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41.
42.
Adenovirus infection of CD34+ hematopoietic stem/progenitor cells is dependent on the multiplicity of infection (MOI), time of incubation, the volume in which the co-incubation occurs and the presence or absence of growth factors. Studies revealed that a brief co-incubation (1-8 hours), resulted in low levels of transgene expression, suggesting that adenovirus infection of CD34+ cells occurs slowly, and optimal transduction requires a 24 hour exposure to adenovirus. Infection by Ad/beta-gal or Ad/p53 at a MOI of 500:1 provided a high transduction efficiency but inhibited hematopoietic function. However, treatment at a MOI of 50-100 resulted in efficient transduction (10.7-15.7% positive) without detectable toxicity. Secondary proof of adenovirus transgene expression was demonstrated by detection of mRNA for p53 in Ad/p53 infected stem cells. We conclude that a 24 hour exposure to recombinant adenovirus encoding p53 or beta-gal, at a MOI of 50-100 is optimal for in vitro gene transfer to BM cells and has no significant effect on hematopoietic function. Adenovirus-mediated transduction of BM cells can also be modulated by growth factors (IL-3, GM-CSF and G-CSF) with improved gene delivery and maintenance of hematopoietic function. In summary, adenovirus vectors can be used to transiently transduce stem cells, and conditions have been defined to maximize expression and limit inhibitory effects on CD34+ cells. These data support continued investigation of this vector for local cytokine delivery and purging of stem cell products.  相似文献   
43.
Air re-oxidation of fully reduced human endothelin-1 under optimized conditions yields the natural isomer with parallel disulfide bridges and the non-natural isomer with crossed disulfide bridges at a ratio of 3:1. In view of the recently determined highly reducing redox potential of selenocysteine (-381 mV) in peptides, the half-cystine residues Cys3 and Cys11 of the natural isomer of endothelin-1 were replaced by selenocysteine. Taking advantage of the high stability of the diselenide group toward reducing agents for disulfides a regioselective disulfide bridging of the second cysteine pair allowed for straightforward preparation of the [Sec3,Sec11, Nle7]-endothelin-1. NMR structural analysis showed conformational preferences of this endothelin analog that were identical to those of the natural hormone. Similarly, the bioactivity data confirmed that replacement of cysteine residues with selenocysteine was without detectable effect on receptor recognition and signal transduction. Both findings strongly support that the exchange of sulfur against selenium produces a fully isomorphous molecule as recently observed for similar exchanges at the level of methionine residues in proteins. Moreover, oxidative refolding of the fully reduced [Sec3,Sec11,Nle7]-endothelin-1 fulfilled the expectation that the redox potential of the selenocysteines would dictate quantitative formation of the natural isomer. These results suggest that the selenocysteine approach, besides offering an interesting chemical tool for induction of correct oxidative folding of multiple cysteine-containing peptides, should even allow for the preparation of non-natural isomers and thus for studying conformational preferences of folding intermediates in peptides and proteins.  相似文献   
44.
Two patients with polymyositis (PM) or dermatomyositis (DM) complicated with massive pleural effusion are reported here. Both patients presented a high-grade fever, pleural effusion prominent on the right, and good response to steroid therapy. In a 50-year-old woman with PM, combined process of pleural inflammation, cardiomyopathy and coexisting hypothyroidism were considered to be responsible for the accumulation of the massive pleural effusion. However, in a 34-year-old man with DM, pleural inflammation associated with interstitial pneumonia or pleural microvasculopathy in DM was considered to be responsible for the accumulation of the massive pleural effusion.  相似文献   
45.
BACKGROUND: Sulphidoleukotrienes (slt) are important mediators in allergic diseases that are synthesized after allergen-specific stimulation. OBJECTIVES: The aim of this study is to determine in vitro slt production after allergen-specific (Dermatophagoides pteronyssinus) stimulus of peripheral blood leucocytes and to observe whether histamine release in whole blood with the same allergen correlates with slt production. We also wanted to evaluate whether a correlation exists between the release of slt and histamine and other diagnostic procedures as well as various clinical situations. METHODS: We studied 62 patients sensitive to Dermatophagoides pteronyssinus (Der p), 30 atopic controls and 12 healthy donors. We determined slt production using the CAST-ELISA technique and histamine release using two concentrations of Der p extract (20 and 2 ng/mL). We also carried out quantification of specific and total IgE levels, skin tests and pulmonary function test on each patient. RESULTS: We observed a significantly increased slt release after in vitro stimulation with Der p. There was a significant difference in the slt release between controls and sensitive patients (P < 0.001) and between atopic controls and sensitive patients (P < 0.001). The data are similar to those obtained with histamine release. We noted a positive correlation (P < 0.001) between slt and histamine release (r = 0.71, at 2 ng/mL and r = 0.83 at 20 ng/mL). We also found a positive (P<0.001), although weak (r=0.4 with at 2ng/mL, and r = 0.34 with P = 0.003 at 20 ng/mL) correlation between slt release and specific IgE levels as well as between slt release and skin-test reactivity (r = 0.49 at 2 ng/mL and r = 0.45 at 20 ng/mL; P < 0.001). No significant correlation between slt release and asthma severity was observed, although a trend toward higher slt production in severe and moderate asthma was detected. We found a significant (P<0.001) but weak (r=-0.3) negative correlation between age and slt release. With respect to sex-related differences, we found significant differences (P < 0.05) in slt release between the sexes with a higher slt release in men than in women. CONCLUSION: We conclude that CAST-ELISA for quantification of slt production is a useful in vitro method for diagnosing sensitization to Der p. There also exists a close correlation between slt release and other parameters of allergic sensitization in vitro as well as in vivo.  相似文献   
46.
The fenestrated endotheliocyte of peritubular and glomerular capillaries in rat and mouse kidneys were observed with SEM and TEM. In the glomerular capillary, so-called "pored-domes" were found not only at the fenestrated areolae but also at the nuclear region of the endotheliocyte. At the region between filtration surface and nuclear region, they accumulated to construct a sponge-like structure. The endotheliocyte of peritubular capillary also showed small "pored-domes". The size and morphology of the pores in the "pored-domes" of glomerular and peritubular capillaries were similar to those of areolae fenestratae of the respective capillary. Based on the findings, we assumed that pored-domes and the sponge-like structure are the reservoir for the fenestrated area of the endotheliocyte to accommodate the rapid expansion of capillary lumen.  相似文献   
47.
An experimental study of the thermodynamic properties of 1,1-difluoroethane   总被引:1,自引:0,他引:1  
Experimental vapor pressures andP--T data of an important alternative refrigerant, 1, 1-difluoroethane (HFC-152a), have been measured by means of a constant-volume method coupled with expansion procedures. SixtyP--T data were measured along eight isochores in a range of temperaturesT from 330 to 440 K, at pressuresP from 1.6 to 9.3 MPa, and at densities from 51 to 811 kg·m–3. Forty-six vapor pressures were also measured at temperatures from 320 K to the critical temperature. The uncertainties of the temperature and pressure measurements are within ±7mK and ±2kPa, respectively, while the uncertainty of the density values is within ±0.1%. The purity of the sample used is 99.9 wt%. On the basis of the measurements along each isochore, five saturation points were determined and the critical pressure was determined by correlating the vapor-pressure measurements. The second and third virial coefficients for temperatures from 360 to 440 K have also been determined.  相似文献   
48.
A binary blend which consists of two incompatible polymers such as poly(vinyl chloride) and polyethylene has been performed through a partial co-crosslinking reaction with peroxide to give a co-crosslinked blend with a uniform dispersion of small polyethylene particles and with an improved mechanical property. The results are obtained through the formation of a co-crosslinked product which acts as a potential solid phase dispersant as well as a well-bonded reinforcing interlayer on polyethylene particles uniformly dispersed in poly(vinyl chloride) matrix. The resulting blends (PVC/PE=10/90 wt) give carbon spherules of 0.5 to 1m diameter through pressure-carbonization at 650° C for 1 h.  相似文献   
49.
This paper introduces a new method of adapting the virtual world of an offline programming model to an actual robotic cell by attaching a CCD camera to the robot. This method requires no specific camera attachment location or optical camera calibration. Furthermore, there is no operational requirement for setting robotic camera location. Robot motion is autonomously generated to identify the camera view line. The view line is adjusted to pass through the designated target point, utilizing visual feedback motion control. This method calibrates reference points between the virtual world of an offline model to an actual robotic cell.  相似文献   
50.
Y. Inoue  Y. Watanabe 《Catalysis Today》1993,16(3-4):487-494
A poled ferroelectric LiNbO3 single crystal with high spontaneous polarization was employed as a catalyst support, and the static and dynamic effects of the polar substrate surfaces on the adsorptive and catalytic properties of thin film catalysts deposited were shown. For the static effect, it was demonstrated that the surface conductivity of copper and metal-free phthalocyanine films increased by the adsorption of NO gas, to a larger extent, when the substrate was the negative polar surface, compared to the positive one. The role of the polar substrates is explained In terms of a band bending model. For the dynamic effect, the Rayleigh surface acoustic wave generated on the LiNbO3 substrate was shown to enhance the catalytic activity for ethanol oxidation on Cu and Ag thin film catalysts deposited on the propagation path. It is proposed that the catalyst activation is mainly due to an electric Held produced. The use of poled LiNbO3 is suggested to be effective for the development of a device-type catalyst with activity controllable functions.  相似文献   
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