Search PubMed⌕ Search

Biomedical subjects

H L Thacker

Publications and source records attributed to H L Thacker.

At least 55 records · Page 3Linked to original sources
PubMed1985

Studies on the pathogenesis of Salmonella heidelberg infection in weanling pigs.

Experiments were conducted to define the pathogenic potential of Salmonella heidelberg in weanling pigs. Oral inoculation with S heidelberg resulted in severe catarrhal enterocolitis with accumulation of large amounts of fluid in the small intestine and colon. Salmonella heidelberg was demonstrated, with fluorescence microscopy and bacteriologic cultural techniques, to colonize the ileum, to invade ileal mucosal enterocytes, and to reach mesenteric lymph nodes and extraintestinal tissues by 8 hours. In 5 pigs, intestinal loops were surgically prepared and inoculated with S heidelberg (to determine its invasiveness). Microscopically, there were atrophy of villi, erosion of enterocytes, and neutrophilic infiltration in the lamina propria. Ultrastructurally, intracellular bacteria were demonstrated in villous and cryptal enterocytes, as well as in macrophages of the lamina propria. Bacteria were morphologically intact, occurred free and membrane-bound and caused no detectable cytotoxic effect to the cell.

Animals↗
PubMed1985

Ultrastructural characterization of colonic lesions in pigs inoculated with Treponema hyodysenteriae.

Twelve pigs were inoculated orally with pure cultures of Treponema hyodysenteriae. Pigs were necropsied at different time intervals postinoculation; colonic specimens were collected and prepared for light and electron microscopy. The earliest colonic lesion detected by electron microscopy consisted of superficial vascular congestion and dilatation, edema of the lamina propria and intercellular separation of the epithelial cells at the crypt shoulders. This lesion progressed to epithelial cell necrosis and extrusion into the lumen and extravasation of red cells. Large numbers of spirochetes were present and free, between, over and under necrotic epithelial cells whether in place or partially extruded. Spirochetal penetration of colonic enterocytes and intracytoplasmic multiplication were confirmed in this study. The spirochetes were found to invade the epithelial cells only from their lateral borders. The relationship between T. hyodysenteriae and the colonic anaerobes was not determined.

Animals↗
PubMed1984

Effects of subtype variations in the Holland strain of infectious bronchitis virus when applied as a vaccine.

Massachusetts-type infectious bronchitis viruses (IBV) designated H120, from three sources, have been evaluated as vaccines. Significant subtype variations were observed with the different vaccines based upon challenge virus infection and typical IB lesions induced where homologous and heterologous serotypes were used. In numerous cases, there was little agreement between challenge virus recovery from the respiratory tract and the presence or absence and severity of IB lesions. The study indicates that histopathological observations provide a sensitive, reliable indicator of the immune response to IB vaccination and augment the use of challenge virus isolation attempts. The data suggest that the use of the latter criterion alone was insufficient in evaluating IB immunity. The study also demonstrated that IB vaccine strains, although labeled similarly, varied in their immunogenic properties. Manipulation of infectious bronchitis virus (IBV) and other factors should be considered when obtaining and employing vaccine strains from different sources. Complete characterization of IBV vaccine strains used commercially should be stressed together with an appropriate labeling of each.

Animals↗
PubMed1984

Evaluation of criteria for the postmortem diagnosis of mycoplasmal pneumonia of swine.

Ten swine from each of five herds believed to be affected with mycoplasmal pneumonia of swine and ten swine from each of five herds believed to be mycoplasmal pneumonia-free were selected for postmortem study. Lungs from the 100 swine were examined; grossly and microscopically for lesions typical of mycoplasmal pneumonia of swine and culturally and by an indirect immunofluorescent procedure for the presence of Mycoplasma hyopneumoniae. Nineteen of the lungs had both gross and microscopic lesions typical of mycoplasmal pneumonia of swine and 13 (68%) of these were infected, i.e. were culturally and/or indirect immunofluorescent positive. Absence of gross lesions did not prove freedom from mycoplasmal pneumonia, 14 of 73 (19%) grossly normal lungs were found to be infected with M. hyopneumoniae. Comparison of the indirect immunofluorescent and cultural examination, as methods of diagnosing mycoplasma pneumonia, revealed that neither procedure alone was reliable in the case of negative results. Ten lungs were indirect immunofluorescent negative and culturally positive and seven were culturally negative and indirect immunofluorescent positive (11 lungs were positive by both procedures). It was concluded that a definitive diagnosis of mycoplasmal pneumonia of swine requires that M. hyopneumoniae be visualized in indirect immunofluorescent stained lung sections or that it be recovered culturally.

Animals↗
PubMed1983

Fatal cerebrospinal disease caused by Baylisascaris procyonis in domestic rabbits.

Infection with Baylisascaris procyonis, the common roundworm of raccoons, was found to be the cause of an epizootic of fatal CNS disease in domestic rabbits (Oryctolagus cuniculus). Clinical signs included torticollis, ataxia, tremors, and falling. Gross lesions were limited to white, raised nodules (1 to 1.5 mm) on the epicardium, endocardium, and liver serosa, and they were found to be larval granulomas. Microscopic lesions included multifocal myocarditis, multifocal hemorrhagic tracks and associated necrosis and inflammation in the liver, multifocal eosinophilic myositis, focal nephritis, and mild interstitial pneumonia; larval granulomas were seen in the heart, liver, lung, and mandibular salivary gland. Lesions in the brain consisted of multifocal areas of necrosis and inflammation in the cerebrum, cerebellum, midbrain, and medulla, with accompanying perivascular leukocyte aggregates and neuronal and axonal degeneration. Large numbers of large ascarid larvae were seen in the brain. Epidemiologically, infection was linked to the use of contaminated straw from a barn used by raccoons. On the basis of this study as well as that of similar studies, it was concluded that barn use and contamination by raccoons may be an important source of infection of animals and possibly man with this parasite.

Animals↗
PubMed1983

Experimental production of neonatal isoerythrolysis in the foal.

Serological evidence with or without clinical signs of neonatal isoerythrolysis was experimentally produced in 6 of 8 foals born to mares allo-immunized with washed erythrocytes from the stallion. Blood group antigens were determined in all mares, stallions and foals, and the incompatible antigenic factor(s) responsible for the disease were defined. In 5 of 8 foals born to alloimmunized mares, a single antigenic factor difference accounted for the erythrocyte incompatibility between mare and foal. The erythrocyte antigen suspected as the most responsible for isoerythrolysis observed was A1. Agglutinin and hemolysin titers were measured in mare serum and colostrum. Of the presuckle anti-foal erythrocyte titers, colostral and hemolysins titers were greater than serum and agglutinin titers respectively. Foals were allowed to nurse and treatment of affected foals was not attempted which allowed full expression of disease and outcome.

Agglutinins↗
PubMed1983

Evaluation of a series of testing procedures to predict neonatal isoerythrolysis in the foal.

A series of modified (field) tests were compared to a crossmatch between mare and foal for their reliability in predicting neonatal isoerythrolysis (NI) in eight foals born to experimentally alloimmunized mares. In the field tests, mare's serum, plasma and colostrum were combined with foal erythrocytes washed by a modified procedure to determine which combination was the best predictor of impending NI. A consistent grading system for agglutination and hemolysis was employed. The field tests using mare's plasma demonstrated less agglutination and hemolysis than tests where serum was employed. Immediate assessment of agglutination failed to demonstrate agglutinin activity when compared to tests where incubation was included. Rouleaux formation posed a problem in interpretation of minor agglutination, however the grading of hemolysis was simpler, quicker, and more accurate. The field test that was most reliable when compared to the crossmatch and presuckle anti-foal erythrocyte titers in demonstrating agglutinins was the combination of mare's serum and foal's erythrocytes. The tests for hemolysin detection in serum and colostrum which incorporated rabbit sera as a complement source were also reliable.

Agglutination↗
PubMed1983

Fate of autogenous fat implants in the frontal sinuses of cats.

Cats (n = 4) were subjected to a bilateral osteotomy overlying the frontal sinuses. The right sinus of each cat served as a control, and the left sinus was filled with autogenous fat harvested from the subcutaneous region of the ventral part of the abdomen. All 4 cats were euthanatized at 200 days. The experiment was designed to determine whether satisfactory obliteration of the left frontal sinus could be accomplished without the benefit of intraoperative magnification. Grossly, obliteration of all 4 sinuses was accomplished in 3 of 4 cats. Light microscopy revealed fluid and/or regrowth of mucous membrane, both considered to be unfavorable sequelae. Although some fat retained viability in the sinus (50% in one cat, 40% in another), most of the obliteration was from mixed fibrous-adipose tissue or bony ingrowth. The clinical significance of this study was not determined, since all 4 cats were free of sinusitis before adipose tissue implantation.

Adipose Tissue↗
PubMed1982

Cerebrospinal nematodiasis and visceral larva migrans in an Australian (Latham's) brush turkey.

Cerebrospinal nematodiasis and visceral larva migrans were diagnosed in an Australian (Latham's) brush turkey (Alectura lathami) that died at the Indianapolis Zoo following a progressive neurologic disease. Histologically, multifocal areas of malacia, necrosis, and inflammation were seen in sections of cerebrum, cerebellum, and midbrain; lesions were most severe in the cerebellum. A large granuloma in a lung contained cross sections of a large ascarid larva identified as Baylisascaris. The CNS lesions were typical of larval migration, as documented in other avian species. An epizootiologic investigation indicated that Baylisascaris procyonis was the etiologic agent and that the bird had acquired the parasite through contact with fecal contamination from wild raccoons at the St Louis Zoo, where the bird had been raised.

Animals↗
PubMed1981

Cerebrospinal Nematodiasis in a woodchuck suspected of having rabies.

A young woodchuck (Marmota monax) with a history of CNS dysfunction and abnormal behavior was submitted frozen to the Animal Disease Diagnostic Laboratory, Purdue University, as a rabies suspect. The woodchuck was negative for rabies by the fluorescent antibody test. Histologically, multifocal areas of necrosis, malacia, and inflammation were seen in sections of cerebrum, midbrain, and cerebellum, accompanied by marked perivascular cuffing with eosinophils and lymphocytes. Sections of lung contained parasitic granulomas, one of which contained a large ascarid larva identified as Baylisascaris sp. The CNS lesions were typical of parasite migration, and resembled those commonly associated with infection with Baylisascaris larvae of raccoon or skunk origin. Cerebrospinal nematodiasis was diagnosed as the cause of the nervous disorder.

Animals↗
PubMed1981

Vaccination-induced distemper in kinkajous.

Following vaccination for distemper, using a modified live-virus vaccine developed for dogs, 2 young kinkajous (Potos flavus) developed diarrhea, then central nervous system disease. Clinical signs included myoclonus, head trembling, loss of muscular coordination, and convulsions. One kinkajou gradually recovered; the other seemed to recover, then relapsed and was euthanatized. Microscopic lesions included those of interstitial pneumonia and enteritis and multifocal lymphocytic inflammation, gliosis, spongiosis, and swollen and degenerating axons in the cerebral, cerebellar, and brain stem white matter. Similar lesions were found at all caudally, as exemplified by complete destruction of the dorsal funiculi and dorsal horns of the gray matter of the upper sacral cord segments. Eosinophilic intranuclear inclusions were seen histologically in the glia in the spinal cord, midbrain, and cerebellum, and were confirmed as canine distemper viral inclusions by the fluorescent antibody method. It was concluded that modified live canine distemper virus vaccines should be used with caution or not at all in kinkajous.

Animals↗
PubMed1979

Agammaglobulinemia in a horse.

Immunologic deficiency was suspected in an 18-month-old Standardbred horse with persistent fever, multifocal bacterial infection, and neutropenia with a large number of immature neutrophils. Serum protein electrophoresis revealed marked depression of the gamma-globulin fraction (0.2 g/100 ml). Immunologic testing and histologic examination of lymphoid tissues identified the immune deficit as agammaglobulinemia. Serum concentrations of immunoglobulin (Ig)G and IgG(T) were initially low and declined with time; IgM and IgA were not detectable. The horse failed to produce antibodies when inoculated with foreign antigens but had a positive cell-mediated skin reaction to intradermal phytolectin injection, and lymphocytes responded normally to in vitro stimulation by mitogens. Histologic examination of lymphoid tissues revealed absence of germinal centers and plasma cells.

Agammaglobulinemia↗
PubMed1979

Ovine pulmonary cytomegalovirus.

Cytomegalic cells with intranuclear inclusions were identified in lung tissue from one of two weanling Western lambs with pneumonia and Mycoplasma ovipneumoniae infection. On the basis of light and electron microscopy, cytomegalovirus infection was diagnosed. Arrays of viral particles whose morphology was consistent with that of viruses of the herpes group were in the intranuclear inclusions of cytomegalic cells.

Animals↗