PubMed Health⌕ Search

Biomedical subjects

T R Schoeb

Publications and source records attributed to T R Schoeb.

50 records · Page 3Linked to original sources
PubMed1986

Evaluation by scoring and computerized morphometry of lesions of early Mycoplasma pulmonis infection and ammonia exposure in F344/N rats.

To evaluate lesions of ammonia exposure and Mycoplasma pulmonis infection in gnotobiotic F344/N rats, groups of rats were inoculated with M. pulmonis, exposed to 76 micrograms/liter (100 parts per million) ammonia, or both, or served as controls. Six rats from each group were killed 3, 5, 7, and 9 days after inoculation and their respiratory organs prepared for histologic examination. Lesions were assessed by subjective scoring and computerized morphometry, and results obtained by the two methods were compared to assess agreement of results. Lesions were limited to the nasal passages. Ammonia exposure resulted in hyperplastic and degenerative changes in the anterior nasal epithelium. Lesions of mycoplasmosis were more severe in ammonia-exposed than unexposed rats, but qualitative differences in lesions were not apparent. Results of the two methods agreed in assessment of submucosal inflammatory cell accumulation. Epithelial lesions were difficult to evaluate by both methods in infected, ammonia-exposed rats. In evaluation of lesions of ammonia exposure alone, agreement was adequate. Both methods indicated that exudates were significantly greater in ammonia-exposed infected rats than in non-exposed infected rats. Thus, scoring and morphometry provided similar assessments of differences in lesion severity among the treatment groups.

Ammonia↗
PubMed1986

Rotavirus-associated diarrhea in a commercial rabbitry.

An epizootic of diarrheal disease occurred in a commercial specific-pathogen-free rabbitry, and was characterized by sudden onset, rapid spread, and high morbidity and mortality among sucklings. Affected rabbits rapidly became dehydrated and most died within two days of the onset of diarrhea. Eight of these rabbits were necropsied. Five had blunted and fused small intestinal villi with attenuated villous enterocytes. A rotavirus was isolated from four rabbits, and five survivors of affected litters had strong antibody responses to rotavirus.

Animals↗
PubMed1985

Exacerbation of murine respiratory mycoplasmosis in gnotobiotic F344/N rats by Sendai virus infection.

Six- to eight-week-old gnotobiotic F344/N rats were inoculated intranasally with 10(5.0) colony-forming units of Mycoplasma pulmonis or were sham inoculated, then one week later were given 10(0.2) 50% tissue culture infective doses of Sendai virus or sterile medium. Groups of rats were killed immediately after virus inoculation and three, five, ten, and 20 days later. Lesions in nasal passages, middle ears, larynxes, tracheas, and lungs from half of the rats in each group were subjectively scored. Organs from the other rats were quantitatively cultured for M. pulmonis and for Sendai virus. Rats given Sendai virus alone had mild, patchy, necrotizing rhinitis, laryngitis, tracheitis, and bronchitis, but not bronchiolitis or interstitial pneumonia. M. pulmonis alone induced mild lesions of murine respiratory mycoplasmosis including mild to moderate suppurative rhinitis, otitis media, laryngitis, and tracheitis with submucosal lymphoid accumulation and epithelial hyperplasia, but not lung lesions. Rats given M. pulmonis and Sendai virus had severe lesions characteristic of advanced mycoplasmal disease throughout the respiratory tract, including suppurative bronchitis with extensive lymphoid accumulations and epithelial hyperplasia; some rats also had suppurative pneumonia and bronchiectasis. Larger numbers of M. pulmonis colony-forming units were in rats given Sendai virus, but there was no statistically significant difference in Sendai virus infectious units between rats also given M. pulmonis and those given virus only.

Animals↗
PubMed1985

Mycoplasma pulmonis-host relationships in a breeding colony of Sprague-Dawley rats with enzootic murine respiratory mycoplasmosis.

The longitudinal Mycoplasma pulmonis-host relationships in rats 1 to 72 weeks of age were investigated in a conventional breeding colony of Sprague-Dawley rats with enzootic murine respiratory mycoplasmosis (MRM). Mean intracage ammonia (NH3) concentrations of 52 +/- 21 micrograms/1 and active Sendai virus infections during the first month of life were associated with important early events in MRM. There was rapid colonization of proximal airways by large numbers of M. pulmonis in most rats by 2 weeks of age and the lungs by 6 weeks. The prevalence of lesions of MRM peaked by 3 weeks in nasal passages, later in middle ears, larynx and trachea, and not until 8 weeks in lungs. Approximately 10% of rats 8 weeks of age and older had bronchiectasis and/or bronchiolectasis, usually restricted to a few airways. Despite continued high NH3 concentrations (42 +/- 14 micrograms/1 in cages of weanlings and 86 +/- 45 micrograms/1 in cages of adults), M. pulmonis populations declined dramatically by 8 weeks of age. Nevertheless, in older rats lesions continued to be extremely prevalent in proximal airways. Mycoplasma pulmonis infection and disease persisted in respiratory tracts of most rats through 72 weeks of age, despite high serum concentrations of mycoplasma-specific IgM and IgG antibodies. These interrelationships of M. pulmonis, host, and environment may be representative of many breeding colonies of rats that have enzootic MRM.

Age Factors↗
PubMed1984

Adenoviral infection in infant tree shrews.

An epizootic of fatal illness among infant common tree shrews (Tupaia glis) occurred in a research colony. Affected tree shrews were dehydrated, and ingested milk substitute remained in their stomachs for several hours without being digested. Twelve of 15 tree shrews born during a 3-month period died. The 4 tree shrews we were able to examine had intranuclear inclusions in the epithelium of the stomach and intestines, with mild to moderate multifocal necrosis. One tree shrew also had nasal epithelial inclusions and multiple foci of hepatocellular and biliary necrosis, with inclusions. The causative virus was identified as an adenovirus.

Adenoviridae↗
PubMed1984

Endometriosis with bacterial peritonitis in a baboon.

An adult female Papio hamadryas being used in reproductive studies was found moribund unexpectedly. Palpation revealed acute abdominal pain and a pelvic mass. A tentative diagnosis of endometriosis and shock was made. Necropsy and histological examination confirmed the diagnosis of endometriosis and identified an associated bacterial peritonitis.

Animals↗
PubMed1982

Intracage ammonia promotes growth of Mycoplasma pulmonis in the respiratory tract of rats.

Ammonia (NH3) from soiled cage bedding is known to enhance the progression and severity of murine respiratory mycoplasmosis in rats. To test the hypothesis that NH3 directly or indirectly enhances the growth of Mycoplasma pulmonis in vivo, pathogen-free F344 rats were inoculated intranasally with 1 x 10(4) to 4 x 10(4) or 4 x 10(6) to 5 x 10(6) colony-forming units of M. pulmonis and exposed to less than or equal to 1.5 or 76 microgram of NH3 per liter (less than or equal to 2 or 100 ppm, respectively). Nasal passages, larynges, tracheas, and lungs from rats killed at intervals up to 28 days after inoculation were quantitatively cultured. Growth of M. pulmonis was much greater in NH3-exposed rats than in controls, particularly in those inoculated with the lower dose. Increases in M. pulmonis populations were more rapid in proximal airways than in distal airways. Serum immunoglobulin G and M antibody responses to M. pulmonis as measured by an enzyme-linked immunosorbent assay were greater in NH3-exposed rats. In other experiments, the nasal passages absorbed virtually all NH3 when the rats were exposed to less than 380 micrograms of NH3 per liter (500 ppm), indicating that NH3 induced increases in the numbers of organisms in the distal respiratory tract, probably by a secondary, rather than a direct, effect. Also, NH3 exposure did not inhibit pulmonary antibacterial activity as measured by clearance of radiolabeled Staphylococcus epidermidis. The growth of M. pulmonis in vitro was inhibited by 1 mM NH4+ added to the medium as NH4OH but not by NH4+ concentrations of 0.5, 0.1, or 0.01 mM, suggesting that NH3 increases growth indirectly through effects on the host.

Absorption↗
PubMed1981

Comparison of methods for detection of Mycoplasma pulmonis in experimentally and naturally infected rats.

Isolation, indirect immunofluorescence, an enzyme-linked immunosorbent assay (ELISA), and histopathological examination of tissues for characteristic lesions were evaluated for their efficiency in detecting Mycoplasma pulmonis infection in rats. Whereas all of the methods were efficient in naturally infected Sprague-Dawley rats, none of the methods consistently detected infection in F344 rats experimentally infected with low doses of the organism. In the experimental infections, however, the success rate of any method was directly related (P less than 0.05) to increasing inoculum dose and time postinoculation. Collectively, the data indicated that isolation of M. pulmonis was the most efficient single detection method and the nasopharyngeal duct was the best single site to culture, although sampling of multiple sites within the respiratory tract increased the rate of isolating the organism. The ELISA was understandably the least sensitive method in the low-dose, experimentally infected rats because of the time required for development of a detectable serum antibody response. Although each of the four methods identified a high percentage of naturally infected rats, the ELISA was the most efficient method in these animals as it was uniformly positive. The use of combinations of methods was found to increase the rate of detection of M. pulmonis infection in both experimentally and naturally infected rats.

Animals↗
PubMed1978

Blister beetle poisoning in horses.

Case records of 21 horses with acute illness following ingestion of hay containing dead striped blister beetles (Epicauta spp) were selected for review. Abdominal pain, fever, depression, frequent urination, shock, and, occasionally, synchronous diaphragmatic flutter characterized clinical illness. Hematologic findings included hemoconcentration, neutrophilic leukocytosis, and hypocalcemia. Hematuria and low urine specific gravity were abnormal urinalysis results. Sloughing of the epithelium of the esophageal part of the stomach, hemorrhagic and ulcerative cystitis, enterocolitis, and myocardial necrosis were important post-mortem findings. Signs and lesions in 5 horses experimentally poisoned were similar to those of the natural disease. The findings were regarded as sufficiently characteristic of blister beetle poisoning to be useful in differential diagnosis but were not constant in all cases. Therefore, when blister beetle poisoning is suspected, access of affected horses to hay containing striped blister beetles should be demonstrated.

Animals↗
PubMed1978

Scrotal and testical changes in canine brucellosis: a case report.

An Irish Setter with scrotal enlargement had an agglutination titer to Brucella canis of greater than or equal to 1:200, but B canis was not cultured from the blood. Unusual findings included draining ulcers in the scrotum from which B canis was cultured, a necrotic testicle, and inflammation of the entire scotum. Other clinical and postmortem findings were as previously described in other cases of naturally occurring and experimentally induced canine brucellosis.

Animals↗