NHLRC1 repeat expansion in two beagles with Lafora disease

Lafora disease is a fatal genetic disorder characterised by neurotoxic deposits of malformed insoluble glycogen. In humans it is caused by mutation in the EPM2A or NHLRC1 genes. There is a known mutation in miniature wirehaired dachshunds which has not been documented in other dog breeds, including beagles, in which the disease is relatively commonly reported. This case report describes the causative defect in two affected beagles, namely the same massive expansion as in miniature wirehaired dachshunds of a 12‐nucleotide repeat sequence that is unique to the canine NHLRC1 gene. This is the first mutation described in beagles with Lafora disease, and so far the only Lafora disease genetic variant in dogs.     

Quadricuspid aortic valve and associated abnormalities in a dog

An 11-month-old, female Scottish terrier was presented with a history of a heart murmur. The electrocardiogram showed signs of left ventricular enlargement, and radiography confirmed generalized cardiomegaly. Echocardiography revealed four equally sized aortic valve cusps. A ventricular septal defect, with systolic left-to-right shunting, and aortic regurgitation into both ventricles were also present. The dog was free of clinical signs 1 year after diagnosis.     

Neuronal population coding of movement direction

Although individual neurons in the arm area of the primate motor cortex are only broadly tuned to a particular direction in three-dimensional space, the animal can very precisely control the movement of its arm. The direction of movement was found to be uniquely predicted by the action of a population of motor cortical neurons. When individual cells were represented as vectors that make weighted contributions along the axis of their preferred direction (according to changes in their activity during the movement under consideration) the resulting vector sum of all cell vectors (population vector) was in a direction congruent with the direction of movement. This population vector can be monitored during various tasks, and similar measures in other neuronal populations could be of heuristic value where there is a neural representation of variables with vectorial attributes.     

The diagnosis and management of snakebite in dogs--a southern African perspective

Cases of snakebite envenomation are frequently presented to veterinary practitioners in southern Africa. Despite this, no published guidelines exist on how this medical emergency should be managed. Southern African snake venoms can be classified into 3 main types based on the main mechanism of venom action and clinical presentation. A polyvalent antivenom is manufactured in South Africa and contains antibodies against the most important southern African snake venoms. The cytotoxic venoms are represented mainly by the puff-adder (Bitis arietans), Mozambique spitting cobra (Naja mossabica), black-necked spitting cobra (Naja nigricollis) (in the Western Cape and Namibia) and the stiletto snake (Atractaspis bibronii). These venoms may cause dramatic local swelling, high morbidity and low mortality and infrequently require the use of antivenom for survival (the only cytotoxic venoms used to prepare the antivenom are the puff-adder and Mozambique spitting cobra). The neurotoxic venoms (represented chiefly by the non-spitting cobras and mambas) cause high mortality due to rapid onset of paresis and require antivenom and mechanical ventilatory support which is life-saving. The boomslang (Dispholidus typus) and the vine snake (coagulopathic venom) rarely bite humans but dogs may be bitten more frequently. These venoms cause a consumption coagulopathy and successful treatment of boomslang bites requires the use of snake species-specific monovalent antivenom. There is no antivenom available for treating vine snake (Thelotornis capensis), berg adder (Bitis atropos), night adder (Causus spp.), stiletto snake and other lesser adder bites. There are some important differences between the way snakebites are managed in humans and dogs.     

Intraosseous regional perfusion for treatment of septic physitis in a two-week-old foal

A 2-week-old Morgan filly examined because of lameness of 5 days' duration was found, on the basis of clinical and radiographic findings, to have septic physitis of the distal end of the radius. The foal was treated by means of intraosseous regional perfusion with penicillin and amikacin and systemic administration of antimicrobials. Intraosseous regional perfusion was performed 3 times. The foal was anesthetized for the first episode of intraosseous regional perfusion, but was only sedated for the subsequent 2 episodes. Antimicrobials were administered systemically for 22 days. Foals with septic physitis are typically considered to have a guarded to poor prognosis for recovery; however, this treatment regimen resulted in relatively fast and uncomplicated resolution of the infection in this foal.     

The effects of diminazene aceturate on systemic blood pressure in clinically healthy adult dogs

Diminazene aceturate is a commonly used antibabesial agent. It has been postulated that diminazine may induce a decrease in blood pressure and exacerbate the hypotension presented in dogs with babesiosis. This study was undertaken to assess the effect of diminazine aceturate on the blood pressure of healthy dogs. Six healthy German shepherd dogs between 18 and 24 months of age with a mean weight of 30.4 +/- 2.75 kg were used. Blood pressure was directly measured at the following time intervals: -5, 0, 5, 10, 15, 20, 25, 30, 35, 40, 50, 60, 90 and 120 minutes after treatment with diminazine aceturate (4.2 mg/kg) intramuscularly. No statistical difference (P > 0.05) was found in blood pressure between any of the time intervals. An increase in heart rate was seen 5 minutes after the administration of diminazine aceturate but no change in blood pressure was evident. This study concluded that diminazene aceturate in its current formulation with antipyrine does not alter blood pressure in healthy adult dogs.     

Spin selectivity in electron transmission through self-assembled monolayers of double-stranded DNA

In electron-transfer processes, spin effects normally are seen either in magnetic materials or in systems containing heavy atoms that facilitate spin-orbit coupling. We report spin-selective transmission of electrons through self-assembled monolayers of double-stranded DNA on gold. By directly measuring the spin of the transmitted electrons with a Mott polarimeter, we found spin polarizations exceeding 60% at room temperature. The spin-polarized photoelectrons were observed even when the photoelectrons were generated with unpolarized light. The observed spin selectivity at room temperature was extremely high as compared with other known spin filters. The spin filtration efficiency depended on the length of the DNA in the monolayer and its organization.     

Aortic foreign body (airgun pellet) embolism in a cat

A five-year-old female domestic shorthair cat presented with clinical signs typical of an aortic saddle thromboembolism. An echocardiogram and thoracic radiographs excluded cardiac disease as a source of the thrombus. Two heavy metal opacity, pellet-like objects were seen in the thoracic and abdominal radiographs. Abdominal ultrasound demonstrated occlusion of aortic blood flow by the abdominal pellet but could not indicate whether this was due to a penetrating aortic wound or pellet embolisation. A necropsy confirmed a penetrating left ventricular cardiac wound with subsequent embolisation of the pellet to the abdominal aorta.     

Thrombocytopaenia in canine babesiosis and its clinical usefulness

Canine babesiosis is a common cause of thrombocytopaenia but there are few formal studies that have investigated this haematological finding in dogs. Thrombocyte counts from full blood counts were retrospectively analysed for the years 1996-2002. Thrombocyte counts and mean platelet volumes of dogs with babesiosis were compared with those of dogs, seen over the same period of time, that did not have babesiosis. There were 1162 cases in the Babesiosis group and 10 808 in the Non-babesiosis group. A frequency distribution of the thrombocyte counts showed a trimodal distribution in the Non-babesiosis group compared to a bimodal distribution in the Babesiosis group, with a strong positive skewness. The modes for the frequency distributions were 10, 40, 300 and 10, 35 x 10(9)/l thrombocytes, respectively. The median thrombocyte count in the Babesiosis group was 14 x 10(9)/l and 282 x 10(9)/l in the Non-babesiosis group. There was a statistically significant difference in the median thrombocyte count between the Babesiosis group and the Non-babesiosis group. In the Babesiosis group, 99% of the thrombocyte counts were below the lower reference range value (250 x 10(9)/l) and 62% of thrombocyte counts were below 25 x 10(9)/l. The mean platelet volume (11.1 fl) for the Babesiosis group was greater than the reference range (6-10 fl) and significantly larger than in the Non-babesiosis group (median 9.7 fl). Thrombocyte counts greater than 110 and 250 x 10(9)/l had a predictive value that the dog was not suffering from babesiosis of 99.3% and 99.8%, respectively. There was a statistically significant difference between the thrombocyte counts of dogs with babesiosis when grouped by parasitaemia scores. The mechanisms of the thrombocytopaenia are not fully understood, and multiple mechanisms, including concomitant thrombocytopaenia-inducing diseases such as ehrlichiosis, probably result in this haematological finding. Babesiosis in the South African canine population is associated with thrombocytopaenia in nearly all patients and is severe in the majority of them. In the absence of thrombocytopaenia, babesiosis is an unlikely diagnosis.