On the possibility of creating a magnetic field with a given degree of spatial inhomogeneity.

Proposed here is a method for constructing systems of circular thin Helmholtz coils (conic coils), which makes it possible to obtain a magnetic field with any degree of inhomogeneity by doubling the number of coils. A functional relationship is obtained between the currents of the coils and their distances to the center, which allows zeroing all derivatives in the expansion of the magnetic field in a series in spatial variables in the center of the system to a derivative of arbitrary order. An analytical expression is obtained for the magnitude of the magnetic field of the systems along the axis of symmetry. All the systems considered here have the same parity (oddness) of the projections of the magnetic field with respect to spatial variables and equal inhomogeneity in all directions in the center of symmetry.

External beam radiation therapy (EBRT) for patients with malignant pheochromocytoma and non-head and -neck paraganglioma: combination with 131I-MIBG.

In patients with malignant pheochromocytoma and paraganglioma, 131I-MIBG radiotherapy can achieve an objective response rate of 30-50% with the dose limiting toxicity being hematologic. Patients with disseminated disease, who also have a few index bulky or symptomatic lesions, may benefit from the addition of targeted external beam radiotherapy alone or in combination with systemic 131I-MIBG. The records of patients with malignant paraganglioma who were treated with external beam radiotherapy at the University of Pennsylvania from February 1973 to February 2011 were reviewed in an institutional review board approved retrospective study. Of the 17 patients with tumors in the thorax, abdomen, or pelvis, 76% had local control or clinically significant symptomatic relief for at least 1 year or until death. As expected, the predominant toxicity was due to irradiation of tumor-adjacent normal tissues without clinically significant hematologic toxicity. Due to widespread systemic metastases with areas of bulky, symptomatic tumor, 5 of the 17 patients were treated with sequential 131I-MIBG (2 mCi/kg per treatment) and external beam radiotherapy to 9 sites. In these patients, all areas that were irradiated with external beam radiotherapy showed durable objective response despite all patients eventually experiencing out-of-field systemic progression requiring other treatment. Four of these patients remain alive with excellent performance status 16, 18, 23, and 24 months after external beam radiotherapy. External beam radiotherapy can be highly effective in local management of malignant paraganglioma and can be used in conjunction with 131I-MIBG due to nonoverlapping toxicities with excellent control of locally bulky tumors.

General scientific principles of chemical safety - IPCS Training Module no. 4

It presents information on chemical safety for human health protection, principles of toxicity, hazard identification, risk assessment, factors involved in risk assessment, and risk evaluation and implications for risk management.

Pharmacokinetics and pharmacodynamic effects of nicotine nasal spray devices on cardiovascular and pulmonary function.

BACKGROUND: A nasal spray form of nicotine replacement therapy (Nicotrol NS, McNeil Consumer Products Co, Fort Washington, Pa) has been approved and, because of its rapid absorption across the nasal mucosa, may be more effective than nicotine gum or transdermal patches. We tested the hypothesis that the nicotine absorbed into the nasal mucosa would produce significant changes in hemodynamics and pulmonary function in 20 healthy, nonsmoking men and women. METHODS: In this double-blind, randomized study of Nicotrol NS versus placebo, we measured serum nicotine concentrations, blood pressure, heart rate, and indices of pulmonary function at timed intervals before and after nasal spray administration of 3 mg of nicotine. RESULTS: A peak serum nicotine concentration of 4.71 +/- 3.16 ng/mL occurred 10 minutes after drug administration. The maximum change in systolic blood pressure occurred 5 minutes after dosing and was significantly related to nicotine administration (7.1 +/- 9.4% for the nicotine group vs -1.6 +/- 7.3% for the placebo; P = 0.03). In contrast, neither diastolic blood pressure (P = 0.8) nor heart rate (P = 0.07) changed significantly after nicotine administration, when compared with placebo. Pulmonary function was not altered acutely by a single inhalation of nicotine. Pharmacokinetic modeling revealed a classic one-compartment model in which nicotine is absorbed into the systemic circulation by a zero-order process and eliminated by a first-order process. CONCLUSIONS: In this population of nonsmokers, hemodynamic effects of the nicotine nasal spray were observed shortly after administration and before the peak serum nicotine concentration.

New phenotypes associated with the swallow gene of Drosophila: evidence for a general role in oocyte cytoskeletal organization.

During oogenesis in Drosophila, several mRNAs and proteins are localized to discrete regions of the developing oocyte, resulting in a mature oocyte with a well-defined anterior-posterior axis. The product of the swallow (sww) gene is required for the localization of two different mRNAs during oogenesis, bicoid (bcd) and Adducin-like/hu-li tai shao (hts). We initiated a detailed characterization of the phenotypes associated with each of eight sww alleles as a means of investigating the role of sww in oogenic patterning. RNA localization defects in various sww mutants were examined by radioactive in situ hybridization to paraffin sections. Using this technique, several previously unreported RNA localization defects have been observed. Although bcd RNA localization is often lost completely in sww oocytes, in a high proportion of cases, bcd RNA is localized inappropriately along the periphery of the mature oocyte. In several sww mutants, a portion of the bcd mRNA population becomes concentrated at the posterior pole of the oocyte during late oogenesis. Several sww mutations also result in oskar RNA localization defects, consistent with a global role for sww in cytoskeletal regulation or organization. A detailed temporal and spatial analysis of hts RNA localization in sww mutants and in drug-treated ovaries reveals many similarities to bcd RNA localization, and implies the two independent localization events are accomplished by the same mechanism.

Transmissible spongiform encephalopathies, hypotheses and food safety: an overview.

The transmissible spongiform encephalopathies (TSEs) (in both humans and animals) have been reviewed with the principal focus on bovine spongiform encephalopathy (BSE), its recent outbreak amongst cattle in the UK ('mad cow disease') and its sequelae. The possible reasons for this outbreak are discussed as well as a number of hypotheses reviewed for TSEs (e.g. prions, organophosphates, etc.) and current measures attendant with food safety and surveillance taken in the European Union. It is generally accepted that the combined weight of all the evidence to date supports the conclusion that the new rare but lethal variant Creutzfeldt-Jacob Disease (vCJD) is the human counterpart of the aetiological agent BSE and that eating meat from the infected animals is probably to blame for 24 deaths (23 in the UK and one in France) to date from vCJD. Considerable evidence from biochemical, immunologic, pathologic and genetic studies strongly suggests that PrpSC is the major component of the transmissible prion particle responsible for the rare fatal brain TSE diseases.

Multiple chemical sensitivities: an overview.

At the present time multiple chemical sensitivities (MCS) is generally acknowledged to be a poorly understood clinical syndrome which is exhibited by individuals exposed to low levels of exposure to environmental agents that the general population tolerate quite well. A wide range of individual symptoms (typically multiple and related to neurologic, endocrine/metabolic, and immunological, often occurring simultaneously) are displayed by MCS patients. Questions concerning whether or not MCS is a real clinical condition, a form of psychiatric illness or a combination of both remain to be unambiguously clarified.

Exposure from occupational versus other sources.

There is an increasing need to consider the various routes of exposure to individuals in occupational settings, as well as the exposure of the general public to a broad spectrum of carcinogens. The need to consider indoor environments is increasingly recognized in light of the amount of time spent indoors by a large majority of the population and the recognition that levels of certain toxicants are higher indoors than outdoors. This overview highlights (i) a general comparison of exposure to indoor and outdoor levels of 12 volatile organic compounds and (ii) the exposure of workers and the general public to benzene, 1,3-butadiene, formaldehyde, styrene, tetrachloroethylene, phthalate esters, polychlorinated dibenzofurans, radon, and electromagnetic fields.

Technological changes in cancer prevention.

Exposures and technologies in the workplace are changing due to a variety of factors, including newly developed technologies, mechanization and automation, and improvements in industrial hygiene primarily effected in many developed countries. In addition substitution and removal of carcinogenic constituents in the workplace and general environment are increasing in a number of instances, particularly in North America, Western Europe, and Japan, and they are being accompanied as well by remediation either by source reduction, recycling, or compliance to more stringent national and international regulations and standards. This overview highlights some of the strategies employed in the technological changes in cancer prevention and cites examples in source reduction, changes in formulation, product or process changes, recycling, and hazardous materials management.

Approaches for assessing health risks from complex mixtures in indoor air: a panel overview.

Critical to a more definitive human health assessment of the potential health risks from exposure to complex mixtures in indoor air is the need for a more definitive clinical measure and etiology of the health effects of complex mixtures. This panel overview highlights six of the eight presentations of the conference panel discussion and features a number of the major topical areas of indoor air concern. W. G. Meggs assessed clinical research priorities with primary focus on the role of volatile organic chemicals in human health, recognizing the areas where definitive data are lacking. By recognizing many types of chemical sensitivity, it may be possible to design studies that can illuminate the mechanisms by which chemical exposure may cause disease. The critically important topic of multiple chemical sensitivity was discussed by N. A. Ashford, who identified four high risk groups and defined the demographics of these groups. P. A. Schulte addressed the issue of biological markers of susceptibility with specific considerations of both methodological and societal aspects that may be operative in the ability to detect innate or inborne differences between individuals and populations. Three case studies were reviewed. H. Anderson discussed the past and present priorities from a public health perspective, focusing on those issues dealing with exposures to environmental tobacco smoke and formaldehyde off-gassing from materials used in mobile home construction. J. J. Osborne described several case studies involving wood smoke exposure to children, with emphasis on the significantly greater occurrence of chronic respiratory symptoms and acute chest illness for children from homes heated with woodburning stoves.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemicals used in the rubber industry.

Hundreds of chemicals and mixtures illustrative of many structural and use categories are employed in the rubber industry. Global utilization of natural rubber and synthetic elastomers as well as rubber-processing chemicals are projected to increase in the foreseeable future. Primary focus is centered on the major rubber processing chemicals and elastomer monomers in regard to their utility, production trends, structural characteristics, nature of potential impurities, and toxicology (primarily carcinogenicity and genotoxicity). Additionally, areas of specific exposure concern and epidemiology in the rubber industry are considered.

[The role of boundary lipids in phase transitions of biological membranes]. / Rol' granichnykh lipidov v fazovykh perekhodakh biologicheskikh membran.

In terms of the Landau thermodynamic expansion the model of lipid-protein interaction is considered for the case of relatively low protein concentrations. It is established that the proteins inserted into the lipid membrane can change its phase transition temperature. The expression determining the region size of the "boundary" lipids is obtained and the connection between the ordering extent of the "boundary" lipids and the sign and the value of the temperature shift of the phase transition is calculated.