Seizures during medetomindine sedation and local anaesthesia in two dogs undergoing skin biopsy

Each of two dogs presented for multiple skin biopsies were sedated with intravenous medetomidine and lignocaine was injected subcutaneously to provide local anaesthesia for skin biopsy. One dog had a seizure during skin biopsy and again immediately following reversal of medetomidine with atipamezole. The other dog developed seizures 2 h following skin biopsy at which time the medetomidine was reversed with atipamezole. Both dogs were neurologically normal with no history of seizures prior to the procedure and remained neurologically normal for 14 weeks and 9 months, respectively, following the procedure. A drug interaction between the α₂-adrenergic agonist medetomidine and lignocaine is suspected and highlights the potential for seizures following the subcutaneous administration of relatively large doses of lignocaine under medetomidine sedation.     

Scrub-itch mite infestation in the endangered bridled nailtail wallaby

Skin lesions on the ears and inguinal and axillary regions of a number of adult animals within a captive population of the endangered bridled nailtail wallaby ( Onychogalea fraenata ) were associated with the trombiculid mite, Eutrombicula hirsti . The local inflammatory response of these Australian marsupials is described.     

Influence of wildfire severity on riparian plant community heterogeneity in an Idaho,USA wilderness

Despite the increasing recognition of riparian zones as important ecotones that link terrestrial and aquatic ecosystems and of fire as a critical natural disturbance, much remains unknown regarding the influence of fire on stream-riparian ecosystems. To further this understanding, we evaluated the effects of mixed severity wildfire on riparian plant community structure and composition in headwater streams of the Big Creek Watershed of the Frank Church ‘River of No Return’ Wilderness of central Idaho. Five years after a large stand-replacing fire, we conducted riparian vegetation surveys at sixteen reaches across a range of burn types. Non-metric Multidimensional Scaling (NMS) and Multi-Response Permutation Procedure (MRPP) analyses showed an overall shift in community composition and structure between vegetation at unburned and severely burned reaches. Although total plant cover was significantly less at severely burned areas, recovery of the deciduous understory was apparent. Severely burned reaches were characterized by a marked increase in cheatgrass (Bromus tectorum). Reaches that were exposed to low-severity fire were indistinguishable from unburned reaches relative to vegetation community composition and structure, pointing to a possible disturbance threshold that may need to be crossed in order to alter riparian plant communities.     

Using a GnRH agonist to obtain an index of testosterone secretory capacity in the cockatiel (Nymphicus hollandicus) and sulphur-crested cockatoo (Cacatua galerita)

Objective   Validation of a stimulation test for determining the steroidogenic capacity of the parrot testis. The major aim was to characterise testosterone secretion after injection of a gonadotropin-releasing hormone agonist (GnRHa), then use the test to investigate seasonal reproduction in the male cockatiel.
Procedure   A synthetic GnRHa (buserelin; 8.0 µg of peptide/kg bodyweight) was injected IM into male cockatiels (n = 7) and sulphur-crested cockatoos (n = 3) and serial blood samples collected at 0, 30, 60, 90 and 120 min after administration. Once validated, the technique was subsequently used to examine seasonal changes (23 months) in the testosterone profile of a captive cockatiel population.
Results   Injection of buserelin resulted in a significant increase in the testosterone concentration of cockatiel plasma, with maximal concentrations occurring at approximately 60 (1.33 ± 0.08 ng/mL) to 90 min (1.22 ± 0.08 ng/mL) after injection. Although no clear pattern of seasonal variation in testosterone secretion was detected in cockatiel plasma, samples taken 60 and 90 min after administration showed a significant increase in all seasons. Injection of buserelin in the sulphur-crested cockatoo also resulted in increased testosterone secretion, with maximal concentrations obtained after 90 min.
Conclusion   Buserelin can be used to obtain a reliable index of the prevailing testosterone capacity of the cockatiel and cockatoo testis. With further studies, this test may be incorporated into clinical assessment of reproductive status.     

Critical Loads of Acidity to Protect and Restore Acid-Sensitive Streams in Virginia and West Virginia

The purpose of the research described here is to apply a new approach for generating aquatic critical load (CL) and exceedance calculations for an important acid-sensitive region of the eastern USA. A widespread problem in regional aquatic acidification CL modeling for US ecosystems has been the lack of site-specific weathering data needed to derive accurate model CL estimates. A modified version of the steady-state water chemistry CL model was applied here to estimate CL and exceedances for streams throughout acid-sensitive portions of Virginia and West Virginia. A novel approach for estimating weathering across the regional landscape was applied, based on weathering estimates extracted from a well-tested, process-based watershed model of drainage water acid?Cbase chemistry and features of the landscape that are available as regional spatial data coverages. This process allowed extrapolation of site-specific weathering data from 92 stream watersheds to the regional context in three ecoregions for supporting CL calculations. Calculated CL values were frequently low, especially in the Blue Ridge ecoregion where one-third of the stream length had CL?<?50?meq/m²/year to maintain stream ANC at 50???eq/L under steady-state conditions. About half or more of the stream length in the study region was in exceedance of the CL for long-term aquatic resource protection under assumed nitrogen saturation at steady state. Land managers and air quality policy makers will need this information to better understand responses to air pollution emissions reductions and to develop ecoregion-specific air pollution targets.     

Ascorbic acid determination in processed potatoes

A method to determine ascorbic acid at any stage of potato processing was developed. Potato samples are frozen in dry ice, lyophilized and analyzed using a modified spectrophotometric method. This method is simple, accurate, inexpensive and has a detection limit of 1.2 mg ascorbic acid/100 g dry weight potatoes.