Field trial of a synthetic tsetse-repellent technology developed for the control of bovine trypanosomosis in Kenya   总被引：1，自引：0，他引：1  

Bett B  Randolph TF  Irungu P  Nyamwaro SO  Kitala P  Gathuma J  Grace D  Vale G  Hargrove J  McDermott J 《Preventive veterinary medicine》2010,97(3-4):220-227

We conducted a field trial among Maasai cattle-keepers in Nkuruman and Nkineji areas of Kenya to evaluate the effectiveness of a synthetic tsetse-repellent technology developed for the control of trypanosomosis in cattle. The technology was a repellent (2-methoxy 4-methylphenol) emitted from dispensers attached to collars worn by cattle. Treatment was allocated at the herd level to ensure adequate protection of all the animals in a herd, with measurements of effectiveness conducted at the individual-animal level. The trial began in April 2005 and ran for 16 months including a baseline phase of 4 months. We recruited 12 herds in each area using a restricted random-sampling technique and distributed them equally into intervention (repellent) and control groups. Sample size was determined using a formal power calculation. Effectiveness or minimal worthwhile difference was defined as a 50% reduction in the incidence of trypanosome infection in the treated versus control group (effectiveness below which the technology was considered by experts as not viable compared to existing control techniques). All the animals in the recruited herds were screened monthly (buffy-coat technique) for trypanosome infections. The analysis followed the principle of intention-to-treat by which subjects are analysed according to their initial treatment assignment, regardless of the mechanical performance of the device. Crude and adjusted effects of the technology were 23% (p<0.001) and 18% (p=0.08) reduction in the infection incidence in the treatment compared to the control groups, respectively. The impact of the technology estimated in this study did not achieve the threshold of 50% reduction in the trypanosome infection incidence set a priori to indicate effectiveness (p<0.001). We therefore concluded that the prototype repellent technology package was not sufficiently effective in reducing trypanosome infection incidence under natural tsetse challenge to merit commercial development.  相似文献   

Transfection of chicken embryo fibroblasts with Marek's disease virus DNA   总被引：11，自引：0，他引：11  

R W Morgan  J L Cantello  C H McDermott 《Avian diseases》1990,34(2):345-351

Total DNA from Marek's disease virus (MDV)-infected chicken embryo fibroblasts was transfected into freshly plated secondary chicken embryo fibroblasts using calcium phosphate-mediated transfection. Transfection frequencies were dose-dependent and non-linear. The maximum transfection frequencies of nine MDV DNA preparations using 8-25 micrograms total DNA ranged from 45 to 898 plaques per calcium phosphate/DNA precipitate. Approximately 100-200 plaques per 60-mm tissue-culture dish using 1-5 micrograms total DNA from MDV-infected chicken embryo fibroblasts were typically obtained. Transfection was most efficient when the pH of the HEPES buffer was 7.0, no additional carrier DNA was added to the precipitates, and the cultures were exposed for 3 minutes to 15% buffered glycerol 4 hours after the addition of the calcium phosphate/DNA precipitates.  相似文献   

Rapid progression to AIDS in HIV+ individuals with a structural variant of the chemokine receptor CX3CR1     

Faure S  Meyer L  Costagliola D  Vaneensberghe C  Genin E  Autran B  Delfraissy JF  McDermott DH  Murphy PM  Debré P  Théodorou I  Combadière C 《Science (New York, N.Y.)》2000,287(5461):2274-2277

Human immunodeficiency virus (HIV) enters cells in vitro via CD4 and a coreceptor. Which of 15 known coreceptors are important in vivo is poorly defined but may be inferred from disease-modifying mutations, as for CCR5. Here two single nucleotide polymorphisms are described in Caucasians in CX3CR1, an HIV coreceptor and leukocyte chemotactic/adhesion receptor for the chemokine fractalkine. HIV-infected patients homozygous for CX3CR1-I249 M280, a variant haplotype affecting two amino acids (isoleucine-249 and methionine-280), progressed to AIDS more rapidly than those with other haplotypes. Functional CX3CR1 analysis showed that fractalkine binding is reduced among patients homozygous for this particular haplotype. Thus, CX3CR1-I249 M280 is a recessive genetic risk factor in HIV/AIDS.  相似文献   

A comparison of different models for assessing variations in the sero-prevalence of infectious bovine rhinotracheitis by farm, area and district in Kenya     

J. J. McDermott  M. Kadohira  C. J. O'Callaghan  M. M. Shoukri 《Preventive veterinary medicine》1997,32(3-4):219-234

The relative variability of the sero-prevalence of antibodies to infectious bovine rhinotracheitis (IBR) due to cow, farm, and agroecological area levels were investigated for three contrasting districts in Kenya: Samburu, an arid and pastoral area; Kiambu, a tropical highland area; and Kilifi, a typical tropical coastal area. Cattle were selected by two-stage cluster sampling and visited once between August 1991 and 1992. Data on animal, farm, and area factors were analyzed using Schall's algorithm and MLn (multi-level, n-level), two generalized mixed-model programs suitable for multi-level analysis. Most variation in IBR sero-prevalence was from farm-to-furm. This was reflected by the many farm-level fixed effects (farm size, disease control measures and type of breeding) significant in models both ignoring and accounting for single variance components (clustering) at farm, area, and district levels. Area-to-area and district-to-district variations were noted but the area and district variance components were one-third and one-fifth the size of the farm variance components for both methods. As farm-to-farm variation differed markedly by farm size and district, models in MLn were extended to allow for multiple farm-level variance components by these categories. For each, sero-prevalence of IBR increased with age and was significantly decreased on small-sized zero-grazing farms. These models, particularly the model with different farm variance components by districts, fit the data better and highlighted well that there was considerable farm-to-farm variation—differing by district—and that the available farm-level fixed effects did not predict IBR sero-prevalence well.  相似文献   

A molecular basis for MHC class II--associated autoimmunity   总被引：52，自引：0，他引：52  

J A Todd  H Acha-Orbea  J I Bell  N Chao  Z Fronek  C O Jacob  M McDermott  A A Sinha  L Timmerman  L Steinman 《Science (New York, N.Y.)》1988,240(4855):1003-1009

Class II major histocompatibility (MHC) molecules have an immunoregulatory role. These cell-surface glycoproteins present fragments of protein antigens (or peptides) to thymus-derived lymphocytes (T cells). Nucleotide sequence polymorphism in the genes that encode the class II MHC products determines the specificity of the immune response and is correlated with the development of autoimmune diseases. This study identifies certain class II polymorphic amino acid residues that are strongly associated with susceptibility to insulin-dependent diabetes mellitus, rheumatoid arthritis, and pemphigus vulgaris. These findings implicate particular class II MHC isotypes in susceptibility to each disease and suggest new prophylactic and therapeutic strategies.  相似文献   

FLASHING OF FIREFLIES     

McDermott FA 《Science (New York, N.Y.)》1916,44(1139):610-611

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