Pharmacokinetics of lithium in sheep

Lithium was administered to adult sheep to estimate its pharmacokinetic parameters and a suitable dosage for chronic psychopharmacological experiments. The triexponential decline of plasma lithium levels was tentatively interpreted with a three-compartment, open-model of distribution. Sheep differed from other species by the following features: high faecal excretion of lithium, recycling of lithium through the salivary secretion and low absorption rate of the orally-administered drug. A chronic oral administration of 1 mmol/kg once daily provided minimal plasma levels of about 1 mmol/l, without toxic side-effects. The results are discussed with respect to comparative pharmacokinetics of lithium and its potential use in the treatment of behavioral disorders of farm animals.     

The effect of flurbiprofen, a potent non-steroidal anti-inflammatory agent, upon Trypanosoma vivax infection in goats

Platelet aggregation leading to a decreased number of thrombocytes and reduced blood serotonin levels can be correlated with parasitaemia as has been observed in goats and cattle infected with T. vivax Y58. Flurbiprofen is a potent anti-inflammatory agent with antipyretic activity. In vitro , this agent inhibits platelet aggregation and blocks serotonin release. The results of the present study demonstrated that flurbiprofen inhibited the febrile reactions during the acute phase of T. vivax infection, but the drug did not prevent or reverse the associated drop in blood serotonin level during this period. Moreover, it was apparent that flurbiprofen had a deleterious effect on goats infected with T. vivax Y58. The infection in the untreated animals (sixteen out of seventeen goats) followed a rather mild and prolonged course with peaks of parasitaemia during the febrile episodes, whereas in flurbiprofen-treated goats (five animals), inoculated with the same number of trypanosomes, the parasitaemia was progressive and terminated in early death with disseminated intravascular coagulation at post mortem examination. These observations would seem to confirm the work of previous investigators, suggesting that anti-inflammatory agents have an aggravatory effect on the course of infection in animals inoculated with various strains of trypanosomes. Important differences exist, however, in the relationship between prostaglandin synthesis in the platelets of the goat and in those of other species.     

RADIOGRAPHIC AND ULTRASONOGRAPHIC EVALUATION OF THE PATELLAR LIGAMENT FOLLOWING TIBIAL PLATEAU LEVELING OSTEOTOMY

Objective evaluation of patellar ligament changes following tibial plateau leveling osteotomy (TPLO) for cranial cruciate ligament injury has not been published to date. In this study, the patellar ligament was evaluated using radiographs and high-resolution ultrasound in 31 stifles (29 dogs) preoperatively and at 1 month (n=31), 2 months (n=18), and 6 months (n=13) postTPLO. A ratio of the thickness of the proximal to distal patellar ligament was determined for all radiographs evaluated. Ultrasound evaluation included proximal, middle, and distal mid-sagittal thickness and transverse thickness, and transverse area measurements. Subjective grading (0 being normal through a scale of 3) of the ultrasound changes was also performed at each evaluation. Significant thickening of the distal patellar ligament was noted postoperatively as evidenced by thickness and area measurements and a decreased radiographic ratio (P < 0.01). Preoperative patellar ligament thickness and area were similar at the proximal, middle and distal sites. Ultrasound-derived thickness and area measurements of the distal patellar ligament were increased at 1 and 2 months (P < 0.01). The radiographic ratio was significantly decreased at 1, 2 and 6 months (P < 0.01). Subjectively, all patellar ligaments scored a 0 preoperatively and 16/31 received a score of 2 or 3 during follow-up evaluation. Additionally, these dogs had ultrasonographic and radiographic changes consistent with distal patellar ligament thickening. Body weight (kg) and postoperative TPLO angle had a significant influence on 1-month postoperative distal patellar ligament area using a stepwise logistic model (P < 0.05). Patellar ligament desmitis is a common postoperative sequela to the TPLO procedure, however its clinical significance (i.e., correlation with a residual lameness) was not evaluated in this study.     

The effects of equine skin preparation on transdermal drug penetration in vitro

An increasing number of formulations are applied to equine skin, yet variable penetration can affect efficacy, or the incidence of adverse effects, or both. To investigate the effects of common methods of skin preparation on transdermal drug penetration in vitro, we clipped, harvested, and froze skin samples from 5 Thoroughbred geldings. Thawed samples were prepared as follows: control (no preparation); cleaned with aqueous chlorhexidine (Aq-C, 0.1% w/v); cleaned with alcoholic chlorhexidine (Al-C, 0.5% w/v); shaved (Sh); or tape-stripped (Ta) with the use of adhesive tape. The samples were then placed in diffusion cells, and 2 g of methylsalicylate (MeSa) gel (Dencorub) was applied to the stratum corneum side. The penetration of MeSa and its analyte, salicylate (Sa), through the skin samples was measured over 10 h. Compared with control skin, significantly more MeSa penetrated through skin prepared with Al-C or Sh (P < 0.01) or with Aq-C or Ta (P < 0.05), and significantly more Sa was recovered in the receptor phase from skin prepared with Aq-C, Al-C, or Sh (P < 0.05) or with Ta (P < 0.01). A significantly higher rate of penetration and shorter lag time were also noted for MeSa with all the prepared skin samples, compared with the control samples. The results show that clinical techniques routinely used to clean or prepare skin can significantly affect the rate and extent of penetration of a topically applied drug. This may result in greater systemic availability of active drug, which could lead to enhanced efficacy and, possibly, a higher incidence of adverse effects.     

MAGNETIC RESONANCE IMAGING IN THE DIAGNOSIS OF CANINE INFLAMMATORY MYOPATHIES IN THREE DOGS

In humans affected with inflammatory myopathies, regions of altered signal intensity are found on magnetic resonance (MR) images of affected muscles. Although electromyography (EMG) is more practical for muscle disease evaluation, and a muscle biopsy is the only manner in which a definitive diagnosis can be made, MR imaging has proven useful if a specific anatomic localization is difficult to achieve. Three dogs with focal inflammatory myopathy diagnosed with the assistance of MR imaging are discussed and the findings are compared with those found in humans. MR images of the affected muscles in each dog were characterized by diffuse and poorly marginated abnormal signal on T1- and T2-weighted images. Marked enhancement was noted in these muscles after contrast medium administration. An inflammatory myopathy was confirmed histologically in all three dogs. A good association existed between the MR images and muscle inflammation identified histopathologically. MR imaging may be a useful adjunctive procedure for canine inflammatory myopathies.     

The potential of oral vaccines for disease control in wildlife species

Numerous infectious diseases caused by bacteria or viruses persist in developed and developing countries due to ongoing transmission among wildlife reservoir species. Such diseases become the target of control and management programmes in cases where they represent a threat to public health (for example rabies, sylvatic plague, Lyme disease), or livestock production (for example bovine tuberculosis, brucellosis, pseudorabies), or where they threaten the survival of endangered animal populations. In the majority of cases, lethal control operations are neither economically feasible nor publicly supported as a practical means for disease management. Prophylactic vaccination has emerged over the last 15 years as an alternative control strategy for wildlife diseases, mainly driven by the success of widescale oral rabies vaccination programmes for meso-carnivores in North America and Northern Europe. Different methods have been trialled for the effective delivery of wildlife vaccines in the field, however oral vaccination remains the most widely used approach. Successful implementation of an oral wildlife vaccine is dependent on a combination of three components: an efficacious immunogen, a suitable delivery vehicle, and a species-specific bait. This review outlines the major wildlife disease problems for which oral vaccination is currently under consideration as a disease management tool, and also focuses on the technological challenges that face wildlife vaccine development. The major conclusion is that attenuated or recombinant live microbes represent the most widely-used vaccines that can be delivered by the oral route; this in turn places major emphasis on effective delivery systems (to maintain vaccine viability), and on selective baiting systems, as the keys to wildlife vaccine success. Oral vaccination is a valuable adjunct or alternative strategy to culling for the control of diseases which persist in wildlife reservoirs.     

高寒地区施肥对短芒老芒麦草产量和种子产量的影响(简报)

短芒老芒麦(Elymus breviaristatus Keng)是禾本科披碱草属多年生疏丛型牧草,属上繁草,适于刈割利用.因其分蘖力强,耐寒,叶量丰富,产草量高且草质柔软,是高寒牧区人工草地的优势草种.