RESUMEN
Lead acetate was fed to 4 groups of 2 horses each to study chronic lead intoxication. A 5th group of 3 horses was maintained as controls. The leas was fed in capsules, with the minimum dosage of 6.25 mg/kg/day of lead as lead acetate (group I). The dose was increased from group I through group IV in an approximate geometric series, with each group being given about 125% of the dose given the previous group. These doses were given for 105 days, a period designated as phase 1. Since clinical signs were not observed after 105 days, the doses were increased and fed for an additional 190 days (days 106 to 295). This period was designated phase 2. The smallest daily dose in phase 2 was set at about 125% of the largest daily dose in phase 1. The doses in each group was increased by about 125% of that of the previous group, as was done in phase 1. Seven horses died or were euthanatized after 18 to 190 days of phase 2 (123 to 295 days after the 1st dose). One horse in group I did not develop any clinical signs of intoxication. Dose-related responses were unnoticed with doses larger than 15.3 mg/kg/day. All horses given lead had increased blood lead and serum iron concentrations. During phase 2, the hematocrit (erythrocyte volume) and hemoglobin contents were depressed. The lead concentration in kidney, liver, spleen, pancreas, brain, bone, and heart was increased in the treated horses. The dose level required to produce lead intoxication was greater than that reported for cattle and that estimated in epizootiologic studies of horses.
Asunto(s)
Enfermedades de los Caballos/inducido químicamente , Intoxicación por Plomo/veterinaria , Animales , Enfermedad Crónica , Femenino , Hemoglobinas/análisis , Enfermedades de los Caballos/sangre , Enfermedades de los Caballos/patología , Caballos , Hierro/sangre , Plomo/sangre , Intoxicación por Plomo/sangre , Intoxicación por Plomo/patología , MasculinoRESUMEN
Ammi majus (bishop's weed) grows on the coastal region of southern United States and in other parts of the world. This plant causes severe photosensitization in livestock and probably contributes to the severe photosensitization outbreaks seen in Texas. Sheep were fed finely ground seed of A majus via stomach tube at dose rates of 1, 2, 4, and 8 g/kg of body weight and exposed to sunlight. The single dose of 8 g/kg produced severe clinical signs (in 24 to 48 hours): cloudy cornea, conjunctivokeratitis, photophobia, and edema of the muzzle, ears, and vulva. Daily dosing at 2 and 4 g/kg produced (in 72 to 96 hours) similar signs, whereas the smallest dose (1 g/kg) produced mild irritation of the muzzle. Pathologic changes included (1) corneal edema and marked neutrophilic infiltration of the cornea and corneal/ciliary process, (2) subacute ulcerative and exudative dermatitis of the skin of ears, muzzle, and vulva, and (3) mild focal tubular degeneration (vacuolar type) of the kidney.
Asunto(s)
Trastornos por Fotosensibilidad/veterinaria , Intoxicación por Plantas/veterinaria , Plantas Medicinales , Enfermedades de las Ovejas/etiología , Animales , Femenino , Trastornos por Fotosensibilidad/etiología , Intoxicación por Plantas/complicaciones , Semillas , OvinosRESUMEN
Feeding Ammi majus to cattle and sheep caused photosensitization in both species. It also caused photosensitization in human beings who had dermal contact with the plant and subsequent exposure to sunlight.
Asunto(s)
Enfermedades de los Bovinos/etiología , Trastornos por Fotosensibilidad/veterinaria , Intoxicación por Plantas/veterinaria , Plantas Medicinales , Enfermedades de las Ovejas/etiología , Animales , Bovinos , Humanos , Trastornos por Fotosensibilidad/etiología , Intoxicación por Plantas/complicaciones , OvinosRESUMEN
Studies with smallhead sneezeweed (Helenium microcephalum DC) indicated that a sesquiterpene lactone, helenalin, is the only significant toxic constituent present. The oral median lethal dose of helenalin for 5 mammalian species was between 85 and 105 mg/kg.