Constructed wetlands for water quality improvements: Benefit transfer analysis from Ohio.

Water resources provide many benefits that generate value for residents and recreation users alike but run-off from agricultural and impervious surfaces can impair water quality, reducing any generated value. A possible solution to this problem is the construction of treatment wetlands to remove excessive nutrients from water bodies. This study uses environmental and economic data to approximate the costs of constructing and operating free surface water wetlands to remove phosphorus and estimates the amenity and recreational benefits of the resulting improvements in water quality for 24 lakes in Ohio. A ten percent improvement in water quality from a decrease in phosphorus loadings generates positive net benefits for all lakes in the sample with a lifetime cost benefit ratio of 2.92. The study also examines the potential use of constructed wetlands as the sole strategy to achieve a reduction goal for phosphorus loadings and find that the costs of doing so are prohibitive. Constructed wetlands can be a cost-effective component of a comprehensive strategy for small-scale nutrient reduction and water quality improvements for surface water bodies, but other treatment methods would be required to achieve any proposed targeted improvements.

Chronic exposure of HepG2 cells to excess copper results in depletion of glutathione and induction of metallothionein.

Metallothionein (MT) and reduced glutathione (GSH) play an important role in the intracellular handling of copper by preventing the generation and favouring the removal of copper-derived free radicals. The present study addressed the changes in MT and GSH that follow chronic (2 or 5 weeks) exposure of human hepatoblastoma cells (HepG2) to excess copper. Copper treatment (100 microM, 2 weeks) led to a 28-fold elevation in intracellular copper. Concomitantly, cells exhibited a seven-fold increase in total MT and an increment in its saturation with copper from 45 to 86%. Around 38% of copper in the cytosolic fraction could be accounted for by MT. GSH equivalents were substantially lowered (to 37% of basal levels) in treated cells, with only part of it being accounted for by an increase in GSSG. Copper-treatment induced no changes in catalase or GSH-peroxidase activities but it was associated with a small reduction in SOD (20%) and GSH-reductase (26%) activities. Copper-loaded cells did not differ from controls in their basal oxidative tone; however, when exposed to tert-butylhydroperoxide they exhibited a markedly greater susceptibility to undergo both oxidative stress and cell lysis. It is proposed that chronic exposure of HepG2 cells to excess copper is accompanied by "adaptive changes" in GSH and MT metabolism that would render cells substantially more susceptibility to undergo oxidative stress-related cytotoxicity.

Microsomal oxidative stress induced by NADPH is inhibited by nitrofurantoin redox biotranformation.

Nitrofurantoin is used in the antibacterial therapy of the urinary tract. This therapy is associated with various adverse effects whose mechanisms remain unclear. Diverse studies show that the nitro reductive metabolism of nitrofurantoin leads to ROS generation. This reaction can be catalyzed by several reductases, including the cytochrome P450 (CYP450) reductase. Oxidative stress arising from this nitro reductive metabolism has been proposed as the mechanism underlying the adverse effects associated with nitrofurantoin. There is, however, an apparent paradox between these findings and the ability of nitrofurantoin to inhibit lipid peroxidation provoked by NADPH in rat liver microsomes. This work was aimed to show the potential contribution of different enzymatic systems to the metabolism of this drug in rat liver microsomes. Our results show that microsomal lipid peroxidation promoted by NADPH is inhibited by nitrofurantoin in a concentration-dependent manner. This suggests that the consumption of NADPH in microsomes can be competitively promoted by lipid peroxidation and nitrofurantoin metabolism. The incubation of microsomes with NADPH and nitrofurantoin generated 1-aminohidantoin. In addition, the biotransformation of a classical substrate of CYP450 oxidative system was competitively inhibited by nitrofurantoin. These results suggest that nitrofurantoin is metabolized through CYP450 system. Data are discussed in terms of the in vitro redox metabolism of nitrofurantoin.

Sulfhydryl oxidation overrides Mg(2+) inhibition of calcium-induced calcium release in skeletal muscle triads.

We studied the effect of oxidation of sulfhydryl (SH) residues on the inhibition by Mg(2+) of calcium-induced calcium release (CICR) in triad-enriched sarcoplasmic reticulum vesicles isolated from rabbit skeletal muscle. Vesicles were either passively or actively loaded with calcium before eliciting CICR by dilution at pCa 4.6-4.4 in the presence of 1.2 mM free [ATP] and variable free [Mg(2+)]. Native triads exhibited a significant inhibition of CICR by Mg(2+), with a K(0.5) approximately 50 microM. Partial oxidation of vesicles with thimerosal produced a significant increase of release rate constants and initial release rates at all [Mg(2+)] tested (up to 1 mM), and shifted the K(0.5) value for Mg(2+) inhibition to 101 or 137 microM in triads actively or passively loaded with calcium, respectively. Further oxidation of vesicles with thimerosal completely suppressed the inhibitory effect of [Mg(2+)] on CICR, yielding initial rates of CICR of 2 micromol/(mg x s) in the presence of 1 mM free [Mg(2+)]. These effects of oxidation on CICR were fully reversed by SH reducing agents. We propose that oxidation of calcium release channels, by decreasing markedly the affinity of the channel inhibitory site for Mg(2+), makes CICR possible in skeletal muscle.

Estudio multicéntrico con roxitromicina en dosis única / Multicentric study of single dose administration of roxithromycin

Roxitromicina es un nuevo macrólido semisintético derivado de la eritromicina. A, que presenta mayor estabilidad frente al medio ácido, mayor biodisponibilidad, con niveles de concentración sanguíneos y tisulares más elevados y una vida media prolongada que permite administrarlo cada 24 h. Se efectuó un estudio multicéntrico, abierto y no comparativo con médicos de 6 ciudades de Chile, en que el objetivo fue evaluar la eficacia y la tolerancia clínica de la roxitromicina en una sola dosis diaria de 300 mg en el tratamiento de infecciones respiratorias altas (10 días) y bajas (10-14 días). Se estudiaron 151 episodios de 144 pacientes, 60 varones y 91 mujeres, con un promedio de edad de 38 años y seis meses (9-98 años). 60,9 por ciento de las infecciones fueron altas y 29,1 por ciento bajas. La eficacia fue considerada excelente en el 52,6 por ciento de los casos, buena en el 36,3 por ciento, moderada en el 7,8 por ciento y mala en el 3,4 por ciento. Se presentaron reacciones adversas en 9 episodios (6 por ciento), siendo éstas fundamentalmente manifestaciones gastrointestinales. Solo en dos pacientes fue necesaria la suspensión de la terapia (1,3 por ciento). Los resultados son considerados ampliamente satisfactorios y comparables a otras experiencias

Efecto del climaterio en la calidad de vida / Effect of the climaterium in the quality of life

Evaluar el efecto del climaterio en la calidad de vida (CV). Pacientes y método: con el cuestionario específico de calidad de vida para la menopausia (Universidad de Toronto) estudiamos a 481 mujeres entre 40 y 59 años. Resultados. Las mujeres peri o postmenopáusicas tienen puntajes más altos o sea, peor CV que las mujeres con ciclos normales en las cuatro áreas del cuestionario; así, tienen un riesgo (OR) 9,3 veces mayor de tener molestias vasomotoras que alteren la CV (IC: 3,5-26,8, p < 0,0001), 3,8 veces mayor riesgo de deterioro psicosocial (IC: 1,8-8,4; p < 0,0001), 8,0 veces mayor riesgo de trastornos físicos (IC: 3,0-23,3, p < 0,0001) y 5,4 de alteraciones de la sexualidad (IC: 2,2-14,3, p < 0,0001). La edad no modificó significativamente los puntajes de CV tanto en mujeres pre como postmenopáusicas. Conclusión: el climaterio produce pérdida de la calidad de vida, la cual es independiente de la edad

Patrones de conducta sexual en mujeres chilenas / Sexual behavior patterns in chilean women

Background: Sexuality has an individual connotation, is influenced by biological, environmental and cultural factors and is present throughout all life. Aim: To assess the sexual behavior of a group of Chilean women. Subjects and methods: A specially devised inquiry was applied to 301 women, aged 20 to 70 years old, that consulted in a medical service. Results: Seventy seven percent of women are sexually active. These figures ranged from 80 percent of women aged 40-44 years old to 40 percent of women over 60. Sixty percent of women living together, 53.7 percent of single women, 65.6 percent of divorced women. 94.2 percent of married women and 100 percent of widows were sexually active. Women aged 25 to 29 years old had a mean of 8.4 relations per month compared with 3.3 relations among women older than 55. The frequency of sexual intercourse was higher in women living together and lower in widows. The mean age at the first intercourse was 20.6 ± 4.5 years. Ninety three percent had experienced sexual desire and the percentage of satisfactory sexual relations does not change with age. Less educated women had a lower frequency of orgasms. Conclusions: Age and legal status of women are related lo their sexual behavior and less educated women have a less satisfactory sexual life