RESUMEN
Wastes derived from the exploitation of stibnite ore deposits were studied to determine their mineralogical, chemical, and environmental characteristics and establish the Sb distribution and the current and long-term risks of Sb mobilization. Representative samples of mine waste rocks, mine tailings, and smelting waste were studied by X-ray powder diffraction, polarized light microscopy, electron microprobe analysis, and digestion, leaching, and extraction procedures. The main Sb-bearing minerals and phases identified in the smelting waste were natrojarosite, iron (oxyhydr)oxides, mixtures of iron and antimony (oxyhydr)oxides, and tripuhyite; those in the mine tailings and mine waste rocks were iron (oxyhydr)oxides and/or mixtures of iron and antimony (oxyhydr)oxides. Iron (oxyhydr)oxides and natrojarosite had high Sb contents, with maximum values of 16.51 and 9.63 wt% Sb2O5, respectively. All three types of waste were characterized as toxic; the mine waste rocks and mine tailings would require pretreatment to decrease their leachable Sb content before they would be acceptable at hazardous waste landfills. Relatively little of the Sb was in desorbable forms, which accounted for <0.01 and <0.8% of the total Sb content in the smelting waste and mine waste rocks/mine tailings, respectively. Under reducing conditions, further Sb mobilization from mine waste rocks and mine tailings could occur (up to 4.6 and 3.3% of the total content, respectively), considerably increasing the risk that Sb will be introduced into the surroundings. Although the smelting waste had the highest total Sb content, it showed the lowest risk of Sb release under different environmental conditions. The significant Fe levels in the smelting waste facilitated the formation of various Fe compounds that greatly decreased the Sb mobilization from these wastes.
Asunto(s)
Antimonio , Minerales , Antimonio/análisis , Residuos Peligrosos , Hierro , ÓxidosRESUMEN
Military personnel with traveler's diarrhea (n=202) while deployed to Incirlik Air Base, Turkey, from June to September 2002 were evaluated for pathogen-specific immune responses. Serologic and fecal immunoglobulin A (IgA) titers to enterotoxigenic Escherichia coli antigens (CS6, CS3, and LT) were quite low. In contrast, subjects with Campylobacter infections had high serologic and fecal IgA responses.
Asunto(s)
Anticuerpos Antibacterianos/sangre , Infecciones por Campylobacter/inmunología , Campylobacter jejuni/inmunología , Disentería/inmunología , Escherichia coli Enterotoxigénica/inmunología , Infecciones por Escherichia coli/inmunología , Personal Militar , Antígenos Bacterianos/inmunología , Infecciones por Campylobacter/microbiología , Disentería/microbiología , Infecciones por Escherichia coli/microbiología , Heces/microbiología , Femenino , Humanos , Inmunoglobulina A/sangre , Inmunoglobulina G/sangre , Masculino , Viaje , TurquíaRESUMEN
The study of motor slowness based on observational methods has limitations. Whether motor retardation has a psychomotor or neuromotor basis is unclear because psychiatric and motor symptoms overlap. Observational methods lack the precision necessary to distinguish cognitive from motor processes. For the present study, we used an objective measure of neuromotor dysfunction to quantify the extent to which an individual programs movement velocity in anticipation of increasing target distance. Persons with Parkinson's disease (PD) or functional psychosis were studied with a group of healthy comparison subjects. Results indicated that the slope of the linear function relating velocity to distance was abnormal in the PD group and in approximately half of the psychosis group. Analyses revealed the measure to have high specificity and sensitivity. Weak correlations between velocity scaling and psychopathology support the neuromotor basis of the measure. We conclude that this measure of velocity scaling is relatively uninfluenced by cognitive factors that may underlie psychomotor retardation.
Asunto(s)
Discinesia Inducida por Medicamentos/fisiopatología , Enfermedad de Parkinson/fisiopatología , Trastornos Psicomotores/fisiopatología , Desempeño Psicomotor/fisiología , Trastornos Psicóticos/fisiopatología , Tiempo de Reacción/fisiología , Adulto , Anciano , Antipsicóticos/efectos adversos , Antipsicóticos/uso terapéutico , Discinesia Inducida por Medicamentos/diagnóstico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Unión Neuromuscular/efectos de los fármacos , Unión Neuromuscular/fisiopatología , Enfermedad de Parkinson/diagnóstico , Propiocepción/efectos de los fármacos , Propiocepción/fisiología , Trastornos Psicomotores/diagnóstico , Desempeño Psicomotor/efectos de los fármacos , Trastornos Psicóticos/diagnóstico , Trastornos Psicóticos/tratamiento farmacológico , Tiempo de Reacción/efectos de los fármacos , Sensibilidad y EspecificidadRESUMEN
The in vitro activities of 12 macrolide compounds against 28 Mycobacterium avium complex strains isolated from patients with acquired immunodeficiency syndrome were determined by the conventional proportion method and by the BACTEC method. Clarithromycin (A-56268; TE-031), a new macrolide compound, was the most active agent tested, inhibiting 90% of strains at an MIC of 4 micrograms/ml by the BACTEC method. Roxithromycin (RU 28965) and erythromycylamine inhibited 90% of strains at 16 micrograms/ml. The organisms showed high levels of resistance to most other macrolide compounds.
Asunto(s)
Antibacterianos/farmacología , Complejo Mycobacterium avium/efectos de los fármacos , Síndrome de Inmunodeficiencia Adquirida/complicaciones , Eritromicina/análogos & derivados , Eritromicina/farmacología , Humanos , Pruebas de Sensibilidad Microbiana , Infección por Mycobacterium avium-intracellulare/complicaciones , Infección por Mycobacterium avium-intracellulare/microbiologíaRESUMEN
The multiple-drug-resistance property of Mycobacterium avium complex (MAC) is mainly attributed to a cell envelope permeability barrier. MAC treated with subinhibitory levels of dimethyl sulfoxide (DMSO) and ethylenediaminetetraacetic acid (disodium salt) (EDTA) did not have altered minimum inhibitory concentration (MIC) levels or show ultrastructural changes; the effect of sodium dodecyl sulfate (SDS) was variable. With SDS, the visualization of the nucleoid and ribosomes decreased, and amorphous electron-dense material accumulated near the structurally altered cytoplasmic membrane and cell wall. Use of 0.005% Tween-80 resulted in a 2-4-fold reduction in MIC in the case of rifampicin, ansamycin (LM 427), cephapirin, and ciprofloxacin. Tween-80 treated cells were swollen, and deposits of low electron-density accumulated in the cytoplasm; distortions in the outer-cell integuments were observed. These findings are consistent with the idea that Tween-80 increases cell-envelope permeability, thereby enhancing drug penetrability and reducing MIC levels. Because of the action of Tween-80, its use in drug-susceptibility media or diluent fluids should be avoided.
Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/complicaciones , Complejo Mycobacterium avium/efectos de los fármacos , Tensoactivos/farmacología , Síndrome de Inmunodeficiencia Adquirida/microbiología , Antibacterianos/farmacología , Dimetilsulfóxido/farmacología , Sinergismo Farmacológico , Ácido Edético/farmacología , Humanos , Pruebas de Sensibilidad Microbiana , Complejo Mycobacterium avium/ultraestructura , Dodecil Sulfato de Sodio/farmacologíaRESUMEN
The properties of an unusual catalase isolated from Aspergillus niger are reported. The enzyme, which has a molecular weight of 323,000, consists of four subunits and is highly resistant to sodium azide.