881 resultados para Human Factors and Ergonomics
Resumo:
(31)P MRS magnetization transfer ((31)P-MT) experiments allow the estimation of exchange rates of biochemical reactions, such as the creatine kinase equilibrium and adenosine triphosphate (ATP) synthesis. Although various (31)P-MT methods have been successfully used on isolated organs or animals, their application on humans in clinical scanners poses specific challenges. This study compared two major (31)P-MT methods on a clinical MR system using heteronuclear surface coils. Although saturation transfer (ST) is the most commonly used (31)P-MT method, sequences such as inversion transfer (IT) with short pulses might be better suited for the specific hardware and software limitations of a clinical scanner. In addition, small NMR-undetectable metabolite pools can transfer MT to NMR-visible pools during long saturation pulses, which is prevented with short pulses. (31)P-MT sequences were adapted for limited pulse length, for heteronuclear transmit-receive surface coils with inhomogeneous B1 , for the need for volume selection and for the inherently low signal-to-noise ratio (SNR) on a clinical 3-T MR system. The ST and IT sequences were applied to skeletal muscle and liver in 10 healthy volunteers. Monte-Carlo simulations were used to evaluate the behavior of the IT measurements with increasing imperfections. In skeletal muscle of the thigh, ATP synthesis resulted in forward reaction constants (k) of 0.074 ± 0.022 s(-1) (ST) and 0.137 ± 0.042 s(-1) (IT), whereas the creatine kinase reaction yielded 0.459 ± 0.089 s(-1) (IT). In the liver, ATP synthesis resulted in k = 0.267 ± 0.106 s(-1) (ST), whereas the IT experiment yielded no consistent results. ST results were close to literature values; however, the IT results were either much larger than the corresponding ST values and/or were widely scattered. To summarize, ST and IT experiments can both be implemented on a clinical body scanner with heteronuclear transmit-receive surface coils; however, ST results are much more robust against experimental imperfections than the current implementation of IT.
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An enzyme-linked immunosorbent assay (ELISA) for the serological differentiation of cystic (Echinococcus granulosus) and alveolar (E. multilocularis) echinococcosis in man has been evaluated. A discrimination rate of 95.1% was found for 82 sera from patients of geographically disparate endemic areas. This rate was essentially the same as that found for 57 Swiss patients, indicating that inter- and intraspecific strain differences do not influence the test results. The assay method is suitable for immunodiagnostic purposes as well as for seroepidemiological studies.
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Testosterone hydroxylation was investigated in human, canine and equine liver microsomes and in human and canine single CYPs. The contribution of the CYP families 1, 2 and 3 was studied using chemical inhibitors. Testosterone metabolites were analyzed by HPLC. The metabolites androstenedione, 6β- and 11β-hydroxytestosterone were found in microsomes of all species, but the pattern of metabolites varied within species. Androstenedione was more prominent in the animal species, and an increase over time was seen in equines. Testosterone hydroxylation was predominantly catalyzed by the CYP3A subfamily in all three species. While CYP2C9 did not metabolise testosterone, the canine ortholog CYP2C21 produced androstenedione. Quercetin significantly inhibited 6β- and 11β-hydroxytestosterone in all species investigated, suggesting that CYP2C8 is involved in testosterone metabolism, whereas sulfaphenazole significantly inhibited the formation of 6β- and 11β-hydroxytestosterone in human microsomes, at 60min in equine microsomes, but not in canine microsomes. A contribution of CYP2B6 in testosterone metabolism was only found in human and equine microsomes. Inhibition of 17β-hydroxysteroid dehydrogenase 2 indicated its involvement in androstenedione formation in humans, increased androstenedione formation was found in equines and no involvement in canines. These findings provide improved understanding of differences in testosterone biotransformation in animal species.
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PURPOSE To evaluate risk factors for survival in a large international cohort of patients with primary urethral cancer (PUC). METHODS A series of 154 patients (109 men, 45 women) were diagnosed with PUC in ten referral centers between 1993 and 2012. Kaplan-Meier analysis with log-rank test was used to investigate various potential prognostic factors for recurrence-free (RFS) and overall survival (OS). Multivariate models were constructed to evaluate independent risk factors for recurrence and death. RESULTS Median age at definitive treatment was 66 years (IQR 58-76). Histology was urothelial carcinoma in 72 (47 %), squamous cell carcinoma in 46 (30 %), adenocarcinoma in 17 (11 %), and mixed and other histology in 11 (7 %) and nine (6 %), respectively. A high degree of concordance between clinical and pathologic nodal staging (cN+/cN0 vs. pN+/pN0; p < 0.001) was noted. For clinical nodal staging, the corresponding sensitivity, specificity, and overall accuracy for predicting pathologic nodal stage were 92.8, 92.3, and 92.4 %, respectively. In multivariable Cox-regression analysis for patients staged cM0 at initial diagnosis, RFS was significantly associated with clinical nodal stage (p < 0.001), tumor location (p < 0.001), and age (p = 0.001), whereas clinical nodal stage was the only independent predictor for OS (p = 0.026). CONCLUSIONS These data suggest that clinical nodal stage is a critical parameter for outcomes in PUC.
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We present precise iron stable isotope ratios measured by multicollector-ICP mass spectrometry (MC-ICP-MS) of human red blood cells (erythrocytes) and blood plasma from 12 healthy male adults taken during a clinical study. The accurate determination of stable isotope ratios in plasma first required substantial method development work, as minor iron amounts in plasma had to be separated from a large organic matrix prior to mass-spectrometric analysis to avoid spectroscopic interferences and shifts in the mass spectrometer's mass-bias. The 56Fe/54Fe ratio in erythrocytes, expressed as permil difference from the “IRMM-014” iron reference standard (δ56/54Fe), ranges from −3.1‰ to −2.2‰, a range typical for male Caucasian adults. The individual subject erythrocyte iron isotope composition can be regarded as uniform over the 21 days investigated, as variations (±0.059 to ±0.15‰) are mostly within the analytical precision of reference materials. In plasma, δ56/54Fe values measured in two different laboratories range from −3.0‰ to −2.0‰, and are on average 0.24‰ higher than those in erythrocytes. However, this difference is barely resolvable within one standard deviation of the differences (0.22‰). Taking into account the possible contamination due to hemolysis (iron concentrations are only 0.4 to 2 ppm in plasma compared to approx. 480 ppm in erythrocytes), we model the pure plasma δ56/54Fe to be on average 0.4‰ higher than that in erythrocytes. Hence, the plasma iron isotope signature lies between that of the liver and that of erythrocytes. This difference can be explained by redox processes involved during cycling of iron between transferrin and ferritin.
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Economic globalization and respect for human rights are both highly topical issues. In theory, more trade should increase economic welfare and protection of human rights should ensure individual dignity. Both fields of law protect certain freedoms: economic development should lead to higher human rights standards, and UN embargoes are used to secure compliance with human rights agreements. However the interaction between trade liberalisation and human rights protection is complex, and recently, tension has arisen between these two areas. Do WTO obligations covering intellectual property prevent governments from implementing their human rights obligations, including rights to food or health? Is it fair to accord the benefits of trade subject to a clean human rights record? This book first examines the theoretical framework of the interaction between the disciplines of international trade law and human rights. It builds upon the well-known debate between Professor Ernst-Ulrich Petersmann, who construes trade obligations as human rights, and Professor Philip Alston, who warns of a merger and acquisition of human rights by trade law. From this starting point, further chapters explore the differing legal matrices of the two fields and examine how cooperation between them might be improved, both in international law-making and institutions,in dispute settlement. The interaction between trade and human rights is then explored through seven case studies:freedom of expression and competition law; IP protection and health; agricultural trade and the right to food; trade restrictions on conflict WHO convention on tobacco control; and, finally, human rights conditionalities in preferential trade schemes.
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Vegetation history for the study region is reconstructed on the basis of pollen, charcoal and AMS14C investigations of lake sediments from Lago del Segrino (calcareous bedrock) and Lago di Muzzano (siliceous bedrock). Late-glacial forests were characterised byBetula andPinus sylvestris. At the beginning of the Holocene they were replaced by temperate continental forest and shrub communities. A special type of temperate lowland forest, withAbies alba as the most important tree, was present in the period 8300 to 4500 B.P. Subsequently,Fagus, Quercus andAlnus glutinosa were the main forest components andA. alba ceased to be of importance.Castanea sativa andJuglans regia were probably introduced after forest clearance by fire during the first century A.D. On soils derived from siliceous bedrock,C. sativa was already dominant at ca. A.D. 200 (A.D. dates are in calendar years). In limestone areas, however,C. sativa failed to achieve a dominant role. After the introduction ofC. sativa, the main trees were initially oak (Quercus spp.) and later the walnut (Juglans regia). Ostrya carpinifolia became the dominant tree around Lago del Segrino only in the last 100–200 years though it had spread into the area at ca. 5000 cal. B.C. This recent expansion ofOstrya is confirmed at other sites and appears to be controlled by human disturbances involving especially clearance. It is argued that these forests should not be regarded as climax communities. It is suggested that under undisturbed succession they would develop into mixed deciduous forests consisting ofFraxinus excelsior, Tilia, Ulmus, Quercus and Acer.
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OBJECTIVE To determine whether body weight, body condition score, or various body dimensions were associated with acute thoracolumbar intervertebral disk extrusion or protrusion and whether any of these factors were associated with severity of clinical signs in Dachshunds. DESIGN Cross-sectional clinical study. ANIMALS 75 Dachshunds with (n = 39) or without (36) acute thoracolumbar intervertebral disk extrusion or protrusion. PROCEDURES Signalment, various body measurements, body weight, body condition score, and spinal cord injury grade were recorded at the time of initial examination. RESULTS Mean T1-S1 distance and median tuber calcaneus-to-patellar tendon (TC-PT) distance were significantly shorter in affected than in unaffected dogs. A 1-cm decrease in T1-S1 distance was associated with a 2.1-times greater odds of being affected, and a 1-cm decrease in TC-PT distance was associated with an 11.1-times greater odds of being affected. Results of multivariable logistic regression also indicated that affected dogs were taller at the withers and had a larger pelvic circumference than unaffected dogs, after adjusting for other body measurements. Results of ordinal logistic regression indicated that longer T1-S1 distance, taller height at the withers, and smaller pelvic circumference were associated with more severe spinal cord injury. CONCLUSIONS AND CLINICAL RELEVANCE Results suggest that certain body dimensions may be associated with acute thoracolumbar intervertebral disk extrusion or protrusion in Dachshunds and, in affected dogs, with severity of neurologic dysfunction.
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PURPOSE The aim of this study was to analyze the patient pool referred to a specialty clinic for implant surgery over a 3-year period. MATERIALS AND METHODS All patients receiving dental implants between 2008 and 2010 at the Department of Oral Surgery and Stomatology were included in the study. As primary outcome parameters, the patients were analyzed according to the following criteria: age, sex, systemic diseases, and indication for therapy. For the inserted implants, the type of surgical procedure, the types of implants placed, postsurgical complications, and early failures were recorded. A logistic regression analysis was performed to identify possible local and systemic risk factors for complications. As a secondary outcome, data regarding demographics and surgical procedures were compared with the findings of a historic study group (2002 to 2004). RESULTS A total of 1,568 patients (792 women and 776 men; mean age, 52.6 years) received 2,279 implants. The most frequent indication was a single-tooth gap (52.8%). Augmentative procedures were performed in 60% of the cases. Tissue-level implants (72.1%) were more frequently used than bone-level implants (27.9%). Regarding dimensions of the implants, a diameter of 4.1 mm (59.7%) and a length of 10 mm (55.0%) were most often utilized. An early failure rate of 0.6% was recorded (13 implants). Patients were older and received more implants in the maxilla, and the complexity of surgical interventions had increased when compared to the patient pool of 2002 to 2004. CONCLUSION Implant therapy performed in a surgical specialty clinic utilizing strict patient selection and evidence-based surgical protocols showed a very low early failure rate of 0.6%.