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Biomedical subjects

W J Hadlow

Publications and source records attributed to W J Hadlow.

At least 55 records · Page 3Linked to original sources
PubMed1980

Virologic and neurohistologic findings in dairy goats affected with natural scrapie.

Virologic and neurohistologic findings in three dairy goats that became affected with scrapie while living with naturally infected Suffolk sheep were essentially like those in affected sheep. Virus, detected by mouse inoculation, was widespread in non-neural sites, particularly in lymphatic tissues and intestine. Im most sites, titers of virus ranged from 3.0 to 3.5 log10 mouse intracerebral LD50/30 mg of tissue. Virus was in nervous tissue in much higher titer. Ranging from 5.1 to 5.8 log10, the highest mean titers were in the diencephalon, midbrain, medulla oblongata and cerebellar cortex--sites of the most severe histologic changes. Although these changes were like those in naturally affected Suffolk sheep, they differed somewhat from those in goats affected with the experimental disease. Spongiform alteration of neuropil was minimal, and the more rostral parts of the brain, such as corpus striatum, globus pallidus and septal area, had few changes. Concentrations and distribution of virus in non-neural tissues were consistent with the conclusion that scrapie virus no doubt can be maintained by contagion in a herd of goats living apart from infected sheep.

Animals↗
PubMed1980

Occurrence of pox in a northern fur seal on the Pribilof Islands in 1951.

The presence of pox in a northern fur seal pup, Callorhinus ursinus, examined at necropsy on the Pribilof Islands, Alaska, 13 September 1951 was confirmed by re-examination of formalin-fixed tissues collected at that time. The disease was characterized by multiple 3 to 8 mm modules in the skin of the nose and flippers. Unlike pox lesions in other pinnipeds studied so far, the nodules were discrete dermal epitheliomas free of any direct connections with the overlying atrophic epidermis. They most likely arose from outer sheath cells of hair follicles. The tightly packed epithelial cells forming the nodules contained large, round, eosinophilic, intracytoplasmic inclusion bodies. As demonstrated by electron microscopy nearly 27 years after the tissues were fixed in formalin, poxvirus virions also were present in these cells. These findings indicate pox was present in a northern fur seal, hitherto undescribed in that species, 18 years before the disease was first reported in pinnipeds.

Animals↗
PubMed1978

Sedimentation characteristics of the scrapie agent from murine spleen and brain.

Sedimentation profiles of the scrapie agent in extracts of murine spleen and brain were determined by analytical differential centrifugation. Infectivity profiles of the agent from the two tissues were similar. Sedimentation of the agent was not substantially altered by detergent treatment with sodium deoxycholate. In the presence of detergent, centrifugation at an omega2t value of 3.0 x 1010 rad2/s in a fixed-angle rotor sedimented 90% of the agent. Comparative studies with radioisotopically labeled Simian virus 40 showed that centrifugation at an omega2t value of 1.6 x 10(10) rad2/s removed 90% of the virions. The sedimentation profile of the scrapie agent was similar to that observed for cellular ribosomal RNA. Heating infectious extracts of spleen to 80 degrees C for 30 min resulted in the destruction of 95% of the RNA while sedimentation of the scrapie agent was unchanged. These studies establish a limited range of particle sizes for the scrapie agent.

Animals↗
PubMed1978

Partial purification and evidence for multiple molecular forms of the scrapie agent.

A procedure for the partial purification of the scrapie agent from mouse spleen was developed based on its sedimentation profile. Differential centrifugation and detergent treatment with sodium deoxycholate yielded a fraction designated "P5" which was enriched for scrapie infectivity approximately 20-fold with respect to cellular protein. The P5 fraction was devoid of cellular membranes but heavily contaminated with ribosomes as judged by electron microscopy. On centrifugation of the fraction P5 to near equilibrium in a sucrose gradient scrapie infectivity was distributed over a range of densities from 1.08 to 1.30 g/cm3. Parallel rate-zonal analysis showed that the infectivity was distributed over a range of particle sizes with s20.w values from approximately 40 S to greater than 500 S. Incubation of P5 at 37 or 80 degrees C, under conditions that disrupt ribosomes, dramatically altered the rate-zonal gradient profile of the agent. Under these conditions, the agent sedimented as particles with s20.w greater than 500 S. The apparent heterogeneity of the scrapie agent with respect to both size and density and its ability to shift from one form to another suggest that the agent may contain hydrophobic domains on its surface.

Animals↗
PubMed1978

High prevalence of thymoma in the dairy goat. Report of seventeen cases.

Among 92 dairy goats, mainly of Saanen breeding, necropsied during studies on slow viral diseases, 17 (25.3%) of 67 over 2 years old had thymoma. Ten were females and seven were castrated males. In none was the thymoma accompanied by clinical signs attributable to it. Except for one at the thoracic inlet, all tumors were in the cranial mediastinal cavity. Encapsulated and sometimes cystic, they varied from a 2-centimeter nodule to a smoothly bosselated 10x8x8-centimeter mass weighing 300 grams. Although they were composed of lymphocytes and epithelial cells, small lymphocytes predominated in 16. One was predominantly epithelial. Hassall's corpuscles and myoid cells were seen in all tumors. In 12 tumors, small veins were encircled by spaces that varied from empty clefts to wide, fluid-filled cavities. The high prevalence of thymoma in these goats supports previous reports that this tumor occurs more often in Capra hircus than in other domestic animals. It may be one of the more common neoplasms in older goats.

Animals↗
PubMed1977

Sedimentation properties of the scrapie agent.

The sedimentation behavior of the scrapie agent in homogenates of spleen from infected mice has been determined. Approximately 90% of the scrapie agent was sedimented at an omega2t value of 3 X 10(10) rad2/sec in a fixed-angle rotor. Sedimentation of the agent was not substantially affected by sonication or by treatment with the detergent sodium deoxycholate. The sedimentation profiles of the scrapie agent were similar to those observed for free polyribosomes, but differed from those exhibited by five other subcellular markers. Comparative studies showed that the sedimentation profiles of subcellular markers in spleen suspensions from mice infected with scrapie did not differ from uninoculated controls. These studies suggest that the scrapie agent is a discrete infectious particle which should be separable from cellular membranes.

Animals↗
PubMed1977

Intracranial myiasis by Hypoderma bovis (Linnaeus) in a horse.

Acute neurologic disease associated with intracranial migration of a first instar larva of a warble fly, Hypoderma bovis (Linnaeus), was observed in a 14-year-old Quarter Horse gelding in western Montana. The disease was characterized by incoordination of gait, circling to the left, head tilt to the right, partial paralysis of the right side of the face, and impaired vision in the right eye. Two and one-half hours after it was first noticed sick, the horse collapsed and was euthanized. Massive hemorrhage unaccompanied by necrosis or significant cellular response was present in the right side of the midbrain and pons.

Animals↗
PubMed1975

Aleutian disease of mink: the antibody response of sapphire and pastel mink to Aleutian disease virus.

The specific antiviral antibody response of sapphire and pastel mink to Pullman strain of ADV has been examined. Sapphire mink inoculated with from 300,000-3 LD50 developed high levels of specific antibody and AD. Pastel mink inoculated with parallel doses of ADV also produced antibody but did not develop AD. The low incidence of AD in pastel mink inoculated with Pullman strain of ADV is probably related to factors other than antiviral antibody.

Aleutian Mink Disease↗