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571 results on '"Murtaugh, Michael P."'

177. Linkage assignment of eleven genes to the porcine genome

Author

Hu, Zhiliang, primary, Rohrer, Gary A., additional, Stone, Roger T., additional, Rutherford, Mark, additional, Osinski, Mark A., additional, Pampusch, Mary S., additional, Murtaugh, Michael P., additional, Brown, David R., additional, and Beattie, Craig W., additional

Published
1997
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193. Manufacturing porcine islets: culture at 22 °C has no advantage above culture at 37 °C: a gene expression evaluation.

Author

Mueller, Kate R., Martins, Kyra V., Murtaugh, Michael P., Schuurman, Henk‐Jan, and Papas, Klearchos K.

Subjects
GENE expression, ISLANDS of Langerhans transplantation, IMMUNE response, OXYGEN consumption, LYMPHOKINES, CHEMOKINES
Abstract

Background The manufacturing process of islets includes a culture step which was originally introduced to ease the logistics of procedures in preparing the graft and transplant recipient. It has been suggested that culture at room temperature has an advantage over culture at 37 °C, in part by reducing immunogenicity via preferential elimination of contaminating cells (such as passenger leukocytes) within islets. We investigated this using islets isolated from pancreata of adult pigs. Methods Porcine islets were isolated from three donors and cultured at 37 °C for 1 day, and then under three different conditions: 37 °C for 6 days (condition A); 22 °C for 6 days (condition B); or 22 °C for 5 days followed by 37 °C for 1 day (condition C). Recovery was assessed by DNA measurement, viability by oxygen consumption rate normalized for DNA ( OCR/ DNA), and gene expression by RT- PCR for a series of 9 lymphocyte markers, 11 lymphokines and chemokines, and 14 apoptotic and stress markers. Results Post-culture islet recoveries were similar for the three culture conditions. Average OCR/ DNA values were 129-159 nmol/min·mg DNA before culture, and 259-291, 204-212, and 207-228 nmol/min·mg DNA, respectively, for culture under conditions A, B, and C, respectively. Irrespective of culture condition, examined gene expression in all three series of lymphocyte markers, lymphokines and chemokines, and apoptotic and stress markers manifested a statistically significant decrease upon culture for 7 days. This decrease was most dramatic for condition A: in particular, most of lymphocyte markers showed a >10-fold reduction and also six markers in the lymphokine and chemokine series; these reductions are consistent with the elimination of immune cells present within islets during culture. The reduction was less for apoptotic and stress markers. For culture under condition B, the reduction in gene expression was less, and culture under condition C resulted in gene expression levels similar to those under condition A: this indicates that 24 h at 37 °C is sufficient to re-equilibrate gene expression levels from those in islets cultured at 22 °C to those in islets cultured at 37 °C. Results were consistent among the preparations from the three donors. Conclusions Culture of porcine islets at 37 °C provides benefits over culture at 22 °C with respect to OCR/ DNA outcomes and reduced expression of genes encoding lymphocyte markers, lymphokines and chemokines, and markers for apoptosis and stress. [ABSTRACT FROM AUTHOR]

Published
2013
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194. Epidemiological study of air filtration systems for preventing PRRSV infection in large sow herds.

Author

Alonso, Carmen, Murtaugh, Michael P., Dee, Scott A., and Davies, Peter R.

Subjects
*PORCINE reproductive & respiratory syndrome, *EPIDEMIOLOGY, *AIR filters, *FILTERS & filtration, *HERDING, *AEROSOLS, *PHYLOGENY, *ANIMAL diseases
Abstract

Abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) is the most economically significant pathogen in the US swine industry. Aerosol transmission among herds is a major concern in pig dense regions and filtration of incoming air, in combination with standard biosecurity procedures, has been demonstrated to prevent transmission of PRRSV into susceptible herds. To quantify the impact of air filtration on reducing risk of PRRSV outbreaks, we compared the incidence rate of new PRRSV introductions in 20 filtered and 17 non-filtered control sow herds in a swine dense region of North America during a 7year study period. Events of novel virus introduction were ascertained by phylogenetic analysis of PRRSV ORF5 gene sequences. Putative new viruses were defined as exogenous (introduced) based on ORF5 nucleotide sequence differences compared to previous farm isolates. The influence of sequence difference cut-off values ranging from 2 to 10% on case definition and relative risk were evaluated. Non-filtered farms incurred about 0.5 outbreaks per year, with a seasonal increase in risk in cooler periods. Baseline risk, prior to filtration, in treatment farms was approximately 0.75 per year, approximately 50% higher than in control farms. Air filtration significantly reduced risk of PRRSV introduction events to 0.06–0.22 outbreaks per year, depending on the cut-off values used to classify a virus isolate as new to the herd. Overall, air filtration led to an approximately 80% reduction in risk of introduction of novel PRRSV, indicating that on large sow farms with good biosecurity in swine-dense regions, approximately four-fifths of PRRSV outbreaks may be attributable to aerosol transmission. [Copyright &y& Elsevier]

Published
2013
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