Use of perfluorochemical liquid allows earlier detection of gene expression and use of less vector in normal lung and enhances gene expression in acutely injured lung.
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One of the obstacles to successful lung gene transfer is effective delivery of vector to lung, particularly injured or diseased lung. We have previously demonstrated that intratracheal instillation of perfluorochemical (PFC) liquids along with instillation of recombinant adenovirus and adeno-associated virus vectors, or with cationic liposome vectors, increased total lung gene expression and enhanced distribution of gene expression throughout the lung. To further explore the potential benefits of PFC liquid use, we evaluated the effect of PFC liquid instillation on several other aspects of adenovirus-mediated gene expression in lung. Use of PFC liquid resulted in earlier detection of gene expression and allowed the use of less vector to achieve expression comparable to that observed with the use of higher amounts of vector alone. Using PFC liquid also enhanced gene expression in a rodent model of acute lung injury. PFC liquid did cause a transient inflammation when instilled into normal lungs but did not cause any additional inflammation when instilled alone or with adenovirus vector into acutely injured lungs. Thus, PFC liquid may be a useful adjunct for clinical lung gene transfer, particularly for injured or diseased lungs. (+info)
An industrial approach to evaluation of pyrolysis and combustion hazards.
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In addition to the usual toxicology studies necessary for the safe manufacture and use of polymers at room temperature, special studies are needed for polymers which will be used at elevated temperatures. This paper discusses various areas to be investigated and principles for deciding on test materials, tests, and test conditions, polytetrafluoroethylene (PTFE) and fluorinated polyethylene-propylene (PFEP) pyrolysis studies being used as an illustrative case history. Some limitations of animal testing also are mentioned. A toxicological spectrum relating toxicological determinants to PTFE temperature is developed. (+info)
Detection of Ni2+ by a dimethylglyoxime probe using attenuated total-reflection infrared spectroscopy.
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A new analytical approach for the detection of Ni2+ utilizing an attenuated total reflection (ATR) technique is discussed in this paper. Nickel detection was accomplished on a silicon ATR parallelogram crystal uniformly coated by a ca. 1.5-microm Nafion film embedded with dimethylglyoxime (DMG) probe molecules. The detection of Ni2+ is based on the appearance of a unique infrared absorption peak at 1572 cm(-1) that corresponds to the C=N stretching mode in the nickel dimethylglyoximate, Ni(DMG)2, complex. The suitable operational pH range for the nickel infrared sensor is between 6 - 8. High alkalinity in the sample solution causes a leaching of Ni(DMG)2. The detection limit of the nickel infrared sensor is 1 ppm in a sample solution of pH = 8. Interference studies revealed that Cu2+ could compete with Ni2+ for the DMG sites in the Nafion matrix. The new nickel detection methodology can be potentially utilized, after further improvement, in field analysis to locate hot spots contaminated with a high ppm of Ni2+. (+info)
FluoMar, a fluorous version of the Marshall resin for solution-phase library synthesis.
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[structure: see text] The fluorous counterpart of the Marshall resin, 4-(1H,1H,2H,2H-perfluorodecylsulfanyl)phenol (FluoMar), is prepared by S-alkylation of 4-mercaptophenol with C(8)F(17)CH(2)CH(2)I and employed in the synthesis of amide and diamide analogues. The final products are purified by solid-phase extraction (SPE) over FluoroFlash silica cartridges. (+info)
DYSPHONIA DUE TO UNILATERAL NERVE PARALYSIS. TREATMENT BY THE INTRACORDAL INJECTION OF SYNTHETICS--A PRELIMINARY REPORT.
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The injection treatment of unilateral recurrent vocal cord nerve paralysis, successfully performed 40 years ago with paraffin, has recently been reintroduced with non-reactive synthetics. Improvement in the voice far and above that which can be achieved by voice therapy or any practicable surgical procedure has been demonstrated by several investigators. The technique is relatively simple, and there are no significant untoward reactions. Judging from experimental and clinical studies with these inert materials when introduced into other parts of the body, adverse long range effects are not likely to occur in the larynx. Eleven of 12 patients treated by injection of silicone or Teflon paste had substantial improvement in vocal quality and strength. Silicone was absorbed slowly from the injection site and the improvement was not enduring; when Teflon was used, it stayed at the site and the improvement was sustained. (+info)
In vitro and short-term in vivo characteristics of a Kel-F thin film modified glucose sensor.
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A new outer layer composition, consisting of polytetrafluoroethylene (PTFE), Kel-F oil, and Nafion, is suggested to minimize the detrimental effect of dissolved oxygen and to extend the linear response range of a glucose oxidase(GOx)-based sensor using nonconducting polymer. The morphology of Kel-F/PTFE/Kel-F/Nafion polymeric laminate was followed during fabrication by SEM. When Kel-F film was formed on the PTFE outer layer, the linear response was extended to 21 mM, at a sensitivity of 2.8 +/- 0.8 nA/mM mm2. We demonstrate that a sensor without Kel-F/PTFE/Kel-F/Nafion outer layer is relatively oxygen dependent, whereas by comparison a sensor with Kel-F/PTFE/Kel-F/Nafion outer layer is oxygen independent. The current of such a glucose sensor implanted in the subcutaneous tissue stabilized within 60 min, and the lag between blood glucose changes and sensor output was within 1 min. The in vivo characteristics of the glucose sensor described show great promise for one-point in vivo calibration. (+info)
Determination of trace procaine hydrochloride by differential pulse adsorptive stripping voltammetry with a Nafion modified glassy carbon electrode.
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A sensitive and selective method for the determination of procaine hydrochloride with a Nafion-modified glassy carbon electrode has been developed. The voltammetric behavior of procaine hydrochloride on the Nafion-modified electrode indicated that the modified electrode not only increased the sensitivity of the determination of procaine hydrochloride, but also catalyzed the electrode process. Procaine hydrochloride was accumulated in Britton-Robinson buffer (pH 2.09) at a potential of -0.2 V (vs. SCE) for 180 s, and was then determined by differential pulse adsorptive stripping voltammetry. The effect of various parameters, such as the pH of the medium, the mass of drop-coated Nafion, the accumulation potential, the accumulation time and the scan rate, were investigated. Under the optimum conditions, a linear calibration graph was obtained in the concentration range of 6.0 x 10(-8) to 6.0 x 10(-6) mol l(-1) with a correlation coefficient of 0.9987. The relative standard deviation was 4.18% for eight successive determinations of 1.0 x 10(-7) mol l(-1) procaine hydrochloride, and the detection limit (three times signal to noise) was 7.0 x 10(-9) mol l(-1). A study of interfering substances was also performed, and the method was applied to the direct determinations of procaine hydrochloride in the injection solution of procaine hydrochloride and in rabbit serum. (+info)
Differential pulse anodic stripping voltammetric determination of traces of copper with a tobramycin-Nafion modified electrode.
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A Nafion-modified glassy carbon electrode incorporated with tobramycin for the voltammetric stripping determination of Cu2+ has been explored. The electrode was fabricated by tobramycin containing Nafion on the glassy carbon electrode surface. The modified electrode exhibited a significantly increased sensitivity and selectivity for Cu2+ compared with a bare glassy carbon electrode and the Nafion modified electrode. Cu2+ was accumulated in HAc-NaAc buffer (pH 4.6) at a potential of -0.6 V (vs. SCE) for 300 s and then determined by differential pulse anodic stripping voltammetry. The effects of various parameters, such as the mass of Nafion, the concentration of tobramycin, the pH of the medium, the accumulation potential, the accumulation time and the scan rate, were investigated. Under the optimum conditions, a linear calibration graph was obtained in the concentration range of 1.0 x 10(-9) to 5.0 x 10(-7) mol l(-1) with a correlation coefficient of 0.9971. The relative standard deviations for eight successive determinations were 4.3 and 2.9% for 1.0 x 10(-8) and 2.0 x 10(-7) mol l(-1) Cu2+, respectively. The detection limit (three times signal to noise) was 5.0 x 10(-10) mol l(-1). A study of interfering substances was also performed, and the method was applied to the direct determination of copper in water samples, and also in analytical reagent-grade salts with satisfactory results. (+info)