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1.  Experimental sialodacryoadenitis virus infection in severe combined immunodeficient mice. 
Mice with a severe combined immunodeficiency in B and T lymphocytes and natural killer cells (SCID-beige) were inoculated intranasally with sialodacryoadenitis (SDA) virus, a coronavirus of rats. Animals were killed at designated intervals and tissues were examined for evidence of viral infection by light microscopy and immunofluorescence microscopy. Based on these criteria, there was no evidence that these immunodeficient mice were susceptible to infection with SDA virus.
PMCID: PMC1263420  PMID: 1653101
6.  LETTERS TO THE EDITOR 
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PMCID: PMC1696096  PMID: 17421773
7.  LETTERS TO THE EDITOR 
PMCID: PMC1695636  PMID: 17421690
8.  Fibrocartilaginous embolic myelopathy in a cat. 
The Canadian Veterinary Journal  1995;36(11):712-713.
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PMCID: PMC1687035  PMID: 8590429
9.  Coronavirus infections in the laboratory rat: degree of cross protection following immunization with a heterologous strain. 
One hundred and twenty-one specific pathogen-free male Wistar rats eight to ten weeks of age were used to evaluate the efficacy of Parker's rat coronavirus (PRC) in affording cross protection on subsequent challenge with virulent sialodacryoadenitis (SDA) virus. Sixty-two animals were inoculated intranasally on day 0 and 21 days later with approximately 10(2) median tissue culture infective doses (TCID50) of the tenth passage of PRC replicated in L-2 cells. Animals were selected at random postvaccination to evaluate the safety and efficacy of PRC by histopathology, immunohistochemistry and serology. At three and six months postvaccination (PV), vaccinated and seronegative control rats were inoculated intranasally with approximately 10(3) TCID50 doses of virulent SDA virus. Challenged rats were then killed at 6, 10 and 14 days postchallenge and necropsied. Evaluations were based on lesion indices in lacrimal and salivary glands and respiratory tract, the presence of viral antigen by immunohistochemistry, and antibody response. Lesions were observed in rats killed PV, but in general, they were significantly reduced compared with those present in seronegative animals post-exposure to virulent SDA virus (p < or = 0.05). However, they were still considered to be an unacceptable level for a routine vaccination procedure. Potvaccination antibody titers to rat coronavirus were evident in all animals tested at three or six months prior to challenge with SDA virus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMCID: PMC1263700  PMID: 7954126
10.  Preliminary characterization of the structural proteins of the coronaviruses, sialodacryoadenitis virus and Parker's rat coronavirus. 
A procedure was developed for the partial purification of the rat coronaviruses, sialodacryoadenitis virus (SDAV) and Parker's rat coronavirus (PRC). The SDAV and PRC were replicated in L-2 cell monolayer cultures, precipitated with ammonium sulphate, and further concentrated using sucrose density gradient centrifugation. The major SDAV and PRC proteins were identified by immunoblotting and compared with those of the JHM strain of mouse hepatitis virus (MHV-JHM). Monoclonal antibodies (MAb) against the M protein of JHM recognized proteins interpreted to be slightly smaller in immunoblots of SDAV and PRC (22.8 vs 23K for JHM). Similarly, a monoclonal antibody against the JHM N protein reacted with proteins of 53K in SDAV and PRC (vs 56 K for JHM). Polyclonal antisera to all three viruses also cross-reacted with the M and N proteins. Some cross-reactivity amongst the S proteins was observed. Based on these data, the structural proteins of the rat coronaviruses, SDAV and PRC are closely related to those of MHV-JHM.
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PMCID: PMC1263673  PMID: 8004548
11.  Experimental pneumonia in rabbits inoculated with strains of Pasteurella multocida. 
Domestic rabbits were inoculated with either a 3:A or 3:D serotype of Pasteurella multocida by aerosol, intravenous, or intratracheal inoculation. Different colony forming units of P. multocida were used. Animals which died or were killed after the 14 day observation period were examined macroscopically and microscopically for lesions in the lower respiratory tract. Pneumonic lesions were most consistently produced in rabbits inoculated intratracheally with serotype 3:A. Pulmonary and pleural lesions were observed in some animals inoculated intravenously with serotype 3:A. Lesions were minimal in rabbits inoculated with serotype 3:D. Of the three routes of inoculation evaluated, the intratracheal route appeared to be the best method to produce Pasteurella-associated lesions in the lower respiratory tract.
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PMCID: PMC1255156  PMID: 3742355
12.  Pasteurella multocida infection in the domestic rabbit: immunization with a streptomycin-dependent mutant. 
Fourteen Pasteurella multocida-free rabbits were inoculated intranasally with a streptomycin-dependent mutant of P. multocida serotype 12:A. Vaccinations with approximately 10(8) colony forming units were done on days 0, 14 and 28. Two weeks later the animals were separated into groups, which included 12 rabbits divided into two control groups of six unvaccinated Pasteurella-free animals. Seven vaccinated rabbits were challenged intranasally with the homologous virulent parent strain and the other seven vaccinates were challenged with a virulent strain of serotype 3:A. Rabbits were necropsied two weeks later. The vaccinated group challenged with the parent strain showed a more rapid nasal clearance of the organism than the vaccinated group challenged with the heterologous strain. However, the number of positive cultures of P. multocida recovered from tissues post-challenge were similar in vaccinated and control animals. In a significant number of animals, vaccination with serotype 12:A induced detectable antibody production to somatic antigens of both 12:A and heterologous strain 3:A.
PMCID: PMC1236154  PMID: 4016588
14.  Characterization of Pasteurella multocida isolated from rabbits in Canada. 
In a survey for the somatic and capsular serotypes of Pasteurella multocida present in domestic rabbits in Canada, but mainly in Ontario, samples were obtained from research facilities, commercial rabbitries and from abattoir and necropsy specimens. Sources of isolates were upper respiratory tract infections, localized bronchopneumonias , acute fibrinous pneumonias, abscesses and otitis media. Of 59 isolates obtained, 47.0% were type 12:A, 30.5% 3:D and 12.0% were 3:A. Less common types were 12(4):A, 12:D, 4(12):A and 3:untypable. Somatic group 3 was most commonly isolated from acute pneumonic disease, while serogroup 12:A was most commonly found in upper respiratory tract infections and in localized chronic bronchopneumonia. Two serotypes of P. multocida were isolated from four pneumonic lungs collected from abattoir specimens. Most isolates were susceptible to the commonly used antibiotics.
PMCID: PMC1236030  PMID: 6722644
15.  Experimental Brucella canis Infection in the Monkey (Macaca arctoides) 
Four stumptail Macaque monkeys (Macaca arctoides) were each inoculated with approximately 1010 organisms from a culture of Brucella canis. Two animals were inoculated via the oral and conjunctival route and the other two monkeys were inoculated intravenously with the organisms. A fifth animal served as a control. Blood samples were taken at weekly intervals for hematological, serological and bacterialogical studies. The monkeys were killed at five and ten weeks post-inoculation and tissues taken from a variety of organs for bacterial culture. B. canis was isolated from the peripheral blood of inoculated monkeys for up to seven weeks post inoculation and all infected monkeys developed significant neutralizing antibody titers to the organism. The bacterium was isolated from some tissues, including the uterus of one monkey, in the two animals killed at five weeks post-inoculation. Focal granulomatous lesions were sometimes observed in the liver, spleen and lymphoid tissue of inoculated monkeys. Such lesions are similar to those described in other brucella infections. Human infections with B. canis have occurred and the possible dangers entailed in exposure to the organism should again be emphasized.
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PMCID: PMC1319672  PMID: 4261836
16.  The Histopathological Changes in the Skin of Pigs With Dermatosis Vegetans 
Dermatosis vegetans, an hereditary disease seen in Landrace swine, is characterized by defects in the skin, and a giant cell pneumonia. Histological changes of the skin from 12 affected pigs of various ages were described. Lesions of the skin were characterized by acanthosis, hyperkeratosis, parakeratosis, and leukocytic infiltration. In general, the defects followed a definite developmental pattern, which were divided into three stages: (1) the stage of early development, (2) the intermediate stage characterized by an acute inflammatory response, and (3) the stage of regression. The specific role of the eosinophil, a prominent feature in this and other diseases of the porcine skin, remains obscure.
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PMCID: PMC1319322  PMID: 4237296
18.  Effect of time of exposure to rat coronavirus and Mycoplasma pulmonis on respiratory tract lesions in the Wistar rat. 
The effects of time of exposure on the progression of pulmonary lesions in rats inoculated with Mycoplasma pulmonis and the rat coronavirus, sialodacryoadenitis virus (SDAV) were studied, using six groups of 18 SPF Wistar rats (n = 108). Rats were inoculated intranasally as follows: Group 1, sterile medium only; Group 2, sterile medium followed one week later by 150 TCID50 SDAV; Group 3, sterile medium followed by 10(5.7) colony forming units of M. pulmonis; Group 4, SDAV followed one week later by M. pulmonis; Group 5, M. pulmonis followed one week later by SDAV; Group 6, M. pulmonis followed two weeks later by SDAV. Six rats from each group were euthanized at one, two and three weeks after the final inoculation. In a separate experiment, six additional animals were inoculated in each of groups 3, 5 and 6 (n = 18) and were sampled at five weeks after they had received M. pulmonis. Bronchoalveolar lavage and quantitative lung mycoplasma cultures were conducted on two-thirds of the rats. Histopathological examination and scoring of lesion severity were performed on all animals. Based on the prevalence and extent of histopathological lesions, bronchoalveolar lavage cell numbers, neutrophil differential cell counts and the isolation of M. pulmonis, the most severe disease occurred in the groups that received both agents. There was no significant difference in lesion severity between the groups receiving both agents other than in those examined during the acute stages of SDAV infection. Based on these results, it is evident that SDAV enhances lower respiratory tract disease in Wistar rats whether exposure occurs at one week prior to or at various intervals following M. pulmonis infections.
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PMCID: PMC1263735  PMID: 7704844
19.  Coronavirus infection in the laboratory rat: immunization trials using attenuated virus replicated in L-2 cells. 
Sixty-nine specific pathogen-free male Wistar rats approximately eight weeks of age were used to evaluate the efficacy of an attentuated strain of sialodacryoadenitis (SDA) virus in providing protection against infection on subsequent challenge with virulent SDA virus. Fifty-four animals were inoculated intranasally with approximately 10(3.5) median cell culture infectious doses of the 25th passage of SDA virus in L-2 cells. Randomly-selected vaccinated animals were killed in order to evaluate the safety and efficacy of attenuated virus by histopathological examination of the salivary glands, lacrimal glands, and lower respiratory tract, and titration of sera for antibody to SDA virus. At three months and six months postvaccination (pv), animals were selected at random and challenged with virulent SDA virus. Seronegative, age-matched animals were also challenged, and served as controls. In animals examined at six to ten days pv, lesions were absent in submandibular and parotid salivary glands and lacrimal glands, but transient lesions were present in major airways of the lower respiratory tract. In a comparison of the incidence and extent of lesions, and antibody titers in challenged vaccinates and seronegative controls, lesions were minimal or absent in vaccinates compared to challenged naive rats, particularly in animals inoculated at three months pv. In addition, antibody titers in challenged vaccinates were much higher than were postinoculation titers in inoculated controls. In a comparison of lesions in salivary and lacrimal glands in vaccinated and control animals challenged at six months pv, there was a significant reduction in the number of animals without lesions in the vaccinated group (p = less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMCID: PMC1263415  PMID: 1653100
20.  Experimental sialodacryoadenitis virus infection in athymic CD-1 mice. 
The purpose of the study was to investigate the susceptibility of nude mice to sialodacryoadenitis virus. Young adult male CD-1 nude mice were inoculated intranasally with virus, killed at 2, 4, 6, 8, 10 and 20 days postinoculation and examined for virus-induced lesions in tissues including respiratory tract. Inoculated and control mice were examined by virus isolation and serology. In a companion study, male Wistar rats were inoculated intranasally with the same inoculum, and examined by histopathology, immunofluorescence microscopy and serology. In virus-inoculated mice, lesions were minimal in the lower respiratory tract, and were absent in other tissues. Virus was isolated from the lower respiratory tract in animals sampled at six or eight days postinoculation. Antiviral antibody was not detected in sera from inoculated and control mice. Virus-associated lesions and antibodies were readily detected in rats following inoculation. Based on this study, there is no evidence that inadvertent exposure to sialodacryoadenitis virus should pose a threat to CD-1 nude mice, and their susceptibility to the disease appears to be similar to that reported in euthymic CD-1 mice.
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PMCID: PMC1255465  PMID: 2844379
21.  Pharmacokinetics of tetracycline in the domestic rabbit following intravenous or oral administration. 
Tetracycline hydrochloride was administered to domestic rabbits using a single bolus by the intravenous and oral routes. Pharmacokinetic parameters were determined for intravenous (10 mg/kg) and oral (150 mg/kg) administration. The effect of fasting for 12 h on the drug elimination kinetics after oral administration was evaluated. Tetracycline was added to the drinking water at 800 mg/L or 1600 mg/L. Drug and water intake and serum levels were monitored. Mean serum pharmacokinetic parameters following intravenous administration were; 0 intercept beta curve B (microgram/mL) = 7.5, rate of elimination from body -b (min-1) = 0.0058, half life elimination from body -t 1/2 b (min) = 120.0, wt(kg) = 3.2 determined using combined male and female data. Mean serum pharmacokinetic parameters after oral administration (single bolus) were -B (microgram/mL) = 1.54 (full stomach) and 2.71 (empty stomach), b(min-1) = 0.0037 (full stomach) and 0.0035 (empty stomach), t 1/2 b (min) = 190.3 (full stomach) and 216.2 (empty stomach). Administration of tetracycline in the drinking water produced very low to nondetectable levels of drug in the serum, even at high dosage, and the 1600 mg/L drug concentration was accompanied by a significant drop in water intake. Thus, it is evident that concentrations of tetracycline of up to 1600 mg/L drinking water will not produce levels of antibiotic consistently detectable in the serum.
PMCID: PMC1255391  PMID: 3349401

Results 1-21 (21)