The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Elias Davidneto - One of the best experts on this subject based on the ideXlab platform.
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development of an abbreviated mycophenolic acid area under the time Concentration Curve for renal transplant patients under enteric coated mycophenolate sodium a comparison with critical analysis of available equations
Therapeutic Drug Monitoring, 2018Co-Authors: Elias Davidneto, Ana Heloisa Kamada Triboni, Fernanda Ramos, Fabiana Agena, Paschoalina RomanoAbstract:BACKGROUND: Enteric-coated mycophenolate sodium is frequently used in renal transplantation. The pharmacokinetic profile of mycophenolic acid (MPA) shows a broad range of time-to-maximum Concentration (Tmax) that limits the use of a single MPA Concentration to calculate the area under the time-Concentration Curve (AUC). For both research and clinical MPA monitoring, measuring a complete AUC is troublesome to the center and patients. METHODS: We obtained 171 complete MPA-AUC12h (0, 20, 40, 60, 90, 120, 180, 240, 360, 480, 600, and 720 minutes) from 59 adult (54 ± 16 years) patients (29 men and 43 whites) who have been receiving stable doses of tacrolimus/enteric-coated mycophenolate sodium and steroids. We used the 59 Curves drawn at 31 ± 4 days after transplantation to develop the abbreviated equations, and the remaining 112 Curves drawn at 109 ± 59 days were used to validate them. We used 5 other proposed equations to estimate MPA-AUC (eAUC) (4 with enzyme-multiplied immunoassay technique assay and one with high-performance liquid chromatography [HPLC]) and then used these results to compare with our measured AUC, the bias, and the 10% and 30% accuracy. MPA was measured by ultraperformance liquid chromatography coupled to a tandem mass spectrometry, and AUC was calculated by the trapezoidal rule. RESULTS: For both MPA-measuring methods, enzyme-multiplied immunoassay technique and ultraperformance liquid chromatography coupled to a tandem mass spectrometry, the Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo (HCFMUSP) equations, and others that measure MPA up to 6 hours after the dose had an acceptable low bias with more results in the 10%-30% range than those using data collected until 4 hours. A highly adequate eAUC is obtained using blood collected at 8 hours. CONCLUSIONS: This analysis offers blood-sampling alternatives for MPA monitoring depending on the precision needed.
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a strategy to calculate cyclosporin a area under the time Concentration Curve in pediatric renal transplantation
Pediatric Transplantation, 2002Co-Authors: Elias Davidneto, Lilian M. P. Araujo, Cristiane Feres Alves, Elisa Midori Yagyu, William Carlos Nahas, Nairo N. Sumita, Pascoalina Romano, Luiz Estevam IanhezAbstract:The complete area under the time-Concentration Curve (A UC) is considered the gold standard for cyclosporin A (CsA) monitoring, particularly in pediatric kidney graft recipients who have great absorption and drug clearance variability. However, complete A UCis time-consuming and expensive. For this reason, we retrospectively reviewed 131 complete 4-h A UC (AUC 0 - 4 ) performed in 34 children (mean age 10.6′ 2 yr) in order to construct an equation to calculate AUC 0 - 4 . The median time after transplantation was 540 (range: 247-1,358) days. Multiple regression analysis was performed eitherwith a single variable orwith a combination of two variables. CsA blood Concentration at the second hour after the oral morning dose (C2) was the best predictor of A UC 0 - 4 , where AUC 0 - 4 =424+(2.65×C2), R 2 =0.81, p <0.001. Only the combination of C1 and C2 offered mathematical improvement over the C2 equation. The same analysis was made for pharmacokinetic Curves performed earlier than 6 months (79′55 days, range 8-169 days) and after 1 yr of transplantation. In both time-periods, C2 was the best parameter to use to calculate AUC 0 - 4 . The equations obtained during these two time-periods were very close to the one for the whole population. Our data shows that C2 can be safely used to estimate AUC 0 - 4 . However, for values above 4,000 ng/ h/mL, the formula overestimates the trapezoidal AUC 0 - 4 . The C2 equation simplifies the CsA monitoring as a result of its high predictive value and clinical feasibility.
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sampling strategy to calculate the cyclosporin a area under the time Concentration Curve
American Journal of Transplantation, 2002Co-Authors: Elias Davidneto, Lilian M. P. Araujo, Zita M. L. Brito, Cristiane Feres Alves, Francine Brambate Carvalhinho Lemos, Elisa Midori Yagyu, William Carlos Nahas, Luiz Estevam IanhezAbstract:The complete area under the time-Concentration Curve (AUC) is considered to be the gold standard for cyclosporin-A (CyA) monitoring. However, complete AUC is time- and cost-consuming. For this reason, we reviewed 259 4-h AUC (AUC0−4 ) performed in 74 renal transplanted patients in order to construct an equation to calculate AUC0−4. All samples were drawn from one adult population 13 days following transplantation, in order to allow the cyclosporin metabolism to stabilize. Regression analysis was done either with each or with a combination of two variables. Cyclosporin-A blood Concentration at the second hour after the oral dose (C2) was the best predictor of AUC0−4, where AUC0−4= 451 + (2.73 × C2), R2 = 0.87, p < 0.001. The combination of C1 and C2 only, offered a better mathematical improvement to the C2 equation. This equation was further validated in 33 other CyA pharmacokinetic profiles performed in eight patients who had not participated in the equation development. In this new population, the C2 equation excellently predicted the trapezoidal AUC0−4 (R2 = 0.81). Our data shows that C2 can be safely used to estimate AUC0−4. The C2 equation simplifies CyA monitoring because of its high-predictive value and clinical feasibility.
Luiz Estevam Ianhez - One of the best experts on this subject based on the ideXlab platform.
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A strategy to calculate cyclosporin A area under the time-Concentration Curve in pediatric renal transplantation.
Pediatric Transplantation, 2002Co-Authors: Elias David-neto, Lilian M. P. Araujo, Cristiane Feres Alves, Elisa Midori Yagyu, William Carlos Nahas, Nairo N. Sumita, Pascoalina Romano, Luiz Estevam IanhezAbstract:The complete area under the time-Concentration Curve (A UC) is considered the gold standard for cyclosporin A (CsA) monitoring, particularly in pediatric kidney graft recipients who have great absorption and drug clearance variability. However, complete A UCis time-consuming and expensive. For this reason, we retrospectively reviewed 131 complete 4-h A UC (AUC 0 - 4 ) performed in 34 children (mean age 10.6′ 2 yr) in order to construct an equation to calculate AUC 0 - 4 . The median time after transplantation was 540 (range: 247-1,358) days. Multiple regression analysis was performed eitherwith a single variable orwith a combination of two variables. CsA blood Concentration at the second hour after the oral morning dose (C2) was the best predictor of A UC 0 - 4 , where AUC 0 - 4 =424+(2.65×C2), R 2 =0.81, p
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a strategy to calculate cyclosporin a area under the time Concentration Curve in pediatric renal transplantation
Pediatric Transplantation, 2002Co-Authors: Elias Davidneto, Lilian M. P. Araujo, Cristiane Feres Alves, Elisa Midori Yagyu, William Carlos Nahas, Nairo N. Sumita, Pascoalina Romano, Luiz Estevam IanhezAbstract:The complete area under the time-Concentration Curve (A UC) is considered the gold standard for cyclosporin A (CsA) monitoring, particularly in pediatric kidney graft recipients who have great absorption and drug clearance variability. However, complete A UCis time-consuming and expensive. For this reason, we retrospectively reviewed 131 complete 4-h A UC (AUC 0 - 4 ) performed in 34 children (mean age 10.6′ 2 yr) in order to construct an equation to calculate AUC 0 - 4 . The median time after transplantation was 540 (range: 247-1,358) days. Multiple regression analysis was performed eitherwith a single variable orwith a combination of two variables. CsA blood Concentration at the second hour after the oral morning dose (C2) was the best predictor of A UC 0 - 4 , where AUC 0 - 4 =424+(2.65×C2), R 2 =0.81, p <0.001. Only the combination of C1 and C2 offered mathematical improvement over the C2 equation. The same analysis was made for pharmacokinetic Curves performed earlier than 6 months (79′55 days, range 8-169 days) and after 1 yr of transplantation. In both time-periods, C2 was the best parameter to use to calculate AUC 0 - 4 . The equations obtained during these two time-periods were very close to the one for the whole population. Our data shows that C2 can be safely used to estimate AUC 0 - 4 . However, for values above 4,000 ng/ h/mL, the formula overestimates the trapezoidal AUC 0 - 4 . The C2 equation simplifies the CsA monitoring as a result of its high predictive value and clinical feasibility.
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Sampling strategy to calculate the cyclosporin-A area under the time-Concentration Curve.
American Journal of Transplantation, 2002Co-Authors: Elias David-neto, Lilian M. P. Araujo, Zita M. L. Brito, Cristiane Feres Alves, Francine Brambate Carvalhinho Lemos, Elisa Midori Yagyu, William Carlos Nahas, Luiz Estevam IanhezAbstract:The complete area under the time-Concentration Curve (AUC) is considered to be the gold standard for cyclosporin-A (CyA) monitoring. However, complete AUC is time- and cost-consuming. For this reason, we reviewed 259 4-h AUC (AUC0−4 ) performed in 74 renal transplanted patients in order to construct an equation to calculate AUC0−4. All samples were drawn from one adult population 13 days following transplantation, in order to allow the cyclosporin metabolism to stabilize. Regression analysis was done either with each or with a combination of two variables. Cyclosporin-A blood Concentration at the second hour after the oral dose (C2) was the best predictor of AUC0−4, where AUC0−4= 451 + (2.73 × C2), R2 = 0.87, p
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sampling strategy to calculate the cyclosporin a area under the time Concentration Curve
American Journal of Transplantation, 2002Co-Authors: Elias Davidneto, Lilian M. P. Araujo, Zita M. L. Brito, Cristiane Feres Alves, Francine Brambate Carvalhinho Lemos, Elisa Midori Yagyu, William Carlos Nahas, Luiz Estevam IanhezAbstract:The complete area under the time-Concentration Curve (AUC) is considered to be the gold standard for cyclosporin-A (CyA) monitoring. However, complete AUC is time- and cost-consuming. For this reason, we reviewed 259 4-h AUC (AUC0−4 ) performed in 74 renal transplanted patients in order to construct an equation to calculate AUC0−4. All samples were drawn from one adult population 13 days following transplantation, in order to allow the cyclosporin metabolism to stabilize. Regression analysis was done either with each or with a combination of two variables. Cyclosporin-A blood Concentration at the second hour after the oral dose (C2) was the best predictor of AUC0−4, where AUC0−4= 451 + (2.73 × C2), R2 = 0.87, p < 0.001. The combination of C1 and C2 only, offered a better mathematical improvement to the C2 equation. This equation was further validated in 33 other CyA pharmacokinetic profiles performed in eight patients who had not participated in the equation development. In this new population, the C2 equation excellently predicted the trapezoidal AUC0−4 (R2 = 0.81). Our data shows that C2 can be safely used to estimate AUC0−4. The C2 equation simplifies CyA monitoring because of its high-predictive value and clinical feasibility.
Keisuke Fukui - One of the best experts on this subject based on the ideXlab platform.
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Concentration of sodium chloride in aqueous solution by chlorodifluoromethane gas hydrate
Chemical Engineering and Processing, 2008Co-Authors: Kouji Maeda, Yoko Katsura, Yusuke Asakuma, Keisuke FukuiAbstract:Abstract The decomposition temperature and pressure (quadruple point) of chlorodifluoromethane (R22) gas hydrate in aqueous sodium chloride (NaCl) solution was measured at different NaCl Concentrations in the solution as a phase diagram. The operative Concentration Curve of NaCl was obtained as a function of temperature. The maximum decomposition temperature of R22 hydrate was about 290 K at 0.9 MPa pressure, and it decreased as the NaCl Concentration increased in the solution. R22 hydrate caused supercooling, and the supercooling occurrence temperature was much lower than the decomposition temperature. The ultrasonic charge reduced the supercooling of hydration effectively even though the ultrasonic charge did not change the decomposition temperature at all. The Concentration experimental results from the several NaCl solutions having different NaCl Concentrations were in good agreement with the theoretical operative Concentration Curve for NaCl.
D. D. Koleske - One of the best experts on this subject based on the ideXlab platform.
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method for determining the radiative efficiency of gainn quantum wells based on the width of efficiency versus carrier Concentration Curve
Applied Physics Letters, 2012Co-Authors: Qifeng Shan, Andrew J Birkel, Fred E Schubert, Mary H Crawford, Karl R Westlake, D. D. KoleskeAbstract:We report a method to determine the radiative efficiency (RE) of a semiconductor by using room-temperature excitation-dependent photoluminescence measurements. Using the ABC model for describing the recombination of carriers, we show that the theoretical width of the RE-versus-carrier-Concentration (n) Curve is related to the peak RE. Since the normalized external quantum efficiency, EQEnormalized, is proportional to the RE, and the square root of the light-output power, LOP, is proportional to n, the experimentally determined width of the EQEnormalized-versus-n Curve can be used to determine the RE. We demonstrate a peak RE of 91% for a Ga0.85In0.15N quantum well.
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Internal quantum efficiency in light-emitting diodes based on the width of efficiency-versus-carrier-Concentration Curve
2012 Conference on Lasers and Electro-Optics (CLEO), 2012Co-Authors: Q. Shan, A. J. Birkel, E. F. Schubert, D. D. Koleske, M. H. CrawfordAbstract:Based on the ABC model, we derive a relationship between the internal quantum efficiency (IQE) and the width of the efficiency-versus-carrier-Concentration Curve. We determine the IQE of LEDs at temperatures ranging from 100K to 300K.
M G Svaland - One of the best experts on this subject based on the ideXlab platform.
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iopentol in patients with chronic renal failure its effects on renal function and its use as glomerular filtration rate parameter
Scandinavian Journal of Clinical & Laboratory Investigation, 1992Co-Authors: K J Berg, F Kolmannskog, P E Lillevold, K P Nordal, L Ressem, K Rootwelt, M G SvalandAbstract:Iopentol (mean dose 0.42 g I kg−1) was administered for abdominal aortography and pelvic angiography in 10 patients with advanced non-diabetic chronic renal failure (S-creatinine 672±259 μmol l−1, mean±SD). Renal glomerular function measured as creatinine clearance and plasma clearance of [99Tcm]-diethyl-enetriaminepentaacetic acid (DTPA) was unchanged by iopentol, as also was urinary excretion of the renal tubular enzymes N-acetyl-β-glucosaminidase (NAG) and alkaline phosphatase (ALP). The elimination of iopentol from serum and urine was delayed, and detectable serum and urine Concentrations were found 5 days after administration of the contrast medium. Creatine clearance was 47% higher than the corresponding renal iopentol clearance. Plasma iopentol clearance, measured as the total area under the plasma Concentration Curve, was 40% higher than renal iopentol clearance because of extrarenal elimination of iopentol. We conclude that abdominal aortography with iopentol can be performed without effects on r...