Environmental impacts and metal exposure of aquatic ecosystems in rivers contaminated by small scale gold mining: the Puyango River basin, southern Ecuador.

Gold mining in the Portovelo-Zaruma district in southern Ecuador is causing considerable environmental impacts; the most important ones are related to the discharge of cyanide, mercury and metal rich tailings into rivers of the Puyango catchment area. Cyanide and metal levels in rivers regularly exceed environmental quality criteria. The contamination impacts biodiversity, with cyanide causing a direct lethal effect on biota close to source and metal contaminants considerably reducing aquatic biodiversity further downstream. It is shown that the prevailing neutral or slightly alkaline conditions of the rivers ensure that metals are mainly associated with sediment. However, elevated metal levels in bottom living larvae collected from contaminated sites suggest that these sediment bound metals are readily bioavailable. Leaching experiments indicate that the relative ease by which metals are taken up by larvae is related to the speciation of sediment associated metals. It is further shown that large amounts of metals, which are bound to suspended sediment under ambient pH conditions, enter the dissolved and directly bioavailable state in more acidic conditions. Metal levels in carnivorous fish were found to be modestly elevated only, with the exception of mercury. Mercury levels exceeded 0.5 mg/kg in fish from both contaminated and uncontaminated sites, showing that both methylation and bioaccumulation of mercury are occurring in the Puyango river basin.

Veiled, voluminous, and devalued: narrative stories about low-income women from Brazil, Egypt, and Colombia.

The first purpose of this article is to argue the significance of using international and culturally diverse exemplars in developing nursing knowledge. The second is to identify some urgent priorities in the development of nursing knowledge, particularly as related to women's health. The lived experiences of three women from Brazil, Egypt, and Colombia who are in low-income, devalued, but important jobs are presented through their voices. These storied accounts highlight nursing's mission in dealing with the marginalized client as a human being whose context is historical and sociocultural. The implications for knowledge development as driven by international exemplars, diverse experiences, and narration of stories are discussed.

Immunoblotting of plasma in a pregnant patient with hereditary angioedema.

Hereditary angioedema (HAE), an autosomal disorder caused by a deficiency of C1 inhibitor, is characterized by attacks of localized swelling, laryngeal edema, or abdominal pain. Plasma samples from one pregnant patient were studied serially by functional and quantitative immunochemical assays as well as immunoblot assays for high molecular weight kininogen (HMWK) and/or prekallikrein/kallikrein (PK/K). An immunoblot of this patient's HMWK from plasma obtained before she became pregnant and when she was well revealed that it was mostly an intact protein of 120 kd, similar to immunoblot results of normal plasma HMWK. In plasma samples taken throughout her pregnancy, before, during, and after clinical attacks of angioedema, all of her plasma HMWK was shown to be cleaved into the 45 kd light chain form. After delivery of the infant the 120 kd form of intact plasma HMWK returned to her plasma. In comparison, immunoblot studies on 21 normal and abnormal pregnancies revealed that plasma HMWK was an intact protein at 120 kd. That this patient's plasma during her pregnancy was contact activated was determined by additional immunoblot studies for PK/K. Immunoblot assay for plasma PK/K revealed kallikrein-alpha 2-macroglobulin complexes and a 50 kd PK/K form seen only in activated plasma samples. The findings of kallikrein-alpha 2-macroglobulin complexes and a 50 kd PK/K form disappeared after delivery. These combined studies on this patient show that the structures of HMWK and prekallikrein as indicated by immunoblot assays were altered during pregnancy. Immunoblot assays for detection of changes in the structure of HMWK and prekallikrein may be objective laboratory studies for documenting clinical attacks of hereditary angioedema, their onset, and their resolution.

A clinical and pathologic study of chronic sinusitis: the role of the eosinophil.

Evidence exists that the eosinophil plays an important role in mediating injury to bronchial epithelium in chronic asthma. Here, the role of the eosinophil in chronic inflammatory disease of the paranasal sinuses was studied with tissue from patients who underwent surgery for chronic sinusitis. Paranasal tissue from patients with chronic asthma and/or allergic rhinitis was extensively infiltrated with eosinophils. Immunofluorescent studies demonstrated a striking association between the presence of extracellular deposition of major basic protein and damage to sinus mucosa. The histopathology of paranasal respiratory epithelium appeared similar to that described in bronchial asthma. These findings suggest that the eosinophil acts as an effector cell in chronic inflammatory disease of paranasal respiratory epithelium. Thus, sinus disease in patients with asthma may be due to the same mechanisms that cause damage to bronchial epithelium.