Effects of physiologic agonists on canine whole blood flow cytometry assays of leukocyte-platelet aggregation and platelet activation

Platelets play a role in both the innate and adaptive immune systems. Methods for detecting activated platelets and leukocyte-platelet aggregates (LPAs) are useful for basic and applied research concerning the role of platelets in inflammation and immune disorders. The aim of the study was to develop flow cytometric assays for detection of platelets binding to monocytes and neutrophils and for activated platelets in canine whole blood and to investigate the effect of physiologic agonists. Citrate anticoagulated whole blood was incubated with monoclonal antibodies against CD14 and CD61 for detection of LPAs, and the effect of various agonists was investigated. For detection of activated platelets, whole blood was incubated with monoclonal antibodies against CD62P and against a receptor-induced binding site on fibrinogen (CAP1) with CD61 as a platelet identifier. Isotype controls were prepared in parallel. The individual physiologic agonists ADP, collagen and epinephrine increased LPAs, CD62P and CAP1 binding only modestly. However, combinations of agonists gave more substantial increases. A dose-response relationship was seen using alpha- and gamma-thrombin, and ADP as agonists. In conclusion, we have developed flow cytometry assays to measure LPAs and platelet activation in canine whole blood, and have explored the effect of various physiologic agonists at different concentrations.     

Novel papillomavirus isolated from the oral mucosa of a polar bear does not cluster with other papillomaviruses of carnivores

Papillomatosis has been documented in several carnivores, and papillomavirus (PV) types have been characterized from lesions in a number of carnivore species: the canine oral PV (COPV), the Felis domesticus PV type 1 (FdPV-1) isolated from a Persian cat, the Procyon lotor PV type 1 (PlPV-1) isolated from a raccoon, the canine PV type 2 (CPV-2) from a dog's foot pad lesion and the canine PV type 3 (CPV-3) associated with a canine epidermodysplasia verruciformis - like disease. A tissue sample was taken from a papillomatous lesion on the oral mucosa of a polar bear (Ursus maritimus). Extracted DNA was used as a template for multiply primed rolling-circle amplification (RCA), and restriction enzyme analysis of the RCA product indicated the presence of papillomaviral DNA. The genome of this PV was cloned and the complete genomic sequence was determined. The Ursus maritimus PV type 1 (UmPV-1) genome counts 7582 basepairs and is smaller than that of other papillomaviruses from carnivore species. UmPV-1 contains the typical noncoding region NCR1, but unlike the carnivore PVs of the Lambda genus, UmPV-1 does not possess a second noncoding region NCR2. Phylogenetic analysis based on a nucleotide sequence alignment of the L1 ORF of UmPV-1 and 51 other PV types indicates that UmPV-1 does not cluster with any of the other carnivore PVs, but branches off near the root of the common branch of the genus Alphapapillomavirus.     

The effect of Holistic Planned Grazing™ on African rangelands: a case study from Zimbabwe

Holistic Planned Grazing? (HPG) is purported to have positive long-term effects on rangelands, enhancing ecosystem services. Given comparable environmental templates, but different management regimes, vegetation monitoring and landscape function analysis showed the Africa Center for Holistic Management (ACHM) at Dimbangombe had a significantly higher rangeland condition (composition, cover, standing crop and soil health) than adjacent Sizinda (SCR) and Monde (MCR) communal rangelands. Overall grazer density on ACHM is 42% higher than that of SCR (no data for MCR). Finer-scale satellite collar data for ACHM yielded a calculated stocking rate of 0,55 LSU ha^-1 y^-1 or 24 590 kg km^-2, which constitutes high-density grazing. An energy flow estimate shows that the grazing resource would, on average, not be limiting for livestock on ACHM but limiting on SCR. HPG may include an element where kraals are inserted into degraded rangelands for a short period. Overall, ACHM shows stable perennial composition with smaller tufts significantly closer together. A similar result was visible in SCR where maize yields were visibly higher on kraaled areas than on adjacent untreated fields. HPG yields positive long-term effects on ecosystem services (soils and vegetation) and points to the HPG approach enhancing the sustainability of livestock and wildlife in this environment.     

Ultrasonographic anatomy of the atlanto‐occipital region and ultrasound‐guided cerebrospinal fluid collection in rabbits (Oryctolagus cuniculus)

Cerebrospinal fluid analyses are important for diagnosis of neurologic problems in rabbits and for translational research projects using rabbits as models. Blind puncture of the cisterna magna is the current standard technique for sampling cerebrospinal fluid in this species. However, the complexity and small size of the cisterna magna and surrounding structures are limitations of this technique. Aims of this prospective, anatomic, pilot study were to (1) describe the normal anatomy of the atlanto‐occipital region, (2) describe ultrasonographic anatomic landmarks, and (3) develop and evaluate a technique for ultrasound‐guided puncture of the cisterna magna for cerebrospinal fluid sampling in rabbits. Thirty healthy rabbits were included and the study was conducted in three stages. Three rabbit cadavers were used for the first stage of the study. Then, the second stage was completed using 13 rabbit cadavers. Finally, the third stage was completed in 14 live rabbits. The ultrasound‐guided puncture performed in 13 cadavers was successful at the first attempt in 10 cases, and at the second attempt in the remaining three cases. In the in vivo study, the ultrasound‐guided puncture was successful in all 14 cases, without signs of complications. Findings supported the use of ultrasound‐guided puncture of the cisterna magna as a safe technique that may be used routinely or when the sample of cerebrospinal fluid cannot be obtained with the blind technique in rabbits.     

Integrated freshwater aquaculture,crop and livestock production in the Mekong delta,Vietnam: Determinants and the role of the pond

Promotion of integrated aquaculture with agriculture, including crops and livestock (IAA-farming), requires consideration of both bio-physical and socio-economic contexts. The major factors influencing the adoption of IAA-farming by households at three sites in the Mekong delta were identified. Special attention was given to the multiple roles ponds play in IAA-farming systems. Information was collected through semi-structured interviews and discussions with focus groups and key individuals. Data were analyzed using multivariate factor analysis, analysis of variance or participatory ranking methods. Three major IAA-systems were identified: (1) low-input fish farming integrated with intensive fruit production (system 1), (2) medium-input fish farming integrated with less intensive fruit production (system 2), and (3) high-input fish farming integrated with less intensive fruit production (system 3). System 1 was commonly practised in a rural fruit-dominated area with fertile soils, while systems 2 and 3 were more evident in peri-urban rice-dominated areas with less fertile soils. In the study area, only 6% of poor farmers adopted IAA-farming, while this was 42% for intermediate and 60% for rich households. Richer farmers tended to intensify fish farming and seek a more commercial orientation. The major factors why farmers did not start aquaculture were the inappropriateness of technology, insufficient land holding or poor access to extension services, limited farm management, and through a fear of conflicts associated with pesticide use on crops. The main motivations for practising IAA-farming included increased income and food for home consumption from the available farm resources while reducing environmental impacts. Further improvements to IAA-systems can be realized by strengthening nutrient recycling between different IAA-system components while enhancing farming output and safeguarding the environment.     

Relationship of tibial plateau slope to limb function in dogs treated with a lateral suture technique for stabilization of cranial cruciate ligament deficient stifles

OBJECTIVE: To evaluate the effect of a lateral suture technique (LST) on tibial plateau angle (TPA) measurement and to compare TPA with functional outcome in dogs treated for cranial cruciate ligament (CrCL) rupture with LST. STUDY DESIGN: Prospective clinical study. SAMPLE POPULATION: Dogs (n=34) with unilateral CrCL instability. METHODS: All dogs had lameness examination, survey stifle radiographs, and force plate analysis before and at 6, 12, 24, and 48 weeks after surgery. Radiographic osteoarthritis (OA) scores and lameness scores were assigned using previously reported methods. Preoperative radiographs were performed in all dogs, and postoperative serial radiographs were performed in 6 dogs for measurement of TPA. Differences in TPA measurements were evaluated with a random effects repeated measures model. The significance of LST on TPA measurement was established in 6 dogs and the effect of TPA on vertical impulse, peak vertical force, progression of radiographic scores, and lameness score were analyzed by general linear models in all dogs. Differences were considered significant if P<.05. RESULTS: Significant differences were not noted between pre- and serial postoperative measurements of TPA. A significant correlation was not established between TPA and postoperative vertical impulse, peak vertical force, lameness score, or radiographic OA scores. CONCLUSIONS: TPA values were unchanged after LST and TPA does not affect outcome measures in dogs treated with LST. CLINICAL RELEVANCE: TPA has no predictive value on clinical outcome in dogs treated with LST for stabilization of CrCL deficient stifles.     

Passive immunization to reduce Campylobacter jejuni colonization and transmission in broiler chickens

Campylobacter jejuni is the most common cause of bacterium-mediated diarrheal disease in humans worldwide. Poultry products are considered the most important source of C. jejuni infections in humans but to date no effective strategy exists to eradicate this zoonotic pathogen from poultry production. Here, the potential use of passive immunization to reduce Campylobacter colonization in broiler chicks was examined. For this purpose, laying hens were immunized with either a whole-cell lysate or the hydrophobic protein fraction of C. jejuni and their eggs were collected. In vitro tests validated the induction of specific ImmunoglobulinY (IgY) against C. jejuni in the immunized hens’ egg yolks, in particular. In seeder experiments, preventive administration of hyperimmune egg yolk significantly (P < 0.01) reduced bacterial counts of seeder animals three days after oral inoculation with approximately 10⁴ cfu C. jejuni, compared with control birds. Moreover, transmission to non-seeder birds was dramatically reduced (hydrophobic protein fraction) or even completely prevented (whole-cell lysate). Purified IgY promoted bacterial binding to chicken intestinal mucus, suggesting enhanced mucosal clearance in vivo. Western blot analysis in combination with mass spectrometry after two-dimensional gel-electrophoresis revealed immunodominant antigens of C. jejuni that are involved in a variety of cell functions, including chemotaxis and adhesion. Some of these (AtpA, EF-Tu, GroEL and CtpA) are highly conserved proteins and could be promising targets for the development of subunit vaccines.     

COMPUTED TOMOGRAPHIC CHARACTERISTICS OF COLLATERAL VENOUS PATHWAYS IN DOGS WITH CAUDAL VENA CAVA OBSTRUCTION

Collateral venous pathways develop in dogs with obstruction or increased blood flow resistance at any level of the caudal vena cava in order to maintain venous drainage to the right atrium. The purpose of this retrospective study was to describe the sites, causes of obstruction, and configurations of venous collateral pathways for a group of dogs with caudal vena cava obstruction. Computed tomography databases from two veterinary hospitals were searched for dogs with a diagnosis of caudal vena cava obstruction and multidetector row computed tomographic angiographic (CTA) scans that included the entire caudal vena cava. Images for each included dog were retrieved and collateral venous pathways were characterized using image postprocessing and a classification system previously reported for humans. A total of nine dogs met inclusion criteria and four major collateral venous pathways were identified: deep (n = 2), portal (n = 2), intermediate (n = 7), and superficial (n = 5). More than one collateral venous pathway was present in 5 dogs. An alternative pathway consisting of renal subcapsular collateral veins, arising mainly from the caudal pole of both kidneys, was found in three dogs. In conclusion, findings indicated that collateral venous pathway patterns similar to those described in humans are also present in dogs with caudal vena cava obstruction. These collateral pathways need to be distinguished from other vascular anomalies in dogs. Postprocessing of multidetector‐row CTA images allowed delineation of the course of these complicated venous pathways and may be a helpful adjunct for treatment planning in future cases.     

Influence of tropical seasonal changes on oocyte diameter, responses to hormonal induction and hatching quality in two strains of the catfish, Heterobranchus longifilis Val. (Clariidae)

A comparison was made between the oocyte diameter, pseudo‐absolute fecundity (PAF) and egg quality of two strains of the catfish, Heterobranchus longifilis, maintained in outdoor ponds under a tropical highland climate in Cameroon. The results indicated that circannual endogenous rhythms for ovarian recrudescence and regression are absent in H. longifilis, irrespective of breeding history, age and strain. There appeared to be a possible slight adverse effect of climate (dry season) on reproductive performance of both strains. Oocyte diameter and PAF increased with increasing fish weight when data from both strains were combined, indicating that the two strains may exhibit the same reproductive performance. Viable eggs were obtained all year round after hormonal induction. It is concluded that for propagation of H. longifilis in tropical African countries, broodfish could be maintained in outdoor earthen fish ponds with proper feeding.     

Exploring the trophic structure in organically fertilized and feed-driven tilapia culture environments using multivariate analyses

Reports of similar yields in manure and feed‐driven tilapia culture environments raise questions on food utilization in these environments. The possibility that similar production rates are because of utilization of different foods was investigated using exploratory techniques of multivariate analyses. Using factor analysis, trophic pathways through which food becomes available to fish were explored, and using anova models, water quality, sediment quality and tilapia growth and yields were compared. Conceptual graphic models of the main ecological processes occurring in feed‐driven and organically fertilized environments are presented and discussed. In both environments, autotrophic and heterotrophic pathways are important processes that result in the availability of natural foods that are utilized by the fish. Extrapolated fish yield data indicate that with equal nutrient input and stocking density, organically fertilized environments could achieve production rates similar to those in feed‐driven environments. The general assumption that supplemental or complete foods are well utilized by tilapia in outdoor stagnant ponds remains challenged, and further research on tilapia feeding behaviour and food selection in feed‐and organic fertilizer‐driven environments is needed.