A long-term study in Merino sheep experimentally infected with Mycobacterium avium subsp paratuberculosis: clinical disease, faecal culture and immunological studies

Two longitudinal experiments involving Merino sheep challenged with either bovine or ovine strains of Mycobacterium avium subsp. paratuberculosis (Map) have been conducted over a period of 54 and 35 months, respectively. Blood samples for the interferon-gamma test, the absorbed ELISA and faecal samples for bacteriological culture were taken pre-challenge and monthly post-challenge. Infections were induced with either a bovine or ovine strain of Map in separate experiments with infections being more easily established, in terms of faecal bacterial shedding and clinical disease when the challenge inoculum was prepared from gut mucosal tissue than cultured bacteria. The patterns of response for shedding and clinical disease were similar. Cell-mediated immune responses were proportionally elevated by at least an order of magnitude in all sheep dosed with either a bovine or ovine strain of Map. Conversely, antibody responses were only elevated in a relatively small proportion of infected sheep. Neither of the clinically affected tissue challenged sheep developed an antibody response despite the presence of persistent shedding and the development and decline in cell-mediated immunity. The results indicated that for sheep the interferon-gamma test may be useful for determining if a flock has been exposed to ovine Johne's disease. (C) 2004 Elsevier B.V. All rights reserved.

Experiments and modelling of phenanthrene biodegradation in the aqueous phase by a mixed culture

Pollution by polycyclic aromatic hydrocarbons(PAHs) is widespread due to unsuitable disposal of industrial waste. They are mostly defined as priority pollutants by environmental protection authorities worldwide. Phenanthrene, a typical PAH, was selected as the target in this paper. The PAH-degrading mixed culture, named ZM, was collected from a petroleum contaminated river bed. This culture was injected into phenanthrene solutions at different concentrations to quantify the biodegradation process. Results show near-complete removal of phenanthrene in three days of biodegradation if the initial phenanthrene concentration is low. When the initial concentration is high, the removal rate is increased but 20%-40% of the phenanthrene remains at the end of the experiment. The biomass shows a peak on the third day due to the combined effects of microbial growth and decay. Another peak is evident for cases with a high initial concentration, possibly due to production of an intermediate metabolite. The pH generally decreased during biodegradation because of the production of organic acid. Two phenomenological models were designed to simulate the phenanthrene biodegradation and biomass growth. A relatively simple model that does not consider the intermediate metabolite and its inhibition of phenanthrene biodegradation cannot fit the observed data. A modified Monod model that considered an intermediate metabolite (organic acid) and its inhibiting reversal effect reasonably depicts the experimental results.

A long-term study in Angora goats experimentally infected with Mycobacterium avium subsp paratuberculosis: Clinical disease, faecal culture and immunological studies

Two longitudinal experiments involving Angora goats challenged with either bovine or ovine strains of Mycobacterium avium subspecies paratuberculosis (Map) have been conducted over a period of 54 and 35 months, respectively. Blood samples for the interferon-gamma (IFN-gamma) test and the absorbed ELISA and faecal samples for bacteriological culture were taken pre-challenge and monthly post-challenge. Persistent shedding, IFN-gamma production, seroconversion and clinical disease occurred earlier with the bovine Map gut mucosal tissue challenge inoculum than with cultured bacteria. The IFN-gamma responses of the gut mucosal tissue and bacterial challenge groups were substantially and consistently higher than those of the control group. The in vivo and cultured cattle strains were much more pathogenic for goats than the sheep strains with persistent faecal shedding, seroconversion and clinical disease occurring in the majority of bovine Map challenged goats. With the ovine Map, 3 goats developed persistent antibody responses but only one of these goats developed persistent faecal shedding and clinical disease. However, there was no significant difference between the IFN-gamma responses of the tissue challenged, bacterial challenged and control groups. Compared with sheep, the ELISA appeared to have higher sensitivity and the IFN-gamma test lower specificity. (C) 2005 Elsevier B.V. All rights reserved.

The kinetics of baculovirus adsorption to insect cells in suspension culture

The influence of various culture parameters on the attachment of a recombinant baculovirus to suspended insect cells was examined under normal culture conditions. These parameters included cell density, multiplicity of infection, and composition of the cell growth medium. It was found that the fractional rate of virus attachment was independent of the multiplicity of infection but dependent on the cell density. A first order mathematical model was used to simulate the adsorption kinetics and predict the efficiency of virus attachment under the various culture conditions. This calculated efficiency of virus attachment was observed to decrease at high cell densities, which was attributed to cell clumping. It was also observed that virus attachment was more efficient in Sf900II serum free medium than it was in IPL-41 serum-supplemented medium. This effect was attributed to the protein in serum which may coat the cells and so inhibit adsorption. A general discussion relating the observations made in-these experiments to the kinetics of recombinant baculovirus adsorption to suspended insect cells is presented.

Can occupational therapy intervention play a part in maintaining independence and quality of life in older people? A randomised controlled trial Jeannine Liddle 1 , 2 , Lyn March 3 , Barbara Carfrae 4 , Terence Finnegan 5 , Jane Druce 6 , Jennifer Schwarz 7 Peter Brooks

The main objective of this study was to see if older people could maintain their quality of life and independence after their homes had been modified and they were using community services as recommended by an occupational therapist. There were 167 study participants aged 69 to 94 years from the Northern Sydney Area, After being assessed at home by an occupational therapist, 105 were randomly allocated to one of two groups, to either have or not have the occupational therapist's recommendations carried out, They were assessed again after six months, A third group did not require any intervention, This group was followed up by telephone and postal questionnaire at six months. The main outcome measures used were the Sickness Impact Profile, the Philadelphia Geriatric Center Morale Scale, the Life Satisfaction Index, assessment of Activities of Daily Living, the Health Assessment Questionnaire and change in residence. After six months there were no difference in outcomes among the three groups. Most study participants remained at a satisfactory level on each measure. Three people had died, One had moved to hostel care and one had moved to a nursing home. A further 14 from the group having no intervention had withdrawn from the study, A secondary objective of this study was to indicate the responsiveness of these outcome measures to change in the short term (over six months) in an elderly population. Twelve-month assessments are in progress and may indicate what to expect from these outcome measures in the medium term.