No abstract

Five QX-like infectious bronchitis virus (IBV) strains, isolated from different field outbreaks and two reference IBV strains of known serotypes (M41 and 793/B), were used in the present study to investigate and compare their pathogenicity for 1-day-old specific pathogen free chickens. The ability of the strains to inhibit trachea epithelium ciliary activity, to induce immune response, to replicate and to cause histopathological lesions in designated organs was followed by repeated samplings during a period of 42 days post infection. Clear differences in pathogenicity and in organ distribution of the three serotypes were found. Strain 793/B had the least capacity to invade the investigated organs, while it produced a good humoral response as measured by enzyme-linked immunosorbent assay. The QX-like strains generally replicated to higher titres, although differences were found among the five strains in their pathogenicity and affinity for different organs. The Chinese isolate of QX-like virus caused the most severe lesions and induced the highest antibody titres. Severe kidney damage and dilatation of the oviduct were the prominent lesions that could be related to the QX-like IBV strains, although neither marked virus replication nor histopathological lesions were detected in the oviduct.

Parvovirus infection of Muscovy ducks caused by a genetically and antigenically distinct virus has been reported from Germany, France, Israel, Hungary, some Asian countries and the USA. The pathological changes include those of degenerative skeletal muscle myopathy and myocarditis, hepatitis, sciatic neuritis and polioencephalomyelitis. In the study presented here, day-old and 3-week-old goslings and Muscovy ducks were infected experimentally with three different parvovirus strains (isolates of D-216/4 from the classical form of Derzsy's disease, D-190/3 from the enteric form of Derzsy's disease, and strain FM from the parvovirus disease of Muscovy ducks). All three parvovirus strains caused severe disease in both day-old and 3-week-old Muscovy ducks but in the goslings only the two strains of goose origin (D-216/4 and D-190/3) caused disease with high (90-100%) mortality when infection was performed at day old. Strain FM (of Muscovy duck origin) did not cause any clinical signs or pathological lesions in the goslings. In the day-old goslings and Muscovy ducks the principal pathological lesions were severe enteritis with necrosis of the epithelial cells (enterocytes) of the mucous membrane and the crypts of Lieberkühn, and the formation of intranuclear inclusion bodies. Other prominent lesions included hepatitis and atrophy (lymphocyte depletion) of the lymphoid organs (bursa of Fabricius, thymus, spleen). In goslings infected with the strain originating from the classical form of Derzsy's disease mild myocarditis was also detected. After infection at three weeks of age, growth retardation, feathering disorders, myocardial lesions (degeneration of cardiac muscle cells, lympho-histiocytic infiltration) and hepatitis were the most prominent lesions in both geese and Muscovy ducks. In addition to the lesions observed in the geese, muscle fibre degeneration, mild sciatic neuritis and polioencephalomyelitis were also observed in the Muscovy ducks infected with any of the three parvovirus strains.

Intense laser-driven proton pulses, inherently broadband and highly divergent, pose a challenge to established beamline concepts on the path to application-adapted irradiation field formation, particularly for 3D. Here we experimentally show the successful implementation of a highly efficient (50% transmission) and tuneable dual pulsed solenoid setup to generate a homogeneous (laterally and in depth) volumetric dose distribution (cylindrical volume of 5 mm diameter and depth) at a single pulse dose of 0.7 Gy via multi-energy slice selection from the broad input spectrum. The experiments were conducted at the Petawatt beam of the Dresden Laser Acceleration Source Draco and were aided by a predictive simulation model verified by proton transport studies. With the characterised beamline we investigated manipulation and matching of lateral and depth dose profiles to various desired applications and targets. Using an adapted dose profile, we performed a first proof-of-technical-concept laser-driven proton irradiation of volumetric in-vitro tumour tissue (SAS spheroids) to demonstrate concurrent operation of laser accelerator, beam shaping, dosimetry and irradiation procedure of volumetric biological samples.

The increasing use of proton radiotherapy during the last decade and the rising number of long-term survivors has given rise to a vital discussion on potential effects on normal tissue. So far, deviations from clinically applied generic RBE (relative biological effectiveness) of 1.1 were only obtained by in vitro studies, whereas indications from in vivo trials and clinical studies are rare. In the present work, wildtype zebrafish embryos (Danio rerio) were used to characterize the effects of plateau and mid-SOBP (spread-out Bragg peak) proton radiation relative to that induced by clinical MV photon beam reference. Based on embryonic survival data, RBE values of 1.13 ± 0.08 and of 1.20 ± 0.04 were determined four days after irradiations with 20 Gy plateau and SOBP protons relative to 6 MV photon beams. These RBE values were confirmed by relating the rates of embryos with morphological abnormalities for the respective radiation qualities and doses. Besides survival, the rate of spine bending, as one type of developmental abnormality, and of pericardial edema, as an example for acute radiation effects, were assessed. The results revealed that independent on radiation quality both rates increased with time approaching almost 100% at the 4th day post irradiation with doses higher than 15 Gy. To sum up, the applicability of the zebrafish embryo as a robust and simple alternative model for in vivo characterization of radiobiological effects in normal tissue was validated and the obtained RBE values are comparable to previous finding in animal trials.