5,074 research outputs found

    Elemental bio-imaging of thorium, uranium, and plutonium in tissues from occupationally exposed former nuclear workers

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    Internal exposure from naturally occurring radionuclides (including the inhaled long-lived actinides 232Th and 238U) is a component of the ubiquitous background radiation dose (National Council on Radiation Protection and Measurements. Ionizing radiation exposure of the population of the United States; NCRP Report No. 160; NCRP: Bethesda, MD, 2009). It is of interest to compare the concentration distribution of these natural ?-emitters in the lungs and respiratory lymph nodes with those resulting from occupational exposure, including exposure to anthropogenic plutonium and depleted and enriched uranium. This study examines the application of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS) to quantifying and visualizing the mass distribution of uranium and thorium isotopes from both occupational and natural background exposure in human respiratory tissues and, for the first time, extends this application to the direct imaging of plutonium isotopes. Sections of lymphatic and lung tissues taken from deceased former nuclear workers with a known history of occupational exposure to specific actinide elements (uranium, plutonium, or americium) were analyzed by LA-ICPMS. Using a previously developed LA-ICPMS protocol for elemental bio-imaging of trace elements in human tissue and a new software tool, we generated images of thorium (232Th), uranium (235U and 238U), and plutonium (239Pu and 240Pu) mass distributions in sections of tissue. We used a laboratory-produced matrix-matched standard to quantify the 232Th, 235U, and 238U concentrations. The plutonium isotopes 239Pu and 240Pu were detected by LA-ICPMS in 65 ?m diameter localized regions of both a paratracheal lymph node and a sample of lung tissue from a person who was occupationally exposed to refractory plutonium (plutonium dioxide). The average (overall) 239Pu concentration in the lymph node was 39.2 ng/g, measured by high purity germanium (HPGe) ?-spectrometry (Lynch, T. P.; Tolmachev, S. Y.; James, A. C. Radiat. Prot. Dosim. 2009, 134, 94?101). Localized mass concentrations of thorium (232Th) and uranium (238U) in lymph node tissue from a person not occupationally exposed to these elements (chronic natural background inhalation exposure) ranged up to 400 and 375 ng/g, respectively. In lung samples of occupationally nonexposed to thorium and uranium workers, 232Th and 238U concentrations ranged up to 200 and 170 ng/g, respectively. In a person occupationally exposed to air-oxidized uranium metal (Adley, F. E.; Gill, W. E.; Scott, R. H. Study of atmospheric contaminiation in the melt plant buiding. HW-23352(Rev.); United States Atomic Energy Commission: Oakridge, TN, 1952, p 1?97), the maximum 235U and 238U isotopic mass concentrations in a lymph node, measured at higher resolution (with a 30 ?m laser spot diameter), were 70 and 8500 ng/g, respectively. The ratio of these simultaneously measured mass concentrations signifies natural uranium. The current technique was not sufficiently sensitive, even with a 65 ?m laser spot diameter, to detect 241Am (at an overall tissue concentration of 0.024 ng/g, i.e., 3 Bq/g). © 2010 American Chemical Society

    Agreement in Walking Speed Measured Using Four Different Outcome Measures: 6-Meter Walk Test, 10-Meter Walk Test, 2-Minute Walk Test, and 6-Minute Walk Test

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    Background: Walking speed is considered the sixth vital sign because it is a valid, reliable, and sensitive measure for assessing functional status in various populations. Purpose: The current study assessed agreement in walking speed using the 6-meter walk test, (6MWT) 10-meter walk test (10MWT), 2-minute walk test (2minWT), and 6-minute walk test (6minWT). We also determined differences in walking speed. Methods: Seventy-three healthy adults (44 females, 29 males; mean [SD] age=31.36 [10.33] years) participated. Lafayette Electronic timing devices measured walking speed for the 6MWT and 10MWT. Measuring wheels and stopwatches measured walking distance and speed for the 2minWT and 6minWT. Participants completed 1 trial, and all tests were administered simultaneously. Results: The intraclass correlation coefficient (2, 4) for the different measures of walking speed was excellent at 0.90 (95% confidence intervals, 0.86-0.93). The correlation was 0.95 between 6MWT and 10MWT, 0.94 between 2minWT and 6minWT, 0.67 between 6MWT and 2minWT, 0.63 between 10MWT and 2minWT, and 0.59 between 10MWT and 6minWT (all p \u3c 0.05). No differences in walking speed were found between the four walking tests. Conclusion: Administration of any of the four walking tests provided reliable measurement of walking speed

    What Should a Psychiatrist Know About Genetics? Review and Recommendations From the Residency Education Committee of the International Society of Psychiatric Genetics.

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    The International Society of Psychiatric Genetics (ISPG) created a Residency Education Committee with the purpose of identifying key genetic knowledge that should be taught in psychiatric training programs. Thirteen committee members were appointed by the ISPG Board of Directors, based on varied training, expertise, gender, and national origin. The Committee has met quarterly for the past 2 years, with periodic reports to the Board and to the members of the Society. The information summarized includes the existing literature in the field of psychiatric genetics and the output of ongoing large genomics consortia. An outline of clinically relevant areas of genetic knowledge was developed, circulated, and approved. This document was expanded and annotated with appropriate references, and the manuscript was developed. Specific information regarding the contribution of common and rare genetic variants to major psychiatric disorders and treatment response is now available. Current challenges include the following: (1) Genetic testing is recommended in the evaluation of autism and intellectual disability, but its use is limited in current clinical practice. (2) Commercial pharmacogenomic testing is widely available, but its utility has not yet been clearly established. (3) Other methods, such as whole exome and whole genome sequencing, will soon be clinically applicable. The need for informed genetic counseling in psychiatry is greater than ever before, knowledge in the field is rapidly growing, and genetic education should become an integral part of psychiatric training

    pilF polymorphism-based real-time PCR to distinguish Vibrio vulnificus strains of human health relevance

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    The Gram-negative bacterium Vibrio vulnificus is a common inhabitant of estuarine environments. Globally, V. vulnificus is a significant foodborne pathogen capable of causing necrotizing wound infections and primary septicemia, and is a leading cause of seafood-related mortality. Unfortunately, molecular methods for the detection and enumeration of pathogenic V. vulnificus are hampered by the genetically diverse nature of this pathogen, the range of different biotypes capable of infecting humans and aquatic animals, and the fact that V. vulnificus contains pathogenic as well as non-pathogenic variants. Here we report an alternative approach utilizing the development of a real-time PCR assay for the detection of pathogenic V. vulnificus strains based on a polymorphism in pilF, a gene previously indicated to be associated with human pathogenicity. Compared to human serum reactivity, the real-time PCR assay successfully detected pathogenic strains in 46 out of 47 analysed V. vulnificus isolates (97.9%). The method is also rapid, sensitive, and more importantly can be reliably utilised on biotype 2 and 3 strains, unlike other current methods for V. vulnificus virulence differentiation

    Spiny Mice (\u3cem\u3eAcomys\u3c/em\u3e) Exhibit Attenuated Hallmarks of Aging and Rapid Cell Turnover after UV Exposure in the Skin Epidermis

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    The study of long-lived and regenerative animal models has revealed diverse protective responses to stressors such as aging and tissue injury. Spiny mice (Acomys) are a unique mammalian model of skin wound regeneration, but their response to other types of physiological skin damage has not been investigated. In this study, we examine how spiny mouse skin responds to acute UVB damage or chronological aging compared to non-regenerative C57Bl/6 mice (M. musculus). We find that, compared to M. musculus, the skin epidermis in A. cahirinus experiences a similar UVB-induced increase in basal cell proliferation but exhibits increased epidermal turnover. Notably, A. cahirinus uniquely form a suprabasal layer co-expressing Keratin 14 and Keratin 10 after UVB exposure concomitant with reduced epidermal inflammatory signaling and reduced markers of DNA damage. In the context of aging, old M. musculus animals exhibit typical hallmarks including epidermal thinning, increased inflammatory signaling and senescence. However, these age-related changes are absent in old A. cahirinus skin. Overall, we find that A. cahirinus have evolved novel responses to skin damage that reveals new aspects of its regenerative phenotype
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