Evaluation of vaccination with a commercial subunit vaccine on shedding of Salmonella enterica in subclinically infected dairy cows

OBJECTIVE: To estimate the efficacy of a commercially available Salmonella enterica subunit vaccine on the subclinical shedding of S enterica in dairy cattle. DESIGN: Randomized, controlled trial. ANIMALS: 175 mature cows on 2 dairy farms with a history of S enterica infection. PROCEDURES: 25% of the mature cows from each herd were systematically randomized to receive an S enterica subunit vaccine following label guidelines. The remaining 75% of cows in each herd served as nonvaccinated controls. Fecal samples were collected from all cows at the time of initial vaccination (day 0), booster vaccination (day 14), 2 weeks following the booster vaccination (day 28), and 10 weeks following the start of the trial (day 70). All samples were processed on the day of collection and cultured for S enterica. RESULTS: 651 fecal samples were obtained over the entire study period. Salmonella enterica was recovered from 46 (7.1%) of the samples. Shedding of S enterica was similar for vaccinated and nonvaccinated control cows on each of the collection dates. CONCLUSIONS AND CLINICAL RELEVANCE: The study revealed no evidence that extralabel vaccination with a commercial subunit S enterica vaccine reduced shedding of S enterica in subclinically infected dairy cows in these herds.     

Ein Tiefbohrgerät zur Ermittlung des Einflusses verschiedener Formen der Landbewirtschaftung auf den Nitrateintrag in tiefere Bodenschichten

A new, efficient auger technique for sampling soil cores from deep soil layers to study the effects of different farm management systems upon nitrate leaching into ground water In order to study the effects of different farm management systems upon nitrate leaching into ground water, soil analysis has to be extended from the root zone to deeper soil layers. In the past, a major obstruction for carrying out such analysis was the lack of equipment which enables the taking of great numbers of soil samples in a short time without heavy physical effort. The instrumental setup presented here fulfills these requirements. Further advantages of this machine are its low weight and the possibility of sampling to a depth of 20 m. Exemplary results of one test site in Lower Bavaria on a loess soil are presented. It has been found that N-balance, duration of leaching period and seepage rate are main factors of the polyfactorial process of formation and downward movement of nitrate bands. Depending on the annual seepage rate the speed of nitrate transport in loess is extremely variable. From January 1986 to January 1987 the nitrate bands moved downwards by 0.7 m; from January 1987 to June 1988 they were transported by about 2.5m.     

Mitogenic influence of human R-spondin1 on the intestinal epithelium

Several described growth factors influence the proliferation and regeneration of the intestinal epithelium. Using a transgenic mouse model, we identified a human gene, R-spondin1, with potent and specific proliferative effects on intestinal crypt cells. Human R-spondin1 (hRSpo1) is a thrombospondin domain-containing protein expressed in enteroendocrine cells as well as in epithelial cells in various tissues. Upon injection into mice, the protein induced rapid onset of crypt cell proliferation involving beta-catenin stabilization, possibly by a process that is distinct from the canonical Wnt-mediated signaling pathway. The protein also displayed efficacy in a model of chemotherapy-induced intestinal mucositis and may have therapeutic application in gastrointestinal diseases.     

A new population of very high energy gamma-ray sources in the Milky Way

Very high energy gamma-rays probe the long-standing mystery of the origin of cosmic rays. Produced in the interactions of accelerated particles in astrophysical objects, they can be used to image cosmic particle accelerators. A first sensitive survey of the inner part of the Milky Way with the High Energy Stereoscopic System (HESS) reveals a population of eight previously unknown firmly detected sources of very high energy gamma-rays. At least two have no known radio or x-ray counterpart and may be representative of a new class of "dark" nucleonic cosmic ray sources.