Caudal vena cava obstruction caused by redundant pacemaker lead in a dog

Inferior vena cava obstruction, a rare but serious complication of transvenous pacemaker lead placement in humans, has not been reported in dogs. We describe this complication in a dog that developed ascites 8 months after pacemaker implantation. Radiography disclosed a loop of redundant lead within the caudal vena cava (CVC), and angiography demonstrated obstruction to blood flow. Withdrawal of the loop from the CVC did not restore blood flow. Persistent obstruction was suspected secondary to fibrosis resulting from vascular damage caused by the loop of lead. Angioplasty of the CVC obstruction restored blood flow and resolved the dog's clinical signs.     

Adenylate cyclases of Trypanosoma brucei inhibit the innate immune response of the host

The parasite Trypanosoma brucei possesses a large family of transmembrane receptor-like adenylate cyclases. Activation of these enzymes requires the dimerization of the catalytic domain and typically occurs under stress. Using a dominant-negative strategy, we found that reducing adenylate cyclase activity by about 50% allowed trypanosome growth but reduced the parasite's ability to control the early innate immune defense of the host. Specifically, activation of trypanosome adenylate cyclase resulting from parasite phagocytosis by liver myeloid cells inhibited the synthesis of the trypanosome-controlling cytokine tumor necrosis factor-α through activation of protein kinase A in these cells. Thus, adenylate cyclase activity of lyzed trypanosomes favors early host colonization by live parasites. The role of adenylate cyclases at the host-parasite interface could explain the expansion and polymorphism of this gene family.     

A mechanistic model of whole-tract digestion and methanogenesis in the lactating dairy cow: model development, evaluation, and application.

Dietary intervention to reduce methane emissions from lactating dairy cattle is both environmentally and nutritionally desirable due to the importance of methane as a causative agent in global warming and as a significant loss of feed energy. Reliable prediction systems for methane production over a range of dietary inputs could be used to develop novel dietary regimes for the limitation of feed energy loss to methane. This investigation builds on previous attempts at modeling methanogenesis and involves the development of a dynamic mechanistic model of wholerumen function. The model incorporates modifications to certain ruminal fermentation parameters and the addition of a postruminal digestive element. Regression analysis showed good agreement between observed and predicted results for experimental data taken from the literature (r2 = 0.76, root mean square prediction error = 15.4%). Evaluation of model predictions for experimental observations from five calorimetry studies (67 observations) with lactating dairy cows at the Centre for Dairy Research, in Reading, U.K., shows an underprediction (2.1 MJ/d) of methane production (r2 = 0.46, root mean square prediction error = 12.4%). Application of the model to develop diets for minimizing methanogenesis indicated a need to limit the ratio of lipogenic to glucogenic VFA in the rumen and hindgut. This may be achieved by replacing soluble sugars in the concentrate with starch or substituting corn silage for grass silage. On a herd basis, the model predicted that increasing dietary energy intake per cow can minimize the annual loss of feed energy through methane production. The mechanistic model is a valuable tool for predicting methane emissions from dairy cows.     

Effect of organic fertilizer on the growth and fruit yield of six paprika (<Emphasis Type="Italic">Capsicum annum</Emphasis> L.<Emphasis Type="Italic">)</Emphasis> cultivars in Malawi

The production of paprika (Capsicum annum L.) under small-scale farm conditions in southern Africa is constrained by low soil fertility and lack of appropriate cultivars. The objective of this study was to determine the growth responses and fruit yields of six cultivars of paprika to organic and inorganic nutrient sources. The study was conducted in 2007 and 2008 at Chitedze Agricultural Research Station in Malawi. A combination of six paprika cultivars and four nutrient sources, namely (1) organic input from Gliricidia, (Gliricidia sepium) biomass, (2) inorganic fertilizer, (3) integrated nutrient input (Gliricidia biomass + inorganic fertilizer), and (4) control (no nutrient input) were compared. Each combination was replicated five times. A split-plot design was used where nutrient sources formed the main plot and cultivars the sub-plots. Plant height differed due to nutrient source in 2007 and 2008, while differences due to cultivar were minor. The control plots produced the shortest plants (height < 50 cm), while plots receiving the integrated nutrient input produced the tallest plants (height > 60 cm). Numbers of branches and fruits per plant differed due to nutrient source and cultivar during most of the study period. Plants receiving either organic inputs (Gliricidia biomass) alone or the integrated nutrient input alone had significantly higher stem, leaf and fruit weight compared with the control. Average fruit yield was lower in control plots than in plots receiving the organic input alone or the integrated nutrient input. Among cultivars, Papri-King, Papri-Supreme and Papri-Queen produced higher dry fruit yield. The ASTA and RAL colour rating was within the internationally accepted range for fruit from the treatments.     

Growth and N nutrition, monitored by enzyme assays, in a hardwood plantation: effects of mulching materials and glyphosate application

The effects of mulching materials (black plastic and straw) and herbicide application (glyphosate) on growth and nitrogen nutrition of butternut (Juglans cinerea), white ash (Fraxinus americana) and bur oak (Quercus macrocarpa) were studied in a plantation established in an abandoned field in southern Québec (Canada) since 1987. To ascertain the efficiency of mulching materials on the performance of tree seedlings, a herbicide (glyphosate, 6 l ha⁻¹) was applied in half of the experimental plots in June 1990 and 1991. Soil parameters (temperature, moisture) and soil nitrate and ammonium concentrations were measured during the growing season in 1991. In summer 1991, nitrogen nutrition of the seedlings was monitored using enzyme assays (nitrate reductase activity (NRA), glutamine synthetase activity (GSA)) of the leaves of the three deciduous tree species. Mulching affected soil parameters, with black plastic producing the highest soil temperature (23.4°C) and straw the highest soil moisture (183.6 g kg⁻¹) in June. NRA varied in relation to tree species, herbicide application, mulching material and time. GSA was poorly correlated to silvicultural treatments. Butternut showed the highest NRA, especially in herbicide plots irrespective of mulching material. Bur oak NRA showed less variation between herbicide and non-herbicide plots and reacted more to the mulching treatments. White ash NRA only showed an herbicide effect in June. All species reacted positively to the addition of an herbicide around the mulching material, but not to the same degree. Height and diameter increment ratios (with/without glyphosate application) indicate that butternut growth was the most improved by herbicide applications, followed by white ash and bur oak. This indicates that the effectiveness of mulching alone decreases in the following order: bur oak > white ash > butternut. The utilization of mulching material in abandoned fields as an alternative to herbicide application is closely linked to the species chosen. Enzyme assays (NRA) were shown to be a valuable tool for monitoring physiological status of planted trees subjected to environmental changes brought on by silvicultural practices.     

Brownfield regeneration to greenspace: Delivery of project objectives for social and environmental gain

In Europe and North America regeneration of brownfield land is an important objective of government policy. Regeneration to greenspace in particular, has been used to help reverse social and environmental decline, with typical benefits including increased flood retention capacity, temperature regulation, habitat for wildlife, building communities, encouraging local engagement and providing space for play and recreation.Regeneration project objectives are set to maximise the benefits of greenspace creation for a given location; setting the right objectives is critical to lever funding required to pump-prime activity. However, opportunities to heighten benefits delivered through the process of regeneration can be overlooked. This research identified that there was a disconnect between practices required to meet the defined objectives for a specific site and regeneration activity. This was often due to gaps in the project delivery plans: tasks which are important to realise improvement were missing. Emphasis was often found to be on site delivery, with a benign assumption that the benefits will arise as a result of project completion. Although there are some examples of practices to optimise benefits, a lack of consistency indicates scope for improvement.A logic model was co-produced with practitioners in a bid to address this issue and support project delivery planning. The model maps the social and environmental objectives for a site against specific project delivery stages. The model was refined through a workshop exercise involving discussion with practitioners who were planning new urban greenspaces on brownfield land.This paper presents the logic model to demonstrate what needs to be considered to improve the project delivery planning process, signposting the steps required to translate project objectives into outcomes, to optimise social and environmental benefits delivered during and after regeneration. The model could support those involved in project delivery planning and help raise the overall quality of new greenspace.     

Soil aggregation in a laboratory experiment: Interactions between earthworms, woodlice and litter palatability

Interactions between soil invertebrate functional groups are still poorly understood. In this study, the effect of the soil dwelling earthworm Aporrectodea caliginosa and the woodlouse Porcellio scaber (litter inhabitant), alone or in combination, on soil aggregation was investigated in laboratory microcosms with litter of different quality (Quercus robur and Fagus sylvatica). After 4 months of incubation, the aggregate size distribution was measured using a dry-sieving method. A. caliginosa played an important role in the formation of large aggregates (>2 mm), whereas P. scaber greatly influenced litter disappearance. A. caliginosa individuals formed a greater number of large aggregates when fed with beech leaves compared to oak leaves even though they preferred the latter. In the presence of beech and P. scaber, A. caliginosa produced significantly fewer large aggregates than expected.     

Prednisolone-responsive neuropathy in a cat

Chronic relapsing polyneuropathy was diagnosed in a 15-month-old cat with a 12-week history of limb weakness. The clinical course was punctuated by spontaneous remissions and relapse. There were two striking physical findings, weak withdrawal reflexes and atrophy of the proximal and distal limb muscles. Electrophysiological findings typical of a demyelinating motor neuropathy were present, namely small, dispersed compound muscle action potentials, markedly slow motor conduction and denervation potentials that were more prominent dis-tally. Muscle biopsies showed changes consistent with denervation and a paucity of myelinated axons in intramuscular nerve bundles. The neuropathy responded rapidly and completely to prednisolone administration, which was slowly tapered over several months.