Showing papers in "Veterinary and Human Toxicology in 1991"

Collective human food poisonings by clenbuterol residues in veal liver.

Abstract: Twenty-two patients were reported to complain of tremor, headaches, tachycardia and dizziness 1-3 h after eating veal liver. As clinical symptoms were not suggestive of an infectious cause, the presence of veterinary drug residues was suspected. Clenbuterol, a beta 2-agonist, was being illegally used in cattle because of its anabolizing properties and may explain the observed effects. Assays of clenbuterol in samples of veal liver showed concentrations of 0.375 and 0.500 micrograms/g. To our knowledge, this is one of the first reports of clinical symptoms in humans associated with the consumption of veterinary drug residue-containing food.

Neurotoxicology of pyrethrin and the pyrethroid insecticides.

Abstract: Natural pyrethrin and synthetic pyrethroid insecticides have been considered among the safest classes of insecticides available. Pyrethrins and pyrethroids are classified on the basis of their chemical structures and their toxicologic, neurophysiologic and pharmacologic effects. Cellular effects of pyrethrin and pyrethroid insecticides have been postulated to involve interactions with sodium channels, receptor-ionophore complexes, neurotransmitters, and ATPases. Toxicity is a function of chemical structure, metabolism, route of exposure, and the presence or absence of synergists. Pyrethroid insecticides are neurotoxic, and the development and severity of clinical signs is proportional to the nervous tissue pyrethroid concentration. Type I pyrethroid poisoning in mice and rats produces a syndrome characterized by tremors, prostration and altered startle reflexes. Type II pyrethroid poisoning in mice and rats causes ataxia, convulsions, hyperactivity, choreoathetosis and profuse salivation. A presumptive diagnosis of pyrethrin/pyrethroid poisoning is based upon history of exposure, development of appropriate clinical signs, and chemical analysis for insecticide residues. Treatment of pyrethrin and pyrethroid toxicosis involves basic life support, seizure control when needed, and the prevention of further insecticide absorption.

Hazards in confinement housing--gases and dusts in confined animal houses for swine, poultry, horses and humans.

Abstract: Indoor atmospheres in swine or poultry confinement buildings, horse stalls or human dwellings contain gases, dusts and endotoxin in concentrations significantly in excess of those in outdoor environments. Although concentrations of such constituents differ appreciably between species, many of such differences may be related to differences in indoor mass loading and ventilation, or to the homogeneity of such ventilation. The high protein content of these indoor dust particles suggest they are of animal origin. Their ability to form bacterial colonies and to form or bind endotoxin suggest that the smallest and most respirable particles were manure particles containing enteric bacteria and endotoxin. Respiratory disease in swine, poultry and horses and in the workers who care for them may be caused by increased levels of carbon monoxide, ammonia, hydrogen sulfide, or indoor dust particles from feed and manure. The stagnant air of a well-insulated building causes the most active individual to attract these stagnant pockets, while the tendency of young animals to seek warmth may lead to the formation of additional pockets. Increased ventilation is an expensive solution to the problems associated with indoor air pollution. However, more thorough mixing of indoor air may reduce the effects of these clouds of pollutants.

Atropine intoxication from the ingestion and smoking of jimson weed (Datura stramonium).

Abstract: Anticholinergic effects occur due to jimson weed intoxication. The most common intoxication involves teenagers desiring mind-altering properties from the plant. We report 4 cases of jimson weed intoxication due to ingestion and inhalation (smoking) of jimson weed. Clinicians should be aware of the potential abuse of botanicals such as jimson weed.

Hypersensitivity in humans and exposure to veterinary drugs.

Abstract: There is a small but unquantifiable risk that residues of hypersensitivity-inducing drugs may elicit hypersensitivity reactions in human consumers of food of animal origin. The levels present are unlikely to be sufficient to cause initial sensitization, and this is most likely to occur by therapeutic use in man. However, these levels may occasionally elicit hypersensitivity reactions in previously sensitized patients. The available data suggests that the incidences of such reactions are exceedingly low and the risk can be minimised by the careful use and observance of withdrawal periods. Occupational exposure may present a higher, but again unquantifiable risk which may also be reduced by the production of low-dusting formulations, by the observance of precautionary phrases, and by the use of suitable protective clothing.

Acid-base balance in alcohol users seen in an emergency room.

Abstract: Over 10% of emergency room patients are diagnosed as having alcohol (6.0%) or drug intoxication. In the present study 196 alcohol intoxications treated in a hospital were studied retrospectively; 49.2% of the patients had abnormal acid-base values, alcoholics more often than non-alcoholics (p = 0.04). Mean blood ethanol concentration (BAC) was 310 mg/dl (SD 120); alcoholics had higher concentrations of alcohol. BAC was the higher the lower the serum pH was (p less than 0.002, r = -0.45). The deeper the coma the lower the serum pH (p less than 0.05) and the higher the BAC (p less than 0.0001). Respiratory acidosis (31.7%) was an important finding in those intoxicated. Metabolic acidosis (7.9%) could be explained by the presence metabolites of ethanol in the serum and by decreased extra-cellular fluid volume. Metabolic alkalosis related to vomiting and an extra-cellular fluid volume decrease was found in 7.9% of the patients. Respiratory alkalosis was a rare finding (1.6%). Hypokalemia (22.5%) and hypernatremia (15.3%) were the most important electrolyte changes. Chronic alcoholics had lower serum potassium than had non-alcoholics; 3.6% (n = 7) of the patients had to be intubated. Acid-base disturbances were frequent in adults with alcohol intoxication. Serum pH correlated well with the state of consciousness and the BAC.

An outbreak of Vicia villosa (hairy vetch) poisoning in grazing Aberdeen Angus bulls in Argentina.

Abstract: Vicia villosa (hairy vetch) is used as a forage source in some cattle-producing areas in Argentina. The plant had no previous reports of toxicity in this country. A herd of 33 Aberdeen Angus bulls grazed during 20 days in October on a pasture composed mainly of hairy vetch. Eight animals developed conjunctivitis, rinitis, dermatitis, loss of hair and fever. All of them died within 15 d after the development of signs with a marked loss of body condition. No more animals became sick 5 d after the removal of the herd from the pasture. Serum parameters tested (calcium, phosphorus, magnesium, GOT, alfa-GT and bilirubin) enlarged liver and spleen, generalized hemorrhage in the abomasum, dilated kidneys and multiple pale areas on the heart. Severe necrotizing granulomatous myocarditis, interstitial nephritis, and necrotizing cholangitis were the most striking microscopic changes. Close observation of animals feeding on pastures in which V villosa is dominant is the only prevention.

Pyrethroid insecticides and pregnancy: effect on physical and behavioral development of rats.

Abstract: We investigated the prenatal effects of cyhalothrin exposure on the physical and behavioral development of infant and adult rats. Female rats were treated by dermal exposure with a 0.018% cyhalothrin aqueous solution (1 ml/d) or the cyhalothrin vehicle during their entire pregnancy. The pesticide delayed development of fur, the ear and eye openings and descent of the testes in the offspring. The exploratory behavior of the rats prenatally exposed to cyhalothrin decreased. No differences were observed between control and experimental animals in inhibitory avoidance tasks at 90 d of age in open field activity. Alterations in physical parameters and possible effects of the pesticide on epidermal growth factor and hormonal levels were considered. Since no overt of signs of maternal or neonatal toxicity were observed, the decrease in adult motivational behavior was attributed to a specific effect of the pesticide administered during the prenatal period. We concluded that prenatal cyhalothrin exposure induced subtle and persistent changes in the physical development and behavior of rats.

The toxic effects of cassava (manihot esculenta grantz) diets on humans: a review.

Abstract: The toxic effects of cassava diets on humans were reviewed. Some newspapers in Nigeria have reported deaths associated with cassava meal consumption. The papers looked into the toxic factors in cassava, their causes, the resultant effects on humans, and the reasons why cassava diets became popular in Nigeria. Suggestions were made on how to process cassava to make it safe for human consumption. The reported deaths may have occurred due to improper processing. This may have left traces of hydrogen cyanide in the products and on consumption produced death.

Arsenic poisoning in livestock.

Abstract: Arsenic is an important heavy metal intoxicant to livestock. Arsenical pesticides present significant hazards to animal health. The toxicity of arsenic varies with several factors--its chemical form, oxidation states, solubility. The phenylarsonic compounds are the least toxic and are used as feed additives in swine and poultry rations. However, roxarsone has a higher absolute toxicity than arsanilic acid. The mechanism of action is related to its reaction with sulfhydryl groups values to enzyme function and to its ability to uncouple oxydative phosphorylation. Most animals excrete arsenic quite readily. Toxicoses caused by inorganic and aliphatic organic arsenicals result in a different clinical syndrome than that from the phenylarsonic compounds. Arsenic poisoning may be confused with other types of intoxication. The specific antidote for inorganic arsenical poisoning is dimercaprol (BAL).

Postsurgical mortality secondary to zinc toxicity in dogs.

Abstract: Zinc may be extremely toxic when absorbed from a metallic foreign body retained in the stomach. The most common cause of zinc toxicosis in dogs appears associated with accidental ingestion of copper-coated zinc pennies minted after 1982. In a retrospective literature search, zinc toxicosis due to penny ingestion was reported in 5 dogs, 2 of which died postoperatively, and 1 was euthanatized due to severe multiorgan system failure. In this report, we describe 3 additional cases of zinc toxicosis due to penny ingestion that resulted in a fatal outcome. Two dogs died during the early postoperative period, and another dog was euthanatized 5 d postoperatively due to continued deterioration. These cases emphasize the potential of perioperative complications associated with zinc toxicosis due to penny ingestion and suggest the need for better treatment options to decrease postsurgical mortality associated with this disease entity.

An outbreak of aflatoxicosis in Angora rabbits.

Abstract: An outbreak of aflatoxicosis in Angora rabbits involving a large number of rabbitries was investigated. Mortality was more in weaners than in adults. Affected animals showed anorexia, dullness and weight loss followed by jaundice in terminal stages. Death occurred within 3-4 d of the appearance of clinical signs. Livers were moderately to severely congested, icteric and were hard to cut. Gall bladders were distended and had inspissated bile. Liver sections showed degenerative changes of hepatic cells along with dilatation and engorgement of sinusoids. Bile ducts had mild to severe periportal fibrosis. Focal areas of pseudolobulation and regenerative foci were also predominant. The level of aflatoxin B1 in feed samples from various farms submitted at the time of the investigation varied from 90 to 540 ug aflatoxin B1/kg of feed. Withdrawal of feed and supplementary therapy resulted in gradual disappearance of signs and mortality.

Acute poisoning by lupine seed debittering water.

Abstract: A case of acute poisoning by ingestion of water used to debitter lupineseeds, an exceptional occurrence in human clinics, is reported. The patient showed the anticholinergic syndrome for 48 h, which then subsided spontaneously.

Protection against cyanide toxicity by oral alpha-ketoglutaric acid.

Abstract: The efficacy of orally administered alpha-ketoglutarate (AKG), alone and in combination with n-acetyl-cysteine (NAC), in reducing the lethal effects of injected potassium cyanide was examined in the mouse. A behavioral scoring system was developed to monitor and measure the signs of toxicity associated with cyanide exposure. AKG significantly reduced the lethality of KCN (6.7 mg/kg ip) in a dose-related manner. The protective effect of AKG was observed if given between 10 and 30 min prior to cyanide exposure. NAC increased the protective effect of AKG but did not alter the time course of protection. AKG alone or in combination with NAC significantly reduced the duration of the toxicity associated with cyanide exposure. This study identifies AKG as an orally effective cyanide antagonist. The protective effect of AKG is enhanced by concomitant administration of NAC. Our work also describes a scoring system which quantifies the signs of toxicity associated with cyanide poisoning.

Swainsonine-induced high mountain disease in calves.

Abstract: Swainsonine, an indolizidine alkaloid in the locoweeds (certain species of the Astragalus and Oxytropis genera), was fed to young Holstein bull calves in their milk at high elevation (3090 m), and the incidence of high mountain disease (HMD) was compared with locoweed-fed and control calves. Five of 5 calves fed swainsonine and 5 of 5 calves fed fresh Oxytropis sericea showed outward signs of HMD, which included edema under the jaws, throat area and brisket and gross and microscopic lesions of HMD and locoweed poisoning. Grossly there were HMD lesions, including congestion of the liver, right ventricular hypertrophy, and dilatation and excessive fluid in the thoracic and abdominal cavities. Microscopically, the severe centrilobular lesions in the liver, edema of the pulmonary artery, severe edema and/or fibrosis of the roof of the right atrium were suggestive of HMD. The mild to moderate neurovisceral cytoplasmic foamy vacuolation of selected tissues and cerebellar neuroaxonal dystrophy in all calves fed swainsonine and locoweed were indicative of locoweed poisoning. In control calves, 1 of 6 showed equally severe outward, gross, and microscopic lesions of HMD, but none had any lesions indicative of locoweed poisoning. The ratio of right ventricle to left ventricle wall weights were significantly higher (P = 0.033) for the swainsonine-fed calves (1.4) and the locoweed-fed calves (1.3) compared to the controls (0.9). Scores indicating the severity of HMD from observations prior to necropsy were significantly higher for the swainsonine and locoweed-fed calves compared to controls (P = 0.032).(ABSTRACT TRUNCATED AT 250 WORDS)

2,4-D toxicosis. I: A pilot study of 2,4-dichlorophenoxyacetic acid- and dicamba-induced myotonia in experimental dogs.

Abstract: English Pointer dogs dosed po with encapsulated 2,4-dichlorophenoxyacetic acid (2,4-D) or 2-methoxy-3,6-dichlorobenzoic acid (dicamba) developed varying degrees of myotonia. Dogs given 175 or 220 mg of 2,4-D/kg body weight rapidly developed clinical and electromyographic (EMG) manifestations consistent with a diagnosis of myotonia or pseudomyotonia. Dogs given 2,4-D at 86.7, 43.7 or 8.8 mg/kg body weight developed subclinical manifestations of myotonia detectable only with an electromyograph. The administration of 2,4-D at 1.3 or 1.0 mg/kg body weight failed to produce detectable EMG changes. One dog given dicamba at 86.7 mg/kg body weight developed clinical and EMG manifestations of myotonia similar to those induced by the highest doses of 2,4-D.

Snake venom constituents: biochemistry and toxicology (Part 1).

Abstract: Complicated and mystifying as the snake envenomation process may appear, the toxic principles of snake venoms are biochemical entities that could be isolated, purified and characterized. In this review, the toxicological process of envenomation and the biochemical basis of venom toxicity are presented for those not directly involved in venom research but who nevertheless have an interest in snake venom poisoning.

Snake venom constituents: biochemistry and toxicology (Part 2).

Abstract: : Complicated and mystifying as the snake envenomation process may appear, the toxic principles of snake venoms are biochemical entities that could be isolated, purified and characterized. In this review, the toxicological process of envenomation and the biochemical basis of venom toxicity are presented for those not directly involved in venom research but who nevertheless have an interest in snake venom poisoning.

Major diseases of striped bass and redfish.

Abstract: Diseases of striped bass, their hybrids, and redfish (red drum) are important constraints to the culture of these two species. Since striped bass have been cultured for years the organisms that cause most diseases of these fish are well known, but very little specific disease information exists for redfish. However, it appears that the organisms that cause diseases of striped bass and redfish do not differ greatly from those of other fishes. The most significant viral disease is lymphocystis, but infectious pancreatic necrosis has occurred in striped bass. Vibriosis (Vibrio sp.) and motile Aeromonas septicemia (Aeromonas hydrophila) are the most frequently encountered bacterial diseases. Both species of fish are affected by fungi (usually Saprolegnia) when the fish are injured or stressed. Amyloodinium ocellatum is the most serious protozoan that infects striped bass and redfish, but the other common protozoans (Trichodina, Ichthyophthirius, Cryptocaron, etc.) have also been reported. Treatment of any of these diseases is a problem because of the absence of approved drugs or chemicals for use on striped bass or redfish. The most common therapeutics used on striped bass and redfish are copper sulfate, formalin, salt (in freshwater) and Terramycin.

Effects of dietary factors on antioxidant enzymes in rats exposed to hyperbaric oxygen.

Abstract: To delineate the effect of dietary supplementation with vitamin E (Vit E) alone or in combination with riboflavin (Rib) or selenium (Se) or both, on biological oxidative damage in rat brain and lungs we exposed rats to hyperbaric oxygen (HBO) and measured the activities of glutathione reductase (GSSG-R), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and glucose-6-phosphate dehydrogenase (G-6-PD) prior to or 48 h after exposure. Rats fed the dietary supplements, and a control group maintained on an unsupplemented diet, for 30 d, were each divided into 2 subgroups, of which 1 was exposed to 4.5 absolute atmospheres (ATA) of 100% oxygen for 30 min, hereafter referred to as "exposed". The remaining subgroups were left unexposed. Pre-exposure GSSG-R activity in brain was elevated in all experimentally fed groups (ranging from 23 to 84%) compared with the unexposed control, whereas GSH-Px, G-6-PD and SOD activities were unchanged. The lungs showed significant increases in pre-exposure GSSG-R, ranging from 15 to 28%, and GSH-Px, ranging from 13 to 23%, activities in all the groups fed the supplemental nutrients, except those on Vit E alone. Increases in G-6-PD activity were observed only in those fed supplements of Rib. In most cases exposure to oxygen caused an increase in GSSG-R, GSH-Px and G-6-PD activities. However the increases were higher in the supplemented groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Denatonium benzoate: review of efficacy and safety.

Abstract: The efficacy and toxicity studies on denatonium benzoate are limited and may be subject to varying interpretations when viewed in the context of a potential poisoning situation. Efficacy studies to date in children have shown that in a controlled environment, addition of denatonium benzoate to an otherwise palatable liquid will decrease the volume ingested. Important considerations include the fact that the number of studies are small (two utilizing orange juice as the liquid; one using a dilute liquid detergent), and these studies involved single-test situations wherein the liquid was available to the child for a limited period of time. Inadequate data are available to analyze one orange juice study and in the other study, 7 of 30 children took more than one swallow. Depending on the "pleasantness" of the liquid (color, smell, similarity to 'drinkable' liquids in appearance) prior to addition of denatonium, it is possible that children may take more than one swallow. Toxicity data indicate a low toxicity profile. However, there are significant gaps in our knowledge, especially relating to chronic toxicity in humans, teratogenicity, and human hypersensitivity potential. The role of denatonium benzoate in preventing serious poisonings has yet to be defined. Aversive agents such as denatonium should augment but not replace proven methods of poison prevention including parental education and child-resistant closures. When selecting products for inclusion of denatonium benzoate, consideration should be given to the inherent toxicity of the product as well as the potential for long-term human exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of prenatal pyrethroid insecticide exposure on the sexual development of rats.

Abstract: The prenatal effects of exposure to the insecticide cyhalothrin on the sexual maturation and sexual behavior of rats were investigated. Female rats were dermally treated with 1 ml/day of 0.02% (w/v) aqueous cyhalothrin solution or its vehicle throughout pregnancy. This insecticide administration delayed the age of testicle descent but did not modify the age of vaginal opening. In adulthood, both male and female rat sexual behaviors were not different from vehicle-treated animals. It was concluded that prenatal exposure to cyhalothrin can induce alterations in the development of certain physical characteristics of rats which are not correlated with functional deficiencies in the animals' later life.

Percutaneous in vivo and in vitro absorption of lead.

Abstract: Diffusion tubes were used to measure the degree of in vitro penetration of tetrabutyl lead, lead naphthanate, lead nuolate, lead acetate and lead oxide in excised guinea pig skin and human skin from autopsy. Tetrabutyl lead demonstrated the greatest penetration in skin from both guinea pig and man. Lead nuolate, lead naphthanate and lead acetate followed in descending order in the human tissue. A similar pattern occurred with guinea pig skin in most cases. There were no measurable amounts of lead oxide absorbed in either species. In vivo absorption was measured by applying 300 mg/kg tetrabutyl lead, lead nuolate, lead naphthanate or lead oxide to the shaved backs of guinea pigs for 7 d under occluded wrappings. Tetrabutyl lead was present in tissues in the highest quantities. Lead nuolate was present in greater amounts than lead naphthanate in the liver and kidneys. Lead acetate was the most poorly absorbed with the exception of lead oxide which demonstrated no absorption.

Exposure assessment of consumer products: human body weights and total body surface areas to use, and sources of data for specific products.

Abstract: A thorough understanding of the routes and magnitudes of chemical exposures that consumers experience during the use of a household product is needed as part of a well-founded risk assessment for that product and its components. This review describes some sources of generic consumer data (eg, relevant body weight or total body surface area for a given human age), and exposure-related data (eg, task frequency and duration) for specific product types needed for exposure assessments. The review also contains a discussion of the importance of statistical characterization of the consumer data (eg, does its range follow a normal, log-normal, or other type of distribution?). The importance of examining these data for correlative interactions is emphasized.

Oral and injectable applications of erythromycin in salmonid fish culture.

Abstract: Erythromycin is a macrolide antibiotic effective against Renibacterium salmoninarum, causative agent of bacterial kidney disease in salmonids. Although erythromycin is used on an experimental basis in private and conservation hatcheries, the drug is not registered with the US Food and Drug Administration for use in fish culture. Residues of erythromycin are retained in the tissues of juvenile and adult salmon for some time following administration of oral or injectable forms of the drug, a characteristic that may be important in the drug's efficacy against the slow growing R. salmoninarum pathogen. Before erythromycin can be registered, additional information must be collected about efficacy, toxicity, and environmental consequences of administration.

The effect of cottonseed components on testicular development in pubescent rams.

Abstract: The effect of gossypol on testicular development in rams was examined using 2 experimental approaches. Trial I utilized direct ruminal deposition of gossypol acetic acid (GAA; 95% purity), whereas Trial II compared 2 types of dietary cottonseed, regular and glandless. For Trial I, 18 Polypay or Polypay x Dorset ram lambs, aged 4 to 6 mo, were surgically fitted with rumen cannulae. These 18 ram lambs were divided into groups of 6 which were given either 0, 2.2 or 6.6 mg of GAA/kg body weight daily via gelatin capsules directly into the rumen. All rams in Trial I were slaughtered after 4 or 8 w of treatment to allow recovery of their scrotal contents. The mean testicular weight for the group of rams given 6.6 mg GAA/kg/d was 8% (p less than .05) less than for the rams given 0 mg GAA/kg/d. The caudal epididymal sperm were examined microscopically for percentage of progressively motile sperm and flow cytometrically for mitochondrial function using rhodamine 123 (R123). Differences in sperm motility were not evident among the treatment groups, nor were differences detectable in the 2 major sperm populations, B and C, that were identified by flow cytometry. In Trial II, 21 Polypay and Polypay-Dorset ram lambs, aged 10 mo, were randomly assigned into 3 groups (n = 7) and fed either glandless fuzzy cottonseed (GFC), glandless flake cottonseed (GFL) or regular fuzzy cottonseed (RFC). All rams were fed for 5 w a total daily ration (TDR) equivalent to 3.5% of their body weight daily with 25% being cottonseed. After 8 w the scrotal contents were recovered by castration.(ABSTRACT TRUNCATED AT 250 WORDS)

Predicting outcomes in paraquat poisonings.

Abstract: The purpose of this study was to analyze the factors in patients with paraquat poisoning at admission which were able to predict the chance of survival. From January 1983 to September 1988, 24 patients were admitted to Ramathibodi Hospital because of paraquat poisoning. Nine were male and 15 were female, aged 29.9 +/- 18 y (range from 12 to 73 y). The amount of paraquat ingested was 57.4 +/- 107.9 ml. Patients were treated with Fuller's Earth and forced diuresis. The serum paraquat levels obtained in 15 patients were 0.17 +/- 0.34 ug/ml at 24.7 +/- 6.6 h after ingestion. Seventeen patients (71%) died. A prediction rule was developed by discriminant analysis and multiple logistic linear regression to predict outcome in paraquat poisoning. Age, amount of paraquat ingested, and white blood cell count at admission were identified as positively correlated with mortality. The discriminant function which classified the patients into the expired group if the function was negative, and vice versa, was 0.027 age + 0.022 ingested amount + 0.0002 WBC - 4.06. The model was validated by the jackknife method and prospectively. Seventy-nine percent of patients in the study group were classified correctly when using the jackknife method. Prospectively, The prediction rule correctly classified all 9 newly admitted paraquat poisoning patients. We conclude that age, ingested amount, and white blood cell count at admission are prognostically significant in paraquat poisoning. The prediction rule based on the above prognostic factors can appropriately forecast outcome in paraquat-poisoned patients.