Investigation of Keyes skin biopsy instrument for intestinal biopsy versus a standard biopsy technique

A prospective, clinical trial was conducted using 12 dogs that were presented for intestinal biopsy. Comparisons were made between paired jejunal biopsies collected using a Keyes biopsy punch and a standard scissor excisional technique. There were no differences in speed of collection, diagnostic value of specimens, complication rates, or sample quality. In this study, the Keyes skin punch was found to be safe, rapid, and diagnostic in all animals. Based on results of this study, the use of a Keyes punch instrument can be recommended as an alternative to other open intestinal biopsy methods.     

Differential diagnosis of granulomatous meningoencephalomyelitis, distemper, and suppurative meningoencephalitis in the dog

Clinical differences were determined between granulomatous meningoencephalomyelitis, distemper, and suppurative meningoencephalitis in the dog. Dogs with granulomatous meningoencephalomyelitis had "head" signs on examination, which progressed to profound caudal fossa abnormalities, changes in mental status, and tetraparesis. Dogs with distemper had a gradual onset of posterior paresis; tetraparesis and occasional vestibular signs developed later in the course of disease. Dogs with suppurative meningoencephalitis had lethargy and anorexia at the time of examination, which progressed to nuchal rigidity, mental depression, tetraparesis, and profound alterations in consciousness. Analysis of cerebral spinal fluid was useful in distinguishing suppurative meningoencephalitis from the other 2 diseases. Twenty-seven cases of inflammatory disease of the CNS in dogs were reviewed. Comparisons of history, results of physical and neurologic examinations, ancillary data, and response to treatment were made. It appeared that certain clinical and neurologic features contributed to the diagnosis of these diseases.     

Experimental transmission of US scrapie agent by nasal, peritoneal, and conjunctival routes to genetically susceptible sheep

Scrapie is a naturally occurring fatal neurodegenerative disease of sheep and goats. This study documents incubation periods, pathologic findings, and distribution of abnormal prion proteins (PrP(Sc)) by immunohistochemistry in tissues of genetically susceptible sheep inoculated with US sheep scrapie agent. Four-month-old Suffolk lambs (QQ at codon 171) were inoculated by 1 of 3 different routes (nasal, peritoneal, and conjunctival) with an inoculum (No. 13-7) consisting of a pool of scrapie-affected sheep brains. Except for 3 sheep, all inoculated animals were euthanized when advanced clinical signs of scrapie were observed between 19 and 46 months postinoculation (MPI). Spongiform lesions in the brains and labeling of PrP(Sc) in central nervous system and lymphoid tissues were present in these sheep. One intranasally inoculated sheep euthanized at 12 MPI had presence of PrP(Sc) that was confined to the pharyngeal tonsil. These results indicate that the upper respiratory tract, specifically the pharyngeal tonsil, may serve as a portal of entry for prion protein in scrapie-infected environments.     

Bronchial carcinoma in a red-shouldered hawk (Buteo lineatus)

Respiratory neoplasms are rare in birds. This report describes carcinoma of the bronchial epithelium in a red-shouldered hawk (Buteo lineatus) that presented with weakness and lethargy lasting 4 days that progressed to seizures. Grossly, the caudal air sac and coelomic cavity contained approximately 15 ml of dark brown cloudy fluid that displaced the intestines cranially. Nodular plaques were present on the viscera and air sacs. Microscopic examination of tissues revealed a mass that expanded the bronchial lumen and was composed of papillary proliferations of rows of small cuboidal epithelial cells that were small and uniform in size with a low mitotic index. Metastases were present on the surfaces of caudal air sac, kidney, and multifocal peritoneal surfaces of the coelomic cavity. Clinical signs were most likely the result of West Nile virus infection, which was confirmed by immunohistochemistry of brain tissue.     

An improved immunohistochemical diagnostic technique for canine leptospirosis using antileptospiral antibodies on renal tissue.

The purpose of this study was to compare the immunoreactivity in canine renal tissues stained with antisera specific for 3 leptospiral antigens and those processed with traditional staining methods. In addition, immunoglobulin staining was done on tissues with immunoreactivity to leptospiral antigens. Formalin-fixed renal sections from 12 dogs with chronic interstitial nephritis suspected or proven to have leptospirosis (6 dogs with silver-stained leptospires and 6 dogs in which silver-stained leptospires were not detected) were used. Antibodies consisted of a monoclonal antibody to Leptospira kirschneri serovar grippotyphosa lipopolysaccharide (LPS) and 2 polyclonal antibodies to outer membrane proteins, including OmpL1, a leptospiral porin, and LipL41, an outer membrane lipoprotein. The murine monoclonal antisera against LPS (F71C2-1) had the most abundant and consistent immunoreactivity. Immunoreactive areas were present in 6 of 6 sections positive by silver staining and included extracellular granular debris in intertubular areas, debris in macrophages, organisms in tubular lumina, and cytoplasmic granules in tubular epithelia. Antisera with specificity for the outer membrane proteins OmpL1 and LipL41 detected only intact organisms in tubular lumina. Immunoreactivity to OmpL1 (polyclonal 338) occurred in 4 of 5 sections positive by silver staining, but immunoreactivity to LipL41 (polyclonal 813) occurred in only 1 of 6 silver-positive sections. Each of the kidney sections in which leptospiral antigens were detected by immunohistochemistry also was positive by silver staining. Sections negative by silver staining were also negative by immunostaining. Although immunohistochemistry did not enhance sensitivity, amplification of signal by secondary antibody and hematoxylin counterstaining improved the ease of diagnosis and allowed better evaluation of tissue morphology than did silver staining methods. IgG was the most abundant immunoglobulin. IgG immunoreactivity occurred predominantly in plasma cells within interstitial infiltrates. Interstitial infiltrates contained abundant immunoreactivity to LPS, but immunoreactivity to OmpL1 and LipL41 was not noted.     

Farm health surveillance in the Marshfield Epidemiologic Study Area: a pilot study

Surveillance of agricultural work-related illness and non-fatal injuries is limited and considered to be a major gap in prevention and policy-making capacity. This pilot study evaluated the utility of the Marshfield Epidemiologic Study Area (MESA) and its farm residency cohort to identify and monitor potential priorities for prevention and control. MESA is a defined geographic region that serves as a resource for conducting population-based health research. Nearly all of the residents receive their health care from the Marshfield Clinic and affiliated hospitals, providing archived electronic medical information to characterize past and present diagnoses. Based on scientific literature and national research priorities, five broad health issues (injuries, back problems, hearing loss, respiratory conditions, and dermatologic conditions) were selected. To estimate age-specific and age-adjusted incidence and prevalence, we followed a fixed cohort of 1995 MESA residents through 2002. Standardized incidence ratios and standardized prevalence ratios were also estimated to quantify the potential impact of farm residency. Linking MESA, its farm residency cohort, and the clinic's data archives allowed successful identification of significant associations with agricultural exposure for a few conditions and subconditions related to consensus priorities in agricultural health, particularly among men. These included extrinsic alveolitis, organic dust toxic syndrome, back pain, osteoarthrosis, and certain injuries. However, the system was generally not able to demonstrate strong influence of farm residency on disease occurrence for many conditions specifically selected for their likely capacity to show such influence. Future surveillance systems should supplement clinical data with other sources of information on health events and should be adequately powered to focus on narrower ranges of health conditions.     

Acetone precipitation of the scrapie agent results in successful recovery of PrP(Sc) but decreased infectivity

Bioassay is considered the most sensitive method for evaluating prion inactivation procedures. Because prions are resistant to methods effective at inactivating conventional microorganisms, prion inactivation research has focused on relatively harsh alternatives, such as concentrated sodium hypochlorite or sodium hydroxide. Often, bioassay for residual infectivity in these studies requires dilution or biochemical alteration of the treated sample in order to maintain subject health and survival. Ideally, prions from treated samples could be sufficiently separated from the inactivating agent without alteration of the sample and with negligible loss of infectivity prior to inoculation into the bioassay host. The current study was designed to evaluate acetone precipitation of the disease-associated form of the prion protein (PrP(Sc)) from brain homogenate derived from mice with the RML (Rocky Mountain Laboratory) strain of scrapie. The ability to recover PrP(Sc) was evaluated by Western blot. Dilutions of acetone-precipitated RML-positive brain homogenate were compared to nonprecipitated RML homogenate, resulting in similar PrP(Sc) detection levels down to 0.025 mg equivalents of brain tissue. The impact of the method on infectivity was investigated by bioassay in intracranially inoculated tga20 mice. Additionally, contributions to infectivity from the pellet and supernatant fractions were investigated. Acetone precipitation resulted in a 1-log?? reduction in infectivity. Infectivity could not be reconstituted by the acetone soluble fraction of the infectious sample or uninfected brain. This study demonstrates that PrP(Sc) can successfully be precipitated out of infected brain homogenate using acetone but that there is a reduction in infectivity attributable to the procedure that would need to be considered when evaluating bioassay results.