Rapid quantification of ionophores in feeds by liquid chromatography-tandem mass spectrometry.

Ionophores are widely used in veterinary medicine as coccidiostats and for improving nutrient utilization in livestock production. Because of widespread use, ionophores sometimes cause poisoning in livestock. Quantifying concentration of these compounds in feeds for diagnostic purposes is needed.

Pancreatic atrophy due to zinc toxicosis in two African ostriches (Struthio camelus).

Two of three captive adult African ostriches exhibited inappetance and weakness. In spite of treatment, the two birds were euthanized because of lack of clinical improvement. Postmortem examination demonstrated exocrine pancreatic degeneration, necrosis, and atrophy.

Rapid and reliable identification of ionophore antibiotics in feeds by liquid chromatography-tandem mass spectrometry.

Veterinary diagnostic laboratories are constantly required to be innovative to develop quick, reliable, and cost-effective methods for use in diagnosis of intoxications. Livestock intoxication with ionophore antibiotics is sometimes encountered. A rapid qualitative method based on liquid chromatography-tandem mass spectrometry was developed to screen for the presence of monensin, lasalocid, salinomycin, and narasin antibiotics in feeds.

Standardized protocols for plasma clearance of iohexol are not appropriate for determination of glomerular filtration rates in anesthetized California sea lions (Zalophus californianus).

Abstract: Plasma clearance of iohexol was evaluated in eight anesthetized California sea lions (Zalophus californianus), without evidence of renal dysfunction, to determine if the one-compartment model and the sample protocol used in dogs and cats could be applied to this species. Nonlinearity between samples in 75% (6/8) of sea lions voided those results. An additional two anesthetized sea lions were sampled at 5, 30, 45, 60, 120, 180, 240, and 360 min post iohexol injection and semi-logarithmic curves calculated.

Health evaluation of free-ranging Humboldt penguins (Spheniscus humboldti) in Peru.

As part of ongoing ecological studies of Humboldt penguins (Spheniscus humboldti) at Punta San Juan, Ica Department, Peru, health surveys were conducted in November 1992, 1993, and 1994. In the three surveys, 98 birds in total were handled for examination, and blood was collected for laboratory analysis from 90 of these birds. All birds seemed to be in good condition.

Utility of high-performance liquid chromatography in the characterization of iatrogenic sodium diatrizoate-induced seizures in a horse.

Diagnostic evaluation of a mildly ataxic young gelding Quarterhorse included a contrast myelogram. Unfortunately, sodium diatrizoate was inappropriately administered by intrathecal injection resulting in severe unrelenting seizure activity and necessitated the destruction of the animal. The contrast agent was identified by analyzing cerebrospinal fluid by high-performance liquid chromatography and confirmed with probe mass spectrometric analysis.

Evaluation of iohexol clearance used to estimate glomerular filtration rate in clinically normal foals.

Objective: To determine whether pharmacokinetic analysis of data derived from a single i.v. dose of iohexol could be used to predict creatinine clearance and evaluate simplified methods for predicting serum clearance of iohexol with data derived from 2 or 3 blood samples in clinically normal foals.

Hematology, plasma biochemistry, and serosurvey for selected infectious agents in southern giant petrels from Patagonia, Argentina.

In conjunction with reproductive and feeding ecology studies on southern giant petrels (SGP, Macronectes giganteus) blood samples were collected for baseline health evaluations. Twenty-five adult SGP from a breeding colony in Chubut, Argentina, were sampled during two consecutive breeding seasons, 1999-2000 (n = 15) and 2000-01 (n = 10). Values for hematology, plasma biochemistry, and minerals are described for 20 birds in apparent good physical condition.

Thin layer chromatography convulsant screen extended by gas chromatography-mass spectrometry.

Acute onset convulsive disorders in the canine may result from exposure to a variety of toxicants including strychnine, insecticides, metaldehyde, zinc phosphide, methylxanthines, drugs of abuse, bromethalin, and the tremorgenic mycotoxins (roquefortine and penitrem A). Although several of the above can be identified in a single gas chromatography-mass spectrometry (GC-MS) screen most have to be determined by separate tests. This report describes a modification of the strychnine extraction procedure, which allows thin layer chromatographic (TLC) identification of strychnine, bromethalin, roquefortine, and penitrem A in suspect baits, stomach contents or vomitus, and extends the identification to a wide variety of drugs, pesticides, and environmental contaminants by GC-MS.

A case of anaemia in a neonatal warthog (Phacochoerus aethiopicus) and evaluation of serum-soluble iron in warthogs.

A 38-day-old male warthog (Phacochoerus aethiopicus) with marked anaemia (haematocrit = 14 %) presented to the Denver Zoological Gardens hospital with ataxia, tachypnoea, suspected stunted growth and cardiomegaly. The piglet demonstrated some features consistent with both iron deficiency anaemia and autoimmune haemolytic anaemia. Serum-soluble iron was below the level of detection (< 8.

Earliest cardiac toxicity induced by iron overload selectively inhibits electrical conduction.

Female guinea pigs were injected intraperitoneally with 0.083 g/kg iron dextran (Fe-D) to achieve progressively increasing levels of iron load; controls received dextran. Delayed and blocked cardiac conductivity at the Purkinje fiber-papillary muscle junction was initially observed with Fe-D loads of 0.

Mercury and selenium concentrations in livers and eggs of common loons (Gavia immer) from Minnesota.

Mercury and selenium act as mutual antagonists in mature birds, but their toxicity is additive or synergistic in avian embryos and immature birds. Twenty eggs and livers from 18 mature and 9 immature common loon carcasses found in Minnesota were collected. Livers and eggs were analyzed for mercury and selenium by atomic emission and atomic absorption spectroscopy.

A retrospective study on the disappearance of blood lead in cattle with accidental lead toxicosis.

Lead poisoning in cattle and other food animals is of public health significance because of the potential for human exposure to lead through ingestion of contaminated meat and milk products derived from lead-poisoned animals. In Michigan, lead poisoning in livestock is a reportable disease, and positive cattle are quarantined until they test negative (<0.05 ppm blood lead).

Relationship between plasma iohexol clearance and urinary exogenous creatinine clearance in dogs.

The objective of this study was to determine if plasma iohexol clearance, computed by a 1-compartment model defined by 3 plasma samples. was an accurate measure of glomerular filtration rate (GFR) in dogs. Twenty-two adult Beagle dogs of both genders were studied.

Intracellular magnesium concentrations in dogs with gastric dilatation-volvulus.

Objective: To quantify and compare intracellular magnesium concentrations (Mgi) in clinically normal dogs (control dogs) and dogs that have gastric dilatation-volvulus (GDV dogs) and to determine whether there is a difference in Mgi and serum magnesium concentrations (Mgs) between GDV dogs with and without cardiac arrhythmias.

Animals: 41 control dogs and 21 GDV dogs.

Procedure: Rectus abdominis muscle specimens were obtained from control and GDV dogs for determination of Mgi.

The use of blood analyses to evaluate mineral status in livestock.

Animal responses are useful means of evaluating and assessing nutritional status. Blood mineral concentrations can be useful nutritional responses, although there are important limitations. The nutritional value in monitoring blood mineral concentrations varies with the specific mineral, being generally most valuable for those minerals in which homeostasis is regulated primarily by renal excretion, as opposed to regulation by variable absorptive efficiency.

Augmentation of mercury-induced nephrotoxicity by endotoxin in the mouse.

Endotoxin (lipopolysaccharide; LPS) and mercury are compounds of food safety concern. Endotoxin is a product of cell walls of gram negative bacteria. Humans are constantly exposed to LPS through infection plus translocation into circulation from the gastrointestinal tract.

The postmortem diagnosis of cholecalciferol toxicosis: a novel approach and differentiation from ethylene glycol toxicosis.

The objectives of this study were to develop a novel approach to postmortem diagnosis of cholecalciferol (CCF) toxicosis in dogs using kidney, bile, and urine samples, and to differentiate CCF from ethylene glycol (EG) toxicosis. To achieve these objectives, specimens collected from 2 previous laboratory studies in which dogs were given a single oral toxic dose of CCF (8.0 mg/kg) were used.

Potentiation of mercury-induced nephrotoxicity by endotoxin in the Sprague-Dawley rat.

Endotoxin (lipopolysaccharide; LPS) and mercury are nephrotoxic compounds of food safety concern. Endotoxin is a product of cell walls of gram negative bacteria. Humans are constantly exposed to LPS through food, water and air.

Effects of methimazole on renal function in cats with hyperthyroidism.

The purpose of this study was to investigate the effects of methimazole on renal function in cats with hyperthyroidism. Twelve cats with naturally occurring hyperthyroidism and 10 clinically normal (i.e.

Gas chromatography/mass spectrometry identification and quantification of isazophos in a famphur pour-on and in bovine tissues after a toxic exposure.

A sample identified as "Warbex pour-on," expected to contain 13.2% famphur, and bovine tissue samples from 2 heifers that died after exhibiting signs of organophosphate intoxication were analyzed by gas chromatography/mass spectrometry (GC/MS). A product formulation problem was suspected because brain cholinesterase activities were depressed in both animals.

Use of pamidronate disodium to reduce cholecalciferol-induced toxicosis in dogs.

Objective: To determine whether pamidronate disodium can reduce cholecalciferol-induced toxicosis in a dose-related manner.

Animals: 20 clinically normal, 8- to 12-month-old male Beagles.

Procedure: All dogs were given 8 mg of cholecalciferol (CCF)/kg of body weight once orally, then were randomly assigned to 4 groups of 5 dogs each.

Use of pamidronate to reverse vitamin D3-induced toxicosis in dogs.

Objectives: To determine whether pamidronate disodium can reduce vitamin D3-induced hypercalcemia in dogs and whether combination treatment with calcitonin is more effective than treatment with pamidronate alone.

Animals: 20 clinically normal male Beagles.

Procedure: All dogs were given 8 mg of cholecalciferol (CCF)/kg of body weight once orally, then were assigned randomly to 4 groups of 5 dogs each.

Health evaluation of free-ranging rockhopper penguins (Eudyptes chrysocomes) in Argentina.

As part of annual colony counts in Santa Cruz Province, Argentina, a health survey of rockhopper penguins (Eudyptes chrysocomes) was conducted in 1994. Forty-five birds were examined during handling procedures, and blood and fecal samples were collected for laboratory analysis. All birds appeared to be in good condition.

Health evaluation of free-ranging guanaco (Lama guanicoe).

Twenty free-ranging guanaco (Lama guanicoe) in Chubut Province, Argentina, were immobilized for health evaluations. All but two animals appeared to be in good condition. Hematology, serum chemistry, and vitamin and mineral levels were measured, and feces were evaluated for parasites.