Herd-level ELISA seroprevalence of bovine viral diarrhea antibodies in bulk-tank milk in Chilean dairy herds     

Meléndez P  Donovan A 《Preventive veterinary medicine》2003,60(3):237-241

Our objective in this cross-sectional study was to determine the seroprevalence in 1996 of commercial dairy herds in central Chile positive to bovine viral diarrhea (BVD) virus, by the detection of antibodies in bulk-tank milk samples. Samples were obtained from 501 dairy farms ( approximately 50,000 cows) from the Metropolitan, VI, VII and VIII regions of Chile. An indirect ELISA was used to detect BVD antibodies. An absorbance (A450) > or = 0.55 was considered positive. The apparent proportion of positive herds ranged from 71.2 to 83% by region and did not differ by region. We concluded that exposure to BVD was widely distributed in the central area of Chile in 1996.  相似文献   

Healthy People 2010--new opportunities for veterinary medicine in the 21st century     

Hendrix CM  McClelland CL  Kahn KL  Thompson I  Pence PA 《Journal of the American Veterinary Medical Association》2002,221(7):951-957

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A Simple Device to Increase Background Contrast in Photomicrography     

Pence RJ 《Science (New York, N.Y.)》1947,105(2732):503-504

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Application of complex compost in the course of winter wheat cultivation     

I. S. Belyuchenko  O. A. Mel’nik 《Russian Agricultural Sciences》2014,40(4):264-266

Influence of complex compost on the agronomical properties of soil, winter wheat development and productivity, and quality of production in the conditions of a farm located in the Leningrad area of Krasnodar territory was considered. The positive action of the complex compost on these indicators was noted.  相似文献   

Seroprevalence and comparison of isolates of endometriotropic bovine herpesvirus-4.     

Kendall S Frazier  Charles A Baldwin  Mel Pence  Joe West  John Bernard  Alan Liggett  Debra Miller  Murray E Hines 《Journal of veterinary diagnostic investigation》2002,14(6):457-462

Sixty-eight cases of suppurative, ulcerative endometritis associated with Bovine Herpesvirus-4 (BHV-4) in postparturient dairy cows (62 Holsteins and 6 Jerseys, mean age 4.2 years) were confirmed by a combination of histopathology, fluorescent antibody assays, electron microscopic evaluation of uterus, and polymerase chain reaction (PCR). All cases occurred in the 3- to 28-day postpartum period, and histologic lesions among various cows were consistent when compared with postpartum interval. The endometrial lining epithelium was necrotic and ulcerated from 3 to 7 days postpartum, with only mild inflammation in the lamina propria and submucosa. From 1 to 4 weeks postpartum, the ulcers were confluent to diffuse. Epithelium was replaced by fibrinonecrotic, suppurative mats, resulting in severe bacterial pyometra by day 24. Seroprevalence to BHV-4 in one dairy with a history of 18 mortality cases was 36% (107 of 296). In a random sample of 8 cows from this herd, none had serologic titers in blood sampled 2 weeks prepartum, but 3 of 8 seroconverted with significant titers of 1:8 to 1:16 at 2 weeks postpartum. By 10 weeks postpartum, all 8 cows returned to negative serologic status. Two of 6 cats from the premises also had positive titers. Random serum samples taken from 480 dairy cattle at sale barns indicated 76 (16%) were positive by serum neutralization. Clinical signs, postparturient timing, and histologic lesions were very similar to those previously reported in Belgium with BHV-4. But sequence analysis of PCR products of the glycoprotein B region of 4 separate field isolates of endometriotropic BHV-4 suggests these field isolates were more closely related to the North American nonvirulent strain DN-599 than to the endometriotropic European strain V.  相似文献   

Autophagy genes are essential for dauer development and life-span extension in C. elegans     

Meléndez A  Tallóczy Z  Seaman M  Eskelinen EL  Hall DH  Levine B 《Science (New York, N.Y.)》2003,301(5638):1387-1391

Both dauer formation (a stage of developmental arrest) and adult life-span in Caenorhabditis elegans are negatively regulated by insulin-like signaling, but little is known about cellular pathways that mediate these processes. Autophagy, through the sequestration and delivery of cargo to the lysosomes, is the major route for degrading long-lived proteins and cytoplasmic organelles in eukaryotic cells. Using nematodes with a loss-of-function mutation in the insulin-like signaling pathway, we show that bec-1, the C. elegans ortholog of the yeast and mammalian autophagy gene APG6/VPS30/beclin1, is essential for normal dauer morphogenesis and life-span extension. Dauer formation is associated with increased autophagy and also requires C. elegans orthologs of the yeast autophagy genes APG1, APG7, APG8, and AUT10. Thus, autophagy is a cellular pathway essential for dauer development and life-span extension in C. elegans.  相似文献   

Sirtuin 2 inhibitors rescue alpha-synuclein-mediated toxicity in models of Parkinson's disease     

Outeiro TF  Kontopoulos E  Altmann SM  Kufareva I  Strathearn KE  Amore AM  Volk CB  Maxwell MM  Rochet JC  McLean PJ  Young AB  Abagyan R  Feany MB  Hyman BT  Kazantsev AG 《Science (New York, N.Y.)》2007,317(5837):516-519

The sirtuins are members of the histone deacetylase family of proteins that participate in a variety of cellular functions and play a role in aging. We identified a potent inhibitor of sirtuin 2 (SIRT2) and found that inhibition of SIRT2 rescued alpha-synuclein toxicity and modified inclusion morphology in a cellular model of Parkinson's disease. Genetic inhibition of SIRT2 via small interfering RNA similarly rescued alpha-synuclein toxicity. Furthermore, the inhibitors protected against dopaminergic cell death both in vitro and in a Drosophila model of Parkinson's disease. The results suggest a link between neurodegeneration and aging.  相似文献   

Initiating and cancer-propagating cells in TEL-AML1-associated childhood leukemia     

Hong D  Gupta R  Ancliff P  Atzberger A  Brown J  Soneji S  Green J  Colman S  Piacibello W  Buckle V  Tsuzuki S  Greaves M  Enver T 《Science (New York, N.Y.)》2008,319(5861):336-339

Understanding cancer pathogenesis requires knowledge of not only the specific contributory genetic mutations but also the cellular framework in which they arise and function. Here we explore the clonal evolution of a form of childhood precursor-B cell acute lymphoblastic leukemia that is characterized by a chromosomal translocation generating a TEL-AML1 fusion gene. We identify a cell compartment in leukemic children that can propagate leukemia when transplanted in mice. By studying a monochorionic twin pair, one preleukemic and one with frank leukemia, we establish the lineal relationship between these "cancer-propagating" cells and the preleukemic cell in which the TEL-AML1 fusion first arises or has functional impact. Analysis of TEL-AML1-transduced cord blood cells suggests that TEL-AML1 functions as a first-hit mutation by endowing this preleukemic cell with altered self-renewal and survival properties.  相似文献   

The relationship of soil province to molecular characterization and phylogenetic analysis of Cryptosporidium parvum isolated from calves in Georgia     

Miller DL  Mauel MJ  Liggett A  Hines ME  Frazier KS  Pence M  Whittington L  Baldwin CA 《Veterinary journal (London, England : 1997)》2006,171(3):478-482

Although Cryptosporidium spp. are found throughout the world and in multiple environmental conditions, few data are available that explore the possibility of an association between specific environmental parameters and the species or strain of Cryptosporidium. This study examines the potential association between a particular Cryptosporidium species/strain found in calves and soil provinces in Georgia, USA. Necropsy cases spanning the years 1996-2002 were tested. No significant differences (P=0.962, chi(2) test of homogeneity) between numbers of positive cases were noted among soil provinces. Phylogenetic analysis of the sequences for the PCR products revealed sequence similarity of the products with Cryptosporidium parvum strain C1. Although, clinical Cryptosporidiosis in calves was not found to be affected by soil province and may be caused by a single genotype, other genotypes may be responsible for subclinical infection and warrant further investigation.  相似文献   

One-time transfers of cash or capital have long-lasting effects on microenterprises in Sri Lanka     

de Mel S  McKenzie D  Woodruff C 《Science (New York, N.Y.)》2012,335(6071):962-966

Standard economic theory suggests that one-time business grants can have at most temporary effects, and accordingly, policies to increase incomes of the self-employed in developing countries typically rely on sustained engagement. In contrast, we found long-lasting impacts from one-time grants given in a randomized experiment to subsistence firms. Five years after we gave $100 or $200 to 115 of 197 male and 100 of 190 female Sri Lankan microenterprise owners, we found 10-percentage-point-higher enterprise survival rates, and $8-to-$12-per-month-higher profits for male-owned businesses that received the grants. Female-owned businesses showed no long-term (or short-term) impacts. Our follow-up investigation interviewed 94% of the original sample and collected survivorship data from the remaining 6%, demonstrating that tracking long-term outcomes is both feasible and worthwhile. The results suggest that one-off grants may have lasting impacts on some types of subsistence firms, challenging the view that sustained engagement is always required.  相似文献