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Biomedical subjects

M E Mount

Publications and source records attributed to M E Mount.

At least 19 recordsLinked to original sources

Detection of equine antiplatelet and antineutrophil antibodies by enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) was standardised and applied for the detection of antiplatelet and antineutrophil antibodies using a heterologous system consisting of equine platelets or neutrophils and antisera raised in rabbits. The standardised technique consisted of using Immulon type 3 plate, 1 per cent gelatine as a blocking solution, poly-L-lysine buffer as a coating solution, unfixed antigen, 90 microliters test serum, horseradish peroxidase conjugated antibody and o-phenylenediamine dihydrochloride as a substrate. The number of unfixed platelets or neutrophils required for optimum detection of antibodies was 250,000 per well. Unfixed cellular antigens were as good as their extracts and superior to paraformaldehyde-fixed antigens in detecting specific antibodies. Microtitre plates coated with platelet or neutrophil antigens could be stored at 4 degrees and -70 degrees C for four to five weeks without significant loss of antigenicity. The ELISA was very sensitive in that antiplatelet antibody was detected up to a titre of 1:204,800 and antineutrophil antibody to a titre of 1:51,200. Some cross-reactivity (1:1600) was detected in antiplatelet and antineutrophil sera for neutrophil and platelet antigens, respectively. Platelet-associated antibody was also detected in extracts from platelets pretreated with 1:2 and 1:8 dilutions of antiplatelet serum. Standardised ELISA detected antiplatelet antibodies in nine and antineutrophil antibodies in three of 100 isologous equine blood typing sera.

Animals

Clinical illness associated with a commercial tick and flea product in dogs and cats.

A commercial flea and tick product containing 9.0% fenvalerate for use in dogs and cats was suspected of causing illness. An acute toxicity study was performed in 10 dogs and 10 cats exposed to the product orally (po) and dermally at differing doses. Samples were obtained for DEET and fenvalerate analysis. Oral dosing of dogs and cats produced severe clinical illness at doses as low as 0.66% of a can (7 ounce spray can)/kg body weight. Dermal application of the product resulted in minor clinical abnormalities in dogs. Oral exposure at 0.5% can/kg body weight resulted in severe illness, and dermal application caused severe illness or death in cats at 20% and 40% of a can/kg body weight. The cats receiving 10% of a can/kg body weight dermally became depressed for several hours but recovered uneventfully. Serum DEET concentrations closely paralleled the clinical signs observed in the animals. Serum concentrations of DEET above 20 ppm were considered diagnostic for intoxication. Urine concentrations of DEET above 1 ppm and tissue (liver, bile, and kidney) concentrations of DEET above 10 ppm were supportive of poisoning; values near 100 ppm were diagnostic for fatal poisoning.

Administration, Oral

Surreptitious ingestion of a long-acting vitamin K antagonist/rodenticide, brodifacoum: clinical and metabolic studies of three cases.

The vitamin K metabolism of three patients with factitious purpura due to brodifacoum ingestion was studied. These patients, who presented with bleeding disorders due to deficiency of the vitamin K-dependent blood clotting proteins, were refractory to vitamin K1 at standard doses and required fresh frozen plasma to control bleeding until large doses of vitamin K1 were used. Metabolic studies demonstrated a blockade in vitamin K utilization, consistent with the presence of a vitamin K antagonist, but the patients denied use of anticoagulants. Warfarin assays were negative. We show that the factitious purpura in each patient was due to the surreptitious ingestion of brodifacoum, a potent second generation long-acting vitamin K antagonist used as a rodenticide. The coagulopathies responded to long-term therapy with large doses of vitamin K1. The serum elimination half-time for brodifacoum ranged from 16 to 36 days in these patients. The anticoagulant effect is of long duration, requiring chronic vitamin K treatment. With increasing availability of new rodenticides, factitious purpura due to surreptitious ingestion of these potent vitamin K antagonists is emerging as a new problem, previously associated with warfarin, with important implications for diagnosis and treatment.

4-Hydroxycoumarins

Diagnostic importance of vitamin K1 and its epoxide measured in serum of dogs exposed to an anticoagulant rodenticide.

Administration of vitamin K1, SC, to anticoagulant-poisoned (diphenadione) dogs provided diagnostic information within 4 hours, when vitamin K1 and its epoxide were measured in canine sera. Twelve dogs (2 groups of 6) were given 2.5 mg of diphenadione/kg of body weight for 3 days. Dogs were treated with vitamin K1, 2.5 (n = 6) or 5 mg/kg/day (n = 6) SC for 21 days, and their responses were compared. Four nonexposed control dogs were given 5 mg of vitamin K1/kg/day. Serum concentration of vitamin K epoxide was significantly (P less than 0.02) higher in diphenadione-exposed dogs than in control dogs 1 to 4 hours after the initial vitamin K1 treatment on day 4. Vitamin K epoxide/vitamin K1 ratios were similarly higher and became more distinct. Cessation of vitamin K1 therapy on day 24 resulted in prolongation of one-stage prothrombin times in diphenadione-exposed dogs, becoming clearly evident on day 27. Serum vitamin K1 concentrations were not detectable on day 27 in diphenadione-exposed dogs, whereas serum vitamin K1 concentrations were readily detectable in control dogs. One-stage prothrombin time changes, during days 24 to 32, indicated 5 mg of vitamin K1/kg provided better protection than did 2.5 mg of vitamin K1/kg. Coagulopathy in the dogs was resolved by day 32.

Animals

Diagnosis and therapy of anticoagulant rodenticide intoxications.

The mechanism of toxicity and agents of anticoagulant rodenticides are discussed. The diagnosis of anticoagulant poisoning is outlined and discussed by applying clinical, laboratory, and therapeutic response measures as a means to confirm poisoning. Additional therapeutic concerns and newly developed diagnostic tests are discussed. Application of the therapeutic and diagnostic measures provides a successful plan to manage anticoagulant poisonings.

Animals

Production of antibodies and development of an immunoassay for the anticoagulant, diphacinone.

Diphacinone, a commonly used anticoagulant rodenticide, was coupled to protein via an (O-carboxymethyl) oxime bridge. Immunization in rabbits produced antibodies with good ability to recognize the hapten as demonstrated by indirect EIA and affinity column adsorption. A competitive EIA was developed which clearly measured 10 micrograms/L diphacinone concentrations showing the sensitivity of the assay. Cross-reactivity study with chlorophacinone showed that the antisera possessed a high degree of diphacinone specificity.

Animals

Polypeptide fluoroacetate derivatives. Synthesis and 19F n.m.r.

The synthesis and characterization of monofluoroacetyl (MFAc) functionalized haptens are described. These were covalently bound to polypeptide carriers (bovine serum albumin and poly-D-lysine) by primary amine/succinimide ester or primary amine/acid chloride coupling. Epitopic densities of the resulting antigens were determined by both 19F n.m.r. and picryl sulfonic acid assays. 19F n.m.r. experiments defining the stability of MFAc ester and amide linkages as a function of media (including in vitro), time, and temperature are presented. These results indicate that MFAc functionalized antigens are well suited for further immunologic studies.

Fluorine

Comparison of measurement of dialkyl phosphates in milk/urine and blood cholinesterase and insecticide concentrations in goats exposed to the organophosphate insecticide, imidan.

Recognition of exposure to imidan was assessed in goats by dialkyl phosphate concentrations, blood cholinesterase (ChE) determinations, and blood imidan concentrations. Groups of three goats received 5.0 mg imidan/kg/day (low dose) or 10 mg imidan/kg/day (high dose) for 7 days orally. One goat received no imidan and one goat received an acute single dose (200 mg/kg). The urine of all treated goats was examined for the excretory dialkyl phosphates, O,O-dimethyl phosphorodithioate (DMDTP) and O,O-dimethyl phosphorothionate (DMTP). The overall mean DMDTP urinary concentration was 19.1 ppm (10-mg/kg treatment group) and 7.2 ppm (5-mg/kg treatment group). These metabolites rapidly disappeared following removal of the treatment except in those goats clinically affected. Milk contained no identifiable concentrations of dialkyl phosphates. Cholinesterase depression was observed in all imidan-treated goats, and a dose effect was observed. No imidan was detected in whole blood of either the 5- or 10-mg/kg treatment groups. Low blood concentrations (ppb) of imidan were measured in the acute single-dose exposed goat. Both urinary DMDTP and blood ChE provided recognition of imidan exposure. DMDTP, however, was immediately present in urine after exposure and provided stronger support for organophosphate exposure than did blood ChE.

Animals

Practical toxicologic diagnosis.

Strychnine toxicosis is characterized by inducible tetanic seizures and metaldehyde poisoning by fine fasciculations progressing to generalized tremors and seizures. Intoxication with 1080 causes seizures, random running movements, vomiting, defecation, urination, acidosis and hyperglycemia. Intoxication with rodenticides causing coagulopathy is characterized by hemorrhage into body cavities but not necessarily external hemorrhage. Anticholinesterase insecticides cause salivation, urination and defecation, while chlorinated hydrocarbon insecticides cause CNS disturbances. Ethylene glycol intoxication results in ataxia, depression, coma, vomiting and tachypnea, followed by acute renal failure. Urea poisoning causes bloat and CNS signs in cattle. Monensin intoxication in horses lasts several days and causes stiffness, colic, uneasiness and recumbency. Salt poisoning results in depression, seizures and hypernatremia. Lead poisoning is associated with central and peripheral nervous system signs, as well as increased numbers of nucleated RBC and basophilic stippling of RBC. Arsenic poisoning results in GI pain, diarrhea, weakness and death. Copper toxicosis in sheep is manifested by hemolytic anemia, hemoglobinemia and hemoglobinuria. Plants that may intoxicate domestic animals include sorghum, greasewood, halogeton, water hemlock, Japanese yew, larkspur, lupine, milk-weed, philodendron, oleander, castor bean and precatory bean.

Animals

Diagnostic value of urinary dialkyl phosphate measurement in goats exposed to diazinon.

Recognition of exposure to diazinon, an organophosphate insecticide, was studied in goats. Urine and milk dialkyl phosphate concentrations (DETP; O,O-diethyl phosphorothionate) and blood cholinesterase activity (ChE) and diazinon concentrations were measured. Groups (n = 3 each) given (orally) diazinon at doses of 0.5 mg/kg for 7 days (small dose) or 5 mg/kg for 7 days (large dose) were compared with goats acutely exposed to single doses of 150 mg/kg (n = 1) or 700 mg/kg (n = 1). Clinical signs of intoxication occurred only in the goat given the 700 mg/kg dose. Urinary DETP concentrations were sensitive indicators of diazinon exposure and provided quantitative differences between small, large, and acute dosage exposures. Milk DETP concentrations were not detected. Cholinesterase measurement was useful only in the acute exposure studies. Whole blood diazinon concentrations were detected only in goats given the large dose for 7 days and acutely exposed. Measurement of urinary DETP was a sensitive aid for recognition of diazinon exposure.

Animals

Fatal acorn poisoning in a horse: pathologic findings and diagnostic considerations.

Acorn poisoning was diagnosed in an 11-year-old Quarter Horse with signs of severe colic, tachycardia, hyperpnea, abdominal borborygmus, rectal tenesmus, and hemorrhagic diarrhea. The diagnosis was based on history and predisposing factors, clinical signs, laboratory data, acorn husks in the feces, the urinary gallic acid equivalent concentration, and necropsy findings. The most striking pathologic changes were gastrointestinal and mesenteric edema, ulcerative enterocolitis, and nephrosis.

Animals

Mechanism of diphacinone rodenticide toxicosis in the dog and its therapeutic implications.

Vitamin K1 (5 mg/kg of body weight/day divided for several 5-day regimens) was effective in preventing bleeding diathesis in diphacinone-poisoned dogs. Diphacinone, a vitamin K-inhibiting rodenticide, was given 2.5 mg of diphacinone/kg of body weight orally in divided doses 2 times daily for 3 days. One dog was given 5.0 mg of warfarin/kg in 2 divided doses for 3 days. Hemograms and biochemical profiles were performed every other day. A pancreatic exocrine function test was performed before and after administration of diphacinone and warfarin. All dogs were monitored, using routine coagulation screening tests and assays of coagulation factors II, VII, IX, and X. When laboratory results or clinical illness indicated hemorrhage, diphacinone-treated dogs were given 5.0 or 2.5 mg of vitamin K1/kg in divided doses 3 times a day for 5 days. The warfarin-treated dog was given 2.5 mg of vitamin K1/kg of body weight in divided doses 3 times a day for 5 days. Of the diphacinone-treated dogs, 1 dog (given 2.5 mg of vitamin K1/kg) required 3 vitamin K regimens and 2 dogs (given 5.0 mg of vitamin K1/kg) required only 2 vitamin K regimens. The warfarin-treated dog required only 1 vitamin K1 regimen. Bleeding was observed in the diphacinone-treated dogs up to 2 weeks after treatment. The vitamin K-enzyme complex was inhibited in diphacinone-treated dogs for approximately 30 days, as indicated by routine coagulation screening tests and coagulation factor inhibition. Hepatic dysfunction was not observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Diagnostic criteria for carbaryl poisoning in sheep.

Sheep were used to study the effect of carbaryl in liver, heart, and brain and on cholinesterase activity. Carbaryl residues greater than or equal to 0.01 ppm in the brain were present in all sheep dying after dosing. Sheep dying acutely had higher levels of carbaryl and greater than or equal to 50% inhibition of brain cholinesterase activity, while sheep with prolonged death had lower carbaryl levels and less cholinesterase inhibition. Prolonged deaths were associated with pulmonary embarrassment, enteritis, hyperthermia, and metabolic acidosis. Carbaryl was rapidly degraded in stored blood samples but was stable in dead brain tissue.

Animals