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Biomedical subjects

D P Shaw

Publications and source records attributed to D P Shaw.

At least 19 recordsLinked to original sources
PubMed2006

Clostridium piliforme infection in two farm-raised white-tailed deer fawns (Odocoileus virginianus) and association with copper toxicosis.

Necropsy of 2 white-tailed deer fawns who died acutely revealed diarrhea and melena in case No. 1 and no gross changes in case No. 2. Histologically, the livers of both deer displayed multifocal coagulative necrosis, with infiltrations of neutrophils, macrophages, and lymphocytes. By Warthin-Starry staining, bundles of filamentous bacteria were identified within hepatocytes at the periphery of the necrotic foci in case No. 1. There was multifocal myocardiocyte necrosis in case No. 1 and multifocal lymphoid necrosis of the Peyer's patches in case No. 2. Clostridium piliforme 16S ribosomal ribonucleic acid gene was detected in both livers by polymerase chain reaction (PCR) with C. piliforme-specific primers. The liver copper levels in both cases were normal to slightly elevated. The kidney copper level in case No. 2 was elevated. This represents the first published cases of Tyzzer's disease in deer, a novel use of PCR for the diagnosis of C. piliforme infection, and a possible association between copper toxicosis and Tyzzer's disease.

Animal Diseases↗
PubMed2003

Summary of the 2001-02 Pennsylvania H7N2 low pathogenicity avian influenza outbreak in meat type chickens.

H7N2 low-pathogenicity (LP) avian influenza (AI) virus was isolated from chickens submitted to the Pennsylvania Animal Diagnostic Laboratory System on December 4 and 5, 2001. The cases were from two broiler breeder flocks in central Pennsylvania that had clinical signs of an acute, rapidly spreading respiratory disease. Seroconversion to AI virus was detected on follow-up sampling. Subsequently, H7N2 LPAI virus was isolated in five different broiler flock cases submitted between December 14, 2001, and January 3, 2002. Clinical signs and lesions in broilers, when present, were compatible with multicausal respiratory disease. With the exception of one broiler flock that was processed, birds from all of the virus positive flocks were euthanatized in-house within 11 days of the original case submission date. Increased surveillance of poultry flocks within 10-mile radius zones centered at the foci of the positive farms continued until March 1, 2002. No additional cases were detected.

Animals↗
PubMed2002

Pathogenesis of avian pneumovirus infection in turkeys.

Avian pneumovirus (APV) is the cause of a respiratory disease of turkeys characterized by coughing, ocular and nasal discharge, and swelling of the infraorbital sinuses. Sixty turkey poults were reared in isolation conditions. At 3 weeks of age, serum samples were collected and determined to be free of antibodies against APV, avian influenza, hemorrhagic enteritis, Newcastle disease, Mycoplasma gallisepticum, Mycoplasma synoviae, Mycoplasma meleagridis, Ornithobacterium rhinotracheale, and Bordetella avium. When the poults were 4 weeks old, they were inoculated with cell culture-propagated APV (APV/Minnesota/turkey/2a/97) via the conjunctival spaces and nostrils. After inoculation, four poults were euthanatized every 2 days for 14 days, and blood, swabs, and tissues were collected. Clinical signs consisting of nasal discharge, swelling of the infraorbital sinuses, and frothy ocular discharge were evident by 2 days postinoculation (PI) and persisted until day 12 PI. Mild inflammation of the mucosa of the nasal turbinates and infraorbital sinuses was present between days 2 and 10 PI. Mild inflammatory changes were seen in tracheas of poults euthanatized between days 4 and 10 PI. Antibody to APV was detected by day 7 PI. The virus was detected in tissue preparations and swabs of nasal turbinates and infraorbital sinuses by reverse transcription polymerase chain reaction, virus isolation, and immunohistochemical staining methods between days 2 and 10 PI. Virus was detected in tracheal tissue and swabs between days 2 and 6 PI using the same methods. In this experiment, turkey poults inoculated with tissue culture-propagated APV developed clinical signs similar to those seen in field cases associated with infection with this virus.

Animals↗
PubMed2001

Immunohistochemical detection of avian pneumovirus in formalin-fixed tissues.

An immunohistochemical staining technique (IHC) was developed to detect avian pneumovirus (APV) antigen in formalin-fixed, paraffin-embedded tissue sections using streptavidin-biotin immunoperoxidase staining. Samples of nasal turbinates and infraorbital sinuses were collected from 4-week-old poults experimentally inoculated with APV and from older turkeys infected during naturally occurring outbreaks of avian pneumovirus. Tissue was fixed in 10% buffered neutral formalin, embedded in paraffin, sectioned and stained. Inflammatory changes were observed microscopically in the mucosa and submucosa of the nasal turbinates and infraorbital sinuses of both experimentally inoculated poults and naturally infected birds. Viral antigen was detected by IHC in the ciliated epithelial cells of nasal turbinates and infraorbital sinuses.

Animals↗
PubMed2001

Susceptibility of ducks to avian pneumovirus of turkey origin.

OBJECTIVE: To determine the susceptibility of ducks to avian pneumovirus (APV) of turkey origin. ANIMALS: 30 Pekin ducks that were 2 weeks old. PROCEDURE: Ducks were assigned to 3 groups (10 ducks/group). Ducks of groups 1 and 2 were inoculated (day 0) with 200 microl of cell-culture fluid containing APV of turkey origin (10(5.5) median tissue-culture infective dose/ml) by the oculonasal (group 1) or oral (group 2) route. Ducks of group 3 served as noninoculated control birds. Two ducks from each group were euthanatized 3, 6, 9, 15, and 21 days after inoculation. Blood samples, tissue samples from the lungs, trachea, nasal turbinates, duodenum, diverticulum vitellinum (Meckel's diverticulum), and cecum, and swab specimens from the choana, cloaca, and trachea were obtained from all birds during necropsy and examined for APV by use of reverse transcriptase-polymerase chain reaction (RT-PCR), virus isolation, and histologic examination. Blood samples also were examined for APV antibodies, using an ELISA. RESULTS: Tissue samples obtained up to 21 days after inoculation had positive results when tested by use of RT-PCR. Virus was isolated from nasal turbinates of birds inoculated via the oculonasal route. Serum samples obtained 15 and 21 days after inoculation had positive results when tested for APV-specific antibody. Clinical signs of disease were not observed in ducks inoculated with APV of turkey origin. CONCLUSIONS AND CLINICAL RELEVANCE: Ducks inoculated with APV of turkey origin may not develop clinical signs of disease, but they are suspected to play a role as nonclinical carriers of APV.

Animals↗
PubMed2000

Specific detection of avian pneumovirus (APV) US isolates by RT-PCR.

This report details the development of an RT-PCR assay for the specific detection of US isolates of avian pneumovirus (APV). Of the several primer pairs tested, two sets of primers derived from the matrix gene of APV were able to specifically detect the viral RNA of APV. The nucleotide sequence comparison of the PCR products of APV isolates from Minnesota suggested that these viruses were closely related to the Colorado strain of APV, but were distinct from subtypes A and B European isolates of turkey APV (turkey rhinotracheitis: TRT). This M gene-based PCR was found to be very specific and sensitive. APV as low as 8 x 10(-5) TCID50 (0.0323 microg/ml) could be detected using this assay. In addition, the two primers were able to differentiate isolates from turkeys in Minnesota.

Animals↗
PubMed2000

Isolation of avian pneumovirus from an outbreak of respiratory illness in Minnesota turkeys.

Antibodies to avian pneumovirus (APV) were first detected in Minnesota turkeys in 1997. Virus isolation was attempted on 32 samples (28 tracheal swabs, 4 pools of trachea and turbinates) that were positive for APV by reverse transcriptase polymerase chain reaction (RT-PCR). The cell cultures used were chicken embryo fibroblast (CEF), Vero cells, and QT-35 cells. Five virus isolates were obtained from these samples, and the identity of the isolates was confirmed by RT-PCR. Four isolates were obtained by inoculation of CEF cells, and 1 isolate was obtained in QT-35 cells after 3-7 blind passages in cell cultures. Vero cells did not yield any isolate on primary isolation; however, all 5 isolates could be adapted to grow in Vero cells following primary isolation in CEF or QT-35 cells. This is the first report of isolation of APV in Minnesota and also the first report of primary isolation of APV in QT-35 cells.

Animals↗
PubMed1997

The mechanism of blood flow in cardiopulmonary resuscitation--introducing the lung pump.

The mechanism of blood flow in cardiopulmonary resuscitation remains controversial. Inconsistencies in the cardiac pump model necessitated the development of the thoracic pump. Neither hypothesis alone can account for blood flow during external massage. Using the postulates that a cyclical pump has three components, an inlet valve, a compression chamber and an outlet valve, we propose the lung pump hypothesis where these components are represented by the pulmonary valve; the lung vasculature/left atrium/left ventricle; and the aortic valve. We explore the mechanism and effect of this hypothesis and match it to previous observations. The implications to cardiopulmonary resuscitation are addressed.

Animals↗
PubMed1996

Predictors of atrial fibrillation after coronary artery surgery. Current trends and impact on hospital resources.

BACKGROUND: Atrial fibrillation (AF) after coronary artery bypass surgery (CABG) is the most common sustained arrhythmia. Its pathophysiology is unclear, and its prevention and management remain suboptimal. The aim of this prospective study was to determine the current incidence of AF, identify its clinical predictors, and examine its impact on resource utilization. METHODS AND RESULTS: Over a 12-month period ending July 31, 1994, a CABG procedure was performed on 570 consecutive patients (age range, 32 to 87 years; median age, 67 years; 232 [41%] were > or = 70 years; 175 [31%] were women; 173 [30%] were diabetics; 364 [65%] required nonelective surgery; 86 [15%] had had a prior CABG; and 86 [15%] had had prior percutaneous transluminal coronary angioplasty). AF occurred in 189 patients (33%). The median age for patients with AF was 71 years compared with 66 for patients without (P = .0001). Multivariate logistic regression analysis (odds ratio, +/- 95% CI, P value) was used to identify the following independent predictors of postoperative AF: increasing age (age 70 to 80 years [OR = 2; CI, 1.3 to 3; P = .002], age > 80 years [OR = 3; CI, 1.6 to 5.8; P = .0007]), male gender (OR = 1.7; CI, 1.1 to 2.7; P = .01), hypertension (OR = 1.6; CI, 1.0 to 2.3; P = .03), need for an intraoperative intraaortic balloon pump (OR = 3.5; CI, 1.2 to 10.9; P = .03), postoperative pneumonia (OR = 3.9; CI, 1.3 to 11.5; P = .01), ventilation for > 24 hours (OR = 2; CI, 1.3 to 3.2; P = .003), and return to the intensive care unit (OR = 3.2; CI, 1.1 to 8.8; P = .03). The mean length of hospital stay after surgery was 15.3 +/- 28.6 days for patients with AF compared with 9.3 +/- 19.6 days for patients without AF (P = .001). The adjusted length of hospital stay attributable to AF was 4.9 days, corresponding to > or = $10 055 in hospital charges. CONCLUSIONS: AF remains the most common complication after CABG and consequently is a drain on hospital resources. Concerted efforts to reduce the incidence of AF and the associated increased length of stay would result in substantial cost saving and decrease patient morbidity.

Adult↗
PubMed1994

Fiberoptic cardioscopy under cardiopulmonary bypass: potential for cardioscopic surgery?

Attempts at cardioscopy have been hampered by the inability to see through blood. We describe a new method of intracardiac fiberscopic visualization performed in sheep using cardiopulmonary bypass, asanguineous cardioplegic arrest, and replacement of intracardiac blood with a clear fluid. Right heart endoscopic visualization was achieved in 4 sheep using a method that could allow extrapolation to a percutaneous approach. Two of these animals were weaned successfully from cardiopulmonary bypass. Venting and flushing aspects of the procedure were of primary importance. Further development of this technique may open the way to percutaneous endoscopically guided intracardiac operations in humans.

Animals↗
PubMed1993

Pathogenesis of hemorrhagic enteritis virus infection in turkeys.

The pathogenesis of hemorrhagic enteritis was investigated in 4-week-old specific-pathogen-free (SPF) turkeys after oral administration of hemorrhagic enteritis virus. The virus antigen was detected and quantified in tissues at various days post-infection (DPI) by an avidin-biotin-enhanced enzyme immunoassay and was located by a monoclonal antibody-based immunoperoxidase (IP) staining technique. In the intestinal tract, low levels of viral antigen were detected from 1 to 3 and 9 to 15 DPI, whereas high antigen levels were found from 4 to 7 DPI. The bursa had viral antigen from 2 to 7 DPI. The plasma fraction of blood was positive for the antigen at day 1 PI and the cellular fraction of blood on day 3 PI. Antigen was first detected in the spleen at 2 DPI and reached a peak on day 6 PI. Initially, the viral antigen was present in a few reticular cells of the spleen and an increase in IP positive cells occurred with time. The maximum number of inclusion bodies in the spleen were found on day 6 PI. Following splenomegaly, viremia resulted in high levels of the virus appearing in the lamina propria of the small intestine. The lamina propria had numerous lymphoreticular cells positive for intranuclear viral inclusions from 5-7 DPI. It was at this time that intestinal congestion and hemorrhage were seen. The results suggest that HEV replicates first in the lymphoid cells of intestinal tract including the bursa, and then in those of the spleen with consequent HEV antigen widely distributed in the body. The time course of the high levels of HEV (mainly 4-7 DPI) in the lymphoid organs (cells), and occurrence of hemorrhagic enteritis (congestion, hyperemia) from 5 to 7 DPI and intestinal hemorrhage (5-8 DPI) appear to suggest that the intestinal lesion may be an immune-mediated response.

Adenoviridae Infections↗
PubMed1992

Ribavirin mitigates wart growth in rabbits at early stages of infection with cottontail rabbit papillomavirus.

The challenge to develop antiviral agents effective against DNA viruses such as human papillomavirus (HPV) has been dependent on finding an animal model which mimics the human forms of the disease. We have used an existing model system for the purpose of measuring the effect of antiviral drugs on the inhibition of growth of these lesions. This was based upon domestic rabbits which efficiently grow cutaneous papillomas (warts) when infected with cottontail rabbit papillomavirus (CRPV). One agent which had shown significant success in achieving these goals was ribavirin. Ribavirin was administered intradermally shortly prior to infection at multiple sites with CRPV. Following daily injections of this drug for eight weeks, we have shown a dose-dependent response which had markedly reduced the number of warts, the time of first appearance of warts and reduced the tumor mass as compared to placebo-treated control animals. At the highest dose of ribavirin tested, 30 mg/kg/day, compared to controls, the average reduction in the number of warts was 52%, the average time of first appearance of warts was 49% longer, and the average mass of the warts was reduced by 98%. No detectable antibodies to CRPV were observed in any of the animals. The only side effects which were observed was focal alopecia, and a decrease in body growth upon prolonged treatment, both of which were completely reversible. Pharmacokinetic studies established the metabolism of ribavirin over a 24-h period of time. Ribavirin administered beginning 12 or 30 days post-infection, while not reducing the number of warts, slightly retarded the growth of warts as determined by date of first appearance of warts and mass of warts.

Animals↗
PubMed1992

Isolation of swine infertility and respiratory syndrome virus (isolate ATCC VR-2332) in North America and experimental reproduction of the disease in gnotobiotic pigs.

A recent epizootic of swine infertility and respiratory syndrome (SIRS) in a Minnesota swine herd was investigated. Examination of a sow, neonatal piglets, and stillborn fetuses obtained during the epizootic from the affected herd revealed interstitial pneumonitis, lymphomononuclear encephalitis, and lymphomononuclear myocarditis in the piglets and focal vasculitis in the brain of the sow. Fetuses did not have microscopic lesions. No cause for the infertility and respiratory syndrome was determined. Therefore, attempts were made to experimentally reproduce the disease. Eleven 3-day-old gnotobiotic piglets exposed intranasally to tissue homogenates of piglets from the epizootic became inappetent and febrile by 2-4 days postexposure and had interstitial pneumonitis and encephalitis similar to that seen in the field outbreak. After 2 blind passages in gnotobiotic piglets, tissue homogenates were cultured on continuous cell line CL2621, and a cytopathic virus (ATCC VR-2332), provisionally named SIRS virus, was isolated. Gnotobiotic piglets exposed intranasally to the SIRS virus developed clinical signs and microscopic lesions that were the same as those in piglets exposed to the tissue homogenates, and the virus was reisolated from their lungs. This is the first isolate of SIRS virus in the United States that fulfills Koch's postulates in producing the respiratory form of the disease in gnotobiotic piglets and the first report of isolation and propagation of the virus on a continuous cell line (CL2621). The virus is designated as American Type Culture Collection VR-2332.

Animals↗
PubMed1991

Cutaneous neoplasia in 340 cats.

A total of 340 cases of cutaneous neoplasia were diagnosed in 340 of 3,564 cats that were examined by biopsy or necropsy during a 41-month period from January 1, 1986 through May 31, 1989. Eighteen types of tumor occurred, but four types comprised 77% of the cases. These were basal cell tumor, 89 cases (26%, mean age 10.3); mast cell tumor, 72 cases (21%, mean age 8.6); squamous cell carcinoma, 52 cases (15%, mean age 11.6); and fibrosarcoma, 50 cases (15%, mean age 10.2). For each of these four types of tumors, peak number of cases occurred in cats older than 10 years. Mast cell tumor was the only tumor diagnosed in cats younger than 1 year. The head was the most common site for basal cell tumors, mast cell tumors, and squamous cell carcinomas. The legs were the most common location of fibrosarcomas. Siamese cats had approximately three times as many mast cell tumors as statistically expected, but only one-fourth as many squamous cell carcinomas. Breed predilection for other skin tumors was not apparent. Sex predilection was not detected for any skin tumor.

Animals↗
PubMed1990

Hepatic myelolipomas in a cat.

A 16-year-old spayed domestic cat was determined to have hepatic myelolipoma. Treatment consisted of incomplete surgical removal. Despite some tumor tissue remaining, the cat did well for 2 years, then died of an undiagnosed illness. Myelolipomas are tumors of extramedullary hematopoietic tissue, and have been reported uncommonly in cats. On the basis of the clinical course in people, myelolipomas were assumed to be benign in cats. The extended survival after incomplete surgical excision of the tumor in our cat supports this assumption.

Animals↗
PubMed1990

Fecal incontinence, urinary incontinence, and priapism associated with multifocal distemper encephalomyelitis in a dog.

A 4-year-old castrated mixed-breed dog had atypical signs of chronic distemper encephalomyelitis. The predominant signs were related to visceral rather than somatic dysfunction. The visceral dysfunction was largely attributable to distemper-associated inflammatory lesions in the spinal cord and resulted in fecal incontinence, urinary incontinence, and priapism. Empirical treatment of the dog resulted in transitory improvement prior to euthanasia performed because of the progressive nature of the encephalomyelitis.

Animals↗