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Biomedical subjects

F W Scott

Publications and source records attributed to F W Scott.

At least 109 records · Page 6Linked to original sources
PubMed1980

Virucidal disinfectants and feline viruses.

Thirty-five commonly used commercial disinfectants (disinfectants, antiseptics, sanitizers, and detergents) were evaluated for their virucidal activity against three feline viruses; feline viral rhinotracheitis virus (a herpesvirus), feline calicivirus, and feline panleukopenia virus (a parvovirus). Disinfectants were diluted as recommended by the manufacturer and were reacted with virus for 10 minutes at room temperature. Viruses were separated from disinfectants by gel filtration in special centrifuge tubes, and were assayed for infectivity in feline cell cultures. All 22 products tested were virucidal for feline viral rhinotracheitis virus, 11 of 35 were virucidal for feline calicivirus, but only 3 of 27 tested were effective against feline panleukopenia virus. A 0.175% sodium hypochlorite solution was the most effective and practical broad-spectrum virucidal product used alone or in combination with other disinfectants/detergents.

Animals↗
PubMed1980

Disseminated intravascular coagulation in experimentally induced feline infectious peritonitis.

Disseminated intravascular coagulation was induced in kittens by intraperitoneal inoculation of feline infectious peritonitis virus (FIPV). Kittens seronegative to FIPV survived significantly (P less than 0.05) longer than those seropositive to FIPV. Pyrexia, anemia, icterus, hyperbilirubinemia, and elevated concentrations of liver-specific enzymes were detected in the inoculated cats. Lesions induced included disseminated fibrinonecrotic and pyogranulomatous inflammation, hepatic necrosis, and widespread phlebitis and thrombosis. Localization of FIP viral antigen and immunoglobulin G was demonstrated in foci of heptic necrosis by immunofluorescence miroscopy. Lymphopenia, thrombocytopenia, hyperfibrinogenemia, and increased quantities of fibrin-fibrinogen degradation products were present in cats after the onset of clinical illness. Depression of factor VII, VIII, IX, X, XI, and XII plasma activities and prolongation of prothrombin and partial thromboplastin times also developed in infected cats. The accelerated onset of clinical disease and mortality in seropositive kittens vs seronegative kittens and the association of virus and antibody in multiple foci of hepatic necrosis suggest an immune-mediated component is involved in the pathogenesis of this disease.

Animals↗
PubMed1980

Immunofluorescent and electron microscopic studies of feline small intestinal organ cultures infected with feline infectious peritonitis virus.

The pathogenesis, morphology, and morphogenesis of feline infectious peritonitis virus were studied in feline small intestinal organ cultures. Characteristic coronaviruses were demonstrated by electron microscopy in the extracellular organ culture fluid taken at 1 through 12, 15, 22, 31, and 43 days after the cultures were inoculated. Viral particles had a mean diameter of 94 nm. Numerous petal-shaped projections approximately 15 nm long were seen on the envelopes. Specific immunofluorescence was detected in the absorptive epithelial cells of villi of small intestinal organ cultures at 1 through 12 days after they were inoculated. By electron microscopy, coronavirus particles were observed entirely in the cytoplasm of the infected columnar epithelial cells of villi with no apparent nuclear involvement. Thin sections of the villous epithelium of small intestinal organ cultures showed a number of ultrastructural alterations, and morphogenesis of feline infectious peritonitis virus in the absorptive epithelial cells of villi was consistent with that for other known human animal coronaviruses.

Animals↗
PubMed1979

FIP antibody test--interpretation and recommendations.

It is my opinion that the feline infectious peritonitis (FIP) antibody test currently is being over-used and over-interpreted. The test is of value to the practitioner in specific circumstances, but by itself it is not diagnostic of clinical FIP. Further, it is my opinion that clinically healthy FIP antibody-positive cats should not be euthanatized under a routine test and eradication policy.

Animals↗
PubMed1979

Isolation and immunisation studies of a canine parco-like virus from dogs with haemorrhagic enteritis.

A newly recognised canine parvo like virus was isolated from faeces of dogs with haemorrhagic enteritis. Cell cultures from several species were susceptible to it. Virus infected cells could be demonstrated by staining with fluorescent antibody reagents (prepared against canine virus or feline panleucopenia virus) or by haemagglutination with pig or rhesus monkey red blood cells. Inhibition of haemagglutination by specific antiserum prepared in specific-pathogen-free beagles provided a convenient method for viral identification. Experimental inoculation of specific-pathogen-free beagles resulted in elevated body temperatures and caused lymphopenia lasting one to three days. Feline panleucopenia virus vaccines protected dogs against challenge with virulent canine parvo-like virus.

Animals↗
PubMed1979

Prevalence of neutralizing antibody to the calf rotavirus in New York cattle.

In March 1973, a modified live virus vaccine was released for sale in the United States for the protection of neonatal calves from infection with calf rotavirus. At that time no published evidence existed that this agent was present in New York or the New England states. Serum neutralizing antibodies for the calf rotavirus (reovirus-like agent of neonatal calf diarrhea) were detected in serum from 108 of 110 dairy cattle in New York State representing 78 different herds. To exclude the possibility that the demonstrated serologic response may have been stimulated by vaccine virus, 36 samples were included that had been collected prior to the date of vaccine release. Neutralizing antibodies were demonstrated in 108 of the 110 sera ranging from titers of 4 to greater than 1024, thereby offering indirect evidence of the ubiquitous nature of calf rotavirus in New York.

Animals↗
PubMed1979

Bovine fetal inoculations with calf rotavirus.

The serological and histopathological responses of bovine fetuses to in utero inoculation with virulent and attenuated strains of the calf rotavirus (reovirus-like agent of neonatal calf diarrhea) are described. Thirteen bovine fetuses, 63 to 190 days of gestation, were inoculated in utero with attenuated (three fetuses) or field strain virus (nine fetuses) or both (one fetus).Serum-neutralizing antibody titers ranging from 1:16 to > 1:256 were detected in six of eight fetuses tested, demonstrating the ability of the bovine fetus to respond immunologically to this agent. The youngest fetus in the series was inoculated at 63 days of gestation and developed a titer of 128 in 64 days. This represents the earliest stage of gestation at which a bovine fetus has been inoculated with a bovine virus and found to produce antibody to it. Serum neutralizing titers in six of the eight dams tested increased significantly following the inoculations of their fetuses in utero. Histological changes associated with viral replication and antigenic stimulation of the lymphoreticular system were observed. Pneumonic lesions consisting of both local and diffuse lymphoreticular proliferation were present in five of the nine fetuses that were alive at slaughter. Gliosis and perivascular cuffing were noted in the brains of two of these fetuses and meningitis was seen in one. No evidence of teratogenic change was found.

Animals↗
PubMed1978

The rate of deoxyribonucleic acid synthesis by cultured Chinese-hamster ovary cells. An application of isotope-dilution analysis.

The rate of DNA synthesis is exponentially growing cells was determined by isotopedilution analysis of the incorporation of [me-3H]thymidine. Thymidine concentrations greater than 7 micrometer were used so that the rate-limiting step governing incorporation would be at the level of DNA polymerase rather than at the level of thymidine kinase [Sjostrom & Forsdyke (1974) Biochem. J. 138, 253-262]. In early exponential phase the rate determined by isotope-dilution analysis closely correlated with the rates calculated either from growth curves or from known cell-cycle parameters. However, in late-exponential phase the rate calculated from the growth curve was less than that determined by isotope-dilution analysis. We conclude that, under certain conditions, the pool-corrected rate of incorporation of [me-3H]thymidine, as determined by isotope-dilution analysis, can accurately reflect the rate of DNA synthesis. Discrepancies between the observed rate of DNA synthesis and increase in cell number could reflect an exponential degeneration of post-S-phase cells.

Cell Division↗
PubMed1978

Feline panleukopenia. III. Development of lesions in the lymphoid tissues.

Germfree and specific pathogen-free cats were inoculated with feline panleukopenia virus. Cats were necropsied 2 to 6 days after inoculation and tissues from the thymus, lymph nodes and spleen taken for histological and immunofluorescence studies. Necrosis of lymphoid cells in the thymic cortex began 3 days after inoculation and continued for 5 to 6 days after inoculation when the thymus was nearly depleted of lymphocytes. Immunofluorescence studies showed the lesions to be caused by virus. There was gross and histological involution of the thymus in both germfree and specific pathogen-free cats. The lymph nodes and spleen of uninoculated germfree cats looked "inactive" and lacked well developed lymphoid follicles and paracortical areas. In both germfree and specific pathogen-free cats there was necrosis in both follicular and paracortical areas of the lymph nodes and follicular and periarteriolar areas of the spleen 3 to 4 days after inoculation. Immunofluorescence showed these areas had virus infection. By 5 to 6 days after inoculation, these areas were populated by many lymphoblastoic cells. Even though significant destruction of lymphoid cells occurred, subsequently, in cats that develop mild clinical illness, these lymphoid tissues seemed stimulated rather than depleted of lymphocytes.

Animals↗
PubMed1978

An immunofluorescence diagnostic test for feline viral rhinotracheitis.

Hyperimmune serum against feline viral rhinotracheitis was produced in a goat and conjugated with a fluorescent dye. Cell cultures infected with rhinotracheitis virus had positive immunofluorescence. Cell cultures infected with other feline viruses and herpesviruses of other species did not fluoresce. In cats experimentally infected with rhinotracheitis virus, the virus was isolated from nasal and conjunctival swabs 1 to 9 days after inoculation. Nasal smears stained with the conjugated antiserum fluoresced 1 to 9 days after inoculation when clinical disease was most apparent. Conjunctival smears had positive immunofluorescence 1 to 6 days, but not 9 days, after inoculation. On postinoculation day 23, rhinotracheitis virus was not isolated from nasal or conjunctival swabs and nasal and conjunctival smears did not fluoresce. Rhinotracheitis virus or feline calicivirus was isolated from naturally infected cats with upper respiratory tract disease. Nasal and conjunctival smears from rhinotracheitis virus-infected cats had positive immunofluorescence in all cast showing clinical illness. Smears from 1 clinically normal cat from which rhinotracheitis virus was isolated did not fluoresce. Nasal and conjunctival smears from calicivirus-infected cats did not fluoresce.

Animals↗
PubMed1978

Feline salmonellosis. A nosocomial outbreak and experimental studies.

An outbreak of S. typhimurium gastroenteritis and septicemia is described in young cats admitted to a veterinary hospital for routine medical and surgical reasons. A morbidity of 32% and a mortality of 61% was observed in the outbreak. Affected cats exhibited oral shedding of the organism and contaminated feed and water dishes may have been the vehicle of spread of infection. Possible detrimental effects of incorrect choice of antibiotic therapy are discussed. Attempts to reproduce the disease in a group of laboratory cats were unsuccessful. Antibody production was poorly correlated with infection in these cats.

Animals↗
PubMed1977

Feline Panleukopenia. I. Pathogenesis in germfree and specific pathogen-free cats.

Germfree and specific pathogen-free cats were inoculated panleukopenia vivus. Total leucocyte counts decreased significantly in both germfree and specific pathogen-free cats. Clinical illness was not seen in any germfree cat. Specific pathogen-free cats had anorexia and slight diarrhea 5-6 days after inoculation. None of the cats died. Both germfree and specific pathogen-free cats had thymic involution. No other gross lesions were seen. Tissues for histological virus isolation and immunofluorescence studies were taken daily from days 2 through 6 after inoculation. Virus-infected cells and lesions of panleukopenia were seen in the small intestine of both germfree and specific pathogen-free cats. The incidence of virus-infected cells and lesions was greater in specific pathogen-free cats than in germfree cats.

Animals↗
PubMed1977

Feline panleukopenia. II. The relationship of intestinal mucosal cell proliferation rates to viral infection and development of lesions.

Proliferation rates of small intestinal mucosal cells of noninfected germfree and specific pathogen-free kittens were compared to the incidence of infected cells and microscopic lesions in kittens experimentally infected with panleukopenia virus. Mucosal crypt length, cells per crypt, mitotic index and villous length were greater in specific pathogen-free kittens than in germfree kittens. Crypt cells per unit length and villous length per crypt length ratio were greater in germfree kittens. The cryptal cell proliferation rate of specific pathogen-free kittens was 2.24 times that of germfree kittens. Mucosal crypt length, cell per crypt and villous length were greater in the proximal jejunum than in the midjejunum of kittens within groups. Cell proliferation rates per crypt did not differ between areas of the intestine in kittens within groups. There were more virus-infected cells and lesions in specific pathogen-free kittens than in germfree kittens. The incidence of virus-infected cells and lesions was greater in the proximal jejumum and decreased along the small intestine.

Animals↗
PubMed1977

Evaluation of a feline viral rhinotracheitis-feline calicivirus disease vaccine.

An attenuated respiratory disease vaccine against feline viral rhinotracheitis (FVR) and feline calicivirus (FCV) disease was evaluated for safety and efficacy in specific-pathogen-free cats. Twenty cats were vaccinated twice intramuscularly, with 28 days between vaccinations. Ten unvaccinated cats were used as contact controls. Adverse effects were not noticed after vaccination, and the vaccinal virus did not spread to contact controls. Arithmetical mean serum-neutralizing titers against vaccinal FCV strain F9 and challenge FCV strain 255 were 1:13 and 1:15 at 28 days after the 1st inoculation. These titers increased to 1:45 and 1:196 after the 2nd inoculation. After challenge exposure of vaccinated cats to virulent FCV 255 virus, mean titers increased to 1:129 and 1:865, respectively for F9 and 255 viruses. The F9 postchallenge mean titer for vaccinated cats was 21.5 times higher than that for the 8 contact controls that survived challenge exposure. The arithmetical mean serum neutralizing titer for FVR was low (1:2) after the 1st vaccination, but increased to 1:35 after the 2nd vaccination. Challenge exposure to virulent FVR virus resulted in a marked anamnestic immune response (mean titer of 1:207, compared with 1:12 for contact controls). In general, vaccinated cats remained alert and healthy after challenge exposure with FCV-255, whereas unvaccinated contact control cats developed definite signs of FCV disease, including central nervous system (CNS) depression (6 of 10) and dyspnea indicative of pneumonia (5 of 10). Two controls died of severe pneumonia. A mild fibrile response was detected in 28% of vaccinated cats, compared with a more severe febrile response in 78% of control cats. Some vaccinated cats developed minute lingual ulcers that did not appear to be detrimental to the health of the cat. After FVR challenge exposure, vaccinated cats were free of serious clinical signs. Five of 18 vaccinated cats had mild signs of FVR, including an occasional sneeze, low temperature, and mild serous lacrimation for 1 or 2 days. Contact controls developed definite clinical signs of FVR. The combined FVR-FCV vaccine appears to be safe and reasonably efficacious. Vaccination against FCV disease and FVR should be part of the routine feline immunization program.

Animals↗
PubMed1976

Fetal and adult bovine interferon production during bovine viral diarrhea virus infection.

Levels of interferon in adult bovine serum and in fetal bovine serum and tissues were examined during the course of transplacental bovine viral diarrhea virus infection. The cows produced circulating interferon between 2 and 9 days after viral inoculation, with mean peak levels in the serum on day 4. Interferon could be routinely detected in fetal tissues (e.g., thymus, spleen, and kidney) between days 4 and 21 after viral inoculation of the cows at 149 to 150 days of gestation (mid-second trimester) and in fetal serum from day 13 through day 21. Interferon was also detectable in the serum and tissues of fetuses from dams infected at day 95 of gestation (the beginning of the second trimester). In general, no differences were found between the ability of the adult and fetus to produce interferon. Fetal lamb kidney cells were more sensitive to the antiviral effects of bovine interferon than were fetal bovine kidney cells. The antiviral substance from the fetal and adult animals was characterized as interferon by standard criteria.

Age Factors↗