Tumour Progression and Spontaneous Regression in the Lewis Rat Sarcoma Model.

Spontaneous regression of tumours is a fascinating phenomenon rarely observed in oncological patients. We used a Lewis rat sarcoma model in which subcutaneous tumours developed after inoculation of the R5-28/clone C4 cells. Rats with tumour progression showed splenomegaly and anaemia. Tumour growth was associated with leucocytosis, granulocytosis, decrease in lymphocyte and CD161(+) population in peripheral blood and increase in serum MCP1 concentration. Animals with spontaneous regression of tumours initially showed an increase in white blood cells number and proportion of granulocytes. Between the 42nd and 49th day, however, values of these parameters dropped in correlation with reduction of tumour size. In spontaneously regressed tumours, vascularization was higher and on the contrary, progressive tumours had more necrotic areas with a high number of infiltrating granulocytes. In conclusion, progression and spontaneous regression of tumours in the Lewis rat sarcoma model is associated with distinct changes in populations of blood cells and immune cells which participate in these completely different processes of tumourigenesis.

Cortisol and secretory immunoglobulin A response to stress in German shepherd dogs.

The aim of the study was to determine whether cortisol and secretory Immunoglobulin A (sIgA) could be used as an indicator of acute stress in both young and adult dogs. Seventeen German shepherd puppies were exposed to the Puppy test (challenge test) at the age of seven weeks. This test has been routinely used to assess the future working ability of potential police dogs. In addition, ten adult females were subjected to 4 minutes of defense training under stressful conditions. Saliva was collected from the puppies and adult females before testing and 20 minutes after the start of testing, using a cotton swab held for 1-2 minutes in each dog's mouth. Cortisol concentrations increased after the test compared to the control sample both in puppies and the adult females. However adult females showed a significant decrease in sIgA after defense training while puppies showed a tendency of increase in sIgA. We propose that salivary cortisol could be used as an indicator of stress in puppies during early ontogeny. It is not yet clear whether sIgA could be used as a useful indicator of short-term stress in dogs.

Bifidobacterium animalis subsp. lactis strains isolated from dog faeces.

The aim of the study was to identify and characterize dog bifidobacterial isolates and compare them with commercial probiotic strains. Sixteen isolates of Bifidobacterium animalis ssp. lactis from dog faeces (German Shepherd Dog) were identified by subspecies-specific PCR, MALDI-TOF MS and sequencing. This study is the first describing B. animalis ssp. lactis occurring within the intestinal tract of dogs. Our dog isolates showed slightly different fingerprinting profiles obtained by RAPD-PCR and REP-PCR from those isolated from yogurt and type strains of B. animalis ssp. lactis. Both, dog and yogurt origin strains indicated survival in the simulated in vitro digestion assay and were resistant to low pH and bile salts. Moreover, strong auto-aggregation activity was observed only in dog origin B. animalis ssp. lactis strains. Dog strains showed good properties predicting their survival ability in GIT and could be tested as a potential new probiotics for dogs or other hosts.

High seroprevalence of granulocytic ehrlichiosis distinguishes sheep that were the source of an alimentary epidemic of tick-borne encephalitis.

A sheep herd from which contaminated cheese was produced, causing 21 cases of alimentary tick-borne encephalitis (TBE) in human beings, was tested serologically for the presence of specific antibodies against both the TBE virus (TBEV) and Anaplasma phagocytophilum, the cause of tick-borne fever (TBF) in ruminants, and compared with three other herds variously exposed to tick bites but without any TBE history. Virus-neutralisation (VN) with the TBEV strain Hypr and CV-1 cells was used in TBE tests, and indirect immunofluorescence assay (IFA) with neutrophils from goats experimentally infected with A. phagocytophilum was used for TBF testing. In 13 sheep from the incriminated herd (N =41), VN titres ranging from 1/4 to 1/128 traced previous TBE infection and all sheep had elevated titres of A. phagocytophilum antibodies ranging from 1/80 to 1/5120 in IFA, whereas two other herds (N = 8 and 9) were seronegative for TBEV and had significantly lower levels of A. phagocytophilum antibodies, corresponding to a lesser challenge from TBF. A control herd (N = 10) that was grazed on tick-free meadows in north Norway was completely seronegative. The respective distributions of positive titres of A. phagocytophilum and TBEV antibodies in the incriminated herd were not mutually random; the animals with higher anti-A. phagocytophilum titres tended to have lower anti-TBEV titres and vice versa (Spearman correlation coeff. =-0.86, p< or =0.01). The authors hypothesize that the immunosuppressive effect of TBF co-infection in sheep could be a contributory cause of TBE-virus contamination of milk, an aspect of TBE epidemiology that has not been considered thus far.