Detection of equine herpesvirus-1 in nasal swabs of horses by quantitative real-time PCR

Background: Early identification of inhalation-transmitted equine herpesvirus type 1 (EHV-1) infections has been facilitated by the availability of a number of real-time quantitative PCR (qPCR) tests. A direct comparison between nasal swab qPCR and traditional virus isolation (VI) requires a method for normalizing the qPCR samples and controlling for PCR inhibitors present in some clinical samples.
Objectives: To quantify EHV-1 shedding in viral swabs using an internal control and to compare fast qPCR to VI for the detection of EHV-1 in nasal swabs from horses.
Animals: Fifteen horses experimentally infected with EHV-1.
Methods: Experimental study : Nasal swab samples were collected daily after experimental infection for up to 21 days. VI was performed by conventional methods. The DNA was prepared for qPCR with the addition of a known quantity DNA of Marek's disease virus as an internal control. qPCR was performed.
Results: The qPCR method detected virus up to day 21 after challenge, whereas VI detected virus only to day 5. The median Kaplan-Meier estimates for EHV-1 detection were 12 days for qPCR and 2 days for VI ( P < .0001). When compared with VI, the sensitivity and specificity of qPCR were 97 (95% CI: 86–100) and 27% (95% CI: 20–35).
Conclusions and Clinical Importance: We conclude that fast qPCR of nasal swab samples should be chosen for diagnosis and monitoring of herpesvirus-induced disease in horses. Recommended reference ranges of C _T values are provided as well as justification of a minimum 10-day quarantine period.     

Identification of quantitative trait Loci for resistance to southern leaf blight and days to anthesis in a maize recombinant inbred line population

ABSTRACT A recombinant inbred line population derived from a cross between the maize lines NC300 (resistant) and B104 (susceptible) was evaluated for resistance to southern leaf blight (SLB) disease caused by Cochliobolus heterostrophus race O and for days to anthesis in four environments (Clayton, NC, and Tifton, GA, in both 2004 and 2005). Entry mean and average genetic correlations between disease ratings in different environments were high (0.78 to 0.89 and 0.9, respectively) and the overall entry mean heritability for SLB resistance was 0.89. When weighted mean disease ratings were fitted to a model using multiple interval mapping, seven potential quantitative trait loci (QTL) were identified, the two strongest being on chromosomes 3 (bin 3.04) and 9 (bin 9.03-9.04). These QTL explained a combined 80% of the phenotypic variation for SLB resistance. Some time-point-specific SLB resistance QTL were also identified. There was no significant correlation between disease resistance and days to anthesis. Six putative QTL for time to anthesis were identified, none of which coincided with any SLB resistance QTL.     

Activated coagulation times in normal cats and dogs using MAX-ACTTM tubes

Objective  To establish reference values for activated coagulation time (ACT) in normal cats and dogs, by visual assessment of clot formation using the MAX-ACT^TM tube.
Subjects  We recruited 43 cats and 50 dogs for the study; 11 cats and 4 dogs were excluded from the statistical analysis because of abnormalities on clinical examination or laboratory testing including anaemia, prolonged prothrombin time (PT) or activated partial thromboplastin time (APTT), or insufficient plasma volume for comprehensive laboratory coagulation testing.
Procedure  Blood samples were collected via direct venipuncture for MAX-ACT, packed cell volume/total solids, manual platelet estimation and PT/APTT measurement. Blood (0.5 mL) was mixed gently in the MAX-ACT tube at 37°C for 30 s, then assessed for clot formation every 5 to 10 s by tipping the tube gently on its side and monitoring for magnet movement. The endpoint was defined as the magnet lodging in the clot. The technique was tested with 10 dogs by collecting two blood samples from the same needle insertion and running a MAX-ACT on each simultaneously.
Results  In normal cats the mean MAX-ACT was 66 s (range 55–85 s). In normal dogs the mean was 71 s (range 55–80 s). There was no statistical difference between the first and second samples collected from the same needle insertion.
Conclusions and Clinical Relevance  In both cats and dogs, a MAX-ACT result >85 s should be considered abnormal and further coagulation testing should be performed. Additionally, failure to discard the first few drops of the sample does not appear to significantly affect results.     

Ovulation timing. Concepts and controversies.

While the luteinizing hormone (LH) surge has long been accepted as the key event in the estrous cycle of the bitch, historically, there has been no practical way to identify it. In the past, the veterinary practitioner had to rely on general and/or subjective information received from vaginal cytology, physical examinations, and observations. With the recent development of in-clinic progesterone and LH assays, and the wider availability of laboratory quantitative progesterone assays, the LH surge can either be identified directly or estimated by the detection of changes in progesterone. As a result, ovulation time can now be predicted with high accuracy in a private practice setting.     

A functional hypothesis of the threat of local extirpation of woody plant species by elephant in Africa

An hypothesis predicting which woody species selected by elephant are at risk of local extirpation is based on an understanding of elephant digestive physiology, foraging ecology, attributes of individual plants and populations, and historical changes in ecosystems. Elephant select items rich in cell solubles relative to availability for achieving maximum throughput per unit time on account of their large energy requirement, hindgut fermentation with limited cell wall digestion, high passage rate, and inefficient recycling of microbial protein. Accordingly, diet is predominantly green grass and herbs in the wet season, green browse in the late wet and dry seasons, and bark and roots following leaf fall. Increased consumption of woody material indicates nutritional stress. Bulls graze more than cows and impact woody plants more when grazing deteriorates.Species vulnerable to extirpation by elephant are those: whose attributes predispose adults to pollarding, uprooting or ringbarking; adults coppice poorly, hence mortality occurs; mortality is not compensated by regeneration and recruitment owing to the impact of elephant and other agents; species have a restricted distribution; and poor dispersal ability constrains recolonisation. Threat of their local extirpation has increased because of an increased probability of encounter with elephant attributed to artificial boundaries that have constrained movement, and proliferation of water points that has reduced spatial refuges for plants and weakened density-dependent regulation of elephant populations. Degradation of grasslands, wetlands and riparian areas has forced elephant to subsist on woody vegetation for a longer period of the annual cycle. A reduction in water points should increase local elephant density and attendant density-dependent effects of increased foraging distance, nutritional stress, calf and juvenile mortality, and predation, and reduce reproduction. Eliminating human predation after 4000 years in some parks has contributed to the problem. Mitigation of the threat of local extirpation should concentrate on configuration of boundaries, water provision, simulated predation, minimum reserve size, and not pursue non-definable notions of elephant carrying capacity.     

How to grow a mind: statistics, structure, and abstraction

In coming to understand the world-in learning concepts, acquiring language, and grasping causal relations-our minds make inferences that appear to go far beyond the data available. How do we do it? This review describes recent approaches to reverse-engineering human learning and cognitive development and, in parallel, engineering more humanlike machine learning systems. Computational models that perform probabilistic inference over hierarchies of flexibly structured representations can address some of the deepest questions about the nature and origins of human thought: How does abstract knowledge guide learning and reasoning from sparse data? What forms does our knowledge take, across different domains and tasks? And how is that abstract knowledge itself acquired?     

Fissioning in planarians: control by the brain

Reduced population densities lead to increased rates of fissioning in planarians whereas higher population densities suppress fissioning. This effect is not primarily due to mucus deposition or substances secreted into the water. Experiments are presented which show a system of population feedback control. In the presence of other planarians, the brain exerts an influence (probably neurohormonal) to suppress fissioning. This influence becomes attenuated with axial distance from the brain.     

Antiradical properties of red wine portisins

The free radical chemistry of two polyphenolic pigments from red wine, belonging to the family of portisins, has been investigated after reaction with O(2)(?-) radicals using electron paramagnetic resonance (EPR) spectroscopy. Two portisins derived from malvidin-3-glucoside and cyanidin-3-glucoside were used for this study. Stable free radicals were detected with both portisins and correspond to unpaired electrons localized on the B as well as F rings of the portisins. Interpretations were confirmed by comparison with the spectra of free radicals formed by oxidation of the model compounds cyanidin-3-glucoside, malvidin-3-glucoside, and catechin. These results concur with previous work reporting the higher antiradical properties of these pigments compared to their anthocyanin precursors.