Haemagglutinating and adhesive activity of Bordetella bronchiseptica treated with sub-minimal inhibitory concentrations of gentamicin.

The effect of sub-minimal inhibitory concentrations of gentamicin on the haemagglutinating activity of Bordetella bronchiseptica was studied. Gentamicin exerted dissimilar effect on the production of haemagglutinin to calf and dog erythrocytes. The drug significantly reduced the haemagglutinating titres of calf-negative strains with dog red blood cells while it caused only a slight decrease in the haemagglutinating titres of calf-positive strains with bovine erythrocytes. The results support the view that bovine haemagglutinin is an adhesin of B. bronchiseptica.     

Functional restoration of the bursa of Fabricius following in ovo infectious bursal disease vaccination

The primary role of the avian bursa of Fabricius is to provide an essential microenvironment for B-lymphocytes to diversify their immunoglobulin genes by gene hyperconversion. Infectious bursal disease (IBD) vaccination using intermediate plus vaccine strains can temporarily deplete the bursal follicles and interrupt the normal B-cell development, which is generally followed by B-cell repopulation and histological regeneration. To find evidence that functional restoration of the bursa of Fabricius occurs in addition to the histological regeneration, we have analysed the chB1 gene expression, which indicates active bursal B-lymphocytes, and also the surface expression of a carbohydrate structure Lewis(x), a marker which identifies those bursal B-lymphocytes that are undergoing gene hyperconversion. In ovo vaccination with an immune complex vaccine (IBDV-BDA) caused transient bursal destruction in both the SPF and the maternally protected broiler groups with differences evident in the starting time, the severity and the duration of the effect. After the depletion phase, signs of histological regeneration appeared together with chB1- and Lewis(x) expression indicating that B-lymphocytes were functionally active and the bursa of Fabricius was serving again as an efficient primary lymphoid organ providing an appropriate microenvironment for B-cell development.     

Haematological and biochemical findings in cats in Australia with lymphosarcoma

OBJECTIVE: To describe, for the first time, haematological and serum biochemical findings in cases of lymphosarcoma in Australian cats. DESIGN: A prospective multi-institutional study. PROCEDURE: Of 118 affected cats presented to the authors over a 18-month period, 97 were evaluated haematologically and 87 biochemically. Haematological analysis usually included determination of packed cell volume, haemoglobin concentration, red blood cell and leukocyte counts, differential leukcocyte count, reticulocyte count and examination of buffycoat smears for neoplastic cells. Serum biochemical analysis was done primarily with a discrete analyser and included a panel of commonly used analytes. RESULTS: Nonregenerative anaemia was present in 54% (52/97) of cats. Neutrophilia, present in 65% (59/91) of cats, was commonly associated with lymphocytopaenia, eosinopaenia and monocytosis. Of the 13 cats with a secondary leukaemic manifestation, only five had distinct lymphocytosis. Serum biochemical abnormalities either were nonspecific, such as hypoglycaemia in 37% (32/87) of cats, or related to specific tissue involvement, such as hypoalbuminaemia in 76% (31/41) of cats with alimentary involvement and azotaemia in 60% (15/25) of cats with renal involvement. CONCLUSION: It was shown for the first time that haematological and serum biochemical findings are of limited value in diagnosing lymphosarcoma in Australian cats, except if they are leukaemic. Although clinical pathological changes were common, they were nonspecific or related to specific tissue involvement. Their value in assessing response to therapy needs to be examined further. Patient characteristics such as age, breed and sex also had limited effect on laboratory findings and those observed were of little consequence. Additionally, histological and immunophenotypical variations in tumour type had little effect on laboratory findings.     

Impact of indigenous aphids on development of the invasive common ragweed (<Emphasis Type="Italic">Ambrosia artemisiifolia</Emphasis> L.) in Hungary

The common ragweed, Ambrosia artemisiifolia is a widespread invasive weed species in Europe. In order to estimate the deteriorative effect of native arthropods on the invasive ragweed the effect of three indigenous aphid species on plant development and pollen production was studied. Common ragweed plants grown in a greenhouse were artificially infested with five apterous individuals of either Aphis fabae, Brachycaudus helichrysi or Myzus persicae at the 4-leaf stage. Feeding by all three aphid species over a 5-week period significantly reduced plant height, the number of male inflorescences, the length of racemes, pollen emission and plant dry mass. Brachycaudus helichrysi produced the largest colonies, followed by A. fabae and M. persicae. In a host plant choice test, B. helichrysi showed significant preference for ragweed over sunflower, whereas A. fabae preferred sunflower and M. persicae did not show any preference. In a field experiment, the growth rate of A. fabae on caged ragweed plants was similar to that in the greenhouse, but the final numbers of B. helichrysi and M. persicae after 30 days was ten and seven times lower than under greenhouse conditions, respectively. On exposed field plants, B. helichrysi was more abundant than other species. However, no aphid species affected the height or dry mass of either caged or exposed plants during a 30-day period. Under controlled conditions aphids effectively hampered development and pollen production of ragweed, however, under Hungarian field conditions the development of ragweed was much more dynamic, therefore no deleterious effect of aphid feeding occurred.     

Intracranial meningioma causing internal ophthalmoparesis in a dog

A 10-year-old, spayed female, Irish water spaniel was presented with a 2-week history of anisocoria characterized by mydriasis of the right eye compared to the left eye in ambient light. Ophthalmic and neurological examinations, combined with pharmacological testing, identified a disease process affecting the right parasympathetic nucleus of cranial nerve 3 (CN III) and/or the parasympathetic component of CN III. Magnetic resonance imaging (MRI) identified a mass involving the right midbrain and extending caudally to the rostral border of the medulla oblongata. The dog became comatose within 12 h following MRI and was euthanized. Histopathology identified the intracranial mass as a meningioma.