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1.
The response to antigen is an important factor in the development of airway inflammation. Segmental bronchoprovocation (SBP) with antigen and subsequent bronchoalveolar lavage (BAL) have provided valuable insight into the mechanisms of allergic inflammation. To determine the features of allergic airway response in asthma, 19 subjects with mild asthma underwent antigen SBP in a dose-dependent manner. The amount of antigen used in SBP was 0 (saline), and 1, 5, or 20% of the antigen dose required to drop the FEV1 by 20% (APD20). BAL was done at 5 min and 48 h after SBP. BAL histamine levels increased modestly 5 min after antigen SBP. At 48 h, there was a marked increase in eosinophils and IL-5 concentration even in airway segments where the release of histamine was small. Moreover, eosinophils correlated with IL-5 levels at 48 h (r = 0.63; p < 0.001), but not with BAL histamine concentrations at 5 min. GM-CSF levels did not increase after antigen SBP and did not correlate with eosinophils. These observations indicate that asthmatic subjects can develop a dose-dependent response to antigen SBP that is characterized by a modest increase in histamine immediately after antigen exposure, and marked eosinophilia, which appears proportionately greater than the histamine response and relatively greater than what is seen in allergic nonasthmatic subjects. This feature might be important to the eventual development of airway inflammation in asthma.  相似文献   
2.
In general, inflammatory cells cross basement membranes by producing proteinases. To investigate the role of proteinases in eosinophil basement membrane migration, we studied peripheral blood eosinophils in Matrigel-coated chemotaxis chambers. Electron microscopy showed degradation of the Matrigel layer when eosinophils, added to the upper chamber, transmigrated the membrane in the presence of both platelet-activating factor (PAF) in the lower chamber and interleukin (IL)-5 in both chambers. In the absence of either or both PAF and IL-5, no changes occurred in the Matrigel layer. Matrigel transmigration of eosinophils induced by PAF and IL-5 was inhibited by 1,10-phenanthroline, batimastat, 3,4-dichloroisocoumarin, chymostatin, and a neutralizing antibody for the matrix metalloproteinase (MMP)-9, indicating that serine proteinase(s) and MMP, specifically MMP-9, were involved in the transmigration of eosinophils through Matrigel. In contrast, eosinophil migration through a bare membrane was not affected by batimastat. Using gelatin zymography and immunoblotting, MMP-9 was detected in the migration upper chamber supernatant of the eosinophil transmigration assay and in the conditioned medium of eosinophils. Release of MMP-9 by eosinophils was increased by IL-5, PAF, or both, but the substrate-degrading activity of MMP-9 was increased only in the presence of both IL-5 and PAF, indicating that the releasing and activating mechanisms of MMP-9 are involved in eosinophil basement membrane migration. This study implicates MMP-9 in basement membrane migration of eosinophils and suggests its involvement in inflammatory diseases where tissue eosinophilia plays a role.  相似文献   
3.
BACKGROUND: With improvements in HIV antibody test (ELISA) performance, the window of time between infection and seroconversion becomes a major source of error in HIV screening. The authors examined its impact on the false-reassurance rate (FRR). METHODS: Test sensitivity was modeled as the product of two factors: the inherent sensitivity (sensitivity when antibody is present) and the probability that antibody is present in infected blood. A model of HIV and AIDS incidence was used to derive an estimate of the probability of remaining in the seronegative window (pw) among those who are infected. With plausible assumptions, this probability approaches 0.03. The FRR was then estimated as a function of the probability of remaining in the seronegative window, the prevalence of HIV, and the inherent sensitivity of the ELISA test were estimated. RESULTS: The FRRs for two blood donor groups, one with an HIV prevalence of 0.004 and a typical probability of remaining in the seronegative window (pw = 0.03) and the other with a higher prevalence of 0.017 but fewer donors in the window (pw = 0.003), are equal (140 per million donors) if the blood is negative on a single ELISA test. After two negative tests or a single test that can detect antibody more reliably, however, the FRR is much higher in the group with the higher pw (= 120 per million compared with 50 per million), because the greater numbers of donors in the window more than offsets the lower prevalence. CONCLUSION: With improvements in inherent sensitivity of ELISA by virtue of technical progress or retesting, the prevalence of HIV infection may no longer play the critical role in degrading the results of blood screening. As inherent test performance improves, tests are increasingly likely to miss infected blood because of the seronegative-window error rather than because of measurement error. Window error plays a proportionally greater role during the early stages of HIV dissemination in a population where the incidence of new HIV infection is high relative to the incidence of AIDS. These findings may explain, in part, the recent observation that cases of transfusion of contaminated blood often take place in areas where AIDS epidemics have started recently. They also suggest that the traditional strategy of soliciting blood donors from low-prevalence populations may not always be optimal, unless such populations are truly low-risk.  相似文献   
4.
Magnetic resonance imaging (MRI) has been established as a reliable and safe imaging method for the human body. However, electric conductors, such as cables situated near or in the human body, should be avoided because induced currents in the cables can cause hazardous heating in the surrounding tissue. In this paper, a new principle for the design of a transmission line is introduced and demonstrated, which is capable of avoiding dangerous heating of cables. The principle is based on transformers placed along the line, splitting the long line into several short not resonant and thus safe sections. A transformer design is introduced along with the theoretical aspects for both the avoidance of the undesired induced currents and the reduction of signal attenuation. Furthermore, the design fulfills the geometrical requirements of the side lumen of a standard catheter. Matching networks, whose elements are determined by power matching, are used to reduce signal attenuation by the transformers. A prototype was built to validate both theory and the simulations. As demonstrated in this work, it is possible to build safe transmission lines for MRI, making applications such as active catheter tracking possible. We expect that even new applications, such as safe intravascular imaging will be possible in a safe manner in the future.  相似文献   
5.
Poly(lactide) (PLA) and poly(methyl methacrylate) (PMMA) are melt compounded with chopped glass fiber using laboratory scale twin‐screw extrusion. Physical properties are examined using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), tensile testing, impact testing, X‐ray computed tomography (CT) scanning, and field emission scanning electron microscopy (FE‐SEM). Molecular weight is determined using gel permeation chromatography (GPC). Miscibility of the blends is implied by the presence of a single glass transition temperature and homogeneous morphology. PLA/PMMA blends tend to show positive deviations from a simple linear mixing rule in their mechanical properties (e.g., tensile toughness, modulus, and stress at break). The addition of 40 wt % glass fiber to the system dramatically increases physical properties. Across all blend compositions, the tensile modulus increases from roughly 3 GPa to roughly 10 GPa. Estimated heat distortion temperatures (HDTs) are also greatly enhanced; the pure PLA sample HDT increases from 75 °C to 135 °C. Fiber filled polymer blends represent a sustainable class of earth abundant materials which should prove useful across a range of applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44868.  相似文献   
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7.
Placental site trophoblastic tumor (PSTT) consists of a neoplastic proliferation of intermediate or extravillous trophoblast (also known as X cells). Pregnancy-associated major basic protein (pMBP) is a marker for placental intermediate trophoblast. We compared the distribution of pMBP and human placental lactogen (hPL) in 24 PSTT and 3 exaggerated placental site (EPS) specimens using two distinct immunohistologic methods. Statistical analyses were used to compare staining intensities in metastatic and nonmetastatic lesions. By immunofluorescence, 77% of the PSTT specimens and 100% of the EPS specimens stained with antibodies to pMBP, and the pMBP was localized in intermediate trophoblast and surrounding extracellular areas. By immunohistochemistry, 78% of the PSTT specimens and 100% of the EPS specimens stained for pMBP with a pattern comparable with that of immunofluorescence. Likewise, by immunohistochemistry, hPL stained 96% of the PSTT specimens and 100% of the EPS specimens. Immunohistochemical staining intensities for pMBP and hPL correlated (r2 = +.24; P = .013), but hPL staining was mainly confined to intermediate trophoblast and was more intense. Anti-pMBP tended to stain metastatic PSTT weakly. Thus, pMBP is a useful marker for intermediate trophoblast tumors and could help distinguish these from other forms of trophoblastic disease.  相似文献   
8.
Pretreatment of polymer glue surfaces by Ip-plasma Low-pressure-plasma-technique represents a modern and high effective method for cleaning and systematical modification of polymer surfaces but also allows the protection of environment. With lp-plasma-technology excellent and reproducible surfacequalities can be produced, without changing any mechanical attribute. A lot of internal process parameters (time, energy, pressure, mixture of process gas) assure the process controlling (plasma), but also many external parameters (material, loading degree, time between pretreatment and application of bonding material, processing-steps before and behind the plasmatreatment) have great influence to the result of the pretreatment. The effect of all these internal and external parameters to the result of pretreatment and the quality of adhesive strength will be discuss by the two polymers PP and PBT.  相似文献   
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10.
Revolution in Place of Evolution – Innovative Foil Technique for Automotive Body Shell Foil techniques represent an innovative option compared to traditional automotive painting. Cost reduction demands and light weight construction has brought forth the requirement to apply polymers at automotive body shells. Particularly, thermoplastic polymers enable a large freedom for the design of modern cars at moderate costs. The foil technique is also a promising approach for an introduction of long glass fibre reinforced thermoplastics into the outer body skin and to reach a Class A finish. One technology is the colormatchable foil technique (CFT). In cooperation with BASF Coatings AG, Münster INPRO developed this new technology to the stage of fundamental feasibility. This new technology stands short before its introduction in practice.  相似文献   
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