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CSA Concentrations (csa + concentration)
Selected AbstractsReactive doping of PAni,CSA and its use in microwave absorbing materialsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 1 2009R. S. Biscaro Abstract Conductive coatings have been studied for static dissipation and as microwave absorbing materials. The doping process of polyaniline (PAni), which makes it conductive, is an important stage that determines the coating performance. For this purpose, polyaniline was doped by reactive processing in a torque rheometer using different molar ratios between PAni and acid (PAni:CSA) at three different temperatures (80, 90, and 100°C). Aqueous solution doping was also used in the ratio of 1:2 of PAni/CSA, with the aim to investigate the influence of different methods of PAni doping on its characteristics and, consequently, on the performance of coatings. Thermal analyses of the processed materials showed that PAni doped by both routes, reactive and solution processing, showed similar behaviors. X-ray diffraction analyses showed a semicrystalline structure for the PAni,CSA doped by reactive processing using high CSA concentrations and temperature. It was also observed that the doping process affects the dispersion of the components into the conductive coatings. Microwave absorption measurements (8,12,GHz) of PU-doped PAni blends showed the dependence of the doping type, the PAni,CSA concentration, and the mixing conditions of the components on the coating performance; it was found up to 99% of attenuation of the incident radiation for some composites in a narrow frequency range. The microwave absorption efficiency of the coating samples prepared by using the reactive doping process indicates the advantage of this methodology over solution doping. Moreover, the reactive process addresses the environmental requirements. Copyright © 2008 John Wiley & Sons, Ltd. [source] Long-term outcome of treatment with intravenous cyclosporin in patients with severe ulcerative colitisINFLAMMATORY BOWEL DISEASES, Issue 2 2004Joris Arts MD Abstract Objectives IV cyclosporin A (CSA) is an effective therapy in patients with severe ulcerative colitis (UC). It remains unclear if this treatment affects the course of the disease in the long run. We investigated the long-term efficacy and safety in 86 patients with ulcerative colitis treated with IV CSA at our center. Methods The records of all patients treated with IV CSA between 11/1992 and 11/2000 were reviewed. Results Seventy-two of 86 patients (83.7%) responded to IV CSA therapy, administered for a mean of 9 ± 2 days. Following the initial treatment, 69 patients (96%) were discharged on oral CSA with mean blood CSA concentrations of 192 ± 55 ng/mL. Azathioprine was added in 64 (89%) patients. A second treatment with CSA was necessary in 11 patients; 1 patient received three courses of IV treatment. The duration of follow-up averaged 773 ± 369 days. Patients who were responders but were still having certain symptoms at discharge had a higher incidence of colectomy during follow-up. Of all initial responders, 18 (25%) underwent colectomy after a mean interval of 178 ± 141 days. The life-table predicts that of all treated patients, 55% will avoid a colectomy during a period of 3 years. Complications of CSA treatment were mostly reversible, but 3 patients (3.5%) died of opportunistic infections (1 of Pneumocystis carinii pneumonia and 2 of Aspergillus fumigatus pneumoniae). One patient with anaphylactic shock caused by the CSA solvent was successfully resuscitated. Conclusions CSA is an effective treatment of the majority of patients with severe attacks of UC, although the toxicity and even mortality associated with its use necessitates careful evaluation, selection, and follow-up. [source] Reactive doping of PAni,CSA and its use in microwave absorbing materialsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 1 2009R. S. Biscaro Abstract Conductive coatings have been studied for static dissipation and as microwave absorbing materials. The doping process of polyaniline (PAni), which makes it conductive, is an important stage that determines the coating performance. For this purpose, polyaniline was doped by reactive processing in a torque rheometer using different molar ratios between PAni and acid (PAni:CSA) at three different temperatures (80, 90, and 100°C). Aqueous solution doping was also used in the ratio of 1:2 of PAni/CSA, with the aim to investigate the influence of different methods of PAni doping on its characteristics and, consequently, on the performance of coatings. Thermal analyses of the processed materials showed that PAni doped by both routes, reactive and solution processing, showed similar behaviors. X-ray diffraction analyses showed a semicrystalline structure for the PAni,CSA doped by reactive processing using high CSA concentrations and temperature. It was also observed that the doping process affects the dispersion of the components into the conductive coatings. Microwave absorption measurements (8,12,GHz) of PU-doped PAni blends showed the dependence of the doping type, the PAni,CSA concentration, and the mixing conditions of the components on the coating performance; it was found up to 99% of attenuation of the incident radiation for some composites in a narrow frequency range. The microwave absorption efficiency of the coating samples prepared by using the reactive doping process indicates the advantage of this methodology over solution doping. Moreover, the reactive process addresses the environmental requirements. Copyright © 2008 John Wiley & Sons, Ltd. [source] How common is delayed cyclosporine absorption following liver transplantation?LIVER TRANSPLANTATION, Issue 2 2005Silvina E. Yantorno The mean time to peak absorption of cyclosporine (CsA) in liver transplant patients is approximately 2 hours, but in some patients the peak occurs later. The goal of this study was, therefore, to investigate the incidence of delayed absorption in 27 de novo liver transplant recipients receiving CsA ,10 mg/kg/day (C2 monitoring) and in 15 maintenance patients. Patients were categorized as ,normal' absorbers (C2 exceeding C4 and C6) or ,delayed' absorbers (C4 or C6 exceeding C2), and as ,good' (>800 ng/mL at C0, C2, C4, or C6) or ,poor' absorbers (C0, C2, C4 and C6 <800 ng/mL) on the day of study. Among de novo patients, 15 (56%) had ,normal' CsA absorption and 12 (44%) ,delayed' absorption. Good CsA absorption occurred in 16 patients (59%) and poor absorption in 11 (41%). The proportion of poor absorbers was similar in patients with normal (6 / 15, 40%) or delayed (5 / 12, 42%) absorption. Among the 12 delayed absorbers, 11 had peak CsA concentration at C4. Mean C0 level was significantly higher in delayed absorbers (282 ± 96 ng/mL) than in normal absorbers (185 ± 88ng/mL; P = .01). Delayed absorbers reverted to normal absorption (C2 > C4) after a median of 6 days from the day of study, and no cases of delayed absorption were found among maintenance patients. In conclusion, almost 50% of the patients had delayed CsA absorption early posttransplant; around half of these exhibited normal CsA exposure. Measurement of C4 in addition to C2 differentiates effectively between delayed and poor absorbers of CsA such that over- or underimmunosuppression can be avoided. (Liver Transpl 2005;11:167,173.) [source] Pharmacokinetic monitoring of intravenous cyclosporine A in pediatric stem-cell transplant recipients.PEDIATRIC TRANSPLANTATION, Issue 4 2009The trough level is not enough Abstract:, In order to monitor CsA serum levels after SCT, trough levels (C0) are widely used. The aim of this study was to estimate the population and individual PK parameters for patients receiving intravenous CsA after SCT. In 27 pediatric patients after SCT receiving CsA (3 mg/kg/day) every 12 h, a total of 289 CsA concentrations was obtained. To describe the PK parameters of CsA, a two-compartment model with first order elimination was used. Covariate analysis identified body weight, age, and the co-administration with itraconazole and tobramycine as factors influencing the Cl. The statistical comparison of AUC, trough level, and C2 indicates a correlation between AUC and C2, but no correlation between the AUC and C0, r = 0.24 (p = 0.146) vs. r = 0.526 (p = 0.000692), respectively. Our results underscore the fact that CsA trough levels do not reflect the drug exposure in patients receiving intravenous CsA after SCT. By contrast, CsA blood levels measured 2,6 h after CsA infusion showed a better correlation with the AUC. Our data provide new information to optimize the balancing act between GvHD-prophylaxis, graft vs. leukemia effect, and CsA side-effects after SCT. [source] | ||||||||||