Short-term biological variation of clinical chemical values in Dumeril's monitors (Varanus dumerili).

Plasma biochemical values are routinely used in the medical management of ill reptiles, and for monitoring the health of clinically normal animals. Laboratory tests, including clinical biochemical values, are subject to biological and analytical variation, the magnitude of which determines the utility of population-based reference ranges for the detection of abnormal results in the individual animal. Nested analysis of variance of repeated measurements allows the variance to be broken into within-individual, between-individual, and analytical variation. When the within-individual variation is large and the interindividual variation is low, a sample may be accurately classified as normal or abnormal based on a population-based reference interval. However, if the intraindividual variation is low and the interindividual variation high, population-based reference intervals are of limited value as the ranges for an individual encompass only a part of the conventional reference interval. Between-lizard, within-lizard, and analytical components of variance were assessed by nested analysis of variance for 16 commonly measured plasma biochemical parameters in eight healthy adult Dumeril's monitors (Varanus dumerili). Albumin, cholesterol, phosphate, calcium, sodium, and total protein demonstrated levels of individuality suggesting that comparison of a single measurement to a conventional population-based reference range may be too insensitive to detect small but significant alterations in the value for that animal. Only for potassium and AST did the index of individuality suggest that the use of reference values may be warranted. Uric acid, globulin, glucose, and amylase fell in a gray zone, where population-based ranges should be used with caution. The critical difference indicates the difference between two consecutive analytical results that may be safely ascribed to natural variation. In the present study critical difference varied from 7 and 11%, respectively, for sodium and chloride to 75 and 125% for uric acid and AST.     

Physiological and biochemical consequences of electroimobilisation in conscious sheep

An electroimmobilisation device has been developed to facilitate the automated shearing of sheep, but there is little information on its effects on the body. We have studied its effects on the cardiovascular system and on intermediary metabolism in sheep. Electroimmobilisation caused statistically significant increases in mean arterial pressure, heart rate, cardiac output, renal and hepatic and hindquarter glucose and lactate flux, organ and whole body oxygen flux, hindquarter blood flow and core temperature and decreases in arterial and posterior vena cava blood pH, renal and hepatic blood flow and PaCO2. Notably, no change occurred in PaO2. The metabolic changes demonstrated the capacity of sheep to respond to the increased muscular and cardiovascular work induced by electroimmobilisation. Pulmonary function was not compromised during electroimmobilisation as judged from blood gas changes, and the acid/base changes were rapidly reversed after electroimmobilisation. The recovery to control conditions for all perturbations generally took no longer than 30 min, consistent with a rapid and physiologically adequate reversal by the animal's homeostatic mechanisms.     

Mycobacterial disease in a population of 339 cats in Great Britain: II. Histopathology of 225 cases, and treatment and outcome of 184 cases

This study investigated 339 cases of feline mycobacterial infection, with histopathology findings from 225 cases, and treatment and outcome information from 184 cases. Tissue samples from cats with cutaneous lesions or suspicious masses at exploratory laparotomy were submitted to the Veterinary Laboratories Agency for mycobacterial culture over a 4-year period to December 2008. The study reviewed the files for information about histopathology, treatment and outcome, and blindly reviewed histopathological changes (including staining for acid-fast bacteria [AFB]) in a sub-set of 45 cases. When a cat is suspected of having a mycobacterial infection, accurate identification of the species involved helps to determine possible treatment options and prognosis. The study confirmed that histopathology and the presence of AFB are useful tools in the recognition of mycobacterial infection. Unfortunately, they did little to help determine the species of mycobacteria involved. The study identified a group of cats that were negative for AFB at the primary laboratory, but from which mycobacteria could be cultured; commonly Mycobacterium bovis or Mycobacterium microti. The study also identified a group of cats which where culture negative, despite typical signs of mycobacterial infection and positive AFB staining. Many cases responded favourably to treatment (56% of the cases where information was available), and many cats gained complete remission (42%). However, relapses were common (64%) and often followed by pulmonary and/or systemic spread that may have resulted from treatment with short courses of single drugs. This study shows that the diagnosis and treatment of feline mycobacteriosis is complex and challenging.     

Possible parachordoma in a dog

Abstract

CASE HISTORY: A 15-mm diameter mass developed in the S/C tissue overlying the right lateral gluteal muscle of a 6½-year-old female Flat-coated Retriever.

PATHOLOGICAL FINDINGS: Cytological preparations following aspiration of the mass were highly cellular and consisted of a population of large polygonal cells containing single to multiple nuclei, large prominent nucleoli, and intracytoplasmic vacuoles. Histologically, the neoplasm consisted of similar large cells surrounded by thick fibrous connective tissue trabeculae. The large polygonal cells reacted positively with antibodies against vimentin, low- and high-molecular-weight variants of cytokeratin (AE1/AE3), but not with antibodies to desmin or glial fibrillary acidic protein (GFAP).

DIAGNOSIS: The clinical, gross, histological and immunohistochemical findings are similar to those reported for parachordomas in humans. Neither recurrence nor metastases were noted 18 months after surgical excision of the mass.

CLINICAL RELEVANCE: This is the first reported case of a possible parachordoma in a dog, a benign tumour with cytological features of malignancy.     

Comparison of a standard and a detailed postmortem protocol for detecting Mycobacterium bovis in badgers

A standard postmortem protocol, consisting of gross pathology, culture for mycobacteria and limited selective histopathology, was used in the randomised badger culling trial in Great Britain to detect Mycobacterium bovis infection. This standard protocol was compared with a more detailed protocol in which more tissues were examined grossly, more tissues were cultured, more culture slopes were seeded, the culture period was extended and tissues were examined routinely by histopathology. The standard protocol was more sensitive in badgers with gross visible lesions than in badgers with no gross visible lesions. When applied to the study population of badgers, the overall sensitivity of the standard protocol relative to the more detailed protocol was estimated to be 54.6 per cent (95 per cent confidence interval 44.9 to 69.8 per cent). Badgers with tuberculosis (tb) detected by the standard protocol had a mean of 7.6 tissues with microscopic lesions suspicious of tb. The additional badgers detected by the detailed protocol had a mean of 4.4 tissues with microscopic lesions suspicious of tb.     

Anesthetic management of a white rhinoceros (Ceratotherium simum) undergoing an emergency exploratory celiotomy for colic

ObservationsA 26-year-old male white rhinoceros (Ceratotherium simum), weighing approximately 2000 kg was anesthetized for an exploratory celiotomy. Sedation was achieved with intramuscular butorphanol (0.04 mg kg^?1) and detomidine (0.025 mg kg^?1) and induction of anesthesia with intravenous glyceryl guaiacolate (50 g) and three intravenous boluses of ketamine (200 mg, each); the trachea was then intubated and anesthesia maintained with isoflurane in oxygen using a circle breathing system. Positioning in dorsal recumbency for the surgery and later in sternal recumbency for the recovery represented challenges that added to the prolonged anesthesia time and surgical approach to partially correct an impaction. The rhinoceros recovered uneventfully after 10.4 hours of recumbency.ConclusionsAnesthetic management for an exploratory celiotomy with a midline approach is possible in rhinoceroses, although planning and extensive staff support is necessary to adequately position the patient.