Jejunal mucosal lactase activity from birth to three weeks in conventionally raised calves fed an electrolyte solution on days 5, 6 and 7 instead of milk.

The purpose of this study was to evaluate the effect of withdrawal of lactose from the diet for 72 hours on lactase activity in the jejunal mucosa of conventionally raised calves. The descending portion of the duodenum of six Holstein calves less than 24 hours old was cannulated. The calves were fed milk except on days 5, 6 and 7 when they were given the same volume of an electrolyte solution. Sequential biopsy specimens of the proximal jejunal mucosa were obtained for three weeks and the lactase activity determined. Lactase activity was highest on day 1 and a trend toward decreased lactase activity from birth until three weeks was observed. Mean lactase activity was significantly (p less than 0.05) higher for days 1, and 3 compared to days 9, 13 and 17. The withdrawal of milk and replacement by an electrolyte solution during three days had no significant effect on jejunal mucosal lactase activity in neonatal calves.     

Estrogen suppresses melatonin-enhanced hyperactivation of hamster spermatozoa

Hamster sperm hyperactivation is enhanced by progesterone, and this progesterone-enhanced hyperactivation is suppressed by 17β-estradiol (17βE₂) and γ-aminobutyric acid (GABA). Although it has been indicated that melatonin also enhances hyperactivation, it is unknown whether melatonin-enhanced hyperactivation is also suppressed by 17βE₂ and GABA. In the present study, melatonin-enhanced hyperactivation was significantly suppressed by 17βE₂ but not by GABA. Moreover, suppression of melatonin-enhanced hyperactivation by 17βE₂ occurred through non-genomic regulation via the estrogen receptor (ER). These results suggest that enhancement of hyperactivation is regulated by melatonin and 17βE₂ through non-genomic regulation.     

Echinococcus multilocularis in Belgium: prevalence in red foxes (Vulpes vulpes) and in different species of potential intermediate hosts

Echinococcus multilocularis causes a rare but potentially lethal zoonotic infection in humans. This tapeworm is known to be endemic in foxes in several countries of Western and Central Europe. In Western Europe, the common vole (Microtus arvalis) and the water vole (Arvicola terrestris) are considered to be the most important intermediate host species of this cestode whereas the red fox is by far the most important final host. The purpose of this study was to provide data on the prevalences in Wallonia (Southern part of Belgium) both in the red fox and in different potential intermediate hosts. A total of 990 red foxes were examined between January 2003 and December 2004 for the presence of E. multilocularis. The average prevalence was 24.55% (22.38-27.87). Out of 1249 rodents or insectivores belonging to the species Apodemus sylvaticus, Arvicola terrestris, Clethrionomys glareolus, Microtus arvalis, Microtus agrestris and Sorex araneus, only one M. arvalis (out of 914-0.11% (0.003-0.61) and one C. glareolus (out of 23-4.3% (0.1-21.9) were found to be infected. However, the muskrat (Ondatra zibethicus) seems to be a good intermediate host as 11.18% (9.72-12.76) of the animals (n=1718) were found to be infected. A positive correlation was found between the prevalences in foxes and in muskrats in each of the different geological regions. This study indicates that the muskrat is highly sensitive to this zoonotic tapeworm and could perhaps represent a good bioindicator when studying the epidemiology of this parasitic infection in Belgium and in other countries where the muskrat is present.     

Use of radiographic measures and three-dimensional computed tomographic imaging in surgical correction of an antebrachial deformity in a dog

CASE DESCRIPTION: A 1-year-old 7.4-kg (16.3-lb) castrated male mixed-breed dog was evaluated because of intermittent lameness and an antebrachial angular limb deformity. CLINICAL FINDINGS: The left forelimb had gross antebrachial external rotation (approx 90 degrees ) and marked procurvatum. Radiography revealed a severe partially compensated biapical antebrachial angular limb deformity. Measurements of medial proximal radial angle (MPRA) and lateral distal radial angle (LDRA) were obtained from orthogonal radiographs of the proximal and distal segments of the radius, respectively. Elbow joint-to-carpus translation was quantified. Deformities were localized and quantified by the center of rotation of angulation (CORA) method. Computed tomographic 3-dimensional image reconstructions of the antebrachium and carpus were completed to create 3 life-size stereolithographic models. TREATMENT AND OUTCOME: 2 closing wedge radial osteotomies were performed at the level of the CORAs and stabilized with bone plates and screws. RESULTS: Frontal and sagittal plane alignments were corrected to 8 degrees and 15 degrees , respectively (reference limits, 0 degrees to 8 degrees and 8 degrees to 35 degrees , respectively). The MPRA was corrected from 55 degrees to 68 degrees , and LDRA was corrected from 32 degrees to 76 degrees (values considered normal are approx 85 degrees and 87 degrees , respectively). Elbow joint-to-carpus translation was improved by 42.5%. After 8 weeks, radiography revealed bone union. Owners considered the outcome acceptable, on the basis of limb appearance and lack of lameness at 1 year after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: A segmental radiographic planning technique combined with the CORA method, computed tomography, and stereolithography may be useful in the characterization of and planning corrective surgery for forelimb deformities in dogs.     

Pseudorabies virus infection in mink: a host-specific pathogenesis

Pseudorabies virus (PRV) is an alphaherpesvirus that causes a neurological disease in many wild and domestic animals. The neuropathology elicited by PRV is quite consistent regardless of the host with the only exception of mink, in which it is characterized by a vasculopathy rather than by an encephalitis. In this study, we aimed to investigate the underlying pathogenic mechanism(s) of PRV infection in mink by using immunohistochemistry and laser capture microdissection (LCM) on material from naturally and experimentally infected animals. The inflammatory reaction induced by PRV was minimal or absent not only in the nervous system, where we identified a low number of macrophages and a few T lymphocytes, but also in the primary replication site, the oropharyngeal mucosa; however, the number of PRV-infected cells detected by immunohistochemistry was extremely high both in the peripheral mucosa and in the nervous tissue. On the other hand, the vascular pathology included parenchymal hemorrhages of various degrees and, in specific cortical areas of the brain, fibrinoid degeneration of the capillary walls. Detection of viral antigens by immunohistochemistry revealed infection of endothelial cells of capillaries situated both in the oropharyngeal mucosa and in the brain stem; the presence of PRV DNA in vessels was further demonstrated by PCR performed on LCM samples of brain capillaries. These results can be interpreted as supporting the idea that the different pathology of the disease in mink may be the consequence of an increased endotheliotropism of PRV in this species. Infection of the vessel wall may then lead to vascular pathology and impairment in endothelial cell function, resulting in a weak immune response to infection.     

Clinical differentiation between dogs with benign and malignant spirocercosis

Spirocerca lupi is a nematode infesting the canine oesophagus, where it induces the formation of a nodule that may transform into a malignant sarcoma. The current, retrospective study compared the clinical presentation, haematology, serum albumin and globulin and radiology of benign cases (n=31) and malignant cases (n=31) of spirocercosis. Dogs with spirocercosis-induced sarcoma were significantly older (6.4+/-1.91 years) than benign cases (4.93+/-2.87). In the malignant cases there were significantly (p=0.03) more sterilized females (10/31) and fewer intact males (4/31) compared to 2/31 and 13/31, respectively, in the benign cases. Hypertrophic osteopathy was observed in 38.7% of malignant cases and in none of the benign cases (p=0.0002). Common clinical signs included weight loss, regurgitation, anorexia, pyrexia (T>or=39.5 degrees ), respiratory complications and salivation but did not differ in prevalence between groups. On haematology, the malignant group had significantly (p<0.05) lower haematocrit (0.34+/-0.08 vs. 0.41+/-0.07) and higher white cell count (31.6+/-27.83 vs. 17.71+/-13.18 x 10(3)microl(-1)), mature neutrophil count (26.06+/-26.08 vs. 12.23+/-9.96 x 10(3)microl(-1)) and thrombocyte count (493.15+/-151.61 vs. 313.27+/-128.54 x 10(9)microl(-1)). There were no differences in the mean corpuscular volume and immature neutrophil count. On radiology, the mass length was not significantly different, but the height and the width of the malignant masses were significantly larger (62.59+/-15.15 mm and 73.93+/-20.94 mm) compared to the benign group (46.43+/-23.62 and 49.29+/-25.56, respectively). Spondylitis was more prevalent in the malignant group (67.86% vs. 38.46%, p=0.03). Examining secondary pulmonary changes revealed significantly higher prevalence of bronchial displacement in the malignant group (52% vs. 17%, p=0.008). Hypertrophic osteopathy appeared to be a very specific but relatively rare (poor sensitivity) marker of malignancy. Female gender, anaemia, leukocytosis, thrombocytosis, spondylitis and bronchial displacement are significantly more common in malignant cases, but appear in benign cases as well. However, if found together in a specific case, they should increase the index of suspicion for malignancy in a diagnosed spirocercosis case.     

Evaluation of Salmonella-lytic properties of bacteriophages isolated from commercial broiler houses

Because of recent interest in bacteriophage therapy in poultry, information regarding the interaction of bacteriophages and potential host bacteria in the environment should be collected. The present studies were initiated with a rather typical commercial broiler integrator within the south-central United States to examine environmental Salmonella levels in two broiler complexes, attempt to isolate Salmonella-lytic bacteriophages, and elucidate a possible reason for differing apparent Salmonella prevalence. Significantly (P < 0.05) less Salmonella was isolated from houses in complex 1 (15/44 [34%] Salmonella-positive drag swabs) as compared to houses in complex 2 (22/24 [92%]). A total of seven Salmonella-lytic bacteriophages were isolated from Salmonella-positive environments, and two bacteriophages were isolated from a single Salmonella-negative house. During the initial bacteriophage isolation, individual bacteriophages did not replicate in the Salmonella host isolated from the same environment, and lysis of additional Salmonella hosts relied on high numbers of bacteriophage to be present. This suggests that the presence of these bacteriophages in the environment of a commercial broiler house had little to no effect on the presence of Salmonella. This study highlights the need to find additional bacteriophage sources, more effective isolation methods, and more innovative approaches to using bacteriophages to treat enteric disease.     

Bovine NK cells acquire cytotoxic activity and produce IFN-gamma after stimulation by Mycobacterium bovis BCG- or Babesia bovis-exposed splenic dendritic cells

Early interactions of innate immune cell populations, such as dendritic cells (DC) and natural killer (NK) cells, can affect the ability of the acquired immune response to control infection of intracellular microorganisms. In this study, we investigated the activation of bovine NK cells by CD13(+) splenic DC stimulated with either Mycobacterium bovis BCG or Babesia bovis merozoites. Splenic DC were used either immediately after selection (cytokine(-)) or after exposure to GM-CSF, IL-4 and Flt3L for 72 h (cytokine(+)). Phenotypic analyses showed up-regulation of MHCII, CD80 and CD86 on cytokine(+) DC when compared to cytokine(-) DC. Purified NK cells (CD335(+)CD3(-)CD2(+/-)CD8alpha(+/-)) were co-cultured with microbial-exposed cytokine(-) DC or cytokine(+) DC in either transwell or cell-to-cell format and NK cell IFN-gamma production and cytotoxicity were assessed. NK cell IFN-gamma production was dependent on cell-to-cell contact. Microbial-stimulated cytokine(+) DC induced significantly more IFN-gamma production from NK cells than cytokine(-) cells. In contrast, cytotoxicity and perforin up-regulation were more pronounced in NK cells cultured with cytokine(-) DC than cytokine(+) DC. Therefore, activation of bovine NK cells by microbial-stimulated CD13(+) splenic DC is influenced by the maturation state of the DC suggesting different roles for the splenic DC during disease-induced maturation.     

Optimization and validation of a flow cytometric method for immunophenotyping peripheral blood lymphocytes from cynomolgus monkeys (Macaca fascicularis)

BACKGROUND: Guidelines published by the Food and Drug Administration and Center for Human Medicinal Products describe the need to assess immunotoxic effects in nonclinical studies that evaluate drug toxicity, including the use of immunophenotyping to measure immunotoxicity. We are not aware of previous studies, however, that have validated methods for immunophenotyping peripheral blood lymphocyte subsets in whole blood samples from cynomolgus monkeys. OBJECTIVE: The purpose of this study was to optimize and validate a flow cytometric assay for immunophenotyping lymphocytes in the peripheral blood of cynomolgus monkeys. METHODS: A series of prevalidation experiments were done to determine optimal reagents, volumes, timing, and other procedural details of the flow cytometric assay. Using the optimized method, we then determined precision, interindividual variation, laboratory-to-laboratory variability, and sample stability. Stabilized human blood was used as a positive control for staining, processing, and analysis. The percentage and number of pan-T cells (CD3+), T-helper cells (CD3+4+), T cytotoxic/suppressor cells (CD3+8+), natural killer cells (CD3-16+), and B-cells (CD3-20+) were determined in 146 male and 140 female, clinically healthy monkeys and reference intervals were calculated. RESULTS: By doing 4-color staining with a lyse-wash method, intra- and interassay precision were <5% for all lymphocyte subsets. Variability between technicians and laboratories was minimal (CVs<3%). Samples were stable for up to 24 hours after staining and fixing. CONCLUSIONS: The validated method is extremely robust and can be performed under good laboratory practice conditions to support nonclinical studies. Reference intervals for lymphocyte subsets were similar to those previously reported.     

Virulence factors and antimicrobial susceptibility of Escherichia coli isolated from calves in Turkey

Escherichia coli isolates from calves were investigated by multiplex PCR assays for the presence of genes encoding K99, F41, F17-related fimbriae, heat-stabile enterotoxin a (STa), intimin (eae) and Shiga toxins (stx1 and stx2). A total of 120 E. coli isolates, 75 isolated from diarrhoeic or septicemic calves and 45 from clinically healthy calves aged between 1 day and 2 months were tested. Each isolate was obtained from different calves in different herds. Among the isolates from diseased animals, 12 (16%) isolates from 1- to 7-day-old diarrhoeic calves were detected as enterotoxigenic E. coli which possessed K99, F41 and STa in combination; F17-related fimbriae genes were detected in 33 (44%) isolates and they were found in combination with K99 + F41 + STa in two isolates. Of 120 isolates, 16 carried eae, eight stx1 and five stx2 genes alone or in combination. None of the eae- or stx-positive strains was identified as O157:H7. However, results indicate that calves may be carrier of Shiga toxin-producing E. coli which have potential as a human pathogen. Antimicrobial susceptibility of 75 isolates from diseased calves was determined by agar disk diffusion method for 14 antimicrobial agents. In 77.3% of the isolates, multiresistance was detected. Higher resistance rates were detected for cephalothin (72%), tetracycline (69.3%), kanamycin (69.3%), ampicillin (65.3%), nalidixic acid (53.3%), trimethoprim-sulphamethoxazole (52%) and enrofloxacin (41.3%), respectively. No resistance was found for ceftiofur and cefoxitin.