Gas-Liquid Chromatographic Determination of T-2 Toxin in Plasma

The gas-liquid chromatographic method for the determination of T-2 toxin in plasma is described. The toxin is extracted with benzene, washed with aqueous sodium hydroxide, and chromatographed on a small Florisil column; the heptafluorobutyryl derivative is prepared by reaction with heptafluorobutyrylimidazole. The T-2 HFB derivative is chromatographed onOV-1 at 230°C and measured with an electron capture detector. Iso-T-2, an isomer of T-2 toxin, is added to samples as an internal standard before extraction. Recoveries averaged 98.0 ± 5.5% at levels ranging from 50 to 1000 ng/m L. The limit of detection is 25 ng/mL.

Comparative pathologic changes in broiler chicks on feed amendedwith Fusarium proliferatum culture material or purified fumonisinB1 and moniliformin*

Feed amended with autoclaved culture material (CM) of Fusarium proliferatum containing fumonisin B1 (FB1) (61-546 ppm), fumonisin B2 (FB2) (14-98 ppm) and moniliformin (66-367 ppm) was given to 228 male chicks in three separate feeding trials. In a fourth feeding trial, purified FB1 (125 and 274 ppm) and moniliformin (27 and 154 ppm) were given separately and in combination (137 and 77 ppm, respectively). Chicks that died during the trial periods, survivors and controls were subjected to postmortem examination. Specimens (liver, kidney, pancreas, lung, brain, intestine, testis, bursa of Fabricius, heart and skeletal muscle) were examined grossly and preserved for subsequent histopathologic and ultrastructural examination. Prominent gross lesions in affected birds fed diets amended with CM or purified FB1 and moniliformin included ascites, hydropericardium, hepatopathy, nephropathy, cardiomyopathy, pneumonitis, gizzard ulceration, and enlarged bursa of Fabricius filled with caseous material. The various concentrations of FB1 and moniliformin in the amended rations produced well-defined dose-response lesions in all groups in all four trials. Histopathologic changes included hemorrhage, leucocytic infiltration, fatty change or infiltration, individual cell necrosis and fibrosis in liver, kidneys, lungs, heart, intestines, gizzard, bursa of Fabricius and pancreas. Edema and hemorrhage were prominent in brains of treated birds. Ultrastructural changes included cytoplasmic and nuclear enlargement of cells in affected liver, lungs, kidneys, heart and pancreas. There were thickened membranes of the smooth endoplasmic reticulum, dilation of the rough endoplasmic reticulum with loss of ribosomes and vacuolated or deformed mitochondria.

Weakness, tremors, and depression associated with macadamia nuts in dogs

The ASPCA National Animal Poison Center managed 29 cases of ingestion of commercially available macadamia nuts in dogs during a 5-y period. Clinical signs included, from most to least, weakness, depression, vomiting, ataxia, tremor, hyperthermia, abdominal pain, lameness, stiffness, recumbency, and pale mucous membranes. The onset of clinical signs was reported as < 12 h in 79% of the cases. The duration of clinical signs for the majority of cases was < 24 h. The amount of macadamia nuts ingested was estimated in 72% of the calls with a mean of 11.7 g/kg bw. In an attempt to reproduce the syndrome, 4 dogs were gavaged with 20 g macadamia nuts/kg bw in a water slurry. The experimentally dosed dogs developed weakness, manifested by the inability to rise 12 h after dosing, mild central nervous system depression, vomiting, and hyperthermia, with rectal temperatures up to 40.5 C. Mild elevations in serum triglycerides and serum alkaline phosphatase were detected. Lipase values peaked sharply at 24 h and returned to normal by 48 h after dosing. Other serum biochemical and electrolyte determinations were unremarkable. Serum lipoprotein electrophoresis determinations were unchanged from baseline. The mechanism of the syndrome is unknown. All field and experimental dogs recovered uneventfully within 1 to 2 d whether treated by a veterinarian or not.

Ibuprofen, aspirin and acetaminophen toxicosis and treatment in dogs and cats

Toxicosis to 3 commonly available analgesics--ibuprofen, aspirin and acetaminophen--occurs in dogs and cats after acute ingestion or repetitive administration of therapeutic or excessive doses. Whereas in acute exposure, where the clinical course of an overdose to all 3 drugs is predictable in relation to the amount ingested, in chronic exposure to therapeutic doses of aspirin and ibuprofen, the development of gastric ulcers and analgesic nephropathy is unpredictable. Ibuprofen is not recommended for prolonged treatment in dogs and cats due to the likelihood of ulcer formation. Although gastric mucosal adaptation usually occurs with repeated therapeutic doses of aspirin, some individuals nevertheless develop gastric ulcers; simultaneous administration of the prostaglandin analogue misoprostol can reduce the risk. Following acute ingestion of aspirin or ibuprofen, treatment is essentially symptomatic and supportive following early decontamination procedures. Gastrointestinal protectants and i.v. fluids with sodium bicarbonate are generally recommended. Acetaminophen toxicosis is usually associated with single acute ingestion, and the primary target organs affected are the liver and the red blood cells in dogs and cats respectively. Because signs can progress rapidly with acute acetaminophen overdose, administration of N-acetylcysteine is always recommended, even when the history is unclear. This report summarizes the common clinical presentations of dogs and cats exposed to therapeutic or excessive doses of ibuprofen, aspirin or acetaminophen, and describes the treatment procedures advised by the ASPCA-National Animal Poison Control Center.

Malignant hyperthermia-like reaction secondary to ingestion of hops in five dogs

Five dogs, 4 of which were Greyhounds, suffered adverse effects secondary to the ingestion of spent hops. Mean time to onset of clinical signs was 3 hours, and clinical signs included marked hyperthermia, restlessness, panting, vomiting, signs of abdominal pain, and seizures. Four of the 5 dogs died despite aggressive therapeutic measures, and there was rapid onset of rigor mortis in 3. The overrepresentation of Greyhounds, coupled with the clinical signs, was suggestive of a malignant hyperthermia-like response to the ingestion of hops. It also is possible that hops contain an uncoupler of oxidative phosphorylation.

Can household pets be used as reliable monitors of lead exposure to humans?

We investigated the validity of dogs and cats as sentinels of environmental lead exposure to humans. This paper reports findings from a study conducted in Granite City, IL, during the summer of 1991. At this site, a former secondary lead smelter had been in activity for more than 80 years. The smelter was shut down in 1982. The surrounding area was found to be contaminated with lead, with soil lead concentrations above 5000 ppm in some places. The Illinois Department of Public Health conducted a survey in the community to determine the effects of lead on the local population. We sampled dogs and cats owned by these people. Our results suggest that living near a closed lead smelter, with heavy soil contamination, was not associated with high blood lead concentrations in pets, or their owners. There was a significant relationship between BLC (blood lead concentrations), in indoor pets and younger children, which was consistent with our hypothesis that pets could be used to monitor childhood lead exposure. We also found that, when there was one pet with a high BLC in a house, the likelihood of finding one person with a BLC above 10 micrograms/dl was significantly increased.

Serohematologic alterations in broiler chicks on feed amended with Fusarium proliferatum culture material on fumonisin B1 and moniliformin

Two hundred twenty-eight male broiler chicks (Columbia x New Hampshire) were given feed amended with autoclaved culture material of Fusarium proliferatum containing fumonisin B1 (FB1) at 61, 193, and 546 ppm, fumonisin B2 (FB2) at 14, 38, and 98 ppm, and moniliformin at 66, 193, and 367 ppm in 3 separate feeding trials (amounts of toxin in each trial, respectively). Birds were started on amended rations at days 1, 7, and 21 and continuing for 14 days. Of serum chemistry parameters, only glucose was significantly decreased. Significant increases were noted in serum cholesterol, sodium, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and gamma-glutamyl transferase. Of the hematologic parameters, significant decreases were noted in red blood cell counts, hemoglobin, packed cell volume, and white blood cell counts. Immunologic changes included impaired anti-Newcastle disease antibody hemagglutination inhibition titers associated with relative decreases in total serum globulins and increases in albumin/globulin ratios. The changes were noted in all treatment groups when compared to controls.

Treatment of acute isoniazid overdose in dogs

The National Animal Poison Control Center received 28 calls of isoniazid (INH) exposures in dogs and cats between 1987 and 1993. The ingestion of a single 300 mg INH tablet was the most common complaint. Isoniazid has a low therapeutic margin and produces life threatening signs in dogs ingesting single 300 mg human tablets. The LD50 of INH in dogs is estimated at 50 mg/kg bw, which is probably similar to that for humans. However, rodents are among the species most resistant to INH and thus are not good animal models for toxic dose extrapolation. The more consistent clinical signs reported were recurrent clonic-tonic seizures followed by a stuporous state with poor response to stimulus. Ideal treatment combines vitamin B6 given as a single i.v. bolus at an equivalent dose to the amount of INH ingested and anticonvulsants such as 1 mg diazepam/kg bw. This combination acts synergistically to improve GABAergic transmission in the CNS and has proved effective in protecting animals from further convulsions and death, even after several seizure episodes, as often encountered in clinical situations.

Relationship between soil lead, dust lead, and blood lead concentrations in pets and their owners: evaluation of soil lead threshold values

This paper reports the results of a study conducted in Granite City, Illinois during the months of August through October 1991. The study involved a subpopulation of 77 households having 106 dogs and cats which was a corollary to a major study conducted in humans by the Illinois Department of Public Health to evaluate lead exposure. A secondary lead smelter had been in operation in this town for almost 80 years and was shut down in 1982. Important soil contamination with lead was reported and this paper presents data regarding levels of soil and dust lead and associated blood lead concentrations in animals and their owners in a total of 77 households. Overall, blood lead concentrations (BLC) were low (0-13 micrograms/dl in the animal owners; 0-28 micrograms/dl in pets). There was no significant relationship between soil or dust lead and BLC in humans; however, the relationship was significant in animals. Odds ratios were computed to determine whether 500 or 1000 ppm lead in environmental samples was associated with increased risk of having a high BLC. We could not find any increased risk in humans, while the risk did increase in animals. It is concluded that animals are more at risk than their owners of having a high BLC when exposed to the same contaminated environment and can be used to monitor the bioavailability of lead.

Toxicity of melaleuca oil and related essential oils applied topically on dogs and cats

Cases of melaleuca oil toxicosis have been reported by veterinarians to the National Animal Poison Control Center when the oil was applied dermally to dogs and cats. In most cases, the oil was used to treat dermatologic conditions at inappropriate high doses. The typical signs observed were depression, weakness, incoordination and muscle tremors. The active ingredients of commercial melaleuca oil are predominantly cyclic terpenes. Treatment of clinical signs and supportive care has been sufficient to achieve recovery without sequelae within 2-3 d.

Low blood lead concentration associated with various biomarkers in household pets

A former secondary lead smelter was in operation in Granite City, Ill, until the early 1980s. As a result, the surrounding area is heavily contaminated with lead. Soil concentrations as high as 5,000 ppm have been measured in prior studies. Because of growing concerns about health defects associated with low levels of lead exposure in human beings, a major study has been conducted on people living in the area. The study reported here was a corollary to the human exposure study. Lead concentration was determined in 84 dogs and 26 cats in the town and ranged between < 5 and 28 micrograms/dl. None of the dogs had clinical signs of lead poisoning. The CBC and serum biochemical values did not indicate many significant differences between dogs with a high (> or = 10 micrograms/dl) or low blood lead concentration (BLC). Hemoglobin concentrations were lower, and WBC counts were higher in dogs and cats with higher BLC, but they were still within reference ranges. Free erythrocyte protoporphyrin concentration was determined. Normal values appeared to be similar for dogs and cats. Only animals with BLC > or = 20 micrograms/dl were found to have somewhat increased concentration of free erythrocyte protoporphyrin. delta-Aminolevulinic acid dehydratase activity was measured and found to be negatively correlated with BLC. The relation was strong, even at low BLC (5 to 10 micrograms/dl) in both species. Age or sex difference was not observed. Therefore, biological changes associated with low BLC were limited to BLC in the 10- to 30-micrograms/dl range.

Lymphocyte cytotoxicity and erythrocytic abnormalities induced in broiler chicks by fumonisins B1 and B2 and moniliformin from Fusarium proliferatum

Peripheral blood lymphocytes were isolated from broiler chicks that had ingested feed amended with autoclaved Fusarium proliferatum culture material containing fumonisin B1 (FB1), fumonisin B2 (FB2) and moniliformin. Lymphocyte viability was determined for birds that were placed on amended rations at day 1 or day 7 of age at three different levels of mycotoxins, ranging from 61-546 ppm FB1, 14-94 ppm FB2 and 66-367 ppm moniliformin. Reduction of the tetrazolium salt, MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide], to yield MTT formazan, based on mitochondrial metabolic activity, was used to assess cell viability. Lymphocyte cytotoxic effects were observed in all treatment groups on day 21; chicks that started on amended feed at day 1 of age were affected more than those that started at day 7. Abnormal erythrocytes resembling early stages of erythroblasts were observed in peripheral blood from test chicks. Abnormally shaped red cells (poikilocytes) having a spindle-shape with one or both ends pointed were present. Some red cells appeared to be undergoing mitosis. Both reduced lymphocyte viability and abnormal erythrogenesis occurred in chicks given feed amended with F. proliferatum culture material containing FB1, FB2 and moniliformin.

Mortality in broiler chicks on feed amended with Fusarium proliferatum culture material or with purified fumonisin B1 and moniliformin

Two hundred twenty-eight male chicks (Columbia x New Hampshire) were given feed amended with autoclaved culture material (CM) of Fusarium proliferatum Containing fumonisin B1 (FB1), fumonisin B2 (FB2) and moniliformin in 3 separate feeding trials. Purified FB1 and moniliformin were given separately and in combination in a fourth feeding trial. Birds were given amended rations at day 1 (Trial 1 and 4), day 7 (Trial 2), and day 21 (Trial 3) and their respective ration was given for 28 days (Trial 1), 21 days (Trial 2), 7 days (Trial 3), and 14 days (Trial 4). FB1 concentrations were 546, 193, and 61 ppm; FB2 were 98, 38 and 14 ppm; and moniliformin were 367, 193, and 66 ppm in the first 3 feeding trial regimens. Chicks in Trial 4 were given dietary concentrations of purified FB1 at 274 and 125 ppm, and moniliformin at 154 and 27 ppm. FB1 and moniliformin, both alone and in combination, produced dose-responsive clinical signs, reduced weight gains and mortality in chicks. Age of birds given amended feeds had little difference in the clinical response; however, those given the rations from days 7 or 21 were slightly less susceptible than those given rations beginning at 1 day of age. Additive effects were noted when the toxins were given in combination. When toxins were given separately, adverse effects took longer to occur. A system to monitor pattern and rate of defecation (RD) was developed for assessing the chicks' approach to feed, water and heat source as illness progressed. Our results indicate that chicks fed corn heavily infected with F. proliferatum under field conditions could suffer acute death similar to that described for 'spiking mortality syndrome' during the first 3 weeks of age.

Embryopathic and embryocidal effects of purified fumonisin B1 or Fusarium proliferatum culture material extract on chicken embryos

One hundred eight fertile eggs (Columbia x New Hampshire) were assigned to 10 groups of 10 eggs each (2 control groups had 14 eggs each). Five groups of eggs were inoculated on day 1 of incubation, while the other 5 groups were inoculated on day 10. The inoculum of the 4 treatment groups on both day 1 and 10 consisted of 1,10, or 100 microM purified fumonisin B1 (FB1) or a culture material extract (CME) of Fusarium proliferatum, having known amounts of FB1, FB2 and moniliformin (FB1 20 microM; FB2 4 microM and moniliformin 7 microM). Inoculum consisted of the respective toxin(s) dissolved in 100 microliters double distilled, autoclaved water (diluent). Control eggs were inoculated with diluent only. Mortality was both dose- and time-responsive in all treatments. Eggs inoculated on day 1 with 1 microM FB1 had 50% mortality; 10 microM FB1 had 70% mortality; 100 microM FB1 had 100% mortality; and CME had 100% mortality. Eggs inoculated on day 10 with 1,10 or 100 microM FB1 or CME had 30, 60, 90 and 80% mortality, respectively. Normal chicks were hatched from all control eggs. The median death times (MDT50) were inversely dose-responsive in all treatments, ranging from 3.0 to 7.4 days in embryos exposed on day 1 and from 3.2 to 9.0 days in those exposed on day 10. Early embryonic changes in exposed embryos included hydrocephalus, enlarged beaks and elongated necks. Pathologic changes were noted in liver, kidneys, heart, lungs, musculoskeletal system, intestines, testes and brain toxin-exposed embryos.

Biliary excretion and enterohepatic cycling of zearalenone in immature pigs

The disposition of the estrogenic mycotoxin, zearalenone (ZEN) in female, 10- to 14-week-old Yorkshire pigs was investigated. Pigs were administered [3H]ZEN intravenously (IV; n = 4; 5 mg/kg; 15 microCi/kg), orally (n = 4; 10 mg/kg; 30 microCi/kg), or intravenously with bile removal (IVB; n = 2; 5 mg/kg; 15 microCi/kg). Plasma, urine, feces, and bile (IVB pigs only) were serially collected and analyzed for radioactivity. Metabolite profiles were determined in plasma and bile by HPLC. The biological half-life of total plasma radioactivity in IV and orally dosed pigs (86.6 hr) was much larger than that of IVB animals (3.34 hr). Metabolite profiles of plasma concentration vs time demonstrated secondary peaks in concentration during the terminal elimination phase in IV and orally dosed pigs. In IVB pigs these peaks were absent, relative metabolite profiles were altered, and ZEN and metabolites were no longer detectable after 16 hr post-dosing. Biliary recovery of radioactivity, principally as glucuronide conjugates, was extensive (45.61 +/- 4.7%) in IVB pigs and significantly greater (p < 0.05) than that of fecal recovery of radioactivity in IV (6.56 +/- 0.78) or orally dosed (21.74 +/- 1.56%) pigs. Intraduodenal administration of bile containing [3H]ZEN and metabolites resulted in recovery of 64.56 +/- 4.89% of the dose in bile, 20.78 +/- 3.94% in urine, and the presence of glucuronide conjugates of ZEN and alpha-zearalenol (ZEL) in portal and jugular plasma. Differences in metabolite profiles between administered bile and sampled plasma suggest that the intestinal mucosa was active in reducing ZEN to ZEL and conjugating these metabolites with glucuronic acid. These studies provide evidence for extensive biliary secretion and enterohepatic cycling of ZEN and metabolites in pigs.

Neuropathologic findings of bromethalin toxicosis in the cat

Ten random source male domestic shorthair cats, 2 to 6 years old and 3.0-4.4 kg body weight, were each given a single oral dose (1.5 mg/kg) of bromethalin (cat Nos. 1-5) or bait vehicle carrier (cat Nos. 6-10). Bromethalin-dosed cats developed a toxic syndrome characterized by ataxia, focal motor seizures, vocalization, decerebrate posture, decreased conscious proprioception, recumbency, depression, and semicoma. Bromethalin-dosed cats were euthanatized if seizure activity or hindlimb paralysis developed. Survival times were 48 hours (cat No. 1), 89 hours (cat No. 2), 90 hours (cat No. 3), and 97 hours (cat No. 4). Control cats (cat Nos. 6-10) and one bromethalin-dosed cat (cat No. 5) were euthanatized on day 20 after dosing. Spongy change (edema--characterized by the formation of vacuoles in extracellular spaces and myelin lamellae), hypertrophied fibrous astrocytes, and hypertrophied oligodendrocytes were observed in the white matter of the cerebrum, cerebellum, brain stem, spinal cord, and optic nerve of all bromethalin-dosed cats. Spongy change occasionally extended into contiguous cerebellar Purkinje cell layer and cerebral cortical gray matter. The severity of lesions varied among cats but was most pronounced in cat No. 5 (480 hours after dosing). A leukocytic inflammatory response, gitter cell (macrophage) response, or axonal degeneration was not observed in the vacuolated areas. Ultrastructural findings included separation of myelin lamellae at the interperiod lines with the formation of intramyelinic vacuoles (intramyelinic edema), rupture and coalescence of intramyelinic vacuoles into larger extracellular spaces (spongy change), and pronounced cytosolic edema of astrocytes and oligodendroglial cells.

Case reports of lead poisoning in dogs from the National Animal Poison Control Center and the Centre National D'Informations Toxicologiques, Veterinaires: anecdotes or reality?

This paper presents case reports of lead toxicoses from 2 major animal poison control centers in Europe and North America, gathered from 1985 through 1989. All results examined here involved cases assessed as "toxicosis" or "suspected toxicosis" by the National Animal Poison Control Center (NAPCC) or the Centre National d'Informations Toxicologiques Veterinaries (CNITV). 537 cases were reported to the NAPCC, most of them concerning dogs (59%). In France, most of the 362 cases involved cattle (57.2%). There was an increased number of cases reported during late summer and early fall, and a decreased number of cases in November and December, in both centers. Dogs intoxicated were predominantly young animals (60% were less than 2 years old). No sex difference was noted. Pure bred dogs appeared more often involved than mixed-breed ones, but the breed distribution closely resembles dog breed distribution in the US. The source of lead was usually unknown and, when information was available, paint seemed to be the most common cause of poisoning. Clinical signs reported to the animal poison control centers involved the CNS and GI tract. Results from the French and the American database showed similar trends. They are compared to data from veterinary clinics and veterinary colleges in the US and Australia. In each case, data are very similar to what was reported to the CNITV and the NAPCC. It is concluded that animal poison control centers databases can provide a useful tool for better knowledge of animal poisoning. They can also help identify unexpected toxicologic problems related to drug administration or pesticide use.

Effects of an extract of Gingko biloba on bromethalin-induced cerebral lipid peroxidation and edema in rats

The effects of administration of a commercially available extract of Gingko biloba (EGB) on bromethalin-induced brain lipid peroxidation and cerebral edema in adult male Sprague-Dawley rats was determined. Gingko biloba extract was given (100 mg/kg) by gavage immediately after bromethalin (1.0 mg/kg) administration. Rats were euthanatized at 24 hours after dosing. Brain lipid peroxidation was determined by measurement of brain malonaldehyde-thiobarbituric acid chromophore (MDA-TBA) concentration, brain sodium concentration, and brain water content. Treatment of bromethalin-dosed rats (10/group) with EGB was associated with a statistically significant (P less than 0.05) decrease in clinical sign severity, compared with bromethalin-dosed saline solution-treated rats. All rats given bromethalin and saline solution developed clinical signs of toxicosis including CNS depression, hind limb weakness, ataxia, paralysis, and coma. Some rats given bromethalin and EGB developed clinical signs, however, none developed hind limb paralysis. The brain MDA-TBA concentration (2.4 +/- 0.5 delta MDA-TBA concentration/mg of protein), percentage of water in brain tissue (80.3 +/- 0.30%), and brain sodium concentration (6.68 +/- 0.21 mg/g of dry weight) were significantly increased in rats given bromethalin and saline solution, compared with control rats given saline solution (1.0 +/- 0.1 delta MDA-TBA concentration/mg of protein; 78.1 +/- 0.33% water in brain tissue; 4.83 +/- 0.30 mg of brain Na+/g of dry weight) and rats given bromethalin and EGB (1.6 +/- 0.2 delta MDA-TBA concentration/mg of protein; 79.3 +/- 0.31% water in brain tissue; 5.37 +/- 0.34 mg of brain Na+/g of dry weight).(ABSTRACT TRUNCATED AT 250 WORDS)

Electroencephalographic changes associated with bromethalin toxicosis in the dog

Electroencephalogram (EEG) recordings were obtained before and during the clinical syndrome induced by a bromethalin rodenticide given to dogs. Nine dogs given 6.25 mg bromethalin/kg po developed clinical signs and EEG abnormalities 15 to 58 h postdosing. Predominant abnormal EEG changes included spike and spike-and-wave EEG patterns (66%), high voltage slow wave (HVSA, 50-150 microV, 1-6 Hz) activity (44%) photoconvulsive or photoparoxysmal irritative responses (44%), and marked voltage depression (dominant activity less than 10 microV) in all leads (33%).

Diagnosis of bromethalin toxicosis in the dog

Dogs given a single oral dose of bromethalin at 6.25 mg/kg developed a toxic syndrome characterized by hyperexcitability, tremors, seizures, depression, and death within 15-63 hours after bromethalin administration. Gross lesions included mild cerebral edema (2/5) and mild pulmonary congestion (2/5). Histologic lesions included diffuse white matter spongiosis (5/5), mild microgliosis (3/5), optic nerve vacuolization (3/5), mild thickening of Bowman's capsule (2/5), and occasional splenic megakaryocytes (2/5). Ultramicroscopic examination of midbrain stem revealed occasional swollen axons, intramyelinic vacuolization, and myelin splitting at the intraperiod line. Bromethalin was detected in kidney, liver, fat, and brain tissues, using gas chromatography with electron capture detection. Photodegradation of extracted bromethalin may limit accurate quantification of tissue residues.

Prevention of T-2 toxin-induced morphologic effects in the rat by highly activated charcoal

The efficacy of a highly activated charcoal in preventing the morphologic effects of T-2 toxin was examined in female rats. T-2 toxin at 25 mg/kg (6 x LD50) was given orally to all rats. Half the rats also received the charcoal, at a dose of 9 ml/kg and a concentration of 104 mg/ml, while the other half received water. A charcoal-treated rat (T-2 toxin + charcoal) was killed at the time of death of each positive control animal (T-2 toxin alone). Severe necrosis was seen in the spleen, thymus, stomach, small intestine, liver and adrenal glands of the positive controls (T-2 toxin alone). Lesions were absent or minimal in the paired charcoal-treated rats (T-2 toxin + charcoal).

Fenvalerate/N,N-diethyl-m-toluamide (Deet) toxicosis in two cats

Toxicosis attributable to fenvalerate and N,N-diethyl-m-toluamide (Deet) exposure was suspected in 2 cats. Clinical signs of toxicosis developed within 4 to 6 hours of dermal application of the pesticide. Clinical signs of toxicosis seen in both cats included hypersalivation, ataxia, and depression. In addition, seizures were seen in 1 cat. Both cats died. Analysis of skin, kidney/urine, liver, and brain tissues confirmed the presence of fenvalerate and Deet. The pyrethroid fenvalerate and the insect repellent Deet are used for the control of fleas and ticks on cats. Suspected fenvalerate/Deet toxicosis in cats is associated with tremors, hypersalivation, ataxia, vomiting, depression, and seizures.

Acute aflatoxicosis in feeder pigs, resulting from improper storage of corn

Aflatoxicosis was diagnosed in 600 feeder pigs, of which 400 died, 150 were destroyed, and 50 were marketed. The pigs were exposed to 2,500 to 3,500 micrograms of aflatoxins/kg of feed. Drought-stressed damaged corn infected with Aspergillus flavus was stored under ambient conditions in a glass-lined silo, and this storage environment provided conditions that favored rapid fungal growth and mycotoxin production.

Enterohepatic circulation of T-2 toxin metabolites in the rat

The enterohepatic circulation of T-2 toxin and its conjugated metabolites was examined in bile duct-cannulated male rats. Rats administered tritiated T-2 toxin intraduodenally (id) eliminated 44.65% and 57.25% of the administered dose in the bile within 4 and 8 hr post-dosing, respectively. TLC profiles of the T-2 metabolites were similar after intravascular and id administration. The major metabolites detected were 3'-OH-hydroxytryptamine-2 (HT-2), glucuronic acid conjugates, T-2 tetraol (TOL), 4-deacetylneosolaniol (4-DN), and HT-2. Tritium-labeled glucuronides obtained from the bile of rats administered [3H]T-2 toxin intravascularly were extracted and purified using C-18 and silica column chromatography. Enzymatic hydrolysis followed by TLC and GC/MS indicated that the aglycone portion of the glucuronides were composed of 3'-OH HT-2, HT-2, 4-DN, and TOL. After id administration of the glucuronides the rats eliminated 6.01% (4 hr) and 11.86% (8 hr) of the dose in the bile. No free metabolites of T-2 toxin were detected in the bile of any animals administered the purified glucuronides. Oral treatment of the rats with the beta-glucuronidase inhibitor, saccharolactone, did not produce a significant decline in the amount of radioactivity recovered in the bile following administration of the tritium-labeled glucuronides. These studies substantiate the enterohepatic circulation of T-2 toxin metabolites.

Evaluation of a superactivated charcoal paste and detergent and water in prevention of T-2 toxin-induced local cutaneous effects in topically exposed swine

T-2 toxin (6 mg) dissolved in 90% DMSO was topically applied to nine 9-cm2 sites on the dorsum of each of nine young, crossbred, specific pathogen-free, female pigs, 20.6 +/- 1.9 kg in weight. A superactive charcoal paste (SAC) and/or a soap-and-water wash (SOAP) was applied to eight of the T-2-exposed sites on each animal. These treatments were applied at various times postexposure ranging from 5 to 65 min. The site that received T-2 alone served as a positive control. DMSO was applied to a tenth site on each pig as a negative control. Animals were killed 1, 3, or 6 days after treatment. Skin lesions were examined and graded grossly and histologically. No adverse systemic clinical signs were observed in any of the animals. Marked reddening and slight swelling of the T-2 toxin-treated positive control sites were present throughout the study. Ulceration of this site was first noted on Day 3. All therapeutic regimens effectively reduced lesion severity resulting from T-2 toxin application. Significant differences in relative effectiveness were also seen between treatments. In each significant pair, the ordering of mean lesion severity was SAC/SOAP less than SAC or SOAP and SOAP less than SAC. As a single treatment, SOAP appears to be more effective than SAC in reducing lesion severity. These results failed to provide unequivocal evidence of an additive therapeutic effect when SAC and SOAP were used sequentially on the same site.

Cottonseed meal (gossypol) toxicosis in a swine herd

Cottonseed meal (CSM) that contained a high concentration of free gossypol was inadvertently used as a protein supplement, without appropriate iron supplementation, for a swine herd in Illinois. Fifty percent of 300 grower and finishing swine died, and an additional 20% became ill during a 4- to 6-week period. Clinical signs included respiratory distress and abdominal distention. At necropsy, the hearts were diffusely pale, flaccid, and rounded because of dilatation of all 4 chambers, the livers were large and congested, and hydropericardium, hydrothorax, and ascites were evident. Histologic changes consisted of diffuse myocardial fiber atropy with perinuclear vacuolation, and multifocal myocardial and skeletal muscle necrosis. Changes in the liver included marked centrilobular congestion, loss of hepatocytes, and fatty degeneration. Differential diagnoses included monensin, selenium, and gossypol toxicoses, and vitamin E/selenium deficiency. Analyzed feed samples did not contain monensin. Feed selenium concentrations ranged from 428 to 1,513 micrograms/kg, and iron concentrations from 160 to 180 mg/kg. Cottonseed meal (3 to 10%) was detected by feed microscopy. A sample of the 40% protein supplement contained 19% CSM and 1,300 mg of free gossypol/kg, whereas feed samples contained 200 to 400 mg of free gossypol/kg. The history, clinical signs, pathologic findings, and feed analyses were compatible with a diagnosis of gossypol toxicosis. Cottonseed meal, a high-protein supplement used widely in southern United States, may contain gossypol (a polyphenolic binaphthalene pigment), which in its free form is especially toxic to simple-stomached animals. If CSM is used, supplementation with ferrous sulfate is recommended at a 1:1 weight ratio with free gossypol, up to 400 mg of FeSO4/kg.

Hematologic changes induced by intravenous administration of diacetoxyscirpenol in pigs, dogs, and calves

Diacetoxyscirpenol (DAS) was given IV to pigs (0, 0.5, and 1.0 mg/kg of body weight), cattle (0 and 0.5 mg/kg), and dogs (0 and 0.5 mg/kg). Blood was collected and hemograms were done at 0.5-hour intervals for 8 hours. The animals were euthanatized at 8 hours after treatment, and bone marrow samples were taken and examined by light microscopy. Moderate to severe necrosis of bone marrow hematopoietic elements was found in animals given DAS. The sequential increase in the type and number of abnormal cells in the blood suggested a successive destruction of the hematopoietic elements. A marked left shift in the neutrophil population was found in animals given DAS. Metarubricytes and large platelets were found in the blood of animals given DAS. Lymphocytes were replaced with immature cells. Pathologic changes were most severe in the pigs given a dosage of 1.0 mg of DAS/kg. The order of species sensitivity to DAS was pigs greater than dogs much greater than cattle.

Dinoseb toxicosis in two dogs

Two male English Setters were noticed to be breathing rapidly, hyperexcitable, and atactic after roaming a rural area for 2 hours. Both dogs' cost were stained with yellow liquid. One dog died while en route to the veterinarian. Treatment was begun for the surviving dog for what was initially diagnosed to be organophosphorus or carbamate insecticide toxicosis. Before the diagnosis could be confirmed, the second dog died. The yellow liquid on the dogs' skin was identified as dinoseb in high concentrations. Dinoseb is an acutely toxic, substituted dinitrophenolic herbicide believed to act as an uncoupler of electron transport from oxidative phosphorylation.

Tissue residues of diacetoxyscirpenol in pigs and calves after intravenous dosing

Pigs (n = 19) were given 0, 0.1, 0.5, or 1 mg of diacetoxyscirpenol (DAS)/kg of body weight, and heifers (n = 7) were given 0 or 0.5 mg of DAS/kg. Animals were anesthetized and exsanguinated 8 hours after administration of DAS, and liver, kidney, skeletal muscle, mesenteric lymph node, and spleen were analyzed for DAS. Diacetoxyscirpenol was not detected in tissues from animals not given DAS. All tissues from pigs and calves given DAS contained at least traces (less than or equal to 10 ng/g of tissue) of DAS.

The role of intestinal microflora in the metabolism of trichothecene mycotoxins

The role of faecal and intestinal microflora on the metabolism of trichothecene mycotoxins was examined in this study. Suspensions of microflora obtained from the faeces of horses, cattle, dogs, rats, swine and chickens were incubated anaerobically with the trichothecene mycotoxin, diacetoxyscirpenol (DAS). Micro-organisms from rats, cattle and swine completely biotransformed DAS, primarily to the deacylated deepoxidation products, deepoxy monoacetoxyscirpenol (DE MAS) and deepoxy scirpentriol (DE SCP). By contrast, faecal microflora from chickens, horses and dogs failed to reduce the epoxide group in DAS and yielded only the deacylation products, monoacetoxyscirpenol (MAS) and scirpentriol (SCP), in addition to unmetabolized parent compound. Intestinal microflora obtained from rats completely biotransformed DAS to DE MAS, DE SCP and SCP; and T-2 toxin to the deepoxy products, deepoxy HT-2 (DE HT-2) and deepoxy T-2 triol (DE TRIOL). Rat intestinal microflora also biotransformed the polar trichothecenes, T-2 tetraol and scirpentriol, to their corresponding deepoxy analogues. Deepoxy T-2 toxin (DE T-2) was synthesized from T-2 toxin and demonstrated to be 400 times less toxic than T-2 toxin in the rat skin irritation bioassay and non-toxic to mice given 60 mg/kg ip, demonstrating that epoxide reduction is a significant single step detoxification reaction for trichothecene mycotoxins.

Experimental T-2 toxicosis in swine following inhalation exposure: clinical signs and effects on hematology, serum biochemistry, and immune response

Nine- to ten-week-old, male castrated, specific pathogen-free derived pigs, weighing 34 to 42 kg, were exposed to a T-2 toxin aerosol (390 micrograms/liter, 1.5 microM mass median aerodynamic diameter) for a time period which allowed an amount equivalent to 8 mg/kg to be nebulized (six pigs). Control animals (five pigs) were exposed to an equivalent amount of the nebulized vehicle. Pigs were immunized subcutaneously with sheep red blood cells on Days 0 and 21. Whole blood and serum samples were taken periodically for clinical pathologic and immunologic studies. Pigs were closely observed, and daily rectal temperatures and weekly weights were measured. The T-2-treated pigs vomited and exhibited cyanosis, anorexia, lethargy, lateral recumbency, slightly elevated rectal temperature, and depressed body weight gain. The lymphocyte count decreased while the neutrophil count increased. The concentrations of total serum protein and hemoglobin declined. There was a marked increase in serum alkaline phosphatase activity on Day 1, followed by a marked and persistent decrease. Mitogen-induced (Con A, PHA, and PWM) blastogenic responses of peripheral blood mononuclear cells and hemagglutination titers to SRBC were also transiently decreased. Thus, inhalation exposure of pigs to a sublethal dose of T-2 toxin caused clinical signs of toxicity and adverse effects on clinical pathologic parameters and immune responses; however, most of these effects were short-lived. The changes described in our study resemble those reported in pigs given T-2 toxin by intravascular injection.

Gas Chromatographic Screening Method for T-2 Toxin, Diacetoxyscirpenol, Deoxynivalenol, and Related Trichothecenes in Feeds

A gas chromatographic method for screening trichothecene mycotoxins in feeds is described. Feed is extracted with acetonitrile-water, and the toxins are purified with charcoal-alumina-Celite, Florisil, and silica mini-columns. Deoxynivalenol (DON), nivalenol (NIV), diacetoxyscirpenol (DAS), T-2 toxin, and their fungal metabolites are hydrolyzed to their corresponding parent alcohols (DON, NIV, scirpentriol, or T-2 tetraol) by alkaline hydrolysis. After derivatization to their pentafluoropropionyl analogs, they are quantitated by capillary gas chromatography with electron capture detection. Identity can be confirmed and sensitivity can be increased by using negative chemical ionization mass spectrometry with no additional sample workup. Recoveries of DAS, DON, and T-2 toxin averaged, respectively, 80, 65, and 85% in corn; 84, 65, and 88% in soybeans; and 70, 57, and 96% in mixed feeds at concentrations ranging from 0.1 to 2.0 ppm. Recoveries of 15-monoacetoxyscirpenol (MAS), HT- 2, NIV, and T-2 tetraol were 97, 97, 86, and 56%, respectively, in corn at a concentration of 0.25 ppm. A detection limit of 0.02 ppm in corn, soybeans, and mixed feeds, and 0.05 ppm in silages is estimated.

Gas chromatographic screening method for T-2 toxin, diacetoxyscirpenol, deoxynivalenol, and related trichothecenes in feeds

A gas chromatographic method for screening trichothecene mycotoxins in feeds is described. Feed is extracted with acetonitrile-water, and the toxins are purified with charcoal-alumina-Celite, Florisil, and silica mini-columns. Deoxynivalenol (DON), nivalenol (NIV), diacetoxyscirpenol (DAS), T-2 toxin, and their fungal metabolites are hydrolyzed to their corresponding parent alcohols (DON, NIV, scirpentriol, or T-2 tetraol) by alkaline hydrolysis. After derivatization to their pentafluoropropionyl analogs, they are quantitated by capillary gas chromatography with electron capture detection. Identity can be confirmed and sensitivity can be increased by using negative chemical ionization mass spectrometry with no additional sample workup. Recoveries of DAS, DON, and T-2 toxin averaged, respectively, 80, 65, and 85% in corn; 84, 65, and 88% in soybeans; and 70, 57, and 96% in mixed feeds at concentrations ranging from 0.1 to 2.0 ppm. Recoveries of 15-monoacetoxyscirpenol (MAS), HT-2, NIV, and T-2 tetraol were 97, 97, 86, and 56%, respectively, in corn at a concentration of 0.25 ppm: A detection limit of 0.02 ppm in corn, soybeans, and mixed feeds, and 0.05 ppm in silages is estimated.

Chemical Contaminants: Their Metabolism and their Residues

Chemical contaminants which food animals may be exposed to include agricultural chemicals (e.g. insecticides, herbicides, fungicides, fumigants), industrial chemicals, metals and natural toxins (e.g. mycotoxins, phytotoxins, bacterial toxins). In the past, most intoxications of food animals resulted from natural toxicants. However, rapid development and usage of synthetic chemicals, while greatly benefitting society, have also provided new sources of potential chemical contamination. Various sources of contamination exist, but generally at least 80% of all residues in food animals are estimated to occur through the feed. Residues from water contamination or other sources occur less frequently. This paper reviews the sources, metabolism and residue problems created by various contaminants and outlines factors and therapeutic approaches utilized in alleviating some of the common chemical residues in food animals.

Comparative in vitro metabolism of T-2 toxin by hepatic microsomes prepared from phenobarbital-induced or control rats, mice, rabbits and chickens

Hepatic microsomes were prepared from phenobarbital (PB)-treated and control rats, mice, rabbits and chickens and were incubated with T-2 toxin (100 micrograms/mg microsomal protein). Additional microsomes from PB-induced animals were incubated with T-2 toxin and the esterase inhibitor paraoxon (PA) at 2.5 nmol/mg microsomal protein. The major metabolite in microsomal preparations from both control and PB-induced rats, rabbits and mice was HT-2. In microsomes isolated from PB-treated chickens, 3'-hydroxy T-2 was the major metabolite, but 30 and 79% of the added T-2 toxin remained unmetabolized at 60 min in incubations from PB-induced and control birds, respectively. The percentage of hydroxylated metabolites formed in the microsomal preparations of the four species studied was significantly increased following PB treatment compared with the non-treated controls. The addition of PA to the incubation system effectively inhibited the hydrolysis of the ester groups in T-2 toxin, resulting in 1.4- and 1.25-fold increases in the percentage of 3'-hydroxy T-2 in the mouse and rat microsomal samples, respectively. In the rabbit microsomal preparations, 3'-hydroxy T-2, which was not detected in the absence of PA, represented 11% of the added substrate in the PB/PA incubation samples. Addition of PA did not cause a significant change in the amount of 3'-hydroxy T-2 formed in chicken microsomal samples, since competition between hydrolysis and hydroxylation pathways for the T-2 toxin substrate was not an important factor in this species. Two new metabolites, designated RLM-2 and RLM-3 were detected in chicken, rat and mouse microsomal preparations. On the basis of gas chromatography/mass spectrometry data, the compounds were tentatively identified as isomers of 3'-hydroxy T-2.

Distribution of blood flow to the gastrointestinal tract of swine during T-2 toxin-induced shock

Swine (6 per group) were used to study gastrointestinal blood flow during T-2 toxin-induced shock. Low- and high-dose groups were given T-2 toxin at 0.6 or 2.4 mg/kg via the pulmonary artery; controls were given the ethanol vehicle. Radiolabeled microspheres were administered into the left atrium to assess organ blood flow predosing and at 90-min intervals for 6 hr. Gastric blood flow decreased in both T-2 groups, and at 6 hr the high-dose group's value was 17% of the predose value. In the low-dose group, the lowest gastric blood flow (30% of predose) was observed 3 hr postdosing. Small-intestinal blood flow of the control group declined to 64% of the predose value. In the high-dose group, small-intestinal blood flow at 3 hr was 174% of predose, followed by a reduction to 62% at 6 hr, coinciding with a severe decline in cardiac output. Small-intestinal blood flow of the low-dose group was 159% of predose at 1.5 hr, then declined to the control value. The high-dose group's large-intestinal blood flow increased to 177% of predose at 3 hr, then declined to 66% at 6 hr. The low-dose group's large-intestinal blood flow increased to 200% of the predose value. The severe decline in gastric blood flow is probably related to the development in swine (given high doses of T-2 toxin) of a grossly bright red gastric fundus, with histologic evidence of vascular congestion and mucosal deterioration.(ABSTRACT TRUNCATED AT 250 WORDS)

The toxicity of T-2 toxin in swine following topical application. II. Effects on hematology, serum biochemistry, and immune response

T-2 toxin at 0 (6 pigs) or 15 mg/kg (8 pigs) in 0.75 ml of dimethyl sulfoxide was topically applied to 9- to 10-week-old, male castrated, specific-pathogen-free derived pigs which were immunized subcutaneously with sheep red blood cells (SRBC) on Days 0 and 21. Whole blood and serum samples were taken periodically for clinical pathologic and immunologic evaluations. The pigs were observed daily and weighed weekly; their rectal temperatures were measured periodically. The T-2-treated pigs displayed anorexia, lethargy, posterior weakness and paresis, persistent high fever, and reduced body weight gain. Prominent neutrophilia, decreased serum glucose, albumin, and alkaline phosphatase activity, and increased serum globulin were seen in the T-2-treated group. The responses of enriched peripheral blood mononuclear cells to mitogens concanavalin A, phytohemagglutinin, and pokeweed mitogen of the T-2-treated group were significantly lower than those of the control group both at early (3 to 5 days) and late (20 to 28 days) postdosing intervals. No significant effects were noted in the hemagglutination titer to SRBC. Thus, in addition to the severe local dermal injury reported previously, topical exposure of swine to a sublethal dose of T-2 toxin, 15 mg/kg, can cause significant systemic effects on parameters such as body weight gain, rectal temperature, hematology, serum biochemistry, and cellular immune response.

The toxicity of T-2 toxin in swine following topical application. I. Clinical signs, pathology, and residue concentrations

T-2 toxin at 0 or 15 mg/kg in 0.75 ml dimethyl sulfoxide was topically applied to 11- to 12-week-old specific-pathogen-free derived crossbred female pigs. Animals were killed on Days 1, 3, 7, or 14 after treatment. Clinical signs and morphologic changes in the skin and internal organs, as well as the residual concentrations of T-2 toxin and its metabolites in plasma, bile, urine, skin, and subcutaneous tissue, were examined. The T-2-treated pigs had signs of lethargy, anorexia, posterior weakness or paresis, and persistent fever. The skin at the site of application was red and swollen initially and progressively became dark red and then purple. By Day 7, at the margin of the exposed area, clefts had formed and were covered by serosanguinous exudate. By Day 14, the affected skin was focally separated from the underlying tissue and covered by a thick scab. The initial skin lesions were characterized as a spongiotic dermatitis and were located mainly in the dermal papillae and stratum germinativum of the epidermis. These lesions progressed to a locally extensive necrotizing dermatitis between Days 3 and 7 that was still evident at Day 14. Healing began on Day 7 and was more prominent on Day 14. Morphologic changes in the internal organs were minimal. They consisted of necrosis of single cells in the follicles of lymphoid tissues and in the exocrine pancreas.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of a general therapeutic protocol for the treatment of acute T-2 toxicosis in swine

T-2 toxin, a trichothecene mycotoxin suspected of being used as a chemical warfare agent, was administered iv to swine at a dose of 3.6 mg/kg body weight (iv LD50 approximately 1.2 mg/kg). Four different therapeutic protocols were assessed for their efficacy in the treatment of the resultant acute T-2 toxicosis syndrome. One therapeutic protocol included the combined use of metoclopramide, activated charcoal, magnesium sulfate, dexamethasone sodium phosphate, sodium bicarbonate and normal saline. The other 3 protocols utilized the same agents less 1 of the following: the combination of activated charcoal and magnesium sulfate, sodium bicarbonate, or normal saline. All 4 treatment groups showed improved survival times compared to a positive T-2 control group. Within the limits of the study, it would appear that the removal of activated charcoal and magnesium sulfate was most detrimental to the T-2 toxin-dosed swine.

Pharmacokinetics of diacetoxyscirpenol in cattle and swine: effects of halothane

In swine and cattle given 0, 0.1, or 0.5 and 0, 0.5 mg of diacetoxyscirpenol (DAS)/kg of body weight, IV, respectively; DAS had a large volume of distribution and total body clearance. The shortness of the interval between halothane and DAS exposures significantly (P greater than 0.05) decreased DAS biotransformation. Urinary excretion of DAS as a parent compound was not an important route of elimination. In swine and cattle, DAS was transformed by sequential deacetylation to monoacetoxyscirpenol and scirpentriol.

Experimental T-2 toxicosis in swine. III. Morphologic changes following intravascular administration of T-2 toxin

The gross and microscopic changes in swine following a single intravascular (iv) dose of T-2 toxin are described and evaluated quantitatively. T-2 toxin, in 70% ethanol, was given iv at 0 (5 pigs), 0.6 (5 pigs), 1.2 (1 pig), 4.8 (5 pigs), or 5.4 (2 pigs) mg/kg to 40 to 60 kg female crossbred pigs. The 4.8 and 5.4 mg/kg group pigs died between 5 and 10.5 hr after treatment, while the 0, 0.6, and 1.2 mg/kg pigs were killed at 24, 24, and 12 hrs after treatment, respectively. Morphologic examination was performed at the gross and light microscopic levels. In addition, a quantitative evaluation of microscopic changes present in lymphoid tissues and intestinal tract was performed using a semiquantitative scoring system. Gross lesions in the T-2-treated pigs consisted of edema, congestion, and hemorrhage of the lymph nodes and pancreas; congestion and hemorrhage of the gastrointestinal mucosa, subendocardium, adrenal gland, and meninges; and edema of the gall bladder. Histologic examination confirmed the gross observations. Additional microscopic lesions included widespread degeneration and necrosis of the lymphoid tissues as well as of the surface and crypt epithelium of the gastrointestinal mucosa; mild scattered necrosis of pancreatic acinar cells, myocardium, bone marrow cells, adrenal cortical cells, and tubular epithelium of renal medulla; and mild interstitial pneumonia. A dose-dependent increase in lesion severity was observed except for the pancreatic lesion which was slightly more apparent in the pigs from the 0.6 mg/kg group. These findings indicate that T-2 toxin-induced lesions in the lymphoid tissues and gastrointestinal tract of pigs are similar to those of other species the pancreas and heart should be considered as additional target organs in the pig, and both rapidly dividing cells and those with little or no turnover are damaged by T-2 toxin.

Experimental T-2 toxicosis in swine following inhalation exposure: effects on pulmonary and systemic immunity, and morphologic changes

Thirty-four, 9- to 11-week-old, male castrated, crossbred, specific pathogen-free derived pigs were exposed to a T-2 toxin aerosol at a nebulized dose of 0 or 9 mg/kg in pairs, each pair consisting of 1 control and 1 T-2 treated pig which were exposed on the same day. Twenty to 30% of the toxin (1.8 to 2.7 mg/kg) was retained by the pigs. Five pairs were killed on each of 1, 3 and 7 days after dosing. Two pairs of pigs were designated as a 0.33-day group when one T-2 treated pig died and the other was killed in a moribund state at 8 to 10 hours after dosing. The pulmonary and systemic immunity and morphologic changes of the lungs and other organs were examined. Bronchoalveolar lavage was performed to obtain alveolar macrophages (AM) and pulmonary lymphocytes (PL). The phagocytic ability of AM and mitogen-induced blastogenic responses of enriched PL and peripheral blood lymphocytes were evaluated. Clinically, all of the T-2 treated pigs vomited and were cyanotic, anorexic, lethargic and laterally recumbent. In the 0.33-, 1-, and 3-day T-2 treated pigs, there was a marked reduction in AM phagocytosis and mitogen-induced blastogenic responses of PL but not of peripheral blood lymphocytes. Mild to moderate, multifocal interstitial pneumonia was seen in the majority of the T-2 treated pigs. In pigs dying following inhalation of T-2 toxin, there was a more severe pneumonia, as well as marked necrosis of lymphoid tissues, severe necrohemorrhagic gastroenteritis and edema of the gall bladder wall, and multifocal necrosis of the heart and pancreas. Thus, inhalation exposure to T-2 toxin can result in clinical signs and morphologic changes resembling those reported previously in pigs given T-2 toxin intravascularly (iv) at a dose of 1.2 mg/kg (approximate LD50) or greater, as well as death. Mild pulmonary injury as well as transient impairment of pulmonary immunity was present in pigs surviving inhalation exposure.

Metabolism of three trichothecene mycotoxins, T-2 toxin, diacetoxyscirpenol and deoxynivalenol, by bovine rumen microorganisms

The three trichothecene mycotoxins T-2 toxin, diacetoxyscirpenol (DAS) and deoxynivalenol (DON) were incubated in vitro for 12, 24 and 48 h with rumen microorganisms obtained from a fistulated dairy cow. Gas chromatographic and gas chromatographic-mass spectrometric analyses of extracts indicated all three toxins were biotransformed to a variety of deepoxy and deacylated products. DON was partially converted to a product identified as deepoxy DON. DAS was rapidly converted to four products including 15-monoacetoxyscirpenol (MAS), scirpentriol and two new compounds identified as 15-acetoxy-3 alpha,4 beta-dihydroxytrichothec-9,12-diene (deepoxy MAS) and 3 alpha,4 beta,15-trihydroxytrichothec-9,12-diene (deepoxy scirpentriol). T-2 toxin was also completely biotransformed to the products HT-2, T-2 triol and two new metabolites identified as 15-acetoxy-3 alpha,4 beta-dihydroxy-8 alpha-(3-methylbutyryloxy) trichothec-9,12-diene (deepoxy HT-2) and 3 alpha,4 beta,15-trihydroxy-8 alpha-(3-methylbutyryloxy)trichothec-9,12-diene (deepoxy T-2 triol).

Therapeutic efficacy of superactive charcoal in rats exposed to oral lethal doses of T-2 toxin

Superactive charcoal, a compound known to complex with many toxins, was evaluated in this study for its effectiveness in preventing death in rats given an oral lethal dose of 8 mg/kg body weight of T-2 toxin. The median effective dose of oral superactive charcoal in preventing deaths in rats was 0.175 g/kg body weight. Concurrent use of cathartics, such as sorbitol, magnesium sulfate and sodium sulfate, to facilitate removal of the superactive charcoal:T-2 toxin complex formed in vivo did not enhance the survival rates of rats. One gram per kilogram body weight oral superactive charcoal enhanced survival times and survival rates in rats given 8 mg/kg of T-2 toxin as late as 3 hr after the T-2 toxin was administered. Some benefit in survival rate may be derived from giving the superactive charcoal as late as 5 hr after the T-2 toxin.

Assessment of potential therapies for acute T-2 toxicosis in the rat

The efficacy of a variety of approaches for the treatment of animals with acute T-2 toxicosis was assessed utilizing young female rats. A single large dose of the water soluble salt of methylprednisolone significantly prolonged survival times in T-2 toxin treated animals. The use of diltiazem hydrochloride, dazemgrel, N-acetylcysteine, dimethyl sulfoxide, adenosine triphosphate (ATP), ATP combined with magnesium chloride, ascorbic acid, and aprotinin did not prolong survival times at the dosages administered. Trichodermin, a trichothecene similar in structure and biochemical activity to T-2 toxin but much less acutely toxic, had a detrimental effect on survival times whether given 1 hr prior to or after T-2 toxin.