RESUMEN
Agriculture is a major nonpoint source of phosphorus (P) in the Midwest, but how surface runoff and tile drainage interact to affect temporal concentrations and fluxes of both dissolved and particulate P remains unclear. Our objective was to determine the dominant form of P in streams (dissolved or particulate) and identify the mode of transport of this P from fields to streams in tile-drained agricultural watersheds. We measured dissolved reactive P (DRP) and total P (TP) concentrations and loads in stream and tile water in the upper reaches of three watersheds in east-central Illinois (Embarras River, Lake Fork of the Kaskaskia River, and Big Ditch of the Sangamon River). For all 16 water year by watershed combinations examined, annual flow-weighted mean TP concentrations were >0.1 mg L(-1), and seven water year by watershed combinations exceeded 0.2 mg L(-1). Concentrations of DRP and particulate P (PP) increased with stream discharge; however, particulate P was the dominant form during overland runoff events, which greatly affected annual TP loads. Concentrations of DRP and PP in tiles increased with discharge, indicating tiles were a source of P to streams. Across watersheds, the greatest DRP concentrations (as high as 1.25 mg L(-1)) were associated with a precipitation event that followed widespread application of P fertilizer on frozen soils. Although eliminating this practice would reduce the potential for overland runoff of P, soil erosion and tile drainage would continue to be important transport pathways of P to streams in east-central Illinois.
Asunto(s)
Agricultura/métodos , Fósforo/análisis , Movimientos del Agua , Contaminantes Químicos del Agua/análisis , Lluvia , Ríos/química , Nieve , Abastecimiento de AguaRESUMEN
Chronic inhalation of hard metal (WC-Co) particles causes alveolitis and the eventual development of pulmonary fibrosis. The initial inflammatory response includes a change in the alveolar epithelial cell-capillary barrier, which has been shown to be regulated by the state of assembly and organization of the actin cytoskeletal network. The objective of this study was to evaluate the effect WC-Co particles have on F-actin organization of lung epithelial cells in an in vitro culture system. Rat lung epithelial (L2) cells were exposed to 5, 25, and 100 microg/mL of WC-Co particles, as well as the individual components (Co and WC) of the hard metal mixture particles for 24 h. The effect on F-actin organization was visualized by laser scanning confocal microscopy (LSCM) following Bodipy-Phallacidin staining. Minimal changes in the F-actin microfilaments of L2 cells were observed by LSCM after exposure to WC and WC-Co at 5 and 25 microg/mL, while at 100 microg/mL, there was a noticeable disruption in the uniform distribution of L2 cell F-actin microfilaments. After exposure to Co, a dose-dependent change in the F-actin organization of the L2 cells was observed. Little change in F-actin assembly was observed after treatment with 5 microg/mL of Co (the concentration equivalent to the 5% amount of Co commonly present in 100 microg/mL of the WC-Co sample mixture). However, at 100 microg/mL of Co, the microfilaments aggregated into homogeneous masses within the cells, and a significant loss in the organization of L2 F-actin was observed. These dramatic alterations in F-actin organization seen after exposure to the higher doses of Co were attributed to an increase in L2 cell injury as measured by lactate dehydrogenase and trypan blue exclusion. We conclude the pulmonary response evoked in the lung by inhalation of high levels of WC-Co particles is unlikely due to alterations in the F-actin microfilaments of lung-epithelial cells.
Asunto(s)
Actinas/metabolismo , Citoesqueleto/efectos de los fármacos , Células Epiteliales/efectos de los fármacos , Exposición por Inhalación/efectos adversos , Pulmón/efectos de los fármacos , Metales Pesados/toxicidad , Citoesqueleto de Actina/efectos de los fármacos , Aleaciones/administración & dosificación , Aleaciones/toxicidad , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Cobalto/administración & dosificación , Cobalto/toxicidad , Citoesqueleto/metabolismo , Citoesqueleto/patología , Relación Dosis-Respuesta a Droga , Células Epiteliales/metabolismo , Células Epiteliales/patología , Colorantes Fluorescentes , L-Lactato Deshidrogenasa/metabolismo , Pulmón/metabolismo , Pulmón/patología , Metales Pesados/administración & dosificación , Microscopía Confocal , Microscopía de Contraste de Fase , Fibrosis Pulmonar/inducido químicamente , Fibrosis Pulmonar/patología , Ratas , Compuestos de Tungsteno/administración & dosificación , Compuestos de Tungsteno/toxicidadRESUMEN
Chaparral is considered to act as an antioxidant. However, the inhibitory effects of chaparral on specific radical species are not well understood. Using electron paramagnetic resonance (EPR) spectroscopy in combination with spin trapping techniques, we have found that chaparral scavenges superoxide anion radical (O2*-) in a dose-dependent manner. 5,5-dimethyl-lpyrroline-N-oxide (DMPO) was used as a spin trapping agent and the reaction of xanthine and xanthine oxidase as a source of O2*-. The kinetic parameters, IC50 and Vmax, for chaparral scavenging of O2*- were found to be 0.899 microg/mL and 8.4 ng/mL/sec, respectively. The rate constant for chaparral scavenging O2*- was found to be 1.22 x 10(6) g(-1) s(-1). Our studies suggest that the antioxidant properties of chaparral may involve a direct scavenging effect of the primary oxygen radical, O2*-.
Asunto(s)
Extractos Vegetales/metabolismo , Plantas Medicinales , Superóxidos/metabolismo , Espectroscopía de Resonancia por Spin del Electrón , Depuradores de Radicales Libres , Cinética , Hojas de la Planta/químicaRESUMEN
The carbamate 1-(methyl-3-(N,N-dimethylcarbamoyloxy)-2-pyridylmethylene)-4 -(4-phenyl) diazinecarboxamide chloride (MHP 133) is the parent for a new class of pyridinium salts which inhibit acetylcholinesterase (AChE) in vitro as well as in vivo. Fourteen new derivatives of MHP 133 have been synthesized with the intention of improving their hydrophobicity while maintaining their propensity to inhibit acetylcholinesterase. Upon prolonged incubation with AChE, the pyridinium salts exhibit progressive time-dependent inhibition according to first order kinetics with kobs/[I] values ranging from 3 to 345 M-1s-1. The enzyme did not regain any activity after prolonged incubation with the inhibitors (1 day). The partition coefficients for each inhibitor were evaluated in octanol/water in order to determine their hydrophobic character as hydrophobicity is a key prerequisite for crossing the blood brain barrier.
Asunto(s)
Inhibidores de la Colinesterasa/síntesis química , Compuestos de Piridinio/síntesis química , Acetiltiocolina/metabolismo , Animales , Carbamatos/síntesis química , Carbamatos/farmacología , Inhibidores de la Colinesterasa/farmacología , Anguilas , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Imidas/síntesis química , Imidas/farmacología , Cinética , Espectroscopía de Resonancia Magnética , Modelos Químicos , Estructura Molecular , Compuestos de Piridinio/farmacologíaRESUMEN
Inferior vena cava thrombosis is an uncommon but potentially serious complication of caval filter placement. A 34-year-old man with symptomatic caval thrombosis, which occurred 6 weeks after filter placement, was successfully treated with a combination of pulse-spray and local infusion of urokinase.