BCG vaccination of neonatal calves: potential roles for innate immune cells in the induction of protective immunity

Bovine tuberculosis is a disease of increasing incidence in the UK causing major economic losses and with significant impact on bovine and, potentially human health: the causative agent Mycobacterium bovis is a zoonotic pathogen. Neonatal vaccination with the attenuated M. bovis Bacille Calmette Guerin (BCG) vaccine confers a significant degree of protection in cattle, and is a widely used control strategy for human TB. The adaptive immune system is relatively immature in neonates and increased numbers of innate effector cells present in young animals and human infants may compensate for this, enabling effective immune responses to vaccination. Natural killer cells and subsets of γδ TCR+ T lymphocytes secrete high levels of interferon gamma and can interact with antigen presenting cells to promote both innate and adaptive immune responses. These cell populations may be pivotal in determining immune bias following neonatal vaccination with BCG.     

Antithrombotic Therapy

Thrombosis or thromboembolism are significant concerns in companion animals and can be associated with cardiac, metabolic, neoplastic disease processes or can be one manifestation of inflammatory, infectious, and neoplastic disease conditions. Options for thromboprophylaxis available for clinical use in small animal patients are very limited, with heparin (primarily unfractionated, but more recently low-molecular-weight forms) and aspirin predominating. Controlled studies evaluating the use of these drugs are few, but there is some limited evidence for efficacy in prevention of formation of thrombi. Use of the vitamin K antagonist warfarin has been described, but the narrow therapeutic window has resulted in a high rate of serious adverse events. In human patients, the efficacy of aspirin, heparins, and vitamin K antagonists is well documented in a variety of thrombotic conditions, but there are significant limitations to each of these options. These limitations have prompted the search for new alternatives, some of which are now in wide clinical use in humans. Although the use of some of the drugs discussed here has not yet been described in veterinary patients at risk for thrombosis, many of these agents have been evaluated experimentally in dogs, cats, or both. These new thromboprophylactic agents may soon be beneficial in management of small animal patients at risk for thrombosis.     

Canine corneal fibroblast and myofibroblast transduction with AAV5

Objective The aims of this study were (1) to determine the efficacy of adeno‐associated vector serotype 5 (AAV5) for delivering gene therapy to canine corneal fibroblasts (CCFs) and myofibroblasts (CCMs) using enhanced green fluorescent protein (GFP) marker gene and (2) to evaluate the cytotoxicity of AAV5 to CCFs and CCMs using an in vitro model. Methods Healthy donor canine corneas were used to generate primary CCFs by growing cultures in minimal essential medium supplemented with 10% fetal bovine serum. Canine corneal myofibroblasts were produced by growing cultures in serum‐free medium containing transforming growth factor β1 (1 ng/mL). An AAV5 titer (6.5 × 10¹² μg/mL) expressing GFP under control of hybrid cytomegalovirus + chicken β‐actin promoters (AAV5‐gfp) was used to transduce CCF and CCM cultures. Delivered gene expression in CCFs and CCMs was quantified using immunocytochemistry, fluorescent microscopy, and real‐time PCR. Transduction efficacy of the AAV5 vector was determined by counting DAPI‐stained nuclei and EGFP‐positive cells in culture. Phase‐contrast microscopy, trypan blue, and dUTP nick end labeling (TUNEL) assays were used to determine the toxicity and safety of AAV5 in this canine corneal model. Results Topical AAV5 application successfully transduced a significant population of CCFs (42.8%; P < 0.01) and CCMs (28%; P < 0.01). Tested AAV5 did not affect CCF or CCM phenotype or cellular viability and did not cause significant cell death. Conclusions The tested AAV5 is an effective and safe vector for canine corneal gene therapy in this in vitro model. In vivo studies are warranted.     

Circulatory, respiratory and behavioral responses in isoflurane anesthetized llamas

Objectives To evaluate the circulatory, respiratory and behavioral effects of isoflurane (ISO) anesthesia in llamas during mechanical ventilation and spontaneous breathing. Design Prospective randomised study. Animals Six adult, neutered male llamas (10 ± 1 years [mean ± SD], 179 ± 32 kg). Materials and methods Animals in which the minimum alveolar concentration (MAC) had been previously determined were anesthetized with ISO in oxygen. Inspired and end‐tidal (ET) ISO were sampled continuously. Arterial blood pH, respiratory and circulatory variables, and clinical signs of anesthesia were recorded at three doses (1.0, 1.5 and 2.0 times the individual animal's MAC; mean MAC value 1.13%) of ISO during spontaneous and controlled ventilation. A series of Latin squares was used to determine order of dose. Controlled ventilation (CV) (target PaCO₂ 38 ± 5 mm Hg [5.0 ± 0.6 kPa]) preceded spontaneous ventilation (SV) at each dose. Animals breathed spontaneously for approximately 10 minutes prior to data collection. Body temperature was maintained at 37 ± 0.6 °C. Circulatory and respiratory data were analysed with a mixed model, least squares analysis of variance, for repeated measures taken at equally spaced intervals. p < 0.05. Results Dose and mode of ventilation had significant influences on measured variables. For example, heart rate increased as dose increased; 67 ± 14 beats minute^?1 at 1.0 MAC‐CV versus 77 ± 6 beats minute^?1 at 2 MAC‐CV. Conversely, mean arterial pressure decreased with increasing dose; 82 ± 13 mm Hg at MAC‐CV versus 52 ± 15 mm Hg at 2 MAC‐CV. Arterial CO₂ increased with increasing dose during SV; 45 ± 5 mm Hg [6 ± 0.6 kPa] at MAC versus 53 ± 4 mmHg [7 ± 0.5 kPa] at 2 MAC. Reflex activity (e.g. palpebral reflex) and muscle tone (e.g. jaw tone) decreased while eyelid aperture increased with increasing anesthetic dose. Conclusions and Clinical Relevance The influence of ISO dose and mode of ventilation on circulatory and respiratory variables in llamas is qualitatively similar to that reported in other species. Changes in reflex activity and muscle tone may be used to guide appropriate anesthetic delivery in ISO‐induced llamas.     

Immunoblotting, ELISA and culture evidence for Chlamydiaceae in sows on 258 Belgian farms

The prevalence of Chlamydiaceae infections on 258 closed pig breeding farms in Belgium was examined. For this purpose, 258 farms were randomly selected in the provinces West-Vlaanderen (44%), Oost-Vlaanderen (20%), Antwerpen (10%) and Vlaams-Brabant (6%). Of all farms examined, 96.5% were positive for Chlamydia-specific antibodies in ELISA and most were moderately to strongly positive. ELISA results revealed only 9 (3.5%) sero-negative farms. None of the ELISA negative sera reacted in immunoblotting. Only 212 of 249 ELISA positive sera reacted positive in immunoblotting. Additionally, 23 autopsy samples were examined by isolation in Vero cells. The major outer membrane sequence of the one isolate obtained showed 98.6% amino acid homology to the one of Chlamydophila psittaci strain CP3, formerly isolated from a pigeon. Present observations indicate that chlamydial infections are nearly endemic in the Belgian pig population and that Belgian pigs can become infected with C. psittaci. Nevertheless, the role and significance of Chlamydiaceae as pathogens in pigs remain unsolved and require further investigation.     

MAGNETIC RESONANCE IMAGING OF THE CANINE ABDOMEN: EFFECT OF PULSE SEQUENCE ON DIAGNOSTIC QUALITY

Motion artifact is an important limiting factor for abdominal magnetic resonance imaging (MRI) in veterinary patients. The purpose of this study was to determine the effects of pulse sequence on abdominal MRI diagnostic quality in dogs. Ten normal dogs were each scanned using 16 MRI pulse sequences. Sequences included breath‐holding sequences, respiratory navigation sequences, and traditional spin‐echo sequences. Four observers independently scored diagnostic quality for each sequence based on the appearance of specific organs, overall diagnostic quality, and degree of artifactual interference. Signal‐to‐noise ratio and contrast‐to‐noise ratio were also calculated for each sequence. The sequence with the highest overall mean diagnostic quality score was the dorsal T2 turbo spin echo (TSE) with fat saturation and breath‐holding. The sequence with the lowest mean diagnostic quality score was the dorsal T2 fast spin echo. The sequence with the highest signal‐to‐noise ratio for all evaluated organs was the sagittal T1 spin echo. Signal‐to‐noise and contrast‐to‐noise ratios did not correlate with subjective assessment of overall diagnostic quality for the majority of the sequences evaluated (P < 0.05). The three sequences considered to have the highest diagnostic quality for the cranial abdomen were the dorsal T2 TSE with fat saturation and breath‐hold, transverse T1 turbo fast low‐angle shot gradient echo with breath‐hold, and dorsal T2 half‐Fourier acquisition single shot TSE with respiratory navigation. These sequences had short acquisition times, yielded studies of similar diagnostic quality, provided complementary information, and are therefore recommended for routine canine abdominal MRI protocols.     

The Impact of Hardwood Line-Planting on Tree and Amphibian Diversity in a Secondary Subtropical Wet Forest of Southeast Puerto Rico

The impact on tree and amphibian diversity of line-planting of tropical hardwoods—mahogany (Swietenia macrophylla × S. mahagoni) and mahoe (Hibiscus elatus)—was studied in a secondary subtropical wet forest of Puerto Rico. Common coqui (Eleutherodactylus coqui) and melodious coqui (E. wightmanae) are the most frequent frog species; forest coqui (E. portoricensis) is less abundant. Although relative abundance means were slightly greater in the undisturbed forest and during the wet season, differences were not statistically significant suggesting that line-planting did not significantly affect amphibian diversity. The line-planted areas had a slightly higher, but not statistically significant diversity, richness, and evenness of tree species than the unplanted forest. Multi-response permutation procedure (MRPP) showed statistically significant community composition differences between line-planting and control plot trees (T = ?5.89, A = .86; p < .001). But mean similarity among plots in both the line-planted and control plots was relatively low at less than 50% of shared species, indicating high diversity of vegetation in the overall forest area. Canopy cover by tree species greater than 3 cm in dbh was much higher in the undisturbed forest but this difference may be reduced as the young line-planted hardwoods mature. Forest enrichment through line-planting of valuable timber species in secondary subtropical wet forest does not significantly affect tree diversity.     

A Genetic Study of Piglet Growth and Survival

The study analysed 954 Yorkshire sows from a research station in Sweden. The heritability for mean piglet weight at 3 weeks was 0.30 and the heritability for number dead up to 3 weeks was 0.09. Correlations showed that when the number of piglets born into a litter increased, it followed that each piglet weighed less at 3 weeks of age (genetic correlation -0.1). The higher the litter size at birth, the more piglets died, and if many piglets died in a litter, growth was low in the surviving piglets. The genetic correlation between mean birth weight and mean weight at 3 weeks was estimated to be 0.6.