Clinical and analytical toxicology of dietary supplements: a case study and a review of the literature.
ABSTRACT The use of dietary supplements has grown dramatically in the last decade. A large number of dietary and herbal supplements escape regulatory and quality control; components of these preparations are poisonous and may contain, among other toxins, heavy metals. Uncontrolled use of dietary and herbal supplements by special populations, such as the military, may therefore pose a health risk. Clinical symptoms are not always properly attributed to dietary supplements; patients often do not mention supplement use to their health care provider. Therefore, a health risk estimate is hard to make on either the individual or the population level. The literature on this issue was reviewed and discussed in the light of a representative clinical-chemical case study. This case study was performed on a host of preparations that were used by one single individual in the military. Both essential (chromium, copper, zinc, and iron) and poisonous (arsenic, lead, and nickel) trace elements were determined using inductively coupled plasma combined with optical emission spectrometry (ICP-OES) or with mass spectrometry (ICP-MS). Arsenic and lead were detected at exposure levels associated with health risks. These health risks were detected predominantly in hormone-containing supplements and the herbs and botanicals used for performance enhancement. To the extent that this is a representative sample, there is an underestimation of supplement use and supplement risk in the US military, if not in the general population. Since clinical symptoms may be attributed to other causes and, unless patients are specifically asked, health care providers may not be aware of their patients' use of dietary supplements, a strong support of laboratory diagnostics, such as a toxicological screening of blood or urine, is required. In addition, screening of the preparations themselves may be advised.
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ABSTRACT: Single crystals of 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 were directionally solidified from the melt exposed to 7atm air pressure (7atm). The X-ray studies show that the obtained crystals have rhombohedral or tetragonal structure depending on the composition. In contrast to the experiments conducted at atmospheric pressure, the experiments conducted under 7atm of air yielded transparent light-yellow crystals, free of pyrochlore phase. The temperature and frequency dependence of the dielectric constant and dielectric loss demonstrate a relaxor ferroelectric behavior. The room temperature dielectric constant ε measured on unpoled (001) oriented specimens is 8200, demonstrating high crystalline perfection.Journal of Crystal Growth 01/2005; 274(1):118-125. · 1.69 Impact Factor
- Food and Chemical Toxicology - FOOD CHEM TOXICOL. 01/2007; 6(7):18-18.
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ABSTRACT: Metal translocation to the brain is strictly controlled and often prevented by the blood-brain barrier. For the most part, only those metals required to maintain normal function are transported into the brain where they are under tight metabolic control. From the literature, there are reports that traumatic brain injury disrupts the blood-brain barrier. This could allow the influx of metals that would normally have been excluded from the brain. We also have preliminary data showing that metal pellets, surgically-implanted into the leg muscle of a rat to simulate a shrapnel wound, solubilize and the metals comprising the pellet can enter the brain. Surprisingly, rats implanted with a military-grade tungsten alloy composed of tungsten, nickel, and cobalt also showed significantly elevated uranium levels in their brains as early as 1month after pellet implantation. The only source of uranium was low levels that are naturally found in food and water. Conversely, rats implanted with depleted uranium pellets demonstrated elevated uranium levels in brain resulting from degradation of the implanted pellets. However, when cobalt levels were measured, there were no significant increases in the brain until the rats had reached old age. The only source of cobalt for these rats was the low levels found in their food and water. These data suggest that some metals or metal mixtures (i.e., tungsten alloy), when embedded into muscle, can enhance the translocation of other, endogenous metals (e.g., uranium) across the blood-brain barrier. For other embedded metals (i.e., depleted uranium), this effect is not observed until the animal is of advanced age. This raises the possibility that metal body-burdens can affect blood-brain barrier permeability in a metal-specific and age-dependent manner. This possibility is disconcerting when traumatic brain injury is considered. Traumatic brain injury has been called the "signature" wound of the conflicts in Iraq and Afghanistan, often, an embedded metal fragment wound occurs simultaneously. Since the blood-brain barrier can be disrupted by traumatic brain injury, this raises the possibility of free access to the brain for any metals found in the body. Therefore, we hypothesize that this influx of metals overwhelms normal brain homeostasis, depletes the brain's antioxidant defense systems, and activates microglial cells resulting in the release of inflammatory mediators that can potentially exacerbate the adverse effects of traumatic brain injury.Medical Hypotheses 02/2014; · 1.15 Impact Factor