Heavy metals are naturally occurring elements that have a high atomic weight and a density at least five times greater than that of water. Their multiple industrial, domestic, agricultural, medical, and technological applications have led to their wide distribution in the environment, raising concerns over their potential effects on human health and the environment. Their toxicity depends on several factors including the dose, route of exposure, and chemical species, as well as the age, gender, genetics, and nutritional status of exposed individuals. Because of their high degree of toxicity, arsenic, cadmium, chromium, lead, and mercury rank among the priority metals that are of public health significance. These metallic elements are considered systemic toxicants that are known to induce multiple organ damage, even at lower levels of exposure. They are also classified as human carcinogens (known or probable) according to the US Environmental Protection Agency and the International Agency for Research on Cancer. This review provides an analysis of their environmental occurrence, production and use, potential for human exposure, and molecular mechanisms of toxicity, genotoxicity, and carcinogenicity.

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Heavy metal toxicity and the environment.

Interpretation of clinical trials comparing different drug regimens for Parkinson's disease (PD) is complicated by the different dose intensities used: higher doses of levodopa and, possibly, other drugs produce better symptomatic control but more late complications. To address this problem, conversion factors have been calculated for antiparkinsonian drugs that yield a total daily levodopa equivalent dose (LED). LED estimates vary, so we undertook a systematic review of studies reporting LEDs to provide standardized formulae. Electronic database and hand searching of references identified 56 primary reports of LED estimates. Data were extracted and the mean and modal LEDs calculated. This yielded a standardized LED for each drug, providing a useful tool to express dose intensity of different antiparkinsonian drug regimens on a single scale. Using these conversion formulae to report LEDs would improve the consistency of reporting and assist the interpretation of clinical trials comparing different PD medications.

Systematic review of levodopa dose equivalency reporting in Parkinson's disease

BACKGROUND Semen quality is taken as a surrogate measure of male fecundity in clinical andrology, male fertility, reproductive toxicology, epidemiology and pregnancy risk assessments. Reference intervals for values of semen parameters from a fertile population could provide data from which prognosis of fertility or diagnosis of infertility can be extrapolated. METHODS Semen samples from over 4500 men in 14 countries on four continents were obtained from retrospective and prospective analyses on fertile men, men of unknown fertility status and men selected as normozoospermic. Men whose partners had a time-to-pregnancy (TTP) of < or =12 months were chosen as individuals to provide reference distributions for semen parameters. Distributions were also generated for a population assumed to represent the general population. RESULTS The following one-sided lower reference limits, the fifth centiles (with 95th percent confidence intervals), were generated from men whose partners had TTP < or = 12 months: semen volume, 1.5 ml (1.4-1.7); total sperm number, 39 million per ejaculate (33-46); sperm concentration, 15 million per ml (12-16); vitality, 58% live (55-63); progressive motility, 32% (31-34); total (progressive + non-progressive) motility, 40% (38-42); morphologically normal forms, 4.0% (3.0-4.0). Semen quality of the reference population was superior to that of the men from the general population and normozoospermic men. CONCLUSIONS The data represent sound reference distributions of semen characteristics of fertile men in a number of countries. They provide an appropriate tool in conjunction with clinical data to evaluate a patient's semen quality and prospects for fertility.

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World Health Organization reference values for human semen characteristics

Differently from passive Brownian particles, active particles, also known as self-propelled Brownian particles or microswimmers and nanoswimmers, are capable of taking up energy from their environment and converting it into directed motion. Because of this constant flow of energy, their behavior can be explained and understood only within the framework of nonequilibrium physics. In the biological realm, many cells perform directed motion, for example, as a way to browse for nutrients or to avoid toxins. Inspired by these motile microorganisms, researchers have been developing artificial particles that feature similar swimming behaviors based on different mechanisms. These man-made micromachines and nanomachines hold a great potential as autonomous agents for health care, sustainability, and security applications. With a focus on the basic physical features of the interactions of self-propelled Brownian particles with a crowded and complex environment, this comprehensive review will provide a guided tour through its basic principles, the development of artificial self-propelling microparticles and nanoparticles, and their application to the study of nonequilibrium phenomena, as well as the open challenges that the field is currently facing.

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Active Particles in Complex and Crowded Environments

9.2. Protein-Based Hg(II) Detectors 3467 9.3. Oligonucleotide-Based Hg(II) Detector 3467 9.4. DNAzyme-Based Hg(II) Detectors 3469 9.5. Antibody-Based Hg(II) Detector 3469 10. Mercury Detectors Based on Materials 3469 10.1. Soluble and Fluorescent Polymers 3469 10.2. Membranes, Films, and Fibers 3471 10.3. Micelles 3473 10.4. Nanoparticles 3473 11. Perspectives 3474 12. Addendum 3475 12.1. Small Molecules 3475 12.2. Biomolecules 3477 12.3. Materials 3477 13. List of Abbreviations 3477 14. Acknowledgments 3478 15. References 3478

Tools and tactics for the optical detection of mercuric ion.

Exposure to Well-Water Arsenic and Manganese and Intellectual Function in Children in Araihazar, Bangladesh

Stress and Salivary Telomere Length in the Second Half of Life: A Comparison of Life-course Models.

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Socioeconomic Status, Occupational Characteristics, and Semen Quality in Fertile Men

Background Essential tremor (ET) is among the most common neurological diseases and it often runs in families. How knowledgeable ET patients and their families are about their disease has been the subject of surprisingly little scholarship. Methods To fill this gap in knowledge, we administered a comprehensive 32-item survey (i.e., questions about etiology, pathophysiology, symptoms and signs, natural history and treatments) to 427 participants, including 76 ET probands, 74 affected relatives [AFRs], 238 unaffected relatives, and 39 spouses of unaffected relatives, all of whom were participating in two ET family studies. We hypothesized that there would be gaps in knowledge about ET and furthermore, that probands and AFRs would be the most knowledgeable, followed by unaffected relatives and then spouses of unaffected relatives, who would be the least knowledgeable. Results Overall, ET patients lacked knowledge about their disease. Nearly 1/3 of probands answered “yes” or “do not know” to the question, “is ET the same or different from the type of tremor that many normal people can get when they become old and frail?” A similar proportion did not know whether children could get ET or they responded “no”. Nearly 1/4 of affecteds (i.e., probands and AFRs) did not know whether or to what degree (e.g., very well, moderately well, not well) the symptoms of ET could be medically controlled, and 38.0% either reported that there was no brain surgery for ET or reported that they did not know. Nearly 17% of affecteds did not endorse genes as a cause for ET, which was surprising given the fact that this was a family study of ET. Probands and AFRs were the most knowledgeable, followed by unaffected relatives. Spouses of unaffected relatives were the least knowledgeable. Conclusion We targeted a large group of ET patients and their families, as this group is perhaps most likely to be informed about the disease. ET patients and their affected relatives were more knowledgeable about the features of ET than their family members without ET. Overall, however, knowledge of ET was very limited and this lack of knowledge encompassed all aspects of the disease including

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Pam Factor-Litvak

Papers

Exposure to Well-Water Arsenic and Manganese and Intellectual Function in Children in Araihazar, Bangladesh

Stress and Salivary Telomere Length in the Second Half of Life: A Comparison of Life-course Models.

Socioeconomic Status, Occupational Characteristics, and Semen Quality in Fertile Men

Knowledge about Essential Tremor: A Study of Essential Tremor Families.

More unaffected first-degree relatives of essential tremor cases have mild cognitive deficits than age-matched controls.