Sensitivity and specificity of serological tests for infectious bronchitis virus antibodies in broilers.

Broilers with maternally-derived immunity (MDI) to infectious bronchitis (IB) were either spray-vaccinated with H120 at 1 day old, or not vaccinated, then challenged at 28 days with one of four different IBV serotypes. Birds were bled frequently and the sera tested by agar gel precipitation (AGP), haemagglutination inhibition (HI), 2 commercial ELISAs, and virus neutralization (VN) to compare the sensitivity and specificity of the assays. The AGP detected a transient response to challenge with a specificity of 100% and a sensitivity of approximately 40%. The ELISAs showed moderate sensitivity and high specificity with sera from non-vaccinated broilers, and high sensitivity and variable specificity with vaccinated birds. Depending on the cut-off value used, the specificity of HI tests was 55 to 100%, while the sensitivity varied widely, making identification of the serotype of an IB challenge unreliable. In vaccinated broilers the sensitivity of the VN tests (used at 21 days post-challenge only) varied from 20 to 100%, while the specificity was dependant on the cut-off value selected. Increases in HI, VN and ELISA titres in vaccinates were generally about half those in non-vaccinates. It is concluded that AGP and ELISA are adequate to detect antibody responses to IBV challenge in both vaccinated and non-vaccinated broilers. In the ELISA, a cut-off value higher than that suggested by the manufacturers is preferred in vaccinated broilers. Similarly, a cut-off value of at least log(2)7 is desirable when attempting to use HI for IB serotyping.     

Selection of Self-reactive Peptides Within Human Aggrecan by use of a HLA-DRB1*0401 Peptide Binding Motif

The pathogenesis of joint destruction in rheumatoid arthritis remains ill-defined. Joint destruction is thought to be the result of tissue damage mediated by T cells. The mere presence of articular cartilage appears responsible for sustaining chronic synovitis and thereby forwards a role for cartilage-responsive T cells in RA. Taking advantage of the positive DRB1*0401 association with RA susceptibility, we reasoned that T-cell recognition of autoantigens in RA would be restricted by DRB1*0401-encoded molecules. A DR4 (B1*0401) peptide binding motif was used for the identification of putative T-cell epitopes within human aggrecan, a candidate autoantigen. Thirteen peptides were synthesized and tested for binding DRB1*0401 or 0404-encoded molecules. Selected binders were tested for induction of pro-liferative responses in peripheral blood mononuclear cells from donors carrying the DR4 or DR1 specificity. Both healthy and RA donors responded to human aggrecan-derived peptides, thereby identifying these sequences as T-cell epitopes. Interestingly, responses to aggrecan-derived epitopes were significantly decreased in RA patients compared to controls. This was not due to an overall hyporesponsiveness of RA patients since responses to a recall antigen or mitogen did not differ from controls. The data suggest that in RA, aggrecan-specific T cells may exist in a different stage of activation or may have left the periphery to home to the joint.     

Intestinal absorption of human insulin in pigs using delivery systems based on superporous hydrogel polymers

The interaction of 8-methoxypsoralen (8-MOP) with calf thymus DNA was studied in darkness at 25 degrees C and pH 7.4. The enthalpy curve for 8-MOP-DNA interaction was obtained by isothermal titration calorimetry and showed a two-step process for the interaction. According to the spectrophotometric data, it was suggested that some compaction may occur in the DNA structure at higher [8-MOP](t)/[DNA] ratio. Using the fluorescence quenching data, the Scatchard analysis was performed for 8-MOP-DNA interaction at the extended ranges of drug concentration. The results indicated that the first set of binding sites was occupied by 1 mol of drug bound per near eight base pairs of DNA. Also 8-MOP caused the quenching of the fluorescence emission of DNA-ethidium bromide complex. The Scatchard analysis of these data indicated the non-competitive manner for quenching. A non-displacement based quenching mechanism has been suggested for this behavior. The circular dichroism spectra also confirmed the non-intercalative binding of 8-MOP at higher concentrations accompanied by some conformational changes in DNA structure. It has been suggested that at low drug load, 8-MOP binds to DNA as an intercalator, which is an endothermic process, whereas at higher ratios of [8-MOP](t)/[DNA], it binds to the outside of DNA, probably in the minor groove and causes some compaction in DNA, which is the exothermic process.     

Public health impact of community-based nutrition and lifestyle interventions

Community-based interventions have increasingly received attention since researchers and public health professionals have come to acknowledge the importance of an environment that makes the healthy choice the easy choice. All stakeholders including the target community are involved to achieve changes in legislation, in people's social and physical context, and in individual characteristics that support healthy diets and other lifestyles. Some early large-scale community-based heart health interventions showed promising results. The Stanford Five City Project, for example, showed net improvements in knowledge of coronary heart disease risk factors of approximately 12%. Net declines in smoking prevalence (14%), cholesterol (2%), and systolic (3%) and diastolic (5%) blood pressure were also observed. Most later studies did not replicate these findings and it was therefore suggested that community-based interventions, which require substantial commitment and resources, may be less effective than approaches targeting high-risk groups. We present the rationale and theories for community-based interventions, and then elaborate on the methodological challenges in the design and the outcome and process evaluation of community-based interventions. We provide an overview of some of the evidence on the effectiveness of community-based heart health interventions and conclude with the perspectives for community-based interventions in future research and practice.     

The power of communication. Modifying behaviour: effectively influencing nutrition patterns of patients

Every year 7000 people die from obesity and another 13,000 people die by wrong diets in The Netherlands. Part of this problem can be solved when the communication between general practitioners (GPs) and patients about nutrition and diets improves. There are four activities that can contribute greatly to the communication between GPs and their patients. (1) GPs can ask nonjudgemental questions that help to understand their patients' perspective on the illness, its causes and possible treatments. (2) GPs can listen carefully to their patients' replies and try to pick up clues to their understanding as well as their ability to adhere to a recommended treatment. (3) GPs can work with patients and family members to set realistic and achievable goals for behavioural change. (4) GPs can involve their patients in active problem solving. The role that practitioners play in changing patients' behaviour to healthy lifestyles is more similar to a coach. They should be along the sideline, empowering patients, helping them develop their own healthy lifestyles. When GPs apply these principles in daily practice, they will find out that they can effectively influence the nutrition patterns of their patients.     

Effects of Enrofloxacin on Porcine Phagocytic Function

The interaction between enrofloxacin and porcine phagocytes was studied with clinically relevant concentrations of enrofloxacin. Enrofloxacin accumulated in phagocytes, with cellular concentration/extracellular concentration ratios of 9 for polymorphonuclear leukocytes (PMNs) and 5 for alveolar macrophages (AMs). Cells with accumulated enrofloxacin brought into enrofloxacin-free medium released approximately 80% (AMs) to 90% (PMNs) of their enrofloxacin within the first 10 min, after which no further release was seen. Enrofloxacin affected neither the viability of PMNs and AMs nor the chemotaxis of PMNs at concentrations ranging from 0 to 10 microg/ml. Enrofloxacin (0.5 microg/ml) did not alter the capability of PMNs and AMs to phagocytize fluorescent microparticles or Actinobacillus pleuropneumoniae, Pasteurella multocida, and Staphylococcus aureus. Significant differences in intracellular killing were seen with enrofloxacin at 5x the MIC compared with that for controls not treated with enrofloxacin. PMNs killed all S. aureus isolates in 3 h with or without enrofloxacin. Intracellular S. aureus isolates in AMs were less susceptible than extracellular S. aureus isolates to the bactericidal effect of enrofloxacin. P. multocida was not phagocytosed by PMNs. AMs did not kill P. multocida, and similar intra- and extracellular reductions of P. multocida isolates by enrofloxacin were found. Intraphagocytic killing of A. pleuropneumoniae was significantly enhanced by enrofloxacin at 5x the MIC in both PMNs and AMs. AMs are very susceptible to the A. pleuropneumoniae cytotoxin. This suggests that in serologically naive pigs the enhancing effect of enrofloxacin on the bactericidal action of PMNs may have clinical relevance.