Studies on the toxicity of an aqueous extract of the leaves of Abrus precatorius in rats

The toxic effects of an aqueous extract of Abrus precatorius were studied in 20 male white rats over a period of 18 days. The rats were divided into four groups of five rats per group. Those in Group A served as controls while the rats in Groups B, C and D were dosed per os with 400 mg/kg, 800 mg/kg and 1 600 mg/kg of the extract, respectively. Blood samples were collected for haematological and biochemical analysis and specimens of the liver, kidney and testes were taken for histopathological studies. The study showed that the extract of A. precatorius caused decreased levels of packed cell volume, haemoglobin concentration, red blood cell count, white blood cell count, mean corpuscular volume and mean corpuscular haemoglobin. The extract also resulted in increased levels of total serum protein, albumin, alanine amino transaminase, aspartate amino transferase, alkaline phosphatase and total bilirubin. Histologically, testicular degeneration characterized by decreased numbers of lining cells of the epithelium as well as reduction in sperm cells with presence of scattered Sertoli cells were noted. The study thus showed that aqueous extract of Abrus precatorius is toxic and caution should be exercised in its use for medicinal purpose.     

In vitro generation of mature neutrophils from canine Lin- bone marrow cells

The major goal of this work was to describe the in vitro generation of mature functional neutrophils derived from a canine enriched haematopoietic progenitor cell population. We have utilised lineage depletion by immunomagnetic selection to isolate a canine haematopoietic progenitor cell population. The physical, immunological, metabolical and morphological methodologies employed in this study have permitted us to isolate and define a cell population enriched in Rh-123low and CD34+ cells. Irradiated pre-established long-term bone marrow cultures (LTBMC) were utilised to determine the self-renewal ability of lineage negative (Lin-) cells, as well as their capacity to differentiate into mature functional neutrophils. The authors demonstrate for the first time that canine neutrophils derived from Lin- cells are able to produce oxyradicals, express a specific neutrophil surface antigen, and contain gelatinase granules. These characteristics enable them to migrate through basement membranes to act as a first line defence mechanism. The fact that these cells are able to differentiate into functional mature cells, and give rise to long-term culture-initiating cells (LTC-IC) after 35 days of culture, allows the authors to assure that the isolated canine enriched haematopoietic cell population exhibit functional characteristics, associated with primitive haematopoietic cells.     

Prevalence and risk-factor analysis of Shiga toxigenic Escherichia coli in faecal samples of organically and conventionally farmed dairy cattle

Cattle are a natural reservoir for Shiga toxigenic Escherichia coli (STEC), however, no data are available on the prevalence and their possible association with organic or conventional farming practices. We have therefore studied the prevalence of STEC and specifically O157:H7 in Swiss dairy cattle by collecting faeces from approximately 500 cows from 60 farms with organic production (OP) and 60 farms with integrated (conventional) production (IP). IP farms were matched to OP farms and were comparable in terms of community, agricultural zone, and number of cows per farm. E. coli were grown overnight in an enrichment medium, followed by DNA isolation and PCR analysis using specific TaqMan assays. STEC were detected in all farms and O157:H7 were present in 25% of OP farms and 17% of IP farms. STEC were detected in 58% and O157:H7 were evidenced in 4.6% of individual faeces. Multivariate statistical analyses of over 250 parameters revealed several risk-factors for the presence of STEC and O157:H7. Risk-factors were mainly related to the potential of cross-contamination of feeds and cross-infection of cows, and age of the animals. In general, no significant differences between the two farm types concerning prevalence or risk for carrying STEC or O157:H7 were observed. Because the incidence of human disease caused by STEC in Switzerland is low, the risk that people to get infected appears to be small despite a relatively high prevalence in cattle. Nevertheless, control and prevention practices are indicated to avoid contamination of animal products.     

Comparison of steroid receptor expression in normal, dysplastic, and neoplastic canine and feline mammary tissues

Steroid receptor expression was assessed by immunohistochemistry in neoplastic, hyperplastic/dysplastic, and normal mammary tissue samples removed from 68 queens and 47 bitches, using monoclonal antibodies against human oestrogen-alpha (ER) and progesterone receptors (PR). Mammary lesions were classified according to World Health Organization (WHO) criteria, and all animals with invasive carcinomas were clinically followed for 2 years. Stromal and/or lymphatic invasion and histological grading were also recorded. In both species, ER expression was significantly higher in healthy tissues, hyperplastic/dysplastic lesions, and benign tumours than in carcinomas. The loss of ER expression was more marked in feline than in canine carcinomas. In queens, PR expression increased in dysplastic lesions and "in situ" carcinomas and decreased in invasive carcinomas, even if parts of these tumours were still PR-positive. In bitches no significant variation in PR expression was observed between normal tissue, dysplasias, and benign neoplasms, but was significantly lower in carcinomas. In both species ER and PR expression in invasive carcinomas did not correlate either with histological parameters or overall survival time. This study demonstrates several differences in steroid hormone dependency between the two species. The percentage of PR-positive feline carcinomas suggests a possible role of progesterone in promoting early tumour cell growth in queens. The low percentage of ER-positive invasive carcinomas further demonstrated the aggressive phenotype and behaviour of feline mammary tumours.     

Persistence of Salmonella Typhimurium DT120 in abattoir paddocks holding sheep

In the summer of 1999 there was an outbreak of Salmonella Typhimurium DT120 in people in the north of England which was unusual in being sensitive to antimicrobial drugs. The outbreak was linked to mutton and lamb from a local abattoir, and attention focused on four holding paddocks used to retain sheep before slaughter. In November 1999, samples of soil and faeces were taken from these paddocks and samples of faeces were taken from the concrete race leading from them. Salmonella Typhimurium was isolated from 59 of the 100 samples. Between January 2000 and October 2000 seven visits were made to the abattoir at each of which 100 samples were taken from the paddocks and concrete race and examined for the presence of Salmonella. The paddocks remained heavily contaminated with S Typhimurium DT120 until April when there was a marked reduction in the recovery of the organism. By June the contamination was minimal and by August it had disappeared, and the organism was not recovered in September or October.     

IS900 restriction fragment length polymorphism (RFLP) analysis of Mycobacterium avium subsp. paratuberculosis isolates from goats and cattle in Norway

In Norway, paratuberculosis has been frequently diagnosed in goats, while cattle have been almost free of the infection. This difference in prevalence between goats and cattle has led to speculations about the existence of a Mycobacterium avium subsp. paratuberculosis (M. a. paratuberculosis) isolate that is non-pathogenic for cattle. There is little information available on genotypic variation of M. a. paratuberculosis isolated from animals in Norway. In the present study, genotypic information on 51 isolates from goats and four isolates from cattle in Norway was obtained by use of IS900 restriction fragment length polymorphism (RFLP) analysis. All isolates from cattle and 84% of the isolates from goats had the same RFLP pattern (B-C1). Five RFLP patterns not previously detected were found. No genotypic variation that could explain a difference in host origin was found between the isolates from cattle and the majority of the Norwegian goat isolates. This lack of difference indicates that the most common M. a. paratuberculosis isolates in Norway may infect both cattle and goats.     

Surgical advancement of the larynx (laryngeal tie-forward) as a treatment for dorsal displacement of the soft palate in horses: a prospective study 2001-2004

REASONS FOR PERFORMING STUDY: Correct placement of sutures ('laryngeal tie-forward') in experimentally created dorsal displacement of the soft palate (DDSP) has been observed to replace the function of the thyrohyoideus muscles and prevent DDSP. HYPOTHESIS: The 'laryngeal tie-forward' procedure would prevent or delay the occurrence of DDSP during exercise in horses with naturally occurring DDSP and therefore improve performance. METHODS: A clinical population (n = 116), mainly of racehorses was presented for treatment of naturally occurring exercise-induced DDSP. All horses underwent the 'laryngeal tie-forward' procedure. The relative position of the thyroid and cricoid cartilage in relation to the caudal aspect of the basihyoid bone was recorded; follow-up was obtained by telephone communication with trainers, owners and/or referring veterinarians. In addition, a performance index and earnings were determined using race records. RESULTS: Preoperatively, the median distance between the caudal aspect of the basihyoid bone and rostral aspect of the thyroid cartilage was 3.5 cm. Post operatively, the thyroid cartilage was moved a median distance of 4 cm rostrally and the larynx was shown to be in a position more rostral and dorsal than in preoperative radiographs. Of 98 horses for which follow-up was available, the performance of 87% was classified as improved, 12% as unchanged and 2% as worse. In 20 horses in which the diagnosis had been confirmed by treadmill videoendoscopy, 80% had a significantly increased performance index and earnings (P = 0.007). For the entire population, there was a significant improvement in performance index and earnings after surgery (82%) (P = 0.0001). CONCLUSIONS: Placing the larynx in a more rostral and dorsal position may have improved the performance in 80-82% of the horses affected with naturally-occurring DDSP. POTENTIAL RELEVANCE: 'Laryngeal tie-forward' is a surgical technique that has a measurable effect on the position of the larynx and offers an alternative therapy for treating horses affected with DDSP. More experience may be needed with this technique prior to its widespread use in horses with a clinical diagnosis of DDSP.     

Use of avidity enzyme-linked immunosorbent assay and avidity Western blot to discriminate between acute and chronic Neospora caninum infection in cattle.

Avidity serological tests (avidity enzyme-linked immunosorbent assay [ELISA] and avidity Western blot) were developed and used to differentiate between acute (primary infection, reinfection, and recrudescence) and chronic Neospora caninum infection in cattle. In addition, the pattern of immunoglobulin G (IgG) avidity maturation against different specific antigens of N. caninum tachyzoites was studied. Sequential serum samples were collected from cattle naturally and experimentally infected with N. caninum. Four groups of experimentally infected cattle were included in the study and were representative of primary infection, reinfection, chronic infection, and noninfection. Serum samples were also collected from naturally infected cattle classified into nonaborting and aborting cows on the basis of clinical findings and serological profiles, and a third group composed of seronegative cows that seroconverted during the course of the experiment. All samples were tested by avidity ELISA and avidity Western blot. The IgG avidity ELISA allowed the discrimination between primary and chronic infection because all experimentally primary-infection cows showed low avidity indexes at week 4 postinfection (p.i.) compared with the high avidity values found at week 20 postinfection. However, this test did not allow the discrimination of reinfection or recrudescence from chronic infection. Regarding IgG avidity Western blot results, no antigenic markers correlating with acute (primary infection, recrudescence, and reinfection) or chronic infection were recognized. However, the 17-kD immunodominant antigen was mostly responsible for high avidity values obtained by avidity ELISA because it was intensively recognized by high-avidity antibodies in all chronically infected animals after urea treatment.     

Endocrine and cellular characteristics of corpora lutea from cows with a delayed post-ovulatory progesterone rise

The timing of the post-ovulatory progesterone rise is critical to the embryonic development and survival. The aim of this study was to determine the underlying causes of delayed post-ovulatory progesterone rises. Two groups of non-lactating dairy cows with early (n = 11) or late (n = 9) post-ovulatory progesterone rises were created by inducing luteolysis in the presence of either a large (> 10 mm) or small (< 10 mm) follicle, respectively. LH pulses were measured on days 4 (all cows) and 7 (n = 7, early; n = 5, late) (day 1= ovulation). The cows were slaughtered on day 5 (n = 4 each group) or 8 (n = 7, early; n = 5, late). Immunohistochemical analysis for endothelial cells (von Willebrand Factor, VWF), steroidogenic cells (3beta-HSD) and proliferation marker (Ki67) were performed. The basal progesterone production and LH responsiveness (0.001-100 ng/ml) of dispersed luteal cells was investigated. The luteal concentrations of FGF-2 and VEGF were measured by ELISA and RIA, respectively. There were no differences in LH pulse characteristics, area of VWF staining, proliferation index, steroidogenic cell characteristics, basal or LH-stimulated progesterone production by luteal cells between cows with an early or late progesterone rise (P > 0.10). However, the area of VWF staining increased from days 5 to 8, while the proliferation index decreased (P < 0.05). Furthermore, the luteal cells were more responsive to LH on day 8 (P < 0.01). Luteal concentrations of FGF-2 were higher on day 5 (P = 0.05), while VEGF was greater on day 8 (P < 0.01). In conclusion, we have clearly shown that LH support, degree of vascularization or luteal cell steroidogenic capacity were not the major factors responsible for inadequate secretion of progesterone by the developing bovine CL.