Pharmacokinetics of cefotaxime in sheep

Five healthy adult Merino ewes were each given 2 g of cefotaxime by the IV, IM, and subcutaneous (SC) routes. The serial plasma samples collected after each treatment were analyzed for cefotaxime by a new high-pressure liquid chromatographic method. Plasma concentration time profiles were characterized by a linear 2-compartment model after IV administration and the following mean values (+/- SD) were found: biological half-life, 23 +/- 8 minutes; apparent volume of distribution, 5.5 +/- 1.3 L; plasma clearance, 0.37 +/- 0.09 L/min; elimination rate constant, 0.066 +/- 0.014 minute-1; rate of diffusion into tissue, 0.013 +/- 0.013 minute-1; and out of tissue, 0.035 +/- 0.017 minute-1. Plasma cefotaxime concentrations in the ewes given the drug by the IV, IM, and SC routes were 113 +/- 32, 71 +/- 20, and 38 +/- 11 micrograms/ml, respectively, at 15 minutes; 2.31 +/- 0.82, 11.3 +/- 6.6, and 16.4 +/- 3.7 micrograms/ml at 120 minutes; and 1.05 +/- 1.22, 9.3 +/- 5.2, and 14.9 +/- 1.27 micrograms/ml at 150 minutes. After cefotaxime was given SC and IM, plasma values were higher for a longer time than they were after the drug was given IV, probably due to a slower release of drug from the former injection sites.     

CLINICAL ASSESSMENT OF RENAL FUNCTION IN THE DOG WITH A REDUCTION IN NEPHRON NUMBER*

The viewpoint presented is that, because compensatory functional adjustment of the residual nephrons occurs in chronic renal disease, reduction in nephron number usually exceeds 70% before a diagnosis is made. The case that earlier diagnoses are likely if laboratory medicine values are measured and interpreted with a maximum of efficiency is then made. The laboratory data more commonly used in practice for the clinical assessment of renal function in the dog are presented and some comparisons with findings in man are made. The information originates from clinical and experimental observations of the authors, as well as from a literature review. The laboratory data presented and discussed includes glomerular filtration rate and the clearance of nitrogenous waste (urea and creatinine), plasma protein concentration, plasma osmolality, renal concentrating capacity, and urinary constituents, particularly its protein concentration and sediment (centrifuge deposit). All parameters recommended for the clinical assessment of chronic renal failure are considered qualitatively, and some are also dealt with quantitatively.     

First detection of 'Candidatus Mycoplasma haemolamae' infection in alpacas in England

This is the first report of detection of Candidatus Mycoplasma haemolamae in alpacas in England. The primary case occurred in a three year-old male alpaca in the south-east of England which presented with a history of progressive weight loss, lethargy, swelling of the scrotum and pale mucous membranes. Blood smear examination revealed a moderate, regenerative anaemia, with numerous small basophilic coccoid structures consistent with Candidatus M haemolamae. To confirm the presence of Candidatus M haemolamae, a portion of the 16S rDNA gene was amplified and analysed by denaturing gradient gel electrophoresis (DGGE). 16S rDNA gene sequencing showed a 99.8 per cent homology with Candidatus M haemolamae sequences deposited in GenBank. Subsequently, a cross-sectional study was carried out to investigate the presence of Candidatus M haemolamae infection in the alpaca herd from which the primary case was detected (n=131). Blood smear examinations and PCR with DGGE were used and compared with a species-specific PCR. The prevalence of infection when PCR positive results were combined was 29 per cent. A substantial agreement between the PCR/DGGE and the species-specific PCR was found (κ=0.86). A significant association was also found between age and infection (P=0.04) while no significant association was found with sex or origin.     

Squamous cell carcinoma in a tuatara (Sphenodon punctatus)

CASE HISTORY: A mature male tuatara was presented with a history of recurrent cloacal prolapse.

CLINICAL AND PATHOLOGICAL FINDINGS: The prolapsed tissue included a 12 mm diameter mass, which histologically showed cords and nodules of neoplastic epithelial cells.

DIAGNOSIS: The mass was diagnosed as a squamous cell carcinoma with ulceration of the overlying stratified squamous epithelium and diffuse inflammation of the surrounding dermis.

CLINICAL RELEVANCE: This case presented a rare opportunity to investigate squamous cell carcinoma in a long-lived lower vertebrate species. Future recurrence or metastasis of the mass may add useful information to the current base of knowledge of the behaviour of malignant neoplasms in reptiles.