variables were obtained by questionnaire for each cat and analysed using univariable and logistic regression analysis. Thirty-eight percent (282/740) of cats surveyed had respiratory tract disease. Eighteen of 24 predictor variables were found to be significantly (P<0.05) associated with the presence of respiratory tract disease in a cat on univariable analysis. Following logistic regression, several factors retained significance including isolation of FCV and FHV, younger cats (4-11 months of age) and multiple cat households. A negative association was found with breeding catteries and other types of household in comparison with rescue catteries. Overall, feline calicivirus was isolated from 162/622 (26%) of cats sampled; 33% of the cats with respiratory tract disease were FCV positive compared to 21% of healthy cats. Variables significantly associated with FCV isolation on logistic regression were the presence of respiratory tract disease and contact with dogs with and without respiratory tract disease. Feline herpesvirus was isolated from 30/622 (5%) of all cats sampled; 11% of cats with respiratory tract disease were FHV positive compared to 1% of healthy cats. Variables significantly associated with FHV isolation on univariable analysis included age, gender, and the presence of respiratory tract disease. Vaccination showed a negative association. Logistic regression analysis of the data for FHV was limited by the sample size and the low prevalence of FHV.

Induction and enhancement of feline infectious peritonitis by canine coronavirus.

Preexisting antibody to feline infectious peritonitis virus (FIPV) causes acceleration and enhancement of disease on subsequent infection of cats with FIPV. Other workers have shown that canine coronavirus (CCV) can infect cats subclinically, but have found no evidence of enhancement of, or protection against, subsequent FIPV infection. With various isolates of CCV, we determined that 1 strain of CCV can induce transient mild diarrhea in cats and, furthermore, that previous infection with CCV causes acceleration and enhancement of subsequent infection with FIPV. In addition, sequential inoculation of cats with another strain of CCV caused lesions indistinguishable from those of FIP, without exposure at any time to FIPV.

Non-neoplastic memmary hypertrophy in the cat associated either with pregnancy or with oral progestagen therapy.

Nine cases of mammary glandular hypertrophy in the cat are described. Three cases occurred in pregnant queens aged between six and eight months and one in an aged non-pregnant queen. The other cases were in neutered animals which had been treated with megestrol acetate for periods of between 14 months and five years. The pregnant queens were spayed and their mammae returned to normal; in the other cats the affected mammary glands were removed surgically. No recurrence occurred in seven cats in which adequate follow-up information was available. The importance of differentiating this benign lesion from mammary neoplasia is discussed.

PIP: This report is based on data from 9 cats: 4 were queens, of which 3 were pregnant, 5 were neutered cats, 2 male and 3 female, which had been receiving megestrol acetate (MA) for the treatment of miliary eczema for periods of 14 months to 5 years. In all cats the condition was painless. There was gross enlargement of the mammary glands. In 2 cases the skin over the glands was ulecerated. Ovaro-hysterectomy was done on the 3 pregnant queens. The other 6 cases were diagnosed from biopsy specimens. The lesions were then excised. Following ovaro-hysterectomy, the lesions softened and gradually regressed. In the neutered cats no recurrence occurred during the follow-up period. Histological studies showed only benign changes with fibroglandular hyperactivity. An excess of progesterone has been suggested as a cause. The MA therapy cannot be excluded as a cause in some cases. Differentiation of this condition from adenocarcinoma is important. The distinction may be made by histological study of biopsy specimens.

Interaction of an intranasal combined feline viral rhinotracheitis, feline calicivirus vaccine and the FVR carrier state.

Eight cats were vaccinated intranasally with a combined feline calicivirus/feline viral rhinotracheitis (FVR) virus commercial vaccine. Following intranasal challenge with a field strain of FVR virus and subsequent treatment with corticosteroid, no virus was recovered from any of the eight cats, while FVR virus was recovered following corticosteroid treatment from two of four unvaccinated and challenged controls. No evidence was found for the development of an FVR virus carrier state with the intranasal vaccine virus.

Clinical and radiological features of anterior mediastinal lymphosarcoma in the cat: a reveiw of 30 cases.

The clinical and radiological features of 30 cases of anterior mediastinal lymphosarcoma in the cat are described; they represented 48 per cent of all cases of lymphosarcoma recorded at the University of Bristol Veterinary School between 1972 and 1977. The condition principally affected young cats and there was a predisposition in oriental breeds. Dyspnoea and regurgitation were the two most common major presenting signs. Diagnosis was made in most cases on the basis of radiological examination, but in some cytological examination of the thoracic fluid was necessary for confirmation.

Appraisal of teachers in the Faculty of Veterinary Science, University of Liverpool.

In 1988, the Faculty of Veterinary Science, University of Liverpool, introduced a system of teacher appraisal, following the report of a faculty working party. The system is designed to provide information which will help the personal development of teaching skills, and also to provide the information required by the university for promoting a lecturer to senior lecturer. It incorporates opinions from students, collected formally by means of questionnaires, and from personal peers chosen by the lecturer, and a self-appraisal record which forms the basis of an annual review from the head of department. Official peers, drawn from both the veterinary faculty and the department of education and extension studies, are trained and used in pairs, to assess and report on staff eligible for promotion. The system has been evaluated by a research assistant funded by the University Funding Council.

Interaction of a combined feline viral rhinotracheitis-feline calicivirus vaccine and the FVR carrier state.

The effect of field feline viral rhinotracheitis (FVR) virus challenge on cats previously vaccinated with a combined FVR/feline calicivirus intramuscular vaccine was studied in relation to the development of an FVR carrier state. There was no virus shedding of either of the two vaccine viruses following vaccination. Treatment with corticosteroid 60 days after vaccination and before challenge with FVR virus did not induce virus re-excretion in vaccinates or controls; neither did similar treatment induce shedding 63 days after challenge of both vaccinates and controls with virulent field virus. After a further 55 days however, FVR virus shedding was elicited in one of four previously vaccinated and challenged cats compared with two of four unvaccinated and challenged controls. Two sentinel cats remained virologically and serologically free of FVR throughout. The vaccine was shown to be effective in controlling the disease; 12 weeks after initial vaccination no clinical signs were seen in three of four cats following intranasal challenge with 10(5)CCID50 of virulent field FVR virus, and a mild transient unilateral ocular and nasal discharge was seen in the remaining cat for one day only. Severe clinical signs of approximately 10 days' duration were seen in all four unvaccinated challenged controls. The virological and serological responses of the cats were also recorded.