Characterisation of mouse prothymocytes

In this thesis, the study of growth kinetics of thymocytes in lethally irradiated mice as a means to characterise the early T-cell progenitors is described. Normal bone marrow cells were used as the source of hemopoietic cells. The experiments show that it is possible to obtain information on T-cell differentiation from a complex experimental set-up in vivo. The quantitative relation between the thymus regeneration capacity and the CFU-S content of bone marrow cells was established. K"1netk studies of the regeneration process led to formulation of the framework for the lil vivo thymus regeneration assay (Chapter 3). From the study of erythroid and granulocyte-macrophage lineages, it had been established that at least these lineages start from early progenitor cells that are immediate successors of the pluripotent cells, but can be distinguished experimentally from CFU-S (Bol, 1980). However, apart from the cells postulated by Abramson et al. (1977), no such early progenitor cells are known for the T-cell 1"1neage. Our results obtained in thymus repopulation after transplantation of bone marrow from normal mke did not allow a distinction between the T-cell progenitor function of prothymocytes and that of the pluripotent stem cell determined as CFU-

What are probiotics? Attempts to functional definition of probiotics to improve credibility of probiotics in support of animal health

The broad and vague definitions of probiotics have resulted in high expectations and as a result thereof to disappointments in usage to cure serious diseases such as cancer, autoimmunity in humans and to improve performance in farm animals. Probiotics should not be considered as panacea

Cytokine responses in broiler lines that differ in susceptibility to malabsorption syndrome

1. Based on earlier studies it was hypothesised that there is an immunological basis for the differences in susceptibility to malabsorption syndrome (MAS). A study was conducted to investigate base-line and MAS-induced cytokine levels in the intestine of broilers that differ in MAS susceptibility. 2. The transcription of cytokine mRNA in the intestine was quantified using a real-time polymerase chain reaction (PCR) method. At different time points after disease induction the intestines of broilers were investigated for expression of interleukin (IL)-2, IL-6, IL-8, IL-18 and interferon (IFN)-?. Age-matched non-MAS-induced chickens served as controls. 3. Control chickens from a MAS-resistant line had higher concentrations of mRNA for IL-2, IL-6, IL-18 and IFN-? in the small intestine while no difference between the lines was found for IL-8. After induction of MAS the relative amounts of IL-2, IL-6, IL-8 and IFN-? mRNA increased more in the intestines of the susceptible line than in the gut of the resistant line. 4. We suggest that differences in cytokine mRNA in the base-line situation and in MAS-induced conditions indicate a difference in immune response regulation in the two broiler lines. This difference in response could lead to the difference in susceptibility to MA

Vaccinations in pig health care in the Netherlands - analysis of a questionnaire among veterinarians = Vaccinaties in de Nederlandse varkensgezondheidszorganalyse van een enquete onder dierenartsen

Veterinarians specializing in pig health care responded to a questionnaire regarding their experiences with vaccinations. The goal of the questionnaire was to gain insight into a) the reasons for vaccination and b) the factors involved in the effficacy of vaccination. The results indicated that vaccinations were typically initiated because of health problems at the farm. Veterinarians worked together with farmers and other concerned parties to initiate vaccinations. Respondents predicted that the number of vaccinations would decrease substantially with optimal farm management, but would increase if farmers were allowed (under strict conditions) to vaccinate their own pigs. The results further indicated that the nature of financial compensation predicted the rate of vaccination. Veterinarians paid according to a fixed 'fee for service' system vaccinated less frequently than did veterinarians who were paid according to an ongoing farm management contract. In conclusion, veterinarians appear to be restricted in their capacity to disseminate their experience and knowledge due to the competing needs of the farming network (animals, farmers, retailers)

Management en de weerstand van varkens = Management and the robusness of pigs

This report gives an idea of the functioning of the pig’s defence, the factors that possibly influence and the methods to measure resistanc