Reproductive dysfunction in women with epilepsy: antiepileptic drug effects on sex-steroid hormones.

Women with epilepsy are at risk for reproductive health dysfunction. Sex-steroid hormone abnormalities have been reported in women with epilepsy, but it has been difficult to determine whether these abnormalities are due to epilepsy-related hypothalamic-pituitary axis dysfunction, or to pharmacokinetic actions of antiepileptic drugs (AEDs). Sex-steroid hormones were evaluated in 84 reproductive-aged women with epilepsy receiving an AED in monotherapy, and in 20 nonepileptic controls. Estrone, free testosterone, and androstenedione were significantly lower in subjects receiving enzyme-inducing AEDs than in nonepileptic controls. Free testosterone was significantly elevated in subjects receiving valproate compared to nonepileptic controls. Subjects with epilepsy receiving gabapentin or lamotrigine were no different from the nonepileptic controls in any of the endocrine variables. Subjects with epilepsy who are receiving AEDs that alter cytochrome P450 enzymes are at risk for significant abnormalities in sex-steroid hormones. In contrast, subjects receiving AEDs that do not alter cytochrome P450 enzymes show no differences in sex-steroid hormones compared with nonepileptic controls. With new AEDs available that do not alter cytochrome P450 enzymes, physician selection of therapy should consider not only seizure control, but also potential effects on reproductive physiology.

Biogeochemical removal of Zn and Cd in the Coeur D'Alene River (Idaho, USA), downstream of a mining district.

The conservative biogeochemical behavior of dissolved Zn and Cd in a 17-km, free-flowing reach of the Coeur d'Alene River downstream of a mining district is typical of watersheds in which suspended matter concentrations are low. For watersheds impacted by acid-rock drainage (ARD), low suspended matter concentrations are more likely to be found when acid rock drainage travels through soils because much of the Fe and Al that could form adsorbing surfaces is retained within the soils. In the absence of additional sources of solid substrates, metals can be transported great distances downstream once this Fe- and Al-poor ARD seeps into surface waters. In a 46-km backwater reach of the Coeur d'Alene River, it appears that biological activity increased pH and provided the organic matter solid substrate which removed approximately 50% of the Zn and Cd. Zn removal was partially reversible as pH decreased. These observations reinforce the concept that both inorganic and organic carbon chemistry must be measured if significant. advances in our understanding of the attenuation of Zn and Cd from ARD sources are to be made.

Separate dissolved and particulate trace metal budgets for an estuarine system: an aid for management decisions.

The sources and sinks of dissolved and particulate Pb, Cu and Zn were determined for the main basin of Puget Sound to understand the effect man has had on metal concentrations in both the water column and in the sediments. Municipal, industrial and atmospheric sources contributed about 66% of the total Pb added to the main basin of Puget Sound during the early 1980s. Advective inputs were the major sources of total Cu and Zn (approximately 40%) while riverine and erosional sources contributed about 30%. The discharge of the particle-bound trace metals from rivers minimized the influence of particulate anthropogenic sources, which constituted 50%, 23% and 18% of the total particulate Pb, Cu and Zn inputs, respectively. While advective transport was the major source of dissolved Cu and Zn (approximately 60% of all dissolved inputs), industrial, municipal and atmospheric inputs contributed about 85%, 30% and 38% of the dissolved Pb, Cu and Zn inputs, respectively. The sources of dissolved and particulate Cu and Zn were comparable with the sinks within the errors of the analyses indicating their quasi-conservative nature. Advection removed about 60% of the total Cu and Zn added to the main basin while 40% was deposited in the sediments of Puget Sound. Because of this quasi-conservative nature of Cu and Zn, anthropogenic inputs of Cu and Zn were dispersed from the system more than they were contained within main basin sediments. About 75% of the dissolved Pb discharged into the main basin of Puget Sound was lost from the dissolved phase and was balanced by a similar gain in the particulate phase. Because of this extensive scavenging and the effective retention of particles within the main basin, about 70% of the total Pb added to the main basin was retained within its sediments. These separate mass balances have utility in management decisions because they show the relative contributions from different sources and demonstrate whether the influences of dissolved and particulate inputs are reflected solely in the water column or the sediments, respectively.

Partitioning of copper at concentrations below the marine water quality criteria.

Partitioning of Cu between the aqueous and particulate phases and among their components was examined in six ambient Puget Sound, Washington State, USA, samples (6-10 nM Cu). Most of the particulate Cu (4-12% of the total Cu) was associated with particulate organic matter, and resulted in distribution coefficients (Kd) ranging between 10(4.55) and 10(5.1). For the dissolved phase, the portion of Cu extracted by C18-packed cartridges averaged 44% (+11%). Radioactive 64Cu was added to these samples to total stable Cu concentrations (17-33 nM). After 24 h of equilibration, the portion of 64Cu associated with the particulate matter in five of the six samples (Kd between 10(4.7) and 10(5.3) was an average of 70% higher than that of natural Cu in the ambient samples. In contrast, only 19 +/- 7% of the 64Cu was extracted by C18-packed cartridges. The partitioning of natural Cu and 64Cu onto particles was not significantly different when the equilibria were based on dissolved Cu passing through the C18 cartridges. Further research is warranted on utilizing the hydrophilic component of the dissolved phase as a parameter on which water quality criteria are based.

Analysis of biogenic carbonates by inductively coupled plasma-mass spectrometry (ICP-MS). Flow injection on-line solid-phase preconcentration for trace element determination in fish otoliths.

The aragonite deposits within the ear bones (otoliths) of teleost fish retain a chemical signal reflecting the life history of fish (similar to rings of trees) and the nature of fish habitats. Otoliths dissolved in acid solutions contain high concentrations of calcium and a variety of proteins. Elimination of matrix salts and organic interferences during preconcentration is essential for accurate determination of trace elements in otolith solutions by inductively coupled plasma-quadrupole mass spectrometry. An iminodiacetate-based chelating resin (Toyopearl AF-Chelate 650 M) has been used for on-line preconcentration and matrix separation for the determination of 31 transition and rare elements. Successful preconcentration of the elements was achieved at pH 5 by on-line buffering, except Mn which required pH 8.8. Sample solutions were loaded on to the column for 1 min at 3.2 mL min(-1), and then eluted directly into the mass spectrometer with 4% v/v nitric acid. This procedure enabled up to 25-fold preconcentration with successful removal of the calcium matrix. The effect of heat-assisted oxidation with concentrated nitric acid was investigated to eliminate the organic matrix. It was found that heating to dryness after dissolution and further mineralization with the acid significantly improved the retention of the transition elements. The method was validated by analysis of a certified reference material produced from saggittal otoliths of emperor snapper ( Lutjanus sebae), and then applied to the determination of trace metal concentrations in juvenile bluefin tuna ( Thunnus thynnus) from the Western Pacific Ocean.