ABSTRACT
The chicken embryo, brine shrimp (Artemia salina) and selected bacteria (Staphylococcus epidermidis, Micrococcus flavus, and Bacillus subtilis) were evaluated as alternative test systems for the determination of paralytic shellfish poisoning toxicity (saxitoxin). Dose levels ranging from 0.045 to 0.3 microgram were administered to the developing embryo through the air cell at either 0 or 96 h following incubation. Embryos dosed 96 h after incubation were the most sensitive, with 100% mortality at the 0.11-microgram dose level 24 h following exposure. Embryo mortality was 42% at to 0.3-microgram dose level when the toxin was administered at 0 h. Some embryonic malformations were observed in the 0-h treatment group. Brine-shrimp larvae were sensitive to saxitoxin at a dose level of 5 micrograms. A dose response based on mortality was apparent only 48 h after dosing. Limited growth inhibition was observed with the bacteria tested at concentrations between 0.0035 and 0.35 microgram and 0.35 microgram/well.
Subject(s)
Saxitoxin/toxicity , Animals , Bacillus subtilis/drug effects , Bacteriological Techniques , Chick Embryo , Decapoda/drug effects , Micrococcus/drug effects , Staphylococcus epidermidis/drug effectsABSTRACT
Primary cultures of rat hepatocytes were used to determine unscheduled DNA synthesis (UDS) and cytotoxicity of purified 4-deoxynivalenol (vomitoxin), a trichothecene mycotoxin produced on cereal grains by fungi of the genus Fusarium. Nontoxic and toxic doses of deoxynivalenol, 0.1 to 1000 micrograms/ml, did not significantly increase UDS as measured by net grains per nucleus, net grains per nuclear area or percentage of cells incorporating greater than or equal to 5, 6, 10 or 20 grains per nucleus. Evidence of cytotoxicity, manifested as a reduction in cell number in autoradiographs, pyknotic nuclei or vacuolated cytoplasm, was observed in hepatocytes treated with deoxynivalenol concentrations of 5 micrograms/ml and above. These findings suggest that the cellular toxicity of deoxynivalenol may not be mediated by a DNA-damaging event in cultured hepatocytes. An increased percentage of large-sized nuclei was also found to be associated with toxic doses of deoxynivalenol as well as 2-acetylaminofluorene used as the positive control.
Subject(s)
DNA Repair/drug effects , Sesquiterpenes/toxicity , Trichothecenes/toxicity , 2-Acetylaminofluorene/toxicity , Animals , Cell Nucleus/drug effects , DNA/biosynthesis , In Vitro Techniques , Liver/drug effects , Liver/metabolism , Liver/ultrastructure , Male , Rats , Rats, Inbred StrainsABSTRACT
Computed tomography, utilized in conjunction with a calibrated phantom containing a set of reference densities (K2HPO4 and water), is capable of determining the mineral content of the trabecular bone of the spine with an accuracy of about 6% of the ash weight of the vertebrae scanned (specimen studies). Other modalities measure a composite of cortical and trabecular bone. Computed tomography is capable of exclusively measuring the mineral content of the trabecular bone of the spine, where the earliest and most pronounced changes of spinal osteoporosis occur. Quantitative computed tomography measurements are useful for a precise and objective assessment of the spinal mineral content and its changes with age, disease, and drugs.
Subject(s)
Aging , Bone and Bones/metabolism , Minerals/metabolism , Spine/diagnostic imaging , Tomography, X-Ray Computed , Adult , Aged , Bone Resorption/diagnostic imaging , Female , Humans , Male , Menopause , Middle Aged , Osteoporosis/diagnostic imaging , Spinal Diseases/diagnostic imagingABSTRACT
Computed tomography was utilized to measure the bone mineral content of the spinal trabecular bone in 96 osteoporotic women. A significant overlapping was found between the values obtained for these patients and the age-matched normal values. Sixty-six percent had bone mineral content values below the fifth percentile for age-matched normals. Eighty-five percent of those with vertebral fractures had bone mineral content values below the fifth percentile for normal premenopausal women (fracture threshold). It is suggested that diagnosis of osteoporosis be made when the spinal bone mineral content value is below the fracture threshold.
Subject(s)
Fractures, Spontaneous/diagnostic imaging , Osteoporosis/diagnostic imaging , Spinal Injuries/diagnostic imaging , Tomography, X-Ray Computed , Adult , Aged , Aging , Bone and Bones/metabolism , Female , Fractures, Spontaneous/etiology , Humans , Menopause , Middle Aged , Minerals/metabolism , Osteoporosis/complications , Prospective Studies , Spinal Injuries/etiologyABSTRACT
En 207 ninos contaminados por via percutanea con acetato de fenilmercurio por contacto con panales procesados en lavanderias, se realizaron como estudio de rutina radiografias de metafisis de rodillas y munecas observandose en 116 de ellos (56%) lineas de detencion del crecimiento de Park. La frecuencia de esta observacion sugiere que la exposicion repetida al mercurio condiciona episodios de detencion del crecimiento oseo seguidos de etapas de normalizacion
Subject(s)
Infant, Newborn , Infant , Child, Preschool , Humans , Comparative Study , Growth Disorders , Bone Diseases, Developmental , Mercury Poisoning , RadiographyABSTRACT
En 207 ninos contaminados por via percutanea con acetato de fenilmercurio por contacto con panales procesados en lavanderias, se realizaron como estudio de rutina radiografias de metafisis de rodillas y munecas observandose en 116 de ellos (56%) lineas de detencion del crecimiento de Park. La frecuencia de esta observacion sugiere que la exposicion repetida al mercurio condiciona episodios de detencion del crecimiento oseo seguidos de etapas de normalizacion
