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.     

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.     

Transmission of infectious bronchitis virus within vaccinated and unvaccinated groups of chickens.

The aim of this study was to determine whether vaccination against infectious bronchitis virus (IBV) reduces virus transmission, i.e. to test whether IBV transmission among vaccinated chickens is significantly reduced compared to that among unvaccinated chickens. In two vaccinated and two unvaccinated groups of SPF chickens, a standard measure for virus transmission, the reproduction ratio (R) was determined. R is defined as the average number of new infections caused by one typical infectious individual during its entire infectious period. A single vaccination by eye-drop with IBV H120 reduced the transmission of the IBV challenge virus among the vaccinated chickens (estimated R = 0.69, s.e. = 0.33) significantly (P < 0.05) compared to the transmission among the unvaccinated chickens (estimated R = 19.95, s.e. = 12.41). The possible implications for further study, including selection or development of vaccines are discussed.     

Comparison of methods for in vitro testing of susceptibility of porcine Mycoplasma species to antimicrobial agents.

The MICs of 18 antimicrobial agents used against strains of three porcine Mycoplasma species were determined by a serial broth dilution method. Twenty field strains of M. hyorhinis, ten field strains of M. hyopneumoniae, six field strains of M. flocculare, and the type strains of these species were tested. Twelve field strains and the type strain of M. hyorhinis were also tested by an agar dilution method. Tests were read at various time points. When the broth dilution method was used, the final MIC had to be read 2 days after color changes had stopped. MICs of tetracycline, oxytetracycline, doxycycline, and minocycline were low for the three Mycoplasma species tested. MICs of chlortetracycline were 8 to 16 times higher than MICs of the other tetracyclines. Spiramycin, tylosin, kitasamycin, spectinomycin, tiamulin, lincomycin, and clindamycin were effective against all strains of M. hyorhinis and M. hyopneumoniae. The quinolones were highly effective against M. hyopneumoniae but less effective against M. hyorhinis. The susceptibility patterns for M. hyopneumoniae and M. flocculare were similar.     

Peroxisomal Disorders: A Review on Cerebellar Pathologies

Peroxisomes are organelles with diverse metabolic tasks including essential roles in lipid metabolism. They are of utmost importance for the normal functioning of the nervous system as most peroxisomal disorders are accompanied with neurological symptoms. Remarkably, the cerebellum exquisitely depends on intact peroxisomal function both during development and adulthood. In this review, we cover all aspects of cerebellar pathology that were reported in peroxisome biogenesis disorders and in diseases caused by dysfunction of the peroxisomal α‐oxidation, β‐oxidation or ether lipid synthesis pathways. We also discuss the phenotypes of mouse models in which cerebellar pathologies were recapitulated and search for connections with the metabolic abnormalities. It becomes increasingly clear that besides the most severe forms of peroxisome dysfunction that are associated with developmental cerebellar defects, milder impairments can give rise to ataxia later in life.     

A rare cause of abdominal pain: eosinophilic gastroenteritis

Eosinophilic gastroenteritis is a disease that is characterised by an eosinophil-driven inflammation of the digestive tract, presenting with non-specific symptoms, including abdominal pain, nausea, and diarrhoea. The diagnosis is established by histopathological analysis revealing eosinophilic infiltration of the lamina propria. The disease is relatively rare but a proper diagnosis is important, since specific treatment may limit the disease severity and progression.     

LEARN 2 MOVE 7-12 years: a randomized controlled trial on the effects of a physical activity stimulation program in children with cerebral palsy

Background  

Regular participation in physical activities is important for all children to stay fit and healthy. Children with cerebral palsy have reduced levels of physical activity, compared to typically developing children. The aim of the LEARN 2 MOVE 7-12 study is to improve physical activity by means of a physical activity stimulation program, consisting of a lifestyle intervention and a fitness training program.     

LEARN 2 MOVE 0-2 years: effects of a new intervention program in infants at very high risk for cerebral palsy; a randomized controlled trial

Background

Bronchiolitis is the most common reason for admission of infants to hospital in developed countries. Fluid replacement therapy is required in about 30% of children admitted with bronchiolitis. There are currently two techniques of fluid replacement therapy that are used with the same frequency-intravenous (IV) or nasogastric (NG). The evidence to determine the optimum route of hydration therapy for infants with bronchiolitis is inadequate. This randomised trial will be the first to provide good quality evidence of whether nasogastric rehydration (NGR) offers benefits over intravenous rehydration (IVR) using the clinically relevant continuous outcome measure of duration of hospital admission.

Methods/Design

A prospective randomised multi-centre trial in Australia and New Zealand where children between 2 and 12 months of age with bronchiolitis, needing non oral fluid replacement, are randomised to receive either intravenous (IV) or nasogastric (NG) rehydration. 750 patients admitted to participating hospitals will be recruited, and will be followed daily during the admission and by telephone 1 week after discharge. Patients with chronic respiratory, cardiac, or neurological disease; choanal atresia; needing IV fluid resuscitation; needing an IV for other reasons, and those requiring CPAP or ventilation are excluded. The primary endpoint is duration of hospital admission. Secondary outcomes are complications, need for ICU admission, parental satisfaction, and an economic evaluation. Results will be analysed using t-test for continuous data, and chi squared for categorical data. Non parametric data will be log transformed.

Discussion

This trial will define the role of NGR and IVR in bronchiolitis

Trail registration

The trial is registered with the Australian and New Zealand Clinical Trials Registry - ACTRN12605000033640